Methods

RCT, parallel design

Participants

120 (ASA I ‐ III) participants scheduled for elbow, forearm, wrist, hand surgery

Excluded: Pregnant women, patients < 18 yrs, those with contraindication to RA, such as known allergic reaction to LA, local infection at site of puncture and treatment or disease that severely affects coagulation

Interventions

Ultrasound in‐plane (n = 40) versus ultrasound out‐of‐plane (n = 40) versus nerve stimulation (n = 40)

Axillary brachial plexus block of 4 nerves (median, ulnar, radial, musculocutaneous); each blocked separately with no more than 40 ml in total of 1.5% mepivacaine

Ultrasound: 8 ‐ 13 MHz probe (LOGIQe); endpoint ‐ visualisation of proper spread of the local anaesthetic around the targeted nerves. All 4 nerves blocked with 5‐7ml LA each.

Neurostimulation: pulse duration of 100 µsec, frequency 1 Hz, initial current 1.5 mA. Nerves were located according to specific motor‐evoked muscular contractions. Current reduced to 0.5 mA. 15 ml of LA for median and radial nerves, and 5 ml for the musculocutaneous nerve.

Outcomes

1. Adequacy of block (defined as "presence of complete sensory block of the 5 major nerves", assessed with pinprick and cold sensation)

2. Supplementation rate

3. Complications (paraesthesia, vascular puncture)

4. Time to perform block (labelled in table as "Duration of block placement").

5. Participant discomfort

Notes

4 practitioners described as being experienced in both techniques

For the purpose of analysis, we combined the data from the 2 groups ultrasound with in‐plane and ultrasound with out‐plane technique

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Unclear risk

Sealed envelopes used, but no further details

Allocation concealment (selection bias)

Unclear risk

As above

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Anaesthetist not blinded

Blinding of participants and personnel (performance bias):Complications

High risk

Anaesthetist not blinded

Blinding of participants and personnel (performance bias): time outcomes

High risk

Anaesthetist not blinded

Blinding of participants and personnel (performance bias): Patient discomfort

High risk

Anaesthetist not blinded.

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Unclear risk

Assume assessed by anaesthetist but no details reported

Blinding of outcome assessment (detection bias): Complications

Unclear risk

Assume assessed by anaesthetist but no details reported

Blinding of outcome assessment (detection bias): time outcomes

Low risk

Assessed by independent observer

Blinding of outcome assessment (detection bias): Patient discomfort

Unclear risk

Assessed by independent observer.  No details of whether participant is blinded but assume not

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No apparent losses

Selective reporting (reporting bias)

Unclear risk

Published protocol not sought.  Some expected outcomes not effectively reported – success of block, sensory testing

Baseline characteristics

Low risk

Largely equivalent.

Funding sources

Low risk

None, other departmental funding

Operator expertise

Unclear risk

“Four senior anaesthesiologists experienced in both neurostimulation and ultrasound techniques performed the block”.  Unknown if experience was equivalent and whether participants stratified by anaesthetist.

Methods

RCT, parallel design

Participants

106 ASA I ‐ III participants scheduled for elbow, forearm, wrist or hand surgery

Excluded: age < 18 or > 70 yr, language barrier, contraindication(s) to regional anaesthesia, weight > 100 kg, pre‐existing neurological deficit in the distribution to be anaesthetized, local infection, coagulopathy, chest or shoulder deformities, severe respiratory disease, or clavicle fracture.

Interventions

Ultrasound (n = 53) versus nerve stimulation (n = 53)

Intraclavicular brachial plexus block of radial, ulnar, median and musculocutaneous nerves.

Total volume 30 ml local anaesthetic (2% lidocaine 15 mL and 0.5% bupivacaine 15 mL with epinephrine

1:200,000)

Ultrasound: either linear probe 7 – 13 MHz (Philips/ATL HDI 5000) a 5 – 12 MHz (Philips HD11); endpoint ‐ visualization of lateral and posterior cord, LA injected incrementally to total volume of 30 ml.

Nerve stimulation (Stimuplex): motor endpoints sought (elbow/ finger flexion, thumb opposition, wrist extension) at stimulating current of 0.3 ‐ 0.5 mA. 15 mL of LA injected incrementally at each position for a total of 30 mL.

All participants given midazolam 2 – 4 mg iv as premedication.

For nerve stimulation group, If 2 motor responses were not elicited within 20 min of needle insertion, procedure abandoned in favour of a different approach to brachial plexus blockade, and participant excluded from analysis.

Outcomes

1. Adequacy of block (defined as diminished sensation to pinprick at 20 min, in all 4 nerves)

2. Supplementation rate (requirement for supplemental nerve block, skin infiltration or general anaesthesia). Data not reported in study

3. Complications (cardiorespiratory arrest, seizures, pneumothorax, nerve injury, paraesthesia, vascular puncture, tachycardia)

4. Time to perform block (duration of time from placement of the ultrasound probe on the skin to needle removal or palpation of anatomical landmarks to needle removal)

5. Number of block attempts

6. Participant discomfort during block placement

Notes

One of 4 experienced regional anaesthesiologists ‐ no further details of whether experience is balanced between techniques

Supported by grant funding, equipment received from manufacturers for purpose of study ‐ no interests declared.

Time to perform block reported as median (interquartile range) and therefore not possible to combine in this review

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Computer‐generated randomization table

Allocation concealment (selection bias)

Unclear risk

No details given

Blinding of participants and personnel (performance bias):Complications

High risk

Anaesthetist not blinded

Blinding of participants and personnel (performance bias): time outcomes

High risk

Anaesthetist not blinded

Blinding of participants and personnel (performance bias): Patient discomfort

High risk

Anaesthetist not blinded

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Low risk

Evaluated by blinded observer

Blinding of outcome assessment (detection bias): Complications

Low risk

Evaluated by blinded observer

Blinding of outcome assessment (detection bias): time outcomes

Low risk

Evaluated by blinded observer

Blinding of outcome assessment (detection bias): Patient discomfort

Low risk

Participants blinded with use of 'sham' equipment

Incomplete outcome data (attrition bias)
All outcomes

Unclear risk

Small number of exclusions (5 participants) with clear reasons given. However, only 49% participants available for assessment of complications at postoperative day 7

Selective reporting (reporting bias)

Unclear risk

No data available for pain on injection. Also published protocol not sought

Baseline characteristics

Low risk

Largely comparable, although some differences in types of surgery between groups

Funding sources

High risk

Funding from grants, equipment supplied by named manufacturers. Unclear whether any bias has been introduced

Operator expertise

Unclear risk

Anaesthetists described as experienced but no detail of whether experience is equivalent for both techniques

Methods

RCT, parallel design

Participants

59 patients, ASA I ‐ III, for scheduled forearm, wrist, or hand surgery
Excluded: coagulopathy, local infection, allergy to local anaesthetics, severe cardiac or respiratory disease, diabetes, known neuropathies, chronic opioid use

Interventions

Ultrasound (n = 30) versus nerve stimulation (n = 29)

Axillary brachial plexus block; 4 nerves located individually in both groups (ulnar, radial, median, musculocutaneous); each nerve blocked with 5 ml 0.75% bupivacaine in both groups

Ultrasound: 10 MHz linear probe (GE LOGIQ book XP); endpoint ‐ visualized spread of local anaesthetic around each nerve, needle position moved to allow optimal spread
Nerve stimulation: pulse duration 0.15 msec, initial current density 1 mA, frequency 2 Hz; endpoint ‐ stimulation at < 0.5 mA

Outcomes

1. Block requiring supplementation (defined as "block requiring rescue supplementation or general anaesthesia")

2. Time to achieve surgical block

3. Onset time of block (sensory and motor reported separately)

4. Number of skin punctures or needle passes (defined as any forward movements of the needle preceded by retractions of at 10 mm)

5. Participant discomfort

Notes

2 practitioners with "substantial" experience
1 participant excluded due to failure to locate nerves with nerve stimulator

Results for onset time presented in a graph, not possible to extract data for this review

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Computer‐generated random numbers

Allocation concealment (selection bias)

Unclear risk

"Sealed envelope technique" ‐ no further details

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Anaesthetist not blinded

Blinding of participants and personnel (performance bias):Complications

High risk

Anaesthetist not blinded

Blinding of participants and personnel (performance bias): time outcomes

High risk

Anaesthetist not blinded

Blinding of participants and personnel (performance bias): Patient discomfort

High risk

Anaesthetist not blinded

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Low risk

Assessed by blinded observer

Blinding of outcome assessment (detection bias): Complications

Low risk

Assessed by blinded observer

Blinding of outcome assessment (detection bias): time outcomes

Low risk

Assessed by blinded observer

Blinding of outcome assessment (detection bias): Patient discomfort

High risk

Assessed by blinded observer, but participant aware of group allocation

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No apparent losses

Selective reporting (reporting bias)

Unclear risk

Published protocol not sought

Baseline characteristics

Low risk

Largely equivalent

Funding sources

Low risk

From departmental sources only

Operator expertise

Unclear risk

Anaesthetists reported as having substantial experience in regional anaesthesia ‐ however, does not specify if experience is equivalent for both techniques. No details of which anaesthetist worked with which group

Methods

RCT, parallel design

Participants

70 participants, ASA I ‐ III scheduled for hallux vagus correction

Excluded: patient refusal to procedure, neurologic or neuromuscular disease, acquired or congenital coagulopathy, skin infection at needle insertion site.

Interventions

Ultrasound + nerve stimulation (n = 35) versus nerve stimulation (n = 35)

Popliteal block of tibial and peroneal nerve; 20 ml LA (10 mL 0.75% ropivacaine and 10 mL 2% lidocaine without epinephrine) ‐ 12 ml close to tibial nerve, 8 ml close to peroneal nerve

Ultrasound: 7.5 ‐ 12 Mhz linear probe; nerve stimulator turned on to confirm correct identification of nerves, then switched off for remaining procedure; endpoint ‐ stimulating current increased to obtain motor response

Nerve stimulation (Stimuplex): pulse duration 100 µsec, initial current density 1 mA, frequency 2 Hz; endpoint ‐ stimulation at < 0.4 mA

Outcomes

1. Adequacy of block (defined as loss of ice sensation after LA injection and confirmed by pain absence at surgical incision or intraoperatively)

2. Complications (puncture of popliteal artery)

3. Block onset time (defined as time interval between end of LA administration and onset of sensory block of peroneal and tibial nerve in its distribution territory)

4. Time to perform block

5. Number of block attempts

6. Participant satisfaction

Notes

All participants first given metatarsal osteotomy with ankle tourniquet.

Blocks performed by 2 resident anaesthetists with prior experience of regional anaesthesia using nerve stimulator, but novices to ultrasound and to popliteal block

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Unclear risk

Randomized using sealed envelopes.  No further details given

Allocation concealment (selection bias)

Unclear risk

No details

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetists

Blinding of participants and personnel (performance bias):Complications

High risk

Not possible to blind anaesthetists

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetists

Blinding of participants and personnel (performance bias): Patient discomfort

High risk

Not possible to blind anaesthetists

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Low risk

Sensory block assessed by a blinded investigator

Blinding of outcome assessment (detection bias): time outcomes

Low risk

Block performance time registered by senior staff not blinded to procedure, but blinded observer monitored onset and progression of sensory block

Blinding of outcome assessment (detection bias): Patient discomfort

Unclear risk

Blinded observer collected participant satisfaction levels in post‐op period, but unclear if participant blinded to group allocation

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No apparent losses

Selective reporting (reporting bias)

Unclear risk

Published protocol not sought

Baseline characteristics

Low risk

Largely comparable. More women than men, but expected for this surgery

Funding sources

Low risk

No funding

Operator expertise

High risk

Anaesthetists had more experience in nerve stimulation use than ultrasound but none had experience of popliteal block

Methods

RCT, parallel design

Participants

188 patients, ASA I ‐ III, scheduled for hand surgery
Exclusion criteria: local anaesthetic allergy, local infection, coagulopathy, neurological upper limb disorder, psychiatric or cognitive disorder, history of substance abuse or opiate use

Interventions

Ultrasound (n = 64) versus ultrasound + nerve stimulation (n = 62) versus nerve stimulation (n = 62)

Axillary brachial plexus block; 3 nerves targeted individually in each group (radial, ulnar, median); all groups received 21 ml 2% lidocaine with 1:200,000 epinephrine and 21 ml 0.5% bupivacaine (14 ml around each nerve)

Ultrasound: linear 5 ‐ 12 MHz probe (Philips HDI 5000); endpoint ‐ local anaesthetic spread around each nerve
Nerve stimulation (Stimuplex): pulse duration 0.1 msec, frequency 2 MHz; endpoint ‐ stimulation at < 0.5 mA
Ultrasound + nerve stimulation: needle positioned with ultrasound, further needle positioning to obtain stimulation at < 0.5 mA; endpoint ‐ circumferential spread of local anaesthetic

Outcomes

1. Block procedure time (time from palpation of axillary artery/ultrasound application to end of LA injection)

2. Adequacy of block (sensory block evaluated in each nerve distribution area using pinprick at 30 min)

3. Supplementation (requirement for either general anaesthesia or rescue block)

4. Complications

Notes

Multiple practitioners ‐ experience in technique not given, although some anaesthetists and some fellow/resident anaesthetists who were supervised

Registered in clinicaltrials.gov

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Computer‐generated random number table

Allocation concealment (selection bias)

Unclear risk

Sealed envelopes, but no further details

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias):Complications

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): Patient discomfort

High risk

Not possible to blind anaesthetist, although use of "sham" equipment in order to ensure participant blinding

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

High risk

Need for rescue block assessed by anaesthetist who was not blinded

Blinding of outcome assessment (detection bias): Complications

Unclear risk

No details of who assessed this, possibly anaesthetist

Blinding of outcome assessment (detection bias): time outcomes

Unclear risk

Assessed by an independent observer, although unclear whether blinded

Blinding of outcome assessment (detection bias): Patient discomfort

Low risk

Assessed during follow‐up telephone conversation ‐ participant blinded to group allocation

Incomplete outcome data (attrition bias)
All outcomes

High risk

30 participants (14%) not included as surgery commenced before 30‐minute assessment. Still possible to collect some outcome data for these participants

Selective reporting (reporting bias)

Low risk

Protocol details published in clinicaltrials.gov. NCT 00221884. Outcomes appear to be reported

Baseline characteristics

Low risk

Age, gender, weight, height, BMI, surgical time. All comparable

Funding sources

High risk

Funding sources reported, to include supply of ultrasound equipment by manufacturers

Operator expertise

High risk

Some blocks performed by supervised residents, which would have increased time to perform block and would introduce bias for this outcome

Methods

RCT, parallel design

Participants

40 participants, ASA I ‐ II scheduled for elective hand surgery under brachial plexus block.

Excluded: Absolute contraindication of regional block, diabetes mellitus, or any other neurological disorder of the upper extremity

Interventions

Ultrasound (n = 20) versus nerve stimulation (n = 20)

Axillary brachial plexus block of radial, ulnar and median nerves; blocked with 40 ml 0.5% ropivacaine

Ultrasound: 5 – 10 MHz linear probe (SonoAce 8000 SE); endpoint ‐ LA solution injected around each of the terminal branches of brachial plexus (median, ulnar and radial), 20 ml 0.5% ropivacaine in region of radial nerve, 10 ml ulnar, 10 ml median

Nerve stimulation (Stimuplex): motor response to a current < 0.5 mA and > 0.2 mA

Participants sedated with propofol TCI 1 ‐ 1.5 ng/ml

Outcomes

1. Supplementation rate (when 50 ‐ 100 µg fentanyl necessary to guarantee analgesia; or when conversion to GA required)

2. Complications (vascular puncture, paraesthesia)

3. Time to perform block (from palpation of axillary artery/ from transducer placed on the skin)

4. Participant discomfort

Notes

No details given of number of practitioners and their experience

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Electronically‐generated random numbers

Allocation concealment (selection bias)

Unclear risk

No details

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias):Complications

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): Patient discomfort

High risk

Not possible to blind anaesthetist

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Unclear risk

No details of who assessed outcomes

Blinding of outcome assessment (detection bias): Complications

Unclear risk

No details of who assessed outcomes

Blinding of outcome assessment (detection bias): time outcomes

Unclear risk

No details of who assessed outcomes

Blinding of outcome assessment (detection bias): Patient discomfort

Unclear risk

No details of who assessed outcomes

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No apparent losses

Selective reporting (reporting bias)

Unclear risk

Published protocol not sought

Baseline characteristics

Low risk

Comparable

Funding sources

Low risk

No funding sources reported

Operator expertise

Unclear risk

No details given of practitioners and levels of experience

Methods

RCT, parallel design

Participants

50 participants, ASA I ‐ III, scheduled for elective coracoacromial ligament repair

Excluded: < 18 yrs, > 85 yrs, unable to express informed consent, with known allergy to study medications, chronic opioid use, ipsilateral upper limb neurological deficits, or contraindications to continuous block placement

Interventions

Ultrasound versus nerve stimulation.

Interscalene brachial plexus block for nerve roots of brachial plexus; blocked with 20 ml 1% lidocaine

Ultrasound: 10 – 12 MHz linear probe (LOGIQ E), in‐plane approach; endpoint ‐ direct visualization of LA spread around nerve roots. Catheter inserted after injection of LA

Nerve stimulation: pulse duration 0.2 ms, initial current 1 mA, frequency 2 Hz; endpoint ‐ stimulation of deltoid muscle motor responses at 0.5 mA. Stimulating perineural catheter was then inserted through the needle and advanced to maintain the adequate motor response at ≤ 0.4 mA.  LA injected in increments

Outcomes

1. Supplementation rate

2. Complications

3. Block onset time (given separately for axillary, radial and musculocutaneous nerves)

4. Time to perform block ("time interval between first US scan and needle removal at end of block in Group US and as the time interval between identification of anatomical landmarks and needle removal at the end of the block in Group NS")

5. Number of block attempts (skin punctures defined as any new needle insertion through the skin; needle redirections defined as any needle withdrawal with subsequent forward movement of 10mm)

6. Participant discomfort

Notes

2 practitioners experienced in both techniques

Registered in clinicaltrials.gov

No numerical data presented for supplementation rate ‐ "There were no differences in the...requirements for GA"

No denominator figures provided. Email request sent to authors, but as yet no reply.

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Computer‐generated sequence of random numbers

Allocation concealment (selection bias)

Unclear risk

“sealed envelope technique” but no further details given

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias):Complications

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): Patient discomfort

High risk

Not possible to blind anaesthetist

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Unclear risk

No details of who assessed this outcome

Blinding of outcome assessment (detection bias): Complications

Unclear risk

No details of who assessed this outcome

Blinding of outcome assessment (detection bias): time outcomes

Unclear risk

Some outcomes recorded by a nurse, but no details as to whether nurse was blinded

Blinding of outcome assessment (detection bias): Patient discomfort

Unclear risk

No details of whether participant blinded to group allocation

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No apparent losses

Selective reporting (reporting bias)

Low risk

Protocol details published in clinicaltrials.gov. NCT 00702416. Outcomes appear to be reported

Baseline characteristics

Low risk

Comparable

Funding sources

Low risk

None apparent

Operator expertise

Unclear risk

Only 2 practitioners, both experienced in both techniques

Methods

RCT, parallel design

Participants

67 participants, ASA I ‐ III, for elective hand surgery
Exclusion criteria: allergy to local anaesthetic; coagulopathy; known neurological deficits; pregnancy;
congestive heart failure; scarring or infection at injection site

Interventions

Continous infraclavicular block (catheter) with ultrasound guidance + nerve stimulation (n = 23) versus nerve stimulation (catheter not stimulated) (n = 22) versus nerve stimulation with stimulation of catheter (n = 22)

Ultrasound: 5 ‐ 10 MHz linear probe (Sonosite titan); position confirmed with nerve stimulation and agitated dextrose; catheter position confirmed visually with agitated dextrose
Nerve stimulation (Pajunk): pulse width 0.1 msec; frequency 2 Hz; starting current 0.5 mA; endpoint 0.2 mA; catheter position not confirmed
Nerve stimulation + stimulating catheter: as for nerve stimulation; catheter position confirmed with nerve stimulation aiming for posterior cord stimulation

Outcomes

1. Supplementation rate ("if surgical anaesthesia was not achieved at the end of 30min, patients either had a rescue block or were given general anaesthesia")

2. Time to perform block (divided into time to locate plexus, time to insert catheter, time to inject LA)

3. Adequacy of block (evaluated every 5 min for 30 min in 5 main nerves)

4. Complications

5. Duration of block

6. Success of re‐establishing block with cathete

Notes

For analysis, we combined the 2 nerve stimulation groups and compared them against the ultrasound group

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Unclear risk

No details given

Allocation concealment (selection bias)

Unclear risk

Closed envelopes used; no further details

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias):Complications

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

High risk

Outcome assessment not blinded “the same anesthesiologist performed and evaluated
the block”

Blinding of outcome assessment (detection bias): Complications

High risk

Outcome assessment not blinded “the same anesthesiologist performed and evaluated
the block”

Blinding of outcome assessment (detection bias): time outcomes

High risk

Outcome assessment not blinded “the same anesthesiologist performed and evaluated
the block”

Incomplete outcome data (attrition bias)
All outcomes

Low risk

2 participants excluded from analysis and details given. Low attrition rate

Selective reporting (reporting bias)

Unclear risk

Published protocol not sought

Baseline characteristics

Unclear risk

Age, height, weight, gender, ASA status. Significantly older participants in group with nerve stimulator with stimulating catheter.

Funding sources

Low risk

None apparent

Operator expertise

Unclear risk

No details

Methods

RCT, parallel design

Participants

61 patients, ASA I ‐ III scheduled foot or ankle surgery
Exclusions: contra‐indication to regional anaesthesia, pre‐existing neuropathy

Interventions

Ultrasound + nerve stimulation (n = 30) versus nerve stimulation (n = 31)

Midfemoral sciatic nerve block with 35 ml 0.5% ropivacaine in both groups

Ultrasound: 7.5 ‐ 11 MHz linear probe (Toshiba Aplio); neurostimulation commenced when needle near nerve; endpoint ‐ neurostimulation at 0.5 mA
Nerve stimulation(Stimuplex): pulse duration 300 msec, frequency 2 Hz; endpoint ‐ stimulation at 0.5 mA

Outcomes

1. Time taken to perform block (time from first needle insertion/beginning of ultrasound technique to successful nerve location)

2. Block onset time (reported separately for superficial peroneal, deep peroneal and tibial)

3. Number of attempts to locate nerve

4. Adequacy of block ("assessed by pinprick method")

5. Supplementation rate ("After 1hr from anesthetic administration, if the sensory block involving the surgical area was considered inadequate...patients received spinal anesthesia")

6. Participant discomfort

7. Postoperative analgesia duration

8. Complications

Notes

1 radiologist and one anaesthetist for all blocks. Experience in technique not given

Additional saphenous nerve block given as required for tourniquet pain

Time to perform block and onset time presented as median (range) and therefore not possible to combine in this review

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Computer‐generated random number

Allocation concealment (selection bias)

Unclear risk

No details given

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias):Complications

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): Patient discomfort

High risk

Not possible to blind anaesthetist

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Unclear risk

No details of who assessed this outcome

Blinding of outcome assessment (detection bias): Complications

Unclear risk

No details of who assessed this outcome

Blinding of outcome assessment (detection bias): time outcomes

Low risk

Quality of nerve block assessed by anaesthetist unaware of group allocation, but no details for other outcomes

Blinding of outcome assessment (detection bias): Patient discomfort

Unclear risk

No details

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No apparent losses

Selective reporting (reporting bias)

Unclear risk

Published protocol not sought

Baseline characteristics

Unclear risk

Some differences in types of surgery between groups

Funding sources

Low risk

No apparent external funding

Operator expertise

Unclear risk

Same anaesthetist performed both blocks

Methods

RCT, parallel design

Participants

51 patients, ASA I ‐ II, scheduled for foot surgery

Exclusion criteria: type I and type II diabetes; history of abnormal bleeding; laboratory evidence of abnormal coagulation; infection at injection site; central or peripheral neurological disease; muscular disease

Interventions

Ultrasound + nerve stimulation (n = 26) versus nerve stimulation (n = 25)

Popliteal sciatic nerve block of tibial and common popliteal nerve with 20 ml 0.5% bupivacaine in both groups (10 ml tibial nerve; 10 ml common popliteal nerve)

Ultrasound: 5 ‐ 10 MHz linear probe (GE LOGIQ book); endpoint ‐ neurostimulation < 0.5 mA; spread of local anaesthetic observed but no repositioning of needle to aid spread permitted

Neurostimulation: pulse duration 0.1 msec; frequency 1 Hz; starting current 1.5 mA; endpoint‐ stimulation < 0.5 mA

Outcomes

1. Adequacy of block (defined as complete sensory and motor block at 30 min)

2. Supplementation rate (required sedation with propofol)

3. Number of needle passes (defined as sum of forward movements of needle preceded by slight withdrawal)

4. Time to perform block (interval between the first needle insertion and its removal at end of the block)

5. Complications (paraesthesia)

6. Participant discomfort

Notes

Participants withdrawn from study if block not completed within 7 min

Additional saphenous nerve block performed to prevent tourniquet pain

1 practitioner performed all US blocks while another performed all control blocks

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Random number table

Allocation concealment (selection bias)

Unclear risk

No details

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias):Complications

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): Patient discomfort

High risk

Not possible to blind anaesthetist

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Low risk

Evaluation of block by independent blinded observer

Blinding of outcome assessment (detection bias): Complications

Unclear risk

No details of who assessed complications at consultation 2 ‐ 4 weeks post‐surgery

Blinding of outcome assessment (detection bias): time outcomes

Low risk

Evaluation of sensory nerve block done by independent observer

Blinding of outcome assessment (detection bias): Patient discomfort

High risk

Participants not blinded to group allocation

Incomplete outcome data (attrition bias)
All outcomes

High risk

High number of exclusions, although details provided

Selective reporting (reporting bias)

Unclear risk

Published protocol not sought

Baseline characteristics

Unclear risk

Some differences in ASA status, with twice as many ASAII participants in ultrasound group

Funding sources

Low risk

None apparent

Operator expertise

High risk

Different anaesthetists performed each block

Methods

RCT, parallel design

Participants

112 ASA I ‐ II participants scheduled for surgery on distal upper limb

Exclusion criteria: poor general health, contraindications to regional anaesthesia

Interventions

Ultrasound (n = 56) versus nerve stimulation (n = 56)

Axillary brachial plexus block with single injection 50 ml 1% mepivacaine in both groups

Ultrasound: 8 ‐ 13 MHz linear probe (Vivid i, Fa. GE); out‐of‐plane approach;

Nerve stimulation (Stimuplex): pulse duration ≥ 0.1 msec; frequency 1 Hz; starting current not stated

Outcomes

1. Adequacy of block

2. Block requiring supplementation or conversion to GA

3. Time to perform block

Notes

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Computer‐generated random numbers

Allocation concealment (selection bias)

Unclear risk

Use of sealed envelope. No further details

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist to procedure technique

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist to procedure technique

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Unclear risk

No details

Blinding of outcome assessment (detection bias): time outcomes

Unclear risk

No details

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No apparent losses

Selective reporting (reporting bias)

Unclear risk

Published protocol not sought

Baseline characteristics

Unclear risk

More women than men in the US group, but described as no difference by authors

Funding sources

Low risk

Assume none

Operator expertise

Unclear risk

No details

Methods

RCT, parallel design

Participants

80 ASA I or II patients, scheduled for hand, wrist and forearm surgery

Excluded: Patients who could not co‐operate, those with disease that could prevent sensory block assessment in upper extremity, patients with coagulopathy, allergy to study drugs, known pregnancy or patients whose pervious surgery or trauma prevented anatomic localization of injection point

Interventions

Ultrasound + nerve stimulation (n = 40) versus nerve stimulation (n = 40)

Infraclavicular brachial plexus block of median, ulnar and radial nerves with 20 ml levobupivacaine, 5 mg/ml and 20 ml of lidocaine and 20 mg/ml with 5 µg/ml epinephrine (total vol 40 ml)

Ultrasound: US probe (GE Logic) (8 ‐ 13 MHz) placed below clavicle about 0.5 ‐ 1 cm inferior to site of needle entry. After identification of axillary artery and cords, stimulating needle was positioned posterior to axillary artery. Electrical stimulator used to obtain motor response distal to elbow (ulnar, median or radial nerve responses). Needle repositioned if necessary to get motor response, then LA injected dorsal to axillary artery. LA distribution around cords and axillary artery observed with US

Nerve stimulation (Stimuplex): 22 G, 100 mm insulated needle connected to negative pole of the nerve stimulator and set to deliver 1.5 mA current impulses of 0.1 ms duration at a frequency of 2 Hz.

Outcomes

1. Adequacy of block (assessed as good, satisfactory or poor at 30 min)

2. Suppplementation rate (required to supplement with LA, or conversion to GA)

3. Time to perform block (no definition)

4. Complications

Notes

Specialist anaesthesiologist and single senior resident. Experienced in block procedure. Does not indicate if experienced in US technique

Results for onset time presented as median (range), therefore not possible to combine for this review. No difference between the 2 groups for this outcome.

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Unclear risk

Described as randomized but no further details given

Allocation concealment (selection bias)

Unclear risk

“sealed envelope technique” – no further details.

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetists

Blinding of participants and personnel (performance bias):Complications

High risk

Not possible to blind anaesthetists

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetists

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Low risk

Assessed by a blinded anaesthetist.

Blinding of outcome assessment (detection bias): Complications

Low risk

Assessed by a blinded anaesthetist.

Blinding of outcome assessment (detection bias): time outcomes

Low risk

No details given as to who measured time to perform block. Possibly blinded anaesthetist?

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No apparent losses to follow‐up

Selective reporting (reporting bias)

Unclear risk

Published protocol sought

Baseline characteristics

Low risk

Mostly comparable

Funding sources

High risk

US device provided by General Electrics Company

Operator expertise

Unclear risk

Not clear if anaesthetists experienced in ultrasound techniques

Methods

RCT, parallel design

Participants

160 patients, ASA I ‐ II for scheduled trauma surgery of shoulder or upper arm

Exclusion criteria: allergy to local anaesthetic; pre‐existing respiratory, metabolic or neurological diseases; history of cardiac, hepatic or renal failure; pregnancy

Interventions

Ultrasound guidance (n = 80) versus nerve stimulation (n = 80)

Interscalene brachial plexus block with 20 ml 0.75% bupivacaine in both groups

Ultrasound: 5 ‐ 10 MHz linear probe (Sonosite); endpoint ‐ visualized spread local anaesthetic around all nerve roots (C5 ‐ T1), multiple injections permitted

Nerve stimulation: pulse duration 0.1 msec, frequency 2 Hz; endpoint ‐ stimulation hand or forearm < 0.5 mA; single injection

Outcomes

1. Supplementation rate ("partially or completely failed blocks" requiring GA)

2. Adequacy of block (defined as "surgical anaesthesia" and assessed pinprick testing)

3. Block onset time

4. Duration of block (time until first analgesia)

Notes

All blocks performed by same 3 anaesthetists with experience in both guidance techniques

Results for onset time given as median (range) therefore not possible to combine for this review

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

External preparation

Allocation concealment (selection bias)

Low risk

Sealed opaque sequentially‐numbered envelopes

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias):Complications

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Unclear risk

Evaluation of nerve block by independent anaesthetist; no details if assessor is blinded

Blinding of outcome assessment (detection bias): Complications

Unclear risk

No details of who assessed this outcome

Blinding of outcome assessment (detection bias): time outcomes

Unclear risk

Evaluation of nerve block by independent anaesthetist; no details if assessor is blinded

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No apparent losses

Selective reporting (reporting bias)

Unclear risk

Published protocol not sought

Baseline characteristics

Low risk

baseline characteristics comparable

Funding sources

Low risk

No apparent external funding

Operator expertise

Unclear risk

All blocks by same experienced anaesthetists

Methods

RCT, parallel design

Participants

90 patients, ASA I ‐ II, scheduled for forearm, wrist or hand surgery
Exclusions: patient refusal, allergy to local anaesthetics, pre‐existing neuropathy, dementia

Interventions

Ultrasound (double injection) (n = 30) versus ultrasound (single injection) (n = 30) versus nerve stimulation (double injection) (n = 30)

Axillary brachial plexus block with 0.5 ml/kg 1.5% lignocaine with epinephrine (5 µg/kg) in nerve stimulation group and 30 ml 1.5% lignocaine with epinephrine (5 µg/kg) in ultrasound groups

Ultrasound: 12 MHz probe (Hawk model 2102, B‐K medical); endpoint ‐ visualization of local anaesthetic spread around axillary artery. Either 1 injection (superior to artery) or 2 injections (superior and inferior to artery)
Nerve stimulation (Stimuplex): 2 Hz; endpoint ‐ stimulation of median nerve and radial nerve. No current thresholds given

Outcomes

1. Time taken to perform block ("from needle puncture on the skin guided by nerve stimulator or the application of the ultrasound on the skin to the completion of the lidocaine injection")

2. Adequacy of block (defined as "loss of pinprick sensation", evaluated at 40 min after injection)

3. Block supplementation ("Anesthetic failure was managed with supplemental intravenous analgesics or general anesthetics as appropriate")

4. Complications

Notes

1 practitioner performed all blocks, experience not given

For the purpose of analysis of Adequacy of block and Supplementation rate, we combined the data for the double and single injection ultrasound groups

For the purpose of analysis of Time to perform block, we took data only from ultrasound (double injection) versus nerve stimulation (double injection)

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Randomization table

Allocation concealment (selection bias)

Unclear risk

No details

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias):Complications

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Low risk

Assessment done by anaesthetist unaware of group allocation

Blinding of outcome assessment (detection bias): Complications

Low risk

Assessment done by anaesthetist unaware of group allocation

Blinding of outcome assessment (detection bias): time outcomes

Low risk

Assessment done by anaesthetist unaware of group allocation

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No withdrawals or exclusions

Selective reporting (reporting bias)

Unclear risk

Published protocol not sought

Baseline characteristics

Low risk

Baseline characteristics comparable

Funding sources

Low risk

No apparent external funding

Operator expertise

Unclear risk

Same anaesthetist for all blocks

Methods

RCT, parallel design

Participants

230 patients, scheduled to undergo outpatient shoulder arthroscopy under interscalene block

Excluded: < 18 yrs, > 75 yrs, patient refusal, pregnancy, dementia, severe pulmonary disease, and known pre‐existing neurological disorders involving the operative limb

Interventions

Ultrasound (n = 115) vs nerve stimulation group (n = 115)

Interscalene block of axillary, musculocutaneous, ulnar, radial and median nerves with mepivacaine 1.5% with 1:300,000 epinephrine and NaCO3 (1 meq/10mL); for participants < 50 kg, total dose of 45 ‐ 55 ml was used

for patients ≥ 50 kg, total dose of 55 ‐ 65 mL was used

Ultrasound: A linear 10 ‐ 13 MHz US probe was used to visualize the brachial plexus. Initial US visualization was at interscalene area.

5 cm 22 G needle placed through middle scalene muscle, into interscalene groove, in‐plane US guidance to visualize the entire needle. LA injected in divided doses with frequent aspiration under ultrasound visualization.

Nerve stimulation (Stimuplex): 5 cm 22 G insulated needle placed into interscalene groove. Current decreased to range between 0.2 mA and 0.5 mA. If not still present then needle adjusted. LA injected in divided doses with frequent aspiration

Outcomes

1. Supplementation rate ("required conversion to general anaesthesia")

2. Time to perform block

3. Number of needle passes

4. Complications

Notes

No details of experience of anaesthetists giving nerve blocks

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Computer‐generated random number table

Allocation concealment (selection bias)

Unclear risk

Used a “sealed envelope sequence”. No further details

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias):Complications

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Low risk

Adequacy of block assessed by an investigator who was unaware of group allocation

Blinding of outcome assessment (detection bias): Complications

Low risk

Neurological complications assessed and analyzed by blinded investigator

Blinding of outcome assessment (detection bias): time outcomes

Unclear risk

Time to perform block assessed by an investigator not performing block but no details as to whether they were blinded

Incomplete outcome data (attrition bias)
All outcomes

Low risk

Some losses to follow‐up but relatively small number and details given

Selective reporting (reporting bias)

Unclear risk

Pre‐published protocol not sought

Baseline characteristics

Low risk

All comparable

Funding sources

Low risk

None apparent

Operator expertise

Unclear risk

No details of who, how many and experience of anaesthetists giving blocks

Methods

RCT, parallel design

Participants

60 patients undergoing elective endoscopic carpal tunnel release

Exclusions: none stated

Interventions

Ultrasound (n = 30) versus nerve stimulation (n = 29)

Median and ulnar nerve block (at wrist) with 4 ml 1.5% mepivacaine injected around each nerve in both groups

Ultrasound: 13 MHz linear probe (GE LOGIQ e); endpoint ‐ local anaesthetic spread around each nerve. Needle repositioning to allow adequate spread

Nerve stimulation (HNS 12, B Braun): pulse duration 0.1 msec; Freq 2 Hz; endpoint ‐ stimulation < 0.5 mA motor or sensory response

Outcomes

1. Block performance time (from start of locating nerve to end of local anaesthetic injection)

2. Onset time of block (data reported separately for median and ulnar nerve)

3. Adequacy of block ("sensory loss assessed by cold testing")

4. Supplementation rate (depending on scores for cold testing after 600 seconds, could be considered a failed block, and complementary block using ultrasound guidance was performed)

5. Pain during block

6. Block performance (assessed on visual analogue scale)

Notes

Palmaris radius blocked blindly in both groups

Author contact attempted in original review for additional information for risk of bias table

No details of experience of anaesthetist giving block

Data for Block Performance time and Onset time presented as median (interquartile range), so not possible to combine in this review

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Unclear risk

Described as randomized but no details given

Allocation concealment (selection bias)

Unclear risk

No details

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): Patient discomfort

High risk

Not possible to blind anaesthetist

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Unclear risk

Sensory loss assessed by investigator not involved in block performance, but no details of whether blinded

Blinding of outcome assessment (detection bias): time outcomes

Unclear risk

No details of who assessed this outcome

Blinding of outcome assessment (detection bias): Patient discomfort

High risk

No details of whether participants blinded to group allocation, assume not blinded

Incomplete outcome data (attrition bias)
All outcomes

Low risk

Only 1 withdrawal due to protocol violation ‐ low attrition rate

Selective reporting (reporting bias)

Unclear risk

Published protocol not sought

Baseline characteristics

Low risk

Baseline characteristics largely equivalent

Funding sources

Low risk

No apparent funding sources

Operator expertise

Unclear risk

No details

Methods

RCT, parallel design

Participants

60 patients, ASA I ‐ II, scheduled for hand, forearm and elbow surgery

Exlusion criteria: ASA > III, < 18 years and > 85 years, general contraindications for plexus block, known muscular or neurological deficits, pregnant or breastfeeding women, comprehension difficulties

Interventions

Ultrasound (n = 30) versus nerve stimulation (n = 30)

Axillary plexus block of median, radial, musculocutaneous, and ulnar nerve with 40 ‐ 50 ml 1.5% mepivacaine (plexus) and 5 ‐ 10 ml mepivacaine 0.5% (subcutaneous in medial skin of arm)

Ultrasound: no details in paper

Nerve stimulation (Braun): pulse duration 0.1 msec. Endpoint ‐ visible muscle contractions at current of 0.3 ‐ 0.5 mA

Outcomes

1. Adequacy of block

2. Supplementation rate (participants given 'rescue' block, supplementary fentanyl or GA)

3. Complications

4. Performance time

5. Onset time (data presented as overall time for motor block and overall time for sensory block)

Notes

5 practitioners with more than 5 years experience

Participants given tourniquet block in both groups

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Randomization table

Allocation concealment (selection bias)

Unclear risk

Insufficient details

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias):Complications

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): Patient discomfort

High risk

Not possible to blind anaesthetist

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Low risk

Assessor blinded from group allocation

Blinding of outcome assessment (detection bias): Complications

Low risk

Assessor blinded from group allocation

Blinding of outcome assessment (detection bias): time outcomes

Low risk

Assessor blinded from group allocation

Blinding of outcome assessment (detection bias): Patient discomfort

Low risk

Assessor blinded from group allocation

Incomplete outcome data (attrition bias)
All outcomes

Low risk

Only 2 losses, clearly explained

Selective reporting (reporting bias)

Unclear risk

Published protocol not sought

Baseline characteristics

Low risk

Age, gender, BMI, type of surgery, time length of surgery. All comparable

Funding sources

Low risk

None

Operator expertise

Unclear risk

5 practitioners with more than 5 years experience

Methods

RCT, parallel design

Participants

129 ASA I ‐ II patients scheduled for elective orthopaedic surgery of elbow, forearm, wrist or finger

Exclusion criteria: patient refusal, neurological disturbance, infection/inflammation of the upper extremity, coagulopathy, inability to communicate, those expected to have an axillary catheter

Interventions

Ultrasound with nerve stimulation (n = 65) versus nerve stimulation only (n = 62)

Axillary brachial plexus block of median, musculocutaneous, cubital and radial nerve

Each nerve blocked with 10 ml 1% mepivacaine (40 ml in total) in each group

Ultrasound: 5 ‐ 10 MHz linear probe (Titan, Sonosite) out‐of‐plane approach, once brachial plexus structures seen nerve stimulator used

Nerve stimulation (Stimuplex): pulse duration 0.3 msec, Freq 2 Hz; endpoint ‐ stimulation of motor response at 0.4 mA

Outcomes

1. Adequacy of motor and sensory block (defined as those given only nerve block)

2. Supplementation rate (need for sedation)

3. Time to perform block

Notes

2 anaesthesiologists with extensive experience in both techniques

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Use of random number table

Allocation concealment (selection bias)

Unclear risk

No details given

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Unclear risk

No details of who assessed outcomes

Blinding of outcome assessment (detection bias): time outcomes

Unclear risk

No details of who assessed outcomes

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No apparent losses

Selective reporting (reporting bias)

Unclear risk

Published protocol not sought

Baseline characteristics

Low risk

Age, gender, weight, height, ASA status reported. All comparable

Funding sources

Low risk

None apparent

Operator expertise

Unclear risk

Two anaesthesiologists with extensive experience in both techniques

Methods

RCT, parallel design

Participants

70 patients, ASA I ‐ II, scheduled for elective foot and ankle surgery

Exclusions: contraindication to nerve block; significant peripheral neuropathy or neurological disease affecting lower extremity; pregnancy; history of alcohol or drug abuse; long‐standing opiate intake; significant psychiatric conditions

Interventions

Ultrasound guidance (n = 37) versus nerve stimulation (n = 33)

Popliteal fossa sciatic nerve block with 30 ml local anaesthetic mixture in both groups (15 ml 2% lignocaine and 15 ml 0.5% bupivacaine)

Ultrasound: 4 ‐ 7 MHz or 4 ‐ 8 MHz linear probe (Philips Ultrasound); endpoint ‐ local anaesthetic spread around nerve; needle position adjustment permitted (Note: current required to elicit motor stimulation recorded once needle positioned with ultrasound but no further needle adjustment)

Nerve stimulation (Stimuplex): duration 0.1 msec; frequency 2 Hz; endpoint ‐ stimulation of foot or toes at < 0.5 mA

Outcomes

1. Block procedure time (from ultrasound preparation/start of landmark palpation until completion of LA injection)

2. Adequacy of block (assessed by loss of pinprick sensation after 30 min)

3. Supplementation rate ("Anesthesiologist...had discretion to induce a general anesthetic if blockade was incomplete and not deemed sufficient for surgical anesthesia")

4. Complications

Notes

Saphenous nerve block also given if required, for tourniquet pain

Registered in clinicaltrials.gov

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Computer‐generated random number

Allocation concealment (selection bias)

Low risk

"group allocation not disclosed to patients" ‐ but no details given

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias):Complications

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): Patient discomfort

Low risk

Sham ultrasound used, although relevant participant outcomes not reported

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Low risk

Investigator blinded to group allocation assessed progress of block

Blinding of outcome assessment (detection bias): Complications

Low risk

Blinded anaesthetist responsible for all intraoperative care including induction of GA

Blinding of outcome assessment (detection bias): time outcomes

Low risk

Investigator blinded to group allocation assessed progress of block

Incomplete outcome data (attrition bias)
All outcomes

Low risk

4 participants excluded but low attrition rate

Selective reporting (reporting bias)

Low risk

Protocol details published in clinicaltrials.gov. NCT 00221920. Outcomes appear to be reported

Baseline characteristics

Low risk

Baseline characteristics largely comparable, although some differences in gender ratios

Funding sources

Low risk

Funding from university research award

Operator expertise

Unclear risk

Experienced anaesthetists in both techniques

Methods

RCT, parallel design

Participants

60 patients, ASA I ‐ III, scheduled for elbow, forearm, wrist and hand surgery under supraclavicular brachial plexus block without sedation

Excluded: Patients refusing supraclavicular block, inability to obtain informed consent, hemidiaphragmatic dysfunction, coagulation disorders, neuropathy, pulmonary and cardiac disorders, BMI 35 kg/m² or higher, pregnancy, allergy to LA

Interventions

Ultrasound (n = 30) vs neurostimulation (n = 30)

Supraclavicular brachial plexus block of ulnar, median, radial and musculocutaneous nerves with 20 ml 0.75% ropivacaine

Ultrasound: 38 mm 6 ‐ 13 MHz broadband linear array US probe to identify brachial plexus in short‐axis view located lateral to the subclavian artery. In‐plane approach

Nerve stimulation (HNS 11, B. Braun):pulse duration 0.1 msec, frequency 2 Hz. Endpoint: Flexion of both fingers and wrist or extension of fingers at a stimulation current between 0.20 and 0.50 mA

Outcomes

1. Supplementation rate (need for intraoperative intravenous fentanyl due to pain; or supplementation of local anaesthetic or GA)

2. Adequacy of block (defined as "absent sensation in the sensory distribution of all ...nerves"

3. Diaphragmatic movements assessed by ultrasonography for presence of hemidiaphragmatic paresis

Notes

For Supplementation rate we took data for intravenous fentanyl administration only. There were no participants requiring local anaesthetic or GA.

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Computer‐generated sequence of random numbers

Allocation concealment (selection bias)

Unclear risk

Sealed envelopes. No further details

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Unclear risk

No details of who assessed this and whether blinded

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No apparent losses after randomization

Selective reporting (reporting bias)

Unclear risk

Prepublished protocol not sought

Baseline characteristics

Low risk

Largely comparable

Funding sources

Low risk

None; department funding only

Operator expertise

Unclear risk

No details given of who gave anaesthetic and level of expertise

Methods

RCT, parallel design

Participants

60 patients scheduled for shoulder surgery

Excluded: Hypersensitivity to local anaesthetics, neurologic deficits, bleeding tendency, respiratory failure, local infection, refusal to participate in the study or request for GA

Interventions

Ultrasound + nerve stimulation (n = 30) vs nerve stimulation alone (n = 30)

Interscalene brachial plexus block; In both cases, 30 ml of prilocaine was used followed by catheter insertion

Ultrasound: Roots of brachial plexus sought between anterior and middle scalene muscles in an axial oblique plane. After sonographic plexus identification, injected glucose 5% to scan fluid around the plexus, then fixed needle. Nerve stimulation then switched on looking for muscle contractions as below

Nerve stimulation (Stimuplex): pulse duration 0.1 msec, frequency 2 Hz, initial current mA. 5 ml sytrine with NaCl 0.9% through injection line inserted in a caudal slightly lateral and discrete dorsal orientation

After 3 ‐ 4 cm, biceps contractions and then current reduced incrementally until 0.2 ‐ 0.3 mA was reached. Then needle retracted slightly and LA slowly injected

Outcomes

1. Adequacy of block (assessed using cold alcohol spray as complete)

2. Supplementation rate (required additional anaesthesia)

3. Time to perform block ("mean time spent detecting brachial plexus and injecting the LA")

4. Onset time of block

Notes

Study published in journal's 'short communication', therefore limited details

Results for onset time presented as median and range, not possible to combine in this review. No statistically significant difference reported for this outcome

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Unclear risk

Not specified

Allocation concealment (selection bias)

Unclear risk

Not specified

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Unclear risk

No details of who assessed this outcome and whether blinded

Blinding of outcome assessment (detection bias): time outcomes

Unclear risk

No details of who assessed this outcome and whether blinded

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No apparent losses

Selective reporting (reporting bias)

Unclear risk

Published protocol not sought

Baseline characteristics

Low risk

Comparable

Funding sources

Low risk

None apparent

Operator expertise

Unclear risk

2 anaesthetic consultants with "over 10 years experience"

Methods

RCT, parallel design

Participants

80 patients, ASA I ‐ II, scheduled for elective forearm or hand surgery

Exclusions: not detailed (inclusion criteria: ASA I or II; weight 50 ‐ 100 kg; normal neurological status; co‐operative)

Interventions

Ultrasound (n = 40) versus peripheral nerve stimulation (n = 40)

Interscalene brachial plexus block of musculocutaneous, radial, median, ulnar and antebrachial cutaneous nerves with 0.6 ml/kg mepivacaine with epinephrine in both groups

Ultrasound: 5 ‐ 8 MHz curved probe (Sonosite); endpoint ‐ spread local anaesthetic around all cords or spread from 3 o'clock to 11 o'clock around artery. Multiple injections permitted

Nerve stimulation (Stimuplex): 0.1 msec duration, frequency 2 Hz; starting current 1.5 mA; endpoint ‐ motor response in finger or hand from posterior or middle cord at 0.2 ‐ 0.5 mA. Single injection

Outcomes

1. Supplementation rate (need for local anaesthetic block supplementation, sedatives/analgesics, or GA)

2. Adequacy of block (assessed with sensory testing of all 5 nerves. "Block sufficient for surgery")

3. Block onset time

4. Block performance time (from needle insertion until finishing LA injection; in ultrasound group also included "prescan time")

5. Complications

6. Number of attempts (needle passes defined as withdrawal and subsequent reinsertion of at least 2 cm)

7. Participant discomfort

Notes

Registered in clinicaltrials.gov

Data for block performance time not presented as mean (SD) and therefore not possible to combine in this review

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Random numbers; permuted blocks

Allocation concealment (selection bias)

Unclear risk

Sealed envelopes opened immediately before block performed. No additional details

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias):Complications

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): Patient discomfort

High risk

Not possible to blind anaesthetist

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Low risk

Assessed by blinded observer

Blinding of outcome assessment (detection bias): Complications

Unclear risk

Unclear who assessed this outcome and whether blinded

Blinding of outcome assessment (detection bias): time outcomes

Unclear risk

No details of who assessed these outcomes and whether blinded

Blinding of outcome assessment (detection bias): Patient discomfort

High risk

Participant not blinded to group allocation

Incomplete outcome data (attrition bias)
All outcomes

Low risk

Only 1 loss, low attrition rate

Selective reporting (reporting bias)

Low risk

Protocol details published in clinicaltrials.gov. NCT 00321425. Outcomes appear to be reported

Baseline characteristics

Low risk

Baseline characteristics comparable

Funding sources

Low risk

None apparent

Operator expertise

Unclear risk

2 anaesthetists experienced in both techniques

Methods

Randomized, parallel design

Participants

250 ASA I ‐ III adult patients scheduled for orthopaedic foot surgery under tourniquet

Exclusion criteria not given

Interventions

Ultrasound (n = 125) versus nerve stimulation (n = 125);

Distal sciatic block of sciatic, tibial and common peroneal nerves; each nerve blocked with 20 ml 1% prilocaine and 10 ml 0.75% ropivacaine

Ultrasound: 6 ‐ 13 MHz linear probe (Sonosite); intraepineural needle position

Nerve stimulation (Stimuplex): 0.1 msec duration, frequency 2 Hz; starting current 1.0 mA

Outcomes

1. Block requiring supplementation or conversion to GA

2. Block onset time

Notes

Saphenous nerve block for tourniquet pain given to all participants

Registered in clinicaltrials.gov

Data for block onset time presented as log‐rank test results and therefore not possible to combine for this review Reported as significantly shorter onset time in US group, P value < 0.01

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Computer‐generated list

Allocation concealment (selection bias)

Unclear risk

No details

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Low risk

Observer blinded from group allocation

Blinding of outcome assessment (detection bias): time outcomes

Low risk

Observer blinded from group allocation

Incomplete outcome data (attrition bias)
All outcomes

Low risk

7 participants in each group excluded from analysis, but low attrition rate

Selective reporting (reporting bias)

Low risk

Protocol details published in clinicaltrials.gov. NCT 01643616. Outcomes appear to be reported

Baseline characteristics

Low risk

Age, weight, height, gender, surgery time, diabetes mellitis. Some difference in gender balance but otherwise all comparable

Funding sources

Low risk

No conflicts of interest or funding declared

Operator expertise

Unclear risk

No details

Methods

RCT, parallel design

Participants

70 adult patients ASA I and II requiring upper arm surgery (wrist, forearm and hand) under axillary block

Exclusion criteria: History of coagulopathy, allergy to drug, diabetes, local infection at site of block, patients requiring bilateral hand surgery, patients’ denial, cases that needed conversion to GA, surgery lasting more than 3.5 hours and patients beyond age of 20 ‐ 65 yrs, and body weight of 45 ‐ 65 kg

Interventions

Ultrasound + nerve stimulation (n = 35) versus nerve stimulation (n = 35)

Axillary brachial plexus block for ulnar, radial, median and musculocutaneous nerves

Nerves blocked with a total of 24 ml of bupivacaine 0.5% with injection dexamethasone 4 mg, each individual nerve blocked with 6 ml

Ultrasound: 8 MHz linear probe (Toshiba); endpoint ‐ nerve location confirmed by nerve stimulation and then local anaesthetic deposited under ultrasound guidance

Nerve stimulation (Stimuplex): 0.2 msec duration, frequency 2 Hz; starting current 1.0 mA. Current reduced to 0.6 mA then 1 ml of LA injected to see if twitches disappeared. Then remaining 5 ml given

Outcomes

1. Supplementation rate (reported as participants who had a successful block, defined as not requiring rescue blocks or drug supplements. For this review analysis, data converted to fit our outcome definition)

2. Complications

3. Onset time (reported separately for sensory and motor block)

4. Time to perform block (no definition provided)

5. Number of attempts

Notes

1 anaesthetist performed all blocks, but no details of their experience in the 2 techniques

Results for onset time reported as statistically significant difference between groups with shorter onset time in US group, P value < 0.01

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Use of a “lottery method”

Allocation concealment (selection bias)

Unclear risk

No details

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias):Complications

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Low risk

Data recorded by blinded observer

Blinding of outcome assessment (detection bias): Complications

Low risk

Data recorded by blinded observer

Blinding of outcome assessment (detection bias): time outcomes

Low risk

Data recorded by blinded observer

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No apparent losses

Selective reporting (reporting bias)

Unclear risk

Published protocol not sought

Baseline characteristics

Low risk

All comparable

Funding sources

Low risk

None apparent

Operator expertise

Unclear risk

Only 1 person performing all blocks

Methods

RCT, parallel design

Participants

56 patients, ASA I ‐ III, scheduled for hand surgery
Exclusions: < 18 years, pregnant, allergy to study drug

Interventions

Ultrasound perivascular approach (n = 28) versus transarterial approach (n = 28)

Axillary brachial plexus block with 30 ml 1.5% lidocaine in both groups

Ultrasound: 3 ‐ 12 MHz probe (Philips EnVisor); endpoint ‐ circumferential spread of local anaesthetic around artery
Transarterial: local anaesthetic injected when no blood aspirated on either side of artery

Separate musculocutaneous nerve block could be done at discretion of operator prior to study protocol (uncontrolled)

Outcomes

1. Block failure

2. Time to perform block (time from completion of sterile preparation to withdrawal of needle)

3. Supplementation rates (conversion to GA, supplementation or rescue block)

4. Adequacy of block (sensory testing evaluated with ice bag in palm

5. Neurological complications

Notes

7 practitioners performing blocks (3 trainees and 4 experienced)

Musculocutaneous nerve block not controlled for and used at anaesthetist's preference

5 ml 1.5% lidocaine with 5 µg/ml epinephrine given to all participants for analgesia for tourniquet pain

Study terminated early due to high level of block failure in transarterial group

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Use of block randomization

Allocation concealment (selection bias)

Unclear risk

Sealed envelopes but no further details

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias):Complications

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist/personnel

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Low risk

Block assessed by blinded observer. Upgrade to GA etc. made by anaesthetist or surgeon not aware of group allocation

Blinding of outcome assessment (detection bias): Complications

Unclear risk

No details of who assessed this outcome

Blinding of outcome assessment (detection bias): time outcomes

Low risk

Blinded research nurse

Incomplete outcome data (attrition bias)
All outcomes

High risk

Trial stopped early due to high failure rate in transarterial group

Selective reporting (reporting bias)

Unclear risk

Outcomes reported despite early stopping. Published protocol not sought

Baseline characteristics

Low risk

Baseline characteristics comparable

Funding sources

High risk

Ultrasound equipment provided by manufacturer during trial

Operator expertise

High risk

Some blocks performed by a supervised resident, some by an experienced anaesthetist

Methods

RCT, parallel design

Participants

40 patients for elective upper limb surgery
Interscalene block for shoulder surgery (24 participants) and axillary plexus block for hand surgery (16 participants)

Exclusion criteria: pre‐existing neurological deficit, local sepsis, respiratory failure, patient refusal

Interventions

Ultrasound (n = 20) versus landmark technique (n = 20)

Interscalene or axillary brachial plexus block with 3 mg/kg ropivacaine (0.75% for interscalene; 0.6% for axillary)

Ultrasound: 13 MHz probe (Siemens sonoline); endpoint ‐ local anaesthetic spread around individual nerves/trunks. Needle position altered during injection to optimize local anaesthetic spread
Landmark: needle positioned by landmark palpation, paraesthesia not purposely sought.

Outcomes

1. Supplementation rate (requirement for conversion to GA)

2. Adequacy of block (sensory block assessed by response to ice)

3. Complication rate

4. Participant satisfaction

5. Pain scores (recovery and 12 hours)

6. Block duration

Notes

1 practitioner performed all blocks. Previous experience in ultrasound blocks and tuition from radiologist

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Unclear risk

Details not given

Allocation concealment (selection bias)

Unclear risk

Details not given

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias):Complications

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Unclear risk

Assessments done by independent investigator but no details of whether they were blinded.

Blinding of outcome assessment (detection bias): Complications

Unclear risk

No details of who assessed this and whether blinded to group allocation

Blinding of outcome assessment (detection bias): time outcomes

Unclear risk

No details of who assessed this and whether blinded to group allocation

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No apparent losses

Selective reporting (reporting bias)

Unclear risk

Published protocol not sought

Baseline characteristics

Unclear risk

No standard baseline characteristics reported

Funding sources

Low risk

No apparent additional funding sources

Operator expertise

Unclear risk

Same operator performed all blocks

Methods

RCT, parallel design

Participants

141 patients scheduled for hand surgery distal to the elbow with and estimated duration < 2 hrs

Excluded: Those that declined to give informed consent, had known allergy to any anaesthetic substance, an infection in region of injection site, severe coagulopathy, pathological enlargement of axillary lymph nodes, those who had had previous surgery on the axilla

Interventions

Ultrasound (n = 70) vs landmark technique (n = 71)

Axillary brachial plexus block; dose of 20 ml LA deposited behind artery next to radial nerve; 10 ml LA then injected around mediocranial median nerve and mediocaudal ulnar nerve

Ultrasound: cross‐section of axillary artery is imaged. Individual nerves are then identified. Cannula introduced under US. 20 G 105” bevelled needle. LA injected around all 4 nerves individually starting with radial nerve. Aim of infiltration is to see a circular perineural spread of the fluid in the ultrasound image. Bupivacaine hydrochloride (5 mg/ml) with 0.5% adrenaline and mepivacaine hydrochloride (10 mg/ml) in a ratio of 1:1

Neurostimulation: Anatomic landmarks used for orientation. Needle inserted in space between axillary artery and coracobrachial muscle, near to axillary fold. Needle at an angle to skin of 50 ‐ 90°, inserted past facial click and advanced cranially, caudally or transarterially past axillary artery

Outcomes

1. Supplementation rate (blocks which required additional anaesthesia, analgesics or GA)

2. Complications

3. Time to perform block (no definition)

Notes

Training had been given to those conducting the ultrasound technique; baseline of 10 procedures with US before study, or 300 in conventional technique

Not possible to combine data for Time to perform block or Onset time as no standard deviation reported

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Computer‐generated random numbers

Allocation concealment (selection bias)

Unclear risk

No details

Blinding of participants and personnel (performance bias):Complications

High risk

Surgeon not blinded

Blinding of participants and personnel (performance bias): time outcomes

High risk

Surgeon not blinded

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

High risk

“No blinding” reported at end of discussion

Blinding of outcome assessment (detection bias): Complications

High risk

“No blinding” reported at end of discussion

Blinding of outcome assessment (detection bias): time outcomes

High risk

“No blinding” reported at end of discussion

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No apparent losses

Selective reporting (reporting bias)

Unclear risk

Published protocol not sought

Baseline characteristics

Low risk

All comparable

Funding sources

Low risk

None

Operator expertise

High risk

Surgeon with limited experience (10 previous attempts) using ultrasound technique

Methods

RCT, parallel design

Participants

70 ASA I ‐ III patients scheduled for hand/wrist surgery

Exclusion criteria: Patient refusal, neurologic or neuromuscular disease, anticoagulation, skin infection at site of needle insertion

Interventions

Ultrasound (n = 35) versus nerve stimulation (n = 35)

Coracoid infraclavicular brachial plexus block with single injection of 40 ml mepivacaine 1.5%

Ultrasound: probe 6 ‐ 13 MHz (MicroMaxx); endpoint ‐ visualization under US of spread of local anaesthetic posterior to axillary artery

Nerve stimulation (Pajunk Medizintechnologic): 0.1 msec duration, frequency 2 Hz; starting current 1.5 mA

Current decreased to 0.5 mA or less when radial nerve stimulation could still be elicited. Then LA injected slowly

Outcomes

1. Adequacy of block (defined as "complete sensory and motor block associated with a pain‐free surgery")

2. Supplementation rate (required intraoperative fentanyl supplementation or supplemental peripheral nerve block/GA)

3. Complications

4. Onset time (complete sensory and motor block)

5. Time to perform block (time between needle insertion and its removal at end of LA injection).

Notes

2 practitioners performing blocks with long‐standing experience in performance of both nerve stimulator and US coracoid infraclavicular brachial plexus blocks

Block considered a failure if taken more than 15 minutes to perform

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Unclear risk

Computer‐generated random list

Allocation concealment (selection bias)

Unclear risk

No details

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Anaesthetist not blinded

Blinding of participants and personnel (performance bias):Complications

High risk

Anaesthetist not blinded

Blinding of participants and personnel (performance bias): time outcomes

High risk

Anaesthetist not blinded

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Unclear risk

No details of who assessed this outcome – assume anaesthetists?

Blinding of outcome assessment (detection bias): Complications

Low risk

Assessed by an independent observer not aware of technique

Blinding of outcome assessment (detection bias): time outcomes

Low risk

Assessed by an independent observer not aware of technique

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No apparent losses

Selective reporting (reporting bias)

Unclear risk

Prepublished protocol not sought

Baseline characteristics

Low risk

Some differences in type of surgery but unlikely to introduce bias, otherwise all comparable

Funding sources

Low risk

None

Operator expertise

Unclear risk

2 experienced anaesthetists

Methods

RCT, parallel design

Participants

60 ASA I ‐ II patients scheduled for surgery of the upper limb (wrist, hand, elbow or distal arm)

Exclusion criteria: none

Interventions

Ultrasound (n = 30) versus nerve stimulation (n = 30)

Infraclavicular brachial plexus block; nerves blocked with 15 ml 0.5% bupivacaine

Ultrasound: 10 ‐ 12 MHz linear probe (Logiq 7) in‐plane approach; endpoint ‐ visualized LA injection around each brachial plexus cord with approximately 5 ml

Nerve stimulation (Stimuplex): Initial stimulating current at 1 ‐ 1.5 mA; endpoint ‐ current gradually decreased until responses still present at 0.3 mA or less

Outcomes

1. Adequacy of block (defined as "complete sensory and motor block ...until 30 minutes after performing the block allowing for surgery, for all nerves")

2. Onset time of block

3. Procedure time

Notes

Surgical tourniquet used in all participants

Note: supplementary GA was used at discretion of attending anaesthetist and was not reported as an outcome. However, all participants were described as being awake during surgery

Data for onset time of block reported as median (IQR), therefore not possible to combine in analysis. Onset time for motor block in US group 20 min (15 ‐ 26) vs 23 min (16 ‐ 32) in NS group; onset time for sensory block in US group 10 min (10 ‐ 15) vs 14 min (12 ‐ 25) in NS group

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Unclear risk

Randomized by "distributing sealed, opaque envelopes". No further details

Allocation concealment (selection bias)

Unclear risk

As above. No further details

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Low risk

Assessed by anaesthetist blinded to technique used

Blinding of outcome assessment (detection bias): time outcomes

Unclear risk

Assessed by anaesthetist blinded to technique used

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No apparent losses

Selective reporting (reporting bias)

Unclear risk

Published protocol not sought

Baseline characteristics

Low risk

Age, gender, ASA status, weight, height, BMI, surgical duration. All comparable.

Funding sources

Low risk

None apparent

Operator expertise

Unclear risk

No details given

Methods

RCT, parallel design

Participants

40 ASA I ‐ III patients undergoing surgery of foot or ankle with distal sciatic nerve block in popliteal fossa

Exclusion criteria: Patient refusal, pre‐existing neuropathy, kidney or liver disease, pregnancy, skin infection at site of needle insertion and inability to communicate

Interventions

Ultrasound (n = 20) versus nerve stimulation (n = 20)

Distal sciatic nerve block in the popliteal fossa with lignocaine 1.5% with adrenaline 5 µg/ml – at discretion of anaesthetist, min of 25 ml and max of 40 ml

Ultrasound: with 7 ‐ 13 MHz 38 mm linear probe (Sonosite); endpoint ‐ visualization of LA distribution around nerve

Nerve stimulation (HNS 11, Braun): 0.1 msec duration, frequency 2 Hz; starting current 1.0 mA. Initial current reduced until responses maintained with minimum of 0.2 mA and max 0.5 mA

Outcomes

1. Adequacy of block (defined as "surgical block success")

2. Block performance time (interval between first needle insertion and its removal at end of injection of local anaesthetic)

3. Number of attempts

4. Pain during puncture

Notes

Anaesthetists had extensive clinical experience with nerve stimulation guided popliteal sciatic nerve blocks but no experience with ultrasound guidance block

Some participants also given saphenous nerve block if tourniquet required for surgery; no details in results of those that were given additional block

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Unclear risk

Described as randomized using sealed envelopes. No further detail

Allocation concealment (selection bias)

Unclear risk

No details

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Anaesthestists not blinded

Blinding of participants and personnel (performance bias): time outcomes

High risk

Anaesthestists not blinded

Blinding of participants and personnel (performance bias): Patient discomfort

High risk

Anaesthestists not blinded

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Unclear risk

No details of who assessed this. Assume anaesthetist?

Blinding of outcome assessment (detection bias): time outcomes

Low risk

Assessor blinded to block technique

Blinding of outcome assessment (detection bias): Patient discomfort

Low risk

Assessor blinded to block technique

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No apparent losses

Selective reporting (reporting bias)

Unclear risk

Published protocol not sought

Baseline characteristics

Low risk

Age, weight, height, ASAI‐III, gender, type of surgery. All comparable

Funding sources

High risk

Funding from dept sources. Study equipment supported was provided from Sonosite Inc, Bothell, WA, USA

Operator expertise

High risk

Anaesthetists had extensive clinical experience with nerve stimulation guided popliteal sciatic nerve blocks but no experience with ultrasound guidance block

Methods

RCT, parallel design

Participants

80 patients undergoing distal arm, forearm or hand surgery
Exclusions: coagulopathy, infection at injection site, allergy to local anaesthetics, severe pulmonary pathology, age < 18, language barriers, mental incapacity, BMI > 35, pre‐existing weakness or loss of sensation in operative limb

Interventions

Ultrasound + nerve stimulation (n = 40) versus nerve stimulation (n = 40)

Supraclavicular brachial plexus block with 0.5 ml/kg of 0.5% bupivacaine/2% lidocaine and 1:200,000 epinephrine to maximum of 40 ml

Ultrasound: 7.5 MHz probe (Aloka); endpoint ‐ neurostimulation at < 0.6 mA
Neurostimulation: endpoint ‐ neurostimulation at < 0.6 mA

Outcomes

1. Adequacy of block (defined as proportion of blocks in which surgical anaesthesia was achieved)

2. Supplementation rate (need for supplementation or general anaesthesia)

3. Complications (incidence or neurological or respiratory complications; follow‐up until discharge, then at 1 week)

4. Time to perform block (interval between first needle insertion and its removal at end of block)

5. Time until first analgesia request

Notes

All blocks attempted by 1 anesthesiology resident (limited experience of both techniques)
Help obtained by senior anaesthetist if block not performed within 20 min

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Unclear risk

Described as randomized but no further details

Allocation concealment (selection bias)

Unclear risk

No details

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias):Complications

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias): time outcomes

High risk

Not possible to blind anaesthetist

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Unclear risk

No details given of who assessed outcomes and whether blinded

Blinding of outcome assessment (detection bias): Complications

Unclear risk

No details given of who assessed outcomes and whether blinded

Blinding of outcome assessment (detection bias): time outcomes

Unclear risk

No details given of who assessed outcomes and whether blinded

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No losses

Selective reporting (reporting bias)

Unclear risk

Published protocol not sought

Baseline characteristics

Low risk

Baseline characteristics comparable

Funding sources

Low risk

No apparent funding

Operator expertise

High risk

Performed by anesthesiology resident who had experience of blocks whilst under supervision by staff anaesthesiologist. This may have increased time to perform block and would introduce bias for this outcome

Methods

RCT, parallel design

Participants

34 adult ASA 1 ‐ III patients scheduled for surgery of upper limb

Exclusions: Allergy to local anaesthetic, coagulopathy, infection at site of injection, pre‐existing neurological lesion

Interventions

Ultrasound (n = 17) versus nerve stimulation (n = 17)

Posterior approach to brachial plexus block of axillary, musculocutaneous, radial and median nerves; single injection of 30 ml 0.325% ropivacaine

Ultrasound: 6 ‐ 13 mHz., cervical nerve root identified as a hypoechoic, circular image. Endpoint ‐ visualization of distribution of LA around nerve

Nerve stimulation (Stimuplex): 0.1 msec duration, frequency 2 Hz; starting current 0.8 mA. Endpoint ‐ not stated

Outcomes

1. Adequacy of block (evaluated by response to cold at 10, 20 and 30 min)

2. Dysphonia

Notes

No details of experience of practitioners given

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Unclear risk

No details given

Allocation concealment (selection bias)

Unclear risk

No details given

Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation

High risk

Not possible to blind anaesthetist

Blinding of participants and personnel (performance bias):Complications

High risk

Not possible to blind anaesthetist

Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block

Unclear risk

No details given

Blinding of outcome assessment (detection bias): Complications

Unclear risk

No details given

Incomplete outcome data (attrition bias)
All outcomes

Low risk

No apparent losses

Selective reporting (reporting bias)

Unclear risk

Postoperative pain outcomes not reported. Published protocol not sought

Baseline characteristics

Low risk

Some differences in gender between groups, otherwise comparable

Funding sources

Low risk

No details. Assume no funding from external sources.

Operator expertise

Unclear risk

No details