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Cochrane Database of Systematic Reviews Protocol - Intervention

Infraclavicular brachial plexus block for regional anaesthesia of the lower arm

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Abstract

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:

Our objective is to determine if there is sufficient evidence to recommend the infraclavicular block over other approaches to the brachial plexus when providing regional anaesthesia for surgery of the lower arm. To this end, we will attempt to answer the following question: "Is adequate surgical anaesthesia of the lower arm and hand achieved more frequently, with faster onset, with longer duration of post‐operative analgesia, and with lower frequency of complications using an infraclavicular approach compared to other approaches to the brachial plexus?"

Background

Surgical anaesthesia of the lower arm, from the elbow to the hand, may be readily achieved by local anaesthetic blockade of the bundle of nerves passing from the spinal cord through to the top of the arm (the brachial plexus) (Cousins 1998). This avoids the need for a general anaesthetic and its accompanying risks (airway injuries, postoperative nausea and vomiting, postoperative drowsiness, etc). Control of postoperative pain is also excellent, as the arm remains numb for several hours following blockade of the brachial plexus. The numbness gradually resolves, allowing ample time for the introduction of oral analgesics to control pain. Commonly used approaches include the interscalene block, the supraclavicular block and the axillary block

The brachial plexus can be approached from various points with a needle, and located using surface landmarks and, sometimes, stimulation with a low‐amplitude current. Such stimulation produces tingling, movement, or both, in the part of the arm supplied by any nerve approached closely by the tip of the needle. Commonly used approaches include the interscalene block (where the needle passes between the scalene muscles after piercing the skin in the front of the neck); the supraclavicular block (where the skin is pierced lower and more laterally above the collar bone) and the axillary block (where the skin is pierced in the armpit). More recently, another approach, the infraclavicular block (where the skin is pierced in the area below the collarbone), has enjoyed a resurgence of interest.

Bazy (Bazy 1917) introduced the infraclavicular approach in 1917 as an alternative to the axillary and supraclavicular approaches. However the method failed to gain popularity and remained largely forgotten for several decades. Spiegel (Spiegel 1967) described an infraclavicular technique in 1967, but it was not until 1973, when Raj et al (Raj 1973) described their infraclavicular block, that interest in this approach was re‐ignited. Despite good results it again failed to gain widespread acceptance. This may have been due to a perceived lack of significant advantages over the axillary block, concern over the risk of pneumothorax (a punctured lung), as well as the requirement for a nerve stimulator (which was not widely available at the time). Subsequently, Sims (Sims 1977) published a modification to the Raj approach in 1977, and Whiffler (Whiffler 1981) described the first coracoid block in 1981. However, it was not until Kilka and colleagues (Kilka 1995) described their vertical infraclavicular plexus block in 1995 that interest in the infraclavicular approach really blossomed. Since then, several other variants of the infraclavicular block have been described and adopted into clinical practice (Borgeat 2001; Jandard 2002; Kapral 1999; Minville 2004; Salazar 1999; Wilson 1998).

The infraclavicular region can be visualized as a pyramidal space, containing the brachial plexus, the subclavian‐axillary artery and vein, lymph nodes and loose fatty tissue. The apex is a triangular surface formed by the confluence of the clavicle, scapula and first rib; the base is the skin and subcutaneous tissue of the armpit. The posterior wall is formed by the scapula and its associated muscles; the anterior wall by the pectoralis major and minor, together with their investing fasciae. The humerus, and the converging muscles and tendons of the anterior and posterior walls that insert into it, constitute the lateral wall. The bony thoracic cage, with its overlying layer of serratus anterior muscle and fascia, forms the medial wall. At the level of the infraclavicular space, the brachial plexus is organized as three cords (lateral, medial and posterior) surrounding the axillary artery. None of the major terminal branches arise at this level.

The touted advantages of the infraclavicular approach are as follows. Firstly, it provides comprehensive anaesthesia of the upper limb, equalled only by the supraclavicular approach. The axillary approach often fails to block the axillary nerve and musculocutaneous nerves (which branch off at a higher level), whilst the interscalene and supraclavicular approaches often may fail to provide anaesthesia in the distribution of the ulnar nerve (Cousins 1998). Secondly, unlike the interscalene and supraclavicular approaches, the risk of inadvertent lung or pleural puncture is minimal (Cousins 1998). Thirdly, by piercing the skin below the collarbone, injury to the neurovascular structures in the neck are avoided (unlike the interscalene approach). Finally, it is an ideal site for long‐term brachial plexus blockade. The bulk of the pectoralis muscle firmly anchors the catheter, arm movement is not impaired, and hygiene is easily maintained (Brown 1993).

Given these advantages, the infraclavicular block would appear to be the regional anaesthetic technique of choice for surgery of the lower arm. Whether or not it is indeed a more effective and safer technique for brachial plexus blockade in clinical practice remains to be established.

Objectives

Our objective is to determine if there is sufficient evidence to recommend the infraclavicular block over other approaches to the brachial plexus when providing regional anaesthesia for surgery of the lower arm. To this end, we will attempt to answer the following question: "Is adequate surgical anaesthesia of the lower arm and hand achieved more frequently, with faster onset, with longer duration of post‐operative analgesia, and with lower frequency of complications using an infraclavicular approach compared to other approaches to the brachial plexus?"

Methods

Criteria for considering studies for this review

Types of studies

We will include randomized controlled trials (RCTs)comparing the infraclavicular block with any other regional anaesthetic technique for operative anaesthesia of the lower arm or hand.

Types of participants

We will include all patients undergoing surgery of the lower arm (hand, forearm or elbow, either alone or in combination) under planned regional anaesthesia only. We will exclude patients having a planned combined regional and general anaesthetic, as the efficacy of the regional anaesthetic cannot be assessed if a general anaesthetic is given simultaneously.

Types of interventions

We will accept any RCT that compares the infraclavicular approach to the brachial plexus (as described above), with any alternative techniques to anaesthetize the plexus, including interscalene, supraclavicular or axillary approaches. We will include any variation of these techniques, including:

  1. single shot or continuous catheter techniques;

  2. single or multiple nerve stimulation techniques;

  3. localization of the brachial plexus by any of the following means: surface landmarks, elicitation of paraesthesiae, electro‐stimulation, or ultrasound guidance;

  4. any local anaesthetic agent.

Types of outcome measures

Primary outcomes

Proportion of patients obtaining adequate surgical anaesthesia from the block alone within 30 minutes.

Secondary outcomes
Secondary outcome measures (efficacy)

  1. Proportion of patients requiring supplemental local anaesthetic blocks and systemic analgesia, or both, to achieve adequate surgical anaesthesia.

  2. Proportion of patients requiring general anaesthesia to achieve surgical anaesthesia.

  3. Number of patients complaining of tourniquet discomfort.

  4. Onset time of adequate surgical anaesthesia.

  5. Duration of post‐operative analgesia, measured as the time to first request for additional analgesia. Pain scores will be recorded if available.

  6. Proportion of patients complaining of pain during performance of the block. Pain scores will be recorded if available.

Secondary outcome measures (safety)

  1. Proportion of patients experiencing pneumothorax.

  2. Proportion of patients experiencing vascular puncture, as well as any related sequelae, e.g. haematoma formation, haemorrhage.

  3. Proportion of patients experiencing Horner's syndrome.

  4. Proportion of patients experiencing neurological deficits, including residual neuropraxias unrelated to the surgical site, that last more than 24 hours.

  5. Proportion of patients experiencing systemic complications related to administration of local anaesthetic. These include cardiorespiratory arrest, symptoms of local anaesthetic toxicity or any other events reported by study investigators.

Search methods for identification of studies

We will search the following databases for relevant trials: the Cochrane Anaesthesia Review Group's specialized trial register, the Cochrane Central Register of Controlled Trials (CENTRAL) (current issue of The Cochrane Library); MEDLINE (1966 to date), and EMBASE (1974 to date).

We will attempt to identify all relevant studies regardless of language. We will manually check reference lists of all studies identified for trials missed by the electronic search strategy. We will contact primary authors of identified trials for more information, especially regarding unpublished data.

We will search MEDLINE (1966 to date) via PubMed using the strategy detailed in Appendix 1.We will modify this search strategy as necessary, and apply it to the EMBASE and CENTRAL databases as well.

Data collection and analysis

Selection of trials

Two authors (KJC, VTWC) will independently review the titles and abstracts identified by from the searches. We will obtain full copies of potentially relevant trials and assess all full copies according to the parameters outlined in 'Criteria for considering studies for this review'. Only trials meeting these criteria will be assessed for methodological quality. A third author (BL) will arbitrate and resolve any disagreements in the process.

Assessment of methodological quality.

We will assess trial quality using the criteria developed by the Cochrane Anaesthesia Review Group. These criteria include assessment of allocation bias, treatment bias, observer bias, and attrition bias. The three authors will resolve any disagreements regarding the assessment by discussion and consensus.

Data collection

Two authors (KJC, VTWC) will independently extract data using a form modified from one developed by the Cochrane Anaesthesia Review Group. We will resolve discrepancies by discussion. We will (as far as possible) extract data on the basis of an intention‐to‐treat analysis. We will contact primary investigators for missing data. Two authors (KJC and VTWC) will enter all data independently into Review Manager 4.2. We will check for differences in the data using the Review Manager 4.2 double entry facility.

Data synthesis

We will assess statistical heterogeneity using the I2 statistic and give consideration to the appropriateness of pooling and meta‐analysis. Where appropriate, we will combine the data for the various trials and express the treatment effect as a pooled relative risk and 95% confidence interval (CI) for dichotomous data, and as a mean difference and 95% CI for continuous data. We will use a fixed‐effect model where there is no evidence of significant heterogeneity between studies (I2 less than 40%) and employ a random‐effects model when such heterogeneity is likely (DerSimonian 1986). In cases where study combination is not possible or appropriate, (for example if there is significant clinical heterogeneity), we will provide narrative synthesis. We will perform a sensitivity analysis if methodological quality or baseline characteristics of the patients in the studies differ significantly.

Where appropriate data exist, we will consider a subgroup analysis based on:

  1. the approach to the brachial plexus used in the control group (interscalene, supraclavicular, axillary);

  2. the method used to locate the brachial plexus (paresthesiae, electrostimulation, ultrasound);

  3. the number of separate nerve stimulations elicited (for blocks performed using electrostimulation);

  4. whether a single‐shot or continuous catheter technique was used;

  5. the technique used for the infraclavicular approach;

  6. the volume of local anaesthetic used;

  7. the type of local anaesthetic agent used;

  8. the age of the patient (children versus adults);

  9. the type of surgery performed (vascular, orthopaedic, etc).