Bioengineered nerve conduits and wraps for peripheral nerve repair of the upper limb
Appendices
Appendix 1. Types of Outcome Measurement
Outcome measurements that currently prevail in the literature are British Medical Research Council (BMRC) motor and sensory grading system, Semmes Weinstein Monofilament (SWM) test and static or moving two‐point discrimination (s/m2PD). Neurophysiological and magnetic resonance imaging (MRI) assessment modalities are not routinely employed in the postoperative period at present. The Rosén Model Instrument is becoming increasingly recognised as a comprehensive assessment tool of integrated function, but is yet to be adopted throughout the literature. Ideally, following peripheral nerve surgery a holistic evaluation of outcome would be made. This would be performed at regular and defined postoperative periods and comprise of an objective, sensitive analysis of integrative function (e.g. The Model Instrument, Rosén 2000), accurate biodynamic outcome analysis (Pruszynski 2014) or vibrotactile perception (Dahlin 2015). Combined with participant‐reported outcome measurements investigating the individual’s perception of performance over a series of tasks, this would allow more detailed evaluation. Currently resource limitations and clinical practicalities necessitate the pragmatic use of less rigorous measurements of outcome in most studies.
The BMRC Motor Grade assesses motor function on a six‐point scale, with ability to overcome gravity and comparison to the contralateral limb providing important benchmarks.
| BMRC Motor Grade | Muscle Strength |
| M0 | No movement is observed |
| M1 | Trace or flicker of movement or fasciculations seen |
| M2 | Muscle can exert movement when gravity is eliminated |
| M3 | Muscle can exert movement against gravity |
| M4 | Muscle strength is reduced but some movement against resistance |
| M5 | Normal movement |
The BMRC sensory grade (Zachary 1954), assesses sensory recovery on a seven‐point scale, where S0 is absence of any sensory recovery and S4 is recovery of sensibility and two‐point discrimination of 3 mm to 6mm (S2 and S3 are further subdivided into S2+ and S3+). Weighted pins (e.g. 5 g to10g) may be used for testing pressure and pain, Von Frey's hairs are used to assess tactile sensation; these are available in various calibres, and a two‐point discrimination is assessed with a fine calliper. The sensory scale will be interpreted critically and detailed methodology provided.
| BMRC Sensory Grade | Sensory Recovery |
| S0 | Absence of sensibility in the autonomous area |
| S1 | Recovery of deep cutaneous pain sensibility |
| S2 | Return of some degree of some degree of superficial cutaneous pain and tactile sensibility within the autonomous area of the nerve |
| S3 | Return of some degree of some degree of superficial cutaneous pain and tactile sensibility within the autonomous area of the nerve with disappearance of any previous over reactivity |
| S3+ | Return of sensibility as in Stage 3 with the addition that there is recovery of two‐point discrimination within the autonomous area |
| S4 | Complete recovery |
The Model Instrument is one of the most well recognised and widely applied composite assessment tools for assessment of peripheral nerve function following repair at the distal forearm and wrist (Rosén 2000). This standardised tool correlates well with the Disability of the Arm Shoulder and Hand (DASH), a validated participant‐reported outcome measurement of perceived ability to carry out activities of daily living (Beaton 2001; Gummesson 2003). A detailed protocol of the components of the test has been published, allowing inter‐operator standardisation. Briefly, a quantitative assessment of:
‐ Motor recovery ‐ manual muscle testing and Jamar® dynamometer to test motor innervation and grip strength)
‐ Sensory recovery ‐ Semmes Weinstein Monofilaments (SWM) are used to assess touch/pressure thresholds, two‐point discrimination (2PD)
‐ Tactile gnosis and dexterity ‐ shape texture identification (STI) to assess as well as three selected tasks from the Sollerman grip test (Sollerman 1995)
‐Pain/discomfort ‐ four‐point scale questionnaire focusing on cold sensitivity, hyperaesthesia and allodynia is performed.
The score for each subtest is normalised by dividing by a “normal” result – this may be pre‐determined or obtained by testing the uninjured, contralateral arm. The mean score is calculated for each domain and the sum of these three scores generates the overall score which is plotted against 'average results' and over time. This allows recording of functional recovery and a prediction of recovery, by comparison to values generated in participants with similar injuries ('average results'). As the Rosén method encompasses a spectrum of tests it requires availability of assessment tools, experienced staff and protected time periods to conduct. This ideally would form part of ongoing routine assessment by a dedicated and experienced hand surgery team, unfortunately this limits its use in some settings. As such, although desirable, lack of this reporting outcome will not be used as exclusion criteria.
Appendix 2. MEDLINE (OvidSP) draft search strategy
Database: Ovid MEDLINE(R) <1946 to February Week 2 2016>
Search Strategy:
‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐
1 randomised controlled trial.pt. (406217)
2 controlled clinical trial.pt. (90055)
3 randomized.ab. (303442)
4 placebo.ab. (155007)
5 clinical trials as topic.sh. (174864)
6 randomly.ab. (214885)
7 trial.ti. (131755)
8 exp Cohort Studies/ (1493921)
9 cohort*1.tw. (297767)
10 or/1‐9 (2349178)
11 exp animals/ not humans.sh. (4187037)
12 10 not 11 (2248669)
13 (nerve adj2 (wrap* or cuff* or repair* or graft* or allograft* or autograft*)).mp. (5629)
14 13 or conduit*1.mp. (21783)
15 (upper limb* or arm*1 or upper extremit*).mp. (175831)
16 exp upper extremity/ (142589)
17 15 or 16 (276373)
18 Peripheral Nerve Injuries/ (5016)
19 12 and 14 and 17 and 18 (61)
20 remove duplicates from 19 (61)
