Table 2. Randomized controlled trials, systemic reviews and meta-analyses reporting outcomes in the use of autograft, allograft and conduits for digital nerve gaps.
| Author | Type of nerve and gap | No. of repairs | Follow-up | Outcomes | Author’s conclusions |
|---|---|---|---|---|---|
| Randomized controlled trials | |||||
| Weber et al. [2000] (33) | Nerve defects in the hand; average 5 mm gap | 56 AG and DR; 46 PGA conduits | AG and DR 8.1, PGA conduit 9.4 months | M2PD: ≤4 mm gap: PGA 3.7, DR 6.1; 5–7 mm gap: PGA 8.9, DR 6.0; ≥8 mm gap: PGA 6.8, AG 12.9 | PGA conduit better moving sensory recovery than AG for ≥8 and ≤4 mm, but overall no significant differences |
| Bertleff et al. [2005] (36) | Nerve defects in the hand; gap ≤20 mm for all patients | 21 Neurolac (PLCL), 13 DR | 12 months | S2PD and M2PD no difference between both groups | Nerve gaps of up to 20 mm in the hand can be treated with a nerve conduit instead of a nerve graft |
| Calcagnotto and Braga Silva [2006] (37) | Digital nerves, average gap 15 mm | 25 sural nerve graft, 25 vein conduit with interposition of PIN nerve segment | 10.4 months | S2PD and M2PD no difference between both groups | Outcomes were equal in both groups. Both patient age and age of the nerve lesion independently affected results |
| Rinker and Liau [2011] (38) | Digital nerves, average gap 10 mm | 36 PGA conduit, 32 autologous vein conduit | 12 months | S2PD and M2PD no difference between both groups | Sensory recovery was equivalent in both groups with fewer complications noted in autologous vein conduit group |
| Means et al. [2016] (27) | Digital nerves, average gap 12 mm | 6 PNA, 9 hollow conduit | 12 months | MP2D: PNA 5 mm, Hollow conduit 7 mm; S2PD: PNA 5 mm, Hollow conduit 8 mm | PNAs produced more consistent functional sensory outcomes compared with hollow conduits |
| Systemic reviews and meta-analyses | |||||
| Paprottka et al. [2013] (34) | Digital nerves with gap of up to 4 cm | 2,997 nerves: 384 AG, 115 artificial conduit, 102 vein conduit, 56 muscle and muscle in vein reconstructions, 31 ETS repaire, 2 digital artery reconstructions, 924 digital replantation, 1,383 DR | At least 12 months | No difference in sensory outcomes overall. However, DR and AG had slightly more S4 (using the Mackinnon and Dellon sensory scale) than other methods | Authors recommendation for gaps of <10 mm: vein graft or artificial conduit; 10–30 mm: artificial conduit or PIN graft; >30 mm: AG or ETS coaptation |
| Kim et al. [2018] (35) | Digital nerves; average gap 15 mm | 818 nerves, including: 31% nerve graft, 11% synthetic conduits, 10% vein conduit, 35% DR | 22 months | 81% had sensory recovery of S3+/S4 (using the Mackinnon and Dellon sensory scale). Significant better S2PD seen in nerve reconstructions performed within 15 days of injury and defect length of <13 mm | Digital nerve reconstruction provides good to excellent sensory recovery in up to 81% of patients. No significant functional differences across age, follow-up time, injured digit or side, or reconstructive technique |
| Herman and Ilyas [2020] (39) | Digital nerves; average gap: PNA 15.4 mm, AG 24.7 mm, conduit 13.4 mm | 611 nerves analysed for S2PD outcomes: 125 AG, 138 PNA, 90 conduit, 258 DR | 9.4 to 23.2 months | Highest percentage of patients with S2PD ≤6 mm was seen in the autograft group (28%), followed by PNA (23%), conduits (19%) | AG and PNA are comparable, both superior than conduit repair |
| Mauch et al. [2019] (24) | Digital nerves; average gap: AG 22 mm, allograft 13 mm, conduit 12 mm |
70 AG, 66 PNA, 101 conduit, 569 DR | 13 to 42 months | Percentage of patients with sensory recovery of S3+ to S4 (using the British Medical Research Council Sensory Scale) was similar in AGs (88%) and PNAs (86%), compared to conduits (77%) | AG and PNA repairs demonstrated similar rates of normal or near normal sensation. Conduits resulted in a higher rate of incomplete recovery of sensation and complications |
| Braga Silva [2021] (40) | Digital nerves; gaps stratified into subgroups: <5.49, 5.5–10.99, 11–17.99 mm |
961 digital nerves, including: 158 AG, 299 PNA, 114 PGA tubes, 152 collagen tubes, 113 vein graft, 122 DR | 6 and 12 months | Conduits and AGs had no significant differences in S2PD and M2PD outcomes. However, the group with 11–17.99 mm gap had significantly greater improvement in M2PD for AG group compared to conduit | Data insufficient to guide treatment, many studies not able to identify the better treatment due to small sample sizes and low quality evidence |
AG, autograft; DR, direct end-to-end repair; PGA, polyglycolic acid; PLCL, poly(D,L-lactide-co-ε-caprolactone; S2PD, static 2 point discrimination; M2PD, moving 2 point discrimination; PIN, distal posterior interosseous nerve; PNA, processed nerve allograft; ETS, end to side.