Decellularized Nerves for Upper Limb Nerve Reconstruction: A Systematic Review of Functional Outcomes

This is a systematic review for evaluating the evidence for functional outcomes after decellularized nerve use in clinical setting. Decellularized nerves are allografts whose antigenic components have been removed, leaving only a scaffold that promotes the full regeneration of axons.

Literature research was performed using the PubMed/MEDLINE database for English language studies with the keywords "decellularized nerve" and "processed nerve allograft." Inclusion criteria were prospective and retrospective case reviews in clinical settings. Exclusion criteria were case reports and case series.

We retrieved six level VIII studies and one level VI study (classified according to the Jovell and Navarro-Rubio scale) with a total of 131 reconstructions. The basic data ranges of the studies were as follows: patient age, 18 to 86 years; duration between initial injury and nerve reconstruction procedure, 8 hours to 4 years; and follow-up period, 40 days to 2 years. The maximum lengths of the nerve gap for chemically washed decellularized nerves and cryopreserved decellularized nerves were 50 and 100 mm, respectively. Quantitatively, the functional outcome ranges were as follows: static two-point discrimination, 3 to 5 mm; and moving two-point discrimination, 2 to 15 mm. For motor assessment, all patients had a > M3 Medical Research Council score. It is also important to notice that a large variability occurs in almost every factor in the reviewed studies.

Our study is the first to summarize the clinical results of decellularized nerves. Decellularized nerves have been used to bridge nerve gaps ranging from 5 to 100 mm with associated satisfactory outcomes in static and moving two-point discriminations.