Relationship Between Conflict of Interest and Reported Outcomes After Upper Extremity Nerve Reconstruction Using Acellular Nerve Allografts: A Systematic Review.

Abstract

Acellular nerve allografts (ANAs) are increasingly used for peripheral nerve repair. However, the effect of industry sponsorship on reported outcomes remains unclear. This review evaluates functional outcomes following upper extremity nerve reconstruction with ANAs, stratified by conflict of interest (COI). A Preferred Reporting Items for Systematic Reviews and Meta-Analyses-guided search of MEDLINE, PubMed, and Embase identified clinical studies using ANAs. Data extracted included study design, patient age, nerve gap length, outcome measures (Medical Research Council Classification, Disabilities of the Arm, Shoulder, and Hand, visual analog scale), and COI status. Outcomes were compared using independent t-tests. Twenty-eight studies met inclusion criteria. Non-COI studies involved older patients and longer nerve gaps. Motor recovery was markedly higher in COI studies compared with non-COI studies (69.8% vs. 14.1%; P < 0.001), whereas sensory recovery also differed markedly (25.9% vs. 80.4%; P < 0.001). These findings suggest that outcome reporting may be influenced by funding source. The use of subjective measures and study design limitations further complicate objective interpretation. Although ANAs offer promise, current evidence is shaped by sponsorship bias. Future research should prioritize standardized, objective assessments, and independent, prospective studies to guide clinical decision making.