Anatomical relationships between the nerve to gracilis and the motor entry points of the quadriceps nerves: a cadaveric study informing obturator to femoral nerve transfers

<title>Abstract</title> <p> Purpose In nerve transfers (NT), positioning the coaptation site close to the target muscle reduces regeneration distance. In obturator to femoral NTs, the nerve to gracilis (NG) and the quadriceps nerves are common donor and recipient nerves, respectively. This study examined whether recipient nerve selection influences how closely a coaptation site could theoretically be positioned relative to the target muscle. Methods Sixteen cadaveric thighs were dissected. NG length and direct pathway distances from the NG origin to each quadriceps nerve motor entry point (MEP) were measured. These measurements were used to estimate how closely a coaptation site could theoretically be positioned relative to each recipient nerve MEP, expressed as the minimum residual distance to the MEP (MRD _MEP ). A linear mixed-effects model and post-hoc pairwise comparisons were used to evaluate differences in MRD _MEP among quadriceps nerves. Results Mean NG length was 68.44 ± 15.78 mm. The estimated marginal mean (EMM) for MRD _MEP for the proximal nerve to the rectus femoris was significantly smaller than most other quadriceps nerves (0.20 mm). Distal nerves to the vastus medialis and vastus lateralis had significantly larger MRD _MEP EMMs relative to other quadriceps nerves (70.50 mm and 55.98 mm, respectively). Conclusion In obturator to femoral NTs, recipient nerve selection may influence how closely a coaptation site can theoretically be positioned relative to the target muscle. Because coaptation site positioning was evaluated theoretically, further studies are needed to determine whether the observed differences in MRD _MEP among recipient nerves translate into clinically meaningful differences in regeneration distance. </p>