Sonographic evaluation of the sciatic nerve in patients with lower-limb amputations

Hypertrophy of the sciatic nerve after lower-limb amputation in patients with sarcomas has been previously reported by magnetic resonance imaging; however, sonographic evaluation of the sciatic nerve after lower-limb amputation due to nonmalignant causes has not been done before. Therefore, the aim of this study was to perform imaging of the sciatic nerve in lower-limb amputees and to find out whether sonographic findings were related to clinical characteristics. Twenty-three males with lower-limb amputations due to traumatic injuries were enrolled. Sonographic evaluations were performed using a linear array probe (Aloka UST-5524-7.5 MHZ). Sciatic nerve diameters were measured bilaterally at the same level, and the values of the normal limbs were taken as controls. Sciatic nerve width and thickness values were found to be greater on the amputated sides than the normal sides (P = 0.001). The thickness values were greater in above-knee amputees than below-knee amputees (P = 0.05). Subjects with a neuroma also had thicker sciatic nerves (P = 0.04). The diameters were found not to change between subjects with different liners (P > 0.05), but they were correlated with time after amputation (r = 0.6, P = 0.006; r = 0.4, P = 0.05, respectively). Our results clearly show that the sciatic nerves were wider and thicker on the amputated sides. Amputation level, duration, and the presence of a neuroma seem to affect the eventual diameters of the nerves.