Defects of the sciatic nerve and its divisions treated by direct suturing in 90 degrees knee flexion: report on the first clinical series.

Abstract

To evaluate functional results after treatment of large defects of the sciatic nerve and its divisions by direct nerve suturing in high knee flexion. A retrospective review was conducted in patients treated for lower extremity nerve defects between 2011 and 2019. Inclusion criteria were a defect > 2cm with a minimal follow-up period of 2years for the sciatic nerve and 1year for its divisions. Nerve defects were bridged by an end-to-end suture with the knee flexed at 90° for 6weeks. Functional results were assessed based on the Medical Research Council's grading system. Seventeen patients with a mean age of 27.6years were included. They presented with seven sciatic nerve defects and ten division defects, including eight missile injuries. The mean time to surgery was 12.3weeks and the mean nerve defect length was 5cm. Overall, 21 nerve sutures were performed, with eight in the tibial distribution and 13 in the fibular distribution. Post-operatively, there was no significant knee stiffness related to the immobilization. The mean follow-up time was 24.5months. Meaningful motor and sensory recovery were observed after 7 of 8 sutures in the tibial distribution and 11 of 13 sutures in the fibular distribution. A functional sural triceps muscle with protective sensibility of the sole was restored in all patients. There were no differences according to the injury mechanisms. Temporary knee flexion at 90° allows for direct coaptation of sciatic nerve defects up to 8cm, with promising results no matter the level or mechanism of injury.