Lateral Femoral Cutaneous Nerve Palsy After Spinal Fusion for Adolescent Idiopathic Scoliosis (AIS).

Study Design: Prospective study of consecutive patients.
Objective: The purpose of the study was to evaluate the incidence, risk factors, and time to resolution of lateral femoral cutaneous nerve palsy (LFCNP) after posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS).
Summary of Background Data: No prior studies have prospectively evaluated the prevalence of LFCNP exclusively in the treatment of AIS.
Methods: Between June 2014 and May 2015, patients undergoing PSF for AIS were examined preoperatively, postoperatively, and at follow-up clinic visits until the resolution of the LFCNP. All neurologic examinations were performed by attending pediatric orthopedic surgeons. Patients who underwent staged, revision or anterior procedures, had preoperative neurologic deficits or neuropathy, were excluded.
Results: A total of 55 patients with an average age of 14 years (10-21) were enrolled. Twenty-five percent (14/55) of patients had a postoperative LFCNP. There were no other postoperative neurologic deficits. Of the 14 patients with an LFCNP, 57% of these were bilateral. Fourteen percent (2/14) of these patients had absent sensation to light touch, whereas 85% (12/14) had decreased sensation. No patients reported experiencing pain associated with the LFCNP or tenderness when the anterolateral thigh was palpated. The LFCNP did not limit postoperative mobilization or prolong hospital stay. The LFCNP was noted to resolve in an average of 3.6 days (1-18); 6/14 (43%) resolved after 1 day. No correlation was observed between occurrence of LFCNP and sex, age, height, body mass index, length of fusion, Cobb angle, or blood loss. The occurrence of LFCNP was associated with heavier weight (P = 0.032) and longer operative times (P = 0.016). Resolution of the LFCNP was associated with longer operative time (P = 0.010).
Conclusion: LFCNP occurred in 25% of AIS patients undergoing PSF. Risk of LFCNP increased with longer operative times and heavier patient weight. On average, LFCNP resolved in less than 4 days and did not cause any pain or limitations.
Level of Evidence: 2.