Postoperative meralgia paresthetica after posterior spine surgery: incidence, risk factors, and clinical outcomes.

STUDY DESIGN: A prospective study on postoperative meralgia paresthetica after posterior thoracolumbar spine surgery on the Relton-Hall frame.

OBJECTIVES: To assess the incidence of postoperative lateral femoral cutaneous nerve (LFCN) neuralgia and to investigate its risk factors and clinical outcomes.

SUMMARY OF BACKGROUND DATA: Postoperative meralgia paresthetica is a common complication of posterior thoracolumbar spine surgery. The injury mechanism is external compression to the LFCN near the anterior superior iliac spine in the prone position.

METHODS: A total of 252 patients were examined for signs of meralgia paresthetica before and after surgery. Patients with a LFCN injury were followed regularly until sensory impairment resolved. Several possible contributing factors were assessed to evaluate the correlations.

RESULTS: Postoperative meralgia paresthetica was experienced by 60 patients (23.8%). Patients with an LFCN injury had a significantly greater body mass index (23.6 vs. 22.4 kg/m2) and a longer surgical time (3.7 vs. 3.2 hours). Overweight/obese patients had a significantly greater incidence (odds ratio, 1.83; 95% confidence interval, 1.02-3.29). Patients operated for degenerative spinal disorders also had a significantly higher incidence of LFCN injury (odds ratio, 2.81; 95% confidence interval, 1.53-5.13). Recovery took 10.5 days on average (range, 2 days to 2 months). Thirty-two patients (53%) recovered completely within the first week and every patient recovered within 2 months.

CONCLUSION: Postoperative meralgia paresthetica is a common but benign complication of posterior thoracolumbar spine surgery. Degenerative spinal disorders, overweight/obesity, and longer surgical time are factors related to a higher incidence of LFCN injury. The clinical outcome is always excellent, and complete recovery can be expected within 2 months.