Peroneal neuropathy with foot drop after bariatric surgery: A neurosurgical perspective.

OBJECTIVE: Peroneal neuropathy is the most common entrapment neuropathy of the lower extremity and most commonly results from compression of the peroneal nerve at the fibular head. This study aimed to evaluate the relationship between peroneal neuropathy and rapid weight loss after bariatric surgery and to assess the outcomes of surgical decompression in patients presenting with foot drop. METHOD: Between 2020 and 2025, five patients underwent surgical treatment for foot drop due to peroneal neuropathy following bariatric surgery. The diagnosis was confirmed by clinical evaluation, imaging, and electromyography (EMG). Changes in body weight and body mass index before and after bariatric surgery, the duration of weight loss, time to onset of clinical symptoms, and changes in clinical findings after peroneal nerve decompression were evaluated. RESULTS: Of the five patients who developed peroneal neuropathy after bariatric surgery, two were female and three were male. The mean age was 37 years. Compared with preoperative body weight, the mean weight reduction was 36.6%. Patients experienced the greatest weight loss within the first 4-6 months after bariatric surgery. Foot weakness developed a mean of 7.2 months after bariatric surgery. All patients underwent peroneal nerve decompression. At the six-month follow-up, four patients had a Medical Research Council (MRC) score of 5, including one patient with bilateral involvement, whereas one patient had an MRC score of 4. CONCLUSION: Both mechanical and metabolic factors may contribute to the development of peroneal neuropathy after rapid and substantial weight loss. Given the increasing prevalence of obesity, the growing use of bariatric surgery, and changing societal attitudes toward weight loss, clinicians should remain alert to such neurological complications. Early diagnosis and timely surgical intervention may contribute to favorable neurological outcomes.