Subclinical neuropathy in diabetic patients: a risk factor for bilateral lower limb neurological deficit following spinal anesthesia?

Total knee arthroplasty performed under spinal or general anesthesia is a common successful orthopedic procedure. Nonetheless, in patients with diabetes mellitus this procedure can present unique challenges to orthopedic surgeon and anesthesiologist alike. We describe a case of an elderly male diabetic patient who developed bilaterally symmetrical lower limb neurological deficit following an uneventful total knee arthroplasty performed under spinal anesthesia. Postoperative nerve conduction study with electromyography confirmed symmetrical extensive denervation of lower limb muscles, including low-voltage fibrillation potentials and positive sharp waves. These findings were consistent with a preexisting neuropathy, thereby suggesting a subclinical neuropathy as a potential risk factor for this neurological complication. Our case highlights the fact that patients with longstanding comorbidities, namely peripheral vascular disease and diabetes mellitus, may be at an increased risk of neurological injury following regional anesthesia. Hence, we believe that preoperative evaluation of diabetic patients should include neurophysiological studies to identify subclinical neuropathy and minimize the risk of neurological injury.