Editor-in-Chief: Kenneth D. Candido, MD
Small fiber neuropathy (SFN) is a disorder of small afferent nerve fibers that can result in debilitating pain and functional limitations. There are many etiologies including, but not limited to, diabetes, vitamin deficiencies, infections, and exposure to neurotoxic drugs such as chemotherapeutics. The constellation of signs and symptoms overlap with other disease states leading to potential misdiagnosis. New tests including histologic studies of skin biopsies and autonomic nerve tests have emerged in the last 20 years improving differentiation between these disease processes and SFN.
Multiple chemotherapeutic medications have been implicated in causing SFN, including vincristine which was the causative agent in this case report. The exact incidence of chemotherapy-induced peripheral neurotoxicity (CIPN) is currently unknown, but according to some publications it has been reported to be as high as 40% in patients that have been treated with chemotherapy. As the number of cancer survivors continues to grow, the number of patients with painful SFN will potentially increase.
Devising an effective analgesic regimen for patients with painful SFN can be difficult, and often requires the pain physician to employ multiple pharmacologic and non-pharmacologic therapies. Treatments include analgesics from several drug classes: antidepressants, opioids, and anticonvulsants. Often times however, more advanced interventional techniques must be employed as effective pain control may be limited by medication side effects or inadequate return of function.
While dorsal column stimulation was approved for a limited number of applications, a number of new applications are reported in the literature. In this paper, we present a case of vincristine-induced SFN successfully treated with neuromodulation via spinal cord stimulator.
Key words: Vincristine, vinblastine, chemotherapy-induced neuropathy, chronic pain, spinal cord stimulation, dorsal column stimulation, neuromodulation, small fiber neuropathy, neuropathic pain