Herpes zoster following sacral nerve stimulation for overactive bladder.

Abstract

Shingles, or herpes zoster, is a viral infection caused by reactivation of the varicella-zoster virus, which commonly causes chickenpox in childhood. This virus remains dormant in nerve ganglia. When reactivated, it leads to the development of cutaneous blisters in a dermatomal distribution based on the nerve root affected. Many factors have been theorized to prompt viral reactivation, such as an immunocompromised state (for example in the elderly), trauma and stress. There are a limited number of case reports of herpes zoster following neurosurgery where nerve root manipulation led to shingles outbreaks. To our knowledge we report the first case of herpes zoster following placement of a sacral nerve root electrode for neuromodulation of overactive bladder. CASE REPORT A 73-year-old woman with refractory symptoms of urinary frequency, urgency and urge incontinence, as well as fecal incontinence who had previously failed anticholinergic therapy underwent first stage placement of a sacral nerve root electrode while under local anesthesia and intravenous sedation. With the patient in the prone position, the third sacral foramen on the right side was identified using a foramen needle under fluoroscopic guidance. An angiographic catheter (14 gauge) was then advanced through the S3 foramen, and a permanent quad electrode was then positioned anterior to the right S3 foramen. Thus, the electrode traversed the S3 foramen and ended anterior to the sacrum, adjacent to the lumbosacral nerve plexus. Electrical stimulation confirmed proper positioning, with perceived sensations in the rectum and vagina. In addition, fluoroscopy confirmed positioning of the electrode at the S3 level. An external pulse generator was connected and the patient was instructed on use of the device. She was discharged home the same day on oral antibiotics. The patient returned approximately 1 week postoperatively complaining of significant pain in the right lower extremity. She reported significant improvement in urinary frequency, urgency and urge incontinence, as well as complete resolution of fecal incontinence. The stimulation settings of the quad electrode were changed in an attempt to reduce the lower extremity discomfort, which was thought to be related to stimulation of the second sacral nerve roots. The patient then returned on postoperative day 10 complaining of a painful rash along the right inner thigh. Physical examination revealed erythematous, fluid filled blisters along the right inner thigh and medial portion of the right knee, consistent with L2 and L3 dermatomal distributions (see figure). The sacral electrode was disconnected from any electrical stimulation, and the patient received a course of oral acyclovir and analgesics. She denied any history of herpes zoster. The outbreak resolved within several weeks. However, the patient has not undergone conversion to an internal pulse generator due to concurrent medical problems. To date, she has not undergone restimulation of the electrode.