P050: INCREASED URINARY URGENCY AND FREQUENCY AFTER SPINAL CORD STIMULATOR IMPLANTATION
Dilip Kamath, MD; Gabe Mascaro, MD; Dennis Patin, MD; University of Miami Health System
Introduction: Neuromodulation, primarily in the form of spinal cord stimulation (SCS), has been around since the 1960s (1). SCS generates electrical impulses to modify transmission of sensory signals in the spinal cord. Leads are placed under fluoroscopic guidance and confirmation of correct placement is indicated by a patient’s symptoms responding to stimulation. However, the precision of stimulation in terms of only targeting the pathological pathways of interest is unknown.
Statement: In this case report, we describe previously unreported side effects of urinary urgency and frequency associated with stimulation.
Case Presentation: A Hispanic female in her late sixties with a history of post-laminectomy syndrome underwent successful trial and subsequent implantation of a spinal cord stimulator. At her two week post-operative visit, the patient had complete resolution of her back and leg pain. However, she complained of new onset urinary incontinence. An MRI was ordered and showed no acute changes. Comparison with prior imaging studies was also insignificant. She presented to Urology for further workup. Labs revealed a urinary tract infection, which was treated completely. Despite treatment, she continued to have urgency and frequency associated specifically with stimulation. She only had these symptoms with the device on and they resolved when the device was turned off. Device reprogramming was unsuccessful in alleviating her symptoms so the decision was made to remove her implant. After successful explantation, the patient reported no further urgency or frequency.
Discussion: The more commonly described complications of SCS include hardware problems, such as lead migration or lead fracture, or biological issues, such as infection or hematoma. A review of literature reveals only a few case reports of uncommon side-effects of stimulation that appear related to stimulation of neighboring neural pathways. In 2010, La Grua et al. reported a case of unexpected urinary retention with stimulation that required self catheterization (2). La Grua et al. also reported a case of gastrointestinal symptoms including constipation, abdominal pain and distention with stimulation (3). Vorenkamp et al. described a case of severe nausea with stimulation (4). In all three cases, the symptoms had a temporal relation to stimulation and presented immediately post-operatively. The patients were all treated with device reprogramming and only the patient with nausea had complete resolution of symptoms. Specific to our case, control of micturition involves three efferent pathways that innervate the lower urinary tract: the pelvic parasympathetic nerves arising at the sacral level of the spinal cord, the lumbar sympathetic nerves, and the somatic pudendal nerves. Afferent axons travel by way of the pelvic, hypogastric, and pudendal nerves from the lower urinary tract to the lumbosacral spinal cord. Dysfunction of any of these pathways could lead to urinary symptoms. Central axons of the dorsal root ganglion afferent fibers of the pelvic and pudendal nerves enter the spinal cord and travel rostrocaudally within Lissauer’s tract, which lies in close relation to the dorsal columns (5). It is possible our patient had unintended stimulation of Lissauer’s tract leading to her symptoms of urgency and frequency.