V12-04: Placement of an Implantable Tibial Nerve Stimulator Under Local Anesthesia: Step by Step Instructions
Video
INTRODUCTION
The treatment of non-neurogenic overactive bladder (OAB) follows an algorithmic pathway. Patients who fail initial treatment options may be offered peripheral tibial nerve stimulation (PTNS). An implantable tibial lead may help overcome the time commitment that limits pursuit of the percutaneous approach of this type of neuromodulation. The lead is implanted in an optimized anatomical location based on neurosensory testing in a single office visit. The patient undergoes stimulation of their lead at home. A number of different devices with variations on this theme are currently being evaluated. We present an anatomical review and instructional video for the placement of an implantable tibial nerve stimulator for the treatment of OAB under pure local anesthesia.
METHODS
Anatomy localization using ultrasound can be used to identify arterial, venous and nerve structures posterior to the medial malleolus and approximately 5 cm superior. An external probe is used to elicit twitching of the flexor digitorum brevis muscle and the site on the skin that elicits a strong motor response is marked. An incision is made 5 centimeters proximal and the probe is inserted at a 20-30 degree angle as it is directed to the marked neurosensory site. The probe pierces the flexor retinaculum to come into appropriate proximity with the nerve. If the lead is in proximity to the nerve, the patient will experience stimulation from the probe with subsequent toe fanning or flexor digitorum brevis muscle twitching. The introducer set is positioned to the tip of the probe and the dilator and probe are removed, leaving the introducer sheath in place. The lead is inserted through the sheath until it is at the tip of the sheath. The sheath is retracted to expose the electrodes of the lead. Neurosensory response is confirmed. The anchor on the lead is deployed to fix the lead in place. The excess wire is buried under the skin.
RESULTS
Five women have undergone placement of an implantable PTNS leads at our institution. Mean procedure duration is 18 minutes. Mean EBL is 5 mLs. Mean follow up is 5.2 months. Three patients reported ecchymosis at the site where the lead was tunneled, and there have been no reported post procedure complications.
CONCLUSION
Placement of an implantable PTNS lead in the outpatient setting with local anesthesia is relatively quick with no major complications in our small cohort. The procedure is dependent on neurosensory responses, although ultrasound may be used. Efficacy of the procedure is still in progress.
Funding: Bioness, Inc.