Lead placement and associated nerve distribution of an implantable periurethral electrostimulator

The aim of this study was to determine gross and neuroanatomic features of a novel periurethral neuromuscular electrostimulator. Periurethral leads were placed in eight female cadavers. In two cases, leads were imaged after placement to enhance anatomic understanding. Pelvic viscera were removed en bloc for analysis of lead placement in the six remaining cadavers. Excised tissue was sectioned and immunostained to identify general, afferent, sympathetic, and nitric oxide synthase efferent nerve fibers. The electrodes were found within/lateral (n = 4), within/posterolateral (n = 9), and anterolateral (n = 1) to the external urethral sphincter (distance 0.25 +/- 0.5, 2.9 +/- 3.3, and 1.0 +/- 0.0 mm, respectively). The electrode to the urethra and vagina distance averaged 7.6 +/- 3.4 and 8.8 +/- 4.3 mm, respectively. Variable density staining for all nerve types was found around the electrode. A periurethral electrode interfaces the external urethral sphincter, and the adjacent distribution of nerve fibers supports proposed neuromuscular therapeutic mechanisms.