Pudendal Nerve Mapping Towards Improved Neuromodulation for Urinary Retention

University of Michigan22 enrolled

Overview

This study is to map the pudendal nerve. In this study the researchers will examine subjects who are already receiving an implanted stimulator at their pudendal nerve as part of their normal clinical care.

The pudendal nerve goes to the urethra, anus, and other areas of the pelvic floor. Electrical stimulation of this nerve can help with bladder problems and pelvic pain. Researchers do not understand how the nerve anatomy is different between people. Successfully mapping the pudendal nerve may help improve the medical care for future patients with bladder problems, pelvic pain, bowel problems, and sexual problems.

Study Type

INTERVENTIONAL

Allocation

Purpose

BASIC_SCIENCE

Masking

NONE

Enrollment

Conditions

Urinary Retention Underactive Bladder

Interventions

Participants received a Neurostimulator, which was used to map the pudendal nerveDEVICE

Participants in study received neurostimulator at their pudendal nerve as part of their normal clinical care. This neurostimulator was used to map the nerve.

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Clinically referred as having bladder problems that have not responded to conservative treatment. Normal clinical care includes referral to implant of Medtronic Interstim neurostimulator at the pudendal nerve. Fully eligible to receive an Interstim implant. * Adult (18 or older), capable of providing own informed consent and communicating clearly with research team * Capable of speaking, reading, and understanding English, as all study questionnaires are standardized assessments only available in English * Capable of attending all experimental sessions (Visit 1: pre-stage-1 imaging, Visit 2: stage-1 surgery, Visit 3: CT after stage-2 surgery, Visit 3: cystometrogram test) Exclusion * Implanted materials that prohibit magnetic imaging * Any medical problems that prevent an individual from laying flat in an MRI or CT scanner, are are claustrophobic. * Areflexive or atonic bladder * Pregnant or planning to become pregnant. If a woman of child-bearing potential wishes to participate in this study, they will be pre-screened with a test to detect pregnancy. * Diagnosed neurogenic bladder, pudendal nerve damage, lower motor dysfunction, or other conditions that would affect the neural circuits involved in micturition. * Unwilling to allow de-identified data to be stored for future use or shared with other researchers.

Locations (1)

University of Michigan

Ann Arbor, Michigan, United States

Outcomes

Primary Outcomes

Number of Participants With Evoked Bladder Contractions of at Least 20 Centimeters of Water (cmH2O) During the Stage-4 Test

The primary outcome measure in this study was an evoked bladder contraction of at least 20 centimeters of water (cmH2O) during the cystometrogram. These bladder contractions were evoked by applying nerve stimulation to the pudendal nerve through testing of the participant's implanted stimulator. Measure reflects number of participants who experienced an evoked bladder contraction of at least 20 centimeters of water during nerve stimulation.

Time frame: Visit 4, approximately 10 weeks after consent

Secondary Outcomes

Selectivity Index (SI) for Selective Stimulation of Pudendal Nerve Branches for Participant Stimulation

Selectivity refers to the degree in which a nerve could be stimulated without stimulating other nerves. SI was calculated for each sensor recording from locations innervated by distal pudendal nerve branches during the visit-2 implant procedure. This includes pressure sensors in the urethra innervated by the perineal nerve and anal electromyography (EMG) innervated by the ischeal rectal nerve. The SI calculation used here is on a scale of 0 to 1, with 0 indicating no response at all from the nerve. The closer the number is to 1, the more selective the nerve stimulated.

Time frame: Visit 2: Stage-1 (approximately 3 weeks after consent)

Selectivity Index (SI) for Selective Stimulation of Pudendal Nerve Branches for Simulated Model Stimulation

Selectivity is the degree to which part of a nerve could be stimulated without stimulating other nerve parts. For each participant who had successful MRI and CT images, a computational model was created to simulate electrical stimulation of axons distributed in two primary pudendal fascicles: perineal and rectal. The SI of stimulation does not indicate a positive or negative result in this outcome; rather, it shows the relative potential for activating just a single nerve fascicle. The negative/positive designation identifies the regional nerve activation, with -1 representing only perineal fascicle activation, +1 representing only rectal activation, and 0 indicating equal activation of both fascicles.

Data from ClinicalTrials.gov

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