Sacral neuromodulation in patients with detrusor underactivity: Is biological sex an indicator?

Abstract

Objectives This study aimed to report sacral neuromodulation (SNM) outcomes in detrusor underactivity (DU). Methods A multicentric, multinational, retrospective case series was conducted between March 2017 and June 2021 in three different referral centers. Initial test phase stimulation included either a percutaneous nerve evaluation (PNE) or an advanced lead evaluation test phase (ALTP) before permanent SNM implantation. The test phases were performed under local anesthesia, either in the outpatient (PNE) or operating room (ALTP), in the prone position, which was implanted in the third or fourth sacral foramina under fluoroscopic guidance. Patients with favorable response to the initial test phase during the first 2 weeks underwent the implantable pulse generator (IPG) implantation (Medtronic neurostimulation generator device InterStim™). Favorable response was defined as ≥ 50% improvement in symptoms, frequency of clean intermittent catheterization (CIC) and/or decrease in postvoid residual (PVR), increase in voided volume, or improvement in bladder voiding efficiency (BVE) based on the bladder diary. Results Fifty‐eight patients were recruited with a mean age of 39.95 ± 15.28 years. Among the 58 cases, 36 (62.1%) patients responded to the initial stage. Of these, 12 patients (30.8%) with non‐neurogenic etiology and nine patients (52.9%) with neurologic etiology did not respond to the initial test phase; thus, they did not undergo full implantation (p = 0.141). Voided volume, PVR, and the median maximum flow rate (Qmax) improved significantly (p < 0.001) in both sexes; however, there was no statistical difference between both genders. Most female cases (78.3%), and nearly half of the men (51.4%), responded to the test phase and were candidates for the IPG phase. Among the 35 cases who underwent IPG, 27 patients (72.2% of males, and 77.8% of females; p = 0.700) had a favorable response to IPG. 46.6% of patients had a successful outcome at the end of the study. Conclusion This multicentric study showed that SNM effectively and safely provided symptom improvement in refractory DU in males similar to females which is an important finding as previously it has been suggested that SNM works better in nonobstructive urinary retention in women and not in women.

Underactive Bladder and Detrusor Underactivity: New Advances and Prospectives

“…Existing studies appear to be contradictory. A multicenter retrospective study reported successful outcomes in 46.6% of patients undergoing SNM, with no significant difference between the sexes [132]. Nevertheless, Coolen et al reported a markedly higher success rate in women than in men (62% vs. 22%).…”

Can we improve techniques and patients' selection for nerve stimulation suitable for lower urinary tract dysfunctions? ICI‐RS 2023

“…46 There are data that SNS may be effective in both men and women with DU, but patients with preserved bladder contractility are more likely to respond favorably to SNS compared with patients who lack detrusor contractions. 47 The sacral anterior root stimulation, also known as the Brindley-Finetech implant, was used often in the past to trigger detrusor contractions; despite promising results, a decline in implantations has been observed. 48 This decline has been linked to the complication rate, treatment failure, and need for dorsal rhizotomy.…”

“…Detrusor underactivity (DU) is defined as a contraction of reduced strength and/or duration, resulting in prolonged bladder emptying and/or a failure to achieve complete bladder emptying within a normal time span 46 . There are data that SNS may be effective in both men and women with DU, but patients with preserved bladder contractility are more likely to respond favorably to SNS compared with patients who lack detrusor contractions 47 . The sacral anterior root stimulation, also known as the Brindley‐Finetech implant, was used often in the past to trigger detrusor contractions; despite promising results, a decline in implantations has been observed 48 .…”