Secondary changes in bowel function after successful treatment of voiding symptoms with neuromodulation

Expanded indications for neuromodulation are continually being explored. We evaluated secondary changes in bowel function after successful neuromodulation for voiding symptoms.

Patients in our prospective neuromodulation database study with comorbid irritable bowel syndrome (IBS), constipation and/or diarrhea, or fecal incontinence (FI) at baseline were evaluated. Pre- and 3, 6, and 12 months post-operative measures included Interstitial Cystitis Symptom Index and Problem Index (ICSI-PI), bowel diaries (assessing bowel movement frequency; constipation, diarrhea, and FI episodes), and scaled global response assessments (GRA) ("markedly worse" to "markedly improved" bowel function).

Most patients reporting secondary bowel problems (128/199; 64.3%) were female (89%; mean age 56 ± 15.4 years). Primary voiding complaints were urgency/frequency (U/F) with or without urinary incontinence (n=74), interstitial cystitis/painful bladder syndrome (IC/PBS; n=43), and urinary retention (n=11). Secondary bowel complaints included constipation and/or diarrhea (49%), IBS (27%), and FI (23%). Urinary (ICSI-PI) scores improved after treatment (P<0.0001 for IBS and constipation/diarrhea; P=0.0021 for FI). Bowel diary data only indicated that mean FI episodes/day increased over time (P = 0.0100) in the FI group. Only the 12-month value (1.4 ± 2.2; n=8) was significantly different from baseline (0.3 ± 0.5; n = 18). On the GRA, only the IBS group consistently reported bowel function improvement versus worsening at each time point. Many reported no change.

Studies have indicated that neuromodulation improves FI in carefully selected patients. The impact on other bowel conditions, including IBS, is unclear. Since voiding and bowel symptoms often coexist, it is crucial to fully evaluate all potential treatment benefits.