Interstitial cystitis / bladder pain syndrome (IC/BPS) is defined as “an unpleasant sensation (pain, pressure, discomfort) perceived to be related to the urinary bladder, associated with lower urinary tract symptoms of more than six weeks duration, in the absence of infection or other identifiable causes” [1]. Sacral neuromodulation is approved by the United States Food and Drug Administration (FDA) for the treatment of urinary urgency / frequency associated with overactive bladder (OAB), with placement of the implanted pulse generator indicated in the setting of clinically significant improvement in lower urinary tract symptoms (LUTS). Likewise, percutaneous tibial nerve stimulation (PTNS) has established efficacy in treating refractory OAB and is also FDA approved [2]. Our primary outcome was to investigate the efficacy of PTNS in managing IC/BPS. Further the published literature has suggested that diabetes is not associated with worsening outcomes of PTNS in OAB, yet there is no study that investigated the effect of psychiatric comorbidities on the success of PTNS in either OAB or IC/BPS [3]. Our secondary outcomes include the effects of diabetes mellitus and psychiatric comorbidities on the success of PTNS therapy.

We performed a retrospective chart review analysis of patients who completed at least 10 weekly treatments of PTNS from January 1st, 2010, and October 1st, 2021After obtaining IRB approval, IC/BPS patients were screened using STARR and data were analyzed accordingly using SAS Studio with missing data excluded final analysis. Paired 2-tailed t-test was performed to analyze continuous variables within subject changes in LUTS before and after treatment. Fisher exact test was performed on categorical variables, to explore the effects of diabetes and psychiatric co-morbidities on the outcomes of PTNS. Success rate is defined by clinical improvement in LUTS equal to or more than 50%, or patient satisfaction with the improvement in his/her LUTS.

34 patients (25 female, 9 male) were identified with an average age of (52.9±16.8). The BMI of the population was on the overweight side with mean of 27.9±6.3 and had an HbA1c of 5.7±1%. Our study population tend to have an increased number of comorbidities (mean, 6.2±4.6), and an increased number of allergies (mean, 3.5±5.7).

Success rate was 50% (17/34) with 13 patients (13/34, 38.2%) proceeding to maintenance phase. Out of the 13 patients who proceeded to maintenance, five patients (5/13, 38.5%) discontinued maintenance PTNS. Duration of maintenance therapy was 6.7±9.8 months. Interval between daytime voids improved the most from 1.325±0.71 hours at the baseline and improved to 1.9±1.1 hours after therapy which equals an improvement of 0.58±0.8 hours (46.2%, n=16, p=0.01). Urinary urgency improved from 3±1.1 at baseline to 1.7±1.4 after therapy by 1.3±1.5 points on Urgency Severity Scale (43.3%, n=11, p=0.02, USS range 0-4). Nocturia episodes were decreased from 3.6±2 at baseline to 2.5±1.7 points after therapy which equates improvement by 1.1±1.6 points (30.6%, n=28, p=0.001). Regarding pain domains, 12 weeks of PTNS treatment resulted in a non-statistically significant improvement in pain in the O’Leary Sant International Cystitis Symptoms Index questionnaire (ICSI) with an improvement from 2.4±1.4 at baseline to 1.8±1.9 points after therapy which equals an improvement by 0.7±1.1 points (25%, n=11, p=0.13). 

Psychiatric comorbidities and diabetes were not significantly associated with observed differences in PTNS success rate.

PTNS can be an effective treatment option for patients with IC/BPS, with expected potential improvements noted in urinary urgency, frequency, and nocturia. Our study did not find a statistically significant improvement in pelvic pain in response to PTNS as measured by question 4 of the O’Leary Sant ICSI. The same is true for diabetic patient and patients with psychiatric comorbidities as there was no statistically significant difference in success rates in diabetic or psychiatric patients versus patients with no history of diabetes or psychiatric comorbidity. 

Physicians may counsel patients that PTNS is a viable treatment option for IC/BPS patients with psychiatric comorbidities. The combination of IC/BPS – which is an already uncommon and an underdiagnosed disease - and diabetes mellitus, makes it necessary to establish a multi-center cohort to determine the exact effect of how diabetes affects the outcomes of PTNS. Physicians should encourage patients who had been successfully treated with PTNS to continue maintenance to preserve the therapeutic benefit gained from the induction phase of PTNS as the rate of discontinuation during PTNS maintenance was 38.5% which remains a significant number that should be considered in the management plan. Considering the large value of the standard deviation for each of LUTS, Patients should be counseled that the improvement in the successful management of LUTS will vary significantly between patients depending on the severity of symptoms (except for pain).

PTNS is a promising therapeutic modality for management of urgency frequency, and nocturia in IC/BPS patients. Physicians may consider PTNS as a treatment option for patients with IC/BPS.

Hanno P, Dmochowski R. Status of international consensus on interstitial cystitis/bladder pain syndrome/painful bladder syndrome: 2008 snapshot. Neurourol Urodyn. 2009;28(4):274-286. doi:10.1002/nau.20687
Staskin DR, Peters KM, MacDiarmid S, Shore N, de Groat WC. Percutaneous tibial nerve stimulation: a clinically and cost effective addition to the overactive bladder algorithm of care. Curr Urol Rep. 2012;13(5):327-334. doi:10.1007/s11934-012-0274-9
Zeno A, Handler SJ, Jakus-Waldman S, Yazdany T, Nguyen JN. Percutaneous Tibial Nerve Stimulation in Diabetic and Nondiabetic Women With Overactive Bladder Syndrome: A Retrospective Cohort Study. Female Pelvic Med Reconstr Surg. 2021;27(11):686-690. doi:10.1097/SPV.0000000000001036