Women Undergoing Third Line Overactive Bladder Treatment Demonstrate Elevated Thermal Temporal Summation

Abstract

Purpose To determine if women with overactive bladder (OAB) requiring 3rd line therapy demonstrate greater central sensitization, indexed by temporal summation to heat pain stimuli, than those with OAB. Materials and Methods We recruited 39 adult women with OAB from the Urology clinic who were planning to undergo interventional therapy for medication refractory OAB with either onabotulinumtoxinA bladder injection or sacral neuromodulation and 55 women with OAB, either newly seen in our Urology clinic or responding to advertisements for study participation. Participants underwent quantitative sensory testing using a thermal temporal summation protocol. The primary study outcome was the degree of temporal summation, as reflected in the magnitude of positive slope of the line fitted to the series of 10 stimuli at a 49°C target temperature. We compared the degree of temporal summation between study groups using linear regression. Results Women in the group undergoing 3rd line therapy demonstrated significantly higher standardized temporal summation slopes compared to those in the nontreatment group (beta = 1.57, 95% confidence interval = .18 - 2.96, t = 2.25, p = .027). On exploratory analyses, a history of incontinence surgery or hysterectomy were factors associated with significantly greater temporal summation. Conclusions In this study, the degree of temporal summation was elevated in women undergoing 3rd line OAB therapy compared to women with OAB not undergoing 3rd line therapy. These findings suggest there may be pathophysiologic differences, specifically in afferent nerve function and processing, in some women with OAB.

<p>Novel Characterization Of Thermal Temporal Summation Response By Analysis Of Continuous Pain Vs Time Curves And Exploratory Modeling</p>

“…The current study focuses on thermal TS, which typically involves the delivery of a set of identical, noxious heat pulses to the body via a thermode. Thermal TS can be delivered in a standardized fashion, is generally well tolerated, and has been widely studied 4,6–12…”

Clustering of patients with overactive bladder syndrome

“…Conceptually it is possible that the systemic cluster might have “top-down” or systemic mechanisms such as central sensitization, systemic inflammation, or psychosocial trauma. Central sensitization has recently been demonstrated in some OAB patients by Reynolds et al [ 8 , 9 ]. In future studies it is important to study the differences in pathophysiology among the OAB subtypes.…”

“…Reynolds et al have shown that patients requiring third line treatment for OAB (“refractory” patients) demonstrated higher rates of central sensitization when compared to patients who were first presenting for OAB treatment (treatment naïve) [ 9 ]. This observation lends credence to our hypothesis.…”

“…Recent research suggested that non-urologic factors such as anxiety, depression, psychological stress, somatic symptom burden, non-urologic pain, and increased hypersensitivity related to central sensitization might contribute to the symptomatology of OAB and other lower urinary tract symptoms (LUTS) [4][5][6][7][8][9][10]. This observation raises the possibility that the OAB population is heterogeneous and may be further sub-categorized based on their non-urologic factors in addition to their urinary symptoms.…”

Stress-induced analgesia: an evaluation of effects on temporal summation of pain and the role of endogenous opioid mechanisms

“…A standardized oscillating heat pain stimulation protocol (Medoc TSA 2001, Minneapolis, MN) was used to determine temporal summation, similar to our previous work. 40 , 43 A sequence of 10 heat pulses, 0.5 seconds in duration, with a 35°C base temperature, an intertrial interval of 2.5 seconds, and 50°C target stimulus intensity was applied to the left volar forearm. Participants were asked to provide verbal numeric pain ratings (0 = “no pain” to 100 = “most pain possible”) immediately after the peak of each pulse.…”