RETROSPECTIVE STUDY ANALYZING THECORRELATION BETWEEN URODYNAMIC PARAMETERS AND TREATMENT OUTCOMESFOLLOWING TRIGONAL NERVE ABLATION VIA RADIOFREQUENCY ENERGY
M. GRATTON1, M.FOURNIER 2, V. MOUAJOU 3, P. O. RICHARD 4,L. TU 5;
1Urology, Sherbrooke Univ.,Sherbrooke, Canada, 2Univ. de Sherbrooke, Sherbrooke,Canada, 3Sherbooke Univ., Sherbrooke, Canada, 4Universitæde Sherbrooke; Ctr. de recherch, Sherbrooke, Canada, 5Ctr.Hosp.ier Univ.ire de Sherbrooke, Sherbrooke, Canada.
Introduction: Overactive bladder(OAB) is a very prevalent disease that affects 15-21% of thepopulation. Initial management consists of bladder training, weightloss and fluid management. If these behavioral modifications fail,the second line therapy usually consists of antimuscarinics or Beta-3agonists. Reports have shown that many patients takingantimuscarinics for OAB are nonadherent (up to 85%) and that nearly75% of them will discontinue treatment within 1 year due mainly tothe drug-related side effects, inadequate drug efficacy and poorpatient education. Third lines therapies exist, but these are moreinvasive in nature and many patients are not responsive to them. Onenew treatment option being investigated is fulguration of thetrigonal nerves via radiofrequency ablation (RFA). RFA uses heatgenerated from alternating currenti. It was demonstratedwith 3D mapping of human bladder innervation that myelinated sensoryneurons and preganglionic parasympathetic fibers traverse theadventitia and penetrate the detrusor predominantly near the bladderneck at the 3 o’clock and 9 o’clock positions as well as aroundthe ureteral orifices and interureteric ridgeii.Therefore, RFA can specifically treat the highly rich in nerve regionof the trigone without affecting surrounding tissue.
Objective:This is a retrospective institutional ethic board approved study. Ourcenter is part of a multicenter study. The objectives were toevaluate whether there is correlation between the baseline urodynamicparameters and clinical outcomes following fulguration.
Methods:From a prospectively maintained database, we retrospectively reviewedall cases of trigonal RFA at our institution. The device used fortreatment is only available as part of a clinical trial. It includesa lumen to accommodate a 30o cystoscopic lens for directvisualization of the trigone during the procedure. RF cannulae wereinserted through the device and an aspiration of the trigonal mucosawith a suction paddle was done. This way we targeted the nerves at adepth of approximately 3.0 mm and RF was administrated across thetrigone. All cases were performed by a single surgeon. Patients werecategorized into two groups: i) Uninhibited bladder contraction (UBC)positive patient on pre-treatment urodynamic study (UDS) (UBC+) andii) UBC negative patient on pre-treatment UDS (UBC-). Clinical datawere available for all patients and four main postprocedural outcomeswere compared between the groups at three months, namely: subjectiveimprovement rates (IR), treatment benefits scale (TBS), 24hPad-weight test (PWT) and number of urgency urinary incontinence/72h(UUI/72h). Baseline characteristics, voiding diaries and UDS findingsbetween both groups were compared using Wilcoxon rank-sum tests forcontinuous variables and using either chi-square or Fisher exacttests for categorical variables.
Results: A total of 22patients were identified during the study period. Of these, 12 werefound to have positive UBC on the baseline UDS. When the baselinecharacteristics, voiding diaries and UDS findings of patients with orwithout UBC were compared, no statistical differences were observedbetween both groups. Likewise, no statistical differences wereobserved between the 3-months voiding diaries and the UDS findings ofboth groups. However, patients in the UBC- group reported asignificantly greater 3-months improvement rate (70% vs 40%; p=0.03)than their counterparts.
Conclusions: UBC- patients wereassociated with statistically significant better IR at 3 monthsfollowing treatment. This suggests trigone ablation provides agreater benefit for this subset of patients with OAB refractory tomedical therapy. However the sample size limited the interpretationof some of the analysis. Further study is required to validate theseresults.
References: i RF ablation results incoagulative necrosis of tissue from high temperatures [⋯]as alternating current is applied. ii [⋯]one can appreciate the density of nerves that are most apparent atthe 3 o’clock and 9 o’clock positions on the bladder neck[⋯].From each of these two bundles, there is a band of nerves trackingbetween the bladder neck and the interureteric ridge.