PUDENDAL NERVE BLOCK AND PUDENDAL NERVE NEUROMODULATION IN THE TREATMENT OF CHRONIC PELVIC PAIN DUE TO PUDENDAL NEURALGIA

INTRODUCTION AND AIM OF THE STUDY Pudendal Neuralgia (PN) is a frequent cause of chronic pelvic pain (CPP) in the absence of an organic pathology. Its diagnosis remains still clinical and there is not a definitive cure for it. After medical therapy failure, second level techniques are reserved to drug-refractory patients. Among these, the most widely used technique is represented by pharmacological nerve blocks, which are usually performed under radiological guidance with variable success rates [1]. Another technique is the pudendal nerve neuromodulation, advised for pharmacological block refractory patients, with high success rates in small number series [2]. However, studies regarding these therapies are sparse. The aim of our study was to describe a new technique for performing nerve block procedure and to evaluate block short and long-term efficacy in women with chronic pelvic pain (CPP) secondary to pudendal neuralgia (PN). Moreover, we investigate if neurophysiological tests are predictive for treatment efficacy and risk of disease relapse. The second outcome was the evaluation of the efficacy and safety of pudendal nerve neuromodulation (PNM) for block-refractory patients. MATERIALS AND METHODS We performed a retrospective study on 110 women undergoing pudendal nerve block with ropivacain, heparin and desamethasone under neurophysiological guidance for pudendal neuralgia (PN). Treatment success was considered as a VAS scale improvement>50%. All the women underwent maximum 6 infiltrations and VAS pain was evaluated at baseline and at every infiltration, with a median follow up of 6 months. A multivariate analysis was performed to investigate the anal reflex and somatosensory evoked potentials (SEP) predictive value. Within this cohort, 4 women and one added man were recruited for the first stage of pudendal neuromodulation implant [3]. A descriptive data analysis was performed to evaluate the treatment effectiveness into this fist case series. RESULTS We evaluated 110 women affected by CPP due to PN; age ranged from 26 to 84 years. The neurophysiological guidance guaranteed precision during infiltration. Median follow up was 6 months (range 4–24). A positive response after the nerve block was obtained in 63% patients with a recurrence rate after a median follow up of 6 months of 9%; median VAS score reduced from 10 up to 4. The multivariate analysis did not show a predictive value for treatment effectiveness or for the risk of relapse after treatment of anal reflex and SEP. With regard to the neuromodulation group, 3 months after the implantation, median VAS scale value decreased from 9 to 2 (p = 0,001) and this improvement has maintained even after 12 months (with a median VAS of 3) and without complications. INTERPRETATION OF RESULTS Our results are overlapping to the results of the literature. Literature series are small, with a short follow up and with several approaches and technique. CONCLUSIONS Pudendal nerve block is an effective and safe option for the treatment of PN unresponsive to medical therapy and the neurophysiological guidance allows to inject drugs as closes as possible to the nerve. Chronic pudendal nerve neuromodulation is a feasible and effective procedure in the mid term treatment of refractory CPP.