The Use of Pulsed Radiofrequency for the Treatment of Pudendal Neuralgia: A Case Series

Accuracy of augmented reality-guided needle placement for pulsed radiofrequency treatment of pudendal neuralgia: a pilot study on a phantom model

Background

Pudendal neuralgia (PN) is a chronic neuropathy that causes pain, numbness, and dysfunction in the pelvic region. The current state-of-the-art treatment is pulsed radiofrequency (PRF) in which a needle is supposed to be placed close to the pudendal nerve for neuromodulation. Given the effective range of PRF of 5 mm, the accuracy of needle placement is important. This study aimed to investigate the potential of augmented reality guidance for improving the accuracy of needle placement in pulsed radiofrequency treatment for pudendal neuralgia.

Methods

In this pilot study, eight subjects performed needle placements onto an in-house developed phantom model of the pelvis using AR guidance. AR guidance is provided using an in-house developed application on the HoloLens 2. The accuracy of needle placement was calculated based on the virtual 3D models of the needle and targeted phantom nerve, derived from CBCT scans.

Results

The median Euclidean distance between the tip of the needle and the target is found to be 4.37 (IQR 5.16) mm, the median lateral distance is 3.25 (IQR 4.62) mm and the median depth distance is 1.94 (IQR 7.07) mm.

Conclusion

In this study, the first method is described in which the accuracy of patient-specific needle placement using AR guidance is determined. This method could potentially improve the accuracy of PRF needle placement for pudendal neuralgia, resulting in improved treatment outcomes.

The Efficacy of an Ultrasound-Guided Improved Puncture Path Technique of Nerve Block/Pulsed Radiofrequency for Pudendal Neuralgia: A Retrospective Study

Objectives: To investigate the efficacy and safety of an improved ultrasound-guided pulsed radiofrequency (PRF) and nerve block (NB) for patients with pudendal neuralgia (PN). Methods: This retrospective analysis included 88 adults with PN treated in the Pain Department of Southwest Hospital from November 2011 to June 2021, with treatment including NB (n = 40) and PRF (n = 48). The primary outcome variable was pain severity, measured by a standardized visual analog scale (VAS). VAS values were collected at 1, 3, 7, and 14 days and 1 and 3 months after patients were treated with NB or PRF. Results: Compared with patients treated with NB (n = 40) and those treated with PRF (n = 48), no significant difference in pain reduction was observed in the short term (p = 0.739 and 0.981, at 1 and 3 days, respectively); however, in the medium and long term (1 to 3 months), there were statistically significant improvements in the PRF group over the NB group (p < 0.001). Moreover, it was noted that the average pain severity of primary PN and PN due to sacral perineurial cyst was significantly reduced with PRF therapy in the medium and long term when compared to other secondary PNs, including surgery, trauma, and diabetes. Discussion: The ultrasound-guided, improved, and innovative PRF/NB puncture path technique allows for gentler stimulation and faster identification of the pudendal nerve. The PRF technique may provide better treatments for primary PN and sacral perineurial cyst causing secondary PN in the medium and long term.

Advances in the therapeutic approach of pudendal neuralgia: a systematic review

CONTEXT

Although pudendal neuralgia (PN) has received growing interest over the last few years, diagnosis remains difficult, and many different therapeutic approaches can be considered.

OBJECTIVES

This article aims to provide an overview of the possible treatments of PN and investigate their efficacies.

METHODS

Utilizing PubMed and ScienceDirect databases, a systematic review was carried out and allowed identification of studies involving patients with PN, as defined by Nantes criteria, and their associated treatments. Relevant data were manually reported.

RESULTS

Twenty-eight articles were selected, totaling 1,013 patients (mean age, 49 years) and six different types of interventions. Clinical outcomes, most frequently quantified utilizing the Visual Analog Scale (VAS), vary greatly with both the therapy and time after intervention (from 100 to <10%). However, neither peri nor postoperative serious complications (grade > II of Clavien-Dindo classification) are reported. Although surgery seems to provide a higher proportion of long-term benefits, identifying the most efficient therapeutic approach is made impossible by the multitude of outcome measurements and follow-up frequencies. It should also be noted that literature is sparse regarding randomized controlled trials with long-term follow-up.

CONCLUSIONS

Although there are a number of modalities utilized for the treatment of PN, there are no current recommendations based on treatment efficacies. This seems to be largely in part caused by the lack of standardization in outcome quantification. Future research in this field should focus on prospective cohort studies with high levels of evidence, aimed at assessing the long-term, if not permanent, benefits of available therapies.

The Use of Radiofrequency in the Treatment of Pelvic Pain

Radiofrequency ablation (RFA) is a procedure in which radio waves are used to destroy abnormal or dysfunctional tissue. It has been an increasingly utilized treatment option for a variety of medical conditions, such as chronic pain, wherein sensory nerves are targeted and ablated, eliminating their ability to transmit pain signals to the brain. There is a lack of clarity regarding the indications, technique, and efficacy of RFA for chronic pelvic pain. This article reviews recent literature and discusses these topics, including adverse events for different pelvic ablation and pulsed radiofrequency treatment of chronic pelvic pain.

Diagnostic and therapeutic algorithm for pudendal nerve entrapment syndrome

Pudendal nerve entrapment syndrome is widely unknown and often misdiagnosed or confused with other pelvic floor diseases. The aim is to develop a diagnostic and therapeutic algorithm based on a review of the existing literature. For its diagnosis, an anamnesis will be carried out in search of possible aetiologies, surgical history, and history of pain, assessing location and irradiation, intensity on the visual analogue scale, timing, triggering factors and rule out alarm signs. A physical examination will be performed, looking for trigger points or areas of fibrosis with transvaginal / transrectal palpation of the terminal branches of the nerve. With a doubtful diagnosis, an anaesthetic block of the pudendal nerve can be performed. Once the diagnosis is confirmed, the treatment will begin staggered with lifestyle changes, drug therapy and physiotherapy. In view of the failure of these measures, invasive therapies such as botulinum toxin injection, pulsed radiofrequency and decompression surgery or spinal cord stimulation will be used.

Percutaneous CT-Guided Cryoablation of the Bilateral Pudendal Nerves for Palliation of Intractable Pain Related to Pelvic Neoplasms

Objectives:

The purpose of this report is to describe the effect of computed tomography–guided bilateral pudendal nerve cryoablations on pain and time to discharge in the setting of acute hospitalizations secondary to refractory pelvic pain from cancer.

Methods:

Investigators queried the medical record for patients who underwent pudendal nerve cryoablation using the Category III Current Procedural Technology code assignment 0442T or Category I code 64640 for cases prior to 2015. The resulting list was reviewed, and procedures performed on inpatients for intractable pelvic pain related to neoplasm were selected. The final cohort was then analyzed with regard to patient demographics, procedure details, technical success, safety, pain scores, and time to discharge.

Results:

Ten patients underwent cryoablation by 3 operators for palliation of painful pelvic neoplasms between June 2014 and January 2019. All probes were satisfactorily positioned and freeze cycles undertaken without difficulty. There were no procedure-related complications or adverse events. The mean difference in pre- and posttreatment worst pain scores was significant (n = 5.20, P = .003). The mean time to discharge following the procedure was 2.3 days.

Conclusion:

Computed tomography–guided percutaneous cryoablation of the bilateral pudendal nerves may represent a viable option in the setting of acute hospitalization secondary to intractable pain in patients with pelvic neoplasms.

Percutaneous imaging-guided techniques for the treatment of benign neuropathic pain

To date, conservative management including physical and/or systemic pharmacologic therapy is considered as the first line approach for the management of neuropathic pain syndromes. In the era of an opioid overdose crisis with an increased concern upon the risks and harms arising from the misuse of medicines for pain management, percutaneous minimally invasive techniques such as nerve infiltrations as well as neurolysis or neuromodulation techniques can be proposed to control pain and improve life quality. Computed tomography can serve as an ideal guiding technique due to its specific characteristics including precise anatomic delineation, high spatial resolution and good tissue contrast. The purpose of this review is to make the reader familiar with the most common indications for minimally invasive imaging-guided techniques in patients with neuralgia and provide current evidence regarding technical considerations.