Topographic anatomy of a new posterior approach to the pudendal nerve for stimulation

Current role of neuromodulation in bladder pain syndrome/interstitial cystitis

Neuromodulation is recommended by major international guidelines as a fourth-line treatment in bladder pain syndrome/interstitial cystitis (BPS/IC) patients after failure of behavioural, oral and intravesical pharmacological treatments, including hydrodistension. A non-systematic review of studies identified by electronic search of MEDLINE was performed with no time limitation. A narrative synthesis of the existing evidence regarding the results of sacral, tibial and pudendal nerve stimulation in the management of BPS/IC was developed. Neuromodulation in pelvic chronic pain disorders, including BPS/IC, is a useful tool for refractory patients to conventional treatments. Sacral neuromodulation may be effective in patients with BPS without Hunner's lesions, and the effect seems to be maintained in the mid- and long-term. Posterior tibial nerve stimulation can be offered to patients with BPS/IC in the context of a multidisciplinary approach. When pudendal neuralgia is suspected, selective pudendal nerve stimulation has a high response rate. The aetiology of the pain can influence the outcomes in the mid- and long-term of the different neuromodulation approaches, thus careful diagnosis is recommended.

Neuromodulation of the Pudendal Nerve Assisted by 3D Printed: A New Method of Neuromodulation for Lower Urinary Tract Dysfunction

Electrical stimulation of peripheral nerves by implanted electrodes is an effective treatment for certain pelvic floor diseases. As well as intravesical electrical stimulation, this predominantly includes stimulation of the sacral nerve, tibial nerve, and pudendal nerve. The pudendal nerve is one of the main nerves that stimulate pelvic floor muscles, external urethral meatus, and the anal sphincter and pelvic organs, and it may have effects on frequent urination, urgency, dysuria, and perineal pain. It is difficult to locate because of its anatomical course, however, leading to difficulties fixing the electrode, which increases the difficulty of pudendal nerve electrical stimulation in clinical practice. In the current study 3D printed navigation was used to solve these problems. Combined with autopsy data and patient pelvic and nerve data, a personalized design was generated. Neural modulation of the pudendal nerve was achieved by implanting the lead with the guidance of 3D printed navigation. 3D printed navigation can maximize the phase II conversion rate, reduce the difficulty of surgery, shorten the operation time, reduce damage to additional organs and blood vessels, and increase the accuracy of electrode implantation, and it can be performed while the patient is awake. It is an accurate, reversible, efficient, and minimally invasive surgery.

Pudendal Nerve Electroacupuncture for Lumbar Spinal Canal Stenosis – a Case Series

Objective

To investigate the effectiveness of pudendal nerve electroacupuncture for lumbar and lower limb symptoms in patients with lumbar spinal canal stenosis for whom acupuncture of the lumbar and lower limb muscles had been ineffective.

Methods

Nine patients with lumbar spinal canal stenosis for whom conventional acupuncture at the lumbar and lower limb muscles had no effect. Pudendal nerve electroacupuncture was performed eight times (once per week). VAS scores and continuous walking distance were used to evaluate changes in symptoms.

Results

The following changes in symptoms occurred after pudendal nerve electroacupuncture: low back pain was improved from 45.3±17.4mm (mean ± SD) to 39.2±14.0mm, lower limb pain was improved from 61.1±5.6mm to 35.4±11.9mm, lower limb dysaesthesia was improved from 63.9±8.4mm to 46.9±16.2mm, and continuous walking distance was improved from 100.0±35.4m to 250.0±136.9m.

Conclusion

Pudendal nerve electroacupuncture may be an effective treatment for lumbar and lower limb symptoms due to spinal canal stenosis, and is potentially useful in patients who have not responded to conventional acupuncture.

New laparoscopic approach to the pudendal nerve for neuromodulation based on an anatomic study

AIMS

The aim was to develop a new laparoscopic technique for placement of a pudendal lead.

METHODS

Development of a direct, feasible and reliable minimal-invasive laparoscopic approach to the pudendal nerve (PN). Thirty-one embalmed human specimens were dissected for the relevant anatomic structures of the pelvis. Step-by-step documentation and analysis of the laparoscopic approach in order to locate the PN directly in its course around the medial part of the sacrospinous ligament and test this approach for feasibility. Landmarks for intraoperative navigation towards the PN as well as the possible position of an lead were selected and demonstrated.

RESULTS

The visible medial umbilical fold, the intrapelvine part of the internal pudendal artery, the coccygeus muscle and the sacrospinous ligament are the main landmarks. The PN traverses the medial part of the sacrospinous ligament dorsally, medially to the internal pudendal artery. The medial part of the sacrospinous ligament has to be exposed in order to display the nerve. An lead can be placed ventrally on the nerve or around it, depending on the lead type or shape.

CONCLUSIONS

A precise and reliable identification of the PN by means of laparoscopy is feasible with an easy four-step approach: (1) identification of the medial umbilical fold; (2) identification of the internal iliac artery; (3) identification of the internal pudendal artery and incision of the coccygeus muscle ('white line', arcuated line); and (4) exposition of the medial part of the sacrospinous ligament to display the PN.

First experiences with pudendal nerve stimulation in fecal incontinence: a technical report

Sacral nerve stimulation (SNS) is an established treatment for refractory lower urinary tract and bowel dysfunction. In some urological patients, SNS does not have satisfactory results. Pudendal nerve stimulation (PNS) has recently been proposed for these patients and successfully tested. Given the sometimes unsatisfactory results after SNS in fecal incontinence (FI), we tested PNS on patients suffering from FI. We used the device and implantation technique described by Spinelli et al. By making a slight change in the device, we developed a quick and easy-to-use method for successful PNS implantation, based on electrophysiological response. We present the results of a feasibility study, in which we tested the effectiveness of PNS with our modified implantation technique on 2 patients, with very satisfactory early results in a 4-month follow-up.

The overactive bladder

Urinary urgency and the associated symptoms which comprise overactive bladder are prevalent amongst the general population and adversely affect quality of life. Disease management consists of a sequential series of options starting with behavioural and lifestyle techniques, pharmacological management (antimuscarinics) and, in severe cases, surgical treatment (urinary diversion, neuromodulation, augmentation cystoplasty and detrusor myectomy). There is increasing recognition of pathophysiological mechanisms in the urothelium, interstitial cells and afferent neurons allowing the importance of peripheral integrative interaction to be identified. The hierarchy of the central nervous system control adds additional complexity to understanding the oflower urinary tract function. Some newer methods of treatment include Botulinum toxin A intramural injections, oral beta-3 adrenergic agonists and rho-kinase inhibitors. The lack of a disease generating hypothesis, the lack of animal models for disease and the subjective nature of the central symptom (urgency) still pose considerable theoretical and scientific hurdles that need to be overcome in the treatment of this condition.