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

Technical aspects of a new approach to intraoperative pelvic neuromonitoring during robotic rectal surgery

It has been found that rectal surgery still leads to high rates of postoperative urinary, fecal, or sexual dysfunction, which is why nerve-sparing surgery has gained increasing importance. To improve functional outcomes, techniques to preserve pelvic autonomic nerves by identifying anatomic landmarks and implementing intraoperative neuromonitoring methods have been investigated. The objective of this study was to transfer a new approach to intraoperative pelvic neuromonitoring based on bioimpedance measurement to a clinical setting. Thirty patients (16 male, 14 female) involved in a prospective clinical investigation (German Clinical Trials Register DRKS00017437, date of first registration 31/03/2020) underwent nerve-sparing rectal surgery using a new approach to intraoperative pelvic neuromonitoring based on direct nerve stimulation and impedance measurement on target organs. Clinical feasibility of the method was outlined in 93.3% of the cases. Smooth muscle contraction of the urinary bladder and/ or the rectum in response to direct stimulation of innervating functional nerves correlated with a change in tissue impedance compared with the pre-contraction state. The mean amplitude (Amax) of positive signal responses was Amax = 3.8%, negative signal responses from a control tissue portion with no stimulation-induced impedance change had an amplitude variation of 0.4% on average. The amplitudes of positive and negative signal responses differed significantly (statistical analysis using two-sided t-test), allowing the nerves to be identified and preserved. The results indicate a reliable identification of pelvic autonomic nerves during rectal surgery.

Diagnosis and treatment of pudendal and inferior cluneal nerve entrapment syndrome: a narrative review

AIM

Pudendal and inferior cluneal nerve entrapment can cause a neuropathic pain syndrome in the sensitive areas innervated by these nerves. Diagnosis is challenging and patients often suffer several years before diagnosis is made. The purpose of the review was to inform healthcare workers about this disease and to provide a basis of anatomy and physiopathology, to inform about diagnostic tools and invasive or non-invasive treatment modalities and outcome.

METHODS

A description of pudendal and inferior cluneal nerve anatomy is given. Physiopathology for entrapment is explained. Diagnostic criteria are described, and all non-invasive and invasive treatment options are discussed.

RESULTS

The Nantes criteria offer a solid basis for diagnosing this rare condition. Treatment should be offered in a pluri-disciplinary setting and consists of avoidance of painful stimuli, physiotherapy, psychotherapy, pharmacological treatment led by tricyclic antidepressants and anticonvulsants. Nerve blocks are efficient at short term and serve mainly as a diagnostic tool. Pulsed radiofrequency (PRF) is described as a successful treatment option for pudendal neuralgia in patients non-responding to non-invasive treatment. If all other treatments fail, surgery can be offered. Different surgical procedures exist but only the open transgluteal approach has proven its efficacy compared to medical treatment. The minimal-invasive ENTRAMI technique offers the possibility to combine nerve release with pudendal neuromodulation.

CONCLUSIONS

Pudendal and inferior cluneal nerve entrapment syndrome are a challenge not only for diagnosis but also for treatment. Different non-invasive and invasive treatment options exist and should be offered in a pluri-disciplinary setting.

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.

Modified Laparoscopic Percutaneous Extraperitoneal Closure Using a Sledge-Shaped Needle for Inguinal Hernia and Hydrocele in 1199 Pediatric Patients

Background: The objective of the study is to determine the safety and efficiency of the modified laparoscopic percutaneous extraperitoneal closure (LPEC) to treat pediatric patients with inguinal hernia or hydrocele. Methods: From January 2014 to July 2018, the patients with inguinal hernia or hydrocele who were operated on using modified LPEC were included. We modified LPEC with a sledge-shaped needle and reinforcement flag. By means of medial umbilical fold, the reinforcement surgery should be performed on the patients with huge internal rings (diameter >1.5 cm). Operative time, complication rate, incidence of reinforcement, and contralateral patent processus vaginalis were described between inguinal hernia and hydrocele. Results: In this study, 764 patients with inguinal hernia and 435 patients with hydrocele were successfully performed by the modified LPEC. The 383 (50.1%) patients with inguinal hernia and 266 (61.1%) patients with hydrocele were identified with a contralateral patency of internal ring and underwent simultaneous prophylactic surgery. During surgical procedures, the medial umbilical fold reinforcement (inguinal hernia/hydrocele = 50/1) was performed on 51 patients. Hernia recurrence occurred in 2 cases. All patients had a good cosmetic appearance without additional dissection. Conclusion: Modified LPEC using a sledge-shaped needle and applying the medial umbilical fold reinforcement is a safe and effective surgical procedure.

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.

Endoscopic trans gluteal minimal-invasive approach for nerve liberation (ENTRAMI technique) in case of pudendal and/or cluneal neuralgia by entrapment: One-year follow-up

BACKGROUND

Chronic neuropathic perineal pain syndrome is a collective term that encompasses several diagnoses. In patients where the neuropathic pain syndrome is caused by pudendal or cluneal nerve entrapment, surgical release can be proposed if other measures have failed. The aim of this study is to evaluate the clinical outcome of patients suffering from pudendal and/or cluneal nerve entrapment at 1 year after this minimal invasive surgery, which is based on the open trans gluteal approach who has proven its efficacy compared to medical treatment in a randomized control trial.

METHODS

Patients eligible for inclusion had chronic perineal neuropathic pain for at least 3 months in the area served by the pudendal and/or cluneal nerve, refractory to conservative measurements. Patients met all five of the Nantes criteria.

RESULTS

Fifteen patients underwent the ENTRAMI technique. At 1 year after surgery, overall reduction of the average maximal Numeric Pain rating Scale (NPRS-score) was from 9 (range, 7-10) at baseline to 5 (range, 0-10; P-value <.05). At 1 year 73% of patients declared to have a "good treatment response" (patient global impression of change [PGIC] >30%) and optimal treatment response (PGIC ≥90%) was found in 40% (P-value <.05). No complications were recorded.

CONCLUSION

This study clearly shows that the technique is feasible with promising long-term results in a difficult to manage patient group.

Laparoscopic selective pudendal neuromodulation for neurogenic bladder: a review of literature

This study presents an alternative technique for neuromodulation in cases where percutaneous sacral implantation is difficult or has previously failed. We aimed to describe a novel technique of selective placement of an electrode over the pudendal nerve (PN), via laparoscopic approach in a patient with urinary retention who previously failed sacral neuromodulation (SNM) treatment.

A minimally invasive, endoscopic transgluteal procedure for pudendal nerve and inferior cluneal nerve neurolysis in case of entrapment: 3- and 6-month results. The ENTRAMI technique for neurolysis

BACKGROUND

Pudendal and cluneal nerve entrapment can cause a neuropathic pain syndrome in the sensitive areas innervated by these nerves. Recently, a new endoscopic minimal invasive approach for pudendal and inferior cluneal nerve neurolysis has been published in a cadaver study. The aim of our study was to describe the feasibility of this new approach and to evaluate the clinical outcome.

METHODS

Fifteen patients underwent the ENTRAMI technique. The Numeric Pain Rating Scale (NPRS) and Patient Global Impression of Change (PGIC) were recorded at baseline and at 3 and 6 months after surgery.

RESULT

The average duration of intervention (skin to skin) was 139 min (range 50-270 min) for bilateral pudendal neurolysis and/or cluneal neurolysis and 113 min (range 100-130 min) for unilateral pudendal and/or cluneal neurolysis. No perioperative blood loss occurred. At 3 months, 50% of patients declared a more than 30% improvement of their PGIC, increasing to 57% at 6 months; 31% reported more than 90% improvement of PGIC at 6 months. Overall reduction of the average maximal NPRS score was from 9 (range 7-10) to 6 at 3 months (range 0-10; p value < 0.05) and to 5 at 6 months (range 0-10; p value < 0.05). There were no postoperative complications.

CONCLUSIONS

The ENTRAMI technique is feasibly in patients suffering from pudendal and/or cluneal neuralgia and preliminary results are promising.

CLINICAL TRIAL NUMBER

NCT03883178.

Division of Sacrospinous and Sacrotuberous Ligaments Expands Access Through Greater Sciatic Foramen: Anatomic Study with Application to Resection of Greater Sciatic Foramen Tumors

OBJECTIVE

Tumors of the greater sciatic foramen remain difficult to treat. They often have both intrapelvic and extrapelvic components that may limit visualization and make safe resection of the tumor difficult. Therefore the goal of the present anatomic study was to quantitate how much additional surgical working space could be gained by transection of the sacrospinous and sacrotuberous ligaments.

METHODS

Sixteen sides from 9 fresh-frozen Caucasian cadaveric torsos underwent transgluteal dissection and exposure of the greater sciatic foramen and associated liagments. With the piriformis in place, the vertical and horizontal diameters of the greater sciatic foramen were measured. Next, the sacrotuberous and sacrospinous ligaments were cut at their ischial attachments. The vertical diameter of the now confluent greater and lesser sciatic foramina (V₂) was measured.

RESULTS

The mean vertical diameter of the greater sciatic foramen (V₁) was 54.8 ± 9.7 mm. The horizontal diameter of the greater sciatic foramen had a mean of 44.3 ± 6.1 mm with a range of 30-52 mm. After transection of the sacrotuberous and sacrospinous ligaments, the vertical distance of the greater and lesser sciatic foramina (V₂) had a mean of 74.8 ± 6.8 mm with a range of 60.1-90 mm. The mean ratio of V₂ to V₁ was 1.40.

CONCLUSIONS

The vertical length of the greater sciatic foramen increased, on average, 40% after resection of the sacrotuberous and sacrospinous ligaments. The results of this study support an alternative technique for resecting large intrapelvic tumors via a transgluteal approach.

A new endoscopic minimal invasive approach for pudendal nerve and inferior cluneal nerve neurolysis: An anatomical study

AIM

To describe a new minimal invasive approach of the gluteal region which will permit to perform neurolysis of the pudendal and cluneal nerves in case of perineal neuralgia due to an entrapment of these nerve trunks.

METHOD

Ten transgluteal approaches were performed on five cadavers. Relevant anatomic structures were dissected and further described. Neurolysis of the pudendal nerve or cluneal nerves were performed. Landmarks for secure intraoperative navigation were indicated.

RESULTS

The first operative trocar for the camera was inserted with regards to the iliac crest in the deep gluteal space. With the aid of pneumodissection, the infragluteal plane was dissected. The piriformis muscle was identified as well as the sciatic and the posterior femoral cutaneous nerve. Consequently, the sciatic tuberosity was visualized together with the cluneal nerves. Hereafter, the second trocar was introduced caudal to the first one and placed on an horizontal line passing at the level of the coccyx, allowing access to the ischial spine and the visualization of the pudendal nerve and vessels. A third 5 mm trocar was then inserted medial from the first one, permitting to dissect and transsect the sacrospinous ligament. The pudendal nerve was subsequently transposed and followed on its course in the pudendal channel.

CONCLUSIONS

A reliable exploration of the gluteal region including identification of the sciatic, pudendal, and posterior femoral cutaneous nerves is feasible using a minimal invasive transgluteal procedure. Consequently, the transposition of the pudendal nerve and the liberation of the cluneal nerves can be performed.

The supraorbital region revisited: An anatomic exploration of the neuro-vascular bundle with regard to frontal migraine headache

BACKGROUND

Recent findings on the pathogenesis of frontal migraine headache support, besides a central vasogenic cause, an alternative peripheral mechanism involving compressed craniofacial nerves. This is further supported by the efficiency of botulinum toxin injections as a new treatment option in frontal migraine headache patients.

METHODS

The supraorbital regions of 22 alcohol-glycerine-embalmed facial halves of both sexes were dissected. Both the supratrochlear and supraorbital nerves (STN and SON, respectively) were identified, and their relationship with the corrugator supercilii muscle (CSM) was investigated by dissection and ultrasound. The course of both nerves was defined, and the interaction between the supraorbital artery (SOA) and SON was determined.

RESULTS

We discovered a new possible compression point of the STN passing through the orbital septum and verified previously described compression points of both STN and SON. Osteofibrous channels used by the STN and SON were found constantly. We described the varying topography of the STN and CSM, the SON and CSM, and the SON and SOA. Further, we provide an algorithm for the ultrasound visualization of the supraorbital neurovascular bundle.

CONCLUSION

Our data support the hypothesis of a peripheral mechanism for frontal migraine headache because of following potential irritation points: first, the CSM is constantly perforated by the SON and frequently by the STN; second, the topographic proximity between SOA and SON and the osteofibrous channels is used by the SON and STN; and third, the STN passes through the orbital septum.

The blood supply to the sacrotuberous ligament

Knowledge of the vascular supply associated with the sacrotuberous ligament is incomplete, and at most attributed to a single coccygeal branch. Our aim was to investigate the sacrotuberous ligament vasculature with a focus on its origin and distribution. We dissected 21 hemipelvises (10 male and 11 female). The gluteus maximus was reflected medially, and a special emphasis was placed on the dissection of the vascular and neuronal structures. All specimens exhibited several (1-4) coccygeal arteries branching from the inferior gluteal artery penetrating the sacrotuberous ligament along its length. Seven specimens demonstrated the superior gluteal artery supplying sacral branches to the proximal superior border of the sacrotuberous ligament. Our study highlights several branches from a variety of origins as the supply to sacrotuberous ligament unlike previous reports stating only one vessel. Our results implicate surgical procedures in and around the area of the gluteal region such as decompressive procedures of the pudendal nerve, as it travels between the sacrotuberous and sacrospinous ligaments.