New, simple, ultrasound-guided infiltration of the pudendal nerve: ultrasonographic technique

Cadaveric Insights into Pudendal Nerve Variations for Sacrospinous Ligament Fixation: A Case Series

INTRODUCTION AND HYPOTHESIS

The proximity of the pudendal nerve to the sacrospinous ligaments (SSLs) can lead to serious complications during sacrospinous ligament fixation (SSLF). This case series is aimed at providing an overview of the anatomy of the pudendal nerve, including insights from cadaver dissections and discussions on rare variations observed during these dissections.

METHODS

Dissections were conducted on five female cadavers using a posterior gluteal approach on both sides. The course, morphometric features and variations in the branches of the pudendal nerve were assessed at the level of the SSL and within the pudendal canal.

RESULTS

The number of pudendal trunks cranial to the SSL ranged from one to three, with double trunks being the most common (70%). In 2 out of 10 (20%) sides inferior rectal nerves (IRNs) pierced through the SSL. In Case 1, IRNs pierced the SSL bilaterally before entering the pudendal canal and exiting at distances of 23.81 mm and 41.18 mm from the ischial spine on the right and left sides respectively. In Case 2, nerves with a width of 2.12 mm and 2.49 mm pierced the SSL and joined the IRN, piercing the SSL at 13.38 mm and 12.55 medial to the ischial spine and 16.80 mm and 19.32 mm lateral to the sacrum, on the left and right sides respectively. In 60% of cases, the IRN entered the pudendal canal, exiting at a median distance of 21.25 mm from the ischial spine.

CONCLUSIONS

We identified significant variations in the number of trunks and branching patterns of the pudendal nerve around the SSL and the course of the IRN caudal to the SSL. We documented IRNs or nerves joining the IRNs piercing the SSL. Identifying these variations is crucial for surgeons to minimize the risk of pudendal nerve injury during SSLF.

Sonoanatomy of the ilioinguinal, iliohypogastric, genitofemoral, obturator, and pudendal nerves: a practical guide for US-guided injections

The ilioinguinal, iliohypogastric, genitofemoral, obturator, and pudendal nerves are the major sensory nerves that may be involved in chronic groin and genital pain with a significant impact on the quality of life of patients. The diagnosis remains clinical, and US-guided diagnostic injections using an anesthetic may aid in confirming the clinical suspicion. The anatomy of the peripheral nerves can be successfully studied using imaging. High-resolution ultrasound is increasingly used in the clinical setting for visualizing small peripheral nerves, and magnetic resonance imaging provides an anatomical overview of the relationship between small nerves and surrounding structures. In this pictorial assay, we review the anatomy and clinical relevance of the ilioinguinal, iliohypogastric, genitofemoral, obturator, and pudendal nerves. We summarize the various techniques for ultrasound identification, and present the ultrasound-guided infiltration techniques for injecting the ilioinguinal, iliohypogastric, genitofemoral, obturator, and pudendal nerves. Corresponding magnetic resonance images and clinical photos of the probe placement technique are provided for anatomical correlation. This paper is aimed to serve as a practical technical guide for physicians to familiarize themselves with the ultrasound anatomy of the major inguinal sensory nerves and to enable successful ultrasound identification and ultrasound-guided diagnostic or therapeutic infiltrations for pain management of the ilioinguinal, iliohypogastric, genitofemoral, obturator, and pudendal nerves.

Therapy With Local Anesthetics to Treat Vulvodynia. A Pilot Study

Introduction

Vulvodynia (chronic vulvar pain) is a sexually debilitating disorder with a prevalence of ∼10%.

Aim

To investigate the effectiveness of therapy with local anesthetics (TLA) in women with severe vulvodynia, we conducted a prospective, non-controlled observational study.

Methods

45 patients with severe chronic vulvodynia (primary and secondary vulvodynia, 0–10 numeric analogue scale (NAS) ≥6, median 7.9, duration ≥6 months, median 65.2 months) in an outpatient practice in Germany were treated with TLA in 3–12 sessions using procaine 1% as local anesthetic. Effectiveness was analyzed with Wilcoxon signed rank tests and Wilcoxon rank sum tests.

Outcomes

Therapeutic success as a reduction of pain to ≤4 NAS lasting for ≥6 months after end of therapy.

Results

TLA successfully reduced vulvodynia in 36 of 45 patients (80 %, responders). The NAS reduction was from 7.9 to 2.4 (P < .001). Even patients denominated as non-responders experienced a significant reduction in NAS (P = .03). In responders, long-term success was observed for 6.8–125 months (median 24.1 months). No adverse events occurred.

Clinical Translation

A promising new treatment for a hard-to-treat chronic female pain disorder.

Strengths and Limitations

Limitation: Monocentric, non-controlled observational design; Strength: the high number of patients treated.

Conclusion

The high success rate of TLA in this investigation offers new perspectives on the etiology of vulvodynia as a complex pain syndrome affecting several nerves of the pelvic floor, and also provides early insight into the effectiveness of TLA in women with vulvodynia.

Weinschenk S, Benrath J, Kessler E, et al. Therapy With Local Anesthetics to Treat Vulvodynia. A Pilot Study. Sex Med 2022;10:100482.

Ultrasound-Guided Pudendal Nerve Block Combined with Propofol Deep Sedation versus Spinal Anesthesia for Hemorrhoidectomy: A Prospective Randomized Study

Background and Objectives. Several anesthesia techniques were applied to hemorrhoidectomy, but postoperative pain and urinary retention were still two unsolved problems. The aim of this prospective randomized study was to evaluate the effect of ultrasound-guided pudendal nerve block (PNB) combined with deep sedation compared to spinal anesthesia for hemorrhoidectomy. Methods. One hundred and twenty patients undergoing Milligan-Morgan hemorrhoidectomy were randomized to receive PNB combined with deep sedation using propofol (Group PNB, n = 60) or spinal anesthesia (Group SA, n = 60). Pain intensity was assessed using the visual analogue scale (0: no pain to 10: worst possible pain). The primary outcome was pain scores recorded at rest at 3, 6, 12, 24, 36, and 48 h and on walking at 12, 24, 36, and 48 h postoperatively. Secondary outcomes were analgesic consumption, side effects, and patient satisfaction after surgery. Results. Ultrasound-guided bilateral PNB combined with deep sedation using propofol could successfully be applied to Milligan-Morgan hemorrhoidectomy. Postoperative pain intensity was significantly lower in Group PNB compared to Group SA at rest at 3, 6, 12, 24, 36, and 48 h (p < 0.001) and during mobilization at 12, 24, 36, and 48 h (p < 0.001) postoperatively. Sufentanil consumption in Group PNB was significantly lower than that in Group SA, during 0-24 h (p < 0.001) and during 24-48 h (p < 0.001) postoperatively. Urinary retention was significantly lower in Group PNB compared to Group SA (6.9% vs 20%, p=0.034). The patients in Group PNB had higher satisfaction compared to Group SA (p < 0.001). Conclusions. Ultrasound-guided PNB combined with propofol sedation is an effective anesthesia technique for Milligan-Morgan hemorrhoidectomy.

Peripheral Nerve Stimulation for Pudendal Neuralgia: A Technical Note

Background

Pudendal neuropathy is a chronic, disabling form of perineal pain that involves the pudendal nerve, a mixed somatic and autonomic nerve that originates from sacral nerve roots. Peripheral nerve stimulation of the pudendal nerve can be useful to decrease symptom burden in patients who have failed initial conservative treatment modalities.

Methods

In this manuscript, we describe an approach to the placement of a peripheral nerve stimulator for the treatment of pudendal neuralgia. We present a case of complex pelvic neuropathy and review the factors that lead to successful placement. Technical aspects of stimulator placement and ultrasound landmarks are reviewed.

Results

A lateral to medial approach with ultrasound guidance at the level of the ischial spine is likely to facilitate proper lead placement along the course of the pudendal nerve. Aftercare and adherence to postimplant activity restrictions–particularly avoiding use of the extremes of hip flexion and extension for four weeks—lead to the absence of lead migration.

Conclusions

Pudendal nerve stimulation is an emerging technique for neuromodulation of refractory pudendal neuralgia. Ultrasound-guided pudendal nerve stimulation is a viable technique for neuromodulation of pudendal neuralgia. Optimization of patient selection, ultrasound guidance, and proper adherence to postimplant activity restrictions may be helpful for long-term therapeutic success.

Pelvic floor muscle training: mechanisms of action for the improvement of genitourinary syndrome of menopause

Objective: This study aims to investigate the mechanism of action of pelvic floor muscle training (PFMT) for the improvement of the signs and symptoms of genitourinary syndrome of menopause (GSM) in postmenopausal women with GSM and urinary incontinence (UI).Methods: Twenty-nine women were included in the secondary analysis of a single-arm feasibility study. Using color Doppler ultrasound, the peak systolic velocity, time-averaged maximum velocity, and pulsatility index of the internal pudendal and dorsal clitoral arteries were measured at rest and after a pelvic floor muscle (PFM) contraction task. PFM function was assessed by dynamometry, and vulvovaginal tissue elasticity was measured using the Vaginal Atrophy Index.Results: PFMT significantly improved blood flow parameters in both arteries (p < 0.05) and significantly increased the speed of PFM relaxation after a contraction (p = 0.003). After the intervention, a marginally significant decrease in PFM tone was observed, as well as an increase in PFM strength (p = 0.060 and p = 0.051, respectively). Finally, improvements in skin elasticity and introitus width were observed as measured by the Vaginal Atrophy Index (p < 0.007).Conclusion: Our findings suggest that PFMT improves blood flow in vulvovaginal tissues, PFM relaxation capacity, and vulvovaginal tissue elasticity in postmenopausal women with GSM and UI.

Ultrasound-guided pudendal nerve block in children: A new technique of ultrasound-guided transperineal approach

BACKGROUND

Transperineal pudendal nerve block guided by nerve stimulator is used in pediatric anesthesia as an alternative to caudal analgesia in perineal surgery. The risk of rectal puncture or intravascular injection is inherent to this blinded technique. We described a new technique of transperineal pudendal nerve block, with ultrasound guidance, to improve safety of the technique.

AIMS

The first goal of this study was to describe this new technique and to test its feasibility. The second objective was to evaluate intra operative effectiveness and postoperative pain control.

METHODS

After parental and children consent, this prospective descriptive study included children aged 1-15 years, ASA status I-III, scheduled for general anesthesia associated with bilateral pudendal nerve block for an elective perineal surgery. After standardized general anesthesia, the anesthesiologist performed pudendal nerve block under ultrasound guidance with "out of plane" approach and evaluated the visualization of anatomical structures (ischial tuberosity, rectum, and pudendal artery), of the needle and of the local anesthetic spread. Pudendal nerve block failure was defined as an increase in mean arterial blood pressure or heart rate more than 20% compared to baseline values after surgical incision. In the postoperative period, the need for rescue analgesia was noted.

RESULTS

During the study period, 120 blocks were performed in 60 patients, including 59 boys. Quality of the ultrasonographic image was good in 81% of blocks, with easy visualization of ischium and rectum in more than 95% of cases. Localization of the tip of the needle was possible for all pudendal nerve blocks, directly or indirectly. The spread of local anesthetic was seen in 79% of cases. The block was effective in 88% of cases.

CONCLUSION

The new technique of ultrasound-guided pudendal nerve block, described in this study, seems to be easy to perform with a good success rate, and probably improves safety of the puncture and of the injection by real-time visualization of anatomical structures and local anesthetic spread.

Ultrasound Detection of Arteria Comitans: A Novel Technique to Locate the Sciatic Nerve

In the gluteal and thigh region, the arteria comitans accompanies the sciatic nerve for a short distance, then penetrates the nerve and runs to the lower part of the thigh. There is no study that recognizes this artery as a guide to the location of the sciatic nerve. In this report, we describe a series of 6 knee arthroplasty patients in whom ultrasound-guided sciatic nerve block was successfully performed using color Doppler and pulsed wave Doppler to visualize the arteria comitans as a guide to the location of the sciatic nerve. We have found that detecting the arteria comitans as a landmark is novel and may offer an additional tool with the existing methods for sciatic nerve block.

Imaging of Pelvic Floor Reconstruction

Stress urinary incontinence and pelvic organ prolapse are 2 common pelvic floor disorders that are important causes of pelvic pain and disability. Mesh and sling placement are some of the surgical treatment options available for treatment of these conditions. In addition to clinical assessment, imaging plays an important role in managing postoperative patients with complications such as recurrent organ prolapse and chronic pain. Role of high-resolution pelvic magnetic resonance imaging with additional advanced imaging techniques, such as magnetic resonance neurography that are invaluable in managing such patients, are discussed in this article.

Minimizing Stimulus Current in a Wearable Pudendal Nerve Stimulator Using Computational Models

After spinal cord injury, functions of the lower urinary tract may be disrupted. A wearable device with surface electrodes which can effectively control the bladder functions would be highly beneficial to the patients. A trans-rectal pudendal nerve stimulator may provide such a solution. However, the major limiting factor in such a stimulator is the high level of current it requires to recruit the nerve fibers. Also, the variability of the trajectory of the nerve in different individuals should be considered. Using computational models and an approximate trajectory of the nerve derived from an MRI study, it is demonstrated in this paper that it may be possible to considerably reduce the required current levels for trans-rectal stimulation of the pudendal nerve compared to the values previously reported in the literature. This was corroborated by considering an ensemble of possible and probable variations of the trajectory. The outcome of this study suggests that trans-rectal stimulation of the pudendal nerve is a plausible long term solution for treating lower urinary tract dysfunctions after spinal cord injury.

New perineal injection technique for pudendal nerve infiltration in diagnostic and therapeutic procedures

PURPOSE

Pudendal nerve injection is used as a diagnostic procedure in the vulvar region and for therapeutic purposes, such as in vulvodynia. Here, we provide a new, easy-to-perform perineal injection technique.

PATIENTS AND METHODS

We analyzed 105 perineal injections into the pudendal nerve with a local anesthetic (LA), procaine in 20 patients. A 0.4 × 40 mm needle was handled using a stop-and-go technique while monitoring the patient's discomfort. The needle was placed 1-2 cm laterally to the dorsal introitus. After aspiration, a small amount of LA was applied. After subcutaneous anesthesia, the needle was further advanced step-by-step. Thus, 5 ml could be applied with little discomfort to the patient. Anesthesia in the pudendal target region was the primary endpoint of our analysis.

RESULTS

In 93 of 105 injections (88.6 %), complete perineal anesthesia was achieved with a single injection. 12 injections were repeated. These injections were excluded from the analysis. Severity of injection pain, on visual analog scale (VAS) from 0 to 100, was 26.8 (95 % CI 7.2-46.4). Age (β = 0.33, p < 0.01) and the number of previous injections (β = 0.35, p < 0.01) inversely correlated with injection pain. Injection pain and anesthesia were not affected by BMI, the number and the side of previous injections, or order of injection. A reversible vasovagal reaction was common, but no serious adverse effects occurred.

CONCLUSION

Perineal pudendal injection is an effective and safe technique for anesthesia in diagnostic (vulva biopsy) and therapeutic indications (pudendal neuralgia), and regional anesthesia in perinatal settings.

[Not Available]

Le syndrome du canal d’Alcock – ou névralgie pudendale – est lié à la compression chronique du nerf pudendal dans la fossette ischio rectale ou au niveau du ligament sacroépineux. Le diagnostic du syndrome d’Alcock est surtout clinique. Les examens complémentaires sont dominés par les explorations électrophysiologiques et le test de bloc anesthésique. Le diagnostic repose sur des critères bien précis, soit les critères de Nantes. La prise en charge doit être globale, comprenant un traitement médicamenteux, des infiltrations, des techniques de neuromodulation, et dans les cas graves ou résistants, un traitement chirurgical qui consiste à libérer le nerf pudendal. Les névralgies pudendales peuvent être rencontrées après traitement d’une incontinence urinaire d’effort par bandelettes sous-urétrales (TVT). Ce syndrome motive des consultations en urologie, car la douleur intéresse le territoire du périnée et des organes génitaux. Des signes urinaires peuvent aussi accompagner cette douleur. Il est donc judicieux de connaître cette pathologie.

[Ultrasound in interventional pain therapy]

Peripheral nerve blocks are currently performed relatively blind even in the most complex anatomical structures and physicians mostly rely on palpable anatomical landmarks on the surface. Ultrasound has become an indispensable part of the modern medical world and has long since found its way into almost all medical professions. More and more this trend also reaches interventional pain physicians as it is possible to accurately target structures, to track the needle course during the intervention and to visualize the spread of the local anesthetic. Another advantage compared to other radiological techniques is the profound radiation safety for patients as well as for personnel performing the intervention. A deep understanding of anatomy and its correlate in ultrasound images is one of the most important requirements for the successful use of these interventional techniques. Moreover, the safe performance of the procedure depends on the simultaneous hand-eye coordination. Nevertheless, despite the euphoria ultrasound technology should only be used in pain management with sufficient indications.

[Ultrasound in interventional pain therapy]

Peripheral nerve blocks are currently performed relatively blind even in the most complex anatomical structures and physicians mostly rely on palpable anatomical landmarks on the surface. Ultrasound has become an indispensable part of the modern medical world and has long since found its way into almost all medical professions. More and more this trend also reaches interventional pain physicians as it is possible to accurately target structures, to track the needle course during the intervention and to visualize the spread of the local anesthetic. Another advantage compared to other radiological techniques is the profound radiation safety for patients as well as for personnel performing the intervention. A deep understanding of anatomy and its correlate in ultrasound images is one of the most important requirements for the successful use of these interventional techniques. Moreover, the safe performance of the procedure depends on the simultaneous hand-eye coordination. Nevertheless, despite the euphoria ultrasound technology should only be used in pain management with sufficient indications.

Nerve-stimulator-guided pudendal nerve block by pararectal approach

AIM

Various techniques have been described for performing a pudendal nerve block (PNB) and have associated problems such as multiple needle injections, the need for special equipment and consumption of time. This study aimed to describe a nerve-stimulator-guided PNB using a pararectal approach and to evaluate the safety and the efficacy of that procedure.

METHOD

We conducted a prospective study of 53 patients who underwent a PNB from December 2009 to July 2010. With the index finger of the left hand inserted into anus, we guided the nerve stimulator needle along the second finger tip on the ischial spine to the site where the maximal contraction of the external anal sphincter could be felt. Once the position of the needle tip had been confirmed, the desired drug was injected. Of the 53 patients, a cohort of eight underwent manometry before and after the pudendal block.

RESULTS

A total of 53 patients underwent the nerve-stimulator-guided procedure: 13 patients for pudendal neuralgia and the other 40 patients for anorectal disease. The mean maximal resting and squeezing pressures before the block were 55 and 161 mmHg, respectively, compared with 35 and 67 mmHg after the block. The PNB took just minutes to perform, was well tolerated by the patients, and resulted in neither severe complications nor repeated attempts.

CONCLUSION

Nerve-stimulator-guided PNB using a pararectal approach proved to be easy and safe, with acceptable patient tolerance. In addition, it can be used for a variety of anorectal procedures where relaxation of anal tone is required.

A new minimally invasive technique for pudendal nerve stimulation

AIM

Pudendal nerve stimulation (PNS), which is an alternative to sacral nerve stimulation, requires neurophysiological confirmation of correct siting of the electrode. We describe a modification of the existing technique where placement is assisted by guidance to the ischial spine by a finger introduced per anum.

METHOD

Cadaveric dissection was carried out to confirm the accuracy of this new approach. The surface marking of the ischial spine is marked. A stimulating needle electrode inserted through a skin incision at this point, is advanced towards the ischial spine using a finger introduced per anum as a guide. Once effective stimulation of the pudendal nerve is confirmed by observed and palpated contraction of the anal musculature, a permanent stimulating electrode is inserted and the position confirmed by radiological screening.

RESULTS

Using cadaveric studies, the correct surface markings for needle placement were confirmed. This technique was then applied successfully for in vivo insertion of the needle electrode in 20 patients with bowel dysfunction, with only one lead displacement occurring over a mean follow-up period of 12 months.

CONCLUSION

Finger-guided assistance of PNS electrode insertion is simple and reproducible without requiring neurophysiological confirmation of nerve stimulation to ensure correct lead location.

[Somatic nerve block in the management of chronic pelvic and perineal pain]

INTRODUCTION

Chronic pelvic and perineal pain can be related to a nerve lesion caused by direct or indirect trauma or by an entrapment syndrome, which must then be demonstrated by a test block. The purpose of this article is to review the techniques and modalities of somatic nerve block in the management of chronic pelvic and perineal pain.

MATERIAL AND METHODS

A review of the literature was performed by searching PubMed for articles on somatic nerve infiltrations in the management of chronic pelvic and perineal pain.

RESULTS

Nerves involved in pelvic and perineal pain are: thoracolumbar nerves (obturator, ilioinguinal, iliohypogastric and genitofemoral) and sacral nerves (pudendal and inferior cluneal branches of the posterior cutaneous nerve of the thigh). Infiltration has a dual objective: to confirm the diagnostic hypothesis by anaesthetic block and to try to relieve pain. Evaluation of the severity and site of the pain before and immediately after the test block is essential for interpretation of the block. The various infiltration techniques for each nerve are described together with their respective advantages, disadvantages and risk of complications.

CONCLUSION

Somatic nerve blocks are an integral part of the management of chronic pelvic and perineal pain and are predominantly performed under CT guidance in order to be as selective as possible. Once the diagnosis and the level of the nerve lesion have been defined, more specific therapeutic procedures can then be proposed.

Fluoroscopy-guided pudendal nerve block and pulsed radiofrequency treatment : A case report

Pudendal nerve block (PNB) is performed for differential diagnosis and treatment of chronic pelvic and perineal pain. Several block methods, such as transvaginal, transperineal, computerized tomography-, ultrasound- and fluoroscopy-guided approach are currently under practice. Compared to others, a fluoroscopy-guided approach has several advantages, such as its relatively low cost, facility and ease of landmark recognition. We depicted a fluoroscopy-guided PNB technique to selectively block and elaborate a pulsed radiofrequency treatment in a 51-year-old man with chronic pelvic and perineal pain. The patient had undergone a ganglion of impar block with a limited pain relief. Thereafter, a PNB was performed and the pain was relieved significantly for 2 weeks. Further PNB with a pulsed radiofrequency treatment reduced the pain for more than 8 weeks. The pain relief sustained up to the time of this report. The fluoroscopy-guided PNB and pulsed radiofrequency treatment allowed simplicity in manipulation and precision in performing the procedures with a favorable outcome.

C-arm-guided pudendal nerve block: a new technique

Pudendal nerve block (PNB) is an effective diagnostic and/or treatment method for perineal pain. Various approach techniques, such as transperineal, transvaginal, computerised tomography (CT)- or sono-guided approach, have been suggested for this block. However, they have some limitations, such as high cost, difficulty to perform in practice, inaccurate and unreliable results and inconvenience. To overcome these limitations, we first tried C-arm-guided approach for accomplishing PNB in the prone position. Under the optimal ischial spine view of C-arm fluoroscopy, the block needle was placed on the tip of the ischial spine. Then a mixed solution for the block was administered. All of the 25 patients enrolled in this study were blocked successfully using this method. No side-effects or complications were observed in relation to the block. We concluded that the C-arm-guided approach for PNB is an effective alternative to the existing techniques, which can overcome their limitations.

Fascicular anatomy and surgical access of the human pudendal nerve

The ability to access selectively distal nerve branches at the level of the compound pudendal nerve (PN) would allow control of multiple neural pathways and genitourinary functions at a single location. Nerve cuff electrodes can selectively stimulate individual fascicles; however the PN fascicular anatomy is unknown. The fascicular representation of distal branches was identified and traced proximally to create fascicle maps of 12 compound PNs in seven cadavers. Distal nerves were represented as groups of individual fascicles in the PN. Fascicle maps were consistent between specimens and along the PN within specimens. PN branch free length was 26+/-7.7 mm. PN cross-sections were relatively flat with major and minor diameters of 4.3+/-0.90 and 1.7+/-0.45 mm, respectively. Placing a nerve cuff on the PN is anatomically and surgically feasible. The PN fascicular anatomy, branch free length, and cross-section geometry are conducive to selective stimulation of distal nerves with a single nerve cuff electrode.