Feasibility of Real-Time Ultrasound for Pudendal Nerve Block in Patients with Chronic Perineal Pain:

Transvaginal pudendal nerve blocks in patients with pudendal neuralgia: 2-year follow-up results

PURPOSE

Pudendal neuralgia (PN) is an extremely painful neuropathy of the pudendal nerve resulting in a negative impact on a patient's quality of life. The aim of this study is to evaluate the 2-year outcomes of repetitive doses of the transvaginal pudendal nerve injections (PNI), and to compare the success of the PNI concerning anatomical levels (endopelvic and extrapelvic portion) of the pudendal nerve pathology.

METHODS

This retrospective longitudinal cohort study consists of patients with PN diagnosed with the first four essential Nantes criteria. Diagnostic PNI was performed on 67 patients to fulfill the fifth criteria of Nantes. A total of 56 patients who responded to the initial diagnostic PNI underwent therapeutic repeated transvaginal PNIs twice for 3 weeks apart. Mean pain intensity scores were measured using a visual analog scale at the 1st, 3rd, 6th, 12th, and 24th months after the therapeutic blocks were completed. Effectiveness of the PNIs' was defined as ≥ 50% improvement of the initial pain, and relative improvement was defined as 30-50% improvement of the initial pain. Treatment failure was defined as the reduction of the initial pain by less than 30% or the return of the pain to its worst condition.

RESULTS

The efficacy of the PNIs significantly declined over time. Pudendal nerve blocks provided a significant decrease in pain scores; however, this decrease lost its strength significantly in the 24th month. The intervention was more effective in entrapments of the pudendal nerve between sacrospinous and sacrotuberous ligaments or below (Level-2) when compared to the injuries in the endopelvic part (Level-1). More than 50% pain reduction continued in five patients with pathology at Level-1 and 24 patients with pathology at Level-2.

CONCLUSION

Repeated PNIs could provide a significant decrease in pain scores for both short- and long-term periods. However, the efficacy of the PNIs declined over 2 years. The success of PNIs may be affected by the anatomical level of the nerve injury; therefore, interligamentous pudendal nerve entrapment cases have more benefits than the cases of pudendal nerve entrapment in the endopelvic part. However, it is recommended to perform therapeutic nerve blocks even in patients with suspected endopelvic pudendal nerve pathology before the referral to surgery.

Lumbosacral paraspinal interfascial plane blocks for pain control after feminizing genital gender affirmation surgery

Aim: Feminizing genital gender affirmation surgery (fgGAS) is increasing in prevalence in the USA. Management of postoperative pain following fgGAS is challenging. We report a series of patients where post-fgGAS pain was adequately controlled with paraspinal blocks. Materials & methods: This is a case series of three patients who received bilateral lumbar and sacral erector spinae plane blocks after fgGAS. Block techniques, medications administered, opioid requirements and pain scores were reviewed. Results: Erector spinae plane blocks provided adequate analgesia for 24-48 h following the block. Conclusion: Currently, there are two regional anesthetic techniques described for the treatment of postoperative pain after fgGAS. We describe two additional approaches as options for improved pain management in this patient population.

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.

Comparison of Ultrasound-Guided Transgluteal and Finger-Guided Transvaginal Pudendal Nerve Block Techniques: Which One is More Effective?

Purpose

Pudendal neuralgia (PN) is a painful and disabling condition, which reduces the quality of life as well. Pudendal nerve infiltrations are essential for the diagnosis and the management of PN. The purpose of this study was to compare the effectiveness of finger-guided transvaginal pudendal nerve infiltration (TV-PNI) technique and the ultrasound-guided transgluteal pudendal nerve infiltration (TG-PNI) technique.

Methods

Forty patients who underwent PNI for the diagnosis of PN were evaluated. Thirty-five of these 40 patients, who were diagnosed as PN, underwent a total of 70 further unilateral PNI. All the patients underwent PNI for twice after the first diagnostic PNI, 1 week apart.

Results

In the ultrasound (US)-guided TG-PNI group, the success rate was 68.8% (11 of 16) in both “pain in the sitting position” and “pain in the region from the anus to the clitoris.” The success rate of blocks in the US-guided TG-PNI group was 75% (12 of 16) in terms of pain during/after intercourse. In the finger-guided TV-PNI group, the success rate was 84.2% in both “pain in the sitting position” and “pain in the region from the anus to the clitoris.” The success rate of blocks in the fingerguided TV-PNI group was 89.5% (17 of 19) in terms of pain during/after intercourse. There was no statistically significant difference in the success rate of the 3 assessed conditions between the 2 groups (P>0.05).

Conclusions

The TV-PNI may be an alternative to US-guidance technique as a safe, simple, effective approach in pudendal nerve blocks.

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.

Fecal retention in childhood: Evaluation on ultrasonography

BACKGROUND

To assess the usefulness of rectal diameter measurement on ultrasonography as a diagnostic tool for fecal retention in children.

METHODS

One hundred children (median age, 5.0 years), consisting of 80 with functional constipation and 20 without constipation, participated in the study. All patients underwent physical examination that included digital rectal examination. Forty-five children underwent ultrasonography in three differential planes: transection above the symphysis; under the ischial spine; and at the bladder neck. The measurement of the rectal diameter at the transection above the symphysis could most easily detect fecal retention and had the closest correlations with retention among the three planes.

RESULTS

Rectal diameter was wider at all measuring points (35.2 vs 20.9 mm above the symphysis, P < 0.0001; 35.7 vs 24.0 mm under the ischial spine, P < 0.0001; and 19.4 vs 8.7 mm at the bladder neck, P < 0.0001) in children with fecal retention than in those with no fecal retention. With regard to presence of constipation, children with fecal retention had a wider rectal diameter above the symphysis than those with no fecal retention (children with functional constipation, 35.3 vs 20.0 mm, P < 0.0001; children without constipation: 32.6 vs 14.6 mm, P = 0.0026). The cut-off for the rectal diameter measured above the symphysis to identify fecal retention was 27 mm, with high sensitivity and specificity (95.5% and 94.1%, respectively).

CONCLUSION

Ultrasound rectal diameter measurement can be used to detect fecal retention in children.

Non-Invasive Targeted Peripheral Nerve Ablation Using 3D MR Neurography and MRI-Guided High-Intensity Focused Ultrasound (MR-HIFU): Pilot Study in a Swine Model

PURPOSE

Ultrasound (US)-guided high intensity focused ultrasound (HIFU) has been proposed for noninvasive treatment of neuropathic pain and has been investigated in in-vivo studies. However, ultrasound has important limitations regarding treatment guidance and temperature monitoring. Magnetic resonance (MR)-imaging guidance may overcome these limitations and MR-guided HIFU (MR-HIFU) has been used successfully for other clinical indications. The primary purpose of this study was to evaluate the feasibility of utilizing 3D MR neurography to identify and guide ablation of peripheral nerves using a clinical MR-HIFU system.

METHODS

Volumetric MR-HIFU was used to induce lesions in the peripheral nerves of the lower limbs in three pigs. Diffusion-prep MR neurography and T1-weighted images were utilized to identify the target, plan treatment and immediate post-treatment evaluation. For each treatment, one 8 or 12 mm diameter treatment cell was used (sonication duration 20 s and 36 s, power 160-300 W). Peripheral nerves were extracted < 3 hours after treatment. Ablation dimensions were calculated from thermal maps, post-contrast MRI and macroscopy. Histological analysis included standard H&E staining, Masson's trichrome and toluidine blue staining.

RESULTS

All targeted peripheral nerves were identifiable on MR neurography and T1-weighted images and could be accurately ablated with a single exposure of focused ultrasound, with peak temperatures of 60.3 to 85.7°C. The lesion dimensions as measured on MR neurography were similar to the lesion dimensions as measured on CE-T1, thermal dose maps, and macroscopy. Histology indicated major hyperacute peripheral nerve damage, mostly confined to the location targeted for ablation.

CONCLUSION

Our preliminary results indicate that targeted peripheral nerve ablation is feasible with MR-HIFU. Diffusion-prep 3D MR neurography has potential for guiding therapy procedures where either nerve targeting or avoidance is desired, and may also have potential for post-treatment verification of thermal lesions without contrast injection.

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.

Magnetic resonance neurography-guided nerve blocks for the diagnosis and treatment of chronic pelvic pain syndrome

Magnetic resonance (MR) neurography - guided nerve blocks and injections describe a techniques for selective percutaneous drug delivery, in which limited MR neurography and interventional MR imaging are used jointly to map and target specific pelvic nerves or muscles, navigate needles to the target, visualize the injected drug and detect spread to confounding structures. The procedures described, specifically include nerve blocks of the obturator nerve, lateral femoral cutaneous nerve, pudendal nerve, posterior femoral cutaneous nerve, sciatic nerve, ganglion impar, sacral spinal nerve, and injection into the piriformis muscle.

High-Resolution ultrasound of the pudendal nerve: normal anatomy

INTRODUCTION

In this study we aimed to determine whether high-resolution ultrasound (US) can identify the pudendal nerve and its terminal branches. We also attempted to identify the best approach for visualizing these structures.

METHODS

Normal anatomy of the pudendal nerve was evaluated in 3 cadavers and 20 healthy volunteers proximally at the level of the ischial spine and distally with low-frequency (2-5-MHZ) and high-frequency (12-7-MHZ and 17-5-MHZ) transducers. Two musculoskeletal radiologists performed the examinations and evaluations. Volunteers were placed in 3 different positions, which allowed different approaches (posterior, medial, and anterior transperineal). A 0-3 scale was used to assess nerve visibility.

RESULTS

Visualization of the pudendal nerve at the ischial spine was best when using a medial approach (P < 0.004); the terminal branches were seen best with the anterior approach (P < 0.002).

CONCLUSION

High-resolution ultrasound (US) can identify the pudendal nerve and its terminal branches.

Sonographically guided obturator internus injections: techniques and validation

OBJECTIVES

The primary purpose of this investigation was to describe and validate sonographically guided techniques for injecting the obturator internus (OI) muscle or bursa using a cadaveric model.

METHODS

A single experienced operator completed 10 sonographically guided OI injections in 5 unembalmed cadaveric pelvis specimens (4 female and 1 male, ages 71-89 years with body mass indices of 15.5-24.2 kg/m2). Four different techniques were used: (1) OI tendon sheath (4 injections), (2) OI intramuscular (2 injections), (3) OI bursa trans-tendinous (2 injections), and (4) OI bursa short-axis (2 injections). In each case, the operator injected 1.5 mL of diluted yellow latex using direct sonographic guidance and a 22-gauge, 87.5-mm (3½-in) needle. Seventy-two hours later, study coinvestigators dissected each specimen to assess injectate placement.

RESULTS

All 10 OI region injections accurately placed latex into the primary target site. Two of the 4 OI tendon sheath injections produced overflow into the underlying OI bursa. Both OI intramuscular injections delivered 100% of the latex within the OI. All 4 OI bursa injections (2 trans-tendinous and 2 short-axis) delivered 100% of the latex into the OI bursa, with the exception that 1 OI bursa trans-tendinous injection produced minimal overflow into the OI itself. No injection resulted in injury to the sciatic nerve or gluteal arteries, and no injectate overflow occurred outside the confines of the OI or its bursa.

CONCLUSIONS

The results of this investigation demonstrate that sonographically guided injections into the OI or its bursa are feasible and, therefore, may play a role in the diagnosis and management of patients presenting with gluteal and "retrotrochanteric" pain syndromes.

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.