Robotic-Assisted Resection of a Benign Schwannoma of the Obturator Nerve: A Rare Case

BACKGROUND Neurilemmomas are rare tumors derived from the Schwann cells that comprise the peripheral nerve sheaths. They have a slow growth and rarely display malignancy. Early diagnosis is rare, and the treatment consists by surgical resection. Although robotic-assisted surgery is commonly used for treating retroperitoneal diseases, there are few reports of resection of retroperitoneal and pelvic schwannoma through robotic-assisted surgery. In the present study, we reported a case of complete excision of a benign retroperitoneal schwannoma of the obturator nerve by robotic-assisted surgery. CASE REPORT A 51-year-old woman was referred by her gynecologist for left pelvic discomfort of a 3-month duration. The physical examination was normal, but a computerized tomography scan of the abdomen and pelvis showed an expansive pelvic lesion in the topography of the left iliac vessels, a hypodense contrast enhancement measuring 4.6×3.4 cm. Magnetic resonance imaging showed an extraperitoneal lesion located medially and inferiorly to the left external iliac vessels, with a size of 4.9×3.7 cm, and of probable neural etiology. Surgical resection of the tumor was recommended because of the diagnostic hypothesis of obturator nerve schwannoma. CONCLUSIONS This case showed that retroperitoneal neurilemmomas are difficult to diagnose owing to a lack of specific symptoms, and the best treatment is complete tumor resection. The use of robotic techniques gives greater dexterity to the surgeon, since it provides high-definition 3-dimensional vision, which can make the removal of retroperitoneal tumors susceptible to minimally invasive resection in a safe and effective way.

Effect of obturator nerve block during transurethral resection of bladder tumors on the disease recurrence, progression and surgery outcomes

OBJECTIVE

In our study, we aimed to evaluate the effect of the obturator nerve block (ONB) on the operation time, duration of hospital stay, complete resection, presence of muscle tissue in the pathology, second resection, recurrence, and progression, when applied in addition to spinal anesthesia in patients with primary bladder lateral wall tumor and Transurethral Resection of Bladder Tumor (TURBT) was planned.

MATERIALS AND METHODS

Seventy patients with bladder lateral wall tumors were included in the study. In addition, ONB was applied to 35 of the patients who underwent spinal anesthesia. The two groups were compared in terms of obturator reflex development, perforation, complete resection, presence of muscle tissue in pathology samples, need for second resection, need for second resection due to inadequate muscle tissue, and 1 year recurrence and progression rates.

RESULTS

When the two groups were compared for obturator reflex and bladder perforation, both were found to be lower in the ONB group (p = 0.002, p = 0.198, respectively). The rate of complete resection and the presence of muscle tissue in the pathology samples were higher in the ONB group (p = 0.045, p = 0.034, respectively). The rates of second resection and second resection due to inadequate muscle tissue were found to be higher in the group without ONB (p = 0.015, p = 0.106, respectively). In the 1-year follow-up, the recurrence rate was significantly lower in the ONB group (p < 0.001), while there was no significant difference between the progression rates (p = 0.106).

CONCLUSION

In our study, we found out that ONB applied in addition to spinal anesthesia increases the rate of complete and muscle tissue resection by decreasing the obturator reflex, and causes a significant reduction in the need for second resection and tumor recurrence.

Uterine Fibroid-Induced Compressive Neuropathy of Lumbar Plexus and Obturator Nerve

Introduction

Uterine fibroids are the most common gynecologic tumors in reproductive-aged women with a prevalence of up to 80%. Symptoms can range from heavy vaginal bleeding and bulk symptoms to, less frequently, deep vein thrombosis and bowel obstruction.

Case Description

A 32-year-old female patient presented with acute-onset of right groin and knee pain, and difficulty ambulating. A large posterior uterine fibroid was found to be compressing branches of the lumbar plexus, including the obturator nerve. The patient underwent gynecologic evaluation and an urgent laparoscopic myomectomy. Postoperatively, she had significant improvement in neurologic symptoms. She continued physical therapy for residual mild paresthesia and pain with prolonged ambulation.

Discussion

Large pelvic masses such as uterine fibroids should be considered on the differential diagnosis for acute-onset non-gynecologic symptoms such as compressive neuropathy, which require urgent evaluation and possible surgical management.

Increased Plasma Ignition Distance Practice may Prevent the Obturator Reflex Occurrences and Compare of its Effectiveness Versus Obturator Block: A Prospective, Randomized, Controlled Study

OBJECTIVE

To compare the ability of the obturator nerve block (ONB) and increased plasma ignition distance practice (IPDP) techniques to inhibit obturator nerve reflex (ONR) occurring with bipolar transurethral resection of the bladder.

METHODS

Sixty patients who had a tumor placed at the lateral sidewall or had a tumor in another part of the bladder along with the lateral wall were randomly enrolled. Cystoscopic and ultrasonographic examinations and a computerized tomography scanning of the urinary bladder were used to determine the ONB side. Group 1 consisted of patients who had the ONB procedure. Group 2 consisted of patients who had IPIDP. The severity of the ONR was classified as severe, mild, and very mild. The study's primary endpoint was ONR occurrences and successful completion of the surgery. The secondary endpoints were bleeding and bladder perforation.

RESULTS

There was a significant difference in the occurrence of ONR between the two groups (P = 0.0011). However, there was no significant difference between the two groups in the ability to resect the tumor and complete the surgery (P = .764). There was no correlation between the ONR and the tumor size (P = 0.478).

CONCLUSION

Our study concluded that both ONB and IPIDP have comparable results, especially in resecting tumors and completing the operation. IPIDP has some advantages over ONB, such as shorter operative time, lower total costs, and less trained personnel requirements.

Outcome of transurethral resection of bladder tumour under spinal anaesthesia combined with obturator nerve block in Sri Lanka

Purpose:

Transurethral resection of bladder tumour (TURBT) is done under general anaesthesia (GA) with muscle relaxation to prevent obturator jerk and bladder perforation. TURBT under spinal anaesthesia (SA) with obturator nerve block (ONB) may prevent the obturator jerk while eliminating the disadvantages of GA.

Objectives:

To assess the outcome of TURBT under SA and ONB.

Methods:

Patients undergoing TURBT for lateral wall tumours from 01.11.2017 to 30.10.2020 were prospectively studied. Anterior branch of obturator nerve with plain Bupivacaine was blocked with the guidance of an ultrasound scan and a nerve stimulator. Significant obturator jerk which necessitated conversion to GA was defined as failed ONB.

Results:

Out of 72 patients with mean age of 66.7 years underwent ONB, 61 (84.7%) were men. Fifty two (72.2%) had unilateral and 20 (27.8%) had bilateral blocks. Sixty one (84.7%) patients had no obturator jerk whereas 5 (7%) had a mild jerk which did not preclude safe resection. Six patients (8.3%) had a failed ONB requiring conversion to GA. None had a bladder perforation requiring laparotomy, developed neurovascular injury or anaesthetic toxicity and only one patient required intensive care monitoring.

Conclusion:

SA with anterior branch of ONB is an effective and safe alternative to GA with muscle relaxation for TURBT although a randomized trial is necessary to determine the true efficacy and safety over the other.

Systematic Review and Meta-Analysis of Inguinal Versus Classic Obturator Nerve Block

Obturator nerve block (ONB) has been widely applied in transurethral resection of bladder tumor and knee surgery to prevent serious complications such as bladder perforation or to improve the quality of anesthesia during knee surgery. The classic/pubic and inguinal ONB methods are the two primary approaches used. The classic and inguinal ONB methods are two techniques for anesthetizing the obturator nerve, and each method may result in different respective outcomes. We aimed to compare the efficacy of the classic and inguinal methods. We presumed the inguinal approach to be an overall superior technique because it was recently invented and has been reported to provide numerous benefits. This study included randomized controlled trials comparing classic and inguinal approaches to ONB. Two independent investigators extracted study-level data for a random-effects meta-analysis of the comparison between the classic approach and inguinal approaches. We identified five studies comprising 312 patients. The pooled results revealed a higher success rate (risk ratio, 1.15; 95% confidence interval [CI], 1.04-1.27), fewer puncture attempts (mean difference, -0.84; 95% CI, -1.55 to -0.12), and shorter procedure time (mean difference, -28.87; 95% CI, -47.19 to -10.54) for patients given inguinal ONB. The inguinal approach is, overall, the superior method for performing the ONB procedure. The inguinal method resulted in a higher success rate, fewer puncture attempts, and shorter procedure time.

Effect of FK506 administration after obturator nerve injury: a functional and ultrastructural study

The frequency of obturator nerve damage due to pelvic diseases, fractures or gynecologic procedures is uncertain. In the present study, we investigated the effect of FK506, a potent macrolide antibiotic and immunosuppresant, on obturator nerve recovery at morphological and functional levels. Forty female Wistar rats were randomly divided into four groups (control, sham, FK506-treated, vehicle-treated). In half of animals (FK506-treated and vehicle-treated) an obturator nerve crush (30 seconds clamp) was created. In FK506-treated group FK506 administration (1 mg/kg/day, subcutaneously) was performed on each postoperative day. All the rats were functionally evaluated by pinch and adduction tests preoperatively and postoperatively at one, two, three and four weeks after nerve injury. On the 28th postoperative day obturator nerve samples were collected and analyzed qualitatively by light and electron microscopy. FK506 treatment resulted in dramatic improvement in nerve function and in the ultrastructure of nerve fibers suggesting its therapeutic potential in traumatic obturator nerve injury.

Transobturator tape: variation in the vascular anatomy of the obturator foramen

AIMS

1) To describe the anatomy of the obturator canal and variations in placement of the obturator nerve, artery and vein and 2) To record the proximity of these structures to the optimal point of placement of the transobturator tape (TOT) trochar.

METHODS

Eighteen obturator foramens were dissected in nine female cadavers. The obturator nerve, artery and vein were exposed as they entered the foramen. Orientation of the obturator nerve, artery and vein from medial to lateral were recorded. Obturator arterial and venous branches > 1 mm crossing the obturator membrane were noted. Usual placement of the TOT trochar as it passes through the obturator membrane to the obturator canal was determined and the distance from the trochar to each of the structures was recorded.

RESULTS

The medial to lateral orientations of the obturator nerve, artery and vein are variable where these structures enter the obturator canal. The vein appeared most medially in 78% of cadavers and the artery in 22%. The nerve was located most lateral in all cases. Venous (22%) and arterial (17%) branches of the obturator vessels traversed medially across the obturator membrane towards the side of trochar placement. The mean distance from optimal trochar placement to the obturator canal was 30 mm.

CONCLUSIONS

The anatomy of the obturator foramen is not consistent. The proximity of the obturator canal to the TOT trochar, the medially crossing obturator nerve, artery and vein and their branches, as well as their variable orientation in the canal should be considered when performing the transobturator tape procedure.

Obturator neuropathy complicating elective laparoscopic tubal occlusion

Isolated obturator neuropathy is rare. We report a woman who developed a severe obturator neuropathy from electrocautery during elective laparoscopic tubal ligation. This complication has not previously been described in association with the procedure, and the potential etiological role of an underrecognized anatomical variant, in which an accessory obturator nerve is present, is discussed.

Myofasciitis and polyneuritis related to Buprenorphine abuse

Various kinds of neuromuscular manifestations are known with the recreational drugs. We report an interesting case of extensive myositis and fasciitis of thigh following an injection of a solution of Buprenorphine. The inflammatory process affected the sciatic and obturator nerve as well.

[Neuropathy of the obturator nerve as a source of pain in soccer players]

Chronic inguinal and lower abdominal pain in high-performance athletes is common and often disabling problem. Diagnose and treatment is often difficult due to many anatomic structures in the inguinal and groin region that have the potential to cause pain. We report 52 cases of a chronic groin pain in soccer players due to fascial entrapment of the obturator nerve. All patients presented clinical symptoms and signs of post exercise groin, lower abdominal or medial tight pain and adductor muscles weakness and paresthesia in cutaneous distribution of medial thigh. Except clinical signs in the diagnosis of obturator neuropathy we used diagnostic local anaesthetic block and electromyography. In 52 patients the cause of chronic groin pain was obturator neuropathy and they were treated operatively. Surgical neurolysis provided the definitive cure of pain in 41 players.

Postpartum obturator neurapraxia. A case report

BACKGROUND

Obturator nerve injury is a rare complication of vaginal delivery.

CASE

Postpartum obturator neurapraxia was clinically diagnosed in a 22-year-old woman on the first postpartum day after a vaginal delivery. With physical therapy, the neurologic symptoms resolved by the third postpartum month.

CONCLUSION

Maternal nerve injuries are uncommon in obstetrics. The diagnosis of obturator neurapraxia is usually made clinically. The symptoms will resolve with conservative physical therapy alone in the majority of cases.

Effect of lithotomy positions on strain of the obturator and lateral femoral cutaneous nerves

The purpose of this study was to determine if various lithotomy positions increase strain on the obturator and lateral femoral cutaneous nerves in fresh adult cadavers. A static load cell was used to record strain changes of the obturator and lateral femoral cutaneous nerves in the pelvis and anterior thigh when the lower limbs were placed in three sets of positions of varying hip abduction and flexion. The means of the strain measurements, which were measured in grams in all positioning angles were compared to the baseline 0 degrees measurements. Analysis of variance was calculated for the differences. Flexion of the hip did not increase strain on either nerve. Abduction to 30 degrees or 45 degrees increased strain by more than 30 g on the obturator nerve (P < 0.05) but not the lateral femoral cutaneous nerve. The addition of 45 degrees or more of flexion to abduction negated the strain increase on the obturator nerves seen with abduction alone. Nerve strain >30 g has been associated consistently with nerve dysfunction, disrupting axonal transmission, and causing structural neural damage. Our findings suggest that concomitant hip flexion should be used when placing anesthetized patients in a lithotomy position that includes abduction of the lower limbs to >30 degrees to decrease the risk for perioperative neuropathy of the obturator nerve.

Obturator neuropathy: causes and outcome

To study causes of obturator neuropathy and to correlate them with outcome, we retrospectively studied patients seen at the Mayo Clinic electromyography (EMG) laboratory from 1975 through 1999 with a diagnosis of obturator neuropathy. Twenty-two patients with obturator neuropathy were identified. The clinical outcome of patients with acute obturator neuropathy treated conservatively was good regardless of etiology or severity.

Results of termino-lateral neurorrhaphy to original and adjacent nerves

In this comprehensive investigation, we studied three different neurorrhaphy models in an attempt to elucidate the potential of termino-lateral nerve repair to original and adjacent nerves. In experimental group 1, the peroneal nerve was sectioned and then attached to the posterior tibial nerve in a termino-lateral fashion. In experiment group 2, the motor nerves to the gastrocnemius muscle were sectioned and then attached to the posterior tibial nerve in a termino-lateral fashion. In experimental group 3, the obturator nerve (L2-4) was sectioned and attached to the sciatic nerve (L4-6) in a termino-lateral fashion. For the control in each group, the same type of nerve used in each respective group was transected without repair. Experimental groups 1 and 2 showed viable axons in the peroneal nerve distal to the neurorrhaphy site. Experimental group 3 showed no viable axons at these sites. No regeneration was observed in the transected nerve without repair in all three control groups. This study suggests that termino-lateral neurorrhaphy is a viable means of repairing damaged nerves if the distal segment of the sectioned nerve is reattached to its original trunk distal to its original branch point. However, the results from experimental group 3 demonstrate that termino-lateral neurorrhaphy cannot be used to repair nerves when the donor and recipient nerves originate from different spinal cord levels.

Mechanoreceptors in collateral knee ligaments: an animal experiment

The mechanoreceptors in the collateral ligaments of the knee joint in rat hindlimbs were studied. In group II (n=10) the femoral and obturator nerves were sectioned. In both groups III and V (n=20) the sciatic nerve was sectioned. In group V (n=10) the sectioned sciatic nerve was sutured 4 weeks after sectioning. In group IV (n=10) all three nerves were sectioned. Group I (n=10) served as control. After 4 months all animals were killed. The ligaments of the knee joint were preserved and stained with gold chloride, paraffin-embedded and cut in sagittal serial sections. The results showed that 4 months after partial or total denervation of the limb, there was necrosis and a decrease in the number of mechanoreceptors, which was dependent upon the severity and site of the lesion. After suture of the sciatic nerve the increase in mechanoreceptors suggested a regenerative process.

Benign schwannoma of the obturator nerve: a case report

We describe a schwannoma of the obturator nerve in a woman 66 years old. It was diagnosed only postoperatively because of the aspecificity of the symptoms. The difficulty of making a correct diagnosis during surgery is discussed, and the potential serious consequences of total excision of the nerve are described.

[Schwannoma of the obturatorius nerve as differential diagnosis in cystic adnexa tumors]

We report on a case of benign retroperitoneal schwannoma involving the obturator nerve. Discussing the difficulties of diagnosis and treatment the following became clear: 1.) Clinical examination, ultrasound and computed tomography are not helpful to differentiate a retroperitoneal schwannoma from a cystic ovarian tumour; this problem can perhaps be overcome by MR imaging. 2.) The diagnosis should be borne in mind in cases of retroperitoneal tumours of unclear origin. Appropriate surgery is necessary to avoid nerve damage and paralysis.

The "critical zones" of entrapment of the nerves of the lower limb

The author has studied, in a group of 40 dissections on cadavers of individuals of different ages, the main "critical zones" of entrapment of some terminal branches of the lumbo-sacral plexus, which include canals (fibrous, osteo-fibrous, fibro-muscular), intervals (intermuscular, fibro-muscular, musculo-ligamentous), rings (fibrous or fibro-muscular) and foramina. They provide the topographical anatomical basis for possible compressive phenomena of the nerves of the lower limb.

Obturator hernia

Obturator hernias are relatively rare. In the past 15 years at the Mayo Clinic, eight patients underwent nine operations for repair of 11 obturator hernias, which represented 0.073 per cent (11 of 15,098) of all hernias repaired at this institution. Elderly women with chronic disease were most frequently affected. Symptoms were usually intermittent; mechanical small intestinal obstruction was the most common presenting condition, followed by pain in the thigh or groin area. The Howship-Romberg sign was found in only two patients, and a correct preoperative diagnosis was made in only one patient. Midline abdominal incisions were made in all patients. Incarcerated ileum was the most frequently encountered organ in the hernia sac. Surprisingly, foci of endometriosis in the obturator defect accounted for symptoms in two patients with three obturator hernias. Right-sided obturator hernias outnumbered left, and bilateral obturator hernias were found synchronously in two instances and metachronously in one instance. The often debilitated state of the patients with obturator hernia and the frequent delay of diagnosis combined to produce significant operative morbidity and mortality rates.

Surgical and anatomic study of calving paralysis

Dissections of the bovine pelvic inlet region were made to determine which nerves were vulnerable to fetal-induced traumatic damage. Surgical sections of the obturator nerves and the lumbar roots of the sciatic (ischiatic) nerves were done to determine a possible cause of calving paralysis. Only 1 of 11 cattle in which bilateral obturator nerve section was done was unable to stand after the operation, and in this individual, secondary stifle injuries were found on necropsy. Subsequent surgical operations were performed on some of these cattle in order to section the lumbar root of the sciatic nerve. Of 6 cattle prepared, 2 were unable to rise after surgery and another 2 became "downer" cattle after 30 to 45 minutes of forces exercise. Also, some of these cattle were very ataxic and had intermittent fetlock flexion.