Comparison of different methods of obturator nerve block in transurethral resection of bladder tumors: A systematic review and network meta-analysis.

BACKGROUND: Bladder cancer is the most common malignancy of the urinary system, and accounts for 3% of newly diagnosed tumors. Transurethral resection of bladder tumor plays a key role in treating bladder cancer, among which one of the most serious complications is bladder perforation caused by obturator nerve reflex. Obturator nerve reflex can be prevented by inducing obturator nerve block after lumbar anesthesia. However, No study so far has compared the inhibitory effect of different obturator nerve block approaches on intraoperative obturator nerve reflex and bladder perforation. METHOD: In this study, we conducted a network meta-analysis (NMA) of studies comparing the efficacy of different obturator nerve block approaches performed after lumbar anesthesia in operation. RESULT: The distal obturator nerve block guided by peripheral nerve stimulator is the best approach for preventing obturator reflex. The proximal obturator nerve block guided by ultrasound is the best approach for preventing bladder perforation. CONCLUSION: Spinal anesthesia combined with the distal obturator nerve block guided by peripheral nerve stimulator is the most optimal approach to prevent the obturator nerve reflex. But the doctor should choose the appropriate anesthesia method according to the patient's general condition, tumor location, and doctor's proficiency in puncture techniques.

A Prospective Study to Compare Analgesia from Femoral Obturator Nerve Block with Fascia Iliaca Compartment Block for Acute Preoperative Pain in Elderly Patients with Hip Fracture.

BACKGROUND This study aimed to compare femoral obturator nerve block (FONB) with fascia iliaca compartment block (FICB) in the management of acute preoperative pain in elderly patients with hip fracture. MATERIAL AND METHODS Patients ≥65 years (n=154) diagnosed with hip fracture who had surgery within 48 hours of hospital admission included two groups who received ultrasound-guided nerve block, the FONB group (n=77), and the FICB group (n=77). The visual analog scale (VAS) score for pain, requirement for analgesic drugs, nursing care requirements after hospitalization, post-operative complications, and rehabilitation were compared between the FONB and FICB patient groups. RESULTS The VAS scores after both nerve block procedures were significantly reduced compared with those before both nerve block procedures (P<0.05), but there were no differences on the second day after nerve block. The VAS scores at rest and on exercise in the FONB group were significantly lower than those in the FICB group at 30 min and one day after nerve block (P<0.05). The requirement for postoperative analgesic drugs in the FONB group was significantly lower than that in the FICB group (P=0.048). The incidence of nausea and vertigo in the FICB group were significantly higher than in the FONB group (P=0.031 and P=0.034, respectively). Patients in the FONB group experienced significantly improved quality of postoperative function (P=0.029). CONCLUSIONS Both FONB and FICB provided pain control for elderly patients with hip fracture. However, compared with FICB, FONB resulted in significantly improved analgesia with a reduced requirement for analgesic drugs.

Use of ultrasound and fluoroscopy guidance in percutaneous radiofrequency lesioning of the sensory branches of the femoral and obturator nerves.

Hip pain is a common condition that is often seen in patients with multiple comorbidities. Often surgery is not an option due to these comorbidities. Percutaneous radiofrequency lesioning of the articular branches of the obturator and femoral nerves is an alternative treatment for hip pain. Traditionally, fluoroscopy is used to guide needle placement. We report a case where a novel approach was used with ultrasound guidance to visualize vascular and soft tissue structures in real time. The use of ultrasound might help to guide the needle to avoid vascular complications due to anatomical variation between patients.

[Effect of continuous femoral nerve catheter length on blockade of femoral nerve, lateral femoral cutaneous nerve and obturator nerve].

OBJECTIVE: To assess the effects of length of continuous femoral catheter on blockade of femoral nerve, lateral femoral cutaneous nerve and obturator nerve. METHODS: In the study, 70 patients with American Association of Anesthesiologist grades I-II undergoing total knee arthroplasty were randomly divided into three groups, femoral nerve catheters were inserted 5 cm, 10 cm or 20 cm with assistance of a nerve stimulator, patient-controlled analgesia pumps were connected after load of 30 mL 0.3% ropivacaine via the catheters. Sensory blockade of the femoral nerve, lateral femoral cutaneous nerve and obturator nerve were recorded at 24 h postoperatively. Visual analog scale (VAS) pain scores during rest and motion were recorded at 24 h and 48 h postoperatively. RESULTS: The blockade effect of lateral femoral nerve in the 20 cm group was the best. There was no significant difference in sensory blockade between the 5 cm group and the 10 cm group. There was no significant difference in VAS score among the three groups. CONCLUSION: When continuous femoral nerve block is used for postoperative analgesia after total knee arthroplasty surgery, the catheters that are inserted 5 cm, 10 cm or 20 cm could provide similar and satisfying analgesia effect.

The parasacral sciatic nerve block does not induce anesthesia of the obturator nerve.

PURPOSE: The ability of the parasacral sciatic nerve block (PSNB) to induce anesthesia of the obturator nerve remains controversial. Our objective was to evaluate the anesthesia of the obturator nerve after a PSNB. METHODS: Forty patients scheduled to undergo knee surgery (anterior cruciate ligament reconstruction) were included in this prospective, randomized, controlled study. Patients were randomized to receive PSNB alone (control group, n = 20) or PSNB in combination with an obturator nerve block (obturator group, n = 20). After evaluation for 30 min, the two groups received a femoral nerve block, and patients were taken to surgery. The obturator nerve blockade was assessed by measurement of adductor strength at baseline (T0) and every 10 min during the 30-min evaluation (T10, T20, and T30). Pain scores after tourniquet inflation and during surgery were compared between the two groups. The requirement for additional intravenous analgesia and/or sedation was also recorded. RESULTS: The two groups had comparable demographic and surgical characteristics. Four patients were excluded from the study because of PSNB or femoral nerve block failure. The adductor strength values were similar between groups at T0 but were significantly lower in the obturator group at T10, T20, and T30 (p < 0.0001). Patients in the obturator group reported less pain than those in the control group (p < 0.05). They also required less additional intravenous sedation and/or analgesia (p < 0.05). CONCLUSION: This clinical study demonstrated that the PSNB is an unreliable means of inducing anesthesia of the obturator nerve and emphasizes the need to block this nerve separately to induce adequate analgesia during knee surgery.

Regeneration and functional recovery of intrapelvic nerves removed during extensive surgery by a new artificial nerve conduit: a breakthrough to radical operation for locally advanced and recurrent rectal cancers.

PURPOSE: In the current strategy against locally advanced and recurrent rectal cancers possibly involving intrapelvic nerves, there has been a serious dilemma between extensive surgery and limited surgery. The former can attain high tumor curability by sacrificing the nerve functions while the latter prioritizes the patient quality of life by preserving the nerve functions but with a compromised curability. Here we present a new surgical strategy for locally advanced and recurrent rectal cancers, which realize both high tumor curability and good quality of life. METHODS: A new artificial nerve conduit (polyglycolic acid collagen tube) developed by in site tissue engineering technology was applied to recovery the disturbed functions after removing the nerves from 11 patients undergoing extensive surgery for intrapelvic advanced or recurrent colorectal cancers. The reconstructed nerves included eight autonomic nerves which are essential for the genitourinary function and three somatic nerves which control the sensation and mobility of the legs. RESULTS: Out of ten cases followed up more than 2 years and evaluated fully, eight including two report cases showed a functional recovery of the disturbed autonomic and somatic nerves clinically. The nerve function started to recover from 3 to 6 months after the operation and continued to improve with times. No specific complications associated with the nerve repair have been noted. CONCLUSIONS: The new strategy utilizing the nerve conduit can be a breakthrough in radical operations for locally advanced and recurrent rectal cancers to resolve the problems between tumor curability and the patient quality of life.

Obturator nerve transfer as an option for femoral nerve repair: case report.

OBJECTIVE: Nerve transfers have proved to be an important addition to the armamentarium in the repair of brachial plexus lesions, but have been used sparingly for lower extremity nerve repair. Here, we present what is believed to be the first description of a successful transfer of the obturator nerve to the femoral nerve. CLINICAL PRESENTATION: A 45-year-old woman presented with a complete femoral nerve lesion after removal of a large (15-cm) schwannoma of the retroperitoneum involving the lumbar plexus. INTERVENTION: The obturator nerve was transferred to the distal stump of the femoral nerve in the retroperitoneal space at the inguinal ligament three months post-injury. At 2 years post-repair, the patient demonstrated 4 out of 5 return (Medical Research Council grade) of quadriceps function and was able to walk nearly normally. CONCLUSION: In cases in which there are extensive gaps in the femoral nerve, transfer of the obturator nerve provides an option to traditional nerve graft repair.

Withdrawal reflexes in adductor muscles elicited by electrical and magnetic stimulation of the obturator nerve.

The withdrawal reflex in the short head of the biceps femoris muscle after electrical stimulation of the sural nerve at the ankle has been investigated in numerous studies. These studies have described two distinct responses: early (R-II) and late (R-III). However, withdrawal reflex activity of the adductor muscles in the legs has not been studied systematically. Adductor muscle reflex activity is important because it can produce serious clinical problems, such as adductor spasticity and spasms, during bladder surgery. The present study examined withdrawal reflex features of adductor muscles obtained by electrical and magnetic stimulation of the obturator nerve (ON) in 34 normal healthy subjects. Early adductor muscle withdrawal reflex responses were elicited by ipsilateral ON electrical stimulation with a mean latency of 45.7+/-2.0 ms (responses in 94% of subjects). Reflex responses were also obtained using magnetic stimulation at a similar incidence rate. Contralateral ON electrical stimulation resulted in a similar reflex, but with a lower incidence. ON and femoral nerve electrical and magnetic coil stimulation produced similar low-incidence responses in the vastus medialis. These findings indicate that short latency adductor withdrawal reflexes are easily obtained on both sides following electrical or magnetic stimulation of the ON, and they can be elicited by both nociceptive and nonnociceptive stimuli. These reflexes prepare the body for a proper response to incoming signals and likely serve to protect the pelvic floor and pelvic organs.

[Electrophysiological study on motor nerve implantation after ectopic transplantation of skeletal muscle in rat].

OBJECTIVE: To study the effect of motor nerve implantation after ectopic transplantation of skeletal muscle on nerve regeneration in rat. METHODS: Sixty Sprague-Dewley male 8-monthold rats were randomly divided into 3 groups: control group, in situ implantation group and ectopic transplantation group. In control group, obturator nerve controlling right gracilis was cut off. In in situ implantation group, the right gracilis was cut off and replanted to its original site, and the obturator nerve was implanted to the muscle. In ectopic transplantation group, the right gracilis was cut off and transplanted to the muscle of the left leg, and the obturator nerve was implanted to the muscle. After 25 weeks, the neurophysiological information was collected through electromyography and the weight of the muscle was measured. RESULTS: The potential without control of the nerve existed in control group. There were no significant differences in latency, amplitude and conduct velocity between in situ implantation group and ectopic transplantation group (P > 0.05). The atrophy of gracilis was dominant in control group, the weight of the muscle was 158.0 +/- 19.3 mg. The weights of the muscle were 509.6 +/- 14.5 mg in ectopic transplantation group and 516.8 +/- 12.7 mg in in situ implantation group, showing no significant difference (P > 0.05). The weights of the muscle in in situ implantation and ectopic transplantation group were larger than that in control group, showing significant difference (P < 0.05). CONCLUSION: Motor nerve implantation after ectopic transplantation of skeletal muscle could prevent the atrophy of the muscle and resume partial function of nerve.

[Transurethral resection in saline (TURis): a newly developed TUR system preventing obturator nerve reflex].

PURPOSE: We developed an innovative transurethral resection system (TURis) consisting of a uniquely-designed generator and a resectoscope. The obturator nerve is protected from troublesome reflexes during TURis because the high frequency current delivery route is via the resection loop to the sheath of the resectscope and not via a patient plate. After extensive preclinical evaluation and verification of the system using an animal model to ensure efficacy as well as operational safety, TURis was conducted for treatment of superficial bladder cancer and benign prostatic hyperplasia. MATERIALS AND METHODS: In preclinical experiments swine bladder wall was transurethrally resected using the system in a saline environment. The results were compared with data obtained from an identical resection using the conventional system using sorbitol solution irrigation. Electrolytic contents were measured after TUR for comparative evaluation vis-a-vis corresponding pre-TUR data. Also, the depth of heat degeneration was measured in the resected tissue. From December, 2000 to June, 2002, TURis was performed in 25 cases of superficial bladder cancer and 30 cases of benign prostatic hyperplasia (BPH), using saline irrigation. All 55 cases were performed under spinal anesthesia without an obturator nerve block. The output power was set at 280 W for cut and 120 W for coagulation. A smaller electrode than those used in conventional TUR was used to improve the cutting efficacy. Occurrence of obturator nerve reflexes, difference of hematocrit and electrolytic contents before and after TURis, operation time and total volume of irrigated saline were evaluated. RESULTS: TURis in animal model: No adductor contraction of a lower limb was observable except for minimal creeping during the resection of a site close to the urethra. There were no apparent anomalies relative to the blood electrolyte content after TURis. No difference was observed in the mean depth of heat-degeneration tissue change compared with the conventional system. TURis for bladder cancer and BPH: No additional skills were required for TURis compared to conventional TUR. No obturator nerve reflex was observed except for a clinically insignificant thigh movement in one case of bladder cancer. The post-TURis blood tests manifested no significant anomalies in blood electrolyte content. Mean operation time for bladder cancer and BPH were 32 and 42 minutes respectively. Mean volumes of saline consumed during TURis were 6,083 ml for bladder cancer and 16,100 ml for BPH. CONCLUSIONS: TURis worked effectively in a saline-irrigated environment. It does not need a patient plate and obturator nerve block even in cases of bladder cancer on the lateral wall. In addition, saline was both safe and cost-effective compared to non-electrolytic solution as irrigant for TUR of BPH. This suggests that TURis may have more applications than conventional TUR.

An evaluation of the cutaneous distribution after obturator nerve block.

UNLABELLED: In 1973, Winnie et al. introduced the inguinal paravascular three-in-one block, which allegedly provides anesthesia of three nerves--the femoral, lateral cutaneous femoral, and obturator nerves--with a single injection. This concept was undisputed until the success of the obturator nerve block was reassessed by using evidence of adductor weakness rather than cutaneous sensory blockade, the latter being variable in its distribution and often absent. We performed this study, therefore, to evaluate the area of sensory loss produced by direct injection of local anesthetic around the obturator nerve. A selective obturator nerve block with 7 mL of 0.75% ropivacaine was performed in 30 patients scheduled for knee surgery. Sensory deficit and adductor strength were evaluated for 30 min by using sensory tests (cold and light-touch perception) and the pressure generated by the patient's squeezing a blood pressure cuff placed between the knees. Subsequently, a three-in-one block was performed, and the sensory deficit was reassessed. The obturator nerve block was successful in 100% of cases. The strength of adductors decreased by 77% +/- 17% (mean +/- SD). In 17 patients (57%), there was no cutaneous contribution of the obturator nerve. The remaining 7 patients (23%) had an area of hypoesthesia (cold sensation was blunt but still present) on the superior part of the popliteal fossa, and the other 6 (20%) had sensory deficit located at the medial aspect of the thigh. The three-in-one block resulted in blockade of the lateral aspect of the thigh in 87% of cases, whereas the anteromedial aspect was always anesthetized. By use of magnetic resonance imaging in eight volunteers, we demonstrated that the obturator nerve has already divided into its two branches at the site of local anesthetic injection. However, the injection of blue dye after having simulated the technique in five cadavers showed that the fluid regularly spread to both branches. We conclude that after three-in-one block, a femoral nerve block may have been assessed as an obturator nerve block in 100% of cases when testing the cutaneous distribution of the obturator nerve on the medial aspect of the thigh. IMPLICATIONS: Previous studies reporting an incidence of obturator nerve block after three-in-one block may have mistaken a femoral nerve block for an obturator nerve block in 100% of cases when the cutaneous distribution of the obturator nerve was assessed on the medial aspect of the thigh. The only way to effectively evaluate obturator nerve function is to assess adductor strength.

Percutaneous radiofrequency lesioning of sensory branches of the obturator and femoral nerves for the treatment of hip joint pain.

BACKGROUND AND OBJECTIVES: The sensory innervation of the hip joint includes the sensory articular branches of the obturator and femoral nerves. In this report, we retrospectively evaluated 14 cases in which hip joint pain was treated by percutaneous radiofrequency lesioning of sensory branches of obturator and/or femoral nerves. METHODS: Fourteen patients who had hip joint pain and underwent percutaneous radiofrequency lesioning of sensory branches of obturator and/or femoral nerves were studied. In all cases, intra-articular hip joint block or articular branch block of obturator nerve with local anesthesia was transiently effective. Radiofrequency lesioning was performed at 75 degrees C to 80 degrees C for 90 seconds using an RFG-3B generator and Sluijter-Mehta cannulae kit (Radionics, Burlington, MA) for the obturator nerve in 9 patients and for both the obturator and femoral nerves in 5 patients. To assess pain intensity, a visual analog scale (VAS) was used. RESULTS: The VAS scores before and after the radiofrequency lesioning were 6.8 +/- 0.9 and 2.7 +/- 1.3, respectively. Twelve patients (86%) reported at least 50% relief of pain for 1 to 11 months. There were no side effects or motor weakness observed. CONCLUSIONS: Percutaneous radiofrequency lesioning of sensory branches of the obturator and femoral nerves is an alternative treatment in patients with hip joint pain, especially in those where operation is not applicable.

[Elimination of the obturator reflex as a specific indication for dilute solutions of etidocaine. A study of the suitability of a local anesthetic for reflex elimination in the 3-in-1 block technic]. / Die Ausschaltung des Obturatorius-Reflexes als spezifische Indikation für verdünnte Etidocain-Lösungen. Eine Untersuchung zur Eignung des Lokalanaesthetikums für die Reflex-Elimination in der Technik des "3-in-1 blocks".

Direct stimulation of the obturator nerve by the electroresectoscope during transurethral resection of tumors in lateral bladder regions is possible under regional or general anaesthesia without muscle relaxation. The resulting obturator reflex may lead to perforation of the bladder. Two different regional techniques can be used to interrupt the obturator reflex arc: (1) separate block of the obturator nerve; or (2) the "3-in-1 block" (Winnie). In the present study elimination of the obturator reflex was carried out by "3-in-1 block" with diluted solutions of etidocaine in 55 cases. Venous plasma levels of etidocaine were measured in 9 patients after application of etidocaine 0.5% (unilateral 30 ml and bilateral 60 ml). Samples were taken 10, 20, 30, 40, 60, and 120 min after the "3-in-1 block". RESULTS. The "3-in-1 block" with diluted etidocaine produced excellent motor block of the obturator nerve. Clinical side effects did not occur. Plasma peak levels reached 2.2 micrograms/ml; the protein binding rate was 85%-95%. DISCUSSION. Elimination of the obturator reflex is the only specific motor nerve block in anesthesia. Diluted etidocaine solutions seem to be adequate: irrespective the technique used for eliminating the reflex, diluted etidocaine produces a good effect and permits a dosage reduction compared with other local anesthetics. It is possible to block the obturator nerve bilaterally by "3-in-1 block" or unilaterally by "3-in-1 block" in combination with epidural analgesia within the recommended dose limits.

Prevention of obturator nerve stimulation during transurethral surgery.

The obturator nerve passes in close proximity to the inferolateral bladder wall, bladder neck and lateral prostatic urethra. During a transurethral operation resection in these areas may result in stimulation of the obturator nerve, causing violent adductor contraction and possible inadvertent bladder perforation. To block this reaction d-tubocurarine and succinylcholine can be used during general anesthesia. However, it often is preferable to use spinal anesthesia during transurethral operations. Local anesthetic blockade of the obturator nerve as it passes through the obturator canal if effective for adductor spasm during spinal anesthesia. We herein describe the anatomy, pharmacology, technique and results of local obturator nerve blockade.