A new ultrasound‐guided pubic approach for proximal obturator nerve block: clinical study and cadaver evaluation

We evaluated an alternative technique for ultrasound‐guided proximal level obturator nerve block that might facilitate needle visualisation using in‐plane ultrasound guidance. Twenty patients undergoing transurethral bladder tumour resection requiring an obturator nerve block were enrolled into a prospective observational study. With the patient in the lithotomy position, the transducer was placed on the medial thigh along the extended line of the inguinal crease, and aimed cephalad to view a thick fascia between the pectineus and obturator externus muscles that contains the obturator nerve. A stimulating nerve block needle was inserted at the pubic region and advanced in‐plane with the transducer in an anterior‐to‐posterior direction. Eight ml levobupivacaine 0.75% was injected within the fascia. The median (IQR [range]) duration for ultrasound identification of the target and injection were 8.5 (7–12 [5–24]) s and 62 (44.5–78.25 [39–383]) s, respectively. All blocks were successful. A cadaver evaluation demonstrated that the dye injected into the target fascia using our technique travelled retrogradely through the obturator canal, and surrounded the anterior and posterior branches of the obturator nerve both proximally and distally to the obturator canal. We believe that this is a promising new technique for ultrasound‐guided proximal level obturator nerve block.     

Pubic tubercle side approach to the obturator nerve block

BACKGROUND: The authors describe the pubic tubercle side approach of the obturator nerve block for the management of adductor muscle constriction associated with the transurethral resection of the lateral wall bladder tumor. METHODS: The pubic tubercle side approach of the obturator nerve block was performed by a inserting needle at the midpoint of the femoral artery and the pubic tubercle. After the needle encountered the superior ramus of pubis, the needle was redirected vertical or slightly caudal, passeing the vicinity of the inferior margin of the superior ramus of pubis, and then advanced to the trunk of the obturator nerve. The obturator nerve was identified by its response to nerve stimulation. The pubic tubercle side approach using more than 5 ml of 1.0% lidocaine was performed by a single injection until there was no response to nerve stimulation. On the other hand, by the traditional approach to the obturator nerve block, after the initial local anesthetic injection the needle was redirected lateral and slightly caudal. If the response to nerve stimulation was still elicited, more local anesthetic was administered. RESULTS: Evaluation of the efficacy of the pubic tubercle side approach was performed in-terms of quantity of the local anesthetic used and the success rate. In comparison with the traditional approach, a smaller dose of local anesthetic was used in spite of the higher success rate. CONCLUSIONS: The pubic tubercle side approach of the obturator nerve was useful and without complications in comparison with the traditional approach.     

Interadductor approach to obturator nerve block for transurethral resection procedure: comparison with traditional approach

Purpose. We compared the interadductor approach of obturator nerve block with the traditional approach in terms of the insertion-adductor contraction interval (ICI), success rate, completion of the block, and plasma lidocaine concentration. Methods. An obturator nerve block by the interadductor approach was performed by needle insertion 1 cm behind the adductor longus tendon and 2 cm lateral to the pubic arch in 12 patients, and by the traditional approach in 12 patients. Results. The ICI with the interadductor approach was significantly shorter than that with the traditional approach. The success rate, completion of the block, and plasma lidocaine concentrations were similar with both approaches. Conclusion. The interadductor approach can provide faster identification of the obturator nerve than the traditional approach. Received: January 29, 2001 / Accepted: December 12, 2001     

超声引导下腹股沟径路闭孔神经阻滞的应用

目的观察超声引导下腹股沟径路闭孔神经阻滞在经尿道膀胱肿瘤电切术中预防闭孔神经反射的临床效果和并发症。方法行经尿道膀胱肿瘤电切术患者50例,随机分为2组：超声引导腹股沟径路闭孔神经阻滞组（UONB组,25例）和传统闭孔神经阻滞组（TONB组,25例）。闭孔神经阻滞前后分别测定阻滞侧大腿内收肌力量。记录两种闭孔神经阻滞方法成功率及副作用发生情况等。结果 UONB组和TONB组患者阻滞侧大腿内收肌力量闭孔神经阻滞后分别为52±7mmHg和66±19mmHg,UONB组显著小于TONB组（P=0.001）。UONB组阻滞成功率为97.4%,显著高于TONB组（74.2%）（P=0.01）。结论超声引导闭孔神经阻滞成功率高,可以安全、有效的预防膀胱肿瘤电切术闭孔神经反射。     

Sonographic imaging of the obturator nerve for regional block

BACKGROUND AND OBJECTIVES: Today, there is a growing appreciation of the importance of the obturator nerve in clinical anesthesia. The aim of this study is to describe the ultrasound appearance of the obturator nerve for potential utility in guiding these nerve blocks. METHODS: We scanned left and right inguinal regions of 20 volunteers lateral and distal to the pubic tubercle (PT) and assessed visibility, size and shape, and depth from the skin of common obturator nerves and their associated divisions. In addition to the volunteer study, we retrospectively reviewed a clinical series of obturator nerve blocks performed with ultrasound guidance and nerve stimulation. RESULTS: The obturator nerve can be sonographically visualized by scanning along the known course of the nerve; the anterior division characteristically converges toward the posterior division along the lateral border of the adductor brevis muscle to form the common obturator nerve more proximally. In the set of 20 volunteers, 25% (10/40) of common, 85% (34/40) of anterior, and 87.5% (35/40) of posterior obturator nerves were sonographically identified. The common obturator nerve was visualized 1.3 +/- 1.5 cm distal and 2.3 +/- 1.2 cm lateral to the PT. Divisions were visualized 2.1 +/- 2.0 cm distal and 2.1 +/- 1.2 cm lateral to the PT. The nerves (common, anterior, and posterior) averaged 2.7 +/- 1.2 mm, 1.4 +/- 0.6 mm, and 1.7 +/- 0.6 mm in anterior-posterior dimension and 9.0 +/- 4.3 mm, 9.6 +/- 3.9 mm, and 10.9 +/- 4.1 mm in medial-lateral dimension and were 25.9 +/- 7.6 mm, 15.5 +/- 3.9 mm, and 29.3 +/- 7.9 mm below the skin surface. The common obturator nerve and its anterior and posterior divisions are all relatively flat nerves with average anterior-posterior/medial-lateral dimension ratios of 0.32, 0.18, and 0.18, respectively. In the clinical series, nerve identification was confirmed with nerve stimulation (n = 6 block procedures, mean threshold stimulating current for evoked adductor contraction = 0.70 +/- 0.14 mA). CONCLUSIONS: The obturator nerve and its divisions are the flattest peripheral nerves yet described with ultrasound imaging. Knowledge of the obturator nerve's ultrasound appearance facilitates localization of this nerve for regional block and may increase success of such procedures.     

A new anterior approach to the sciatic nerve block

BACKGROUND: Although several anterior approaches to sciatic nerve block have been described, they are used infrequently. The authors describe a new anterior approach that allows access to the sciatic nerve with the patient in the supine position. METHOD: Sciatic nerve blocks were performed in 22 patients. A line was drawn between the inferior border of the anterosuperior iliac spine and the superior angle of the pubic symphysis tubercle. Next, a perpendicular line bisecting the initial line was drawn and extended 8 cm caudad. The needle was inserted perpendicularly to the skin, and the sciatic nerve was identified at a depth of 10.5 cm (9.5-13.5 cm; median and range) using a nerve stimulator and a 15-cm b-beveled insulated needle. After appropriate localization, either 30 ml mepivacaine, 1.5% (group 1 = knee arthroscopy; n = 16), or 15 ml mepivacaine, 1.5%, plus 15 ml ropivacaine, 0.75%, (group 2 = other procedures; n = 6) was injected. RESULTS: Appropriate landmarks were determined within 1.3 min (0.5-2.0 min). The sciatic nerve was identified in all patients within 2.5 min (1.2-5 min), starting from the beginning of the appropriate landmark determination to the stimulation of its common peroneal nerve component in 13 cases and its tibial nerve component in 9 cases. A complete sensory block in the distribution of both the common peroneal nerve component and the tibial nerve component was obtained within 15 min (5-30 min). A shorter onset was observed in patients who received mepivacaine alone compared with those who received a mixture of mepivacaine plus ropivacaine (10 min [5-25 min] vs. 20 min [10-30 min]; P < 0.05). Recovery time was 4.6 h (2.5-5.5 h) after mepivacaine administration. The addition of ropivacaine produced a block of a much longer duration 13.8 h (5.2-23.6 h); P < 0.05. No complications were observed. CONCLUSIONS: This approach represents an easy and reliable anterior technique for performing sciatic nerve blocks.     

Ultrasound-guided retrolaminar block versus ilioinguinal nerve block for postoperative analgesia in children undergoing inguinal herniotomy: A randomized controlled trial

Study objectiveUltrasound-guided retrolaminar block (RLB) is a new, safe and technically easy nerve block. To our knowledge, no studies have evaluated its analgesic efficacy in pediatric patients. This study aimed to compare the postoperative analgesic efficacy of RLB and ilioinguinal nerve block (INB) in pediatric patients undergoing unilateral inguinal herniotomy.DesignSuperiority, prospective, randomized, double-blinded, controlled study.SettingOperating rooms and wards of Mansoura University Children's Hospital, Egypt.PatientsSixty-five patients aged 2 to 6 years undergoing unilateral inguinal herniotomy were enrolled.InterventionsIn the ultrasound-guided RLB group (n = 30), we injected 0.5 mL/kg bupivacaine 0.25% into the retrolaminar space between the lamina of T12 and the paraspinal muscles and in ultrasound-guided INB group (n = 30), 0.5 mL/kg bupivacaine 0.25% was injected for INB.MeasurementsThe primary outcome measure was the number of patients requiring ibuprofen as rescue analgesia and the secondary outcome measures were intraoperative hemodynamic changes and the postoperative FLACC (Face, Legs, Activity, Cry, Consolability) score.Main resultsThe number of patients who needed rescue analgesia in the first postoperative 24 h was significantly lower (P = 0.023) in the RLB group [5 (16%)] than the INB group [13 (43%)]. The mean (SD) arterial blood pressure and heart rate were significantly higher (P < 0.001) during sac traction in the INB group [74.07 (2.99), 97.33 (6.98)] than the RLB group [67.73 (3.55), 90.79 (5.13)]. The postoperative FLACC scores at 4, 6, 12, and 24 h were significantly lower (P < 0.05) in the RLB group than in the INB group.ConclusionRetrolaminar block is superior to ilioinguinal nerve block in providing postoperative analgesia in pediatric patients undergoing unilateral inguinal herniotomy.     

Adding a selective obturator nerve block to the parasacral sciatic nerve block: an evaluation

Our aim was to objectively evaluate the efficacy of obturator nerve anesthesia after a parasacral block. Patients scheduled for knee surgery had a baseline adductor strength evaluation. After a parasacral block with 30 mL 0.75% ropivacaine, sensory deficit in the sciatic distribution (temperature discrimination) and adductor strength were assessed at 5-min intervals. Patients with an incomplete sensory block (defined as a temperature discrimination score of less than 2 in the 3 cutaneous distributions of the sciatic nerve tested) 30 min after the parasacral block were excluded from the study. Subsequently, a selective obturator block was performed with 7 mL 0.75% ropivacaine and adductor strength was reassessed at 5 min intervals for 15 min. Finally, a femoral block was performed using 10 mL 0.75% ropivacaine. Patient discomfort level during each block was assessed using a visual analog scale (VAS). Thirty-one patients completed the study. Five patients were excluded as a result of inadequate sensory block in the sciatic distribution 30 min after the parasacral block (success rate of 89%). Thirty min after the parasacral block, adductor strength decreased by 11.3% +/- 7% compared with baseline (85 +/- 24 versus 97 +/- 28 mm Hg, P = 0.002). Fifteen min after the obturator nerve block, adductor muscle strength decreased by an additional 69% +/- 7% (16.6 +/- 15 versus 85 +/- 24 mm Hg, P < 0.0001). VAS scores were similar for all blocks (26 +/- 19, 28 +/- 24, and 27 +/- 19 mm for parasacral, obturator, and femoral respectively). Four parasacral blocks were simulated in 2 fresh cadavers using 30 mL of colored latex solution. The spread of the die in relation to the obturator nerve was assessed. Injection of 30 mL colored latex into cadavers resulted in spread of the injectate restricted to the sacral plexus. These findings demonstrate the unreliability of parasacral block to achieve anesthesia of the obturator nerve. A selective obturator block should be considered in the clinical setting when this is desirable.     

Distal digital nerve grafts: clinical and anatomical studies.

An anatomical study of the terminal branches of the digital nerves of thumb and finger indicated a constant trifurcation at the level of the distal interphalangeal joint. Twelve microscopic interfascicular nerve grafts were done in 11 patients who had nerve division at this level with insensitive fingertips. All patients exhibited improved sensibility. Eight of 12 or 67% achieved 6 mm of two-point discrimination. Although there were no children in this study, the subjects under 30 years of age enjoyed better final results.     

A report on 107 cases of obturator nerve block

The obturator nerve passes in close proximity to the inferolateral bladder wall. Transurethral resection of bladder tumors close to these areas may stimulate the obturator nerve, causing violent adductor contraction and possible inadvertent bladder perforation. To avoid this reaction, local anesthetic blockade of the obturator nerve as it passes through the obturator canal is effective to stop adductor spasm during spinal anesthesia. We performed obturator nerve block in 107 cases by use of insulated needle and nerve stimulator, and measured the depth of the obturator nerve and that of the pubic tubercle. Obesity index was positively correlated with the depth of the obturator nerve as well as the pubic tubercle. However, no correlation was found between the obesity index and the difference of the depth of the obturator nerve and the depth of the pubic tubercle. It is suggested that if the needle is advanced in the direction of the obturator canal about 40mm further after reaching the pubic tubercle, the needle reaches the obturator nerve.     

局部神经阻滞麻醉对腹股沟无张力疝修补镇痛效果及应激反应影响的前瞻性随机对照研究

目的对比局部神经阻滞麻醉与硬膜外麻醉在无张力疝修补手术中镇痛效果及应激反应的影响。方法选取文昌市人民医院2018年6月至2019年6月诊治120例腹股沟疝患者资料。按随机数表法将所有患者分为对照组和研究组,各60例。给予对照组患者硬膜外阻滞麻醉,给予研究组患者局部神经阻滞麻醉。记录2组患者的卧床时间、住院时间、术后疼痛评分、应激反应指标、并发症等情况。结果研究组卧床时间、住院时间较对照组明显缩短,差异有统计学意义(P<0.05);2组患者的术后疼痛评分差异无统计学意义(P>0.05);研究组白介素-6、肿瘤坏死因子-α与C反应蛋白等应激指标较对照组明显降低,差异无统计学意义(P<0.05);研究组围手术期尿潴留、呕吐恶心发生率与对照组相比明显降低,差异有统计学意义(P<0.05);2组患者的复发率、感染率、慢性疼痛发生率,差异无统计学意义(P>0.05)。结论腹股沟无张力疝修补手术局部神经阻滞麻醉与硬膜外麻醉效果相当,但能缩短住院时间和术后卧床时间,对机体应激反应的影响较小,围手术期并发症发生率低。     

Infraorbital nerve block in neonates for cleft lip repair: anatomical study and clinical application

Infraorbital nerve block in neonates is not well described althoughit has been suggested that bilateral infraorbital nerve blockis the local analgesic technique of choice for early repairof cleft lip. The purpose of this study was to determine thelocation of the infraorbital nerve in neonatal cadavers andto identify clinically useful landmarks. Thirty infraorbitalnerves were identified in 15 neonatal cadavers with a mean weightof 2.85 (SD 0.32) kg (range 2.45–3.5 kg) via an upperbuccal sulcus incision. The mean distance from the infraorbitalnerve to the base of the alae nasi was 7.7 (SD 1.3) mm on theleft and 7.5 (0.8) mm on the right. A line drawn from the angleof the mouth to the midpoint of the palpebral fissure measured30.6 (1.9) mm (left) and 30.7 (1.8) mm (right). The nerve wassituated approximately halfway along this line at a point 15.5(1.5) mm (left) and 15.2 (1.4) mm (right) from the angle ofthe mouth. These measurements were used to perform bilateralinfraorbital nerve blocks in four neonates undergoing cleftlip surgery under general anaesthesia, thereby providing analgesiawith minimal risk of respiratory depression. (Br. J. Anaesth.1995; 74: 506–508)     

A paravenous approach for the saphenous nerve block

BACKGROUND AND OBJECTIVES: This study assesses a paravenous approach for saphenous nerve block at approximately the level of the tibial tuberosity, and compares it with the conventional technique of blind subcutaneous infiltration between the tibial tuberosity and the gastrocnemius muscle. METHODS: In dissections of 5 cadavers, the saphenous nerve was found very close to the saphenous vein bilaterally. Subsequently, in 20 volunteers, a bilateral saphenous nerve block was performed with 5 mL mepivacaine on each side. Randomly assigned, the block was performed by blind subcutaneous injection using a 23-gauge needle of 2.5 cm on one side and by a paravenous subcutaneous approach on the other. RESULTS: The paravenous approach produced a saphenous nerve block in all 20 volunteers whereas the blind subcutaneous approach was successful in only 6 (33%) (P <.05). Seven volunteers had a painless minor hematoma at the paravenous site and 2 had a hematoma at the classical site. CONCLUSION: The saphenous nerve can be blocked effectively by a paravenous approach using only 5 mL of local anesthetic solution. This approach is advantageous because of its easily identifiable landmark.     

A new approach to sciatic nerve block in the gluteal region

Two personal techniques of sciatic nerve block in the gluteal region were compared in a retrospective study. The study was carried out on 224 patients undergoing elective orthopaedic lower-limb surgery. The block was performed in 107 subjects with a modified Labat's technique, prolonging his line downwards to meet the surface projection of the sciatic nerve, according to Ellis and McLarry. In 117 patients the needle was inserted at the intersection of the hiatus-trochanteric line with a straight line joining the midpoint of the thigh with the posterior-superior iliac spine. The use of these landmarks improved paraesthesia elicitation and increased absolute success rate (66%). A dramatic drop in intra-operative supplemental analgesic and hypnotic needs was observed in these patients. Failure occurred in about 10% with both techniques, whilst side-effects were of minor importance. These results suggest that the new landmarks provide a more precise anatomo-clinical location of the sciatic nerve.     

A new single-position supine approach to sciatic-femoral nerve block.

To overcome the disadvantages of other methods, the authors have devised a procedure for below-the-knee operations, involving a new technic of sciatic-femoral nerve block. The technic has so far been successful without use of adjuvant agents in 90 percent of over 100 patients so handled.