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.     

Transfer of brachioradialis motor branch to the anterior interosseous nerve in C8‐T1 brachial plexus palsy. An anatomic study

We present an anatomical and histomorphometric study of the transfer of the motor branch to the brachioradialis muscle to the anterior interosseous nerve in recent brachial plexus lesions, involving C8 and T1 roots. The aim of this study was to demonstrate the anatomic constancy of the nerves involved in the transfer, feasibility, and reproducibility of the transfer. We performed a study of 14 elbows in fresh cadavers. Transfer of the motor branch of the brachioradialis muscle to the anterior interosseous nerve was possible in all specimens; there was constancy in the origin and entry into the muscle of the donor nerve, and it was always possible to dissect the recipient nerve at the level of the donor nerve, thereby allowing for direct coaptation of the nerves. The mean diameter of the anterior interosseous nerve was 2.9 ± 0.5 mm and the mean diameter of the brachioradialis muscle branch was 2 ± 0.4 mm. The branch to the brachioradialis muscle contains an average of 550 ± 64 myelinated axons and the anterior interosseous nerve has an average of 2266 ± 274 myelinated axons. The anatomic study in cadavers showed that the technique is justified and anatomically reproducible. © 2012 Wiley Periodicals, Inc. Microsurgery, 2013.     

Repair of the femoral nerve by two motor branches of the obturator nerve: A case report

Complete femoral nerve palsies are uncommon but devastating injuries when they are caused by large nerve defects. Direct repair is usually not possible and nerve grafting renders uncertain outcomes. Recent studies proposed different peripheral nerve transfers as treatment strategies for large femoral nerve defects. We report a clinical application of a nerve transfer to reinnervate the quadriceps muscle with two motor branches of the obturator nerve in a 48 years-old man that was diagnosed with a femoral nerve palsy after resection of a retroperitoneal schwannoma. The branches supplying the gracilis and adductor longus muscles were transferred to the motor branch of the femoral nerve to the quadriceps muscle at 6 months postinjury. At 34 months of follow-up, knee extension was quoted M4. The presented nerve transfer may be feasible, technically simple, and renders good functional outcomes.     

Transfer of two motor branches of the anterior obturator nerve to the motor portion of the femoral nerve: an anatomical feasibility study

Femoral nerve lesions are uncommon, but very distressing at the functional level because of the absence of knee locking mechanism by the quadriceps muscle. We propose here a new neurotization procedure of obturator nerve motor branches to the motor portion of the femoral nerve in the thigh. This study was conducted on five cadavers. The motor portion of the femoral nerve and the motor branches of the obturator nerve, supplying the gracilis and adductor longus muscles, were isolated. The distance between nerve endings and diameter were measured to determine if a direct neurorrhaphy was possible between the femoral nerve and the two united branches of the obturator nerve. The overlap between the two nerve endings was 26 mm on average, and the mean diameter of the two nerve endings was 3.6 mm for the united branches of the obturator nerve and 3.7 mm for the femoral nerve. Thus, a direct suture was possible in all cases. In this anatomical study, access to the femoral nerve and two united branches of the obturator nerve was easy, in contrast to transfer in the pelvis. Moreover, direct suture without tension was possible in all cases. Thus, this transfer is simple and perfectly reproducible and may have a clinical application in proximal femoral nerve injuries.     

Insufficiency of the hip adductor after anterior obturator neurectomy in 42 children with cerebral palsy

Forty-two children with cerebral palsy treated between 1970 and 1982 for correction of adduction and internal rotation of the hip were studied. According to the combined procedures and the effects of surgical manipulations, two groups were evaluated. The results of release of the adductor longus and gracilis without anterior obturator neurectomy were satisfactory when combined with proximal release of medial hamstrings. Hypertonicity in hip adduction was relieved. In cases of loss of function of the adductor brevis with anterior obturator neurectomy, the results were not satisfactory, and hyperabduction of the hip was inadequate. The adductor brevis plays an important role in stability of the hip.     

胸腔镜下切取膈神经移位重建全臂丛根性撕脱伤手部功能初步报告

目的探讨胸腔镜下膈神经超长切取、移位重建全臂丛根性撕脱伤手部功能的可行性。方法全臂丛根性撕脱伤3例,胸腔镜下于邻膈肌处切断膈神经,逆行游离胸腔内全长膈神经及其血管组织蒂,并由第二肋间引出,经胸大肌下移位至上臂上内侧,分别与尺神经前内侧部吻合2例,与移植股薄肌之闭孔神经前支吻合1例。结果2例膈神经联合第3～6肋间神经运动支移位修复尺神经者,结合短期免疫抑制剂FK506口服治疗,术后12个月手内肌肌电图检测均出现再生电位,1例随访15个月出现手内肌收缩。1例用以重建屈肘、屈指屈拇的移植股薄肌术后7月出现肌肉收缩,随访12个月肌力达M3。结论胸腔镜下全长切取膈神经,作为运动性动力神经移位应用于全臂丛根性撕脱伤的治疗,可在短时间内有效重建屈指屈拇功能,并有使手内肌神经再支配、开始恢复手内肌收缩功能的迹象。     

Ultrasound guided obturator nerve block: a single interfascial injection technique

We describe a new technique of single interfascial injection for 25 patients scheduled for transurethral bladder tumor resection. An ultrasound probe was placed at the midline of inguinal crease and moved medially and caudally to visualize the fascial space between the adductor longus (or pectineus) and adductor brevis muscles. We injected 20 mL 1% lidocaine containing epinephrine into the interfascial space using a transverse plane approach to make an interfascial injection, not an intramuscular swelling pattern. And just distally, firm pressure was applied for 3 min. Afterwards, surgery was performed under spinal anesthesia. The time required for identification and location of the nerve was 20 ± 15 and 30 ± 15 s, respectively. Adductor muscle strength, which was measured with a sphygmomanometer, decreased in all patients, from 122 ± 26 mmHg before blockade to 63 ± 11 mmHg 5 min after blockade. No movement or palpable muscle twitching occurred in 23 cases, slight movement of the thigh not interfering with the surgical procedure was observed in 1 case, thus the obturator reflex was successfully inhibited in 96% of cases. Ultrasound-guided single interfascial injection is an easy and successful technique for obturator nerve block.     

Axon counts of potential nerve transfer donors for peroneal nerve reconstruction

BACKGROUND:

The common peroneal nerve is the most commonly injured nerve in the lower limb. Nerve transfer using expendable donor nerves is emerging in the literature as an alternative surgical procedure to traditional treatments.

OBJECTIVE:

To identify potential donors of motor axons from the tibial nerve that can be transferred to the common peroneal nerve branches.

METHODS:

Using 10 human cadaveric lower extremities, all motor nerve branches of the tibial nerve were identified and biopsied. These were compared with the motor branches to tibialis anterior and extensor hallucis longus (branches of the deep peroneal nerve).

RESULTS:

The most suitable donor nerves with respect to cross-sectional area to tibialis anterior (cross sectional area [mean ± SD] 0.255±0.111 mm) was the motor branch to lateral gastrocnemius (0.256±0.105 mm). When comparing the total number of axons, the branch to the tibialis anterior had a mean of 3363±1997 axons. The branch to the popliteus was most similar, with 3317±1467 axons. The most suitable donor nerves for the motor branch to extensor hallucis longus (cross sectional area 0.197±0.302 mm) with respect to cross-sectional area was the motor branch to flexor hallucis longus (0.234±0.147 mm). When comparing the total number of axons, the branch to the extensor hallucis longus had an average of 2062±2314 axons. The branch to the lateral gastrocnemius was most similar with 2352±1249 axons and was a suitable donor.

CONCLUSION:

Nerve transfers should be included in the armamentarium for lower extremity reinnervation, as it is in the upper limb.     

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.     

Obturator neuropathy. An anatomic perspective.

Entrapment of the anterior division of the obturator nerve is a recently described cause of medial groin pain. This anatomic study examines the extrapelvic course of the nerve and related fascia in the adductor region to provide an anatomic basis for the syndrome and to aid in surgical treatment. Twelve anatomic specimen limbs were dissected to document the extrapelvic course of the obturator nerve, the myofascial arrangement, and the vasculature. A thirteenth limb was prepared with intraarterial glycerin to examine the vessels in more detail. A distinct fascial plane was found deep to the adductor longus and pectineus overlying the anterior division of the obturator nerve. The arterial supply to the adductor muscles is related intimately to the nerve and its branches, with associated local thickening of the fascial connective tissue. The relationship between the nerve, vessels, and fascia appears sufficient to result in an entrapment syndrome. The anatomic findings from this series will help plan the surgical treatment of this condition.     

Ultrasound-guided obturator nerve block

We reviewed the technique and anatomy for the ultrasound-guided obturator nerve block, especially interadductor approach. Although it is sometimes difficult to observe obturator nerve in the ultrasound image, obturator nerve block is completed observing three muscle layers, adductor longus muscle, adductor blevis muscle and adductor magnus muscle, in the ultrasound image. Local anesthetics are injected between the muscle layers confirming the needle tip and spread of the solution. This technique will reduce incomplete effect or side effects of the obturator nerve block.     

脑瘫SPR术后遗留髋内收畸形的个体化手术治疗

目的评价痉挛型脑瘫患者腰骶段选择性脊神经后根切断术（SPR）后遗留髋内收畸形的手术方案选择及临床疗效。方法回顾性分析2008年8月至2012年8月北京中医药大学东直门医院收治的126例脑瘫SPR术后遗留髋内收畸形患者的临床资料,根据肌肉挛缩的范围和畸形程度采取不同的手术方式,包括长收肌、短收肌、股薄肌、髂腰肌、闭孔神经前支切断术等。观察患者术后髋外展角度及畸形矫正情况。结果 126例患者随访14~38个月（平均22个月）。术后髋内收畸形均较术前有明显改善,其中术后髋外展角度≥30°118例、20°~30°8例,缓解率100%（126/126）,满意率93.6%（118/126）。未出现下肢感觉障碍、髋外展或外旋畸形。结论对于脑瘫SPR术后遗留的髋内收畸形,根据个体情况不同,采用肌肉切断松解、闭孔神经前支切断术等个体化治疗方案,可取到满意的临床疗效。     

A modified free gracilis flap in the rat

We present in this paper the use of a combined neurovas-cularized flap of gracilis muscle and inguinal skin in the rat with the femoral vessels and obturator nerve serving as the pedicles. The epigastric, saphenous, and muscular branch vessels arising from the femoral vessels were preserved, and a portion of adductor magnus muscle was included in the flap to protect the delicate muscle vessels at their origins. The inguinal skin and muscle flap both had independent blood supplies, thus, separate assessment of muscle and skin rejection was possible in the single transplanted “packet.” The muscle flap with the reconnected motor nerve regained contractile ability upon nerve stimulation within 30 days after the iso-transplantation. The results suggest that the modified gracilis myocutaneous flap provides an ideal model for transplantation research. © 1994 Wiley-Liss, Inc.     

Technique of harvesting the gracilis for free functioning muscle transplantation

In this article, we describe our technique and experience in harvesting the gracilis muscle for free functioning muscle transplantation (FFMT). The gracilis is the most commonly used muscle for FFMT. The main indication for gracilis FFMT is traumatic brachial plexus injury. Gracilis muscle has a class 2 vascular pedicle, with a dominant vascular pedicle originating from the profunda femoris vessels and a single motor nerve originating from the obturator nerve. During gracilis harvest, it is important to include the entire fascia around the muscle to ensure vascularity of the skin paddle and enhance muscle gliding in its new bed. Mobilization of the adductor longus allows tracing of the pedicle to its origin from the profunda femoris vessels, hence, achieving the maximum available length of the pedicle. Lengthening of gracilis tendon with a periosteal strip provides a free gracilis long enough to span the distance from the clavicle to the distal forearm. The main complications are related to the wound, and these include delayed healing, infection, and scar-related problems. The functional deficit after gracilis harvest is negligible.     

臂丛神经根性撕脱伤修复前臂屈肌功能的应用解剖

目的为健侧C7移位重建前臂屈肌功能提供解剖学依据。方法在30侧甲醛固定的成人尸体标本上,观测椎前通路健侧C7移位修复患侧下干或内侧束时,相关前臂屈肌神经入肌点和尺神经深支起点至健侧C7神经吻合口之间的距离;观测上述肌肉的神经来源;测量C7及其前、后股的长度。结果 C7及其前、后股长度分别为(58.8±4.2)、(15.4±6.7)、(8.8±4.4)mm。C7神经吻合口至入肌点长度:至掌长肌支为(369.4±47.3)mm,至指浅屈肌支为(390.5±38.8)mm(正中神经发出)和(413.6±47.4)mm(骨间前神经发出),至示中指指深屈肌支为(346.2±22.3)mm(正中神经发出)和(408.2±23.9)mm(骨间前神经发出),至环小指指深屈肌支为(344.2±27.2)mm,至拇长屈肌支为(392.5±29.2)mm(正中神经发出)和(420.5±37.1)mm(骨间前神经发出),至旋前方肌支为(495.8±31.3)mm,至尺神经深支起点为(548.7±30.0)mm。骨间前神经均发支支配拇长屈肌、示中指指深屈肌和旋前方肌,支配指浅屈肌5侧(16.7%);正中神经主干均发支支配掌长肌和指浅屈肌,支配示中指指深屈肌10侧(33.3%)、拇长屈肌6侧(20.0%)。结论如果采取腓肠神经移植,前臂肌肉功能在1年内均不能恢复;肱骨短缩、1个神经吻合口有利于前臂屈肌功能的恢复。     

Anatomy of the obturator region: relations to a trans-obturator sling

Our objective was to determine the relationships between a trans-obturator sling and anatomic structures within the obturator region. The obturator regions of six cadavers were dissected and distances from the mid-point of the ischiopubic ramus to the muscles, nerves, and vessels of the region were measured. A trans-obturator sling was placed and distances from the device to the same anatomic structures were determined. Four additional cadavers were dissected to determine the device route of passage. The obturator canal is on average 4.4 cm from the midpoint of the ischiopubic rami. The trans-obturator sling passes on average 2.4 cm inferior-medial to the obturator canal. The anterior and posterior divisions of the obturator nerve are on average 3.4 and 2.8 cm, respectively, from a passed trans-obturator device. The device passed on average 1.1 cm from the most medial branch of the obturator vessels. Vascular and nerve structures are within 1–3 cm of the path of any device passed through the obturator foramen. A trans-obturator sling risks injury to these structures, although the small caliber of the vessels and the confined space in which they would bleed make the consequences of injury uncertain.Editorial Comment: The authors performed anatomic dissections in fresh frozen cadavers to better understand the anatomy faced during the performance of a transobturator sling procedure. Since this anatomy has not been critically analyzed by the vast majority of pelvic surgeons, it is important for the practicing pelvic surgeon to attain a very clear image of the vascular and neurologic relationships in this area. The dissections were performed with the patients in high lithotomy position. Therefore, there is great clinical value to these dissections. However, the surgeon must also realize that a significant degree of variability exists, especially as related to vascular anatomy. This has implications for the safe performance of this novel approach to stress incontinence     

Pelvic floor anatomy in classic bladder exstrophy using 3-dimensional computerized tomography: initial insights

PURPOSE: We present the pelvic floor anatomy of the major pelvic floor musculature in classic bladder exstrophy, including the levator ani, obturator internus and obturator externus. By improving our knowledge of pelvic floor anatomy we hope to understand better the relationship of the pelvic floor to the bony anatomy as well as the role of osteotomy in changing pelvic floor anatomy to enhance urinary control after surgery. MATERIALS AND METHODS: 3-Dimensional computerized tomography was done in 6 boys and 1 girl, including 5 patients 2 days to 5 months old (mean age 7 months) undergoing primary closure and 2 who were 4 and 8 years old undergoing repeat closure. The pelvic floor musculature, including the levator ani, obturator internus and obturator externus, in these cases was compared to that in 26 age and sex matched controls. RESULTS: The levator ani musculature encompasses a significantly wider area of 9.5 cm.2 in patients with classic bladder exstrophy than in controls. The anterior segment of the levator ani was shorter (1.2 cm.) and the posterior segment of the levator ani was longer (2.5 cm.) than in controls. The degree of divergence of the levator ani in classic exstrophy was significantly more outwardly rotated (38.8 degrees) than controls. In addition, the transverse diameter of the levator hiatus was 2-fold that in our control group and in that of published controls, while the length of the hiatus was 1.3-fold that in normal controls. There was also significant flattening, involving a 31.7 degree decrease in steepness between the right and left halves of the levator ani, of the puborectal sling in classic bladder exstrophy versus controls. Because of these findings, there is more anterior superior rotation in the pelvic floor in exstrophy cases. The obturator internus was more outwardly rotated (15.1 degrees) in exstrophy and the obturator externus also showed more outward rotation (16.9 degrees) than in controls. CONCLUSIONS: This study provides better understanding of the pelvic floor anatomy in classic bladder exstrophy. Significant differences have been documented in the pelvic floor in classic bladder exstrophy cases and controls. Hopefully these differences may have a pivotal role in providing new insight into long-term issues, such as urinary and fecal incontinence, and pelvic organ prolapse, in classic bladder exstrophy.     

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     

Anatomic variance in common vascular pedicle of the gracilis and adductor longus muscles: feasibility of double functioning free muscle transplantation with single pedicle anastomosis

Fifty thighs from fresh human cadavers were studied to evaluate the feasibility of a double functioning free muscle transfer of the gracilis and adductor longus with single common vascular pedicle anastomosis. Methylene blue intra-arterial injection and loupe-magnified dissection were used to demonstrate three groups of vascular patterns in these two muscles. The common vascular pedicles of 88% of our specimen muscles were long enough for possible anastomosis. Ten percent (type B2) were quite short, making microsurgical procedure difficult. Two percent (type A3) of our specimens were not suitable for single anastomosis. Four percent of our gracilis muscles had two major arterial pedicles that branched from the common pedicle in a Y-shaped configuration. If only one pedicle of this type is harvested during a free gracilis muscle transfer, it may cause inadequate flap perfusion. Four specimens were studied using contrast media angiography to confirm both are Mathes and Nahai type II muscle flaps. In summary, this study typed the common vascular pedicle of our sample of gracilis and adductor longus muscles and confirmed the feasibility of double functioning free muscle transfer of the gracilis and adductor longus with single vascular anastomosis.     

Quantitation of and superficial surgical landmarks for the anterior interosseous nerve

OBJECT: There are scant data regarding the anterior interosseous nerve (AIN) in the neurosurgical literature. In the current study the authors attempt to provide easily identifiable superficial osseous landmarks for the identification of the AIN. METHODS: The AIN in 20 upper extremities obtained in adult cadaveric specimens was dissected and quantified. Measurements were obtained between the nerve and surrounding superficial osseous landmarks. The AIN originated from the median nerve at mean distances of 5.4 cm distal to the medial epicondyle of the humerus and 21 cm proximal to the ulnar styloid process. The distance from the origin of the AIN to its branch leading to the flexor pollicis longus muscle and to the point it travels deep to the pronator quadratus (PQ) muscle measured a mean 4 and 14.4 cm, respectively. The mean distance from the AIN branch leading to the flexor pollicis longus muscle to the proximal PQ muscle was 12.1 cm, and the mean distance between this branch and the ulnar styloid process was 7.2 cm. The mean diameter of the AIN was 1.6 mm at the midforearm. CONCLUSIONS: Additional landmarks for identification of the AIN can aid the neurosurgeon in more precisely isolating this nerve and avoiding complications. Furthermore, after quantitation of this nerve, the AIN branches can be easily used for neurotization of the median and ulnar nerves, and with the aid of a transinterosseous membrane tunneling technique, passed to the posterior interosseous nerve.