Cubitus varus associated with dislocation of both the medial portion of the triceps and the ulnar nerve.

Five patients with cubitus varus deformities from malunited childhood fractures had dislocation (snapping) of both the medial portion of the triceps and the ulnar nerve over the medial epicondyle. In addition to snapping, these patients had medial elbow pain or ulnar nerve symptoms. Cubitus varus shifts the line of pull of the triceps more medial, which can cause anteromedial displacement of the medial portion of the triceps during elbow flexion. The ulnar nerve is concomitantly pushed or pulled anteromedially by the triceps, and ulnar neuropathy may result from friction neuritis or from dynamic compression by the triceps against the epicondyle. Recognition of both the dislocating ulnar nerve and the snapping medial triceps is crucial in the successful treatment of this pathologic finding. In symptomatic individuals, we recommend either corrective valgus osteotomy of the distal humerus or partial excision or lateral transposition of the snapping medial triceps, or a combination of both. Alternatively, medial epicondylectomy can also eliminate the snapping. Transposition of the ulnar nerve can be performed for ulnar nerve symptoms and/or ulnar nerve instability. Using this approach, correction of the snapping and/or ulnar nerve symptoms was achieved in all cases.     

肘管综合征的应用解剖学研究

目的 研究肘管综合征中尺神经的卡压因素,为临床手术提供解剖学依据.方法 采用解剖学方法对16具(32侧)成人尸体上肢标本进行解剖,观测造成尺神经卡压的Struthers弓形组织、内侧肌间隔和肘管,测量肘管内尺神经的面积、肘管的面积和肘管的长度,测量弓状韧带的长、宽和厚度.观测尺神经的营养血管及伴行长度,观测尺神经的尺侧腕屈肌肌支.结果 32侧上肢标本中12侧存在腱性Struthers弓形组织,10侧有肌性Struthers弓形组织,存在率为68.8%.尺神经在内上髁上方[(11.02±1.16)cm,小x±s.下同]处穿内侧肌间隔,尺神经肘管内面积与肘管面积之比为1:3.86,肘管长度为(1.96±0.18)cm.尺神经伴行血管有尺侧上副动脉和尺侧返动脉后支,尺神经在内上髁下方1cm左右发出尺侧腕屈肌肌支.结论 尺神经在肘管处最容易受压,手术治疗肘管综合征时向上的切口长度约为11.02cm,同时切除Struthers弓形组织和内侧肌间隔;尺神经前置手术时,注意保留与神经伴行的尺侧返动脉后支.     

Subtotal medial epicondylectomy as a surgical option for treatment of cubital tunnel syndrome

Ulnar nerve compression at the elbow is commonly accepted as the second most frequent compressive peripheral neuropathy. The unique anatomic location of the ulnar nerve directly posterior to the medial epicondyle at the elbow places it at risk for injury. With normal motion of the elbow, the ulnar nerve is subjected to compression, traction, and frictional forces. Compression can occur at any of the 5 sites that begin proximally at the arcade of Struthers and end distally where the nerve exits the flexor carpi ulnaris in the forearm. Initial treatment of compressive neuropathy is nonoperative, usually consisting of rest, modification, and/or restriction of elbow or wrist movement. If symptoms persist, especially when accompanied by muscle weakness, surgery is usually indicated. Surgical options include decompression in situ, medial epicondylectomy, transposition of the ulnar nerve (subcutaneous, intramuscular, or submuscular), and/or a combination of these procedures. Careful decompression with a subtotal medial epicondylectomy is a valuable procedure that allows decompression at all levels with minimal risk of devascularizing the nerve or creating elbow instability.     

The cubital tunnel and ulnar neuropathy

The anatomy of the cubital tunnel and its relationship to ulnar nerve compression is not well documented. In 27 cadaver elbows the proximal edge of the roof of the cubital tunnel was formed by a fibrous band that we call the cubital tunnel retinaculum (CTR). The band is about 4 mm wide, extending from the medial epicondyle to the olecranon, and perpendicular to the flexor carpi ulnaris aponeurosis. Variations in the CTR were classified into four types. In type 0 (n = 1) the CTR was absent. In type Ia (n = 17), the retinaculum was lax in extension and taut in full flexion. In type Ib (n = 6) it was tight in positions short of full flexion (90 degrees to 120 degrees). In type II (n = 3) it was replaced by a muscle, the anconeus epitrochlearis. The CTR appears to be a remnant of the anconeus epitrochlearis muscle and its function is to hold the ulnar nerve in position. Variations in the anatomy of the CTR may explain certain types of ulnar neuropathy. Its absence (type 0 CTR) permits ulnar nerve displacement. Type Ia is normal and does not cause ulnar neuropathy. Type Ib can cause dynamic nerve compression with elbow flexion. Type II may be associated with static compression due to the bulk of the anconeus epitrochlearis muscle.     

Unrecognized dislocation of the medial portion of the triceps: another cause of failed ulnar nerve transposition

OBJECT: Failed surgical treatment for ulnar neuropathy or neuritis due to dislocation of the ulnar nerve presents diagnostic and therapeutic challenges. The authors of this paper will establish unrecognized dislocation (snapping) of the medial portion of the triceps as a preventable cause of failed ulnar nerve transposition. METHODS: Fifteen patients had persistent, painful snapping at the medial elbow after ulnar nerve transposition, which had been performed for documented ulnar nerve dislocation with or without ulnar neuropathy. The snapping was caused by a previously unrecognized dislocation of the medial portion of triceps over the medial epicondyle. Seven of the 15 patients also had persistent ulnar nerve symptoms. The correct diagnosis of snapping triceps was delayed for an average of 22 months after the initial ulnar nerve transposition. An additional surgical procedure was performed in nine of the 15 cases and, in part, consisted of lateral transposition or excision of the offending snapping medial portion of the triceps. Of the four patients in this group who had persistent neurological symptoms, submuscular transposition was performed in the two with more severe symptoms and treatment of the triceps alone was performed in the two with milder neurological symptoms. Excellent results were achieved in all surgically treated patients. Six patients declined additional surgery and experienced persistent snapping and/or ulnar nerve symptoms. CONCLUSIONS: Failure to recognize that dislocation of both the medial portion of the triceps and the ulnar nerve can exist concurrently may result in persistent snapping, elbow pain, and even ulnar nerve symptoms after a technically successful ulnar nerve transposition.     

The assessment of the ulnar nerve at the elbow by ultrasonography in children

We evaluated the morphological changes to the ulnar nerve of both elbows in the cubital tunnel by sonography in a total of 237 children, of whom 117 were aged between six and seven years, 66 between eight and nine years, and 54 between ten and 11 years. We first scanned longitudinally in the extended elbow and then transversely at the medial epicondyle with the elbow extended to 0 degrees . We repeated the scans with the elbow flexed at 45 degrees , 90 degrees , and 120 degrees . There were no significant differences in the area of the ulnar nerve, but the diameter increased as the elbow moved from extension to flexion in all groups. More importantly, the ulnar nerve was subluxated anteriorly on to the medial epicondyle by 1.5% to 1.9% in extended elbows, by 5.9% to 7.9% in those flexed to 45 degrees , by 40.0% to 44% in those flexed to 90 degrees , and by 57.4% to 58.1% in those flexed to 120 degrees , depending on the age group. Sonography clearly and accurately showed the ulnar nerve and was useful for localising the nerve before placing a medial pin. Because the ulnar nerve may translate anteriorly onto the medial epicondyle when the elbow is flexed to 90 degrees or more, it should never be overlooked during percutaneous medial pinning.     

Minimally invasive release of the cubital tunnel

Entrapment of the ulnar nerve that leads to cubital tunnel syndrome is a common and often disabling disease. Current surgical treatment options involve simple decompression, medial epicondylectomy, or a variety of anterior transposition procedures. Such techniques often involve extensive exposure of the ulnar nerve with prolonged periods of immobilization. Because of this, patients may often experience significant postoperative pain, scarring, and joint stiffness. In this paper, we describe a minimally invasive technique for treating cubital tunnel syndrome using endoscopic assistance. This procedure enables complete ulnar nerve decompression through one small incision. Direct visualization of all potential anatomic compression sites for a distance of 20 cm around the medial epicondyle is possible. This endoscopic approach to cubital tunnel release is appealing, especially to those patients with mild to moderate symptoms who may otherwise be reluctant to undergo a more involved conventional surgery. It decreases postoperative pain, reduces scarring, and promotes an earlier return to activity than traditional open techniques allow, due to a decreased immobilization period.     

肘部尺神经卡压的定位诊断和电生理学研究

目的：对肘部尺神经卡压进行精确定位和电生理学研究。方法：对４６例临床诊断为肘部尺神经卡压患者，除进行常规ＥＭＧ、ＮＣＶ、和尺神经混合神经动作电位（ＭＮＡＰ）测定以外，还进行尺神经短段传导时间（ｓｈｏｒｔｓｅｇｍｅｎｔｃｏｎｄｕｃｔｉｏｎｔｉｍｅ，ＳＳＣＴ）测定。结果：４６例经ＳＳＣＴ测定，发现了卡压最常发生的４个部位，即肱骨内上髁后神经沟、肱尺弓、尺侧腕屈肌的出口和内侧肌间隔。结论：和传统的电生理测定方法相比较，ＳＳＣＴ技术可以更精确地对尺神经卡压进行定位诊断     

The failed ulnar nerve transposition. Etiology and treatment

Various procedures have been recommended for the treatment of cubital tunnel syndrome. Simple decompression in situ, medial epicondylectomy, subcutaneous transposition, intramuscular transposition, and submuscular transposition all have their advocates. The results of the surgical treatment for cubital tunnel syndrome are related to the severity of the compressive neuropathy at the time of diagnosis and to the adequate decompression of the nerve at all sites of potential compression at the time of surgical treatment. Fourteen patients who had previously undergone surgical treatment for cubital tunnel syndrome were evaluated because of persistent pain, paresthesia, numbness, and motor weakness. All patients had documented persistent compression of the ulnar nerve on clinical and electromyographic evaluation. The indication for repeat surgical exploration in all patients was unremitting pain despite nonoperative treatment. All patients had been treated by neurolysis and submuscular transposition of the ulnar nerve as described by Learmonth. The causes of continued pain after initial surgery included retention of the medial intermuscular septum, dense perineural fibrosis of the nerve after intramuscular and subcutaneous transposition, adhesions of the nerve to the medial epicondylectomy site, and recurrent subluxation of the nerve over the medial epicondyle after subcutaneous transposition. Revision surgery was found to be highly successful for relief of pain and paresthesias; however, the recovery of motor function and return of sensibility were variable and unpredictable.     

The cubital tunnel: anatomic, histologic, and biomechanical study.

The anatomy of the cubital tunnel was examined in 19 human cadaveric elbows. Pressure measurements within the cubital tunnel were recorded at the medial epicondyle level and 3 cm distal to the epicondyle in various positions of elbow flexion. Histologic examination of the ulnar nerve was carried out at different levels. A common flexor aponeurosis (CFA) was consistently present in all specimens between the flexor carpi ulnaris and the flexor digitorum superficialis. Pressure measurements were greater distally at the CFA level than proximally in the fibrosseous tunnel. The pressure inside the cubital tunnel increased with increasing flexion at the 3 levels examined. Releasing the arcuate ligament decreased the pressure in the fibrosseous tunnel but not distally at the level of the CFA. An oligofascicular pattern of the ulnar nerve was observed at the level of the medial epicondyle and CFA. This finding was in contrast to the polyfascicular pattern present both proximal and distal to these structures. The findings of our study have shown that an intimate anatomic relationship exists between the ulnar nerve and the CFA. This proximity appears to affect the biomechanics of the cubital tunnel and to contribute to nerve compression by the CFA in the distal tunnel. We also found that elbow flexion increases the pressure in the distal tunnel and that releasing the arcuate ligament alone does not decompress the ulnar nerve in the distal tunnel.     

Comparison between partial and minimal medial epicondylectomy combined with decompression for the treatment of cubital tunnel syndrome

We have performed minimal medial epicondylectomy for cubital tunnel syndrome since 1990 to preserve the anterior medial collateral ligament. In this study we compared surgical outcomes between partial medial epicondylectomy (14 patients) and minimal medial epicondylectomy (18 patients) combined with ulnar nerve decompression for the treatment of cubital tunnel syndrome. Mean preoperative Yasutake scores were 57 +/- 17 points (+/-SD) in the partial epicondylectomy group and 60 +/- 15 points in the minimal medial epicondylectomy group. The postoperative scores were 79 +/- 19 points and 87 +/- 10 points, respectively. Both groups had significant improvement in their Yasutake scores following medial epicondylectomy. Similar improvements in motor conduction velocity were observed. There was no significant difference in improvement of either the Yasutake scores or the motor conduction velocity between the 2 groups. Valgus instability of the elbow was significantly greater in the partial epicondylectomy group. We therefore conclude that minimal medial epicondylectomy combined with ulnar nerve decompression is an effective treatment for cubital tunnel syndrome and that a larger excision of the medial epicondyle should be avoided.     

Latrogenic snapping of the medial head of the triceps after ulnar nerve transposition

We postulate an iatrogenic cause for snapping of the medial head of the triceps. A patient whose ulnar nerve and triceps did not dislocate over the medial epicondyle preoperatively had snapping of a portion of the medial triceps after submuscular transposition of the ulnar nerve. We believe that release of the brachial fascia and excision of the medial intermuscular septum removed the restraint to anterior translation of the medial aspect of the triceps, permitting dislocation of a portion of the medial head of the triceps with elbow flexion in this case. Previous reports of snapping of the triceps resulting after ulnar nerve transposition occurred in patients whose ulnar nerve dislocated preoperatively; in these cases, the triceps was thought to have dislocated preoperatively (along with the ulnar nerve) but was not recognized. Careful intraoperative assessment of the triceps after ulnar nerve transposition should prevent medial triceps instability as a postoperative concern.     

Ultrasound-guided surgical treatment for ulnar nerve entrapment: A cadaver study

Several open and endoscopic techniques for the surgical treatment of ulnar nerve entrapment at the elbow (cubital tunnel syndrome) have been described that provide decompression with or without anterior transposition. Based on our experience with US-guided decompression for carpal tunnel syndrome in our department, we developed a similar surgical technique for the decompression of the ulnar nerve at the elbow. Using sixteen cadaver upper limbs, we performed decompression of all the structures possibly responsible for ulnar nerve compression at the elbow. The structures involved were Struthers’ arcade, the cubital tunnel retinaculum, Osborne's fascia and Amadio-Beckenbaugh's arcade. The procedure was followed by anatomical dissection to confirm complete sectioning of the compressive structures, absence of iatrogenic vascular or nervous injuries and absence of nerve dislocation or instability. There were no remaining compressive structures after the release procedure. There was no iatrogenic damage to the nerves and no nerve dislocation was observed during elbow flexion or extension. In 3.4% cases, a thin superficial layer of one or more of the identified structures remained but these did not appear to compress the nerve based on US imaging. Using ultrasonographic visualization of the nerve and compressive structures is easy. Each procedure can be tailored according to the nerve compression sites. Our cadaveric study shows the feasibility of an US-guided percutaneous surgical release for ulnar nerve entrapment.     

Anterior subcutaneous transposition of the ulnar nerve

Anterior, subcutaneous ulnar nerve transposition decompresses the ulnar nerve and, by transposing anterior to the medial epicondyle, eliminates longitudinal traction forces applied to the nerve during elbow flexion. This article reviews the indications and contraindications of the technique and describes the surgical technique in detail.     

Endoscopic decompression of the ulnar nerve at the elbow

PURPOSE: The ideal operative treatment for cubital tunnel syndrome, the second most common form of peripheral compression neuropathy, remains controversial. We therefore reviewed our series of endoscopically assisted ulnar nerve decompression at the elbow to determine the effectiveness of the procedure, which was intended to minimize perioperative morbidity and scar discomfort. METHODS: In 36 patients (ages 22-76 years) with clinical McGowan grade I (4 patients), II (21 patients), and III (11 patients) and electrophysiologic signs of cubital tunnel syndrome (35 primary, 1 recurrent), 20 cm of the ulnar nerve was released through a 3.5-cm-long skin incision above the medial epicondyle. A 4-mm, 30 degrees standard endoscope and custom-made guiding-dissecting tool were utilized during the procedure, and the mean postoperative follow-up examination was 14 months (range 6-19). RESULTS: No macroscopically visible nerves and vessels were injured during the procedure. The only postoperative complication was hematoma in one patient that resolved after conservative management. One case was converted from endoscopic to open because of a ganglion that surrounded the nerve in the forearm. There was no scar discomfort (ie, painful neuroma, impaired sensibility, or burning sensation) or elbow extension deficit after surgery, and surgical wounds all healed within a week. Outcomes were excellent in 21 of 36 cases and good in 12 of 36 cases. All patients improved electrophysiologically after surgery, were satisfied with the procedure, returned to full activities within 3 weeks, and would have the procedure again. CONCLUSIONS: By using a safe and reliable endoscopic technique characterized by a short incision, minimum soft tissue dissection, and early postoperative mobilization, we were able to preserve the benefits of conventional approaches (namely, complete release and good visualization), while avoiding problems such as painful scarring and elbow contracture.     

Recurrent cubital tunnel syndrome. Etiology and treatment.

Controversy surrounds the treatment of recurrent cubital tunnel syndrome after previous surgery. Irrespective of the surgical technique, namely pure decompression in the ulnar groove and the cubital tunnel distal of the medial epicondyle, and the different methods of volar transposition (subcutaneous, intramuscular, and submuscular), the results of surgical therapy of cubital tunnel syndrome are often not favorable, especially in cases of long-standing symptoms and severe deficits. Twenty-two patients who had previously undergone surgical treatment for ulnar nerve entrapment at the elbow were evaluated because of persistent or recurrent pain, paresthesia, numbness, and motor weakness. Ten patients had undergone a nerve transposition, 5 patients underwent a simple decompression of the ulnar nerve, and 7 patients experienced two previous operations with different surgical techniques. Two patients underwent surgery at our hospital, whereas 20 patients underwent their primary surgery at other institutions. Various surgical techniques were used during the subsequent surgery, such as external neurolysis, subcutaneous anterior transposition, and subsequent transfer of the nerve back into the sulcus. The causes of continued or recurrent symptoms after initial surgery included dense perineural fibrosis of the nerve after subcutaneous transposition, adhesions of the nerve to the medial epicondyle and retention of the medial intermuscular septum. The average follow-up after the last procedure was 7 months (2 - 20 months). All 7 patients with subsequent transfer of the ulnar nerve back into the sulcus became pain-free, whereas only 11 of 15 patients who had external neurolysis or subcutaneous transposition became free of pain or experienced reduced pain. The recovery of motor function and return of sensibility were variable and unpredictable. In summary, reoperation after primary surgery of cubital tunnel syndrome gave satisfactory results in 18 of 22 cases. Subsequent transfer of the ulnar nerve back into the sulcus promises to be useful in cases in which subcutaneous transposition had not been successful.     

Tardy ulnar nerve palsy after fracture non-union medial epicondyle of humerus – An unusual case

Tardy ulnar nerve palsy is a chronic clinical condition characterised by delayed onset ulnar neuropathy. Typically tardy ulnar nerve palsy occurs as a consequence of non-union of lateral condyle in child resulting in cubitus valgus deformity which ultimately is the cause of ulnar nerve palsy. However very few literature are available for tardy ulnar nerve palsy as a result of old fracture of medial epicondyle without cubitus varus or valgus deformity. We report a rare case of tardy ulnar nerve in an adult male with fracture non-union of medial epicondyle of humerus.     

肌电图辅助定位小切口尺神经松解术治疗肘管综合征

目的 评价肌电图辅助定位小切口尺神经松解术治疗肘管综合征的疗效及手术适应证.方法 选取无明显手内在肌萎缩及肘关节畸形,具有典型临床症状和体征的肘管综合征患者12例,术前通过神经短节段传导(short-segment nerve conduction test,SSCT)检测的方法,以相邻两次动作电位波幅下降＞50%或潜伏期差＞0.5ms为定位标准,对上述患者进行卡压点定位,采用小切口局部尺神经松解术式,并观察卡压点术中与术前定位比较.结果 术中观测结果证明尺神经损害部位位于肱骨内上髁上方3 cm到肱骨内上髁下方1cm之间,与术前SSCT法检测卡压部位相符.12例术后均主诉手部有明显轻松感;术后3个月感觉异常全部恢复,刺痛觉及爪形指恢复,捏力和抓握力恢复;术后6个月时小指展肌肌力已完全恢复至正常,两点分辨觉平均为5.0 mm,神经传导速度(NCV)均＞45.0 m/s,波幅开始增加,SSCT无阳性发现;术后1年肌肉萎缩基本恢复,屈肘试验、肘部Tinel征、夹纸试验阴性,7例肌电图无阳性发现,1例NCV仍低于正常标准,但无临床症状及体征.术中观察神经卡压位置与术前肌电图定位相符.结论 肌电图辅助定位小切口尺神经松解术治疗肘管综合征是一种有效的方法.

Abstract：

Objective To evaluate the therapeutic effect of in situ ulnar nerve decompression at the cubital tunnel via a small incision assisted with electromyography localization and discuss the surgical indications.Methods Twelve patients who were diagnosed with idiopathic cubital tunnel syndrome (CuTS) without intrinsic muscle atrophy and elbow deformity were involved in the study.Before the operation, short-segment nerve conduction test (SSCT) was carried out.The exact compression site was determined by the ＞ 50%reduction in amplitude or ＞ 0.5 ms lengthening in latency of action potentials recorded upon stimulation of the ulnar nerve around the elbow at 1 cm intervals.An in situ ulnar nerve release at the compression site was performed.Compression of the ulnar nerve was observed and documented to verify the accuracy of pre-operative SSCT localization.Results Intraoperative findings confirmed that lesions were located from 3 cm above to 1 cm below the medial epicondyle, which coincided with the compression sites determined by SSCT.All the patients reported alleviation of hand discomfort postoperatively.Follow-up at 3 months postoperatively showed that paresthesia in the distribution of the ulnar nerve in the hand disappeared.Pinprick sensation recovered.There was no subjective or measurable weakness in pinch or grip strength and no clumsiness or loss of coordination.Claw deformity disappeared.Six months after the surgery, the strength of abductor digiti minimi returned to normal.Two-point discrimination of the little finger was 5.0 mm on average.Nerve conduction velocity returned to ＞ 45.0 m/s.Action potential amplitude increased and SSCT yielded no positive findings.Mild atrophy was reversed one year postoperatively.Elbow flexion test, Tinel' s sign and Froment' s test were all negative.Conclusion In situ ulnar nerve decompression via a small incision assisted with electromyography localization is a suitable procedure for certain CuTS cases.     

Recurrent ulnar-nerve dislocation at the elbow.

Recurring luxation of the ulnar nerve at the elbow is not uncommon (16.2%), occurring about equally in young and old, male and female, athletes and non-athletes but the greater mobility is usually at the dominant arm. The probable cause of such dislocation is congenital laxity of supporting ligaments. Being more vulnerable to injury than normally-positioned nerves, however, complicating neuritis can does occur. Subluxating nerves which stop on the tip of the medial humeral epicondyle upon 90 degrees or more of flexion at the elbow are more subject to direct trauma than completely displaced neural structures which cross the epicondyle upon elbow flexion. The latter may develop friction neuritis which occurs most frequently in industrial workers and occasionally requires surgical transfer. Deep intramuscular implantation, with or without neurolysis, is definetely superior to subcutaneous placement of the affected nerve. In this report are described chemically-induced ulnar neuritis from cortisone injections about the medial humeral epicondyle; pressure ulnar neuritis in patients with enforced bed rest and from improper positioning on operating table with permanent neural deficit and the relationship of such hypermobile ulnar nerves to extension-flexion (whiplash) trauma to the neck. It is emphasized that most of these complications could have been avoided had the patient and his physician known that such anomalies were present. Of particular importance is the avoidance of pressure to the medial aspect of a flexed elbow in surgical patients under general anesthesia. The unrelated co-existence of intermittently-symptomatic hypermobile ulnar nerves and extension-flexion neck trauma may occur. Recognition of isolated unlar neuritis in these patients is definitely important from the diagnostic, treatment and medical-legal aspects of such cervical spine injuries.