Ulnar nerve strains at the elbow: the effect of in situ decompression and medial epicondylectomy

Strains were measured in the ulnar nerve at the elbow in 10 unembalmed, intact cadavers by using a microstrain gauge. In each cadaver, strains in the ulnar nerve behind the medial epicondyle, occurring between 60 degrees and 140 degrees flexion, were calculated for the following 3 conditions: (1) initial strain before in situ decompression, (2) strain after in situ decompression, and (3) strain after in situ decompression plus medial epicondylectomy. The average strain for each group was compared by using the paired Students t-test with multiple comparisons. The average initial percent strain was not significantly reduced by in situ decompression alone (5.3% to 4.3%). However, the average percent strain after medial epicondylectomy and in situ decompression was -0.54%, which was a significant reduction from the initial percent strain and after decompression alone. In situ decompression of the ulnar nerve at the elbow alone does not relieve the tensile strains at the elbow, which may contribute to cubital tunnel syndrome. Medial epicondylectomy after in situ decompression eliminates ulnar nerve strains with elbow flexion.     

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.     

Modified intramuscular transposition of the ulnar nerve

The ulnar nerve passes posterior to the medial epicondyle and experiences longitudinal strain when subjected to elbow flexion. Furthermore, Osborne's ligament and the arcade of fibers between the 2 heads of the flexor carpi ulnaris (Osborne's fascia) compress the nerve during elbow flexion with narrowing of the cubital tunnel passageway. Some patients experience the added element of nerve subluxation over the posterior edge of the epicondyle. When changes to daytime ergonomic behavior and sleep posture prove insufficient to relieve a patient's symptoms, surgical treatment is warranted. A range of procedures exists from simple decompression, to medial epicondylectomy, to anterior transposition. Transposition has been the most widely used method of treatment with the final position of the nerve lying subcutaneous, intramuscular, or submuscular. Each of the transposition methods has proponents with a variety of arguments made in favor of specific aspects of the surgery. This article presents a form of anterior transposition that seeks to draw the best elements from previously reported techniques with the goal of optimizing results.     

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.     

Is routine ulnar nerve transposition necessary in open release of stiff elbows? Our experience and a literature review

Purpose

Prophylactic release of the ulnar nerve to reduce the incidence of postoperative nerve symptoms in stiff elbows has been recommended. However, the necessity for routine anterior transposition remains unclear. In this study, we aim to gain an insight into the value of routine transposition in open release of stiff elbows.

Methods

We retrospectively reviewed 94 patients suffering from elbow stiffness with no pre-operative ulnar nerve symptoms. Simple decompression (with in situ decompression or epicondylectomy) and subcutaneous anterior transposition were chronologically performed in 53 and 37 patients, respectively. Another four patients were treated by a single lateral approach with no intervention of the ulnar nerve. Pre- and postoperative range of motion and incidence of ulnar nerve symptoms were recorded. The function of ulnar nerve was measured by Amadio rating scale.

Results

The incidence of ulnar nerve dysfuction was 18.9 % (ten of 53) and 8.1 % (three of 37) in the simple decompression and transposition groups, respectively. The mean Amadio scores were 7.62 and 8.22, respectively. All these data showed a statistically significant difference (P?Conclusions The transposition group exhibited a superior nervous outcomes compared with the simple decompression group. No comparison was conducted between the transposition and lateral approach groups because of too few patients in the latter. According to related literature and our experience, we conclude that routine transposition is necessary to prevent postoperative nerve symptoms.     

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.     

尺神经肌下前置术治疗肘管综合征

目的 探讨尺神经松解加肌下前置术治疗肘管综合征的有效性。方法 观测２０例成人尸体上肢标本及３２例患者尺神经移置前后的解剖变化,临床应用３２例。结果 尺侧上副动脉可与尺神经一前置;皮下前置伸肘位时尺神经易受牵拉,肌下前置伸、屈肘时均不受牵拉;新肘管可充分容纳尺神经。３２例中获完整随访２６例。随访期１～３年,１６例（６１．５％）恢复正常。结论 尺神经松解加肌下前置术为治疗肘管综合征较佳术式。     

尺神经肌下前置术后解剖学变化及动态分析

目的从解剖学的角度为治疗肘管综合征选择肌下前置术式提供理论依据. 方法分析32例肘管综合征临床资料,男22例,女10例.年龄17～73岁.观察尺侧上副血管的分支分布及其与尺神经的关系,尺神经病变的部位、范围、粗细等;用扩张器测量新肘管容积.将20侧福尔马林固定的成人尸体上肢标本,分别制成尺神经皮下前置及肌下前置模型,动态观测设定范围内尺神经移位前后肘关节不同伸屈状态下的长度变化,进行对比分析. 结果尺侧上副动脉可与尺神经一同前置,新肘管重建后可充分容纳尺神经.皮下前置伸肘位时,尺神经较移位前被拉长7.55%±0.52%,差异有统计学意义(P＜0.05);肌下前置伸肘位时,尺神经长度与术前比较差异无统计学意义(P＞0.05). 结论肘部尺神经肌下前置术较好地解决了尺神经肘部受压迫及屈肘受牵拉的问题,尺神经前置后其血供及组织床良好,新肘管宽松,对尺神经无卡压,术式符合生物力学及神经生理学要求,是治疗肘管综合征可选择的术式.     

Feasibility of a fascial flap to avoid anterior transposition of unstable Ulnar nerve: A cadaver study

BackgroundCompression of the ulnar nerve at the elbow is the second most frequent site of nerve compression in the upper limb. Upon release, anteposition of the nerve may be necessary to avoid dislocation of the latter when unstable. Numerous techniques are described in the literature (subcutaneous transposition, intramuscular transposition, subfascial transposition, medial epicondylectomy …), none of which is without complications. Based on Han's work, the authors propose a technique of covering the ulnar nerve with epicondylar fascial flap, avoiding transposition, but ensuring good stability of the ulnar nerve.MethodsAs part of the SICM (Italian Society of Hand Surgery) cadaver dissection course (ICLO, Verona, Italy) the authors dissected 36 elbows, of which 20 presented subluxation of the ulnar nerve after its decompression. The fascial flap was therefore made on these 20 elbows, coming from 14 different donors (9 men, 5 women) with an average age of 78 years. The diameter of the ulnar nerve was then measured (at the level of the passage in the cubital canal), the diameter of the newly formed canal, the difference between the two previous measurements (residual space in the flexed elbow canal), and it was verified whether the ulnar nerve was unstable once covered by the flap.ResultsThe mean diameter of the ulnar nerve was 5.1 mm (range 4–6), while the mean diameter of the neo-canal was 10.1 mm (range 8–11) in elbow extension and 8.9 mm (range 7–10) in elbow flexion. The remaining space in the flexed elbow canal was 3.8 mm (range 3–5).In none of the 20 cases the ulnar nerve was dislocated after having made the fascial flap.ConlusionsIn light of the results obtained, the authors think that the use of the epicondylar fascial flap may be a solution to keep in mind to avoid dislocation of the ulnar nerve when it becomes unstable following its decompression. This work obviously needs clinical confirmation on living patients.Level of evidenceV.     

Surgical treatment of ulnar neuropathy.

Ulnar neuropathy is a well recognized clinical entity caused by a variety of pathological lesions around the elbow. The characteristic features include paresthesia and numbness in the little finger and medial half of the fourth digit, weakness of the small muscles of the hand innervated by the ulnar nerve, and a positive Tinel's sign. The diagnosis is confirmed by electrophysiological studies. Current methods of treatment are anterior transposition, neurolysis and medial epicondylectomy of the humerus. Forty-four patients with ulnar neuropathy are described in the present report. Most were males with a median age of 45. The left side was involved more frequently. Results of subcutaneous anterior transposition and medial epicondylectomy are presented along with a review of the literature.     

Subcutaneous anterior transposition versus decompression and medial epicondylectomy for the treatment of cubital tunnel syndrome

A review of the literature often fails to uncover the best procedure for the treatment of cubital tunnel syndrome. This article compares 2 frequently used methods (subcutaneous anterior transposition vs decompression and medial epicondylectomy) for their effectiveness in relieving both subjective and objective symptoms of cubital tunnel syndrome. Between August 1991 and October 1993, nineteen patients underwent surgical decompression by a single surgeon for ulnar neuropathy at the elbow. Factors evaluated included upper extremity range of motion, elbow valgus stress, grip strength, pinch, 2-point discrimination, and pre- and postoperative nerve conduction. A standardized questionnaire was administered to assess subjective relief of symptoms.In the transposition group, grip strength averaged 71.2% of normal and pinch strength 86.6% of normal, and 2-point discrimination averaged 8.0 mm. The derived subjective assessment score was 23.2 of a possible 40. The average ulnar motor conduction velocity across the elbow was 50.1 m/sec preoperatively and 56.3 m/sec postoperatively. In the medial epicondylectomy group, grip strength averaged 79.5% of normal and pinch strength 81.7% of normal, and 2-point discrimination averaged 8.0 mm. The average ulnar motor conduction velocity across the elbow was 45.7 m/sec preoperatively and 55.7 m/sec postoperatively. No statistically significant difference existed between the 2 groups for the aforementioned indexes. These results do not indicate a difference between the outcomes of the patients undergoing either of the procedures. Because epicondylectomy is less technically demanding, with less soft tissue dissection of the nerve, it may be preferred over ulnar transposition.     

Ulnar nerve elongation and excursion in the cubital tunnel after decompression and anterior transposition

We studied the elongation and excursion of cadaveric ulnar nerves during elbow flexion in control conditions and after in situ decompression and anterior subcutaneous transposition. We found that the normal nerve had the greatest elongation (23%) and excursion (14 mm) in the epicondylar groove. Decompression did not alter the excursion, but significantly reduced the elongation in the groove (6%) and increased it proximally (19%). After anterior subcutaneous transposition, the nerve segment which was originally in the groove elongated with elbow extension to the same extent as occurred with the normal nerve during flexion.     

Elbow Positioning and Joint Insufflation Substantially Influence Median and Radial Nerve Locations

Background

The median and radial nerves are at risk of iatrogenic injury when performing arthroscopic arthrolysis with anterior capsulectomy. Although prior anatomic studies have identified the position of these nerves, little is known about how elbow positioning and joint insufflation might influence nerve locations.

Questions/purposes

In a cadaver model, we sought to determine whether (1) the locations of the median and radial nerves change with variation of elbow positioning; and whether (2) flexion and joint insufflation increase the distance of the median and radial nerves to osseous landmarks after correcting for differences in size of the cadaveric specimens.

Methods

The median and radial nerves were marked with a radiopaque thread in 11 fresh-frozen elbow specimens. Three-dimensional radiographic scans were performed in extension, in 90° flexion, and after joint insufflations in neutral rotation, pronation, and supination. Trochlear and capitellar widths were analyzed. The distances of the median nerve to the medial and anterior edge of the trochlea and to the coronoid were measured. The distances of the radial nerve to the lateral and anterior edge of the capitulum and to the anterior edge of the radial head were measured. We analyzed the mediolateral nerve locations as a percentage function of the trochlear and capitellar widths to control for differences regarding the size of the specimens.

Results

The mean distance of the radial nerve to the lateral edge of the capitulum as a percentage function of the capitellar width increased from 68% ± 17% in extension to 91% ± 23% in flexion (mean difference = 23%; 95% confidence interval [CI], 5%–41%; p = 0.01). With the numbers available, no such difference was observed regarding the location of the median nerve in relation to the medial border of the trochlea (mean difference = 5%; 95% CI, −13% to 22%; p = 0.309). Flexion and joint insufflation increased the distance of the nerves to osseous landmarks. The mean distance of the median nerve to the coronoid tip was 5.4 ± 1.3 mm in extension, 9.1 ± 2.3 mm in flexion (mean difference = 3.7 mm; 95% CI, 2.04–5.36 mm; p < 0.001), and 12.6 ± 3.6 mm in flexion and insufflation (mean difference = 3.5 mm; 95% CI, 0.81–6.19 mm; p = 0.008). The mean distance of the radial nerve to the anterior edge of the radial head increased from 4.7 ± 1.8 mm in extension to 7.7 ± 2.7 mm in flexion (mean difference = 3.0 mm; 95% CI, 0.96–5.04 mm; p = 0.005) and to 11.9 ± 3.0 mm in flexion with additional joint insufflation (mean difference = 4.2 mm; 95% CI, 1.66–6.74 mm; p = 0.002).

Conclusions

The radial nerve shifts medially during flexion from the lateral to the medial border of the inner third of the capitulum. The median nerve is located at the medial quarter of the joint. The distance of the median and radial nerves to osseous landmarks doubles from extension to 90° flexion and triples after joint insufflation.

Clinical Relevance

Elbow arthroscopy with anterior capsulectomy should be performed cautiously at the medial aspect of the joint to avoid median nerve lesions. Performing arthroscopic anterior capsulectomy in flexion at the lateral aspect of the joint and in slight extension at the medial edge of the capitulum could enhance safety of this procedure.     

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.     

Pediatric open elbow dislocation without fracture: A case report

INTRODUCTION

Elbow dislocations in children are rare injuries. These injuries are often in the form of complex injuries that is accompanied by the median nerve damage and medial epicondyle fracture in the pediatric age group. Open elbow dislocation without fracture in the pediatric age group has been reported very rarely in the literature.

PRESENTATION OF CASE

The purpose of this study is to present an 8-year-old patient who has open elbow dislocation without fracture accompanying with brachial artery injury. In the clinical examination of the patient, there was an open wound in the transverse antecubital region. After repair of brachial artery injury, open reduction was performed under general anesthesia. In the postoperative clinical examination at 6 months, left elbow flexion was 140°, extension was full and there were no deficit in the supination and pronation of the forearm.

DISCUSSION

Elbow dislocation without fracture in pediatric patients is a very rare injury. Usually the trauma mechanism of elbow dislocation is falling on outstretched hand with elbow in approximately 30° of flexion. However our patient had fallen on outstretched hand with elbow in full extension. Although this type of trauma mechanism is typical for supracondylar humerus fractures in pediatric age group, in our patient an open posterior elbow dislocation without fracture had occurred.

CONCLUSION

Pediatric elbow dislocations are rare injuries and the management of these injuries can be technically demanding due to concurrent neurovascular injuries. An open dislocation without fracture is very rare and it should be treated with immediate intervention, an effective teamwork and good rehabilitation.     

Minimal medial epicondylectomy and decompression for cubital tunnel syndrome.

Sixty-four patients (66 elbows) treated for refractory cubital tunnel syndrome had minimal medial epicondylectomy and in situ decompression to minimize the potential disadvantages of classic medial epicondylectomy. After a mean followup of 27 months results were excellent in 27 patients (44%), good in 23 patients (35%), fair in 10 patients (15%), and poor in four patients (6%). No ulnar nerve palsy, ulnar nerve subluxation, or medial elbow instability were seen. The main complaint of patients regarding the procedure was tenderness at the osteotomy site. The results show that minimal medial epicondylectomy and in situ decompression of the ulnar nerve is a safe and effective method to treat patients with cubital tunnel syndrome. This procedure minimizes the disadvantage of medial instability and recurrent symptoms attributable to nerve trauma after a classic medial epicondylectomy.     

Correction of axial and rotational alignment after medial and lateral releases during balanced gap TKA: A clinical study of 54 patients

Background and purpose

Restoration of mechanical alignment after total knee arthroplasty can be achieved with ligament releases. Several previously described sequences and results achieved with cadaver knees, with measured resection implantation techniques, may not be applied to the balanced gap technique. We investigated the peroperative effect of stepwise soft tissue releases following the “tightest structure first” on leg axis in extension and femur rotation in flexion.

Methods

During PCL-retaining total knee arthroplasty (TKA), using a balanced gap technique in 54 patients we determined the effect of each ligament release using a navigation system while the knee was distracted with a tensor in extension and flexion. The effect on alignment in extension and on femoral rotation in flexion was measured for each release separately.

Results

In more than half of the patients, one or more ligament releases were necessary. Release of the posteromedial condyle led to a minor effect on leg axis in extension and femoral rotation in flexion, release of the superficial medial collateral ligament to a few degrees, mainly in extension. Release of the iliotibial tract led to a small correction of leg alignment in extension. There was no statistically significant difference in the alignment-correcting effect of a release dependent upon the sequence in which the structure was released.

Interpretation

In PCL-retaining TKA, a stepwise “tightest structure first” protocol for ligament releases in extension with the balanced gap technique results in effective, gradual, alignment correction in extension, and limited femoral rotating effects in flexion.     

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.     

肘部尺神经卡压与尺神经半脱位的诊疗进展

肘部尺神经卡压也称为肘管综合征,可造成手部一系列功能障碍,是最常见的上肢神经卡压症之一。尺神经脱位及半脱位为尺神经卡压的影响因素。尺神经卡压按McGowan分级分为Ⅰ、Ⅱ、Ⅲ级。Ⅰ级首选保守治疗 Ⅱ、Ⅲ级保守治疗效果欠佳,多需要手术治疗。手术方式主要有尺神经原位松解术（包括肱骨内髁切除术）、粘膜下尺神经前置术、肌下尺神经前置术及肌内尺神经前置术等,其中原位松解手术操作相对简单,但对于尺神经卡压伴有尺神经脱位者多属禁忌,应首选尺神经前置术。     

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.