Available online at www.sciencedirect.com
Surgical Neurology 71 (2009) 709 – 712 www.surgicalneurology-online.com
Neuropathy
Posttraumatic immobilization in flexion of a congenital valgus elbow and cubital tunnel syndrome—case report Federico Di Rocco, MD, Francesco Doglietto, MD, Tommaso Tufo, MD, Alessandro Ciampini, MD, Liverana Lauretti, MD, Eduardo Fernandez, MD⁎ Department of Neurosurgery, Catholic University School of Medicine, Rome 00168, Italy Received 14 March 2007; accepted 5 January 2008
Abstract
Background: Elbow trauma, cubitus valgus deformity, and prolonged flexion of the elbow are recognized risk factors for ulnar nerve entrapment. Case Description: The 3 conditions coincided in the present case. In fact, a 36-year-old woman had a bilateral severe congenital cubitus valgus. A trauma of the right elbow caused luxation and supracondylar humeral fracture for which the joint was fixed in flexion at 90° for 1 month. The patient developed a severe ulnar nerve entrapment syndrome that did not respond to several months of physiotherapy and active mobilization of the elbow. The symptoms recovered after surgical decompression and anterior subcutaneous transposition of the nerve. Conclusions: The present case illustrates how the development of a cubital tunnel syndrome should be considered as the expected outcome of a long immobilization in flexion of an elbow with a severe cubitus valgus. A simple subcutaneous anterior transposition of the ulnar nerve might be recommended before a long immobilization of a cubitus valgus elbow is performed. © 2009 Elsevier Inc. All rights reserved.
Keywords:
Ulnar entrapment; Supracondylar fracture; Peripheral nerve; Iatrogenic cubital tunnel syndrome; Cubitus valgus
1. Introduction Ulnar neuropathy at the cubital tunnel is the second most common peripheral nerve entrapment syndrome and was described for the first time by Panas [7] in 1898. In the normal elbow, flexion causes an increase in intraneural pressure by 6 times in the ulnar nerve, a shape change from oval to elliptical of the cubital tunnel which narrows by 55%, and a corresponding sliding and stretching of the ulnar nerve [1,2]. Such increase in intraneural and extraneural pressures, during elbow flexion, is usually well tolerated by the ulnar nerve. In elbow deformities, like cubitus valgus, the increase in intraneural and extraneural pressures during elbow flexion is higher, being proportional to the degree of
⁎ Corresponding author. Tel.: +39 06 30154120; fax: +39 06 8072258. E-mail address:
[email protected] (E. Fernandez). 0090-3019/$ – see front matter © 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.surneu.2008.01.020
the deformity. Flexion of the elbow is indeed one of the most common etiopathogenetic mechanisms of the cubital tunnel syndrome, either acquired (accidental or occupational trauma) or congenital (like cubitus valgus) [1-3,5,6]. On this basis, what should be the consequences on the ulnar nerve of a prolonged flexion of an elbow with a severe valgus deformity? We present the case of a young woman affected by a bilateral severe congenital cubitus valgus. After a trauma of the right elbow (luxation and humeral supracondylar fracture), fixation of the joint in flexion at 90° for 30 days was necessary. Whereas immediately after the trauma no neurologic deficit was present, at the end of the period of immobilization a severe ulnar nerve palsy was evident. Would it in this case be easy to predict an entrapment of the ulnar nerve during the 30-day fixation in flexion at 90° of the elbow with such severe valgus deformity? With a positive answer, should a preventive anterior
710
F. Di Rocco et al. / Surgical Neurology 71 (2009) 709–712
Fig. 1. X-ray of the right valgus elbow. A: Elbow subluxation; B: correction of the subluxation reveals a supracondylar fracture; C: the external apparatus immobilizes the elbow in flexion at 90°.
transposition of the ulnar nerve be performed before the orthopedic treatment? 2. Case report A 36-year-old woman presented to our department affected by a severe right cubital tunnel syndrome. Six months before, she had sustained a fall from a bike resulting in an elbow luxation (Fig. 1A). In the emergency department of another hospital, the elbow luxation was reduced and an underlying humeral supracondylar fracture (Fig. 1B) was noted and treated by immobilizing the elbow in flexion at 90° for 30 days using an external apparatus (Fig. 1C). Four days later, a 1 h/d mobilization of the elbow was initiated. The patient reported that immediately after the trauma she did not notice any motor changes of the hand; however, 1 week later she began to feel a certain weakness in the extension of the IV and V fingers, which remained unnoticed by her doctors. After 30 days of elbow flexion at 90°, the external apparatus was removed; a claw deformity of the right hand and an intrinsic muscle atrophy were evident. The patient followed a program of physiotherapy. An
electromyography showed signs of denervation of the ulnar-dependent muscles of the hand. After several months of active mobilization of the elbow and physiotherapy, the claw hand, with a reduced force, was still present. A new electromyography showed fibrillations of the flexor carpi ulnaris, abductor digiti minimi, and first dorsal interosseous muscles, and no action potential could be detected after voluntary contraction. The patient was admitted to our day surgery and clinical examination showed a bilateral severe cubitus valgus (Fig. 2A) corresponding to a humerus-elbow-wrist angle [5] measured on anteroposterior radiographs of 36° on the right and 30° on the left. A marked atrophy (Fig. 2B) and strength reduction of the intrinsic hand muscles were evident: the first dorsal interosseous, the abductor digiti minimi, and the flexor digitorum profundus of the fourth and fifth digits had a strength of 0/5. Hypesthesia and paresthesias were present into the ulnar side of the hand both ventrally and dorsally; no pain was present. Tinel's sign at the elbow was positive. At surgery, under local anesthesia, severe compression and stretching of the ulnar nerve were demonstrated to occur, as expected, during flexion of the
Fig. 2. A: The severe bilateral cubitus valgus; B: the cubital tunnel syndrome features with the right claw hand and muscle atrophy.
F. Di Rocco et al. / Surgical Neurology 71 (2009) 709–712
711
Fig. 3. Intraoperative findings. A: The ulnar nerve during extension of the elbow; B: the nerve stretched and compressed during flexion of the elbow; medial epicondyle (⁎); C: the ulnar nerve anteriorly transposed is not compressed and stretched during flexion of the elbow.
elbow (Fig. 3). The nerve was transposed anterior to the medial epicondyle in a subcutaneous site. The postoperative course was uneventful. At the 6-month follow-up, the patient showed resolution of the claw deformity of the hand and significant improvement of its strength: the first dorsal interosseous, the abductor digiti minimi, and the flexor digitorum profundus of the fourth and fifth digits had a strength of 2-3/5; at the 3-year follow-up, the patient showed continued improvement with a 3-4/5 motor grade of the same muscles. The hypesthesia and paresthesias, as well as the Tinel's sign, were also resolved. At 3 years of follow-up, electrodiagnostic studies documented a marked improvement of the conduction velocity of the ulnar nerve at the elbow, which, however, remains slightly longer than normal (motor conduction velocity, 36 m/s—contralateral, 46 m/s; sensitivity conduction velocity, 47 m/s—contralateral, 52 m/s). 3. Discussion Cubitus valgus deformity can be either acquired, as a complication of elbow fracture, or congenital as in the present case. In a surgical orthopedic series of 13 patients with acquired cubitus valgus, the humerus-elbow-wrist angle, measured on anteroposterior radiographs, ranged from 29° to 51° (average, 35.7°); 5 of these patients were affected by a 6- to 12-month-lasting tardy ulnar nerve palsy, which was treated by subcutaneous anterior transposition of the ulnar nerve [5]. Our patient had a congenital bilateral cubitus valgus deformity; the humerus-elbow-wrist angle was 30° on the left and 36° on the right, the right elbow being the injured one. Cubitus valgus represents an important factor favoring the development of a cubital tunnel syndrome. Although cubital tunnel syndrome does not develop in all cubitus valgus, a trauma of an elbow with severe cubitus valgus increases the probability of such a syndrome developing. If flexion at 90° of such an elbow is necessary for a long time, the probability of an ulnar neuropathy increases further.
Compression and stretching of the ulnar nerve occur during elbow flexion, as didactically shown in Fig. 3, and their entity depends on normal or deformed anatomy. This concept is applied to cases of mild cubital tunnel syndrome when a conservative treatment can be based on patient education to avoid provocative activities like protracted periods of elbow flexion [6]. Therefore, it seems reasonable that in cases such as ours an anterior transposition of the ulnar nerve [4] could be considered before the long-term immobilization of a similarly deformed and traumatized elbow. Other authors have reported the use of simple decompression, submuscular transposition, and medial epicondylectomy for the surgical treatment of ulnar neuropathy at the elbow [8]. In our opinion, although simple decompression does not prevent the injury mechanism of stretching of the ulnar nerve during elbow flexion, both submuscular nerve transposition and medial epicondylectomy are either more complex procedures or cause more reactive scar tissue than subcutaneous transposition. In our department, subcutaneous anterior transposition of the ulnar nerve is a safe and effective routine operation performed in local anesthesia in patients with more severe cubital tunnel syndrome. Although this is a single report, we think that if it is necessary to immobilize an elbow affected by a severe cubitus valgus in flexion at 90° for a long time, the possibility of performing a preventive anterior subcutaneous transposition of the ulnar nerve should be taken into consideration. Flexion of a severe cubitus valgus unavoidably will cause deleterious stretching and compression of the ulnar nerve. In this particular case, having seen the patient 6 months after the initial trauma (treated in another hospital) at that time, we were only able to treat the ulnar nerve palsy by an anterior subcutaneous transposition. However, we think that such treatment should be considered early, after the onset of clinical symptoms, or even as a preventive treatment, when a prolonged immobilization in flexion of an elbow affected by severe cubital valgus deformity is dictated by orthopedic necessities.
712
F. Di Rocco et al. / Surgical Neurology 71 (2009) 709–712
4. Conclusions Congenital cubitus valgus represents a particularly important predisposing risk factor for ulnar neuropathy. During flexion of any elbow, stretching and compression of the ulnar nerve ensue, being minimal in a normal elbow and maximal in a severe valgus elbow. In any individual with significant cubitus valgus, a forced flexion of the elbow will be followed in a few minutes by numbness and tingling in the ulnar border of the hand as a clinical demonstration of ulnar nerve entrapment. After trauma of an elbow with severe valgus deformity in which a prolonged immobilization of the joint in flexion is required, it appears reasonable to recommend a simple subcutaneous anterior transposition of the ulnar nerve as a prophylactic procedure to prevent a highly probable ulnar nerve palsy. References [1] Bozentka DJ. Cubital tunnel syndrome pathophysiology. Clin Orthop 1998;351:90-4. [2] Cutts S. Cubital tunnel syndrome. Postgrad Med J 2007;83:28-31. [3] Descatha A, Leclerc A, Chastang JF, et al. Study Group on Repetitive Work. Incidence of ulnar nerve entrapment at the elbow in repetitive work. Scand J Work Environ Health 2004;30:234-40. [4] Kim DH, Han K, Tiel RL, et al. Surgical outcomes of 654 ulnar nerve lesions. J Neurosurg 2003;98:993-1004. [5] Kim HT, Lee JS, Yoo CI. Management of cubitus varus and valgus. J Bone Joint Surg 2005;87-A:771-80. [6] Padua L, Aprile I, Caliandro P, Foschini M, Mazza S, Tonali P. Natural history of ulnar entrapment at elbow. Clin Neurophysiol 2002;113: 1980-4. [7] Panas J. Sur une cause peu connue de paralysie du nerf cubital. Arch Gen Med 1878;2:5-22. [8] Posner MA. Compressive ulnar neuropathies at the elbow: II. treatment. J Am Acad Orthop Surg 1998;6:289-97.
Commentary In this informative case report, the authors have presented an unusual patient who had a severe posttraumatic ulnar entrapment neuropathy. Through a constellation of conspiring factors, this patient's ulnar nerve was compromised by a congenital cubitus valgus deformity, severe elbow trauma with a fracture/subluxation, and then iatrogenic “insult to injury” with prolonged fixation in flexion. All of these factors served to stretch and constrict the ulnar nerve within the postcondylar groove, and the patient had rapid deteriora-
tion in ulnar nerve function. At 1 week after immobilization, the patient already demonstrated weakness of the ulnarinnervated lumbricales, and by 1 month a claw-hand deformity was evident. The patient's physicians elected to pursue a conservative management program, and the authors did not have the opportunity to evaluate and surgically intervene until 6 months later. Fortunately, despite the severity and duration of the ulnar neuropathy, the patient did improve after anterior subcutaneous transposition of the ulnar nerve. The authors suggested that in patients with this combination of cubitus valgus deformity, elbow trauma, and forced immobilization in flexion, a prophylactic anterior subcutaneous transposition should be performed. This case illustrates several management challenges. Ideally, this patient should have been referred to a peripheral nerve specialist for evaluation much sooner. By the time of the referral in this case, the injury to the ulnar nerve was severe and the deficit was profound. Although the outcome seems to have been favorable, most patients who present with atrophy and claw-hand deformity do not recover normal ulnar nerve function. On the other hand, it is difficult to justify prophylactic surgery in most cases, as the prediction of a future deficit is uncertain and there is some risk associated with surgery, albeit small. Other options for management would include careful, serial clinical examination and early surgical intervention at the onset of symptoms or signs in the ulnar nerve distribution. In this case, one might even consider early electrodiagnostic examination, as there might have been an underlying subclinical ulnar entrapment neuropathy due to the severe valgus deformity; slowing of conduction and/or signs of denervation might then prompt either closer clinical monitoring of nerve function or early surgical intervention. The choice of operative technique for treatment of ulnar entrapment neuropathy at the elbow has been debated for years, and the favorable outcome in this case speaks for itself. However, several randomized, controlled trials have now shown that simple in situ ulnar nerve decompression is the procedure of choice in routine cases of ulnar entrapment neuropathy at the elbow. The present case is anything but routine and, therefore, we agree that some form of anterior transposition, subcutaneous or submuscular, can be justified.
Eric L. Zager, MD Department of Neurosurgery University of Pennsylvania Hospital Philadelphia, PA 19104, USA
