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Lateral Antebrachial Cutaneous Neuropathy Following the Long Head of the Biceps Rupture
SCIENTIFIC ARTICLE
Lateral Antebrachial Cutaneous Neuropathy Following the Long Head of the Biceps Rupture David M. Brogan, MD, Allen T. Bishop, MD, Robert J. Spinner, MD, Alexander Y. Shin, MD Lateral antebrachial cutaneous neuropathies present as purely sensory lesions, manifesting as elbow pain or dysesthetic pain over the lateral forearm. Classically, entrapment of the lateral antebrachial cutaneous nerve has been documented at the lateral edge of the biceps tendon as it exits the deep fascia in the antecubital fossa. We report a case of lateral antebrachial cutaneous nerve traction neuritis, rather than entrapment, resulting from a rupture of the long head of the biceps. The biceps displaced the nerve laterally, resulting in sensory loss and severe allodynia. The patient’s symptoms were relieved with proximal biceps tenodesis. (J Hand Surg 2012;37A:673–676. Copyright © 2012 by the American Society for Surgery of the Hand. All rights reserved.) Key words Distal biceps, lateral antebrachial cutaneous neuropathy, rupture.
ATERAL ANTEBRACHIAL CUTANEOUS (LABC) nerve palsies are rare and are usually heralded by dysesthetic pain over the lateral aspect of the forearm. They are generally thought to result from compression of the nerve at the bicipital aponeurosis.1 We describe an LABC traction neuropathy resulting from lateral displacement of the nerve by the ruptured long head of the biceps muscle.
L
CASE DESCRIPTION A healthy, 49-year-old, left-handed man presented to our brachial plexus clinic for evaluation of a persistent burning sensation in the lateral left forearm. The pain began approximately 9 months before presentation during a training activity as a law enforcement officer. The left shoulder was pulled into extension while the head was tilted toward the contralateral side. He heard a popping sound coming from the shoulder and immediately noted a left distal biceps bulge with subsequent From the Mayo Clinic, Rochester, MN. Received for publication June 24, 2011; accepted in revised form January 19, 2012. No benefits in any form have been received or will be received related directly or indirectly to the subject of this article. Corresponding author: Alexander Y. Shin, MD, Mayo Clinic, 200 First Street SW, Rochester, MN 55905; e-mail: [email protected]. 0363-5023/12/37A04-0006$36.00/0 doi:10.1016/j.jhsa.2012.01.023
development of paresthesias and burning pain in the lateral forearm and palm. The hand paresthesias resolved relatively quickly; however, the burning forearm pain persisted and was exacerbated with forearm rotation and clenching of the fist. The cutaneous hypersensitivity was so severe that he removed all of his forearm hair and was unable to wear long-sleeved clothing. He showed no signs of a motor deficit. Before to the consultation, the patient had tried oral steroids, nonsteroidal anti-inflammatory medications, stellate ganglion blocks, and cervical epidural injections, without benefit. He had also tried numerous neuropathic pain medications and at the time of presentation found some mild relief with twice daily dosing of pregabalin. A musculocutaneous nerve block at an outside facility relieved the symptoms for a few hours. At the initial examination, a proximal biceps rupture was evident by inspection (Fig. 1) and was confirmed with an upper extremity magnetic resonance imaging scan. Most notably, the pain could be relieved by pulling the retracted, ruptured biceps head proximally. He experienced a positive Tinel sign with percussion tenderness along the course of the LABC just distal to the elbow; however, this was not present at the usual entrapment site near the lateral border of the biceps tendon. Electrophysiologic testing demonstrated reduced LABC amplitudes (4 V compared with 16 V on
© ASSH 䉬 Published by Elsevier, Inc. All rights reserved. 䉬 673
674
LATERAL ANTEBRACHIAL CUTANEOUS NEUROPATHY
FIGURE 1: Distal bulging of the biceps mass is evident.
FIGURE 2: Musculocutaneous nerve as it branches into the LABC nerve. During surgical exposure, the LABC was found to be displaced lateral to its normal course beneath the biceps. When the biceps tendon was pulled proximally, traction on the nerve was decreased.
the contralateral side). There was no evidence of proximal involvement of the musculocutaneous nerve motor branches to the biceps or brachialis. At the time of surgery we made a medial arm incision along the posterior border of the biceps and then identified the musculocutaneous nerve and its terminal biceps, brachialis, and LABC branches (Fig. 2). The musculocutaneous nerve was displaced laterally. We undertook an exploration to identify any sites of compression, but we found none. The rupture of the long head of the biceps tendon was confirmed, with the
tendon found to be attenuated and shortened. During proximal advancement of the long head of the biceps, it became clear that the shortened biceps was causing a mass effect on the nerve. When the biceps was pulled proximally, the fascia and tissue surrounding the nerve relaxed, and the nerve returned to its normal location, which diminished the stretch placed on the nerve in the distal arm (Fig. 3). Therefore, we performed a proximal biceps tenodesis using drill holes and suture. We also performed neurolysis of the LABC nerve. Passive range of motion of the elbow demonstrated a secure biceps repair with no kinking, compression, or traction on the nerve. Within hours of the surgical procedure, the patient’s allodynia improved notably, and showed continued improvement over time. Six weeks postoperatively, he noted only mild hypersensitivity in a much smaller area of the lateral forearm and no longer required pain medication. At four and a half months postoperatively, he still had a narrow area of dysesthetic pain, approximately 1.5 ⫻ 4 cm. His Tinel sign had progressed to the wrist and he was back to performing all usual activities as a law enforcement officer. At 10 months postoperatively, the area of dysesthetic pain was unchanged. DISCUSSION The musculocutaneous nerve arises from the lateral cord of the brachial plexus beneath the clavicle and penetrates the coracobrachialis muscle in the proximal arm. From there, the nerve divides into terminal biceps and brachialis motor branches and the LABC nerve, a sensory nerve. The LABC lies deep to the distal biceps muscle and tendon until the nerve pierces the deep fascia just proximal to the elbow joint, to lie lateral to the distal biceps tendon.2 It then passes behind the cephalic vein and divides into volar and dorsal branches, providing sensation to radial-volar and radialdorsal aspects of the forearm.1,3 Disorders of the LABC nerve have commonly been divided into compressive neuropathies and sharp injuries (traumatic or iatrogenic). Bassett and Nunley1 first described compression of the LABC nerve in a series of 11 patients presenting with anterolateral elbow pain. The distinguishing characteristic of acute versus chronic nerve injuries in this series was the location of the pain. Patients with acute injury presented with dysesthetic pain in the forearm, but those with chronic symptoms experienced vague elbow discomfort without cutaneous forearm sensory symptoms. Intraoperatively, the LABC nerve was compressed between the biceps tendon and the brachialis fascia. Surgical excision of a wedge of biceps tendon over the area of
JHS 䉬 Vol A, April
LATERAL ANTEBRACHIAL CUTANEOUS NEUROPATHY
675
FIGURE 3: A Typical course of musculocutaneous and LABC nerve with normal biceps. Dashed line indicates nerve traveling deep to the muscle. B Lateral displacement and resulting traction injury of LABC from ruptured biceps. C Resolution of displacement and traction injury after biceps tenodesis.
compression provided symptomatic relief. The longterm follow-up of these patients demonstrated continued complete pain relief.4 Entrapment may also occur at the level of the superficial antebrachial fascia of the forearm,5 and these patients present with dysesthesias over the lateral forearm and occasionally with lateral elbow pain.6 Other isolated causes of LABC neuropathy have included phlebotomy,7 pull-ups during military training,8 and anesthesia positioning.9 Initial conservative treatment of these injuries can include splinting, rest, anti-inflammatories, steroid injections, and ultrasound.5 Traditionally, surgery has consisted of decompression of the nerve with excision of the biceps aponeurosis. Much of the literature on LABC neuropathies and biceps rupture focuses on surgical complications after repair and tenodesis of the distal biceps.10 Two cases of LABC neuropathy associated with biceps tendon trauma have been reported: 1 with a rupture of the long head and a second with an avulsion of the distal insertion.11 In the former, excision of posttraumatic fibrosis was undertaken, and in the latter, neurolysis and reattachment of the tendon using tendon graft was performed. Our case illustrates another mechanism for LABC neuritis: traction neuritis resulting from mass
effect of proximal biceps rupture and retraction. Although a neurolysis was performed in addition to the biceps tenodesis, it may have been unnecessary. It seems unlikely that neural entrapment from scar tissue was responsible for this patient’s symptoms. The fact that the patient could relieve his pain at the initial clinic visit by milking the biceps head proximally suggests that the biceps tenodesis contributed most to his clinical improvement. REFERENCES 1. Bassett F, Nunley J. Compression of the musculocutaneous nerve at the elbow. J Bone Joint Surg 1982;64A:1050 –1052. 2. Johnson EO, Vekris MD, Zoubos AB, Soucacos PN. Neuroanatomy of the brachial plexus: the missing link in the continuity between the central and peripheral nervous systems. Microsurgery 2006;26:218 – 229. 3. Waldman SD. Pain review. Philadelphia: WB Saunders, 2009:99. 4. Davidson JJ, Bassett FH, Nunley JA. Musculocutaneous nerve entrapment revisited. J Shoulder Elbow Surg 1998;7:250 –255. 5. Belzile E, Cloutier D. Entrapment of the lateral antebrachial cutaneous nerve exiting through the forearm fascia. J Hand Surg 2001; 26A:64 – 67. 6. Naam NH, Massoud HA. Painful entrapment of the lateral antebrachial cutaneous nerve at the elbow. J Hand Surg 2004;29A:1148 – 1153. 7. Stitik TP, Foye PM, Nadler SF, Brachman GO. Phlebotomy-related lateral antebrachial cutaneous nerve injury. Am J Phys Med Rehabil 2001;80:230 –234.
JHS 䉬 Vol A, April
676
LATERAL ANTEBRACHIAL CUTANEOUS NEUROPATHY
8. Yildiz N, Kilinc B, Ardic F. A soldier with lateral antebrachial cutaneous neuropathy: malingering or fact? Turk J Phys Med Rehab 2010;56:145–147. 9. Judge A, Fecho K. Lateral antebrachial cutaneous neuropathy as a result of positioning while under general anesthesia. Anesth Analg 2010;110:122–124.
10. Kelly EW, Morrey BF, O’Driscoll SW. Complications of repair of the distal biceps tendon with the modified two-incision technique. J Bone Joint Surg 2000;82A:1575–1581. 11. Dailiana ZH, Roulot E, Le Viet D. Surgical treatment of compression of the lateral antebrachial cutaneous nerve. J Bone Joint Surg 2000; 82B:420 – 423.
JHS 䉬 Vol A, April
Lateral Antebrachial Cutaneous Neuropathy Following the Long Head of the Biceps Rupture David M. Brogan, MD, Allen T. Bishop, MD, Robert J. Spinner, MD, Alexander Y. Shin, MD Lateral antebrachial cutaneous neuropathies present as purely sensory lesions, manifesting as elbow pain or dysesthetic pain over the lateral forearm. Classically, entrapment of the lateral antebrachial cutaneous nerve has been documented at the lateral edge of the biceps tendon as it exits the deep fascia in the antecubital fossa. We report a case of lateral antebrachial cutaneous nerve traction neuritis, rather than entrapment, resulting from a rupture of the long head of the biceps. The biceps displaced the nerve laterally, resulting in sensory loss and severe allodynia. The patient’s symptoms were relieved with proximal biceps tenodesis. (J Hand Surg 2012;37A:673–676. Copyright © 2012 by the American Society for Surgery of the Hand. All rights reserved.) Key words Distal biceps, lateral antebrachial cutaneous neuropathy, rupture.
ATERAL ANTEBRACHIAL CUTANEOUS (LABC) nerve palsies are rare and are usually heralded by dysesthetic pain over the lateral aspect of the forearm. They are generally thought to result from compression of the nerve at the bicipital aponeurosis.1 We describe an LABC traction neuropathy resulting from lateral displacement of the nerve by the ruptured long head of the biceps muscle.
L
CASE DESCRIPTION A healthy, 49-year-old, left-handed man presented to our brachial plexus clinic for evaluation of a persistent burning sensation in the lateral left forearm. The pain began approximately 9 months before presentation during a training activity as a law enforcement officer. The left shoulder was pulled into extension while the head was tilted toward the contralateral side. He heard a popping sound coming from the shoulder and immediately noted a left distal biceps bulge with subsequent From the Mayo Clinic, Rochester, MN. Received for publication June 24, 2011; accepted in revised form January 19, 2012. No benefits in any form have been received or will be received related directly or indirectly to the subject of this article. Corresponding author: Alexander Y. Shin, MD, Mayo Clinic, 200 First Street SW, Rochester, MN 55905; e-mail: [email protected]. 0363-5023/12/37A04-0006$36.00/0 doi:10.1016/j.jhsa.2012.01.023
development of paresthesias and burning pain in the lateral forearm and palm. The hand paresthesias resolved relatively quickly; however, the burning forearm pain persisted and was exacerbated with forearm rotation and clenching of the fist. The cutaneous hypersensitivity was so severe that he removed all of his forearm hair and was unable to wear long-sleeved clothing. He showed no signs of a motor deficit. Before to the consultation, the patient had tried oral steroids, nonsteroidal anti-inflammatory medications, stellate ganglion blocks, and cervical epidural injections, without benefit. He had also tried numerous neuropathic pain medications and at the time of presentation found some mild relief with twice daily dosing of pregabalin. A musculocutaneous nerve block at an outside facility relieved the symptoms for a few hours. At the initial examination, a proximal biceps rupture was evident by inspection (Fig. 1) and was confirmed with an upper extremity magnetic resonance imaging scan. Most notably, the pain could be relieved by pulling the retracted, ruptured biceps head proximally. He experienced a positive Tinel sign with percussion tenderness along the course of the LABC just distal to the elbow; however, this was not present at the usual entrapment site near the lateral border of the biceps tendon. Electrophysiologic testing demonstrated reduced LABC amplitudes (4 V compared with 16 V on
© ASSH 䉬 Published by Elsevier, Inc. All rights reserved. 䉬 673
674
LATERAL ANTEBRACHIAL CUTANEOUS NEUROPATHY
FIGURE 1: Distal bulging of the biceps mass is evident.
FIGURE 2: Musculocutaneous nerve as it branches into the LABC nerve. During surgical exposure, the LABC was found to be displaced lateral to its normal course beneath the biceps. When the biceps tendon was pulled proximally, traction on the nerve was decreased.
the contralateral side). There was no evidence of proximal involvement of the musculocutaneous nerve motor branches to the biceps or brachialis. At the time of surgery we made a medial arm incision along the posterior border of the biceps and then identified the musculocutaneous nerve and its terminal biceps, brachialis, and LABC branches (Fig. 2). The musculocutaneous nerve was displaced laterally. We undertook an exploration to identify any sites of compression, but we found none. The rupture of the long head of the biceps tendon was confirmed, with the
tendon found to be attenuated and shortened. During proximal advancement of the long head of the biceps, it became clear that the shortened biceps was causing a mass effect on the nerve. When the biceps was pulled proximally, the fascia and tissue surrounding the nerve relaxed, and the nerve returned to its normal location, which diminished the stretch placed on the nerve in the distal arm (Fig. 3). Therefore, we performed a proximal biceps tenodesis using drill holes and suture. We also performed neurolysis of the LABC nerve. Passive range of motion of the elbow demonstrated a secure biceps repair with no kinking, compression, or traction on the nerve. Within hours of the surgical procedure, the patient’s allodynia improved notably, and showed continued improvement over time. Six weeks postoperatively, he noted only mild hypersensitivity in a much smaller area of the lateral forearm and no longer required pain medication. At four and a half months postoperatively, he still had a narrow area of dysesthetic pain, approximately 1.5 ⫻ 4 cm. His Tinel sign had progressed to the wrist and he was back to performing all usual activities as a law enforcement officer. At 10 months postoperatively, the area of dysesthetic pain was unchanged. DISCUSSION The musculocutaneous nerve arises from the lateral cord of the brachial plexus beneath the clavicle and penetrates the coracobrachialis muscle in the proximal arm. From there, the nerve divides into terminal biceps and brachialis motor branches and the LABC nerve, a sensory nerve. The LABC lies deep to the distal biceps muscle and tendon until the nerve pierces the deep fascia just proximal to the elbow joint, to lie lateral to the distal biceps tendon.2 It then passes behind the cephalic vein and divides into volar and dorsal branches, providing sensation to radial-volar and radialdorsal aspects of the forearm.1,3 Disorders of the LABC nerve have commonly been divided into compressive neuropathies and sharp injuries (traumatic or iatrogenic). Bassett and Nunley1 first described compression of the LABC nerve in a series of 11 patients presenting with anterolateral elbow pain. The distinguishing characteristic of acute versus chronic nerve injuries in this series was the location of the pain. Patients with acute injury presented with dysesthetic pain in the forearm, but those with chronic symptoms experienced vague elbow discomfort without cutaneous forearm sensory symptoms. Intraoperatively, the LABC nerve was compressed between the biceps tendon and the brachialis fascia. Surgical excision of a wedge of biceps tendon over the area of
JHS 䉬 Vol A, April
LATERAL ANTEBRACHIAL CUTANEOUS NEUROPATHY
675
FIGURE 3: A Typical course of musculocutaneous and LABC nerve with normal biceps. Dashed line indicates nerve traveling deep to the muscle. B Lateral displacement and resulting traction injury of LABC from ruptured biceps. C Resolution of displacement and traction injury after biceps tenodesis.
compression provided symptomatic relief. The longterm follow-up of these patients demonstrated continued complete pain relief.4 Entrapment may also occur at the level of the superficial antebrachial fascia of the forearm,5 and these patients present with dysesthesias over the lateral forearm and occasionally with lateral elbow pain.6 Other isolated causes of LABC neuropathy have included phlebotomy,7 pull-ups during military training,8 and anesthesia positioning.9 Initial conservative treatment of these injuries can include splinting, rest, anti-inflammatories, steroid injections, and ultrasound.5 Traditionally, surgery has consisted of decompression of the nerve with excision of the biceps aponeurosis. Much of the literature on LABC neuropathies and biceps rupture focuses on surgical complications after repair and tenodesis of the distal biceps.10 Two cases of LABC neuropathy associated with biceps tendon trauma have been reported: 1 with a rupture of the long head and a second with an avulsion of the distal insertion.11 In the former, excision of posttraumatic fibrosis was undertaken, and in the latter, neurolysis and reattachment of the tendon using tendon graft was performed. Our case illustrates another mechanism for LABC neuritis: traction neuritis resulting from mass
effect of proximal biceps rupture and retraction. Although a neurolysis was performed in addition to the biceps tenodesis, it may have been unnecessary. It seems unlikely that neural entrapment from scar tissue was responsible for this patient’s symptoms. The fact that the patient could relieve his pain at the initial clinic visit by milking the biceps head proximally suggests that the biceps tenodesis contributed most to his clinical improvement. REFERENCES 1. Bassett F, Nunley J. Compression of the musculocutaneous nerve at the elbow. J Bone Joint Surg 1982;64A:1050 –1052. 2. Johnson EO, Vekris MD, Zoubos AB, Soucacos PN. Neuroanatomy of the brachial plexus: the missing link in the continuity between the central and peripheral nervous systems. Microsurgery 2006;26:218 – 229. 3. Waldman SD. Pain review. Philadelphia: WB Saunders, 2009:99. 4. Davidson JJ, Bassett FH, Nunley JA. Musculocutaneous nerve entrapment revisited. J Shoulder Elbow Surg 1998;7:250 –255. 5. Belzile E, Cloutier D. Entrapment of the lateral antebrachial cutaneous nerve exiting through the forearm fascia. J Hand Surg 2001; 26A:64 – 67. 6. Naam NH, Massoud HA. Painful entrapment of the lateral antebrachial cutaneous nerve at the elbow. J Hand Surg 2004;29A:1148 – 1153. 7. Stitik TP, Foye PM, Nadler SF, Brachman GO. Phlebotomy-related lateral antebrachial cutaneous nerve injury. Am J Phys Med Rehabil 2001;80:230 –234.
JHS 䉬 Vol A, April
676
LATERAL ANTEBRACHIAL CUTANEOUS NEUROPATHY
8. Yildiz N, Kilinc B, Ardic F. A soldier with lateral antebrachial cutaneous neuropathy: malingering or fact? Turk J Phys Med Rehab 2010;56:145–147. 9. Judge A, Fecho K. Lateral antebrachial cutaneous neuropathy as a result of positioning while under general anesthesia. Anesth Analg 2010;110:122–124.
10. Kelly EW, Morrey BF, O’Driscoll SW. Complications of repair of the distal biceps tendon with the modified two-incision technique. J Bone Joint Surg 2000;82A:1575–1581. 11. Dailiana ZH, Roulot E, Le Viet D. Surgical treatment of compression of the lateral antebrachial cutaneous nerve. J Bone Joint Surg 2000; 82B:420 – 423.
JHS 䉬 Vol A, April