Lateral antebrachial cutaneous nerve compression after traumatic rupture of the long head of the biceps: a case series

Abstract

Lateral antebrachial cutaneous (LABC) nerve compression is a rare but debilitating injury. There are limited data on the association of LABC nerve compression and proximal biceps rupture. We theorized that because of distal migration, the biceps muscle and tendon cause compression on the nerve. We present 2 cases in which patients had proximal biceps ruptures with tendon retraction and developed neurologic symptoms associated with the LABC nerve. To demonstrate our theory, we performed a cadaveric experiment. After making an incision to expose the entire biceps muscle and the musculocutaneous nerve and its branch into the LABC nerve, we marked each structure in 2-cm increments with a marking pen. The long head of the biceps was then cut to simulate a proximal biceps rupture. The relationship between the 3 structures was then studied, showing no change in position of the musculocutaneous nerve or LABC nerve. The biceps muscle and tendon had migrated distally toward the LABC nerve, demonstrating compression of the nerve. Proximal biceps tears commonly occur from trauma as well as iatrogenically after a biceps tenotomy for treatment of biceps tendinopathy. However, it is unusual for neuropathy of the LABC nerve to occur. Patients who develop neuropathy associated with the LABC nerve after a proximal biceps rupture can be effectively treated with LABC nerve decompression and biceps plasty. We found that this was an effective surgical treatment of LABC neuropathy without the need for proximal biceps tenodesis.