Differentiating C8–T1 Radiculopathy from Ulnar Neuropathy: A Survey of 24 Spine Surgeons

Study Design Questionnaire. Objective To evaluate the ability of spine surgeons to distinguish C8–T1 radiculopathies from ulnar neuropathy. Methods Twenty-four self-rated “experienced” cervical spine surgeons completed a questionnaire with the following items. (1) If the ulnar nerve is cut at the elbow, which of the following would be numb: ulnar forearm, small and ring fingers; only the ulnar forearm; only the small and ring fingers; or none of the above? (2) Which of the following muscles are weak with C8–T1 radiculopathies but intact with ulnar neuropathy at the elbow: flexor digiti minimi brevis, flexor pollicis brevis, abductor digiti minimi, abductor pollicis brevis, adductor pollicis, opponens digiti minimi, opponens pollicis, medial lumbricals, lateral lumbricals, dorsal interossei, palmar interossei? Results Fifteen of 24 surgeons (63%) correctly answered the first question—that severing the ulnar nerve results in numbness of the fifth and fourth fingers. None correctly identified all four nonulnar, C8–T1-innervated options in the second question without naming additional muscles. Conclusion The ulnar nerve provides sensation to the fourth and fifth fingers and medial border of the hand. The medial antebrachial cutaneous nerve provides sensation to the medial forearm. The ulnar nerve innervates all intrinsic hand muscles, except the abductor and flexor pollicis brevis, opponens pollicis, and lateral two lumbricals, which are innervated by C8 and T1 via the median nerve. By examining these five muscles, one can clinically differentiate cubital tunnel syndrome from C8–T1 radiculopathies. Although all participants considered themselves to be experienced cervical spine surgeons, this study reveals inadequate knowledge regarding the clinical manifestations of C8–T1 radiculopathies and cubital tunnel syndrome.