Cubital tunnel syndrome
Cubital tunnel syndrome is a common ulnar nerve neuropathy in which the nerve is entrapped at the elbow. It is the second most common peripheral nerve compression syndrome. The cubital tunnel is bordered medially by the medial epicondyle and laterally by the olecranon process and the tendinous arch joining the heads of the flexor carpi ulnaris. The roof is formed by the epicondylo-olecranon ligament. Most cases are idiopathic, although trauma such as elbow fracture or dislocation or repeated motions may cause nerve irritation. Patients with end-stage renal disease undergoing hemodialysis may also be predisposed to this syndrome, due to elbow positioning, vascular access, and underlying disease.
Initially, patients present complaining of parasthesias of the fourth and fifth digits (ring finger and little finger). Syndrome progression presents with hand weakness, specifically with loss of coordination or clumsiness of the affected fingers. Elbow pain, hand cramping, and muscle wasting may also be present. Physical exam findings include Froment’s sign (tested by holding a flat object between the thumb and index fingers, assessing weakness of the adductor pollicis), overt clawing of the fourth and fifth digits, and abduction of the little fingers (Wartenberg’s sign). Diagnosis is made on the basis of history and physical exam findings as well as neurophysiological diagnostic testing such a nerve conduction studies and EMG.
Conservative management is preferred for patients with mild symptoms. Patients who fail nonsurgical management are candidates for surgical treatment. Options include nerve decompression with or without transposition. Simple decompression is recommended in most cases, unless there is a bony deformity or nerve subluxation.
Guyon canal entrapment (ulnar tunnel syndrome)
Guyon canal entrapment is compression of the ulnar nerve at the wrist. The boundaries of Guyon’s canal consist of the superficial palmar carpal ligament superiorly, the deeper flexor retinaculum and hypothenar muscles inferiorly, the pisiform and pisohamate ligamentsmedially, and the hook of the hamate laterally. Guyon’s canal is superficial to the transverse carpal ligament, which is implicated in median nerve compression in carpal tunnel syndrome.
As the ulnar nerve divides into a superficial, sensory branch and a deep, motor branch while passing through the canal, symptoms may present in one of 3 ways:
- 1: weakness of all the intrinsic hand muscles innervated by the ulnar nerve and numbness and tingling of the fourth and fifth digits and ulnar half of the palm
- 2: weakness only
- 3: sensory deficit only
Proximal injury is more likely to produce motor symptoms with or without paresthesia, while distal injury is more likely to cause isolated sensory problems.
Symptoms may be progressive, beginning as sensory findings only and worsening to include weakness.
Unlike cubital tunnel syndrome, patients may also experience numbness and tingling of the dorsum of the hand. History and physical exam findings are usually sufficient for diagnosis although Nerve Conduction Studies and EMG are often performed to confirm diagnosis
Nonsurgical management is first-line. Surgical decompression is rare but may be considered in refractory cases. Options include simple decompression or decompression with subcutaneous transposition.
References
- Cutts, S. Cubital tunnel syndrome. Postgrad Med J. 2007; 83(975): 28-31.
- Greenberg M. Handbook of Neurosurgery. 6th ed. New York: Thieme Medical Publishers, 2005.
- Vahdatpour B, Maghroori R, Mortazavi M, Khosrawi S. Evaluation of ulnar neuropathy on hemodialysis patients. J Res Med Sci. 2012; 17(10): 905-10.