What is cubital tunnel syndrome?
The ulnar nerve passes from the posterior compartment of the arm to the anterior compartment just proximal to the medial epicondyle of the humerus (“funny bone”). The nerve goes through the cubital tunnel beginning at the medial epicondyle and courses between the two heads of the flexor carpi ulnaris (FCU) beneath the aponeurosis (thick fascial band). The nerve supplies function to the FCU, FDP to L and R, hypothenar, interosseous, adductor pollicis, deep head of the flexor pollicis brevis, and lumbrical muscles to the L and R. The ulnar nerves gives sensation to the L and 1/2 R and the dorso-ulnar aspect of the hand. It is within this tight space or tunnel that the nerve is susceptible to trauma.
What causes cubital tunnel syndrome?
- Compressive forces: fibrous bands, anomalous muscles, tumors
- Traction or stretching of the nerve following trauma
- Friction from repetitive elbow flexion; elbow flexion decreases the space within the cubital tunnel
What are the symptoms of cubital tunnel syndrome?
- Pain of an aching nature at the medial elbow radiating into the medial forearm
- Numbness and paresthesias to the L,1/2R
- Elbow flexion aggravates symptoms
- Awakens at night
- Weakness of grip or dexterity
How to diagnose cubital tunnel syndrome
In addition to a careful history of the symptoms as described above,an examination will reveal:
- Tinel’s test (thumping skin over point of nerve irritation produces shocks or tingling in nerve distribution)
- Elbow flexion test (flexion of the elbow maximally with the wrist extended puts the irritable nerve under stretch reproducing symptoms within 30 seconds
- Sensation diminished to the L,1/2R and dorso-ulnar hand
- Muscle weakness and atrophy
Additional tests may be helpful:
- X-rays of elbow with cubital tunnel view to assess the bones and joint
- Electrodiagnostic testing: slowing across the elbow localizes the problem; can assess the severity of the condition; a normal test does not rule out this problem as ~20-40% of patients in my experience with surgical lesions have a negative test
Non-surgical treatment of cubital tunnel syndrome:
Avoid direct pressure on nerve; limit full elbow flexion; splint/elbow pads; work modification by limiting repetitive elbow flexion; NSAID (i.e. Advil); may be effective in patients that have mild, intermittent symptoms.
Surgical treatment of cubital tunnel syndrome:
If symptoms are constant or weakness develops or conservative care has failed, then surgery is indicated. There are three acceptable procedures: nerve decompression and medial epicondylectomy, and anterior transposition with subcutaneous or submuscular placement. The medial epicondylectomy procedure is preferable as the nerve is left in its normal position as opposed to the transposition procedures which move the nerve, potentially disturbing part of its blood supply. However, in overhead elite athletes the submuscular positioning is preferable.
The patient is placed in a long arm splint until returning 8-10 days later for suture removal at which time the splint is discontinued and therapy begins in the medial epicondylectomy. In the anterior transposition procedures a splint is worn for 3 weeks. The length of therapy depends on the severity of the condition.
How can Dr. Knight help you with cubital tunnel syndrome?
Dr. Knight has years of significant experience in peripheral nerve surgery such as cubital tunnel syndrome. While cubital tunnel syndrome is usually resolved with non-operative treatment, if surgery becomes necessary, Dr. Knight will carefully determine with your help what your daily activities are and what sports you enjoy to determine which minimally invasive procedure is best to return you to painfree activities quickly.
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