Cubital Tunnel Syndrome
The ulnar nerve is one of the major nerves of the arm. It innervates the small muscles of the hand and gives sensation to the little finger and half of the ring finger.
At the elbow the ulnar nerve passes through a small space called the Cubital Tunnel, which is located between the funny bone (medial epicondyle) and the tip of the elbow (olecranon process). Entrapment of the nerve in this space is referred as Cubital Tunnel Syndrome.
This is felt as an intermittent tingling or numbness in the little finger on bending the elbow and usually occurs at night. As the condition gets worse the symptoms may be present during the day also, particularly during tasks that involve bending the elbow. As the condition progresses, the tingling may become permanent and result in weakness and/or wasting of the muscles in the hand which can result in dropping things more often.
The majority of cases occur for no particular reason (idiopathic). However some cases are related to diabetes, arthritis, trauma childhood elbow fractures elbow (Tardy Ulnar Nerve Palsy) and recent elbow surgery.
How is the diagnosis made?
The diagnosis can be made with a careful history and physical examination.
Gently tapping over the nerve in the Cubital Tunnel (Tinel’s Test) or asking the patient to keep the elbow flexed whilst applying digital pressure over the Cubital Tunnel may incite a tingling sensation or an electrical shock to the little finger. As the condition progresses, the muscles in the hand are deprived of their electrical supply causing them to weaken and then eventually waste. This is most noticable between the thumb and the index finger on the back of the hand (1st dorsal interosseous muscle) and just above the little finger.
Nerve conduction studies confirm the diagnosis and determine the severity of the problem to help your surgeon predict the likelihood of recovery with surgery. If however you have a variation of the condition, usually seen in younger patients, where the nerve flicks in and out of the Cubital Tunnel (Ulnar Nerve Subluxation) then the nerve conduction tests are usually negative. In these cases dynamic assessment with ultrasound scan can show the nerve subluxing. MRI is used occasionally to help show where exactly the nerve is being trapped and if an extrinsic factor such as a spike of bone from on old injury or osteoarthritis is responsible.
What is the treatment?
Initial treatment for mild symptoms includes activity modification and nightime extension splinting.
If however the mild symptoms do not resolve or symptoms are more severe at the outset then surgery may be indicated. This is performed as a day case under a general anaesthetic. The operation is performed through an incision on the inner aspect of the elbow. Releasing the nerve without moving it (in-situ decompression). If however if the nerve keeps flicking out of its groove (subluxing) or is under significant tension it may be necessary to move the nerve to the front of the elbow (transposition).
The outcome of surgery is generally very good but depends on the severity of symptoms at the time of surgery.
Rehabilitation is supervised by one of our team of physiotherapists. The sling is discarded at 2 weeks to encourage active movement. By 6 weeks you should be able to return to normal activity including sports. It can however take up to 6 months for symptoms to resolve. It is important to note that 3/4 of patients will still experience some symptoms even after a successful procedure. The aim of surgery is to stop the symptoms from getting worse but total recovery cannot be guaranteed.
Risks of Surgery
The risks are low but include infection, bleeding, nerve injury, scar tenderness, a patch of numbness over the inner aspect of the elbow, new pain at the elbow and worsening of symptoms.