Ulnar Nerve Entrapment
Ulnar nerve entrapment is a medical condition consequent to the compression of the ulnar nerve along its course. Although compression may occur in the axilla and upper arm, at the elbow, the forearm and the wrist, by far the most common site of entrapment is the elbow. Ulnar nerve entrapment at the elbow is also known as cubital tunnel syndrome, the cubital tunnel being the passageway where the nerve runs at the elbow. This picture helps you to visualize the course of the ulnar nerve and its territory of innervation.
Due to specific anatomical reasons (e.g. the fascia overlying the ulnar nerve can be thicker than normally), rheumatic diseases that change the bone structures, bone deformities that are consequent to previous elbow traumas, the passageway can become narrower and therefore a compression on the ulnar nerve can result.
In 15-20% of people, flexing the elbow systematically results in “subluxation” of the ulnar nerve on the medial epicondyle (the nerve rolls out of the cubital groove just over the tip of the medial epicondyle or even completely anteriorly to it, as shown in picture B) and this can also cause the onset of symptoms.
Some life habits may also predispose to developing this syndrome (e.g. sleeping with flexed arms or spending long hours with your flexed elbow on the desk when working). This is why some professional categories (e.g. musicians such as violinists, flutists, baseball batters, pitchers and javelin throwers among athletes) are particularly exposed to it.
Ulnar nerve entrapment at the elbow is mostly affecting just one side but some patients may present it both elbows: in the latter case, symptoms may present with prevalence on one of them (most often the dominant side). The course of the syndrome is usually characterized by 3 phases.
The initial phase is associated with pain and numbness on the forearm and the hand, usually experienced as worsening at night, often completely disrupting the quality of sleep of the patient.
Initially these symptoms usually present a relapsing- remitting course but as time goes, they become continuous and their intensity worsens.
During the final stage, the persistent compression results into functional damage to the nerve: the patient develops sensory loss in the ulnar territory and muscle waste as shown in the following photo.
Muscle atrophy causes progressive decrease of strength, especially the pinch grip is impaired.
Cubital Tunnel Syndrome is diagnosed according to clinical evaluation (that means that your history is suggesting that this is what can explain your symptoms) and ruling out the possibility of other pathologies (such as cervical spine pathology). An EMG and nerve conduction study and a dynamic ultrasound of the elbow (to evaluate if there is a tendency to subluxation of the ulnar nerve during elbow flexion) are routinely utilized to confirm the clinical suspicion.
If your surgeon suspects the association with other pathologies (e.g. cervical spine pathology), further instrumental investigations can be required to complete the diagnostic assessment. However, the information provided by the investigations must always be evaluated by your surgeon before the diagnosis is confirmed.
- Conservative Treatment
Conservative treatment can be wearing splints, taking medications such as vitamin supplements. They usually provide only temporary relief. Conservative treatment is not an option when a functional damage of the nerve has been detected.
- Surgical Treatment
As the symptomatology is the consequence of mechanical compression, surgery (that is decompression of the nerve) is certainly the elective treatment option.
Cubital Tunnel Surgery
Indications for surgery: your surgeon advocates surgery after evaluation of your medical history, neurological examination and after you have completed your instrumental investigations. If muscle atrophy and sensory loss are already evident, surgery is the only treatment option and it should be performed as soon as possible to prevent further progression of the nerve damage.
Type of surgery: The procedure is performed under general anesthesia: through an incision on the elbow, the surgeon will identify the ulnar nerve above the elbow and follow its course inside the cubital tunnel. The overlying tissue is cut to relieve the compression on the nerve. In order to prevent the tendency to subluxation, the surgeon may decide to mobilize the nerve out of the cubital groove and relocate it under the skin.
After the procedure, you can resume your daily activities except performing efforts (such as carrying weights) with the operated arm.