Numbness of the little and ring fingers: Signs of ulnar nerve entrapment that should not be ignored

The case I would like to share is a female patient nearly 70 years old who presented with prolonged hand numbness. However, the distinctive feature is that the patient did not experience numbness in the fingers typically affected in carpal tunnel syndrome, but rather in the little finger and half of the ring finger.

Image 1: The patient's location of hand numbness

Upon examination, I noted muscle atrophy in the hypothenar eminence, interosseous muscles, and the adductor pollicis muscle. These are fairly typical signs of ulnar nerve injury, indicating that the compression has been ongoing for a relatively long period.

Regarding ulnar nerve lesions, there are two segments. First is the elbow segment. Second is the wrist segment. Specifically at the elbow, the ulnar nerve must pass through three narrow-risk sites including: the site piercing the intermuscular septum, the segment running in the ulnar nerve groove behind the elbow, and the segment entering the forearm. Consequently, this is a very common site for ulnar nerve entrapment syndrome.

In such cases, electromyography can help accurately determine whether the ulnar nerve is compressed at the elbow segment or the wrist segment to guide appropriate treatment.

For this patient, in addition to ulnar nerve entrapment, the patient also had a valgus deformity of the elbow. This deformity causes the ulnar nerve to be continuously stretched, worsening the numbness symptoms over time. After thoroughly discussing the condition and treatment options, the patient and I decided to proceed with surgery.

The procedure performed was ulnar nerve release at the elbow and anterior transposition of the ulnar nerve. Simply put, instead of letting the nerve continue to run behind the elbow, the nerve is moved to the front. As a result, in both flexion and extension of the elbow, the ulnar nerve remains in a more relaxed state, reducing the risk of stretching or recurrent compression.

Images 2 & 3: The surgeon performing anterior transposition of the ulnar nerve

The goal of the surgery is to help the patient reduce hand numbness, prevent progressive nerve damage, and provide favorable conditions for nerve recovery.

Images 4 & 5: Dr. Vu Anh operating on the patient

However, most patients only seek medical examination when symptoms have lasted for many months, or even years. At this point, not only is there severe hand numbness, but the hand muscles have also become noticeably atrophied and weak.

Therefore, even though surgery can completely release the compression site, the nerve still needs time to recover. This process does not happen immediately and usually takes several months. Some patients may experience earlier improvement in numbness, but for atrophied muscles to recover and muscle strength to significantly improve, it usually takes longer, sometimes over 6 months, combined with an appropriate rehabilitation program.

Therefore, I often advise everyone that if you experience prolonged hand numbness, especially at night, or begin to have signs of hand weakness and reduced grip strength, you should consult a specialist early. Early detection and treatment not only make the treatment process easier but also provide a better chance of recovery.