Nerve Transfers for High Ulnar Nerve Palsy

Background

If the ulnar nerve is transected at the upper arm level and the likelihood of nerve recovery is low, then multiple nerve transfers can be helpful in restoring hand function.

Causes

Trauma and cancer are the most common causes of a high ulnar nerve palsy/injury. Less commonly, it can also be seen as an iatrogenic complication during another surgical procedure, such as lipoma removal, placement or removal of implanted contraceptive devices, cubital tunnel release, and others.

Symptoms

Depending on the severity of the ulnar nerve involvement, there can be numbness, tingling, weakness in the affected hand. Muscles can atrophy, giving rise to what is called an “ulnar claw hand” which has a characteristic appearance.

Diagnosis

The physical examination is most important to identify the extent of sensory and motor involvement and help localize the site of the ulnar nerve lesion. Ultrasound and MRI are additional diagnostic modalities that help characterize the anatomy in greater detail. Neurophysiologic testing is an invaluable tool to help identify and characterize the location and extent of the nerve lesion, and is a good tool for longitudinal followup to monitor the recovery. Typically this is obtained immediately after the lesion, and in 3 month intervals after that.

Treatment

With any nerve lesion, there is some urgency to treatment since the nerve regenerative potential diminishes with time, especially in high grade injuries that are operative. Reconstruction can range from nerve decompression, to transposition, primary repair, and reconstruction with nerve graft. Another technique is using so-called nerve transfers that allow the surgeon to sacrifice non-critical or redundant portions of nearby nerves to restore motor, and also sensory function to the ulnar nerve.

This example shows a middle aged patient with a recurrence of a chondrosarcoma at the shoulder/upper arm level. His ulnar nerve had to be sacrificed over a significant length of at least 10 cm. Considering this significant nerve gap, we elected to forego a nerve reconstruction and to proceed with nerve transfers at the wrist and forearm level. In addition, the patient had undergone radiation which reduced the likelihood of a successful nerve reconstruction at the upper arm level.

This shows the incision that was performed. Interestingly, this fairly limited incision provides a tremendous exposure to the forearm structures, allowing for all the nerve transfers to be performed through this single incision.

The two following images show the nerve and tendon transfers that were performed, including:

• deep flexor tendon side-to-side tenodesis
• AIN to motor ulnar nerve transfer (end-to-end)
• dorsal branch of ulnar nerve to palmar cutaneous nerve transfer
• 3rd webspace sensory nerve to ulnar sensory nerve (end-to-end)
• distal 3rd webspace common digital nerve transfer to median nerve (end-to-side)

At two years postoperatively, the patient has regained protective sensation in the ulnar nerve distribution. No clawing is noted. Ulnar intrinsics have recovered ⅘ strength. Most importantly, he remains tumor free.