Prospective Evaluation of Reverse End to Side Anterior Interosseous Nerve to Ulnar Nerve Transfer for Severe Compressive Ulnar Neuropathy at the Elbow

Study Overview
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Brief Summary
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Ulnar nerve compression at the elbow is a common problem and can significantly affect hand function in severe cases. The current, standard treatment is Ulnar nerve decompression with or without transposition (moving the ulnar nerve to a site where there is less compression). In severe compression, the clinical results after this surgery are typically poor. Distal transfers of functioning nerves (at the level of the wrist) to the compressed ulnar nerve (anterior interosseous nerve to ulnar motor fascicles) have been suggested to supercharge or augment hand muscles while nerve axons regenerate from the level of the elbow after decompression/transposition. In fact, this treatment is becoming widely adopted without clear evidence that it changes outcomes. The investigators propose to prospectively compare the effectiveness of ulnar nerve decompression/transposition versus decompression/transposition and distal nerve transfer.

Detailed Description
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The purpose of this study is to prospectively compare the outcomes of patients with severe (intrinsic hand muscle dysfunction) compressive ulnar neuropathy at the elbow treated with ulnar nerve decompression and subcutaneous transposition alone versus ulnar nerve decompression with subcutaneous transposition and AIN to ulnar nerve reverse end-to-side transfer. The study objectives of this project are the following: 1. To prospectively compare the clinical outcomes of patients with severe ulnar neuropathy at the elbow who receive ulnar nerve decompression with subcutaneous transposition and AIN to ulnar motor reverse end-to-side nerve transfer versus decompression and subcutaneous transposition alone. 2. To prospectively compare the electrophysiologic outcomes (nerve conduction studies and EMG) of patients with severe ulnar neuropathy at the elbow who receive ulnar nerve decompression with subcutaneous transposition and AIN to ulnar motor reverse end-to-side nerve transfer versus decompression and subcutaneous transposition alone.

Official Title
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Prospective Evaluation of Reverse End to Side Anterior Interosseous Nerve to Ulnar Nerve Transfer for Severe Compressive Ulnar Neuropathy at the Elbow

Conditions
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Severe Compressive Ulnar Nerve Neuropathy (McGowan Grade III)

Intervention / Treatment
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* Procedure: Surgery:ulnar nerve transposition with AIN to ulnar nerve transfer
* Procedure: Surgery:ulnar nerve subcutaneous transposition without AIN to ulnar nerve transfer.


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult patients (greater than 18 years) with severe compressive ulnar nerve neuropathy (McGowan grade III) at the elbow who consent to either ulnar nerve decompression with transposition alone or ulnar nerve decompression with transposition plus nerve transfer. Exclusion Criteria: Patients under the age of 18 and over 70. Patients with ulnar neuropathy at multiple anatomic locations along the course of the nerve. Patients with mild to moderate ulnar neuropathy (McGowan grade I and II).

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Reverse End-to-side<br>Surgery: a reverse end-to-side AIN to ulnar nerve transfer whereby the motor branch of the ulnar is left intact and the end of the AIN nerve is coapted to the side of the ulnar motor fascicle(5,6). The advantage of this technique is it preserves the continuity of the ulnar motor branch for axons if they do eventually reinnervate the intrinsic muscles while augmenting or babysitting these muscles during the time period until this occurs. | Procedure: Surgery:ulnar nerve subcutaneous transposition without AIN to ulnar nerve transfer.<br> <br> * Other names: standard care;|
| Active Comparator: Surgery:standard care<br>Surgery: the anterior interosseous (AIN) to motor branch of the ulnar nerve transfer has been established as an effective means to reinnervate ulnar innervated intrinsic hand muscles (without loss of function from using the AIN) when nerve injury is too proximal for recovering axons to reach the hand by 18 months. . The procedure (surgery) is presently the standard of care | Procedure: Surgery:ulnar nerve transposition with AIN to ulnar nerve transfer<br> <br> * Other names: experimental;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| pain scores on the numeric pain rating scale | The patient-rated ulnar nerve evaluation (PRUNE) | one year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| evaluation of reinnvervation of hand intrinsic muscles | Electromyography (EMG) | one year | 
| functional performance assessment on the numeric scale | The patient-rated ulnar nerve evaluation (PRUNE); Michigan hand outcome questionnaire | one year |