This single-cohort, prospective case series is designed to evaluate and characterize the use of Axoguard HA+ Nerve Protector™ to protect the ulnar nerve in a first revision cubital tunnel decompression procedure. Data on the primary cubital tunnel syndrome decompression, first revision decompression utilizing Axoguard HA+ Nerve Protector, participant-reported pain, motor and sensory functional outcomes, quality of life (QoL) outcomes, and recurrence/revision will be collected. This case series will help to establish the ability of Axoguard HA+ Nerve Protector to provide clinical benefits for patients undergoing a first revision cubital tunnel decompression procedure.

The objectives of this study are:

1. To evaluate the use and characterize the performance of Axoguard HA+ Nerve Protector to protect the ulnar nerve in a first revision cubital tunnel decompression by understanding post-operative outcomes (pain level, QoL, PROMs, and ulnar nerve specific functional outcomes) compared to baseline (pre-revision operative levels).
2. To summarize the safety of Axoguard HA+ Nerve Protector, an FDA-cleared device, in first revision cubital tunnel decompression procedures.
3. To characterize the feasibility of Axoguard HA+ Nerve Protector to prevent the recurrence of compressive neuropathy of the ulnar nerve at the elbow and resulting need for future revision procedures.
4. To characterize the feasibility of imaging the ulnar nerve pre- and post-operatively to assess nerve and tissue bed health.

The study population includes participants 18 years of age or older presenting for evaluation of surgery for compressive ulnar nerve neuropathy at the elbow following a primary cubital tunnel syndrome decompression.

Data will be collected from available medical records and patient reported outcomes questionnaires using approved data collection forms (paper or electronic). The following data will be collected at the respective study visits: demographics, primary decompression details, revision decompression details, baseline assessments, health-related QoL questionnaires, functional assessments, and recovery assessments.

There will be a total of nine (9) study visits (Pre-op Screening/Baseline and Operative Day visits plus seven (7) study follow-up events).

Inclusion Criteria:

1. Be ≥ 18 years of age;

2. Have symptoms of ulnar nerve neuropathy near the elbow present at 180 days or greater following a primary cubital tunnel decompression procedure.

3. Be eligible for surgical intervention;

4. Have a preoperative diagnostic such as a nerve conduction study, electromyography, or ultrasound evaluation documenting ulnar neuropathy at the elbow;

5. Have a baseline pain visual analogue scale (VAS) score due to ulnar nerve neuropathy of no less than 40/100 mm for the affected elbow;

6. Have at least one of the following:

   • Paresthesia or numbness in the ulnar nerve distribution;
   • Weakness or wasting of the small muscles of the hand (full hand muscle wasting is excluded);
   • A positive elbow flexion provocation test.

7. Undergo a first revision cubital tunnel decompression surgery with placement of Axoguard HA+ Nerve Protector circumferentially around the section of ulnar nerve affected by neuropathy;

8. Be willing and able to comply with all aspects of the treatment and evaluation schedule over 18 months; and

9. Sign and date an Institutional Review Board (IRB)/Independent Ethics Committee (IEC)-approved written informed consent prior to initiation of any study procedures.

Exclusion Criteria:

1. Have had a previous revision cubital tunnel decompression procedure;

2. Have documented evidence of concomitant neuropathic conditions affecting the subject arm or any proximal condition affecting the subject arm including, but not limited to:

   • Previously treated carpal tunnel syndrome with unresolved symptoms or current carpal tunnel syndrome that will not be treated concurrently with the revision cubital tunnel;
   • Cervical or brachial plexus abnormalities or injuries;
   • Cervical spine or shoulder disease;
   • Thoracic outlet syndrome;
   • Complex regional pain syndrome;
   • Polyneuropathy, systemic neuropathy or Lyme disease related neuropathy;
   • Previous or current surgery of the ulnar nerve at the wrist (Guyon's canal release)
   • Ulnar nerve compression at the wrist/Guyon's canal;

3. Have current trauma or past trauma with ongoing pathology that interferes with evaluation or treatment of the ulnar nerve to either side shoulder or upper extremity;

4. Have previous radiofrequency ablation, presence of nerve stimulator or received nerve implant(s) in the subject arm or be receiving an implant(s) other than Axoguard HA+ Nerve Protector during the study surgical procedure, that will impact the ulnar nerve or planned study evaluations;

5. Have a condition(s) that could confound assessments or health-related quality of life including, but not limited to:

   • Rheumatoid arthritis
   • Fibromyalgia
   • Connective tissue disorder
   • Wrist tenosynovitis

6. Be a smoker or tobacco user;

7. Currently have or have a history of alcohol or drug abuse;

8. Have uncontrolled Diabetes Mellitus at the discretion of the treating surgeon or have diabetic neuropathy in the upper extremities;

9. Have documented poorly controlled hyperthyroidism or hypothyroidism;

10. Have a known sensitivity to porcine derived materials or those containing hyaluronate or alginate or their components;

11. Be currently taking or likely to need medication(s) that may cause or contribute to peripheral neuropathy or peripheral nerve dysfunction at the discretion of the treating surgeon;

12. Be taking prescribed medication(s) including, but not limited to, narcotics 2 or more times per week for the treatment of chronic pain or chronic nerve related symptoms NOT associated with the subject ulnar nerve neuropathy; or

13. Be deemed unsuitable for inclusion in the study at the discretion of the investigator.