The study will be a non-blinded two cohort design consisting only of symptomatic patients with CuTS or compressive peroneal neuropathy or in need of peroneal nerve decompression. The first cohort will be - patients with CuTS. Evaluation of each CuTS patient will include assessment by the treating surgeon and a certified hand therapist. Patients who have clinical examination and history consistent with a diagnosis of CuTS based on subjective and functional assessment outlined below will be consented to this study. The second cohort will be patients in need PND for compressive neuropathy of peroneal nerve. PND patients will be evaluated by clinical exam and have imaging with high resolution ultrasound or MRI negative for mass lesion.

Visit 1

• Exam and discussion with surgeon
• Exam and testing with Occupational Hand Therapist (Standard of Care) as described above. (CuTS cohort)
• Diagnostic studies (EMG/NCT) (Standard of Care)
• Questionnaires - PROMIS and ODI

Visit 2

• Standard of Care surgery
• During surgery, the surgeon will perform an MMG immediately pre-decompression and immediately post-decompression of the nerve. This will entail placing a sensor and probe on the nerve that will be decompressed.

Visit 3 and 4 (6 week and 3 month post-op)

• Clinical Exam by Surgeon
• Exam and testing with Occupational Therapist (Standard of Care) as described above. (CuTS cohort)
• Questionnaires - PROMIS and ODI

Visit 5 (6 months post-op)

• Clinical Exam by Surgeon
• Exam and testing with Occupational Therapist (Standard of Care) as described above. (CuTS cohort)
• Questionnaires - PROMIS and ODI
• Evaluation of MMG parameters

Inclusion Criteria:

• Patients who have a diagnosis of Cubital Tunnel Syndrome or Compressive Peroneal Nerve Neuropathy and will be undergoing a decompressive surgery.

Exclusion Criteria:

• Patients under 18 years of age
• Patients who are unable to return for follow-up evaluation.

Subjects will be recruited in the investigator's patient population.