The management of failed cubital tunnel decompression

Key points

• Cubital tunnel decompression fails much more often than carpal tunnel release; failure means persistent, recurrent or new symptoms after surgery.
• Clinically, failure can be defined as symptoms persisting three months after surgery or recurring within six months.
• Causes include incomplete decompression (up to 20% of failed cases), perineural scar, new compression points after transposition, nerve subluxation and injury to the medial antebrachial cutaneous nerve.
• The authors' preferred revision is circumferential neurolysis with medial epicondylectomy.
• Nerve wrapping and supercharging end-to-side (SETS) nerve transfer show promise but have limited evidence and remain controversial.

Overview

Failed cubital tunnel surgery is managed by finding out why it failed and, in the authors' experience, by revision circumferential neurolysis of the ulnar nerve with medial epicondylectomy. This review in EFORT Open Reviews offers a management guide based on the authors' clinical experience; they note that research on the subject is of limited quality and that there is no consensus on diagnostic criteria, classification or outcome assessment.

Why surgery fails

Persistent symptoms may reflect incomplete decompression, an unaddressed nerve subluxation, severe compression in which surgery mainly prevents deterioration, or another diagnosis such as Guyon's canal compression, thoracic outlet syndrome or lower cervical radiculopathy. Recurrent symptoms after an interval of improvement are often caused by perineural scar that impairs nerve glide, or by new compression points created at transposition. New symptoms may come from an unrecognised unstable nerve that subluxes painfully or from a painful neuroma of the medial antebrachial cutaneous nerve. Reported failure rates of primary surgery range from 2.4% to 17%, and an estimated 25% of cases have recurrent symptoms; risk factors include younger age, greater static two-point discrimination and diabetes.

Assessment

A detailed history covers the timing and severity of symptoms and any improvement after surgery, and alternative diagnoses are excluded. Examination includes the one-minute elbow flexion test, palpation for subluxation, Tinel's sign along the nerve, resisted small finger flexion, Froment's test and inspection of the scar for a cutaneous neuroma. Previous records and neurophysiology are reviewed; the authors do not routinely use imaging unless an intrinsic nerve tumour is suspected.

Revision surgery

Surgery is done under general anaesthesia or a regional brachial plexus block with an additional proximal fascial block. The previous incision is extended into unscarred tissue and a circumferential neurolysis is completed along the whole course of the ulnar nerve across the elbow. Because transposition can create new compression points, the authors prefer in situ decompression with medial epicondylectomy, which eliminates strain and the risk of subluxation; a nerve wrap is added if the nerve is heavily scarred, and cutaneous neuromas are resected and relocated proximally. No cast is needed; dressings are reduced after five days, gentle movement begins, and heavy lifting is avoided for six weeks.

Outcomes and adjuncts

Revision results are generally worse than after primary surgery: one cited study found improvement in McGowan grade in 25% of revisions compared with 64% of primary procedures. In severe intrinsic wasting, a SETS transfer from the anterior interosseous nerve to the ulnar motor fascicles may help; the largest cohort reported intrinsic strength of MRC grade 3 or higher in 33 of 42 patients. Outcome reporting is inconsistent: 101 studies used 45 unique outcomes, and the validated PRUNE score appeared in only 3% of them.

Frequently asked questions

How is failed cubital tunnel surgery defined?

Clinically, as symptoms persisting three months after surgery or recurring within six months, with or without new symptoms.

Why do the authors avoid transposition in revision cases?

In their experience it can create new compression points and distort the nerve, causing scar tether and movement-related pain.

Is this a formal guideline?

No. It is a review offering a management guide based on the authors' clinical experience; high-quality evidence on revision surgery is limited.

Source

Burahee AS, Sanders AD, Power DM. The management of failed cubital tunnel decompression. EFORT Open Rev 2021;6(9):735-742. DOI: 10.1302/2058-5241.6.200135. Open access under CC BY-NC 4.0. Summary prepared by Medpresso from the original publication; it is not a substitute for the full text or for medical advice.