Treatment for Ulnar Neuropathy at the Elbow (UNETREAT)

The purpose of the study is to investigate utility and appropriateness of treatment interventions taking into account the presumed mechanisms of two main varieties of ulnar neuropathy at the elbow (UNE). The investigators hypothesize that in patients with UNE under the humeroulnar aponeurosis (HUA) surgical HUA release (simple decompression) is superior to conservative treatment. By contrast, in patients with UNE at the retroepicondylar (RTC) groove surgical HUA release (simple decompression) should not be superior to conservative treatment.

Ulnar neuropathy at the elbow (UNE) is the second most common focal neuropathy with annual incidence rate of 21 per 100.000. Therefore, in Slovenia UNE each year affects approximately 420 and in Europe 156.000 patients. In previous publications evidence was presented that idiopathic UNE consists of two conditions occurring 2-5 cm apart. In the first condition, affecting about 15% of UNE patients, the ulnar nerve is entrapped 2-3 cm distal to the medial epicondyle (ME) under the humeroulnar aponeurosis (HUA), i.e., in the cubital tunnel. In the second condition, affecting the majority (about 85%) of patients, the lesion is located at the ME or up to 4 cm proximally in the retroepicondylar (RTC) groove. As no anatomical structure constricting the ulnar nerve is usually found in that segment, the most probable cause of UNE at this location is extrinsic ulnar nerve compression against the underlying bone. The investigators believe that these two groups of UNE patients need different therapeutic approaches: (1) surgical release for ulnar nerve entrapment distal to ME and (2) conservative treatment for extrinsic nerve compression in the RTC groove. The efficiency of this therapeutic approach was already evaluated and significant clinical improvement was found in 80% of UNE patients. However, the design of that study did not enable to obtain an indisputable evidence that outcome was a result of treatment approach. It is still possible that improvement observed in patient population was a consequence of natural history rather than therapy. To resolve this problem a properly designed randomized control trial is needed. The investigators believe such trial would prevent numerous unnecessary and delayed operations in UNE patients.

Ulnar neuropathy at the elbow, Electromyography, Ultrasonography, Treatment, Surgery, Conservative treatment

Patients with suspected UNE will be prospectively recruited in a single secondary referral center. First of three blinded examiners will obtain patients' history and perform focused neurological examination. The second examiner will perform electrodiagnostic (EDx) and the third ultrasonographic (US) studies. Patients with UNE under the HUA and in the RTC groove will be randomly distributed in two groups for surgical HUA release and conservative treatment. During surgical intervention the surgeon will cut the HUA with minimal incision technique. All patients (including surgically treated) will be given pictured recommendations with descriptions, which limb positions should be avoided. In order to prevent deterioration in conservatively treated group of patients with UNE at HUA, control neurological examination will be performed every 3 months. At 1 year follow-up we will use identical protocol as at the time of initial diagnostic evaluation.

Three examiners will perform one part of diagnostic evaluation that will include: (1) patients' history and focused neurological examination, (2) (EDx) and (3) US studies. They will be blinded to the findings of the other parts of the evaluation.

Patients with UNE under the HUA randomly distributed for simple decompression of the ulnar nerve. Patients will also receive pictured recommendations with descriptions, which limb positions should be avoided. Control neurological examination will be performed every 3 months and identical protocol as at the time of diagnostic evaluation at 1 year follow-up.

Patients with UNE under the HUA randomly distributed for conservative treatment. Patients will receive pictured recommendations with descriptions, which limb positions should be avoided. In order to prevent deterioration in conservatively treated group of patients with UNE at HUA control neurological examination will be performed every 3 months. Criteria for surgical HUA release will be clinical deterioration or lack of clinical improvement after 12 months. Prior to surgical HUA release and at 1 year follow-up identical protocol as at the time of diagnostic evaluation will be performed.

Patients with UNE in the RTC groove randomly distributed for simple decompression of the ulnar nerve. Patients will also receive pictured recommendations with descriptions, which limb positions should be avoided. At 1 year follow-up identical protocol as at the time of diagnostic evaluation will be performed.

Patients with UNE in the RTC groove randomly distributed for conservative treatment. Patients will receive pictured recommendations with descriptions, which limb positions should be avoided. At 1 year follow-up identical protocol as at the time of diagnostic evaluation will be performed.

Patients will be given pictured recommendations with descriptions, which limb positions should be avoided.

Primary outcome of the study will be percentage of patients with at least moderate symptoms improvement or complete remission

Percentage of patients with near normal (4+/5 on MRC) or normal (5/5 on MRC) ulnar hand muscles strength

Improvement in strength of the first dorsal interosseous (FDI) muscle as measured by dynamometer (microFET2)

Inclusion Criteria: continuous numbness or paresthesias in the 5th finger, weakness of the ulnar-innervated muscles or hand clumsiness. Exclusion Criteria: previous elbow fracture or surgery, polyneuropathy, symptoms of polyneuropathy, conditions causing polyneuropathy (e.g., diabetes) or multiple mononeuropathy, motor neuron disorders (e.g., monomelic amyotrophy, amyotrophic lateral sclerosis - ALS).

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