Retrospective study concerning isolated motor ulnar nerve compression at the wrist: diagnosis and prognosis, in 20 patients.
P.Croutzet, C. de Cheveigné
ASSH annual meeting 2013
There are many types of ulnar nerve compression, among them, the « motor only » compression in the hand is one of the least well known.
Considering difficulty and delay in recognizing the condition, we studied the diagnostic criteria (age, clinical signs, electromyography benefits) and the efficiency of the surgical treatment.
We reviewed all the patients operated for isolated motor ulnar compression in the hand over 22 years (n=20).
Patients included in this retrospective study were selected on different criteria : - motor ulnar nerve palsy of the first interosseous muscle always had to be present - associated ulnar nerve palsy at the wrist and at the elbow were excluded - ulnar nerve palsy with sensitive symptoms were excluded - secondar etiology of compression were excluded (wound, tumor,bicycling).
Analysis criteria were age, gender, time before surgery, importance of the motor palsy (ulnar claw, segmentar strength scale (1/5) of the first interosseous muscle and hypothenar muscles), associated pathology (diabetes, smoking, carpal tunnel syndrome), electromyographic signs. Clinical results were evaluated with different criteria: satisfaction, pain, time and quality of strength recovery, grasp strength.
There were 6 females, 14 males. The mean age was 52. Time before surgery was 8 months (5-18). Among the 20 patients, none had bilateral symptoms, 2 had an associated carpal tunnel syndrome, 14 had no motor deficit of the hypothenar muscles. 5 patients only had positive signs on elctromyography, it was only found afterwhen they presented hypothenar deficit.
Mean follow-up was 6 years. 17 patients were very satisfied, 16 patients recovered full strength in the first interosseous muscle, 3 had only partial recovery and 1 no recovery. Mean time for recovery was 7 months (3-15).
In our study, the majority of patients didn’t have a hypothenar muscle deficit. Electromyography was prescribed by the general practitioner and was only positive when the hypothenar muscles were already impaired.
Diagnosis delay was always superior to 5 months, 16 patients (16/20) had a full recovery nevertheless. However, the diagnostic delay was the only negative factor. Indeed, poor to bad results were found in patients with a diagnostic delay over one year.
In our study, clinical examination was more efficient than electromyography to diagnose isolated motor ulnar nerve compression at the wrist.
The recovery score was mainly excellent (16/20) but a diagnosis delay superior to one year was a negative prognosis factor