An initial clinical experience to improve postoperative monitoring of peripheral nerve regeneration following neurotmesis using magnetic resonance imaging at 1.5 Tesla.

Background: Peripheral nerve lesions in the upper limbs occur predominantly in reproductive-age men and are often caused by sharp objects. Microsurgery is the choice treatment for these injuries, and regeneration after surgery typically is evaluated with clinical and electrophysiological examinations. The aim of this study was to use magnetic resonance imaging (MRI) to investigate peripheral nerve regeneration after complete neurotmesis, and to compare the MRI findings with those obtained with clinical and EMG evaluations.

Methods: We conducted a prospective analysis of 6 patients referred to the Neurosurgery Unit of the University Hospital of Brasília (HUB) with a diagnosis of traumatic neurotmesis of the ulnar nerve. Patients that underwent primary neurorrhaphy were followed with clinical evaluation to monitor the progression of nerve regeneration and clinical recovery, which included physical examination, electromyography (EMG) and MRI on postoperative days 14 and 50 and physical examination along with EMG after 6 months. T2 signal intensities on 1.5-T MRI were analyzed simultaneously with other clinical evaluations.

Results: We observed hyperintense T2 signals at the first postoperative examination, which decreased significantly by the second postoperative examination (P<0.05). All patients showed partial recovery of nerve function 6 months after surgery.

Conclusions: These findings corroborate those of previous studies using experimental models and at least 1.5-T MRI. The signal decrease in the repaired nerves could be correlated to the ingrowth of regenerating axons. Therefore, 1.5-T MRI might be used to diagnose discontinuities within peripheral nerves, detect neuromas, monitor nerve regeneration, and determine the prognosis after peripheral nerve repair, presenting as a non-invasive exam.