Diagnostic and prognostic value of navigated transcranial magnetic stimulation to assess motor function in patients with acute traumatic spinal cord injury

Abstract

Introduction

Traumatic spinal cord injuries (SCI) represent a profoundly life-altering diagnosis.

Research question

The aim of this study was to evaluate the diagnostic and prognostic value of navigated transcranial magnetic stimulation (nTMS) in assessing motor function in the management of patients with acute SCI.

Material and methods

nTMS motor mapping of both upper extremities (UE) and lower extremities (LE) was performed in patients suffering from acute traumatic SCI. Data from intraoperative neuromonitoring (IONM) and patient outcomes, including American Spinal Injury Association Impairment Scale (AISA) scores, were analyzed.

Results

The patients had a mean age of 68.9 ± 15.6 years (range: 28–94 years). Preoperatively, 7 patients (35.0%) were classified as AISA A or B, and 13 (65.0%) were classified as AISA C or D. At follow-up, 5 patients (25.0%) had improved.

In all patients motor evoked potentials (MEPs) were elicited. MEPs of UE muscles were observed in 38 (61.3%) muscles in IONM and 41 (66.1%) muscles in TMS. MEPs of LE muscles were observed in 5 (19.2%) and 7 (26.9%) muscles, respectively. e

Combining the results of IONM and nTMS, a sensitivity of 0.852 and a specificity of 0.889 for motor function of the tested muscle at follow-up was achieved for upper extremity muscles. For lower extremity muscles, a sensitivity of 0.571 and a specificity of 1.00 was achieved.

Discussion and conclusion

nTMS in patients with acute SCI provides an objective assessment of motor system integrity. Despite a relatively low sensitivity, potentially due to decreased excitability, this technique exhibited excellent specificity in predicting short-term and long-term motor outcomes.