Transcranial Motor Evoked Potentials as a Predictive Modality for Postoperative Deficit in Cervical Spine Surgery – A Meta-analysis
Rajiv Reddy1, Vamsi Krishna Gorijala2, Robert Chang1, Katherine Anetakis3, Jeffery Balzer3, Donald Crammond3, Varun Shandal3, Joon Y Lee1, Jeremy Shaw1, Parthasarathy Thirumala3
1Pittsburgh Orthopedic Spine Research, 2Neurological Surgery, 3Neurological Surgery, Neurology, University of Pittsburgh Medical Center
Objective:
To evaluate whether intraoperative transcranial motor evoked potential (TcMEP) changes can predict postoperative neurologic complications in patients undergoing cervical spine surgery.
Background:
Cervical decompression and fusion surgeries are commonly performed to relieve spinal cord and nerve root impingement. Potential intraoperative injury to the spinal cord and nerve roots poses a nontrivial risk for consequent postoperative deficits. Although neuromonitoring with intraoperative TcMEPs is often used in cervical spine surgery, its therapeutic value remains controversial.
Design/Methods:
A meta-analysis of the literature using PubMed to retrieve literature on intraoperative TcMEP monitoring during cervical spine surgery, excluding aneurysms, tumors, and trauma, was performed. Data collection included study design, patient demographics, procedure type/approach/indication, modalities used, TcMEP alarm criteria, TcMEP changes (including reversible and irreversible changes), and postoperative neurological deficit. The sensitivity, specificity, and diagnostic odds ratio (DOR) of overall, reversible, and irreversible TcMEP changes for predicting postoperative neurological deficit were calculated.
Results:
Nineteen studies were included in the final analysis. The total cohort consisted of 45,367 patients, and the incidence of postoperative neurological deficits was 0.37% (168/45367). Of the total cohort, 1.36% (619/45367) had a significant intraoperative TcMEP change. The incidence of postoperative neurological deficits in patients with intraoperative TcMEP changes was 15.67% (97/619), while the incidence in those without was 0.16% (71/44677).
TcMEP changes had a sensitivity of 59%, specificity of 95%, and DOR of 26.92 for predicting neurologic deficit. Reversible and irreversible changes had sensitivities of 17% and 47%, specificities of 95% and 98%, and DORs of 3.02 and 56.29, respectively.
Conclusions:
TcMEP monitoring has high specificity but low sensitivity for predicting deficits in cervical spine surgery. Patients with postoperative deficits were 27 times more likely to have experienced intraoperative TcMEP changes than those without deficits, with irreversible changes indicating a higher risk of injury than reversible changes.