Abstract
Objective: In this study, we outline the relationship between a selected surgical approach (anterior or posterior approach) as it relates to localization of a spinal cord lesion (anterior or posterior spinal pathways) assessed by evoked potentials (SEP, MEP) and the impact of this approach on postoperative condition of patients with cervical spondylotic myelopathy. Methodology: 65 patients with clinical signs of cervical myelopathy were included in the study.
These patients had been indicated for surgery that wassubsequently performed using either the anterior (a) or posterior (p) approach. The patients were assessed using Nurick and mJOA scores before surgery, then at 12 months, and finally 24 months after the surgery.
In addition, they were preoperatively examined with a battery of evoked potentials (EP) – somatosensory evoked potential (SEP) and motor evoked potential (MEP) tests. Based on EP, principal spinal cord disability was determined: A – anterior (maximum changes in MEP), P – posterior (maximum changes in SEP).
On the basis of EP partitioning and the surgical approach used, the group was divided into four subgroups: Aa, Ap, Pa, Pp. Results: Objective postoperative improvement mJOA score was found in all four groups.
Statistically significant improvement was, however, detected only in the anterior approach groups regardless of primacy of SEP or MEP lesion (Aa: p = 0.011, Ap: p = 0.005). Overall mJOA improvement was observed in 65% patients in this study, the remaining 35% were without any change.
Conclusion: Anterior approach led to objectively significant postoperative improvements, regardless of whether the dominant spinal cord pathology, determined preoperatively by EP, was located ventrally or dorsally. As a result of this study, there seems to be no benefit in selecting the surgical approach based on localization of dominant spinal cord pathology, as assesses by EP.