Is Cervical Sagittal Balance Related to the Progression of Patients with Cervical Spondylotic Myelopathy?

Abstract

To examine the preoperative patients with cervical spondylotic myelopathy (CSM): (1) whether cervical sagittal parameters are related to the progress of patients with CSM, and (2) whether cervical sagittal parameters can predict disease progression or prognosis in patients with CSM. From 2015 to 2018, 126 preoperative patients with CSM were enrolled. The inclusion criteria included cervical lateral radiograph, flexion (F), extension (E), and some clinical function scores (visual analog score, modified Japanese Orthopedic Association, Neck Disability Index [NDI], the Medical Outcomes Study 36-Item Short-Form Health Survey, Patient Health Questionnaire-9). Health Transition was used to evaluate the patient's disease progress. The following radiographic parameters were measured: (1) C0-C2 lordosis, (2) C2-C7 lordosis, (3) C7 slope, (4) T1 slope, (5) C2-C7 sagittal vertical axis, (6) cervical tilt, (7) cranial tilt, (8) cervical curvature index (CCI), and (9) CCI change constant (CCI-CC). Of the 126 patients, 101 chose surgical treatment. We followed up for 1 year and grouped the patients with the C2-C7 Cobb angle (F) > 29°. We compared the prognosis of the surgical group and the disease progression of the nonsurgical group. In preoperative patients with CSM, modified Japanese Orthopedic Association was positively correlated with cervical tilt (E), cervical tilt (range of motion), and CCI (range of motion). The larger CCI-CC is the only independent risk factor for the NDI increase. High C2-7F, low cervical tilt, and low cervical tilt (F) values are independent predictors of high Health Transition scores. Whether in the surgical group or the nonsurgical group, the recovery of patients with C2-7F > 29° was better than that of patients with C2-7F ≤ 29°. In preoperative patients with CSM, the larger CCI-CC is the only independent risk factor for the NDI increase. When the patient has a C2-C7 Cobb angle (F) > 29°, the patient's condition progresses slowly.