Abstract

Purpose
This study was conducted to identify risk factors predicting the loss of cervical lordosis (LCL) in patients with multilevel ossification of the posterior longitudinal ligament (OPLL) following laminoplasty. Material and Methods: We conducted a retrospective analysis of data from patients who underwent laminoplasty at Chonnam National University Hospital between January 2013 and December 2022. Various radiological parameters and clinical outcome measures were collected perioperatively. Patients were divided into 2 groups according to the severity of LCL. We examined preoperative radiological parameters associated with LCL.
Results
We analyzed data from 109 patients (92 men and 17 women; mean age, 60.31±10.80 years). A higher T1 slope (odds ratio [OR], 1.420; p<0.001) and a lower extension ratio (OR, 0.883; p=0.019) were associated with a higher risk of LCL. T1 slope was shown to be an excellent predictor of LCL, with a cut-off value of 28° (p<0.001, area under the curve=0.918). Also, The T1 slope and extension ratio were statistically significant correlated with clinical outcomes.
Conclusions
T1 slope and extension ratio were significantly associated with LCL in patients with multilevel OPLL following laminoplasty. The cut-off value for the T1 slope was 28°, and the cut-off value for the extension ratio was 33. Therefore, in multilevel OPLL patients with a T1 slope exceeding 28° or an extension ratio below 33, a warning regarding the potential LCL should be given before performing cervical laminoplasty.

• Keywords: Cervical vertebrae, Ossification of posterior longitudinal ligament, Laminoplasty, Spinal curvatures, Kyphosis, Patient-reported outcome measures