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.

Surgical method for cervical myelopathy caused by ossification of posterior longitudinal ligament depends on cervical sagittal alignment and shape of ossification mass. For K-line (-) patients, indirect decompression method such as laminoplasty may not be effective since posterior shift of spinal cord would not occur. Therefore, other surgical method is frequently needed in this patient group. In this article, we would review surgical methods that could be applied for patients with K-line (-) cervical myelopathy caused by ossification of posterior longitudinal ligament.

Cervical ossification of posterior longitudinal ligament (OPLL) can cause cord compression which can lead to myelopathy. Operative management including anterior fusion or laminoplasty is needed in these cases. Understanding the progression course of OPLL, risk factors of progression, and risk factors of myelopathy caused by OPLL is essential to determine the necessity, timing and method of operation. Therefore, we will review the previous study results regarding characteristics and progression course of OPLL. Furthermore, the results of study about risk factors and progression course of OPLL undergoing conservative management will be discussed.

Among the complex causes of chronic low back pain, suboptimal injury of ligament in the lumbosacral spine is common. Injured ligaments can become a primary pain source and raise secondary pain with referred pain pattern. Due to the low blood supply to the ligaments, ligaments are notoriously poor healer. In order to compensate the poor healing of ligament, prolotherapy has been introduced and used for more 60 years. To date, no definite recommendations have not been made based on literature available. However, if conventional treatment modalities have failed in patient with chronic back pain in lumbosacral spine, prolotherapy targeted on ligaments around lumbosacral spine should be considered in appropriate patients.