[Expansive open-door laminoplasty combined with unilateral lateral mass screw in the treatment of ossification of posterior longitudinal ligament with cervical instability].

Objective: To investigate the effect of expansive open-door laminoplasty combined with single lateral mass screw fixation on the posterior longitudinal ligament ossification and cervical instability and its effect on sagittal balance.

Methods: A retrospective analysis of 65 patients with the posterior longitudinal ligament with cervical instability from May 2012 to July 2018 was conducted. The patients were divided into two groups according to the surgical method. Thirty-four patients were treated with open-door laminoplasty including 19 males and 15 females, aged 49 to 60 years old with an average age of (54.4±4.77) years old;symptoms lasted 8 to 39 months with an average of (21.0±8.2) months. Thirty-one patients were treated with single-door laminoplasty combined with single mass screw fixation including 17 males and 14 females, aged 50 to 59 years old with an average age of (55.4±3.2) years;symptoms lasted 7 to 48 months with an average of (23.7±13.1) months. General information of the two groups, including operation time, intraoperative blood loss, and postoperative complications was recorded. Sagittal vertical axis(SVA), C-C and C-C cobb angle were measured by X-ray before operation and at the last follow-up. Clinical efficacy was evaluated using the Japanese Orthopaedic Association(JOA) score.

Results: Surgery was successful in all patients. The operation time (109±15) min in the single-door laminoplasty combined with lateral mass screw fixation group was longer than that in the single-door group(128±16) min(<0.05). There was no significant difference in intraoperative blood loss, postoperative axial symptoms and follow-up time between two groups(>0.05). At the latest follow-up, both groups showed significant improvement in the motor and sensory components of the JOA score and the total JOA score compared to pre-surgery(<0.05) and no significant change in bladder function score(>0.05). There was no significant difference between two groups(>0.05). At the latest follow-up, the C-C Cobb angle increased in both groups compared to preoperative and more the single-door laminoplasty group(<0.05). The angle of the C-C Cobb angle decreased in both groups, and the reduction was greater in the single-door laminoplasty combined with lateral mass screw fixation group(<0.05). There was a significant increase in C-C SVA in the single-door laminoplasty group(<0.05) and no significant change the single-door laminoplasty combined with lateral screw fixation group(>0.05).

Conclusion: Posterior cervical laminoplasty with unilateral lateral mass screw fixation combined with single-door vertebral plate shaping surgery improves the neurological function and quality of life in patients with cervical spondylotic myelopathy complicated by ossification of the posterior longitudinal ligament and cervical instability. Compared with single-door vertebral plate shaping surgery, postoperative cervical lordosis and forward-tilt can be improved.