Effect of posterior instrumented fusion on three-dimensional volumetric growth of cervical ossification of the posterior longitudinal ligament: a multiple regression analysis

Publication date: Available online 8 March 2018
Source:The Spine Journal
Author(s): Jong Joo Lee, Dong Ah Shin, Seong Yi, Keung Nyun Kim, Do Heum Yoon, Hyun Chul Shin, Yoon Ha
Background Context: Despite the fact that ossification of posterior longitudinal ligament (OPLL) is a three-dimensional disease, conventional studies have mainly focused on a two-dimensional measurement, and it is difficult to accurately determine the volume of OPLL growth and analyze the factors affecting OPLL growth after posterior decompression (laminoplasty or laminectomy and fusion).Purpose: This study aimed to investigate the factors affecting OPLL volume growth using a three-dimensional measurement.Study Design/Setting: This was a retrospective case study.Patient Sample: Eighty-three patients with cervical OPLL who were diagnosed as having multilevel cervical OPLL of more than three levels on cervical computed tomography (CT) scans were retrospectively reviewed from June 1, 1998 to December 31, 2015.Outcome Measures: The OPLL volume from the C1 vertebrae to the C7 vertebrae was measured on preoperative and the most recent follow-up CT scans.Methods: Eighty-three patients were retrospectively examined for age, sex, body mass index, hypertension, diabetes, type of OPLL, surgical method, preoperative cervical curvature, and preoperative and postoperative cervical range of motion. Preoperative cervical CT and the most recent follow-up cervical CT scans were converted to digital imaging and communications in medicine data, and the OPLL volume was three-dimensionally measured using the Mimics® program (Materialise, Leuven, Belgium). The OPLL volume growth was analyzed using univariate and multivariate analyses.Results: The average follow-up period was 32.36 (±23.39) months. Patients' mean age was 54.92 (±8.21) years. In univariate analysis, younger age (p = 0.037) and laminoplasty (p = 0.012) were significantly associated with a higher mean annual growth rate of OPLL (%/year). In multivariate analysis, only laminoplasty (p = 0.027) was significantly associated with a higher mean annual growth rate of OPLL (%/year). The mean annual growth rate of OPLL was about 7 times faster with laminoplasty (8.00 ± 13.06%/year) than with laminectomy and fusion (1.16 ± 9.23%/year).Conclusions: Posterior instrumented fusion has the effect of reducing OPLL growth rate rather than motion-preserving laminoplasty. Patients' age and the surgical method need to be considered in surgically managing the multilevel OPLL.



http://ift.tt/2IdP2lP