Ossification Shape May Predict Outcomes of Laminoplasty in the Treatment of Cervical Myelopathy

31st Annual Meeting of the North American Spine Society Highlight

In patients with cervical myelopathy due to ossification of the posterior longitudinal ligament (OPLL), a hill-shaped ossification observed on sagittal image may be an important predictor of poor surgical outcomes following laminoplasty, according to systematic review presented at the 31st Annual Meeting of the North American Spine Society in Boston, MA. However, the body of high-quality evidence assessing whether characteristics of OPLL predict of outcome is limited, the investigators noted.Ligaments of the spine labeled“Unfortunately, we weren’t able to make any substantial conclusions as to the most important OPLL predictors of outcome,” said coauthor Lindsay Tetreault, PhD, who presented the data on behalf of Hiroaki Nakashima, MD. Dr. Tetreault is a postdoctoral fellow at the University Health Network in Toronto.

Findings Were Based on Eight Retrospective Cohort Studies
The researchers performed a systematic review of the literature to search for studies in English or Japanese that evaluated the association between OPLL features and surgical outcome in adult patients. Of a total of 2,318 citations identified, only 7 retrospective cohort studies were selected for inclusion as they included multivariate analysis that controlled for potential confounders.

These studies were rated as Level II (2) or Level III (5) evidence, and the main outcome measure was Japanese Orthopedic Association (JAO) score in 6 studies, and Nurick grade in 1. The overall body of evidence was assessed using the Grades of Recommendation Assessment, Development and Evaluation (GRADE) working group with recommendations from the Agency for Healthcare Research and Quality.

Hill-Shaped Ossification May Predict Worse Surgical Outcomes
A single retrospective study found that patients with a hill-shaped ossification on sagittal image have worse outcomes in terms of postoperative JOA score than those with a plateau-shaped lesion. The evidence supporting this potential predictor of outcome was rated as low, because the findings are based on a cohort study.

“In terms of the other OPLL characteristics, any that reflect severe compression, including higher occupying ratio and a lower space available for the spinal cord, or any that would increase the challenge of surgery would be predictive of worse outcomes,” Dr. Tetreault said, adding that these hypotheses can be deduced from trends in this study. 

Further prospective research is required to elucidate the relationships between surgical outcomes and various OPLL factors, the investigators concluded.

To view additional meeting highlights from the 31st Annual Meeting of NASS, click here.

Updated on: 10/26/17
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