The Development of New Scoring System to Define the Presence of Instability and the Need of Fusion in Degenerative Lumbar Spinal Stenosis - Jakarta Instability Score.

Study design: Systematic review, expert opinion and Delphi technique, and validity and reliability studies.

Objective: We developed Jakarta Instability Score (JIS) to identify spinal instability and the need of fusion in degenerative lumbar spinal stenosis (LSS).

Methods: This study consisted of systematic review to find predictors of spinal instability, expert opinion and modified Delphi technique to develop JIS, and validity and reliability studies of the newly developed JIS.

Results: A total of 54 studies were included in the systematic reviews to obtain predictors of spinal instability. Through expert opinion and modified Delphi technique, JIS was developed and consisted of the clinical component (back pain), dynamic radiograph component (dynamic translation and angulation), and MRI component (facet joint effusion), each of the component would be scored, and the total scoring would be from 0 to 14. The final scoring would classify patients into three groups: stable group (score of 0 to 4) in which the fusion is not needed, potentially unstable group (score of 5 to 8) in which the decision of fusion is based on surgeon's clinical judgment, and unstable group (score of 9 to 14) in which the fusion is needed. Final step of study concluded that this JIS had a high validity and reliability.

Conclusion: The newly developed JIS was a valid and reliable scoring system that could help to identify the presence of instability in LSS and can be used as a guideline to decide whether spinal fusion will be needed.