This meta-analysis of 19 retrospective studies (2,896 patients) quantifies the incidence of radiographic adjacent segment degeneration (ASD) after posterior lumbar fusion. It systematically evaluates which demographic, surgical, and sagittal alignment factors independently drive that risk. The goal is to give spine surgeons a prioritized, evidence-based checklist of modifiable and non-modifiable ASD risk factors.
The choice of PLIF vs. TLIF and whether to fuse to S1 have long been debated as potential drivers of adjacent segment disease. This meta-analysis clarifies that neither technique choice nor graft type meaningfully changes ASD risk — attention should shift to what actually matters.
The most actionable finding: protect the superior facet of the adjacent level at all costs. An OR of nearly 30 means a violated facet joint makes ASD almost inevitable. Use fluoroscopy or navigation to confirm screw trajectory, and be deliberate with retractor placement at the cranial end of your construct.
For pre-operative planning, screen the adjacent disc on MRI using Pfirrmann grading. A grade >3 adjacent disc is already at high risk. Factor this into shared decision-making and consider whether the planned fusion length can be minimized. Patients who smoke or have hypertension carry independent risk that should be addressed before elective surgery where possible.
Post-operative sagittal alignment is a controllable outcome: restoring lumbar lordosis and normalizing L1-S1 SVA at the time of fusion reduces long-term adjacent segment stress. Preoperative PI (a fixed anatomic value) flags patients who need aggressive lordosis restoration to match their spinopelvic morphology.
This meta-analysis of 19 retrospective studies (2,896 patients) quantifies the incidence of radiographic adjacent segment degeneration (ASD) after posterior lumbar fusion. It systematically evaluates which demographic, surgical, and sagittal alignment factors independently drive that risk. The goal is to give spine surgeons a prioritized, evidence-based checklist of modifiable and non-modifiable ASD risk factors.
The choice of PLIF vs. TLIF and whether to fuse to S1 have long been debated as potential drivers of adjacent segment disease. This meta-analysis clarifies that neither technique choice nor graft type meaningfully changes ASD risk — attention should shift to what actually matters.
The most actionable finding: protect the superior facet of the adjacent level at all costs. An OR of nearly 30 means a violated facet joint makes ASD almost inevitable. Use fluoroscopy or navigation to confirm screw trajectory, and be deliberate with retractor placement at the cranial end of your construct.
For pre-operative planning, screen the adjacent disc on MRI using Pfirrmann grading. A grade >3 adjacent disc is already at high risk. Factor this into shared decision-making and consider whether the planned fusion length can be minimized. Patients who smoke or have hypertension carry independent risk that should be addressed before elective surgery where possible.
Post-operative sagittal alignment is a controllable outcome: restoring lumbar lordosis and normalizing L1-S1 SVA at the time of fusion reduces long-term adjacent segment stress. Preoperative PI (a fixed anatomic value) flags patients who need aggressive lordosis restoration to match their spinopelvic morphology.