A Novel Lumbar Motion Segment Classification to Predict Changes in Segmental Sagittal Alignment After Lateral...

Area of Science:

• Spine surgery
• Orthopedic research
• Biomechanical analysis

Background:

• Lateral interbody fusion is increasingly used for lumbar spine correction.
• Posterior facet joint hypertrophy can impact postoperative sagittal alignment.
• Predicting correction is crucial for successful surgical outcomes.

Purpose of the Study:

• To introduce a novel preoperative motion segment classification system (MSG).
• To predict postoperative segmental sagittal alignment after lateral lumbar interbody fusion.
• To correlate facet joint osseous anatomy with surgical correction.

Main Methods:

• Retrospective cohort study analyzing CT scans from 3 institutions.
• Facet joints were graded (0-2), summed for a motion segment grade (MSG 0-4).
• Segmental lordosis measured pre- and post-operatively; % graft lordosis (%GL) calculated.

Main Results:

• 59 operated levels in 36 patients analyzed.
• Mean %GL decreased significantly with increasing MSG (MSG 0: 115% to MSG 4: 5%).
• MSG was a significant predictor of postoperative %GL (P < .01).

Conclusions:

• A novel facet-based motion segment classification system was developed.
• This MSG system significantly predicts postoperative segmental lordosis.
• The classification aids in anticipating surgical correction in lateral lumbar interbody fusion.