Which factor can predict the effect of indirect decompression using oblique lumbar interbody fusion?

Area of Science:

• Neurosurgery
• Orthopedic Surgery
• Spinal Surgery

Background:

• Indirect decompression is effective for spinal stenosis, but predictive factors lack consensus.
• Facet joint gap (FJG) and bulging disc thickness (BDT) have not been previously studied as predictive factors.
• Understanding these factors can optimize surgical outcomes for spinal stenosis.

Purpose of the Study:

• To investigate the association between various factors and indirect decompression outcomes.
• To identify predictive factors for successful indirect decompression, including FJG and BDT.
• To analyze the impact of OLIF L4/5 on spinal canal cross-sectional area (CSA) and stenosis grade.

Main Methods:

• Retrospective review of 62 patients undergoing OLIF L4/5.
• Measurement of ligamentum flavum thickness (LFT), foraminal area (FA), disc height (DH), BDT, and FJG.
• Correlation analysis between pre- and post-operative measurements and spinal stenosis grade.

Main Results:

• Significant increases in CSA (69.72 to 115.95 mm²) and FJG (Right: 2.99 to 4.38 mm; Left: 2.95 to 4.52 mm) post-operatively.
• Significant decrease in BDT (4.97 to 2.56 mm) post-operatively.
• Spinal stenosis grade improved, with FJG change ratio correlating significantly with indirect decompression outcomes (r=0.336, P=.008).

Conclusions:

• Facet joint gap (FJG) is a statistically significant factor in indirect decompression.
• Indirect decompression principles are applicable even for severe spinal canal stenosis (grade 4).
• FJG and BDT should be considered in future predictive models for indirect decompression success.