The Importance of Preserving the Posterior Ligament Complex in Elective Lumbar Fusion Surgery: Early Results from a Single-Center Experience.

BACKGROUND

Adjacent segment disease (ASD) is a degenerative condition at the segment adjacent to a previously fused segment. Potential risk factors for ASD, such as posterior ligamentous complex (PLC) integrity between the upper instrumented vertebra (UIV) and the first unfused segment (UIV+1), have not been addressed. The objective of this study is to assess the PLC integrity between the UIV and UIV+1 following posterior lumbar decompression and fusion (PLDF).

METHODS

A retrospective review of 122 patients who received a PLDF was performed. Patients were divided into groups based on the integrity of the PLC between the UIV and the UIV+1: PLC disrupted and PLC intact. The development of ASD was assessed using standard radiographic parameters, and reoperation rates were reviewed.

RESULTS

Radiographic indicators for ASD were more common in patients of the PLC-deficient group-D and showed significantly higher mobility at the UIV+1 (p < 0.05). The overall surgical revision rate due to ASD was 7.4%, with group D (28 patients) exceeding the revision rate of group I (94 patients) by 4.3% (10.7% vs. 6.4%) over a mean follow-up of three years. The mean return to the operative report time at the UIV+1 was 2.4 years (± 1.7 years) after index surgery.

CONCLUSION

We demonstrated a significant increase in mobility at the UIV+1 in lumbar fusion in patients with disrupted PLC. PLC deficiency at UIV+1 appears to contribute to the development of ASD through instability and is implicated in higher surgical revision rates.