Posterior surgery in high-grade spondylolisthesis.

Area of Science:

• Spine surgery
• Orthopedic surgery
• Radiology

Background:

• High-grade L5-S1 spondylolisthesis disrupts sagittal spinopelvic balance, potentially causing low back pain and neurological deficits.
• Surgical intervention is necessary to correct slippage and restore spinal alignment.

Purpose of the Study:

• To compare the effectiveness of L4-S1 versus L5-S1 posterior fusion using a lever-arm system for spondylolisthesis reduction and maintenance.
• To assess changes in spinopelvic parameters and segmental lordosis over time.

Main Methods:

• Retrospective analysis of 40 patients with symptomatic high-grade spondylolisthesis, with 34 having complete radiological data.
• Comparison of L4-S1 (n=25) versus L5-S1 (n=9) instrumentation groups.
• Evaluation of spinopelvic parameters, slipping index, and lordosis evolution over a mean 5.4-year follow-up.

Main Results:

• The lever-arm system significantly reduced the Taillard spondylolisthesis index (64% to 37%).
• L4-S1 fusion demonstrated superior long-term maintenance of L5-S1 lordosis reduction compared to L5-S1 fusion (P=0.006).
• Overall sagittal spinopelvic balance and L1-S1 lordosis remained largely unchanged post-operatively.

Conclusions:

• The lever-arm system effectively reduces spondylolisthesis and corrects slippage with stable postoperative spinopelvic balance.
• Posterior L4-S1 fusion offers better long-term control of L5-S1 lordosis reduction compared to L5-S1 fusion.
• This study highlights the benefits of longer fusion constructs for maintaining reduction in high-grade spondylolisthesis.