Bicortical Lateral Plate Screw Placement Reduces Subsidence Risk in Patients Undergoing Lateral Lumbar Interbody...

Area of Science:

• Spine surgery
• Orthopedic surgery
• Minimally invasive spine procedures

Background:

• Lateral Lumbar Interbody Fusion (LLIF) is a minimally invasive technique for neural decompression.
• Postoperative subsidence remains a significant complication following LLIF procedures.
• Understanding factors influencing subsidence is crucial for improving patient outcomes.

Purpose of the Study:

• To investigate the impact of lateral plate screw placement techniques on postoperative subsidence after LLIF.
• To identify specific screw placement strategies that may mitigate subsidence risk.
• To analyze the relationship between screw type and subsidence rates.

Main Methods:

• Retrospective review of 144 patients (218 levels) from 2014-2022 at two quaternary centers.
• Radiographic assessment of subsidence, bony fusion, and screw length.
• Statistical analysis including T-tests, Chi-squared/Fisher's exact tests, and logistic regression.

Main Results:

• 12% of operative levels (27/218) experienced subsidence.
• Subsidence rates varied significantly with cage material, lateral plating, number of levels, and screw type.
• Multivariate analysis indicated bicortical screws significantly reduced subsidence odds (OR: 0.291, p=0.016).
• Unicortical screws did not show a significant reduction in subsidence odds compared to no plating (OR: 0.402, p=0.125).

Conclusions:

• Bicortical screw placement appears to be a protective factor against postoperative subsidence in LLIF.
• This finding suggests optimizing screw technique can improve LLIF safety and efficacy.
• Further research may validate bicortical screw placement as a standard preventative measure for subsidence.