Imaging-Based Quantitative Assessment of Cage Migration After Minimally Invasive Lumbar Interbody Fusion

Area of Science:

• Spine surgery
• Orthopedic surgery
• Neurosurgery

Background:

• Posterior cage migration is a known complication following lumbar interbody fusion.
• Limited data exists on risk factors specific to minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF).

Purpose of the Study:

• To identify factors associated with cage migration and symptomatic retropulsion after MIS-TLIF.
• To evaluate the incidence and predictors of cage migration in a large MIS-TLIF cohort.

Main Methods:

• Retrospective review of 650 patients (1126 fused segments) undergoing MIS-TLIF.
• Definition of cage migration as posterior displacement >3 mm on radiographs.
• Comparison of demographic, clinical, surgical, and radiographic variables between migrated and non-migrated segments.

Main Results:

• Cage migration occurred in 2.4% of levels; 0.6% required revision for symptomatic retropulsion.
• Posterior initial cage placement was significantly associated with migration.
• Male sex correlated with higher revision odds; mechanical parameters did not predict progression to symptomatic retropulsion.

Conclusions:

• Posterior initial cage placement is a key risk factor for cage migration in MIS-TLIF.
• Progression from radiographic migration to symptomatic retropulsion is multifactorial.
• Meticulous cage positioning and careful postoperative surveillance are crucial in MIS-TLIF.