Is Pelvic Fixation a Risk Factor for Pelvic Incidence Change After Surgery for Adult Spinal Deformity? A...

Area of Science:

• Spine surgery
• Orthopedic surgery
• Adult spinal deformity

Background:

• Adult spinal deformity (ASD) surgery aims to restore sagittal spinal alignment for improved quality of life.
• Pelvic incidence (PI) is a key parameter for alignment, traditionally considered constant.
• Recent evidence suggests PI can change after ASD surgery.

Purpose of the Study:

• To evaluate if pelvic fusion influences post-operative pelvic incidence (PI) modification in adult spinal deformity (ASD) patients.
• To identify risk factors associated with PI changes after ASD surgery.

Main Methods:

• Retrospective analysis of prospectively collected data from 290 ASD patients (2012-2022).
• Patients divided into two groups: those who underwent pelvic fusion (Group A) and those who did not (Group B).
• PI change defined as ≥ 6° difference between pre- and post-operative values; pre-operative PI categorized as low, medium, or high.

Main Results:

• 80.0% of patients with pelvic fusion (Group A) experienced PI change versus 12.8% without (Group B) (OR=27.2, P<.001).
• PI change was more frequent in males (P=0.02).
• Logistic regression identified pelvic fusion as the only independent predictor of post-operative PI change (aOR=26.3).

Conclusions:

• Post-operative PI change of ≥ 6° occurred in 32.1% of ASD patients, consistent with literature.
• Pelvic fusion is the sole independent risk factor for post-operative PI change in ASD surgery.