Abstract
Larger and more caudal lumbar pedicle subtraction osteotomies (PSOs) are associated with an increased risk of neurological deficits after adult spinal deformity (ASD) surgery.
In patients undergoing lumbar PSO, we evaluated the impact of PSO level and size on postoperative motor deficits.
Retrospective analysis of a prospective multicenter study.
Patients in a prospective multicenter database, including patients undergoing L2-L5 PSOs. Primary exposures were: 1) PSO level: upper lumbar (L2/3) and lower lumbar (L4/5), and 2) PSO size (angle).
Primary outcomes were new motor deficits.
Bivariate and multivariable comparisons were performed, controlling for age, sex, body mass index, operative times, and a PSO level/size interaction term.
Of 162 patients undergoing L2-L5 PSOs, mean age was 63 years, and 66% were female. Overall rate of new motor deficits was 8.6%.
62.3% of PSOs were upper lumbar (L2/3), while 37.7% were lower lumbar (L4/5). PSO level was not significantly associated with development of new motor deficit (10.9% vs 4.9%, p=0.190).
Mean PSO size was 29.8°±11.3°, with upper lumbar PSOs being significantly larger than lower lumbar PSOs (31.2°±10.6° vs 27.3°±12.1°, p=0.033). As a continuous variable, PSO size was not associated with new motor deficits (p>0.05).
A larger, caudal PSO was independently associated with decreased odds of new motor deficits (OR 0.85, 95% CI 0.74-0.97, p=0.020).
In ASD patients undergoing lumbar PSO, neither osteotomy level nor size alone was associated with postoperative motor deficits. However, when accounting for the interaction between level and size, larger and lower (L4/L5) PSOs were significantly associated with a reduced likelihood of developing motor deficits.
This abstract does not discuss or include any applicable devices or drugs.