Improved Spinopelvic Parameters with the Use of Prone Lateral Interbody Fusion in Deformity Correction: A Multi-Institutional Experience

Introduction: Lateral spine surgery techniques offer potent, minimally invasive solutions for deformity correction. However, combining lateral approaches with anterior and posterior-based strategies often necessitates patient repositioning, which can be inefficient and costly. The prone lateral technique streamlines surgery, reducing operative time by allowing a single-position approach for lateral and posterior deformity correction, taking advantage of the lordosing effect in the prone position. While small studies have compared prone lateral to direct lateral for degenerative disease, its suitability for complex deformities remains unexplored. This study focuses on assessing outcomes in deformity patients undergoing prone lateral interbody fusion.

Methods: This retrospective review includes adult patients from 11 institutions who underwent single-position prone lateral spine deformity surgery from 2019 to 2022. Deformity was defined as pre-op sagittal vertical axis (SVA) > 5cm or pelvic incidence to lumbar lordosis (PI-LL) mismatch > 10. Demographic, perioperative, radiographic, and patient outcomes data were collected and analyzed using Student's t-test.

Results: The study included 107 patients with an average 7.3-month follow-up. The patient group was predominantly female (57%), with an average age of 65 (SD 10.7) and BMI of 34 (SD 16.3) kg/m2. Skin-to-skin time averaged 234 (SD 161.9) minutes, and the mean fluoroscopy dose was 112.8 (SD 98.7) mGy. Blood loss was 168.4 (SD 234.3) mL, and hospital stays averaged 2.7 (SD 2.2) days. Results revealed a 1.2 cm mean change in sagittal vertical axis (p=0.33). Lumbar lordosis improved by an average of +7.6 degrees (p=0.0001), and pelvic tilt increased by 3.5 degrees (p=0.004). Segmental lordosis across the full fusion construct showed a mean change of +5 degrees (p=0.002). The average decrease in PI-LL mismatch was 6.1 degrees (p=0.01). Visual Analog Scale (VAS) scores improved by 5 points (p=0.001), while Oswestry Disability Index (ODI) scores decreased by 5.7 points (p=0.29).

Conclusion : The prone lateral approach is a potent and safe method for treating deformities. In this study, spinopelvic parameters were significantly improved in deformity patients. Further research is needed to directly compare this technique with standard lateral approaches.