Passive surgical correction of rigid adult spine deformities to normative alignment and balance

Realizing an age-adjusted correction in adult spine deformities (ASD) is demanding. We focus on rigid ASD patients requiring three-column osteotomies (TCO) and analyze the capability to obtain a normative alignment. Additionally, we introduce a new age-adjusted alignment parameter: the C7-SA norm. We retrospectively included 26 patients (68.2 ± 1.6 years) with rigid ASD who underwent lumbar TCO for deformity correction. All patients were positioned on a ProAxis table (Mizuho OSI, USA) with the shoulders, hips and ankles aligned for passive correction without bending the surgical table. The mean pelvic incidence-lumbar lordosis, sagittal vertical axis, T1 pelvic angle, and C7-SA norm before and after surgery were as follows: 25.7 ± 2.9° versus 10.1 ± 1.4° (p < 0.001), 113.6 ± 9.8 mm versus 36.2 ± 4.9 mm (p < 0.001), 30.1 ± 2.3° versus 12.0 ± 1.4° (p < 0.001), and 85.7 ± 9.5 mm versus 30.6 ± 4.4 mm (p < 0.001), respectively. The mean correction of lumbar lordosis was 27.3 ± 3.2°. A C7-SA norm of ≥ 66.1 mm required a correction of lumbar lordosis of > 20.8° which confirmed the necessity to conduct a TCO. Realigning the C7-SA norm in rigid ASD by TCOs and optimal patient positioning is a simple method for age-adjusted deformity correction without the need for preoperative complex calculations, intraoperative measurements, and repositioning of the patient during surgery.