Sagittal deformity correction and Patient Reported Outcomes with Schwab 4 osteotomy and a large footprint cage

Introduction: Modified subtraction osteotomy techniques are sometimes underutilized due to
reported high morbidity rates and a lack of clear data regarding patient-reported outcomes. This
study aims to present our experience with the Schwab 4 osteotomy using a large footprint cage and explore the associated
radiographic and patient reported outcomes.

Methods: Patients were included if they underwent a Schwab Type IV osteotomy, and the addition of a lordotic cage with a large footprint at the
osteotomy site. We recorded patient demographics, surgical variables, preoperative and postoperative radiographic parameters, and patient outcomes.

Results: The retrospective analysis included data from 26 patients who had a follow up of at least 6 months’ post op. The patient
mean age was 65.2+/-7.8 years, the average intraoperative bleeding was 1684 ± 625 ml, surgical duration averaged 532 ± 72 minutes, and the mean number of fused levels was 10.26±3.35. Ten patients (38%) experienced postoperative complications, with surgical site infections being the most common (40%), followed by deep vein thrombosis and delirium (20% each). Radiographic parameters showed significant improvement after surgery: sagittal vertical axis mean change was 6.7 ± 0.7 cm (p < 0.001) and lumbar mismatch change was 32+/- 14° (p < 0.001), the change in segmental lordosis was 38+/-10° (p < 0.001).
Patient-reported outcomes also improved significantly, with the Oswestry disability index decreasing from 35 ± 8 to 22 ± 9 (p < 0.001), and the SRS-22r demonstrating increased satisfaction in pain (0.99±1.3, p < 0.00 1), self-image (1.03±0.86, p< 0.001) activity (0.31, p < 0.001), function (0.84±0.7, p< 0.001), and satisfaction with management (1.38±1.29 p< 0.001).

Conclusion : The Schwab 4 osteotomy, despite its associated morbidity, demonstrated significant improvements in patient-reported outcomes and radiographic parameters. This technique can positively impact the quality of life for patients with severe sagittal misalignment who have
previously undergone multiple surgical procedures.