Prophylactic Concave-side Decompression and Spinal Cord Medialization Reduces Neurological Complications in Severe Kyphoscoliosis with Type 3 Cord Morphology.

Abstract

Type 3 spinal cord morphology increases neurological injury risk during three-column osteotomy (3CO). Prophylactic Concave-side Decompression and Spinal Cord Medialization (PCDM) is proposed to relieve cord tension, but its clinical utility requires validation. To evaluate the neuroprotective efficacy of PCDM in patients with severe kyphoscoliosis and type 3 spinal cord morphology undergoing 3CO. Retrospective comparative cohort study. This study included 236 patients with severe kyphoscoliosis treated with 3CO. Radiographic parameters, neurological status (Frankel grading), patient-reported outcomes (SRS-22), intraoperative neuromonitoring (IONM) alerts, and perioperative complications were analyzed and compared. The PCDM group (n=132) underwent prophylactic multi-level resection of concave laminae, pedicles, and costovertebral elements to create a medial transposition corridor before 3CO. The non-PCDM group (n=104) received standard 3CO alone. Baseline demographics and preoperative radiographic profiles were comparable between groups. Both cohorts achieved substantial deformity correction. The PCDM group showed significant reductions in coronal Cobb angle (80.8° to 42.2°) and global kyphosis (71.7° to 27.6°), similar to the non-PCDM group (76.7° to 39.6° and 66.3° to 25.2°, respectively). Notably, the PCDM group exhibited a significantly lower rate of permanent neurological deficits compared to the non-PCDM group (1.5%, 2/132 vs. 6.7%, 7/104; p=0.046). IONM alert rates were also lower in the PCDM group (8.3% vs. 20.2%, p = 0.012). Among patients with preoperative deficits, neurological recovery was more frequent in the PCDM group (86.7% vs. 50.0%, p = 0.009). Perioperative complication rates were not significantly different (13.6% vs. 19.2%, p = 0.246). PCDM appears to offer neuroprotective benefits in high-risk 3CO procedures for patients with type 3 spinal cord morphology, with reduced neurological complications and improved functional outcomes. Its use as a preparatory step prior to osteotomy may be considered as a beneficial adjunct in selected severe deformity cases.