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

BACKGROUND CONTEXT: 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.

PURPOSE: To evaluate the neuroprotective efficacy of PCDM in patients with severe kyphoscoliosis and type 3 spinal cord morphology undergoing 3CO.

PATIENT SAMPLE: This study included 236 patients with severe kyphoscoliosis treated with 3CO.

OUTCOME MEASURES: Radiographic parameters, neurological status (Frankel grading), patient-reported outcomes (SRS-22), intraoperative neuromonitoring (IONM) alerts, and perioperative complications were analyzed and compared.

METHODS: 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.

RESULTS: 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).

CONCLUSION: 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.

STUDY DESIGN: Retrospective comparative cohort study.