Apex of deformity for three-column osteotomy. Does it matter in the occurrence of complications?

BACKGROUND: Posterior vertebral column resection (PVCR) is a challenging but effective technique for the correction of complex spinal deformity. However, it has a high complication rate and carries a substantial risk for neurologic injury. PURPOSE: The aim was to test whether the apex of the deformity influences the clinical outcomes and complications in patients undergoing PVCR. STUDY DESIGN: A historical cohort was recruited from a single center and evaluated preoperatively, postoperatively, and at final follow-up. PATIENT SAMPLE: Ninety-eight hyperkyphotic patients undergoing PVCR were included. Inclusion criteria consisted of kyphoscoliosis and hyperkyphosis surgically treated with PVCR as a primary or revision procedure. OUTCOME MEASURES: The outcome measures included a number of neurologic complications. METHODS: Receiver operator characteristic (ROC) curve analysis and Youden index (J) were used to estimate the optimum cut-off to predict neurologic complications for each potential risk factor. In three ROC analyses, we included separately body mass index (BMI), kyphosis degree, and age as independent variables and neurologic complications as the dependent variable. Logistic regression was used to estimate the odds ratios (ORs) and construct 95% confidence intervals (CIs). RESULTS: Among the 98 patients, the etiologies were: post infectious (50), congenital (31), and others (17). The averages were: age 14±6.5 years, BMI 20±10 kg/m(2), American Society of Anesthesiologists 3±0.7, forced vital capacity 76±23%, fusion levels 10±3, estimated blood loss 1,319±720 mL, surgical time 375±101 minutes, and preoperative localized kyphosis 104±30°. Thirty-three patients had abnormal preoperative neurologic status. Major complications occurred in 46 patients (neurologic in 25). The apex of kyphosis was proximal thoracic T1-T5 (five patients), thoracic (TH) T6-T9 (17 patients), thoracolumbar T10-L2 (55 patients), and lumbar L3-S1 (nine patients). The level of apex and BMI were independent risk factors for neurologic complications: TH apex (OR: 101.30, 95% CI: 1.420-infinite; p=.037); BMI (OR: 1.92, 95% CI: 1.110-infinite; p=.026). CONCLUSIONS: Posterior vertebral column resection for severe spine deformity is technically demanding and carries a substantial risk. The apex is a variable that influences the occurrence of neurologic complications, and the presence of a TH apex in particular could be a preoperative risk factor for neurologic complications.