Redefining global spinal balance: normative values of cranial center of mass from a prospective cohort of asymptomatic individuals.

STUDY DESIGN: Prospective radiographical analysis of cranial center of mass (CCOM), C2, and C7 plumb lines in young and elderly asymptomatic individuals. OBJECTIVE: To establish a normal range for craniosagittal balance for both young and elderly asymptomatic individuals. SUMMARY OF BACKGROUND DATA: Global sagittal balance must account for the position of the head in relation to the spine and pelvis. The C7 plumb line defines thoracolumbar sagittal balance and has been shown to have significant impact on patient outcomes. However, the C7 plumb line fails to take into consideration the position of the head in relation to the pelvis. METHODS: A total of 100 asymptomatic 20- to 40-year-old patients and 100 asymptomatic 60- to 80-year-old patients were enrolled. Standing plain radiographs of 14 × 36 in were obtained. CCOM, C2, and C7 plumb lines were drawn and measured from the superoposterior endplate of S1. RESULTS: A total of 78 asymptomatic 20- to 40-year-old patients and 62 asymptomatic 60- to 80-year-old patients had adequate radiographs. The mean plumb line values in the 20- to 40-year-old patients and 60- to 80-year-old patients, respectively, were as follows; CCOM 9.0 mm (SD, 31.5 mm) and 41.2 mm (SD, 35.7 mm); C2 -2.7 mm (SD, 32.7 mm) and 32.1 mm (SD, 33.6 mm); and C7 -16.4 mm (SD, 31.5 mm) and 10.6 mm (SD, 27.8 mm). One-way analysis of variance and Student t tests confirmed that these mean plumb line values were significantly different between young and elderly patients (P < 0.001). The change at each level over time was highly correlated with the other levels (r > 0.97; P < 0.001) as did the degree of change between groups (r > 0.90, P < 0.001). CONCLUSION: Spinopelvic alignment in conjunction with CCOM has increased our understanding of spinal balance by including the head and may better represent true global spinal balance. CCOM is an easily measured parameter by using the nasion-inion technique.

Single-stage thoracolumbar vertebrectomy with circumferential reconstruction and arthrodesis: surgical technique and results in 15 patients.

OBJECTIVE: Circumferential reconstruction and arthrodesis can be necessary after thoracolumbar vertebrectomy. The authors describe a technique for single-stage thoracolumbar vertebrectomy with circumferential reconstruction and arthrodesis. The surgical results using this technique are reviewed. METHODS: Fifteen patients ranging from 14 to 75 years of age underwent single-stage thoracolumbar vertebrectomy with circumferential reconstruction and arthrodesis. The vertebrectomy was performed through a posterior midline approach. Anterior column reconstruction was performed with expandable or nonexpandable cages. Anterior and posterolateral arthrodeses used autograft. Posterior segmental instrumentation was used in all cases. RESULTS: Fifteen procedures have been performed to date, 4 for tumor and 11 for fracture. The range of treated levels was T4 to L2 (7 thoracic spine and 8 lumbar spine levels). One patient was incomplete preoperatively (Frankel Grade C) and improved to being intact postoperatively (Frankel Grade E), another improved from Frankel Grade C to Frankel Grade D. All other patients were neurologically unchanged postoperatively. Mean operative time was 4.0 hours. Average blood loss was 1100 ml. Average number of levels fused was 5.8 (range 4-9). There were four complications: one delayed transient neurological deficit after deformity correction, one infection, one postoperative myocardial infarction, and one hardware failure. All patients were treated and had a good recovery. CONCLUSION: The authors present a method for thoracolumbar vertebrectomy, circumferential reconstruction, and arthrodesis performed in a single stage, solely via a posterior approach. This is an alternative to anterior (i.e., thoracoabdominal and retroperitoneal) and lateral (i.e., lateral extracavitary) approaches that can be used for circumferential reconstruction and arthrodesis. Potential advantages and pitfalls are discussed.