The Impact of Anterior Vertebral Body Tethering on Pulmonary Function.

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STUDY DESIGN: Retrospective, single-center study.

OBJECTIVE: To examine pulmonary function tests (PFTs) in patients undergoing anterior vertebral body tethering (AVBT).

SUMMARY OF BACKGROUND DATA: The effect of AVBT on pulmonary status remains unclear.

METHODS: We examined preoperative and postoperative PFTs following AVBT in a retrospective, single-center cohort of patients. Outcomes were compared using percent predicted values as continuous and categorical variables (using 10% change as significant) and divided into categorical values based on the American Thoracic Society (ATS) standards.

RESULTS: 58 patients with adolescent idiopathic scoliosis were included with a mean age of 12.5±1.4 years and follow-up of 4.2±1.1 years. The mean thoracic curve was 47°±9°, which improved to 21°±12°. At baseline, the mean FEV1% and FVC% values were 79% and 82%, respectively. Four patients had normal FEV1% (≥100%), 67% had mild restrictive disease (70-99%), and the rest had worse FEV1%. Mean FEV1 improved from 2.2 to 2.6 L (P0.05) with mean postoperative PFTs at 37±12 months postoperative. The use of mini-open thoracotomy was not associated with worsening PFTs, but extension of the lowest instrumented vertebra below T12 was correlated with decreasing FEV1% in the bivariate analysis (P

CONCLUSION: Pulmonary function in most patients undergoing AVBT remained stable (76%) or improved (14%); however, a subset may worsen (10%). Further studies are needed to identify the risk factors for this group, but worse preoperative PFTs and extension below T12 may be risk factors for worsening pulmonary function.

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Spine (Phila Pa 1976)


online ahead of print

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