Complication rate evolution across a 10-year enrollment period of a prospective multicenter database

Adult spinal deformity is a complex pathology that benefits greatly from surgical treatment. Despite continuous innovation, little is known regarding continuous changes in surgical techniques and the complications rate. The objective of the current study was to investigate the evolution of the patient profiles and surgical complications across a single prospective multicenter database.

This study is a retrospective review of a prospective, multicenter database of surgically treated patients with adult spinal deformity (thoracic kyphosis > 60°, sagittal vertical axis > 5 cm, pelvic tilt > 25°, or Cobb angle > 20°) with a minimum 2-year follow-up. Patients were stratified into 3 equal groups by date of surgery. The three groups' demographic data, preoperative data, surgical information, and complications were then compared. A moving average of 320 patients was used to visualize and investigate the evolution of the complication across the enrollment period.

A total of 928/1260 (73.7%) patients completed their 2-year follow-up, with an enrollment rate of 7.7 ± 4.1 patients per month. Across the enrollment period (2008-2018) patients became older (mean age increased from 56.7 to 64.3 years) and sicker (median Charlson Comorbidity Index rose from 1.46 to 2.08), with more pure sagittal deformity (type N). Changes in surgical treatment included an increased use of interbody fusion, more anterior column release, and a decrease in the 3-column osteotomy rate, shorter fusion, and more supplemental rods and bone morphogenetic protein use. There was a significant decrease in major complications associated with a reoperation (from 27.4% to 17.1%) driven by a decrease in radiographic failures (from 12.3% to 5.2%), despite a small increase in neurological complications. The overall complication rate has decreased over time, with the lowest rate of any complication (51.8%) during the period from August 2014 to March 2017. Major complications associated with reoperation decreased rapidly in the 2014-2015. Major complications not associated with reoperation had the lowest level (21.0%) between February 2014 and October 2016.

Despite an increase in complexity of cases, complication rates did not increase and the rate of complications leading to reoperation decreased. These improvements reflect the changes in practice (supplemental rod, proximal junctional kyphosis prophylaxis, bone morphogenetic protein use, anterior correction) to ensure maintenance of status or improved outcomes.