Complication Rates Following Adult Spinal Deformity Surgery: Evaluation of the Category of Complication and Chronology

Abstract

Objective: Provide benchmarks for the rates of complications by type and timing.

Study design: Prospective multicenter database.

Background: Complication rates following adult spinal deformity (ASD) surgery have been previously reported. However, the interplay between timing and complication type warrants further analysis.

Methods: The data for this study were sourced from a prospective, multicenter ASD database. The date and type of complication were collected and classified into three severity groups (minor, major, and major leading to reoperation). Only complications occurring before the two-year visit were retained for analysis.

Results: Of the 1260 patients eligible for two-year follow-up, 997 (79.1%) achieved two-year follow-up. The overall complication rate was 67.4% (N=672). 247 patients (24.8%) experienced at least one complication on the day of surgery (including intraoperatively), 359 (36.0%) between postoperative day 1 and six weeks postoperatively, 271 (27.2%) between six weeks and one-year postoperatively, and finally 162 (16.3%) between one year and two years postoperatively. Using Kaplan-Meier survival analysis, the rate of remaining complication-free was estimated at different time points for different severities and types of complications. Stratification by type of complication demonstrated that most of the medical complications occurred within the first 60 days. Surgical complications presented over two distinct timeframes. Operative complications, incision-related complications, and infections occurred early (within 60 d), while implant-related and radiographic complications occurred at a constant rate over the two-year follow-up period. Neurological complications had the highest occurrence within the first 60 days but continued to increase up to the two-year visit.

Conclusion: Only one-third of ASD patients remained complication-free by two years, and 2 of 10 patients had a complication requiring a reoperation or revision. An estimation of the timing and type of complications associated with surgical treatment may prove useful for more meaningful patient counseling and aid in assessing the cost-effectiveness of treatment.

Level of evidence: 3.