Frequency and Implications of Concurrent Complications Following Adult Spinal Deformity Corrective Surgery

Cole Bortz, BA; Katherine E. Pierce, BS; Avery Brown, MD; Haddy Alas, MD; Lara Passfall, BS; Oscar Krol, BA; Nicholas A. Kummer, BS; Erik Wang, BS; Brooke O'Connell, MS; Charles Wang, MD; Dennis Vasquez-Montes, MS; Bassel G. Diebo, MD; Brian J. Neuman, MD; Michael C. Gerling, MD; Peter G. Passias, MD


Spine. 2021;46(21):E1155-E1160. 

In This Article

Abstract and Introduction


Study Design: Retrospective review.

Objective: Identify co-occurring perioperative complications and associated predictors in a population of patients undergoing surgery for adult spinal deformity (ASD).

Summary of Background Data: Few studies have investigated the development of multiple, co-occurring complications following ASD-corrective surgery. Preoperative risk stratification may benefit from identification of factors associated with multiple, co-occurring complications.

Methods: Elective ASD patients in National Surgical Quality Improvement Program (NSQIP) 2005 to 2016 were isolated; rates of co-occurring complications and affected body systems were assessed via cross tabulation. Random forest analysis identified top patient and surgical factors associated with complication co-occurrence, using conditional inference trees to identify significant cutoff points. Binary logistic regression indicated effect size of top influential factors associated with complication co-occurrence at each factor's respective cutoff point.

Results: Included: 6486 ASD patients. The overall perioperative complication rate was 34.8%; 28.5% of patients experienced one complication, 4.5% experienced two, and 1.8% experienced 3+. Overall, 11% of complication co-occurrences were pulmonary/cardiovascular, 9% pulmonary/renal, and 4% integumentary/renal. By complication type, the most common co-occurrences were transfusion/urinary tract infection (UTI) (24.3%) and transfusion/pneumonia (17.7%). Surgical factors of operative time ≥400 minutes and fusion ≥9 levels were the strongest factors associated with the incidence of co-occurring complications, followed by patient-specific variables like American Society of Anesthesiologists (ASA) physical status classification grade ≥2 and age ≥65 years. Regression analysis further showed associations between increasing complication number and longer length of stay (LOS), (R 2 = 0.202, P < 0.001), non-home discharge (R 2 = 0.111, P = 0.001), and readmission (R 2 = 0.010, P < 0.001).

Conclusion: For surgical ASD patients, the overall rate of co-occurring perioperative complications was 6.3%. Body systems most commonly affected by complication co-occurrences were pulmonary and cardiovascular, and common co-occurrences included transfusion/UTI (24.3%) and transfusion/pneumonia (17.7%). Increasing number of perioperative complications was associated with greater LOS, non-home discharge, and readmission, highlighting the importance of identifying risk factors for complication co-occurrences.

Level of Evidence: 3


Significant progress has been made in the last decade in the evaluation and management of adult spinal deformity (ASD).[1] Several studies have documented the benefits of ASD-corrective surgery, which include substantial improvements in both sagittal alignment and health-related quality of life.[2,3] Despite these successes, however, complication risk following ASD-corrective surgery remains high, with some studies in the ASD literature reporting overall perioperative complication rates ranging from 30% to 70%.[4,5] Interestingly, although there exists a large body of literature exploring the types, rates, and risk factors associated with individual complications following ASD-corrective surgery, to date, there are few studies investigating co-occurring complications.[6]

Previous research shows that roughly 21% of patients undergoing ASD-corrective surgery may experience two perioperative complications, while another 20% may experience three or more.[5] It remains unclear, however, whether specific complications tend to co-occur together. Additionally, while previous studies have demonstrated a clear association between perioperative complication occurrence and substantial impairments in health-related quality of life, the relationship between multiple, co-occurring complications, and clinical outcomes is under-investigated in the surgical ASD literature.[7]

To better understand the complication risks associated with ASD-corrective surgery, it is important to assess whether relationships exist between complications, and if so, which complications tend to cluster together. Furthermore, to improve preoperative patient counseling and risk stratification, it is important to understand risk factors for complication co-occurrences. In a population of surgical ASD patients, this study aims to assess trends in co-occurring perioperative complications, and identify associated patient-related and surgical risk factors.