Analysis reveals patterns of complications in patients having adult spinal deformity surgery

Predicting complications in patients having surgery for adult spinal deformity (ASD) can be challenging, due to the diversity of patient presentations, outcomes, and complications. A team of researchers recently conducted a retrospective review to identify patterns of complications, which may inform optimization and prevention strategies. Their findings were presented at the AAOS 2025 Annual Meeting by Peter G. Passias, MD, FAAOS, neurosurgeon and orthopaedic spine surgeon at Duke Health.

“The emergence of the significance of complications and adverse events in spinal surgery, and spinal deformity surgery in particular, has grown in recent years in terms of impact and importance. Quantifying the occurrence has to date been unreliable and nonquantifiable,” Dr. Passias told AAOS Now. “Another gap in our knowledge is the distinction between predicting surgical- and medical-related complications. This study attempts to address these voids in risk assessment.”

The researchers analyzed data from 523 patients undergoing ASD surgery who had complete baseline and two-year follow-up data. The main foci were timing and type of complications. The patients’ mean age was 60.2 years, mean BMI was 27.1 kg/m2, mean Charlson Comorbidity Index was 1.63, and mean modified Adult Spinal Deformity Frailty Index was 6.4. Their average time in surgery was 415.9 minutes; they had an average estimated blood loss of 1,580.9 mL and an average of 11.0 levels fused per patient.

Of the total cohort, eight patients (1.5%) experienced a major intraoperative complication and 51 (9.8%) had a minor intraoperative complication. Perioperatively, 18 patients (3.4%) had a major complication, and 30 (5.7%) had a minor perioperative complication.

The researchers found that older age was a statistically significant predictor of intraoperative and perioperative complications. Additionally, comorbidities did not predict intraoperative complications. However, clotting disorders, kidney disease, and osteoporosis significantly increased the risk of perioperative complications. Patients with diabetes or heart disease had a higher rate of perioperative renal complications, including renal failure.

Other notable findings included:

• Perioperative complications predicted a longer hospital stay.
• Patients with heart disease, hypertension, kidney disease, or osteoporosis were more likely to have perioperative motor deficits.
• Patients with preexisting lung disease or peripheral vascular disease were more likely to experience deep vein thrombosis.

he authors said the findings highlight the importance of several proactive strategies in certain patients, such as preoperative neurological assessments, presurgical optimization for certain conditions, more stringent intraoperative monitoring, prophylactic measures for thrombotic events, and enhanced postoperative rehabilitation.

“The results underscore the complex interplay between patient characteristics and surgical outcomes in ASD surgery,” Dr. Passias said. “Medical and surgical risk tools can be equally developed, but the factors are not necessarily identical, and the risks need to be considered both collectively and individually given that they are interrelated but have distinct contributions.”

He highlighted that orthopaedic teams can use this information as a simple risk-assessment tool before surgical intervention to help build a tailored approach to patient management based on individual risk factors.

The researchers plan to build upon this pilot study to create a tool that helps orthopaedic teams easily conduct both surgical and medical risk assessment.

Dr. Passias’ co-authors of “Which complications when? Individualized complications calculator for adult spinal deformity surgeries” are Aaron Hockley, FRCSC; Alan H. Daniels, MD, FAAOS; Ankita Das, BS; Anthony Yung; Bassel Diebo, MD; Ethan Cottrill; Jamshaid Mir, MD; Jordan Lebovic, MD, MBA; Matthew Galetta, MD; Max R. Fisher, MD; Nathan A. Lorentz, MD; Shaleen Vira, MD, FAAOS; Tobi Onafowokan, MBBS, MRCS, MSc; and Tyler K. Williamson, DO,MS.

Keightley Amen, BA, ELS, is a freelance writer for AAOS Now.