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Readmissions, Length of Stay, and Mortality After Primary Surgery for Adult Spinal Deformity

A 10-Year Danish Nationwide Cohort Study

Pitter, Frederik T., MD; Lindberg-Larsen, Martin, MD, PhD; Pedersen, Alma B., MD, PhD, DMSc; Dahl, Benny, MD, PhD, DMSc§; Gehrchen, Martin, MD, PhD

doi: 10.1097/BRS.0000000000002782

Study Design. Cohort study.

Objective. To report outcome after primary surgery for adult spinal deformity (ASD), and assess risk factors for extended length of stay (extLOS) and readmission within 90 days.

Summary of Background Data. Complications after ASD surgery have been reported in 20% to 50% of patients. A few studies have focused on detailed information concerning postoperative morbidity.

Methods. Patients >18 years undergoing primary instrumented surgery for ASD in Denmark in the period 2006 to 2016 were included. Patients were identified in the Danish National Patient Registry (DNPR) using procedure codes for instrumented spine surgery combined with diagnosis of spinal deformity. Information on length of stay (LOS), readmissions, and mortality were retrieved from the DNPR. Medical records were reviewed for causes of extLOS (LOS >10 days) and readmission within 90 days after surgery. Charlson Comorbidity Index (CCI) was calculated for all patients based on DNPR.

Results. We included 892 patients. Median LOS was 8 days (interquartile range, IQR, 7–11). A total of 175 (28.0%) patients had extLOS; 81% because of “medically” related complications. Most common medically related reason (>50%) for extLOS was pain/mobilization difficulties. The 90-days readmission risk was 13.8%; 74.5% of readmissions were “medically” related, primarily opioid related side effects (18.2%), and pain/mobilization issues (15.2%); 25.5% of readmissions were “surgically” related and 16.7% of patients required revision surgery. Ninety-days mortality was 0.9%. Age groups 61 to 70 years, >70 years, CCI score 1 to 2 and CCI score ≥3 were associated with increased risk of extLOS (odds ratio, OR = 1.79, 2.01, 1.81, and 2.49, respectively). Age group >70 years and CCI score 1 to 2 were associated with increased risk of readmission (OR = 2.21 and 1.83).

Conclusion. Increasing age and comorbidity were associated with increased risk extLOS and readmission. Pain/mobilization difficulties were the most common postoperative complications. A future focus on early mobilization and pain management may improve outcome of ASD patients.

Level of Evidence: 3

Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, Denmark

Department of Orthopedic Surgery and Traumatology, Odense University Hospital, Odense, Denmark

Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark

§Department of Orthopedic Surgery, Texas Children's Hospital and Baylor College of Medicine, Houston, TX.

Address correspondence and reprint requests to Frederik T. Pitter, MD, Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, University Hospital of Copenhagen, Blegdamsvej 9 - 2100 København Ø, Copenhagen, Denmark; E-mail:

Received 4 May, 2018

Revised 14 June, 2018

Accepted 18 June, 2018

The manuscript submitted does not contain information about medical device(s)/drug(s).

No funds were received in support of this work.

Relevant financial activities outside the submitted work: grants.

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