Impact of patient and hospital-level risk factors on extended length of stay following spinal fusion for adolescent idiopathic scoliosis

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Health policy changes have led to increased emphasis on value-based care to improve resource utilization and reduce inpatient hospital length of stay (LOS). Recently, LOS has become a major determinant of quality of care and resource utilization. For adolescent idiopathic scoliosis (AIS), the determinants of extended LOS after elective posterior spinal fusion (PSF) remain relatively unknown. In the present study, the authors investigated the impact of patient and hospital-level risk factors on extended LOS following elective PSF surgery (≥ 4 levels) for AIS.


The Kids’ Inpatient Database (KID) was queried for the year 2012. Adolescent patients (age range 10–17 years) with AIS undergoing elective PSF (≥ 4 levels) were selected using the International Classification of Diseases, Ninth Revision, Clinical Modification coding system. Extended hospital LOS was defined as greater than the 75th percentile for the entire cohort (> 6 days), and patients were dichotomized as having normal LOS or extended LOS. Patient demographics, comorbidities, complications, LOS, discharge disposition, and total cost were recorded. A multivariate logistic regression model was used to determine the odds ratio for risk-adjusted LOS. The primary outcome was the degree to which patient comorbidities or postoperative complications correlated with extended LOS.


Comorbidities were overall significantly higher in the extended-LOS cohort than the normal-LOS cohort. Patients with extended LOS had a significantly greater proportion of blood transfusion (p < 0.001) and ≥ 9 vertebral levels fused (p < 0.001). The overall complication rates were greater in the extended-LOS cohort (20.3% [normal-LOS group] vs 43.5% [extended-LOS group]; p < 0.001). On average, the extended-LOS cohort incurred $18,916 more in total cost than the normal-LOS group ($54,697 ± $24,217 vs $73,613 ± $38,689, respectively; p < 0.001) and had more patients discharged to locations other than home (p < 0.001) than did patients in the normal-LOS cohort. On multivariate logistic regression, several risk factors were associated with extended LOS, including female sex, obesity, hypertension, fluid electrolyte disorder, paralysis, blood transfusion, ≥ 9 vertebrae fused, dural injury, and nerve cord injury. The odds ratio for extended LOS was 1.95 (95% CI 1.50–2.52) for patients with 1 complication and 5.43 (95% CI 3.35–8.71) for patients with > 1 complication.


The authors’ study using the KID demonstrates that patient comorbidities and intra- and postoperative complications all contribute to extended LOS after spinal fusion for AIS. Identifying multimodality interventions focused on reducing LOS, bettering patient outcomes, and lowering healthcare costs are necessary to improve the overall value of care for patients undergoing spinal fusion for AIS.

ABBREVIATIONS ACS NSQIP = American College of Surgeons National Surgical Quality Improvement Program; AIS = adolescent idiopathic scoliosis; BMP = bone morphogenetic protein; DVT = deep vein thrombosis; HTN = hypertension; ICD-9-CM = International Classification of Diseases, Ninth Revision, Clinical Modification; KID = Kids’ Inpatient Database; LOS = length of stay; PSF = posterior spinal fusion.

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Contributor Notes

Correspondence Michael L. DiLuna: Yale University School of Medicine, New Haven, CT. WHEN CITING Published online August 2, 2019; DOI: 10.3171/2019.5.PEDS19161.Disclosures The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.


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