National Administrative Databases in Adult Spinal Deformity Surgery: A Cautionary Tale

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Study Design.

Comparison between national administrative databases and a prospective multicenter physician managed database.


This study aims to assess the applicability of National Administrative Databases (NADs) in adult spinal deformity (ASD). Our hypothesis is that NADs do not include comparable patients as in a physician-managed database (PMD) for surgical outcomes in adult spinal deformity.

Summary of Background Data.

NADs such as National Inpatient Sample (NIS) and National Surgical Quality Improvement Program (NSQIP) provide large numbers of publications owing to ease of data access and lack of IRB approval requirement. These databases utilize billing codes, not clinical inclusion criteria, and have not been validated against PMDs in ASD surgery.


The NIS was searched for years 2002 to 2012 and NSQIP for years 2006 to 2013 using validated spinal deformity diagnostic codes. Procedural codes (ICD-9 and CPT) were then applied to each database. A multicenter PMD including years 2008 to 2015 was used for comparison. Databases were assessed for levels fused, osteotomies, decompressed levels, and invasiveness. Database comparisons for surgical details were made in all patients, and also for patients with ≥ 5 level spinal fusions.


Approximately, 37,368 NIS, 1291 NSQIP, and 737 PMD patients were identified. NADs showed an increased use of deformity billing codes over the study period (NIS doubled, 68x NSQIP, P < 0.001), but ASD remained stable in the PMD.


Surgical invasiveness, levels fused and use of 3-column osteotomy (3-CO) were significantly lower for all patients in the NIS (11.4–13.7) and NSQIP databases (6.4–12.7) compared with PMD (27.5–32.3). When limited to patients with ≥5 levels, invasiveness, levels fused, and use of 3-CO remained significantly higher in the PMD compared with NADs (P < 0.001).


National databases NIS and NSQIP do not capture the same patient population as is captured in PMDs in ASD. Physicians should remain cautious in interpreting conclusions drawn from these databases.Level of Evidence: 4

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