Rates of Mortality in Lumbar Spine Surgery and Factors Associated With Its Occurrence Over a 10-Year Period: A Study of 803,949 Patients in the Nationwide Inpatient Sample

Abstract

Background: The rate of mortality in surgical procedures involving the lumbar spine has historically been low, and as a result, there has been difficulty providing accurate quantitative mortality rates to patients in the preoperative planning phase. Awareness of these mortality rates is essential in reducing postoperative complications and improving outcomes. Additionally, mortality rates can be influenced by procedure type and patient profile, including demographics and comorbidities. The purpose of this study is to assess rates and risk factors associated with mortality in surgical procedures involving the lumbar spine using a large national database.

Methods: The Nationwide Inpatient Sample database was reviewed from 2003 to 2012. A total of 803,949 patients age 18 years or older were identified by ICD-9CM procedure codes for spinal fusion or decompression of the lumbar spine. Mortality was stratified based on type of procedure (simple or complex fusion, decompression), patient demographics and comorbidities, and in-hospital complications. Binary logistic regression was used to identify the risk of death while controlling for comorbidities, race, sex, and procedure performed. Significance was defined as P < .05 differences relative to the overall cohort.

Results: Mortality for all patients requiring surgery of the lumbar spine was 0.13%. Mortality based on procedure type was 0.105% for simple fusions, 0.321% for complex fusions, and 0.081% for decompression only. Increased mortality was observed demographically in patients who were male (odds ratio [OR]: 1.75; 95% confidence interval [CI]: 1.51-2.03), black (OR: 1.40; CI: 1.10-1.79), ages 65-74 (OR: 1.46; CI: 1.25-1.70), and age 75+ (OR: 2.70; CI: 2.30-3.17). Comorbidities associated with the greatest increase in mortality were mild (OR: 10.04; CI: 7.76-13.01) and severe (OR: 26.47; CI: 16.03-43.70) liver disease and congestive heart failure (OR: 4.57; CI: 3.77-5.53). The complications with the highest mortality rates were shock (OR: 20.67; CI: 13.89-30.56) and pulmonary embolism (OR: 20.15; CI: 14.01-29.00).

Conclusions: From 2003 to 2012, the overall mortality rate in 803,949 lumbar spine surgery patients was 0.13%. Risk factors that were significantly associated with increased mortality rates were male gender, black race, and ages 65-74 and 75+. Comorbidities associated with an increased mortality rate were mild and severe liver disease and congestive heart failure. Inpatient complications with the highest mortality rates were shock and pulmonary embolism. These findings can be helpful to surgeons providing preoperative counseling for patients considering elective lumbar procedures and for allocating resources to treat and prevent perioperative complications leading to mortality.

Level of evidence: 3.

Keywords: NIS database; lumbar spine surgery; mortality incidence.

Conflict of interest statement

Disclosures and COI: Gregory Wyatt Poorman, John Y. Moon, Charles Wang, Samantha R. Horn, Bryan M. Beaubrun, Olivia J. Bono, Anne-Marie Francis, and Cyrus M. Jalai all report no conflict of interest. Peter G. Passias reports consulting with Medicrea and Zimmer, unrelated to and outside of the current work. All other authors report no conflicts of interest. Given the deidentified nature of the data reported from this study, it is exempt from IRB approval.

Figures

Figure 1

Results of trend analysis by analysis of variance, describing a significant change in mortality rate over 2003–2012.