Perioperative morbidity and mortality after anterior, posterior, and anterior/posterior spine fusion surgery

Abstract

Study design: Analysis of population-based national hospital discharge data collected for the National Inpatient Sample.

Objective: To examine demographics of patients undergoing primary anterior spine fusion (ASF), posterior spine fusion (PSF), and anterior/posterior spine fusion (APSF) of the noncervical spine, assess the incidence of perioperative morbidity and mortality, and determine independent risk factors for in-hospital death.

Summary of background data: The utilization of surgical fusion has been increasing dramatically. Despite this trend, a paucity of literature addressing perioperative outcomes exists.

Methods: Data collected for each year between 1998 and 2006 for the National Inpatient Sample were analyzed. Discharges with a procedure code for primary noncervical spine fusion were included in the sample. The prevalence of patient as well as health care system-related demographics were evaluated by procedure type (ASF, PSF, and APSF). Frequencies of procedure-related complications and in-hospital mortality were analyzed. Independent predictors for in-hospital mortality were determined.

Results: We identified 261,256 entries representing an estimated 1,273,228 hospitalizations for primary spine fusion. Patients undergoing ASF and APSF were significantly younger (44.8 ± 0.08 and 44.22 ± 0.11 years) and had lower average comorbidity indeces (0.30 ± 0.002 and 0.31 ± 0.004) than those undergoing PSF (52.12 ± 0.04 years and 0.41 ± 0.002) (P < 0.0001). The incidence of procedure-related complications was 18.68% among ASF, 15.72% in PSF, and 23.81% in APSF patients (P < 0.0001). In-hospital mortality rates after APSF were approximately twice those of PSF (0.51 ± 0.038 vs. 0.26 ± 0.012) (P < 0.0001). Adjusted risk factors for in-hospital mortality included the following: APSF and ASF compared to PSF, male gender, increasing age, and increasing comorbidity burden. Several comorbidities and complications independently increased the risk for perioperative death, as did underlying spinal pathology.

Conclusion: Despite being performed in generally younger and healthier patients, APSF and ASF are associated with increased morbidity and mortality. Our findings can be used for the purposes of risk stratification, accurate patient consultation, and hypothesis formation for future research.

Figure 1

Depicted is the prevalence of studied comobidities by type of spine fusion. Error bars represent standard errors. P<0.0001 for all comorbidities between types of spine fusion.

Figure 2

The incidence of ARDS (Adult Respiratory Distress Syndrome), Pulmonary Embolism , and Venous Thrombosis is shown for the three types of spine fusion studied. P<0.0001 for all adverse events between types of spine fusion.

Figure 3

Shown is the incidence of procedure related complications (ICD-9-CM 996.X to 999.X) for various surgical sites. P<0.0001

Figure 4

Illustrated is the incidence of in-hospital mortality for various surgical sites. P=0.0001

Figure 5

Shown is the prevalence of studied comorbidities among non-fatalities and fatalities after spine fusion surgery. P<0.0001 for all comorbidities, except uncomplicated diabetes mellitus (P= 0.7056).