Limited post-operative dexamethasone use does not affect lumbar fusion: a single institutional experience

The use of exogenous dexamethasone during and after lumbar spine surgery remains controversial. The preponderance of studies on this topic is primarily from animal models and little is known about the effects of exogenous dexamethasone use on fusion outcomes in human subjects undergoing lumbar arthrodesis. The aim of this study is to investigate the effect of limited exogenous dexamethasone use on bone fusion after instrumented lumbar arthrodesis.

Consecutive adult patients (18 years and older) undergoing one and two level lumbar decompression and fusion between January 2013 and December 2014 were reviewed. Patients were dichotomized into one of two groups (A & B) based on whether they received dexamethasone-Group (A) dexamethasone; and Group (B) no dexamethasone. Baseline characteristics, operative details, length of hospital stay, rates of wound infection, and fusion rates at 1 year were gathered by direct medical record review. All patients enrolled in this study were followed for a minimum of 12 months after surgery.

One hundred sixty-five consecutive patients undergoing 1- and 2-level fusions were included in the study. Fifty eight patients received dexamethasone and 107 patients did not. The mean ± SD age was similar between both cohorts ("dexamethasone": 58.12±16.25 years vs. "no dexamethasone": 61.00±12.95, P=0.24). The was no difference in the prevalence of smoking (P=0.72) between both cohorts. Length of in-hospital stay was similar between cohorts ("dexamethasone": 4.08±3.44 days vs. "no dexamethasone": 4.50±2.85 days, P=0.43). The incidence of post-operative infections was similar between cohorts. At 12 months after surgery, 70% of patients in the dexamethasone cohort had radiographic evidence of bony fusion compared to 73% of patients in the no-dexamethasone cohort (P=0.68).

Our study suggests that a limited exposure to exogenous dexamethasone after lumbar spine fusion may not be associated with a lower fusion rate. Prospective randomized control trials are needed to corroborate our findings.