A retrospective controlled study of postoperative fever after posterior lumbar interbody fusion due to degenerative lumbar disease

BACKGROUND: Postoperative fever is a common feature of spinal surgery. When fever occurs postoperatively in patients, surgeons are eager to rule out an infection. There are many reports about postoperative fever and infection; however, only a few have described the relationship between degenerative spinal disease and postoperative fever. This study aimed to investigate the causes of postoperative fever in patients with degenerative lumbar disease undergoing posterior screw fixation and interbody fusion and compare patients with non-pathologic fever and infected febrile patients. METHODS: From March 2015 to February 2016, 263 patients with degenerative lumbar disease underwent posterior lumbar screw fixation and interbody fusion surgery in our institution. We performed risk factor analysis by categorizing patients as afebrile and febrile. Comparisons were made between afebrile patients and patients with non-pathologic fever, and an analysis was performed between patients with non-pathologic fever and patients with febrile infection. We compared each group by examining the demographic factors before surgery, surgery features, drain duration, and postoperative transfusion. The postoperative day (POD) of fever onset, postoperative fever duration, and blood sample results in patients with fever were investigated. RESULTS: The drain duration was found to be an important factor between the afebrile febrile groups and between the non-pathologic fever and afebrile groups. POD of fever occurred earlier in the non-pathologic group than in the infection group (p = 0.04), and the duration of fever was shorter in the non-pathologic fever group than in the infection group (p = 0.01). Higher procalcitonin levels were observed at POD 5 in the infection group than in the non-pathologic fever group. (p < 0.01) The accidental dural rupture rate was higher in the infected group (p = 0.02); this was thought to be caused by the long non-ambulatory period after surgery. CONCLUSION: This study identified risk factors and differences between infectious diseases associated with postoperative fever. A significant risk factor for postoperative non-pathological fever was a shorter catheter drainage period. Fever after 3 days, fever for more than 4 days and higher procalcitonin levels after surgery suggest infection.