Medical Student Geisinger Commonwealth School of Medicine
Disclosure(s):
Erin Welby, MS: No financial relationships to disclose
Introduction: Intraoperative hypothermia (T < 36°C) has been well established to increase surgical complications, blood loss, and need for transfusion in orthopaedic arthroplasty literature. There is limited data investigating the perioperative effects of hypothermia in spine surgery. The purpose of this study was to (1) compare the demographics of lumbar fusion patients who did and did not develop complications, and (2) characterize the effects of intraoperative hypothermia on blood loss and postoperative complications.
Methods: Retrospective analysis was performed identifying adult patients undergoing elective posterior lumbar fusion for degenerative pathology from 2022 to 2024. Patient demographics, intraoperative blood loss, perioperative temperature records and postoperative complications were collected. Descriptive and inferential statistics were performed.
Results: A total of 293 patients were collected, of which 35 (11.9%) developed a postoperative complication (Comp) and 258 (88.0%) had uneventful recoveries (No-Comp).
Demographic analysis demonstrated the Comp cohort had higher ASA scores (2.77 vs. 2.59, p=0.019), higher Charlson Comorbidity Index scores (3.1 vs. 2.2, p=0.009), and greater number of fusion levels (2.2 vs. 1.7, p=0.017). No cohort differences were found for patient BMI, age, ethnicity, and smoking status.
Cohort analysis demonstrated no difference in intraoperative hypothermic time (Comp: 94.3min, No-Comp: 96.3min, p=0.897), temperature fluctuation (Comp: 1.0°C, No-Comp: 1.2°C, p=0.132), mean temperature (Comp: 36.0°C, No-Comp: 36.0°C, p=0.965), length of surgery (Comp: 209.0min, No-Comp: 206.2, p=0.857), and estimated blood loss (Comp: 431.0ml, No-Comp: 340.1ml, p=0.182).
On univariate and multivariate analysis, EBL and complications were influenced by number of fusion levels but not by hypothermic time (p < 0.05). Each additional fusion level corresponded to a 65.8ml increase in blood loss and 1.39 times the odds of complications.
Conclusion : Intraoperative hypothermia does not influence postoperative complications or blood loss following posterior lumbar fusion, going against previous published literature in non-spinal orthopaedic subspecialties. Each additional fusion level corresponded to a 65.8ml increase in blood loss and 1.39 times the odds of complications.