A Comparison between General and Neuraxial Anesthesia on the Incidence of Surgical Site Infection Rates Following Total Joint Arthroplasty: A retrospective study at Detroit Medical Center 2011-2015.
Kunal Sood, M., Rishi Sood, BS, Aashish Kumar MD, Dat Duong MD, Gem M. Manalo BS, Evan Albazi BA, Sivanoli Ambalavanan, MD, Ankit Bhatia BSc, Bright Kim BS, Adam Schumaier BS.
Detroit Medical Center (DMC), Detroit, Michigan
Introduction: Prosthetic joint infection occurs following roughly 2% of total knee arthroplasties. It is anticipated that by 2030, total knee arthroplasty procedures performed annually will increase by 673% and total hip arthroplasty procedures will increase by 174%. It is imperative to reduce the burden of SSIs. The first few hours of surgery is a critical period in which surgical wounds are contaminated and surgical site infections can develop. It is vital to establish the optimum surgical and anesthesia techniques during this period to reduce the risk of SSIs. Previous studies have shown that the sympathetic blocking effect of neuraxial anesthesia improves tissue perfusion and oxygenation, which may reduce the risk of SSI. More recent literature has confirmed that total joint arthroplasty under general anesthesia is associated with a higher risk of SSI compared with epidural or spinal anesthesia, finding a rate of SSI of 2.8% with general anesthesia and 1.2% with neuraxial anesthesia.
The Primary study aim is to compare the rate of surgical site infection with neuraxial anesthesia versus general anesthesia in patients undergoing joint (hip and knee) surgery. Secondary aims of the study will be observe is there are factors that increase the risk of rate of SSI in order to identify potential prevention interventions and reported SSI risk factors.
Methods: After institutional review board approval, data for the last 5 years was collected via patient chart records. The following information was collected: Patient demographics, comorbidities, surgery, surgical site infection (SSI defined as an infection that occurs within 90 days of surgery in the part of the body where the surgery took place, including superficial infections involving only the skin), type of anesthesia, operator, anemia, perioperative antibiotics, perioperative normothermia, hyperglycemia, recent infections (within 90 days prior to surgery), perioperative transfusion amounts (cc) and rates, recurring surgery within 90 days of initial surgery.
Results: A total of 46 SSI occurred from a total of 2429 surgeries (1.9%). To analyze potential factors leading to SSIs, the joint surgeries resulting in SSIs (n=46; SSI) were compared to joint surgeries that didn’t result in any SSIs (N= 925; Non SSI). When comparing characteristics of the groups there were no significant differences between Age (Non SSI 59±11.6 yrs: SSI 58.5±10.6 p=0.55), Anesthesia type affected the occurrence of SSI with an approximate threefold increase of SSIs associated with general anesthesia (3.4%) compared with neuraxial anesthesia (1.2%; p=0.12) although this effect was not statistically significant. Gender (p=0.15), anesthesia experience (p=0.38), hemoglobin levels (p=0.52), BMI (p=0.74) and smoking (p=0.36) showed had no significant differences in occurrence between SSI and Non SSI patients.
Conclusion: The observed three fold difference between SSI rates in neuraxial vs general anesthesia with lower SSIs rates associated with neuraxial anesthesia indicates that anesthesia type is potential factor in reducing SSIs. This trend will be further analyzed through additional chart analyses (additional n=1500) to increase the power of the study and limit the probability of type 2 errors due to small sample size.