The role of anesthesia as a potential modifier of postoperative outcome has been subject of scientific discussion for several decades. This notion has particularly spurred comparative effectiveness research on the perioperative impact of neuraxial anesthesia as an alternative or adjunct to general anesthesia. As data exist on a population level, we sought to study this issue in the context of a large specialty practice focusing on regional anesthesia. Our hypothesis was that neuraxial anesthesia would be associated with reduced postoperative complications compared to general anesthesia.
We utilized institutional, administrative data from the Hospital for Special Surgery (HSS), to extract cases of total knee arthroplasties (TKA) between 2005 and 2014. The study protocol was approved by the Institutional Review Board of HSS. Patients, characteristics, diagnoses, and provided procedures were identified by ICD-9 codes, and standardized billing items. Patients whose initial anesthesia billing transaction did not occur until after their date of admission (n=73) and those whose primary type of anesthesia was missing (n=901) were excluded.
Outcomes of interest included in-hospital events of cardiac, respiratory, gastrointestinal, genitourinary, wound and surgical site complications, thrombosis, falls and length of stay (LOS). A multivariable logistic regression model was used to compute odds ratios (OR), corresponding 95% confidence intervals (CI) and p-values. Covariates included were age, gender, anesthesia technique, meaning general and neuraxial anesthesia (epidural, spinal or combined spinal-epidural (CSE)), and comorbidities by the Deyo comorbidity index.
After applying exclusion criteria, the resulting dataset consisted of 21,205 patients. Analysis showed that the odds for cardiac complications were significantly reduced in CSE or epidural anesthesia compared to general anesthesia (OR 0.66 [CI 0.49-0.89]; OR 0.56 [CI 0.35-0.90]; p<0.05 respectively), however this trend did not reach statistical significance in spinal anesthesia. Moreover, spinal versus general anesthesia was associated with significantly decreased odds for respiratory complications (OR 0.33 [CI 0.19-0.57]; p<0.05). Wound and surgical site infectious complications were significantly decreased when CSE or spinal anesthesia was utilized compared to general anesthesia (OR 0.39 [CI 0.18-0.81]; OR 0.13 [CI 0.04-0.42]; p<0.05 respectively). Furthermore, genitourinary complications were significantly reduced when CSE anesthesia was given instead of general anesthesia (OR 0.44 [CI 0.27-0.72]; p<0.05). No significant differences by anesthesia technique were found for gastrointestinal, and thromboembolic complications or falls. However, spinal as well as CSE anesthesia were associated with decreased odds for prolonged LOS, defined as the highest quartile of hospital of stay.
In summary, the utilization of neuraxial anesthesia was associated with a significant decrease in postoperative adverse events, including cardiac, respiratory, genitourinary, wound and surgical site complications as well as a shorter LOS among TKA patients receiving care in a specialty surgical setting. These results are in line with other population based studies, that similarly suggest improved outcome with neuraxial anesthesia. However, more research is needed to achieve conclusive evidence and identify the magnitude of a potential benefit, particularly as some studies have failed to confirm these benefits.