Author: Bob Kronemyer
Among choices of neuraxial anesthesia for patients undergoing total hip and knee arthroplasty, spinal anesthesia provides the best postoperative outcomes, according to a large retrospective cohort study.
Compared with combined spinal and epidural (CSE) anesthesia, spinal anesthesia significantly reduced the likelihood of cardiac, pulmonary, gastrointestinal and thromboembolic complications by between roughly one-third (cardiac) and two-thirds (thromboembolic).
Prolonged hospital length of stay also was reduced by 28% compared with CSE.
However, patients who received epidural anesthesia had about the same complication rates as patients receiving CSE.
Which Neuraxial Approach Is Best?
“In the last few years, our group and others have performed a number of population-based studies suggesting that neuraxial anesthesia is associated with better perioperative outcomes when compared to general anesthesia in hip and knee arthroplasty patients,” said principal investigator Stavros Memtsoudis, MD, PhD, MBA, a professor of anesthesiology and public policy and research at Weill Cornell Medical College, in New York City. “However, because of the limitation of our data sources, we were not able to determine if it was truly the neuraxial anesthetic that made the difference or if it was simply a surrogate marker for a specific type of care provided by certain hospitals that happened to provide neuraxial anesthesia.”
The investigators also did not know whether there was a difference between the types of neuraxial techniques for outcomes. “That is why we used data from a hospital, which has a high rate of standardization of care, as well as a high rate of neuraxial use,” Dr. Memtsoudis said.
Of the cohort, a total of 40,852 patients (20,613 hip and 20,239 knee) received neuraxial anesthesia: 34,301 CSE, 2,464 epidural and 4,087 spinal.
The remaining 914 patients (2.19%) in the cohort received general anesthesia and thus were excluded from the primary analysis, but were included for sensitivity analysis.
“Observing that even in such a controlled setting neuraxial [anesthesia] was associated with better outcomes was a validation of our previous assumptions,” Dr. Memtsoudis said. “Further, identifying spinal anesthesia to be the preferred approach was important because other techniques, like combined spinal and epidurals, were more frequently used.”
Dr. Memtsoudis said the study offers a more nuanced understanding of anesthesia technique as a modifiable risk factor for adverse postoperative outcomes after total hip and knee arthroplasty. “Our results certainly provide the basis for some real practice changes,” he said.
Employing neuraxial versus general anesthesia appears to be increasingly supported by the literature, Dr. Memtsoudis added. “With this growing evidence, and in the absence of data suggesting that neuraxial is worse than general, the results of our study promote the transition from a practice that currently is still largely dominated by a general anesthetic approach in joint arthroplasties in the United States,” he said.
Nonetheless, while the evidence using population-based data is growing in favor of neuraxial anesthesia, “mechanistic studies are needed to add certainty,” Dr. Memtsoudis said. “Moving evidence that is based on association to that based on causation between intervention and outcome is still required.”
Rationale for Choosing Neuraxial Types
F. Kayser Enneking, MD, a professor of anesthesiology and orthopedic surgery at the University of Florida, in Gainesville, was surprised that the study showed such a difference in complication rates between the spinal and CSE groups.
“Clearly, the preferred practice at the study’s institution is CSE, since this was the overwhelming choice in this non-randomized look back at their practice pattern,” Dr. Enneking said. “Generally, CSE is performed when the surgery end time is less definite or in instances when the epidural can be used to provide prolonged analgesia in the postoperative period.”
Hence, the rationale for choosing spinal over CSE may have influenced this difference in outcome, according to Dr. Enneking. “Either the cases were anticipated or were actually longer in the CSE group, or perhaps the use of epidural following surgery for analgesia may have had an influence on the complication rate,” she said.
Regardless, Dr. Enneking believes neuraxial anesthesia is an excellent choice for many patients undergoing lower extremity arthroplasty and should, in her opinion, be the technique of choice. “Because of its simplicity and long safety record, spinal anesthesia has always been my preferred technique,” she said.
Dr. Enneking said it is gratifying that neuraxial techniques are being recognized as the method of choice, to the point where differences between types of neuraxial anesthesia are being discerned. “Continued examination of all the factors that are relevant between these techniques should be encouraged,” she said.