Researchers Change Practice; Selection Bias Could Explain Results; Proper Technique Key
Surgeons speaking at the 2017 annual meeting of the Americas Hernia Society questioned the value of perioperative epidural analgesia in patients undergoing ventral hernia repair after results from a new analysis suggested epidurals may contribute to longer hospital length of stay without any obvious benefit.
A second analysis that used the same database showed transverse abdominis plane (TAP) blocks, which can be an alternative to epidurals, appear to markedly lessen hospital length of stay (LOS) in patients who undergo open repair of large ventral hernias.
“These findings should encourage us to look at and examine some of our foregone conclusions about epidurals. It allows us to take pause and say, ‘Maybe epidurals are not the best thing for every patient,’” said Ajita Prabhu, MD, a surgeon at the Cleveland Clinic and author of one of the studies.
“There is no benefit to epidurals in terms of length of stay. Patients did not have a shorter hospital length of stay related to epidurals, which has previously been described as one of the potential benefits of using them in other patient populations.”
Both studies used data from the Americas Hernia Society Quality Collaborative (AHSQC), a national quality improvement effort that collects and analyzes data from more than 200 American surgeons. Founded in 2013, AHSQC has grown to include information on more than 15,400 hernia operations.
Dr. Prabhu and her colleagues examined the effects of epidural analgesia in patients who underwent open, clean, elective ventral hernia repair without TAP blocks. The patients were separated into two comparable groups matched on several confounding factors using a propensity score algorithm: One group received postoperative epidural analgesia (n=763) and the other did not (n=763).
Patients receiving epidural analgesia had a half-day longer hospital LOS (5.49 vs. 4.90 days; P<0.05), a higher risk for any postoperative complication (26% vs. 21%; P<0.05), and worse pain intensity scale scores (47.6 vs. 44.0; P=0.04). The risk for wound events was similar between the two groups.
The investigators also analyzed patient-reported outcomes, using responses to the HerQLes hernia quality-of life survey (100 in the epidural group; 66 in the nonepidural group) and the PROMIS Pain Intensity 3a questionnaire (94 in the epidural group; 55 in the nonepidural group). Again, patients who received an epidural reported higher pain scores.
However, it is unclear whether this reflects a patient selection bias. “It may be that we are selecting the patents who have more complex hernia disease for epidurals,” Dr. Prabhu said.
Even so, Dr. Prabhu and her colleagues have changed their practice at the Cleveland Clinic based on the results of the study. They do not use epidurals routinely but work with anesthesia to develop regimens that may include ketamine drips, TAP blocks or epidurals. “We’ll see how it continues to evolve. If we have a different finding at a different time, we’ll use that data to change our practice accordingly.”
She added that there is likely a population of patients who are appropriate candidates for epidurals, but this group was not identified in this analysis.
The full study was published in the Annals of Surgery ([Epub Mar 10, 2017]. doi: 10.1097/SLA.0000000000002214).
Other data from the AHSQC indicate that TAP blocks may reduce hospital LOS without increasing patient pain.
Jeff Blatnik, MD, a hernia surgeon at Washington University School of Medicine in St. Louis, examined outcomes for 252 patients who received TAP blocks and 504 who did not during open repair of complex ventral hernias. Patient characteristics—age, sex, and rates of diabetes, chronic obstructive pulmonary disease and smoking—were similar in the two groups. All patients had hernias greater than 100 cm2. The analysis excluded all patients who underwent an epidural.
Patients who had a TAP block remained in the hospital for 5.6 days, nearly two days less than patients who did not receive a TAP block. Rates of surgical site infections, surgical site occurrences and patient-reported outcomes appear to be unaffected by receipt of TAP blocks.
Dr. Blatnik said TAP blocks are a regular part of his practice but stressed the data in the AHSQC are limited. The database does not account for the use of enhanced recovery after surgery pathways, which are likely to influence hospital LOS. Moreover, the study could not compare TAP blocks against other regional anesthesia or epidurals.
“But I think the takeaway is that TAP blocks are low cost: A standard 60 cc of bupivacaine is incredibly cheap. It doesn’t take much time to perform and adds a relatively low morbidity.”
He surveyed 20 surgeons who are members of the AHSQC and routinely perform TAP blocks. They reported a mix of approaches: Half said they do TAP blocks themselves, mostly intraoperatively before closure; and half had anesthesia perform TAP blocks, often preoperatively. Three-fourths of surgeons said they use bupivacaine; the remainder use liposomal bupivacaine.
In the discussion following the presentations, several surgeons cautioned against moving too quickly away from epidurals. The data collected by AHSQC are observational. The data do not track important variables such as how epidurals are used, nor do they provide a way to assess technical proficiency with epidurals or TAP blocks. These things affect patient outcomes, they said.
“For hernias, we all do things different and they are technique dependent. This, to me, is so operator dependent that it’s going to be really hard. We all do it differently, use a number of different agents, put in different amounts,” said William Hope, MD, immediate past president of the AHS and a surgeon at New Hanover Regional Medical Center, in Wilmington, N.C.
Michael Rosen, MD, medical director of the AHSQC and director of the Cleveland Clinic’s Hernia Center, said surgeons should use the AHSQC to examine their own results and, if needed, reevaluate their pain control protocols.
“What some of this data does show is clearly a downside of epidurals, but we know there’s clearly a benefit of a well-functioning epidural. We need to keep looking at pain control with real data and figure out what we should be doing, what’s causing harm and what’s an advantage.”