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Overlapping Surgery Largely Safe

Surgical outcomes seem as good whether the primary surgeon is involved in more than one case simultaneously or not, a large study showed.

However, there were signals of greater risk in overlapping surgery for cardiac bypass and in higher risk cases, Anupam Jena, MD, PhD, of Harvard, and colleagues reported in JAMA.

Across seven common surgeries — total knee or hip arthroplasty; lumbar, thoracic, or cervical spine surgery; coronary artery bypass graft (CABG) surgery; and craniotomy — for which the primary surgeon had two or more operations running simultaneously for at least an hour of longer procedures, or the entire procedure if duration was less than an hour, the findings were:

  • A similar unadjusted mortality rate of 2.1% vs 1.6% for nonoverlapping surgeries (P=0.11)
  • Equivalent in-hospital mortality adjusted for surgeon-procedure fixed effects and patient characteristics (1.9% vs 1.6%, P=0.21)
  • No difference in the unadjusted complication rate (14.0% vs 11.7%, P=0.10)
  • Similar adjusted postoperative complication rates (12.8% vs 11.8%, P=0.08)

Overlapping surgeries were longer in both unadjusted (237 vs 169 min, P<0.001) and adjusted (204 vs 173 min, P<0.001) analyses and for every subgroup.

“This study strengthens the evidence that overlapping surgery is a reasonable practice for many cases,” the researchers concluded.

That is good news for the current system of surgical education, Edward Livingston, MD, wrote in an accompanying editor’s note as deputy editor of the journal.

“This work appealed to me because it answered an important, unresolved question: Is surgery safe as practiced in academic environments that balance the needs of safe patient care with those required to train the next generation of surgeons? The answer appears to be yes.”

A prespecified, exploratory analysis looked specifically at CABG surgery and found overlap associated with both greater in-hospital mortality (4.0% vs 2.2%, P=0.009) and more complications (34.5% vs 30.2%, P=0.007).

While neither interaction of outcome by overlap was significant across surgery types (mortality P=0.08 and complications P=0.09 for F test), they were nearly so, noted John Alexander, MD, MHS, director of cardiovascular research at the Duke Clinical Research Institute in Durham, North Carolina.

“Interaction tests are not terribly sensitive,” he told MedPage Today. “Some say they are insensitive enough that we should probably use 0.1” as the threshold for significance.

“The signal in CABG should leave it as being an open question in that it deserves further study,” he concluded.

Thoralf Sundt, MD, chief of cardiac surgery at Massachusetts General Hospital in Boston, agreed: “It should be taken seriously, but I don’t think it’s definitive enough to change practice because I can so easily imagine reasons why an association like this could exist without causality.”

The other prespecified subgroup analysis also turned up higher risk from surgical overlap: High-risk patients saw increased mortality (5.8% vs 4.7%) and more complications (29.2% vs 27.0%), which were both significant compared with nonoverlapping procedures and compared with low-risk patients in a test of interactions.

This signal makes intuitive sense, Livingston noted.

Overall, 12% of the 66,430 operations were overlapping in the Multicenter Perioperative Outcomes Group electronic health record registry of all procedures requiring anesthesia across more than 50 hospitals in 18 U.S. states and the Netherlands.

Among the 207 surgeons included, 73% performed overlapping procedures, with an average 12% of their procedures overlapping.

“A unique aspect of the study was that the data included all of a surgeon’s cases during the study period, allowing for an analytic design that helped to minimize confounding by comparing a given surgeon’s overlapping and nonoverlapping cases of the same type,” the researchers noted.

One limitation of the electronic health record study was that it didn’t address whether the attending surgeon was present during a part of the operation considered critical, Livingston noted.

Defining the critical part of the operation requiring the primary surgeon’s presence “should be determined by an independent body of clinicians familiar with the operating room environment and monitoring to ensure that the attending surgeon is in the operating room during that time,” he wrote.

Another limitation was that administrative data isn’t good at fully assessing comorbidities or frailty, which could be confounding factors, Sundt noted.

The next step to answering the question of overlapping surgical safety in CABG is to look at the Society of Thoracic Surgeons national database, perhaps married to another database with timing data, he suggested.

The study was funded by the National Institutes of Health and the National Institute on Drug Abuse.

Jena reported receiving personal fees from Pfizer, Hill RomServices, Bristol-Myers Squibb, Novartis, Amgen, Eli Lilly, Vertex Pharmaceuticals, AstraZeneca, Tesaro, Sanofi Aventis, Biogen, Precision Health Economics, and Analysis Group, outside the submitted work.

Livingston, Sundt, and Alexander disclosed no relevant relationships with industry.