Nancy A. Melville

April 28, 2017

LOS ANGELES — In the latest study to address public concerns of risks associated with overlapping surgeries, a large analysis of nearly 15,000 neurosurgical procedures shows not only that patient outcomes are no worse with the common practice but that several outcomes are in in fact improved in the setting of overlapping surgeries.

"We found that in every single outcome measure where there was a significant difference between patients who had overlapping surgery and those who didn't, it was in favor of the overlapping surgery group, said first author, Michael Bohl, MD, a neurosurgery resident with the Barrow Neurological Institute, Phoenix, Arizona, presenting the findings here at the American Association of Neurological Surgeons (AANS) 2017 Annual Meeting.

The common practice of overlapping surgeries became the subject of public controversy in 2015 when an article in the Boston Globe raised concerns of risks to patients, resulting in an investigation by the US Senate Finance Committee, which concluded in December 2016 that the data were inadequate to determine whether the practice posed a risk or not.

The controversy prompted numerous institutions to conduct their own analyses, however, including a study published by the Mayo Clinic in the Annals of Surgery, which, like the other studies, showed no risk to patients.

For the current study, Dr Bohl and his colleagues conducted a retrospective analysis of all cases performed between July 2013 and June 2016, dividing the 14,872 cases into groups of procedures that were performed with overlapping of surgeries and those that were not.

Factors considered in the study included patient characteristics, type of procedure, resident year of training, American Society of Anesthesiologists score, severity of illness, risk for death, and the percentage of case overlap.

A univariate analysis showed overlapping surgery cases had a significant benefit in various outcome measures, including terms of hospital length of stay, return to the operating room (OR), and disposition status (all P < .001).

The overlapping cases were significantly longer and staffed by more senior residents (P < .001), and, after adjustment for factors in a multivariate analysis, no significant differences remained in any of the measured outcomes except procedure length.

In a separate subanalysis of patients undergoing aneurysm clipping at the institute, as part of the prospective Barrow Ruptured Aneurysm Trial, 123 patients in overlapping surgeries were compared to 118 in nonoverlapping procedures. The results showed improved aneurysm obliteration rates at hospital discharge in the overlapping surgery group.

And in an additional subanalysis of deep-brain stimulation (DBS) cases at the center, including 141 overlapping and 183 nonoverlapping procedures, no differences were seen in electrode error, brain penetrations, or other general outcome measures, Dr Bohl reported.

"The results show that overlapping surgery affords improved or equivalent outcomes to patients as compared to nonoverlapping surgery," he said.

"This applies to large heterogeneous patient cohorts as well as smaller cohort  and appears to apply to high-risk, highly complex procedures typically performed by chief residents, such as aneurysm clipping, as well as to lower-risk but still technically complex procedures, such as DBS lead placements, typically done by junior residents."

Dr Bohl noted that the evidence negates logical speculation that the overlapping cases somehow may simply have been less complex.

"Our data suggest against that theory, showing the overlapping cases were assigned to residents who were more senior and they also took a significantly longer period of time, both of which suggest against a lesser degree of case complexity in those cases."

"We think a more likely explanation for this is that increased resident involvement in the OR confers an advantage to patient care. For example, having a resident perform the noncritical portions of the case leaves the attending with a fresh mind and fresh hands to perform the critical aspects of the case," he said.

In discussing the strength of the evidence, John R. Kestle, MD, from the Department of Neurosurgery at the University of Utah, Salt Lake City, noted some important limitations of the study, including the nature of the specialized setting.

"This is a highly select population of patients that were treated at a tertiary referral center by experienced neurosurgeons, so we have to be careful about generalizing these results to the neurosurgery community in general," Dr Kestle said.

"The outcomes include length of stay, reoperation, disposition and readmission and appear to be objective and resistant to observer bias. [However], other, more sensitive outcomes were not reported, such as infection rates and neurological deficit."

Robert E. Harbaugh, MD, director of the Neuroscience Institute and Distinguished Professor and chair of the Department of Neurosurgery at Penn State University, Hershey, Pennsylvania, said the findings nevertheless reflect the experiences of many surgeons and surgical teams in efforts to increase efficiency while also working to improve outcomes.

"I think those of us who have been doing surgery and training residents for a long period of time feel there is significant benefit in overlapping surgery, not only to OR efficiency but to graduate medical education," he said in discussing the study.

Dr Harbaugh noted that the guidelines set forth in a position statement

 of the AANS, American Board of Neurological Surgery, Congress of Neurological Surgeons, and Society of Neurological Surgeons help clarify the appropriate procedures for overlapping surgeries.

"The statement clarifies that simultaneous surgeries, with 100% overlap, are of course not appropriate, but if critical elements of one case have been completed, it's perfectly all right to have a resident finish that case as long as the surgeon of record is there for the critical parts of the case, and it's also important that you must inform your patients," he said.

The authors, Dr Kestle, and Dr Harbaugh have disclosed no relevant financial relationships.

American Association of Neurological Surgeons (AANS) 2017 Annual Meeting. Abstract 917. Presented April 26, 2017.

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