The Blame Game: Is Wound Infection Due To Patient Risk Factors Or Surgical Technique?

Editor’s Comment: I’d like to welcome back Dr. Goldfarb for another guest post, this time to weigh oft-cited “patient factors” against surgical technique as risk factors for the development of SSI.

Who should be blamed for a wound infection after colon surgery? Was it the patient’s fault because of the patient’s condition creating “risk factors,” or was it the surgical technique?  In my opinion the definitive answer is, “It depends.”

Patient risk factors such as, type of bowel preparation, pre-operative antibiotic choice, pre-operative steroids, diabetes control, abdominal preparation, and intraperitoneal contamination from disease,  have been blamed. Technical operative issues including length of surgery, intra –operative hypotension, wound hematoma, management of contaminated wound, glove changes, technique of anastomosis, and technique of abdominal wound closure are also culprits.

A study by Kosuke Ishikawa, “Incisional Surgical Site Infection after Elective Open Surgery for Colorectal Cancer,” was published in the International Journal of Surgical Oncology (Volume 2014).  He analyzed 33 (14.7%) infections in 224 patients who had surgery in 2009. He used mechanical bowel preparation with an oral cathartic, IV antibiotics, povidone scrub, the Alexis wound protector immediately after making the incision, stapled anastomoses, 2L peritoneal saline lavage irrigation of subcutaneous fat with 400cc saline after closure of the fascia, and a subcutaneous drain. For years, some of those measures have been controversial. Several of those efforts were trying to limit or treat the contamination of wounds.

The median time to the identification of incisional SSI was nine days. “By univariate analysis SSIs were more likely to have a higher ASA scores and TNM stage. When evaluating the perioperative/operative variables, length of incisional site and intraoperative hypotension were associated with the development of incisional SSI.” In this study, therefore, statistics revealed that SSI could be blamed on both patient risk factors as well as surgical technique.

Another article, “Surgical Site Infection in Colon Surgery,” by Martin Hubner (JAMA November 2011, Vol 146, no 11), is particularly relevant in the blame game.

He studied 2394 patients who underwent colon surgery between March 1, 1998 and December 31, 2008. There were 428 (17.9%) SSIs and individual surgeon’ rates varied from 3.7% to 36.1%. No correlation was found between surgeons’ individual adjusted risks and their adherence to guidelines or their experience.

“Features of the patients and procedures associated with SSIs in univariate analysis were male sex, age, American Society of Anesthesiologists score, contamination class, operation duration, and emergency procedure.   Correctly timed antibiotic prophylaxis and laparascopic approach were protective.”

“Procedure-related risk factors include antibiotic prophylaxis, oxygen supply, fluid management, bowel preparation, and skin disinfection. Arguably, the surgeon constitutes the single most important risk or protective factor for SSI.” The adherence to guidelines, detailed below, has subsequently been questioned since the recommended guidelines have not been able to lower the rate of wound infections.

In the comment section, Huber states that, “A recent retrospective cohort study of 405,720 surgical patients from 398 US hospitals (3996) could not demonstrate that adherence to any of the 6 infection prevention process of care measures from the Surgical Care Improvement Project protocol, including adequate antibiotic prophylaxis (timing, drug, duration), glucose control of cardiac surgery patients, adequate hair removal and postoperative normothermia for colorectal surgery patients)could reduce the risk of SSI.”

I think after colon surgery, sometimes patient risk factors may be contributory and can be responsible for SSIs. But surgical technique is probably to blame for most SSIs, after elective surgery. Efforts to minimize wound contamination especially in elective surgery, may be the most important factor under the surgeon’s control. I remember someone saying to me, “I didn’t say you were wrong, I said I was going to blame you.”

Surgical Infection in the Age of Minimally-Invasive Surgery

Today marks about 4 years since Prescient Surgical was founded, conveniently marked by the company’s incorporation in the fine state of Delaware. After a full year of exploring various unmet needs in hyperkalemia to Raynaud’s phenomenon as Innovation Fellows in the Stanford Biodesign program, the founding team began to rally around what we called “The SSI Project.” With strong support from the surgical community at Stanford and beyond, and under full sail with the trade winds of public reporting and fines implemented with the Affordable Care Act, it was clear we were chasing down a critical unsolved problem in surgery that required immediate attention.

Naturally, I remain convinced of that fact today, and am thrilled by the progress we’ve made as a company and community towards reducing surgical site infection. Yet from the moment we began this journey, the requisite gauntlet of venture capitalists, health systems, BigCo’s, and physician interaction have buffeted us with a recurring, unseemly paradox that I’d like to address here—mainly, that the evolution of minimally invasive surgical techniques (predominantly laparoscopic surgery) has all but eliminated SSI.

Well…so why do we still see so many infections? Is it because laparoscopic / MIS techniques are in fact a panacea, but have not yet been fully adopted? Probably not, and for the past 5 years at ASCRS we’ve seen laparoscopic adoption in colorectal surgery stagnate at around 30-40%, even as the video game generation enters its prime. Laparoscopic techniques simply aren’t or can’t be used in the majority of some of the most complex surgeries.

In my position I am privileged with access to some of the world’s greatest minds in surgery, and I’m hearing a consistent belief that the next decade of surgical development will be about OR safety, not necessarily OR “MIS-ness.” One prominent single-port laparoscopic surgeon put it this way—“The impact in cholecystectomy was enormous, but when you look at more complex procedures like colectomy, you are taking out a colon, you are extracorporealizing a contaminated specimen. It’s fundamentally invasive, and within that big-picture context, MIS techniques offer real, but comparatively diminished benefits.” He advocates MIS “right-sizing,” that is mitigating patient risk in ways that might include laparoscopy when appropriate as opposed to the uncompromising pursuit of a near-incisionless nirvana. I was surprised to hear this from a surgeon that could perform a single-port colectomy wth one hand tied behind his back! It’s all about striking a balance between the risk and global invasiveness of each surgery with the each surgeon’s ability to perform it effectively and efficiently.

Is it because there are large financial interests that would like you to believe that the increased costs of laparoscopic surgery are justified by unilateral improvements in surgical care? Perhaps. I would never question the net benefit of laparoscopic approaches, but particularly when it comes to SSI, the data are mixed, and high SSI rates persist.

Consider Covidien / Medtronic’s clinical dossier summarizing the benefits of laparoscopic approaches in colorectal surgery (http://www.medtronic.com/content/dam/covidien/library/us/en/clinical-procedural-therapy/colorectal/colorectal-global-value-dossier.pdf):

“Surgical Site Infection: Rates of surgical site infection are consistently lower (often significantly) with laparoscopic colorectal surgery than open colorectal Surgery.”

Covidien data

By “often significantly,” Medtronic means that studies do not always show this benefit with statistical significance, and at times have been associated with higher infection rates in colon surgery. Though the weight of evidence supports the notion that laparoscopic approaches reduce the risk of SSI, there are still infections in laparoscopic surgery (perhaps 4-17% based on the data presented by Medtronic, though the most recent studies, and NSQIP rates at high-volume laparoscopic centers would suggest rates of 7-12%, and prospective studies generally find rates of 15-20%+). We shouldn’t be surprised either. However small, the resulting incisions are still prone to intraoperative contamination and reduced immunological activity. Even with laparoscopic approaches, a comprehensive wound care plan is warranted.