Evidence-Based Surgery

The practice of surgery dependent on the use of well-established research methods and recognized proven techniques, preferably derived from randomized clinical studies or systematic analyses.

Surgery, like many other medical disciplines, has evolved by building personal experience upon personal experience. The knowledge was anecdotal and established through individual cases. Observation represented the most valuable ally under these conditions, and new advances were incorporated with a clear vision of modifying the pathophysiology encountered. Examples of this evolving system included most of the surgical procedures we know today, such as hernia repair, appendectomy, small bowel obstruction treatment, cancer surgery, organ transplantation, and cardiac surgery. These techniques offered extraordinary results and did not necessarily come from the system now called evidence-based surgery. How did this happen? Is it possible that evidence-based surgery is just a new name for the same system we have always utilized? Can we continue practicing surgery as we have always done with good results and not mention evidence-based surgery?

For five years (1999–2004), while teaching the 18-hour annual course called “Critical Analysis/Analytical Medicine” (based entirely on the teachings of evidence-based medicine as proposed by Sackett and his group [[1]]) at Michigan State University College of Human Medicine in Kalamazoo, I initially thought that evidence-based medicine was not a new system. Indeed, I believed it to be the same system utilized since the ancient times of Hippocrates and the Greek natural school of medicine, continued by the great physicians Galen, Avicenna, Harvey, and many others into our present era. I could not believe, much less understand, how we had been practicing medicine and surgery for thousands of years—before evidence-based medicine debuted in 1992 [[1], [2], [3]]—incorporating progress, innovative knowledge, and new ways of treatment, supposedly without using evidence-based medicine and surgery. To me, this created an incongruency that was difficult to accept!

During my surgical residency at the University of Minnesota (1970–1976), I felt that science and research were at the forefront of our surgical activities, though without the name of evidence-based surgery. Other institutions of higher learning also had similar approaches to surgery without using the specific description of evidence-based. Years after the term was coined (1992), surgeons continued to make incredible discoveries based on a traditional understanding of science, research, and clinical experience. Where was evidence-based surgery then? And is it needed now?

It was not until I began teaching “Critical Analysis/Analytical Medicine” again this year (2005) that I started to understand the enormous value that evidence-based medicine or surgery supplies. I guess it took me five years of study and teaching to better understand this approach to education. This special system's roots finally revealed its potential to me. I am a complete believer now and let me tell you why. Evidence-based surgery brought with it the application of systematic research to the traditional practice of surgery. It elevated the means by which a surgeon, an evidence-based surgeon, practices surgery and interprets and evaluates the literature to apply it ideally, that is with the understanding that statistics and study design enter into the final assessment of the patient or study results. According to evidence-based principles, the surgeon should always ask three questions: Are the results valid? What are the results? and Are the results applicable to my patient? [[1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12]].

If David Sackett, distinguished clinician working until recently at McMaster University in Hamilton, Ontario, is considered the father of evidence-based medicine, certainly Archie Cochrane (1909–1988), noted British epidemiologist, should be considered the grandfather of this exciting medical movement. Cochrane was a dedicated proponent of randomized clinical trials, because he believed in their ability to provide the best clinical evidence when no one else was much interested. In 1972, he published his monumental work, Effectiveness and Efficiency: Random Reflections on Health Services [[13], [14]]. In it he strongly supported the utilization of randomized trials to improve results and to test interventions. Even though the first randomized clinical trials came out in 1948 testing the role of streptomycin in treating tuberculosis, clinical epidemiology using randomized trials did not take hold until after Cochrane's book was published in 1972 [[13], [14], [15], [16]]. In recognition of Cochrane's pioneering contributions to evidence-based medicine, Oxford University opened the first Cochrane Center in 1992, and a year later began the Cochrane Collaboration with other centers around the world [[17], [18], [19]].

Cochrane set the stage for Sackett and his group, who helped the surgical disciplines to accept evidence-based medicine as the basis for treatment and practice. Surgeons, encouraged by Cochrane's and Sackett's principles, addressed many key questions: How can we apply evidence-based medicine in a practical manner? What process allows us to implement evidence-based medicine effectively? What is evidence-based surgery? How can we qualify the evidence? How can we categorize the recommendations?

A definition of evidence-based surgery is extremely important, and it has already been presented at the beginning of this paper. Let us add the definition given by the Centre for Evidence-Based Medicine: “Evidence-based medicine is the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients” [[20], [21]]. The surgical ideal is making the best surgical decisions possible based on the gathering of the best evidence currently available. In order to reach this ideal, surgeons must access the literature that provides them with relevant information.

• First, identify the topic

• Second, go to the Cochrane database and systematic reviews.

• Third, proceed to Pubmed/Medline.

• Fourth, advance to e-Medicine and Clinical Evidence.

These steps facilitate an exhaustive review that permits you to ascertain, without a doubt, the real and current status of the medical literature. The most updated and extensive database is Pubmed/Medline. The most carefully evaluated database for evidence-based medicine is the Cochrane database.

In order to characterize the type of evidence, we need to stratify the evidence qualitatively. In this regard, the U.S. Preventative Services Task Force has delineated five levels of evidence by defining the studies from which the clinical data emanated [[10]]. Level I is the highest evidence obtained from at least one randomized controlled trial. Level II-1 is the next in importance, with evidence gathered from a well-designed controlled trial without randomization; level II-2 is evidence obtained from well-designed cohort or case-control studies, preferably from several centers; level II-3 is evidence accumulated from multiple time series with or without intervention. Finally, level III, very anecdotal, is based in opinions of respected authorities, clinical experience, or reports of expert committees. This grading system, as good as it is, is not perfect since the relevance of measurements, the results of the study, and the baseline risk of the effect are not always included [[10]].

Another concern is the categorization of recommendations based on the level of evidence. The U.S. Preventative Service Task Force has defined three levels: level A, where the recommendations are based on good and consistent scientific evidence; level B, where the recommendations are based on limited or inconsistent scientific evidence; and level C, where the recommendations are based primarily on consensus and expert opinion [[10]]. With this information, we can effectively categorize the level of evidence with the appropriate recommendations by strictly relying on the findings.

Robin McLeod presented an excellent review of evidence-based surgery from the surgeon's viewpoint in particular [[9]]. She discussed all elements of evidence-based medicine and surgery and reviewed issues of increasing importance for the practicing surgeon [[9]]. Issues of special concern for surgical trials were the standardization of the procedure and the surgeon's experience and ability to do the surgery. All aspects of perioperative and postoperative care should be standardized as well. One more point would be the performance of blind studies or sham operations which would be ethically difficult to justify in surgical trials today. Surgeons, then, should be aware of all of the various details in the practice of evidence-based surgery [[22], [23], [24], [25], [26], [27], [28], [29]].

Before concluding, I should mention some statistics pertaining to evidence-based medicine. Around 9,000 randomized controlled trials and over two million articles in 10,000 medical journals are published every year [[30]]. This reflects the incredible and difficult task facing practicing physicians and surgeons who wish to keep up with this continuous and ever-increasing body of evidence. For example, an internist would have to read approximately 19 articles each day to stay current [[30]]. General surgeons would probably be required to review a similar number of papers daily to remain well informed. The impossibility of carrying out this awesome task requires that surgical decisions today be based frequently on personal expertise, the weakest form of evidence. In spite of the constraints and limitations of today's busy clinical work, future surgeons must learn to efficiently practice evidence-based surgery so that they can use the strongest form of evidence, the evidence based on scientific findings and well-established clinical trials.

How can evidence-based surgery be taught at the highest level of efficiency without seriously curtailing the surgeon's current activities? I believe it can be done by incorporating the principles of evidence-based medicine into surgeons' daily rounds, operating room functions, postoperative treatment, and office practice. Only by integrating evidence-based principles into practice can we make our task simpler and the results worthwhile. When everyone practices evidence-based surgery, our ultimate objective of better patient care will be fully accomplished. We are looking forward to this day in the not too distant future.