I use mechanical bowel preparation (MBP) for colorectal surgery since the beginning of my general surgery residency (2006). As far as I know, this was the common strategy in most worldwide surgery departments. Since the only proven factor to reduce surgical site infection (SSI) is a 24h systemic antibiotic prophylaxis, this has also been my practice till today.
Although based on low-quality science, the emergence of the ERAS program was responsible for MBP increasing abandonment. Thankfully the world keeps rolling. Today, papers are questioning that (bad?) decision.
A paper published in January 2022 in BJS pretends to summarize in 5 questions all we must know about bowel decontamination before colorectal surgery. I strongly advise you to read the entire paper.
The first idea that comes out from this work is that antibiotics plus MBP reduce SSI after colorectal surgery. The second idea I took from the paper is the possible reduction in anastomotic leakage when using that bowel preparation. No valid data conclude that it reduces, increases, or has no effect on anastomotic leakage. The third idea is the importance of the gut microbiome in colorectal surgery complications.
According to the authors, the present-day evidence supports some recommendations. For elective colon resection, the use of oral plus intravenous antibiotics reduces postoperative SSI and reduces overall complications. The reduction of anastomotic leakage is unclear in colon surgery. For elective rectal resection, surgery recommendations advise antibiotics plus MBP to reduce SSI. That association possibly reduces anastomotic leakage, makes on-table colonoscopy possible, and eventually reduces the postoperative ileus. In urgent colorectal surgery, a colonic stent allows for appropriate bowel preparation. Additionally, preoperative enemas have no benefit. The intraoperative washout technique seems to do not give any advantage.
The problem of MBP is the possible side effects. It can cause abdominal pain, nausea and vomiting, and dehydration. Therefore, the authors advise a patient-tailored approach. MBP can be omitted if expected side-effects overwhelm the benefits. Selective decontamination of the bowel has no differences in anastomotic leakage but decreases SSI.
Summarizing in three ideas:
Oral plus intravenous antibiotics in colorectal surgery reduce SSI. Although possible, its role in anastomotic leakage reduction is a matter of debate.
MBP is currently used in rectal surgery to reduce SSI.
MBP without antibiotics is of questionable value.
One interesting issue the authors talk about is the microbiome and its impact on the future of bowel preparation. The microbiome can influence well-being and can affect anastomosis healing. So, manipulation of the microbiome and the MBP can be both useful. The future seems to be a patient's-tailored bowel preparation to manipulate specific strains rather than a one-fits-all bowel preparation strategy. It means that a patient's microbiome will be characterized before preoperative and postoperative manipulation.
Once again, tailored medicine is the future. Once again, doing the same procedure and doing it the same way for every patient is not the best practice.
Link to PubMed:
Dr. Carlos Eduardo Costa Almeida
General Surgeon