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After removal of a section of cancerous bowel the ends need to be stitched back together. In endoscopic (keyhole) surgery this is usually done by pulling both ends out through a small hole in the skin and stitching them outside the body, before pushing the joined bowel back inside. This is called extracorporeal anastamosis.

Alternatively stitching the bowel inside the body, intracorporeal anastomosis, may reduce the risk of damage, but is technically demanding.

This review found that stitching the bowel inside, rather than outside the body did not increase the risk of death or complications and reduced infection rates, length of hospital stay and the time it took for bowels to start working again.

The findings are based on observational studies and require confirmation in randomised controlled trials. Implementation issues, such as training requirements, should be investigated before this approach is widely implemented.

Why was this study needed?

Bowel cancer is the third most common cancer in the UK, accounting for 12% of cancer cases and 10% of cancer deaths each year. Six out of ten people with bowel cancer will require surgery to remove the cancerous part of their bowel and stitch it back together. Extracorporeal anastomosis may need larger incisions to allow the surgeon to pull the bowel out of the body, and may carry a greater risk of damaging the bowel tissues leading to more ileus (slow bowel function). Intracorporeal anastomosis requires smaller incisions, but is a highly skilled procedure with a greater risk of faecal matter leaking into the abdomen during stitching.

This systematic review set out to compare complication rates in studies of intracorporeal and extracorporeal anastomosis.

What did this study do?

Twelve observational studies, a total of 1492 patients who had the right side of their large bowel removed during endoscopic surgery, were included in the review which compared studies of extracorporeal anastomosis with intracorporeal anastomosis. The main outcomes were mortality, morbidity (illness) and length of hospital stay.

Because people were not randomly allocated to treatment, patient characteristics may have influenced the surgeon’s choice of operation, for example how advanced the cancer was. Additionally 11 out of the 12 studies were retrospective, meaning they looked back at the outcomes of people who had received the different surgeries, rather than prospectively following them from the outset. Retrospective studies tend to be less reliable because they may not have collected all relevant data on patient and operative factors that could be having an influence.

Adverse events were generally rare across the studies. The small number of events reduces our certainty when comparing the safety of the approaches.

What did it find?

  • There was no difference in mortality between intracorporeal and extracorporeal anastomosis (odds ratio [OR] 0.36, 95% confidence interval [CI] 0.09 to 1.46).
  • Intracorporeal anastomosis was associated with a significant decrease in short-term morbidity, such as wound infections or transfusions required within 30 days (OR 0.68, 95% CI 0.49 to 0.93).
  • People with intracorporeal anastomosis stayed an average of 0.77 fewer days in hospital after their operation (95% CI ­-1.46 to -0.07). However, there were significant differences between the results of the individual studies (heterogeneity). There was less heterogeneity and greater certainty from more recent studies (-0.77, 95% CI ‑1.17 to -0.37).
  • Intracorporeal anastomosis was associated with a significantly lower rate of surgical site infections (OR 0.56, 95% CI 0.35 to 0.88) and earlier return of bowel function. There was no difference between procedures for anastomotic leak rate and ileus.

What does current guidance say on this issue?

NICE guidelines on management of bowel cancer recommends that, where possible, laparoscopic surgery is considered in preference to standard open surgery where a large incision is made to open up the abdomen. If the procedure is laparoscopic, guidelines do not state which technique should be used.

What are the implications?

Intracorporeal anastomosis requires training and surgical experience. One of the studies highlighted this learning curve in terms of operating time.

Studies published since 2012 had more compatible findings, which could reflect increasing familiarity with the technique and more standardised approach. However, these were still observational studies. To have greater confidence in the potential superiority of intracorporeal anastomosis, we would need randomised controlled trials to balance patient factors and that reported outcomes using validated measures.

Citation and Funding

van Oostendorp S, Elfrink A, Borstlap W, et al. Intracorporeal versus extracorporeal anastomosis in right hemicolectomy: a systematic review and meta-analysis . Surg Endosc. 2016. [Epub ahead of print].

No funding information was provided for this study.


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Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre

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