Minimal invasive surgery is defined as a surgical method using a smaller skin incision (or no skin incision) compared with classic open surgical procedures. In gastrointestinal surgery the evolution has typically gone from open surgery to laparoscopic surgery, from laparoscopic surgery to endoscopy (e.g. gastroscopy, colonoscopy, etc.), and from endoscopy to non-invasive methods (see Figure 1). The choice of surgical procedure is, however, dependent on many factors (see Box 1) and that is why the evolution can sometimes go the opposite way, depending particularly on method-specific complications and economic considerations.

Minimal invasive surgery (MIS) is a natural way of decreasing the surgical stress response, just like using intraoperative regional anaesthesia (e.g. epidural blockade) and pharmacological blockade (e.g. preoperative injection of steroids such as dexamethasone). MIS, i.e. typically laparoscopic surgery, especially contributes to reduction of the inflammatory stress response (reduced secretion of interleukin-6, leucocytosis, acute phase proteins etc.), preservation of immune function, better lung function and reduced duration of bowel paralysis after operation. All together, laparoscopic surgery will produce a reduction in the occurrence of postoperative fatigue, therefore shortening the convalescence period. This can, for instance, be seenafter open cholecystectomy, where a significant number of patiens are severely fatigued 30 days after operation,¹ whereas after laparoscopic cholecystectomy the level of fatigue is at a preoperative level already at day three after operation.²

Laparoscopic surgery has been known for decades, but in abdominal surgery has only been performed routinely within the last 15 years. Laparoscopic surgery is therefore now an established method for both diagnostic and therapeutic procedures and is used routinely in almost all surgical departments. The endoscopic procedures (through natural openings) can be used typically for diagnosing various diseases in the oesophagus, stomach, duodenum, distal ileum, colon and rectum. It is possible to take biopsies and to do some surgical procedures as well. This area is in very fast evolution and in a few years we will see a lot of therapeutic possibilities where the endoscopists will take over many of the procedures now performed by surgeons.

Laparoscopy
Compared with the corresponding open operations the laparoscopic operations have a number of advantages. The trauma of surgery is reduced, thus impairing a number of the ‘normal’ complications to open surgery such as wound infection, pneumonia, cardiac complications, etc. The reduced surgical stress response will also decrease the duration of the convalescence period after operation, which is the time for resuming normal leisure activities and work. Finally, laparoscopic surgery will reduce pain after operation compared with the same open procedure. Also, there seems to be a tendency towards lesser peritoneal adhesions after laparoscopic surgery, probably reducing ileus complications in the long term compared with open surgery.