First, the small surgical wound created in laparoscopic colorectal surgery results in less tissue damage than that observed in open surgery. The reduced tissue damage results in lower cytokine and immune responses, which leads to a faster recovery after surgery. In laparoscopic surgery CO₂ is used to insufflate the abdominal cavity. By using CO₂ insufflation, surgeons can prevent the direct exposure of intraperitoneal organs to the air. Exposure of the intraperitoneal organs to air may suppress immune response which is detrimental to the patient’s postoperative recovery, and performing pneumoperitoneum using C0₂ may prevent such changes (Hanly et al. 2003). In most previous studies, the amount of blood loss was significantly less in patients undergoing laparoscopic colectomy than in those treated with open surgery. This is due to the ability to precisely observe the intraperitoneal organs and tissue using the laparoscope and meticulous operative maneuvers. Reducing the amount of blood loss is beneficial for improving the patient’s recovery from the surgical intervention. Open colectomy involves the manual manipulation of the intestines by the surgeons which induces a significant inflammatory response, possibly leading to paralytic ileus and postoperative adhesions of the intestine (Schwarz et al. 2004). Because the amount of bowel manipulation in laparoscopic surgery is much less than that observed in open surgery, the invasiveness of laparoscopic surgery is considered to be minimized.

Surgical intervention is generally considered to result in the suppression of cell-mediated immunity, an increased level of cytokines, and an enhanced inflammatory response. It has been reported that in patients undergoing laparoscopic colectomy, the postoperative rise in levels of IL-6, IL-8, IL-10, and CRP is less than observed in open colectomy (Wichmann et al. 2005). This finding is considered to be due to the reduced invasiveness of laparoscopic surgery comparing to open surgery.

In our previous study comparing laparoscopic vs. open surgery with respect to the cytokine response and inflammatory changes, the rise in the IL-6 levels was significantly lower in the lap colectomy than in the open colectomy group. Similar data have been reported in a number of previous papers. As for the hormonal response, the rise in the ADH and ACTH levels did not differ between the laparoscopic group and the open surgery group (Fig. 8.3) (Ozawa et al. 2000).

The evaluation of surgical risks in patients undergoing laparoscopic colectomy is usually performed in a similar manner to that of open surgery. There is a tendency toward longer operation time in cases of laparoscopic colorectal surgery. Performing pneumoperitoneum using CO₂ may cause hypercapnia and decrease the cardiac output. Therefore, in patients with severe cardiovascular and pulmonary dysfunction, the indication for laparoscopic colorectal surgery should be carefully evaluated.

There are several assessment tools commonly used to evaluate surgical risks. Some of these tools require specific assessment and interventions using an integrative and team-based approach. Various factors including symptoms, comorbidities, and laboratory data have been identified to be important surgical risk factors. The patient’s age itself may not be a risk factor; however, comorbidities and frailty associated with old age are considered to be risk factors in surgical patients. The followings are representative operative risk assessment tools.

Stenosis or obstruction due to colorectal cancer should be dealt with somewhat differently than using open surgery. This is because the ability to expose the operating field during laparoscopic procedures is difficult in the presence of distension of the large or small bowel or both. Therefore, in cases of laparoscopic colorectal surgery, stenosis or obstruction should be managed to resolve distension in the bowel proximal to the tumor. When there is stenosis without symptoms of bowel obstruction, the patient is advised to stop taking solid food and to consume only liquids. This allows the feces accumulated in the bowel proximal to the tumor to be eventually passed through the stenotic segment. It usually takes approximately a week for the accumulated feces to pass through the stenosis.

On the other hand, when there is obstruction due to a tumor, decompression of the distended bowel proximal to the tumor should be attempted before resection. The most effective way to decompress the bowel is to either construct a stoma or place a self-expandable colonic stent via a colonoscopic procedure. Stenting is effective for achieving decompression and is useful as a bridge to surgical resection. The procedure requires a high level of technique and is usually performed by a well-trained colonoscopist to avoid complications during stent insertion (Fig. 8.4) (Sarkar et al. 2013). Therefore, collaboration between surgeons and endoscopists is essential. There are certain limitations associated with this procedure. When the tumor is situated around the acute bend of the colon, inserting the stent is technically difficult. In addition, if the obstruction is severe and it is not possible to pass a guidewire through the tumor, it is technically impossible to place a stent. As for the site of the tumor, the patients with mid to lower rectal tumors are usually not indicated for stenting. This is because the distal portion of the stent may project into the lower rectum causing difficulty performing rectal resection. Although not always unsuccessful, performing stent insertion of the transverse or the right colon can be difficult due to the instability in colonoscopic manipulation. Although there are technical problems and the long-term outcomes of colon cancer patients who undergo stenting as a bridge to surgery are still controversial (Sabbagh et al. 2013), colonic stenting is an effective modality for decompressing the obstructed colon before laparoscopic surgery.