With the introduction of laparoscopic colectomy nearly 20 years ago, a relatively slow adoption of laparoscopic colorectal surgery into surgical practice has taken place. It is estimated that 10% to 25% of all colorectal resections are performed utilizing laparoscopy. The persistent steep learning curve, the lack of high-volume colorectal surgery by general surgeons (who perform the bulk of colonic resection in the United States), and the modest advantages reported are but a few of the reasons that the percentage of laparoscopic colorectal procedures has not dramatically risen. With the publication of several large, prospective randomized trials for colon cancer, along with the interest in single-port surgery and natural orifice surgery, there appears to be a renewed interest in minimally invasive procedures for the colon and rectum. This chapter will provide an overview of these issues and offer a current assessment of the common diseases to which minimally invasive techniques have been applied.
Numerous previous studies have evaluated the learning curve involved in laparoscopic colectomy. It is estimated by conventional laparoscopic techniques that the learning curve for laparoscopic colectomy is at least 20 cases but more likely 50 cases. The need to work in multiple quadrants of the abdomen, the need for a skilled laparoscopic assistant, and the lack of yearly volume has kept the learning curve relatively steep. The surgeon may also need to work in reverse angles to the camera. All of these combined add to the complexity of the procedure and result in the need to perform a number of cases before the surgeon and surgical team become proficient. More recent publications have suggested the learning curve is more than 20 cases. In a prospective randomized study of colorectal cancer in the United Kingdom, the CLASICC trial, surgeons had to perform at least 20 laparoscopic resections before they were allowed to enter the study. The study began in July 1996 and was completed in July 2002. Despite the surgeons’ prior experience, the rate of conversion dropped from 38% to 16% over the course of the study, suggesting that a minimum of 20 cases may not be enough to overcome the learning curve. In the COLOR trial from Europe, another prospective randomized study for colon cancer that required a prerequisite experience in laparoscopic colon resection before surgeons could enter patients in the study, surgeon and hospital volume were directly related to a number of operative and postoperative outcomes. The median operative time for high-volume hospitals (>10 cases/year) was 188 minutes, compared to 241 minutes for low-volume hospitals (<5 cases/year); likewise, conversion rates were 9% versus 24% for the two groups. High-volume groups also had more lymph nodes in the resected specimens, fewer complications, and shortened hospital stays. These two relatively recent multicenter studies suggest that the learning curve is clearly greater than 20 cases and that surgeons need to perform a minimum yearly number of procedures to maintain their skills.
There may not be another area in recent surgical history that has been more heavily scrutinized than laparoscopic colorectal surgery. The plethora of accumulated data allows a careful assessment of all outcome measures for nearly every colorectal disease and procedure. In comparison to conventional colorectal surgery, the benefits of laparoscopy for colorectal procedures compared to open techniques include a reduction in postoperative ileus, postoperative pain, and a concomitant reduction in the need for analgesics; an earlier tolerance of diet; a shortened hospital stay; a quicker resumption of normal activities; improved cosmesis; and possibly preservation of immune function. This is offset by a prolongation in operative time, the cost of laparoscopic equipment, and the learning curve for these technically challenging procedures. When reporting the outcomes of laparoscopic colectomy, a natural selection bias applies when comparing conventional and laparoscopic cases. The most complex cases are generally not suitable for a laparoscopic approach and therefore are performed via an open approach. Also, in many series the results of the successfully completed laparoscopic cases are compared to conventional cases, and the cases converted from a laparoscopic to a conventional procedure may be analyzed separately. Few studies, with the exception of the larger prospective randomized studies, leave the converted cases in the laparoscopic group as part of the “intention to treat” laparoscopic group. This clearly introduces selection bias.
Although the results of prospective randomized trials are available for almost every disease process requiring colorectal resection, the majority of studies of laparoscopic colectomy are retrospective case-control series or noncomparative reports. The conclusions regarding patient outcomes must therefore come from the repetitiveness of the results rather than the superiority of the study design. For any one study, the evidence may be weak; but collectively, because of the reproducibility of results by a large number of institutions, even with different operative techniques and postoperative management parameters, the preponderance of evidence favors a minimally invasive approach with respect to postoperative outcomes.
Nearly all the comparative studies provide information regarding operative times. The definition of the operative time may vary with each series, and there may be different groups of surgeons performing the laparoscopic and conventional procedures. With the exception of a few reports, nearly all studies demonstrated a prolonged operative time associated with laparoscopic procedures. In prospective randomized trials, the procedure was roughly 40 to 60 minutes longer in the laparoscopic groups. As the surgeon and team gain experience with laparoscopic colectomy, the operating times do reliably fall, but rarely do they return to the comparable time for a conventional approach.
Return of Bowel Activity and Resumption of Diet
Reduction in postoperative ileus is one of the proposed major advantages of minimally invasive surgery. Nearly all of the retrospective and prospective studies comparing open and laparoscopic colectomy have shown a statistically significant reduction in the time to passage of flatus and stool. Most series demonstrate a 1- to 2-day advantage for the laparoscopic group. Whether the reduction of ileus relates to less bowel manipulation or less intestinal exposure to air during minimally invasive surgery remains unknown. With the reduction in postoperative ileus, the tolerance by the patient of both liquids and solid foods is quicker following laparoscopic resection. The time to resumption of diet varies from 2 days to 7 days, but in the majority of comparative studies, this is still 1 to 2 days sooner than in patients undergoing conventional surgery. Again, the physician and patient were not blinded in nearly all studies, which may have altered patient expectations. However, the overwhelming reproducible data reported in both retrospective and prospective studies of laparoscopic procedures does likely favor a reduction of postoperative ileus and tolerance of liquid and solid diets.
To measure postoperative pain, a variety of assessments have been performed to demonstrate a significant reduction in pain following minimally invasive surgery; some studies utilize an analog pain scale, and others measure narcotic requirements. Physician bias and psychologic conditioning of patients may interfere with the evaluation of postoperative pain. There are also cultural variations in the response to pain. Three of the early prospective randomized trials have evaluated pain postoperatively, and all three have found a reduction in narcotic requirements in patients undergoing laparoscopic colectomy. In the COST study, the need both for intravenous and oral analgesics was less in patients undergoing successfully completed laparoscopic resections. Numerous other nonrandomized studies have shown a reduction in postoperative pain and narcotic usage.
Length of Stay
The quicker resolution of ileus, earlier resumption of diet, and reduced postoperative pain has resulted in a shortened length of stay for patients after laparoscopic resection when compared to traditional procedures. Recovery after conventional surgery has also been shortened, but in the absence of minimally invasive techniques, it would seem unlikely that the length of stay could be further reduced. In nearly all comparative studies, the length of hospitalization was 1 to 6 days less for the laparoscopic group. Although psychological conditioning of the patient cannot be helped and likely has a desirable effect, the benefits of minimally invasive procedures on the overall length of stay cannot be discounted. The benefit, however, is more likely a 1 to 2 day advantage only. The more recent introduction of clinical pathways, both in conventional and laparoscopic surgery, has also narrowed the gap but appears to be more reliable in patients undergoing a minimally invasive approach.
One of the disadvantages of laparoscopy is the higher cost related to longer operative times and increased expenditures in disposable equipment. Whether the total cost of the hospitalization (operative and hospital costs) is higher following laparoscopic colectomy is debatable. A case-control study from the Mayo Clinic looked at total costs following laparoscopic and open ileocolic resection for Crohn’s disease (CD). In this study, 66 patients underwent laparoscopic or conventional ileocolic resection and were well matched. Patients in the laparoscopic group had less postoperative pain, tolerated a regular diet 1 to 2 days sooner, and had a shorter length of stay (4 vs. 7 days). In the cost analysis, despite higher operative costs, the overall mean cost was $3273 less in the laparoscopic group. The procedures were performed by different groups of surgeons at the institution, and although the surgeons may have introduced biases, this study was undertaken during the current era of cost containment, in which all physicians are encouraged to reduce hospital stays. The results are similar for elective sigmoid diverticular resection with a mean cost savings of $700 to $800. Clearly, if operative times and equipment expenditure are minimized, the overall cost of a laparoscopic resection should not exceed a conventional approach.