الفهرس 
ANATOMY OF THE COLONOnly 14 pages are availabe for public view
 |  | from | 193 |  |  |
| | | from | 193 | | |
Abstract
C
olorectal cancer is the third most common type of cancer and second most common cause of cancer-related deaths in the United States. Colorectal cancer is predominantly a disease of aging and is a major cause of morbidity and mortality in the older population.
It is the most common type of gastrointestinal cancer. It is a multifactorial disease process, with etiology transcending genetic factors, environmental exposures (including diet), and inflammatory conditions of the digestive tract.
Due to increased emphasis on screening practices, colon cancer is now often detected during screening procedures. Other common clinical presentations include iron-deficiency anemia, rectal bleeding, abdominal pain, change in bowel habits, and intestinal obstruction or perforation. Right-sided lesions are more likely to bleed and cause diarrhea, while left-sided tumors are usually detected later and could present with bowel obstruction.
Physical findings could be very nonspecific (fatigue, weight loss) or absent early in the disease course. In more advanced cases, abdominal tenderness, macroscopic rectal bleeding, palpable abdominal mass, hepatomegaly, and ascites could be present on physical examination.
Inflammatory bowel diseases such as ulcerative colitis and Crohn’s disease also carry an increased risk of developing colorectal adenocarcinoma. The risk for developing colorectal malignancy increases with the duration of inflammatory bowel disease and the greater extent of colon involvement.
Surgical resection is the only curative treatment for resectable colorectal cancer, regardless of the patient’s age. For tumors of the abdominal colon, prohibitive anesthetic risk secondary to severe comorbidity and the presence of advanced metastatic disease are the only factors that should negatively influence the decision for surgery.
A colectomy is a surgical procedure in which all or part of the large intestine is resected. The large intestine is the part of the alimentary tract that consists of the cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum.
A colectomy that involves removing the entire colon is called a total colectomy. If most of the colon is removed, the procedure is called a subtotal colectomy. When a segment of the colon is removed, it may be called a segmental colectomy and it may be labeled a hemicolectomy to differentiate the right and left halves of the large intestine.
Laparoscopy has emerged as suitable approach for the surgical treatment of patients with benign and malignant colon conditions. Several prospective randomized trials have evaluated the efficacy of laparoscopic and open techniques, particularly for patients with colon cancer. These trials showed that laparoscopic colon surgery is more effective than open colectomy for patients with colon cancer in terms of morbidity and Length of stay(LOS) with similar mortality rates and is oncologically safe with similar disease-free and overall survival rates compared with open resection.
Most GI surgeons now accept that laparoscopic surgery for both benign and malignant diseases of the colon is within the mainstream of patient care and that it results in superior clinical outcomes(eg, length of hospital stay, surgical-site discomfort, recovery to normal activity) compared with open surgery. Laparoscopy has been associated with a lower incidence of both surgical-site infection and hernias and a greater degree of patient satisfaction compared with laparotomy.
Although concerns regarding recurrence and survival rates associated with laparoscopic colon cancer resections initially dampened enthusiasm for minimally invasive techniques, subsequent clinical studies have established that properly performed laparoscopies produce comparable colon cancer outcomes and improved clinical results.
Presently, laparoscopic colectomy for resectable colon cancer has been reported to be technically and oncologically feasible. The general consensus based on the literature over the past several years is that there is no significant difference in lymph node harvest between laparoscopic and open right hemicolectomies for cancer when strict oncologic principles of resection are followed. To date, patient survival, disease progression, and cancer recurrence at port sites have been found to be equivalent between the laparoscopic and traditional open colectomy.
Several short-term benefits similar to those described for colon cancer have been associated with laparoscopic segmental colon resection for IBD. In addition, theoretical long-term advantages include formation of fewer adhesions, decreased rates of bowel obstruction, decreased likelihood of chronic pain, and decreased incidence of infertility or wound hernias. Two recent randomized controlled trials have demonstrated some short-term benefits to laparoscopic ileocolic resection for Crohn disease. On the other hand, the current evidence on laparoscopic surgery for ulcerative colitis does not support its routine use among nonexpert surgeons outside of specialized centers. Laparoscopic colonic resection for diverticular disease appears to provide several short-term benefits, although these advantages may not translate to cases of complicated diverticulitis.
Despite the advantages afforded to patients by laparoscopy, the adoption of these techniques in the general population has been consistently limited to a minority, estimated to include a mere 20% of all colectomies performed in the United States. Much of the reticence toward implementing laparoscopic techniques is related to the challenge of complex laparoscopic surgeries such as colon resections.
Over the last 10 years, a “division of labor” has occurred within the field of minimally invasive surgical techniques, which has shaped a number of innovations that include robotic assistance, more reliable energy devices, endostaplers, and a motivation to reduce the number of access sites, even so far as limiting surgical access to a single-port approach.
In the past decade there has been growing interest in new laparoscopic treatments that could decrease morbidity and improve cosmoses further, by reducing the number of incisions and trocars. Each transabdominal entry is, in fact, associated with morbidity and risks such as port-site herniation, bleeding, damage to internal organs, and with more scarring.
Thus the emergence of the new technique Single-incision laparoscopic surgery which has been gaining momentum in general surgery and is a technique that represents a potential advance in minimally invasive surgical approaches to colorectal diseases.
Single port access surgery combines in part the advantages of natural orifice transluminal endoscopic surgery (NOTES) with the ability to perform the operation with standard laparoscopic instruments, its benefits include better cosmesis, less postoperative pain, shorter length of stay and faster recovery.
Unlike NOTES, to date, no consensus name exists for this developing technique of minimally invasive surgery. Many names seemingly centered on the type of acronym they will create have been used rather than a description of the access technique and exposure methods. One of the early names to gain popularity is single-port access (SPA) surgery, trademarked by Drexel University. Industry has begun to adopt and trademark nomenclature of its own. Covidien Inc., has been calling this new technique single-incision laparoscopic surgery (SILS), whereas Ethicon EndoSurgery, Inc. has proposed the name single-site laparoscopy (SSL). Some proposed names involve the umbilicus, such as one-port umbilical surgery (OPUS) or transumbilical endoscopic surgery (TUBS), embryonic NOTES (eNOTES), and natural orifice transumbilical surgery (NOTUS), with the embryonic notation referring to the umbilical opening in utero.
Other names suggested include single laparoscopic port procedure (SLAPP), single port laparoscopic surgery (SPLS), single-port laparoscopy (SPL) and single laparoscopic incision trans-abdominal (SLIT) surgery.
The advantages of single incision over multiple incision laparoscopic colectomy include a single small skin incision, reducing postoperative pain. Due to lack of use of specialized trocars and instruments, the cost of the procedure is not increased compared to conventional laparoscopy.
The technical difficulty in performance in SILS would be due to lack of instrument triangulation and clash of instruments and trocars outside and inside the abdomen.
In conclusion, the laparoscopic technique resulted in a reduction of both the overall morbidity rate and the length of hospital stay, and in a faster recovery of physical and social activity.