Gastrointestinal tumors have become more common in recent years in abdominal surgical diseases. Tumor-based intestinal obstruction has also increased relatively. Although the length of the small intestine is about 75% of the gastrointestinal tract, primary small intestinal tumors account for only 1% to 6% of GI tumors. Tumor-based small bowel obstruction is relatively rare. The incidence of colon and rectal tumors, especially colon and rectal cancer, is much higher than that of small intestine. The annual incidence in European and American countries reaches 30/100,000 people, while the annual incidence in developing countries such as Asia, Africa and Latin America is 2~5/100,000 people. In China, the incidence of colon and rectal cancer ranks 3rd in gastrointestinal tumors after gastric cancer and esophageal cancer. And there is a rising trend in recent years. Gastrointestinal tumors account for 8% to 29% of people who seek medical treatment for intestinal obstruction. Clinically, most of the tumor intestinal obstruction is colon obstruction.
I. Clinical manifestations and diagnosis
(A) Tumorigenic small intestine obstruction Small intestine tumor generally has no specific performance. In addition to abdominal pain and a few gastrointestinal bleeding, about 1/3 of them are diagnosed with intestinal obstruction, and the abdominal examination can mostly reveal masses. According to the nature and location of tumor, the clinical manifestations are slightly different.
1.Benign tumor of small intestine Benign lesions in small intestine tumor account for 20%. Those that can lead to intestinal obstruction include smooth muscle tumor, adenoma and adenomatous polyp, lipoma, fibroma, nerve sheath tumor and so on. Due to the slow development of benign tumor of small intestine, the obstruction is often manifested as abdominal pain and chronic slow progressive incomplete intestinal obstruction with a long course.
Malignant tumor of small intestine accounts for 80% of small intestine tumor. The more common pathological types are malignant lymphoma, malignant adenoma, smooth muscle sarcoma, carcinoid tumor, malignant nerve sheath tumor and so on. Malignant tumors of the small intestine are more malignant and most of them present as rapidly progressing abdominal masses and incomplete intestinal obstruction. They are often accompanied by different degrees of pain. Regardless of benign or malignant small intestinal tumors, some cases can have different degrees of gastrointestinal bleeding. Depending on the location of the lesion, it may present as upper or lower gastrointestinal bleeding. Once it is accompanied by intussusception or intestinal torsion, acute and complete intestinal obstruction may occur.
3, chronic incomplete small intestinal obstruction with abdominal masses Small intestinal tumors should be highly suspected. B-type ultrasound and CT examination can confirm the location, size and enlarged mesenteric lymph nodes of the mass and other positive signs, so there is no difficulty in diagnosis. However, it should be emphasized that once a mass is found in the abdomen with chronic incomplete or acute complete intestinal obstruction, it should be promptly investigated surgically to avoid delaying treatment.
(2) Tumor colon obstruction Due to the recent progress of diagnostic technology, double contrast contrast imaging and fiber colonoscopy are widely used, so there is no great difficulty for the early diagnosis of colon cancer. However, due to the lack of obvious symptoms in the early stage, or insufficient awareness and vigilance, 8% to 29% of patients still seek medical treatment for intestinal obstruction in the middle and late stages, which often requires emergency surgery, adding many unfavorable factors to the treatment and prognosis. Therefore, if early symptoms such as hidden abdominal pain, change in bowel habit, mucus and blood stool or unexplained anemia, weakness or even lower abdominal mass occur, corresponding examination should be conducted in time and early diagnosis and treatment is extremely important. The most common sites of colon and rectal cancer are rectum, sigmoid colon, cecum, hepatic flexure of colon, splenic flexure, descending colon, ascending colon and transverse colon in order. However, the most frequent sites of obstruction are splenic flexure (about 50%), followed by descending colon, sigmoid colon (25%), right hemicolectomy (8%-30%), and rectum (6%). This is because the caliber of the left hemicolectomy is smaller than that of the right hemicolectomy, the intestinal contents are mostly semi-solid, and the tumor is mostly infiltrative and narrowing growth, so obstruction can easily occur.
Complicated obstruction of colon cancer may manifest as acute sudden or chronic progressive, complete or incomplete low bowel obstruction. Chronic incomplete intestinal obstruction can sometimes be transformed into acute complete intestinal obstruction. Due to the role of ileocecal valve, when complete obstruction occurs in colon cancer, it can present the pathological changes of closed-collar intestinal obstruction; the intestinal tube is severely dilated and the blood transport of intestinal wall is impaired, which easily causes necrosis and perforation. The possibility of tumor is high for unexplained low-level intestinal obstruction in middle-aged and old people. Abdominal pain, abdominal distension and abdominal mass are the main manifestations of tumorigenic low intestinal obstruction. However, in the case of severe abdominal distension of colonic obstruction, it is usually difficult to find the mass. Although stopping defecation and exhaustion is one of the main symptoms of complete intestinal obstruction, in some cases, after the occurrence of abdominal pain and obstruction, a small amount of residual gas and stool is still expelled from the distal colon, which should be alerted to avoid delaying diagnosis. For sigmoid colon and descending colon obstruction, in addition to pain in the left lower abdomen, X-ray abdominal radiographs can show inflated and dilated colon above the obstruction, so the diagnosis is not difficult. Acute obstruction of right hemicolectomy, especially ileocecal and ascending colon cancer, is easily misdiagnosed as acute appendicitis and appendiceal abscess. It has been reported that 10%-25% of right hemicolectomy cancers are mistaken for acute appendicitis. Barium enema angiography and fiberoptic colonoscopy with pathological biopsy are the main means to determine the location and nature of colon lesions. If necessary, B-mode ultrasound and CT examination can help to understand the status of tumor masses. For chronic incomplete colonic obstruction, the diagnosis can be clearly made before surgery by the above mentioned examinations. However, for acute complete obstruction, it is often too late or inappropriate to conduct complex examination in the case of severe disease, and timely surgical investigation is appropriate.
Treatment
So far, the effective treatment of gastrointestinal tumor is still mainly surgical resection. If the tumor is combined with intestinal obstruction, the tumor should be removed surgically to relieve the obstruction.
(I) Pre-operative preparation The principles of general pre-operative preparation for intestinal obstruction should be followed.
(1) Timely correction of water, electrolyte and acid-base balance;
(2) Effective gastrointestinal decompression;
(3) Prevention and control of local and systemic infections, intestinal bacterial translocation is likely to occur in intestinal obstruction, it is appropriate to use anti-Gram-negative bacteria and anaerobic bacteria drugs, generally choose broad-spectrum antibiotics plus metronidazole as the main;
(4) Tumor intestinal obstruction is mostly in middle-aged and elderly patients, detailed medical history of heart, lung, liver, kidney and other functions should be inquired and corresponding examinations should be performed to understand the functional status of each organ to prevent intraoperative and postoperative dysfunction of important organs;
(5) For incomplete intestinal obstruction, appropriate intestinal preparation, such as oral intestinal antibacterial drugs and laxatives, is feasible before surgery.
(2) The choice of surgical methods for tumorigenic small bowel obstruction is relatively consistent. The tumor intestinal segment and the corresponding mesentery and regional lymph nodes should be resected and anastomosed in one stage, and the intestinal cutting edge should be at least 5 cm away from the tumor. If the tumor breaks through the plasma membrane and adheres to the nearby intestinal collaterals or omentum, the whole piece should be removed. According to the nature and extent of the tumor, the lymph nodes in the vicinity and mesenteric root should be cleared as much as possible.
(3) Surgical method selection for tumor-based colonic obstruction Radical surgery should be performed as far as possible under the premise of releasing the obstruction. For chronic incomplete obstruction, radical one-stage resection anastomosis is effective after more adequate preoperative and proper intestinal preparation. However, in acute complete obstruction, infection and anastomotic fistula are likely to occur because of the thin colon wall, poor blood supply and colon contents are mostly solid or semi-solid, containing many bacteria and complex strains of bacteria. In addition, tumor colon obstruction is predominantly in the elderly, with many co-morbidities in various organs, low compensatory function, and reduced immune function, which makes surgery poorly tolerated and prone to surgical complications and high morbidity and mortality rates. Therefore, the risk of performing emergency one-stage colectomy anastomosis without intestinal preparation is high. Before the 1950s, emergency one-stage surgery was not advocated, but after the 1960s, with the emergence of powerful antibacterial drugs, intraoperative intestinal decompression and irrigation techniques, and advances in surgical techniques, there were reports of satisfactory results of emergency one-stage colectomy anastomosis. By the early 1990s, the rate of one-stage resection and anastomosis for right hemicolectomy combined with obstruction had reached more than 80%. However, the treatment of acute obstruction of the left hemicolectomy is still controversial.
The focus of the debate on emergency surgery for left hemicolon obstruction is whether it is better to choose one-stage surgery or staged surgery. The traditional method is to operate in stages. The proximal end of the obstruction is first decompressed by intestinal stoma to release the obstruction, and the lesion is removed in the second stage. Because the left hemicolectomy cavity contains a large amount of fecal matter containing bacteria, it is easy to contaminate the abdominal cavity, anastomosis and incision; the proximal colon of obstruction is dilated and edematous, and the caliber of the distal intestinal cavity is very different, so anastomotic fistula can easily occur after anastomosis. The risk of first-stage resection anastomosis is high, and once an anastomotic fistula occurs or fecal peritonitis is formed, the morbidity and mortality rate can be 25% to 50%. However, the main problem with staged surgery is the long hospital stay, increased hospital costs, and the need to endure the pain of reoperation. However, in recent years, with advances in medical conditions and technology, there has been a gradual increase in the number of advocates of one-stage resection and anastomosis. More and more scholars now believe that, in general, the complications and mortality of one-stage surgery are similar to those of staged surgery, but it can shorten the hospital stay, improve the 5-year survival rate, and avoid the pain of reoperation. Of course, not all cases are suitable for one-stage surgery, and appropriate indications should be selected to achieve the expected results.
(1) The patient is in fair general condition, has no serious coexisting disease, and can tolerate radical surgery;
(2) The duration of obstruction is short, the edema of the intestinal wall is mild, and the blood supply is good;
(3) The difference in the caliber of the proximal and distal intestinal canal is not great. If the obstruction time is long, the condition is serious, the tumor infiltrates and adheres to the surrounding, it is difficult to resect or the intestinal wall is necrotic and perforated, and the abdominal cavity is seriously polluted, it is still appropriate to operate in stages.
2.Selecting the operation mode Obstructive colon obstruction should be selected according to the patient’s general condition and local pathology.
(1) If the general condition of the patient is good and meets the requirement of one-stage resection and anastomosis, one-stage radical resection and end-to-end proximal and distal intestinal anastomosis are feasible. However, attention must be paid to intraoperative perfect proximal colonic decompression and clean irrigation. The anastomosis should have good blood supply and no tension, and the anus should be dilated daily after surgery to prevent excessive tension in the intestinal cavity to ensure the safety of the anastomosis.
(2) If there is a large disparity between the proximal and distal intestinal lumen, significant inflammatory edema in the intestinal wall, poor blood supply or high tension in the anastomosis after the first-stage radical resection anastomosis, an adjuvant transverse colostomy can be added to prevent anastomotic fistula.
(3) After the first-stage radical resection, it is found that the intestinal end is severely inflamed and edematous, the blood supply is poor or the distal and proximal ends are too far apart, and the first-stage anastomosis is difficult. When the patient recovers and the situation permits, the second-stage surgery will be performed to restore the intestinal continuity.
(4) If the patient’s general condition is poor or the scope of tumor infiltration and adhesion is large, and the first stage resection is difficult and dangerous, the proximal intestinal collaterals of obstruction can be stomaed. After the patient’s general condition is restored, radical phase II surgery will be performed after intestinal preparation.
(5) If the tumor invades important organs or has extensive metastasis or spread, and there is no possibility of radical resection, palliative proximal intestinal stoma or shortcut surgery is feasible.
Intraoperative intestinal decompression and lavage In emergency surgery for complete intestinal obstruction, there are a lot of bacterial contents stored in the severely distended intestinal canal, which hinders the exposure and operation of the surgical field and easily contaminates the abdominal cavity, affecting the healing of anastomosis and postoperative recovery. Especially in the case of left hemicolectomy anastomosis, effective intraoperative decompression and clean irrigation must be performed to facilitate the restoration of blood supply to the intestinal wall and reduce the chance of contamination. The most common method of intraoperative intestinal decompression and irrigation can be used to cut open the proximal end of the diseased intestinal segment, put in a larger caliber hose, and aspirate the intestinal contents directly with a suction device under airtight conditions. Irrigation with warm 0.9% sodium chloride solution, and then with 0.5% metronidazole 500mL irrigation until the effluent is basically clear.
4, routine flushing of the peritoneal cavity before closing the abdomen after surgery flushing solution with 0.9% sodium chloride solution plus metronidazole. In recent years, it has been reported that rinsing the abdominal cavity with sterilized distilled water soaking is beneficial to destroy the activity of exfoliated tumor cells. Then put in appropriate amount of antibacterial drugs such as metronidazole and gentamicin and place abdominal drainage.
(IV) Postoperative treatment Treat as general postoperative intestinal obstruction, and strengthen antibacterial therapy and nutritional support. Once an anastomotic fistula occurs, it is necessary to clear the drainage, prevent diffuse peritonitis, and strengthen total parenteral nutrition. After healing and basic recovery of the trauma, chemotherapy should be administered as early as possible.