| disease | Large Intestine Obstruction |
| alias | Ileus |
Large intestine obstruction refers to the blockage from the ileocecal region to the anal region. There are many causes of obstruction, with four diseases—Michle's gastrocolic intestinal cancer, colonic volvulus, colonic diverticulitis, and extra-colonic pelvic tumors—accounting for 95% of colonic obstructions. The first two are the most common causes of complete colonic obstruction.
bubble_chart Etiology
The main causes of large intestine obstruction disease are as follows:
(1) **Cancerous obstruction**
This is the primary cause of colon obstruction. Buechtor reported that intestinal cancer obstruction accounts for 78% of colon obstructions, while literature indicates that cancerous obstructions below the splenic flexure range from 72% to 88%. Tumor locations are more common in the left colon (39%), followed by the transverse colon (27%), right colon (19%), and rectum (15%). Common sites of colon obstruction, in order, are: sigmoid colon (38%), splenic flexure (14%), descending colon (10%), transverse colon (9%), rectum (9%), cecum (6%), ascending colon (5%), and anal flexure (3%).
(2) **Colonic volvulus**
This is the second most common disease cause and can occur in the cecum, transverse colon, and sigmoid colon, with the sigmoid colon being the most frequent. According to statistics from the United States and Western Europe, 1–7% of colon obstructions are caused by colonic volvulus, with the sigmoid colon accounting for 65–80%, the right colon for 15–30%, and the transverse colon and splenic flexure being rare.
Sigmoid colon volvulus typically requires the following three conditions: ① Excessive length of the sigmoid colon; ② Contraction of the sigmoid mesentery base; ③ Increased weight within the intestinal segment (e.g., severe constipation, overeating) and external force (strong peristalsis).
(3) **Colonic schistosomiasis**
In schistosomiasis-endemic areas in China, schistosomal granulomas or associated intestinal cancers are still occasionally observed. Due to the massive deposition of schistosome eggs in the intestinal wall, repeated inflammation, damage, and repair lead to tissue hyperplasia and thickening, forming polyps that narrow the intestinal lumen and cause obstruction.
(4) **Acute pseudo-colonic obstruction (Ogilvie syndrome)**This condition was first described by Ogilvie in the UK in 1948, with many subsequent reports indicating an increasing trend in recent years. The exact disease cause remains unclear. According to literature from 1948–1980, 88% of cases were caused by extra-colonic factors such as surgery, trauma, heart failure, uremia, diabetes, ischemic colitis, metastatic tumors, hypoxia, and hypotension, while 12% had no identifiable cause. The mortality rate is 25–31% without perforation and 43–46% with perforation. Fariano suggested that this disease is related to dysfunction of the sacral parasympathetic nerves. Matsui reported that partial impairment of nerve conduction contributes to the condition, with microscopic findings showing reduced ganglion cells and degenerative changes in nerve cells within the intestinal wall. Bode reported that surgery was the primary cause in 22 cases.
(5) **Post-pelvic surgery adhesions causing colon obstruction**
The characteristics of this condition are: ① It often occurs in middle-aged women after pelvic surgery; ② Symptoms include intermittent abdominal distension and fullness, chronic abdominal pain, and constipation; ③ Barium enema reveals no specific abnormalities; ④ Colonoscopy shows angulation or narrowing of the sigmoid colon, preventing further insertion of the scope.
(6) **Obstruction caused by external tumor compression or invasion**
For example, pancreatic cancer or stomach cancer invading the transverse colon can cause obstruction. In women, pelvic tumors, particularly ovarian tumors compressing the sigmoid colon, are not uncommon causes of obstruction.
(7) **Gallstone obstruction**
This accounts for 1–3% of all intestinal obstructions, with a preoperative diagnosis rate of only 15% (13–48%). Pathways for gallstones entering the digestive tract include: ① Cholecysto-duodenal fistula (most common); ② Cholecysto-colic fistula; ③ Cholecysto-gastric fistula; ④ Common bile duct-duodenal fistula. In rare cases, gallstones may enter the duodenum directly through a dilated ampulla.
bubble_chart Pathological Changes
In cases of colonic obstruction, the ileocecal valve closes, preventing the passage of intestinal contents and resulting in a closed-loop intestinal obstruction. Due to the relatively poorer blood supply and thinner walls of the colon compared to the small intestine, even simple obstruction can easily lead to localized necrosis and perforation. The high bacterial content in the colon accelerates bacterial proliferation after obstruction, increasing the risk of systemic infection. Deitch's research indicates that 6 hours after intestinal obstruction, bacteria enter the mesenteric lymph nodes, and by 24 hours, they reach the liver, spleen, and bloodstream. In the late stage (third stage) of obstruction, intestinal wall blood flow tends to increase, allowing large quantities of bacteria and toxins to be absorbed into the circulation, exacerbating systemic toxicity and even leading to toxic shock.
Intestinal obstruction caused by volvulus can also be classified as complete or incomplete. In incomplete cases, both gas and fluid accumulate in the intestinal loop. Complete obstruction, often due to acute volvulus, is a closed-loop type. Since the passage of swallowed gas is cut off, the intestinal loop accumulates significant fluid and gas, causing extreme dilation of the affected segment, which becomes much larger than the intestine above the obstruction. This excessive distension can lead to tension-induced damage to the intestinal wall. Combined with pre-existing vascular compromise in the mesentery, the intestinal loop may hemorrhage, necrotize, leak fluid, or even perforate.
Acute pseudo-colonic obstruction often presents with marked colonic distension, and cases of necrosis and perforation are not uncommon. However, most cases can be cured without surgery.
bubble_chart Clinical Manifestations
The clinical manifestations of colonic obstruction are generally similar to those of small intestine obstruction, with the following characteristics: ① All patients experience abdominal pain. Right-sided colonic obstruction typically causes pain in the right upper abdomen, while left-sided obstruction usually causes pain in the left lower abdomen. Chronic obstruction presents with mild abdominal pain, whereas acute obstruction causes severe pain, though not as intense as that seen in volvulus or intussusception. ② Nausea and vomiting appear later or may even be absent. In the late stage (third stage), vomitus may contain yellow, fecal-like material with a foul odor. ③ Abdominal distension and fullness are more pronounced than in small intestine obstruction, with bulging on both sides of the abdomen, sometimes appearing horseshoe-shaped. ④ Cessation of defecation and flatus occurs, though most patients may still pass small amounts of gas in the early stages of obstruction. ⑤ Physical examination reveals significant abdominal distension and fullness, possibly horseshoe-shaped, with tympanic percussion notes and audible borborygmi on auscultation. Plain X-ray films show marked fluid and gas accumulation in the colon, along with fluid levels. In summary, except for colonic volvulus, the clinical manifestations of colonic obstruction are less typical and severe than those of small intestine obstruction.
Colonic obstruction can occur in any part of the colon, but it is more common in the left colon. Cancerous obstruction often presents with typical chronic colonic obstruction symptoms, such as a history of {|###|}constipation{|###|}, {|###|}diarrhea{|###|}, bloody and purulent stools, and changes in bowel habits and stool shape. Right-sided colonic obstruction causes {|###|}abdominal pain{|###|} in the right and upper-middle abdomen, while left-sided obstruction typically causes pain in the lower left abdomen. Chronic obstruction may gradually or suddenly progress to acute obstruction. Beal suggested that progressive {|###|}abdominal distension and fullness{|###|} and {|###|}constipation{|###|} in elderly individuals are typical signs of obstructive {|###|}intestinal cancer{|###|}. In healthy individuals, 10–20% have incompetent ileocecal valves, allowing some colonic contents to reflux into the {|###|}ileum{|###|}, leading to {|###|}small intestine{|###|} dilation, gas accumulation, and fluid retention, which can be misdiagnosed as low {|###|}small intestine{|###|} obstruction. If the ileocecal valve functions well, a closed-loop segment forms between the ileocecal region and the obstruction site. In this case, gas and fluid continuously enter the colon from the {|###|}ileum{|###|}, causing colonic distension, marked {|###|}abdominal distension and fullness{|###|}, complete cessation of gas and stool passage, yet vomiting may still be absent. On examination, apart from {|###|}abdominal distension and fullness{|###|}, visible bowel loops or palpable masses may be observed, and a rectal examination and X-ray should be performed. Abdominal fluoroscopy or plain films may show significant dilation of the proximal bowel loops and absence of gas in the distal loops, with fluid levels visible in the colon in an upright position. Barium enema aids in differentiation and plays a crucial role in determining the obstruction site and {|###|}disease cause{|###|}. Buechter reported diagnostic rates of 97% and 94% for abdominal plain films and barium enema, respectively.
Sigmoid volvulus often presents with a history of {|###|}constipation{|###|} or previous episodes of {|###|}abdominal pain{|###|} relieved by defecation or gas passage. Clinically, besides colicky {|###|}abdominal pain{|###|}, there is significant {|###|}abdominal distension and fullness{|###|}, while {|###|}vomiting{|###|} is generally mild. Abdominal plain films may reveal "abnormally distended double-loop bowel, horseshoe-shaped, occupying almost the entire abdominal cavity." If uncertain, a barium enema can be performed, showing a "beak sign" at the obstruction site.
Diagnosis of gallstone obstruction: ① More common in elderly, {|###|}obesity{|###|} women; ② Occurs on the basis of {|###|}cholecystitis{|###|} or gallstones; ③ Presents with intestinal obstruction symptoms; ④ X-ray plain film findings: a. Mechanical intestinal obstruction; b. Ectopic stones (stray calcified stones in the intestine); c. Gas in the biliary tract.
When diagnosis and treatment of colonic obstruction are challenging, Stewest advocates using the water-soluble contrast agent Diodone for enema. He analyzed 117 cases of {|###|}large intestine{|###|} obstruction: in the first group, abdominal plain films diagnosed 99 cases as mechanical {|###|}large intestine{|###|} obstruction, but Diodone enema confirmed only 52 cases; in the second group, 18 cases were diagnosed as pseudo-colonic obstruction, with Diodone enema confirming 15 cases, while 2 were {|###|}intestinal cancer{|###|} and 1 failed the examination. Thus, he concluded that Diodone enema aids in diagnosing and treating acute {|###|}large intestine{|###|} obstruction by confirming the presence of mechanical obstruction and avoiding unnecessary surgery for acute pseudo-colonic obstruction.
bubble_chart Treatment Measures
Intestinal cancer causing obstruction requires surgical treatment aimed at relieving the obstruction and radically removing the tumor. For right-sided intestinal cancer obstruction, most surgeons agree to perform an initial stage (first stage) subtotal resection and anastomosis. For left-sided intestinal cancer obstruction, an increasing number of authors advocate initial stage (first stage) emergency subtotal resection and anastomosis. Matsui summarized 153 cases of left-sided intestinal cancer obstruction treated with initial stage (first stage) subtotal resection and anastomosis, concluding that this procedure can address both the obstruction and the tumor in the initial stage (first stage), with advantages such as rapid postoperative recovery, low mortality (10.45%), fewer complications (25.6%), and no sequelae.
To improve surgical success rates, many authors have emphasized preoperative and intraoperative bowel preparation. Terasaka reported five cases where a long balloon tube (240 cm) was used to treat obstruction caused by intestinal cancer. The balloon tube was advanced to the obstruction site, achieving effective preoperative decompression in all five cases, with significant relief of abdominal distension and fullness. Preoperative and intraoperative decompression and irrigation can greatly enhance surgical success rates and reduce postoperative complications. He highlighted the benefits of the long tube as follows: ① Preoperative and intraoperative bowel irrigation and decompression; ② Converting emergency surgery to elective surgery; ③ Allowing preoperative antibiotic bowel preparation; ④ Enabling partial resection instead of total resection; ⑤ Safe resection and anastomosis without proximal stoma. However, the prolonged time required for the tube to reach the hepatic flexure is a drawback. Some reports suggest that intraoperative antegrade colonic irrigation for left-sided intestinal cancer obstruction can effectively relieve the obstruction, converting emergency surgery into elective surgery with good outcomes. Specifically, a Foley balloon catheter is inserted into the cecum through the base of the appendix, the balloon is inflated, and the appendix is tied tightly around the catheter. Then, 3000 ml of saline is infused through the catheter, with the last 1000 ml containing 1 g of kanamycin and 200 ml of 0.5% metronidazole to thoroughly cleanse the proximal colon. After complete drainage of the irrigation fluid, the Foley catheter is removed, and the appendix is excised. This approach not only ensures smooth initial stage (first stage) resection but also minimizes intraoperative contamination and postoperative infections. A domestic report on 45 cases of rectal cancer complicated by acute obstruction showed that only 14 patients underwent resection, with no surgical mortality. Among the 14 resections, 4 were emergency initial stage (first stage) resections, 2 were staged resections, and 8 were non-emergency surgeries. Of the 4 initial stage (first stage) resections, 3 patients survived for over 5 years, while both staged resection patients died within 5 years. Among the 8 non-emergency cases, 4 survived for 5 years. In summary, whether emergency or non-emergency, initial stage (first stage) tumor resection should be prioritized whenever possible. However, for critically ill patients, proximal colostomy remains an effective treatment for malignant obstruction. For patients with unresectable or recurrent colorectal cancer obstruction, Nd-YAG laser local tumor resection has been reported to provide short-term relief of symptoms. For colonic obstruction caused by gallstones, endoscopic stone removal is usually sufficient, avoiding the need for surgery.
Non-surgical treatment of early sigmoid volvulus; Since Brunsgaard first introduced the reduction of sigmoid volvulus by inserting a rectal tube through a sigmoidoscope in 1947, with a success rate of 86% and a mortality rate of 14.2%, a therapeutic pathway for this condition was established. Non-surgical reduction not only decreases surgical mortality but also provides time for elective surgery, making it particularly suitable for elderly and frail patients. However, due to concerns about causing intestinal perforation or delaying surgery leading to intestinal necrosis, this method was not widely adopted until the 1960s, yielding remarkable results. It is still considered that in cases without intestinal stenosis, a rectal tube should be inserted through a sigmoidoscope. Once the tube passes the twisted segment, a large amount of trapped gas and fecal fluid can be rapidly expelled, allowing the volvulus to self-reduce and promptly relieving the patient's symptoms, achieving immediate results. The rectal tube should be retained for 2–3 days to prevent early recurrence. Ten days after the reduction, an initial stage [first stage] sigmoidectomy with anastomosis should be performed. In recent years, the use of fiberoptic colonoscopy for sigmoid volvulus reduction has shown higher success rates compared to other non-surgical methods, with less blind manipulation and greater safety. Compared to sigmoidoscopic tube insertion, it offers the following advantages: ① The scope is thinner, making it easier for patients to tolerate; ② The scope is flexible, reducing the risk of injuring the intestinal wall; ③ The light source is strong, providing a clear field of view and allowing observation of the degree of mucosal edema; ④ Higher success rate of reduction—cases that fail with sigmoidoscopy can often be successfully reduced with fiberoptic colonoscopy; ⑤ It can completely aspirate gas from the proximal colon, achieving thorough decompression, and generally does not require retaining a rectal tube.
Surgical treatment: Indications for exploratory laparotomy: ①Failure of non-surgical reduction; ②Signs of intestinal necrosis or peritonitis; ③Presence of bloody fecal fluid in the intestinal lumen during colonoscopy, or necrosis or ulcer formation in the intestinal mucosa. If torsion is complicated by necrosis, intestinal resection must be performed, with Hartmann's procedure being the safer option due to fewer complications, lower mortality, and complete removal of the necrotic intestinal segment. Initial stage [first stage] resection with end-to-end anastomosis is only suitable for cases where colonic edema and intestinal dilation are not significant. If the patient's overall condition is stable and there is no severe peritonitis, resection and anastomosis on well-vascularized intestine is safe.
Ballantyne summarized the mortality rate of 2,228 cases of sigmoid volvulus: 12.4% for viable intestines and 52.8% for strangulated cases. Therefore, sigmoid volvulus should be managed as early as possible to prevent intestinal necrosis.
Gallstone obstruction: Stones <2.5cm often pass spontaneously, while stones 3cm in diameter can cause intestinal obstruction. A report of 24 cases of gallstone obstruction (stone diameter 2–4cm) showed that 23 underwent surgical treatment, including 19 with enterotomy for stone removal, 13 with exploratory laparotomy (stones in the colon), and 1 with small intestine resection. Only 1 case passed the stone spontaneously.
For acute pseudo-colonic obstruction, conservative treatment was traditionally used, such as gastrointestinal decompression, correction of typical edema and electrolyte imbalances, anti-infection, and rectal tube decompression. If necessary, cecostomy was performed. In recent years, many domestic and international authors have reported successful treatment of this condition with fiberoptic colonoscopy. Some even suggest that colonoscopy can be performed without bowel preparation, requiring only 1L of water enema 1 hour before the procedure to flush out fecal residue. During the examination, minimal air insufflation is recommended, and blind intubation should be avoided. If mucosal ischemia or bleeding is observed during the procedure, the examination should be stopped, and surgery should be considered to prevent perforation. Gosche summarized 9 groups totaling 169 cases, with 209 colonoscopic decompressions performed. The initial decompression success rate averaged 85%, recurrence rate was 25%, mortality was 2%, and 13% required surgical decompression. Indications for surgery in acute pseudo-colonic obstruction: ①Intestinal wall necrosis and signs of peritonitis; ②Cecal diameter >9cm or 12cm (due to high risk of perforation); ③Failure of conservative treatment; ④Severe respiratory distress; ⑤Diagnostic uncertainty. Cecal diameter and the timing of colonic decompression are directly related to mortality. One study showed that when the cecal diameter exceeded 14cm, the incidence of death and perforation reached 23%, with a mortality rate of 14%; whereas for diameters <14cm, necrosis, perforation, and mortality were all 7%. Performing decompression more than 7 days after onset increased mortality fivefold compared to surgery within 4 days. Emergency surgery for colonic necrosis or perforation carries a mortality rate of 10–50%. Therefore, early diagnosis and timely decompression can reduce mortality.
In summary, the treatment methods for colonic obstruction are diverse, and the choice should be based on the patient's overall and local conditions. There is no fixed surgical approach, and each clinician's experience and methods vary. Therefore, comprehensive consideration should be given to individual conditions to achieve the best outcome. Creating conditions for initial stage [first stage] resection and anastomosis is the current trend in treating intestinal cancer-related obstruction.
