Colorectal cancer can result in malignant obstruction of the colon or rectum, through the presence of either intrinsic or extrinsic tumors. Acute or subacute bowel obstruction can lead to abdominal pain, nausea, vomiting, bowel rupture, and eventual death if left untreated.

Conventional therapies for relieving malignant colorectal obstruction include surgical resection (potentially curative) or palliative colostomy. Resection is more frequently an option in patients with less advanced cancer, and is ideally carried out as a single-stage procedure, with anastomosis to restore bowel continuity. Multistage procedures may also be undertaken, with resection and stoma formation in one procedure, followed by restoration of continuity in another procedure.1 However, a significant proportion of patients receiving a staged procedure never undergo reversal of the colostomy.2

Permanent stoma creation is the standard treatment of bowel obstruction caused by nonresectable tumors, relieving the symptoms of bowel obstruction. Although it is the standard treatment modality, stoma creation is associated with high morbidity and mortality rates, particularly when undertaken under emergency conditions.1 Furthermore, stoma creation is recognized as having a highly negative impact on patients' psychosocial well-being3 and can be a burden to caregivers as well as the patient during the final months of their life.

Endoscopic treatments to palliate rectal obstruction have also been developed in recent years but are not yet a standard treatment option. Medical management, including the use of opioids, anticholinergics, and antiemetics, is most commonly used in hospices and palliative care settings to assist in maintaining an acceptable quality of life in patients with terminal illness.

Self-expanding metallic stents (SEMS) are expandable metallic tubes that are advanced to the site of the obstruction along a guidewire in a collapsed state, under fluoroscopic and/or endoscopic guidance. Once deployed, the stents slowly expand radially to their maximum diameter under their own force, thereby achieving patency of the obstructed anatomy. Almost all stenting procedures are carried out transanally, and are generally well tolerated by patients with only conscious sedation, or no anesthesia. The value of stent placement is as a minimally invasive alternative to open surgical techniques, such as resection or stoma creation. SEMS may be used as a definitive palliative measure or can be used as a “bridge to surgery” to allow stabilization of the patient's condition before surgery is carried out as an elective procedure at a later date.

A number of stents have been designed specifically for use in the lower gastrointestinal tract and are available in a variety of lengths and diameters, so that the appropriate stent can be selected based on factors such as the length of the obstructed section of bowel and anatomic location of the obstruction.

While stenting procedures are becoming a more frequent treatment modality, it is currently unclear whether stenting represents a safe and effective alternative to surgical procedures for the treatment of malignant colorectal obstructions. The aim of this review is to assess the safety and efficacy of SEMS placement for the relief of malignant colorectal obstruction in comparison to surgical procedures through a systematic review of the literature.

Self-expanding metallic stents for relieving malignant colorectal obstruction: a systematic review.

Perforation in colorectal stenting: a meta-analysis and a search for risk factors

The placement of self-expanding metal stents (SEMS) is a safe and effective definitive procedure for the palliation of malignant colorectal obstruction. In this study, the clinical outcomes, including the technical and clinical success rates, and the risk factors associated with the long-term outcomes of palliative SEMS were evaluated. From February 2002 to April 2008, 39 patients (18 men and 21 women) with malignant colorectal obstruction underwent placement of uncovered or covered stents under fluoroscopic or endoscopic guidance. The mean age of the patients was 64.5 ± 14.6 years (range, 37–96 years). The technical success rate was 100% (39/39), and the clinical success rate was 87.2% (34/39). Five cases had failed relief of the obstruction due to the development of migration in two patients, two malfunctions, and one perforation. Four patients experienced late complications: migration managed with a palliative colostomy in two patients, tumor ingrowth managed successfully with a second stent in one patient, perforation with an intraabdominal abscess at the upper margin of the stent 4 months after stenting in one patient. The location of the obstruction and the length of the stent were significant factors associated with a good outcome. Shorter stents (<10 cm) had better outcomes than longer stents (≥10 cm; p = 0.008), and patients with a distal colorectal obstruction had better outcomes than those with a proximal colorectal obstruction (p = 0.015). Patients with bowel obstruction involving a short segment and those with a distal obstruction had better stent outcomes.

Factors associated with the long-term outcome of a self-expandable colon stent used for palliation of malignant colorectal obstruction.

Self-expanding metal stents (SEMS) are used to manage malignant colorectal obstruction. Colonic perforation is the most worrisome complication from colonic stenting. We reviewed causes and contributing factors of perforation with colonic stent placement in patients with malignant colorectal obstruction. Articles from both English and foreign language publications were identified from Medline. Data were collected on causes, timing, treatment and mortality related to perforation. A total of 2287 patients from 82 articles were included in this analysis, which showed an overall perforation rate of 4.9%. Perforation rates for palliation and bridge to surgery (BTS) were not significantly different (4.8% vs. 5.4%, p = 0.66); over 80% occurred within 30 days of stent placement (half during or within one day of the procedure). The mortality rate related to perforation was 0.8% per stented patient, but the mortality of patients experiencing perforation was 16.2%. There was no significant difference (p = 0.78) in the mortality rates between the palliation and the BTS group and concomitant chemotherapy, steroids, and radiotherapy are risk factors of perforation. The overall perforation related mortality is far less than that of patients undergoing emergency surgery for bowel obstruction.

Colonic perforation after stent placement for malignant colorectal obstruction – causes and contributing factors

Self-expandable metallic stent (SEMS) for malignant colorectal obstruction is widely used in palliative treatment and as an alternative to surgery. The aims of this study are to evaluate the effectiveness of stent placement for palliative treatment and to identify the predictive factors associated with stent occlusion. A retrospective analysis was performed in 55 patients who had undergone placement of an uncovered SEMS from February 2004 to April 2007 for palliative treatment of malignant colorectal obstruction with metastatic or locally advanced cancer that was surgically unresectable. We analyzed the technical and clinical outcomes of stent placement, complications related to the procedure, stent patency rate, and predictive factors associated with stent occlusion. The causes of colorectal obstruction before stent placement were primary colorectal cancer in 42 patients and noncolorectal extrinsic cancer in 13 patients. The initial technical success rate was 98.2%, and the clinical success rate was 94.4%. Complications occurred in 17 patients (30.9%). These included stent occlusion (n = 8), migration (n = 6), bowel perforation (n = 1), stent distortion (n = 1), and fistula formation (n = 1). The mean and median stent patency periods were 184 days [95% confidence interval (CI), 137–230 days] and 141 days (95% CI, 69–213 days), respectively. The degree of expansion 48 h after stent placement was significantly better in the nonocclusion group than in the stent occlusion group. In the multivariate Cox proportional hazard model, insufficient stent expansion (<70%) 48 h after stent placement was significantly associated with an increase in stent occlusion during the follow-up period (odds ratio, 12.55; p = 0.002). Uncovered SEMS placement is an effective palliative treatment for malignant colorectal obstruction. The degree of stent expansion 48 h after stent placement is significantly associated with the maintenance of stent patency and is a predictive factor for stent occlusion.

Effectiveness of stent placement for palliative treatment in malignant colorectal obstruction and predictive factors for stent occlusion

Abdominal wall hematoma is an uncommon cause of acute abdominal pain. We report a case of internal oblique hematoma caused by rupture of the subcostal artery in a 57-year-old woman. Ultrasonography (US) showed a hypoechoic mass in the right lateral abdominal wall. Contrast-enhanced computed tomography (CT) showed a large soft tissue mass with extravasation of contrast medium located in the right internal oblique muscle. Angiography showed contrast extravasation from the subcostal artery, and transcatheter arterial embolization was performed successfully.

Spontaneous internal oblique hematoma successfully treated by transcatheter arterial embolization

Background
In recent years, stent placement for malignant colorectal obstruction has become an accepted alternative to surgery. The purpose of this study was to evaluate the usefulness of self-expandable metallic stents (SEMS) as palliative management for patients with unresectable malignant colorectal obstruction.

Self-expandable metallic stents as palliative treatment for malignant colorectal obstruction

We report a pancreaticojejunostomy with double duct-to-mucosa anastomotic technique after pyloruspreserving pancreaticoduodenectomy for chronic pancreatitis with bifid pancreatic duct. A 49-year-old Japanese man was diagnosed preoperatively as having chronic pancreatitis with common bile duct stricture and pseudocyst of the pancreatic head. In a pancreaticoduodenectomy, the main pancreatic duct (7mm in diameter) and a secondary pancreatic duct (4mm in diameter) were identified intraoperatively at the transected surface. Pancreatography showed the main pancreatic duct as well as thesecondary pancreatic duct that drained the remaining dorsal pancreas, allowing us to diagnose bifid pancreatic duct. The pancreaticojejunostomy was performed in an end-to-side manner to create double duct-to-mucosa anastomoses and to approximate the pancreatic parenchyma and jejunal seromuscular layers. Although bifid pancreatic duct is a rare anatomical anomaly, it behooves every surgeon who performs pancreatic resections to be aware of this entity and the techniques for dealing with it.

Hiromu Hidaka

Papers

Spontaneous internal oblique hematoma successfully treated by transcatheter arterial embolization

Self-expandable metallic stents as palliative treatment for malignant colorectal obstruction

Double duct-to-mucosa pancreaticojejunostomy for bifid pancreatic duct.

Expandable metallic stent placement for malignant colonic obstruction

Duodenal perforation caused by an indwelling catheter during hepatic arterial infusion chemotherapy.