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Published online before print April 19, 2002, 10.1148/radiol.2233010866
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(Radiology 2002;223:715-722.)
© RSNA, 2002

Vascular and Interventional Radiology

Metallic Stents in the Treatment of Benign Diseases of the Colon: Preliminary Experience in 10 Cases1

Laura Paúl, MD, Isabel Pinto, MD, Helena Gómez, MD, Rosa Fernández-Lobato, MD and Emilio Moyano, MD

1 From the Departments of Radiology (L.P., I.P., H.G.), Surgery (R.F.L.), and Gastroenterology (E.M.), University Getafe Hospital, Carretera de Toledo Km 12,5, 28905 Getafe, Madrid, Spain. Received April 30, 2001; revision requested June 5; revision received September 10; accepted October 16. Address correspondence to L.P. (e-mail: laura.paul@teleline.es).


   ABSTRACT
TOP
 ABSTRACT
INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
 REFERENCES
 
PURPOSE: To assess the effectiveness of and complications associated with metallic stent placement for treatment of benign diseases of the colon.

MATERIALS AND METHODS: With radiologic guidance, the authors placed metallic stents in 10 patients with benign diseases of the colon: Nine stents were placed in the rectosigmoid colon, and one was placed in the descending colon. The stents were placed in two cases of diverticulitis complicated by pelvic abscess, four cases of colonic fistula following surgery, and four cases of postsurgical anastomotic stricture. Coated stents were placed in the cases involving fistulas and diverticulitis.

RESULTS: In the two cases of diverticulitis complicated by pelvic abscess, the coated stents helped to resolve the abscesses, but both patients subsequently developed complications: fistula and perforation. Of the four cases of colonic fistula, two were resolved with stent placement. In the four cases of postsurgical stenosis, the stents temporarily relieved the symptoms of obstruction, but additional treatments were required before the patients became entirely asymptomatic.

CONCLUSION: Metallic stents may represent an effective temporary treatment for certain benign colonic conditions in the absence of other therapeutic alternatives.

© RSNA, 2002

Index terms: Colon, CT, 75.12111 • Colon, diseases, 75.273, 75.458, 75.791, 75.792 • Colon, radiography, 75.1283 • Colon, stenosis or obstruction, 75.458, 75.791, 75.792 • Colon, surgery, 75.245, 75.256, 75.458 • Stents and prostheses, 75.1289


   INTRODUCTION
TOP
 ABSTRACT
 INTRODUCTION
MATERIALS AND METHODS
 RESULTS
DISCUSSION
 REFERENCES
 
The deployment of stents in the esophagus with endoscopic or radiologic guidance is a well established procedure and has proved effective as a palliative therapy for malignant esophageal dysphagia (1–3). Within the past 10 years, this technique has also been used for the treatment of malignant strictures of the stomach (4) and colon (5–14).

According to the limited experiences reported in the literature (15–17), the use of stents for benign gastrointestinal disorders (ie, stenoses and fistulas) is, a priori, less effective and more problematic than that for malignant disease. Stent placement generally is not indicated for benign lesions because of the potential for short-term stent occlusion and the risk of perforation of the digestive tract as a result of mural abrasion. Even so, with certain pathologic conditions, few therapeutic options are available, making it appropriate to consider less orthodox treatments, such as stent placement. Moreover, in contrast to the situation in other regions of the digestive tract, in the colon, stent removal and expulsion are possibilities, as is surgical resection of the segment in which the stent has been placed. This extends the range of potential indications for stent deployment in both malignant and benign lesions. The literature contains reports of some experiences with stents in the treatment of benign rectosigmoid colon lesions—for example, ischemic stenoses (18), postsurgical strictures (19,20), stenoses subsequent to diverticulitis (21,22), and fistulas (23,24).

The purpose of this study was to evaluate stent placement as a treatment for benign conditions of the colon, primarily the sigmoid colon. In this article, we report our experiences with stents in the treatment of these benign conditions and discuss the indications, therapeutic results obtained, and complications encountered to add to the limited experiences that have been reported on this subject.


   MATERIALS AND METHODS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS
DISCUSSION
 REFERENCES
 
For the past 6 years we have used metallic stents therapeutically in 10 patients (four women, six men; mean age, 62.7 years) with a variety of benign colonic disorders. Our study had institutional review board approval, and informed consent was obtained from all patients.

Clinical Indications
There were two cases of diverticulitis (patients 1 and 2) complicated by pelvic abscess that failed to resolve with antibiotics and percutaneous drainage; serious risks made these patients unacceptable for surgery. Both of these patients had fever and pain, although they did not have bowel obstruction.

There were four cases (patients 3–6) of colonic fistula following surgery for various causes—namely, sigmoid cancer, cancer of the descending colon, bladder cancer, and diverticulitis—which resulted in fever, pain, and altered transit of intestinal material. In patients 3 and 4, barium enema examination revealed substantial colonic stricture at the site of the surgical anastomosis associated with the fistula. In patients 5 and 6, only fistulas were present, without stricture.

There were four cases (patients 7–10) of anastomotic stricture following surgery for colonic cancer (three patients) and diverticulitis (one patient), in which the primary symptom was bowel obstruction. One of these patients (patient 9) had undergone radiation therapy postsurgically.

Imaging and Stent Placement
In all cases, we confirmed the clinical diagnosis by performing corresponding diagnostic ultrasonography (US), computed tomography (CT), cystography, and/or barium enema examination. In addition, either the same day or the day before the stent placement procedure, we performed a single-contrast barium enema study prior to stent placement in all cases to determine the presence and precise location of the lesion, the presence and characteristics of the fistula (if any), and the length and degree of stenosis (where present).

The stents used ranged from 70 to 100 mm in length and from 20 to 22 mm in diameter. Four noncoated stents (Oesophageal Wallstent; Schneider Europe, Bülach, Switzerland) were placed in patients 7–10, and six silicone-coated stents (Wallstent; Schneider Europe) were placed in the two cases of diverticulitis (patients 1 and 2) and in the four cases involving fistulas (patients 3–6). In addition, two coil-type endoprostheses (Esophagocoil; Mettronic Instent, Eidenprairie, Minn) were placed in patients 7 and 8.

With the patient supine, a catheter was inserted over a hydrophilic guide wire through the anus to the lesion targeted with fluoroscopic guidance. A 110-cm 7-F Berenstein catheter (USCI; Bard Ireland, Galway, Ireland) or a 65–120-cm catheter (Savonia or Vertebral; Cordis Europa, Roden, the Netherlands) with a 0.35-inch guide wire (Terumo Guide Wire, Terumo, Frankfurt, Germany or Roadrunner, Cook Group, Bjaeverskov, Denmark) was used. The guide wire was maneuvered past the stricture or fistulous track, and the catheter was advanced. This guide wire was then replaced with another guide wire (Amplatz Super Stiff Guide Wire; Meditech Boston Scientific, Watertown, Mass) for stent delivery and insertion. The stent was then positioned precisely across the lesion and released. No balloon dilation of the stents was carried out after release.

Stent placement was performed by experienced interventional radiologists (L.P., I.P., H.G.) in all cases. For patient 1, the assistance of an endoscopist (E.M.) also was required. In this case, the initial attempt to traverse the stricture with radiologic guidance failed, but a second attempt carried out with endoscopic guidance was successful. Once the lesion was passed by the guide wire, the procedure was continued by using the technique just described.

Broad-spectrum antibiotics were administered to only the patients with diverticulitis, who were already receiving appropriate antibiotic medications. Otherwise, the procedure did not include administration of antibiotics. All stents were placed successfully in the region of the disease process.

Follow-up Protocol
No special care was required after the procedure. In all patients, a conventional radiograph was obtained 24 hours after stent placement to confirm the proper placement and expansion of the stents and to rule out perforation. Subsequently, different examinations were carried out, depending on the indications for stent placement and the clinical progress of the patient: Barium enema examination was performed to evaluate the closure of the fistulas; CT was performed to verify the resolution of abscesses; and endoscopy, US, and/or CT was performed if complications such as rectal bleeding, peritonism, or pain occurred.

All imaging and/or endoscopic studies needed to make a diagnosis, plan and corroborate stent placement, and assess for the presence of possible complications were evaluated by a radiologist or a specialist in the corresponding modality in association with one of the authors (L.P., I.P., H.G.). The follow-up period for each patient varied (range, 5 days to 2 years) and continued until the treatment (with or without stent placement) was concluded or the patient died.


   RESULTS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
 REFERENCES
 
Coated Stent Placement
The complications in the two patients with diverticulitis outweighed the therapeutic outcomes. Two of the four fistulas resolved with stent placement. Three of the four postsurgical stenoses improved with stent placement, although assistance in the form of a series of additional dilations was required. With regard to complications, two stents (for treatment of diverticulitis) resulted in colon perforation (one perforation and one fistula), and two other stents had to be removed because of pain. The results are summarized in the Table.


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  		Patients and Results

 
In the two cases of diverticulitis complicated by pelvic abscess, the coated stents resolved the abscesses, but both patients subsequently developed complications. Patient 1 (Fig 1) was released 1 week after stent placement without symptoms, drainage, or antibiotic treatment, but he was readmitted 5 months later with abdominal pain and severe rectal bleeding that resolved spontaneously without treatment. A barium enema examination revealed the presence of an intestinal fistula, but since the clinical symptoms had resolved and surgery was not an option, the patient was discharged. The patient had continuous diarrhea, spontaneously resolving episodic pain, and pseudo-occlusion of the bowel until he died of myocardial infarction 2 years later.



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  		Figure 1a. Patient 1. (a) Right anterior oblique radiograph obtained from barium enema study performed in 73-year-old man who presented with abdominal pain and fever shows stenosis and spiculation (arrows) of sigmoid colon; these radiologic signs are consistent with a diagnosis of diverticulitis. (b) Transverse nonenhanced CT scan of pelvis shows parasigmoid abscess (A) that was drained with a catheter. (c) Oblique barium enema radiograph. After the abscess persisted for 11/2 months despite drainage and antibiotic therapy, a coated stent (arrowhead) was placed across the affected segment of the sigmoid colon. (d) Transverse nonenhanced CT scan of the pelvis obtained 6 days after stent placement shows resolution of abscess. Note stent (P) position across the affected sigmoid colon segment. (e) Frontal single-contrast barium enema radiograph. Patient was readmitted 5 months later with abdominal pain and rectal bleeding. At colonoscopy, the endoprosthesis was visualized in a crosswise position with one end protruding into the colonic wall. Radiograph shows rapid refilling of small-bowel loops that is probably due to the presence of a fistula in the region of the stent (P). The fistula could not be precisely located, but there was practically no filling of the descending colon (DC) beyond the stent.

 


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  		Figure 1b. Patient 1. (a) Right anterior oblique radiograph obtained from barium enema study performed in 73-year-old man who presented with abdominal pain and fever shows stenosis and spiculation (arrows) of sigmoid colon; these radiologic signs are consistent with a diagnosis of diverticulitis. (b) Transverse nonenhanced CT scan of pelvis shows parasigmoid abscess (A) that was drained with a catheter. (c) Oblique barium enema radiograph. After the abscess persisted for 11/2 months despite drainage and antibiotic therapy, a coated stent (arrowhead) was placed across the affected segment of the sigmoid colon. (d) Transverse nonenhanced CT scan of the pelvis obtained 6 days after stent placement shows resolution of abscess. Note stent (P) position across the affected sigmoid colon segment. (e) Frontal single-contrast barium enema radiograph. Patient was readmitted 5 months later with abdominal pain and rectal bleeding. At colonoscopy, the endoprosthesis was visualized in a crosswise position with one end protruding into the colonic wall. Radiograph shows rapid refilling of small-bowel loops that is probably due to the presence of a fistula in the region of the stent (P). The fistula could not be precisely located, but there was practically no filling of the descending colon (DC) beyond the stent.

 


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  		Figure 1c. Patient 1. (a) Right anterior oblique radiograph obtained from barium enema study performed in 73-year-old man who presented with abdominal pain and fever shows stenosis and spiculation (arrows) of sigmoid colon; these radiologic signs are consistent with a diagnosis of diverticulitis. (b) Transverse nonenhanced CT scan of pelvis shows parasigmoid abscess (A) that was drained with a catheter. (c) Oblique barium enema radiograph. After the abscess persisted for 11/2 months despite drainage and antibiotic therapy, a coated stent (arrowhead) was placed across the affected segment of the sigmoid colon. (d) Transverse nonenhanced CT scan of the pelvis obtained 6 days after stent placement shows resolution of abscess. Note stent (P) position across the affected sigmoid colon segment. (e) Frontal single-contrast barium enema radiograph. Patient was readmitted 5 months later with abdominal pain and rectal bleeding. At colonoscopy, the endoprosthesis was visualized in a crosswise position with one end protruding into the colonic wall. Radiograph shows rapid refilling of small-bowel loops that is probably due to the presence of a fistula in the region of the stent (P). The fistula could not be precisely located, but there was practically no filling of the descending colon (DC) beyond the stent.

 


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  		Figure 1d. Patient 1. (a) Right anterior oblique radiograph obtained from barium enema study performed in 73-year-old man who presented with abdominal pain and fever shows stenosis and spiculation (arrows) of sigmoid colon; these radiologic signs are consistent with a diagnosis of diverticulitis. (b) Transverse nonenhanced CT scan of pelvis shows parasigmoid abscess (A) that was drained with a catheter. (c) Oblique barium enema radiograph. After the abscess persisted for 11/2 months despite drainage and antibiotic therapy, a coated stent (arrowhead) was placed across the affected segment of the sigmoid colon. (d) Transverse nonenhanced CT scan of the pelvis obtained 6 days after stent placement shows resolution of abscess. Note stent (P) position across the affected sigmoid colon segment. (e) Frontal single-contrast barium enema radiograph. Patient was readmitted 5 months later with abdominal pain and rectal bleeding. At colonoscopy, the endoprosthesis was visualized in a crosswise position with one end protruding into the colonic wall. Radiograph shows rapid refilling of small-bowel loops that is probably due to the presence of a fistula in the region of the stent (P). The fistula could not be precisely located, but there was practically no filling of the descending colon (DC) beyond the stent.

 


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  		Figure 1e. Patient 1. (a) Right anterior oblique radiograph obtained from barium enema study performed in 73-year-old man who presented with abdominal pain and fever shows stenosis and spiculation (arrows) of sigmoid colon; these radiologic signs are consistent with a diagnosis of diverticulitis. (b) Transverse nonenhanced CT scan of pelvis shows parasigmoid abscess (A) that was drained with a catheter. (c) Oblique barium enema radiograph. After the abscess persisted for 11/2 months despite drainage and antibiotic therapy, a coated stent (arrowhead) was placed across the affected segment of the sigmoid colon. (d) Transverse nonenhanced CT scan of the pelvis obtained 6 days after stent placement shows resolution of abscess. Note stent (P) position across the affected sigmoid colon segment. (e) Frontal single-contrast barium enema radiograph. Patient was readmitted 5 months later with abdominal pain and rectal bleeding. At colonoscopy, the endoprosthesis was visualized in a crosswise position with one end protruding into the colonic wall. Radiograph shows rapid refilling of small-bowel loops that is probably due to the presence of a fistula in the region of the stent (P). The fistula could not be precisely located, but there was practically no filling of the descending colon (DC) beyond the stent.

 
The second patient with diverticulitis (patient 2) began experiencing abdominal pain 4 days after stent placement, and the pain gradually worsened and was accompanied by peritonism. Emergency surgery eventually was carried out 15 days after stent placement owing to perforation of the bowel. A partial colectomy was performed, but at surgery it was not possible to locate the perforation or establish a relationship between the perforation and the stent.

Two of the four cases of colonic fistula were resolved with stent placement. In patient 3 (Fig 2), a stent was placed 40 days after ileostomy was performed to rest the bowel in an unsuccessful attempt to seal the fistula. Stent placement helped to resolve the fistula clinically and radiologically (cystography performed at 40 days and subsequent barium enema examination) in a matter of weeks. The stent was removed manually 6 months after placement, and the ileostomic fistula was closed.



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  		Figure 2a. Patient 3. (a) Lateral cystogram obtained 40 days after ileostomy in 57-year-old man with a rectovesical fistula after surgery for cancer of sigmoid colon (fistula between rectosigmoid colon anastomosis and neobladder [B] created by using the Studer technique) shows a persisting rectovesical fistula (F) with passage of contrast material. R = rectum. (b) Lateral postvoiding cystogram obtained 40 days after stent (arrowheads) placement in rectum (R) shows the fistula between the neobladder (B) and the rectum is completely sealed. The ileal loop (I) also is shown. Barium enema radiograph (not shown) also showed absence of fistula.

 


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  		Figure 2b. Patient 3. (a) Lateral cystogram obtained 40 days after ileostomy in 57-year-old man with a rectovesical fistula after surgery for cancer of sigmoid colon (fistula between rectosigmoid colon anastomosis and neobladder [B] created by using the Studer technique) shows a persisting rectovesical fistula (F) with passage of contrast material. R = rectum. (b) Lateral postvoiding cystogram obtained 40 days after stent (arrowheads) placement in rectum (R) shows the fistula between the neobladder (B) and the rectum is completely sealed. The ileal loop (I) also is shown. Barium enema radiograph (not shown) also showed absence of fistula.

 
In patient 4, who had a blind fistula (ie, fistula with one end closed) from the descending colon (Fig 3), the symptoms of obstruction resolved immediately, the fever ended, and the radiologic signs of the fistula were practically no longer visible. The patient expelled the stent 6 months after placement. No alterations in the region of the colon where the stent had been placed were observed at the endoscopic examination performed at that time.



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  		Figure 3a. Patient 4. (a) Frontal single-contrast barium enema radiograph obtained in 63-year-old man who had undergone surgery for cancer of descending colon and presented with pain, fever, and inability to defecate shows fistula (extravasation of contrast material [C]) with moderate stenosis (arrows) in region of the surgical anastomosis. (b) Frontal barium enema radiograph obtained 21/2 months after placement of coated stent (arrowhead) shows substantial improvement of fistula. Minimal filling of a small-bowel loop (arrow) is visible; this had not been seen previously and probably was caused by a prolongation of the original fistula.

 


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  		Figure 3b. Patient 4. (a) Frontal single-contrast barium enema radiograph obtained in 63-year-old man who had undergone surgery for cancer of descending colon and presented with pain, fever, and inability to defecate shows fistula (extravasation of contrast material [C]) with moderate stenosis (arrows) in region of the surgical anastomosis. (b) Frontal barium enema radiograph obtained 21/2 months after placement of coated stent (arrowhead) shows substantial improvement of fistula. Minimal filling of a small-bowel loop (arrow) is visible; this had not been seen previously and probably was caused by a prolongation of the original fistula.

 
In patient 5, the stent was expelled 3 days after placement because there was no stenosis associated with the fistula, and the patient underwent reparative surgery. Patient 6, who had a postsurgical rectovaginal fistula (Fig 4), had clinical improvement following stent placement, but barium enema examination revealed that the fistula was still present, and the stent caused the patient intense rectal pain. We left the stent in place for 2 months to allow the fistula to seal, but because of the absence of radiologic changes and persistent pain that failed to resolve with analgesic medication, we removed the stent. Clinical symptoms reappeared, and the patient underwent surgery for repair of the fistula.



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  		Figure 4a. Patient 6. (a) Lateral barium enema radiograph obtained in 60-year-old woman shows rectovaginal fistula with contrast material leakage into vagina (V) and uterus (U) at an end-to-side rectosigmoid colon anastomosis (arrows). (b) Frontal barium enema radiograph shows large diameter of colon in region of fistula (arrowheads) makes it difficult for stent to fit snugly. (c) Lateral barium enema radiograph shows fistula (arrow) persisted despite placement of stent (P) across the anastomosis. Contrast material appears to be flowing between the stent and the colonic wall and thus passing through the fistula.

 


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  		Figure 4b. Patient 6. (a) Lateral barium enema radiograph obtained in 60-year-old woman shows rectovaginal fistula with contrast material leakage into vagina (V) and uterus (U) at an end-to-side rectosigmoid colon anastomosis (arrows). (b) Frontal barium enema radiograph shows large diameter of colon in region of fistula (arrowheads) makes it difficult for stent to fit snugly. (c) Lateral barium enema radiograph shows fistula (arrow) persisted despite placement of stent (P) across the anastomosis. Contrast material appears to be flowing between the stent and the colonic wall and thus passing through the fistula.

 


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  		Figure 4c. Patient 6. (a) Lateral barium enema radiograph obtained in 60-year-old woman shows rectovaginal fistula with contrast material leakage into vagina (V) and uterus (U) at an end-to-side rectosigmoid colon anastomosis (arrows). (b) Frontal barium enema radiograph shows large diameter of colon in region of fistula (arrowheads) makes it difficult for stent to fit snugly. (c) Lateral barium enema radiograph shows fistula (arrow) persisted despite placement of stent (P) across the anastomosis. Contrast material appears to be flowing between the stent and the colonic wall and thus passing through the fistula.

 
Noncoated Stent Placement
In the four patients with postsurgical stenoses (Fig 5), the symptoms of obstruction were relieved immediately after stent placement but recurred a few days after the expulsion or removal of the stents. Patient 7 required placement of both a stent and a coil endoprosthesis, both of which were expelled, and a number of dilations until she became asymptomatic after a year and a half of treatment. Two endoprostheses were also placed in patient 8, who also required a number of dilations before, during, and after stent placement for 2 years before the stricture resolved. Patient 9 could not tolerate the stent: The device caused severe pain and had to be removed 14 days after placement. Clinical symptoms of obstruction recurred 7 days later, and because the dilation procedures were ineffective and the patient had severe pain and evidence at colonoscopy of extensive inflammatory lesions in the sigmoid colon secondary to radiation therapy, colectomy was performed 4 months after the attempted stent placement. Patient 10 received full treatment for postsurgical stricture for 6 months after surgery; his treatment protocol and progress were as follows: several relatively ineffective dilations, stent placement with expulsion 48 hours later, improvement of the stenosis at barium enema examination, recurrence of the obstruction a few days later, additional dilations performed for a week, and final resolution of symptoms.



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  		Figure 5a. Patient 10. (a) Frontal barium enema radiograph obtained in 53-year-old man with bowel obstruction following surgery for diverticulitis shows occlusion (O) at level of rectosigmoid colon anastomosis. (b) Frontal barium enema radiograph shows stent placement at rectosigmoid junction after successful resolution of obstruction. This view of stent across the anastomosis shows narrower expansion (arrows) of the middle third of the rectosigmoid colon due to the effect of the tight stricture. (c) Frontal barium enema radiograph obtained after expulsion of stent 48 hours after placement and resolution of obstruction shows larger diameter (arrows) of anastomosis; however, clinical symptoms of obstruction recurred 1 week later.

 


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  		Figure 5b. Patient 10. (a) Frontal barium enema radiograph obtained in 53-year-old man with bowel obstruction following surgery for diverticulitis shows occlusion (O) at level of rectosigmoid colon anastomosis. (b) Frontal barium enema radiograph shows stent placement at rectosigmoid junction after successful resolution of obstruction. This view of stent across the anastomosis shows narrower expansion (arrows) of the middle third of the rectosigmoid colon due to the effect of the tight stricture. (c) Frontal barium enema radiograph obtained after expulsion of stent 48 hours after placement and resolution of obstruction shows larger diameter (arrows) of anastomosis; however, clinical symptoms of obstruction recurred 1 week later.

 


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  		Figure 5c. Patient 10. (a) Frontal barium enema radiograph obtained in 53-year-old man with bowel obstruction following surgery for diverticulitis shows occlusion (O) at level of rectosigmoid colon anastomosis. (b) Frontal barium enema radiograph shows stent placement at rectosigmoid junction after successful resolution of obstruction. This view of stent across the anastomosis shows narrower expansion (arrows) of the middle third of the rectosigmoid colon due to the effect of the tight stricture. (c) Frontal barium enema radiograph obtained after expulsion of stent 48 hours after placement and resolution of obstruction shows larger diameter (arrows) of anastomosis; however, clinical symptoms of obstruction recurred 1 week later.

 

   DISCUSSION
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
REFERENCES
 
Few experiences with the placement of metallic stents for benign colonic disorders have been reported in the literature. The poor results achieved when treating benign esophageal strictures with stents (15–17) have, not unexpectedly, been repeated when treating colonic stenoses, and, hence, stent use is generally contraindicated. Nevertheless, the colon affords certain possibilities that do not exist for other regions in the digestive tract—namely, surgical resection of the segment in which the stent has been placed in the event of complications and removal of the stent endoscopically or manually to obviate long-term problems, whereby stent placement becomes a temporary treatment. These possibilities may broaden the indications for stent placement in the treatment of benign conditions of the colon.

The method of stent placement for treatment of benign colonic disorders is the same as that used in cases of malignant strictures, but in our experience and in the experience of other colleagues (12–14), because these lesions are located mainly in the rectosigmoid colon (surgical anastomoses), the procedure is simpler than that for lesions located higher in the colon. Conversely, medium- and long-term complications that may be caused by the stent, such as obstruction and perforation, and the risk of migration are more important in patients with benign conditions.

We placed coated stents in two patients with diverticulitis of the sigmoid colon to seal off the microperforations that are present in the wall of the colon in such conditions and that are responsible for the development of parasigmoid abscesses when complications arise. The stents in these two cases were not intended to relieve obstruction and were effective in that within just a few days they were able to "dry out" collections that had persisted for weeks or months despite treatment with antibiotics and percutaneous drainage. Nevertheless, complications occurred in both cases: a fistula in one patient and bowel perforation in the other. Although it could not be shown that the endoprosthesis was the cause of the perforation, it seems to us that the risk of perforation is greater when metallic stents are placed in colonic segments that exhibit acute inflammation and hence a more friable wall.

The literature contains reports (21,22) on the use of stents in four cases of diverticulitis, although the purpose of those interventions was to relieve obstruction prior to surgery. The stent remained in place permanently in only one of these four cases; the patient refused to undergo surgery at resolution of the episode of acute inflammation. However, the report contains no information on the patients’ long-term progress or on whether there were any stent-related complications (22). On the basis of our experience—although two cases may not be representative—it is our opinion that diverticulitis is not a good indication for the placement of permanent metallic stents as opposed to the placement of temporary presurgical stents. Stents are not an alternative to surgery in patients who are not candidates for surgery because they may make emergency surgery necessary. They should be regarded as only a last resort in exceptional cases when no other therapeutic options are available.

Anastomotic fistulas of the colon occur more frequently in anastomoses in lower regions and are managed conservatively with or without ileostomy or reparative surgery, depending on the case. Stents, coated ones in particular, may represent a therapeutic alternative, as they have in cases of esophageal fistulas of various causes (25–27). Still, the usefulness of stents depends not only on whether they are coated but also on other factors (28). In this respect, the presence of stenosis associated with the fistula and the fistula size are two factors that need to be taken into account.

In our study, stenosis was observed to be instrumental in preventing stent migration. On the other hand, stenosis may be the basic problem that needs to be resolved, because the persistence of a fistula may depend on the presence of obstruction distal to the fistula location. Relieving the obstruction—that is, eliminating retrograde stasis—may be more important in sealing a fistula than actually placing the stent across the opening of the fistula; thus, a noncoated stent may be just as effective as a coated stent (23,29). Furthermore, the close fit of the stent to the fistulized wall and the effect of the pressure exerted on the wall by the stent are of great importance in sealing the leak (28,29). Fistula size also is a factor: If the fistula is large, it will not be sealed, even when a coated stent is used.

In patient 5, the therapeutic failure of the stent was due to the absence of stenosis and the resulting stent migration, and in patient 6, it was due to the failure of the stent to fit snugly against the colonic wall and to the large size of the fistula.

Literature reports on colonic fistulas treated by means of stent placement have focused more on neoplastic fistulas (29,30) and less on anastomotic fistulas (23,24). Both coated and noncoated stents have been used, but therapeutic success in the cases reported has depended more on the resolution of the stricture and the avoidance of stent migration than on whether the stents were coated.

Anastomotic stenoses of the rectosigmoid colon that fail to respond to dilation are the most apt benign indication for stent placement. Endoprostheses may have a more lasting dilating effect than balloons or endoscopic bougies, and the ease of recovering the stent when it has fulfilled its purpose makes treatment virtually risk free. However, in our four cases of this type, a number of dilations plus one or two endoprostheses were required, and treatment of the stenosis lasted for months or years. We observed the decompressive effect of the prosthesis to be somewhat longer lasting than that of dilation, but usually it was not permanent. In our experience, the stent tended to migrate once the stenosis had widened to a diameter at which it could no longer hold the prosthesis in place, and this phenomenon was followed by a recurrence of the clinical symptoms a few days later, which necessitated a series of interventions in these patients. Conversely, in two cases reported in the literature, the stents were effective and did not migrate during 8 months of follow-up in one case of anastomotic stenosis (18) or during the 6 months that the patient survived in one case of ischemic colitis (25); the cause of death in the latter case was an aortoenteric fistula.

Our experiences with the problems associated with long-term colonic stent placement for those stents that were not expelled or removed were limited but adverse: Two cases of diverticulitis treated with stent placement resulted in perforation of the colonic wall. To our knowledge, the literature contains only four such cases: One case was that of stenosis associated with diverticulitis; no follow-up is described (22). In another case, that of ischemic stenosis, the patient died of an aortoenteric fistula after 6 months, and there is no mention of whether the fistula was stent related (25). In another case, a neoplastic fistula of the sigmoid colon resolved with stent placement, but the patient developed another fistula before dying; again, there is no mention of whether the last fistula was stent related (23). The last case is that of an anastomotic stenosis treated with stent placement; eight trouble-free months followed (18). No positive conclusions about the use of prostheses as a final therapeutic measure can be drawn from these limited experiences.

In conclusion, metallic stents may represent a treatment option for certain benign conditions of the colon. Stents are most useful in cases of stricture, with their effectiveness in the treatment of fistulas seemingly being dependent on the presence of stenosis. Acute inflammation in the colonic segment where the prosthesis is to be placed should be considered a contraindication to stent use; however, the possibility of subsequently removing the stent might be a factor in favor of placement. Generally, the metallic stents that are currently available for use in the colon do not represent a viable alternative for final treatment in patients with normal life expectancies and seem to be suitable only for consideration as a temporary treatment in the absence of other therapeutic alternatives.


   FOOTNOTES
 
Author contributions: Guarantor of integrity of entire study, L.P.; study concepts, all authors; study design, L.P., I.P., H.G.; literature research, L.P., I.P., H.G.; clinical studies, L.P., I.P., H.G., R.F.L.; data acquisition, all authors; data analysis/interpretation, L.P., R.F.L.; manuscript preparation and definition of intellectual content, L.P.; manuscript editing, L.P., I.P.; manuscript revision/review and final version approval, all authors.


   REFERENCES
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
 REFERENCES
 

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