AJR 2000; 175:1631-1637
© American Roentgen Ray Society
Malignant Colonic Obstruction Due to Extrinsic Tumor
Palliative Treatment with a Self-Expanding Nitinol Stent
Shiro Miyayama1,
Osamu Matsui2,
Koichi Kifune1,
Masashi Yamashiro1,
Toru Yamamoto1,
Kiyohide Kitagawa3,
Yoshio Kasahara4,
Yasuyuki Asada4,
Yoshiro Iida4 and
Shoji Miura4
1
Department of Diagnostic Radiology, Fukuiken Saiseikai Hospital, 7-1,
Funabashi, Wadanaka-cho, Fukui 918-8503, Japan.
2
Department of Radiology, Kanazawa University Hospital, 13-1, Takara-machi,
Kanazawa 920-8641, Japan.
3
Department of Radiology, Koseiren Takaoka Hospital, 5-10, Eiraku-cho, Takaoka
933-8555, Japan.
4
Department of Surgery, Fukuiken Saiseikai Hospital, 7-1, Funabashi,
Wadanaka-cho, Fukui 918-8503, Japan.
Received April 4, 2000;
accepted after revision May 22, 2000.
Address correspondence to S. Miyayama.
Abstract
OBJECTIVE. The purpose of this study was to evaluate the usefulness
of self-expanding nitinol stents for palliative treatment of malignant
colorectal obstruction caused by unresectable extrinsic tumor, colorectal
metastasis, or peritoneal seeding.
SUBJECTS AND METHODS. One covered stent and 10 uncovered stents were
deployed in eight patients with colorectal obstruction due to extrinsic tumor
under fluoroscopic guidance. The sites of obstruction were located in the
rectum (n = 5), in the rectosigmoid colon (n = 2), and from
the transverse colon to the descending colon (n = 1). Clinical
usefulness and complications were analyzed.
RESULTS. Stents were placed successfully in all patients. Minor
modifications of the delivery system were required in the tortuous
rectosigmoid and lower rectum strictures. Symptoms of obstruction were
initially resolved in all but one patient. In that patient, the presence of
other points of obstruction was suspected. Bowel obstruction recurred in two
patients: one obstruction was due to migration of a covered stent 4 days after
the procedure, and the other obstruction was due to peritoneal seeding 33 days
after the procedure. Both required colostomy or ileostomy. All patients died
12-111 days after stent placement (mean, 56 days). In five patients (63%),
colonic obstruction was palliated by placing a stent until the patients' death
between 39 and 111 days after stent placement (mean, 62 days). Six
complications occurred in four patients and included stent migration
(n = 1), anal bleeding (n = 2), anal pain that required
analgesia (n = 1), and fever (n = 2).
CONCLUSION. This self-expandable nitinol stent adequately palliated
63% of patients with colonic obstruction due to extrinsic tumor in this small
series. Patient selection is very important to the success of this
treatment.
Introduction
Acute colonic obstruction is a severe complication of primary colorectal
carcinoma and usually necessitates rapid intervention because patients rapidly
develop a poor general condition of dehydration and electrolyte imbalance
[1]. Emergency surgical
treatment has been performed in patients with this condition; however, the
mortality rate is relatively high
[2,3,4].
A new technique was developed to treat colonic obstruction by placing a
metallic stent
[1,2,3,4,5].
Previously, it was used mainly as a preoperative treatment of colorectal
carcinoma to facilitate primary anastomosis and to avoid colostomy
[5,6,7,8,9,10,11,12].
Colonic obstruction due to peritoneal metastasis or direct invasion from
other abdominal malignancies also occurs. For this obstruction, palliative
decompressive colostomy has been the only therapeutic option; however, it
reduces the quality of life of the patient, who has a short life expectancy.
To our knowledge, only a few patients with colorectal obstruction due to
extrinsic tumor have undergone treatment for palliation with metallic stents
[9,
11]
We used self-expandable nitinol stents to avoid colostomy in eight patients
with colorectal obstruction due to unresectable extrinsic tumor, colorectal
metastasis, or peritoneal seeding.
Subjects and Methods
Patients
Between October 1997 and February 2000, malignant colorectal obstructions
caused by colorectal metastasis or peritoneal seeding in eight patients were
treated with self-expandable nitinol stents. The diagnosis of an extrinsic
colorectal tumor was established on the basis of radiologic and endoscopic
findings, in addition to the clinical histories of the patients. We selected
these patients from 17 patients with secondary malignant colonic obstruction
who underwent imaging evaluation during the same period. Stent placement was
indicated only if points of colorectal obstruction distal to the splenic
flexure were suspected. When points of obstruction proximal to the splenic
flexure or noncolonic obstruction were revealed on CT scans, surgical
intervention was recommended instead of stent placement. There were five men
and three women (age range, 38-76 years; mean age, 61 years)
(Table 1). Informed consent was
obtained from each patient.
Of the eight patients, five had recurrent malignant tumors after surgical
resection (gastric carcinoma, n = 2; rectal carcinoma, n =
1; bladder carcinoma, n = 1; uterine cervical carcinoma, n =
1) with colorectal metastasis or peritoneal metastasis. Two patients had
rectosigmoid metastasis from unresectable advanced gastric carcinoma, and one
patient had multiple liver metastasis and peritoneal carcinomatosis due to
adenocarcinoma from an unknown origin. Five patients had malignant ascites.
Two patients with recurrent gastric carcinoma and one patient with recurrent
uterine cervical carcinoma presented with bilateral hydronephrosis caused by
retroperitoneal metastasis and were treated with placement of double-pigtail
ureteral stents during the same period.
The diagnosis of colonic obstruction was confirmed by means of abdominal
radiography, CT, colonoscopy, and barium enema or enema with water-soluble
contrast material. Radiography, CT, and barium enema or enema with
water-soluble contrast material were performed in all eight patients.
Colonoscopy was performed in all but one patient who had previously undergone
tumor resection and colostomy for rectal carcinoma (Miles' operation). The
colonoscope could not pass the obstructed segment in any patient.
The sites of obstruction were located in the rectum (n = 5), in
the rectosigmoid colon (n = 2), and from the transverse colon to the
descending colon (n = 1). The patient with the obstruction from the
transverse colon to the descending colon had previously been treated with
Miles' operation.
Procedure
Stent placement was performed under fluoroscopic guidance. In seven
patients, it was performed via the anus. In the remaining patient, who had
previously undergone the Miles' operation, it was performed via the colostomy.
Before the procedure, 15 mg of pentazocine (Pentagin; Sankyo, Tokyo, Japan)
was IV administered for pain relief. A 5-French angiographic catheter (Terumo,
Tokyo, Japan) was inserted into the anal side of the stricture, and the distal
end of the obstructed segment was confirmed with diluted water-soluble
contrast material (Gastrografin; Schering, Berlin, Germany) injected through
the catheter. A 150-cm-long 0.035-inch guidewire (Radifocus M; Terumo) was
then advanced across the stricture. After the stricture was successfully
negotiated with the angiography catheter, the guidewire was removed and
contrast material was injected to confirm the proximal end of the obstructed
segment. After colonic perforation was ruled out, a 260-cm-long 0.038-inch
guidewire (Zebra; Microvasive/Boston Scientific, Natick, MA) was advanced via
the angiographic catheter to facilitate advancement of the stent delivery
system.
Self-expanding nitinol stents (Ultraflex; Microvasive/Boston Scientific)
designed for use in the esophagus, with diameters of 17-23 mm at the barrel
and lengths of 10-15 cm, were used in all patients. Uncovered stents were used
except for the first case. The stent was knitted 0.15-inch nitinol wire and
had a single flared end with or without a cover. The covered stent had a layer
of translucent polyurethane that covered the mid section of the stent. The
stent was mounted on a 16-French delivery catheter by means of a crocheted
suture cord. Retracting the suture gradually deployed the stent. For the
proximal release system, which was used in the present study, the suture
unraveled from the leading stent end first. The length of the lesions was
determined with barium enema or enema with water-soluble contrast material
performed before the procedure, and, in cases with tortuous strictures, the
length of the stricture was also evaluated by means of a 0.035-inch guidewire
with marker bands (Magic Torque; Medi-Tech/Boston Scientific) during the
procedure. A stent at least 2 cm longer than the stricture was selected. Two
stents were deployed coaxially in three patients with 14- to 18-cm-long
obstructions. Balloon dilatation of the stricture was performed if the
delivery system could not advance across the obstructed segment. In one
patient, we attached a 0.1-mm-thick vinyl membrane (Achilles, Tokyo, Japan)
outside the delivery system by means of a suture to reduce the friction
(Fig. 1). The vinyl membrane
was released from the delivery catheter by pulling the suture, and it was
retracted before deployment of the stent. After stent placement, the delivery
system was exchanged over the wire for the angiography catheter, and contrast
material was injected to check the stent positioning and patency and to
evaluate perforation of the colon.
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Fig. 1. —Photograph shows stent (Ultraflex; Microvasive/Boston
Scientific, Natick, MA) wrapped with 0.1-mm-thick vinyl membrane (Achilles,
Tokyo, Japan) outside delivery system. Arrowheads indicate sutures that attach
membrane. Olive tip of delivery system has been removed. Scale is in
centimeters.
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Follow-up abdominal radiographs were obtained within 3 days after the
procedure to evaluate the expansion and migration of the stent and the extent
of residual, if any, colonic obstruction. In three patients, endoscopy was
performed after 3-23 days (mean, 14 days) to evaluate stent patency and to
observe the colonic mucosa of the stented segment.
We defined technical success as accurate placement of the stent in the
target position and opening of the stricture to resolve the bowel obstruction.
We analyzed the technical success rate of stent placement and the occurrence
of procedure-associated complications.
Results
Stents were placed in all patients
(Table 1). In one patient with
a colostomy who had undergone Miles' operation, two stents were placed tandem
via the colostomy (Fig.
2A,2B,2C).
Balloon dilatation was required in four patients to advance the stent delivery
system. We encountered difficulties placing stents in two conditions, and
minor modifications of the stent delivery system were required. In one patient
with tight and tortuous stricture of the rectosigmoid colon, it was impossible
to advance the delivery system through the obstructed segment despite balloon
dilatation. The cause of the failure was thought to be the high resistance of
the corrugated surface of the delivery system. Therefore, we covered the
delivery system with a 0.1-mm vinyl membrane to reduce the friction. After
this modification, the delivery system could be advanced easily across the
stricture, the coated vinyl membrane was removed, and the stent was deployed
successfully. In one patient with an obstruction in the lower rectum, the
trailing end of the unexpanded stent was located outside of the anus when the
delivery system was placed at the target position. The stent was not released
because it was unclear whether the flared end of the stent would enter into
the rectum through the anus. We untied 3-5 ties of the crocheted suture cord
around the stent and pushed up the trailing end of the unexpanded stent with a
split 24-French sheath (Fig.
3). After this modification, the distance from the metal marker
indicated the trailing end of the expanded stent to the trailing end of the
unexpanded stent was short enough (approximately 2 cm of the 15-cm-long stent)
to enter the rectum, and the stent could be placed easily (Fig.
4A,4B).
After we treated this patient, we routinely used the same modification of the
delivery system in the lower rectum, although the trailing end of the stent
was pushed up by hand without the sheath in the last two patients.
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Fig. 2A. —61-year-old man with recurrent rectal carcinoma treated
previously with Miles' operation. CT scan shows huge peritoneal mass
surrounding descending colon (arrow). Note right hydronephrosis.
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Fig. 2B. —61-year-old man with recurrent rectal carcinoma treated
previously with Miles' operation. Spot radiograph obtained after injection of
water-soluble contrast medium through catheter inserted into proximal side of
stricture reveals 18-cm-long stricture from splenic flexure to descending
colon.
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Fig. 2C. —61-year-old man with recurrent rectal carcinoma treated
previously with Miles' operation. Spot radiograph, obtained after placing two
uncovered stents (one 18 mm in diameter and 15 cm long, and one 18 mm in
diameter and 10 cm long) tandem, reveals good patency of stents.
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Fig. 3. —Photograph shows 15-cm-long stent (Ultraflex;
Microvasive/Boston Scientific, Natick, MA) pushing up distal end of stent with
split sheath. Olive tip of delivery system has been removed. Scale is in
centimeters. Arrows indicate trailing end of unexpanded stent, and arrowheads
indicate metal marker and trailing end of expanded stent.
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Fig. 4A. —76-year-old man with rectal metastasis from unresectable
gastric carcinoma. Spot radiograph obtained during barium enema in lateral
position shows 12-cm-long tight and irregular stricture in lower rectum.
Stricture extends about 5 cm above anal verge.
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Fig. 4B. —76-year-old man with rectal metastasis from unresectable
gastric carcinoma. Spot radiograph obtained after placing uncovered stent (18
mm in diameter and 15 cm long) shows good patency of stent.
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The implanted stent was fully expanded on abdominal radiographs obtained 3
days after stent placement in all patients. Large-bowel obstructions were
initially palliated in seven (88%) of eight patients. Clinical and
radiographic findings were relieved 1-3 days after stent placement. In the
remaining patient with recurrent uterine carcinoma, the patient could excrete
small amounts of stool after stent placement, but bowel obstruction was not
relieved. The presence of other points of obstruction above the stented
segment was suspected; however, a second diagnostic enema was not performed
because of the poor general condition of the patient. The patient died 12 days
after stent placement. Bowel obstruction recurred in two patients. In one
patient with peritoneal carcinomatosis from unknown origin who underwent
placement of a 17-mm covered stent in the rectum, the stent migrated downward
4 days after the procedure, and bowel obstruction recurred. The patient
underwent palliative colostomy and the migrated stent was removed during
surgery, but the patient died 14 days after stent placement. In the remaining
patient, with recurrent gastric carcinoma, bowel obstruction recurred 33 days
after stent placement. Laparotomy showed ileal obstruction due to a peritoneal
mass, and ileostomy was performed. Stent obstruction due to stool impaction,
mucosal prolapse, or tumor ingrowth was not observed in any patient.
Follow-up endoscopy showed that the stricture was widely opened and the
mucosa in the stented segment was not invaded by tumor (Figs.
5A,5B
and
6A,6B).
Most of the wire mesh of the stent was embedded in the wall even on endoscopy
performed 3 days after stent placement (Fig.
5A,5B).
The mucosa was slightly red in the stented segment in one patient with
recurrent bladder carcinoma. Ulcer formation by the stent was observed in the
patient with recurrent gastric carcinoma who presented with anal pain and
bleeding (Fig.
6A,6B).
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Fig. 5B. —38-year-old-woman with rectosigmoid metastasis from recurrent
gastric carcinoma. Colonoscopic image obtained 3 days after stent placement
shows wide opening of stricture and embedding of wire mesh.
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Anal bleeding developed in two patients. One patient, with recurrent
bladder carcinoma, had an 18-mm stent placed in the rectum but exhibited a
small amount of anal bleeding 5 hr after stent placement. The hemorrhage was
managed conservatively, and the patient experienced no recurrent bleeding. The
other patient, with recurrent gastric carcinoma, had a 23-mm stent placed in
the rectum but complained of anal pain and experienced bleeding due to ulcer
formation 23 days after stent placement. The hemorrhage was managed
conservatively, but it recurred 34 days after stent placement. A total of 6
units of blood transfusion were necessary in this patient. Anal pain was
treated with morphine sulfate, which was continued until the patient's death
45 days after stent placement. Two patients registered a fever of up to
38°C for 5-7 days, which was managed conservatively.
All patients died between 12 and 111 days (mean, 56 days) after stent
placement. The mean survival duration, excluding the patient with stent
migration and the one with unsuccessful management of bowel obstruction, was
70 days. In five patients (63%), bowel obstruction was successfully managed by
stent placement, and these patients died 39-111 days after stent placement
(mean, 62 days). All patients whose bowel obstruction was successfully managed
by stent placement and the patient who subsequently underwent ileostomy died
of diffuse metastasis and cachexia.
Discussion
Metallic stent placement has been performed primarily in patients with
obstructing carcinoma of the left colon to reduce the need for emergency
colostomy. Some authors reported that the procedure could convert a surgical
emergency to elective surgery and two-stage surgery to one-stage surgery
[5,6,7,8,9,10,11,12].
Additionally, palliative stent placement for patients for whom resection is
not possible has become an acceptable procedure
[6,
8,
11,
12]. Stent placement appears
to be a simple and effective procedure, and it may quickly improve the poor
general condition of a patient with colonic obstruction.
Various kinds of covered and uncovered metallic stents have been used in
the gastrointestinal tract
[13,14,15,16,17,18,19].
Recently, a stent has been marketed specifically for use in the colon. Because
colonic stricture can be relatively tortuous and the colonic wall is thinner
and weaker than that of the esophagus or stomach, we used an Ultraflex stent
in our study. The Ultraflex stent was selected because it has a high degree of
longitudinal flexibility, and its edges appear to be less jagged compared with
those of a Wallstent (Boston Scientific) or a
Gianturco-Rösch Z-stent (Cook, Bloomington, IN).
For palliative stent placement, the implanted stent is not generally removed;
therefore, pressure necrosis at the stent edge may occur if a less flexible
stent is used [7]. However, the
configuration of this stent appears somewhat unsuitable for use in the colon.
The flare end lies distal to the colonic obstruction because it is designed
for use in the esophagus [13].
A better fixation of the stent may be achieved in the colon if both ends are
flared.
We encountered two major technical problems during stent placement. First,
the delivery system could not pass the tight and tortuous stricture because
the corrugated surface of the suture-covered stent created high resistance.
Wrapping the delivery system with a thin vinyl membrane to reduce the friction
solved this problem. Johnson et al.
[12] reported the usefulness
of an endotracheal tube as a catheter conduit. The stent could be placed less
traumatically without balloon dilatation if the sheath or the retrievable
membrane covered the corrugated surface of the mounted stent. Second, the
distal end of the unexpanded stent was located outside of the anus when placed
in the lower rectum. Pushing up the distal end of the unexpanded stent may
solve this problem.
Covered metallic stents are mainly used in the gastroesophageal tract
[14,15,16,17,18,19].
They have some advantages over uncovered stents. A covered stent prevents
tumor ingrowth and can seal a fistula
[11,
14,15,16,
18,
19]. Also, a fully covered
stent without barbs is retrievable because it does not embed into the wall
[14,
15,
17]. The disadvantage of a
covered metallic stent is that the risk of stent migration is high
[14,
15,
18]. A covered metallic stent
placed in the colon tends to migrate more frequently than one placed in the
esophagus. Choo et al. [11]
reported that four of eight fully covered stents migrated 3 or 4 days after
placement. They also reported that 11 covered stents with a proximal uncovered
portion did not migrate during their observation period
[11]. In the present study,
one covered Ultraflex stent (with uncovered portions at both ends of the
stent) migrated downward 4 days after placement. This finding suggests that a
covered stent tends to migrate if used for extrinsic compression because the
mucosa at the stented segment is relatively smooth. After stent migration was
observed in the first patient who underwent placement of a covered stent, we
used uncovered stents in the next seven patients, and no further stent
migration occurred. Rey et al.
[6] reported that uncovered
metallic stents used for palliation of unresectable primary colorectal
carcinoma were easily occluded because of tumor ingrowth through the wire.
They hypothesized that extrinsic lesions might give better results than
proliferative intraluminal carcinoma. The present findings suggest that
uncovered stents placed in the extrinsic compression are rarely occluded by
tumor ingrowth because of the absence of massive intraluminal tumors. Stent
occlusion was not observed in any patient. These findings show that an
uncovered stent may be suitable for colorectal obstructions caused by
extrinsic tumors.
The prognosis of patients with colorectal obstruction caused by extrinsic
tumors is poor because of the advanced stage of their tumors. Surgical risk is
also high because of the poor general condition of these patients. Although
life expectancy of patients with extrinsic compression of the colon is short,
we believe that stent placement is useful to avoid colostomy. However,
patients with widespread peritoneal seeding often have multiple bowel
stenoses. In our study, stent placement was indicated in 47% of patients with
secondary colonic obstruction; however, bowel obstruction was not relieved in
one patient who probably had other points of obstruction. It is extremely
important to evaluate patients using radiologic studies, including CT scans,
to exclude other points of obstruction. If other points of colonic stenoses
distal to the splenic flexure or noncolonic stenoses are revealed, surgical or
palliative treatment should be recommended. The complications related to stent
placement appear to be acceptable, except for migration of the stent. Colonic
perforation due to procedural manipulation during stent placement or pressure
necrosis after stent placement was not observed in any of the eight patients
in our study.
Although the number of patients treated in the present study was small and
further studies are required, stent placement is effective palliation in
selected patients with colorectal obstruction caused by extrinsic tumors. The
present findings suggest that uncovered Ultraflex stents appear to be suitable
for use in colonic obstructions caused by extrinsic tumors because of their
excellent flexibility, less traumatic configuration, and low risk of
migration. However, modifications of the stent and the delivery system design
for use in the colon may be necessary.
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Abstract
Introduction
