Use of Dual Knife for Large Pedunculated Colorectal Polyps
Yang, Chia-Wei MD*; Yen, Hsu-Heng MD*,†;
Chen, Yang-Yuan MD‡; Soon, Maw-Soan MD*
Department of Gastroenterology, Changhua Christian Hospital,
Changhua
†School of Medicine, Chung-Shan Medical University, Taichung City
‡Department of Gastroenterology, China Medical University Hospital,
Taichung City, Taiwan
Abstract :
Background: Endoscopic resection of large pedunculated colorectal polyps is
technically difficult, especially when the polyps are so large that it is either not
possible or too difficult to resect them using a conventional polypectomy snare.
Aim: To facilitate the removal of pedunculated colorectal polyps, we developed a
new technique using a combination of a dual knife and preventive hemostatic
procedures.
Methods: Nine patients (5 men and 4 women; mean age, 59.8 y; range, 49 to 79 y)
with pedunculated polyps >2 cm in diameter were treated with this technique. A
dual knife and endoclips or an endoloop were used as needed.
Results: All lesions, except for 1 polyp, were resected endoscopically. The mean
time for complete resection was 8.5 minutes (range, 1.5 to 16 min). The procedure
time decreased significantly after the fifth case (168 vs. 746 s, P=0.0009). No
hemorrhage, perforation, or other complications occurred during follow-up among
the endoscopically resected cases.
Conclusions: Combined use of a dual knife and prophylactic hemostatic
procedures is a feasible alternative technique for removing large pedunculated
colorectal polyps when conventional snare resection is impossible or difficult.
Endoscopic polypectomy is an established procedure for resecting colorectal
polyps, which can also prevent colorectal cancer.1 The use of a conventional
diathermic snare is limited for en bloc resection when the polyp diameter is nearly
equal to or larger than the diameter of the snare. Piecemeal snaring of a large
pedunculated colonic polyp is an alternative technique.2,3 However, this option may
be unacceptable because of the increased risk of bleeding and the inability to
conduct adequate pathologic examinations in cases of suspected malignancy.4
The removal of large or lumen-occupying pedunculated colonic polyps is a great
challenge for endoscopists and the patient might require referral for surgical
management. We previously reported our first experience with using a dual knife to
remove 1 such lesion and found it to be useful and safe.5 Here we describe our
subsequent experience in the endoscopic management of large pedunculated
colonic polyps using this novel technique and evaluate the safety, efficacy,
complications, and limitations of this technique.
PATIENTS AND METHODS
Patients
A retrospective analysis of the endoscopy database identified 9 patients (5 men and
4 women; mean age, 59.8 y; range, 49 to 79 y) with 9 pedunculated colonic polyps
over a 15-month period (July 2010 to November 2011) were included in this study.
The diameters of their polyps were >=2 cm as measured using open biopsy forceps.
These polyps were evaluated by both authors (H.-H. Y and C.-W. Y) who had
experience with performing >500 colonoscopies per year for 5 years. They
determined that a 1-step resection using a standard snare resection technique was
not possible.
Standard piecemeal resection or alternative dual knife–assisted resections were
discussed with the patients before enrollment into this study. The study was carried
out in accordance with the Helsinki Declaration. Written informed consent was
obtained from all patients for the procedures that were performed. Patients
receiving anticoagulant or antiplatelet therapy for cardiovascular diseases were
instructed to discontinue the use of these drugs at least 5 days before the
endoscopic procedure after consultations with a cardiologist and hematologist. Their
medications were resumed if there were no signs of bleeding within 1 day of
resection. Patients on hemodialysis were managed with heparin-free dialysis for 1
week before and after resection. All patients were evaluated for their coagulation
profiles, including complete blood count, prothrombin time, and activated partial
thromboplastin time.
Techniques and Equipment
The cleansing of the bowel was performed by ingestion of a polyethylene glycol
electrolyte lavage solution. After this, all patients received conscious sedation by
administration of midazolam (2 to 5 mg) and meperidine (25 to 50 mg). To facilitate
manipulation of the dual knife for colonic polyp resection, endoscopy was performed
using a gastroscope (GIF-H260; Olympus, Tokyo, Japan) for a distal site of the colonic
polyp or a colonscope (PCF-Q260JL; Olympus) for a proximal site of the colonic polyp.
To safely resect the polyp, prophylactic hemostatic procedures were applied before
the resection, such as those using Endoclips (HX-600-135; Olympus) or a detachable
Endoloop (MAJ-254; Olympus). If possible, we preferred using the endoloop over a
polyp stalk with an estimated diameter of >1 cm because of its greater efficacy in
achieving hemostasis and the technical difficulties involved in applying >2 hemoclips.
The endoloop was placed and tightened until a cyanotic change in the polyp
suggested adequate blockage of blood flow.
For polyp resection, we used a Dual Knife (KD-650U; Olympus; Fig. 1) with an
electrosurgical generator (endocut=50 W; coagulation 30 W; effect 2; ICC=200; ERBE
Co., Tubingen, Germany). The knife length was 1.5 mm. The knife could be fixed in
either an extended position for cutting the stalk above the ligation position by at
least 3 mm under direct visualization or in a retracted position for coagulation when
resection-related bleeding was encountered (Figs. 2–4). The procedure time
recorded the interval between the passage of the Dual Knife through the working
channel and stopped after complete resection of the polyp.
The technique for using the dual knife for resecting the stalk, similar to using a
needle knife, initially involves moving from the lateral side to the central area parallel
to the bowel wall where the polyp is located. If needed, although not routinely
recommended because of the risk of bowel wall injury behind the stalk, the knife can
be pushed onto the stalk while carefully cutting from the proximal part forward to
the distal part. This cutting forward maneuver should only be applied when a thick
stalk is encountered, and should be performed more cautiously when using a needle
knife because of the long knife tip (4 to 7 mm) of commercial devices compared with
the Dual Knife [1.5 mm of model KD-650 Q/U used for esophageal and colorectal
endoscopic submucosal dissection (ESD) and 2 mm of model KD-650 L used for
gastric ESD]. This makes it difficult to control the knife accurately, especially in a
narrow space. We use the dual knife in its retracted position with 0.3 mm of its
needle tip exposed for coagulation to avoid excessive bowel wall injury.
After resection, the polyp was captured using a basket catheter, and if possible,
gently extracted through the anus or dragged to the rectum for spontaneous passage.
We measured the absolute maximum diameter of the polyp head and stalk after its
retrieval or spontaneous passage.
Histologic Examination
Polyps were fixed in 10% formalin and then stained with hematoxylin and eosin for
histopathologic assessment. Colorectal adenomas were histologically classified
according to the World Health Organization Classification of Tumors.6 If cancer was
detected, a decision for further aggressive surgical management was taken based on
the level of cancer invasion. According to Haggitt classification,7 pedunculated polyps
with carcinoma invading the head, neck, or stalk require no further treatment when
the resection margins are free of cancer and there is no lymphatic or vascular
invasion.
Additional radical surgery was reserved for those polyps with carcinoma that had
invaded into the submucosa of the bowel wall below the polyp stalk because of an
increased risk of lymph node metastases.
Follow-up Evaluation
If no complications occurred after the endoscopic procedure, the patients were
discharged with a scheduled follow-up of at least 1 telephone contact within 3 days
and a return to our outpatient services 1 week later. According to our institutional
guideline, patients with malignant polyp without the need for surgery were
scheduled for a follow-up colonoscopy 1 and 6 months later. For patients with
adenomas >1 cm, a follow-up colonoscopy was scheduled 6 months later.
RESULTS
The clinical outcomes of our 9 patients are summarized in Table 1. All 9 polyps were
>2 cm in diameter; the largest was 4 cm in diameter. The stalk diameters were at
least 0.8 cm, with a greatest width of 2.5 cm. The locations were most often over the
sigmoid colon (5/9 polyps), and the others were in the splenic flexure, the
descending colon, and the cecum. The mean time for complete resection after
applying the endoloop or endoclips was 8.5 minutes (range, 1.5 to 16 min).
Resection failed for 1 patient (case 4). This was due to insufficient tightening of the
endoloop because of the limited space for observation in the splenic flexure owing to
the large polyp and wide stalk. Active bleeding was observed after the first resection
attempt, and this patient was referred for surgical resection. The procedure time
decreased significantly after the fifth case (first 4 resected cases vs. last resected
cases: 746 vs. 168 s, P=0.0009).
All polyps were adenomas; 4 patients had carcinomas arising in tubulovillous
adenomas. These carcinomas were confined to the polyp head or stalk and their
resection margins were free of cancer, thereby not requiring any further surgery. All
patients who received complete endoscopic management had no delayed
hemorrhage, perforation, or other complications for at least 3 months. The results
are summarized in Table 1.
DISCUSSION
When faced with pedunculated colonic polyps that are difficult to resect by
maneuvering a conventional diathermic snare because of an occluded lumen or a
polyp head size larger than the snare, stalk resection using a specialized device is an
alternative technique. To remove these lesions en bloc, reported resection
techniques include using a needle knife,8–10 an insulated-tip diathermy knife,11 or a
grasping-type scissors forceps.12 In this study; we report the use of a dual knife as an
alternative technique to remove large pedunculated colorectal polyps.
The dual knife, a recently developed instrument for ESD,13 resembles a short needle
knife with a knob-shaped tip. The small knob-shaped tip is useful for marking and for
hemostasis in its retracted position. This feature makes the needle less likely to slip
during resection of floppy polyps in its extended position. This results in improved
overall knife maneuverability compared with a standard needle knife. In addition,
polyps with wide stalks take more time to be resected, and removal of a floppy
pedunculated polyp is more technically demanding. A large polyp with a long stalk
(our cases 2 and 3) may move relatively freely within the lumen, making it difficult to
control the knife during resection. In this situation, using gravity by a position change
or placing a transparent cap on the scope can help to control the position of the
polyp stalk to facilitate polyp resection. With the increased experience, the
procedure time was reduced from 746 to 168 seconds (P=0.0009) after the fourth
successful case. Therefore, our study suggested this new technique is feasible with a
short learning curve.
The main complication with conventional polypectomy is bleeding, ranging from
0.3% to 6.1% of cases, depending on the polyp size, its location, and whether it has a
broad base or a wide stalk.14 Therefore, prophylactic hemostatic procedures are
required to prevent postpolypectomy hemorrhage. Mechanical hemostatic devices,
such as the endoloop 15,16 and endoclips,8–10 have been introduced for preventing
early or delayed postpolypectomy hemorrhage. The endoloop, measuring 5×3 cm
when fully opened, is maneuvered around the tip of the polyp with limited
expansible force because of its thin nylon composition. It may be a challenge to fully
open the loop in case of limited space, because of the large polyp size or narrow
colon lumen diameter, particularly in the left colon or other flexure locations. Of note,
it should be cautioned that an adequate distance from the ligated loop should be
maintained during cutting to avoid slippage of the loop, which would result in wound
bleeding. In addition, it has been reported that transection can be achieved with a
sufficiently tightened loop if the stalk diameter is <4 mm.16
Another mechanical technique for a safe polypectomy is to place an endoclip on the
pedicle of the polyp to stop blood flow in the stalk. With the endoclip-assisted
technique, some problems of the endoloop-assisted technique can be overcome
because maneuvering the endoclip through the polyp head is not necessary. Luigiano
et al 10 showed the endoclip-assisted technique allowed larger polyps to be resected
than the endoloop-assisted technique with similar complications. However, this can
still be difficult to accomplish when the stalk diameter is far greater than twice the
length of the clip arm (our cases 1 and 4), as 2 clips should ideally be placed in
opposite directions to achieve maximum hemostasis.
Another technique to lower the risk of postpolypectomy hemorrhage using a
diathermic snare is to inject the stalk with an epinephrine solution for reducing blood
flow by vasoconstriction and compression before transaction.17,18 Di Giorgio et al
19 reported similar efficacy by placing an endoloop or by injecting epinephrine, with
a marked reduction in hemorrhage compared with a control group especially when
the diameters of the pedunculated colorectal polyps were between 2 and 3 cm.
However, Paspatis et al 20 suggested that using a combination of epinephrine
injection and an endoloop is more effective than a single epinephrine injection for
large pedunculated colonic polyps (>2 cm).
For our failed case, based on the above concepts, we believe that placing an
endoloop is a more reliable choice for a polyp with a wide stalk, despite the difficulty
involved and the time consumed in maneuvering the endoloop to the stalk because
of the large polyp head with a narrow space. It is important to carefully ensure
sufficient endoloop tightening by observing the color of the polyp head, which
should change to dark red after ligation, and if needed, place another endoloop. In
addition, epinephrine injection into the stalk might be another choice to prevent
postpolypectomy hemorrhage, if one cannot confidently confirm the efficacy of the
former mechanical technique.
In conclusion, based on our experience, combined use of a dual knife and an
adequate prophylactic hemostatic procedure is a novel, feasible, and alternative
technique to conventional endoscopic treatment. It offers en bloc polyp removal in
cases where conventional snare resection is impossible or difficult. A future study
comparing conventional techniques with snare and the technique with Dual Knife is
still required
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