Classification
presented by Burgess NG et al. [1] based on retrospective evaluation, clinical
observations and image analysis.
It allows for
the assessment of deep mural injury (DMI) after endoscopic mucosal resection
(EMR) of laterally spreading colorectal lesions with the diameter > 20mm. The
most important is accurate, endoscopic post-resection assessment using advanced
imaging techniques, which determines further proceeding.
During EMR
procedure, extremely important is to properly elevate and stain the lesion
appropriate solutions with dyes. Injection separates the lesion from muscular
layer, reducing thermal injury, risk of perforation and bleeding. Additionally,
facilitates en-bloc resection in the technical aspect [2].
In turn,
addition of staining agents to the injection solution, allows identifying the
area of submucosal injection and distinguishing between the muscle layer and
the submucosa. Morover, identification of the lateral and deep margins of the
target lesion is more detailed during te whole procedure (before and after
resection). Also, the staining dye may facilitate evaluation of residual lesion
at the end of endoscopic resection and improve recognition of muscularis
propria injury as an intraprocedural perforation [2].
Therefore,
the authors used: 1 ml of 0.4% indigo carmine or methylene blue and 1 ml of 1:
10,000 adrenaline in combination with 8 ml of saline solution [1].
In this
classification a proper injection is important because it allows for an
accurate assessment of colon wall layers and further proceeding (clip vs. not
clip vs. consult with the surgeon).
The
classification is V gradual and concerns the correct view in the site
after EMR where mucosa was removed correctly, up to clean / contaminated
perforation [1].
The
terms included in the classification:
Target
sign
– a symptom of endoscopic resection of muscularis propria and sites of
potential perforation (circularly arranged white fibers with a dark spot in the
center).
Specimen
sign
– seen in the removed lesion, in the place of the cut seen from the bottom.
Whale sign – a circular wrap of white fibers of muscularis propria without injury (compared to the abdomen of a part of the blue whale)
Sydney classification adapted from Ref 1.
Type 0
-mucosal
defect after correct resection, blue mat color with visible oblique
intersecting fibers of the submucosa
– submucosal vessels may be visible, but they are not damaged
Type I
– removed
submucosal layer
– white, circular muscularis propria fibers visible without damage – whale sign
Type II
– no
distinction between the submucosa and muscularis propria, focal loss of the
submucosal plane rising concer for mucularis propria injury
-damage of muscularis propria difficult to visualize
Type III
-damage of muscularis propria (1) visible as a target sign (2) in the resection site or specimen sign (3) visible in the removed lesion, „from the bottom“ at the cut site
Type IV
-clearly
visible perforation (whole with a white cautery ring) without stool residue
contamination
– perforation
should be closed immediately, however, if possible, complete resection before
placing the clip
– if the
lesion is not completely removed before clipping, further resection attempts
may be hindered by submucosal fibrosis due to the clip
Type V
-perforation
contaminated with stools
– hole should
be closed and surgically consulted
– surgical intervention is required adequate to the clinical condition, in case of peritonitis, peritoneal fluid, or unsuccessful endoscopic resection
Conclusions
from the study [1]:
Potential DMI (type
I and II) is associated with increasing lesion size, SMF and transverse colon
location.
DMI type III–V:
(target signs and perforations) are associated with en bloc resection,
transverse colon location and HGD or SMIC.
Type I injuries do
not require clip placement
DMI type III–V
require closure of the injured MP
All type II
injuries should also ideally be clipped
The majority of patients with target signs
(type III DMI) can be managed with same day discharge if they are well and the
injury is securely closed.
Intraprocedural
perforation occurs in 0.5% and clinically significant perforation occurs in
0.2%.
Potentially serious DMI syndromes are not infrequent,
but if recognised they may be managed safely and effectivelywithout
serious clinical sequelae, in many cases on an outpatient basis.
type III – V DMI (target sign
or perforation) occurs in 3.0% and mainly affects lesions located in the transverse
colon, en bloc resection, HGD and invasive cancer,
lesions ≥25 mm removed entirely
are particularly associated with a high DMI risk, therefore risk
and the advantages
of en bloc resection before EMR should be assessed.
Figures adapted from Ref. 1.
References
Burgess NG, et al. Deep mural
injury and perforation after colonic endoscopic mucosal resection: a new
classification and analysis of risk factors. Gut 2016; 0:1–11.
Castro R, Libânio D, Pita I, Dinis-Ribeiro M.
Solutions for submucosal injection: What to choose and how to do it. World J Gastroenterol.
2019; 25: 777–788.
Author: Pawlak K. (1) Hospital of the Ministry of Interior and Administration, Department of Internal Medicine, Cardiology, Gastroenterology and Endocrinology, Szczecin, Poland
Beitrag von:
Katarzyna Pawlak, Hospital of the Ministry of Interior and Administration, Department of Internal Medicine, Cardiology, Gastroenterology and Endocrinology, Szczecin, Poland
Hospital of the Ministry of Interior and Administration, Department of Internal Medicine, Cardiology, Gastroenterology and Endocrinology, Szczecin, Poland