Keywords
low anterior resection - covering ileostomy - anastomotic stricture - anastomotic
leak - rectal cancer
Palavras-chave
ressecção anterior baixa - ileostomia de proteção - estenose anastomótica - vazamento
anastomótico - câncer retal
Introduction
Colorectal cancer is a disease with a major worldwide burden in terms of patient suffering
and cost of treatment. Worldwide, colorectal cancer is the 2nd most common cancer among women, and the 3rd most common among men.[1] Sphincter-preserving low anterior resection (LAR) with total mesorectal excision
(TME) is now considered the standard operation for rectal cancer that allows a primary
anastomosis to be created at a lower level.[2] Anastomotic leakage (AL) rates ranging from 3% to > 20% have been reported, leading
to substantial postoperative morbidity and mortality.[3]
[4] Some authors have recommended the routine use of a temporary stoma to reduce the
morbidity from AL.[5]
[6] In contrast, others have discouraged the routine use of temporary stomas, preferring
selective use. For these authors, a protective stoma is only able to reduce the disastrous
clinical consequences of AL and, instead of what is claimed by other authors, increases
the burden with stoma-related complications.[7]
[8] The overall incidence of clinical leak in colorectal anastomosis is 8%; therefore,
covering stoma confectioning in the majority of patients (92%), if analyzed retrospectively,
has minimal or no clinical usefulness.[9]
Moreover, the complications that can be caused by the stoma itself should not be ignored,
as they include patient discomfort and inconvenience, high output with consequent
dehydration and electrolyte imbalance, and anastomotic complications at the stoma
closure site.[10]
[11]
[12]
[13]
[14]
[15]
[16] Some studies have even reported that reversal of the stoma is associated with complications
in up to 40% of the patients.[17] A recent propensity-matched scoring analysis by Shiomi et al. including about one
thousand patients who underwent one thousand who underwent LAR confirmed that defunctioning
ileostomy does not influence the rate of clinical AL, but does mitigate the consequences
of leakage, reducing the need for urgent reoperation.[18]
Rectal stricture is a chronic pathological narrowing involving a segment of the gut
lumen that leads to difficulty in the passage of gut contents, resulting in clinical
signs and symptoms of complete or partial bowel obstruction.[19] However, prospective studies have defined a stricture anatomically in terms of the
inability to pass a proctoscope (12 mm diameter) or a larger rigid sigmoidoscope (19 mm
diameter) through the AS.[20]
[21] The Cardiff classification[22] graded strictures on a scale of 0 to 2; (0 = no stricture present; 1 = reversible
stricture with limited clinical impact; and 2 = irreversible stricture with severe
clinical impact). Moreover, according to the Cardiff classification, anorectal stricture
was defined as S1, for stenosis with presumed or associated mucosal inflammation,
and S2, by the fibrotic appearance of the stricture.[22]
Rectal strictures may occur de novo after any pathological condition that causes rectal
wall scarring or after colorectal resection anastomosis (the commonest type). Pathologically,
rectal strictures may be benign or malignant. Clinically, rectal strictures may be
asymptomatic or may present as bolus obstruction, constipation, diarrhea, urgency,
or large bowel obstruction.[19] Chronic rectal strictures may give rise to various complications, such as pelvic
and perianal suppurations and fistula formation, stercoral or distention ulcer above
the level of the stricture, chronic blood loss, malignant transformation, and chronic
or acute intestinal obstruction. Anastomotic site ischemia, incomplete doughnuts from
stapled anastomosis, and pelvic infection are some of the risk factors that play a
role in the development of postoperative rectal strictures. However, the role of diverting
stoma in the development of rectal strictures has not been studied extensively.
Objectives
To study and describe the difference in occurrence of ASs in patients submitted to
LAR with covering ileostomy and to LAR without covering ileostomy for rectum carcinoma.
Material and Methods
The present prospective comparative case-control study was carried out from November
2016 to August 2018 in the Division of Colorectal Surgery at a tertiary care hospital
in Kashmir, India. In the present study, rectum carcinoma patients were divided into
two groups: LAR with covering ileostomy (LAR with CI) in one group (study group),
and LAR without covering ileostomy (LAR without CI) in the other group (control group).
The patients were fully evaluated before surgery and were assigned to the study or
control group at the discretion of the operating surgeon. All patients were evaluated
with detailed history and physical examination, and the diagnosis and the stage of
disease were confirmed by Carcino-Embroyonic Antigen (CEA) levels, contrast enhanced
computerized tomography (CECT) of the abdomen/chest/pelvis and, magnetic resonance
imaging (MRI) of the pelvis. The parameters noted in all patients of both groups were
age, gender, body mass index (BMI), occupation, dietary habit, smoking history, associated
comorbidities, American Society of Anesthesiologists (ASA) score, location of the
tumor in relation to the anal verge, Tumor-Node-Metastasis (TNM) stage, execution
of neoadjuvant chemoradiotherapy, level of the anastomosis in relation to the anal
verge, follow-up period, and postoperative digital rectal examination (DRE) findings.
Patients with stage I to IIIC rectal cancer according to the American Joint Committee
on Cancers (AJCC) staging for rectal cancer were included in the present study.[23] Rectum carcinoma patients of all age groups and both genders operated in elective
settings and whose postoperative anastomotic line was within the reach of DRE were
included. However, patients operated in emergency settings presenting with acute bowel
obstruction, perforation and peritonitis, taking immunosuppressant drugs, with stage
IV disease, and severe hypo-albuminemia (serum albumin < 2.5g/dl) were excluded from
the study. Also, the patients requiring restorative colorectal resections for benign
diseases and rectum carcinoma patients with underlying Familial Adenomatous Polyposis
(FAP) requiring Total Proctocolectomy (TPC) with Ileal Pouch Anal Anastomosis (IPAA)
were not included.
Since the definitions, classifications and grading systems of rectal strictures are
ambiguous, and none of them is universally accepted, we used our own institutional
clinical grading classification of rectal strictures based on DRE to describe the
ASs; a readily available tool for every surgeon. We refer to this classification as
the SKIMS Clinical Grading of Rectal Strictures'. SKIMS stands for Sheri-Kashmir Institute
of Medical Sciences, the institute where the present study was undertaken. In the
present study, we have discussed the postoperative anastomotic rectal strictures according
to the SKIMS Clinical Grading of Rectal Strictures ([Table 1]). Postoperatively, we followed the patients of both groups for a maximum period
of 22 months and noted the development of AS. To observe the occurrence and the grade
of ASs, DRE was performed at least twice in every patient by an experienced coloproctologist
at 6 weeks and 12 weeks postoperatively. Thereafter, the DRE was repeated on a need
basis. The DRE findings about AS were noted down according to the SKIMS Clinical Grading
of Rectal Strictures'.
Table 1
SKIMS Clinical Grading of Rectal Strictures
|
Grade of Stricture
|
Severity
|
Description
|
|
I
|
Mild
|
Allowing passage of the index finger on DRE with mild or no resistance and index finger
hugging the rectal stricture circumferentially without causing pain.
|
|
II
|
Moderate
|
Allowing passage of the index finger on DRE but with significant resistance at the
level of the stricture, and patient feeling pain on DRE.
|
|
III
|
Severe
|
Strictures not allowing at all the passage of the index finger on DRE, even under
pressure.
|
Abbreviation: DRE, digital rectal examination.
Statistical Analysis
The data was compiled and statistically analyzed using the chi-squared test, the t-test
and the Fisher exact test, and inferences were drawn from the results of the statistical
analysis. IBM SPSS Statistics for Windows, version 20.0 (IBM Corp., Armonk, NY, USA)
was used for the statistical analysis of the compiled data.
Results
After excluding the patients who did not fulfill the inclusion criteria, the total
number of patients included in the present study was 62. Among these, 29 patients
were included in the study group (LAR with CI), and 33 patients were included in the
control group (LAR without CI). More than 95% of the patients in both groups underwent
LAR for rectal cancer, and total of only 3 (4.5%) patients underwent anterior resection.
In the majority of the patients in both groups, circular staplers were used for anastomosis.
It is also worth mentioning that most of the patients in both groups were operated
by the open approach (83 versus 91%; p = 0.912). The mean postoperative follow-up period was of 9.146 ± 3.50 months (maximum
of 22 months).
The mean age of the patients in the study group was 49.31 ± 15.85 years old, while
in the control group, the mean age was 57.91 ± 1 4.73 years old, and this difference
in the mean age was statistically significant (p = 0.031). The study group had more patients in younger age groups, while the control
group had more patients in elderly age groups. Out of 29 patients in the study group,
17 (58.6%) had received neoadjuvant therapy, while 12 (41.4%) out of 33 patients in
the control group had received neoadjuvant therapy. However, this difference was not
statistically significant (p = 0.080).
The Colon Leakage Score (p = 0.154), the mean distance of the tumor from the anal verge (p = 0.087) and the level of anastomosis after surgery (p = 0.148) in both groups were statistically insignificant ([Table 2]). Similarly, there were no statistically significant differences between the study
and control groups regarding gender distribution (p = 0.191), mean BMI (p = 0.317), preoperative hemoglobin (p = 0.281), serum albumin levels (p = 0.274), comorbidity status (p = 0.316), smoking history (p = 0.624), ASA grade (p = 0.306), and tumor grade and tumor stage (p = 0.665).
Table 2
Parameters Affecting Anastomotic Leakage
|
Patient Group
|
Statistical parameter
|
Colon Leakage Score
|
Distance of tumor from the AV (cm)
|
Level of anastomosis (cm from the AV)
|
|
LAR with CI (
n
= 29)
|
Mean
|
10.65
|
5.34
|
4.00
|
|
SD
|
3.716
|
2.486
|
1.890
|
|
LAR without CI (
n
= 33)
|
Mean
|
9.58
|
7.50
|
5.15
|
|
SD
|
4.50
|
2.398
|
2.093
|
|
p-value
|
|
0.154
|
0.087
|
0.148
|
Abbreviations: AV, anal verge; CI, covering ileostomy; LAR, low anterior resection;
SD, standard deviation.
The anastomotic leak (AL) rate ([Fig. 1]) in the study group was of ∼ 14% (4 out of 29), and in the control group it was
18% (6 out of 33). Thus, the AL rate was higher significantly (p = 0.035) in the control group than in the study group. This difference in the AL rate
between the two groups may be explained by the preventive effect of the covering ileostomy
in decreasing the AL rate.
Fig. 1 Anastomotic leak.
We observed that, during the mean follow-up period of 9.1 months, 8 (28%) patients
in the study group and 2 (6%) patients in the control group developed AS. The p-value
(0.019) was statistically significant regarding the development of AS in both groups
([Table 3], [Fig. 2]). Out of the 8 patients with AS in the study group, strictures in 4 (50%) patients
were of the mild type (Grade I), which allowed the passage of the index finger easily
on DRE. However, in 2 (25%) patients, the strictures were moderate (Grade II) and
allowed the passage of the index finger with significant resistance at the level of
the stricture, while 2 (25%) patients had severe strictures (Grade III) that did not
allow the passage of the index finger on DRE. However, both patients (100%) who developed
strictures in the control group had a mild type (Grade I) of AS.
Table 3
Anastomotic Stricture
|
GROUP
|
Total number of patients
|
Patients developing anastomotic stricture
|
Total percentage of patients Developing stricture
|
|
Grade I
|
Grade II
|
Grade III
|
Total
|
|
LAR with CI
|
29
|
4
|
2
|
2
|
8
|
28%
|
|
LAR without CI
|
33
|
2
|
0
|
0
|
2
|
6%
|
|
p-value
|
0.019
|
Abbreviations: CI, covering ileostomy; LAR, low anterior resection.
Fig. 2 Anastomotic stricture.
Grade I ASs were managed by a high fiber diet and stool bulking agents. Grade II strictures
were managed by regular digital rectal dilatations by the patient himself or by the
attendant (after proper teaching). Severe (Grade III) strictures were put on the clinical
dilatation protocol in the hospital setting by the operating surgeon using Hager metallic
dilators. However, the outcome of this overall treatment protocol for these ASs was
not studied in the present study.
Discussion
Development of AL or of AS is the result of faulty healing at the anastomotic line.
And there is a multitude of diseases and patient-related, surgeon-related and surgical
technique-related factors that influence healing at the site of anastomosis. Most
colorectal surgeons would agree that adherence to good surgical principles is the
best determinant for optimum healing of colorectal anastomoses. In recent years, randomized
control studies that directly compared anastomotic techniques have been largely abandoned,
given the perception that the technique itself (hand sewing, circular versus linear
stapler, one layer versus two layers) is not a sole factor responsible for AL, assuming
that good surgical principles are followed. The one exception to this generalization
has been the stricture rate with staplers. Circular staplers are reported to have
higher stricture rates when compared with linear stapling.[24]
[25] However, even well-perfused, well-constructed anastomoses without any tension along
the anastomotic line can develop an AL or AS. Despite the belief of surgeons in their
own surgical techniques and predictive capabilities, clinical studies demonstrate
that surgeons cannot predict with absolute accuracy which anastomoses will develop
leak or stricture and which will not.[26] The several proposed reasons for the development of AS include ischemia, tension
along the anastomotic line, subacute obstruction, circular staplers, narrow diameter
staplers, and the occurrence of an AL.[27] The pathophysiology for the development of AS is assumed to be a local inflammation
that results in collagen overproduction and in poor bowel wall remodeling.[28] The incidence of colorectal AS varies from 3 to 30%,[29] and is considered to be related to various patient- and treatment-related factors,
including radiation[30] and AL.[31] Most of these anastomotic strictures are simple fibrous constrictions that can be
successfully treated by regular stricture dilation using different techniques. However,
up to 28% of the patients require a surgical correction. This can be technically difficult,
and a permanent colostomy may be needed.[32] In a nutshell, studies reveal that while meticulous attention to the tenets of good
surgical practice are important and should be rigorously adhered to, there still are
some factors that significantly impact anastomotic healing that are not yet fully
understood.[28] One of these understudied factors is the role of diverting stoma in the development
of AS, and in the present study, we tried to elucidate the role of CI in the causation
of ASs.
Since the Colon Leakage Score (CLS) in both groups was comparable and determines the
risk of AL in left-sided restorative colorectal resection. Therefore, the two groups
in our study were theoretically identical regarding the risk of AL. But, practically,
the AL rates ([Fig. 1]) in the study and control groups were of ∼ 14% and 18%, respectively. Thus, the
AL rate was significantly higher (p = 0.035) in the control group than in the study group. This difference in the AL rate
between the two groups may be explained by the preventive effect of the CI in decreasing
the AL, as the CLS does not take into account the role of CI in decreasing the AL.
The total incidence of AS in the study group was of 28%, while in the control group
it was only of 6%. The higher incidence of AS formation in the study group may be
explained by the absence of the regular dilating effect of solid formed stools passing
via the anastomotic site. Kumar et al.,[33] in a retrospective analysis of data from 108 patients with rectal carcinoma who
underwent AR or LAR, reported that 19 (17.6%) patients developed ASa at a median duration
of 8 months (range: 3–20 months). Werre et al. also reported that 8.2% (21 out of
256) patients who underwent LAR developed anastomotic site stricture.[34] Paluvoi et al.[35] also mentioned that patients may have developed AS after low rectal anastomosis
with diverting ileostomy, and suggested that rectal anastomosis should be endoscopically
examined prior to reversing the protective stoma and emphasized the role of transillumination
flexible endoscopy in case the lumen is not properly visualized.
Anastomotic healing complications of postoperative leak and stricture continue to
plague surgeons despite many broadly targeted interventions. The efficacy evaluation
of preventive measures is difficult due to inconsistent definitions and reporting
of these complications. Few interventions have been shown to impact rates of leakage
or stricture. However, new evidence that the intestinal microbiota can play an important
role in the development of anastomotic complications is emerging. The development
of an AS is a result of the complex interactions between genetics, the gut microbiome,
operative technique, antecedent health and comorbidities of the patient, prior patient
exposures, and the subsequent hospital course and exposures ranging from infectious
agents to antibiotics.[27] A more holistic approach to understanding the mechanisms of anastomotic complications
is needed in order to develop tailored interventions to reduce their frequency. Such
an approach may require a more complete definition of the role of the microbiota in
anastomotic healing.
Although one of the prominent identified risk factors for stricture is AL, there are
situations in which ASs form outside of the setting of anastomotic site ischemia,
of the anastomotic tension, and of the AL. These situations and risk factors are unknown.[36] In our study, we also observed that the AL was significantly higher in the control
group but, paradoxically, this group of patients had a significantly lower stricture
rate than the study group. This paradox explains that the AL is not the sole factor
responsible for the development of AS, and this observation suggests that there is
a strong possibility of diversion CI having some role in the formation of ASs. And
the plausible explanation for the increased frequency of AS after LAR with CI seems
to be the lack of movement of solid formed stools across the anastomotic line. This
divests the anastomotic line from the regular dilating effect of solid formed stools
during the early phase of anastomotic healing. Another factor that may have a role
in the causation of AS after LAR with CI is that diverting ileostomy also deprives
the anastomotic site from the normal gut microbiome, which, in turn, may lead to the
alteration of normal anastomotic healing, resulting in stricture formation.
Finally, most endoscopic studies in which the anastomosis can be reached and dilated
have not attempted to classify strictures in a defined way that might advance our
understanding of their pathogenesis and their response to treatment. Therefore, in
order to simplify the grading system of the ASs for the surgeon, we introduced our
SKIMS Clinical Grading of Rectal Strictures. This allows the surgeon to classify the
stricture on an Out Patient Department (OPD) basis by simple DRE, without any need
of bowel preparation and sedation, as is required for endoscopic examinations.
Conclusion
The rate of postoperative AS formation is of 28% in patients of the study group, while
in the control group, only 6% of the patients developed AS. This finding suggests
that CI increases the chances of AS formation after LAR for rectum carcinoma. Also,
the SKIMS Clinical Grading of Rectal Strictures is a simple and handy tool available
for every surgeon to grade, classify, and monitor the postoperative rectal strictures.
