Results
From October 2009 to March 2020, 363 patients met inclusion criteria and
were enrolled in the study. Among them, 241 and 122 women received
surgery in Rouen and Bordeaux respectively. 312 women (86% of the total
sample) were managed by one gynaecological surgeon (H.R.): 223 women in
Rouen (92.5% of patients having surgery in Rouen) and 89 in Bordeaux
(73% of those managed in Bordeaux). The rate of preventive stoma was
71.4% in Rouen (N=172) and 30.3% in Bordeaux (N=37). Rectovaginal
fistula was recorded in 31 cases (8.5%): in 19 women managed in Rouen
(7.9% of women having surgery in Rouen) and in 12 women undergoing
surgery in Bordeaux (9.8% of those managed in Bordeaux).
Table 1 presents patient characteristics, the majority of which were
comparable between the two groups. Patients managed in Bordeaux were
older and had more frequent past history of open abdominal or pelvic
surgery. Table 2 presents intraoperative findings, surgical procedures
and main postoperative complications. Patients managed in Bordeaux had
shorter operative time, larger rectal nodules, deep nodules more often
involving both uterosacral ligaments and rectovaginal space, and more
frequently underwent hysterectomy. Other surgical procedures and
postoperative complications were comparable between the two groups, with
the exception of bladder excision which was more frequent in patients
managed in Rouen.
Table 3 presents the two groups of women stratified on performing or not
performing stoma. The four groups compared were statistically different
regarding rectal nodule size and vaginal infiltration (larger in the
groups receiving stoma in both centres). The height of rectal stapled
line was significantly lower in women undergoing stoma, particularly in
those managed in Bordeaux. Women undergoing nodule excision involving
sacral roots and the sciatic nerve were more likely to have a stoma.
Conversely, the rectovaginal fistula rate was comparable between women
managed in the two centres, with or without stoma. Rectovaginal fistula
was recorded in respectively 9.4%, 10.8%, 10.1% and 7% in women
managed without (8/85) and with stoma (4/37) in Bordeaux and in those
managed without (7/69) and with stoma (12/172) in Rouen.
Table 4 presents the independent relationship between several risk
factors and the likelihood of rectovaginal fistula. Performing rectal
sutures at a height inferior to 8 cm above the anal verge led to a more
than 3-fold increase in risk of rectovaginal fistula, independently of
stoma confection, surgical procedure carried out on the rectum, extent
of vaginal infiltration or associated excision of deep endometriosis
involving pelvic nerves. When compared to women managed in Bordeaux
without fistula, there was a tendency toward a lower probability of
rectovaginal fistula in women receiving stoma in Rouen, however the P
value did not reach statistical significance (P=0.075).
Discussion
Our study compared the risk of rectovaginal fistula in two groups of
patients managed for rectovaginal endometriosis with differing policies
concerning preventive stoma. Despite the stoma rate being more than
halved in one group, no significant difference in risk of rectovaginal
fistula following concomitant excision of rectum and vagina was found.
Our study however showed that a rectal stapled line at a height of
<8 cm was a major risk factor for fistula. This information is
useful for colleagues involved in management of severe forms of
endometriosis.
The major limit of our study relates to the lack of randomisation,
resulting in the presence of women with and without stoma in each group.
In a randomised trial, the assignment of a patient to the arm with or
without stoma is based on a unique randomisation list drawn up by a
statistician, resulting in two similar groups of women to compare. In
our study, as in other non-randomised series7,21,
performing stoma is based on colorectal surgeon decision and
intraoperative events. The particularity of our study relates to
centre-based policies, i.e. an overall intention to carry out a stoma in
patients with concomitant rectal and vaginal repair in Rouen, although
no stoma was ultimately performed in a third of cases, versus an overall
intention to avoid performing a stoma in similar patients in Bordeaux,
where a stoma was performed in one third of the cases. These differing
approaches to the use of stoma led to a comparative study, the results
of which may help in planning a future randomised trial.
The second limit relates to the heterogeneity of techniques used to
remove rectal nodules. Our study is observational and employs data
prospectively recorded in a cohort of patients managed for endometriosis
in two tertiary referral centres. As deep endometriosis is a complex
disease, there is a large variation in length, width, depth and height
of rectal infiltration, requiring an individual surgical approach using
either full thickness disc excision or colorectal
resection22. However, both approaches resulted in the
presence of a rectal stapled line, juxtaposed with vaginal repair. This
condition significantly increases the risk of rectovaginal fistula,
independently of the technique used to remove the nodule.
The third limit relates to the “before and after” design of our study.
Patients were managed in Rouen prior to those in Bordeaux, thus it is
likely that the surgeon practicing in both centres benefited from more
experience during the second time period. This hypothesis is supported
by shorter operative times recorded in Bordeaux.
Our study presents several strengths. The comparability of the two
groups is ensured by the presence of one gyneaecological surgeon in both
centres, who was in charge of management of the majority of patients.
Surgeon recruitment and technique did not vary between the two centres
with colorectal surgeons in Bordeaux and Rouen employing the same
techniques to remove the rectum, i.e. disc excision and segmental
resection, despite their differing approach concerning the use of
preventive stoma. All surgeons involved in this study had extensive
experience in endometriosis, which would logically favour good
postoperative outcomes. Patients were prospectively enrolled in a cohort
and benefited from rigorous follow-up and detailed recording of pre-,
intra- and post-operative data. Data were managed by dedicated research
technicians, avoiding patient lost to follow up and lending support to
the accuracy of the data and the validity of our results.
Our study showed that the prevalence of rectovaginal fistula was
comparable between the four groups stratified on the centre, and use or
not use of stoma. When compared to women managed without stoma in
Bordeaux, the centre with a policy favouring a restrictive use of stoma,
women receiving stoma in Rouen , a centre with large use of stoma, were
found to have a tendency towards a lower rectovaginal fistula rate
(P=0.075), after adjustment for rectal stapled line suture, surgical
procedure on the rectum, size of vaginal infiltration and management of
pelvic nerves (the latter item being an indicator for more complex
surgery). Even though a significant difference might be revealed by a
larger cohort study, expected benefits should be weighed against
disadvantages related to routine stoma use. We previously showed that
women with deep endometriosis benefiting from preventive stoma, had a
8.6% risk of undergoing further surgery to manage specific
stoma-related complications such as bowel occlusions, haemoperitoneum or
leakage of bowel suture at the stoma opening, repair of incisional
hernia or stoma prolapse12. Furthermore temporary
stoma has been shown to increase the risk of colorectal anastomosis
stenosis in women undergoing segmental resection for endometriosis of
the rectosigmoid11. All patients with stoma are
required to undergo additional surgery to close the stoma and restore
the digestive tract, and may engender further stoma-related
disadvantages such as aesthetic harm, residual pain, stoma prolapse,
incisional hernias or subcutaneous infections. The benefits from a
presumed decrease in risk of rectovaginal fistula should be weighed
against the above-mentioned unfavourable consequences.
The occurrence of rectovaginal fistula is a major unfavourable outcome
which impacts patient postoperative well-being. Though the immediate
consequences are not usually life-threatening, as stools are evacuated
through the vagina and not inside the pelvis and abdomen, rectovaginal
fistula repair may be challenging. Simple deviation of stools through a
stoma only incidentally allows rectovaginal fistula repair, as the
presence of vaginal opening in contact with a discontinuous rectal
stapled line may be an obstacle to natural healing1.
Rectovaginal fistula repair requires several additional procedures in
almost half the patients, while stoma closure cannot be carried out
before 10 months on average1. These additional
procedures, such as secondary segmental resection or delayed colo-anal
anastomosis1,2, are much more complex than the repair
of incisional hernia of a stoma scar or endoscopic dilatation of
colorectal anastomosis stenosis. These reasons lend support to a
reduction in risk of rectovaginal fistula by performing preventive
stoma, as has been demonstrated in low rectal resection for rectal
cancer 4-6.
It should be noted that 30.3% of patients managed in Bordeaux
ultimately received a preventive stoma, colorectal surgeons estimating
the risk of rectovaginal fistula to be too high. In Rouen, 28.6% of
patients received no stoma, due to an estimated low risk of rectovaginal
fistula. It results that an average of 40% of patients who had a stoma
in Rouen were unlikely to have had a stoma performed in Bordeaux.
Similarly 40% of those managed without stoma in Bordeaux would have
probably had a stoma performed in Rouen. As patient characteristics and
surgical procedures were comparable between the two centres, any
difference in prevalence of rectovaginal fistula between the two groups
is likely to stem exclusively from comparison between these 40% of
patients, for whom the decision to perform a stoma or not, differed
according to the centre where they were managed. In our series, this
involved 50 patients in Bordeaux and 96 patients in Rouen and though
these patient numbers do not provide sufficient statistical power to
demonstrate a statistically significant difference, our data give an
indication of expected rectovaginal fistula rates in the presence or
absence of stoma. More specifically, the hypothesis of 7% rectovaginal
fistula in women with large indications for stoma appears reasonable,
being similar to that observed in women receiving stoma in Rouen, and to
that reported in another series with a 96% stoma
rate8. A higher rate of rectovaginal fistula in women
with stoma in Bordeaux (10.8%) is also logical, as the risk of fistula
was considered high enough to perform a stoma, by surgeons who would not
routinely perform them. In a future randomised trial, the expected rate
of rectovaginal fistula in women allocated to the arm without stoma,
should be higher than 10.1% (the fistula rate in women in Rouen with no
stoma). A randomisation process would allocate patients with high risk
of rectovaginal fistula to the control group (30.3% of patients who had
a stoma in Bordeaux), logically resulting in fistula rates higher than
those recorded in our series. An important question concerns whether or
not the fistula rate in women without stoma could exceed 16%, thereby
surpassing the cumulative rates of rectovaginal fistula in women with
stoma (7%) and of the surgical procedures required following
complications incurred from routine use of stoma
(8.6%)12. To our knowledge, to date, no other data in
the literature provides answers to this question, highlighting the need
for a randomised trial to compare rectovaginal fistula in women managed
for deep rectovaginal endometriosis with or without stoma.
With regards to whether the rate of fistula in our series is valid and
consistent with that observed in series published by other authors, only
a few studies in the literature have focused on series of women managed
for low rectal endometriosis and concomitant colpectomy, in which risk
of rectovaginal fistula could be comparable to ours. Firstly in a series
of 100 women undergoing low colorectal resection for deep rectovaginal
endometriosis by open route, Dousset et al reported concomitant vaginal
infiltration in 64% of cases, a 96% stoma rate and 6% anastomotic
leakage (8). Secondly in a series of 44 women undergoing low rectal
resection and colpectomy, Belghiti et al recorded a rectovaginal fistula
rate of 15% in women with preventive stoma and 27% in women without
stoma7. On the basis of this, our fistula rate
observed in 363 patients undergoing colpectomy and excision of rectal
endometriosis by either disc excision or segmental resection, appears
reasonable.
In conclusion, this study did not reveal statistically significant
differences in terms of risk of rectovaginal fistula between women with
rectovaginal endometriosis managed respectively by a generalised or
restrictive use of preventive stoma. However, our data underlines the
higher risk of rectovaginal fistula independently related to a low
rectal stapled line, specifically up to 8 cm above the anal verge. Our
results also suggest that a policy of restrictive use of stoma in up to
30% of women with juxtaposed rectal and vaginal sutures does not
significantly increase rectovaginal fistula risk when compared to a much
larger employ of preventive stoma. A further randomised trial would
enable practitioners to better weigh up the benefits in terms of
rectovaginal fistula and related complications versus the risk of
stoma-related complications.
Study funding/competing interest(s): The North-West Inter
Regional Female Cohort for Patients with Endometriosis (CIRENDO) is
financed by the G4 Group (The University Hospitals of Rouen, Lille,
Amiens and Caen) and ROUENDOMETRIOSE Association. No financial support
was received for this study. The authors declare no competing interests
related to this study.
Acknowledgements: The authors are grateful to Amélie Bréant and
Sophie Marinette for the management of data and Helene Braund for her
help in editing the manuscript.