When is Primary Anastomosis Safe in the Colon?
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Introduction
History - Development of the Paradigm
Revision of the Paradigm - Colonic Injuries
Revision of the Paradigm - The Morbidity of Colostomy
Revision of the Paradigm - Diverticulitis, Obstruction
and Sigmoid Volvulus
Do Stapled or Hand-Sewn Techniques Influence Results?
Revision of the Paradigm - The Need for Mechanical Bowel Preparation
(MBP)
Conclusions
References
Clinical Scenarios
Introduction
The repair by suture or resection of diseased or injured colon is one of the
most important skills in general surgery. Untreated or treated improperly these
conditions cause significant morbidity in terms of intra-abdominal infection,
fistulae, or death from generalized peritonitis. Today in Western medicine the
two most common conditions requiring emergency colonic resection are obstructing
colon cancers and complicated diverticulitis. In Africa, the equivalent conditions
are gangrenous sigmoid volvulus and penetrating injuries resulting in colonic
perforation. The deleterious consequences of primary anastomosis of the obstructed
left colon with a tenuous blood supply, filled with pathogenic organisms and/or
of the perforated colon with various degrees of peritoneal contamination fostered
a surgical paradigm which precluded primary anastomosis of the left colon unless
preoperative mechanical bowel preparation and antibiotic prophylaxis had been
undertaken.
This was certainly the paradigm I was taught and which I practised throughout
1980-2000 in Canada. As Primary Surgery, Non-Trauma, an exemplary
text for International surgeons from which I plan to quote extensively in these
Reviews, states: “You cannot safely anastomose large gut to large
gut when it is obstructed and instead you have to let its contents escape through
an ostomy. When large gut is to be anastomosed, it has to be carefully prepared
first with enemas and antibiotics…”King, 1990
(1) A similar attitude held for colonic injuries.
The definitive International Committee of the Red Cross 1990 edition of
Surgery for Victims of War states: “The general rule
is that a damaged colon should be exteriorized or defunctioned by proximal colostomy”.
Dufour, 1990 (2)
Over the last decade the tenets underlying this paradigm have been seriously
questioned and the whole approach to emergency colonic surgery has been revised.
This Review will briefly consider the historical development of the paradigm
and then detail its decline through experience with colon injuries, the morbidity
of colostomies themselves, alternatives in acute colonic disease such as obstruction,
diverticulitis and sigmoid volvulus and finally the fundamental questioning
of the value of mechanical bowel preparation.
History - Development of the Paradigm
The history of the development of treatments for perforated, gangrenous or obstructed
colons reflects the fear surgeons had for the dangers of anastomotic dehiscence.
The late 19th century saw the development of standardized techniques for “two-layer”
bowel anastomosis Ellis, 1989 (3) and at
the same time non-anastomotic techniques for the acutely diseased colon - the
colostomy. The Paul-Mikulicz operation exteriorized the diseased colon as a
double-barreled colostomy. Mayo in 1907 recommended temporary transverse colostomy
for obstructing diverticulitis. In the 20th century treatment for perforated
diverticulitis evolved towards the Hartmann procedure, proposed for colon cancer
by Henri Hartmann in 1921, with resection of the perforated segment and proximal
colostomy. This procedure showed an improvement in mortality over proximal colostomy,
suture and drainage. Parks, 1989 (4)
For obstructing left-sided carcinomas a traditional three-staged process was
initially proposed which included initial transverse colostomy, followed by
resection-anastomosis and finally closure of the colostomy. Because of the recognized
delay and difficulties of three operations, alternatives such as sub-total colectomy
as well as techniques for on-table bowel cleansing and intra-colonic stents
were developed. Lesions of the right and transverse colon could be managed by
forms of right hemicolectomy and ileo-colic anastomosis. But the taboo of anastomosing
unprepared left colon without proximal diverting colostomy persisted.
Ogilvie’s WWII experience established exteriorization of the damaged bowel
and fecal diversion as the primary modalities of therapy for wartime colon injuries.
Mortality dropped from 50% to 10% and this approach was initially applied to
civilian penetrating colonic injury. The treatment for extra-peritoneal rectal
injuries included colostomy, irrigation of the rectal stump and wide perineal
drainage.
While some form of fecal diversion was considered mandatory for emergency left-sided
colon lesions, an elaborate preparation was undertaken for elective colon surgery.
Mechanical bowel preparations (MBP) to remove the fecal contents were developed.
These progressed from prolonged fasting, fluids only and cathartics to rapid
polyethylene glycol solution and sodium phosphate administration. At the same
time multiple different regimes of peri-operative antibiotics have been found
to be useful in reducing post-operative septic complications and mortality Song,
1998 (5). The antibiotics need to be active against
enteric aerobic and anaerobic organisms and should be limited to the operative
period. A single dose is adequate for operations less than 2 hours in duration.
Gentamycin and metronidazole are a good combination. Parenteral and oral antibiotics
may have a cumulative effect. Lewis, 2002 (6)
Of all the traditional recommendations concerning colon surgery only those relating
to peri-operative antibiotics have withstood scientific scrutiny and are uniformly
practised.
While much of surgical practise is a learned behaviour arising from the apprenticeship
system of surgical education, the second half of the 20th century has seen the
rise of evidence-based medicine and the prospective, randomized clinical trial
(RCT). These types of studies have begun to alter surgical practise.
Revision of the paradigm – colonic
injuries
It was in the field of colon trauma that exceptions to the rule prohibiting
primary colon repair initially began to be advocated. Beginning first with right-sided
injuries, subsequently extending to left sided lesions, those that could be
repaired without resection, then to resection with proximal colostomy and finally
the most recent recommendations accepting resection and primary anastomosis
without fecal diversion as appropriate surgery. The initial caveats to this
most radical treatment included limited time from injury to repair, minimal
contamination, few associated injuries. Whereas Cornwell, 1998
(7) questioned the use of primary repair
for high risk penetrating trauma patients, by 2001, the same group, Demetriades,
2001 (8), having undertaken a multi-center
prospective study, concluded that all colon injuries could be managed without
fecal diversion without influencing morbidity or mortality. Gonzalez,
1996 (9) drew similar conclusions. However, Miller,
2002 (10) still raised a cautionary note for high
risk patients, those with high trauma scores, destructive colon injuries, need
for multiple blood transfusions, etc. In a meta-analysis, (which pools results
from multiple RCTs), Singer, 2002 (11) clearly
favoured primary repair without diversion for all risk categories. Kamwendo,
2002 (12) from South Africa showed that increasing
time after injury did not preclude primary repair. Esraghi, 1998
(13) reflected the changing opinions of American surgeons
on this question. Demetriades, 2004 (14)
sums up current thinking. Note should be made that the need remains for colostomy
in rectal injuries, because of the particular anatomy of this problem. These
changes are reflected in the 1998 edition of Surgery for Victims of
War which tentatively states that fecal diversion for colonic injuries
“has been the rule in war surgery, but the ICRC’s working experience
has shown that it is seldom necessary.” (15)
Revision of the paradigm – the morbidity
of colostomy
While colostomy itself in the proper setting may be a valuable procedure, the
need for and risks of additional surgical procedures increase the morbidity
to the patient. Khoury, 1996 (16) reviewed
the results of colostomy closure in 46 patients with a complication rate of
24%. Riesener, 1997 (17) reviewed 548 closures
since 1972. He advocated MBP and peri-operative antibiotics. However their best
complication rate was still 27%. In Mealy, 1996 (18)
only 50% of patients had their stomas closed. Berne, 1998 (19)
reviewed colostomy closures after trauma and also found high morbidities, although
this was not the case after rectal injury. Chandramouli, 2004
(20) reviewed the experience of colostomies and their closure
in children.
Revision of the paradigm – diverticulitis,
obstruction and sigmoid volvulus
With the recognition of the increased morbidity of subsequent surgical procedures
have come alternatives such as on-table lavage Sitzler, 1998 (21)
and intra-colonic stenting. However, in the 1990s more surgeons began to perform
resection and primary anastomosis in acute non-traumatic colon conditions. Trillo,
1998 (22) reported 43 cases without mortality. Goozen,
2001 (23) reported 45 patients with acute obstructive
or perforated diverticulitis treated with resection and primary anastomosis.
There were three deaths from anastomotic leaks-all in obstructed patients. They
cautioned its use in these cases. Salem, 2004 (24)
reviewed 98 published studies since 1957 and called for a RCT comparing
resection and colostomy with primary anastomosis in acute surgical diverticulitis.
Whetstone, 2004 (25) giving guidelines for
management of diverticulitis insisted that the Hartmann procedure is the appropriate
operation when emergency surgery is indicated.
Various forms of right-hemicolectomy and ileo-colic anastomosis have been accepted
for some time as the surgical procedure of choice in acute right-sided obstructions.
For left-sided obstructions some authors advocate subtotal colectomy and ileo-colic
anastomosis. Remst, 1998 (26) is an example.
Edino, 2005 (27) carried out on table lavage in 32
consecutive patients without mortality. Harris, 2001 (28)
reviewed the use of endoluminal stents obviating the need for emergency surgery.
DeSalvo, 2004 (29) carried out a literature
review and concluded that there existed inadequate studies comparing primary
anastomosis and colostomy in left-sided obstructions and recommended further
RCTs. Clearly no definitive conclusion can be drawn concerning the safety of
primary anastomosis without colostomy for acute left-sided obstructions.
The non-Western experience with sigmoid volvulus also favours divergence from
the paradigm. Kuzu, 2002 (30) reported 102
patients with sigmoid volvulus requiring emergency surgery. Although the operative
procedure was chosen by the surgeon about half the patients had resection and
primary anastomosis and their infectious complications and death rates were
similar to those with the Hartmann procedure. De, 2003 (31)
reported 197 patients who all had resection and primary anastomosis without
preoperative or intra-operative bowel preparation. There were only 2 leaks and
2 deaths, a remarkable result. Raveenthiran, 2004 (32)
reported 57 patients half of whom had gangrenous colons with similar results.
Despite the lack of clinical trials, surgeons in developing countries are using
resection and primary anastomosis in sigmoid volvulus requiring acute surgical
intervention..
Do stapled or hand-sewn techniques influence
results?
Demetriades, 2002 (33) published a prospective,
but uncontrolled, study in colonic injuries comparing stapled and sutured repairs
and found no difference in terms of anastomotic leak or morbidity. Lustosa,
2001 (34) performed a meta-analysis of 9 RCTs and
concluded that the two surgical techniques were indistinguishable in terms of
results. These results are very significant for the African experience where
hand-sewn techniques predominate.
Revision of the paradigm – the need for mechanical
bowel preparation (MBP)
While the value of peri-operative antibiotics has stood the test of scientific
scrutiny, the other “sacred cow” of elective colon surgery, the
mechanical bowel prep, has not. Hughes in 1972 was the first to conduct a RCT
of patients undergoing primary anastomosis after elective left-sided colon resection
with and without MBP. No differences in terms of anastomotic leaks and morbidity
were found. Geldere, 2001 (35) reported 250
patients undergoing elective and emergency right and left colon resections and
anastomoses without MBP. This series had an anastomotic failure rate of only
1.25%. Zmora, 2003 (36) and Ram,
2005 (37) each published RCTs comparing elective
resection and anastomosis with and without MBP and could find no difference
in leakage rates or morbidity. Finally, Bucher, 2004 (38)
did a meta-analysis of 7 RCTs and found that MBP might actually be harmful.
Patients undergoing MBP had a higher rate of septic complications than those
with unprepared bowels. These reports show the capability of scientific studies
to throw doubt on traditional surgical practise.
Conclusions
What kinds of recommendations can be made for African surgeons undertaking colon
surgery in 2005?
1. Any recommendation must be dependent on the surgeon’s experience,
the local conditions,
anaesthetic facilities, etc.
2. Almost all colonic injuries can be repaired without fecal diversion. The
sole exception would be for
severe injuries requiring major resection, where the patient requires multiple
blood transfusions, is in
shock or has massive contamination.
3. Sigmoid resection and primary anastomosis without bowel preparation may be
advised as the emergency operation for gangrenous or irreducible sigmoid volvulus.
4. The results of surgical repair are the same for stapled or sutured techniques.
5. In acute surgical left-colon diverticulitis and obstruction, the evidence
is not yet conclusive as to the role of anastomosis without fecal diversion.
Hartmann procedure may be the safer route, but this is not proven. On-table
colonic lavage is an option instead of colostomy.
6. Colostomy closure is not a benign procedure.
7. Antibiotics with activity against aerobic and anaerobic bacteria need to
be given parenterally in the peri-operative period alone. Their post-operative
use should be restricted to cases with established infection. Pre-operative
oral antibiotics may have an added value.
8. In elective colon operations there appears to be no value to mechanical bowel
preparation. Even as I write this my surgical prejudices rebel against such
a notion.
Brian Ostrow MD, FRCS(C)
Guelph, Ontario
Canada
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