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272
R.P. Kiran and V.W. Fazio
creation to the operative diffi culties of reoperative abdominal
and pelvic surgery required for pouch mobilization. Patients
who undergo the procedure are however extremely satisfi ed
with the operation [ 24 ].
Pouch Failure: Permanent Diversion with Pouch In Situ or Pouch Excision?
Key Concept : Pouch excision , rather than diversion , is the
preferred option for patients who develop pouch failure and
are not candidates for restoration of intestinal continuity .
When problems with the ileoanal pouch necessitate the
consideration of an ostomy, options include pouch excision
with a permanent end ileostomy or instead an ostomy (loop
or end) above a pouch, leaving the pouch in situ. Leaving
the pouch in situ avoids the diffi culties and hence the complications associated with reoperative pelvic surgery.
However, whether the pouch itself (if left in place) leads to
troublesome symptoms or is at risk for malignant change is
a concern. We evaluated the relative risks and benefi ts of
the two approaches [ 25 ]. Perioperative outcomes and qual-
ity of life (QOL) using pouch and SF-12 questionnaires
were evaluated for 136 patients with pouch failure who
underwent either a loop ileostomy above a pouch in situ or
pouch excision. Thirty-day postoperative complications
were similar between the groups. While long-term urinary
and sexual functions after a median of 9.9 years were similar for the two groups, quality of life and health, current
energy level, Cleveland Global QOL score, and SF-12
mental and physical component scales were signifi cantly
higher after pouch excision. Anal pain and seepage with
pad use were predominant complaints of the group that
underwent loop ileostomy alone. Long-term data on pouch
and anal transitional zone surveillance were available for
18 patients who had the pouch in situ and did not reveal any
evidence of dysplasia or cancer. However, the indication
for surgery in eight of the patients who underwent pouch
excision was dysplasia or cancer of the anal transitional
zone or pouch. These results suggest that although technically more challenging, pouch excision, rather than ileostomy creation, is the preferable option for patients who
develop pouch failure and are not candidates for restoration
of intestinal continuity. Since ostomy creation was not
associated with neoplasia in the pouch left in situ, this
option may be a reasonable intermediate- or long-term
alternative when pouch excision is not feasible or advisable
and when concerns about reoperation in the pelvis are signifi cant. An ostomy creation in other circumstances also
offers some patients the anticipation of eventual correction
of the pouch-related complication and reestablishment of
intestinal continuity. Pouch surveillance, however, bears
consideration when the pouch is left in situ.
Cancer of the Pouch
Key Concept : This rare condition may occur with both stapled
and hand - sewn IPAA and warrants appropriate surveillance .
This is rare and may be located in the pouch or anal transitional zone. Mucosectomy with a hand-sewn anastomosis does
not eliminate the risk of cancer. A stapled IPAA may facilitate
surveillance of the pouch and anal transitional zone, but patients
are at risk for cancer after both types of anastomoses.
Redo Pouch Surgery
Key Concept : Patients with pouch failure secondary to a
wide variety of conditions including septic complications
related to IPAA including anastomotic leak , pelvic abscess
and fi stula , strictures , and pouch dysfunction due to other
causes are suitable candidates for pouch excision .
Repeat abdominal surgery with abdominoperineal reconstruction or revision of the ileal pouch with or without the
creation of a neoileal pouch-anal anastomosis is a reasonable
option for selected patients with a failed pouch [ 26 – 32 ].
A recent review of our experience with the procedure suggests
that the procedure is associated with acceptable pouch salvage, functional outcomes, and quality of life [ 33 ]. For 241
patients who underwent the procedure between 1983 and
2007, functional and quality of life outcomes were encouraging. When matched to patients who underwent primary IPAA,
redo pouch patients reported greater daytime and night seepage and daytime pad usage after a median follow- up of 5 years,
but other functional outcomes and quality of life were similar.
Of the 241 patients, 170 cases had the original pouch salvaged
while a new pouch was constructed in the remaining.
Operative Technique
With the patient in the Lloyd-Davies position, the abdomen
and perineum are prepped and draped. We prefer the routine placement of bilateral ureteral stents in order to minimize injury and identify any damage to these structures
during surgery. The abdomen is entered through the previous incision, and after the lysis of any adhesions encountered, the pouch is mobilized to the pelvic fl oor. The pouch
is disconnected from the anastomosis, delivered into the
abdomen, and evaluated. The state and residual capacity of
the pouch, the length of remaining small intestine, and
anticipated challenges with reach of the pouch to the anal
canal determine whether the old pouch is revised or instead
excised with a new pouch created prior to reanastomosis. If
the redo IPAA is performed for pouch failure secondary to
a chronic presacral abscess cavity (Fig.
tus within the cavity is excised or drained (Fig.
17.10a ), the detri-
17.10b ).
17 Ileal Pouch Complications
273
a
b
c
Fig. 17.10 ( a ) Chronic presacral abscess complicating a pelvic pouch
(Reprinted with permission, Cleveland Clinic Center for Medical Art &
Photography © 2012. All Rights Reserved). ( b ) Debridement of the
presacral abscess cavity after disconnection of the pouch from the
anastomosis (Reprinted with permission, Cleveland Clinic Center for
Medical Art & Photography © 2012. All Rights Reserved). ( c ) Hand-sewn
redo pouch- anal anastomosis (Reprinted with permission, Cleveland Clinic
Center for Medical Art & Photography © 2012. All Rights Reserved)
274
R.P. Kiran and V.W. Fazio
A repeat ileal pouch-anal anastomosis is usually made after
mucosectomy at the level of the dentate line by a handsewn anastomosis (Fig.
17.10c ). In rare cases a stapled
anastomosis is chosen. A diverting loop ileostomy is usually created or the existing ileostomy left in place above the
redo IPAA.
Summary Pearls
1. Preoperative decision-making for patients undergoing
restorative proctocolectomy: Staging the procedure
reduces perioperative complications at IPAA. A threestage procedure should be considered in patients with
severe colitis, poor nutrition, and immunosuppression.
2. Identifying factors associated with perioperative septic
complications and efforts directed at the reduction of
these complications improve pouch function and
retention.
3. The prompt identifi cation and appropriate management
of early perioperative complications after IPAA, when
they do occur, likely improves outcomes.
4. Pouch salvage is feasible in a signifi cant proportion of
patients with early and late pouch-related complications
and pouch failure.
5. Management of pouch failure should be individualized,
depending upon patient preference and a thorough determination of the pros and cons of the various surgical
options. The perioperative surgical risk, potential for
complications, and anticipated eventual functional outcomes and quality of life for each procedure need to be
carefully considered and discussed before embarking on
surgery for pouch failure.
References
1. Fazio VW, Tekkis PP, Remzi F, Lavery IC, Manilich E, Connor J,
et al. Quantifi cation of risk for pouch failure after ileal pouch anal
anastomosis surgery. Ann Surg. 2003;238(4):605–14; discussion
614–7.
2. Manilich E, Remzi FH, Fazio VW, Church JM, Kiran RP. Prognostic
modeling of preoperative risk factors of pouch failure. Dis Colon
Rectum. 2012;55(4):393–9.
3. Breen EM, Schoetz Jr DJ, Marcello PW, Roberts PL, Coller JA,
Murray JJ, et al. Functional results after perineal complications of
ileal pouch-anal anastomosis. Dis Colon Rectum. 1998;41:691–5.
4. Selvaggi F, Sciaudone G, Limongelli P, Di Stazio C, Guadagni I,
Pellino G, et al. The effect of pelvic septic complications on function and quality of life after ileal pouch-anal anastomosis: a single
center experience. Am Surg. 2010;76:428–35.
5. Hallberg H, Ståhlberg D, Akerlund JE. Ileal pouch-anal anastomosis
(IPAA): functional outcome after postoperative pelvic sepsis. A prospective study of 100 patients. Int J Colorectal Dis. 2005;20:529–33.
6. Chessin DB, Gorfi ne SR, Bub DS, Royston A, Wong D, Bauer JJ.
Septic complications after restorative proctocolectomy do not
impair functional outcome: long-term follow-up from a specialty
center. Dis Colon Rectum. 2008;51:1312–7.
7. Kiely JM, Fazio VW, Remzi FH, Shen B, Kiran RP. Pelvic sepsis
after IPAA adversely affects function of the pouch and quality of
life. Dis Colon Rectum. 2012;55(4):387–92.
8. Kiran RP, da Luz Moreira A, Remzi FH, Church JM, Lavery I,
Hammel J, et al. Factors associated with septic complications after
restorative proctocolectomy. Ann Surg. 2010;251(3):436–40.
9. Kirat HT, Remzi FH, Shen B, Kiran RP. Pelvic abscess associated
with anastomotic leak in patients with ileal pouch-anal anastomosis
(IPAA): transanastomotic or CT-guided drainage? Int J Colorectal
Dis. 2011;26(11):1469–74.
10. Lian L, Serclova Z, Fazio VW, Kiran RP, Remzi F, Shen B. Clinical
features and management of postoperative pouch bleeding after
ileal pouch-anal anastomosis (IPAA). J Gastrointest Surg.
2008;12(11):1991–4.
11. Lee PY, Fazio VW, Church JM, Hull TL, Eu KW, Lavery IC.
Vaginal fi stula following restorative proctocolectomy. Dis Colon
Rectum. 1997;40(7):752–9.
12. Shah NS, Remzi F, Massmann A, Baixauli J, Fazio VW.
Management and treatment outcome of pouch-vaginal fi stulas
following restorative proctocolectomy. Dis Colon Rectum.
2003;46:911–7.
13. Heriot AG, Tekkis PP, Smith JJ, Bona R, Cohen RG, Nicholls RJ.
Management and outcome of pouch-vaginal fi stulas following
restorative proctocolectomy. Dis Colon Rectum. 2005;48(3):451–8.
14. Johnson PM, O’Connor BI, Cohen Z, McLeod RS. Pouch-vaginal
fi stula after ileal pouch-anal anastomosis: treatment and outcomes.
Dis Colon Rectum. 2005;48(6):1249–53.
15. Gajsek U, McArthur DR, Sagar PM. Long-term effi cacy of the button
fi stula plug in the treatment of Ileal pouch-vaginal and Crohn’s- related
rectovaginal fi stulas. Dis Colon Rectum. 2011;54(8):999–1002.
16. Loungnarath R, Dietz DW, Mutch MG, Birnbaum EH, Kodner IJ,
Fleshman JW. Fibrin glue treatment of complex anal fi stulas has
low success rate. Dis Colon Rectum. 2004;47(4):432–6.
17. Wexner SD, Ruiz DE, Genua J, Nogueras JJ, Weiss EG, Zmora O.
Gracilis muscle interposition for the treatment of rectourethral, rectovaginal, and pouch-vaginal fi stulas: results in 53 patients. Ann
Surg. 2008;248(1):39–43.
18. Akbari RP, Madoff RD, Parker SC, Hagerman G, Minami S,
Bullard Dunn KM, et al. Anastomotic sinuses after ileoanal pouch
construction: incidence, management, and outcome. Dis Colon
Rectum. 2009;52:452–5.
19. Nyam DC, Wolff BG, Dozois RR, Pemberton JH, Mathison SM.
Does the presence of a pre-ileostomy closure asymptomatic pouchanastomotic sinus tract affect the success of ileal pouch-anal anastomosis? J Gastrointest Surg. 1997;1:274–7.
20. Swain BT, Ellis CN. Fibrin glue treatment of low rectal and pouchanal anastomotic sinuses. Dis Colon Rectum. 2004;47:253–5.
21. Ahmed Ali U, Shen B, Remzi FH, Kiran RP. The management of
anastomotic pouch sinus after IPAA. Dis Colon Rectum. 2012;
55(5):541–8.
22. Ehsan M, Isler JT, Kimmins MH, Billingham RP. Prevalence and
management of prolapse of the ileoanal pouch. Dis Colon Rectum.
2004;47(6):885–8.
23. Kirat HT, Kiran RP, Oncel M, Shen B, Fazio VW, Remzi FH.
Management of leak from the tip of the “J” in ileal pouch-anal anastomosis. Dis Colon Rectum. 2011;54(4):454–9.
24. Lian L, Fazio VW, Remzi FH, Shen B, Dietz D, Kiran RP. Outcomes
for patients undergoing continent ileostomy after a failed ileal
pouch-anal anastomosis. Dis Colon Rectum. 2009;52(8):1409–14;
discussion 4414–6.
25. Kiran RP, Kirat HT, Rottoli M, Xhaja X, Remzi FH, Fazio VW.
Permanent ostomy after ileoanal pouch failure: pouch in situ or
pouch excision? Dis Colon Rectum. 2012;55(1):4–9.
17 Ileal Pouch Complications
275
26. Ogunbiyi OA, Korsgen S, Keighley MR. Pouch salvage. Long- term
outcome. Dis Colon Rectum. 1997;40:548–52.
27. Dehni N, Remacle G, Dozois RR, Banchini F, Tiret E, Parc R.
Salvage reoperation for complications after ileal pouch-anal anastomosis. Br J Surg. 2005;92:748–53.
28. MacLean AR, O’Connor B, Parkes R, Cohen Z, McLeod RS.
Reconstructive surgery for failed ileal pouch-anal anastomosis:
a viable surgical option with acceptable results. Dis Colon Rectum.
2002;45:880–6.
29. Baixauli J, Delaney CP, Wu JS, Remzi FH, Lavery IC, Fazio VW.
Functional outcome and quality of life after repeat ileal pouch-anal
anastomosis for complications of ileoanal surgery. Dis Colon
Rectum. 2004;47:2–11.
30. Sagar PM, Dozois RR, Wolff BG, Kelly KA. Disconnection, pouch
revision and reconnection of the ileal pouch-anal anastomosis. Br J
Surg. 1996;83:1401–5.
31. Tekkis PP, Heriot AG, Smith JJ, Das P, Canero A, Nicholls RJ.
Long-term results of abdominal salvage surgery following restorative proctocolectomy. Br J Surg. 2006;93:231–7.
32. Fazio VW, Wu JS, Lavery IC. Repeat ileal pouch-anal anastomosis
to salvage septic complications of pelvic pouches: clinical outcome
and quality of life assessment. Ann Surg. 1998;228:588–97.
33. Remzi FH, Fazio VW, Kirat HT, Wu JS, Lavery IC, Kiran RP.
Repeat pouch surgery by the abdominal approach safely salvages
failed ileal pelvic pouch. Dis Colon Rectum. 2009;52(2):
198–204.
The Failed Anastomosis
Nathan Smallwood , Matthew G. Mutch ,
and James W. Fleshman
Key Points
• Be aware of the propensity for poor perfusion at the
splenic fl exure, especially during high ligation, and
the posterior rectal stump following TME.
• Preventive measures for anastomotic leaks are more
likely to be identifi ed preoperative for a right
colectomy and intraoperative for left.
• Simplify your decision on whether to perform
proximal diversion by answering three questions.
What is the risk based upon location? Can the
patient tolerate a leak? What are the patient wishes?
• With a leaking anastomosis, proximal diversion
many times is just as effective as resection and end
ostomy, but with less associated morbidity and risk
of permanent stoma.
• Even in the diverted patient, inadequate treatment
of a leak can lead to chronic pelvic sepsis causing
increased morbidity and poor long-term anorectal
function.
• Most leaks can be managed with a minimally
invasive approach and an ostomy avoided.
1 8
The Healing Anastomosis
As we explore the causes of anastomotic failure and ways to
prevent and manage the failure, it is important to have a thorough understanding of the normal healing process. With this
fundamental knowledge, we can better understand how our
operations positively and negatively alter the natural process
of anastomotic healing.
The Anatomical Perspective
Key Concept : One of the fundamental principles of a healthy
anastomosis is understanding bowel wall anatomy , and
while the submucosa provides “ strength ,” each layer impacts
outcomes for both stapled and hand - sewn anastomoses .
There are specifi c characteristics of each layer of the intestinal wall that have a profound infl uence on an anastomosis.
In 1887, Halsted revealed that the submucosa provided the
strength for a sutured anastomosis. This concept, though simple today, was revolutionary and had a dramatic impact on the
success of intestinal anastomoses. In fact, anastomotic failures were so common in 1887 that the advisability of performing a bowel anastomosis was in question [ 1 ].
Mucosa
N. Smallwood , MD
Department of Surgery , Baylor University Medical Center ,
3500 Gaston Ave. , Dallas , TX 75246 , USA
e-mail: cottonsmallwood@yahoo.com
M. G. Mutch , MD
Department of Surgery, Section of Colon and Rectal Surgery ,
Washington University School of Medicine ,
660 South Euclid Ave Campus , 8109 , St. Louis , MO , USA
e-mail: mutchm@wustl.edu
J. W. Fleshman , MD (
Department of Surgery , Baylor University Medical Center ,
3500 Gaston Ave. , Dallas , TX 75246 , USA
e-mail: james.fl eshman@baylorhealth.edu
S.R. Steele et al. (eds.), Complexities in Colorectal Surgery,
DOI 10.1007/978-1-4614-9022-7_18, © Springer Science+Business Media New York 2014
*)
The innermost layer of the colon, the mucosa, consists of an
epithelial layer composed of columnar absorptive epithelium
and mucin cells intermixed with openings from mucosal
crypts. At the base of these crypts are pluripotent stem cells
that give rise to epithelial cells, which migrate towards the
lumen. The lamina propria is situated between the inner
mucosa and outer muscularis propria and contains much of
the immune cells of the colon along with loose connective
tissue and capillaries. The connective tissue of the lamina
propria does not provide any strength to the intestinal anastomosis [ 2 ]. Lymphatic vessels are located just inside a thin
277
278
N. Smallwood et al.
layer of smooth muscle called the muscularis mucosa. This
smooth muscle layer can undergo isolated thickening in
cases of diverticular disease [
an important part of anastomotic healing and allows for the
normal reparative process to occur much more quickly. An
intact mucosa is important in providing a barrier to bacteria
and other intestinal contents [ 2 ].
3 ]. Apposition of the mucosa is
Submucosa
This is the most important layer of the intestinal wall for the
surgeon. This layer contains the bulk of all collagen found in
the intestinal wall and consists of predominantly type I collagen, with lesser amounts of type III and V [ 3 ]. This layer
provides most of the tensile strength and is the anchor for
holding sutures [
amount of collagen and the degree of cross-linking [
Cross-linking of collagen is dependent on adequate oxygen
tension. Tissues with a PO 2 less than 40 mmHg are unable to
form mature collagen [ 5 , 6 ]. The blood supply of the bowel
terminates in the submucosa and spreads out in a fi ne mesh
of capillaries critical in the delivery of oxygen and nutrients
to the overlying mucosa.
4 ]. The strength is dependent on both the
3 ].
deserosalized areas of the intestine are at higher risk of a leak
[
2 ]. Direct apposition of this layer is therefore very important
in order to promote sealing of the anastomosis [ 9 ]. Small
subclinical leaks may occur even in the “perfect” stapled
anastomosis; yet, adhesions on the serosal surface at the stapled anastomosis may function to seal the anastomosis by
providing serosal gap coverage.
The layers of the intestine are made up of both solid and
liquid elements and can be referred to as biphasic. This principle is important in a stapled anastomosis because pressure
applied to the intestinal wall displaces the liquid component,
resulting in compression and elongation of the solid component, which is known as tissue creep. Compression applied too
rapidly results in shear stress. Optimal stapling consists of
allowing adequate time for tissue compression and creep while
not producing excessive tensile stress [ 10 ]. It is therefore
important to know the appropriate staple height and compression time for a specifi c wall thickness during stapled anastomosis. Sutured anastomoses also require consideration of this
principle since suture depth (ideally in the submucosa) varies
with intestinal wall thickness and water content. Compression
with knot tying can produce tissue tears or fracture.
The Physiologic Perspective
Muscularis Propria
The muscle of the muscularis propria is separated into an
inner circular muscle and an outer longitudinal muscle. The
muscles function primarily for peristalsis. Even though this
layer has some collagen content, it does not provide much
additional strength to the anastomosis. In the chronic obstructive state, the collagen content can signifi cantly increase
along with the thickness of the hypertrophied muscular layers and the overall wall thickness [ 7 ]. In diverticulosis both
layers of muscle are abnormal. The outer longitudinal layer
becomes thickened due to an increase in elastic fi bers, resulting in relative bowel shortening [ 8 ]. The inner circular layer
thickness increases due to its chronic contractile state and
not necessarily from hypertrophy [ 3 ]. Edema tends to sepa-
rate the muscle bundles and weaken this layer. The pathophysiologic changes in diverticular disease and in chronic
obstruction can set the stage for anastomotic failure if the
anastomosis contains any part of this diseased portion, a
largely preventable situation with adequate resection.
Serosa
This outermost very thin layer composed of mesothelial
cells, blood vessels, and lymphatics is most useful in sealing the anastomosis. This is underscored by the fact that
Key Concept : Wound healing at the anastomosis follows a set
pattern similar to other parts of the body .
The GI tract undergoes the process of healing through an
orderly and regulated series of steps designed fi rst to establish an immune barrier and second to repair the injured area
[ 5 ]. These series of steps have been traditionally broken
down into three periods. The phases of infl ammation, proliferation, and remodeling are as applicable to the GI tract as
they are to healing in the skin and other tissues.
I n fl ammatory Phase
The infl ammatory phase, referred to as the lag phase, begins
with an initial hemostatic response and vasoconstriction.
Following this, vasodilation allows for the infl ux and diapedesis of neutrophils. Neutrophils are the predominant cell
within the fi rst 24 h [ 2 ]. The primary role of the neutrophil is
to decrease the bacterial burden of the wound. After the fi rst
48 h, macrophages begin to populate the wound and release
specifi c growth factors, such as platelet-derived growth factor, which allow further progression of the repair [ 5 ]. It is
also during this period that a fi brin seal is formed at the serosal layer allowing for a watertight seal. The clinical signifi cance of this is emphasized by the fact that parts of the GI
tract without the intact serosal layer have a higher incidence
of anastomotic leaks [
2 ].
18 The Failed Anastomosis
279
Proliferative Phase
Infl ux of fi broblasts and the appearance of granulation tissue
mark the beginning of the proliferative phase. The function
of fi broblasts during this phase is highly dependent on certain factors such as fi broblast growth factor and transforming
growth factor beta. Both collagen synthesis and degradation
take place during this period. Collagen breakdown is greater
than synthesis in the fi rst few days (Fig. 18.1 ). The risk of an
anastomotic leak is highest during the fi rst 3 days. Studies
have shown that bursting strength (the amount of intraluminal pressure measured in mmHg needed for anastomotic disruption) is lovest in this time frame [ 2 , 5 ]. It is at this time the
strength of the anastomosis is entirely dependent on the
mechanical strength of the suture or staple relationship with
the adjacent uninjured intestinal wall. This initial loss in
wound strength is much less pronounced in the small intestine. Collagen synthesis begins earlier and to a greater degree
in the small intestine as compared to the colon [ 2 ]. This dif-
ference could explain the higher leak rate in colonic anastomosis (0.9 % vs. 2.4 %) compared to enteric [ 11 ].
Remodeling
The provisional matrix previously formed is remodeled into
a stronger thinner area with fi broblast proliferation and transition in collagen formation from type III to type I [ 2 ]. This
is the time period in which fi broblast-mediated wound contraction occurs. It has been suggested that fi brosis occurs
because of reorganization of granulation tissue into scar that
is likely more pronounced in more ischemic tissue. An
increase in ischemic tissue is one possible explanation for
the higher incidence of stenosis seen with stapled anastomosis compared to hand sutured [
2 , 12 ].
Failed Anastomotic Healing
The healing of the gastrointestinal anastomosis is a timely
and orderly process which occurs successfully the majority
of the time. Failure of this process is caused by local or systemic factors that interrupt the “timely recovery of the injured
tissue’s mechanical integrity [ 13 ].” Tissue perfusion is a
major factor that affects healing locally.
Tissue Perfusion
Key Concept : Macro - and microvascular blood fl ow provide
the necessary factors to enable anastomotic healing . Avoid
using the sigmoid colon , when possible , and fully mobilize
the splenic fl exure to provide a tension - free low colorectal
anastomosis .
For the normal healing process of an anastomosis to take
place, it must have ample tissue perfusion to deliver the
infl ux of infl ammatory cells, growth factors, and oxygen.
Ample tissue perfusion of a healing anastomosis is determined by the macrovascular and microvascular anatomy as
well as the arterial tissue oxygen saturation [ 5 ].
Fig. 18.1 The contribution of anastomotic collagen synthesis and
lysis to overall anastomotic strength (With permission from Munireddy
2 ] )
et al. [
Macrovascular Anatomy
The mucosa, which receives two-thirds of the blood supply of
the colon [ 14 ], is extremely sensitive to reducing blood fl ow.
This leads to ischemia that can rapidly become transmural and
irreversible. In addition, reperfusion of ischemic bowel can
cause further tissue damage that extends beyond the boundaries of the previous injury. The vasculature of the colon and
rectum, along with the multiple variations that exist, is well
known to the surgeon. This knowledge is a necessity in order
to perform a safe and successful oncologic resection, but for
the purpose of the intestinal anastomosis and why it fails, it is
far more instructive to focus on the specifi c areas of relative
vascular insuffi ciency. These areas of vascular insuffi ciency
can be congenital or specifi cally result from surgical resection.
Below are the notable areas of concern.
Griffi ths’ Point
J. D. Griffi ths described a “critical point” that exists at the
splenic fl exure where the marginal artery is often diminished.
The marginal artery in this area is dependent on the left
branch of the middle colic and branches of the ascending left
colic artery to provide blood fl ow [
15 ]. Indeed Griffi ths’ point
280
Fig. 18.2 Images ( a – e ) are
angiographs taken of the entire
colon and rectum. ( a ) Combined
angiographic images of the colon
and rectum. ( b ) Transverse colon.
( c ) Descending colon. In this
portion of the descending colon,
there is wide interspacing between
vasa recta with relative absence of
collaterals at the antimesenteric
border. This is in comparison to the
transverse and right colon (With
permission from Allison et al. [
Arrow indicates point of ischemia in
( b , d )
15 ]).
N. Smallwood et al.
a
b
c
d
is one of the “water shed” areas that develops poor perfusion
during systemic hypotension. This area of the splenic fl exure,
as well as the proximal and mid-descending colon, has also
been shown to contain more widely spaced and infrequent
vasa recta compared to more frequent and one centimeter
apart spacing seen in other areas of the colon [ 15 ] (Fig. 18.2 ).
Griffi ths, along with other surgeons, has recommended that
the branches of the left colic artery be preserved when ligating
the inferior mesenteric artery (IMA) during a sigmoid or
rectal resection [
16 ]. The actual signifi cance of left colic
preservation remains to be proven at this time. It is clear that
e
a decrease in fl ow of up to 50 % can be seen in the marginal
artery after IMA ligation. It should be noted that the area with
the poorest perfusion following IMA ligation will not be the
splenic fl exure but the area involving the sigmoid colon. The
sigmoid colon has a relative defi ciency of the marginal artery
and is the least perfused segment when the IMA is proximally
ligated. Therefore, as long as the sigmoid is resected, ligation
of the IMA proximal to the left colonic branch (high ligation)
should not result in colonic ischemia [
15 , 17 ].
Additionally, the marginal artery of Drummond may
not exist or be patent in a signifi cant number of patients.
18 The Failed Anastomosis
281
The lack of blood fl ow to the left colon, via the marginal
artery from the left middle colic artery, results in ischemia
of the entire left colon after high ligation of the IMA at the
aorta. This will be immediately apparent and should result
in a change in plan to use more proximal colon for a
colorectal anastomosis. It is the author’s opinion that during a low anterior resection, the descending colon should
be used as the proximal end of the anastomosis to the rectum and the splenic fl exure should be routinely mobilized.
In general, high ligation seems safe and potentially provides an oncological benefi t, though one exception should
be noted. Elderly males were shown in one study to have a
much more reduced blood fl ow within the descending
colon following high ligation than females. This is thought
to be due to atherosclerotic changes. Men are known to
have earlier development and more severe atherosclerotic
lesions than do women [ 17 ]. The average age of a man
with newly diagnosed colon and rectal cancer is 69, and
therefore, most men with colon and rectal cancer are at
risk of atherosclerotic lesions. This could explain why the
male gender has been previously shown to be a risk factor
for anastomotic leaks in low colorectal anastomosis.
Elderly males undergoing a low anterior resection who
have evidence of signifi cant atherosclerosis could potentially benefi t from a more distal ligation of the IMA in
order to preserve the LCA and adequate distal perfusion.
Intraoperative evaluation of perfusion could be of use in
this subset of patients.
Sudeck’s Point
This area is described as the point between the last sigmoidal
branch and the left branch of the superior rectal artery [
17 ].
Its main relevance has been seen in episodes of intestinal
ischemia, commonly after abdominal aortic aneurysm repair
and IMA ligation. However, this area may also be of signifi cance if the majority of the sigmoid remains and is used in
the anastomosis following rectal resections. It is therefore
important to avoid using the sigmoid for the anastomosis for
multiple reasons.
Rectal Stump
The rectum has been traditionally viewed as having a robust
blood supply with a rich network of collaterals. This is
based on the clinical fi nding that the rectum, as opposed to
the colon, is very rarely involved in clinical episodes of
intestinal ischemia. In reality, the distal rectum does not
seem to have this robust blood supply nor the same degree
of resistance to ischemia, following a low anterior resection
(LAR). This observation was fi rst described by Goligher in
1949. More recently Allison et al. [
15 ] performed angiog-
raphy of resected specimens’ specifi c reasons for this phenomenon (Fig.
18.3 ). They observed that the upper rectum
had an adequate network of collateral vessels based upon
the superior rectal artery. In contrast, the lower rectum had
a much poorer collateral network that mainly consisted of
intramural vessels. Prior to the LAR, the blood fl ow from
the rectum would preferentially travel down the posterior
left and right branches of the superior rectal artery to end in
the mesentery or rectal wall. The anterior left and right
branches were the only vessels seen to give direct collaterals to the middle and inferior rectal arteries. Following
LAR, the rectal stump is dependent upon fl ow from the
middle and inferior rectal arteries. Angiography performed
on the rectal stump using the middle rectal artery (Fig. 18.3 )
retrograde showed blood fl ow only through the anterior
branch of the superior rectal artery. The posterior rectum
was shown to be dependent upon a variable amount of
intramural collaterals between the anterior and posterior
branches. This results in a poorly perfused posterior-inferior rectal stump, and is likely why it is not too uncommon
for leaks to occur at the posterior aspect of the anastomosis
15 ]. Another report did not show decreased perfusion spe-
[
cifi cally in the posterior-inferior rectum, but the rectal
stump had a greater reduction in blood fl ow as compared to
the proximal end [
18 ]. In addition they found signifi cantly
more leaks in those patients where there was a blood fl ow
reduction of 16 % or greater [ 18 ].
Microvascular Anatomy
Small vessel collaterals can be of signifi cance at specifi c
locations of the colon and rectum. Just as a decrease in the
number of these collaterals can affect local tissue perfusion,
local vasomotor control over these collaterals can also have
a profound effect. This is most profound when splanchnic
vasoconstriction occurs in the setting of blood loss and hypotension, as well as increased sympathetic activity, and can
dramatically impact the healing anastomosis.
Arterial Oxygen Tension
As humans we are obligate aerobes. In addition to aerobic
metabolism, oxygen is needed in collagen synthesis; however, when the oxygen tension drops below 40 mmHg, collagen synthesis ceases [
5 ]. The amount of oxygen that is
delivered to the tissues is dependent upon a multitude of factors that includes cardiac output, local vascular resistance,
and hemoglobin content. Both cardiac output and local vascular resistance have a more profound impact on tissue oxygenation than hemoglobin as only a mere half of all
oxygen-carrying hemoglobin is needed at any point in time
for aerobic metabolism [
19 ]. As such, anemia in and of itself
is less likely a major contributing risk factor of anastomotic
leaks.
Summary Pearl
Currently the list of identifi ed risk factors for anastomotic
leaks is extensive, and their exact relationship to, and signifi cance in, anastomotic leaks is hard to defi ne. You are
therefore faced with a complex array of risk factors, all
282
Fig. 18.3 The superior rectal artery
(SRA) divides into a right and left
branch in the upper mesorectum.
Both the right and left branch give
off smaller anterior and posterior
arteries that supply the rectum. Only
the anterior branches communicate
directly with the middle rectal artery
(With permission from Allison et al.
15 ]). ( a ) Injection through middle
[
rectal artery. After rectal resection
and sacrifi ce of the SRA, blood
preferentially fl ows down the
anterior branches ( a ) to the
bifurcation point in the upper
mesorectum. Blood then travels
antegrade down the posterior
branches ( P ) to the posterior portion
of the rectum. ( b – d ) Rectal
resections distal to the SRA
bifurcation prevent direct fl ow from
the anterior branches (1) to the
posterior branches. Instead, the
posterior rectum must rely on small
vessel intramural collaterals (2) and
inferior collaterals of the posterior
branches (3) Arrows indicates blood
fl o w
N. Smallwood et al.
a
b
c
with varying degrees of importance, affecting to some
degree one or more components of anastomotic healing,
and you must decide which one is at play in a particular
patient.
Risk Factors
Key Concept : Risk factors for anastomotic leak fall into the
three broad categories : patient - related , location - related , and
intraoperative factors . Knowledge of such risk factors should
d
ultimately provide the basis of future preventive techniques
while currently highlighting those patients in whom proximal diversion may be warranted .
Patient-Related
Key Concept : Certain inherent risk factors are present with
every operation , though identifying and targeting modifi able
risk factors , when possible , may mitigate the development of
leaks .