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23
Mesenteric considerations in ileal pouch
analanastomosis
J. CALVIN COFFEY AND JAMES W. OGILVIE JR.
Process makes you more efcient.
Steve Jobs
AIMS
To demonstrate the importance of mesenteric and peri-
toneal factors in constructing and anastomosing an ileal
pouch to the anal canal.
INTRODUCTION
Ileal pouch anal anastomosis (IPAA) is generally performed
in two or three stages. In the two-stage procedure, a total
mesocolectomy, proctectomy, ileal pouch formation and
loop ileostomy are rst conducted. e stoma is reversed ata
later time point. e three-stage procedure usually follows
emergency subtotal colectomy. In the second stage, the rec-
tum is removed, an ileal pouch and covering loop ileostomy
constructed. Most surgeons currently do not advocate a
one-stage total mesorectal and mesocolic excision followed
by IPAA without covering loop ileostomy [1–7]. Proceeding
chapters have described total mesocolic and mesorectal
excision and so the reader is referred to these as an intro-
duction to the present chapter.
A number of mesenteric principles should be adapted
in ileal pouch formation and anastomosis (Figure 23.1).
First, it is absolutely required that the intestinal and mes-
enteric complex of ileum and mesentery be able to reach
the pelvic oor comfortably without mesenteric tension.
is is an important early consideration as it is preferable
to identify problems with reach before pouch formation.
Some bowstringing is inevitable following ileal pouch–
anal anastomosis but this does not appear (as yet) to
impair pouch function. In order to reach the divided distal
rectum (Figure 23.2), the small bowel mesentery must be
mobilized off the retroperitoneum, as far proximally as
the root region of the mesentery. As a result, the reec-
tion at the base of the small intestinal mesentery must be
divided up to the fourth part of the duodenum. Division
of the reection exposes the mesofascial interface enabling
separation of its components and detachment of the mes-
entery from the retroperitoneum, without disruption of
either. Itmay also be necessary, at the fourth part of the
duodenum, to divide congenital adhesions between this
and residual le mesocolon.
Problems with reach can persist despite the above
measures. One means of overcoming these is to carefully
divide the ileal mesentery between vessels. is should be
done aer rst back-lighting the mesentery to identify the
vessels. Any mesenteric windows should be created away
from the intestinal margin of the mesentery. Positioning
them in this manner helps increase mesenteric reach.
Although the right mesocolon should also be absent
(assuming a total mesocolectomy was conducted in the rst
instance), residual mesocolon can still be present in some
cases. A problem arises here in so far as the small intesti-
nal mesentery is continuous with the right mesocolon. is
means the residual right mesocolon must be mobilized o
the retroperitoneum for complete mesenteric mobilization.
Adhesions from previous surgery can render this techni-
cally challenging. Some surgeons divide the small bowel
mesentery as close to the ileocecal junction as possible
while others divide the mesentery high-up on the ileoco-
lic vascular pedicle. It is not known whether this preference
is associated with diffe ential rates of adhesion formation.
Notwithstanding the above considerations, and provided
the surgeon identifi s and follows the mesofascial interface,
then it is usually possible to safely and quickly mobilize the
entire mesentery.
Aims 317
Introduction 317
Summary 321
References 321
318 Mesenteric considerations in ileal pouch analanastomosis
Care must be taken at the root region given the superior
mesenteric vein and artery, as well as lymphatic and neuro-
logic structures, are bundled here. e entire mesentery fans
out from the root region. Indiscriminate and nonanatomic
dissection in this region increases the risk of catastrophic
small intestinal devascularization.
As mentioned earlier, the surgeon must have a clear
understanding of mesenteric anatomy. Th s need increases
further given the frequency of adhesions that occur with
open surgery. It is not uncommon to fi d residual left meso-
colon adherent to small bowel mesentery. When this occurs,
retroperitoneal structures (i.e., ureters and gonadal vessels)
may be pulled into a nonretroperitoneal location. Th s is
particularly important in the context of pouch excision or
reoperative pouch surgery, where the surgeon must conduct
an extensive and widespread adhesiolysis in as safe a man-
ner as possible. To achieve this, the surgeon must be able
to dierentiate mesenteric from adhesional, omental, and
mesocolic fatty structures.
When the ileal pouch itself is formed, it is important
not to include mesentery in the staple lines. To prevent
Rectum stapled just above anorectal junction
Distal rectum followin
g
staple division
Figure 23.2 Intraoperative image demonstrating the
stapled-divided anorectal junction as observed using the
UL exoscope.
The anorectal junction
Staple division of anorectal junction
Distal
rectum
(a)
(b)
Anterior
mesorectu
m
Figure 23.1 (a) Intraoperative image demonstrating the mobilized rectum, just above the anorectal junction, as seen
usingthe UL exoscope during open colorectal surgery. (b) Intraoperative image of same region as in (a) after application
of stapling device (in this case a TA45).
Introduction 319
this, the pouch is positioned with the mesentery facing
posteriorly toward the retroperitoneum (Figure 23.3).
Some advocate positioning of the pouch such that the
mesentery takes up a position anterior to the pouch.
Ifthe pouch is created using a stapling device, then the
surgeon places his/her hand posteriorly, aer device
closure, to ensure the mesentery has not been included in
the staple line (Figure 23.4).
Once the ileoanal anastomosis has been completed,
the staple line can be reinforced using interrupted 3.0
Vicryl
®
or PDS
®
sutures (Figure 23.5a). In general, surgeons
use a stapling technique whereby an anvil is placed into the
pouch, secured with a 2.0 Prolene
®
purse string suture,
and then docked in the shaft of the circular stapling device
(which was inserted transanally below). Prior to ring the
device the mesentery is inspected to ensure it has not been
twisted (Figure 23.5b). e mesentery must be inspected
proximally as far as the DJ exure. If a mesenteric twist is
identifi d, theanvil is disengaged, the mesentery unwound,
and the docking procedure repeated (Figure 23.5b).
Orienting ileum with mesentery posterior
Mesentery
positioned
posteriorly
Measuring pouch length
(a)
(b)
Measuring afferen
t
and efferent limbs
of pouch
Figure 23.3 (a) Intraoperative appearance of the terminal ileum after the mesentery has been orientated posteriorly and the
ileum folded back on itself. Surgeons differ in relation to the optimum length with most recommending lengths between 15
and 20 cm. (b) Intraoperative demonstration of the usage of the ruler to decide on the length of each pouch limb.
320 Mesenteric considerations in ileal pouch analanastomosis
Enterotomy at apex of ileal pouch at antimesenteric border
(a)
(b)
Anti-mesente
ry
enterotomy
Staple-anastomosis of ileal limbs; mesentery positioned posteriorly
Ileo-ileal
stapling
Mesentery
placed
posteriorly
Ileum
intussuscepted
over staple ar
ms
Figure 23.4 (a) Creation of enterotomy on the antimesenteric border of the ileum. This permits insertion of the
staplingdevice. It is important to place the enterotomy at this location as placement too near the mesenteric border could
compromise blood supply after the staple anastomosis. (b) Insertion and engagement of the stapling device ensuring that
the mesentery is orientated posteriorly. In this manner, one ensures that the mesentery is not included in the staple line.
References 321
SUMMARY
A key point in IPAA formation is the generation of su-
cient intestinal and mesenteric reach to enable a tension-free
anastomosis. e mesentery must be protected at several
points in the procedure.
REFERENCES
1. Davies, M. and P.R. Hawley, Ten years experience of
one-stage restorative proctocolectomy for ulcerative
colitis. Int J Colorectal Dis, 2007. 22(10): 1255–126 0.
2. Heuschen, U.A. etal., One- or two-stage procedure
for restorative proctocolectomy: Rationale for a
surgical strategy in ulcerative colitis. Ann Surg, 2001.
234(6): 788–794.
3. Ikeuchi, H. etal., Safety of one-stage restorative
proctocolectomy for ulcerative colitis. Dis Colon
Rectum, 2005. 48(8): 1550–1555.
4. McGuire, B.B., A.E. Brannigan, and P.R. O’Connell,
Ileal pouch-anal anastomosis. Br J Surg, 2007. 94(7):
812– 823.
5. Remzi, F.H. etal., The outcome after restorative
proctocolectomy with or without defunctioning
ileostomy. Dis Colon Rectum, 2006. 49(4): 470–477.
6. Sugita, A. etal., Reconstruction of proctocolectomy:
Which is the best surgical procedure? Nihon Geka
Gakkai Zasshi, 2008. 109(5): 269–273.
7. Swenson, B.R. etal., Modied two-stage ileal pouch-
anal anastomosis: Equivalent outcomes with less
resource utilization. Dis Colon Rectum, 2005. 48(2):
256 –261.
Reinforcing staple line with sutures
(a)
(b)
Suture
reinforcement
of staple lines
Ileo-anal anastomosis; mesentery positioned posteriorly
Aligned ileo
-anal
anastomosis
Ileal
mesente
ry
Ileum
Figure 23.5 (a) Suture reinforcement of the ileoanal staple line. (b) Intraoperative appearance of the ileoanal anastomosis
following stapling, as seen using the UL exoscope. The mesentery is positioned posteriorly and the ileum and anal canal
are aligned without torsion. These features are readily conrmed using the exoscope.
323
24
Mesenteric considerations in
ostomyformationand reversal
J. CALVIN COFFEY, COLIN PEIRCE, AND ANN BRANNIGAN
Science never solves the problem without creat-
ing ten more.
George Bernard Shaw
AIMS
is chapter aims to demonstrate the mesenteric and peri-
toneal factors involved in stoma formation and reversal.
INTRODUCTION
e following chapter will focus on the mesenteric and
peritoneal components of stoma formation and reversal.
It is divided into two sections. e rst focuses on stoma
formation and reversal in general. e second focuses on
particular challenges and the eff cts of mesenteric and peri-
toneal factors on these. Stoma formation and reversal are
extremely important techniques. If completed incorrectly,
the results can be devastating for patients faced with a per-
manent stoma [1].
STOMA FORMATION AND REVERSAL
Ileostomy formation
THE STOMAL APERTURE IN GENERAL
is must be wide enough to ensure that mesenteric vas-
culature is not compromised. In addition, the intestinal
and mesenteric complex must come through in a vertical
rather than an oblique orientation. As the intestinal tract is
itself collapsible, then the defect in the anterior abdominal
wall must be suciently large as to admit the mesenteric
bulk associated with that segment of intestinal tract. ere
are several approaches to ensuring this. One includes the
placement of two clamps (one vertically above the other)
on the fascia and skin of a laparotomy. ese are used to
ensure that the layers of the stoma channel, when fash-
ioned, are vertically stacked. Adisc of skin is excised, and
Langenbachs are used to displace the subcutaneous tissue
to expose the fascia (Figure24.1). Importantly, the former is
not excised. e fascia is sharply opened longitudinally, and
the muscle bers of the rectus sheath are separated but not
divided (Figure24.1). e underlying fascia is exposed and
can be sharply divided through onto a folded swab placed
beneath. Ideally, the aperture so created should easily permit
two digits of a size eight glove [2–5]. is approach ensures
a vertically oriented stomal channel sucient in caliber to
admit the intestinal and mesenteric complex without com-
promise of mesenteric vasculature (Figure 24.1).
DELIVERING THE INTESTINE AND MESENTERY
COMPLEX THROUGH THE STOMA
If the stoma aperture has a vertical orientation, then the
bowel and associated mesentery can be delivered through
with minimal trauma to either component. ere are several
means by which this can be achieved. One method involves
placing a nylon tape across the mesentery, just beneath the
Aims 323
Introduction 323
Stoma formation and reversal 323
Ileostomy formation 323
The stomal aperture in general 323
Delivering the intestine and mesentery
complexthrough the stoma 323
Stomal eversion 325
Ileostomy reversal 325
Special considerations 330
Ileostomy formation 330
Ileostomy reversal 330
Transverse loop colostomy formation 330
Difculty mobilizing the transverse colon 331
Summary 331
References 331
324 Mesenteric considerations in ostomyformationand reversal
Excision of skin only
Ileostomy formation; mesenteric and peritoneal basis
(a)
Dissection of skin
Rectus
Posterior fascia
Swab
Kocher clamp ”unwinding” throughnylon tapeKocher clamp
(b)
(c)
(d)
(e) (f )
Figure 24.1 (a) Disc of skin shaped using the diathermy. (b) The skin (and not the underlying subcutaneous tissue)
isexcised. The subcutaneous fat will conform to the shape of the gastromesenteric complex and form an adipose collar
around it. (c) Intraoperative view of muscle bers after their splitting and retraction to expose the underlying rectus
sheath. (d) Intraoperative view of the swab held up against the anterior abdominal wall, after division of the rectus sheath
onto the swab. (e) Nylon tape–based technique to unwind the Kocher clamp through the mesentery in an atraumatic
manner. (f) The Kocher clamp can then be used to withdraw the rod back through the mesenteric channel. The mesenteric
channel was created in an atraumatic manner and thus facilitates atraumatic withdrawal through of the rod.
Stoma formation and reversal 325
serosa, and using this to draw both structures through the
channel, to the surface. e intestine and mesentery are
helped through by exerting gentle traction on the nylon tape
from outside, and additional gentle manual encouragement
from the inside.
e nylon tape must be placed across the mesentery in
as atraumatic a manner as possible. is can be achieved by
exploiting the fact that if the tip of an artery clip is pressed
gently against the gastromesenteric interface, it will emerge
through the point of least resistance, that is, where only
connective tissue connects both interface components.
A nylon tape is then grasped and the clip and tape with-
drawn back through to the starting side of the mesentery
(Figure24.1eandf).
When the intestine and mesentery have been deliv-
ered to the surface, the surgeon must ensure they have not
been twisted. Overt torsion is easily recognized but minor
degrees may go unnoticed and lead to delayed recovery. If
the mesentery has not been twisted, then by denition the
intestine is also not twisted.
To fully secure the stoma in place, a rod is generally
placed beneath it. is must also be drawn across the mes-
entery in an atraumatic manner. One means of achieving
this is to grasp the nylon tape with a Kocher clamp and draw
the clamp across the junction between mesentery and intes-
tine. As the clamp is coming through, it should be rotated
through a spiral path and not brought through directly.
Rotating the clamp helps reduce mesenteric trauma. Once
through, the Kocher clamp will have created a mesenteric
channel the width of which will accommodate a rod. e
rod is grasped, and the rod/clamp complex withdrawn back
across the mesentery. During this, the clamp is turned in
the opposite direction to that in which it was originally
rotated as it crossed the mesentery (Figure 24.1e and f).
STOMAL EVERSION
To prevent mesenteric and intestinal dehydration and ssur-
ing, the intestine must be everted over the mesentery. In the
case of a loop ileostomy or colostomy, this can be achieved
by taking the following precautions. First, a transverse enter-
otomy is created at the distal (eerent) pole of the intestine,
near ush with the skin. e enterotomy can be ush as
minimal small bowel content will emerge from this pole of
the stoma (Figure 24.2). e enterotomy is readily secured
in position by suturing the intestine full thickness, to the
dermis of the skin, at three compass points.
e affe ent pole must be everted in order to cover the
serosa and subjacent mesentery. A suture is placed full
thickness through at the compass points, then though the
dermis of the skin, and each placed on a clip (Figure24.2).
e affe ent pole of the intestine will automatically start to
evert. Full eversion is achieved by tying down the sutures
and simultaneously placing the blunt end of a forceps
underneath the intestine (Figure 24.2). At completion of
eversion, there should be mucocutaneous apposition cir-
cumferentially, with minimal serosa or mesentery exposed.
e mesenteric and peritoneal principles of end ileos-
tomy/colostomy and loop colostomy formation are similar.
As a result, these will not be described separately.
Ileostomy reversal
As mentioned earlier, all stomas have intestinal and mesen-
teric components. e key to stoma reversal is safe mobi-
lization of both with minimal trauma to either. Avoiding
trauma to the mesentery can be rendered dicult for two
reasons. First, mesenteric and subcutaneous fat are simi-
lar and oen densely adherent in the setting of a stoma. To
overcome this, the surgeon should aim to dissect directly
onto the serosal surface of the intestine, once this has been
partially detached from the surrounding skin and subcu-
taneous tissue (Figure 24.3). Following the serosal surface
circumferentially facilitates identifi ation of the mesen-
tery and its dierentiation from adjacent subcutaneous fat
(Figure 24.3). If the surgeon does not dissect directly onto
the serosa, then he or she may inadvertently dissect through
mesenteric fat. Th s is invariably followed by bleeding, and
in an eort to gain hemostasis, mesenteric vasculature may
be ligated.
A second diculty arises at the fascial/stomal aper-
ture, where a band of peritoneum invariably bridges the
space between the serosa/mesentery and the defect itself
(Figure 24.3). Once this has been divided through, the
surgeon enters the true peritoneal cavity. e problem
is that the peritoneum at the abdominal wall defect is
draped up onto the mesentery or serosa to which it adheres
(Figure 24.3). Regions of adhesion must be identifi d so
that the interface components can be anatomically sepa-
rated. is can be identifi d by placing a Kocher clamp
on the fascial defect and using this to generate traction.
Countertraction placed on the intestine/mesentery then
exaggerates the adhesion and permits identication of the
peritoneum.
Once the stoma has been fully detached at all lev-
els down to the peritoneal cavity, it must be separated
to clearly demonstrate all intestinal and mesenteric
anatomy. If this is not done, then serosal tears, enteroto-
mies, or regions of mesenteric devascularization will be
missed. This process involves division of all adhesions
(Figure 24.4) including those between the bowel and
mesentery and those between adjacent regions of mes-
entery (Figure 24.4). Once the anatomy of the intestine
and mesentery is fully apparent, the everted afferent pole
must be reversed by sharp division of adhesions between
the skin and serosal surface (Figure 24.5). Next, the col-
lar of skin is excised and the surgeon assesses for any
residual serosal tears or enterotomies. The stoma enter-
otomy is then closed using interrupted sutures that invert
the mucosa and achieve sero-serosal apposition. Both
conditions (i.e., inversion and sero-serosal apposition)
are important to achieve and prevent anastomotic leak-
age (Figure 24.5).