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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_670_Библиотеки_им_академика_М_И_Перельмана
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Operations for Chronic Mesenteric Ischemia
Operative Indications
Despite the widespread and increasing use of high resolution imaging
such as CT and MRI scanning, the diagnosis of chronic mesenteric
ischemia remains elusive. Symptoms of food fear due to abdominal
discomfort often slowly limit dietary intake to such a degree that
classic symptoms of post-prandial pain and bowel habit
change may be absent. Weight loss may also be variable,
particularly in the elderly, and be assigned to other
causes before the possibility of vascular insufficiency is
entertained. The atherosclerotic plaque is most often
isolated to the origin of the mesenteric vessels. In the
celiac axis, relative less atherosclerotic burden may be
exacerbated by chronic compression of the origin by
muscular fibers of the diaphragmatic crus (median arcu-
ate ligament syndrome). Symptoms of chronic mesen-
teric ischemia are rare unless two of the three vessels (celiac,
Celiac a.
(compressed)
SMA
IMA
superior mesenteric, and inferior mesenteric arteries) develop
severe arteriosclerotic lesions or occlusions (1).
1
Operations for Chronic Mesenteric Ischemia 293
The goal of the operation is to achieve complete revascularization of the mesenteric blood supply. While this may be
achievable with direct revascularization of the SMA alone, better immediate symptom relief and long-term freedom from
recurrent symptoms of mesenteric ischemia are appreciated when two mesenteric vessels are revascularized. Suitable sites of
aortic origin of the vascular reconstruction should be considered based on arteriography and axial imaging to seek healthy,
non-diseased segments to prevent atheroembolization into the graft.
Operative Technique
The patient is positioned supine for a long midline incision to fully exam-
ine the small and large bowel. A roll may be placed transversely under
the upper lumbar vertebrae to angle the costal margin upwards, thus facil-
itating the dissection of the diaphragmatic hiatus and the upper abdomi-
nal aorta and its branches. The transverse mesocolon is mobilized cephal-
ad. By completely releasing the ligament of Treitz, the duodenum can be
mobilized, exposing the left side of the SMA to the aorta (2). In this
location, the artery is larger than the more distal inframesocolic site used
for clot removal, and a patulous anastomosis may be constructed.
SMA
Pancreas
elevated
Ligament of
Treitz (divided)
2
294 Atlas of Gastrointestinal Surgery: The Small Bowel
Transverse
colon
Duodenum
SMV
Small bowel retracted
to the patientʼs right
Aorta
Plaque in SMA
Pancreas
Lig. of Treitz (divided)
Left renal vein
Retropancreatic
tunnel
An end-to-end anastomosis from
the prosthetic graft to the open end of
the SMA may be created if the pancreas
can be retracted in a cephalad fashion suf-
ficiently to allow circumferential exposure
of the proximal SMA. When the proxi-
mal arteriosclerotic plaque involves a
long segment of the proximal SMA,
an end-to-side anastomosis may be
required to preserve branches prox-
3
imal to, or within, the anastomosis,
which require reperfusion. The tun-
nel of the vascular graft will be
placed anterior to the left renal vein
and SMA, and under the pancreas as
depicted by the black arrow (3).
Graft site on
supraceliac aorta
Operations for Chronic Mesenteric Ischemia 295
To access the supraceliac aorta, the triangular ligament is
incised and the left lobe of the liver is retracted. The lesser
omentum is opened, and the stomach is retracted caudally
and to the left. By opening the diaphragmatic crus, the
crossing fibers over the celiac axis can be released and
8–10 cm of aorta exposed for application of a Lemole
aortic clamp to partially occlude the aorta. In comparison
to the infrarenal aorta, the supraceliac aorta is often free of
Graft site on
hepatic a.
Graft site on
SMA
significant degeneration that would make “side biting”
prone to cause clamp-related atheroembolization. In
addition, the diameter is larger, thus reducing hemo-
dynamic perturbation due to the partial occlusion
technique.
A bifurcated Dacron or PTFE graft can be used,
most often in 14 X 7 mm or 16 X 8 mm configuration.
Once the targets for revascularization of the hepatic
artery and SMA are identified, the retropancreatic
tunnel is created and the patient is systemically anti-
coagulated with intravenous heparin. The supraceli-
ac aorta is then controlled with a Lemole partial
occlusion clamp (4). The segment of aorta within the
clamp is punctured with an 18 or 20 gauge hypodermic nee-
4
partial occlusion clamp must be tightened or abandoned for a
complete aortic cross clamp for vascular control.
dle to assess hemostasis. If pulsatile bleeding is noted, then the
296 Atlas of Gastrointestinal Surgery: The Small Bowel
Aortic
anastomosis
The aortic anastomosis is performed with minimal
graft beveling and 4-0 synthetic nonabsorbable
End-to-end
anastomosis
(hepatic a.)
Short, ostial plaque
in SMA
End-to-end
anastomosis (SMA)
suture. Revascularization of the hepatic artery is
performed in an end-to-side fashion.
If the SMA trunk is long and distally
uninvolved by plaque, an end-to-end aorta-
SMA anastomosis is performed, with 5-0
synthetic nonabsorbable suture (5).
5
When the SMA plaque is long and
extensive, and end-to-side aorta-SMA anas-
tomosis is required (6).
End-to-side
anastomosis
Long, complicated
plaque in SMA
6
Operations for Chronic Mesenteric Ischemia 297
Celiac Endarterectomy and SMA Bypass
Poor upper abdominal exposure, often due to a
narrow angle of the costal margins or obesity,
Celiac plaque
removed
Hepatic a.
clamped
L. gastric a.
divided
Splenic a.
clamped
may preclude mobilization of a sufficient
length of supraceliac aorta. In these cases,
partial aortic occlusion around the celiac
origin is an option. By sacrificing the
left gastric artery, dissecting the hepat-
ic and splenic arteries laterally, and
mobilizing the pancreas caudally, the
Lemole clamp can surround the celiac
axis origin with a wide margin of aorta.
A longitudinal aortotomy is then
extended onto the celiac trunk. The
plaque within the celiac trunk is freed using
an endarterectomy spatula to restore the celiac
trunk luminal diameter. Proximal anastomosis to an
8-mm Dacron or PTFE tube graft, beveled with appropri-
ate angle to facilitate entry into the retropancreatic tunnel, can
be carried onto the proximal aorta and across the celiac
endarterectomy (7).
7
298 Atlas of Gastrointestinal Surgery: The Small Bowel
The heel of the anastomosis is
secured first with accurate place-
ment of the 4-0 synthetic non-
absorbable suture to avoid nar-
SMA
End-to-end
retropancreatic
anastomosis
to SMA
rowing the inflow under the
heel of the graft into the celi-
ac axis. The suture line is then
completed in a running fashion
onto the aorta.
The SMA anastomosis is per-
formed in an end-to-end configura-
tion with 5-0 synthetic nonabsorbable
suture (8) after division distal to the SMA
arteriosclerotic lesion.
The bowel should be assessed for viability prior to
closure. If a suspicious segment is identified, perfusion can
be further assessed with peripheral intravenous injection
of sodium fluorescein (500–1000 mg) and
Wood’s lamp illumination.
8
THE COLON
Overview of the Anatomy of the Colon
The colon extends from the ileum to the anus and is approximately 1.3 m in length. It is divided into the cecum, the
ascending colon, the transverse colon, the descending colon, and the sigmoid colon. Much of the colon and its mesen-
tery, or mesocolon, is invested in peritoneum making it a retroperitoneal structure. The transverse colon and the sigmoid
colon are the most mobile segments of the colon. In contrast to the small intestine, the colon can be identified by its sac-
culations, appendices epiploicae, and longitudinal bands, or taenia coli.
Due to its embryologic development, the blood supply to the colon arises from the superior mesenteric artery (midgut)
and the inferior mesenteric artery (hindgut). The superior mesenteric artery supplies the cecum, the ascending colon, and
the transverse colon via the ileocolic, the right colic, and the middle colic arteries, respectively. The origin of the right colic
artery is the most variable of all vessels supplying the colon. This artery may come directly off the superior mesenteric artery,
or arise from the ileocolic or the middle colic artery or may be entirely absent in up to 20% of individuals.
The descending colon, the sigmoid colon, and the rectum receive their blood supply from branches of the inferior
mesenteric artery. This artery arises approximately 3 to 4 cm proximal to the bifurcation of the aorta into the common
iliac arteries. Shortly after its origin, the inferior mesenteric artery divides into the left colic artery and the sigmoidal
branches. The left colic artery gives way to an ascending branch, which courses superiorly to supply the descending colon
and unites with the middle colic artery, forming the arcade of Riolan. The descending branch of the left colic artery joins
the sigmoidal arteries. The sigmoidal branches, of which there are typically two or three, supply the sigmoid colon. The
middle colic artery and left colic artery further join to give rise to the marginal artery of Drummond, which runs parallel
to the colon to the level of the rectosigmoid junction. In performing a coloanal anastomosis, the inferior mesenteric artery
must be divided to give sufficient length to the bowel. The viability of the remaining distal colon is therefore dependent
on the marginal artery (1).
The venous drainage of the colon parallels the arterial blood supply with the exception of the inferior mesenteric vein,
which courses superiorly in the left medial location until it joins the splenic vein, posterior to the pancreas.
The lymphatic drainage and the parasympathetic and sympathetic innervation of the colon follow the vascular supply as
well. The lymph nodes within the mesentery of the colon are traditionally divided into four groups: the epiploic, the para-
colic, the intermediate, and the principal nodes. The epiploic nodes are closely associated with the bowel wall; the para-
colic nodes are associated with the marginal artery; the principal nodes are located at the origin of the major vessels of the
large intestine; and the intermediate nodes lie between the principal and the paracolic nodes. The entire colon may be
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