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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_627_Библиотеки_им_академика_М_И_Перельмана
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FIGURE 21-6 Isolation of the inferior mesenteric artery at its origin off of the aorta.
Suture ligature is applied, and the artery and vein occasionally can be
ligated in the same suture.
In laparoscopic cases, the peritoneum is incised medially beginning at the
sacral promontory and is carried to the level of the IMA as it comes off the
aorta (Fig. 21-7).
FIGURE 21-7 Isolation of the inferior mesenteric artery (IMA) at its origin off of the
aorta during laparoscopic surgery; notice the dissection window created to the right of the
IMA in which retroperitoneal structures are swept down.
At this stage, any lateral attachments/adhesions are generally not dissected
and instead kept in situ to aid in retraction of the left/sigmoid colon.
The IMA is skeletonized and is divided with an energy device;
alternatively, clips or a stapler may be applied (Fig. 21-8).
FIGURE 21-8 Laparoscopic energy device to ligate the inferior mesenteric artery.
After the IMA and IMV have been ligated at this level, dissection is
carried toward the fourth portion of the duodenum and ligament of Treitz.
The IMV can be found just lateral to the duodenum and proximal to the
inferior edge of the pancreas before it joins the splenic vein to become the
portal vein.
It is our routine practice to ligate the IMV at this level to allow
excellent reach of the colonic conduit into the pelvis for a tension-free
anastomosis (Fig. 21-9).
FIGURE 21-9 Isolation of the inferior mesenteric vein.
When the IMA is ligated at its origin and the IMV is ligated at the
pancreatic level, the proximal blood supply to the anastomosis is
supplied via the marginal artery of Drummond by way of the middle
colic vessels (Fig. 21-10).
FIGURE 21-10 High ligation of the inferior mesenteric vein at the level of the
pancreas, lateral to the ligament of Treitz.
When these high ligation maneuvers are employed, it is rare that the colon
will not adequately reach into the pelvis.
Left Colon and Splenic Flexure Mobilization
Medial-to-lateral dissection proceeds after the IMA/IMV have been
ligated.
Although the lateral-to-medial approach may pose to be less difficult in
open surgery, this author, for oncologic purposes, utilizes a medial
approach first for all cases.
The retroperitoneal structures, including the ureter, gonadal vessels, and
the psoas muscles, are swept posteriorly, and the dissection is carried
laterally to the abdominal wall, over Gerota fascia/perinephric fat, and
toward the spleen.
Next, the lateral dissection begins at the iliac fossa and continues
superiorly toward the splenic flexure.
The dissection is carried 1 mm medial to the white line of Toldt (ie, the
white line should stay with the patient) until the spleen is reached.
The splenic flexure is mobilized carefully in order not to cause splenic
capsular tear or colonic wall damage.
Gentle traction on the colon medially will allow for the splenocolic and
retroperitoneal attachments to be safely and sharply dissected free (Fig.
21-11).
FIGURE 21-11 Mobilization of the splenic flexure. Gentle medial traction is placed
on the colon and the peritoneal attachments are divided.
If this approach becomes too difficult, we often will enter the lesser sac
where the omentum attaches to transverse colon and mobilize the colon
toward the spleen to meet up with the previous dissection plane.
Routine separation in the avascular plane between the transverse
mesocolon and the greater omentum is compulsory for proper reach into
the pelvis.
TIPS
Care should be taken to ensure proper mobilization of the posterior
retroperitoneal (ie, pancreatocolic) attachments.
Preparation of the Proximal Colon and Distal Transection
In laparoscopic cases, distal transection is performed before the colon is
exteriorized.
The endoscopic linear stapler is placed through the right lower 12-mm
port.
The posterior mesorectum on the upper rectum is cleared, and ideally, a
single firing of a 60-mm linear stapler should be all that is needed to fully
transect the bowel; occasional use of another staple load is needed in a
thicker or large diameter rectum (Fig. 21-12).
Care is taken to avoid damage to the rectal wall during the fat clearing.
This is facilitated by mobilizing the fat from the posterior wall and then
dividing the mesorectum with the posterior rectal wall in direct vision.
FIGURE 21-12 Endo-GIA 60-mm stapler via the right lower 12-mm port site in
order to transect the upper rectum.
In open cases, distal transection follows proximal transection in most
instances.
Once the proper distal transection site on the rectum has been established
based on margin status, the use of a 45- or 60-mm stapling device is most
often employed when performing a double-stapled anastomosis.
The entire circumference of the transection site should be cleared of
any mesorectum, lateral attachments, and anterior structures.
If too much material is placed in the stapler at one time, it will not fire
properly.
An off-midline extraction (ie, left lower quadrant or planned ostomy site)
site is preferred by many due to a potential in decreased hernia formation
and wound infection rates, although hernia rates may be higher when
umbilical extraction sites are chosen.
Pfannenstiel or periumbilical extraction sites can also be used with good
results.
Wound protectors are used for all extractions, regardless of technique
employed.
Before making a colorectal anastomosis, the distal colonic conduit must
have adequate perfusion.
As mentioned previously, since the IMA has been divided in a high
ligation manner, the proximal blood supply is based on the marginal artery
via the middle colic artery.
It is routine to sharply transect the marginal artery near the site of the
future purse-string suture in order to check for good vascular perfusion.
Pulsatile bleeding from the marginal artery is best, but a good, steady
flow is adequate. Essentially, if one has to clamp and ligate the
marginal artery, it will provide adequate perfusion for the anastomosis.
The use of immunofluorescence is not routinely used at present in our
institution, and it may be considered as an adjunct if deemed necessary
in select cases where perfusion is in question.
After assuring a well-perfused conduit, a handsewn purse-string suture of
0-polypropylene monofilament is placed with careful attention to include
the seromuscular layer of the bowel wall.
Shallow mucosal bites are taken in order to avoid too large a “donut”
for the circular stapler.
The appropriate size anvil for the double-stapled anastomosis is then
placed in the lumen and tied snugly into place.
The largest size anvil and stapler that is able to be accommodated by
both the proximal colon and the anus is recommended.
It is routine by this author to not use anything less than a 31-mm end-
to-end stapler, if possible (Fig. 21-13).
FIGURE 21-13 Distal transection of the upper rectum with 60-mm linear stapler.
TIPS
Only one staple load should ever have to used, if proper dissection has
been performed in this critical portion of the operation.
Colorectal or Coloanal Anastomosis
Traditional end-to-end double-stapled circular anastomosis is preferred.
Regardless of stapled anastomotic technique, the fundamentals of stapler
use hold true for all reconstruction techniques.
Upon gently placing the stapler per anus, it is carefully advanced
passed the sphincter mechanism to the rectal staple line.
The spike is advanced at or just anterior/posterior to the staple line.
Individual surgeon preference exists regarding anterior at or
posterior to the staple line. In some cases, surgeons prefer to have
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