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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_734_Библиотеки_им_академика_М_И_Перельмана.pdf
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D. Asbun et al.
fourth portion of the duodenum, for infra-ampullary lesions. Both PSDs and DSDs
preserve part of the duodenum and are inherently pancreas-preserving, meaning
they do not involve pancreatic resection. Instead, the pancreatoduodenal complex is
separated and a segment of duodenum resected in isolation. A similar approach has
been described by the authors to perform total duodenectomy with reimplantation
of the biliopancreatic duct complex [10]. However, this chapter will focus on PSD
and DSD, in which the ampulla is not resected.
Anatomy
The duodenum is approximately 25–30cm long and in direct continuity with the
pylorus, marking the start of the small intestine. It continues from the pylorus laterally and then inferiorly in a “C” shape along the lateral edge of the head of the
pancreas, before turning medially. It is suspended upwards at the root of the mesentery by the suspensory muscle of the duodenum, or Ligament of Treitz, which marks
the duodenojejunal exure and thus the transition from duodenum to jejunum. This
“ligament” is a band of brous and sometimes muscular bers arising from the right
crus of the diaphragm. After this point, the jejunum continues caudad through the
base of the transverse mesocolon into the infracolic abdomen.
The rst portion of the duodenum (D1) is approximately 2–4 cm long and is
generally not adhered to the head of the pancreas. D1 receives blood supply from
the supraduodenal and gastroduodenal arteries. The proximal portion of D1 can be
enlarged and is often called the duodenal “bulb.” As the second portion of the duodenum (D2) begins its C-loop curve around the head of the pancreas, it transitions
from intraperitoneal to retroperitoneal, and is attached to the pancreas. D2 is perfused by perforating arteries from the head of the pancreas. It is roughly midway
along D2 that the pancreatic and biliary ducts typically join at the ampulla of Vater
to insert into the duodenum, via the major duodenal papilla. In some patients, the
accessory pancreatic duct of Santorini empties into the minor papilla proximal and
somewhat anterior to the major papilla.
The third portion (D3) continues to the left after the C-loop, passing anterior to
the vena cava and aorta and with blood supply from the uncinate process. D3 simultaneously passes posterior to the root of the bowel mesentery, which envelopes the
superior mesenteric artery (SMA) and vein (SMV). The fourth portion (D4) continues to the duodenojejunal exure, often behind other sizable mesenteric blood vessels, receiving perfusion from branches off the superior mesenteric artery. There are
folds of parietal peritoneum reecting off D4 which form the paraduodenal fossa.
D1, D2, D3, and D4 are also referred to as the superior, descending, transverse, and
ascending portions of the duodenum, respectively, which summarizes their courses.
D2, D3, and D4 are retroperitoneal, and as such their mobilization requires incision of overlying peritoneum. There are multiple layers of connective tissue that
surround the duodenum and pancreatic head, which are remnants of embryologic
structures. Most anteriorly is the parietal peritoneum, and as dissection proceeds
14 Segmental Duodenectomy
Fig. 14.1 Embryologic origins of periduodenal connective tissue. Far left image shows earliest
structure origins, far right image shows fully developed anatomy [12]
233
deeper along the lateral edge of the duodenum, the so-called fusion fascia of Treitz
is encountered [11–13]. The fusion fascia of Treitz is a fusion of multiple layers of
connective tissue membrane that cover the ventral and dorsal mesenteric buds during embryologic development. These membranes also overlie the inferior vena cava
and aorta (Fig.14.1). During medial mobilization of D2 and D3 (Kocher maneuver), this fascia remains adherent to the pancreatoduodenal complex and not to the
vena cava or aorta. The SMA pierces through this fascia after takeoff from the aorta
(Fig.14.2).
There is also a connective tissue plane between the head of the pancreas, D2/D3,
and the bile duct (Fig.14.3). This “groove” is the location of groove pancreatitis, an
uncommon clinical entity characterized by pancreatitis that extends primarily into
this potential space [15, 16]. This plane is critical to identify and follow during segmental duodenectomy.
Preoperative Preparation andPearls
Many duodenal lesions are asymptomatic, especially those not involving the
ampulla. Most common symptoms attributable to duodenal lesions include crampy
abdominal pain and gastric outlet obstruction. Signs of biliary obstruction such as
jaundice should raise concerns for an ampullary neoplasm. Some lesions may present as obvious or occult gastrointestinal bleeding, most characteristically gastrointestinal stromal tumors or adenocarcinomas with associated mucosal ulceration.
Cross-sectional abdominal imaging is important to evaluate for signs of locoregional or distant spread, with specic workup depending on the type of neoplasm
diagnosed. It is important for computed tomography (CT) or magnetic resonance
imaging (MRI) to have appropriate contrast phases and thin radiographic cuts at the
level of the duodenum, which is usually a part of pancreatic imaging protocols. This
is important to better assess the relationship of the lesion to the neighboring
234
Fig. 14.2 Sagittal view of
third portion of duodenum
and its relation to
mesenteric vessels and
surrounding structures.
Fusion fascia of Treitz
represented by dotted red
line [12]. MCA middle
colic artery, SMA superior
mesenteric artery
D. Asbun et al.
Fig. 14.3 Relations between different structures of the pancreatoduodenal complex.
Pancreatoduodenal groove outlined in red on the left [14]
pancreatic parenchyma. MRIs should include diffusion-weighted phases. Oral contrast can be helpful, especially when evaluating the cause of an intestinal obstruction, but is not as important as properly timed intravenous contrast. Oral contrast
can be given as part of a CT or MRI, or as a separate upper gastrointestinal X-ray
series, although these series are of less utility once the diagnosis of a duodenal
lesion is made.
14 Segmental Duodenectomy
Fig. 14.4 Endoscopic
appearance of a duodenal
mass. Major papilla
labeled at top. With
permission from HJ Asbun
235
The majority of duodenal lesions should be worked up with an esophagogastroduodenoscopy (EGD) and biopsy by a skilled endoscopist (Fig.14.4). Additionally,
endoscopic ultrasound (EUS) can provide important information regarding the duodenal lesion’s depth of invasion, the appearance of periduodenal lymphadenopathy,
and the presence of other suspicious masses in the area (Fig.14.5). Tissue diagnosis
is most commonly made from tissue biopsy during EGD.
Endoscopic submucosal tattooing of the lesion is an important part of preoperative workup [17]. For this reason, it is important for the endoscopist and the surgeon
to be in regular communication, ideally before endoscopy for a suspected duodenal
malignancy. At time of EGD, a tattoo is placed proximal and distal to the lesion.
These two tattoos, visible from inside the peritoneum during surgery, guide the lines
of transection across the duodenum. It is thus important for the endoscopist to take
care to accurately place the tattoos adjacent to where the lesion starts and ends, but
not on the lesion or its edges. Ideally, only a small amount of dye is injected. Overinjection of dye can have excessive submucosal spread, making it harder to identify
the specic location being tattooed.
As with other neoplasms, multidisciplinary discussion is imperative, preferably
during multidisciplinary tumor board conferences. The management of duodenal
neoplasms can be complex and may involve chemotherapy or other treatment
modalities depending on the diagnosis [18, 19].
236
Fig. 14.5 Endoscopic
ultrasound of the
duodenum showing a mass
(circled in white). With
permission from HJ Asbun
Fig. 14.6 Port placement
for segmental
duodenectomy. With
permission from D Asbun
D. Asbun et al.
Laparoscopic Segmental Duodenectomy
Patient Positioning andPort Placement
The patient is positioned supine with legs split and arms tucked. Ports are placed as
shown in Fig.14.6, with a total of two 5mm and three 12mm ports. The subxiphoid
5mm port is solely for the surgical assistant. The other ports are positioned to allow
14 Segmental Duodenectomy
237
for triangulation towards the duodenum with adjustment of surgical instruments and
camera depending on what portion of the duodenum is being dissected. Patient positioning and port placement is the same for both PSD and DSD.
Technique: Laparoscopic Proximal Segmental Duodenectomy
(Figs14.7 and14.8)
Key Steps:
– Enter lesser sac, mobilize colon, expose duodenum (Video 14.1)
– Transect proximal duodenum with pyloric preservation (Video 14.2) (or gastric
antrum if pylorus included in resection)
– Limited Kocher maneuver, mobilize proximal duodenum (Video 14.2)
– Dissect within pancreatoduodenal groove (Video 14.3)
– Conrm location of ampulla with IOC (Video 14.4)
– Transect duodenum distally (Video 14.4)
– Duodenojejunostomy (or gastrojejunostomy) (Video 14.5)
– Cholecystectomy
After insufation and port placement, the gastrocolic ligament is incised and the
lesser sac is entered. Dissection proceeds to the right, preserving the gastroepiploic
arcade, until the greater omentum is separated from the distal stomach and pylorus.
Any adhesions from the omentum to the hepatoduodenal ligament or gallbladder
are taken down. The parietal peritoneum lateral to the duodenum is incised and the
avascular plane between the transverse mesocolon and retroperitoneum is entered.
Dissection along this plane mobilizes the transverse mesocolon inferiorly away
Fig. 14.7 Proximal
segmental duodenectomy
with pylorus preservation.
Gray area represents
segment resected. With
permission from D Asbun
238
Fig. 14.8 Proximal
segmental duodenectomy
with resection of pylorus
and distal stomach. Gray
area represents segment
resected. With permission
from D Asbun
D. Asbun et al.
from the duodenum. It can be followed laterally to take down the hepatic exure and
upper ascending colon as needed for adequate exposure of the duodenum.
Adhesions to the posterior aspect of the stomach and pylorus are taken down
with a surgical energy device. The gastroepiploic pedicle containing the gastroepiploic vein and artery is identied, isolated, and divided en bloc using a surgical
stapler with a vascular load. Skeletonization of the vessels is not necessary.
Alternatively, clips can be used. Dissection proceeds distally, mobilizing the proximal duodenum until arriving at the junction between duodenum and pancreas. Care
is taken to avoid inadvertently incising the pancreatic capsule or serosa of the duodenum. The superior edge of the pylorus and duodenum are also mobilized by incising the pars accida of the gastrohepatic ligament near the pylorus. The course of
the gastric arteries along the lesser curve is preserved although the right gastric
artery may need to be sacriced if it reaches the lesser curve too far distally.
The duodenum is divided approximately 2–3cm distal to the pylorus as long as
an adequate margin can be assured proximal to the tattoo (Fig.14.7). Nasogastric
tubes are withdrawn prior to duodenal transection, and perfusion to the proximally
divided duodenum is assessed. If the duodenal lesion is too close to the pylorus to
allow for transection 2–3cm beyond the pylorus, the pylorus is sacriced and the
gastric antrum is transected (Fig.14.8).
A Kocher maneuver is performed to medialize the proximal duodenum. This
maneuver is carried out to the extent that allows adequate exposure of the duodenal
segment to be resected, and a full Kocher maneuver is often not necessary. The
duodenum is reected medially and the peritoneum adjacent to the duodenum is
incised. Dissection continues posteriorly along the avascular plane between the
duodenum and the retroperitoneum, while progressive medial traction is applied.
Once the segment of duodenum marked with the distal tattoo is free from the retroperitoneum, it is not necessary to further medialize the more distal duodenum.
14 Segmental Duodenectomy
239
Strong anterolateral traction is applied to the duodenum. This tension helps
expose the plane between the pancreas and the duodenum, entering the pancreatoduodenal groove. Takedown of the anterior connective tissue layer leads the dissection along this connective tissue plane, exposing the brovascular attachments
between the pancreas and duodenum (Fig. 14.9). Dissection proceeds carefully
from proximal to distal, and the duodenum is gradually separated from the pancreatic head. The authors prefer ultrasonic shears during this dissection. Taking very
small bites with the use of a hemostatic energy device is essential to control the
perforating vessels that traverse this between the pancreas and the duodenum.
Dissection is precise to avoid deviation beyond the plane and into the pancreas or
duodenum.
The extent of dissection is determined by the location of the distal tattoo and the
calculated location of the ampulla. It must proceed beyond the distal tattoo, but
without crossing into the periampullary region. As dissection nears the periampullary region, there is often an increase in perforating vessels, signaling the vicinity of
the common bile duct.
Once sufcient dissection is achieved, the hepatocystic triangle is dissected to
expose the cystic duct, which is clipped and cannulated distally with a cholangiogram catheter. A bowel clamp is then placed across the duodenum at the planned
distal transection margin. An IOC is performed with the clamp in place to conrm
that the ampulla is not occluded by the bowel clamp. The clamp is replaced by a
laparoscopic surgical stapler, assuring the wider stapler is not placed beyond the
distal edge of the bowel clamp. The IOC can be repeated with the stapler in place if
the surgeon has doubts about the patency of the ampulla (Fig.14.10). The distal
duodenum is stapled and transected.
The specimen is placed in an endoscopic retrieval bag, oriented so as to present
one of the stapled edges rst. It can usually be extracted by enlarging one of the
12 mm port sites an extra 2–4 cm. If the specimen is larger, it can be extracted
through a Pfannenstiel incision. The peritoneum at the extraction site is reapproximated afterwards to allow for re-insufation, with trocar usually replaced through it.
Fig. 14.9 View of
pancreatoduodenal groove
during dissection of a
proximal duodenal lesion.
D duodenum, P pancreas,
Red arrow
pancreatoduodenal groove.
With permission from HJ
Asbun
240
Fig. 14.10 Intraoperative
cholangiogram with a
surgical stapler clamped
across planned duodenal
transection line during a
proximal segmental
duodenectomy. Contrast
ows freely through the
patent ampulla into the
duodenum. With
permission from HJ Asbun
D. Asbun et al.
If the pylorus was preserved, a loop of jejunum approximately 30–40cm distal
to the ligament of Treitz is positioned antecolic, and an end-to-side duodenojejunostomy is performed. The pylorus is gently dilated prior to anastomosis. The authors
perform a two-layer duodenojejunostomy using absorbable barbed suture for both
layers. Small but full-thickness bites are important, including the staple line in the
posterior suture line. If the pylorus was sacriced, a stapled gastrojejunostomy is
performed, either in a Roux-en-Y fashion, or Billroth II fashion. A Braun jejunojejunostomy may be added to the Billroth II to decrease the chance of excessive bile
reux into the stomach.
A cholecystectomy is completed following dissection in the hepatocystic triangle
started with the IOC.The duodenojejunal (or gastrojejunal) anastomosis is inspected
for proper perfusion and closure. Fluorescent angiography can aid in assuring
proper perfusion to the anastomosis, and an air leak test can also be performed to
further assure anastomotic integrity.
Technique: Laparoscopic Distal Segmental Duodenectomy
(Fig.14.11)
Key Steps:
– Enter lesser sac, mobilize colon, expose duodenum (Video 14.1)
– Wide Kocher maneuver, takedown ligament of Treitz (Video 14.6)
– Pull jejunum into right upper quadrant, transect jejunum (Video 14.7)
14 Segmental Duodenectomy
Fig. 14.11 Distal
segmental duodenectomy.
Gray area represents
segment resected. With
permission from D Asbun
– Dissect within pancreatoduodenal groove (Video 14.8)
– Conrm location of ampulla with IOC (Video 14.9)
– Transect proximal duodenum (Video 14.9)
– Duodenojejunostomy (Video 14.10)
– Cholecystectomy
241
The lesser sac is entered and the colon mobilized using the same method as for
PSD.However, for DSD a full Kocher maneuver is generally performed, with medialization of the duodenum such that the inferior vena cava and insertion of the left
renal vein is exposed. Dissection continues distally along an avascular plane
between the duodenum and the transverse mesocolon. In this plane, there are adhesions to the antimesenteric side of the duodenum, which is followed close to the
duodenum. Deviation away from these antimesenteric adhesions risks injury to duodenal or colonic mesentery. Eventually the duodenojejunal exure is reached and
the ligament of Treitz is taken down from right to left. Both the proximal and distal
tattoos should have been identied.
At this point, D4 should be free from its attachments and the duodenojejunal
exure taken down. The proximal jejunum is pulled up into the right upper quadrant. This jejunum is transected beyond the distal tattoo on the duodenum using a
surgical stapler. The small bowel mesentery proximal to the staple line is cut with a
surgical energy device adjacent to the proximal jejunum/distal duodenum. This continues until the duodenum is found to join with the pancreatic head.
The duodenum is pulled anterolaterally to expose the pancreatoduodenal groove,
and the connective tissue plane is entered with ultrasonic shears (Fig. 14.12).
Dissection along this plane is performed as described for PSD but from distal to
proximal. It is continued proximally until just past the proximal tattoo, but without
entering the periampullary area. Careful use of an energy device is important, as
perforating vessels from the pancreas to the duodenum will be encountered and