This presentation is on surgical anatomy of pancreas and anatomy oriented explanations of different surgeries of pancreas

1. Resectional Anatomy of Pancreas
Dr Happy D Kagathara
4th
January, 2015
CME – Management of Pancreatic Neoplasms
Ahmedabad Surgeon’s Association

2. Outline
• Gross anatomy
– Gland
– Vascular anatomy
– Lymphatic drainage
– Ductal anatomy
• Approach for resection
– Pancreatico-duodenectomy
– Distal pancreatectomy

3. Introduction
• Pancreatic surgery
– Complicated and technically challenging
– Requirement of detailed understanding of anatomy and relation to
adjacent structures
• Casual observer assumed that pancreas played an insignificant role
– First discovery
• By Herophilus
• Referred to as the “finger of the liver”, between 200 BC and 200
AD
– 400 years later, Ruphos, gave the name “pancreas” (“all flesh” In
Greek)
– Grey’s Anatomy (1901 edition) – “Pancreas presents but little of
surgical importance
– Whipple, surgery for pancreatic neoplasm in 1930

4. Gross anatomy
• Soft, elongated, flattened
• Length – 4 to 6 inches
• Weight – 92 gm (41 to 182 gm)
• Oblique location
– Epigastric & left hypochondriac regions
– T12/L-1 to L-3
• No true capsule, covering of fine connective tissue
• Arbitrary division

5. Gross anatomy: Head
Lies within the C-shaped concavity of the duodenum
2 surfaces: anterior and posterior
The anterior surface is
adjacent to the pylorus, the first part of the
duodenum, and the transverse colon and crossed by the
attachment of the root of the transverse mesocolon.
The posterior surface
abuts the right kidney, the inferior vena cava and
the right renal vessels, and the right crus of the
diaphragm.

6. Gross anatomy: Uncinate Process
• Projection from the lower part of the head
• Extending upward and to the left
• Lies posterior to SMA and SMV
• Lies anterior to aorta and the inferior vena cava
• Variable size
• SMA give branches into and SMV receive tributaries from the uncinate
process

7. Gross anatomy: Neck
Constricted part
1.5 to 2.0 cm long and 3.0 to 4.0 cm wide
From the head toward the left
Extends to the right as far as the ASPDA
Anterior surface
Lesser sac cavity
Pyloro-duodenal junction
Gastroduodenal artery
Posterior surface
confluence of the SMV and SV, forming PV
The IMV is related to the inferior border and may pass
behind it to enter the SV or turn medially to enter the
SMV

8. Gross anatomy: Body
Prismoid shape
Runs toward the left side
Anterior surface abuts
The antrum and body of the stomach and the
transverse mesocolon
Superior border related to
Coeliac trunk (runs forwards above)
Splenic artery (runs to the left along this border)
Anterior border gives attachment to the transverse
mesocolon.
Posteriorly related to
The aorta, origin of the SMA, the left crus of the
diaphragm, the left kidney and its vessels, the left adrenal
gland, and the SV
Inferior surface
Covered by peritoneum of the greater sac
Duodenum-jejunal flexure
Coils of the jejunum
Left colic flexure
The middle part of the body overlies the lumbar spine,
which makes this area of the pancreas most vulnerable
to abdominal trauma

9. Gross anatomy: Tail
Relatively mobile, tapering end
Abuts hilus of spleen
Rests on splenic flexure
lies in the lineorenal ligament accompanied by the splenic
vessels and lymphatics

10. Gross anatomy: Peritoneal Covering
• *Posterior 2 layers of the greater omentum diverge
on the anterior surface of the head and the body
– Anterior layer passes upwards and covers the
anterior surface
– Posterior layer passes downwards and covers
the inferior surface
• End of the tail within lienorenal ligament
• Posterior surface is devoid of peritoneum
Vascular relations to IVC, left renal vein, aorta, celiac axis and
branches, SMA, PV, SMV, SV make the pancreas prone for
invasion by malignant pancreatic disease

11. Arterial circulation
• *The head and uncinate process
– Supplied by the pancreatico-duodenal arcade
• On the anterior and posterior surface of the pancreas next to the
duodenum
• Anterior arcade – closer to the duodenum
• From the SPDA (branch of GDA) and IPDA (branch of the SMA)
• The second system from the SA
– gives three arteries on the dorsal surface of the gland
– The dorsal pancreatic artery
• Most medially
• Right branch supplies the head and usually joins the posterior
arcade in the neck
• one or two left branches make connections with branches of the
SA and the left gastroepiploic artery
• In 1/3rd
cases, tail of pancreas receives supply from left gastro-epiploic
artery
Two arterial system
For head and uncinate process
For body and tail
The neck is a watershed between these two

12. Arterial circulation
The coeliac artery
Rises vertically, close to the superior edge of the pancreas
Gives off the CHA-GDA and the SA
The splenic artery
Run posterior to the body and tail
The SMA
Rises posterior to the junction of the neck and body

13. Arterial circulation
• Inferior pancreatic artery*
– 22% - absent IPA
– 25% - body and tail supplied only by branches of IPA, increases risk of
pancreatic infarction if IPA thrombosed.
• Inferior pancreaticoduodenal artery*
Continuation of dorsal pancreatic artery, within the pancreas,
towards inferior margin
Landmark for pancreatic head resection
Ligation of IPDA opens up plane for dissection for SMA,
posterio-medial margin of resection

14. Venous drainage
• *The veins of the body and tail of the pancreas
– Short and fragile
– Drain into the SV
• The veins of head and uncinate process
– The pancreaticoduodenal veins lie close to their corresponding
arteries
– Drain into the SMV and PV
– Invariable tributary entering the PV at the level of superior margin of
head
• The veins from Uncinate process
– Drain into a large first jejunal vein,
• abuts the uncinate process
– Empty into the SMV
Follows arterial supply

15. Venous drainage
• Splenic vein*
– Because of the close anatomic relationship, inflammatory or
neoplastic diseases involving the body and tail can lead to SV
occlusion resulting in retrograde venous drainage toward the splenic
hilum and then, through the short gastric veins, can create gastric
varicesOriginates at the hilum of the
spleen and run to the right along
the posterior surface of the
pancreas, partly embedded in the
back of the pancreas

16. Venous drainage
• Inferior mesenteric vein
– Normally not drain the pancreas*
– If the termination of the SV is surgically occluded during a resection,
IMV may become a draining vein of the pancreas
• Only when it drains into the SV
Related to the inferior border of the neck and may pass behind
it to enter the SV or turn medially to enter the SMV or into the
confluence

17. Lymphatic drainage
• *Standard node dissection during Whipple’s procedure
– Removes all N1 nodes unless there is direct lymphatic drainage to the
left side of the SMA or to nodes around the coeliac artery
• Anterior and posterior lymphatic system
– Run near the pancreaticoduodenal vessels.
– Each drainage system has superior and inferior sub-systems
Understanding of drainage is important for accurately staging the
disease and for achieving clearance to reduce risk of loco-regional
recurrence
Ring of nodes around the pancreas that drain the adjacent sections of
the gland (N1).
These nodes drain into nodes along the SMA, coeliac artery and aorta
(N2, axial nodes).
Axial nodes are also N1 for portions of the head, body and
uncinate process that lie close to the aorta

18. Lymphatic drainage
• Head of the pancreas and duodenum
– Upper head drains into subpyloric nodes
– Inferiorly drains into retropancreatic and antepancreatic nodes
– Into the celiac and superior mesenteric groups of pancreatic nodes
and into the cisterna chyli
• Body of pancreas
– Drain into the pancreaticosplenic nodes
• Lying along the superior border
• Drain into celiac nodes
• Tail of the pancreas
– drain into splenic hilar nodes

19. Ductal anatomy: PD
• The main pancreatic duct (of Wirsung)*
– 3.1 - 4.8 mm in the head, tapers to 0.9 - 2.4 mm in the tail
• The uncinate process is served by its own duct
– joins the main pancreatic duct 1–2 cm from its entry into the
duodenum.
Begins near the tail of the pancreas, courses left to right
Formed from anastomosing ductules draining the lobules of
the gland

20. Ductal anatomy: PD
• The accessory pancreatic duct (of Santorini)
– Present in 70%*
– Drains into the minor papilla
• 2cm proximal to the ampulla of Vater in the second duodenum
Runs upwards
Receives ductules from the lower part of the head
Usually communicates with the main duct

21. Ductal anatomy: PD
– No connection between the accessory duct and the main duct in 10%,
Pancreatic divisum
– Only duct of Santorini in 2%

22. Ductal anatomy: Intrapancreatic CBD
• As CBD descends behind 1st
part of duodenum, it becomes enclosed by
(80%) or grooves (20%) the pancreas as it passes to exit at papilla.
Each duct and the common channel have their own sphincters

23. Ductal anatomy: Sphincter mechanism
– PD Joins CBD within the sphincter segment in 70% - 85%*
• In sphincteroplasty, open the common channel superiorly (10–12 o’clock
position in the mobilised duodenum) to avoid the orifice of the pancreatic
duct (4 o’clock)
– PD Enters the duodenum independently in 10% - 13%
• Pancreatic duct more inferiorly
The length of the common channel 4.5 mm (1 to 12
mm)

24. Innervation
• Splanchnic nerve – sympathetic innervation
• Vagus nerve – parasympathatic innervation
• Both has efferent vasomotor fibers to the pancreatic acini, ducts and
blood vessels and afferent pain fiber
• Afferent pain fibers pass through the celiac plexus to cell bodies in dorsal
root ganglia within the splanchnic nerves

25. Innervation
• Sympathetic efferent fibers
– Pre-ganglionic fibers run through greater (T5-T10), lesser (T9-T11) and
least splanchnic nerves
– To celiac and SMA ganglia
– Post ganglionic nerve fibers reach pancreas by accompanying
branches of arteries
• Parasympathetic efferent fibers
– Pre-ganglionic nerves from celiac division of the posterior vagal trunk
– ganglia within pancreas
– Postganglionic fibers terminates at pancreatic islet cells

26. Approach to pancreas (PD)
• Right subcostal incision with Midline extension
• Entering the lesser sac
– Approach
• Divide of the greater omentum below the gastroepiploic arcade,
or
• Release of the greater omentum from its attachment to the
transverse colon
– The anterior surface of the neck, body and tail are often visible but
may be obscured by congenital flimsy adhesions to the posterior wall
of the stomach

27. Approach to pancreas (PD)
• Exposure of head
– Mobilization of the right side of the transverse colon and hepatic
flexure inferiorly
– Kocher maneuver (2nd
part of duodenum)

28. Approach to pancreas (PD)
• Exposure of the neck
– Division of the right gastroepiploic vein*
– Division of anterior branch of IPDV at inferior border of body
– Normally no veins enter the SMV or PV from the posterior surface of
the neck of the pancreas*
Crosses the inferior border of the pancreas to join with
the middle colic vein to form the gastrocolic trunk, which then enters
the SMV.
Most common site for venous bleeding in pancreatic
surgery
Neck can be separated from the anterior surface of the
SMV/PV in this avascular plane

29. Approach to pancreas (PD)
• Celiac axis stenosis
– Important vascular consideration in pancreatic head resection
– Liver more reliant on supply via GDA or anomalous HA
– Temporarily occlude GDA before division to test that HA pulsation in
the porta is not lost*
• Right gastric artery division and ligation
GDA or IPDA stumps are common sites for arterial bleeding in
pancreatic surgery

30. Approach to pancreas (PD)
• Division of First two- three jejunal veins
• Uncinate process dissection from above to below
– The veins from Uncinate process divided
• A soft pancreas + MPD with normal diameter
– high risk for P-J anastomotic leakage
• Relatively high output of pancreatic juice

31. Approach to pancreas (DP)
• Exposure of body and tail
– Splenic flexure mobilisation to expose lower pole of spleen, hilum and
pancreatic tail
– Peritoneal incision along inferior border of body the pancreas

32. Access to pancreas (DP)
– Infereior mesenteric vein ligation (Try to preserve)
– Division of splenic vessels along superior border of pancreas

33. Take home message
• Retroperitoneal organ divided into Head, uncinate process, neck, body,
tail
• Detailed knowledge of anatomy and relation to surrounding visceral
structures are important for better oncological outcome in pancreatic
cancer surgery
• Understanding of lymphatic drainage is Important
– For accurately staging
– For achieving clearance to reduce risk of loco-regional recurrence

34. Take home message
• Arterial supply
– Head and uncinate process
• Supplied by the pancreatico-duodenal arcade
– Body and tail
• The second system arises from the splenic artery
• Venous drainage
– Head and uncinate process
• The pancreaticoduodenal veins lie close to their corresponding
arteries
• Drain into the superior mesenteric vein (SMV) and portal vein (PV)
– Body and tail of the pancreas
• Drain into the splenic vein