Keywords
pancreatic cancer - pancreatectomy - postoperative complications - pancreatic fistula
- stricture
Introduction
Recent advances in the surgical techniques and postoperative intensive care have led
to a decrease in the mortality rates after major pancreatic procedures, now it ranges
from 1 to 3%. However, the morbidity rates are still high, resulting in longer hospital
stays and greater cost.[1]
[2] Imaging plays a fundamental role in the postoperative assessment. Specially, multidetector
computed tomography scans (MDCT) is the modality of choice in the postoperative settings.[1]
[3]
[4]
[5] Early diagnosis of the postoperative complications and differentiating them from
being normal or expected postoperative findings is crucial to offer the best possible
care for patients and to decrease the morbidity and mortality associated with surgery.[6]
[7]
In this article, we will briefly review the normal pancreatic anatomy, discuss the
main types of pancreatic surgeries, and illustrate the imaging findings during the
early postoperative period and of the main postsurgical complications in both acute
and chronic postoperative settings.
Normal Pancreatic Anatomy
Normal Pancreatic Anatomy
Pancreas is one of the largest digestive glands in the body. In adults, the gland
measures 12 to 15 cm in length and it has a tongue-shape with a soft to firm consistency
and lobulated surface.
It is divided into head, neck, body, and tail, thicker at its medial end (head) and
thinner toward the lateral end (tail) ([Fig. 1]). The head lies within the ‘C’ loop of the duodenum and the remainder of the gland
extends transversely and slightly cranially across the retroperitoneum (behind the
lesser peritoneal sac and the stomach). The neck is located to the left of the head,
immediately ventral to the portal vein (PV). The uncinate process is a triangular
prolongation of the caudal part of the pancreatic head behind the superior mesenteric
vessels[8]
[9] ([Figs. 1]and [2]).
Fig. 1 Illustration of the normal pancreatic anatomy. Pancreas is divided into head, neck,
body, and tail. The uncinate process is a triangular prolongation of the caudal part
of head behind the superior mesenteric vessels. Image courtesy: Kelly Kage, Media
Division, The University of Texas MD Anderson Cancer center.
Fig. 2 Illustration of the normal arterial supply to the pancreas. Image courtesy: Kelly
Kage, Media Division, The University of Texas MD Anderson Cancer center.
Arterial Supply
The pancreas has a complex arterial supply via branches from the celiac trunk and
superior mesenteric artery (SMA). The pancreatic head and adjacent duodenum are supplied
mainly by four arteries: two from the celiac trunk via the gastroduodenal artery (through
its anterior and posterior superior pancreaticoduodenal arteries/branches) and two
from the SMA via the inferior pancreaticoduodenal artery (through its anterior and
posterior inferior pancreaticoduodenal arteries/branches) ([Fig. 2]). Multiple branches from the splenic artery (including the dorsal pancreatic artery)
supply the remainder of the pancreas.[8]
[10]
Venous Drainage
Venous drainage of the pancreatic head occurs through the inferior pancreaticoduodenal
veins (anterior and posterior) which drain into the superior mesenteric vein (SMV),
and through the superior pancreaticoduodenal veins (anterior and posterior) which
drain into the PV (posterior) and the gastrocolic trunk (anterior). Venous drainage
of the body and tail of the pancreas is more variable but the common pattern is multiple
small branches draining into the splenic vein.[8]
[11]
Surgical Overview and Expected Postsurgical Appearances
Surgical Overview and Expected Postsurgical Appearances
Pancreatic surgery remains the only curative treatment for pancreatic cancer and plays
a key role in the management of medically intractable diseases, with most of these
procedures divided into resection or drainage.[12]
[13] In this review, we will focus on the resection procedures, mainly the different
kinds of pancreatectomy as follows.
-
Pancreaticoduodenectomy (PD) or (Whipple procedure)[14]: It is considered to be the standard procedure and the only curative option for
resection of head lesions (most commonly adenocarcinoma), and periampullary neoplasms.
This includes en bloc resection of the pancreatic head with uncinate process, duodenum
with distal stomach and proximal 20 cm of jejunum, distal common bile duct, and gall
bladder with regional lymphadenectomy. Its variation includes “pylorus preserving
pancreaticoduodenectomy.” After resection, the surgeon establishes three anastomoses
for reconstruction, namely, the pancreaticojejunostomy (PJ) or pancreaticogastrostomy
(PG), hepaticojejunostomy (HJ) or choledochojenostomy (CDJ), and gastrojejunostomy
(GJ) ([Fig. 3]).
Fig. 3 Diagrammatic illustration for Whipple procedure, showing the preoperative site of
a tumor in the head of pancreas (A), then the postoperative anatomical findings with the most common anastomotic sites;
pancreaticojejunostomy (PJ), gastrojejunostomy (GJ), and choledochojejunostomy (CJ)
(B). Postsurgical coronal contrast-enhanced CT (CECT) (C) following Whipple surgery in a 60-year-old female for the pancreatic head cancer
shows gastrojejunostomy (long arrow), pancreaticojejunostomy (short arrow), and choledochojejunostomy
(arrowhead), the three classic anastomoses performed as part of the Whipple surgery.
Postoperative anatomy after PD.[3] It usually varies according to the technique used, but we should mainly focus on
the three main anastomotic sites:
-
Pancreaticojejunostomy (PJ) or pancreaticogastrostomy (PG): The jejunal loop is most
often anastomosed to the right of the pancreatic remnant, anterior to the SMA, and
confluence of the SMV, PV, and SV.[15]
[16] It is seen as a short blind pouch of jejunum due to the usual end-to-side anastomosis.
This is important as it can often be misinterpreted as a fluid collection. Sometimes
collapsed loops of the bowel close to PJ can mimic tumor recurrence or hematoma.[4]
In cases with PG, the pancreas is anastomosed to posterior wall of proximal stomach
and can be seen as a defect on MDCT.[17] Surgeons’ preference is always the main factor for choice between those two techniques,
as the incidence of overall postoperative complications and the mortality rate are
not significantly different between them. However, a recent meta-analysis shows that
the incidence of postoperative pancreatic fistula is lower with PG than with PJ.[17]
[18]
-
Hepaticojejunostomy (HJ) or choledochojejunostomy: This one lies at a short distance
from the pancreaticojejunostomy (less than 5–10 cm distally), and is associated with
expected pneumobilia.[16]
[17]
-
Gastrojejunostomy (GJ): This anastomosis can be 30 to 40 cm distal with a segment
of the jejunum anastomosed to the stomach (antecolic), or it can be at a short distance
from the above two anastomoses. Exact position of this anastomosis may undoubtedly
vary depending on the institution and surgeon.[16]
[17]
-
Pylorus-preserving pancreaticoduodenectomy (PPPD), a variant of Whipple procedure
that retains the gastric antrum and the first part of duodenum and, anastomosing it
to the jejunum creating a duodenojejunostomy (DJ).[19]
-
Distal pancreatectomy (DP): It is performed for distal pancreatic cancers through
open procedure or by laparoscopy, depending on the location, size, and involvement
of the surroundings. En-bloc splenectomy is usually also done ([Fig. 4]) to allow complete resection and avoid local tumor recurrence.[6]
[20]
Fig. 4 Diagrammatic illustration for distal pancreatectomy (DP) procedure, showing the preoperative
site of a tumor in the tail of pancreas (A), then the postoperative anatomical findings with a splenectomy and a sealed off
pancreatic remnant with no anastomosis (B). Coronal postcontrast contrast-enhanced CT (CECT) images shows a circumscribed distal
pancreatic mass in a 19-year-old female (C) and postoperative anatomy following subsequent distal pancreatectomy and splenectomy
(D). This was proven to be solid pseudopapillary tumor (SPT) of pancreas. Residual unremarkable
pancreas (star) is sealed-off along the resection margin (arrow).
Normal postoperative anatomy following DP: Unlike the Whipple’s procedure, there is
usually only minimal disruption of the normal anatomy after DP because the surgeon
basically resects the distal pancreas and seals off the remnant with no anastomoses
between pancreas and bowel, unless rarely, a PJ to the distal pancreas is done for
chronic pancreatitis with proximal obstruction. Multiple studies demonstrate no significant
difference in the incidence of postoperative pancreatic fistula formation between
PD and DP procedures or between open and laparoscopic DP procedures.[21]
[22] Despite the less morbid or less extensive DP surgery compared with PD, some other
studies have observed that DP has a higher rate of some complications, especially
the pancreatic fistula (PF), abscess, and pseudocysts, which are the most common complications
of DP.[23] These are described in detail next.
-
Central pancreatectomy (CP): It has been proposed as an alternative to both PD and
DP for the removal of benign, traumatic and low malignant lesions in the neck or body
of the pancreas, to preserve the function of the remaining parenchyma.[6]
[24]
Normal postoperative anatomy following CP: Surgeons usually close the proximal stump
of the remnant pancreas with either a mechanical stapler or manual suture, similar
to DP. Then they anastomose the distal stump of the pancreas to the jejunum (PJ),
or attach it to the posterior wall of the stomach (GJ) similar to Whipple surgery.
Finally, this leads to a Roux-en-Y bowel at the level of the splenomesenteric venous
junction, which separates the head of the pancreas from the body and tail[25] ([Fig. 5]). CP has the advantage of preserving a large portion of normal parenchyma than compared
with the two previous surgeries and this may lead to a lower risk of diabetes, in
addition to a better residual exocrine function of the pancreas. On the other hand,
it has a higher risk of postoperative pancreatic fistula formation because of the
two different suture lines.[25]
[26]
[27]
Fig. 5 Diagrammatic illustration for central pancreatectomy (CP) procedure, showing the
preoperative site of the tumor in the pancreatic body (A), then the postoperative anatomical findings of central pancreatectomy with pancreaticojejunostomy
(B). Axial arterial phase postcontrast CT (C) in a 53-year-old woman performed following persistent abnormal abdominal sensations
shows small avidly enhancing mass (arrow) in the proximal pancreatic body. Central
pancreatectomy was done for its resection and this was proven to be pancreatic neuroendocrine
tumor. Coronal postcontrast CT image (D) shows expected postoperative anatomy with unremarkable pancreatic head (white arrowhead)
with adjacent surgical material (white arrow) to seal-off its medial end, and distal
pancreatic stump (black arrow head) anastomosed (black arrow) to adjacent jejunum.
-
Total pancreatectomy (TP): It is also known as a “double Whipple” and is reserved
for selected cases with pancreatic diseases involving the whole gland, such as familial
pancreatic cancer, metastases, and chronic intractable pancreatitis. The procedure
consists of removal of the entire pancreas, spleen, portions of the duodenum, common
bile duct, and the gallbladder.[28]
[29]
Normal postoperative anatomy following TP: It results in two anastomoses—one at the
biliary tree (hepaticojejunostomy) and the other at the remaining part of the duodenum
(duodenojejunostomy). This procedure leads to a complete pancreatic exocrine and endocrine
insufficiency. This also carries an extremely high postoperative morbidity and mortality
rates, especially if it is secondary to the postoperative complications of a previous
resection.[30]
[31]
Imaging Evaluation
Although plain radiographs are often performed for initial imaging evaluation in the
early postoperative settings after any abdominal surgery, and this is supplemented
with ultrasound following hepatopancreatobiliary surgeries, multidetector computed
tomography scans (MDCT) is the modality of choice to evaluate postoperative changes
and potential complications. Most patients undergo routine follow-up imaging one week
after surgery unless immediate complications are not suspected.[32] MDCT evaluations starts with unenhanced phase before contrast material injection
to help detect calcifications and hemorrhage. Then we start with an injection rate
of 3 to 4 mL/sec of 350 mg/mL iodinated contrast followed by 20 mL saline flush. We
study it during 3 phases: arterial phase (20–25 seconds post injection), pancreatic
phase (35–40 seconds), and late venous phase (delay of 70 seconds). The pancreatic
phase is crucial in the determination of vascular complications and for maximizing
enhancement difference between the tumor and the surrounding parenchyma, and the portal
venous phase helps characterize metastases to the liver during peak hepatic enhancement
in addition to fluid collections.[32]
[33]
[34]
[35]
MRI performance is similar to CT, but it may not be readily available and it requires
greater patient compliance. Hence, MRI with MRCP is mainly reserved to assess the
pancreaticobiliary ducts and anastomoses. MRI protocol includes multiplanar T1W and
T2W sequences with and without fat saturation, diffusion-weighted imaging, and three-dimensional
(3D) MRCP images. Hepatocyte specific contrast is administered for multiphasic postcontrast
imaging which includes late scan (often 20–30 minutes) in the biliary excretory phase
to evaluate the biliary ducts/leak.[35]
Imaging shows the normal postoperative anatomy with various anastomoses as discussed
earlier. Pneumobilia, perivascular soft tissue thickening or cuffing, fluid collections,
regional nodal enlargement, edematous swelling at the anastomoses, and peripancreatic
or mesenteric fat stranding are the usual expected postsurgical inflammatory changes.[35] By ~3 to 6 months, much of the inflammatory changes surrounding the surgical bed
usually get resolved, this includes resolution of some of the postoperative complications
such as seromas, ascites, abscesses, fat stranding, fistulas, and acute pancreatitis.[34] Despite the high recurrence risk and poor long-term survival rates, no evidence-based
guidelines exist for follow-up timing in cancer cases. Based on expert opinion, current
guidelines from the National Comprehensive Cancer Network (NCCN) and the European
Society of Medical Oncology (ESMO), recommend CT imaging every 3 to 6 months for 2
years, then once per year afterward.[36]
Postoperative Complications
Postoperative Complications
The most common postoperative complications following pancreatic surgery includes
ascites, seroma, abscess, anastomotic leak, hemorrhage, pancreatitis, pancreatic fistula,
delayed gastric emptying, portomesenteric venous thrombosis, and anstomotic strictures.
Postoperative complications may be categorized into early and delayed categories based
on the time after surgery ([Table 1]).
Table 1
Potential immediate and delayed complications of pancreatic surgery on imaging
|
Early
|
Delayed
|
|
Ascites
|
Anastomotic stricture
|
|
Seroma
|
Adhesions
|
|
Abscess
|
Pancreatitis
|
|
Anastomotic leak
|
Local tumor recurrence
|
|
Hemorrhage
|
|
|
Pancreatic fistula
|
|
|
Portomesenteric venous thrombosis
|
|
|
Pancreatitis
|
|
|
Delayed gastric emptying
|
|
|
Adhesions
|
|
|
Hepatic infarct
|
|
-
Seroma, ascites, and abscess: After Whipple procedure, around 100% of patients get
varying amounts of fluid collection in or around the surgical bed, along the surgical
tract, and in the abdominal wall and retroperitoneum. Radiological and clinical findings
together are the key to tell apart seroma from abscess, leakage, or hemorrhage.[4]
[37] Seromas present as simple fluid collections without enhancing rim which is often
seen with abscesses or complicated fluid collections ([Fig. 6]). The incidence of intra-abdominal abscess after PD surgery is around 6%.[37] Hemorrhage presents with high attenuating collections, and is described in detail
below.
-
Anastomotic leakage: Anastomotic leakage is seen in 4 to 10% of cases following PD.[38] On cross-sectional imaging, leakage may appear as fluid collections in or adjacent
to the surgical bed ([Fig. 7]), in perihepatic region, and may spread into the peritoneal cavity. If biliary leakage
is suspected clinically, a hepatobiliary iminodiacetic acid (HIDA) scan is one of
the best tools to detect approximate location and size of the leakage.[39]
-
Hemorrhage: Hemorrhage is suspected when the serum hemoglobin level falls below 8
mg/dL or when patient is hemodynamically unstable and/or need intravenous fluid administration
or blood transfusion.[40] Hemorrhage presents with high attenuating collections on CT. CT angiogram (CTA)
may be needed in these cases to locate the site of bleeding and to rule out postsurgical
arterial pseudoaneurysms. Tc-99m RBC scan may be needed to detect the intermittent
or minimum bleeding not detected on CT, as it is the most sensitive imaging modality
for detection of GI bleeding (0.1 mL/min threshold rate).[41] But on the other hand, surgical intervention should not be based on only a Tc-99m
RBC scan, because it has a poor anatomic localization of the bleeding site and it
cannot determine the pathological cause of bleeding.[41] Conventional angiography is an important tool in detecting as well as a therapeutic
modality for these pseudoaneurysms. Thus, it has an increasingly important role in
the diagnosis and management of acute gastrointestinal hemorrhage that is secondary
to pancreatitis or a pancreatic surgery, as the culprit leaking artery or pseudoaneurysm
may be embolized/coiled in the same sitting to stop the bleeding ([Fig. 8]).[42]
Fig. 6 (A, B) A 77-year-old woman who was status post Whipple surgery for pancreatic head cancer.
Patient presented with right flank pain and fever 2 weeks after surgery. Axial contrast-enhanced
CT (CECT) (A) showed rim enhancing fluid collection in the surgical bed suspicious for complicated
fluid collection. This was proven to be abscess following drainage catheter placement.
After 6 further weeks, patient presented with bloody drainage from this catheter.
Sagittal CECT (B) shows a subcentimeter saccular pseudoaneurysm involving the superior mesenteric
artery (long arrow) within the abscess cavity, which is seen as thick rim-enhancing
collection (arrowhead) with drainage catheter (short arrow) within.
Fig. 7 An 81-year-old man who was status post Whipple surgery for ampullary carcinoma with
increasing drain output. Axial contrast-enhanced CT (CECT) with intravenous and bowel
contrast, shows extraluminal bowel contrast in the surgical bed suspicious for the
leak (arrow) from the gastrojejunostomy or pancreaticojejunostomy site.
Fig. 8 An 83-year-old female with tachycardia and abdominal distention post Whipple surgery.
Axial arterial phase postcontrast CT image (A) shows active extravasation of contrast (arrow) with irregular hyperdense puddles
within the wall and lumen of the jejunum at the pancreaticojenostomy (PJ), with increasing
corresponding hyperdensity/contrast collection (arrow) on the venous postcontrast
phase CT (B). Conventional fluoroscopic celiac angiogram image (C) shows corresponding irregular active contrast extravasation due to bleeding (long
arrow) from a tiny branch (short arrow) of the splenic artery (black arrow). Bleeding
was stopped following immediate embolization.
Based on the time course, early postoperative hemorrhage occurs within first 24 hours
after surgery and often results from active bleeding of the poorly ligated or retracted
vessels, for example, from the gastroduodenal artery (GDA) stump. Bleeding typically
occurs into the peritoneal or retroperitoneal regions. Late postoperative hemorrhage
occurs mainly after 5 days and has a high association (up to 66%) with anastomotic
breakdown and sepsis; it is usually due to vascular erosion or pseudoaneurysm ([Figs. 6 and 8]) in the mesenteric vasculature.[43] This is usually managed with angiography and endovascular approach.[42]
-
Pancreatic fistula: Pancreatic fistula is the single most important cause of morbidity
and mortality after Whipple procedure. It occurs due to leakage of amylase rich secretions
at the PJ anastomosis site or from direct trauma to the pancreas.[44]
[45] In these cases, the surgical drain amylase levels are usually three times higher
than the serum levels on the third postoperative day, which is almost always diagnostic.[46] Although the drain output is the key to diagnosis, CT is very helpful in detecting
pancreatic fistulas ([Fig. 9]). Presence of a focal fluid collection or hemorrhage adjacent to the PJ is strongly
indicative, particularly if the collection is related to the pancreatic duct or anastomotic
suture line.[47] Development of a pancreatic fistula is also linked to other complications including
pancreatitis, abscess, and sepsis, with significant (20–40%) mortality.[44]
[46] Factors like gender (male), pancreatic duct–jejunum double-layer mucosa-to-mucosa
PJ anastomosis, pancreatic duct diameter ≤ 3 mm, degree of pancreatic fibrosis and
soft pancreatic parenchyma are associated with high risk of pancreatic fistula after
PD.[47] Presence of congenital pancreatic anomalies, for example, circumportal (annular
pancreas), can also lead to increased incidence of postoperative pancreatic fistula
and a special attention should be paid to look for pancreatic anomalies during surgery/pancreatectomy.
Preoperative imaging is also the key for its early identification. Finding of pancreatic
parenchyma encircling the PV/SMV suggests the presence of annual pancreas, and helps
alert the surgeon to anticipate the aberrant surgical field and be careful to avoid
the associated complications.[48]
Fig. 9 A 52-year-old man who was 20 days status post Whipple surgery for pancreatic head
cancer, underwent contrast-enhanced CT (CECT) for assessment of surgical bed fluid
collections. Persistent complicated rim-enhancing fluid collection (arrow) was seen
in the surgical bed with foci of gas related to catheterization. Drainage fluid was
positive for amylase, suspicious for pancreatic fistula. Patient required long-term
drainage catheter, and was treated conservatively with gradual improvement. Delayed
gastric emptying (not shown) also complicated postoperative course.
Management of pancreatic fistula consists of parenteral nutrition, empirical antibiotics,
percutaneous drainage, and octreotide. Unless severe anastomotic dehiscence is strongly
suspected, surgical repair is rarely attempted.[49]
-
PV thrombosis (PVT) and SMV thrombosis (SMVT): PVT/SMVT is rare, but serious complication
of Whipple procedure (incidence ~17%), and needs prompt diagnosis and aggressive management.[50] PVT/SMVT can be disastrous with risk of intestinal ischemia/necrosis with sepsis,
multiple organ dysfunction syndrome (MODS), and multiple organ failure (MOF), which
can be fatal.[51] The two most important risk factors are long operative times and use of prosthetic
grafts for reconstruction. Doppler ultrasound is used as first-line assessment in
acute clinical setting, showing lack of blood flow or venous waveforms in the corresponding
veins. On CT or MRI, perfusion abnormalities may be identified on the arterial phase
associated with filling defects on the portal venous phase. However, radiological
diagnosis may not be that obvious and sometimes missed, especially if the reader focuses
only on axial images. Coronal images ([Fig. 10]) are often important for accurate diagnosis and both veins should be carefully evaluated
in the coronal plane to search for short-segment filling defects that may be difficult
to visualize on the axial images.[52]
[53] Patients are treated with systemic anticoagulation, but surgical thrombectomy may
be an alternative in the acute setting.[50]
-
Postoperative pancreatitis: Because of the expected inflammatory changes and fat stranding
in the surgical bed after PD, diagnosis of mild postoperative pancreatitis is not
easy. Moreover, surgical manipulation can also elevate the levels of amylase and lipase
making it even difficult to confirm the diagnosis.[54] MDCT can detect severe cases as the peripancreatic inflammation, stranding, and
fluid is more evident in those cases. Severe postoperative pancreatitis is reported
in up to 30% of cases.[54]
-
Delayed gastric emptying: Incidence of delayed gastric emptying varies and may be
4 to 59% based on the criteria applied. Clinically, it is diagnosed based on the persistence
of nasogastric tube (NGT) after surgery, reinsertion of postoperative NGT, or delay
in starting regular diet.[55] In most cases, delayed gastric emptying is an indication of another underlying complication,
for example, abscess, fistula, and hemorrhage. Barium and nuclear medicine studies
can help confirm the diagnosis of delayed gastric emptying.[56]
-
Strictures: These are the most common delayed complications of PD, and mostly occur
at both the PJ or HJ anastomoses with incidence of 4.6% and 8.2%, respectively, at
5 years.[57]
[58] Patients of HJ strictures usually presents with jaundice and cholangitis, while
PJ strictures commonly manifests with abdominal pain, diarrhea, steatorrhea, pancreatic
insufficiency, and recurrent pancreatitis with pseudocysts on imaging[56]. Contrast enhanced–CT plays a vital role in diagnosing anastomotic strictures during
postoperative follow-up ([Fig. 11]), it should be suspected if there is change in the size of intrahepatic bile ducts
or the pancreatic duct, which warrants further evaluation.[59]
[60] MRCP has good specificity in the diagnosis of strictures, but it is not that sensitive.[59]
[60] Secretin induced MRCP is shown to detect the functional and subtle PJ anastomotic
strictures compared with EUS and ERCP with accurate detection of pancreatic duct and
anastomotic abnormalities while sparing patients the need for an invasive procedure.[61]
Fig. 10 A 40-year-old woman with status post portal vein stenting due to complication of
portal vein stenosis with postprandial pain following distal pancreatectomy for mucinous
cystic neoplasm. Coronal postcontrast CT 9 months after the stent placement, shows
occlusive thrombosis of the stented main portal vein (white arrow), associated with
multiple periportal and peripancreatic venous collaterals (black arrows).
Fig. 11 A 54-year-old man who was 1-year status post Whipple surgery for pancreatic head
cancer, underwent contrast-enhanced CT (CECT) for recurrent abdominal pain. CECT revealed
moderately dilated (arrows) pancreatic duct in the remnant pancreas suspicious for
stricture at the pancreaticojejunostomy. Patient required a redo pancreaticojejunostomy
for treatment.
Mechanical obstruction of the bowel loops by edema, early or late postoperative adhesions
and anastomotic narrowing/strictures, or, rarely, anastomotic ulceration may lead
to what is called “afferent loop syndrome/obstruction” (ALS). The afferent loop refers
to the duodenojejunal loop proximal to the gastrojejunal anastomosis.[62] Its obstruction presents with abdominal pain and vomiting. On imaging, it appears
as dilated fluid-filled tubular or C-shaped bowel (afferent limb/loop) in the right
upper quadrant or crossing the midline with transition in the region of anastomosis.
This often requires surgery to prevent further complications.[63]
[64] Nonanastomotic bowel obstruction can also result from adhesions or internal hernia,
as seen following other abdominal surgeries.
-
Hepatic infarction: Due to the fact that liver has dual blood supply (from HA and
PV), hepatic infarction is a very rare complication. It may occur because of the specific
vulnerability of patients exposed to the Whipple procedure, for example, long-term
clamp, HA injury or CA compression syndrome, HA thrombosis, or PVT. Other risk factors
include hypotension, sepsis, preexisting atherosclerotic disease, fibromuscular dysplasia,
or mesenteric vasculitis.[65]
[66] It is seen as peripheral wedge-shaped area of decreased enhancement in the liver.
Traversing vessels and lack of mass effect distinguishes this from a hepatic mass.[67]
-
Local tumor recurrence in the surgical bed: Most of the patients with disease recurrence,
usually present with distant metastatic disease, with only ~30% present with an isolated
surgical bed recurrence.[68]
[69] The median time of recurrence is around 20 months after initial treatment.[68] Presence of positive surgical margin is by far the most important risk factor for
recurrence.[69] MDCT is the modality of choice for diagnosis of local recurrent mass ([Fig. 12]) with an accuracy of 94%.[5] Correlation with elevated carbohydrate antigen (CA) 19–9 levels is useful in distinguishing
the recurrence from inflammatory stranding.[70]
Fig. 12 A 55-year-old man who was status post Whipple surgery for pancreatic head cancer
2 years ago, presented with crampy abdominal pain and steatorrhea, which did not respond
to pancreatic enzyme supplements. Contrast-enhanced CT (CECT) revealed a heterogeneously
enhancing mass (arrow) in the mesenteric root encasing the superior mesenteric artery
suspicious for recurrent malignancy. This was proven on biopsy.
Conclusion
Surgical intervention remains the main treatment option for both the neoplastic and
intractable inflammatory pancreatic diseases, despite the development of various medical
and minimally invasive treatment approaches for pancreatic disease. Radiologists are
required to be familiar with the normal or expected postoperative imaging findings
following different types of pancreatic surgeries, to timely detect the postoperative
complications or tumor recurrence.
