Surgical Conditions of the Spleen, Liver, and Extrahepatic Biliary System Flashcards
What is the most common malignancy in the spleen?
- Hemangiosarcoma
What are other splenic malignancies besides hemangiosarcoma?
- leiomyosarcoma, osteosarcoma, fibrosarcoma, undifferentiated sarcoma, lymphosarcoma, plasma cell tumor, mast cell tumor
What are three common benign masses in the spleen?
- Hemangioma
- Nodular hyperplasia
- Hematoma
Can you tell the difference between the most common malignant splenic mass and the common benign splenic masses via gross appearance or cytology (i.e. without histopathology)?
You cannot
Odds that a splenic mass is benign or malignant if found incidentally or was a mass that has not bled
- 30% malignant
- 70% benign
Odds that a splenic mass is malignant if ruptured and caused a hemoabdomen?
- 2/3 are malignant
- 1/3 are benign
Dfdx for liver nodules
- Mets from splenic neoplasia
- Extramedullary hematopoiesis
- Nodular hyperplasia
- Primary liver neoplasia
Can you tell apart grossly whether a splenic mass is benign or malignant?
- You cannot
Can you differentiate on cytology splenic HSA, hemangioma, and hematoma?
- You cannot
Which breed has an increased incidence of HSA?
- German SHepherds
- More common in large than small breed dogs
Most common primary sites for HSA
- Spleen
- Right atrium and auricle
Metastatic rate for HSA
- High
Where does HSA met?
- Liver, omentum, and lung
Thus, a pre-op plan for patient with potential splenic HSA should include what diagnostics?
- Advise echocardiogram
- Thoracic radiographs
- Abdominal ultrasound
Survival time for splenic mass if benign
- Surgery is curative
Survival time for HSA mass with splenectomy alone and with chemotherapy
- 1-3 months with splenectomy alone
- 3-12 months with splenectomy and chemotherapy
What should you do when you diagnose a splenic mass but don’t yet know what kind it is an need to advise the owners?
- Advise that while malignant splenic masses like hemangiosarcoma have a poor prognosis, some other splenic masses can be cured via splenectomy
If you see hepatic nodules in a dog with a splenic mass (or any other mass), does that mean that metastasis has for sure occurred?
- NO
How can splenic torsion occur?
- The spleen can rotate around its vascular pedicle, obstructing venous drainage, leading to splenomegaly, congestion, and possible thrombosis, strangulation, necrosis, or sepsis
How does splenic torsion occur most commonly?
- In large, deep chested dogs and while it is often associated with GDV, it can occur isolated
Is a splenic torsion an emergency?
- YES
Should you untwist the spleen prior to removal?
- DO NOT to avoid reperfusion
Indications for splenectomy
- COnfirmed splenic neoplasia
- Splenic mass for which neoplasia is a main ddx
- Splenic mass (benign or malignant) that has bled significantly or is at risk of bleeding (treat hemoabdomen medically until patient is stabilized if possible)
- Splenic torsion
- Severe trauma to spleen with uncontrolled bleeding or necrosis (most traumatic bleeds from spleen can be managed medically)
- +/- immune mediated disease
Consequences of spleen removal in dogs
- Lack of spleen is tolerated very well in dogs with minimal consequences
Ligations - what direction for splenectomy?
- Usually from tail to head of spleen
- Splenic artery
- Then left gastroepiploic artery
- then short gastric artery
Ligation options for splenectomy
- Suture, clips, and/or special cautery units like ligasure
Which branches of the main splenic artery and vein should you preserve?
- those to the left lobe of the pancreas
What do you ligate the main splenic artery with?
- Silk suture
For smaller vessels, what can you ligate vessels with?
- Suture
- Metal clips/suture
- Ligasure (sophisticated electrocautery)
How can compromised liver function impact your surgical patient (6 primary reasons)
a. Decrease in compounds made by the liver such as albumin, glucose, and decrease in clotting factors needed for hemostasis
b. Neurological signs due to hepatic encephalopathy
c. Difficulties with drug metabolized by the liver (e.g. barbiturates, phenothiazines)
d. Difficulties with drugs that are protein bound (e.g. diazepam)
e. Anemia (due to nutritional deficiencies, coagulation abnormalities, or GI hemorrhage)
f. Coagulopathy
What should you do before performing a biopsy (percutaneous or intra-op) of potentially vascular tissue (e.g. liver, spleen, kidney, neoplasia) and before doing surgery in a patient with liver disease to make sure it is safe?
- Coagulation tests (PT/PTT)
Blood supply to the liver
25% via hepatic artery (25%)
75% via portal vein (75%)
Which of the vessels (hepatic artery or portal vein) is required for life?
- Portal vein
Name the 6 lobes of the liver from left to right
- Left lateral, left medial, quadrate, right medial, right lateral, caudate process of the caudate lobe
Which lobe has two processes? Name the lobe and the processes
- Caudate lobe - caudate and papillary process
Where is the gallbladder relative to the lobes of hte liver?
- Quadrate process and right medial liver lobe
Guillotine technique for liver biopsy
- Suture cuts through parenchyma and settles on vessels and bile ducts, ligating these structures
What do you fill the biopsy hole with if you use a dermal biopsy punch?
- Gelfoam which serves as a framework for clot formation
Describe guillotine with transfixation liver biopsy technique
- Make two 2mm nicks in the edge of the liver with Metzenbaums
- Back the needle through the liver
- Tighten in one notch with two throws
- Tighten in the other notch with 4 throws
- Biopsy the piece
How can you slow severe bleeding from the liver intraoperatively?
- Manually hold off the hepatic artery and portal vein where they are accessible along the ventral border of the epiploic foramen (Pringle maneuver)
Non-neoplastic condition dfdx for a liver mass
- Extramedullary hematopoiesis
- Nodular hyperplasia
- Cyst (if symptomatic, resect/drain/omentalize)
- Abscess (tx includes antibiotics, resect/drain/omentalize)
Dfdx and prognosis for neoplastic conditions in the liver
- Hepatocellular adenoma (curable with surgery!)
- Hepatocellular carcinoma (if localized, can survive >1 year postop)
- Bile duct carcinoma (high metastatic rate, poor prognosis)
Diagnostic plan for working up a patient with a liver mass
- We didn’t fill it out
- I think CBC/Chem/UA
- Thoracic radiographs
- Abdominal Ultrasound
- FNA or biopsy of the liver
- PT/PTT
Liver surgery - who does it?
Experienced surgeons only
Which bacteria to target for liver surgery?
- Gram negative aerobes and anaerobes
How much of hte liver can you remove and still get regeneration by hypertrophy and hyperplasia back to normal liver mass in 6 weeks in a healthy dog?
- 70-80% of the liver