Transplant 101 Module 1 Part 2B - Surgical Techniques

Deceased organ donation

• Primary source of organs for transplantation

• multi organ procurement often involving multiple teams from differnet programs working at a remote location

Neurologically deceased donor

Donation after brain death

DCD

Donation after cardiac death

Principles of organ procurement

• identify and preserve import structures to allow reconstruction in the recipient

• perfuse the organ through its vasculature with a preservation solution

• Cool the organ

Laparoscopic donor nephrectomy

Incisions used for this kind of nephretomy become barely visible even 3 weeks post nephrectomy

Kidney Transplant

• Heterotopic - transplanted kidney is not placed in the same location as native kidney

• Transplanted kidney placed in new space in lower abdomen

• Right or left illiac fossa is exposed - illiac artery and vein usually externan ones - exposed and skeletonized

• once vessels ready venous anastomoses is performed- connect venal vein to external illiac vein

• renal artery connected to external illiac artery

• repurfuse - release clamps on blood vesssel

• Use a stent to connect ureter of transplanted kidney to bladder

External illiac artery

Artery that undergoes anastamoses to the renal artery in kidney transplant

External illiac vein

Vein that undergoes anastamoses to the renal vein in kidney transplant

Typical incision for kidney transplant

Oblique incision in lower right quadrant

Heterotopic procedure

• transplanted kidney is not placed in the same location as native kidney

End to side anastamosis

• most common anastamosis technique

• connects illiac vessels to renal vessels

End to end anastamosis

• less common anastamosis technique

• connects illiac vessels to renal vessels

Factors that impact the intraoperative course

• Vascular disease - ex. advanced atherosclerosis

• Number of kidneys to implant

  • sometimes double kidney tranpslant is performed - lengthen procedure

• More vessels and ureters - makes implantation more challenging

Anatomical variations in kidney transplant

• Multiple vessels

  • ex. donor kidney has two arteries instead of one

  • two arteries are connected together in a backtable procedure before they are anastamized as one artery to the recipient

• Multiple kidneys

  • double kidney transplant

  • implant both kidneys on both side or one on left side and one on the right

Liver Transplant - Types of Grafts

• Deceased donor

  • maybe whole liver

  • split liver transplant may occur - not often

    • left lateral segment of liver usually used for pediatric recipient

    • right lobe graft used for an adult recipient

• Living donor

  • most common at uHn - right lobe adult to adule can be used

  • left lateral segment can be procured for a pediatric liver transplant recipient

  • rarely - left lobe transplant peformed

Living donor hepatectomy

• done through upper midline incision maybe sometimes with a right subcostal incision added in

• First two hours verify liver anatomy - vasucular and billary structure

  • Cholangiogram - verify biliary anatomy of the donor

• 2 to 3 hours - parenchymal transection

  • Bile duct is carefully divided to ensure that it is not taken away from donor

• Donor is anticoagulated with heparin - major blood vessels to be removed and split up are divided

• Graft is removed and flush of graft with pefusion liquid is done

• final cholangiogram done to verify that the bile duct anatomy is intact in the portion remaining in the donor

- hepatectomy

• Total hepatectomy must occur in recipient

  • major consideration - significant bleeding can occur

  • involves cross clamp the portal vein and the inferior vena cava above and below the liver

Classical deceased donor full liver transplant- Anhepatic phase

• when the new liver is added in

• anastamosis of inferior vena cava above and below the liver as well as the portal vein anastamosis

  • major consideration in anhepatic phase

    • decreased venous return to heart - vasuclar challenges

    • anhepatic - absence of liver function - patients metabolism can be deranged - managed by anesthesia

Classical deceased donor full liver transplant- reperfusion

• Remove portal vein clamp and flush 300 ccs of first pass blood and venting it through inferior vena cava to wash out as much as the high potassium cold preservation solutoin in the liver graft

• inferior vena cava clamps released to restore circulation

• major considreations for surgery and anesthesia

  • hemodynamic instability from blood loss due to flushing of the liver

  • as well as effects on circultion of low pH high potassium blood from the liver graft into systemic circulation

Classical deceased donor full liver transplant- hepatic artery reconstruction

• After the reperfusion state

• reconstruct important artery

• takes about 30 - 60 minutes

• usually direct anastamosis from recipients native hepatic artery and donor hepatic artery can be done

• hepatic artery provides critical source of blood flow to billary tree in new liver

Classical deceased donor full liver transplant- bile duct reconstruction

• Last step of the process

• In these cases - direct connection between native bile duct and donor duct can happen

• Roux en hepaticojejunostomy may occur if compliations

• after done abdomen is closed

Roux en hepaticojejunostomy

• Occurs when native bile duct of recipient is unhealthy or of poor size - special procedure to connect to donor duct that takes another hour in the OR

Piggyback implantation

• Situation where the retorhepatic inferior vena cava is preserved in recipient rather than removed

• requires additional disection to mobilize liver off inferior vena cava

Partial liver transplantation

• Used most commonly at UHN for living liver transplant when donor graft from right lobe implanted into recipeint

• Can also be used in deceased donor split liver tranpslantation

• preserves inferior vena cava of recipient

• branches of hepatic veins are anastamosed to inferior vena cava directly

• this graft is move sensitive to cvp in recipient because it is smaller part of the liver so more predisposed to venous congestion

• sometimes amount of blood flow of liver into portal veins needs to be adjusted to reduce congestion - fixed through splenic artery ligations, splenctomy or portal cava shunt

• More common in split liver deceased donotion, less common in living donor - signficant bleeding from cut surface of liver parenchyma after reperfusion

Recipient portal vein thrombosis

• May require signficant variation in surgical technique

• Commmon solution is to place interposition vein graft from the recipients superior mesenteric artery to the portal vein on the graft

• superior mesenteric interposition graft is often done earlier before native hepatectomy

• ensures good inflow through portal vein graft established for placing the new liver in place and attemping reperfusion

Recipient hepatic artery stenosis and thrombosis

• Problems in arterial flow in recipients native hepatic artery due to stenosis or thromobosis

• most common solution - use a graft of illiac artery from deceased donor to construct an interposition graft from the recipients aorta to donor hepatic artery

• done before anhepatic phase and implating of new liver - arterial flow prepped for new liver

• partial infrarenal aortic clamp is required for graft - hemodynamic effect on recipient

Liver transplantation from DCD donors

• At UHN we infuse tPA (thrombolytic agent) to break up the microvascular thrombosis into hepatic artery before graft reperfusion

• yields a higher risk of post reperfusion bleeding and a prolonged period to return to hemostasis before return to operation

Patient factors impacting liver transplant intraoperative course

• Degree of liver dysfunction in recipeint can impact risk of bleeding

• degree of portal hypertension impacts the space for liver, ascites

• Collateral vessels and portal hypertension - impact ability to tolerate cross clamp

• Portopulmonary hyptertention and hepatopumonary syndrome - impact pulmonary outcomes and need for monitoring by anesthetia in surgery

• Previous surgerys such as liver transplant or resection can cause adhesions making surgery challengin

• Hepatic artery or vein thromnbosis extend surgery due to need for conduit grafts to establish good blood flow to graph

• Diagnoses such as cancer impact it

  • Cell saver device cannot be used for patients with hepatocellular cancer

• comorbidities such as cardiac, lung and renal disese influence degree of blood lost

Liver graft factors that impact intraoperative course

• Size of donor liver and type of flush solution for liver procurement - impact the amount of cold, low pH and high Potassium fluid released into recipient systemc

• donor age, steatosis (degree of fattiness of liver), size of donor liver and ischemic time and whether liver is got from (dcd ndd or ld)

  • impacts pH and level of coagulopathy

Function of Kidneys

• Each kidney has an artery and a vein associated with it

Kidney anatomy

• Each kidney has a cortex and a medulla

• made up of a million nephron

• Nephron = funtional unit of the kidney

• Kidney has high blood flow

• - Goes through glomerulus through the nephron, waste products eventually enter the ureter to be excreted as waste from the bladder

Chronic Kidney Disease

• Fluid retention in the lungs - causes pulmonary edema - build up of fluid in the lungs that compromises the function of gas exchange - can be fatal

• Uremia - consequences of build up waste products

  • fatigue

  • vomitng

  • seizures

  • pericarditis - inflammation of lining of the heart - can be

  • neuropathy - issue of nerves being not feeling

Hemodialysis

• Need acess to artery and vein (aka fistula)

• Blood flows into hemodialyzer and is cleaned of waste products and goes back into patients

• Helps maintain fluid and electrolytes

Peritoneal dialysis

• Catheter inserted in the peritoneal cavity

• Dialysate is pumped in through the catheter and helps to remove the waste products in the body

• pumped in and out of the peritoneum many times to achieve full filtration

Why is renal transplantation the superior intervention to dialysis in ESRD?

• Provides constant removal of wastes and homeostasis

• higher quality of life

• Survival is better on tranpslant

• cheaper cost to healthcare system

  • 50 k every year for dialysis vs 50 k investment in tranpslant and then 10 to 15 k in the following years