CYBERMEDICS
                                                                         © 1999, Venkatesh.K.S
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MAJOR TRANSPLANT SURGERIES

TABLE OF CONTENTS

INTRODUCTION
LIVER
PANCREAS
KIDNEY
HEART &LUNG
BONEMARROW
 

INTRODUCTION

ORGAN DONATION

Live donation of organs or tissues is an established procedure today, especially in the fields of Kidneys, liver etc.Persons with two normally funcioning Kidneys may donate one of them, the risk of mortality being 1 in 3300 in a study conducted, with virtually no risk to the long term health of the donor.Live donation of unpaired organs has obvious difficulties,but successful live donation of segments of the liver and bowel has been undertaken, usually into childern from patients, although the safety of the procedure is still controversial.

CADAVERIC ORGAN DONATION

In most countries of the world the principal source of the organs for transplantation is cadaveric donation.The legal, ethical and religious principles vary, but many countries accept the concept of brain death which allows organ donation from beating heart donors.The donor must be carefully resuscitated before organ donation, the exact requirements depending on the cause of the death, but reversal of dehydration is commonly required, as are inotropes to maintain cardiac and urine output.The additional treatment with hormones such as thyroxine is controversial.Multi-organ donation should the rule, although there are practical age restrictions for use of livers (<60 yrs) and hearth (<50 yrs), and although renal dose dopamine is acceptable, higher doses of inotropes cause poor function of the heart after transplantation.Donor criteria are particularly stringent for lung donation, where pathological conditions such as infection is a frequent contraindication.

PRINCIPLES UNDERLYING ORGAN DONATION PROCEDURES

The perfusion fluids for organ donation vary for different organs and the constituents also vary considerably.It must be noted that they are not safe for organ perfusion in the living body, because many have a high potassium content.

The organs are packed in atleast 3 sterile plastic bags, then stored on ice for transport.COld pulsatile perfusion systems employed by certain centres appears to prolong the acceptable cold-ischaemia time.The duration for which an organ may be safely kept before transplantation varies depending on the organ, but is shortened if there is added warm ischaemia or if the donor is old.The viability of the organ beyond this safe-time then progressively deteriorates, although the consequences for some organs, such as the heart are more serious.

CHOOSING THE RECIPIENT

Recipients now, are no longer restricted to young, relatively fit patients.This applies to patients aged>70yrs also.All patients should be given a frank explanation of the procedure, the side effects and the risk to benefit ratios.The choice of the recipient must take into account the blood group of the donor, the HLA match and how long the recipient has been watching.Other clinical and virological aspects may also be considered.

LIVER TRANSPLANTATION

IMAGE ORTHOTOPIC LIVER CONSTRUCTION WITH VASCULAR ANASTOMOSIS
IMAGE VENOUS BYPASS FROM THE VENACAVA AND PORTAL SYSTEM TO THE SUPERIOR VENOUS SYSTEM
IMAGE FUNCTIONAL DIVISIONS OF THE LIVER AND THE SEGMENTS
 
Liver transplantation has grown from a largely experimental procedure, first carried out 35yrs ago, to a well established treatment option for patients with advanced liver disease. Complete knowledge of the surgical anatomy related to the liver is essential for both the donor harvesting operation and the recepient operation.The shortage of paediatric donors has resulted in the rapid development of innovative surgical techniques where adult donor grafts are reduced in size to two or four segments to implant into children.

Starzl performed the first human liver transplantation in 1963.The early cases were all unsuccessful, but a further series by Starzl in 1967 paved the way to current success.The operative technique and degree of difficulty of liver transplantation is affected in a major way by the cause of liver failure and particularly by the presence of adhesions from previous surgery.In chronic cirrhosis, these adhesions can become extremely vascular because of portal hypertension, making the dissection and removal of the liver before transplantation one of the most difficult surgical procedures. For this reason it is important that patients likely to come to eventual liver transplantation should not be subjected to other surgery unless the procedure is life-saving.If surgery is absolutely necessary (for eg:- to transect the oesophagus for bleeding varices unresponsive to other therapy), then avoiding anterior approaches near the porta hepatis, for example by a left flank, approach is useful.

In parallel with the difficulty of surgery, anaesthesia of patients for liver transplantation is equally or more critical to the outcome, involving the control of wild swings in virtually every physiological system.These changes include circulatory volume depletion as blood is lost, major stress on cardiac function as the venous return to the heart is halved during venacava cross clamping, changes in pH and electrolytes due to influx of metabolites and preservation fluid from the new liver, and major defects of coagulation, temparature control and glucose homeostasis.To control these changes requires an experienced anaesthetist team to undertake careful pre-operative assessment, particularly to exclude or assess any complicating defect of other organs, and intensive monitoring during the operation with adequate technical and laboratory backup close at hand.

DONOR LIVER REMOVAL

The conventional textbook description of a single hepatic artery arising from the coeliac trunk is seen in only 60-65% of cases, with anatomical variations being present in over one third of the cases.The commonest variations are a replaced or accessory left hepatic artery from the left gastric artery (20%), and a replaced or accessory right hepatic artery arising from the superior mesentric artery (15%), running posterior to the common bile duct.Occasionally both variants may be present together (5%), or the entire hepatic arterial supply may be derived from the superior mesenteric artery ro from a common coeliacomesenteric trunk.Identification of the arterial supply is essential prior to perfusion to cool and preserve the donor organs. To remove the liver from the donor, the common bile duct is divided just above the pancreas, the gallbladder incised and the bile flushed out prior to cooling, to prevent bile-induced epithelial injury. After cross-clamping the aorta above the level of the coeliac axis, cooling of the liver is achieved by portal venous and aortic perfusion with the University of Wisconsic solution (UW) at 4*C.The liver retrieval is completed, preserving an adequate length of inferior venacava (IVC), the coeliac trunk with an aortic patch, and a suitable length of portal vein. In addition, the common and external iliac arteries and veins are retrieved in the event that a vascular reconstruction is necessary, eg. because of portal vein thrombosis, or arterial vascular reconstruction.The graft is then preserved for upto 18 hrs in UW at a temparature between 0-4*C.
 

RECIPIENT OPERATION

The use of UW has permitted safe prolonged storage times, so that this operation is usually performed as a semi-elective procedure during the day.The removal of the recipient'd diseased liver is usually undertaken in the presence of portal hypertension, often with previous biliary or portal surgery, and occasionally with additional technical problems such as portal vein thrombosis or extensive varices.The structures in the porta hepatis are systematically divided close to the liver hilum, the hepatic artery, the common hepatic duct and the portal vein.Most centres make use of a venovenous bypass in adults during the anhepatic phase, where blood is pumped from the portal and femoral vein to the axillary vein;its advantages include decompression of the clamped IVC and portal system, providing adequate circulating blood volume and venous return, thereby allowing for a more controlled anhepatic phase. Next the IVC is identified below the liver and the left and right triangular ligaments are divided and the bare area of the liver is dissected off the diaphragm.The suprahepatic IVC is then dissected and encircled.The hepatectomy is completed after placing supra- and infrahepatic IVC clamps.An alternative technique called the 'piggy-bank' technique leaves the entire recipient IVC in place, with the ligation of the individual short hepatic veins, particularly from the caudate lobe. After achieving full control of bleeding, the new liver, which has been dissected and prepared on a sterile trolley, is implanted into the recipient: the upper IVC anastomosis first, the lower IVC next followed by the portal vein using a continuous vascular suture. The UW within the liver is next washed out.The graft is then reperfused with blood via the portal vein.The arterial anastomosis is usually made between the donor and recipient common hepatic arteries.In the event of a donor left hepatic artery from the left gastric, no reconstruction is necessary,the coeliac trunk being used for the anastomosis.A donor right hepatic artery arising from the superior mesenteric artery requires some additional reconstruction, most commonly this is anastomosed to the donor splenic artery stump.Not infrequently, especially in patients undergoing transplantation for hepatic artery thrombosis, it is often impossible to achieve an adequate arterial inflow from the coeliac trunk, and a donor iliac artery aortic conduit is constructed from the recepient infrarenal aorta to the donor hepatic artery.Portal vein thrombosis is no longer a contraindication to liver transplantation, and successful portal revascularization can be obtained by thrombectomy, dissection posterior to the pancreas downt to healthy portal vein, use of large collaterals, eg-left gastric vein, or by means of a donor iliac vein graft from the recepient superior mesenteric vein to the donor portal vein.

REDUCED SIZE LIVER TRANSPLANTATION

The majority of children with liver disease present this condition in infancy and early childhood.It is in this group that there is a great shortage of donor organs.Over the past decade, many groups have shown that it is safe to implant reduced size grafts, with a reduction in waiting time, fewer deaths on waiting lists, and with no increase in complications related to the reduction process.These techniques allow a donor-recipient weight discrepancy of upto 10:1, when only segments 2 and 3 are transplanted.The back-table reduction operation entails a meticulous hilar and intrahepatic vascular and biliary dissection, dissection of the left hepatic vein, and the parenchymal resection just to the right of the falciform ligament.In larger children or when the discrepancy is less than 4:1, the right lobe (segments 5-8) may be utilized. The splitting of a single donor liver into right and left lobes, thus benefitting two recipients, is also an established procedure,where the vessels to one of the two halves have to be lengthened using donor vessels.A few centres have gone one step further, in an effort to further reduce the waiting period, to partial transplants from living relations, where segments 2 and 3 of a parent's liver are transplanted into a child.Over 100 such transplants have been performed worldwide, particularly in the United States and Japan, with low donor morbidity and excellent short and longterm results. In conclusion, liver transplantation has developed into a major effort to support patients with advanced liver disease.Although the techniques have been standardized, it remains a difficult and complex procedure. A complete knowledge of the anatomic variations in arterial supply,venous anatomy, as well as the segmental anatomy of the liver, is an essential prerequisite to developing surgical skills for this form of surgery.

POST-OPERATIVE CARE

After liver transplantation, the initial management follows standard intensive care, continuing the monitoring and attempted homeostasis started during anaesthesia.About a quarter of the patients will show rapid return to normality of all biochemical and physiological derangements, leading to weaning from the ventilator and return to the ward within 3 days.However, most patients will show some degree of early graft dysfunction, mostly as a result of cholestasis related to preservation or predonation injury.These patients may remain unconscious and have circulatory, clotting and electrolyte disorders which require continuing support.Slow recovery is to be expected in most of these cases, but the development of severe complications must always be excluded, as they require urgent action.

The development of rejection is less frequent than after kidney transplantation, usually coming on from 7 days onwards.Rejection usually presents as increasing graft dysfunction and must be distinguished from ischaemia, biliary obstruction and sepsis.Ultra sonography with color duplex scanning has greatly eased the diagnosis, and biopsy of liver helps distinguish rejection from infection.In the long term, the complications of immunosuppression are a problem, as after kidney transplantation, but one encouraging feature of liver transplantation is that there is less tendency to lose grafts late after the operation from chronic rejection (which usually manifests itself as 'vanishing bile duct syndrome' when it occurs).

SURGICAL COMPLICATIONS AFTER LIVER TRANSPLANTATION

COMPLICATIONS

  • Rejection
  • Haemorrhage
  • Portal thrombosis
  • Hepatic artery thrombosis
  • Bile leak
  • Cholangitis
  • Biliary stricture

FEATURES

  • Poor graft function
  • Oliguria,CVP,Low BP
  • Graft non-function
  • Delayed liver necrosis
  • Peritonitis
  • Septicemia, reduced graft function
  • Decreased graft function

DIAGNOSIS

  • Biopsy
  • Biopsy
  • Clinical + Ultrasonography
  • Duplex scan
  • Duplex scan
  • T-tube cholangiogram
  • Biopsy, bile culture
  • Ultrasonography

TREATMENT

  • Immunosuppressive therapy
  • Retransplantation if severe
  • Correct clotting, re-exploration
  • Re-transplantation
  • Early exploration and thrombectomy
  • Re-exploration
  • Antibiotics
  • Re-exploration or stenting

INDICATIONS AND OUTCOMES FOR ADULT LIVER TRANSPLANTATION

 5-year Graft Outcome
Alcoholic cirrhosisvariable*
Drug or toxin induced--hepatic failureGood
Viral hepatitis Fair
Chronic active hepatitis Good
Primary biliary cirrhosis Good
Hemochromatosis Good
Budd-Chiari syndrome Good
Hepatocellular and --CholangiocarcinomaPoor
Liver metastaseSVery poor

Good=60-90% 5-yr survival
Fair=30-60% 5-yr survival
Poor=10-30% 5-yr survival
*dependent on psychosocial factors etc

CURRENT RESULTS AFTER LIVER TRANSPLANTATION

These are influenced by the selection of patients transplanted as much as anyother factor.Excellent results can be obtained if recipients are confined to young patients with non-malignant disease, non-alcoholic cirrhosis, and fulminant hepatic failure is excluded; better than 90% of 1-year survival can be expected.To some extent the current shortage of donors justifies this selection approach.The challenge is to transplant the less favourable group, particularly those with fulminant liver failure where the longterm outcome of successful transplantation may be expected to be excellent.

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PANCREATIC TRANSPLANTATION

IMAGE PANCREATICO-CYSTOSTOMY WITH DUODENAL CONDUIT
IMAGE PANCREATICO-CYSTOSTOMY WITH CUT SURFACE OF PANCREAS ANASTOMOSED TO BLADDER
Pancreatic transplantation is indicated for the treatment of insulin dependent diabetics who suffer end-stage renal failure due to diabetic micro-angiopathy;in these cases a kidney is transplanted into the same recipient, usually from the same cadaveric donor.A pancreas may also be transplanted alone in an unstable diabetic in whom renal or other end-organ failure may be anticipated in the near future.The major technical challenge has been to develop a method of drainage of the exocrine pancreatic secretions and to prevent a pancreatic fistula.To achieve these ends, a roux-en-y loop of jejunum has been used in the past, but the technique of pancreaticocystostomy is now much more popular.The pancreas is always transplanted into the pelvis, either within or outside the peritoneal cavity.In this position, the pancreas can be drained into the bladder or into the smallbowel loop, either using a duodenal conduit, or by anastomosing the cut surfaces of the pancreas to the fundus of the bladder.The bladder anastomosis offers the technical advantage of being an easier operation, and the function of the gland may be measured by regular measurement of urinary amylase.In immunosuppressed diabetics, where healing is impaired, pancreaticocystostomy seems the safest and technically most successful operation.

OPERATION OF CADAVERIC PANCREATECTOMY

Following the diagnosis of brain death, the pancreas is dissected free of the transverse mesocolon, and the attachments to the greater curvature of the stomach, including the short gastric vessels, are divided.The splenic vessels are tied at the pancreatic tail and the spleen removed, and the splenic and coeliac arteries, including the superior pancreatico-duodenal artery, are prepared for anastomosis to the recipient artery.If the whole organ is to be transplanted, the duodenum is divided, and the superior mesenteric trunk and the inferior pancreatico-duodenal artery are preserved.Since the liver will also frequently be taken for purposes of transplantation, the viscera are reperfused throught the aorta with a precooled preservation solution and are excised.A patch of aorta bearing the superior mesenteric and coeliac arteries may be removed, together with a length of portal vein for anastomosis to recipient vessels.'Jump graft' using sections of iliac artery and vein may be needed to provide tension free anastomoses with the recipient's circulation.

RECIPIENT OPERATION

The coeliac and the superior mesenteric arteries are anastomosed to the external iliac artery, and the portal vein to the external iliac vein using a jump graft if necessary.Angulation must be avoided to avoid a high-risk of postoperative thrombosis.The cut pancreatic surface, or the duodenal conduit, are anastomosed to the vault of the bladder.

 

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KIDNEY TRANSPLANTATION

Transplantation of the kidney is now recognized as the definitive treatment of end-stage renal failure.Although kidneys from compatible living relatives may be used, the commonest source of donor organs are patients who die during intensive care for lethal head injury or intracranial haemorrhage.Dramatic advances in the pharmacology of immunosuppression have led to greater longterm success in graft function and patient survival:rejection of the graft is preventable in some cases and is successfully treated in the majority of cases when it occurs.70% graft survival after cadaveric renal transplantation is now reported five years after the operation described here.

For technically successful transplantation of the kidney to be carried out, the following criteria must be met:

Provided these criteria are met, kidneys taken from brain dead, heart-beating donors may be stored for periods upto 72 hours and re-implanted with a good prospect of immediate function.

DONOR KIDNEY

The native human kidney lies in the retroperitoneal space, deriving its blood supply from the aorta via the renal arteries, and its venous drainage entering directly into the inferior venacava on each side through the renal vein.Vascular anatomy may vary: usually the renal artery is single, but renal arteries may be multiple in approximately 15% of cases.Each renal artery is an end artery (i.e. intrarenal anastomoses with accessory arteries do not occur).Collateral venous anastomoses do, however, occur within the renal substance, between the main renal vein and accessory veins.From the surgical point of view, therefore, the establishment of a complete blood supply to the donor kidney requires that all the accessory arteries must be joined to the recipient's circulation, whereas accessory veins may be ligated and the venous drainage established by anastomosing the main renal vein to the recipient's venous system.The renal artery commonly divides into two or three subsidiary branches near the hilum of the kidney, and the inferior of these branches frequently gives rise to arterial twigs which supply the upper third of the ureter, which must be preserved.

RECIPIENT OPERATION

The donor kidney need not be placed orthotopically in its 'natural' position;indeed there are anastomical advantages to transplanting kidney into the pelvis.The iliac fossa is anatomically receptive to a renal transplant.The time-honoured technique invented by Murray utilizes an extra-peritoneal approach to the iliac fossa which allows ready access to the iliac artery and its branches, and the external iliac vein, to which the donor vessels may be joined;the recipient bladder and ureter are nearby, enabling the surgeon to achieve a satisfactory junction for urine to drain into the bladder, using a small length of the upper ureter, with its own blood supply deriving from the renal artery.

 

TECHNIQUE

The arterial anastomosis: when the donor kidney is removed from a cadaver, a patch of aorta bearing the renal artery of arteries greatly facilitates the anastomosis of the patch to the external iliac artery (Fig I)
IMAGE FIG-I Renal arteries of donor joined to ext.iliac artery of recipient. IMAGE FIG-III Anastomosis of renal arteries to ext.iliac artery.
IMAGE FIG-II. End-end anastomosis of donor renal artery to int.iliac artery of recipient. IMAGE FIG-IV.Technique of surgical anastomosis of renal arteries.
Kidneys taken from living donors usually have a single main artery.Under these circumstances, the main artery is best anastomosed to the end of the internal iliac artery, after division of the distal end, and reflection of its proximal end to enable junction to the renal artery to take place (Fig II). If an inferior polar artery exists, it is commonly inferior and may be joined end to end to the inferior epigastric artery. Exceptionally two 'main' renal arteries are found which may have to be spatulated (joined together side-to-side for a short distance to form a common osteum) and then anastomosed conjointly to the side of the external iliac artery (FIG III & IV). Small polar arteries less than 1 mm in external diameter may be sacrificed provided that the area of cortex supplied by such an artery does not exceed an area 3 cm in diameter.Failure to anastomose bigger polar arteries than this risks necrosis of the cortex and calyceal fistula with urine leak.

  The venous anastomosis: The biggest donor vein is chosen to join to the recipient vein, and other branches may be sacrificed safely on account of the intrarenal venous anastomoses.Provided that a suitable length of donor vein is available, the renal vein may be joined safely to the external iliac vein.

  two techniques have been developed to join the donor ureter to the recipient urinary tract: implantation of the ureter into the bladder and anastomosis of the donor ureter or renal pelvis to the recipient ureter (ureteroureteral anastomosis).

IMPLANTATION OF THE URETER INTO THE BLADDER

On-lay technique:
IMAGE FIG-V. The on-lay technique of Uretero-cystostomy. IMAGE FIG-VI. Cross-section of completed On-lay ureterocystostomy.
the ureter is spatulated by incising one side of its distal end 1 cm proximally, the bladder muscle is incised over its supero-lateral aspect so that the mucosa bulges forward for a length of 3 cm; the lower 1 cm of the bladder mucosa is opened and is stitched with an absorbable suture to the spatulated ureter (Fig V).An anti-reflux mechanism is then created by approximating the bladder muscle over the distal end of the ureter (FIG VI).

  The 'ureteroneocystostomy' (anastomosis of the ureter from within, using a wide opening in the bladder)
Here, the dome of the bladder is widely opened and a tunnel is created throught the bladder muscle approximately 1.5cm in length.

IMAGE FIG-VII. The 'ureteroneocystostomy' seen in cross-section.
The donor ureter is then drawn down through this tunnel, spatulated and the ureteric mucosa is joined to the bladder mucosa using interrupted absorbable sutures.This technique allows the ureter to prolapse into the lumen of the bladder, forming a 'nipple' ureteroneocystostomy.After healing, the bladder muscle which embraces the lower end of the ureter acts as an effective anti-reflux mechanism.During contraction of the bladder wall during micturition, the ureteric lumen is closed by contraction of the bladder muscle, which prevents reflux up the donor ureter and thus minimizes the risk of infection or obstructive uropathy (Fig VI). The dome of the bladder is then closed to ensure a urine-proof junction.After on-lay ureterocystostomy, or ureteroneocystostomy, a bladdder catheter is left insitu for 5 days, to protect the bladder and ureteric anastomoses from back pressure should post-operative urinary retention occur.

 

  • Uretero-ureteral anastomosis This is an alternative to the ureterocystostomy techniques described above.The donor ureter is divided 2-3 cms below the pelvi-ureteric junction and the recipient ureter is dissected over a short distance, care being taken to preserve blood supply.The proximal recipient ureter is ligated and divided.Both donor and recipient ureters are reciprocally spatulated and joined together using a single or interrupted layer of absorbable sutures.A plastic stent may be inserted across this anastomosis leading from the donor renal pelvis to the recipient bladder to prevent leakage of urine through the anastomosis during the healing phase.

    • Good anatomical insight & surgical techniques are essential to successful renal transplantation.Meticulous anastomosis of blood vessels, enabling early endothelial healing, will minimize the risk of vascular thrombosis and inevitable graft failure.The ureteric anastomosis must also be sound to prevent urine leakage which in an immunosuppressed patient recieving drugs to prevent rejection can lead to local infection and septicemia.

     
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