Section: Surgical Oncology Curriculum: Curriculum, page 70

General

Restores the normal control of glucose metabolism
- Obviates the need for insulin in DM pts
- Reduces the progression of secondary complications
  - Retinopathy, peripheral vascular disease and nephropathy

Patient selection

Advantages have to be weighed carefully against the risks of both the transplant procedure itself and the immunosuppressive therapy
- For most patients, risks justified only when Kidney transplant for diabetic nephropathy also being undertaken
- In USA ~ 50% of all diabetics undergoing kidney transplantation also receive a pancreas transplant
  - Most cases, from the same donor
Three groups
- Simultaneous pancreas-kidney transplantation (SPK)
  - These patients do the best
  - Difficult to procure kidney and pancreas at same time.
- Pancreas after kidney transplantation (PKA)
  - These patient still do well
  - Can be easier in terms of procurement (PTA)
- Pancreatic transplantation alone
  - Limited indications as most patients do better taking life-long insulin
  - Intractable hypoglycaemic unawareness and cardiac autonomic neuropathy are indications
  - Other indications more ambiguous.

Whole pancreas together with a segment of duodenum
Graft is placed intraperitoneally in the pelvis
- Usually on the right
- Kidney graft is placed on the left
Donor vessels of the pancreas graft are anastomosed to the recipient iliac vessels
Exocrine secretions
- Enteric drainage - Anastomose the graft duodenum to the small bowel, often via a Roux-en-Y loop
- Urinary drainage – Duodenum anastomosed to the bladder
  - Urine amylase can be used to measure graft function
  - But urinary complications more common
Pancreas starts to function immediately
- Insulin may be required for the first few days

Usually occur early
Vascular thrombosis of the graft (5%)
Anastomotic leaks
Wound infection occurs in up to 10%
- Intra-abdo infection relatively common
Complications of enteric exocrine drainage include:
- Intra-abdominal Sepsis
- Adhesive SBO
Complications of bladder exocrine drainage include:
- Bladder/duodenal anastomotic leaks
- Cystitis (because of the effect of pancreatic enzymes)
- Urethritis/urethral stricture
- Reflux Pancreatitis
- UTI
- Haematuria
- Metabolic Acidosis (from bicarb loss in the urine)
- In 20%, complications are so severe that conversion to enteric drainage is needed
Acute rejection common, tends to respond to steroids
Elevation in blood glucose is a late sign, often indicates graft is unsalvageable
- Use serum creatinine, amylase and lipase initially

Aim: prolong life in diabetic pts who otherwise have high mortality rates at 10 years after receiving a kidney transplant alone
Provides freedom from insulin and improves quality of life
Results improved significantly over the last decade
1-year patient survival rate is > 95%
1-year graft survival rates for pancreas and kidney grafts are 85% and 95% respectively
Most deaths due to cardiovascular complications or overwhelming infection
Results of pancreas alone are not as good as combined
Acute rejection is more difficult to monitor in the absence of a kidney allograft

More attractive concept
- Major surgery and potential complications of transplanting entire pancreas avoided
Pancreatic islets for transplantation are obtained by mechanically disrupting the pancreas after injection of collagenase into the pancreatic duct
Islets then purified from the dispersed tissue by density-gradient centrifugation
- Can be delivered into the recipient liver (the preferred site for transplantation) by injection into the Portal Vein
Prev poor results, now better with sequential islet transplantation from 2-3 donors
Attempts made to protect islet cells from rejection
- Encapsulating them inside semi-permeable membranes
- Designed with a pore size that allows insulin to pass through but prevents antibodies and leucocytes from reaching the islets
  - Thereby avoiding need for immunosuppressive therapy
- A major attraction of this approach is that islets isolated from animals can be used and bioartificial pancreas grafts containing xenogeneic islets are currently under evaluation