Diabetes mellitus is a very common pathology in our daily practice and a pancreatic transplant is a specific treatment for some selected type-1 diabetic patients.
The aim of this surgical technique is to provide the patient with sufficient functioning beta cell mass that helps restore the normal blood glucose levels.
Thus,
the long-term complications of insulin-dependent diabetes decrease and this improves the survival rates.
The most common approach is through a whole-organ pancreas transplant,
normally in conjunction with a kidney transplant.
There are three main types of pancreatic transplant: simultaneous pancreas-kidney transplant (SPK),
pancreas-after-kidney transplant (PAK) and pancreas transplant alone (PTA).
SPK: is the most frequent form of pancreatic transplant.
It has the additional advantage that the serum creatinine level may be used as a sensitive a marker of both renal and pancreas graft rejection.
Recommendation: diabetic patients < 55 years old manifesting end stage renal disease.
PAK: pancreas transplant is performed if the initial kidney transplant was successful.
Recommendation: diabetic patients < 55 years old with severe secondary complications.
PTA: only a small percentage of diabetic patients are candidates to this treatment.
Recommendation: diabetic patients who have not manifested diabetic nephropathy yet and who experience frequent episodes of hypoglycemia.
Surgical technique and anatomical considerations:
Knowledge of the normal appearance of the pancreas graft and its vascular and enteric connections is essential for an optimal understanding of the imaging findings in the different imaging techniques.
The pancreatic graft is removed with the donor duodenum and vascular support,
and it is placed in the right lower peritoneal cavity or pelvis.
Therefore,
we have to know about the arterial supply,
the venous drainage and the exocrine secretion drainage of the pancreatic graft.
Arterial supply:
Components:
Donor superior mesenteric artery (SMA): supplies the head of the pancreatic graft through the inferior pancreaticoduodenal artery.
Donor splenic artery (SA): supplies the body and tail of the pancreatic graft.
Donor common,
internal and external iliac arteries: they forming the “Y graft”,
a vascular component to attach the donor SMA and SA to the vascularity of the recipient.
Recipient common or external iliac artery: it is anastomosed to the donor common iliac artery of the “Y graft”.
Venous drenage: It contains pancreatic endocrine secretions.
Components:
Donor portal vein (PV): is the main graft vein.
Recipient superior mesenteric vein (SMV): it is anastomosed to the donor PV.
Recipient iliac vein (IV) or to the inferior vena cava (IVC).
There are two techniques: portal o systemic venous system.
Portal venous system: donor PV is anastomosed to the recipient SMV. It is more physilogical,
with less complications.
Systemic venous system: donor PV is anastomosed to the recipient IV or to the IVC.
Exocrine secretions:
There are two types of drainages for the exocrine secretions: enteric and bladder drainage.
Enteric drainage:
It is the most commonly used in all types of pancreatic transplants (SPK,
PAK and PTA).
Components: donor duodenal stump and recipient small bowel.
Surgical technique: anastomoses between the donor duodenal stump and the recipient small bowel,
with or without the creation of a Roux-en-Y loop.
Location: mid abdomen to the right of midline,
with the head of the pancreas graft inserted cranially (for portal venous drainage) or caudally (for systemic venous drainage).
Bladder drainage:
Less physiological technique.
Metabolic and urologic complications.
Components: donor duodenal stump and recipient bladder.
Surgical technique: anastomosis between the donor duodenal stump and the superior aspect of the bladder.
Location: right side of the pelvis,
with the head of the pancreatic graft situated caudally.