Developments in live donor renal transplantation

Developments  in live  donor renal transplantation

     Live Kidney donation is assuming a prominent role in renal transplant  programmes because of the persistent increase in patients requiring  definitive treatment  for end- stage renal failure . While cadaveric transplant rates remain more or less static, live donor transplantation  has increased 3-fold in US over the past  decade,  where  it now accounts for 43% of renal  transplant  activity. Figures of United Kingdom  Transplant  indicate 24% of all  renal transplants were from live donors for the  year  2003-2004. Superior recipient  post -transplant outcome  compared  to cadaveric Kidneys, the potential for transplantation  before  dialysis , and the ability to plan the procedure ( allowing optimisation of recipient condition ) justify this growth  in live donation. New techniques and novel approaches have been developed to facilitate live donation  and  increase  transplant activity.  This chapter presents some of the important recent developments and controversies in live  donor renal

PRE- OPERATIVE IMAGING OF LIVE RENAL DONORS

   PRE- operative imaging of live donors is mandatory for a number of reasons it confirms the presence of two functioning Kidneys, identifies their position, indicates adsence of pathology that would preclude donation, and provides  anatomical information  necessary for planning  the procedure.  The ideal form of imaging is minimally invasive and provides accurate morphological information  on the  renal parenchyma , collecting system and vascular anatomy. Traditionally , imaging has been performed using  angiography, but there are inherent risks with this invasive  procedure . Venous imaging  is limited  with arterial contrast injection, and  separate excretion  urographic studies are  necessary to visualise the collecting  system. These  disadvantages have been the driving force  behind the introduction of computed tomographic  angiography(CTA) for anatomical assessment of living renal donors. CTA is non-invasive and cheaper than other imaging techniques. Pre- operative anatomical  information is, of course, necessary for open donor nephrectomy, but it assumes paramount importance in the laparoscopic procedure because of reduced  exposure, and  particular difficulties in the identification of complex  renal vein  tributaries. Thus, the location , size and number of renal veins and  tributaries need  to be described  accutately pre- operatively. Spiral CTA  imaging compares favourably with conventional angiography  in the prediction   of gross renal arterial  and venous anatomy and  is a powerful tool for identification of renal vein tributary anatomy.

   Prior to imaging , all potential donors are assessed  by physical examination , undergo blood group and HLA  matching with the intended recipient, complement- dependent  cytotoxicity cross - matching , and isotope GFR measurement . At the Leicester unit, CTA is performed  on a spiral GE Prospeed  SX scanner. Arterial and venous anatomy is evaluated using a dual phase protocol with venous injection of iodinated  contrast media (Iopamidol).Arterial phase imaging is performed from the level  of the  coeliac axis orgin to include the lower renal  pole.  Venous phase  imaging (60 s after contrast  injection ) includes the  cephalo - caudal  extent of the left renal  vein and  the left  renal  sinus.

DEVELOPMENT OF MINIMAL  ACCESS DONAR NEPHRECTOMY

     The live donor nephrectomy operation has traditionally been performed through an open incision ,necessitating  a prolonged period of recovery. This, and the cosmetic implications of a large  flank wound may be discouragements to potential donors.
      To reduce such disincentives , there has been a move towards minimally invasive donor nephrectomy, first performed  as a classical  transperitoneal laparoscopic procedure (LapDN) by Louis Kavoussi and Lloyd Ratner in 1995. Retrospective  reports  suggest LapDN is associated with decreased severity and duration of postoperative pain , shorter  in- patient stay, quicker return to work  and normal  activities, and  improved cosmetic result  when compared  to open donor nephrectomy. Furthermore, the overall  societal cost of LapDN is lower and recipient  quality of life scores are higher.
   Despite the current lack  of published statistically  powered randomised clinical trials, retrospective data suggest that minimal access donor nephrectomy not only offers  postoperative advantages to the donor but also increases the number of transplants performed by reducing donor disincentives: estimates range  from a 25% to 100% increase in transplant activity.  In the US, 31% of live kidney donor procedures  are performed  laparoscopically, and 65%  of centres offer the procedure. Despite  encouraging  UK figures indicating  year- on -year increase in  live donor activity, few centres have adopted minimally invasive techniques. With  accumulating evidence that high quality grafts can be procured from  laparoscopically- procured kidneys, the main hurdle for expansion of  laparoscopic donor nephrectomy is lack of operative experience of the technique  amongst UK  transplant surgeons. Three approaches  have been described  and  advocated, comprising  transperitoneal, extraperitoneal, and  hand - assisted live donor nephrectomy. The  hand- assisted operation is said to be easier  to learn than transperitoneal laparoscopic donor nephrectomy, and can be safely  and efficiently performed by surgeons with less laparoscopic experience.  The  retroperitoneal approach  avoids breaching the peritoneum, and may also have a particular application in right donor nephrectomy.