was porous and had to be broken up into crumbs in order to easily fit it into the small chamber given these inaccuracies we did not attempt to evaluate quantitatively the chamber tissue and looked at the more qualitative aspects of the device such as morphology of the newly formed tissue patency of the vessels was determined at microsurgical exploration and via india ink perfusion studies if the vessel was extensively thrombosed within the chamber it was usually possible to see this under the operating microscope however ascertaining definitive patency was not always possible therefore india ink perfusion studies were performed under general anaesthesia on each animal prior to sacrifice under the operating microscope the groin incision was reopened and the chamber exposed taking care not to damage the pedicle a laparotomy was then performed and the abdominal aorta was dissected free of the vena cava and cannulated just below the renal vessels using a fine 30g bore silicone tube this was then flushed using heparinised saline to ensure that the cannula was in the correct position next a solution of neat commercial india ink containing 10 i u heparin per ml was infused under gentle hand pressure using in a pulsatile fashion until the animals liver.