Intralesional injection of corticosteroids is an effective treatment for ca
pillary hemangiomas, Complications include embolisation of corticosteroid p
articles into the ocular circulation resulting in permanent loss of vision;
This research is aimed at developing an injection cannula and monitoring s
ystem to prevent such inadvertent embolisation. A cannula has been designed
to simultaneously estimate the pressure at its tip and the flow rate durin
g injection. The estimation technique has previously been validated using a
n in vitro model. In this study, the cannula was tested in vivo with canine
liver at injection flow rates of 2.5 to 21 ml min(-1). The pressure genera
ted in the tissue during injection was calculated using the technique devel
oped. This was compared with direct in situ pressure measurements made with
a coaxial outer cannula. The mean calculated pressure was seen to be linea
rly related to the mean measured pressure with a slope of 0.97, correlation
coefficient of 0.99 and standard error of 2.74 mmHg. Similar trends were o
bserved between the maximum calculated and maximum measured injection press
ure: slope = 1.0, r = 0.99 and standard error = 5.54 mmHg. The estimation o
f the mean and maximum pressure from the cannula and monitoring system was
accurate in canine liver. High pressures close to 250 mmHg were generated i
n tissues during injection.