Abstract
In Japan, the most frequently used needles for sclerotherapy for esophageal varices are commercially available from five manufacturers (Olympus, Argyle, Sumitomo B, Medical, Top and Microvasive). We developed new injection needles for sclerotherapy with Microvasive co. and compared the following basic features of 23G needles for this purpose (Microvasive 25G needles were also included in the study) : (1) dead space of needle, (2) resistance during insertion, (3) aspiration capacity (the time required for aspirating 100 cc water at 100 mmHg when the needle was inserted via the forceps entrance of an Olympus GIF-Q20 endoscope). The dead space greatly differed between needles (from 0.47 cc to 1.4 cc), suggesting that the dose levels of sclerosing agents need to be decided taking into account the dead space of each needle. The resistance during insertion of Microvasive 23G needle and the Argyle 23G needle was significantly lower than the needles of the other manufacturers. The Microvasive 25G needle could be inserted with less resistance than the 23G needles of the other manufacturers. The aspiration capacity of the Microvasive 23G and 25G needles was superior (30 seconds) than the other needles whose aspiration capacity ranged form 30 to 42 seconds (117 seconds for the Argyle needle), although there was not significant difference except the Argyle needles. These results suggest that the Microvasive needles for sclerotherapy are useful to any other needle of this kind commercially available in Japan.
