Electrical resistance and current leakage of appliances for transurethral resection.

Urethral stricture following transurethral resection of the prostate (TUR-P) is closely related to the electrical resistance and current leakage of appliances. Electrical resistance and leakage were therefore investigated in 7 old bipolar loops, 3 new bipolar loops (1, 2 and 3) used for TUR-P, 2 new bipolar loops (4 and 5) for TUR-bladder tumor (TUR-Bt), and 4 new monopolar loops (6 through 9) for TUR-P. Two of the 7 old bipolar loops were found to be positive and 5 negative for current leakage. The 2 positive loops had resistances of 4.4 and 17 ohm . Before use, the electrical resistance of the 5 new bipolar loops (1 to 5) ranged from 0.5 to 0.6 ohm. The resistance of loop 1 was less than 5 ohm after the sixth use, and that of loop 3 was 2.8 ohm after the fifth use. By contrast, loop 2 exhibited resistance of 115 ohm after the third use. The average operation time for loops 1, 2 and 3 were 66, 64 and 62 minutes. Loop 4 showed resistance of 14 ohm after the third use, and loop 5 1 ohm even after the sixth use. Furthermore, none of the 5 loops showed current leakage. On the other hand, all 4 monopolar loops (6 through 9) exhibited current leakage after the first use, and showed relatively high electrical resistance. These findings demonstrate the necessity of timely replacement of bipolar loops and the exchange of monopolar loops after the first use.