Table 1. Investigation results of sensor needle insertion with two cannulation methods.

	Modified technique (n = 20)		Conventional technique (n = 20)		P value
	Intact	Castration	Intact	Castration
Needle dislodgment	0	0	3	1	–
Blood leakage	0	0	1	1	–
Total success rate (%)	100% (20/20)                       70% (14/20)				0.02

Comparisons between two groups using a Fisher's exact test.