Table 1.

Technical differences in ultrasound-guided obturator nerve block techniques.

	Soong et al. [38] Fujiwara et al. [39] Sinha et al. [30]	Akkaya et al. [35]	Anagnostopoulou et al. [17] Taha [23]	Lin et al. [42]	Yoshida et al. [31]
Ultrasound probe orientation	In-plane	In-plane	Out-of-plane	In-plane	In-plane
Transducer position	Inguinal crease	Pubic region	Inguinal crease	Inguinal crease	Medial thigh
Transducer tilt	Not required	Not required	Required	Required	Not required
Needle-ultrasound beam angle	Small (posterior branch)	Small	NA	Small	Large
Nerve stimulation guidance	Recommended	Recommended	Not needed	Not needed	Not needed
Patient position	Supine	Supine	Supine	Supine	Lithotomy

NA, not applicable.