Application of the saphenous nerve emerging site through the adductor canal in ultrasound-guided adductor canal block / 临床麻醉学杂志

ABSTRACT

Objective To study clinical data retrospectively and demonstrate the optimal injection site of adductor canal block by performing a cadaveric study.Methods Clinical partclinical data from 19 patients,11 males and 8 females,aged 21 85 years,ASA physical status Ⅰ-Ⅲ,who received ultrasound guided adductor canal block were retrospectively collected.Among whom 9 received a mid-distance injection of 10 ml of 0.5％ ropivacaine and 10 received an injection of the same medication at the outlet of adductor canal.The primary endpoint was complete absence of cold sensation to ice cube on the medial side of calf at 30 minutes and 24 hours after injection.Cadaveric part40 lower limbs,20 males and 20 females,were finally analyzed in the study.The distances from the anterior superior iliac spine (ASIS) to the medial tibial condyle,from ASIS to the entrance of the adductor canal,from ASIS to the exit of the canal (adductor tendinous opening),from ASIS to the site where sa phenous nerve emerges through the aponeurotic covering were measured respectively.The length of adductor canal,the relative location of adductor canal and the site where saphenous nerve pierces in the lower limbs were calculated.Results Clinical partall 19 cases were successfully recorded with complete absence of cold sensation at 30 minutes after injection of local anesthetic and complete sensory recovery at 24 hours after injection.Cadaveric partin all specimens,saphenous nerve enters adductor canal and coursed down until emerging at very close to the distal end of the canal with the saphenous branch of descending genicular artery.The length of the adductor canal was (10.0±2.1) cm.The entrance and the exit of adductor canal and the emerging site of the saphenous nerve located along the (54.7±3.0) ％,(76.0％±3.8) ％ and (74.1±3.2) ％ of sartorius muscle,respectively.Conclusion Performing ultrasound-guided adductor canal block at either the outlet of adductor canal or mid-distance of thigh can achieve comparable blockade of saphenous nerve.Cadaveric study implicated that the optimal injection site for adductor canal block should be the lower one-third of sartorius muscle.Ultrasound-guided injection of local anesthetics next to the descending genicular artery may possibly become a promising new method of saphenous nerve block.