Relationship Between The Effect Of Anterior Lumbar Plexus Block Via Suprainguinal Ligament Approach And Body Index Mass In Elderly Patients

Objective:To observe the effect of ultrasound-guided anterior lumbar plexus block via superior inguinal ligament approach in elderly patients with different body mass index(BMI).Methods:There were 125 cases with femoral fracture scheduled for proximal femoral nail antirotation internal fixation,involving 67 males and 58 females,aged from 75-85 years,falling into ASA physical status ofⅡ～Ⅲ.According to BMI,they were divided into three groups,including group T(BMI15-18.5kg/m~2),group N(BMI18.5-23.9kg/m~2)and group F(BMI24-39.9kg/m~2).Patients in these three groups underwent anterior lumbar plexus block via superior inguinal ligament approach by the injection of 0.33%ropivacaine 40ml under the guidance of ultrasound.The diffusion of local anesthetic to the femoral nerve(FN),lateral femoral cutaneous nerve(LFCN)and obturator nerve(ON)was compared at 10min(T1),20min(T2)and 30min(T3)after nerve block.The block effect of FN,LFCN and ON were compared at T1,T2 and T3.The postoperative adverse reactions were compared as well.Results:There were no statistically significant differences among the three groups in the local anesthetic diffusion range and block effect in FN region at T1,T2 and T3.There were no significant differences in the local anesthetic diffusion range and block effect among the three groups at T1 and T2 in LFCN region,and the local anesthetic diffusion range and block effect in group F were significantly higher than that of group T at T3(P<0.05).There was no statistically significant difference in the local anesthetic diffusion range among the three groups at T1 and T2 in ON region,but the sensory block effect of group F at T2 was better than that of group T,and the local anesthetic diffusion range and sensory block effect of group F at T3 were significantly higher than that of group T and group N(P<0.05).There was no significant difference in the incidence of adverse reactions among the three groups.Conclusion:In elderly patients with BMI>24kg/m~2,local anesthetic diffusion rate is faster and the range is wider compared with those with BMI<24kg/m~2during anterior lumbar plexus block via superior inguinal ligament approach guided by ultrasound.And the block effect of ON and LFCN is better.