Effect Of Paravertebral Muscle Fat Infiltration On Dosage And Effect Of Rocuronium Use In Lumbar Surgery

Objective:To investigate the effect of different degrees of fat infiltration of paravertebral muscles on dosage and effect of rocuronium use in lumbar surgery.Methods:The research method used in this study is a prospective cohort study.From December2021 to September 2022,the Second Hospital of Shanxi Medical University selected 87patients who underwent L_4-5spinal canal decompression combined with vertebral fusion surgery,including 42 males and 45 females,aged 31-65 years.The American Association of Anesthesiology（ASA）classified 22 cases as Grade I and 65 cases as Grade II.87patients underwent preoperative MR examination to measure the cross-sectional area（CSA）,functional muscle area（FMA）,and fat infiltration rate of the spine muscle and multifidus muscle（collectively referred to as paravertebral muscle）in the L_4⁵segment of the surgical area.According to the grade standard of fat infiltration,they were divided into three groups.Among them,28 patients with fat infiltration rate<30%were in the mild fat infiltration group（Group L）,and 30 patients with fat infiltration rate of 30%～50%were in the moderate fat infiltration group（Group M）,29 patients with fat infiltration rate>50%were in the severe fat infiltration group（group H）.The Drager Trident muscle relaxation monitor was used to monitor the muscle relaxation of trapezius muscle.During the maintenance of anesthesia,rocuronium was continuously pumped.The pump speed of rocuronium was adjusted according to the post-tetanic stimulation count（PTC）to maintain0<PTC≤2;rocuronium 5mg was given intermittently according to the muscle relaxation state during operation.Observation indicators:（1）Compare the clinical baseline data of three groups of patients;（2）The CSA and FMA of lumbar paravertebral muscles at L_4⁵were compared in three groups;（2）To compare the CSA and FMA of L _4⁵paravertebral muscles in the three groups;（3）To compare the total dose of rocuronium,pump time and pump speed of rocuronium during the maintenance of anesthesia in the three groups;（4）To compare the onset time,clinical efficacy,recovery index and satisfaction score of muscle relaxation in the three groups.Results:（1）There were no significant differences in sex,age,height,body mass,BMI,fat-free body mass,preoperative albumin and electrolytes among the three groups（P>0.05）.（2）There was no significant difference in CSA of L _4⁵paravertebral muscles among the three groups（P>0.05）.FMA from large to small was（35.8±4.4）cm²in L Group>（29.3±6.7）cm²in M group>（19.9±3.1）cm²in H group,the difference was statistically significant（F=73.22,P<0.05）.（3）The total dosage of rocuronium was（42.1±5.0）mg in L Group>（30.5±8.1）mg in m group>（25.5±5.4）mg in H group,the pump speed from high to low in L group was（23.7±2.8）ug·kg^-1·min^-1>M group（18.1±2.6）ug·kg^-1·min^-1>H group（16.42±2.3）ug·kg^-1·min^-1,the difference was significant（F=51.05,60.54,P<0.001）.There was no significant difference in the time of rocuronium infusion among the three groups（P>0.05）.（4）The onset time of rocuronium was（108.4±8.6）s in L Group>（102.8±10.2）s in m group>（96.9±8.2）s in H Group,the clinical efficacy was（31.0±3.1）min in group H>（27.0±3.2）min in group M>（24.0±2.5）min in group L（F=11.45,40.76,P<0.001）.There was no significant difference in rocuronium recovery index and satisfaction score of muscle relaxation between the three groups（P>0.05）.Conclusion:In lumbar surgery,the extent of fat infiltration of paraspinal muscles in the operative area has a significant effect on the dosage,onset time and clinical efficacy of rocuronium.The lower the degree of fat infiltration,the higher the dose of rocuronium needed,and the longer the onset time of rocuronium in the induction phase and the shorter the clinical efficacy in the maintenance phase.The degree of fat infiltration of paravertebral muscles may provide a reference for the individualized administration of rocuronium in patients undergoing lumbar surgery.