| Objective:To observe the relationship between the epineurium of the supraclavicular brachial plexus and the surrounding sheath by autopsy and clinical trials,and to observe the pressure changes,anesthetic effects and anesthesia related to intrathecal injection of local anesthetics during nerve block,so as to evaluate the reasonable location of drug injection.Methods:Part I:Select two adult anti-corrosion corpses from the Department of Anatomy of Suzhou University to dissect the brachial plexus system.At least two sides of the corpse should ensure that the brachial plexus is not damaged,and their tissues have certain flexibility.After fully unlocking the membrane structure outside the supraclavicular brachial plexus,methylene blue was injected between the nerve sheath and the epineurium,and the diffusion of methylene blue around the brachial plexus was visually observed.Part ?:50 patients underwent open reduction and internal fixation of the radial fracture under the supraclavicular brachial plexus block.The ASA grade ? or ?,18 years old or older.50 patients were randomly divided into two groups,the extra-sheath group:local anesthetic injection in the outer circumference of the brachial plexus sheath;intra-sheath group:local anesthetic injection between the nerve sheath and the epineurium.Exclusion criteria:patients with contraindications to brachial plexus block before surgery(for example,obvious neck deformity),body mass index greater than 35 kg/m2,inability to communicate in language,pre-existing neurological deficits in the affected limb,allergic to local anesthetics,ultrasound images are not clear in acute systemic diseases or in acute exacerbations of systemic diseases such as chronic heart,lung,liver and kidney.Under the guidance of ultrasound,the needle tip reaches the target site,and the drug is continuously administered by the syringe pump at a delivery rate of 10 ml/min.The change of the drug solution pressure during the injection process is monitored at the tee portion connecting the syringe and the puncture needle,and the whole process is recorded.The maximum pressure value is recorded.After the injection is completed,keep the position of the puncture needle and continue to observe the change of the value on the pressure gauge.After the withdrawal of the puncture needle,the changes in the sensory movement of the blocked side of the patients were tested every lmin,and the onset time of block and the changes in muscle strength were recorded.The patients were followed up after the surgery to understand and record the duration of postoperative analgesia,the complications related to anesthesia,and the satisfaction of anesthesia.Results:Part I:Through autopsy,we observed a dense and tough fibrous membrane structure on the outer periphery of the supraclavicular brachial plexus,which extends down to the armpit,enveloping the brachial artery,the axillary vein,and the brachial plexus of the axillary approach.It is what we call the sheath.Exfoliation of the sheath reveals that the supra-clavicular brachial plexus is concentrated in the anterior aspect of the subclavian artery.The brachial plexus forms multiple branches of varying thickness.Each nerve is surrounded by a tough and elastic epineurium,there is a certain gap,surrounded by some connective tissue and fascia.When we put the puncture needle into the sheath of the supraclavicular brachial plexus,we injected methylene blue and found that the drug solution was wrapped by the sheath and formed a certain tension in the membrane.With the continuous injection of the drug solution,the drug solution was upward.Diffusion downwards,and finally some of methylene blue penetrated from the sheath.It indicates that the space in the outer sheath of the supraclavicular brachial plexus has some ductility,and the drug is not limited to the local part,even when the pressure is too large,the drug solution penetrates into the peripheral tissue through the sheath.After 10 minutes,the upper clavicle of the clavicle was dissected and the nerve was completely saturated with methylene blue.Part II:Ultrasound-guided intrathecal injection of the supraclavicular brachial plexus compared with the extra-sheath injection,the onset time of the sheath:9.4±1.3 min,the onset time of the sheath:11.8 ± 1.7 min,intrathecal The effect was faster(P<0.05).The maximum injection pressure in the sheath:7.3 ± 0.6 psi,the maximum injection pressure outside the sheath:6.8 ± 0.7 psi,the injection pressure in the sheath was slightly larger than the outer sheath(P<0.05).The duration of analgesia in the intrathecal group was 7.4±1.2h,and the duration of analgesia in the extracapsular group was 6.8±1.2h.There was no significant difference in the maintenance time between the two groups(P>0.05).In the intrathecal group:8.6±1.4,the extra-sheath group:7.9±1.9,there was no significant difference in anesthesia satisfaction between the two groups(P>0.05);1 case in the intra-sheath group showed abnormality during the block.However,there was no abnormality of limb movement after operation.1 case of intra-operative extra-sheath group had intraoperative nausea and the other patients had no anesthesia-related complications.Conclusion:The first part:Through this study,we saw that the outer circumference of the supraclavicular brachial plexus surrounds a layer of fascia(the sheath).The sheath has continuity and elasticity and permeability.The intrathecal injection of methylene blue can be evenly distributed to each nerve.The second part:find the corresponding sheath on the ultrasound image of the human body,and the injection is uniform under the sheath.The block effect is better than the extra-sheath injection.The maximum injection pressure is<8 psi,which is not enough to produce high pressure nerve damage,and no significant complications. |
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