Clinical Application And Discussion Of Mechanism Of Transthecal Digital Block In Hand

OBJECTIVE:To investigate the possible mechanism of transthecal digital block in clinical setting.METHODS:Patients with hand injuries were grouped by the method of random number table : Group 1 Whetzel modified transthecal digital block.The anesthetic was injected into the flexor sheath at a point halfway between the digital and interphalangeal joint creases in the sagittal needle and the proximal phalanx,then retreated the needle to the appropriate position and pushed the lidocaine;Group 2 separated the main body of the syringe at the joint after the completion of the injection,and indwelled the needle;Group 3 Targeted the tendon sheath to the level of the palmprint,biasing the radial or ulnar side,and completed the injection.Placed the needle,marked and recorded the deviation side;Groups 4 injection was operated in the middle knuckle of the finger,and placed the needle after injection.The pain test was performed within 5 minutes after the injection by using the VAS scoring method.A pain score of 0 indicates that the anesthesia was successful.After 5 minutes of observation after anesthesia,if the patient still feels painful and unable to undergo surgery,it means that the anesthesia has failed,and the operation will be completed with the traditional finger nerve block.The patient's age,sex,finger,injury,anesthetic onset time,and need for additional anesthesia during the operation were recorded.RESULTS:From November 2015 to December 2017,a total of 79 patients(82fingers)were enrolled in the study,with an average age of 41.1 years(median age 41,17-65).Forty-seven(59%)were male.The mean onset time of patients in Group 1 was 129.2±33.5s;Group 2 was 121.2±24.6s;in Group 3,the mean onset time on the biased side was 123.4±22.6s,and that of the contralateral side was 142.7±23.9s;and that of Group 4 was139.5± 23.0s.The onset time between test group 2 and group 1,group 4and group 1,P were 0.381 and 0.251,respectively,with no statistical significance.The data of the same test group 3 and group 1 were: biased side and group 1,P=0.508,and contralateral and group 1,P=0.135,>0.05.After the needles were removed from each group,the proportion of the anesthetic area was enlarged.No adverse effects were found after surgery.DISCUSSION:Compared to previous studies of transthecal digital block which remained at the standard of the cadaver,the results of the study of patients were more intuitive and reliable.The indwelling needles in group2,group 3,and group 4 blocked the passage of lidocaine reflow infiltration and provided a conduit for the release of fluid pressure within the tendon sheath.It was thought that the anesthetic remained only in the tendon sheath.The experimental results showed that all fingers of the groups still had anesthesia.There was no statistical difference in the onset time.It is proved that there is a kind of traffic structure between the tendon sheath and the finger vessel nerve bundles,so that the anesthetic drugs can be widely distributed to the segment of the finger vessels and nerves.This is consistent with the results of some current anatomical studies.There was no difference in the onset time between the lateral and contralateral sides of Group 3,demonstrating that even if the infiltrative anesthetic infiltrates during the first injection of a small amount of injection,the main reason for the anesthetic effect is still the effect of intrathecal anesthetics.Group 4 demonstrated that the onset of anesthesia had nothing to do with the level of injection and demonstrated the role of the traffic structure.The increase in anesthesia area after needle removal indicates that the mechanism of anesthesia anesthesia may be the result of multifactorial superposition.CONCLUSION:The anesthetic effect of transthecal digital block is reliable.A single injection can reduce the patient's pain.The reflux of anesthetic along the needle is not the main reason for the onset of ttransthecal digital block;there is a kind of traffic structure between the flexor tendon sheath and the nerve bundles,and its function makes the anesthetic can be quickly distributed in the blood vessels and nerves of the fingers,which is the main reason for rapid onset.The gain of the transthecal digital block may be the result of a multi-factor additive interaction.