The Comparison Of Double And Triple Hemisection On The Slide Lengthening Of Tendon

BackgroundTendon lengthening is a surgical method for the treatment of limb contracture after spastic paralysis.Physical therapy commonly used to treat contracture includes acupuncture,massage,orthosis,oral or injection drugs and other methods.In recent years,the newly proposed cervical nerve root transfer has also achieved effective results.When these methods are ineffective in the treatment of spastic paralysis,tendon lengthening is often used.Tendon lengthening can reduce the tension of spastic muscles by changing the tendon length and provide them with sufficient range of motion.Tendon lengthening includes segmental lengthening,sliding lengthening and Z-shaped lengthening.Due to the small incision and short operation time,sliding lengthening can reduce the incidence of incision complications,and this operation can maintain the continuity of tendon collagen fibers to a certain extent.Therefore,its postoperative tendon biomechanical effect is the best.However,there is no consensus on the optimal number of tendon hemisection planes and the spacing between incisions.Therefore,this study intends to explore the potential of tendon elongation after double and triple hemisection sliding lengthening and the comparison of biomechanical effects of tendons with different spacing between incisions.MethodsForty eight deep flexor tendons of pig toe were divided into double hemisection group,three hemisection group（group A and group B）and control group（group C,n= 6）.The double half cut group was half cut in the contralateral ipsilateral mode,and the three half cut group was half cut in the contralateral ipsilateral contralateral mode.The three hemisection group（group B,n = 18）was divided into three subgroups with the spacing between hemisections of 0.5cm,1cm and 2cm respectively.The distance between half sections of the double half section group（group A,n = 24）corresponds to the distance between half sections of group B and the distance between the farthest half sections.It is divided into two subgroups A1 and A2.The distance between half sections is 0.5cm,1cm and 2cm（group A1）and 1cm,2cm and 4cm（group A2）respectively.Six tendons were randomly selected from each subgroups.Since two subgroups in group A1 coincided with two subgroups in group A2,the experiment was carried out according to only one group.The tendons in the control group were not treated.After that,the treated tendon was fixed on the universal testing machine for tensile test,and the maximum failure load and elongation were measured for biomechanical evaluation.At the same time,it is necessary to record the whole process through video equipment,and put the video into professional video analysis software for motion analysis,measure and observe the relationship between tendon elongation and its own shape variables,and explore the elongation law of tendons in each group.ResultsIn the blank control group（group C）,the intact tendon elongated evenly during constant speed stretching.In the double hemisection group（group A）,the deformation of the tendon occurred symmetrically centered on the central point of the tendon until relative slip occurred.In the three hemisection group（group B）,the tendon was deformed symmetrically centered on the central point of the tendon at the beginning of tension,until there was a relative slip between the central hemisection and one of the two ends.The failure load of tendons treated with double or triple hemisection was significantly lower than that of intact tendons（p < 0.05）.When the distance between half sections is less than 1 cm,there is no significant difference between the elongation of tendon after double or three half sections（group A or B）and that of intact tendon（group C）.When the distance between half sections reached 1cm,2cm and 4cm,the elongation of double or three half cut tendons（group A and group B）was significantly higher than that of intact tendons（group C,p < 0.05）.The length of deformation of intact tendon（group C）was significantly higher than that of tendon in groups A and B（p < 0.05）.In the double hemisection group（group A）,when the spacing between hemisections reached 2cm,the failure load of tendon increased significantly（p < 0.05）,but it was significantly lower than that when the spacing between hemisections was 4cm.In group B,there were significant differences in the failure load of tendons with different half section spacing（p < 0.05）.When the distance between half sections was equal,there was no significant difference in tendon elongation between double half section and three half section.When the distance between the half sections was 0.5cm and 1cm,the failure load of the three half cut tendon was significantly lower than that of the double half cut tendon.When the distance between the distal half sections was the same,the elongation and failure load of the tendon treated with three half sections were significantly lower than those treated with two half sections（p < 0.05）.ConclusionWhen the spacing between the half sections is the same,the lengthening ability of the double half section treated tendon is similar to that of the three half sections treated tendon.However,when the spacing between the distal half sections of the tendon is the same,the lengthening ability of the double half section treated tendon is greater,but the initial driving force of starting lengthening may be greater,resulting in increased difficulty in operation.The selection of surgical methods can be comprehensively considered according to the required elongation,and the elongation can also be estimated preoperatively according to the spacing between incisions.