| Objective:A new low-profile growth induction system model and a dual growing rod system model with young pigs were constructed.The effects of the two systems on the thoracic and lung development of young pigs are compared with imaging and histology,and compare the difference between the operation time,the amount of surgical bleeding and the infection rate of the two systems during the experiment which provides a theoretieal basis for further research and clinical application.Methods:1.18 6-week-old pigs were randomly divided into group A,group B and group C.Group A was new low-profile gro,Arth-inducing system group,the fish-eye nails were implanted on bilateral pedicle of vertebral arch of T5-T6 and T15-LI.and bilateral pedicle of vertebral arch of T10-T11 were implanted into the universal compression double ear nails,and the titanium rod were implanted through the muscle gap passage,so that the titanium rod can slide in the fish-eye nail.Group B was dual growing rod group,traditional pedicle screws were implanted on bilateral pedicle of vertebral arch of T5-T6 and T15-L1,T10-T11 were implanted into the domino connector,and the titanium rod were implanted through the muscle gap passage,lock the rod and the spreader at the domino connector,operation to expand the titanium rod was performed once 3 weeks.Group C was the blank control group,only tissue exfoliation was performed on Bilateral of T5-T6,T10-T11 and T15-L1 and the articular processes were exposed,and pedicle screws were not implanted.2.Group A,Group B and Group C young pigs were examined by X-ray and CT at the anteroposterior and lateral positions of the spinal column respectively after operation and 3 months after operation to observe the internal fixation loss of the experimental young pigs’ spinal column,the presence or absence of nail pulling,nail breaking and rod breaking,etc.The.sliding distance of titanium rods at the head and tail ends of group A and the actual expending distance of group B were measured,and the spine length,thoracic longitudinal diameter,thoracic transverse diameter,lung volume and other data of experimental intervention segments T5-L1 in each group were measured.To analyze the correlation between thoracic length and lung volume 3 months after operation.After the animals were killed by bloodletting method at 3 months after operation,the lungs were taken by thoracotomy.All the lungs were ligated at the same level above the bifurcation of bronchi and separated from the trachea.Blood on the surface of the lungs was sucked by filter paper.The wet weight(g)of the lungs was obtained by weighing the pig lungs with an electronic balance.After weighing was completed,the lung tissues of the pig’s two lung cusps,heart leaves and diaphragm leaves were taken respectively.After the specimens were fixed,each lung tissue was continuously sectioned.After HE staining was carried out on every 5 slices,the lung tissues were taken under the light microscope 40 times visual field.Each slice is divided into four quadrants,upper,lower,left and right.One fi eld of view is randomly selected for each quadrant.The field of view without blood vessels,bronchi and acini is selected as far as possible.lmageJ 1.52a is applied to fill the alveolar cavity with color filling method,and the alveolar cavity flour density ratio(alveolar cavity area/unit area of field of view*100%)of this field of view is obtained.Results:1.There was no significant difference in T5-L1 spine lengti,thoracic transverse diameter,longitudinal diameter and lung volume between group A,group B and group C(P>0.05).2.The amount of surgical bleeding was 54.17±4.92ml in group A,96.67±5.16ml in group B and 19.17±3.76ml;in group C;the operative time was 130.83±13.19min in group A,186.67±32.50min:in group B,and 24.167±8.61min in group C.The operative bleeding volume and operative time in group B were significantly higher than those in group A and group C,with statistical difference between the two groups(p<0.05).The operative infection rate in group B was 4%,while there was no infection in group A and group C.3.The sliding distance was 7.24±0.26cm in group a and 7.13±0.11 cm in group B three months after operation.There was no statistical difference between the two groups(p>0.05).4.There was no statistical difference in the length of T5-L1 spinal column among group A,group B and group C after operation.The length of T5-L1 spinal column increased significantly in March after operation compared with before,among which group C increased by 10.55±0.41cm,group A new low-profile growth-inducing system group increased by 7.56±1.30cm,group B dual growing rod system increased by 7.21±1.63cm,but there was no statistical difference between group A and group B(P>0.05).5.There was no statistical difference in thoracic longitudinal diameter between group A,group B and group C after operation in 3 months after operation,thoracic longitudinal diameter of group A increased by 10.3 5±1.55cm,that of group B increased by 10.28±1.36cm,that of group C increased by 14.14±0.99cm,and that of group A and group B achieved similar thoracic longitudinal diameter growth degree.There was no statistical difference in the results between the two groups(P<0.05).There was no statistical difference in thoracic transverse diameter between group A,group B and group C after operation.In 3 months after operation,thoracic ransverse diameter in group A increased by 13.89±1.48cm,thoracic longitudinal diameter in group B increased by 14.23±1.55cm,thoracic longitudinal diameter in group C increased by 14.40±1.52cm.Similar thoracic transverse diameter growth degree was obtained among group A,group B and group C,and there was no statistical difference in the results among the three groups(P>0.05).6.There was no statistical difference in CT lung volume between group A,group B and group C after operation.In 3 months after operation,lung volume in group a increased 492.60±59.44ml,lung volume in group B increased 487.16±75.22ml,lung volume in group C increased 608.02±83.96ml.Similar lung volume growth was achieved between group A and group B,and there was no statistical difference in the results between the two groups(P>0.05).7.Linear regression analysis was carried out on the results of thoracic longitudinal diameter(T1-T15 spine length)and CT lung volume in 3 months after operation in 3 groups of experimental pigs.The result was R=0.84,P<0.0001.8.The results of lung wet weight 3 months after operation showed that the lung wet weight in group A was 285.67±16.66 g,that in group B was 289.33±3.38 g,and that in group C was 330.33± 11.62g.There was no significant difference in lung wet weight between group A and group B(P>0.05).Three months after the operation,the alveolar flour density ratio showed that the alveolar flour density ratio in group A was 50.28±4.19%,the alveolar flour density ratio in group B was 52.39±1.98%,and the alveolar flour density ratio in group C was 53.37±2.19%.Flour density ratio of pulmonary heart lobe alveoli in group A is 52.89±2.79%,flour density ratio of pulmonary heart lobe alveoli in group B is 55.20±3.53%,and flour density ratio of pulmonary heart lobe alveoli in group C is 57.10±3.45%;the density ratio of alveolar flour in group A is 63.05±3.47%,the density ratio of alveolar flour in group B is 62.36±3.08%,and the density ratio of alveolar flour in group C is 65.22±2.36%.There was no significant difference in lung wet weight among group A,group B and group C(P>0.05).Conclusions:1.The new low-profile growth-inducing system has significantly increased the T5-L1 spine length,thoracic longitudinal diameter,thoracic transverse diameter and lung volume of young pigs.The growth rate is similar to that of the dual growing rod system,but the number of operations,the operation time,the amount of surgical bleeding,and the infection rate were significantly less than dual growing rod system.2.There is a good correlation between the length of the chest longitudinal diameter of the young pig and the lung volume value.3.The low-profile growth-inducing system and the dual growing rod system have certain effects on the initial development of lung volume,but there is no change in the development of lung tissue structure. |
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