Preliminary Study Of The Effect Of Nuss Procedure On Respiratory Function In Pectus Excavatum Model Rats

Objective: To investigate the changes of respiratory function after the formation of pectus excavatum in rats and the effect of the imitated Nuss procedure on respiratory function by measuring the chest volume,respiratory mechanics indexes,pulmonary function and pulmonary volume before and after the imitated Nuss procedure.Methods: Divided 128 4-week-old SD rats into control group(n = 48),PE group(n = 48)and the imitated Nuss group(n = 32)randomly.Cut off the 5th,6th and 7th pairs of costal cartilages next to the sternum to create pectus excavatum models in the PE group and the imitated Nuss group.And used the Z-shaped steel needle to carry out the imitated Nuss procedure in the imitated Nuss group 6 weeks after model making.And then took out the internal fixation steel needle 4 weeks after the imitated Nuss procedure.Measured the chest volume,respiratory mechanics indexes,pulmonary function and pulmonary volume of rats at6 weeks after model making,4 weeks after the imitated Nuss procedure and 4 weeks after the internal fixation steel needle removal and compare the indexes among groups.Results:(1)Six weeks after model making,compared with the control group,the chest volume of PE group(6.15±0.46)was significantly reduced than the control group(8.24±0.63)(P<0.05).The transverse diameter of the thoracic cavity of PE group was not significantly different with the control group(P>0.05).The anteroposterior diameter of the thoracic cavity of PE group was significantly shorter than that of the control group(P<0.05).The Haller index of PE group(1.8±0.1)was significantly higher than that of the control group(1.36±0.1)(P<0.05).The Ri and Re of PE group was significantly higher than that of the control group(P<0.05).The Cdyn of PE group was significantly lower than that of the control group(P<0.05).The FVC,FEV0.2 and FEF50 in PE group was significantly lower than that of the control group(P<0.05).The FEV0.2/FVC in PE group was not significantly different from that of the control group(P>0.05).The pulmonary volume of PE group(9.11±0.88)was significantly lower than that of the control group(7.77± 1.01)(P<0.05).(2)Four weeks after the imitated Nuss procedure.(1)Compared with PE group,the chest volume in PE group(7.2±1.08)was significantly lower than that of the control group(9.72±0.52)(P < 0.05).The transverse diameter of the thoracic cavity in PE group was not significantly different from that of the control group(P >0.05).The anteroposterior diameter of the thoracic cavity in PE group was significantly lower than that of the control group(P<0.05).The Haller index in PE group(2.17±0.14)was significantly higher than that of the control group(1.31±0.06)(P<0.01).The Ri and Re of the PE group was significantly higher than that of the control group(P<0.05).The Cdyn of the PE group was significantly lower than that of the control group(P<0.05).The FVC,FEV0.2and FEF50 of the PE Group was significantly lower than that of the control group(P<0.05).The FEV0.2/FVC of the PE group was not significantly different from that of the control group(P>0.05).The pulmonary volume of the PE group(6.78±1.39)was significantly lower than that of the control group(9.11±0.88)(P<0.05).(2)Compared with the control group,the chest volume(8.58±0.73)of the imitated Nuss group was significantly decreased(P<0.05).The transverse diameter and anteroposterior diameter of the thoracic cavity was significantly decreased(P<0.05).The Haller index(1.4 ±0.08)was not significantly different from that of the control group(1.31±0.06)(P>0.05).The Ri and Re of the imitated Nuss group were significantly increased(P<0.05).The Cdyn of the imitated Nuss group was significantly decreased(P<0.01).The FVC,FEV0.2 and FEF50 of the imitated Nuss group were significantly decreased(P<0.05).The FEV0.2/FVC had no significant difference compared with the control group.The pulmonary volume of the imitated Nuss group(8.04±0.99)was significantly decreased compared with the control group(9.11±0.88)(P<0.05).(3)Compared with the PE group,the chest volume(8.58±0.73)of the imitated Nuss group was significantly larger than that of the PE group(7.2±1.08)(P<0.05).The transverse diameter of the thoracic cavity of the imitated Nuss group was significantly smaller than that of the PE group(P<0.05).The anteroposterior diameter of the thoracic cavity was significantly larger than that of the PE group(P<0.05).The Haller index of the imitated Nuss group(1.4±0.08)was significantly lower than that of the PE group(2.17±0.14)(P<0.05).The Ri,Re and Cdyn had no significant difference between the two groups.There was no significant difference in FVC,FEV0.2,FEV0.2/FVC and FEF50 between PE group and the imitated Nuss group(P>0.05).The pulmonary volume of the imitated Nuss group(8.04±0.99)was significantly larger than that of the PE group(6.78±1.39)(P<0.05).(3)Four weeks after removal of the internal fixation.(1)Compared with the control group,the chest volume in PE group(8.2±2.15)was significantly decreased(P<0.05).The transverse diameter of the thoracic cavity of the PE group was significantly decreased(P<0.05).The anteroposterior diameter of the thoracic cavity of the PE group was significantly decreased(P<0.05).The Haller index of the PE group(2.44±0.2)was significantly increased(P<0.05).The Ri and Re of the PE group were significantly increased(P<0.05).The Cdyn of the PE group was significantly lower than that of the control group(P<0.05).The FVC,FEV0.2 and FEF50 were significantly lower than that of the control group(P<0.05).The FEV0.2/FVC had no significant difference between the two groups(P>0.05).The pulmonary volume of the PE group(8.13±1.15)was significantly lower than that of the control group(11.29±1.72)(P<0.05).(2)Compared with the control group,the chest volume of the imitated Nuss group(10.83±1.21)was significantly lower than that of the control group(12.7±1.14)(P<0.05).The transverse diameter of the chest of the imitated Nuss group was significantly lower than that of the control group(P<0.05).The anteroposterior diameter of the thoracic cavity of the imitated Nuss group was significantly lower than that of the control group(P<0.05).The Haller index of the imitated Nuss group(1.47±0.09)was not significantly different from that of the control group(1.36±0.06)(P>0.05).The Ri and Re of the imitated Nuss group were significantly higher than that of the control group(P<0.05).The Cdyn of the imitated Nuss group was significantly decreased than that of the control group(P<0.05).The FVC,FEV0.2and FEF50 of the imitated Nuss group were significantly decreased than those of the control group(P<0.05).The FEV0.2/FVC had no significant difference between the two groups.The pulmonary volume of the imitated Nuss group(9.93±1.22)was significantly decreased than that of the control group(11.29±1.72)(P<0.05).(3)Compared with PE group,the chest volume in the imitated Nuss group(10.83±1.21)was significantly increased(P<0.05).The transverse diameter of the imitated Nuss group was significantly increased than that of the PE group(P<0.05).The anteroposterior diameter of the thoracic cavity of the imitated Nuss group was significantly increased than that of the PE group(P<0.05).The Haller index of the imitated Nuss group(1.47±0.09)was significantly lower than that of the PE group(P<0.05).The Ri and Re of the imitated Nuss group were significantly decreased(P<0.05).The Cdyn of the imitated Nuss group was significantly higher than that of the PE group(P<0.05).The FVC,FEV0.2 and FEF50 of the imitated Nuss group were significantly increased compared with the PE group(P<0.05).The difference of the FEV0.2/FVC had no statistical significance between the two groups(P>0.05).The pulmonary volume of the imitated Nuss group(9.93±1.22)was significantly increased compared with the PE group(8.13±1.15)(P<0.05).Conclusion:1.After the formation of pectus excavatum,the chest volume,pulmonary volume and respiratory function of rats were affected.The chest volume,pulmonary volume and respiratory function of rats were decreased compared with normal rats.2.As the pectus excavatum deformity was corrected by the imitated Nuss procedure,the chest volume and pulmonary volume increased,and the respiratory function improved at the same time which involved the decreased inspiratory and expiratory resistance.3.The indwelling of the internal fixation needle reduced the compliance of the chest wall and thus affected the improvement of the respiratory function.But the compliance of the chest wall increased with the removal of the internal fixation,and the respiratory function then improved near the normal level.