The effect of the rib deformity on the pulmonary dysfunction in moderate congenital scoliosis

English Keywords:Congenital scoliosis  Rib deformity  Pulmonary function

English Abstract:

  【Abstract】 Objectives: To investigate the effects of different types of rib deformity associated with moderate congenital scoliosis on the pulmonary dysfunction. Methods: A total of 108 adolescent patients (49 males and 59 females, mean age 13.5±2.1 years) with moderate thoracic CS (thoracic cobb angle 40°-70°) in our hospital from January 2008 to December 2016 was included in the present study. They were divided into three groups according to the type and range of rib deformity. CS patients without any rib deformity were classified into the control group. The simple deformity group consisted of patients with localized fusion, bifurcation of 2-3 ribs or increased or decreased 1 or 2 ribs. The complex deformity group was defined as patients with extensive fusion, bifurcation of ribs or combined with thechest wall defect. The radiographic parameters before surgery were recorded, including cobb angle, thoracic kyphosis, the number of vertebrae involved, the thoracic height(the vertical height between the center of T1 and T12), the thoracic transverse diameter(the horizontal distance between bilateral costal margins at the apex level). All of these patients were also evaluated by a standard test of pulmonary function, including vital capacity(VC), forced expiratory volume in the first second(FEV1), maximum ventilation volume(MVV), the percentage of these values to the predicted value and FEV1/FVC value. The difference of radiographic parameters and pulmonary function data in each group were analyzed. Mean while, the degree and pattern of pulmonary dysfunction were analyzed by using the chi-square test. Results: There was no difference of radiographic parameters among the three groups(P>0.05). The control group and simple deformity group had similar pulmonary function on the basis of different pulmonary parameters [VC: (81.88±11.11)% vs (78.22±8.49)%, P>0.05; FVC%: (81.66±9.72)% vs (78.35±6.74)%, P>0.05; FEV1: (79.50±10.18)% vs (75.73±8.44)%, P>0.05; MVV: (79.10±12.48)% vs (75.04±7.21)%, P>0.05]. The complex deformity group was proved to have worse pulmonary function compared with the control group [VC: (64.68±10.00)% vs (78.22±8.49)%, P=0.012; FVC: (64.61±10.57)% vs (78.35±6.74)%, P<0.001; FEV1: (59.57±10.16)% vs (75.73±8.44)%, P<0.001; MVV: (62.82±12.02)% vs (75.04±7.21)%, P=0.014]. The degree of pulmonary dysfunction in the control group and the simple deformity group was similar, mainly consisting of mild and moderate pulmonary dysfunction patients (χ2=1.314, P=0.532). In the complex deformity group, moderate and severe pulmonary dysfunction was the most common(χ2=40.1, P<0.001). The main type of pulmonary dysfunction in the three groups of CS patients was mixed pulmonary dysfunction(χ2=6.4, P=0.202). Conclusions: In patients with moderate thoracic CS, the simple rib deformation has little effect on the pulmonary function. Compared to the control group, CS patients with complex rib deformity are more likely to compromise pulmonary dysfunction, a great majority of whom suffer from moderate or severe pulmonary dysfunction. And the pattern of pulmonary dysfunction is similar among the three groups.