Cardiorespiratory function in surgically treated thoracic scoliosis with respect to degree and apex of scoliotic curve.

We studied the relationship of deterioration of cardiorespiratory function with respect to degree and localisation of apex of spinal curvature. The study comprised 33 patients (27 females and 6 males) aged 15 (11-21) years, surgically treated for an average scoliotic angle of 72 degrees (55-129 degrees, after Cobb) which was postoperatively reduced to 32.6 degrees (13-74 degrees). The static and dynamic cardiorespiratory function parameters were tested (pre-operatively and 24 months after surgery) by spirometry and plethysmography, arterial blood gas analysis, and the exercise tolerance test. In terms of the site and apex of the thoracic curve as determined by spine X-ray, patients were divided into two groups: upper thoracic scoliosis with the apex between T5 and T8 and lower thoracic scoliosis with the apex between T9 and T11. Only upper thoracic scoliosis with Cobb angle of more than 70 degrees correlated (r = -1) with restrictive ventilation disorder (vital capacity 68%) and latent hypoxaemia (uptake O2 ml/kg/min 63%) demonstrated during the exercise tolerance test (p > 0.05). The results of the test have demonstrated that surgically obtained 54% correction of the scoliotic curve improves pulmonary function (p < 0.05). However, the improvement does not match the degree of achieved scoliotic curve correction, what means that even in surgically treated high-angled thoracic scoliosis exists an increased risk of morbidity and mortality.