Respiratory function in severe scoliosis before and after treatment (a review of 76 cases).

The authors carried out a study of respiratory function in seventy six patients suffering from severe scoliosis of different types; forty five idiopathic, sixteen poliemyelitic, ten congenital, and five neurofibromatosic. The age incidence was from a minimum of eleven years to a maximum of thirty three, with the average around fifteen years. The site of the deformity was predominantly dorsal (fifty cases), though there were also lumbar and dorso-lumbar types. The average angle of curvature (Cobb) before treatment was 110 degrees. Arthrodesis by the Harrington technique was carried out on all patients after correction with a Risser-type plaster in sixty nine cases, and Halo-traction in seven cases. The post operative period in plaster was about eight months. Spirometric tests were carried out before treatment, after preoperative correction, and two to three years after operation, always with the chest out of plaster. The results of these tests are expressed as percentage reductions in the maximum ventilation compared with the average normal values in the tables reported by Baldwin et al. (1948). The values obtained before commencing treatment showed that lumbar scoliosis even if very severe, never leads to severe respiratory deficits. There is no linear relationship between the severity of the curve and the respiratory deficit, though there is a general connection between them. Tests of respiratory function were carried out after corrective treatment, both before and after operation and at a two year follow up. There was an overall average improvement of 10% in the respiratory deficit, with a maximum of about 20% in a group of twenty two patients with the most severe deficit before commencing treatment. Follow-up three years after operation showed the improvement in respiratory fimction had been maintained. The authors conclude that arthrodesis by the Harrington technique does not diminish the respiratory gain achieved by pre-operative correction. On the contrary, it stabilises it and maintains it over the three year follow-up period of the present survey.