Surgical treatment of poliomyelitic scoliosis.

Between 1968 and 1973 forty nine patients suffering from poliomyelitic scoliosis were treated surgically at the Rizzoli Institute. They were due to asymmetrical paralysis and contracture in the muscles of the trunk and limbs. Associated pathological conditions were found, such as pelvic obliquity, and vascular and trophic changes due to ganglionic lesions. The differing incidence and combination of these factors gave rise to various clinical types of spinal deformity. The average severity of curve was 39 degrees, the localisation was predominantly central, the average extent was ten vertebrae, and there was a marked predominance of right convexity (twenty nine out of thirty six). The rate of progression was maximum during puberty and almost negligible after bony maturity. It was greater in males and was unfavourably affected by the severity and asymmetrical distribution of the paralysis, by the early appearance of the disease, by high localisation of the deformity, and by the erect posture in patients who were ambulant. The most frequent visceral complications were in the respiratory system (ten patients with a deficit over 50%), followed by cardiac changes. Surgical treatment was adopted in patients with progressive curves over 60 degrees, because of the inevitable deterioration in their general condition and the tendency of the deformity to become fixed. Pre-operative correction by Halo-traction results (52% correction) than Risser plasters (38%). Posterior arthrodesis by Harrington's method was carried out in all the more recent cases (forty four). Post-operative plaster was maintained for eight months and then replaced by an orthopaedic corset. At bony maturity there was an averaged improvement of 35% in the angle of curvature, and an average improvement of 6% in vital capacity. The best corrections were obtained in patients under fourteen (42%), in dorso-lumbar scoliosis (40%) and in patients with curves above 100 degrees (38%). There was an average increase in height of 9.1 cms and a reduction in the gibbus of 3.4 cms. The complications included one traumatic pneumothorax, eight pseudarthroses, and breakage of the distraction rod in two cases resulting in complete relapse of the deformity. In six cases the upper hooks became loos and there were two cases of postoperative staphylococcal infection. In the distally sited curves our present policy is towards combining posterior arthrodesis with Dwyer's anterior interbody fusion.