Comparison between the effects of Harrington Rod and multisegmented instrumentations in sagittal plane correction of idiopathic scoliosis

Objective: To present the changes in projected thoracic hypokyphosis and the behavior of lumbar lordosis within and below the fusion and to compare these changes between the Harrington rod (HR) and posterior multisegmented hook instrumentation. Methods: 178 patients with idiopathic scoliosis, who had undergone posterior spinal fusion with Harrington technique (106 patients) or multisegmented hook system (72 patients), were analyzed. Results: The average coronal plane correction was 37% with the Harrington technique and 54% with the multihook system. In sagittal plane correction and in thoracic kyphosis in patients treated with HR technique, the preoperative thoracic hypokyphosis became normal in 20% of cases, remained unchanged in 60% and deteriorated in 20% of cases. Normal preoperative thoracic kyphosis did not increase in any of the cases. The thoracic kyphosis in patients treated with multihook technique became normal in 66%, remained unchanged in 17% and deteriorated in 17% of cases. Normal preoperative thoracic kyphosis remained the same post-operatively in 92% and changed to kyphosis in 8% of cases. Of 38 cases with decrease in total lumbar lordosis, 33 cases showed decrease, and 5 cases remained unchanged postoperatively concerning lumbar lordosis at the fusion level. Conclusion: The effect of the multihook system to correct coronal plane deformities was markedly better than the HR system (53.8% vs. 37.9%).