Background: Although many techniques for the surgical treatment of scoliosis have been described, we are not aware of any randomized trials that have compared implant systems. The relationship between surgeons' preferences for implants and patient outcomes is unknown. The purpose of the present study was to compare quality of life and curve correction associated with use of the Moss Miami system and the Universal Spine System for spinal fusion in patients with adolescent idiopathic scoliosis.
Methods: The present study was a double-blind, randomized clinical trial. All adolescent patients with idiopathic scoliosis who were scheduled for posterior instrumentation and arthrodesis with or without anterior release were screened for eligibility. Patients were randomly allocated to treatment with either the Moss Miami system or the Universal Spine System. The primary outcome measure for this trial was Quality of Life Profile for Spinal Disorders.
Results: Of the 129 subjects who were enrolled in the trial, sixty (95%) of sixty-three from the Universal Spine System group and sixty (91%) of sixty-six from the Moss Miami group were included in the final analysis. Two years postoperatively, the total Quality of Life score did not differ by the clinically important value of 5.5 between the two groups (difference, 1.07; 95% confidence interval, -3.67 to 5.82; p = 0.66). The percentage of Cobb angle correction was not significantly different for thoracic curves (55.1% +/- 18.3% for the Moss Miami system group, compared with 54.1% +/- 18.7% for the Universal Spine System group) (difference, -1%; 95% confidence interval, -7% to 5%; p = 0.77) or lumbar curves (45.4% +/- 24.6% for the Moss Miami system group, compared with 41.9% +/- 26.8% for the Universal Spine System group) (difference, -4%; 95% confidence interval, -16% to 11%; p = 0.57). Although surgeons were more satisfied with the Universal Spine System (difference, 42%; 95% confidence interval, 29% to 55%; p < 0.0001), satisfaction ratings were not related to any surgical outcomes.
Conclusions: The Moss Miami system and the Universal Spine Systems provided similar quality of life and curve correction. Surgeon preference may be an unreliable means of selecting implants from the patient outcomes perspective.