28 The Iowa Orthopaedic Journal ABSTRACT This paper evaluates the efficacy the Moss-Miami System instrumentation for surgical treatment of spinal deformity. Eight-five patients with AIS un- Eight-five patients with AIS un- derwent a posterior spinal fusion with using this system between 1994 and 1998. Radiographs of the spine were taken preoperatively, at discharge, one year after surgery, and at the latest follow-up (average of 2.5 year, range 2 to 6 years). All radio- graphs were assessed for curve magnitude, coronal balance, kyphosis, lordosis, junctional kyphosis, and sagittal balance. The Scoliosis Research So- ciety instrument was administered at the final follow-up. The average curve correction ranged from 53 to 65 percent. All patients showed solid fusion by final follow-up. Three patients required a second operation for complications related to their scoliosis; two patients showed a rod fracture without evidence of pseudoarthrosis or curve progression. Two transient neurological complica- tions related to the surgery were observed. SRS results were favorable with regard to function and cosmetic appearance. INTRODUCTION Hibbs is credited with first using spinal fusion as a treatment for scoliosis in 1914. 24 The introduction of in- strumentation for spinal fusion started with Harrington in 1960, 23 and consequent to this innovation, surgical treatment has evolved from the one-planar, two-dimen- sional instrumentation of Harrington to the three-planar, three-dimensional instrumentation of Cotrel-Dubousset in 1984. 12,14,15 Cotrel-Dubousset instrumentation was designed to provide segmental fixation of the spine and selective distraction and compression at different levels to improve the alignment of the spine in the coronal, sag- ittal and axial planes. The stability achieved by this sys- tem precludes the need for post-operative immobilization in the majority of cases. 1,31,32,45,47 Nevertheless, despite reports of satisfactory results with regard to fusion, per- centage correction, and minimal complications, problems have been reported with posterior systems, including loss of correction in the lumbar spine, hypokyphosis of the thoracic spine and the presence of a thoracolumbar kyphosis below the level of instrumentation. 5,9,30,42,49 The Moss-Miami System instrumentation (DePuy, Warsaw, IN) was introduced in 1994, and shortly there- after we began using the system for all patients with adolescent idiopathic scoliosis. Advantages of this system include a lower profile, smaller dimensions, top-opening hooks simplifying rod placement, and the ability to use various hooks or screws in the lumbar spine. The purpose of this study is to describe short-term radiographic, clinical and patient-oriented outcomes after fusion and instrumentation with the Moss-Miami System for the treatment of adolescent idiopathic scoliosis. MATERIALS AND METHODS Patient Selection The indications for surgical treatment of adolescent idiopathic scoliosis included a progressive cur ve over 40 degrees in skeletally immature patients or a progressive curve measuring greater than 50 degrees or a painful curve in skeletally mature patients. All surgeries were performed using by the senior author using Moss-Miami instrumentation. Those who underwent surgery at or before the age of 18, with a minimum of two-year fol- low-up were included. Radiographic Analysis Standing posteroanterior, lateral, and anteroposterior with lateral bending radiographs were taken of all pa- tients prior to surger y; oblique films were taken between six to eight months post-operatively, and posteroanterior films were taken yearly. We do not routinely obtain lateral films on post-operative patients, and these were available for twenty-three of the patients at the final follow-up. POSTERIOR SPINE FUSION WITH MOSS-MIAMI INSTRUMENTATION FOR ADOLESCENT IDIOPATHIC SCOLIOSIS: RADIOGRAPHIC, CLINICAL AND PATIENT-CENTERED OUTCOMES Fernando De Maio, MD; Lori A. Dolan, PhD; Vincenzo De Luna, MD; and Stuart L. Weinstein, MD This work was supported by the Sovena Foundation. Study conducted at the University of Iowa Hospitals and Clinics, Iowa City, Iowa Corresponding Author: Stuart L. Weinstein, MD Department of Orthopaedic Surgery 01026 JPP University of Iowa Hospitals and Clinics 200 Hawkins Drive Iowa City, Iowa 52242 stuart-weinstein@uiowa.edu