Clinical value of routine preoperative magnetic resonance imaging in adolescent idiopathic scoliosis - A prospective study of three hundred and twenty-seven patients

Background: The prevalence of intraspinal pathology associated with scolios is has been reported to be as high as 26% in some series(1), and, on the ba sis of this finding, preoperative magnetic resonance imaging is used in the screening of patients with adolescent idiopathic scoliosis. However, this practice continues to be highly controversial. In order to better resolve t his issue, we performed what we believe to be the largest prospective study to evaluate the need for preoperative magnetic resonance imaging in patien ts with adolescent idiopathic scoliosis requiring arthrodesis of the spine. Methods: A total of 327 consecutive patients with adolescent idiopathic sco liosis were evaluated between December 1991 and March 1999. All patients in the study presented with an adolescent idiopathic scoliosis curve pattern and had a complete physical and neurologic examination. Magnetic resonance imaging of the brain and the spinal cord were performed as part of their pr eoperative work-up. Results: Seven patients had an abnormality noted on magnetic resonance imag ing. These abnormalities included a spinal cord syrinx in two patients (0.6 %) and an Arnold-Chiari type-I malformation in four (1.2%). One patient had an abnormal fatty infiltration of the tenth thoracic vertebral body. No pa tient required neurosurgical intervention or additional work-up. All patien ts who underwent spinal arthrodesis with segmental instrumentation tolerate d the surgery without any immediate or delayed neurologic sequelae. Conclusions: The fact that magnetic resonance imaging did not detect any im portant pathology in the large number of patients in this study strongly su ggests that magnetic resonance imaging is not indicated prior to arthrodesi s of the spine in patients with an adolescent idiopathic scoliosis curve pa ttern and a normal physical and neurologic examination.