Scoliosis may be the first symptom of the tethered spinal cord

Abstract

Background: Tethered cord syndrome (TCS) is a progressive clinical entity that arises from abnormal spinal cord tension. Scoliosis may be a unique symptom in TCS. The aim of this study is to investigate prognosis after releasing the filum terminale in scoliosis due to TCS with/without findings in magnetic resonance imaging (MRI) and to draw attention to the importance of somatosensorial evoked potentials (SSEP) on the differential diagnosis of idiopathic scoliosis versus scoliosis due to TCS with normal appearance of filum terminale and conus medullaris. Materials and Methods: Eleven female and seven male patients with progressive scoliosis were included in the study. They were evaluated radiologically, SSEP and urodynamical studies. Preoperative and postoperative anteroposterior full spine X-rays were obtained for measuring the Cobb's angle. MRI was performed in all cases for probable additional spinal abnormalities. All patients underwent filum terminale sectioning through a L5 hemilaminectomy. The resected filum terminale were subjected to histopathological examination. Results: The mean Cobb angle was 31.6 (range 18-45). Eight patients (44.45%) had a normal appearance of filum terminale and normal level conus medullaris in MRI, but conduction delay and/or block was seen on SSEP. In the histopathological examination of filum terminale dense collagen fibers, hyaline degeneration and loss of elastic fibers were observed. Postoperatively none of the patients showed worsening of the Cobb angle. Three patients showed improvement of scoliosis. Conclusion: In TCS presented with scoliosis, untethering must be performed prior to the corrective spinal surgery. Absence of MRI findings does not definitely exclude TCS. SSEP is an important additional guidance in the diagnosis of TCS. After untethering, a followup period of 6 months is essential to show it untethering helps in stopping the progress of the scoliotic curve. In spite of non progression (curve stopped lesser than 45) or even improvement of scoliosis, there may be no need for major orthopedic surgical intervention.