Segmental Pedicle Screw Fixation for a Scoliosis Patient with Post-laminectomy and Post-irradiation Thoracic Kyphoscoliosis of Spinal Astrocytoma a* a a a b a a b
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August 2012 Spinal Deformity with Astrocytoma 365 55 58 Fig. 3 Preoperative computerized tomography. The laminae seemed to be regenerated. Fig. 2 Preoperative A-P, lateral radiography. Coronal Cobb angle was 55 degrees and kyphosis angle was 58 degrees. enough to maintain spinal instrumentation such as hooks or wires (Fig. 3). Spinal correction surgery was planned because the kyphoscoliosis of the patient was both severe and progressive, with the possibility of deteriorating to paralysis. To achieve the optimal correction in our patient, we performed a segmental pedicle screw fixation from T5 to L2. We inserted the pedicle screws using the StealthStationR navigation system (Medtronic Memphis, USA) (Fig. 4). Some lamina and spinous processes were too weak to hold the reference arc, in which cases we fixed the screw to the transverse process. Our navigation system requires surface registration, so the bilateral transverse process and remaining lamina were used for this. To minimize the registration time, the pedicle screws were inserted into 2 vertebrae at one registration: namely, into the registered vertebra and the one below. The registration time for each vertebra was approximately five minutes. The accuracy of the navigation was 0.3mm. The operative time was 5h and 45 min, and the estimated blood loss was 1,500ml. Postoperative radiograms demonstrated good correction of the curve, in both sagittal and coronal alignment. Postoperative Cobb angles were 15 degrees in the coronal plane and 30 degrees in the sagittal plane. The correction rate was 73ｵ in the coronal plane. There were no postoperative complications and no neurological compromise. Two weeks postoperatively, the patient could walk without support and was discharged from the hospital without a brace. He had good spinal balance at the 5-year follow-up examination (Fig. 5). Discussion Intramedullary spinal cord tumors are rare, accounting for 4-10ｵ of all tumors in the central nervous system [16]. Approximately 30ｵ of pediatric and adult intramedullary spinal cord tumors are astrocytomas, of which 80ｵ are histologically low grade [17, 18]. Recently, these tumors have become more easily diagnosed with magnetic resonance imaging, which characteristically shows the spinal cord as expanded or enhanced [19]. Most intramedullary spinal cord tumors can be surgically removed with acceptable morbidity and mortality rates [4-6], but if the tumor is not completely excised, it will eventually undergo malignant change, and radiation therapy or
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