Application of intra-operative yellow fluorescence to intramedullary spinal cord ependymoma resection

Abstract

Objectives To study the application of intraoperative yellow fluorescence to intramedullary spinal cord ependymoma resection. Methods The clinical data of 83 in-patients with spinal cord tumors were retrospectively analyzed, who were admitted to Department of Neurosurgery, Beijing Tsinghua Changgung Hospital from December 2014 to December 2015. Among them, the diagnosis of intramedullary spinal cord ependymoma was histologically confirmed in 56 cases (39 men and 17 women), whose mean age was 43.5±4.2 years old (range: 31～65 years). All cases in this study received preoperative MRI scan to demonstrate the location, size and segment of tumors.Fluorescein sodium(3～4 mg/kg) was administered intravenously 30 minutes prior to anesthesia. Tumor resection was performed under alternation between conventional white light and yellow fluorescent light source. At 3 months post operation, MRI scans were conducted for observation of residual tumors, and spinal cord function was evaluated according to the McCormick scale. The mean follow-up period was 3 months. Results The rate of gross total resection (GTR)was 100.0% in this series of 56 cases. Among them, 47 cases were significantly stained under fluorescein sodium model (correlated with preoperative MRI enhancement) and received fluorescence-guided tumor resection.The other 9 cases with little staining (including 2 cases with little preoperative MRI enhancement and 4 cases demonstrating uneven MRI enhancement due to tumor apoplexy) underwent resection with conventional white light. Compared with 7-day and 1-month follow-ups, the 3-month postoperative improvement rates of sensory and motor functions were 83.0%(44/53)and 82.4%(42/51), respectively(P 0.05). Based on the McCormick grading system, 3.6%(2), 55.4%(31), 25.0%(14)and 16.1%(9)of the 56 patients were preoperatively categorized as gradeⅠ, Ⅱ, Ⅲ and Ⅳ, respectively. At 3 months post operation, 7.2%(32), 21.4%(12), 14.3%(8) and 7.1%(4) of the patients were categorized as gradeⅠ, Ⅱ, Ⅲ and Ⅳ, respectively, which demonstrated significant difference compared with preoperative conditions (P<0.01). The patients preoperatively categorized as grade Ⅰ and Ⅱ reported good surgical outcomes, while grade Ⅲ and Ⅳ patients did not. MRI results demonstratedno residual tumors or recurrence 3 months post operation. Conclusion Fluorescein sodium could be used for intramedullary ependymoma resection and contribute to complete excision of tumors. Key words: Spinal cord neoplasms; Ependymoma; Fluoresceins; Neurosurgical procedures