Intraoperative application of yellow fluorescence in resection of intramedullary spinal canal ependymoma

Abstract

Background: Spinal ependymoma is the most common intramedullary tumor in adults. This study was performed to evaluate whether intraoperative yellow fluorescence use enhances our ability to identify the tumor margin and residual tumor tissue in intramedullary spinal cord ependymoma resection. We also evaluated patients' clinical conditions at a 3-month follow-up.

Methods: We retrospectively evaluated 56 patients with intramedullary ependymoma. Thirty minutes before anesthesia, the patients received intravenous sodium fluorescein injections. Tumor resection was performed under two illumination modes, traditional white light and yellow fluorescence, and the residual tumor tissue was detected. Magnetic resonance imaging was performed 3 months postoperatively to observe the tumor resection outcome and residual tumor tissue. The McCormick spinal cord function grade was evaluated preoperatively and 3 months postoperatively.

Results: The total resection rate was 100.0% in all patients. Nine patients had no significant fluorescence imaging. After 3 months, patients with a spinal function grade of I to IV showed significant spinal function improvement. Magnetic resonance imaging showed no residual tumor tissue or recurrence.

Conclusion: Sodium fluorescein aids in total excision of intramedullary spinal cord ependymoma and intraoperative residual tumor tissue identification. At the 3-month follow-up, the patients' functional outcome in the fluorescein group was good.

Keywords: Spinal cord tumor; ependymoma; functional outcome; neurosurgery; residual tumor; yellow fluorescence.

Figure 1.

Preoperative and postoperative magnetic resonance imaging (MRI) examinations and intraoperative microscopic findings of patients with intramedullary spinal cord ependymoma at the T3–7 thoracic vertebrae. (a) Preoperative MRI in which a sagittal T2 image shows an intramedullary spinal cord ependymoma exhibiting a relatively regular contour signal at the T3–7 thoracic vertebrae, with a rather clear boundary. (b) Preoperative MRI in which a sagittal enhanced scan shows no contrast enhancement of the tumor. (c) Intraoperative microscopy indicates that the tumor is located at the dorsal region of the spinal cord (shown by gray color) with a clear boundary. (d) Under yellow fluorescence, the tumor does not show enhanced contrast. (e) T2 sagittal MRI 3 months postoperatively showing no residual tumor, but a visible tumor cavity in the surgical region. (f) Sagittal enhanced MRI 3 months postoperatively indicating no residual tumor or recurrence.

Figure 2.

Intramedullary spinal cord ependymoma at the C1–T1 segment. (a)–(c) Preoperative magnetic resonance imaging (MRI) in which a T1 image shows a thickened spinal cord; a T2 image shows the intramedullary contour signal of masses in the C1–T1 segment, with visible syringes at both ends; and an enhanced scan shows significant contrast enhancement of the tumor. (d) and (e) Intraoperative microscopy shows the intactness and clear boundary of the tumor; under the fluorescence mode, enhanced contrast of the tumor was achieved, especially at the base of the tumor. (f) and (g) MRI 3 months postoperatively in which the T1 and T2 images indicate no residual tumor or recurrence.

Figure 3.

Preoperative and postoperative magnetic resonance imaging (MRI) examinations and intraoperative findings of patients with ependymoma. (a) Preoperative MRI in which a sagittal T2 image shows intramedullary masses with an irregular contour signal in the C2–T2 segment, with syringes visible at both ends. (b) Preoperative MRI in which a sagittal enhanced scan shows significant contrast enhancement of the tumor mass and enhanced syrinx walls at both ends. (c) The syrinx of a tumor at the head end is shown under white light; it is difficult to determine the presence of the tumor. (d) The contrast of the syrinx wall is clear under the fluorescence mode, and the mass was removed as a suspected tumor. (e) MRI examination 3 months postoperatively; a sagittal T2 image shows the tumor cavity after tumor resection. (f) MRI examination 3 months postoperatively; a sagittal enhanced MRI scan indicates no residual tumor or recurrence.