Microsurgical Resection of Lung Carcinoma Spinal Cord Metastasis: 2-Dimensional Operative Video

Animal models of brain and spinal cord metastases of NSCLC established using a brain stereotactic instrument

Objective

Animal models of brain and spinal cord metastases of non-small cell lung cancer were established through the intracranial injection of PC-9 Luc cells with a brain stereotaxic device. This method provides a reliable modeling method for studying brain and spinal cord metastases of non-small cell lung cancer.

Methods

PC-9 Luc cells at logarithmic growth stage were injected into the skulls of 5-week-old BALB/c nude mice at different cell volumes (30 × 104, 80 × 104) and different locations (using anterior fontanel as a location point, 1 mm from the coronal suture, and 1.5 mm from the sagittal suture on the right upper and right lower side of the skull). After 1 week of cell inoculation, fluorescence signals of tumor cells in the brain and spinal were detected using the IVIS Xenogen Imaging system. After 4 weeks, brain and spinal tissues from the nude mice were harvested. Following paraffin-embedded sectioning, HE staining was performed on the tissues.

Results

The fluorescence signals revealed that both brain and spinal cord metastasis occurred in the mice where the cells were injected at the lower right side of the skull. There was only brain metastasis in the nude mice injected with 30 × 104 cells at the upper right side of the skull. Both brain and spinal cord metastasis occurred in the nude mice injected with 80 × 104 cells. The HE staining revealed that both brain and spinal cord metastasis occurred in the mice injected with different amounts of PC-9 Luc cells, consistent with the results detected using the IVIS Xenogen Imaging system, thereby demonstrating the reliability of detecting fluorescent signals in vivo to determine tumor growth.

Conclusion

It is a reliable method to establish the animal model of brain and spinal cord metastases of non-small cell lung cancer by injecting different quantities of cells from different positions with a brain stereotaxic device. The IVIS Xenogen Imaging system has high reliability in detecting the fluorescence signals of brain and spinal cord metastatic tumors.

Resection of Thoracic Intramedullary Breast Metastasis Through the Dorsal Root Entry Zone: 2-Dimensional Operative Video

Intramedullary spinal cord metastases (ISCMs) are rare, representing 8.5% of central nervous system metastases and 5% of intramedullary lesions.¹ With the advent of immunotherapy leading to longer-term survival for cancer patients, intramedullary metastases are on the rise.² A 43-year-old female presented with acute right leg weakness and sensory loss (Video 1). Magnetic resonance imaging revealed an avidly enhancing mass in the spinal cord at T6 with associated edema. Surgical resection was performed for tumor debulking to stabilize and ideally improve neurologic function, as well as for tissue acquisition for molecular profiling and targeted therapy. ISCMs are typically entered via midline myelotomy after a standard posterior exposure.³ However, on dural opening and visualization of the spinal cord, it was apparent that the tumor involved the right T6 nerve root. The decision was then made to enter the lesion via the T6 dorsal root entry zone (DREZ).⁴ Microsurgical resection of the tumor was performed with the aid of ultrasound and D-wave motor monitoring. Postoperative magnetic resonance imaging showed gross total resection and the patient was discharged to acute rehabilitation with increased right leg weakness and stable sensation. We demonstrate that for ISCM involving the exiting nerve root, DREZ myelotomy is a viable alternative to midline myelotomy. We strongly recommend use of D-wave monitoring in such cases as it clearly impacted our ability to maximize the resection. This is the first video where the DREZ approach is emphasized along with utilization of D-wave monitoring. The patient consented to the surgical procedure and the use of intraoperative video for education purposes.