Dr Brown misspoke. No spinal tumor surgery that tricky would be dissected with an endoscope.
If Rose already had multiple rounds of preop chemo, she would have already had the portacath installed.
Cisplatin is not the correct drug treatment for osteosarcoma. The best results are usually achieved with MAP chemo which is a combination of methotrexate cisplatin and adriamycin together.
If preop chemo did not work, then it would most likely be changed to a different drug postoperatively.