Intracranial Autograft Fat Placement to Separate the Optic Chiasm from Tumor to Improve Stereotactic Radiotherapy Dosimetry. World neurosurgery Turner, B. E., Schuler, E., Chang, S. D., Harsh, G. R., Soltys, S. G. 2020


Radiation therapy for intracranial lesions is constrained by dose to neurological organs at risk. We report two cases, a newly diagnosed chondrosarcoma and a previously irradiated meningioma, with tumors which abutted the optic chiasm following sub-total resection. Definitive radiotherapy would have required either undercoverage of the tumor or treatment of the chiasm with doses posing an unacceptable risk of blindness. Therefore, the patients underwent open surgery with placement of an abdominal fat autograft to provide space between the tumor and the optic structures at risk. Patients received definitive fractionated stereotactic radiotherapy. For each patient, we retrospectively compared the treated plan (with fat autograft) to a second plan generated utilizing the pre-autograft imaging, maintaining similar tumor coverage. For the chondrosarcoma, the fat autograft reduced the optic chiasm maximum dose (Dmax) by 21% (70.4 Gy to 55.3 Gy). For the re-irradiated peri-optic meningioma, the optic chiasm Dmax was reduced by 10% (50.8 Gy to 45.9 Gy), the left optic nerve by 17% (48.9 Gy to 40.4 Gy), and the right optic nerve by 30% (32.3 Gy to 22.6 Gy). We demonstrate the utility of abdominal fat autograft placement to maximize coverage of tumor while minimizing dose to intracranial organs at risk.

View details for DOI 10.1016/j.wneu.2020.10.110

View details for PubMedID 33130141