2026 Poster Presentations
P245: NOVEL USE OF AUTOLOGOUS FAT STEM CELL INJECTIONS IN SKULL BASE OSTEORADIONECROSIS
Amreen B Karim1; Jason H Pomerantz, MD2; Ivan H El-Sayed, MD2; 1California Northstate University College of Medicine; 2University of California San Francisco
Introduction: Osteoradionecrosis (ORN) is a debilitating late complication of radiation therapy characterized by devitalized, non-healing bone within irradiated fields. While most reported cases involve patients with nasopharyngeal carcinoma (NPC), ORN can also occur after radiation for other skull base malignancies such as chordoma. Management remains challenging, with limited success from conservative therapy, modest results from hyperbaric oxygen, and high complication rates with surgical reconstruction. Regenerative approaches using mesenchymal stem cells, particularly adipose-derived stem cells (ADSCs), have emerged as a potential adjunct given their angiogenic and osteogenic properties. However, their role in skull base ORN has not been reported.
Methods: We describe two patients with skull base ORN who underwent ADSC therapy after exhausting conventional options. ADSCs were harvested by lipoaspiration, processed, and injected endoscopically into irradiated tissue beds adjacent to necrotic bone. Clinical outcomes were assessed with serial endoscopy, imaging, and symptom monitoring.
Results:
Case 1: A 60-year-old male with clival chordoma underwent expanded endonasal resection followed by stereotactic body radiation therapy. Five years later, he developed progressive clival ORN refractory to antibiotics, pentoxifylline, tocopherol, clodronate, and surgical debridement. Endoscopic injection of ADSCs into the prevertebral musculature and clival defect was performed, supplemented with a turbinate flap. At six months, viable ADSC sites and granulation tissue were observed with reduced exposed bone from 1 cm to 2 mm. Symptoms improved, including resolution of diplopia and reduced epistaxis, although partial necrosis persisted.
Case 2: A 54-year-old male with EBV-positive recurrent NPC underwent reirradiation with proton therapy and chemotherapy, followed by years of antibiotics, PENTOCLO, multiple debridements, inferior turbinate flap reconstruction, and sixty sessions of hyperbaric oxygen. Despite this, he developed progressive ORN adjacent to the carotid siphon with chronic epistaxis and exposed bone. ADSCs were injected into the nasopharynx and parapharyngeal space. Four months later, endoscopy revealed partial mucosalization, stable fat graft integration, and reduced epistaxis, with MRI confirming fat at injection sites. At seven months, necrosis remained stable without progression.
Panel 1: Patient 1 Pre-Treatment and Post-Treatment
Panel 2: Patient 2 MRI Pre-Treatment and Post-Treatment
Discussion: ORN remains a difficult-to-treat complication of skull base radiation, particularly in patients who have failed conservative therapy, medical management, and flap reconstruction. ADSCs offer advantages including high availability, minimal donor morbidity, and regenerative potential. Preclinical studies demonstrate their ability to enhance angiogenesis and osseous healing, while clinical series in breast and sarcoma patients suggest oncologic safety. Our cases show ADSC injections are technically feasible in the skull base, promote mucosal regeneration, and improve symptoms. However, persistent necrosis near critical structures underscores limitations of delivery.
Conclusion: This report describes the first ADSC therapy for skull base ORN in patients with both NPC and chordoma. ADSC injections were associated with improved mucosal healing, partial graft survival, and symptomatic benefit. While not curative, ADSC therapy may represent a promising adjunct for refractory skull base ORN. Larger studies with standardized protocols and longer follow-up are needed to define its role in the multidisciplinary management of radiation-induced necrosis.