Microvascular Free Tissue Transfer for Skull Base Osteoradionecrosis: A Novel Approach in the Endoscopic ERA

Introduction: Osteoradionecrosis (ORN) of the skull base and craniovertebral junction is a challenging and life-threatening complication of radiation therapy (RT) for a variety of skull base and sinonasal malignancies. Though conservative management with hyperbaric oxygen and/or antibiotics may be successful in mild cases, severe ORN of the skull base often requires aggressive surgical intervention through multimodal approaches. As endoscopic surgery evolved, comparable advances in skull base reconstruction have also been made including the role of microvascular free tissue transfer (MFTT).

Objectives: Although MFTT has been described for skull base reconstruction, its unique role in the surgical management of skull base ORN remains poorly characterized. We aimed to describe an endoscopic-assisted, minimally invasive approach for the management of ORN of the posterior skull base and upper cervical vertebrae through the use of vascularized fascia lata for MFTT.

Methods: Between 2017 and 2021, we performed a retrospective review of all cases in which fascia lata MFTT was utilized for skull base ORN. Patient demographics, preoperative characteristics, prior interventions for ORN, and postoperative outcomes with long-term follow-up were reviewed.

Results: Five patients were identified. Baseline, prior pathology included embryonal rhabdomyosarcoma, clival chordoma, nasopharyngeal carcinoma, and squamous cell carcinoma of the nasopharynx, wherein all underwent RT with or without concurrent chemotherapy. Mean duration to onset of ORN was 17 months. All developed osteomyelitis in the setting of ORN, and antibiotic therapy was initiated for an average of 2.25 months. A trial of IV antibiotics, hyperbaric oxygen, and limited debridement was attempted with minimal success in all patients. ORN was centered in the upper clivus, craniovertebral junction, and upper cervical spine. Refractory pain and progressive osteomyelitis were unifying symptoms, with others including velopharyngeal insufficiency, cervical bone exposure and instability, and parapharyngeal mucosal necrosis. All patients underwent aggressive, endoscopic endonasal debridement of the affected bony and soft tissue region of ORN prior to MFTT. Vascularized fascia lata was inset through a combined endonasal and transoral corridor. A posterior, palatal split was required in 1 case to allow for inset due to severe trismus. In all cases, a small buccal and lateral pharyngeal incision was required for pedicle traverse and anastomosis to the facial vessels, which were isolated via a small incision at the antegonial notch. There was complete resolution in chronic cervical pain in the postop setting with no patients requiring continued IV antibiotics. On post-op imaging, there was no evidence of progressive ORN. Mean post-op follow-up was 15 months.

Conclusion: As we continue to push the boundaries in minimally invasive approaches for complex pathology, there is an expanding role and indication for early surgical management in refractory cases of ORN. Through our experience, we have developed a novel technique in the management of ORN of the posterior skull base and upper cervical spine with excellent postoperative outcomes and limited postoperative morbidity over extended follow-up.

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Artikel online veröffentlicht:
15. Februar 2022