Abstract
BACKGROUND: Chordomas of the upper cervical spine are rare. Recently, a relatively good long-term prognosis was reported for ion-beam radiotherapy. However, in a few cases, the tumor showed regrowth after radiotherapy. Resection is the treatment of choice in such cases, and spine surgery following ion-beam radiotherapy is associated with multiple complications. Here, the authors present a unique case of a C2 chordoma that showed regrowth after ion-beam radiotherapy. OBSERVATIONS: A 49-year-old man was diagnosed with a C2 chordoma and treated with ion-beam radiotherapy and posterior occipitocervical fusion. Five years later, the tumor showed regrowth, and complete macroscopic resection was successfully performed through mandibular splitting and the transoral approach under O-arm navigation assistance. However, wound healing of the posterior pharyngeal wall was unfavorable, and plastic surgeons created an osteocutaneous radial forearm free flap. Four years after surgery, no obvious local recurrence was observed. LESSONS: This case highlights a unique scenario in which chordoma regrowth occurs after ion-beam radiotherapy. An anterior approach and complete tumor removal may result in a good outcome, but the surgical incision close to the irradiated field may fail to fuse. Therefore, spine surgeons and plastic surgeons should closely coordinate for proper wound closure in patients after ion-beam radiotherapy. https://thejns.org/doi/10.3171/CASE25241.