Endoscope-assisted far-lateral transcondylar approach for craniocervical junction chordomas: a retrospective case series and cadaveric dissection.

Craniocervical junction (CCJ) chordomas are a neurosurgical challenge because of their deep localization, lateral extension, bone destruction, and tight relationship with the vertebral artery and lower cranial nerves. In this study, the authors present their surgical experience with the endoscope-assisted far-lateral transcondylar approach (EA-FLTA) for the treatment of CCJ chordomas, highlighting the advantages of this corridor and the integration of the endoscope to reach the anterior aspect and contralateral side of the CCJ and the possibility of performing occipitocervical fusion (OCF) during the same stage of surgery. Nine consecutive cases of CCJ chordomas treated with the EA-FLTA between 2013 and 2020 were retrospectively reviewed. Preoperative characteristics, surgical technique, postoperative results, and clinical outcome were analyzed. A cadaveric dissection was also performed to clarify the anatomical landmarks. The male/female ratio was 1.25, and the median age was 36 years (range 14-53 years). In 6 patients (66.7%), the lesion showed a bilateral extension, and 7 patients (77.8%) had an intradural extension. The vertebral artery was encased in 5 patients. Gross-total resection was achieved in 5 patients (55.6%), near-total resection in 3 (33.3%), and subtotal resection 1 (11.1%). In 5 cases, the OCF was performed in the same stage after tumor removal. Neither approach-related complications nor complications related to tumor resection occurred. During follow-up (median 18 months, range 5-48 months), 1 patient, who had already undergone treatment and radiotherapy at another institution and had an aggressive tumor (Ki-67 index of 20%), showed tumor recurrence at 12 months. The EA-FLTA provides a safe and effective corridor to resect extensive and complex CCJ chordomas, allowing the surgeon to reach the anterior, lateral, and posterior portions of the tumor, and to treat CCJ instability in a single stage.