Technical aspects of total spondylectomy of C2.

Background: Tumorous involvement of the second cervical vertebra is an infrequent, but severe disease. Primary tumors and solitary metastases can be addressed by a radical procedure, a complete removal of the whole compartment. The second cervical vertebra has a highly complex anatomy, and its operation requires considerable surgical skills. The aim of this retrospective study is to present technical aspects of complete resection of C2 for tumor indications, clinical and radiological evaluation of our group of patients and comparison of results of recent reports on surgery in this region in the literature.

Methods: Between 2006 and 2019 we performed 10 total resections of C2 for primary bone tumor or solitary metastasis at our department. Operation was indicated for chordoma in 4 cases and for other diagnoses (plasmacytoma, EWSA, metastases of papillary thyroid carcinoma, medullary thyroid carcinoma, lung carcinoma and sinonasal carcinoma) in one case each. The operative procedure was in all cases performed in two steps. It always started with the posterior approach. The anterior procedure was scheduled according to the patient's condition after an average interval of 16.9 days (range 7-21).

Results: A stable upper cervical spine was achieved in all patients. A solid bone fusion over the whole instrumentation was present in all living patients and they returned to their preoperative activity level. By the final follow-up 6 patients died: one patient died on the 5^th postop day because of diffuse uncontrollable bleeding from surgical wound, three patients died of generalization of the underlying disease and two patients due to complications associated with local recurrence of the disease. In addition to regular follow-ups, the surviving patients (N.=4) were also examined upon completion of the study, i.e., on average 91 months (range 17-179 months) postoperatively. With exclusion of an early deceased patient, the average follow-up period of deceased patients was 34.6 months (range 9-55) (N.=5). The average follow-up of the whole group of patients was 59,7 months (N.=9).

Conclusions: Total spondylectomy of C2 is an exceptional surgical procedure associated with risk of serious complications but offers chance for a complete recovery of the patient. Defining indications accurately, especially in solitary metastases, is very difficult even with current level of imaging and other testing. The quality of life of long-term surviving patients in our study was not significantly impacted.