Endoscopic Endonasal Odontoidectomy with Anterior C1 Arch Preservation in Rheumatoid Arthritis: Long-Term Follow-Up and Further Technical Improvement by Anterior Endoscopic C1-C2 Screw Fixation and Fusion

OBJECTIVE: To examine the long-term outcomes (minimum of 4.5 years) of endoscopic endonasal odontoidectomy (EEO) with preservation of anterior C1 ring to treat irreducible ventral bulbo-medullary compressions in rheumatoid arthritis (RA) and to illustrate a novel technique of anterior pure endoscopic craniovertebral junction (CVJ) reconstruction and fusion. In fact, long-term clinical studies are still lacking to elucidate the effective role of EEO and whether it can obviate the need for posterior fixation. METHODS: From November 2008 to January 2012, clinical and radiologic data of 7 patients presenting with RA and associated irreducible bulbo-medullary compression treated with EEO were analyzed retrospectively. In all patients, decompression was achieved by EEO with anterior C1 arch preservation. In the last 2 patients, after EEO, we used the spared anterior C1 arch for reconstruction of anterior column of CVJ by positioning, under pure endoscopic guidance, autologous bone and 2 tricortical screws between the anterior arch of C1 and the residual odontoid. All patients were examined clinically with Ranawat classification and radiographically with computed tomography, magnetic resonance imaging, and dynamic radiography immediately after surgery and during follow-up. RESULTS: Adequate bulbo-medullary decompression with anterior C1 arch preservation was obtained in all cases. At follow-up (average, 66.2 months; range, 51-91 months) all patients experienced an improvement at least of one Ranawat classification level and presented no clinical or radiologic signs of instability. CONCLUSIONS: EEO with anterior C1 arch sparing provides satisfying long-term results for irreducible ventral CVJ lesions in RA. The preservation of anterior C1 arch and, when possible, the reconstruction of anterior CVJ can prevent the need for posterior fusion. KEYWORDS: Anterior endoscopic C1-C2 screw fixation; C1 arch preservation; Craniovertebral junction reconstruction; Endoscopic endonasal odontoidectomy; Rheumatoid arthritis and spine