Abstract
INTRODUCTION: There are limited reports of C1 lateral mass reconstruction using a titanium mesh cage following the surgical removal of an aneurysmal bone cyst (ABC). We describe two uncommon and challenging cases of C1 ABC, highlighting the obstacles and complexities involved in selecting the appropriate approach for tumor resection, C1 stabilization, and reconstruction. CASE DISCUSSION: Case 1: A 12-year-old boy presented with 3 months of progressive upper cervical and occipital pain with no history of trauma. A heterogeneous lytic lesion with fluid-fluid levels in the right lateral mass of the atlas was detected. A gross total resection(GTR) of the C1 lateral mass ABC was performed through a posterior approach, followed by constructing the C1 lateral mass. Case 2 : An 11-year-old girl presented with cervical pain for the past 6 months. A cervical computed tomography (CT) scan without contrast revealed a lytic-expansile mass lesion with bony erosion in the right transverse process of the C1 vertebra. A similar surgical plan was tailored for this patient. A follow-up examination at 6 weeks demonstrated complete pain relief, and routine neurologic evaluations were uneventful. DISCUSSION: ABCs are uncommon, non-malignant, and highly vascular tumors, accounting for approximately 1% of all bone tumors and 15% of primary spinal tumors. The treatment of choice in this region is total resection, followed by C1 reconstruction. CONCLUSION: C1 lateral mass reconstruction using an expandable cage with vertebral artery (VA) preservation is recommended for extensive C1 lateral mass resection due to ABC.