Upper cervical spine reconstruction using customized 3D-printed vertebral body in 9 patients with primary tumors involving C2

Background: Reconstruction following resection of the primary tumors of the upper cervical spine is challenging, and conventional internal implants develop complications in this region. 3D printing, also known as additive manufacturing, can produce patient-specific porous implants in a particular shape for bone defect reconstruction. This study aimed to describe the clinical outcomes of upper cervical spine reconstruction using customized 3D-printed vertebral body in 9 patients with primary tumors involving C2. Methods: Patients with primary tumors involving C2 who were treated in our institution between July 2014 and November 2018 were enrolled. A two-stage intralesional spondylectomy was performed using the posterior-anterior approach. Anterior reconstruction was accomplished using a customized 3D-printed vertebral body, which was fabricated by successive layering of melted titanium alloy powder using electron beam melting. No bone graft was used. Results: Nine patients (2 males and 7 females) were included in the study with a mean age of 31.4 years (12 to 59 years). Seven patients demonstrated tumors located in C2 and 2 showed involvement of C2 and C3. During a mean follow-up of 28.6 months (range, 12-42 months), 1 patient died of systemic metastasis and 1 had local tumor recurrence, the other 7 patients were alive and functional in their daily living until the last follow-up without evidence of disease. The 3D-printed vertebral bodies were all stable with no sign of displacement or subsidence, evidence of implant osseointegration was observed on the imaging studies. For the posterior instrumentation systems, no screw loosening or rod breakage was found. Conclusions: Spinal reconstruction in the upper cervical region using customized 3D-printed vertebral body is reliable. The tailored shape matching with the contact surfaces and the porous structure conductive to osseointegration provide both short- and long-term stability to the implant.