An expandable prosthesis with dual cage-and-plate function in a single device for vertebral body replacement: clinical experience on 14 cases with vertebral tumors

Abstract

An expandable vertebral body prosthesis with dual cage-and-plate function in a single device (JR prosthesis) was designed to test the hypothesis that this modular system can provide the biomechanical requirements for immediate and durable spine stabilization after corpectomy. Cadaver assays were performed with a stainless steal device to test fixation and adequacy to the human spine anatomy. Then, 14 patients with vertebral tumors (eight metastatic) underwent corpectomy and vertebral body replacement with a titanium-made JR prosthesis. All patients had neurological deficit, severe pain and spine instability prior to surgery. Mean pain score before surgery on a visual analog scale decreased from 7.6-3.0 points after operation (p = 0.002). All patients achieved at least one grade of improvement in the Frankel score (p = 0.003), excepting the three patients with Frankel grade A before surgery. Two patients with renal cell carcinoma died during the following 4 days after surgery. The remaining patients attained a painless and stable spine immediately, which was maintained for long periods (mean follow-up: 25.4 months). No significant infections or implant failures were registered. A nonfatal case of inferior vena cava surgical injury was observed (repaired during surgery without further complications). In conclusion, the JR prosthesis stabilizes the spine immediately after surgery and for the rest of the patients' life. To our knowledge, this is the first report on the clinical experience of any expandable vertebral body prosthesis with dual cage-and-plate function in a single device.