Initial experience with the use of an expandable titanium cage as a vertebral body replacement in patients with tumors of the spinal column: a report of 95 patients

Abstract

Objective: Vertebral body resection to treat spine tumors necessitates reconstruction to maintain spinal stability. The durability of reconstruction may be a challenge in cancer patients as treatment with chemotherapy and/or radiation coupled with poor nutritional status may compromise bone quality. We present a series of patients who underwent implantation of an expandable titanium cage (ETC) for reconstruction after vertebral body resection for primary or metastatic spine tumors. We report the functional outcome, assess the durability of reconstruction, and describe complications associated with this procedure.

Methods: A retrospective review of patients undergoing placement of ETC after vertebrectomy for spinal tumor at our institution was performed.

Results: From September 2001 to August 2006, 95 patients underwent implantation of an ETC for reconstruction of the anterior spinal column following vertebrectomy for tumor (75 one-level, 19 two-level, 1 three-level). All patients underwent spinal stabilization as well. The median survival after surgery was 13.7 months; 23 patients had primary spinal tumors and 72 had metastatic tumors. Numerical pain scores were significantly improved postoperatively indicating a palliative benefit. No new neurological deficits were noted postoperatively, except when intentional neurological sacrifice was performed for oncologic reasons. Median height correction of 14% (range 0-118%) and median improvement in sagittal alignment of 6° (range 0-28°) were demonstrated on immediate postoperative imaging. Three patients experienced hardware related complications, one of which had posterior migration of the ETC. On postoperative imaging, 12 patients demonstrated subsidence of greater than 1 mm, but none required operative revision.

Conclusion: Use of an ETC for spinal reconstruction in patients with spinal tumors is safe, decreases pain associated with pathologic fracture, protects neurologic function, and is durable. We found a very low incidence of cage-related construct failures and no significant problems with subsidence.

Figures

Fig. 1

Methodology for determining percentage of height restoration. This patient underwent an L1 vertebrectomy for sarcoma after previous kyphoplasty. a Preoperative X-rays were used to measure the preoperative height of the diseased vertebral segment (L1) and the height of the normal vertebral body below (L2) at the midbody position. The preoperative normalized height was then calculated as a ratio L1/L2 (33.9/32.8 = 1.03). b Similarly, the postoperative sagittal CT reconstruction was used to calculate the normalized height after reconstruction L1/L2 (37.8/23.4 = 1.62). The percentage height correction is therefore 100 × (1.62 – 1.03)/1.03 = 57.3%

Fig. 2

Posterior approach for the placement of ETC in the thoracic spine. a Intraoperative photograph demonstrating placement of the ETC through a posterior approach after circumferential decompression. b Postoperative lateral X-ray demonstrating posterior stabilization and satisfactory positioning of ETC

Fig. 3

Site of disease in the vertebral column (N = 116 levels) in 95 patients

Fig. 4

A 62-year-old woman with metastatic breast cancer who underwent a T10 vertebrectomy and supplemental anterior plate. a Immediate postoperative X-rays demonstrating adequate cage position. b Sagittal CT reconstruction three weeks postoperatively demonstrating posterior migration of the ETC. Arrow denotes tumor involvement of the posterior elements, which contributed to ETC dislodgement