gms | German Medical Science

Objective: Titan cages are widely used in the surgical treatment of spinal metastases. In most cases adjuvant radiotherapy is an essential part of treatment. Radiation target volumes are defined from postoperative imaging. However, titan cages lead to metal-related artifacts in CT imaging. Large PEEK polymer cages have recently been introduced to the market as parts of corporectomy systems. PEEK does not cause imaging artifacts and may be superior to titan cages in terms of more exact radiation planning. Our study evaluates the use of titan and PEEK cages implanted after corporectomy.

Methods: We retrospectively analyzed all cage implantations performed in our center on patients with metastatic spinal tumors between 2011 and 2015. Strong emphasis was put on the evaluation of radiation therapy concepts. Results were stratified by demographic data, tumor histology, tumor localization, prae- and postoperative Karnofsky Performance Status, oncologic concept and follow up radiographic findings.

Results: 24 patients were included into the study comparing 11 cases of PEEK and 13 cases of titan cage implantation. Tumor localization is 10% lumbar, 40% thoracic and 50% cervical spine. Dose homogenity is higher with PEEK cages, possibly hazardous dose maxima are lower in this group. Each group shows similar distributions of demographic and oncologic features. All patients underwent radiotherapy 4-6 weeks post to surgery. No case of implant failures was observed.

Conclusion: To our best knowledge this is the first study comparing the use of PEEK and titan after corporectomy in the metastatic spine. Due to decreased imaging artifacts radiotherapy planing is easier and a focused radiotherapy meaning a decrease in dose maxima and possibly associated side effects is more feasible. We do feel there is a benefit towards the use of PEEK cages in spinal metastases.