Preoperative Fiducial Marker Placement in the Thoracic Spine

Study Design. A retrospective review. Objective. The aim of this study was to demonstrate proof-of-concept of preoperative percutaneous intraosseous fiducial marker placement before thoracic spine surgery. Summary of Background Data. Wrong-level spine surgery is defined as a never event by Center for Medicare Services, yet the strength of data supporting the implementation of Universal Protocol to limit wrong level surgery is weak. The thoracic spine is especially prone to intraoperative mislocalization, particularly in cases of morbid obesity and anatomic variations. Methods. We retrospectively reviewed all cases of preoperative percutaneous image-guided intraosseous placement of a metallic marker in the thoracic spine. Indications for surgery included degenerative disc disease (16/19), osteochondroma resection, spinal metastasis, and ligation of dural arteriovenous malformation. All metallic markers were placed from a percutaneous transpedicular approach under imaging guidance [fluoroscopy and computed tomography (CT) or CT alone]. Patient body mass index (BMI) was recorded. Overweight and obese BMI was defined greater than 25 and 30 kg/m², respectively. Results. All 19 patients underwent fiducial marker placement and intraoperative localization successfully without complication. Twenty-two thoracic spine levels were localized. The T7, T9, T10, and T11 levels were the most often localized at rate of 18.1% for each level (4/22). The most cranial and caudal levels localized were T4 and T11. About 84.2% (16/19) of the cohort was overweight (57.9%; 11/19) or obese (26.3%; 5/19). The median BMI was 30.2 kg/m² (range, 23.9-54.3 kg/m²). Conclusion. Preoperative percutaneous thoracic fiducial marker placement under imaging guidance is a safe method for facilitating intraoperative localization of the target spinal level, especially in obese patients. Further studies are needed to quantify changes in operative time and radiation exposure.