A 50-year-old man was sent to our department for preoperative embolization of a thoracic spine metastasis (Figure 1). The patient was undergoing treatment for renal cell carcinoma for 4 years. Three months before presenting to our department, a bone metastasis was diagnosed in the thoracic spine (T8 vertebra). One week before we received the patient for embolic therapy, he was symptomatic due to compression of the spinal cord. An open bone biopsy was performed 2 weeks earlier by the orthopedic surgeons, noteworthy for an intraoperative, life-threatening bleeding.

Bone metastasis is a very common finding in patients with renal cell carcinoma; those metastases are hypervascularized in the majority of cases. In the Austrian Bone and Soft Tissue Tumor Registry,1 20% of all patients with bone metastases showed renal cell carcinoma as a primary tumor; this is the second most common reason for bone metastases in the registry—only breast cancer metastases are more common (23%).

Clinical symptoms of bone metastases in this registry were pain (39%), fracture (27%), swelling (28%), and other (6%). In our patient, the symptoms consisted of neurologic symptoms due to spinal cord compression.

Preoperative embolization of metastases leads to a significant reduction of blood loss during the operation. In 2008, Kickhut et al2 published that the intraoperative blood loss during operation of hypervascularized metastases was reduced from 1,788 mL after partial occlusion to 1,119 mL with complete occlusion of the feeding vessels. At our hospital, almost all hypervascularized bone metastases are preoperatively embolized.

PROCEDURE DESCRIPTION

For the embolization procedure, the right common femoral artery was accessed, and a 6-F sheath was inserted. A 5-F sidewinder I catheter was used for diagnostic angiography of the intercostal arteries and guiding catheter purposes.

As a first step, the eighth intercostal artery was probed, diagnostic angiography showed a hypervascularization with a tumor blush (Figure 2), and there were large vessels feeding the diaphragm. For the embolization procedure, a steerable, Bern-shape Direxion™ Microcatheter with a 0.021-inch inner lumen was introduced. Another diagnostic angiogram via the microcatheter was obtained, which is possible using a 2-mL syringe or an automatic power injector. The right embolization position was reached using a Fathom®-16 Guidewire.

Distal to the hypervascularized tumor, three 2-mm Interlock™-18 Fibered Microcoils were placed via the Direxion™ Microcatheter in order to protect the diaphragm from particle embolization (Figure 3). Using this 0.021-inch microcatheter, delivery of the Interlock™ Fibered IDC Occlusion System is easy if the microcatheter is flushed with saline before particle or coil delivery.

Next, embolization of the tumor was performed with 100–300-μm particles until there was no more antegrade blood flow. Visibility of particles can be very low, even though they are mixed with contrast media. Especially in dangerous regions, such as the spine or the head/neck, I inject a very small amount of particles followed by a flush of contrast media in order to better visualize the particles and get an impression of the blood flow speed.

Stasis was reached quickly, and the inflow of the feeding artery was occluded using two 2-mm Interlock™-18 Fibered Microcoils. Control angiography showed a satisfying result with no remaining blood flow or tumor blush (Figure 4).

At the end of the procedure, four intercostal arteries had been embolized with particles (100–300 μm) and 15 total microcoils (diameters between 2 and 4 mm). The Direxion™ Microcatheter had to be repositioned many times in order to reach the optimal embolization position.

After the embolization procedure, there was no hypervascularized part of the tumor left (Figure 5). The patient had the operation the next day with radical resection of the thoracic spine metastases, including the metastatic soft tissue. The orthopedic surgeons reported that the tumor was “dry,” with no significant intraoperative blood loss.

Florian Wolf, MD, EBIR, EBCR, is Associate Professor of Radiology, Division of Cardiovascular and Interventional Radiology, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, in Vienna, Austria. He received no compensation related to this article. Dr. Wolf may be reached at florian.wolf@meduniwien. ac.at.

  1. Toma CD, Dominkus M, Nedelcu T, et al. Metastatic bone disease: a 36-year single centre trend-analysis of patients admitted to a tertiary orthopaedic surgical department. J Surg Oncol. 2007;96:404-410.
  2. Kickuth R, Waldherr C, Hoppe H, et al. Interventional management of hypervascular osseous metastasis: role of embolotherapy before orthopedic tumor resection and bone stabilization. AJR Am J Roentgenol. 2008;191:W240-W247. doi: 10.2214/AJR.07.4037.

 

Results from case studies are not necessarily predictive of results in other cases. Results in other cases may vary.