New device lessens pain for patients with spinal tumors

The first person in Illinois to benefit from a new treatment device the OsteoCool^® Radiofrequency Ablation System from Medtronic was a middle-aged, camera-shy gentleman with widely metastatic renal cell cancer.

On May 3, 2016, Magdalena Anitescu, MD, PhD, associate professor and section chief of pain management in the Department of Anesthesia and Critical Care at the University of Chicago, used this newly approved tool to alleviate much of the pain caused by one of his tumors. The procedure helped regain his mobility, go for walks and enjoy a respite from what had been unrelenting discomfort.

The device, which received 510(k) clearance from the FDA in November 2015, uses radio-frequency energy to deliver heat, about 80 degrees Celsius (176 degrees, Farenheit), to destroy metastatic spinal tumors.

The goal is to reduce patient pain. Before the procedure, patient one ranked his pain as a nine out of ten, despite pain-relief medicines. Two days after the procedure, he rated his pain as a three out of ten. That increased slightly, to six, when he pushed his limits, going for longer walks and participating in activities at his home. But it was still a huge, welcome relief.

Painful metastatic bone tumors are distressingly common, affecting about 50 percent of patients with advanced cancers than began in the breast, prostate, liver or lung. Up to 30 percent of patients with spinal metastases do not respond to treatment with radiation, chemotherapy, surgery or conventional radiofrequency ablation, which uses heat, produced at the tip of a probe inserted into the tumor, to kill cancerous tissue. These probes can overheat, charring the tissue, which prevents the heat from reaching tumor cells outside that barrier.

The OsteoCool system uses two water-cooled probes that release heat but at a controlled lower temperature, to prevent charring. This enables the heat to extend farther into a tumor, slowly creating a spherical lesion up to eight times bigger than a typical char-inducing probe, according to Medtronic. The OsteoCool system spreads the heat over a region large enough to ablate most metastatic vertebral tumors, as well as any nearby nerve endings that transmit pain signals.

The May 3rd case took about 90 minutes, "but with experience we can get that down to an hour or less," Anitescu said.

The tumor that was causing the trouble was in the patient's thoracic spine, midway between his neck and lower back. It had taken over most of one vertebra, causing constant, excruciating pain and weakness.

This was not this patient's first vertebral tumor. X-rays of his spine resembled the scaffolding around a construction site, revealing multiple previous interventions that fused several vertebrae and reduced flexibility.

The operation, however, was fairly simple. The patient, heavily sedated, lay on his stomach. Anitescu and colleagues, guided by fluoroscopy, took careful measures of his back and marked exactly where they wanted to insert the probes.

They first inserted long needles to numb the skin, muscle and bone in the area. Then they inserted two thick, pointed, hollow screw-tipped needles, one on each side of the tumor-filled vertebra, twisting or tapping them gently into place with a small hammer.

Once those were in place, they passed the temperature-controlled probes through the needles and positioned them on either side of the tumor. Next, they raised the temperature for a few minutes, long enough to kill the tumor and any nearby pain sensors, but without harming healthy bone.

Finally, they pulled out the probes and filled the hollowed out space with about five cubic centimeters of bone cement, to reinforce the remaining bone.

The patient recovered well and went home that evening. Three weeks later, he returned to the clinic for a follow-up visit. His discomfort was clearly reduced and he was sitting up and chatting with his family and the doctors. "Overall, the procedure was very successful," said Anitescu. "He is more functional now, able to walk for longer periods of time." Her team has performed two subsequent more OsteoCool^®ablations since, one for myeloma and one for metastatic breast cancer. "All are doing great," Anitescu said. "The procedure is a success."