Thermal effect of percutaneous radiofrequency ablation with a clustered electrode for vertebral tumors: In vitro and vivo experiments and clinical application

Temperature Monitoring in Hyperthermia Treatments of Bone Tumors: State-of-the-Art and Future Challenges

Bone metastases and osteoid osteoma (OO) have a high incidence in patients facing primary lesions in many organs. Radiotherapy has long been the standard choice for these patients, performed as stand-alone or in conjunction with surgery. However, the needs of these patients have never been fully met, especially in the ones with low life expectancy, where treatments devoted to pain reduction are pivotal. New techniques as hyperthermia treatments (HTs) are emerging to reduce the associated pain of bone metastases and OO. Temperature monitoring during HTs may significantly improve the clinical outcomes since the amount of thermal injury depends on the tissue temperature and the exposure time. This is particularly relevant in bone tumors due to the adjacent vulnerable structures (e.g., spinal cord and nerve roots). In this Review, we focus on the potential of temperature monitoring on HT of bone cancer. Preclinical and clinical studies have been proposed and are underway to investigate the use of different thermometric techniques in this scenario. We review these studies, the principle of work of the thermometric techniques used in HTs, their strengths, weaknesses, and pitfalls, as well as the strategies and the potential of improving the HTs outcomes.

Radiofrequency ablation may improve the beneficial results of vertebroplasty for vertebral hemangiomas: analysis of 46 patients

OBJECTIVES

To evaluate the effect of vertebroplasty (VP) alone or combined therapy of radiofrequency ablation (RFA) with vertebroplasty on pain relief with visual analog scale (VAS) and Oswestry Disability Index (ODI) scores in vertebral hemangiomas.

METHODS

Forty-six patients with hemangiomas were evaluated retrospectively: 20 males and 26 females were included. In group 1 (n = 25) only VP was performed, while RFA+VP were performed in the same treatment session in group 2 (n = 21). Radiological diagnosis was performed with X-ray, CT-scan and MRI images in all patients. The intensity of pain was assessed with the VAS together with the assesment of life quality with the ODI. The assesments were performed before, at first day, at first month and 6 months after treatment.

RESULTS

There was no significant difference between mean preprocedural VAS and ODI scores, but a significant decrease was seen in postprocedural VAS and ODI scores between group 1 and 2, when compared with the preprocedural values. Although lack of a statistically significant difference in long term results, mean VAS score was 3.7 for group 1, while it was 1.8 for group 2, and the mean ODI score was 38 for group 1, and 22.48 for group 2 at 6th month assesment.

DISCUSSION

Although minimally invasive percutaneous techniques are indicated as other modalities are ineffective or contraindicated, combining RFA with vertebral augmentation provide prevention of mechanical loading pain, and prevention of somatic pain in patients with spinal hemangiomas.

Contactless treatment for scoliosis by electromagnetically controlled shape-memory alloy rods: a preliminary study in rabbits

PURPOSE

To evaluate the safety and efficacy of a system aiming to correct scoliosis called "electromagnetically controlled shape-memory alloy rods" (EC-SMAR) used in a rabbit model.

METHODS

We heat-treated shape-memory alloy (SMA) rods to achieve a transition temperature between 34 and 47 °C and a C-shape austenite phase. We then developed a water-cooled generator capable of generating an alternating magnetic field (100 kHz) for induction heating. We next studied the efficacy of this system in vitro and determined some parameters prior to proceeding with animal experiments. We then employed a rabbit model, in which we fixed a straight rod along the spinous processes intraoperatively, and conducted induction heating postoperatively every 4 days for 1 month, while performing periodic X-ray assessments.

RESULTS

Significant kyphotic deformations with Cobb angles of about 45° (p < 0.01) were created in five rabbits, and no complications occurred throughout the experiment. The rabbits are still very much alive and do not show any signs of discomfort.

CONCLUSIONS

This is the first system that can modulate spinal deformation in a gradual, contactless, noninvasive manner through electromagnetic induction heating applied to SMA alloy rods. Although this study dealt with healthy spines, it provides promising evidence that this device also has the capacity to correct human kyphosis and even scoliosis in the future. These slides can be retrieved under Electronic Supplementary Material.