Percutaneous Image-Guided Musculoskeletal Tumor Treatments

Thermal Evaluation of Multi-Antenna Systems Proposed to Treat Bone Tumors: Finite Element Analysis

Microwave ablation is commonly used in soft tissue tumors, but its application in bone tumors has been barely analyzed. Antennas to treat bone tissue (~3 cm2), has been lately designed. Bone tumors at pathological stage T1 can reach 8 cm wide. An antenna cannot cover it; therefore, our goal is to evaluate the thermal performance of multi-antenna arrays. Linear, triangular, and square configurations of double slot (DS) and monopole (MTM) antennas were evaluated. A parametric study (finite element method), with variations in distance between antennas (ad) and bone thickness (bt) was implemented. Array feasibility was evaluated by SWR, ablated tissue volume, etc. The linear configuration with DS and MTM antennas showed SWR ≤ 1.6 for ad = 1 mm−15 mm and bt = 20 mm−40 mm, and ad = 10 mm−15 mm and bt = 25 mm−40 mm, respectively; the triangular showed SWR ≤ 1.5 for ad = 5 mm−15 mm and bt = 20 mm−40 mm and ad = 10 mm−15 mm and bt = 25 mm−40 mm. The square configuration (DS) generated SWR ≤ 1.5 for ad = 5 mm−20 mm and bt = 20 mm−40 mm, and the MTM, SWR ≤ 1.5 with ad = 10 mm and bt = 25 mm−40 mm. Ablated tissue was 4.65 cm3−10.46 cm3 after 5 min. According to treatment time and array configuration, maximum temperature and ablated tissue is modified. Bone tumors >3 cm3 can be treated by these antenna-arrays.

Image-guided Cryotherapy for Musculoskeletal Tumors

BACKGROUND

This article represents a review of the use of image-guided cryotherapy in the treatment of musculoskeletal tumor lesions. Cryotherapy is able to induce a lethal effect on cancer cells through direct and indirect mechanisms. In this manuscript, we combined our experience with that of other authors who have published on this topic in order to provide indications on when to use cryotherapy in musculoskeletal oncology.

DISCUSSION

Image-Guided percutaneous cryotherapy is a therapeutic method now widely accepted in the treatment of patients with musculoskeletal tumors. It can be used both for palliative treatments of metastatic bone lesions and for the curative treatment of benign bone tumors, such as osteoid osteoma or osteoblastoma. In the treatment of bone metastases, cryotherapy plays a major role in alleviating or resolving disease-related pain, but it has also been demonstrated that it can have a role in local disease control. In recent years, the use of cryotherapy has also expanded for the treatment of both benign and malignant soft tissue tumors.

CONCLUSION

Percutaneous cryotherapy can be considered a safe and effective technique in the treatment of benign and malignant musculoskeletal tumors. Cryotherapy can be considered the first option in benign tumor lesions, such as osteoid osteoma, and a valid alternative to radiofrequency ablation. In the treatment of painful bone metastases, it must be considered secondarily to other standard treatments (radiotherapy, bisphosphonate therapy, and chemotherapy) when they are no longer effective in controlling the disease or when they cannot be repeated (for example, radiotherapy).

Interventional Techniques for the Ablation and Augmentation of Extraspinal Lytic Bone Metastases

In addition to being a major source of cancer-related pain, metastatic osseous lesions are frequently at risk for pathologic fracture and its accompanying morbidity. While bony metastases are commonly thought of as occurring within the vertebral column, over 80% are found outside the spine. Percutaneous interventional treatment options for nonspinal metastases offer a broad array of minimally invasive, image-guided procedures that are rapidly effective, reduce the need for opioids, and often work in complementary fashion with adjunct treatments in radiation oncology, orthopaedic surgery, and/or medical oncology. This article presents an approach to assess extraspinal metastases, reviews available interventional techniques in use today, and offers example cases as an introductory primer to the thought process used for selecting the appropriate interventional treatment.

Metastatic Osseous Pain Control: Bone Ablation and Cementoplasty

Nociceptive and/or neuropathic pain can be present in all phases of cancer (early and metastatic) and are not adequately treated in 56 to 82.3% of patients. In these patients, radiotherapy achieves overall pain responses (complete and partial responses combined) up to 60 and 61%. On the other hand, nowadays, ablation is included in clinical guidelines for bone metastases and the technique is governed by level I evidence. Depending on the location of the lesion in the peripheral skeleton, either the Mirels scoring or the Harrington (alternatively the Levy) grading system can be used for prophylactic fixation recommendation. As minimally invasive treatment options may be considered in patients with poor clinical status or limited life expectancy, the aim of this review is to detail the techniques proposed so far in the literature and to report the results in terms of safety and efficacy of ablation and cementoplasty (with or without fixation) for bone metastases. Percutaneous image-guided treatments appear as an interesting alternative for localized metastatic lesions of the peripheral skeleton.