Interventional management of malignant bone tumours

In the last few decades, interventional radiology (IR) has significantly increased its role in the management of bone tumours including bone metastases (BM) that represent the most common type of tumour involving the bone. The current IR management of BM is based on the 'palliative-curative' paradigm and relies on the use of consolidative (i.e. osteplasty, osteosynthesis) and/or ablation (i.e. cryoablation, radiofrequency ablation, electrochemotherapy) techniques. The present narrative review will overview the current role of IR for the management of BM.

ACR Appropriateness Criteria® Management of Vertebral Compression Fractures: 2022 Update

Vertebral compression fractures (VCFs) can have a variety of etiologies, including trauma, osteoporosis, or neoplastic infiltration. Osteoporosis related fractures are the most common cause of VCFs and have a high prevalence among all postmenopausal women with increasing incidence in similarly aged men. Trauma is the most common etiology in those >50 years of age. However, many cancers, such as breast, prostate, thyroid, and lung, have a propensity to metastasize to bone, which can lead to malignant VCFs. Indeed, the spine is third most common site of metastases after lung and liver. In addition, primary tumors of bone and lymphoproliferative diseases such as lymphoma and multiple myeloma can be the cause of malignant VCFs. Although patient clinical history could help raising suspicion for a particular disorder, the characterization of VCFs is usually referred to diagnostic imaging. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Precision pain management in interventional radiology

Pain is a common manifestation of several benign and malignant conditions. Inadequate response to conservative therapies is often succeeded by incremental use of analgesics and opioids; however, such an approach is often ineffective, not well tolerated by patients, and carries the risk of addiction leading to the opioid crisis. Implementing minimally invasive percutaneous procedures, performed by interventional radiologists has proven to be successful in providing safe, effective, and patient-specific therapies across a wide range of painful conditions. In the present narrative review, we will review the repertoire of minimally invasive imaging guided interventions, which have been successfully used to treat common painful benign and malignant conditions. We briefly describe each technique, common indications, and expected results.

Safety and Feasibility of Steerable Radiofrequency Ablation in Combination with Cementoplasty for the Treatment of Large Extraspinal Bone Metastases

Background: Radiofrequency ablation (RFA) and cementoplasty, individually and in concert, has been adopted as palliative interventional strategies to reduce pain caused by bone metastases and prevent skeletal related events. We aim to evaluate the feasibility and safety of a steerable RFA device with an articulating bipolar extensible electrode for the treatment of extraspinal bone metastases. Methods: All data were retrospectively reviewed. All the ablation procedures were performed using a steerable RFA device (STAR, Merit Medical Systems, Inc., South Jordan, UT, USA). The pain was assessed with a VAS score before treatment and at 1-week and 3-, 6-, and 12-month follow-up. The Functional Mobility Scale (FMS) was recorded preoperatively and 1 month after the treatment through a four-point scale (4, bedridden; 3, use of wheelchair; 2, limited painful ambulation; 1, normal ambulation). Technical success was defined as successful intraoperative ablation and cementoplasty without major complications. Results: A statistically significant reduction of the median VAS score before treatment and 1 week after RFA and cementoplasty was observed (p < 0.001). A total of 6/7 patients who used a wheelchair reported normal ambulation 1 month after treatment. All patients with limited painful ambulation reported normal ambulation after the RFA and cementoplasty (p = 0.003). Technical success was achieved in all the combined procedures. Two cement leakages were reported. No local recurrences were observed after 1 year. Conclusions: The combined treatment of RFA with a steerable device and cementoplasty is a safe, feasible, and promising clinical option for the management of painful bone metastases, challenging for morphology and location, resulting in an improvement of the quality of life of patients.

Radiofrequency Ablation of Spine Metastases: A Clinical and Technical Approach

Percutaneous radiofrequency ablation (RFA) is an integral component of the multidisciplinary treatment algorithm for both local tumor control and palliation of painful spine metastases. This minimally invasive therapy complements additional treatment strategies, such as pain medications, systemic chemotherapy, surgical resection, and radiotherapy. The location and size of the metastatic lesion dictate preprocedure planning and the technical approach. For example, ablation of lesions along the spinal canal, within the posterior vertebral elements, or with paraspinal soft tissue extension are associated with a higher risk of injury to adjacent spinal nerves. Additional interventions may be indicated in conjunction with RFA. For example, ablation of vertebral body lesions can precipitate new, or exacerbate existing, pathologic vertebral compression fractures that can be prevented with vertebral augmentation. This article reviews the indications, clinical work-up, and technical approach for RFA of spine metastases.

Interventional Procedures for Vertebral Diseases: Spinal Tumor Ablation, Vertebral Augmentation, and Basivertebral Nerve Ablation-A Scoping Review

Low back pain is consistently documented as the most expensive and leading cause of disability. The majority of cases have non-specific etiologies. However, a subset of vertebral diseases has well-documented pain generators, including vertebral body tumors, vertebral body fractures, and vertebral endplate injury. Over the past two decades, specific interventional procedures targeting these anatomical pain generators have been widely studied, including spinal tumor ablation, vertebral augmentation, and basivertebral nerve ablation. This scoping review summarizes safety and clinical efficacy and discusses the impact on healthcare utilization of these interventions. Vertebral-related diseases remain a top concern with regard to prevalence and amount of health care spending worldwide. Our study shows that for a subset of disorders related to the vertebrae, spinal tumor ablation, vertebral augmentation, and basivertebral nerve ablation are safe and clinically effective interventions to decrease pain, improve function and quality of life, and potentially reduce mortality, improve survival, and overall offer cost-saving opportunities.

The Role of a Navigational Radiofrequency Ablation Device and Concurrent Vertebral Augmentation for Treatment of Difficult-to-Reach Spinal Metastases

Aims: The purpose of this study was to assess the effectiveness of a navigational radiofrequency ablation device with concurrent vertebral augmentation in the treatment of posterior vertebral body metastatic lesions, which are technically difficult to access. Primary outcomes of the study were evaluation of pain palliation and radiologic assessment of local tumor control. Materials and Methods: Thirty-five patients with 41 vertebral spinal metastases involving the posterior vertebral body underwent computed tomography-guided percutaneous targeted radiofrequency ablation, with a navigational radiofrequency ablation device, associated with vertebral augmentation. Twenty-one patients (60%) had 1 or 2 metastatic lesions (Group A) and fourteen (40%) patients had multiple (>2) vertebral lesions (Group B). Changes in pain severity were evaluated by visual analog scale (VAS). Metastatic lesions were evaluated in terms of radiological local control. Results: The procedure was technically successful in all the treated vertebrae. Among the symptomatic patients, the mean VAS score dropped from 5.7 (95% CI 4.9–6.5) before tRFA and to 0.9 (95% CI 0.4–1.3) after tRFA (p < 0.001). The mean decrease in VAS score between baseline and one week follow up was 4.8 (95% CI 4.2–5.4). VAS decrease over time between one week and one year following radiofrequency ablation was similar, suggesting that pain relief was immediate and durable. Neither patients with 1–2 vertebral metastases, nor those with multiple lesions, showed radiological signs of local progression or recurrence of the tumor in the index vertebrae during a median follow up of 19 months (4–46 months) and 10 months (4–37 months), respectively. Conclusion: Treatment of spinal metastases with a navigational radiofrequency ablation device and vertebral augmentation can be used to obtain local tumor control with immediate and durable pain relief, providing effective treatment in the multimodality management of difficult-to-reach spinal metastases.

Radiofrequency ablation and balloon kyphoplasty for palliation of painful spinal metastases

PURPOSE

This study was designed with an aim to assess the safety and early postoperative outcomes of the combined Radiofrequency ablation (RFA) and Balloon Kyphoplasty (BKP) used for the treatment of painful neoplastic spinal lesions palliatively.

PATIENTS AND METHODS

Between December 2015 and December 2018, 60 patients (35 men and 25 women) with spinal metastases were operated using RFA and BKP at our institution. Transpedicular biopsy was performed in all cases. Patients' demographics, lesion characteristics, concurrent palliative therapies and complications were recorded. All patients were clinically (Pain score VAS 0-10) and radiologically evaluated pre- and postoperatively. Retrospective analysis of data for this cohort was performed.

RESULTS

Seventy-five painful spinal metastases (46 in the lumbar spine and 29 in the thoracic region) in 60 patients were operated [transpedicular RFA alone in 5 lesions, and in combination with BKP in 70 lesions (93%)]. The mean pre-procedure and post-procedure VAS for back pain was 7.2/10 and 2.7/10, respectively (p value = 0.0001). No neurological complications related to RFA were found and no cement extravasation into the spinal canal was observed. In two patients, asymptomatic leaks into the needle track, in two patients into draining veins and in one patient into the disk space were detected.

CONCLUSION

Combined RFA and BKP appears to be a safe, practical, effective and reproducible palliative treatment for painful spinal osteolytic metastasis. In carefully indicated cases, it relieves pain and maintains stability in a minimal invasive way without adding significant surgical trauma or complications.

Percutaneous bipolar radiofrequency ablation for spine metastatic lesions

PURPOSE

The purpose of this review is to become familiar with the most common indications for imaging guided percutaneous bipolar radiofrequency ablation, to learn about different technical considerations during performance providing the current evidence. Controversies concerning products will be addressed.

METHODS

We performed a literature review excluding non-English studies and case reports. All references of the obtained articles were also evaluated for any additional information.

RESULTS

RFA achieves cytotoxicity by raising target area temperatures above 60 °C, and may be used to achieve total necrosis of lesions smaller than 3 cm in diameter, to debulk and reduce the pain associated with larger lesions, to prevent pathological fractures due to progressive osteolysis or for cavity creation aiming for targeted cement delivery in case of posterior vertebral wall breaching. Protective ancillary techniques should be used in order to increase safety and augment efficacy of RFA in the spine.

CONCLUSION

Percutaneous radiofrequency ablation of vertebral lesions is a reproducible, successful and safe procedure. Ablation should be combined with vertebral augmentation in all cases. In order to optimize maximum efficacy a patient- and a lesion-tailored approach should both be offered focusing upon clinical and performance status along with life expectancy of the patient as well as upon lesion characteristics.

Complications of Percutaneous Radiofrequency Ablation of Spinal Osseous Metastases: An 8-Year Single-Center Experience

OBJECTIVE. The purpose of this article was to evaluate the complication rate of percutaneous radiofrequency ablation of spinal osseous metastases. MATERIALS AND METHODS. This retrospective HIPAA-compliant study reviewed complications of radiofrequency ablation combined with vertebral augmentation performed on 266 tumors in 166 consecutive patients for management of vertebral metastases between January 2012 and August 2019. Common Terminology Criteria for Adverse Events (CTCAE) was used to categorize complications as major (grade 3-4) or minor (grade 1-2). Local tumor control rate as well as pain palliation effects evaluated by the Brief Pain Inventory scores determined 1 week, 1 month, 3 months, and 6 months after treatment were documented. Wilcoxon signed rank and Mann-Whitney U tests were used for statistical analysis. RESULTS. Among 266 treated tumors, the total complication rate was 3.0% (8/266), the major complication rate was 0.4% (1/266), and the minor complication rate was 2.6% (7/266). The single major (CTCAE grade 3) periprocedural complication was characterized by lower extremity weakness, difficulty in urination, and lack of erection as a result of spinal cord venous infarct. The seven minor complications included four cases of periprocedural transient radicular pain (CTCAE grade 2) requiring transforaminal steroid injections, one case of delayed secondary vertebral body fracture (CTCAE grade 2) requiring analgesics, and two cases of asymptomatic spinal cord edema on routine follow-up imaging (CTCAE grade 1). The local tumor control rate was 78.9%. There were statistically significant pain palliation effects at all postprocedural time intervals (p < .001 for all). CONCLUSION. Radiofrequency ablation of spinal osseous metastases is safe with a 3.0% rate of complications.

Radiation therapy alone versus radiation therapy plus radiofrequency ablation/vertebral augmentation for spine metastasis: study protocol for a randomized controlled trial

Background

Spine metastasis is a common occurrence in cancer patients and results in pain, neurologic deficits, decline in performance status, disability, inferior quality of life (QOL), and reduction in ability to receive cancer-directed therapies. Conventional external beam radiation therapy (EBRT) is associated with modest rates of pain relief, high rates of disease recurrence, low response rates for those with radioresistant histologies, and limited improvement in neurologic deficits. The addition of radiofrequency ablation/percutaneous vertebral augmentation (RFA/PVA) to index sites together with EBRT may improve pain response rates and corresponding quality of life.

Methods/design

This is a single-center, prospective, randomized, controlled trial in patients with spine metastasis from T5-L5, stratified according to tumor type (radioresistant vs. radiosensitive) in which patients in each stratum will be randomized in a 2:1 ratio to either RFA/PVA and EBRT or EBRT alone. All patients will be treated with EBRT to a dose of 20–30 Gy in 5–10 fractions. The target parameters will be measured and recorded at the baseline clinic visit, and daily at home with collection of weekly measurements at 1, 2, and 3 weeks after treatment, and at 3, 6, 12, and 24 months following treatment with imaging and QOL assessments.

Discussion

The primary objective of this randomized trial is to determine whether RFA/PVA in addition to EBRT improves pain control compared to palliative EBRT alone for patients with spine metastasis, defined as complete or partial pain relief (measured using the Numerical Rating Pain Scale [NRPS]) at 3 months. Secondary objectives include determining whether combined modality treatment improves the rapidity of pain response, duration of pain response, patient reported pain impact, health utility, and overall QOL.

Trial registration

ClinicalTrials.gov NCT04375891. Registered on 5 May 2020.

Comparison of post-operative pain scores and opioid use between kyphoplasty and radiofrequency ablation (RFA) systems combined with cement augmentation

OBJECTIVE

This retrospective chart review study aims to compare demographic information, post-operative pain scores, and opioid use following treatment with kyphoplasty alone, OsteoCool™ (Medtronic) system, and SpineSTAR ® (Merit Medicine).

MATERIALS AND METHODS

Following institutional review board approval, retrospective chart review of 64 patients was examined between January 2011 and December 2017. Inclusion criteria for this study comprised patients greater than 18 years old having metastatic vertebral compression fracture involving the thoracolumbar spine. Exclusion criteria consisted of non-pathologic osteoporotic compression fractures, metastasis in cervical spine, or previous radiofrequency ablation (RFA) treatment. Age at intervention, gender, previous treatment, and nursing recorded VAS score from 0 to 10, with zero representing no pain and 10 representing worst pain were compared. Pain scores documented immediately pre- and post-operatively, as well as 7-14 days post-operatively were targeted for analysis. Post-procedure opioid intake during the first month following surgery was also assessed.

RESULTS

A total of 63 patients were included in this retrospective analysis. The demographic characteristics between the treatment arms were similar. Difference of square means analysis showed no statistical difference in pain scores at each time interval between the two RFA systems, or was there a statistical difference in pain scores when each RFA system was compared independently to kyphoplasty alone. Chi-squared analysis showed no statistical difference in opioid use between the treatment arms 1 month post-operatively.

DISCUSSION

To our knowledge, this is the first study that evaluates post-operative pain scores between the two novel RFA systems and kyphoplasty alone. Each system results in improved pain scores post-operatively; however, no additional benefit was seen from the addition of RFA.

Musculoskeletal interventional oncology: current and future practices

Management of musculoskeletal (MSK) tumours has traditionally been delivered by surgeons and medical oncologists. However, in recent years, image-guided interventional oncology (IO) has significantly impacted the clinical management of MSK tumours. With the rapid evolution of relevant technologies and the expanding range of clinical indications, it is likely that the impact of IO will significantly grow and further evolve in the near future.

In this narrative review, we describe well-established and new interventional technologies that are currently integrating into the IO armamentarium available to radiologists to treat MSK tumours and illustrate new emerging IO indications for treatment.

Vertebral Metastases: Minimally Invasive Percutaneous Thermal Ablation

This article provides a step-by-step guide for minimally invasive percutaneous image-guided thermal ablation for treatment of vertebral metastases. Such interventions have proved safe and effective in management of selected patients with spinal metastases primarily to achieve pain palliation and local tumor control. Particular attention to patient selection guidelines, details of procedure techniques, thermal protection, adequacy of treatment, recognition and management of potential complications, and post-ablation imaging are essential for improved patient outcomes.

Spinal Tumor Ablation: Indications, Techniques, and Clinical Management

Percutaneous thermal ablation has proven to be safe and effective in the management of patients with spinal tumors. Such treatment is currently proposed following the decision of a multidisciplinary tumor board to patients with small painful benign tumors such as osteoid osteoma or osteoblastoma, as well as carefully selected patients presenting with spinal metastases. In both scenarios, in order to provide a clinically effective procedure, ablation is often tailored to the specific patients' clinical needs and features of the target tumor. In this review, we present the most common clinical contexts in which spine ablation may be proposed. We scrutinize technical aspects and challenges that may be encountered during the procedure, as well as offering insight on follow-up and expected outcomes.

Percutaneous Interventional Techniques for Treatment of Spinal Metastases

This article details an approach for evaluation as well as minimally invasive percutaneous treatment of spinal metastases focusing on thermal ablation and most recent advances. Safe and effective management of certain subgroups of patients with spinal metastases can be achieved by minimally invasive percutaneous thermal ablation with or without vertebral augmentation. Adjunctive palliative treatment options such as epidural or neuroforaminal corticosteroid and long-acting anesthetic injections may also be performed in patients who have nerve and radicular pain including those who are not candidates for thermal ablation. Thermal protection strategies should be implemented to minimize the risk of neural thermal injury.

Utility of Motor and Somatosensory Evoked Potentials for Neural Thermoprotection in Ablations of Musculoskeletal Tumors

PURPOSE

To characterize the utility of monitoring transcranial electrical motor evoked potentials (TCeMEPs) and somatosensory evoked potentials (SSEPs) for neural thermoprotection during musculoskeletal tumor ablations.

MATERIALS AND METHODS

Retrospective review of 29 patients (16 male; median age, 46 y; range, 7-77 y) who underwent musculoskeletal tumor radiofrequency ablation (n = 8) or cryoablation (n = 22) with intraprocedural TCeMEP and SSEP monitoring was performed. The most common tumor histologies were osteoid osteoma (n = 6), venous malformation (n = 5), sarcoma (n = 5), renal cell carcinoma (n = 4), and non-small-cell lung cancer (n = 3). The most common tumor sites were spine (n = 22) and lower extremities (n = 4). Abnormal TCeMEP change was defined by 100-V increase above baseline threshold activation for a given myotome; abnormal SSEP change was defined by 60% reduction in baseline amplitude and/or 10% increase in latency.

RESULTS

Abnormal changes in TCeMEP (n = 9; 30%) and/or SSEP (n = 5; 17%) occurred in 12 procedures (40%) and did not recover in 5 patients. Patients with unchanged TCeMEP/SSEP activities throughout the procedure (n = 18) did not have motor or sensory symptoms after the procedure; 3 (60%) with unrecovered activity changes and 2 (29%) with transient activity changes had new motor (n = 1) or sensory (n = 4) symptoms. Relative risk for neurologic sequelae for patients with unrecovered TCeMEP/SSEP changes vs those with transient or no changes was 7.50 (95% confidence interval, 1.66-33.9; P = .009).

CONCLUSIONS

Abnormal activity changes of TCeMEP or SSEP during percutaneous ablative procedures correlate with postprocedural neurologic sequelae.

Lower Extremity Paralysis After Radiofrequency Ablation of Vertebral Metastases

BACKGROUND

Radiofrequency ablation (RFA) focally destroys abnormal or dysfunctional tissue using thermal energy generated from alternating current. The utilization of RFA has gained popularity as a minimally invasive procedure for the treatment of skeletal metastases with a particular focus on palliative pain treatments to the spine, pelvis, long bones, sternum, and glenoid. More recently, single-session procedures that combine RFA with vertebral augmentation techniques have allowed treatment to areas of pain associated with pathologic fractures secondary to metastatic disease. Although many studies have been done to investigate the safety and efficacy of RFA, there have been no reported cases to date in which the use of RFA for the treatment of spinal metastases has led to any major permanent neurological injury.

CASE DESCRIPTION

This report describes a case of a 61-year-old woman who underwent RFA and kyphoplasty for spinal metastases and noted the immediate onset of lower extremity paralysis after the procedure. To the best of our knowledge, this is the first documented case of permanent lower extremity paralysis in the medical literature after radiofrequency thermal ablation of spine metastases.

CONCLUSIONS

Postoperative magnetic resonance imaging and physical examination suggest RFA-induced thermal injury as the most likely mechanism of paralysis. In this report, a review of previous in vivo models used in studying the efficacy and safety of spine RFA is conducted. Additionally, the literature has been reviewed for any neurological events reported with the use of RFA in the treatment of patients with vertebral pathology.

Image guidance in spine tumor surgery

Beginning with basic stereotactic operative methods in neurosurgery, intraoperative navigation and image guidance systems have since become the norm in that field. Following the introduction of image guidance into spinal surgery, there has been a dramatic increase in its utilization across disciplines and pathologies. Spine tumor surgery encompasses a wide range of complex surgical techniques and treatment strategies. Similarly to deformity correction and trauma surgery, spine navigation holds potential to improve outcomes and optimize surgical technique for spinal tumors. Recent data demonstrate the applicability of neuro-navigation in the field of spinal oncology, particularly for spinal stabilization, maximizing extent of resection and integration of minimally invasive therapies. The rapid introduction of new, less invasive, and ablative surgical techniques in spine oncology coupled with the rising incidence of spinal metastatic disease make it imperative for spine surgeons to be familiar with the indications for and limitations of imaging guidance. Herein, we provide a practical, current concepts narrative review on the use of spinal navigation in three areas of spinal oncology: (a) extent of tumor resection, (b) spinal column stabilization, and (c) focal ablation techniques.

ACR Appropriateness Criteria® Management of Vertebral Compression Fractures

Vertebral compression fractures (VCFs) have various causes, including osteoporosis, neoplasms, and acute trauma. As painful VCFs may contribute to general physical deconditioning, management of painful VCFs has the potential for improving quality of life and preventing superimposed medical complications. Various imaging modalities can be used to evaluate a VCF to help determine the etiology and guide intervention. The first-line treatment of painful VCFs has been nonoperative or conservative management as most VCFs show gradual improvement in pain over 2 to 12 weeks, with variable return of function. There is evidence that vertebral augmentation (VA) is associated with better pain relief and improved functional outcomes compared to conservative therapy for osteoporotic VCFs. A multidisciplinary approach is necessary for the management of painful pathologic VCFs, with management strategies including medications to affect bone turnover, radiation therapy, and interventions such as VA and percutaneous thermal ablation to alleviate symptoms. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

A systematic review of interventions and outcomes in lung cancer metastases to the spine

Seventy percent of cancer patients will have metastatic bone disease, most commonly in the vertebra. Prognosis of metastatic lung cancer is poor and treatment is mostly palliative. To-date, there is no systematic review on the ideal treatment for lung cancer with spinal metastases in regards to mortality. Literature searches were performed based on PRISMA guidelines for systematic review. Thirty-nine studies comprising 1925 patients treated for spinal metastases of lung cancer met inclusion criteria. All analyses were performed using SAS and SPSS. Data were analyzed for meaningful comparisons of baseline patient characteristics, primary cancer type, metastatic lesion characteristics, treatment modality, and clinical and radiologic outcomes. Significantly greater mean survival length was seen in the non-surgical group (8.5 months, SD 6.6, SEM 0.17) compared to the surgical group (7.5 months, SD 4.5, SEM 0.25; p = 0.013). There was no statistically significant survival difference between different types of primary lung cancer: NSCLC (8.3 months, SD 13.8, SEM 0.91) and SCLC (7.0 months, SD 4.6, SEM 0.46; p = 0.36). Number of vertebral levels involved per lesion also did not exhibit significant difference: single lesion (11.3 months, SD 6.8, SEM 2.2) and multiple lesions (13.8 months, SD 15.7, SEM 3.6; p = 0.64). For patients with symptomatic spinal metastases from lung cancer, non-operative approaches experience significantly better survival outcomes (p = 0.013). Future clinical studies are needed to determine the best treatment algorithm to help maximize outcomes and minimize mortality in metastatic lung cancer.

Thermal Ablation of Bone Metastases

Image-guided, minimally invasive, percutaneous thermal ablation of bone metastases has unique advantages compared with surgery or radiation therapy. Thermal ablation of osseous metastases may result in significant pain palliation, prevention of skeletal-related events, and durable local tumor control. This article will describe current thermal ablation techniques utilized to treat bone metastases, summarize contemporary evidence supporting such thermal ablation treatments, and outline an approach to percutaneous ablative treatment.

Percutaneous Radiofrequency Ablation of Spinal Osteoid Osteomas Using a Targeted Navigational Bipolar Electrode System

Safe and effective percutaneous CT-guided radiofrequency ablation of spinal osteoid osteomas can be performed using a targeted navigational bipolar electrode system. Articulating bipolar electrodes with built-in thermocouples along an electrode shaft and variable generator wattage settings allow optimal nidus access, particularly in challenging locations; provide precise real-time monitoring of ablation zone volume and geometry; and minimize the risk of undesired thermal injury.

Simultaneous Bipedicular Radiofrequency Ablation Combined with Vertebral Augmentation for Local Tumor Control of Spinal Metastases

BACKGROUND AND PURPOSE

Percutaneous radiofrequency ablation combined with vertebral augmentation has emerged as a minimally invasive treatment for patients with vertebral metastases who do not respond to or have contraindications to radiation therapy. The prevalence of posterior vertebral body metastases presents access and treatment challenges in the unique anatomy of the spine. The purpose of this study was to evaluate the safety and efficacy of simultaneous bipedicular radiofrequency ablation using articulating bipolar electrodes combined with vertebral augmentation for local tumor control of spinal metastases.

MATERIALS AND METHODS

Imaging-guided simultaneous bipedicular radiofrequency ablation combined with vertebral augmentation was performed in 27 patients (33 tumors) with vertebral metastases selected following multidisciplinary consultations, to achieve local tumor control in this retrospective study. Tumor characteristics, procedural details, and complications were documented. Pre- and postprocedural cross-sectional imaging was evaluated to assess local tumor control rates.

RESULTS

Thirty-three tumors were successfully ablated in 27 patients. Posterior vertebral body or pedicle involvement or both were present in 94% (31/33) of cases. Sixty-seven percent (22/33) of the tumors involved ≥75% of the vertebral body volume. Posttreatment imaging was available for 79% (26/33) of the treated tumors. Local tumor control was achieved in 96% (25/26) of tumors median imaging follow up of 16 weeks. No complications were reported, and no patients had clinical evidence of metastatic spinal cord compression at the treated levels.

CONCLUSIONS

Simultaneous bipedicular radiofrequency ablation combined with vertebral augmentation is safe and effective for local tumor control of vertebral metastases. Articulating bipolar electrodes enable the placement and proximity necessary for optimal confluence of the ablation zones. Local tumor control may lead to more durable pain palliation, prevent disease progression, and reduce skeletal-related events of the spine.

Percutaneous Image-Guided Ablation in the Treatment of Osseous Metastases from Non-small Cell Lung Cancer

INTRODUCTION

Percutaneous image-guided ablation is an emerging minimally invasive therapy for patients with metastatic bone disease for whom radiation therapy is ineffective or contraindicated. The purpose of this study was to examine the safety and efficacy of percutaneous ablation in achieving pain palliation and local tumor control of osseous metastases from non-small cell lung cancer (NSCLC).

METHODS

A retrospective review was performed of 76 musculoskeletal metastases in 45 patients treated with percutaneous ablation. 63% (48/76) were treated with radiofrequency ablation (RFA), 35% (27/76) with cryoablation, and 1.3% (1/76) with microwave ablation (MWA). In 70% (53/76) of cases, associated cementoplasty was performed. Primary outcomes measured were pre- and post-procedure pain scores 4 weeks after treatment and local tumor control at 3-, 6-, and 12-month follow-up.

RESULTS

Mean age of the cohort was 63.6 ± 9.5 years. Median tumor diameter was 3.60 cm (range 1.0-10.0 cm). Mean and median pain scores before treatment were 7.5 ± 2.3 and 8.0, respectively. Post-procedure, patients reported significantly decreased pain scores at 4 weeks (mean, 3.7 ± 3.5; median, 3.0; p < 0.00001). Radiographic local tumor control rates were 83% (35/42) at 3 months, 77% (23/30) at 6 months, and 68% (17/25) at 12 months after treatment. The overall complication rate was 2.6% (2/76).

CONCLUSION

Percutaneous tumor ablation is a well-tolerated, minimally invasive procedure associated with improving pain palliation and achieving local tumor control of osseous metastases from NSCLC.

LEVEL OF EVIDENCE

Level 4, case series.

Multicenter clinical and imaging evaluation of targeted radiofrequency ablation (t-RFA) and cement augmentation of neoplastic vertebral lesions

Background

Treatment of spinal metastatic lesions by radiofrequency ablation (RFA) before cementation can potentially help in local tumor control and pain relief. This is often limited by access and tumor location. This study reports multicenter clinical and imaging outcomes following targeted RFA (t-RFA) and cement augmentation in neoplastic lesions of the spine.

Material and methods

A retrospective multicenter study of 49 patients with 72 painful vertebral lesions, evaluated for clinical and imaging outcomes following RFA and cement augmentation of spinal metastatic lesions, was undertaken. Visual Analogue Pain score (VAS) and Oswestry Disability Index (ODI) were obtained before and 2–4 weeks after treatment. Pre- and post-procedure imaging examinations including MRI and positron emission tomography (PET) were also evaluated.

Results

Mean ablation time was 3.7±2.5 min (range 0.92–15). Mean VAS scores decreased from 7.9±2.5 pre-procedure to 3.5±2.6 post-procedure (p<0.0001). Mean ODI scores improved from 34.9±18.3 to 21.6±13.8 post-procedure (p<0.0001). Post-contrast MRI resulted in a predictable pattern of decreased tumor volume and an enhancing rim. Metabolically active lesions in pre-procedure PET scans (n=10 levels) showed decreased fluorodeoxyglucose activity after ablation.

Conclusions

t-RFA followed by vertebral augmentation in malignant vertebral lesions resulted in significant pain reduction and functional status improvement, with no major complications. t-RFA permitted access to vertebral lesions and real-time accurate monitoring of the ablation zone temperature. Post-procedure MRI and PET examinations correlated with a favorable tumor response and helped to monitor tumor growth and the timing of adjuvant therapy.

Expanding role of percutaneous ablative and consolidative treatments for musculoskeletal tumours

Interventional approaches to musculoskeletal tumours have significantly changed over the last several years, and new treatments continue to be developed. All ablative modalities are currently applied to the treatment of bone tumours, including radiofrequency, cryo-, microwave, and laser ablation devices. Indications for ablation of bone and soft-tissue tumours have expanded beyond palliation of painful bone metastases and eradication of osteoid osteomas to the local control of oligometastatic disease from a number of primary tumours and ablation of desmoid tumours. In addition, tools for consolidation of bone tumours at risk of pathological fracture have also expanded. With these developments, ablation has become the primary treatment for osteoid osteomas and, at some institutions, desmoid tumours. It may be the primary or secondary treatment for palliation of painful bone tumours, frequently used in patients with pain refractory to or recurrent after radiation therapy. It is used as a treatment for limited metastatic disease or for metastases that grow disproportionately in patients with multifocal metastases, either in combination with systemic therapy or to reserve systemic therapy and its toxicity for more widespread disease progression. Moreover, percutaneous methods to consolidate bone at risk of fracture have become more commonplace, aided by techniques using materials beyond typical bone cement.

Treatment of osseous metastases using the Spinal Tumor Ablation with Radiofrequency (STAR) system

INTRODUCTION

Percutaneous ablation is an emerging, minimally invasive therapy for patients with osseous metastases who have not responded or have contraindications to radiation therapy. Goals of therapy are pain relief, and in some cases, prevention of local tumor progression. Areas covered: The epidemiology, pathophysiology, natural history, and traditional management of metastatic bone disease are reviewed. Novel features of the Spinal Tumor Ablation with Radiofrequency (STAR) System (DFINE, San Jose, CA) that facilitate treatment of osseous metastases are described, including the bipolar electrode, extensible distal tip that can be curved up to 90°, and inclusion of thermocouples that enable real-time monitoring of the ablation zone volume. Lastly, research evaluating the safety and efficacy of using this device to treat musculoskeletal metastases is summarized. Expert commentary: Although evidence supporting the efficacy of RFA for the treatment of bone metastases is limited to case series, it is a reasonable therapy when other options have been exhausted, especially given the safety and minimal morbidity of the procedure. The STAR Tumor Ablation System has expanded the anatomic scope of bone metastases that can be safely and effectively treated with percutaneous ablation.

Radiofrequency ablation alone or in combination with cementoplasty for local control and pain palliation of sacral metastases: preliminary results in 11 patients

PURPOSE

To determine the safety and effectiveness of radiofrequency ablation (RFA) to treat sacral metastases for pain palliation and local tumor control (LTC).

MATERIALS AND METHODS

An institutional tumor ablation registry was retrospectively reviewed for sacral RFA procedures performed between January 2012 and December 2015. Clinical history, pre-procedural imaging, and procedural details were reviewed to document indication for treatment, primary tumor histology, tumor volumes, presence of concurrent cementoplasty after RFA, and the occurrence of peri-procedural complications. Pain scores before and 4 weeks after the procedure were recorded. Post-procedure imaging was reviewed for imaging evidence of tumor progression. Long-term complications and duration of clinical follow-up were recorded.

RESULTS

During the study period, 11 RFA procedures were performed to treat 16 sacral metastases. All procedures were for pain palliation. Four procedures (36 %; 4 out of 11) were also performed with the intention of achieving LTC in patients with oligometastatic disease. Concurrent cementoplasty was performed in 63 % of cases (7 out of 11). The median pain score decreased from 8 (interquartile range, 6-9.25) at baseline to 3 (interquartile range, 1.75-6.3) 1 month following RFA (P = 0.004). In the 4 patients with oligometastatic disease, LTC was achieved in 3 patients (75 %; 3 out of 4) after a median follow-up of 7.6 months (range, 3.6-11.9 months). No acute or long-term complications were documented during the overall median clinical follow-up of 4.7 months (range, 0.9-28.7 months).

CONCLUSIONS

Radiofrequency ablation maybe a safe and potentially effective treatment for patients with painful sacral metastases and can achieve LTC in selected patients.

Image-Guided Spinal Ablation: A Review

The image-guided thermal ablation procedures can be used to treat a variety of benign and malignant spinal tumours. Small size osteoid osteoma can be treated with laser or radiofrequency. Larger tumours (osteoblastoma, aneurysmal bone cyst and metastasis) can be addressed with radiofrequency or cryoablation. Results on the literature of spinal microwave ablation are scarce, and thus it should be used with caution. A distinct advantage of cryoablation is the ability to monitor the ice-ball by intermittent CT or MRI. The different thermal insulation, temperature and electrophysiological monitoring techniques should be applied. Cautious pre-procedural planning and intermittent intra-procedural monitoring of the ablation zone can help reduce neural complications. Tumour histology, patient clinical-functional status and life-expectancy should define the most efficient and least disabling treatment option.

Percutaneous Image-Guided Musculoskeletal Tumor Treatments

OBJECTIVE

The purpose of this article is to review the current guidelines and recommendations for percutaneous image-guided treatment of musculoskeletal tumors.

CONCLUSION

With the ongoing technologic advances, it is essential that the musculoskeletal interventionalist is familiar with the current tools and techniques available for the treatment of soft-tissue and bone tumors. Fortunately, many of these tools are readily available in a standard interventional radiology department and can be easily applied to the musculoskeletal system.

Radiographic Local Control of Spinal Metastases with Percutaneous Radiofrequency Ablation and Vertebral Augmentation

BACKGROUND AND PURPOSE

Combination radiofrequency ablation and vertebral augmentation is an emerging minimally invasive therapy for patients with metastatic spine disease who have not responded to or have contraindications to radiation therapy. The purpose of this study was to evaluate the rate of radiographic local control of spinal metastases treated with combination radiofrequency ablation and vertebral augmentation.

MATERIALS AND METHODS

We retrospectively reviewed our tumor ablation database for all patients who underwent radiofrequency ablation and vertebral augmentation of spinal metastases between April 2012 and July 2014. Tumors treated in conjunction with radiation therapy were excluded. Tumor characteristics, procedural details, and complications were recorded. Posttreatment imaging was reviewed for radiographic evidence of tumor progression.

RESULTS

Fifty-five tumors met study inclusion criteria. Radiographic local tumor control rates were 89% (41/46) at 3 months, 74% (26/35) at 6 months, and 70% (21/30) at 1 year after treatment. Clinical follow-up was available in 93% (51/55) of cases. The median duration of clinical follow-up was 34 weeks (interquartile range, 15-89 weeks), during which no complications were reported and no patients had clinical evidence of metastatic spinal cord compression at the treated levels.

CONCLUSIONS

Combination radiofrequency ablation and vertebral augmentation appears to be an effective treatment for achieving local control of spinal metastases. A prospective clinical trial is now needed to replicate these results.

Combination acetabular radiofrequency ablation and cementoplasty using a navigational radiofrequency ablation device and ultrahigh viscosity cement: technical note

BACKGROUND

Percutaneous radiofrequency ablation and cementoplasty is an alternative palliative therapy for painful metastases involving axial load-bearing bones. This technical report describes the use of a navigational radiofrequency probe to ablate acetabular metastases from an anterior approach followed by instillation of ultrahigh viscosity cement under CT-fluoroscopic guidance.

MATERIALS AND METHODS

The tumor ablation databases of two institutions were retrospectively reviewed to identify patients who underwent combination acetabular radiofrequency ablation and cementoplasty using the STAR Tumor Ablation and StabiliT Vertebral Augmentation Systems (DFINE; San Jose, CA). Pre-procedure acetabular tumor volume was measured on cross-sectional imaging. Pre- and post-procedure pain scores were measured using the Numeric Rating Scale (10-point scale) and compared. Partial pain improvement was categorically defined as ≥ 2-point pain score reduction. Patients were evaluated for evidence of immediate complications. Electronic medical records were reviewed for evidence of delayed complications.

RESULTS

During the study period, 12 patients with acetabular metastases were treated. The median tumor volume was 54.3 mL (range, 28.3-109.8 mL). Pre- and post-procedure pain scores were obtained from 92% (11/12) of the cohort. The median pre-procedure pain score was 8 (range, 3-10). Post-procedure pain scores were obtained 7 days (82%; 9/11), 11 days (9.1%; 1/11) or 21 days (9.1%; 1/11) after treatment. The median post-treatment pain score was 3 (range, 1-8), a statistically significant difference compared with pre-treatment (P = 0.002). Categorically, 73% (8/11) of patients reported partial pain relief after treatment. No immediate symptomatic complications occurred. Three patients (25%; 3/12) were discharged to hospice within 1 week of treatment. No delayed complications occurred in the remaining 75% (9/12) of patients during median clinical follow-up of 62 days (range, 14-178 days).

CONCLUSIONS

Palliative percutaneous acetabular radiofrequency ablation and cementoplasty can be feasibly performed from an anterior approach using a navigational ablation probe and ultrahigh viscosity cement instilled under CT-fluoroscopic guidance.

Spine Cryoablation: Pain Palliation and Local Tumor Control for Vertebral Metastases

BACKGROUND AND PURPOSE

Percutaneous cryoablation has emerged as a minimally invasive technique for the management of osseous metastases. The purpose of this study was to assess the safety and effectiveness of percutaneous imaging-guided spine cryoablation for pain palliation and local tumor control for vertebral metastases.

MATERIALS AND METHODS

Imaging-guided spine cryoablation was performed in 14 patients (31 tumors) with vertebral metastases refractory to conventional chemoradiation therapy or analgesics, to achieve pain palliation and local tumor control in this retrospective study. Spinal nerve and soft-tissue thermal protection techniques were implemented in all ablations. Patient response was evaluated by a pain numeric rating scale administered before the procedure and 1 week, 1 month, and 3 months after the procedure. Pre- and postprocedural analgesic requirements (expressed as morphine-equivalent dosages) were also analyzed at the same time points. Pre- and postprocedural cross-sectional imaging was evaluated in all patients to assess local control (no radiographic evidence of disease at the treated sites). Complications were monitored. Analysis of the primary end points was undertaken via paired-comparison procedures by using the Wilcoxon signed rank test.

RESULTS

Thirty-one tumors were ablated in 14 patients (9 women and 5 men; 20-73 years of age; mean age, 53 years). The most common tumor location was in the lumbar spine (n = 14, 45%), followed by the thoracic spine (n = 8, 26%), sacrum (n = 6, 19%), coccyx (n = 2, 6%), and cervical spine (n = 1, 3%). There were statistically significant decreases in the median numeric rating scale score and analgesic usage at 1-week, 1-month, and 3-month time points (P < .001 for all). Local tumor control was achieved in 96.7% (30/31) of tumors (median follow-up, 10 months). Two patients had transient postprocedural unilateral lower extremity radiculopathy and weakness.

CONCLUSIONS

Percutaneous imaging-guided spine cryoablation is a safe and effective treatment for pain palliation and local tumor control for vertebral metastases.

Treatment of Osteoid Osteomas Using a Navigational Bipolar Radiofrequency Ablation System

BACKGROUND

Percutaneous CT-guided radiofrequency ablation is a safe and effective minimally invasive treatment for osteoid osteomas. This technical case series describes the use of a recently introduced ablation system with a probe that can be curved in multiple directions, embedded thermocouples for real-time monitoring of the ablation volume, and a bipolar design that obviates the need for a grounding pad.

METHODS

Medical records of all patients who underwent radiofrequency ablation of an osteoid osteoma with the STAR Tumor Ablation System (DFINE; San Jose, CA) were reviewed. The location of each osteoid osteoma, nidus volume, and procedural details were recorded. Treatment efficacy and long-term complications were assessed at clinical follow-up.

RESULTS

During the study period, 18 osteoid osteomas were radiofrequency ablated with the multidirectional bipolar system. Lesion locations included the femur (50%; 9/18), tibia (22%; 4/18), cervical spine (11%; 2/18), calcaneus (5.5%; 1/18), iliac bone (5.5%; 1/18), and fibula (5.5%; 1/18). The median nidus volume of these cases was 0.33 mL (range 0.12-2.0 mL). All tumors were accessed via a single osseous channel. Median cumulative ablation time was 5 min and 0 s (range 1 min and 32 s-8 min and 50 s). All patients with clinical follow-up reported complete symptom resolution. No complications occurred.

CONCLUSION

Safe and effective CT-guided radiofrequency ablation of osteoid osteomas can be performed in a variety of locations using a multidirectional bipolar system.

Delayed vertebral body collapse after stereotactic radiosurgery and radiofrequency ablation: Case report with histopathologic-MRI correlation

Stereotactic radiosurgery and percutaneous radiofrequency ablation are emerging therapies for pain palliation and local control of spinal metastases. However, the post-treatment imaging findings are not well characterized and the risk of long-term complications is unknown. We present the case of a 46-year-old woman with delayed vertebral body collapse after stereotactic radiosurgery and radiofrequency ablation of a painful lumbar metastasis. Histopathologic-MRI correlation confirmed osteonecrosis as the underlying etiology and demonstrated that treatment-induced vascular fibrosis and tumor progression can have identical imaging appearances.

The Metastatic Spine Disease Multidisciplinary Working Group Algorithms

The Metastatic Spine Disease Multidisciplinary Working Group consists of medical and radiation oncologists, surgeons, and interventional radiologists from multiple comprehensive cancer centers who have developed evidence- and expert opinion-based algorithms for managing metastatic spine disease. The purpose of these algorithms is to facilitate interdisciplinary referrals by providing physicians with straightforward recommendations regarding the use of available treatment options, including emerging modalities such as stereotactic body radiation therapy and percutaneous tumor ablation. This consensus document details the evidence supporting the Working Group algorithms and includes illustrative cases to demonstrate how the algorithms may be applied.

Drill-assisted, fluoroscopy-guided vertebral body access for radiofrequency ablation: Technical case series

Radiofrequency ablation is a valuable therapy for palliation of painful spinal metastases and local tumor control; however, accessing the vertebral body can be difficult and time consuming with traditional manual needles. Herein, we report our initial experience using a drill-assisted, fluoroscopy-guided technique for accessing the vertebral body for radiofrequency ablation.