Radiofrequency ablation of spinal tumors: temperature distribution in the spinal canal

Image-Guided Minimally Invasive Treatment Options for Degenerative Lumbar Spine Disease: A Practical Overview of Current Possibilities

Lumbar back pain is one of the main causes of disability around the world. Most patients will complain of back pain at least once in their lifetime. The degenerative spine is considered the main cause and is extremely common in the elderly population. Consequently, treatment-related costs are a major burden to the healthcare system in developed and undeveloped countries. After the failure of conservative treatments or to avoid daily chronic drug intake, invasive treatments should be suggested. In a world where many patients reject surgery and prefer minimally invasive procedures, interventional radiology is pivotal in pain management and could represent a bridge between medical therapy and surgical treatment. We herein report the different image-guided procedures that can be used to manage degenerative spine-related low back pain. Particularly, we will focus on indications, different techniques, and treatment outcomes reported in the literature. This literature review focuses on the different minimally invasive percutaneous treatments currently available, underlining the central role of radiologists having the capability to use high-end imaging technology for diagnosis and subsequent treatment, allowing a global approach, reducing unnecessary surgeries and prolonged pain-reliever drug intake with their consequent related complications, improving patients' quality of life, and reducing the economic burden.

Essentials of Spinal Tumor Ablation

Recent advances in percutaneous minimally invasive thermal ablation and vertebral augmentation provide radiologists with important arsenal for treatment of selected patients with spinal metastases. These interventions have proven to be safe, effective, and durable in treatment of selected patients with vertebral metastases. Attention to procedure techniques, including choice of ablation modality, vertebral augmentation technique, and thermal protection, is essential for improved patient outcomes. A detailed knowledge of such interventions and implementation of procedural safety measures will further heighten radiologists' role in the management of patients with spinal metastases.

Benign Bone Tumors Beyond Osteoid Osteoma: Percutaneous Minimally Invasive Image-Guided Interventions

Painful benign bone tumors often adversely influence quality of life primarily due to skeletal-related events such as unremittable pain, pathologic fracture, neurologic deficit, as well as skeletal growth disturbance. Substantial advances in percutaneous minimally invasive interventions for treatment of painful benign bone tumors beyond osteoid osteoma have been established as safe, efficacious, and durable treatments to achieve definitive cure. This article details the available armamentarium and most recent advances in minimally invasive percutaneous interventions and the role of radiologists for the management of patients with benign bone tumors beyond osteoid osteoma.

Musculoskeletal Interventional Oncology: A Contemporary Review

Musculoskeletal interventional oncology is an emerging field that addresses the limitations of conventional therapies for bone and soft-tissue tumors. The field's growth has been driven by evolving treatment paradigms, expanding society guidelines, mounting supportive literature, technologic advances, and cross-specialty collaboration with medical, surgical, and radiation oncology. Safe, effective, and durable pain palliation, local control, and stabilization of musculoskeletal tumors are increasingly achieved through an expanding array of contemporary minimally invasive percutaneous image-guided treatments, including ablation, osteoplasty, vertebral augmentation (with or without mechanical reinforcement via implants), osseous consolidation via percutaneous screw fixation (with or without osteoplasty), tumor embolization, and neurolysis. These interventions may be used for curative or palliative indications and can be readily combined with systemic therapies. Therapeutic approaches include the combination of different interventional oncology techniques as well as the sequential application of such techniques with other local treatments, including surgery or radiation. This article reviews the current practice of interventional oncology treatments for the management of patients with bone and soft-tissue tumors with a focus on emerging technologies and techniques.

Heat treatment for giant cell tumors of bone: A systematic review

This systematic review evaluates the effects of heat treatments in de novo, residual and recurrent giant cell tumors of bone (GCTB). Studies were eligible for inclusion if one of the following treatments was administered: radiofrequency ablation (RFA), microwave ablation, argon cauterization, electrocauterization and hot liquid treatment. The primary outcome was recurrence. Secondary outcomes were complications, pain, function, and quality of life. Recurrence rates for microwave ablation as an adjuvant to intralesional curettage were 0%, 4% and 10% (3 retrospective single-group studies); for argon cauterization 4%, 8% and 26% (3 cohort studies); electrocauterization 0% to 33% (8 cohort studies); and hot liquid 9.5% and 24% (2 cohort studies). Follow-up was generally ≥24 months. Data on pain, function and quality of life were scarce. Complications included infection and secondary osteoarthritis. Current evidence does not demonstrate or exclude an effect of heat treatments on recurrence in GCTB. Further research should objectify if (subgroups of) patients benefit from these treatments.

Percutaneous Treatment of Spinal Metastases

Percutaneous image-guided minimally invasive thermal ablation and vertebral augmentation are robust techniques, part of the available armamentarium used by radiologists for the management of patients with spinal metastases. Such interventions have been established to be safe and effective in treatment of selected patients with vertebral metastases. Special attention to procedure techniques including choice of ablation modality, vertebral augmentation technique, and thermal protection is essential for improved patient outcomes.

Benign Bone Tumors: State of the Art in Minimally Invasive Percutaneous Interventions

Painful benign bone tumors most commonly affect pediatric patients and young adults. They may be associated with skeletal-related events such as intractable pain, pathologic fracture, neurologic deficit as a consequence of nerve or spinal cord compression, as well as growth disturbance. Consequently, they often result in diminished activity and adversely affect quality of life. There have been substantial recent advances in percutaneous minimally invasive image-guided interventions for treatment of painful benign bone tumors including thermal ablation (radiofrequency ablation, cryoablation, microwave ablation, laser photocoagulation, and high-intensity focused US ablation), chemical (alcohol) ablation, cementoplasty, and intralesional injections. The safety, efficacy, and durability of such interventions have been established in the recent literature and as such, the role of musculoskeletal interventional radiologists in the care of patients with benign bone lesions has substantially expanded. The treatment goal of minimally invasive musculoskeletal interventions in patients with benign bone tumors is to achieve definitive cure. The authors detail the most recent advances and available armamentarium in minimally invasive image-guided percutaneous interventions with curative intent for the management of benign bone tumors. ^© RSNA, 2022.

Minimally Invasive Resection of Benign Osseous Tumors of the Spinal Column: 10 Years' Experience and Long-Term Outcomes of a Specialized Center

Background and Objectives: Benign osseous tumors of the spinal column comprise about 10% of all spinal tumors and are rare cause for surgery. However, these tumors pose various management challenges and conventional surgery may be associated with significant morbidity. Previous reports on minimally invasive resection of these lesions are rare. We report a series of patients managed by total resection of benign osseous spine tumors using MIS techniques. Surgical decisions and technical considerations are discussed. Materials and Methods: A retrospective evaluation of prospectively collected data of patients who underwent minimally invasive surgery for removal of benign osseous vertebral tumors. Demographic, clinical and radiographic features, operative details and final pathological reports were summarized. Primary outcomes were completeness of tumor resection and pain relief assessed by VAS for back and leg pain. Secondary outcome measures were recurrence of tumor on repeat post-operative MRI and postoperative unstable deformity on standing scoliosis X-rays. Results: This series included 32 cases of primary osseous spine tumors resected by minimally invasive techniques. There were 17 males and 15 females aged 5-68 years (mean 23.3). The follow-up period was 8-90 months (mean 32 months) and the preoperative symptoms duration was 9-96 months. Axial spinal pain was the presenting symptom in all the patients. Five patients also complained about radicular pain and four patients had antalgic scoliosis. The tumor involved the thoracic spine in 12 cases, the lumbar segment in 11, the cervical in 5 and the sacral area in 4 cases. Complete tumor removal was performed in all patients. No procedure-related complications were encountered. Histopathology showed osteoid osteoma in 24 patients, osteoblastoma in 5 patients, and fibrous dysplasia, fibroadenoma and eosinophilic granuloma in one case each. All patients experienced significant pain relief after surgery, and had stopped pain medications by 12 months postoperatively. No patient suffered from tumor recurrence or spinal deformity. Conclusions: Minimally invasive surgery is feasible for total removal of selected benign vertebral tumors and may have some advantages over conventional surgical techniques.

Radiofrequency Ablation and Augmentation in the Management of Spinal Metastases: Clinical Experience in 41 Patients

OBJECTIVE

To evaluate functional outcome after combined radiofrequency ablation and vertebral augmentation in patients with metastatic spinal tumors using visual analog scale and Oswestry Disability Index scores.

METHODS

This retrospective study included 41 patients with metastatic spinal tumors. There were 19 women and 22 men with a mean age of 67 years (range, 45-87 years). Visual analog scale and Oswestry Disability Index were used to assess the intensity of pain and quality of life. The assessments were performed before the procedure and at 1 week and 1, 2, 3, and 6 months after the procedure.

RESULTS

No serious complications were seen in the periprocedural period. Two patients (4.8%) had transient neurological motor deficits without cement leakage, and 1 patient had a pulmonary embolism with transient mild symptoms. The comparison of preprocedural visual analog scale and Oswestry Disability Index scores with postprocedural scores up to 6 months after treatment revealed significant pain control and good functional state.

CONCLUSIONS

Spinal metastasis is a frequent entity in the growing population of patients with cancer. A multidisciplinary approach using several nonsurgical and minimally invasive methods (e.g., radiofrequency ablation, vertebroplasty, balloon kyphoplasty) is key to successful management, and combining these procedures is effective against spinal metastatic pain.

Interventional Palliation of Painful Extraspinal Musculoskeletal Metastases

The musculoskeletal system is commonly involved by metastases, and skeletal-related events such as intractable pain due to direct osseous tumor involvement, pathologic fracture, and neurologic deficits as a result of nerve compression often adversely affect patient's quality of life. There have been substantial advances in percutaneous minimally invasive musculoskeletal oncologic interventions for the management of patients with musculoskeletal metastases including thermal ablations, cementation with or without osseous reinforcement via implants, osteosynthesis, neurolysis, and palliative injections which are progressively incorporated in clinical practice. These interventions are performed, in conjunction with or supplemented by adjuvant radiation therapy, systemic therapy, surgery, or analgesics, to achieve durable pain palliation, local tumor control, or cure. This article reviews minimally invasive percutaneous image-guided musculoskeletal oncologic interventions for the management of patients with extraspinal musculoskeletal metastases.

Thermal Protection Strategies and Neuromonitoring during Ablation

Advanced interventional pain management approaches seek to lesion neural targets to achieve desirable analgesia; however, equally important is preservation of motor and sensory function for regional bystander nerves. The topic of neuroprotection is also relevant for thermal ablation of metastatic bone tumors in the vicinity of neural structures. This report aims to provide an IR-directed framework of thermoprotective techniques available during thermal ablation.

Microwave Ablation of Spinal Osteoid Osteoma—Role of Air Insulation

Osteoid osteomas are benign tumors seen in children and young adults. The management options include surgical resection and percutaneous ablation. In the present scenario, percutaneous ablation is the preferred modality, as it is minimally invasive, safe, and reliable. However, when the tumor is near a heat-vulnerable structure, thermal injury can occur.

We report the case of spinal osteoid osteoma in a young female that was treated by microwave ablation (MWA) with air insulation to prevent heat injury to the spinal cord. Currently, there is paucity of literature describing the use of air insulation with MWA. In this report, we describe the technique, advantages, and limitations of using air insulation with MWA.

Management of Osteoblastoma and Giant Osteoid Osteoma with Percutaneous Thermoablation Techniques

Osteoblastoma (OB) is a rare, benign bone tumor, accounting for 1% of all primary bone tumors, which occurs usually in childhood and adolescence. OB is histologically and clinically similar to osteoid osteoma (OO), but it differs in size. It is biologically more aggressive and can infiltrate extraskeletal tissues. Therapy is required because of severe bone pain worsening at night. Moreover, non-steroid anti-inflammatory drugs (NSAIDs) are not a reasonable long-term treatment option in young patients. Surgical excision, considered the gold standard in the past, is no longer attractive today due to its invasiveness and the difficulty in performing a complete resection. The treatment of choice is currently represented by percutaneous thermoablation techniques. Among these, Radiofrequency ablation (RFA) is considered the gold standard treatment, even when the lesions are located in the spine. RFA is a widely available technique that has shown high efficacy and low complication rates in many studies. Other percutaneous thermoablation techniques have been used for the treatment of OB, including Cryoablation (CA) and laser-ablation (LA) with high success rates and low complications. Nevertheless, their role is limited, and further studies are necessary.

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.

Bone Metastases: State of the Art in Minimally Invasive Interventional Oncology

Bone is the third most common site involved by cancer metastases, and skeleton-related events such as intractable pain due to direct osseous tumor involvement, pathologic fracture, and neurologic deficits as a consequence of nerve or spinal cord compression often affect patients' functional independence and quality of life unfavorably. The annual medical-economic burden related to bone metastases is a substantial component of the total direct medical cost estimated by the National Institutes of Health. There have been substantial recent advances in percutaneous image-guided minimally invasive musculoskeletal oncologic interventions for the management of patients with osseous metastatic disease. These advances include thermal ablation, cementation with or without osseous reinforcement with implants, osteosynthesis, thermal and chemical neurolyses, and palliative injections, which are progressively incorporated into the management paradigm for such patients. These interventions are performed in conjunction with or are supplemented by adjuvant radiation therapy, systemic therapy, surgery, or analgesic agents to achieve durable pain palliation, local tumor control, or cure, and they provide a robust armamentarium for interventional radiologists to achieve safe and effective treatment in a multidisciplinary setting. In addition, these procedures are shifting the patient management paradigm in modern-era practice. The authors detail the state of the art in minimally invasive percutaneous image-guided musculoskeletal oncologic interventions and the role of radiologists in managing patients with skeletal metastases. ^©RSNA, 2021.

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.

Resection of Benign Osseous Spine Tumors in Pediatric Patients by Minimally Invasive Techniques

OBJECTIVE

Benign osseous tumors of the spine in children are a rare cause for surgery. The aim of this study is to describe our experience with resection of pediatric benign osseous spine tumors using a minimally invasive technique through a variety of surgical approaches.

METHODS

A retrospective review of prospectively collected data of pediatric patients who underwent minimally invasive resection of a benign osseous vertebral tumor from May 2013 through November 2018 was performed. Primary outcome measures included the extent of resection and pain resolution. Secondary outcomes included postoperative spinal instability evaluated by standing scoliosis x-rays and tumor recurrence evaluated by periodic follow-up magnetic resonance imaging scans.

RESULTS

Our study group comprised 8 children, 3 males and 5 females, with a mean age of 12.2 years. The average follow-up period was 4.3 years. Complete removal of tumors was achieved in all cases and was verified by follow-up magnetic resonance imaging scans. There were no procedure-related complications. The average duration of surgery was 70 minutes, and the blood loss was less than 20 cc in all cases. The average inpatient length of stay was 1.6 days. Histopathology revealed osteoid osteoma in 6 patients and osteoblastoma in 2 patients. Average improvement of the pain scores was from 8 to 0.8. At the time of this report, no tumor recurrence was evident in all 8 patients and none of the cases developed spinal deformity.

CONCLUSION

Our limited experience suggests that the minimally invasive technique is a valuable option for the surgical management of selected benign osseous spinal tumors in children.

Techniques for Temperature Monitoring of Myocardial Tissue Undergoing Radiofrequency Ablation Treatments: An Overview

Cardiac radiofrequency ablation (RFA) has received substantial attention for the treatment of multiple arrhythmias. In this scenario, there is an ever-growing demand for monitoring the temperature trend inside the tissue as it may allow an accurate control of the treatment effects, with a consequent improvement of the clinical outcomes. There are many methods for monitoring temperature in tissues undergoing RFA, which can be divided into invasive and non-invasive. This paper aims to provide an overview of the currently available techniques for temperature detection in this clinical scenario. Firstly, we describe the heat generation during RFA, then we report the principle of work of the most popular thermometric techniques and their features. Finally, we introduce their main applications in the field of cardiac RFA to explore the applicability in clinical settings of each method.

Fluid Lubrication and Cooling Effects in Diamond Grinding of Human Iliac Bone

Background and Objectives: Although there have been research on bone cutting, there have been few research on bone grinding. This study reports the measurement results of the experimental system that simulated partial laminectomy in microscopic spine surgery. The purpose of this study was to examine the fluid lubrication and cooling in bone grinding, histological characteristics of workpieces, and differences in grinding between manual and milling machines. Materials and Methods: Thiel-fixed human iliac bones were used as workpieces. A neurosurgical microdrill was used as a drill system. The workpieces were fixed to a 4-component piezo-electric dynamometer and fixtures, which was used to measure the triaxial power during bone grinding. Grinding tasks were performed by manual activity and a small milling machine with or without water. Results: In bone grinding with 4-mm diameter diamond burs and water, reduction in the number of sudden increases in grinding resistance and cooling effect of over 100 °C were confirmed. Conclusion: Manual grinding may enable the control of the grinding speed and cutting depth while giving top priority to uniform torque on the work piece applied by tools. Observing the drill tip using a triaxial dynamometer in the quantification of surgery may provide useful data for the development of safety mechanisms to prevent a sudden deviation of the drill tip.

Combinatorial effect of radium-223 and irreversible electroporation on prostate cancer bone metastasis in mice

BACKGROUND

Metastatic prostate cancer in bone is difficult to treat as the tumor cells are relatively resistant to hormonal or chemotherapies when compared to primary prostate cancer. Irreversible electroporation (IRE) is a minimally invasive ablation procedure that has potential applications in the management of prostate cancer in bone. However, a common limitation of IRE is tumor recurrence, which arises from incomplete ablation that allows remaining cancer cells to proliferate. In this study, we combined IRE with radium-223 (Ra-223), a bone-seeking radionuclide that emits short track length alpha particles and thus is associated with reduced damage to the bone marrow and evaluated the impact of the combination treatment on bone-forming prostate cancer tumors.

METHODS

The antitumor activity of IRE and Ra-223 as single agents and in combination was tested in vitro against three bone morphogenetic protein 4 (BMP4)-expressing prostate cancer cell lines (C4-2B-BMP4, Myc-CaP-BMP4, and TRAMP-C2-BMP4). Similar evaluation was performed in vivo using a bone-forming C4-2B-BMP4 tumor model in nude mice.

RESULTS

IRE and Ra-223 as monotherapy inhibited prostate cancer cell proliferation in vitro, and their combination resulted in significant reduction in cell viability compared to monotherapy. In vivo evaluation revealed that IRE with single-dose administration of Ra-233, compared to IRE alone, reduced the rate of tumor recurrence by 40% following initial apparent complete ablation and decreased the rate of proliferation of incompletely ablated tumor as quantified in Ki-67 staining (53.58 ± 16.0% for IRE vs. 20.12 ± 1.63%; for IRE plus Ra-223; p = 0.004). Histological analysis qualitatively showed the enhanced killing of tumor cells adjacent to bone by Ra-223 compared to those treated with IRE alone.

CONCLUSION

IRE in combination with Ra-223, which enhanced the destruction of cancer cells that are adjacent to bone, resulted in reduction of tumor recurrence through improved clearance of proliferative cells in the tumor region.

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.

Surgery Versus Radiofrequency Ablation in the Management of Spinal Osteoid Osteomas: A Spine Oncology Referral Center Comparison Analysis of 138 Cases

BACKGROUND

Osteoid osteomas (OOs) are benign bone forming tumors that, usually, occur in the extremities, with about 10% of them arising in the spine more commonly in the posterior elements. The aim of this study is to evaluate the long-term results of patients suffering from spinal OO treated with surgery and radiofrequency ablation.

METHODS

This was a retrospective comparison analysis of data prospectively collected from 2 cohorts of consecutive patients diagnosed with OO of the spine treated at the same Institute from November 2002 to February 2019. The first cohort included patients submitted to an intralesional extracapsular excision of the lesion (surgery group); the second cohort included patients submitted to radiofrequency ablation (RFA group).

RESULTS

The surgery group showed a local recurrence rate of 1.7% versus a recurrence rate of 12.5% in the RFA group with a statistically significant difference in the disease-free survival at longest follow-up (P = 0.012). No statistically significant differences were observed in local recurrence rate stratified for level and site of lesion. No complications were observed in both groups at the time of first procedure.

CONCLUSIONS

Surgery and RFA are both safe and effective interventional procedures for the management of spinal OO, although RFA is associated with a greater recurrence rate. Treatment should be tailored according to the relationship of lesions with neural structures and to advantages and disadvantages of each technique.

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.

The Role of Minimal Access Surgery in the Treatment of Spinal Metastatic Tumors

STUDY DESIGN

Literature review.

OBJECTIVE

To provide an overview of the recent advances in minimal access surgery (MAS) for spinal metastases.

METHODS

Literature review.

RESULTS

Experience gained from MAS in the trauma, degenerative and deformity settings has paved the road for MAS techniques for spinal cancer. Current MAS techniques for the treatment of spinal metastases include percutaneous instrumentation, mini-open approaches for decompression and tumor resection with or without tubular/expandable retractors and thoracoscopy/endoscopy. Cancer care requires a multidisciplinary effort and adherence to treatment algorithms facilitates decision making, ultimately improving patient outcomes. Specific algorithms exist to help guide decisions for MAS for extradural spinal metastases. One major paradigm shift has been the implementation of percutaneous stabilization for treatment of neoplastic spinal instability. Percutaneous stabilization can be enhanced with cement augmentation for increased durability and pain palliation. Unlike osteoporotic fractures, kyphoplasty and vertebroplasty are known to be effective therapies for symptomatic pathologic compression fractures as supported by high level evidence. The integration of systemic body radiation therapy for spinal metastases has eliminated the need for aggressive tumor resection allowing implementation of MAS epidural tumor decompression via tubular or expandable retractors and preliminary data exist regarding laser interstitial thermal therapy and radiofrequency ablation for tumor control. Neuronavigation and robotic systems offer increased precision, facilitating the role of MAS for spinal metastases.

CONCLUSIONS

MAS has a significant role in the treatment of spinal metastases. This review highlights the current utilization of minimally invasive surgical strategies for treatment of spinal metastases.

Retrospective analysis of CT-guided percutaneous cryoablation for treatment of painful osteolytic bone metastasis

This study aimed to evaluate the safety and effectiveness of CT-guided percutaneous cryoablation for treatment of painful osteolytic bone metastases. A total of 26 patients (36 bone metastases) treated with CT-guided percutaneous cryoablation between May 2012 and June 2016 were enrolled in this retrospective study. All procedures were performed under local anesthesia. A visual analog scale (VAS) was used to evaluate pain before the procedure and at 1 day, 1 month, 3 months, and 6 months after the procedure. Complications during and after the procedure were recorded and graded by the Clavien-Dindo classification. The mean VAS pain score was 7.1 ± 1.1 (range, 4-10) before cryoablation. It was significantly lower at all timepoints after treatment: 2.1 ± 1.7 (P < 0.0001) at 1 day after treatment, 1.3 ± 1.8 (P < 0.0001) at 1 month, 1.6 ± 1.7 (P < 0.0001) at 3 months, and 1.8 ± 1.3 (P < 0.0001) at 6 months. The response rates were 91.7%, 94.4%, 91.7%, and 94.4%, respectively, at 1 day, 1 month, 3 months, and 6 months after cryoablation; the complete response rates were 22.2%, 41.7%, 36.1%, and 22.2%, respectively. Adverse events (skin frostbite, nerve injury, pathologic fracture) occurred in 3 patients. CT-guided percutaneous cryoablation under local anesthesia appears to be a safe and effective treatment for painful osteolytic bone metastases. Prospective clinical trials on large samples needed to confirm this conclusion.

Percutaneous Interventional Management of Spinal Metastasis

Spinal metastasis is usually associated with debilitating pain and results in deteriorating life quality. The role of percutaneous management of spinal metastasis has evolved from a diagnostic role to a significant part of therapeutic options in conjunction with conventional management techniques, including radiotherapy and open surgical options. Percutaneous vertebral augmentation (PVA) showed substantial pain reduction, vertebral stabilization, and improvement of quality of life. Minimally invasive local ablative procedures (MILAPs) demonstrated significant pain reduction, local tumor burden control, and improvement of quality of life. Though combined PVA and MILAP's synergistic role in pain reduction may need additional investigation, considering different actions on spine metastasis patients, combining both techniques might beneficial to selected patients. The role of percutaneous management will likely expand since its role in improving patient's quality of life with very minimal procedure-related risk and in conjunction with future technological advancement.

Radiofrequency ablation of osteoid osteoma: Aiming for excellent outcomes in an Australasian context

INTRODUCTION

To report a series of patients with osteoid osteoma treated by radiofrequency ablation in whom no complications or recurrences occurred.

METHODS

Over a 13-year period, 32 consecutive patients with osteoid osteoma were treated by radiofrequency ablation in an Australasian teaching centre.

RESULTS

All patients had resolution of symptoms with no complication or recurrence.

CONCLUSIONS

This series is further evidence for the use of radiofrequency ablation as the primary treatment for osteoid osteoma.

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.

Efficacy of One-Stage Posterior Debridement and Bone Grafting with Internal Fixation in the Treatment of Monosegmental Thoracolumbar Tuberculosis

BACKGROUND

We explored the clinical effect of one-stage posterior debridement and bone grafting with internal fixation for the treatment of monosegmental thoracolumbar tuberculosis (TB).

METHODS

The data from 90 patients with thoracolumbar TB, who had undergone one-stage posterior debridement and bone grafting with internal fixation, were retrospectively reviewed. Data on the operative time, blood loss, length of hospital stay, erythrocyte sedimentation rate, C-reactive protein, improvement of neurological function, visual analog scale score, vertebral Cobb angle, bone healing, and complications were collected.

RESULTS

A total of 88 patients were finally included in the present retrospective study, included 42 men and 46 women. The mean patient age was 45.4 ± 12.3 years (range, 27-70), and the mean duration of disease until treatment was 11 ± 4.5 months (range, 3-19). The mean operative time was 167.0 minutes (range, 130-210), and the mean blood loss was 767.4 mL (range, 500-1150). At the final follow-up examination, the correction in the Cobb angle was 19°, the visual analog scale score had decreased to 3 ± 1.72, the neurologic deficits using the Frankel grade had improved, and the erythrocyte sedimentation rate and C-reactive protein level had returned to normal levels.

CONCLUSION

One-stage posterior debridement and bone grafting with internal fixation might be a better choice for treating patients with monosegment thoracolumbar TB.

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

Purpose

To investigate effects and heat distribution of radiofrequency ablation (RFA) on vertebral tumors in vitro and in vivo swine experiments and its clinical application.

Materials and methods

RFA was performed on the swine spine in vitro and in vivo for 20 min at 90 °C at the electrode tip, and the temperature at the electrode tip and surrounding tissues were recorded. Clinical application of ablation combined with vertebroplasty was subsequently performed in 4 patients with spinal tumors.

Results

In the in vitro study, the mean temperature at the front and ventral wall of the spinal canal was 50.8 °C and 43.6 °C, respectively, at 20 mm significantly greater than 37.7 °C and 33.7 ± 1.7 °C, respectively, at 10 mm ablation depth. The coagulative necrosis area was significantly (P < 0.0001) greater at 20 mm depth than at 10 mm depth (mean 17.0 × 20.7 mm² vs. 14.2 × 16.6 mm²). In the in vivo experiment, the local temperature increased significantly (P < 0.05) from around 36 °C before ablation to over 41 °C at 20 min after ablation, with the temperature at the electrode tip (90.4 °C) and within the vertebral body (67.0 °C) significantly (P < 0.05) greater than at the posterior (41.9 °C) and lateral wall (41.8 °C). From 2 to 5 weeks, bone remodeling began. Clinically, all four patients had successful RFA and vertebroplasty, with no neurological deficits. The pain scores were significanlty (P < 0.05) improved before (4.5–10, mean 8.0) compared with at four weeks (0–1.8, mean 1.8).

Conclusion

The clustered electrode can be efficiently and safely applied in the treatment of spinal tumors without damaging the spinal cord and adjacent nerves by heat distribution.

Percutaneous radiofrequency ablation in osteoid osteoma: Tips and tricks in special scenarios

OBJECTIVES

To define specific characteristics of osteoid osteomas treated with radiofrequency ablation, that may benefit from special technical recommendations.

METHODS

Retrospective analysis of all radiofrequency ablations performed by our group from January 2001 to March 2015. A descriptive study was conducted. We compared our results with the available literature to determine the most frequent special scenarios.

RESULTS

207 radiofrequency ablations were performed in 200 patients. We defined the following scenarios: osteoid osteomas located in the spine, close to neurovacular structures, osteoid osteomas in small bones (hands and feet), intra-articular, deeply located or superficial and lesions with extensive periosteal reaction.

CONCLUSIONS

The scenarios defined required special considerations and technical variations. Implementing the different tips and tricks shown in the article, the most complex osteoid osteomas could be successfully ablated.

Radiofrequency ablation of osteoid osteoma in the atlas: A case report

Osteoid osteoma of the atlas has previously been reported very rarely in the published literature. The traditional standard treatment has been a surgical resection of the nidus. Recently, computed tomography (CT)-guided radiofrequency ablation (RFA) has gained favor as a more precise alternative treatment. Here, we present a case of osteoid osteoma of the C1 lateral mass treated successfully using CT-guided RFA. A 30-year-old woman who presented with a four-month history of occipital and suboccipital pain was treated by CT-guided RFA. The visual analog scale (VAS) assessed the pain before and after RFA. The patient reported significant pain relief and normal activities. The VAS score reduced from 8/7 to 1/0 after the procedure. Therefore CT-guided percutaneous RFA of C1 vertebral osteoid osteoma is a safe and effective method. The technique might be contraindicated when the nidus is less than 2 mm away from the neural structures.

Epidural Balloon Placement for Protection of the Spinal Canal During Cryoablation of Paraspinal Lesions

Ablation of paraspinal lesions close to the spinal canal and neuroforamina requires protective measures in order to protect the spinal cord and nerve roots. Various methods of protection have been previously described including infusion of saline and CO₂. Regardless, neuromonitoring should be adjunctively performed when ablating spinal lesions close to neuronal structures. Balloon protection has been previously described during ablation of renal masses. The benefit of balloon protection in paraspinal mass ablation is it physically displaces the nerve roots as opposed to CO₂ or saline which has the potential to insulate but because of its aerosolized or fluid nature may or may not provide definitive continuous protection throughout an ablation. This report details three paraspinal lesions, two of which were successfully ablated with the use of a balloon placed in the epidural space to provide protection to the spinal cord and nerve roots.

Neurophysiological Monitoring in Radiofrequency Ablation of Spinal Osteoid Osteoma With a Progressive Time and Temperature Protocol in Children

STUDY DESIGN

Retrospective. Level IV Evidence.

OBJECTIVE

To assess the utility of intraoperative neurophysiological monitoring (IONM) to detect and eventually prevent impending neurovascular damage during computed tomography (CT)-guided radiofrequency ablation (RFA) of spinal osteoid osteoma (OO) in children.

SUMMARY AND BACKGROUND DATA

To our knowledge, this is the first case series of spinal OO in pediatric patients treated at a single center employing IONM during RFA.

METHODS

This is a retrospective study of seven consecutive patients (3 girls and 4 boys, mean age: 9 years 4 months) with imaging and clinical signs compatible with spinal OO who underwent CT-guided RFA, under general anesthesia, and IONM in a single center between 2011 and 2015. Before the RFA procedure, a CT-guided percutaneous biopsy of the nidus was performed in the same setting. RFA was divided into four cycles of increasing time and temperature and performed under IONM in every patient.

RESULTS

Two patients had lesions located in the thoracic spine and five patients had lumbar involvement. The RFA technical and clinical success was 85.7%. Six patients presented with reversible neurophysiological changes either during biopsy needle positioning or RFA cycles. In the remaining case, as IONM changes did not improve after several minutes of neuroprotective hypertension, the procedure was interrupted. Neither neurologic nor vascular complications were observed after RFA treatment. In only one biopsy sample, OO was confirmed by histopathologic studies.

CONCLUSION

CT-guided RFA is an accepted minimally invasive technique for the treatment of spinal OO in children. IONM may be a helpful tool that requires minimal additional time and provides feedback on the state of the spinal cord and nerves at risk during the procedure. We promote the use of IONM during these procedures to detect and possibly prevent impending neurologic damage.

LEVEL OF EVIDENCE

Level IV.

Spinal osteoid osteoma: efficacy and safety of radiofrequency ablation

OBJECTIVE

The aim of this study was to evaluate the efficacy and complications of CT-guided radiofrequency ablation (RFA) of spinal osteoid osteoma (OO).

MATERIALS AND METHODS

Between 2002 and 2012, a total of 61 patients (46 male and 15 female, mean age 26.4 ± 12.7 years) were subjected to RFA for spinal OO. The diagnosis of OO was made after a period of pain and symptoms of 20.6 ± 14.4 months. RFA was performed under conscious sedation and local analgesia. Clinical symptoms were evaluated at 3, 6, and12 months, and at the end of the time of the present investigation. Mean follow-up was 41.5 ± 7.1 months.

RESULTS

The primary efficacy of RFA, complete regression of symptoms, was obtained in 57 out of 61 patients (93.4%). Four out of 61 (6.5%) patients showed a relapse of OO (after 3 months); 2 out of 4 were subjected to a second RFA, the remaining ones were subjected to surgery. There was one complication (case of lower limb paresthesia for 30 days after the ablation) and one possible complication (a disc herniation).

CONCLUSION

CT-guided RFA is an excellent treatment for spinal OO. Our data suggest that this procedure should be considered for the first stage of therapy for this disease.