Radiofrequency ablation versus magnetic resonance guided focused ultrasound surgery for minimally invasive treatment of osteoid osteoma: a propensity score matching study

US-Guided Interventional Procedures for Total Hip Arthroplasty

In patients with total hip arthroplasty (THA) with recurrent pain, symptoms may be caused by several conditions involving not just the joint, but also the surrounding soft tissues including tendons, muscles, bursae, and peripheral nerves. US and US-guided interventional procedures are important tools in the diagnostic work-up of patients with painful THA given that it is possible to reach a prompt diagnosis both directly identifying the pathological changes of periprosthetic structures and indirectly evaluating the response and pain relief to local injection of anesthetics under US monitoring. Then, US guidance can be used for the aspiration of fluid from the joint or periarticular collections, or alternatively to follow the biopsy needle to collect samples for culture analysis in the suspicion of prosthetic joint infection. Furthermore, US-guided percutaneous interventions may be used to treat several conditions with well-established minimally invasive procedures that involve injections of corticosteroid, local anesthetics, and platelet-rich plasma or other autologous products. In this review, we will discuss the clinical and technical applications of US-guided percutaneous interventional procedures in painful THA that can be used in routine daily practice for diagnostic and therapeutic purposes.

Osteoid osteoma of the distal radius presenting as an inconspicuous swelling in a young child

Osteoid osteoma is a benign osteoblastic tumour with a predilection for the lower extremity that rarely affects the forearm. It is commonly seen in adolescents and young adults, and is seldom diagnosed in the paediatric age group. We report a boy in his early childhood who presented with a swelling over the distal forearm, which was incidentally noted by the mother 3 months ago. Plain radiographs showed diffuse sclerosis of the dorsal cortex of the distal radius. CT scan showed a central lucent nidus in the intramedullary region and surrounding sclerosis in the radial metaphysis, confirming the diagnosis of osteoid osteoma. The patient was successfully treated by surgical en bloc resection of the nidus and was asymptomatic at 1-year follow-up. Non-specific symptoms at presentation make it a challenge to diagnose osteoid osteoma in children and it needs to be considered in the differential diagnosis when radiographs show lytic lesions in the bone.

High-intensity focused ultrasound-a needleless management for osteoid osteoma: a systematic review

Osteoid osteoma is one of the most frequent benign musculoskeletal neoplasm. Radiofrequency ablation is the method of choice for non-conservative treatment of osteoid osteoma. Recently, high-intensity focused ultrasound (HIFU) has been proposed as a safer option. The objective of this study is to review the efficacy and side effects of HIFU in the management of osteoid osteoma. A comprehensive search was conducted in PubMed, Science Direct, and Clinical Key until June 30, 2022. Demographic data, baseline characteristics, success rates, pre- and post-procedure pain scores, recurrences, and complications were recorded. Eleven studies were included in this systematic review. Pooled analysis that involved 186 subjects resulted in an overall success rate of 91.94%. Recurrence was reported in two studies, in which it occurred in 4/177 (2.26%) subjects. Skin burn was found in 1 (0.54%) patients. No major or other complications were reported. Three studies compared the success rate of HIFU and RFA. Success rate was slightly higher in the RFA group with insignificant difference (p = 0.15). High-intensity focused ultrasound showed promising results. It offers a safer treatment approach for osteoid osteoma, especially in children, and can be considered for recalcitrant cases after RFA. Nonetheless, more studies are expected in the future.

Update on musculoskeletal applications of magnetic resonance-guided focused ultrasound

Magnetic resonance-guided focused ultrasound (MRgFUS) is a noninvasive, incisionless, radiation-free technology used to ablate tissue deep within the body. This technique has gained increased popularity following FDA approval for treatment of pain related to bone metastases and limited approval for treatment of osteoid osteoma. MRgFUS delivers superior visualization of soft tissue targets in unlimited imaging planes and precision in targeting and delivery of thermal dose which is all provided during real-time monitoring using MR thermometry. This paper provides an overview of the common musculoskeletal applications of MRgFUS along with updates on clinical outcomes and discussion of future applications.

Efficacy and safety of magnetic resonance-guided focused ultrasound for the treatment of osteoid osteoma: A systematic review and meta-analysis

OBJECTIVE

Magnetic resonance-guided focused ultrasound (MRgFUS) is a novel noninvasive interventional technique for osteoid osteoma (OO). The purpose of this study was to evaluate the efficacy and safety of MRgFUS in the treatment of OO through a systematic review and meta-analysis of pain scores and post-treatment adverse events before and after MRgFUS treatment.

MATERIALS AND METHODS

A comprehensive literature search of PubMed, Embase, Web of science, and Cochrane Library databases was conducted to screen the study literature based on inclusion and exclusion criteria to extract and analyze pre- and post-treatment pain score data, success rates (complete pain relief with no recurrence until the last follow-up), recurrence rates, secondary intervention rates, and complications to evaluate the efficacy and/or safety of MRgFUS for OO.

RESULTS

A total of 113 studies published between 2012 and 2022were collected, resulting in a total sample size of 353 patients. The majority of the studies were prospective and had a follow-up period of 4 weeks or more, and overall, the quality of evidence ranged from low to high. Pain scores at 1 week and 1 month after the merger were 0.62 (9.5% CI:0.28-0.96) and 0.37 (9.5% CI:0.07-0.68), respectively. The success rate of the combination was 92.8% (95% CI: 89.8%-95.7%), the incidence of minor complications (thermal injury at the ablation site) was 0.85%, and no major complications were recorded in any of the included literature.

CONCLUSION

MRgFUS is an effective procedure that is able to treat pain for patients with OO with satisfying efficacy and safety.

PROSPERO

No.CRD42023415573.

Intra-articular Osteoid Osteoma of the Intermediate Cuneiform Bone Causing Articular Degeneration: A Rare Case and Literature Review

Osteoid osteoma of the cuneiform bone is an exceedingly rare and easily missed cause of foot pain. The uncharacteristic and nonspecific radiographs of such intra-articular osteoid osteoma further increase difficulty in making the diagnosis. To date, there has been no description of intra-articular osteoid osteoma of the intermediate cuneiform bone causing articular degeneration in any published literatures. We present a case of intra-articular osteoid osteoma of the intermediate cuneiform bone causing articular degeneration, who underwent curettage, allograft bone graft, and navicular-cuneiform arthrodesis. The patient presented with radiographic bone union, full motor function recovery and pain-free at the 22-month follow-up. This report adds to the existing literature. Intra-articular osteoid osteoma of the intermediate cuneiform bone causing articular degeneration is an exceedingly rare and easily missed cause of foot pain. It proves a complicated and challenging task to identify intra-articular osteoid osteoma. Clinicians should be particularly careful not to exclude the possibility of arthritis and, thus, vigilant when choosing the surgical option.

A CT-free protocol to treat osteoid osteoma of the hip region in childhood and adolescence by percutaneous drilling and by hip arthroscopy

INTRODUCTION

It is often difficult to clinically and radiologically diagnose intra-articular osteoid osteomas and osteoid osteomas of the hip joint. Treatment can also be difficult due to complex locational relationships. CT-guided radiofrequency ablation is currently the standard form of treatment.In this paper we report on a minimally-invasive concept for treating osteoid osteomas near the hip joint in children and adolescents which does not involve using computed tomography.

MATERIAL AND METHOD

10 patients with an average age of 12.1 years underwent treatment for osteoid osteomas in the hip joint region. The diagnosis was made using a contrast-enhanced MRI. The osteoid osteomas were marked percutaneously using x-ray and MRI guidance. MRI-guided drilling/curettage was performed in 4 cases and arthroscopic resection in 6 cases.

RESULTS

All lesions were successfully treated using the MRI-guided method. All patients were free of pain after the treatment. There was no instance of recurrence during the follow-up period, which averaged 10 months. The effective dose for marking the lesion was between 0.0186 mSv and 0.342 mSV (mean 0.084 mSV).

CONCLUSIONS

Our MRI diagnostics protocol, the MRI-guided drilling and the minimally invasive hip arthroscopy represent an alternative to CT-guided radiofrequency ablation in the treatment of osteoid osteomas. Radiation exposure can thereby be significantly reduced. Hip arthroscopy can also be used to treat secondary pathologies such as femoroacetabular impingement.

The surgical management of osteoid osteoma: A systematic review

Background

Osteoid osteoma (OO) comprises approximately 11%-14% of benign bone tumors. The main symptom of OO is localized pain accompanied by nighttime aggravation. Surgical treatment is frequently used in clinic, including open surgery and percutaneous ablation, the latter including radiofrequency ablation, cryoablation, and microwave ablation, but there is no consensus on when and how to choose the best treatment for OO.

Purpose

We did a systematic review of the literature on existing surgical treatments of OO to assess the safety and efficacy of surgical treatments of OO and to evaluate the surgical options for different locations of OO.

Methods

The inclusion criteria in the literature are 1. Patients diagnosed with osteoid osteoma and treated surgically; 2. Include at least five patients; 3. Perioperative visual analogue scale (VAS), postoperative complications, and recurrence were recorded; 4. Literature available in PubMed from January 2014 to December 2021.

Results

In the cohort, 1565 patients (mainly adolescents) with OO received 1615 treatments. And there are 70 patients with postoperative recurrence and 93 patients with postoperative complications (minor: major=84:9). The results of Kruskal-Wallis examination of each experimental index in this experiment were clinical success rate H=14.818, p=0.002, postoperative short-term VAS score H=212.858, p<0.001, postoperative long-term VAS score H=122.290, p<0.001, complication rate H=102.799, p<0.001, recurrence rate H=17.655, p<0.001, the technical success rate was H=45.708, p<0.001, according to the test criteria of α=0.05, H₀ was rejected. The overall means of the outcome index in each group were not completely equal.

Conclusion

Percutaneous ablation and open surgery are safe and reliable for OOs, and the technical success rate of percutaneous ablation is higher than that of open surgery. Open surgery and cryoablation can be selected for OOs close to the nerve and atypical sites, while radiofrequency ablation and microwave ablation can be selected for OOs in most other sites.

A new versatile MR-guided high-intensity focused ultrasound (HIFU) device for the treatment of musculoskeletal tumors

Magnetic Resonance (MR) Imaging-guided High Intensity focused Ultrasound (MRgHIFU) is a non-invasive, non-ionizing thermal ablation therapy that is particularly interesting for the palliative or curative treatment of musculoskeletal tumors. We introduce a new modular MRgHIFU device that allows the ultrasound transducer to be positioned precisely and interactively over the body part to be treated. A flexible, MR-compatible supporting structure allows free positioning of the transducer under MRI/optical fusion imaging guidance. The same structure can be rigidified using pneumatic depression, holding the transducer rigidly in place. Targeting accuracy was first evaluated in vitro. The average targeting error of the complete process was found to be equal to 5.4 ± 2.2 mm in terms of focus position, and 4.7° ± 2° in terms of transducer orientation. First-in-man feasibility is demonstrated on a patient suffering from important, uncontrolled pain from a bone metastasis located in the forearm. The 81 × 47 × 34 mm³ lesion was successfully treated using five successive positions of the transducer, under real-time monitoring by MR Thermometry. Significant pain palliation was observed 3 days after the intervention. The system described and characterized in this study is a particularly interesting modular, low-cost MRgHIFU device for musculoskeletal tumor therapy.

Post-Procedural Follow-Up of the Interventional Radiology’s Management of Osteoid Osteomas and Osteoblastomas

The family of painful osteocytic tumors includes osteoblastomas and osteoid osteomas—these lesions are considered benign, but they could produce a significant painful symptomatology. Usually, people affected are between 20 s and 30 s. When symptomatic, an effective treatment is mandatory for the management of these lesions to allow for a ful quality of life. The possibilities of treatment range from chirurgical en-block resection (procedure of surgical oncology aiming to remove a tumoral mass in its entirety, completely surrounded by a continuous layer of healthy tissue) to interventional approaches that, nowadays, are considered the most affordable and sustainable in terms of effectiveness, recovery after procedure, and for bone structure sparing. The main techniques used for osteoid osteomas and osteoblastomas are radio frequency ablation (RFA) and magnetic resonance-guided focused ultrasound (MRgFUS): the most important difference between these approaches is the needleless approach of MRgFUS, which further reduces the minimal invasiveness of RFA (and the related consequences) and the absence of exposure to ionizing radiation. Despite their high efficacy, a recurrence of pathology may occur due to a failure in therapy. In light of this, describing the various possibilities of follow up protocols and the imaging aspects of recurrence or incomplete treatment is mandatory. In the scenario given in the literature, many authors have tried to asses an organized follow up protocol of these patients, but many of them did not undergo periodical magnetic resonance (MR) or computerized tomography (CT) because of the lack of symptomatology. However, even if it seems that clinical evolution is central, different papers describe the protocol useful to detect eventual relapse. The aim of our manuscript is to review the various possibilities of follow-up of these patients and to bring together the most salient aspects found during the management of these osteocytic bone lesions.

Computed tomography guided radiofrequency ablation of osteoid osteoma in children: a single center's experience

OBJECTIVE

To report a single center's experience evaluating the efficacy and safety of computed tomography-guided radiofrequency ablation for the treatment of osteoid osteoma in children.

MATERIALS AND METHODS

Institutional database research identified 33 symptomatic patients (≤ 18 years of age; male/female ratio: 21/12, mean age 13.09 ± 3.66) with osteoid osteoma who were treated by CT-guided RFA. Technical and clinical success as well as complication rates were recorded. The duration of the procedure, the number of computed tomography scans and the results of the biopsy were assessed. Pain, prior, the following morning and 1 week, 1/6/12 months after the procedure were compared by means of a numeric visual scale (NVS) questionnaire.

RESULTS

Mean lesion size was 8.28 ± 4.24 mm. Mean follow-up was 23.33 ± 17.61 months (range 12-62). Mean pain score prior to radiofrequency ablation was 9.06 ± 0.80 NVS units. On week 1 and 1/6/12 months, all patients were pain-free reporting 0 NVS units (p < 0.05). The mean procedure time was 54 min (range 51-59) and a mean of 7 CT scans were performed during the ablation session. RF electrode was successfully placed in the center of the nidus in all cases. In our study, none of our patient experienced recurrence of the pain, nor complications.

CONCLUSION

The present study demonstrates that percutaneous CT-guided radiofrequency ablation constitutes a safe and effective technique for osteoid osteoma treatment in children.

Interventional Radiology’s Osteoid Osteoma Management: Percutaneous Thermal Ablation

Osteoid osteoma (OO) is one of the most common benign bone tumors with specific clinical and radiological characteristics. Analgesic therapy and surgical treatment have been considered the only therapy for a long time. Recently, safe and effective new therapeutic options have been introduced, among which percutaneous thermal ablation techniques. This review aims to describe the recent updates in the field of percutaneous thermal ablation techniques in the treatment of OO, assessing the outcomes in terms of efficacy, complications, and recurrence rate.

Weakening or Structural Strengthening? An Evaluation of Bone Density after MRgFUS Ablation for Treatment of Benign Bone Lesions

Previous studies suggest that interventional ablative procedures on bone lesions may weaken the bone, especially when performed through the needle approach. Our purpose was to evaluate, through Computed Tomography (CT), the effects of Magnetic Resonance guided Focused Ultrasound Surgery (MRgFUS) ablation on painful osteoid osteomas and osteoblastomas in terms of bone density and morphological changes. We retrospectively evaluated patients treated at our institution with MRgFUS for superficial, painful osteoid osteoma or osteoblastoma during the last 9 years. Inclusion criteria were procedural and clinical success, as well as the availability of pre- and postprocedural CT examinations. Imaging features assessed were perilesional/nidus density changes and the occurrence of pathological fractures during the follow-up period. Our study population included 31 osteoid osteomas and 5 intra-articular osteoblastomas in 36 treated patients. We found an increased bone density of the lesions when pre and post-treatment CT- values were compared: these differences were statistically significant, and this finding is consistent with significant bone densification at the post-treatment imaging follow-up. No pathological fractures were observed after ablation during the follow-up. MRgFUS can be considered to be the treatment of choice for benign superficial bone lesions, thanks to its minimal invasiveness, excellent effectiveness, and safety. Pathological fractures, reported in literature as a rare event using needle ablation, never occurred in our MRgFUS treatment series.

Needleless Ablation of Osteoid Osteoma and Osteoblastoma: The Emergent Role of MRgFUS

Osteoblastoma (OB) and osteoid osteoma (OO) are benign bone-forming tumors, with nearly identical basic microscopic features. The main difference is dimension (OO has usually a nidus measuring <2 cm in diameter). In addition, OB is biologically more active than OO, with a tendency to grow in size. Historically, treatments have included surgical resection and analgesics, although invasiveness and poor tolerance have led to the current standard of care moving toward interventional radiology, where radiofrequency ablation (RFA) represents the most diffuse technique. Magnetic resonance-guided focused ultrasound surgery (MRgFUS) has recently emerged as another innovative alternative treatment, providing tumor ablation through a needleless and ionizing radiation-free modality. In addition, this technique has the ability to guarantee a very precise and controlled increase in temperature, delivering small amounts of energy that can accurately destroy only the lesion, avoiding healthy surrounding tissues. The present review focuses on MRgFUS as the less invasive, safe, effective, and durable treatment option for the management of osteoid osteoma and osteoblastoma, including a description of technical details, indications and outcomes.

Musculoskeletal Applications of Magnetic Resonance-Guided Focused Ultrasound

Magnetic resonance-guided focused ultrasound (MRgFUS) is a novel noninvasive therapy that uses focused sound energy to thermally ablate focal pathology within the body. In the United States, MRgFUS is approved by the Food and Drug Administration for the treatment of uterine fibroids, palliation of painful bone metastases, and thalamotomy for the treatment of essential tremor. However, it has also demonstrated utility for the treatment of a wide range of additional musculoskeletal (MSK) conditions that currently are treated as off-label indications. Advantages of the technology include the lack of ionizing radiation, the completely noninvasive technique, and the precise targeting that offer unprecedented control of the delivery of the thermal dose, as well as real-time monitoring capability with MR thermometry. In this review, we describe the most common MSK applications of MRgFUS: palliation of bone metastases, treatment of osteoid osteomas, desmoid tumors, facet arthropathy, and other developing indications.

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.

Osteoblastoma: When the Treatment Is Not Minimally Invasive, an Overview

Background: osteoblastoma is a bone-forming tumor accounting for about 1% of all primary bone tumors and 3% of benign bone tumors. The gold-standard treatment is surgical excision; nevertheless, minimally invasive radiological techniques such as thermoablation and, more recently, high intensity focused ultrasound are gaining more importance. The aim of the present paper is to analyze surgical indications based on our experience and on the evidences in the literature. Methods: all patients affected by osteoblastoma who underwent surgical excision in January 2009 and December 2018 were reviewed; eleven patients were enrolled in the study. The epidemiological aspects, size of the disease and site of onset, symptoms, surgery type, indications, and results are reported for every case. Results: all treatments were based on a preoperative diagnosis; pain was constant in all cases. Intralesional surgeries were performed in 9 out of 11 cases; the remaining 2 cases underwent wide resection. No early or late complications occurred after the surgical procedure. The indications for surgery were lesions very close to nerves or joints, unclear diagnosis, risk of fracture, lesion too large for radiofrequency thermoablation, or failure of minimally invasive treatments. At a medium follow-up of 88 months, no local recurrences were verified. Conclusions: osteoblastoma is a rare tumor with difficult diagnosis. Identification is based on symptoms, imaging, and histology. When possible, minimally invasive techniques is preferred for treatment but surgery is still considered the gold standard.

A Bicentric Propensity Score Matched Study Comparing Percutaneous Computed Tomography-Guided Radiofrequency Ablation to Magnetic Resonance-Guided Focused Ultrasound for the Treatment of Osteoid Osteoma

PURPOSE

To assess the safety and efficacy of computed tomography-guided radiofrequency (RF) ablation and magnetic resonance-guided focused ultrasound (MRgFUS) in the treatment of osteoid osteoma with a long-term follow-up study.

MATERIALS AND METHODS

Database research was performed at 2 different centers with experience in musculoskeletal interventions. Both centers, one performing RF ablation and the other MRgFUS, identified 116 patients who underwent either RF ablation or MRgFUS procedures for the treatment of symptomatic osteoid osteoma and retrospectively evaluated data regarding pain scores using a visual analog scale (VAS). Complications were recorded according to the Cardiovascular and Interventional Radiological Society of Europe classification system. Propensity score matching for multiple variables was performed. Pain scores before and after therapy were compared.

RESULTS

Of 116 patients treated, 61 and 55 underwent RF ablation and MRgFUS, respectively. Before treatment, the mean reported pain in the 2 groups were 9.1 ± 0.88 (RF ablation) and 8.7 ± 0.73 (MRgFUS) VAS units. After treatment, a statistically significant (P < .00001) overall reduction in pain symptomatology was recorded. No statistically significant difference was observed between the mean values of pain after treatment in both groups (P = .256). Over a mean of >2 years of follow-up, 4 cases of relapse (RF ablation, 1; MRgFUS, 3) and 1 complication (RF ablation) were observed. The analysis from propensity score matching that identified a matched cohort of 48 patients showed similar results.

CONCLUSIONS

The 2 techniques for the treatment of osteoid osteoma resulted in profound and similar pain relief. The presence of thick cortical bone over the nidus can reduce the effectiveness of MRgFUS.

Focused Ultrasound (FUS) for Chronic Pain Management: Approved and Potential Applications

Chronic pain is one of the leading causes of disability and disease burden worldwide, accounting for a prevalence between 6.9% and 10% in the general population. Pharmacotherapy alone results ineffective in about 70-60% of patients in terms of a satisfactory degree of pain relief. Focused ultrasound is a promising tool for chronic pain management, being approved for thalamotomy in chronic neuropathic pain and for bone metastases-related pain treatment. FUS is a noninvasive technique for neuromodulation and for tissue ablation that can be applied to several tissues. Transcranial FUS (tFUS) can lead to opposite biological effects, depending on stimulation parameters: from reversible neural activity facilitation or suppression (low-intensity, low-frequency ultrasound, LILFUS) to irreversible tissue ablation (high-intensity focused ultrasounds, HIFU). HIFU is approved for thalamotomy in neuropathic pain at the central nervous system level and for the treatment of facet joint osteoarthritis at the peripheral level. Potential applications include HIFU at the spinal cord level for selected cases of refractory chronic neuropathic pain, knee osteoarthritis, sacroiliac joint disease, intervertebral disc nucleolysis, phantom limb, and ablation of peripheral nerves. FUS at nonablative dosage, LILFUS, has potential reversible and tissue-selective effects. FUS applications at nonablative doses currently are at a research stage. The main potential applications include targeted drug and gene delivery through the Blood-Brain Barrier, assessment of pain thresholds and study of pain, and reversible peripheral nerve conduction block. The aim of the present review is to describe the approved and potential applications of the focused ultrasound technology in the field of chronic pain management.

Technique Success, Technique Efficacy and Complications of HIFU Ablation for Palliation of Pain in Patients With Bone Lesions: A Meta-Analysis of 28 Feasibility Studies

Several feasibility studies have reported that high-intensity focused ultrasound (HIFU) ablation can be applied to ease patients' bone pain. However, the effect of HIFU ablation to palliate bone pain remains unclear. To evaluate the technique's success, efficacy, minor complication and major complication on patients suffering from bone pain, we searched the PubMed, MEDLINE, EMBASE and Cochrane Library databases from January 1998 to March 2019. Clinical studies that have assessed the association between bone pain and HIFU ablation were involved. We filtered out 28 feasibility studies, which reported the association between HIFU ablation and bone pain, including a total of 717 patients and 736 bone lesions. Overall, our results indicate that the rate of technique success of HIFU ablation was 93% (95% confidence interval [CI] 89%-96%) for patients with bone lesions. The technique efficacy rate of HIFU ablation for palliation of pain from bone lesions was 80% (95% CI 74%-87%) in all the patients, 96% (91%-100%) in the subgroup of retrospective studies and 77% (69%-85%) in the subgroup of prospective studies. In regard to HIFU ablation treatment safety, the hazard ratio for minor complication was 12% (95% CI 7%-17%), and the hazard ratio for major complication was 2% (95% CI 1%-3%). In conclusion, the summary rates for various considerations of using HIFU ablation for the palliation of bone pain are as follows: technique success is 93%, technique efficacy is 77%, minor complication is 12% and major complication is 2%. Our results suggest that extracorporeal HIFU ablation is a promising method for palliation of pain in bone lesions, with high technique success and efficacy, but low adverse events.

Osteoid osteoma: which is the best mininvasive treatment option?

Osteoid osteoma is the third most common benign bone tumor, with well-known clinical presentation and radiological features. Although surgical excision has been the only therapeutic option for a long time, to date it has been replaced by minimally invasive techniques, which proved satisfactory success rates and low complication occurrence. Therefore, the purpose of this literature review was to describe the main updates of these recent procedures in the field of interventional radiology, with particular attention paid to the results of the leading studies relating to the efficacy, complications, and recurrence rate. Nevertheless, this study aimed to analyze the peculiarities of each reported technique, with specific focus on the possible improvements and pitfalls. Results proved that all mininvasive procedures boast a high success rate with slight number of complications and a low recurrence rate. Radiofrequency ablation is still considered the gold standard procedure for percutaneous treatment of osteoid osteoma, and it has the possibility to combine treatment with a biopsy. Interstitial laser ablation's advantages are the simplicity of use and a lower cost of the electrodes, while cryoablation allows real-time visualization of the ablated zone, increasing the treatment safety. Magnetic resonance-guided focused ultrasound surgery is the most innovative non-invasive procedure, with the unquestionable advantage to be radiation free.

Synergistic Effects of Pulsed Focused Ultrasound and a Doxorubicin-Loaded Microparticle-Microbubble Complex in a Pancreatic Cancer Xenograft Mouse Model

The synergistic effects of a doxorubicin (Dox)-loaded microparticle-microbubble complex (DMMC) and focused ultrasound (FUS) with a short duty cycle (5%) were evaluated in a pancreatic cancer xenograft model established by inoculating immunodeficient mice with CFPAC-1 cells. The efficacy of the DMMC with FUS (study 1), the effect of conjugating the particles as opposed to mixing them (study 2) and the levels of tumor apoptosis and intracellular Dox (study 3) were evaluated. The DMMC with FUS exhibited the lowest tumor growth rate (30.8 mm³/wk) and the highest intracellular Dox uptake (8.8%) and tumor cell apoptosis rate (58.7%) among all treatments. DMMC had a significantly lower growth rate than the mixture of Dox-loaded microparticles and microbubbles (44.2 mm³/wk, p < 0.01) when they were combined with FUS. In conclusion, DMMC with short-duty-cycle FUS holds promise for tumor growth suppression, which may be attributed to high intracellular Dox uptake.

French Multidisciplinary Approach for the Treatment of MSK Tumors

Several interventional treatments have recently been integrated into the therapeutic armamentarium available for the treatment of bone tumors. In some scenarios (e.g., osteoid osteoma), interventional treatments represent the sole and definitive applied treatment. Due to the absence of widely shared protocols and the complex multivariate scenarios underlying the clinical presentation of the remaining bone tumors including metastases, therapeutic strategies derived from a multidisciplinary tumor board are essential to provide effective treatments tailored to each patient. In the present review, we present the multidisciplinary therapeutic strategies commonly adopted for the most frequent bone tumors.

CT-guided radiofrequency ablation for osteoid osteomas: a systematic review

OBJECTIVES

CT-guided radiofrequency ablation (CT-RFA) is considered to be the gold standard for treatment of osteoid osteoma (OO) yet treatment failures (TFs) continue to be reported. This systematic review was conducted to evaluate factors associated with TF, such as ablation time, lesion location, and patient age as well as evaluating how TF has trended over time.

METHODS

Original studies reporting on patients undergoing CT-RFA of OO published between 2002 and 2019 were identified. TF was defined as patients with (1) recurrent or persistent pain +/- (2) imaging evidence of persistent OO. TFs were subdivided into those occurring after the index procedure (primary TF) or those occurring after repeat RFA (secondary TF). Subgroup analysis was performed for TF based on the study date (2002-2010 or 2010-2019), time duration of ablation at 90 °C (6 min or > 6 min), patient age, and tumor location (spinal vs. appendicular).

RESULTS

Sixty-nine studies were included for a total of 3023 patients. The global primary TF rate was 8.3% whereas the secondary TF rate was 3.1%. The TF rate reported in studies published after 2011(7%) was about half that during the earlier time period 2002-2010 (14%). There was no statistical difference in TF corrected for age, OO location, or duration of ablation (respectively p = 0.39, 0.13, and 0.23). The global complication rate was 3%, the most frequent being skin burns (n = 24; 0.7%).

CONCLUSIONS

A decrease in TF observed between 2011-2019 compared to 2002-2010 may reflect improvements in operator technique or advancements in equipment. Duration of ablation, patient age, or location of OO failed to significantly correlate with TF.

KEY POINTS

• CT-guided radiofrequency ablation of osteoid osteomas is a safe technique with a low rate of treatment failure (8.3% failure rate after the primary radiofrequency reducing to 3.1% following a secondary treatment). • The treatment failure rate has decreased over time, possibly due to an improved understanding of the disease process, better technique, and advances in equipment. • Duration of ablation, patient age, or lesion location did not significantly correlate with treatment failure.

An experience-based review of HIFU in functional interventional neuroradiology: transcranial MRgFUS thalamotomy for treatment of tremor

Tremor is a common and very disabling symptom in patients with essential tremor and Parkinson's disease. In the recent years, transcranial ablation of thalamic nuclei using magnetic resonance guided high-intensity focused ultrasound has emerged as a minimally invasive treatment for tremor. The aim of this review is to discuss, in the light of our single-center experience, the technique, current applications, results, and future perspectives of this novel technology.

Evolution of the imaging features of osteoid osteoma treated with RFA or MRgFUS during a long-term follow-up: a pictorial review with clinical correlations

Interventional radiology is today considered the first-line treatment for osteoid osteoma both in the form of needle-guided technique of ablation (Radiofrequency) and of needleless technique (magnetic resonance-guided focused ultrasound surgery). The follow-up study of the procedures is mainly clinical, since the disappearance of pain is consistent with the success of the procedure. However, due to the minimally invasive and innovative nature of the approach, interpretation of the follow-up imaging could be ambiguous and misleading. Aim of our review was to define the main findings on the imaging that can best describe the regular evolution of these types of treatment. In particular, four findings were considered: (1) bone marrow oedema; (2) reactive phenomena (perilesional inflammatory reaction for extra-articular lesions or synovial reaction for intra-articular lesions); (3) bone remodelling (disappearance of the nidus and bone healing); (4) ring sign (considered as the granulation tissue around the nidus treated). These findings were evaluated using MRI and CT with a follow-up study that lasted up to 24 months.

Emerging hyperthermia applications for pediatric oncology

Local application of hyperthermia has a myriad of effects on the tumor microenvironment as well as the host's immune system. Ablative hyperthermia (typically > 55 °C) has been used both as monotherapy and adjuvant therapy, while mild hyperthermia treatment (39-45 °C) demonstrated efficacy as an adjuvant therapy through enhancement of both chemotherapy and radiation therapy. Clinical integration of hyperthermia has especially great potential in pediatric oncology, where current chemotherapy regimens have reached maximum tolerability and the young age of patients implies significant risks of late effects related to therapy. Furthermore, activation of both local and systemic immune response by hyperthermia suggests that hyperthermia treatments could be used to enhance the anticancer effects of immunotherapy. This review summarizes the state of current applications of hyperthermia in pediatric oncology and discusses the use of hyperthermia in the context of other available treatments and promising pre-clinical research.

Thermal Therapy With a Fully Electronically Steerable HIFU Phased Array Using Ultrasound Guidance and Local Harmonic Motion Monitoring

The method of localized harmonic motion (LHM) monitoring has been proposed as an ultrasound-based monitoring technique for in vivo real-time ultrasound-guidance during thermal surgery.

OBJECTIVE

The focus of this paper is to study the performance of LHM monitoring in vivo in order to assess the tissue coagulation during ultrasound surgery of bone metastases. This is done through a pre-clinical study on large scale animals (pigs) as well as a first-in-human pilot study, using a hand held ultrasound-guided HIFU phased array.

METHODS

A flat, fully steerable HIFU phased array system (1024 elements, 100 mm diameter, 516 kHz), in combination with a co-aligned 64 element imaging system, is used to perform thermal surgery and monitor tissue coagulation using the LHM technique. The in vivo experiments are conducted using thirteen animals, followed by a first-in-human pilot study in which nine patients are enrolled.

RESULTS

The pre-clinical results show that the LHM monitoring method is able to detect about 80% of the observed coagulated tissue volumes visible in dissection. In the pilot study, six out of nine patients have durable pain reduction with good correlation observed from LHM detections.

CONCLUSION

In general, the results suggest that the LHM monitoring performance is promising in detecting thermal tissue coagulation during focused ultrasound surgery in tissues close to the bone.

SIGNIFICANCE

The LHM technique can offer a very accessible and cost-efficient monitoring solution during ultrasound surgery within a clinical setting.

Magnetic-resonance-guided focused ultrasound treatment of non-spinal osteoid osteoma in children: multicentre experience

BACKGROUND

Osteoid osteoma is a benign and painful musculoskeletal tumour that usually affects children. Current standard treatment is CT-guided radiofrequency ablation, a minimally invasive percutaneous procedure, with clinical success rates ranging between 85% and 98%. Though minimally invasive, however, this type of procedure is not free from complications.

OBJECTIVE

To investigate the efficacy and safety of magnetic resonance (MR)-guided focused ultrasound (MRgFUS), a needleless procedure of thermal ablation employed in the treatment of non-spinal osteoid osteoma in paediatric patients.

MATERIALS AND METHODS

We report the results of 33 procedures of ablation of osteoid osteoma performed with MRgFUS in three university hospitals. To ablate a lesion on the bone surface, MRgFUS employs the ultrasound energy transduced along the soft tissue. The follow-up studies lasted 24 months and were performed combining clinical and imaging data.

RESULTS

Mean age of the children was 13.8 years. The clinical outcome showed a primary success of 97%. One case alone was submitted to repeat treatment because the first one failed (secondary success). No major or minor complications were recorded. During the investigation time, no relapse of symptomatology or delayed complications were observed.

CONCLUSION

Although our study is preliminary and limited by a low number of patients, our data show that MRgFUS is effective. This suggests that it might be useful as the first-line treatment in paediatric patients with osteoid osteoma.

MR Imaging of the Upper Limb: Pitfalls, Tricks, and Tips

MR imaging is the modality of choice to evaluate musculoskeletal pathologies of the upper limb in most settings. However, due to the complexity in anatomy, MR imaging can give a false pathologic appearance and lead to several errors in the interpretation of MR imaging findings. Also, several artifacts can be confused with pathologic entities. This article reviews the most frequently encountered conditions in shoulder, elbow, and wrist MR imaging that can represent diagnostic pitfalls mimicking true pathology, together with some possible tips and tricks that can be useful to solve these equivocal cases and achieve a correct diagnosis.

Ultrasound-guided percutaneous irrigation of calcific tendinopathy: technical developments

Rotator cuff calcific tendinopathy (RCCT) is a common and painful shoulder disease characterised by deposition of calcium into the rotator cuff’s tendond. Different therapeutic options have been proposed, but the ultrasound-guided percutaneous irrigation (US-PICT) is been proved as an effective and safe first-line treatment. It can be performed with a single- of a double-needle tecnique, using warm saline solution to improve the dissolution of the calcific deposit. The procedure is ended with an intrabursal injection of local anaesthetics and slow-release steroids to improve the pain relief and to prevent complications. US-PICT leads to significative improvement in the shoulder funtion and pain relief in the short and long term, with a low complications rate. (www.actabiomedica.it)

Imaging of long head biceps tendon. A multimodality pictorial essay

The aim of this is article is to provide an  imaging review of normal anatomy, most common anatomical variants and pathologies of the long head of the biceps tendon (LHB) encountered during the daily practice.

Neuroimaging in emergency: a review of possible role of pineal gland disease

The pineal gland can be involved in a variety of neoplastic and congenital masses and tumors. Pineal gland neoplasms occur more frequently in children, accounting for 3-8% of intracranial tumors in the pediatric population. Pineal cysts are small lesions usually asymptomatic and encountered incidentally. Pathologic processes involving the pineal region produce signs and symptoms related to the mass effect on the adjacent structures and invasion of surrounding structures. These include several acute symptoms, such as increased intracranial pressure syndrome from obstruction of the aqueduct and consequent hydrocephalus, and Parinaud syndrome. Pineal apoplexy is rare and refers to the sudden neurological deterioration following hemorrhage in the pineal gland, most commonly into a pineal cyst. Knowledge of the clinical presentation and imaging features of these lesions is essential to narrow the differential diagnosis, especially when presenting with acute onset.

An MRI-guided HIFU-triggered wax-coated capsule for supertargeted drug release: a proof-of-concept study

BACKGROUND

Externally controlling and monitoring drug release at a desired time and location is currently lacking in the gastrointestinal tract. The aim of the study was to develop a thermoresponsive wax-coated capsule and to trigger its release upon applying a magnetic resonance imaging (MRI)-guided high-intensity focused ultrasound (HIFU) pulse.

METHODS

Capsules containing a lyophilised gadolinium-based contrast agent (GBCA) were coated with a 1:1 (mass/mass) mixture of lanolin and cetyl alcohol (melting point ≈43 °C) and exposed to simulated gastric and intestinal fluids (United States Pharmacopoeia) at 37 °C for 2 and 24 h, respectively. In a HIFU gel phantom, wax-coated capsules (n = 3) were tracked based on their T1- and T2-hypointensity by 1.5-T T1- and T2-weighted MRI pre- and post-exposure to an MRI-guided HIFU pulse.

RESULTS

Lanolin/cetyl alcohol-coated capsules showed high resistance to simulated gastrointestinal fluids. In a gel phantom, an MRI-guided HIFU pulse punctured the wax coating, resulting in the hydration and release of the encapsulated lyophilised GBCA and yielding a T1-hyperintense signal close to the wax-coated capsule.

CONCLUSION

We provide the proof-of-concept of applying a non-invasive MRI-guided HIFU pulse to actively induce the disintegration of the wax-coated capsule, and a method to monitor the release of the cargo via T1-weighted MRI based on the hydration of an encapsulated lyophilised GBCA. The wax-coated capsule platform enables temporally and spatially supertargeted drug release via the oral route and promises to address a currently unmet clinical need for personalised local therapy in gastrointestinal diseases such as inflammatory bowel diseases and cancer.

HIFU for Bone Metastases and other Musculoskeletal Applications

High-intensity focused ultrasound (HIFU) is a totally noninvasive procedure that has shown promising results in the management of numerous malignant and nonmalignant conditions. Under magnetic resonance or ultrasound guidance, high-intensity ultrasound waves are focused on a small, well-defined target region, inducing biologic tissue heating and coagulative necrosis, thus resulting in a precise and localized ablation. This treatment has shown both great safety and efficacy profiles, and may offer a multimodal approach to different diseases, providing pain palliation, potential local tumor control, and, in some cases, remineralization of trabecular bone. In musculoskeletal field, HIFU received FDA approval for treating bone metastasis, but its application has also been extended to other conditions, such as osteoid osteoma, desmoid tumor, low-flow vascular malformation, and facet joint osteoarthritis. This article illustrates the basic principles of HIFU and its main effects on biologic tissues with particular attention on bone, provides a step-by-step description of the HIFU procedure, and discusses the commonly treated conditions, in particular bone metastases.

Osteoid osteoma: Contemporary management

Osteoid osteoma is a benign bone-forming tumor with hallmark of tumor cells directly forming mature bone. Osteoid osteoma accounts for around 5% of all bone tumors and 11% of benign bone tumors with a male predilection. It occurs predominantly in long bones of the appendicular skeleton. According to Musculoskeletal Tumor Society staging system for benign tumors, osteoid osteoma is a stage-2 lesion. It is classified based on location as cortical, cancellous, or subperiosteal. Nocturnal pain is the most common symptom that usually responds to salicyclates and non-steroidal anti-inflammatory medications. CT is the modality of choice not only for diagnosis but also for specifying location of the lesion, i.e. cortical vs sub periosteal or medullary. Non-operative treatment can be considered as an option since the natural history of osteoid osteoma is that of spontaneous healing. Surgical treatment is an option for patients with severe pain and those not responding to NSAIDs. Available surgical procedures include radiofrequency (RF) ablation, CT-guided percutaneous excision and en bloc resection.

Present role and future perspectives of interventional radiology in the treatment of painful bone lesions

Interventional radiology has experienced an exponential growth in the last years. Nowadays it is possible to treat painful benign lesions or metastases with optimal results in terms of pain management and disease control. Among the benign lesions, osteoid osteoma is the most frequently treated with minimal invasive techniques and the results are excellent. Another lesion, traditionally treated with surgery (osteoblastoma) represent today another field of application. In the oncological field, metastases are, numerically, the most diffuse indications for treatment. Research carried out during the last decades has provided the interventional radiologist with a great variety of techniques of ablation and devices for monitoring the sensitive structures close to the target lesion. New ablation techniques and monitoring devices contribute to the achievement of significantly increasing rates of effectiveness and safety of interventional radiology procedures.

Role of interventional radiology in the management of musculoskeletal soft-tissue lesions

The lesions of the soft tissues are rare and extremely heterogeneous; even if the surgical treatment is usually the standard therapy, the role of the interventional radiology (IR) in this field is growing up for multiple reasons. First, because the imaging alone usually is not able to ensure a definitive diagnosis, IR has a basic role in the staging: the percutaneous biopsy is infact an irreplaceable step. Moreover, biopsy is necessary not only for histologic evaluations but also for the biochemical and molecular studies. Furthermore, the proved safety and effectiveness of IR in a multiple oncologial applications prompt a wider use also in this field.

Interventional radiology of the thyroid gland: critical review and state of the art

Thyroid nodules are a common incidental finding during a routinely ultrasound (US) exam unrelated to the thyroid gland in the healthy adult population with a prevalence of 20-76%. As treated before with surgery, in the last years new minimally invasive techniques have been developed as an alternative to surgery. The aim of this review, based on newly revised guidelines, is to provide some information regarding the basic principles, indications, materials, techniques, and results of mini-invasive procedures or treatments for thyroid nodules. We performed a narrative review including both newest and representative papers and guidelines based on the different procedures of ablation techniques developed in the last years for the diagnosis and the treatment of thyroid nodules. All examined papers referred very good results in term of volume nodule reduction, improvement in related symptoms and cosmetic problems, with a very low rate of complications and side effects for all the minimally invasive technique analyzed. Obviously, some differents between technique based on different kind of thyroid nodules and different indication were found. In conclusion, many thyroid nodules nowadays could be treated thanks to the advent of new mini-invasive technique that are less expensive and present a lower risk of major complications and side effects compared to surgery.

Weight-bearing MRI of the knee: a review of advantages and limits

Standard knee imaging with MRI is usually performed with patient in recumbent position under non-weight-bearing conditions. Recently, magnetic resonance imaging systems to scan the knee joint under weight bearing conditions has been proposed as an approach to improve the clinical utility of musculoskeletal MRI. Imaging under loading can be useful to understand the natural motion behavior of the knee joint and to identify conditions that are challenging to diagnose by using standard position. We reviewed the literature on weight-bearing MR imaging of the knee to describe the current state of use of such MRI technologies, evaluating the advantages and the potential limitations of these technologies.

Radiofrequency ablation of osteoid osteoma

Osteoid osteoma is a benign bone neoplasm with a reported incidence of 2-3% among all bone primary tumors. Although it is a small and benign lesion, it is often cause of patient complaint and discomfort. It is generally characterized by a long lasting, unremitting pain that typically exacerbates at night, often leading to sleep deprivation and functional limitation of the skeletal segment involved, with a significant reduction of patient daily life activities and consequent worsening of the overall quality of life. Over decades, complete surgical resection has represented the only curative treatment for symptomatic patients. In the last years, new percutaneous ablation techniques, especially radiofrequency ablation, have been reported to be a safe and effective alternative to classical surgery, with a low complication and recurrence rate, and a significant reduction in hospitalization cost and duration. The aim of this article is to provide an overview about the radiofrequency thermal ablation procedure in the treatment of osteoid osteoma. (www.actabiomedica.it)

Developments in the management of bone metastases with interventional radiology

Interventional radiology has known an exponential growth in the last years. Technological advances of the last decades, have made it possible to use new treatments on a larger scale, with safe and effective results. They could be considered as palliative treatments for painful lesions but also curative procedures, as single treatment or specially in combination with other techniques (surgery, radiation and oncology therapies, etc.).The main diffuse techniques are those of thermal ablation that destroy the target lesion through the heat; however there are also endovascular therapies that destroy the target tissue thanks to devascularization. Finally the is also the possibility to stabilize pathological fractures or impending fractures. In this paper all the most diffuse and effective techniques are reviewed and also a discussion of the main indications is done, with an analisys of the success and complications rates.

Magnetic Resonance Imaging correlates of benign and malignant alterations of the spinal bone marrow

BACKGROUND AND AIM OF THE WORK

Bone marrow (BM) abnormalities in the spine are a common, sometimes unexpected, finding on Magnetic Resonance Imaging (MRI), which is the most sensitive imaging modality to evaluate the marrow, and their interpretation can be difficult for the unexperienced radiologist. In this review, the MRI appearance of normal age-related BM changes, as well as the imaging features of benign and malignant diseases, are presented.

DISCUSSION

A large variety of BM signal alterations has been identified and described, including normal variants, BM reconversion,  degenerative changes, infections, spondyloarthritis and osteonecrosis, trauma, neoplastic lesions (both primary or metastatic), post-radiation and chemotherapy sequelae.

CONCLUSIONS

Knowledge of normal age-related BM appearance, normal variants and patterns of involvement in focal and diffuse bone diseases is essential, together with clinical and laboratory data, to narrow the list of the possible differential diagnoses. The radiologist should be familiar with these signal changes, as they can sometimes be discovered incidentally. In this context, it is equally important not to attribute pathological significance to benign alterations and to promptly detect signs of malignant diseases.

Interventional therapeutic procedures in the musculoskeletal system: an Italian Survey by the Italian College of Musculoskeletal Radiology

PURPOSE

To perform an online survey among all members of the Italian College of Musculoskeletal Radiology to understand how therapeutic musculoskeletal procedures are performed in daily practice in Italy.

METHODS

We administered an online survey to all 2405 members about the use of therapeutic musculoskeletal procedures in their institutions asking 16 different questions. Subgroup analysis was performed between general and orthopaedic hospitals with Mann-Whitney U and χ ² statistics.

RESULTS

A total of 129/2405 answers (5.4% of members) were included in our analysis. A median of 142.5 (25th-75th percentiles: 50-535.5; range 10-5000) therapeutic musculoskeletal procedures per single institution was performed in 2016. Arthropathic pain was the main indication. The most common procedures were joint injection, bursal/tendon injection, and irrigation of calcific tendinopathy. Ultrasound-guided procedures were mainly performed in ultrasonography rooms (77.4%) rather than in dedicated interventional rooms (22.6%). Conversely, fluoroscopic procedures were performed almost with the same frequency in interventional radiology suites (52.4%) and in general radiology rooms (47.6%). In most institutions (72%), autologous blood or components were not used. The median number of therapeutic musculoskeletal procedures performed in orthopaedic hospitals was significantly higher than in general hospitals (P = 0.002), as well as for the use of autologous preparations (P = 0.004).

CONCLUSION

Joint injection, bursal/tendon injection, and irrigation of calcific tendinopathy were the most common therapeutic musculoskeletal procedures, being arthropathic pain the main indication. The percentage of procedures and the use of autologous preparations were significantly higher in orthopaedic hospitals than in general hospitals.

Comparison of Noninvasive High-Intensity Focused Ultrasound with Radiofrequency Ablation of Osteoid Osteoma

OBJECTIVE

To evaluate clinical feasibility and safety of magnetic resonance imaging-guided high-intensity focused ultrasound (MR-HIFU) treatment of symptomatic osteoid osteoma and to compare clinical response with standard of care treatment.

STUDY DESIGN

Nine subjects with radiologically confirmed, symptomatic osteoid osteoma were treated with MR-HIFU in an institutional review board-approved clinical trial. Treatment feasibility and safety were assessed. Clinical response was evaluated in terms of analgesic requirement, visual analog scale pain score, and sleep quality. Anesthesia, procedure, and recovery times were recorded. This MR-HIFU group was compared with a historical control group of 9 consecutive patients treated with radiofrequency ablation.

RESULTS

Nine subjects (7 male, 2 female; 16 ± 6 years) were treated with MR-HIFU without technical difficulties or any serious adverse events. There was significant decrease in their median pain scores 4 weeks within treatment (6 vs 0, P < .01). Total pain resolution and cessation of analgesics were achieved in 8 of 9 patients after 4 weeks. In the radiofrequency ablation group, 9 patients (8 male, 1 female; 10 ± 6 years) were treated in routine clinical practice. All 9 demonstrated complete pain resolution and cessation of medications by 4 weeks with a significant decrease in median pain scores (9 vs 0, P < .001). One developed a second-degree skin burn, but there were no other adverse events. Procedure times and treatment charges were comparable between the 2 groups.

CONCLUSION

This pilot study shows that MR-HIFU treatment of osteoid osteoma refractory to medical therapy is feasible and can be performed safely in pediatric patients. Clinical response is comparable with standard of care treatment but without any incisions or exposure to ionizing radiation.

TRIAL REGISTRATION

ClinicalTrials.govNCT02349971.