The use of microwaves ablation in the treatment of epiphyseal osteoid osteomas

The efficacy and safety of microwave ablation in managing osteoid osteoma: a systematic review

INTRODUCTION

Microwave ablation (MWA) utilizes electromagnetic methods to destroy tumors, employing devices operating at 900 MHz or above frequencies. MWA has emerged as a recent alternative for treating osteoid osteoma (OO), providing similar accessibility, safety, and technical effectiveness as radiofrequency ablation. This systematic review aims to evaluate the safety and efficacy of MWA in treating OO.

METHODS

A systematic review of published studies on the use of MWA in managing OO was conducted. Studies were excluded if they were 1) not written in English, 2) case reports, 3) lacked adequate peer review, or 4) consisted solely of abstracts. Before full-text assessment, titles, and abstracts were screened. Extracted data included author, year, study design, patient count, age, gender, OO site, ablation power (watts), duration, complications, outcome, and recurrence. The data were analyzed and presented as means, frequencies, and percentages.

RESULTS

Eight studies, including 143 cases, met the inclusion criteria; among these cases, 59.44% were male, and the mean age was 19.03 ± 7.09. Most of the OOs were in the femur, 54.54%. MWA at 60 W was the prevailing power setting, utilized in 37 cases (25.87%), with an ablation time of 90 s for 95 cases (66.43%). Clinical success was achieved in 137 (95.80%) cases, with recurrence observed in 4 cases (2.80%). However, 16 minor and major complications were observed despite the overall success.

CONCLUSION

Percutaneous MWA may represent an efficient choice for the minimally invasive management of OO, demonstrating a minimal risk of complications and recurrence.

Percutaneous CT-Guided Microwave Ablation for the Treatment of Osteoid Osteomas: A Single Center Experience

RATIONALE AND OBJECTIVES

The aim of the current study was to evaluate the feasibility and effectiveness of CT-guided microwave ablation (MWA) in the treatment of osteoid osteomas (OO).

MATERIALS AND METHODS

Data from 59 consecutive patients who underwent percutaneous CT-MWA for OO treatment were examined in the current retrospective study. The period of this study spanned from January 2021 to May 2023 at a single institution. The study involved an evaluation of clinical and radiological characteristics, procedural data, Visual Analog Scale (VAS) pain scores, complication incidences, as well as clinical and technical success rates. Statistical analyses were performed by using the Wilcoxon test with Bonferroni correction, Friedman, Spearman, Mann-Whitney U test.

RESULTS

59 patients with an average age of 17.31 ± 8.53 years underwent CT-guided MWA for the treatment of OO. The procedure demonstrated a high success rate, with 96.6% of cases achieving both technical and clinical success. However, recurrence was observed in two patients (3.4%) at the three-month follow-up. These cases were successfully managed with a second MWA procedure. The median VAS pain scores reported by the patients was significantly improved post-procedure: from 8.64 ± 1.14 before treatment to 0.63 ± 0.98 in the first month, 0.41 ± 1.02 in the third month, and 0.15 ± 0.45 in the sixth month. Only one patient (1.7%) experienced a minor complication; no major complications were recorded in this study.

CONCLUSION

CT-guided percutaneous MWA is a minimally invasive and a highly effective and safe approach for the treatment of OO.

Microwave in situ inactivation in the treatment of bone giant cell tumor: a mid-term descriptive study

AIM

To evaluate the mid-term clinical efficacy of microwave in situ inactivation combined with bone grafting or polymethyl methacrylate (PMMA) filling in the treatment of giant cell tumor of bone (GCTB).

METHODS

This is a retrospective, descriptive, and analytical study. A total of 30 GCTB patients received microwave in situ inactivation from January 2012 to January 2020, whose clinical recurrence rate was evaluated at the last follow-up after microwave in situ inactivation surgery. The Musculoskeletal Tumor Society (MSTS) function score was used to evaluate the postoperative clinical panoramic results.

RESULTS

All patients were followed up for 21 to 110 months, with an average of 63.79 months. Distal femur (40%) and proximal tibia (28%) had a higher rate of GCTB incidence. Seventeen percent of tumor patients suffered from associated pathologic fracture. The rate of Campanacci classification stage III was 60%. The average MSTS score was evaluated as 27.53 points overall at the last follow-up. In terms of complications, three, two, two and one cases developed fat liquefaction, controllable tissue rejection reaction, incision infection and degenerative changes around lesion joint, respectively, without in situ recurrences and reoperation as well as distant lung metastasis.

CONCLUSIONS

The method of microwave in situ inactivation combined with bone grafting or PMMA filling is prudently recommended as one of the options for the limb salvage treatment of giant cell tumor of long and periarticular bone.

LEVEL OF EVIDENCE

IV: case series.

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.

CT-guided microwave ablation of osteoid osteoma: Long-term outcome in 28 patients

PURPOSE

The purpose of this study was to assess the long-term efficacy of CT-guided microwave ablation (MWA) in the treatment of osteoid osteoma. Secondary objectives were to assess early outcome and side-effects of MWA.

MATERIALS AND METHODS

Twenty-eight consecutive patients (18 men, 10 women) with a median age of 19.5 years (IQR: 16, 25.5) with a total of 28 non-spinal osteoid osteoma treated by CT-guided MWA were retrospectively included. The ablations were performed with a median power and duration of 60 Watt and 1 min 30 s, respectively. Pain referred to osteoid osteoma was assessed at predefined time points using a 0-10 numeric rating scale. At one month, contrast-enhanced follow-up MRI was performed to evaluate the nidus vascularization and the volume of necrosis induced by MWA. Clinical success was defined by the absence of osteoid osteoma-related pain, and technical success was defined by the presence of necrosis of the nidus on the one-month post-MWA MRI.

RESULTS

Long term success rate was 93% (26/28) after a follow-up of 55.5 months (IQR: 25.75, 74.5) and technical success rate was 96 % (25/26). One late failure was observed after a patient had been declared cured at one month but the formal proof of a late recurrence of osteoid osteoma could not be brought. Three minor complications were reported including mild reversible superficial radial nerve injury with a skin burn (grade 2) in one patient and moderate skin burn only in two patients.

CONCLUSION

Our results suggest that CT-guided MWA is an effective option for a minimally-invasive treatment of osteoid osteoma with a low rate of complication and no late recurrence.

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.

Percutaneous computed tomography-guided radiofrequency ablation of a spinal osteoid osteoma abutting the dura: a case report and review of the literature

PURPOSE

Osteoid osteomas in the spine constitute a challenging group for both surgical and percutaneous approaches. Purpose of the present study is to report a case report of a spinal osteoid osteoma in a challenging spinal location and review literature for safety and efficacy of the technique.

METHODS

We report a case of spinal osteoid osteoma extending in the epidural space and abutting the dura in a pediatric patient treated by percutaneous computed tomography-guided radiofrequency ablation. This is not a systematic review of the literature. A number of separate literature searches were performed. Non-English studies and case reports were excluded from the study. All references of the obtained articles were also evaluated for any additional information.

RESULTS

Although all prophylactic measures were taken (hydrodissection, thermocouples and neurophysiologic monitoring) and the procedure was uneventful, patient within three hours, was unable to raise or bend the unilateral lower extremity below the knee. Pain reduction was significant from the first morning post-ablation and during the follow-up period of 18 months. MR scan was within normal limits. Dexamethasone was iv injected for 24 h and prescribed per os for 7 days. At follow-up 1 week later mobility of the lower extremity had returned to normal.

CONCLUSION

As far as spine ablation is concerned, all prophylactic measures should be taken; neurophysiologic monitoring seems to be more sensitive than temperature measurement. Intravenous and per os corticosteroids are extremely useful in case of nerve damage.

Osteoid Osteoma: An Updated Review of Epidemiology, Pathogenesis, Clinical Presentation, Radiological Features, and Treatment Option

Osteoid osteoma, the third most common benign bone tumor, usually occurs in the cortex of long bones. It consists of a radiolucent nidus surrounded by reactive osteosclerosis. Generally, osteoid osteoma affects young males. Nocturnal pain that eases with salicylates or nonsteroidal anti-inflammatory drugs (NSAID) is the typical clinical presentation. Sometimes, it remains undiagnosed for a long time. Plain radiography and computed tomography are usually sufficient for the diagnosis of osteoid osteoma. Initial treatment includes salicylates and NSAID because the tumor often regresses spontaneously over 2-6 years. Surgical treatment is indicated in case of unresponsive pain to medical therapy, no tolerance of prolonged NSAID therapy due to side effects, and no willingness to activity limitations. Nowadays, minimally invasive techniques have replaced open surgery and are considered the gold standard of surgical treatment. Although cryoablation seems superior in terms of the nerve damage and immunotherapy effect, radiofrequency ablation is the preferred technique.

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.

Radiofrequency ablation vs microwave ablation for osteoid osteomas: long-term results

OBJECTIVE

Osteoid osteomas are benign bone tumors commonly treated using thermal ablation. We compare the technical success, complication rates, and long-term efficacy of the two most common ablation types: radiofrequency and microwave.

MATERIALS AND METHODS

A retrospective study was performed of all osteoid osteoma ablation procedures between 2007 and 2017. A ten-point numerical pain scale was used to quantify symptoms before and after the procedures with > 12-month follow-up. Complications were reported using the Society of Interventional Radiology Adverse Events reporting criteria.

RESULTS

Twenty-nine patients successfully underwent 15 radiofrequency ablations and 15 microwave ablations with a technical success rate of 83% for radiofrequency and 100% for microwave (p = 0.23). Long-term recurrence rates (p = 1.0) and complication rates (p = 0.60) were not significantly different for the groups. One patient developed a skin burn following microwave ablation and another developed 12 months of sciatic neuropathy following radiofrequency ablation.

CONCLUSION

Microwave and radiofrequency ablation are safe and effective methods for treating osteoid osteomas with similar long-term efficacies. Although radiofrequency ablation is more commonly reported to result in skin burns, this complication can arise during microwave ablation.

Percutaneous thermal ablation for treatment of osteoid osteoma: a systematic review and analysis

OBJECTIVE

Although radiofrequency ablation is well validated for treatment of osteoid osteoma, newer technologies, namely cryoablation, have been less thoroughly studied. The purpose is to perform a systematic review and pooled analysis of percutaneous ablation technologies for treatment of osteoid osteoma with subset analysis of intra-articular and spinal tumors.

MATERIAL AND METHODS

A total of 36 of 79 identified manuscripts met inclusion criteria, comprising 1863 ablations in 1798 patients. Inclusion criteria were (1) retrospective or prospective analysis of thermal ablation of osteoid osteomas in any location, (2) at least 6 months of clinical follow-up, (3) 10 or more patients, (4) patients not included in a second study included in this review, and (5) English language or English translation available. Success rate was defined as all ablations minus technical failures, clinical failures, and recurrences. Subset analysis of intra-articular and spinal tumors was performed.

RESULTS

Overall success rate was 91.9% (95% CI 91-93%). Technical failure, clinical failure, and recurrence rates were 0.3%, 2.1%, and 5.6% respectively. Complications were seen in 2.5% (95% CI 1.9-3.3%) patients. There was no significant difference when comparing radiofrequency ablation and cryoablation (p = 0.92). Success rates for intra-articular (radiofrequency ablation) and spinal tumors (radiofrequency and cryoablation) were 97% and 91.6% respectively.

CONCLUSION

Percutaneous ablation of osteoid osteomas was highly successful with low complication rates. Efficacy of radiofrequency ablation and cryoablation is similar, which is consequential because cryoablation is associated with decreased pain, predictable nerve regeneration, and theoretical immunotherapy benefits. Treatment of more challenging intra-articular and spinal lesions demonstrated similarly high success and low complication rates.

Clinical Guideline for Microwave Ablation of Bone Tumors in Extremities

Microwave ablation has been used to treat bone tumors in extremities for more than 30 years. With improved recognition, updated microwave equipment, and expanded clinical application, microwave ablation has recently been widely used to treat bone tumors. To standardize the application of microwave ablation in the clinical treatment of bone tumors in the limbs, research results and clinical experience involving the use of microwave ablation to treat bone tumors in the limbs have been summarized, and a clinical guideline has been designed. This guideline is aimed at providing a reliable clinical basis for indications, preoperative evaluation and decision-making, perioperative treatment, complications, and other issues via evidence-based medicine. Two aspects are considered-percutaneous microwave ablation and intraoperative microwave ablation of bone tumors in extremities. Ultimately, the guideline is intended to standardize treatment and improve the clinical efficacy of microwave ablation of bone tumors in extremities.

Use of percutaneous microwave ablation for the treatment of bone tumors: a retrospective study of clinical outcomes in 47 patients

Objective

The present study aimed to evaluate the short-term clinical performance and safety of percutaneous microwave ablation (MWA) techniques for the treatment of bone tumors.

Methods

This single-institution retrospective study investigated 47 cases of bone tumors treated by MWA from June 2015 to June 2018. The study included 26 patients (55.3%) with benign bone tumors and 21 patients (44.7%) with malignant bone tumors. The tumors were located in the spine or sacrum (15, 31.9%), the upper extremities (6, 12.8%), the lower extremities (17, 36.2%) and the pelvis (9, 19.1%). Outcomes regarding clinical efficacy, including pain relief, quality of life, and intervention-related complications, were evaluated before and after MWA using the visual analog scale (VAS) and the 36-item Short-Form Health Survey (SF-36) scoring system.

Results

Of the 47 patients included in this study, all of them completed follow-up examinations, with a mean follow-up duration of 4.8 ± 1.6 months (range, 2–9 months). Significantly improved VAS and SF-36 scores were recorded after the initial treatment (P<0.001), suggesting that almost 100% of patients experienced pain relief and an improved quality of life following surgery. No major intervention-related complications (e.g., serious neurovascular injury or infection) occurred during or after the treatment. We recorded only three minor posttreatment complications (6.4%, 3/47), which were related to thermal injury that caused myofasciitis and affected wound healing.

Conclusion

In our study, the short-term efficacy of MWA was considerably favorable, with a relatively low rate of complications. Our results also showed that MWA was effective for pain relief and improved patients’ quality of life, making it a feasible treatment alternative for bone tumors.

Microwave ablation of osteoid osteoma: initial experience and efficacy

BACKGROUND

Image-guided percutaneous microwave ablation has been used to treat adult osteoid osteomas but has not been thoroughly evaluated in the pediatric population.

OBJECTIVE

To evaluate the technical feasibility and clinical efficacy of microwave ablation to treat osteoid osteomas in pediatric patients.

MATERIALS AND METHODS

The electronic medical record and imaging archive were reviewed for 24 consecutive patients who had undergone microwave ablation of osteoid osteomas between January 1, 2015, and May 31, 2018, at a single tertiary care pediatric hospital. All patients were diagnosed by clinical and imaging criteria, and referred by a pediatric orthopedic surgeon after failing conservative management with pain medication. The average age of the patients was 13.3 years (range: 3-18 years), and the average size of the osteoid osteoma nidus was 8.8 mm (range: 5-22 mm). Technical success was defined as placement of the microwave antenna at the distal margin of the lesion nidus and achievement of the target ablation temperature. Clinical findings were assessed pre- and post-ablation and clinical success was defined as complete relief of pain without pain medication at 1-month follow-up. The number and severity of complications were also documented.

RESULTS

Clinical success was achieved in 100% of patients (24/24), with all reporting complete cessation of pain medication use 1 week after treatment and 0/10 pain at 1 month. There were 4 minor complications (17%) including access site numbness and a minor soft-tissue infection. There were no major complications.

CONCLUSION

Microwave ablation is a technically feasible and clinically effective treatment for pediatric osteoid osteomas.

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.

3D printed personalized titanium plates improve clinical outcome in microwave ablation of bone tumors around the knee

Microwave ablation has been widely accepted in treating bone tumor. However, its procedure is time-consuming and usually results in postoperative fractures. To solve this problem, we designed and fabricated titanium plates customized to the patients’ bone structures. The personalized titanium plates were then used for fixation after the removal of tumorous tissue. Specifically, 3D models of tumor-bearing bone segments were constructed by using computed tomography (CT) and magnetic resonance imaging (MRI). The 3D models were used to design the personalized titanium plates. The plate model was transferred into a numerical control machine for manufacturing the personalized titanium plates by 3D printing. The plates were then surgically implanted for reconstruction assistance following microwave-induced hyperthermia to remove the bone tumor. Implementation parameters and knee functions were then evaluated. No postoperative fractures, implant failures or loosening problems occurred; mean Musculoskeletal Tumor Society score was 27.17 from the latest follow-up. Mean maximum flexion of affected knees was 114.08°. The results of knee gait analysis were comparable with normal population data. Our work suggests that personalized titanium plates can significantly improve the clinical outcomes in the surgical removal of bone tumor. This study represents the first-time effort in using personalized titanium plates for such surgery.

Prospective pilot study of CT-guided microwave ablation in the treatment of osteoid osteomas

PURPOSE

The aims of this work were to assess the feasibility and efficacy of CT-guided microwave ablation (MWA) in the treatment of osteoid osteomas (OOs).

MATERIALS AND METHODS

Thirteen consecutive patients (range 11-31 years old) presenting with OO were prospectively included and treated by CT-guided MWA. Power and duration of MWA were both recorded. The patient's pain was assessed using a numeric pain rating scale (NRS), and side effects were recorded during procedures, after 1 day, 7 days and 1 month. The nidus vascularization and the volume of necrosis induced by MWA were assessed using contrast-enhanced MRI. Success was defined as the complete relief of the patient's pain 1 month after the first procedure, associated with necrosis of the nidus on follow-up MRI.

RESULTS

The success rate was up to 92.3% (12/13). At 1 day, 7 days and 1 month, the median NRSs were respectively 5 [interquartile range (IQR) 2-5], 0 (IQR 0-1) and 0 (IQR 0-0). Side effects observed were one partial and self-resolving lesion of a sensory branch of the radial nerve and two skin burns. The median power of the MWA used was 60 W (IQR 50-60) with a 1.5-min duration (IQR 1-2), leading to MWA-induced necrosis measuring on average 23 × 15 × 16 mm.

CONCLUSION

CT-guided MWA of OO has a success rate that appears to be almost similar to that of laser or radiofrequency ablation, but care must be taken to prevent nerve or skin lesions.

Percutaneous Biopsy and Radiofrequency Ablation of Osteoid Osteoma with Excess Reactive New Bone Formation and Cortical Thickening Using a Battery-Powered Drill for Access: A Technical Note

PURPOSE

To report our experience with the use of a battery-powered drill in biopsy and radiofrequency ablation of osteoid osteoma with excess reactive new bone formation. The battery-powered drill enables obtaining the sample while drilling.

MATERIALS AND METHODS

During the last 18 months, 14 patients suffering from painful osteoid osteoma with excess reactive new bone formation underwent CT-guided biopsy and radiofrequency ablation. In order to assess and sample the nidus of the osteoid osteoma, a battery-powered drill was used. Biopsy was performed in all cases. Then, coaxially, a radiofrequency electrode was inserted and ablation was performed with osteoid osteoma protocol. Procedure time (i.e., drilling including local anesthesia), amount of scans, technical and clinical success, and the results of biopsy are reported.

RESULTS

Access to the nidus through the excess reactive new bone formation was feasible in all cases. Median procedure time was 50.5 min. Histologic verification of osteoid osteoma was performed in all cases. Radiofrequency electrode was coaxially inserted within the nidus and ablation was successfully performed in all lesions. Median amount CT scans, performed to control correct positioning of the drill and precise electrode placement within the nidus was 11. There were no complications or material failure reported in our study.

CONCLUSIONS

The use of battery-powered drill facilitates access to the osteoid osteoma nidus in cases where excess reactive new bone formation is present. Biopsy needle can be used for channel creation during the access offering at the same time the possibility to extract bone samples.

Paediatric musculoskeletal interventional radiology

Interventional radiology technique is now well established and widely used in the adult population. Through minimally invasive procedures, it increasingly replaces surgical interventions that involve higher percentages of invasiveness and, consequently, of morbidity and mortality. For these advantageous reasons, interventional radiology in recent years has spread to the paediatric age as well. The aim of this study was to review the literature on the development, use and perspectives of these procedures in the paediatric musculoskeletal field. Several topics are covered: osteomuscle neoplastic malignant and benign pathologies treated with invasive diagnostic and/or therapeutic procedures such as radiofrequency ablation in the osteoid osteoma; invasive and non-invasive procedures in vascular malformations; treatment of aneurysmal bone cysts; and role of interventional radiology in paediatric inflammatory and rheumatic inflammations. The positive results that have been generated with interventional radiology procedures in the paediatric field highly encourage both the development of new ad hoc materials, obviously adapted to young patients, as well as the improvement of such techniques, in consideration of the fact that childrens' pathologies do not always correspond to those of adults. In conclusion, as these interventional procedures have proven to be less invasive, with lower morbidity and mortality rates as well, they are becoming a viable and valid alternative to surgery in the paediatric population.

Percutaneous bone lesion ablation

Benign tumors and metastatic bone lesions can be treated by ablation techniques performed either alone or in combination with other percutaneous techniques. Ablation techniques include ethanol or acetic acid injection and thermal ablation by means of energy deposition [including laser, radiofrequency, microwave, cryoablation, radiofrequency ionization and magnetic resonance (MR)-guided high-intensity focused ultrasound (HIFU)]. Goal definition of the therapy is crucial: ablation techniques can be proposed as curative treatments in benign bone tumors or oligometastatic disease (<3 lesions). Alternatively, these techniques can be proposed as palliative treatments aiming at reduction of pain, local control of the disease and tumor decompression. Depending on the lesion's location ablation can be combined with cementation with or without further metallic augmentation; local tumor control can be enhanced by combining ablation with transarterial bland embolization or chemoembolization. Thermal ablation of bone and soft tissues is characterized by high success and relatively low rates of potential complications, mainly iatrogenic thermal damage of surrounding sensitive structures. Successful thermal ablation requires a sufficient ablation volume and thermal protection of the surrounding vulnerable structures. This article will describe the general principles governing ablation and the mechanism of action for each technique and in addition will review the literature about safety and effectiveness of percutaneous imaging-guided ablation for benign and malignant (primary and metastatic) lesions.

Percutaneous image-guided ablation of bone and soft tissue tumours: a review of available techniques and protective measures

Background

Primary or metastatic osseous and soft tissue lesions can be treated by ablation techniques.

Methods

These techniques are classified into chemical ablation (including ethanol or acetic acid injection) and thermal ablation (including laser, radiofrequency, microwave, cryoablation, radiofrequency ionisation and MR-guided HIFU). Ablation can be performed either alone or in combination with surgical or other percutaneous techniques.

Results

In most cases, ablation provides curative treatment for benign lesions and malignant lesions up to 3 cm. Furthermore, it can be a palliative treatment providing pain reduction and local control of the disease, diminishing the tumour burden and mass effect on organs. Ablation may result in bone weakening; therefore, whenever stabilisation is undermined, bone augmentation should follow ablation depending on the lesion size and location.

Conclusion

Thermal ablation of bone and soft tissues demonstrates high success and relatively low complication rates. However, the most common complication is the iatrogenic thermal damage of surrounding sensitive structures. Nervous structures are very sensitive to extremely high and low temperatures with resultant transient or permanent neurological damage. Thermal damage can cause normal bone osteonecrosis in the lesion’s periphery, surrounding muscular atrophy and scarring, and skin burns. Successful thermal ablation requires a sufficient ablation volume and thermal protection of the surrounding vulnerable structures.

Teaching points

• Percutaneous ablations constitute a safe and efficacious therapy for treatment of osteoid osteoma.

• Ablation techniques can treat painful malignant MSK lesions and provide local tumour control.

• Thermal ablation of bone and soft tissues demonstrates high success and low complication rates.

• Nerves, cartilage and skin are sensitive to extremely high and low temperatures.

• Successful thermal ablation occasionally requires thermal protection of the surrounding structures.