CT-guided radiofrequency ablation of osteoid osteoma and osteoblastoma: Clinical success and long-term follow up in 77 patients

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

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

Spinal osteoid osteoma in the pediatric population: A management algorithm and systematic review

Purpose

The purpose of this study is to develop an accessible step-wise management algorithm for the management of pediatric spinal osteoid osteomas (OOs) based on a systematic review of the published literature regarding the diagnostic evaluation, treatment, and outcomes following surgical resection.

Methods

A systematic review of the literature was conducted on PubMed to locate English language studies reporting on the management of pediatric spinal OOs. Data extraction of clinical presentation, management strategies and imaging, and treatment outcomes were performed.

Results

Ten studies reporting on 85 patients under the age of 18 years presenting with OOs were identified. Back pain was the most common presenting symptom, and scoliosis was described in 8 out of 10 studies, and radicular pain in 7 out of 10 studies. Diagnostic, intraoperative, and postoperative assessment included radiographs, computed tomography (CT) scans, magnetic resonance imaging (MRI), bone scans, and frozen section. Treatment options varied, including conservative management, open surgical resection with or without intraoperative imaging, and percutaneous image-guided treatment. All included studies described partial or complete resolution of pain in the immediate postoperative period.

Conclusions

The proposed algorithm provides a suggested framework for management of pediatric spinal OOs based on the available evidence (levels of evidence: 3, 4). This review of the literature indicated that a step-wise approach should be utilized in the management of pediatric spinal OOs.

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

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

Interventional Imaging Techniques as Alternative to Surgery of the Foot and Ankle

A variety of foot and ankle pathologies can impair patient's daily activities, ultimately requiring surgical management. However, with improvements in image-guided intervention, the joints, soft tissues, and osseous structures may be accessible using various percutaneous techniques as a potential alternative therapeutic tool, avoiding the need for surgery with its associated risks and morbidity. This article discusses the potential range of image-guided interventional treatments. Injections, aspiration, biopsies, cryoablation, and radiofrequency ablation are described. Newer novel treatments are also covered. Finally, the common pathologies of Morton's neuroma, Achilles tendinopathy, and plantar fasciitis are addressed.

Tumors of the Spine: When Can Biopsy Be Avoided?

Regarding osseous tumors of the spine, characteristic morphology is encountered in hemangioma of the vertebral body, osteoid osteoma (OO), osteochondroma, Paget's disease, and bone islands. In these cases, radiologic imaging can make a specific diagnosis and thereby avoid biopsy, especially when the radiologist has chosen the correct imaging modality to establish the diagnosis, such as thin-slice computed tomography in suspected OO. A benign lesion is suggested by a high amount of fat within the lesion, the lack of uptake of the contrast agent, and a homogeneous aspect without solid parts in a cystic tumor. Suspicion of malignancy should be raised in spinal lesions with a heterogeneous disordered matrix, distinct signal decrease in T1-weighted magnetic resonance imaging, blurred border, perilesional edema, cortex erosion, and a large soft tissue component. Biopsy is mandatory in presumed malignancy, such as any Lodwick grade II or III osteolytic lesion in the vertebral column. The radiologist plays a crucial role in determining the clinical pathway by choosing the imaging approach wisely, by narrowing the differential diagnosis list, and, when characteristic morphology is encountered, by avoiding unnecessary biopsies.

Surgical treatment scenario for osteoblastoma of the pelvis: Long-term follow-up results

BACKGROUND

The aim of this study was to evaluate the results of different treatments for pelvic Osteoblastoma (OB).

METHODS

We retrospectively evaluated 34 patients affected by primary pelvic OB from 3 oncologic referral centers. Patients with a minimum follow-up of 24 months were included. Local recurrence (LR) rate and complications were recorded.

RESULTS

The primary treatment was radio-frequency ablation (RFA) in 4 patients (11.8%), curettage (ILC) in 21 (61.7%) and resection (EBR) in 9 (26.5%). Mean follow-up was 8.9 years (SD ± 6.6). Local recurrence free survival (LRFS) rate after primary surgery was 79.4% at 3 and 5 years. In details, LRFS rate at 3 and 5 years was 50.0% in RFA, 81.0% in ILC and 88.9% in EBR. Post-operative complications occurred in 6/34 patients (17.7%), in particular after EBR.

CONCLUSIONS

RFA is the least invasive technique to treat OB but with high LR rate. Thus, it should be reserved to very small lesions. ILC is a suitable treatment for stage II OB. For stage III OB, EBR is the treatment of choice, despite an increased risk of complications. For selected stage III OB (relatively small, periacetabular area) ILC might be considered.

Image-Guided Percutaneous Ablation for Primary and Metastatic Tumors

Image-guided percutaneous ablation methods have been further developed during the recent two decades and have transformed the minimally invasive and precision features of treatment options targeting primary and metastatic tumors. They work by percutaneously introducing applicators to precisely destroy a tumor and offer much lower risks than conventional methods. There are usually shorter recovery periods, less bleeding, and more preservation of organ parenchyma, expanding the treatment options of patients with cancer who may not be eligible for resection. Image-guided ablation techniques are currently utilized for the treatment of primary and metastatic tumors in various organs including the liver, pancreas, kidneys, thyroid and parathyroid, prostate, lung, bone, and soft tissue. This article provides a brief review of the various imaging modalities and available ablation techniques and discusses their applications and associated complications in various organs.

Computer 3D modeling of radiofrequency ablation of atypical cartilaginous tumours in long bones using finite element methods and real patient anatomy

BACKGROUND

Radiofrequency ablation (RFA) is a minimally invasive technique used for the treatment of neoplasms, with a growing interest in the treatment of bone tumours. However, the lack of data concerning the size of the resulting ablation zones in RFA of bone tumours makes prospective planning challenging, needed for safe and effective treatment.

METHODS

Using retrospective computed tomography and magnetic resonance imaging data from patients treated with RFA of atypical cartilaginous tumours (ACTs), the bone, tumours, and final position of the RFA electrode were segmented from the medical images and used in finite element models to simulate RFA. Tissue parameters were optimised, and boundary conditions were defined to mimic the clinical scenario. The resulting ablation diameters from postoperative images were then measured and compared to the ones from the simulations, and the error between them was calculated.

RESULTS

Seven cases had all the information required to create the finite element models. The resulting median error (in all three directions) was -1 mm, with interquartile ranges from -3 to 3 mm. The three-dimensional models showed that the thermal damage concentrates close to the cortical wall in the first minutes and then becomes more evenly distributed.

CONCLUSIONS

Computer simulations can predict the ablation diameters with acceptable accuracy and may thus be utilised for patient planning. This could allow interventional radiologists to accurately define the time, electrode length, and position required to treat ACTs with RFA and make adjustments as needed to guarantee total tumour destruction while sparing as much healthy tissue as possible.

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.

Cone beam computed tomography (CBCT) guidance is helpful in reducing dose exposure to pediatric patients undergoing radiofrequency ablation of osteoid osteoma

Purpose

To assess efficacy and safety of cone beam computed tomography (CBCT) in the radiofrequency ablation (RFA) of osteoid osteoma (OO) in children and adolescents, and to compare technical success, clinical success, radiation dose and procedure duration time of CBCT guidance to conventional computed tomography (CT) guidance.

Materials and methods

Between 2015 and 2019, 53 consecutive percutaneous RFA were performed on pediatric patients with CBCT or conventional CT guidance, respectively, in 24 and 29 children and adolescents with 24-month follow-up. Dose area product (DAP) and dose length product (DLP) were recorded, respectively, for CBCT and conventional CT and converted to effective doses (ED).

Results

CBCT and conventional CT groups were similar in terms of patient age and weight, tumor size and tumor location. Technical success was achieved in all cases. Primary clinical success was 91.67% (22/24) for the CBCT group and 89.66% (26/29) for the conventional CT group. Mean DAP was 64.75Gycm2 (range 6.0–266.7). Mean DLP was 972.62mGycm (range 337–2344). ED was significantly lower in the CBCT group compared to the conventional CT group (0.34 mSv vs. 5.53 mSv, p = 0.0119). Procedure duration time was not significantly longer in the CBCT group (102.25 min vs. 92.34 min, p = 0.065). No major complication was registered. Minor complications were observed in 4 patients (2 in CBCT; 2 in conventional CT).

Conclusions

Compared to conventional CT guidance, CBCT guidance for percutaneous OO ablation shows similar technical and clinical success rates, with reduced radiation dose and equivalent procedure duration time. This technique helps sparing dose exposure to pediatric patients.

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.

Effects of control temperature, ablation time, and background tissue in radiofrequency ablation of osteoid osteoma: A computer modeling study

To study the effects of the control temperature, ablation time, and the background tissue surrounding the tumor on the size of the ablation zone on radiofrequency ablation (RFA) of osteoid osteoma (OO). Finite element models of non-cooled temperature-controlled RFA of typical OOs were developed to determine the resulting ablation radius at control temperatures of 70, 80, and 90°C. Three different geometries were used, mimicking common cases of OO. The ablation radius was obtained by using the Arrhenius equation to determine cell viability. Ablation radii were larger for higher temperatures and also increased with time. All geometries and control temperatures tested had ablation radii larger than the tumor. The ablation radius developed rapidly in the first few minutes for all geometries and control temperatures tested, developing slowly towards the end of the ablation. Resistive heating and the temperature distribution showed differences depending on background tissue properties, resulting in differences in the ablation radius on each geometry. The ablation radius has a clear dependency not only on the properties of the tumor but also on the background tissue. Lower background tissue's electrical conductivity and blood perfusion rates seem to result in larger ablation zones. The differences observed between the different geometries suggest the need for patient-specific planning, as the anatomical variations could cause significantly different outcomes where models like the one here presented could help to guarantee safe and successful tumor ablations.

Percutaneous cryoablation of chondroblastoma and osteoblastoma in pediatric patients

BACKGROUND

To review the safety and efficacy of percutaneous cryoablation for the treatment of chondroblastoma and osteoblastoma in the pediatric and adolescent population.

MATERIALS AND METHODS

A retrospective review from 2016 to 2020 was performed to evaluate clinical and imaging response to percutaneous cryoablation in 11 symptomatic patients with diagnosis of chondroblastoma and osteoblastoma treated from two pediatric hospitals with at least 12-month follow-up. Technical success (correct needle placement and potential full coverage of the tumor with the planned ablation zone) and clinical success (relief of the symptoms) were evaluated. The primary objective was to alleviate pain related to the lesion(s). Immediate and late complications were recorded. Patients were followed in clinic and with imaging studies such as MRI or CT for a minimum of 6 months.

RESULTS

A total of 11 patients were included (mean 14 years, age range 9-17; male n = 8). Diagnoses were osteoblastoma (n = 4) and chondroblastoma (n = 7). Locations were proximal humerus (n = 1), femur condyle (n = 1), and proximal femur (n = 1) tibia (n = 3), acetabulum (n = 3), thoracic vertebra (n = 1) and lumbar vertebra (n = 1). Cryoablation was technically successful in all patients. Clinical success (cessation of pain) was achieved in all patients. No signs of recurrence were observed on imaging follow-up in any of the patients. One of the patients developed periprocedural right L2-L3 transient radiculopathy as major immediate complication.

CONCLUSIONS

Percutaneous image-guided cryoablation can be considered potentially safe and effective treatment for chondroblastoma and osteoblastoma in children and adolescents.

Imaging-guided radiofrequency ablation of osteoid osteoma in typical and atypical sites: Long term follow up

Purpose

To assess efficacy and safety of imaging-guided radiofrequency ablation (RFA) of Osteoid Osteoma (OO) in both typical and atypical sites.

Methods and materials

Between January 2014 and March 2019, 102 consecutive percutaneous RFA were performed and retrospectively reviewed. The procedures were performed using a RFA bipolar ablation system (Covidien, exposed tip of 0.7-1cm), under Computed Tomography (CT) guidance or using a navigation system (Masmec) under CT and Cone Beam CT (CBCT) guidance. Patients were followed up over 24 months. Clinical success and recurrences were considered on the base of established criteria. In patients with clinical failure and/or imaging evidence of relapse, retreatment was considered.

Results

Administered power per-procedure was ≤8 W (mean temperature, 90°C). The pre-procedure average value of visual analog scale (VAS) was 8.33+/-0.91. Primary and secondary success rate 96.08% (98/102) and100% (102/102), respectively. No major complication was described. Technical success was proved in every patient by CT scan acquisition after needle positioning. Relapse and tumour location were significantly correlated (p-value = 0.0165). The mean dose-length product was 751.55 mGycm2. Advanced bone healing was noted in 68 lesions after 1y-follow up and in 86 lesions after 2y-follow up.

Conclusion

Imaging-guided percutaneous RFA is a highly effective technique for OO, both in typical and atypical sites. CT or CBCT guidance, navigation systems and operator experience grant the technical success, which is the most crucial parameter affecting outcome.

Computed tomography-guided percutaneous radiofrequency and laser ablation for the treatment of osteoid osteoma - long-term follow-up from 5 to 10 years

Purpose

The impact of computed tomography (CT)-guided, percutaneous radiofrequency ablation and interstitial laser ablation (ILA) on the management of patients with osteoid osteoma was studied. This was carried out by assessing immediate and long-term clinical outcomes, the complication rate, and repeat therapy effectiveness in recurrent patients who have already experienced percutaneous ablation.

Material and methods

Consecutive patients with osteoid osteoma were assessed before the interventional treatment in a single centre from 2010 to 2015. Patient demographics, complications, and recurrence were recorded. The pain was evaluated with Visual Analogue Scale (VAS). Percutaneous procedures were performed by means of radiofrequency thermoablation or ILA. Epidural or regional anaesthesia in the CT suite was applied in all procedures. Success, whether primary or secondary, was measured as complete pain relief without evidence of recurrence after the first or second procedure, respectively. Osteoid osteoma characteristics, procedure overview, and technical success were looked for in pre-procedural and procedural scans.

Results

Eighty-three per cent of osteoid osteomas were located in lower extremities, 56% of tumours were intracortical, and 83% of osteoid osteomas were extra-articular. The mean pre-procedure VAS score was 8.5 ± 0.8, while the overall primary success rate of radiofrequency thermoablation and ILA was 87.5%. No major complications were noted. The mean follow-up period for patients in was 7.5 years (5.0-10.2 years).

Conclusions

Percutaneous, CT-guided thermoablation proved to be effective and should become the method of choice in osteoid osteoma treatment because of its minimal invasiveness. Our results show that there is no risk of very late recurrence after achieving primary and secondary treatment success.

Computed Tomography-Guided Radiofrequency Ablation of Osteoid Osteoma in Atypical Sites: Efficacy and Safety in a Large Case Series

RATIONALE AND OBJECTIVES

Although computed tomography (CT) guided radiofrequency ablation (RFA) is accepted as the gold standard treatment for osteoid osteoma (OO) in extremities, most researchers have omitted OO in critical sites. We aimed to evaluate the efficacy and safety of CT-guided RFA in the management of OO in atypical sites.

MATERIALS AND METHODS

A prospective interventional study conducted on 34 patients (12 women and 22 men; mean age, 22.3 ± 3.5 years; range, 12-48 years) with OO in atypical sites. All patients were treated with CT-guided RFA. All procedures were performed under general anesthesia using a single straight, rigid RF electrode for 6 minutes at 90°C. All patients were followed up; technical and clinical successes of treatment were evaluated. The severity of pain was assessed on a visual analogue scale (VAS).

RESULTS

CT-guided RFA was performed in all patients with 100% technical success and 100% primary clinical success. All patients had complete pain relief and returned to their quality of life without further analgesics within 1 month after the procedure. All procedures were successfully completed without any major complications. The mean preprocedure VAS score dropped to zero by the end of the first week with a highly statistically significant difference (p < 0.001).

CONCLUSION

CT-guided RFA is a safe and effective procedure in the management of OO in atypical sites with 100% primary success rate, 0% long-term recurrence rate, and very low complication rate.

Percutaneous microwave ablation of bone tumors: a systematic review

AIM

To systematically review microwave ablation (MWA) protocols, safety, and clinical efficacy for treating bone tumors.

MATERIALS AND METHODS

A systematic literature search was conducted using PubMed, the Cochrane Library, EMBASE, and Web of Science database. Data concerning patient demographics, tumor characteristics, procedure, complications, and clinical outcomes were extracted and analyzed.

RESULTS

Seven non-comparative studies (6 retrospective, 1 prospective) were included accounting for 249 patients and 306 tumors (244/306 [79.7%] metastases; 25/306 [8.2%] myelomas, and 37/306 [12.1%] osteoid osteomas [OO]). In malignant tumors, MWA power was 30-70 W (except in one spinal tumors series where a mean power of 13.3 W was used) with pooled mean ablation time of 308.3 s. With OO, MWA power was 30-60 W with mean ablation time of 90-102 s. Protective measures were very sporadically used in 5 studies. Additional osteoplasty was performed in 199/269 (74.0%) malignant tumors. Clinically significant complications were noted in 10/249 (4.0%) patients. For malignant tumors, estimated pain reduction on the numerical rating scale was 5.3/10 (95% confidence intervals [95%CI] 4.6-6.1) at 1 month; and 5.3/10 (95% CI 4.3-6.3) at the last recorded follow-up (range 20-24 weeks in 4/5 studies). For OO, at 1-month follow-up, effective pain relief was noted in 92.3-100% of patients.

CONCLUSION

MWA is effective in achieving pain relief at short- (1 month) and mid-term (4-6 months) for painful OO and malignant bone tumors, respectively. Although MWA seems safe, further prospective studies are warranted to further assess this aspect, and to standardize MWA protocols.

KEY POINTS

• Large heterogeneity exists across literature about ablation protocols used with microwave ablation applied for the treatment of benign and malignant bone tumors. • Although microwave ablation of bone tumors appears safe, further studies are needed to assess this aspect, as current literature does not allow definitive conclusions. • Nevertheless, microwave ablation is effective in achieving pain relief at short- (1 month) and mid-term (4-6 months) for painful osteoid osteomas and malignant bone tumors, respectively.

MRI patterns indicate treatment success and tumor relapse following radiofrequency ablation of osteoblastoma

Purpose: To explore the typical magnetic resonance imaging (MRI) pattern of osteoblastoma (OB) after radiofrequency ablation (RFA) treatment and to identify signs indicating treatment success or relapse.Materials and methods: Forty-four follow-up MRI examinations of 15 patients with OB who had undergone 19 RFA procedures were analyzed retrospectively. An early follow-up group (1-4 months after RFA) and a late follow-up group (8-131 months after RFA) were established. The groups were further subdivided according to treatment success. Images were analyzed for the presence of central nidus enhancement (CNE), peripheral nidus enhancement (PNE), perifocal bone marrow edema (PBME) and fatty nidus conversion (FNC).Results: The early follow-up MRI image from every patient in the treatment success group exhibited a target-like appearance with negative CNE and positive PNE or PBME. PNE and PBME were observed in 93% and 71% of the early follow-up images, respectively. A target-like appearance was observed in 25% of the late follow-up images, and PNE and PBME were each observed in 20% of these images. FNC was not observed in the early follow-up images, but was seen in 55% of the late follow-up images. All three MRI images of the patients exhibiting clinical recurrence demonstrated strong CNE, PNE and extensive PMBE, which was in contrast to the images of the patients exhibiting treatment success.Conclusion: A target-like appearance of OB in early follow-up MRI examination indicates treatment success. PNE and PBME typically reduce over time and can lead to FNC in successfully treated patients. CNE recurrence, PNE and extensive PBME are signs of relapse.

Spinal osteoid osteoma: Surgical resection and review of literature

Background:

Osteoid osteoma (OO) is a rare benign tumor of the spine that involves the posterior elements with 75% tumors involving the neural arch. The common presenting symptoms include back pain, deformity like scoliosis, and rarely radiculopathy.

Methods:

From 2011 to 2017, we evaluated cases of OO managed by posterior surgical resection while also reviewing the appropriate literature.

Results:

We assessed five patients (three males and two females) averaging 36.60 years of age diagnosed with spinal OOs. Two involved the lumbar posterior elements, two were thoracic, and one was in the C3 lateral mass. All patients underwent histopathological confirmation of OO. They were managed by posterior surgical resection with/without stabilization. No lesions recurred over the minimum follow-up period of 24 months.

Conclusion:

Surgical excision is the optimal treatment modality for treating spinal OOs. The five patients in this study demonstrated good functional outcomes without recurrences. Further, the literature confirms that the optimal approach to these tumors is complete surgical excision with/without radiofrequency ablation.

Brodie's Abscess Following Radiofrequency Ablation of an Atypical Osteoid Osteoma

A 15 years old boy presented with an atypical osteoid osteoma (OO) in distal femur. He underwent radiofrequency ablation (RFA) elsewhere. He presented to our centre a year later with persisting pain. MR scan showed incomplete ablation of the nidus as there was only a single pass of the RF probe for a 14 mm long linear lesion. We also found penumbra sign and wall enhancement on contrast MRI suggestive of a Brodie's abscess (BA). Under CT guidance the OO was drilled and BA was saucerised. Following this he was treated with culture sensitive antibiotics and his symptoms resolved. BA and OO are common differential diagnoses. RFA of OO leading to BA has not been reported in literature. Atypical linear OO requires multiple probe placements to ablate the long nidus. Diligent care should be taken to avoid intraoperative contamination in CT room which could lead to infection.

Intraarticular Osteoid Osteoma: MRI Characteristics and Clinical Presentation Before and After Radiofrequency Ablation Compared to Extraarticular Osteoid Osteoma

PURPOSE

 To determine MRI characteristics and the clinical presentation of intraarticular osteoid osteomas (OO) before and after treatment with CT-guided radiofrequency ablation (RFA) compared with extraarticular osteoid osteomas.

MATERIALS AND METHODS

 In a retrospective study, n = 21 patients with an intraarticular OO were matched with a control group of n = 21 patients with an extraarticular OO at a comparable anatomical position. All patients underwent CT-guided RFA and preinterventional MRI. In n = 31 cases, follow-up MR imaging was available. MR images were analyzed for morphologic features: effusion and synovitis, bone marrow edema (BME), soft tissue edema, periosteal reaction as well as T1 / T2 signal and contrast enhancement of the nidus. Recorded clinical parameters included the initial diagnosis, the course of pain symptoms after RFA and the incidence of complications.

RESULTS

 The nidus was detectable in all patients on MRI. BME had the highest sensitivity in both intra- and extraarticular OO (100 %). Effusion and synovitis were only observed in the intraarticular OO group (n = 21) with a perfect sensitivity and specificity (100 %) and a high negative predictive value (85 %). Soft tissue edema was significantly more present in patients with intraarticular OO (p = 0.0143). No significant differences were present regarding periosteal reaction, T1/T2 signal and contrast enhancement of the nidus (p > 0.05). BME, contrast enhancement, soft tissue edema, periosteal reaction, effusion and synovitis, if preexisting, always decreased after RFA. In 66.7 % of patients with intraarticular OO, a false initial diagnosis was made (extraarticular: 19 %). All patients were free of pain after intervention. Complications following the RFA procedure did not occur.

CONCLUSION

 MRI demonstrates the nidus and thus the OO in all cases regardless of the location. The characteristic MRI morphology of an intraarticular OO includes synovitis and joint effusion, which are always present and differentiate with perfect sensitivity/specificity from an extraarticular OO. In both intra- and extraarticular OOs pathologic MRI changes at least decreased or completely normalized and the clinical results after RFA were excellent.

KEY POINTS

  · MRI is excellently suited for the diagnosis of intra- and extraarticular OOs.. · Joint effusion and synovitis distinguish both forms with perfect sensitivity and specificity.. · All MRI changes, which indicate activity, decreased after successful RFA.. · The clinical results after RFA are excellent in both forms..

CITATION FORMAT

· Germann T, Weber M, Lehner B et al. Intraarticular Osteoid Osteoma: MRI Characteristics and Clinical Presentation Before and After Radiofrequency Ablation Compared to Extraarticular Osteoid Osteoma. Fortschr Röntgenstr 2020; 192: 1190 - 1198.

Radiofrequency ablation of atypical cartilaginous tumors in long bones: a retrospective study

Purpose: To determine the size of the ablation zone after radiofrequency ablation (RFA) of atypical cartilaginous bone tumors (ACT) using temperature-controlled 20 and 30 mm RFA straight non-cooled electrodes.Materials and methods: Sixteen patients with ACT in their long bones, who had undergone a single-session single-application CT-guided temperature-controlled RFA, were included retrospectively in the study. Tumors with a diameter of 10-25 mm were treated with 20 mm electrodes (n = 10), and tumors of 25-35 mm, with 30 mm electrodes (n = 6). The ablated zone was measured after three months on MRI images.Results: All the tumors were within the ablated zone on the 3-month follow-up MRI scan. The mean ablation time with the electrode, at a target temperature of 90 °C, was 7.6 minutes (range 6-10). The median of the largest ablation diameters, on applying the 20 and 30 mm electrodes, were 42 mm (IQR 8.5, range 30-51 mm) and 44.5 mm (IQR 4.5, range 42-63 mm), respectively.Conclusions: All the retrospectively viewed tumors in the long bones of ACT patients treated with RFA were completely ablated. The ablation zone diameters in the bones were larger than expected, when compared to other tissues, such as the liver.

[Analysis of the quality of life of patients with osteoid osteoma before and after radiofrequency ablation treatment]

BACKGROUND

The aim of this study was to investigate the effectiveness of the treatment of osteoid osteomas (OO) by radiofrequency ablation (RFA). In particular, the recurrence rate and the improvement in the quality of life as assessed by the reduction of pain intensity were evaluated.

METHODS

Retrospective analysis of 26 patients after RFA of an OO and prospective analysis of 14 patients using a self-developed quality of life questionnaire. The questionnaire, the electronic patient file and the histopathological findings were processed.

RESULTS

An average of 22 months passed between the first onset of complaints and the causative treatment by RFA. After RFA, there was a significant reduction in pain symptoms and thus an increase in the quality of life. These results confirm that RFA from OO is a safe and efficient treatment procedure.

DISCUSSION

In order to avoid long-term conservative treatment attempts and to reduce effects on the musculoskeletal system, a timely RFA of OO should be performed after diagnosis.

Safe and Effective Treatment Choice for Osteoid Osteoma: Computed Tomography-guided Percutaneous Radiofrequency Ablation

Introduction

Osteoid osteoma (OO) is a painful, benign, bone-forming tumor characterized by a small central nidus surrounded by sclerotic tissue. The aim of the present study was to evaluate the clinical outcome after computed tomography (CT)-guided radiofrequency ablation (RFA) in patients with OO performed from January 2012 to June 2018 and to confirm the safety and efficacy of CT-guided RFA.

Methods

Between January 2012 and June 2018, a total of 63 patients were treated with CT-guided RFA. Pre- and post-treatment pain, further treatment after the RFA procedure, observed complications, and satisfaction with the treatment were recorded for an assessment of clinical effects in all patients. The patients were evaluated with the visual analog scale (VAS) pre-procedure and at three months post-procedure.

Results

Of the patients, 39 were males and 24 were females with a mean age of 21 ± 9.7 (range, 9 to 41) years. The mean follow-up was 16 ± 2.1 (range, 12 to 19) months. The mean duration of the procedure was 34 ± 11.4 (range, 22 to 47) min. All of the patients were diagnosed with OO pathologically. A statistically significant difference was found between the pre-procedural and post-procedural VAS scores (p<0.001). Complications were observed in six patients including one peroneal nerve lesion, three minor skin burns, and two minor skin infections.

Conclusion

This study shows that CT-guided RFA is a safe and effective treatment for OO. It is thought that RFA could be the primary treatment choice for most OO with typical symptoms and radiological findings.

Complications of Computer Tomography Assisted Radiofrequency Ablation in the Treatment of Osteoid Osteoma

Background

Osteoid osteoma (OO) is one of the most commonly occurring benign bone tumors. It constitutes 10-12% of benign bone tumors and 2-3% of primary bone tumors. In radiofrequency ablation (RFA) treatment, the cells of the tumor are thermally inactivated by the help of electrodes shaped like needles. In our study, we aimed to show the major and minor complications in patients undergoing RFA and to show what should be done to prevent these complications.

Methods

The study was carried out as a prospective study on the follow-up of 87 osteoid osteoma patients treated between 2015 and 2017. The youngest of the patients was 1 year old and the oldest was 42 years old. The RFA procedure lasted 10 min on average, excluding anesthesia and preparation. All lesions were ablated at 90 degrees for 7 minutes with the heat increased gradually. All patients were followed up for 1 day in the orthopedics clinic.

Results

Complications were observed in 7 patients. The lesions with the most complications were observed to be in the tibia, second-degree burns were seen in 2 patients, and superficial skin infection was observed in 2 patients. In 1 patient, the probe tip was broken and remained within the bone. Intramuscular hematoma was detected in 1 lesion located in the proximal femur. A complaint of numbness in the fingers developed in a lesion located in the metacarpus.

Conclusion

Preventive measures should be taken before the procedure in order to prevent minor complications, and, for major complications, close follow-up should be done after the procedure and patients should be kept away from heavy physical activities for the first 3 months.

Percutaneous radiofrequency ablation versus open surgical resection for spinal osteoid osteoma

BACKGROUND CONTEXT

Both open surgical resection (OSR) and radiofrequency ablation (RFA) have been reported for spinal osteoid osteoma (OO).

PURPOSE

To verify the clinical safety and efficiency of RFA with OSR in treating spinal OO.

STUDY DESIGN

Retrospective cohort study.

PATIENT SAMPLE

Twenty-eight consecutive patients with spinal OO who underwent either RFA or OSR in our institute between September 2006 and December 2016.

OUTCOME MEASURES

The age, gender, lesion distribution, surgical time, estimated blood loss, complications, local recurrence, visual analogue scale (VAS), and the modified Frankel grade were documented.

METHODS

We retrospectively reviewed 28 patients with spinal OO who had been treated in our hospital from September 2006 to December 2016. Patients were followed at 3, 6, 12, and 24 months after the index surgery. The minimum follow-up period was 12 months. This study was funded by Peking University Third Hospital (Y71508-01) (¥ 400,000).

RESULTS

Twelve and 16 patients were treated with CT-guided percutaneous RFA and OSR, respectively. Spinal OO locations were cervical in 4, thoracic in 4, lumbar in 3, and sacral vertebra in 1 in the RFA group and cervical in 12, thoracic in 1, and lumber in 3 in the OSR group. RFA showed shorter operating time, less blood loss, and less in-hospital stay than open surgery [105.0 ± 33.8 minutes vs. 186.4 ± 53.5 minutes (p < .001), 1 (0 to 5) ml vs. 125 (30-1200) ml (p < .001) and 1 (1-3) days vs. 6 (3-10) days (p < .001), respectively]. At last follow-up, one patient underwent a secondary RFA for recurrence. VAS improvement was 7.5 (3-10) and 6.5 (4-9) (p = .945) in the RFA and OSR groups, respectively. The overall complication rate was 8.3% (1/12) and 18.8% (3/16) in the RFA and OSR groups, respectively.

CONCLUSIONS

If there is sufficient cerebrospinal fluid between the spinal OO lesion and spinal cord/nerve root (more than 1 mm), RFA is effective and safe for treatment of well-selected spinal OO, showing reduced operating time, blood loss, in-hospital stay, and complications compared to OSR. However, OSR is still recommended in cases with spinal cord/nerve root compression.

Successful Management Of Tumor-Induced Osteomalacia with Radiofrequency Ablation: A Case Series

Tumor-induced osteomalacia (TIO) is a curable condition when the tumor is correctly located and completely removed. These tumors are, however, small and located in regions that make surgical removal difficult and sometimes risky in some patients. Experience of radiofrequency ablation (RFA) in the management of TIO is limited. We describe 3 patients with TIO who were treated in our hospital with RFA. They had suspected lesions in surgically difficult locations and were subjected to single sessions of RFA. The response was documented in terms of improvement in symptoms, normalization of hypophosphatemia and hyperphosphaturia, and disappearance of uptake on follow-up Ga⁶⁸ DOTANOC PET/CT imaging. All 3 patients had a clinical and biochemical profile consistent with TIO. The first patient (patient 1) had an intensely Ga⁶⁸ DOTANOC avid lesion involving the roof of right acetabulum. The second patient (patient 2) had a Ga⁶⁸ DOTANOC avid intramuscular lesion in left pectineus muscle and the third patient (patient 3) had a Ga⁶⁸ DOTANOC avid expansile osteolytic lesion involving the angle and ramus of right mandible. All 3 patients achieved complete biochemical as well as clinical remission with single sessions of RFA. Six months after the procedure, Ga⁶⁸ DOTANOC imaging revealed the absence of uptake at the previous sites, corroborating with the clinical improvement and normalization of hypophosphatemia and hyperphosphaturia. In conclusion, although surgical resection is the standard of care, RFA can be used successfully for treating patients with TIO. It can be an effective, less invasive, and safe modality of treatment in those patients where resection of the lesion is not possible because of inaccessible anatomical location or comorbidity that prohibits surgery. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

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.

Cystic bone tumors of the foot and ankle

Bone tumors are relatively rare in the foot and ankle region. Many of them present as cystic lesions on plain films. Due to the relative rarity of these lesions and the complex anatomy of the foot and ankle region, identification of such lesions is often delayed or they get misdiagnosed and mismanaged. This review discusses the most common cystic tumors of the foot and ankle including their radiographic features and principles of management.

Percutaneous Radiofrequency Ablation for the Treatment of Osteoid Osteoma in Children and Adults: A Comparative Analysis in 92 Patients

PURPOSE

To compare technical success, complications, and long-term clinical success following radiofrequency ablation of osteoid osteomas in pediatric and adult patients.

MATERIALS AND METHODS

Ninety-two patients underwent percutaneous computed tomography-guided radiofrequency ablation for osteoid osteomas including 54 pediatric (mean age 12.9 years) and 38 adult (mean age 24.1 years) patients. Presenting indication, osteoma location, ablation method, technical success, complications, visual analog score, radiographic follow-up, clinical success, reintervention rate, and total follow-up were reported. Technical success was defined as placement of the probe in the radiolucent nidus with ablation. Clinical success was defined as resolution of symptoms.

RESULTS

Ablation indications included: pain localized to the lesion, night pain, and an osteoma on imaging in all patients. Majority of osteoid osteomas were localized to the femur (pediatric [n = 22, 40.7%]; adult [n = 12, 34.2%]) and tibia (pediatric [n = 21, 38.9%]; adult [n = 10, 26.3%]). Mean lesion size was 9.6 mm in pediatric patients and 9.0 mm in adults. Technical success was achieved in all pediatric patients (100%) and 97.4% of adults. Two complications occurred. Primary clinical success was achieved in 49 (90.7%) pediatric and 35 (92.1%) adult patients. Five (9.3%) pediatric and 3 (7.9%) adult patients sought reintervention for residual symptoms, and all had secondary clinical success. Mean total follow-up was 95.2 ± 58.7 months in pediatric and 90.0 ± 61.6 months in adult patients. No differences in outcomes were identified between pediatric and adult patients.

CONCLUSION

Radiofrequency ablation of osteoid osteomas is safe with excellent technical and clinical success rates in pediatric and adult patients.

Neoadjuvant denosumab for the treatment of a sacral osteoblastoma

PURPOSE

To present a case of aggressive sacral osteoblastoma (OB) treated with neoadjuvant denosumab therapy and en bloc resection.

METHODS

Case report of a 14-year-old male with an aggressive OB affecting the superior articular process of the left first sacral segment. The lesion was lytic and metabolically active and involved the left-sided posterior elements of S1-S3 with extension into the spinal canal, affecting the left S1, S2, S3, S4 and S5 nerve roots. He was treated for 1 month with neoadjuvant denosumab followed by en bloc resection.

RESULTS

Denosumab therapy caused regression of the tumour and converted the diffuse infiltrative mass into a well-defined solid (osteoma-like) structure, aiding surgical resection and preserving the S1, S4 and S5 nerve roots. Histologically, the treated lesion showed abundant sclerotic woven bone and osteoblasts with absence of osteoclasts.

CONCLUSIONS

A short course of denosumab caused tumour regression, ossification and conversion of an aggressive OB into a sclerotic, well-defined lesion thus aiding surgical resection and preservation of neural structures. Neoadjuvant therapy reduced osteoclast numbers but PET showed that the lesion remained FDG avid post-therapy.

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

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

Minimal invasive intralesional excision of extremity-located osteoid osteomas in children

In this retrospective study, we evaluated the efficiency of minimal invasive intralesional extended curettage in the treatment of osteoid osteomas of the extremities in children. Forty-seven children (29 males, 18 females; mean age 10.5 years; range 4-19 years) with osteoid osteoma of the extremities underwent minimal invasive intralesional extended curettage. The exact localization of the nidus was determined preoperatively by thin-section (1-1.5 mm) computed tomography scans, and complete excision of the nidus was performed using a modified burr-down technique. None of the procedures required bone grafting or internal fixation. The median follow-up duration was 59 months (range, 12-136 months). Histopathological confirmation of osteoid osteoma was achieved in all procedures. All patients experienced immediate and complete relief of lesional pain after surgery. Preoperative (a day before surgery) and postoperative (at the time of discharge) mean visual analogue scale scores, questioning the pain derived from osteoid osteoma, were 7.7±1.2 and 0.3±0.6, respectively, confirming complete removal of the nidus. Early motion of the involved extremities and mobilization of the patients were achieved within 2 days. The children resumed normal function within 3 weeks. Postoperative complication or recurrence was not encountered in any of the patients. Even though percutaneous radiofrequency thermoablation is accepted as the treatment of choice for extraspinal osteoid osteomas, this technique requires a regional reference institution. Minimal invasive intralesional extended curettage can be performed in conventional institutions, even those not specialized in bone tumor surgery, by orthopedic surgeons with high success and low morbidity rates, in addition to rapid functional recovery.

[Postoperative and posttherapeutic changes after primary bone tumors : What's important for radiologists?]

Posttreatment imaging of primary bone tumours represents a diagnostic challenge for radiologists. Depending on the primary bone tumour common radiological procedures, such as radiography, computed tomography (CT), and magnetic resonance imaging (MRI), are employed. Radiography and CT are particularly useful in benign bone tumours and in matrix-forming bone tumours. MRI comes into consideration with malignant tumour recurrence and tumoral soft tissue infiltration. Bone scintigraphy is of superior importance if a primarily multifocal manifestation of bone tumour or metastasizing tumour disease is suspected. Molecular imaging (FDG-PET and hybrid imaging, using CT) are gaining increasing importance in light of monitoring neoadjuvant chemotherapy and detecting recurrent tumour appearance. The current literature shows sensitivity and specificity values for recurrent detection of up to 92% and 93%. Diagnostic accuracy is as high as 95%, thus, exceeding accuracy values for CT (67%) and MRI (86%) by far. Likewise, this is also applicable for the assessment of the neoadjuvant chemotherapy. Moreover, PET-based modalities are able to establish prognostic statements using SUV-threshold values at baseline (especially for Ewing sarcomas). Advanced imaging techniques have made a great diagnostic step forward and have proven to be relevant and reproducible with respect to both relapse detection and treatment assessment. Furthermore, it is not clear whether a higher detection rate of early tumour recurrence will inevitably lead to better outcome and survival.

[The intraarticular osteoid osteoma : A diagnostic and therapeutic challenge]

Intra- and, respectively, periarticular osteoid osteoma are accompanied by sympathical arthritis which itself can irreversibly destroy the cartilage of the joint. In contrast to other locations, intra- and periarticular osteoid osteoma are rare. Reactive and symptomatic accompanying arthritis may lead to irreversible cartilage destruction especially in chronic courses. Therefore early diagnosis and therapy is crucial. We present a case report and discuss these rare tumors by reviewing the literature.

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

STUDY DESIGN

Retrospective. Level IV Evidence.

OBJECTIVE

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

SUMMARY AND BACKGROUND DATA

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

Level IV.

Spinal osteoid osteoma: efficacy and safety of radiofrequency ablation

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Therapeutic outcome of CT-guided radiofrequency ablation in patients with osteoid osteoma

OBJECTIVE

To assess the long-term outcome of computed tomography-guided radiofrequency ablation (CT-guided RFA) in patients with suspected osteoid osteoma (OO).

MATERIALS AND METHODS

Single-center retrospective study. Patients with clinical suspicion and imaging diagnosis of osteoid osteoma were treated by CT-guided RFA using the same device with either a 7- or 10-mm active tip electrode. Specific precautions were applied in case of articular or spinal OO. Patients were contacted by phone to evaluate the long-term outcome in terms of pain, ability to perform daily activities (including sports), and long-term complications. Success was defined as the absence of residual pain and ability to perform daily activities normally.

RESULTS

From 2008 to 2015, 126 patients were treated by CT-guided RFA for OO in our institution. Mean patient age was 26.1 years (SD = 11, range 1-53); mean delay to diagnosis was 16.9 months (SD = 15.2, range 1-120). Among patients who answered the follow-up call (n = 88), the overall success rate was 94.3%: 79/88 (89.8%) had primary success of the procedure, and 4/88 (4.5%) had a secondary success (repeat-RFA after pain recurrence). Mean follow-up time was 34.6 months (SD = 24.7, range 3-90). Few complications occurred: two mild reversible peripheral nerve injuries, one brachial plexus neuropathy, one broken electrode tip fragment, and one muscular hematoma.

CONCLUSION

Osteoid osteoma can be effectively and safely treated by CT-guided RFA using the presented ablation protocol. Beneficial effects of the treatment persist at long-term follow-up.

Osteoblastoma of the elbow: analysis of 13 patients and literature review

PURPOSE

To analyze the clinical and radiographic characteristics, treatment, and outcome of patients with elbow osteoblastoma.

PATIENTS AND METHODS

We present 13 patients (7 males and 6 females; mean age, 28 years) diagnosed and treated for an elbow osteoblastoma from 1975 to 2012. Mean follow-up was 29 months (range 12-60 months). Clinical presentation, imaging, surgical treatment, complications, range of elbow motion, and functional outcome were evaluated. The MSTS, DASH, and OXFORD scores were used.

RESULTS

Main symptom was pain (all patients) accompanied by stiffness (8 patients) and swelling or tumefaction (7 patients), with a median duration of symptoms of 32 months (range 6-96 months). Distal humerus was affected in 10 patients, proximal ulna in 2 patients, and proximal radius in one patient. All patients underwent surgical therapy that consisted of curettage of the lesion (7 patients), curettage and bone allografting (3 patients), wide resection (2 patients; total distal humerus and resection of the radial head), and radiofrequency thermal ablation (1 patient). One patient experienced a recurrence after surgical treatment. The mean MSTS score after treatment was 87% (range 50-100%), which corresponds to excellent results.

CONCLUSIONS

Intralesional surgery is successful in tumor control in most patients with osteoblastoma of the elbow. Thermal ablation may be successful for smaller lesions. Most of the patients had a good-to-excellent functional outcome even if they had tumor-related elbow stiffness at diagnosis.

LEVEL OF EVIDENCE

Therapeutic study, Level IV-1.

CT-guided radiofrequency ablation of spinal osteoblastoma: treatment and long-term follow-up

OBJECTIVE

Osteoblastoma (OB) is a painful, rare, benign bone tumour usually observed in young populations, and this condition involves the spine in up to one-third of cases. We sought to focus on the minimally invasive treatment of spinal OB with radiofrequency ablation (RFA) under computed tomography (CT) guidance. When performed near the spinal cord, surgery can lead to instability of the spine, sometimes requiring additional interventions to stabilise the segments involved, and can cause the precocious onset of arthrosis or other degenerative diseases. The results were evaluated both clinically and with the aid of diagnostic imaging techniques during a 5-year follow-up study.

MATERIALS AND METHODS

Eleven patients affected by spinal OB were treated in a single session with biopsy and CT-guided RFA. Pre- and post-evaluations of the patients were performed both clinically and with CT and magnetic resonance imaging (MRI).

RESULTS

Complete success in terms of pain relief was achieved in all patients. Additional treatments were not required in any patients. There were no complications. During follow-up, neither complications nor pathological findings related to the treatment were observed.

CONCLUSIONS

Our experience demonstrates that RFA for spinal OB is safe and effective. One of the main advantages of this technique is represented by its lower grade of invasiveness compared with that for potentially hazardous surgical manoeuvres.

Pediatric Percutaneous Osteoid Osteoma Ablation: Cone-Beam CT with Fluoroscopic Overlay Versus Conventional CT Guidance

PURPOSE

To compare technical success, clinical success, complications, radiation dose, and total room utilization time for osteoid osteoma thermal (radiofrequency or microwave) ablation using cone-beam computed tomography (CBCT) with two-axis fluoroscopic navigational overlay versus conventional computed tomography (CT) guidance.

MATERIALS AND METHODS

A retrospective review was performed to identify all osteoid osteoma ablations performed over a 5.5-year period at a single tertiary care pediatric hospital. Twenty-five ablations (15 radiofrequency and 10 microwave) in 23 patients undergoing fluoroscopic CBCT-guided osteoid osteoma ablation were compared to 35 ablations (35 radiofrequency) in 32 patients undergoing ablation via conventional CT guidance. Dose area product and dose length product were recorded for CBCT and conventional CT, respectively, and converted to effective doses. Technical success, clinical success (cessation of pain and medication use 1 month after ablation), complications, radiation dose, and total room utilization time were compared.

RESULTS

All procedures were technically successful. Twenty-two of 25 (88.0%) CBCT and 31 of 35 (88.6%) conventional CT-guided ablations achieved immediate clinical success. There were two minor complications in each group and no major complications. Mean effective radiation dose was significantly lower for CBCT compared to CT guidance (0.12 vs. 0.39 mSv, p = 0.02). Mean total room utilization time for CBCT was longer (133.5 vs. 97.5 min, p = 0.0001).

CONCLUSIONS

Fluoroscopic CBCT guidance for percutaneous osteoid osteoma ablation yields similar technical and clinical success, reduced radiation dose, and increased total room utilization time compared to conventional CT guidance.

[Diagnostics and treatment of benign spinal tumors]

Benign tumors of the spine are rare and may lead to unspecific back pain. The classification of the lesion is typically achieved with a combination of imaging techniques (MRI and CT scans) and, in some cases, a histological sampling to allow differentiation from malignant processes. Both open and interventional (CT guided) biopsies are possible, depending on the localization of the tumor. Treatment strategies are diverse, require an interdisciplinary approach, and include operative and interventional procedures. The following article gives an overview of the most important benign tumors of the spine, the typical features in imaging, and treatment strategies.

Benign Spine Lesions: Advances in Techniques for Minimally Invasive Percutaneous Treatment

Minimally invasive percutaneous imaging-guided techniques have been shown to be safe and effective for the treatment of benign tumors of the spine. Techniques available include a variety of tumor ablation technologies, including radiofrequency ablation, cryoablation, microwave ablation, alcohol ablation, and laser photocoagulation. Vertebral augmentation may be performed after ablation as part of the same procedure for fracture stabilization or prevention. Typically, the treatment goal in benign spine lesions is definitive cure. Painful benign spine lesions commonly encountered in daily practice include osteoid osteoma, osteoblastoma, vertebral hemangioma, aneurysmal bone cyst, Paget disease, and subacute/chronic Schmorl node. This review discusses the most recent advancement and use of minimally invasive percutaneous therapeutic options for the management of benign spine lesions.