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

Time-Driven Activity-Based Cost Comparison of Osteoid Osteoma Ablation Techniques

OBJECTIVE

Compare the cost of performing an osteoid osteoma ablation using cone beam CT (CBCT) with overlay fluoroscopic guidance to ablation using conventional CT (CCT) guidance and microwave ablation (MWA) to radiofrequency ablation (RFA).

METHODS

An 11-year retrospective study was performed of all patients undergoing osteoid osteoma ablation. Ablation equipment included a Cool tip RFA probe (Covidien, Minneapolis, Minnesota) or a Neuwave PR MWA probe (Ethicon, Rariton, New Jersey). The room times as well as immediate recovery time were recorded for each case. Cost analysis was then performed using time-driven activity-based costing for rate-dependent variables including salaries, equipment depreciation, room time, and certain supplies. Time-independent costs included the disposable interventional radiology supplies and ablation systems. Costs were reported for each service providing care and using conventional cost accounting methods with variable and fixed expenditures.

RESULTS

A total of 91 patients underwent 96 ablation procedures in either CBCT (n = 66) or CCT (n = 30) using either MWA (n = 51) or RFA (n = 45). The anesthesia induction (22.7 ± 8.7 min versus 15.9 ± 7.2 min, P < .001), procedure (64.7 ± 27.5 min versus 47.3 ± 15.3 min; P = .001), and room times (137.7 ± 33.7 min versus 103.9 ± 22.6. min; P < .001) were significantly longer for CBCT procedures. The procedure time did not differ significantly between MWA and RFA (62.1 ± 27.4 min versus 56.1 ± 23.3 min; P = .27). Multiple regression analysis demonstrated lower age (P = .046), CBCT use (P = .001), RFA use (P = .02), and nonsupine patient position (P = .01) significantly increased the total procedural cost. After controlling for these variables, the total cost of CBCT ($5,981.32 ± $523.93 versus $5,378.93 ± $453.12; P = .001) remained higher than CCT and the total cost of RFA ($5,981.32 ± $523.93 versus $5,674.43 ± $549.14; P = .05) approached a higher cost than MWA.

CONCLUSION

The use of CBCT with overlay fluoroscopic guidance for osteoid osteoma ablation resulted in longer in-room times and greater cost when compared with CCT. These cost considerations should be weighed against potential radiation dose advantage of CBCT when choosing an image guidance modality. Younger age, RFA use, and nonsupine patient position additionally contributed to higher costs.

Intraoperative cone-beam computed tomography-guided curettage for osteoid osteoma

Recently, cone-beam computed tomography (CBCT)-guided surgeries have been developed for bone and soft tissue tumors. The present study aimed to evaluate the efficacy of CBCT-guided curettage for osteoid osteoma. Our study population included 13 patients who underwent primary curettage for osteoid osteoma using intraoperative CBCT in a hybrid operating room between April 2019 and November 2022. We collected the following data: sex, age, follow-up period, symptom onset to time of surgery, tumor size and location, length of skin incision, operating time, radiation dose, recurrence, postoperative complications, and visual analog scale for pain during the last follow-up. There were 10 male and 3 female patients, and the mean age was 25.0 years (range, 9-49 years). The mean follow-up period was 10.6 months (range, 0.4-24.0 months). The locations of the tumors were the proximal femur in 6 patients, the acetabular region in 2 patients, and the ilium, tibial shaft, calcaneus, cuboid, and talus in 1 patient each. The mean time of symptoms onset to surgery was 18.7 months (range, 2.3-69.9 months). The mean maximum diameter of the tumor was 5.9 mm (range, 3.5-10.0 mm). The mean length of the skin incision was 2.2 cm (range, 1.5-3.5 cm). The mean operating time was 96.9 minutes (range, 64-157 minutes). The mean dose of radiation was 193.2 mGy (range, 16.3-484.0 mGy). No recurrences, postoperative complications, and reoperation were observed in this study. All the patients reported 0 mm on the visual analogue scale for pain on the last follow-up. CBCT-guided curettage for osteoid osteoma was minimally invasive and reliable. This procedure can be effective for the treatment of lesions found in deep locations such as the pelvic bone and proximal femur or an invisible lesion that cannot be detected by regular fluoroscopy.

Rationale for fluoroscopic guidance in spine injections

Spine injections are commonly performed in the treatment of back pain. The purpose of this article is to review the current literature surrounding image guided spine injections focusing on scenarios where fluoroscopic guidance can be advantageous in addition to discussing similarities among the different modalities.

Diagnosis and Management of Craniofacial Osteomas

IMPORTANCE

Osteoid osteomas are benign bony overgrowths that can occur in any region of the body. However, they have a predilection to occur in the craniofacial region. Because of the rarity of this entity, there is a lack of literature detailing the management and prognosis of craniofacial osteoid osteomas.

OBSERVATIONS

Craniofacial osteomas have a predilection to involve the paranasal sinuses, but can also be found within the jaw, skull base, and facial bones. Because of their slow-growing nature, craniofacial osteomas are often incidentally discovered on routine imaging or after they compress nearby structures or distort nearby anatomy. Osteoid osteomas of the face can be treated with resection via various approaches. Recent advancements describe minimally invasive endoscopic techniques and adjuvant therapy with radiofrequency ablation guided by cone biopsy computed tomography. Osteoid osteomas have an excellent prognosis with complete resection. They demonstrate a low incidence of recurrence when compared with other osteoblastic lesions of the craniofacial structures.

CONCLUSIONS AND RELEVANCE

Craniofacial osteoid osteomas remain a developing topic within the field of craniofacial surgery. Their removal may be trending toward minimally invasive techniques. However, all treatment modalities appear to result in improved cosmetic outcomes and low recurrence rates.

Cone-beam computed tomography-assisted percutaneous gastrostomy tube insertion in children with challenging anatomy

BACKGROUND

Percutaneous radiological gastrostomy tube insertion is a common procedure in children. An approach using ultrasound and fluoroscopy may not be feasible in patients with challenging anatomy; therefore, advanced techniques or other imaging modalities may be required.

OBJECTIVE

To describe our experience using cone-beam computed tomography (CT)-assisted percutaneous gastrostomy insertion in pediatric patients with challenging anatomy.

MATERIALS AND METHODS

A retrospective review was performed in children who underwent cone-beam CT-assisted percutaneous radiologic gastrostomy between January 2015 and July 2019. Indications, technique, outcomes, complications, and radiation dose (reference-point air kerma, air kerma area product) were assessed through chart and imaging review. Descriptive statistics only were used.

RESULTS

Twenty-seven procedures were attempted in 26 patients. Reasons for utilizing cone-beam CT guidance were high-positioned stomach (n = 10), interposing bowel loops and liver (n = 19), omphalocele (n = 1), severe scoliosis (n = 1), and ventriculoperitoneal shunt (n = 1). Technical success was 85% (23/27). Mean procedure time was 96 min (range 50-131 min). No safe access route into the stomach was encountered in four patients; three were referred for surgical gastrostomy and one had a successful re-attempt. Radiation dose data was obtained from 19 procedures (17 successful) with a total dose in successful procedures ranging from 8.1 to 63.6 mGy (average 26.2 mGy, median 24.9 mGy). The number of cone-beam CT acquisitions per procedure ranged from 1 to 4. Major complication frequency was 11% (3/27) (bleeding, peritonitis, and aspiration pneumonia); minor complication frequency was 3.7% (1/27).

CONCLUSION

This study shows that cone-beam CT guidance can be useful for assisting percutaneous radiologic gastrostomy in children with challenging anatomy.

CT-Guided Radiofrequency Thermal Ablation for the Treatment of Atypical, Early-Onset Osteoid Osteoma in Children Younger than 4 Years Old: Single-Institution Experience and Literature Review

The aim of our study is to report our experience on CT-guided radiofrequency ablation (RFA) for osteoid osteoma (OO) in children under 4 years of age and to review the literature regarding this atypical, early onset of the disease. We retrospectively reviewed the clinical and radiological records of the patients treated with CT-guided RFA for OO at our institution (2006−2021), including those under 4 years of age. Data regarding technical success, clinical success, and biopsy diagnostic yield were collected. Moreover, we performed a literature review including previous articles on early-onset OO. We found only 12 patients that were under 4 years of age (12/842−1.4%) at the time of RFA treatment: 4 F and 8 M, mean age at the time of the treatment 35.3 months (range 22−46 months). The mean follow-up was 22.8 months (range 6−96 months). Technical success was achieved in all cases (12/12). In all patients (12/12), a complete remission of the pain symptoms was achieved at clinical follow-up controls. No recurrence of pain or complications were documented. The histopathological diagnosis was confirmed in 4 patients (4/12−33.3%). Moreover, we found another 9 articles in the literature with a main focus on early-onset OO (<4 years old), with a total of 12 patients included; 6 of those patients (6/12−50%) were treated with CT-guided RFA, with success reported 5 cases (5/6−83.3%). Our series of cases treated at a single institution, together with the existing data from the literature, confirms that CT-guided RFA is effective and safe for the treatment of osteoid osteoma, even in atypical, early onset in children under 4 years of age.

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

INTRODUCTION

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

MATERIAL AND METHOD

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

RESULTS

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

CONCLUSIONS

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

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.

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.

Percutaneous Core Needle Biopsy: Considerations in the Pediatric Patient

Image-guided percutaneous biopsy is the cornerstone of solid tissue diagnosis. The ability to safely sample tissue in locations that previously required surgery or necessitated empiric therapy has allowed for more personalized treatment options, as well as more rapid development of novel therapeutics. In children, these same advantages are accompanied by a smaller margin for error and rapidly expanding indications. The intent of this review is to outline the role of image-guided biopsy in the management of childhood disease, how this role is changing, and the practical aspects of managing and performing pediatric biopsies.

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.

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.

XperCT Sharpening Reconstruction for Cone-Beam Computed Tomography Guided Lung and Bone Interventions

C-arm cone-beam computed tomography (CBCT) is a valuable tool for three-dimensional navigation and mapping in the interventional radiology suite owing to its flexible gantry positioning, real-time three-dimensional volume acquisition, and reduced contrast and radiation use. Reports of CBCT-guided bone and lung interventions are relatively infrequent, however, possibly due in part to the lack of dedicated bone and lung reconstruction algorithms and concerns regarding insufficient lesion conspicuity. Two cases of an ad hoc intraprocedural CBCT sharpening reconstruction are presented in this article.

3D imaging and stealth navigation instead of CT guidance for radiofrequency ablation of osteoid osteomas: a series of 52 patients

Background

Osteoid osteomas are benign bone neoplasms that may cause severe pain and limit function. They are commonly treated by radiofrequency ablation (RFA) through a needle inserted into the nidus of the lesion under CT guidance, which is associated with exposure of young patients to relatively high dose of radiation. The objective of this study was to investigate the amount of radiation, effectiveness and safety of an alternative imaging approach, the 3D image-guided (O-arm) technology and the Stealth navigation.

Methods

We retrospectively reviewed 52 electronic medical files of patients (mean age 24.7 years, range 8–59 years) who were treated with thermal ablation of benign osteoid osteomas guided by the navigated O-arm-assisted technique in our institution between 2015 and 2017. Data were extracted on the associated complications, the reduction in pain at 3 months and one year postoperatively, and the amount of radiation administered during the procedure.

Results

The level of pain on a visual analogue scale decreased from the preoperative average of 7.73 to 0 at the 3-month follow-up. The mean dose-length product was 544.7 mGycm² compared to the reported radiation exposure of 1971–7946 mGycm² of CT-guided radio ablations. The one intra-operative complication was a superficial burn in the subcutaneous lesion in a tibia that was treated locally with no major influence on recovery.

Conclusions

RFA ablation guided by 3D O-arm stealth navigation is as effective as the traditional CT-guided technique with the advantage of lower radiation exposure.

Trial registration

Retrospective study number 0388–17-TLV at Tel Aviv Sourasky Medical Center IRB, approved at 25.10.17.

Osteoid Osteoma in Children Younger than 3 Years of Age

We present a case series of four children, younger than 3 years old, with osteoid osteoma of the lower limb. Pain and limping were the main symptoms. With careful clinical examination, we could localize the affected area. Radiological evaluation revealed cortical thickening in 3 children. On MRI examination, we found extensive edema, with normal bony cortices. The central nidus was found in 3 children. CT scan was the most accurate examination which revealed the central nidus with surrounding sclerosis. Bone scans had positive uptake in the affected area. Our patients were treated with an intralesional excision biopsy, with simultaneous radiofrequency ablation in those affected in the femur. Pathological specimens confirmed the diagnosis of osteoid osteoma. There was uneventful recovery of our patients. This case series contributes to the limited description of osteoid osteoma diagnosed and treated in very young children.

Percutaneous image-guided ablation: From techniques to treatments

Image-guided ablation is performed by percutaneously introducing ablation probes to deliver energy into a tumor to destroy it in a controlled and localized fashion. Ablation modalities can be broadly classified as thermal or non-thermal based on the mechanism of tumor destruction and are performed using different types of image guidance for planning, delivering and follow-up of the treatment. Ablation is performed in a minimally invasive fashion, providing greater residual organ preservation with minimal morbidity to the patient. Image-guided ablation is being used in the clinic for the treatment of primary and metastatic tumors, and this article reviews state of the art for the treatment of malignancies in the liver, lung, kidney and musculoskeletal tissue.

C-arm cone-beam computed tomography-guided minimally invasive open excision of an osteoid osteoma undetectable on fluoroscopy: A case report

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A robotic C-arm cone-beam computed tomography (CBCT) system provides a clear intraoperative visualization of the osteoid osteoma.

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C-arm CBCT allowed precise access to the tumor, accurate tumor resection, and minimal sacrifice of the normal bone in osteoid osteoma surgery.

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Repurpose use of the dilator, retractor, and wider trephine tips achieved more conservative results with a smaller skin incision.

Introduction

The small size of a nidus and the extensive sclerosis around it often make it difficult to identify tumors from the surrounding normal bone by fluoroscopy, and a large amount of bone resection might be required to secure complete removal during osteoid osteoma surgery. In this report, we present the first case of radiographically invisible osteoid osteoma that was successfully resected under a robotic C-arm cone-beam computed tomography (CBCT) imaging system.

Presentation of case

A 14-year-old boy presented with persistent pain around the left knee joint was diagnosed with osteoid osteoma of the left distal femur. Since the tumor was not detectable by intraoperative fluoroscopy, a CBCT system was used for guidance during an open tumor resection. For a less invasive surgery, we repurposed the dilator and retractor of the microendoscopic discectomy (MED) system and resected the tumor using the wider trephine tips for bone biopsy. At the final follow-up one year later, the function of the afflicted limb was normal with no complaint of any symptoms. Plain radiograph at the final follow-up showed new bone formation completely filling the bone defect, without local recurrence.

Discussion

CBCT allowed for clear intraoperative visualization of the osteoid osteoma, thereby promising a secure resection and less invasive osteoid osteoma treatment. Furthermore, the repurposed use of the dilator and retractor of the MED system as well as the wider trephine tips for bone biopsy made the procedure less invasive.

Conclusion

CBCT-guided minimally invasive open excision surgery could be a useful option for the management of radiographically invisible osteoid osteoma.

Cryotherapy of acetabular osteoid osteoma under fluoroscopic guidance using the XperGuide System

Osteoid osteoma represents 10%-12% of all benign bone tumors, and is composed by osteoid tissue and reticular and immature bone tissue. Acetabular involvement is very rare (≤1%). In this case report, we describe the treatment of an osteoid osteoma of the acetabulum of a young man using cryotherapy under fluoroscopic guide with the new XperGuide system which is used to reduce X-ray radiation dose and to have a more accurate localization of the lesion compared to computed tomography-guided or surgical ablation.

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.

Cone-beam computed tomography guidance with navigational overlay for percutaneous lung nodule biopsy

BACKGROUND

Cone-beam CT is increasingly used in pediatric interventional radiology procedures. However, the feasibility or safety of using this mode of imaging guidance for percutaneous lung nodule biopsy in children has not been assessed.

OBJECTIVE

To retrospectively evaluate safety and diagnostic accuracy of percutaneous lung nodule biopsy in people treated at a pediatric hospital using cone-beam CT with navigational overlay.

MATERIALS AND METHODS

Thirty-six consecutive patients from two large tertiary-care children's hospitals with lung nodules of 48 mm or smaller underwent percutaneous lung nodule biopsy using cone-beam CT with navigational overlay. We evaluated patient demographics, pre- and post-biopsy diagnoses, number of biopsy passes, complications, radiation exposure and technical success.

RESULTS

Percutaneous lung nodule biopsy was performed for 37 nodules in 36 patients (23 males, 13 females, median age 15.5 years, range 8 months to 23 years). One patient underwent biopsy of two nodules at a single procedure. Median patient weight was 55 kg (range 8-97 kg). Pre-biopsy diagnoses included metastatic sarcoma or other solid tumor (n=11), leukemia/lymphoma (n=13), infection (n=10), chronic granulomatous disease (n=2) and post-transplant lymphoproliferative disorder (PTLD; n=1). Mean number of passes was 5 (range 2-15). Mean pre-procedure international normalized ratio (INR) was 1.1 and platelet count 193 × 10⁹/L. Diagnostic specimens were obtained in 32 of 36 patients (89%). Thirteen complications were encountered in 12 patients (33% of cohort), including 9 pneumothoraces (4 requiring chest tubes); 1 hemothorax, which required a chest tube; and 3 self-limited pulmonary hemorrhages. Mean and median radiation doses were as follows: fluoroscopy time 3 min and 2.4 min, dose-area product (DAP) (recorded in 31 patients) 23,402 Gy·cm² and 12,453 Gy·cm², and air kerma 88 mGy and 58 mGy.

CONCLUSION

Percutaneous lung nodule needle biopsy can be performed accurately using cone-beam CT with navigational overlay.

Transforaminal intrathecal delivery of nusinersen using cone-beam computed tomography for children with spinal muscular atrophy and extensive surgical instrumentation: early results of technical success and safety

BACKGROUND

Nusinersen, the only treatment approved by the United States Food and Drug Administration for spinal muscular atrophy (SMA), is delivered intrathecally. Many children with SMA have extensive spinal instrumentation and deformities, often precluding the use of standard approaches for gaining intrathecal access. Furthermore the anatomical distortion that often occurs with rotoscoliosis can complicate the use of fluoroscopic guidance. Compared to fluoroscopy, CT affords superior guidance for complex needle placements. This opens up alternatives to the posterior (interlaminar) technique, including transforaminal and caudal approaches.

OBJECTIVE

This study describes the early results of technical success, complications and radiation dose of intrathecal delivery of nusinersen using cone-beam CT guidance with two-axis fluoroscopic navigational overlay.

MATERIALS AND METHODS

We conducted a retrospective review of 15 consecutive nusinersen injections performed in four children with SMA and extensive spinal hardware precluding standard posterior lumbar puncture techniques. These children were treated using transforaminal thecal access employing cone-beam CT with navigational overlay. We analyzed results including technical success, complications and total fluoroscopy time.

RESULTS

All procedures were technically successful. No major complications and one minor complication were reported; the minor complication was a post-procedural neuropathic headache that was attributed to procedural positioning and was treated successfully with gabapentin. The average procedural fluoroscopy time and air kerma were 1.9 min and 55.8 mGy, respectively.

CONCLUSION

Cone-beam CT guidance with two-axis navigational overlay is a safe, effective method for gaining transforaminal intrathecal access in children with spinal abnormalities and hardware precluding the use of standard techniques.

Reduced-dose C-arm computed tomography applications at a pediatric institution

BACKGROUND

Reduced-dose C-arm computed tomography (CT) uses flat-panel detectors to acquire real-time 3-D images in the interventional radiology suite to assist with anatomical localization and procedure planning.

OBJECTIVE

To describe dose-reduction techniques for C-arm CT at a pediatric institution and to provide guidance for implementation.

MATERIALS AND METHODS

We conducted a 5-year retrospective study on procedures using an institution-specific reduced-dose protocol: 5 or 8 s Dyna Rotation, 248/396 projection images/acquisition and 0.1-0.17 μGy/projection dose at the detector with 0.3/0.6/0.9-mm copper (Cu) filtration. We categorized cases by procedure type and average patient age and calculated C-arm CT and total dose area product (DAP).

RESULTS

Two hundred twenty-two C-arm CT-guided procedures were performed with a dose-reduction protocol. The most common procedures were temporomandibular and sacroiliac joint injections (48.6%) and sclerotherapy (34.2%). C-arm CT was utilized in cases of difficult percutaneous access in less common applications such as cecostomy and gastrostomy placement, foreign body retrieval and thoracentesis. C-arm CT accounted for between 9.9% and 80.7% of the total procedural DAP.

CONCLUSION

Dose-reducing techniques can preserve image quality for intervention while reducing radiation exposure to the child. This technology has multiple applications within pediatric interventional radiology and can be considered as an adjunctive imaging tool in a variety of procedures, particularly when percutaneous access is challenging despite routine fluoroscopic or ultrasound guidance.