Paediatric musculoskeletal interventional radiology

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

RATIONALE AND OBJECTIVES

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Impact of radiation dose reduction and iterative image reconstruction on CT-guided spine biopsies

This study aimed to systematically evaluate the impact of dose reduction on image quality and confidence for intervention planning and guidance regarding computed tomography (CT)-based intervertebral disc and vertebral body biopsies. We retrospectively analyzed 96 patients who underwent multi-detector CT (MDCT) acquired for the purpose of biopsies, which were either derived from scanning with standard dose (SD) or low dose (LD; using tube current reduction). The SD cases were matched to LD cases considering sex, age, level of biopsy, presence of spinal instrumentation, and body diameter. All images for planning (reconstruction: "IMR1") and periprocedural guidance (reconstruction: "iDose4") were evaluated by two readers (R1 and R2) using Likert scales. Image noise was measured using attenuation values of paraspinal muscle tissue. The dose length product (DLP) was statistically significantly lower for LD scans regarding the planning scans (SD: 13.8 ± 8.2 mGy*cm, LD: 8.1 ± 4.4 mGy*cm, p < 0.01) and the interventional guidance scans (SD: 43.0 ± 48.8 mGy*cm, LD: 18.4 ± 7.3 mGy*cm, p < 0.01). Image quality, contrast, determination of the target structure, and confidence for planning or intervention guidance were rated good to perfect for SD and LD scans, showing no statistically significant differences between SD and LD scans (p > 0.05). Image noise was similar between SD and LD scans performed for planning of the interventional procedures (SD: 14.62 ± 2.83 HU vs. LD: 15.45 ± 3.22 HU, p = 0.24). Use of a LD protocol for MDCT-guided biopsies along the spine is a practical alternative, maintaining overall image quality and confidence. Increasing availability of model-based iterative reconstruction in clinical routine may facilitate further radiation dose reductions.

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.

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

BACKGROUND

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

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.