MR Imaging of Osteoid Osteoma: Pearls and Pitfalls

Short- and Long-Term Outcomes after Radiofrequency Ablation of Osteoid Osteomas

The aim of this study was to evaluate treatment of osteoid osteomas using bipolar radiofrequency ablation (RFA) and patients' quality of life before and after therapy. We retrospectively evaluated patients who underwent bipolar RFA of osteoid osteomas between 2001 and 2016. We assessed patients' symptoms before and after treatment (four weeks after treatment and long-term) using a questionnaire including severity and quality of pain on a 10-point scale (1 = no pain, 10 = severe pain), motion restrictions, pain-related sleep disorders, and necessary pain medication. In addition, we evaluated technical success, complications, hospitalization length, and patients' satisfaction with treatment. This study included 62 patients (43 [69.4%] males, 26.2 ± 13.2 years). Average nidus size was 5.7 ± 2.6 mm. The rate of technical success was 100%. All RFAs were performed without any complications. One patient showed a recurrence, resulting in a recurrence rate of 1.6%, which was successfully treated by another session of RFA. Average hospitalization length was 1.5 ± 0.5 days. A total of 36 patients (58.1%) participated in the questionnaire, reporting an average pain severity of 8.2 ± 1.6 before RFA compared to 3.4 ± 3.0 four weeks after and an average of 2.1 ± 2.3, 6.6 years after therapy, (both p < 0.001). After therapy, 31 (86.1%) patients had no pain. The majority of patients (n = 34, 94.4%) had reduced or absent motion restriction after therapy (p < 0.001). Patient satisfaction rate was 91.7%. In conclusion, bipolar RFA is a safe and effective treatment modality for osteoid osteomas and improves quality of life by reducing pain severity and motion restrictions.

A comparative study assessing the efficacy and safety of radiofrequency ablation versus surgical treatment for osteoid osteoma: retrospective analysis in a single institution

OBJECTIVE

We aim to evaluate the efficacy of CT-guided percutaneous radiofrequency ablation (RFA) and surgical treatment in osteoid osteoma (OO) treated at the Medical University of Graz.

MATERIALS AND METHODS

In a single-institution study, we analysed data from January 2005 to January 2021 of patients with histological/radiological diagnosis of OO. CT and MRI scans were reviewed for typical findings. Means (with SD) and medians (with IQR) were reported for normally and non-normally distributed variables. Differences between groups were assessed using chi-squared tests and t-tests.

RESULTS

One hundred nineteen patients (mean age: 21.6 ± 10.9 years; 63.9% males) with confirmed OO were retrospectively evaluated. 73 and 43 patients underwent RFA and surgery, respectively. In three cases, RFA combined with surgery was performed. Pre-intervention, 103 patients (88.8%) had undergone CT, and 101 had an MRI (87.1%). The nidus was confirmed in 82.5% of cases with CTs (85/103) and 63.4% with MRIs (64/101). The majority of nidi were located cortically (n = 96; 82.8%), most frequently in the femur (38 patients, 33.3%) with a median size of 8.0 mm (IQR: 5.0-12.0 mm). Median symptom duration before treatment was 6.0 (IQR: 4.0-13.0) months. The complication rate was 12.1% (14/116; 15.1% RFA vs. 7.0% surgery; p = 0.196). In total, 11.2% of patients had persistent symptoms after one week with clinical success rates of RFA and surgery, 86.3% and 90.7% (p = 0.647), respectively.

CONCLUSION

Compared to surgical treatment, CT-guided percutaneous RFA is a safe, minimally invasive, reliable, and efficient treatment option for OO.

CRITICAL RELEVANCE STATEMENT

This article critically assesses the diagnosis and treatment of osteoid osteoma, emphasising accurate imaging, and detailing a non-invasive option for effective management.

KEY POINTS

• This study analyses 116 cases of OO at one institution, focusing on symptom persistence, recurrence in short-term follow-up, and complications in two study groups. • Surgery showed higher, though not statistically significant, success despite comparable symptom persistence; CT displayed typical OO features more than MRI, regardless of the intramedullary, cortical and subperiosteal location as well as the site of the affected bone. • CT-guided RFA is an effective therapeutic alternative for OO compared to surgical intervention. In case of atypical OO appearance, RFA is not the first-line treatment.

The effect of radiofrequency ablation on pain score and non-steroidal painkiller use in osteoid osteoma patients

AIM

CT-guided radiofrequency ablation (RFA) is among the thermal ablative procedures and provides great benefits with a minimally invasive procedure. In this prospective study, we aimed to reveal the significance of a multidisciplinary method in reducing the recurrence and complications in osteoid osteoma patients with CT-guided RFA performed by a team of experts in the field.

MATERIALS AND METHODS

A total of consecutive 40 patients with osteoid osteoma were prospectively evaluated and treated with CT-guided RFA. Before and the post ablation the visual analog scale (VAS) and use of nonsteroidal anti-inflammatory drugs (NSAIDS) were compared.

RESULTS

Post-ablation VAS of the patients at the 1st week and 3rd month after the procedure decreased significantly (p < 0.01) compared to the pre-ablation. The frequency of NSAID use after the ablation decreased significantly (p < 0.01) compared to the pre-ablation time. The pre-procedure NSAID use of our patients included in the study was average 6.93 per week, the NSAID use in the 3rd month post-procedure controls was average 0.53 per week. Recurrence was detected in 4 of our patients, 36 patients had complete recovery.

CONCLUSION

Radiofrequency ablation is an effective treatment method in the management of osteoid osteomas. Radiofrequency ablation has low recurrence rates and provides rapid regression in patients' pain after treatment.

Sinus tarsi and sinus tarsi syndrome: An imaging review

The sinus tarsi is a funnel-shaped region at the junction of mid-foot and hind-foot which contains fat, vessels, nerves and ligaments. The ligaments help stabilise the subtalar joint and maintain the longitudinal arch of the foot. The nerve endings contain proprioceptive fibres indicating a role for the sinus tarsi in movement of the foot. Sinus tarsi syndrome is a clinical entity characterised by lateral hind-foot pain with worsening on palpation and weight-bearing, and perceived instability. It is associated with both traumatic and non-traumatic causes. Magnetic resonance imaging is the imaging modality of choice for assessment of the sinus tarsi and sinus tarsi syndrome. In this review article, we review the anatomy and various aetiologies of sinus tarsi syndrome, along with the imaging appearances.

Intra-articular Osteoid Osteoma of the Olecranon Fossa

Osteoid osteomas are benign primary bone lesions characterized by a central nidus with surrounding reactive sclerosis, classically presenting as worsening nocturnal pain relieved by non-steroidal anti-inflammatory medications (NSAIDs). These most commonly occur in intracortical bone and the diaphysis of long bones. As a rare entity, intra-articular osteoid osteomas present unusually, often resulting in a delayed or incorrect diagnosis. We present a case of an intra-articular osteoid osteoma, emphasizing the importance of MRI in aiding diagnosis in this atypical location.

Avoiding Misdiagnosis and Missed Diagnosis for Appropriately Treating Spinal Osteoid Osteomas: A Single‐Center Experience

Objectives

To analyze the causes of misdiagnosis and missed diagnosis in spinal osteoid osteoma, and to put forward solutions to improve diagnosis accuracy and treatment efficacy in patients.

Methods

We performed a retrospective cohort study on patients with spinal osteoid osteoma in Beijing Jishuitan Hospital from January 1983 to September 2019. All patients underwent surgery. The outcome measures were the extent of local pain, nocturnal pain, radicular symptoms of extremities after surgery, and reduction or disappearance of lesions on CT after surgery.

Results

Thirty‐seven patients with spinal osteoid osteoma were recruited in the study. A total of 27% were female, and the mean (SD) age at diagnosis was 21.3 (8.7) years. A total of 87.0% of patients presented with nocturnal pain, and 94.7% of patients were responsive to NSAIDS treatment. The mean (SD) time from the initial onset of symptoms to the final diagnosis was 14.7 (12.5) months. Only four of 37 (10.8%) patients were correctly diagnosed with spinal osteoid osteoma on the first visit to the local hospital. CT is associated with a higher diagnosis rate than X‐ray or MRI on the first visit. Surgical navigation was used in 88.9% of patients who underwent curettage resection, and in 10% of patients who underwent en bloc resection. A total of 37 of 37 patients (100%) reported relief of local pain and radicular symptoms of extremities after surgery, and no recurrence of tumors was found during follow‐ups.

Conclusions

Spinal CTs are recommended to be performed if osteoid osteoma is suspected based on clinical manifestation, including nocturnal pain and responsiveness to NSAIDS treatment, to avoid misdiagnosis and missed diagnosis of spinal osteoid osteoma.

[Bone and soft tissue tumours in children : Proposal for a rational diagnostic approach]

CLINICAL/METHODOLOGICAL ISSUE

Bone and soft tissue tumours are often incidental findings in children. Because they are usually benign tumours, nonspecialised radiologists generally have little experience in the diagnosis and differentiation from malignant tumours. Various imaging techniques are used in the diagnosis of skeletal tumours.

STANDARD RADIOLOGICAL METHODS

Imaging techniques used to evaluate bone and soft tissue tumours include sonography, computed tomography (CT) and magnetic resonance imaging (MRI).

METHODOLOGICAL INNOVATIONS

An algorithm to determine malignancy of bone and soft tissue tumours in children is proposed.

PERFORMANCE

By using the presented algorithms, further diagnostic procedures such as biopsies can be avoided in the majority of children with bone and soft tissue tumours. Aggressive bone lesions and unclear soft tissue tumours are guided to biopsy to confirm diagnosis.

ACHIEVEMENTS

The algorithms presented are based on the proposals of European professional societies and have been adapted by the authors for use in children and adolescents.

PRACTICAL RECOMMENDATIONS

In the clarification of soft tissue tumours, sonography is the first diagnostic tool; depending on the sonographic findings, MRI is the technique for further clarification. Biopsy confirmation of the diagnosis in unclear cases or in cases of probable malignancy should be carried out in a paediatric oncology centre.

Non-Compressive, Disabling, Cervical Radiculopathy and Neck Pain: Cave Osteoid Osteoma

Cervical radiculopathy is a common clinical condition with an annual incidence of 85/10,000. Refractory cases with positive disco-vertebral imaging findings are routinely referred to the Neurosurgeon for evaluation and treatment. In the absence of a clearcut compressive etiology, other rarer but surgically curable causes must be considered before recommending conservative management. We discuss the case of an otherwise active, healthy patient with an invalidating, refractory, relapsing nuchal pain and cervical radiculopathy. Only careful and state-of-the-art neuroimaging led to the correct diagnosis: an osteoid osteoma of the right C6 lamina was diagnosed and microsurgically resected allowing complete recovery and cure. The clinical features of these rare tumors in this unusual location are reviewed. The case is relevant for multifold reasons: it draws attention to rare conditions which can mimic radicular compression; emphasizes the need for a careful evaluation and appreciation of specific clinical symptoms and signs associated with non-compressive radiculopathies; prompts planning of a state of the art imaging workup, in order to rule out such an elusive tumor. All these measures minimize the risk of overlooking the present and other rare pathologies, sparing patients a long path of time-consuming, frustrating and cost-ineffective studies and treatment modalities.