Patients diagnosed with benign bone tumours will be relieved to know that these are not malignant, and some tumours will involute spontaneously. However, this natural history can be unpredictable, and tumours can be associated with significant pain, pathologic fracture, or potential for growth and compression of critical structures such as nerves.
Interventional approaches are increasingly being applied to this domain after multidisciplinary discussions. Two common indications that interventionists may encounter are:
Osteoid osteoma and osteoblastoma
Most often these lesions are treated due to pain. Single-session biopsy and thermal ablation has become a standard of care at many institutions. The majority of cases will be treated with general anaesthesia as instrumentation of the nidus can create significant involuntary patient movement due to pain. Utilisation patterns of radiofrequency (RF), microwave, and cryoablation, and other options such as laser ablation and high-intensity focused ultrasound will be dictated by operator preference and device availability, and local insurance coverage.
RF ablation has the benefit of a long track record in the literature and colloquial familiarity in the orthopaedic surgery and neurosurgery domains. Use of cooled RF systems may be helpful to prevent carbonisation in heavily sclerotic lesions. Cryoablation has emerged as a convenient alternative as it can provide a larger zone of ablation per probe chance to visualise the extraosseous extent of the ice ball and extrapolate the intraosseous treatment zone.
Aneurysmal bone cyst
Most often these lesions are treated due to impending pathologic fracture. Depending on the size and location of the lesion, multiple sessions and modalities may be applied to achieve osseous consolidation of the lesion. Intralesional sclerotherapy is a valuable option and can serve as a monomodal therapy, sometimes requiring multiple sessions. In cases where there is halted progression but slow osseous consolidation, augmentation with osteoconductive cements may be considered; compared to polymethylmethacrylate these biologic agents will allow natural bone ingrowth. Thermal ablation can be considered if loculations limit spread of sclerotherapy agent, with cryoablation serving a unique role as the ice-ball can be completely visualised and some of these lesions are in proximity to important nerves or open physes.
Embolization has a role in lesions that are particularly high risk for thermal ablation due to adjacent structures, have insufficient cortex to contain sclerotherapy agents, and are in surgically unfavourable locations (such as the pelvis). Embolization can be a monotherapy or enable other aforementioned therapies by allowing interval consolidation and remodelling of the cortex to contain injectable agents.
In summary, benign bone tumours serve as an opportunity to apply a broad range of interventional techniques to achieve pain relief and prevent skeletal events such as pathologic fracture.
Alan Sag is an interventional radiologist and spine specialist at Duke Interventional Radiology Clinic, Durham, USA.
