Osteoid osteoma

RF ablation has been used as an alternative method for treating certain bone tumors such as painful osteolytic metastatic lesions (Callstrom et al. 2000), osteoid osteoma (Rosenthal et al. 1992,1995,2001), and chondroblastoma (Erickson et al. 2001). 

In their series of 12 adult patients with a single painful osteolytic metastasis, Callstrom et al. (2002) showed onascale of 1 to 10,mean worst pain decreased from 8.4 to 3.1 after treatment. Osteoid osteomas are well suited to RF ablation because they are small, benign, and have finite growth. Approximately 90% of patients with osteoid osteoma are permanently cured after a single treatment. In such patients, percutaneous ablation with radiofrequency is essentially equivalent to operative excision (Rosenthal et al. 1998). 

Radiofrequency ablation in the treatment of benign osteoid osteoma causing severe pain is a well known and clinically accepted indication and has replaced open surgery due to its less invasive character and higher success rate regarding clinical symptoms (Woertler et al. 2001). 

Woertler K, Vestring T, Boettner F etal. (2001) Osteoid osteoma CT-guided percutaneous radiofrequency ablation and follow-up in 47 patients. J Vase Interv Radiol 12 717-722... 

RFA has been used for the last 30 years to treat cardiac arrhythmia (Luderitz 2003). It has been used over many years for the treatment of trigeminal neuralgia (Oturai et al. 1996) and osteoid osteomas (Rosenthal et al. 1998). 

Radiofrequency Therapy 208 The Procedure 209 Complications 210 Clinical Experience 210 Osteoid Osteoma 210 Bone Metastases 212 Conclusion 212 References 213... 

Osteoid osteoma is a benign lesion of the skeleton consisting of a central area of osteoplastic tissue (nidus) surrounded by a zone of reactive sclerotic bone (Figs. 6.4, 6.5, 6.6). The main symptom is pain, which is most severe at night and can often be relieved by aspirin and other nonsteroidal antiinflammatory drugs (Pinto et al. 2002). Most of... 

Fig. 6.4. A 17-year-old female patient with osteoid osteoma in the left tibia. Note the nidus (arrow)...

Fig. 6.8. A 19-year-old male patient with osteoid osteoma in the right femur. Percutaneous and CT-guided approach. Note the exact positioning of the radiofrequency electrode in the center of the nidus...

Table 6.1. Literature review. Different studies treating osteoid osteoma using radiofrequency ablation...

AronowS (1960) The use ofradio-frequencypower in making lesions in the brain. J Neurosurg 17 431-438 Barei DP, Moreau G, Scarborough MT, Neel MD (2000) Radiofrequency Ablation of Osteoid Osteoma. Clin Orthop Relat Res 373 115-124... 

Ramseier LEDS, Exner GU (2006) Osteoid osteoma CT guided drilling and radiofrequency ablation. Orthopade... 

Venbrux AC, Montague BJ, Murphy KP, Bobonis LA, Washington SB, Soltes AP, Frassica FJ (2003) Image-guided percutaneous radiofrequency ablation for osteoid osteomas. J Vase Interv Radiol 14(3) 375-380 Woertler KVT, Boettner F, Winkelmann W, Heindel W, Lindner N (2001) Osteoid osteoma CT-guided percutaneous radiofrequency ablation and follow-up in 47 patients. J Vase Interv Radiol 12 717-722... 

Thermal Ablation in Osteoid Osteomas Results of Thermal Ablation in Osteoid Osteomas 246 Thermal Ablation in Malignant Bone Tumours 246 Results of Thermal Ablation in Malignant Bone Tumours 247 Complications 248 Summary 249 References 250... 

The typical clinical signs in bone tumours are pain, destruction and destabilization, immobilization, neurologic deficits, and finally functional impairment. Primary malignant bone tumours are a rare entity, accounting for about 0.2% of all malignancies. Also benign primary bone tumours are in total rare and mostly asymptomatic. The most common symptomatic benign bone tumour is osteoid osteoma with an incidence of 1 2000. 

In this setting, thermal ablation will be mainly a symptomatic, supportive (palliative) therapy, which can also be applied in conjunction with other therapies such as resection, radiotherapy or chemotherapy. In contrast to the treatment of malignant tumours, local thermal ablation is considered the method of choice in treatment of symptomatic benign bone tumours such as osteoid osteomas. 

Osteoid osteoma is a benign lesion of unknown origin. Typically, the lesion is formed by a central, vascularized nidus surrounded by a reactive sclerosis with a diameter of less than 2 cm, in contrast to the larger osteoblastoma. Because of the central nidus, a vascular malformation is discussed as being the origin of these lesions. Most of the tumours occur in the first three decades of life, with a male predominance (maleifemale = 2 1). Osteoid osteomas can be found in any bone of the body however, the spine is the preferred localization, where 50% of all osteoid osteomas occur in the lumbar spine, and 75% of the tumours in the pedicles of the vertebrae. Other typical localizations are femur, radius, knee and ankle. 

The typical radiographic appearance of an osteoid osteoma together with the clinical symptoms and a positive aspirin test (i.e. pain relieO confirms the diagnosis (Klein and Shankman 1992 Shankman et al. 1997 Pinto et al. 2002) (Figs. 9.1a, 9.2a). 

In general, osteoid osteoma is cured when the nidus is destroyed. This can be achieved by complete removal of the lesion or by just destroying the nidus, which is thought responsible for the symptoms. 

In surgery - which used to be considered the treatment of choice - the osteoid osteoma is removed en bloc since the enostal nidus is, in general, not visible. In open surgery the hyperscle-... 

To avoid secondary harm to structures near to an osteoid osteoma, special attention must be paid... 

Fig. 9.1. a An 11-year-old girl with an osteoid osteoma of the left pedicle of the sixth vertebra of the thoracic spine. Note the partially sclerosed nidus together with the dense surrounding hyperostosis, b The dense cortical lamella was perforated by a biopsy cannula with a crown cut. c Subsequently, a radiofrequency single electrode with an active tip of 1 cm was placed into the nidus. To protect adjacent myelin structures a 21-gauge needle was placed into the epidural space for saline flushing... 

Fig. 9.2. a Osteoid osteoma of the femoral shaft in a 32-year-old male patient with typical nocturnal dominant pain attacks over the last 12 months. There was moderate to minor pain relief after salicylate intake. Note the reactive sclerosis completely surrounding the soft-tissue dense nidus, b The dense sclerosis surrounding the nidus could not be passed directly therefore, an access route from the opposite site was chosen. Note that the tip of the electromechanical drill is shown slightly beside the nidus arrow). c The radiofrequency electrode was positioned through the drilled cortical hole eccentrically next the nidus. Due to the penetration depth of about 10 mm of the radiofrequency around the needle tip the nidus is still within the range of the ablation zone. This osteoid osteoma could be successfully ablated with 7 W over 9 min... 

Table 9.1. Primary and secondary success rate of thermoablation in osteoid osteoma...

The excellent results achieved using thermal ablation to treat osteoid osteomas mean that it must be considered to be the method of first choice, superior to surgical resection. 

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