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Department of Radiology
Seth G.S. Medical College and K.E.M. Hospital, Mumbai , India
Interventional Case Record
Interventional Case Record
Radiofrequency Thermal Ablation (RFTA) of Osteoid Osteoma In the Talus
Radiofrequency Thermal Ablation (RFTA) of Osteoid Osteoma In the Talus
Contributed by : Nikhil Parvatkar
Contributed by : Nikhil Parvatkar
Introduction:
Introduction:
Osteoid osteomas are benign bone tumours commonly found in the cortex of long bones; but can occasionally occur in atypical locations like the posterior elements of the spine, or peripheral bones like phalanges and tarsals. They typically present in younger males and are characterized by lesions with a vascularized nidus surrounded by sclerotic bone. Plain radiographs can may miss these findings; therefore, requiring CT or MRI. Lesions often lead to a significant inflammatory response resulting in an impaired range of motion and nocturnal pain. Conservative management with non-steroidal anti-inflammatory medications is considered the first-line therapy, with failure to respond being an indication for surgical intervention. Surgical treatment traditionally consisted of en bloc resection but has been replaced by CT-guided radio-frequency ablation (RFA) when conservative management has failed. (1)
Osteoid osteomas are benign bone tumours commonly found in the cortex of long bones; but can occasionally occur in atypical locations like the posterior elements of the spine, or peripheral bones like phalanges and tarsals. They typically present in younger males and are characterized by lesions with a vascularized nidus surrounded by sclerotic bone. Plain radiographs can may miss these findings; therefore, requiring CT or MRI. Lesions often lead to a significant inflammatory response resulting in an impaired range of motion and nocturnal pain. Conservative management with non-steroidal anti-inflammatory medications is considered the first-line therapy, with failure to respond being an indication for surgical intervention. Surgical treatment traditionally consisted of en bloc resection but has been replaced by CT-guided radio-frequency ablation (RFA) when conservative management has failed. (1)
Case presentation:
Case presentation:
A 14 year old boy presented with pain in the left ankle on and off since one year. The pain was predominantly nocturnal and after strenuous activities like running. There was no history of trauma or inciting event. He had seen several specialists prior to presenting to our institution and had been diagnosed with a stress reaction within the talus. On examination there was no swelling in the left foor or ankle. Tenderness was present over the antero lateral aspect over talus. On Visual Analog scale (VAS) the patient reported pain as 8/10.
A 14 year old boy presented with pain in the left ankle on and off since one year. The pain was predominantly nocturnal and after strenuous activities like running. There was no history of trauma or inciting event. He had seen several specialists prior to presenting to our institution and had been diagnosed with a stress reaction within the talus. On examination there was no swelling in the left foor or ankle. Tenderness was present over the antero lateral aspect over talus. On Visual Analog scale (VAS) the patient reported pain as 8/10.
Physical therapy improved the mobility and strength of ankle but did not alleviate his pain. He took oral NSAIDs before bedtime, which gave him excellent relief and allowed him to sleep.
Physical therapy improved the mobility and strength of ankle but did not alleviate his pain. He took oral NSAIDs before bedtime, which gave him excellent relief and allowed him to sleep.
Radiographs of the left ankle and foot (Fig 1, Fig 2) were interpreted as 'normal'.
Radiographs of the left ankle and foot (Fig 1, Fig 2) were interpreted as 'normal'.
FIG 1, FIG 2 : AP and Lateral projections of xray of the left ankle are normal.
MDCT scan of the left ankle showed a small round lesion (1.5 x 1.5 cm) in the lateral talar dome with central lucency and surrounding sclerosis with a central hyperdense nidus. The rest of the tarsal bones and metatarsals were normal. The ankle joint was normal (Fig 3, Fig 4)
MDCT scan of the left ankle showed a small round lesion (1.5 x 1.5 cm) in the lateral talar dome with central lucency and surrounding sclerosis with a central hyperdense nidus. The rest of the tarsal bones and metatarsals were normal. The ankle joint was normal (Fig 3, Fig 4)
FIG 3 , FIG 4 : Axial CT scans showing lytic lesion in the lateral talar dome with central nidus and surrounding sclerotic margin.
MRI demonstrated a focally STIR hyperintense lesion in the talar dome with central nidus and surrounding rim of low signal due to sclerosis. Diffuse bone oedema was seen in the surrounding talus bone. (Fig 5, Fig 6)
MRI demonstrated a focally STIR hyperintense lesion in the talar dome with central nidus and surrounding rim of low signal due to sclerosis. Diffuse bone oedema was seen in the surrounding talus bone. (Fig 5, Fig 6)
FIG 5 : Ankle MRI STIR sequence showing a focally STIR hyperintense lesion in the talar dome with central nidus and surrounding rim of low signal due to sclerosis.
FIG 6 : TI weighted image ankle MRI showing the lesion in the lateral talar dome.
A diagnosis of osteoid osteoma of the talus was made; the patient was referred for CT guided radiofrequency ablation (RFA)
A diagnosis of osteoid osteoma of the talus was made; the patient was referred for CT guided radiofrequency ablation (RFA)
Interventional technique:
Interventional technique:
The procedure was performed under CT guidance. After obtaining informed consent, spinal anaesthesia was administered. The patient was supine on the CT table with feet first. Grounding pads were applied to both thighs and legs.
The procedure was performed under CT guidance. After obtaining informed consent, spinal anaesthesia was administered. The patient was supine on the CT table with feet first. Grounding pads were applied to both thighs and legs.
After placing markers on the anterior and lateral aspect of the ankle joint, an initial scan was acquired to plan the entry point of the RFA probe. An anterolateral approach was decided to avoid the anterior tibial artery and the surrounding neurovascular bundle.
After placing markers on the anterior and lateral aspect of the ankle joint, an initial scan was acquired to plan the entry point of the RFA probe. An anterolateral approach was decided to avoid the anterior tibial artery and the surrounding neurovascular bundle.
On marking the skin entry site, adequate local anaesthesia was administered from the skin upto the bony cortex of the talus with a 20 G spinal needle. A scan was repeated with the spinal needle in place to confirm the trajectory.
On marking the skin entry site, adequate local anaesthesia was administered from the skin upto the bony cortex of the talus with a 20 G spinal needle. A scan was repeated with the spinal needle in place to confirm the trajectory.
Once the trajectory was confirmed, a 13 G x 10 cm Cook Osteosite Bone Biopsy needle was advanced up to the cortex and advanced into the nidus of the lesion. Multiple scans were taken to confirm the trajectory and the tip of the needle. (Fig 7).
Once the trajectory was confirmed, a 13 G x 10 cm Cook Osteosite Bone Biopsy needle was advanced up to the cortex and advanced into the nidus of the lesion. Multiple scans were taken to confirm the trajectory and the tip of the needle. (Fig 7).
RFA Single Needle Electrode of 16.5 G x 18 cm (Soloist – Boston Scientific), with an active tip of 1 cm was introduced into the lesion. The bone biopsy needle was then withdrawn just by 1 cm and a check scan performed to confirm the position. (FIG 8, 9, 10).
RFA Single Needle Electrode of 16.5 G x 18 cm (Soloist – Boston Scientific), with an active tip of 1 cm was introduced into the lesion. The bone biopsy needle was then withdrawn just by 1 cm and a check scan performed to confirm the position. (FIG 8, 9, 10).
Radiofrequency was then performed for 2 cycles – 15 Watts for 13 mins and 10 Watts for 4 mins with continuous impedance feedback. The impedance prior to ablation was 40 ohms which increased to 220 ohms post ablation suggesting cellular destruction and completion of thermal ablation.
Radiofrequency was then performed for 2 cycles – 15 Watts for 13 mins and 10 Watts for 4 mins with continuous impedance feedback. The impedance prior to ablation was 40 ohms which increased to 220 ohms post ablation suggesting cellular destruction and completion of thermal ablation.
FIG 7 : Lesion targeted using the Bone Biopsy needle.
FIG 8 : Assembly of the RFA Probe inserted via the cannula of the bone biopsy needle.
FIG 9, FIG 10: Tip of the RFA probe at the centre of the lesion, and the withdrawn bone biopsy needle.
Post ablation the RFA probe and the bone biopsy needle were removed and compression bandage applied. The procedure was uneventful and patient tolerated the procedure well.
Post ablation the RFA probe and the bone biopsy needle were removed and compression bandage applied. The procedure was uneventful and patient tolerated the procedure well.
After two weeks of the procedure, the patient reported with complete resolution of night pains, and did not need any NSAIDs. On Visual Analog scale (VAS) he now reported a pain scale of 0/10.
After two weeks of the procedure, the patient reported with complete resolution of night pains, and did not need any NSAIDs. On Visual Analog scale (VAS) he now reported a pain scale of 0/10.
FIG 11 : Pathophysiology of osteoid osteoma
Discussion:
Discussion:
An osteoid osteoma is a benign osteogenic bone tumor, which comprises 10–14% of benign bone tumors. It mainly affects individuals in the second or third decade of life with a definite male predilection. The most common site is the meta-diaphyseal location of the femur and tibia (50%). Less common sites include the spine (10%), hands, and feet. (2) Albeit small in size (< 2 cm), it classically presents with prostaglandin-mediated intense nocturnal pain relieved by nonsteroidal anti-inflammatory drugs. For several years, surgical en-bloc resection was considered the treatment of choice for osteoid osteomas. However, surgical excision is invasive with complications such as post-surgical fracture or infections. Hence, in the past decade, it has been supplanted by minimally invasive techniques such as radiofrequency ablation, laser ablation, cryoablation, and microwave ablation. (3)
An osteoid osteoma is a benign osteogenic bone tumor, which comprises 10–14% of benign bone tumors. It mainly affects individuals in the second or third decade of life with a definite male predilection. The most common site is the meta-diaphyseal location of the femur and tibia (50%). Less common sites include the spine (10%), hands, and feet. (2) Albeit small in size (< 2 cm), it classically presents with prostaglandin-mediated intense nocturnal pain relieved by nonsteroidal anti-inflammatory drugs. For several years, surgical en-bloc resection was considered the treatment of choice for osteoid osteomas. However, surgical excision is invasive with complications such as post-surgical fracture or infections. Hence, in the past decade, it has been supplanted by minimally invasive techniques such as radiofrequency ablation, laser ablation, cryoablation, and microwave ablation. (3)
The etiology of osteoid osteomas remains a subject of debate. Some consider osteoid osteomas to be benign neoplasm. Another school of thought considers them to represent a healing process secondary to trauma or inflammation. (4) In fact, a history of antecedent trauma can be elicited in up to a third of patients with osteoid osteomas. It has been demonstrated that prostaglandin levels are increased 100 to 1000 times more in osteoid osteomas compared to normal bone. These prostaglandins cause stimulation of nociceptive nerve fibres within the nidus by vasodilatation and increased blood flow as well as by bradykinin mediated pathway resulting in intense localized pain. (5) (FIG 11)
The etiology of osteoid osteomas remains a subject of debate. Some consider osteoid osteomas to be benign neoplasm. Another school of thought considers them to represent a healing process secondary to trauma or inflammation. (4) In fact, a history of antecedent trauma can be elicited in up to a third of patients with osteoid osteomas. It has been demonstrated that prostaglandin levels are increased 100 to 1000 times more in osteoid osteomas compared to normal bone. These prostaglandins cause stimulation of nociceptive nerve fibres within the nidus by vasodilatation and increased blood flow as well as by bradykinin mediated pathway resulting in intense localized pain. (5) (FIG 11)
Osteoid osteomas have been previously reported within the talus by several groups [6-8]. Findings within these reports are consistent with our own, including populations of younger patients with spontaneous onset of ankle pain that is temporarily relieved with anti-inflammatories, but ultimately required intervention to remove the nidus and achieve long-term symptom relief.
Osteoid osteomas have been previously reported within the talus by several groups [6-8]. Findings within these reports are consistent with our own, including populations of younger patients with spontaneous onset of ankle pain that is temporarily relieved with anti-inflammatories, but ultimately required intervention to remove the nidus and achieve long-term symptom relief.
Singh et al. (2) have extensively reported multiple cases of RFA ablations in osteoid osteomas in atypical locations with an approach to each location and a detailed preoperative and intraoperative checklist, and various techniques for safe trajectory to avoid the neurovascular bundles.
Singh et al. (2) have extensively reported multiple cases of RFA ablations in osteoid osteomas in atypical locations with an approach to each location and a detailed preoperative and intraoperative checklist, and various techniques for safe trajectory to avoid the neurovascular bundles.
When performing CT-guided radiofrequency ablation (RFA) for osteoid osteomas in atypical sites, particularly those in proximity to joints, a meticulous and individualized procedural approach is essential. Needle trajectory must be planned carefully to avoid traversing joint cartilage or neurovascular structures, and accurate identification of the shortest safe path to the nidus is critical. Ablation parameters must be carefully adjusted to achieve complete coagulative necrosis while minimizing thermal injury to adjacent tissues. (9)
When performing CT-guided radiofrequency ablation (RFA) for osteoid osteomas in atypical sites, particularly those in proximity to joints, a meticulous and individualized procedural approach is essential. Needle trajectory must be planned carefully to avoid traversing joint cartilage or neurovascular structures, and accurate identification of the shortest safe path to the nidus is critical. Ablation parameters must be carefully adjusted to achieve complete coagulative necrosis while minimizing thermal injury to adjacent tissues. (9)
CT-guided radiofrequency thermal ablation (RFTA) has been proven to be an effective and safe treatment option for osteoid osteomas ( in typical locations. A safety margin of approximately 1 cm between the RF probe and any critical adjacent structures is generally recommended. However, for OOs in atypical locations, maintaining this margin may not always be feasible; therefore, additional techniques and specific precautions, including careful patient positioning, may be necessary.
CT-guided radiofrequency thermal ablation (RFTA) has been proven to be an effective and safe treatment option for osteoid osteomas ( in typical locations. A safety margin of approximately 1 cm between the RF probe and any critical adjacent structures is generally recommended. However, for OOs in atypical locations, maintaining this margin may not always be feasible; therefore, additional techniques and specific precautions, including careful patient positioning, may be necessary.
References
References
1. Wishman MD, Henry J, Rider C, Sofka C, Yoon E, Elliott A. Osteoid Osteomas of the Talus: A Case Report of Four Patients. Cureus. 2023 Jun 22;15(6):e40798. doi: 10.7759/cureus.40798. PMID: 37485164; PMCID: PMC10362808.
1. Wishman MD, Henry J, Rider C, Sofka C, Yoon E, Elliott A. Osteoid Osteomas of the Talus: A Case Report of Four Patients. Cureus. 2023 Jun 22;15(6):e40798. doi: 10.7759/cureus.40798. PMID: 37485164; PMCID: PMC10362808.
2. Singh DK, Kumar N, Rustagi A, Jalan D, Krishna LG, Sharma A. Percutaneous CT-guided radiofrequency ablation of osteoid osteoma: Potential Pitfalls and complications and how to avoid them. J Clin Orthop Trauma. 2022 Apr 16;28:101869. doi: 10.1016/j.jcot.2022.101869. PMID: 35494487; PMCID: PMC9043674.
2. Singh DK, Kumar N, Rustagi A, Jalan D, Krishna LG, Sharma A. Percutaneous CT-guided radiofrequency ablation of osteoid osteoma: Potential Pitfalls and complications and how to avoid them. J Clin Orthop Trauma. 2022 Apr 16;28:101869. doi: 10.1016/j.jcot.2022.101869. PMID: 35494487; PMCID: PMC9043674.
3. Tepelenis K., Skandalakis G.P., Papathanakos G., et al. Osteoid osteoma: an updated review of epidemiology, pathogenesis, clinical presentation, radiological features, and treatment option. In Vivo. 2021 Jul-Aug;35(4):1929–1938. doi: 10.21873/invivo.12459.
3. Tepelenis K., Skandalakis G.P., Papathanakos G., et al. Osteoid osteoma: an updated review of epidemiology, pathogenesis, clinical presentation, radiological features, and treatment option. In Vivo. 2021 Jul-Aug;35(4):1929–1938. doi: 10.21873/invivo.12459.
4. Jordan R.W., Koç T., Chapman A.W., Taylor H.P. Osteoid osteoma of the foot and ankle--A systematic review. Foot Ankle Surg. 2015 Dec;21(4):228–234. doi: 10.1016/j.fas.2015.04.005.
4. Jordan R.W., Koç T., Chapman A.W., Taylor H.P. Osteoid osteoma of the foot and ankle--A systematic review. Foot Ankle Surg. 2015 Dec;21(4):228–234. doi: 10.1016/j.fas.2015.04.005.
5. Laurence N., Epelman M., Markowitz R.I., Jaimes C., Jaramillo D., Chauvin N.A. Osteoid osteomas: a pain in the night diagnosis. Pediatr Radiol. 2012 Dec;42(12):1490–1501. doi: 10.1007/s00247-012-2495-y. ; quiz 1540-2.
5. Laurence N., Epelman M., Markowitz R.I., Jaimes C., Jaramillo D., Chauvin N.A. Osteoid osteomas: a pain in the night diagnosis. Pediatr Radiol. 2012 Dec;42(12):1490–1501. doi: 10.1007/s00247-012-2495-y. ; quiz 1540-2.
6. Diagnosis failure led to the recurrence of an intra-articular osteoid osteoma at the talus neck after arthroscopic excision. Dubuc JE, Docquier PL, Schubert T, Galant C, Malghem J. Foot Ankle Surg. 2014;20:0–2. doi: 10.1016/j.fas.2014.02.007.
6. Diagnosis failure led to the recurrence of an intra-articular osteoid osteoma at the talus neck after arthroscopic excision. Dubuc JE, Docquier PL, Schubert T, Galant C, Malghem J. Foot Ankle Surg. 2014;20:0–2. doi: 10.1016/j.fas.2014.02.007.
7. A misdiagnosed case of osteoid osteoma of the talus: a case report and literature review. He H, Xu H, Lu H, Dang Y, Huang W, Zhang Q. BMC Musculoskelet Disord. 2017;18:35. doi: 10.1186/s12891-017-1413-8.
7. A misdiagnosed case of osteoid osteoma of the talus: a case report and literature review. He H, Xu H, Lu H, Dang Y, Huang W, Zhang Q. BMC Musculoskelet Disord. 2017;18:35. doi: 10.1186/s12891-017-1413-8.
8. Osteoid osteoma of the talus presenting as posterior ankle impingement: case reports. Winters KN, Jowett AJ, Taylor H. Foot Ankle Int. 2011;32:1095–1097. doi: 10.3113/FAI.2011.1095.
8. Osteoid osteoma of the talus presenting as posterior ankle impingement: case reports. Winters KN, Jowett AJ, Taylor H. Foot Ankle Int. 2011;32:1095–1097. doi: 10.3113/FAI.2011.1095.
9. Desi, G.L., Arabia, F., Antonello, A. et al. Radiofrequency thermal ablation (RFTA) of osteoid osteoma in atypical/challenging locations: a joint experience from two referral centers. J Med Imaging Intervent Radiol 12, 28 (2025). https://doi.org/10.1007/s44326-025-00071-0
9. Desi, G.L., Arabia, F., Antonello, A. et al. Radiofrequency thermal ablation (RFTA) of osteoid osteoma in atypical/challenging locations: a joint experience from two referral centers. J Med Imaging Intervent Radiol 12, 28 (2025). https://doi.org/10.1007/s44326-025-00071-0
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