Percutaneous radiofrequency ablation of osteoid osteoma

Case report: osteoid osteoma of the C2 pedicle: surgical technique using a navigation system

An osteoid osteoma of the cervical spinal pedicle is rare and carries a high surgical risk because of the close anatomic relationship to the spinal cord, nerve root, and vertebral artery. We report the case of a 12-year-old girl with an osteoid osteoma of the C2 pedicle. Computed tomograms showed an oval nidus and marked sclerosis around this lesion at the right C2 pedicle. There also was expansion of the medial and inferior cortical bone of the C2 pedicle. After failure of nonoperative treatment, we planned surgery. Owing to concerns regarding thermal damage to the spinal cord, nerve root, and/or vertebral artery using computed tomography (CT)-guided radiofrequency ablation, we curetted the nidus using a navigation system. Twenty-eight months after surgery, her pain was relieved with no limitation of cervical movement and there has been no evidence of recurrence. Navigation allowed safe curettage of the nidus through a small hole while maintaining spinal stability.

Percutaneous core excision and radiofrequency thermo-coagulation for the ablation of osteoid osteoma of the spine

Percutaneous radiofrequency ablation is the treatment of choice for osteoid osteoma of the appendicular skeleton. However, difficulties in localizing the lesion in the spine and its proximity to neural elements have yet to make it the prevalent treatment for spine. This study assesses the safety and effectiveness of two percutaneous techniques for ablating osteoid osteoma of the spine. Seven patients were treated between 1998 and 2005. Four patients underwent percutaneous radiofrequency coagulation. The lesions were located at the articular processes of L3 and L4, the lamina of L3 and in the head of the 11th rib. Three patients with lesions in close proximity to neural structures (pedicle of T9, the posterolateral inferior aspect of L3 vertebral body and the inferior articular process of C5) were subjected to percutaneous core excision. Mean follow-up was 4.2 +/- 1.6 years. Three out of four patients who underwent radiofrequency ablation had an immediate and sustained response. One patient with a lesion in the head of the rib failed to respond. The three patients in the group of pecutaneous core excisional biopsy demonstrated immediate relief of pain. However, one patient experienced relapse of symptoms 6 months after transpedicular core excision. CT scan suggested partial targeting of the lesion that corroborated with histologic examination revealing only reactive tissue. Subsequent percutaneous core excision was successful. Therefore, the overall success rate was 85.7%. Mean VAS improved dramatically from 9 +/- 1 to 2 +/- 1 after surgery (P < 0.05). No neurological or other complications were encountered. This study indicates that radiofrequency ablation of spinal osteoid osteomas is safe and reasonably effective when an intact cortical shell separates the nidus from the neural elements. Percutaneous core excision can obviate the risk of thermal damage for lesions located in close proximity to the neural elements. Effectiveness of treatment can also be evaluated by CT scan and histological examination. Difficulties in targeting the nidus can lead to treatment failure. The minimal morbidity and the effectiveness of these minimally invasive procedures make them a valid alternative in the treatment of spinal osteoid osteoma.

Osteoid osteoma: diagnosis and treatment

Treatment of small but painful osteoid osteomas was traditionally based on either prolonged medication or resection. In the era of rapidly evolving minimally invasive techniques, reluctance has been posed against surgical interventions mostly due to their relatively high rates of recurrence, complications, or persistent pain. Nonetheless, incomplete pain control and intolerance to anti-inflammatory drugs unfavorably affect prognosis. The objective of this article is to explore the nature and clinical presentation of osteoid osteomas, discuss their imaging and histological features, review available data regarding surgical and percutaneous methods for addressing these lesions and comment on their feasibility, safety, and efficacy.

Osteoid osteoma of the spine: CT-guided monopolar radiofrequency ablation

CT-guided percutaneous radiofrequency ablation and laser photocoagulation have become the methods of choice for the treatment of all osteoid osteomas except those in contact with neural structures. We report 10 patients with spinal osteoid osteoma adjacent to the neural elements treated with 12 sessions of CT-guided monopolar radiofrequency ablation. The size range of the lesion was 3-14 mm (mean, 7.5 mm) and the distance between the nidus and the adjacent spinal cord or nerve root was 2-12 mm (mean, 5 mm). No intact cortex between the tumor and the spinal cord or nerve roots constituted an exclusion criterion because of a higher risk of undesirable neurotoxic effects. Patients were under general anesthesia. After location of the lesion, a 11G-bone biopsy was introduced into the nidus. The radiofrequency electrode was inserted through the biopsy needle and heated at 90 degrees C for 4 min. Primary success was obtained in eight patients. At follow-up (mean, 19.5 months; range, 6-24 months), pain persisted in two patients after 2 months. Both of them were re-treated. All patients are currently pain-free and complications were not detected. In our opinion, radiofrequency ablation can also be considered the treatment of choice for spinal osteoid osteoma.

CT fluoroscopy-guided postmyelographic transthecal radiofrequency ablation of a posterior vertebral body osteoid osteoma

The present case report describes a unique case of radiofrequency (RF) ablation of an osteoid osteoma in the inferoposterior paramedian region of the L5 vertebral body. After computed tomographic (CT) myelography, CT fluoroscopy was used to guide the transthecal approach of the RF ablation procedure.

[Osteoid osteomas of the fingers: an atypical localization? Two case reports and a review of the literature]

Osteoid osteomas are painful bone tumors that usually occur in childhood or adolescence. Despite the small size of the bony lesions osteoid osteomas can cause persistent pain. Pathogenesis has not been completely understood. Remission usually occurs within several months to years. Therefore surgical therapy is not indicated in all cases. Nevertheless, as a result of reduced quality of life due to pain, sufficient analgesic/antiinflammatory therapy needs to be provided. We report on two male patients, aged 10 and 14 years, who presented with arthritis of the finger joints. As a result of both patients' histories, and following radiographic imaging and magnetic resonance imaging, a diagnosis of osteoid osteoma was made. Remission could be achieved in both patients following treatment with nonsteroidal antiinflammatory drugs (NSAIDs).In addition to the typical sites at the long bones of the lower extremity, osteoid osteomas can also localize to other sites such as fingers. In the case of definitive diagnosis and under close follow-up, medical treatment with NSAIDs is an alternative to surgical strategies. The operative risk should be weighed against the risk of long-term treatment with NSAIDs.

Palliative care in orthopaedic surgical oncology

Hundreds of thousands of Americans are affected every year by skeletal complications of oncologic disease. Recent developments in medical oncology, radiation oncology and radiology, particularly with respect to the use of bisphosphonate medication and radiofrequency techniques, have served to greatly lessen the morbidity associated with metastatic skeletal disease. Similarly, there has been significant advancement in the field of orthopaedic oncology in the areas of internal fixation, endoprosthetic implant design, and minimally invasive kyphoplasty technology. Given the palliative intent of intervention in this patient population, the goal of treatment of skeletal metastases must be optimization of limb function and ultimately, quality of life.

Computed-tomography-guided percutaneous radiofrequency thermoablation for the treatment of osteoid osteoma-2 to 5 years follow-up

The purpose of this study is to evaluate the efficacy of the computed tomography (CT)-guided percutaneous radiofrequency thermoablation (PRT) method with a minimum of 2 years follow-up. Twenty-eight patients who were followed for more than 2 years among 35 patients who underwent CT-guided PRT between April 1999 and May 2005 were included in this study. The mean age was 24.5 years (range 7-55 years) and the mean follow-up period was 40.1 months (range 24-66 months). With a radiofrequency electrode, the lesion was heated to 80 degrees C or 90 degrees C for 6.5 mins (range 3-9 mins). Clinical success was assessed at the out-patient clinic by symptoms and radiographs. Twenty-six patients (90%) experienced a total loss of symptoms and additional PRT also relieved the ongoing symptoms in all of the recurrent patients. PRT appears to be a safe and effective method for treating osteoid osteoma and is also effective in recurrent cases. This treatment modality is a minimally invasive procedure and is a good alternative to open surgical treatment.

Osteoid osteoma of the cervical spine: surgical treatment or percutaneous radiofrequency coagulation?

Osteoid osteoma (OO) of the cervical spine is frequently located close to the vertebral artery, spinal cord, or nerve roots and complete surgical excision is sometimes difficult by a limited approach and more extended surgery can require spinal fusion. Percutaneous radiofrequency coagulation (PRC) has demonstrated efficacy in the treatment of OO of the pelvis and limbs however, its role in the cervical spine is still nuclear. The Authors present a series of nine cases of OO of the cervical spine, six treated with surgical excision and three with PRC. No neurological or vascular complications occurred in both series. One case of the surgical series had only partial relief of persistent pain for 1 year due to incomplete excision, but is doing well 4 years after surgery. All the other surgical cases had complete relief of symptoms immediately after surgery and are symptom-free 3-10 years later. Two cases of PRC had complete relief of symptoms 24-48 h after surgery and are symptom-free 2 and 3 years later. One case of recurrent OO after surgery and treated with PRC with a reduced dose improved only, and still requires anti-inflammatory drugs 2 years after the procedure. Our still limited experience suggests that PRC can be safely performed in local anaesthesia with the patient awake, enabling to check for signs and symptoms of possible neurological injury. PRC can substitute extensive posterior approaches and reconstructions for OO of the posterior arch and joint pillar.

Radiofrequency ablation of osteoid osteoma with cooled probes and impedance-control energy delivery

OBJECTIVE

Our objective was to evaluate the efficacy of percutaneous radiofrequency ablation of osteoid osteoma with cooled radiofrequency probes and impedance control energy delivery from a 200-W generator. We also compared the outcome to published data for therapy with a 5-mm noncooled probe and temperature-controlled short-duration therapy protocols.

SUBJECTS AND METHODS

Radiofrequency ablation was performed on 11 patients with a clinical and radiologic diagnosis of osteoid osteoma. A cooled radiofrequency probe was introduced into the lesion under CT guidance. Twelve minutes of radiofrequency energy was delivered from a 200-W generator under impedance control. Postprocedural pain, function, and satisfaction were evaluated by means of an interview and questionnaire.

RESULTS

All procedures were technically successful. No serious complication occurred. Postoperative pain was scored at a mean of 6.9 +/- 3.06 (95% confidence interval) on a numeric rating scale. Postoperative pain was rated as similar to night pain. By 1 week after therapy, all patients had resolution of pain and returned to normal activity. There was no recurrence during the follow-up period (range, 6-27 months; mean, 14.4 months). Patients rated their satisfaction as high.

CONCLUSION

Radiofrequency ablation of osteoid osteoma with a high-energy delivery technique is safe and has a high success rate. When compared with patients in a published series using 5-mm probes and manual energy control from lower-output generators, our cohort showed increased postoperative pain scores and an increased interval to symptom resolution.

Percutaneous osteoid osteoma treatment with combination of radiofrequency and alcohol ablation

AIM

To assess the efficacy of percutaneous osteoid osteoma treatment using a combination of radiofrequency ablation (RFA) and alcohol ablation with regard to technical and long-term clinical success.

MATERIALS AND METHODS

From December 2001 to November 2004, RFA and subsequent alcohol ablation was performed on 54 patients with osteoid osteoma, diagnosed clinically using radiography, computed tomography (CT) and symptoms. Under general anaesthesia, treatment was performed via percutaneous access under thin section (2mm) spiral CT guidance in all cases with an 11 G radiofrequency-compatible coaxial needle and 2mm coaxial drill system and 1.0 cm active tip 17 G non-cooled radiofrequency needle. RFA was performed at 90 degrees C for a period of 6 min. After needle removal, 0.5-1.0 ml absolute alcohol (99.8% concentration) was injected directly into the nidus using a 20 G needle. Patients were discharged within 24h and followed up clinically (at 1 week, 1 month and every 3 months thereafter).

RESULTS

The technical success rate was 100%. Complications occurred in two patients consisting of local mild cellulitis in entry site and peripheral small zone paresthesia on the anterior part of leg. The follow-up period range was 13-48 months (mean+/-SD, 28.2+/-7.4 months). Prompt pain relief and return to normal activities were observed in 52 of 54 patients. Recurrent pain occurred in two patients after a 1 and 3 months period of being pain free, respectively; a second RFA and alcohol ablation was performed achieving successful results. Primary and secondary clinical success rates were 96.3% (52/54 patients) and 100% (2/2 patients), respectively.

CONCLUSION

Percutaneous osteoid osteoma treatment with combination of radiofrequency and alcohol ablation is safe, effective and minimally invasive with high primary and secondary success rates. Persistent or recurrent lesions can be effectively re-treated.

Radiofrequency ablation of intra-articular osteoid osteoma of the hip

Diagnosis and treatment of intra-articular osteoid osteoma is challenging. We present 16 patients with intra-articular osteoid osteomas of the hip treated with percutaneous radiofrequency ablation. Eight osteoid osteomas were located in the femoral head, six in the femoral neck, and two in the acetabulum. Three of the 16 patients had had an incorrect previous diagnosis. Percutaneous radiofrequency ablation was a clinical and technical success in all 16 patients. Within the first 24 h after the procedure, pain improved in all patients. Five patients had pain relief within the first 3 days after the procedure, nine patients within the first week and two patients within 2 weeks. Residual or recurrent symptoms were not reported by the last follow-up. At the 12-month follow-up, computed tomography and magnetic resonance imaging showed complete ossification and bone regeneration at the site of the lesion in three patients, partial ossification in six patients and no changes in seven patients. Computed tomography-guided percutaneous radiofrequency ablation is a simple, minimally invasive, safe and effective method for the treatment of most intra-articular osteoid osteomas.

[Osteoid osteoma. CT guided drilling and radiofrequency ablation]

BACKGROUND

The CT-guided therapy of osteoid osteoma instead of older methods such as open resection has the advantage of exact localization of the nidus intraoperatively and exact documentation of its ablation. Another advantage is the less invasive approach.

PATIENTS AND METHODS

A total of 52 patients with osteoid osteoma were treated in our institution between 1996 and 2005 either by radiofrequency ablation (n=11) or by percutaneous resection under CT guidance (n=41). Their age was between 7 and 48 years, mean age was 22.3 years, and follow-up was 31.3 months.

RESULTS

In all patients (n=52) the osteoid osteoma was successfully treated. In 50 patients the first treatment resulted in long-term success. In two patients the nidus was first missed; they were successfully treated with another operation using the same technique.

CONCLUSION

The CT-guided operation of osteoid osteoma made the therapy much easier because of the exact localization and the less invasive approach. This technique can be used analogously to tumor biopsy. The advantage is the exact documentation of the biopsy path and the possibility to take specimens.

Osteoid osteoma: CT-guided radiofrequency ablation using a water-cooled probe

BACKGROUND

The purpose of this study was to assess the safety and efficacy of computed tomography (CT) guided percutaneous radiofrequency (RF) ablation of osteoid osteoma by using the water-cooled probe.

METHODS

During the period from July 2002 to February 2006, fifty-one patients with osteoid osteomas localized in femur (29), tibia (10), calcaneus (2), talus (2), metatarsus (2), humerus (1), sacrum (1), scapula (1), olecranon (1), patella (1) and thoracic vertebra (1) were treated with CT-guided RF ablation using the Cooltiptrade mark Tyco Healthcare probe. Mean age was 20 (range, 3.5-57 years) and male to female ratio was 36/15. Mean follow-up period was reported 2 years (range, 9-51 months). The procedures were carried out under general anesthesia and the patients were discharged from the hospital within 24 h.

RESULTS

Technical failure was reported in only one procedure. Pain disappeared postoperatively in all the patients within 2-3 days and no patients needed analgesic treatment after a week. All patients were allowed fully weight bear and function without limitation after the procedure. Recurrence of the pain was observed in one patient who was treated successfully with a second ablation. Our primary and secondary clinical success rates were 98 and 100% respectively. In one case, wound infection was observed after the procedure as the only post-operative complication in our series.

CONCLUSION

CT-guided percutaneous RF ablation of osteoid osteomas using the water-cooled probe is a safe, effective and minimally invasive procedure with high success rate and lack of relapses.

Percutaneous radiofrequency ablation for osteoid osteoma: experience with a new treatment

OBJECTIVE

To review our experience with percutaneous radiofrequency ablation (RFA) for osteoid osteoma.

PARTICIPANTS, DESIGN AND SETTING

Retrospective review of 24 patients with osteoid osteoma treated with percutaneous RFA at St Vincent's Hospital, Melbourne, from August 2000 to February 2005.

MAIN OUTCOME MEASURES

Initial response to treatment, return of symptoms, time to recurrence, complications and histopathological correlation.

RESULTS

In 23 of 24 patients, there was immediate relief of symptoms. One-third of patients had a return of symptoms. The 24 patients underwent a total of 32 RFA procedures. Of the eight patients who had a recurrence, five had an initial lesion > or = 10 mm in maximum diameter. Twenty-three of the 24 patients were pain-free at the end of the study period. Patients were followed up for a median of 26 months. There were no long-term complications.

CONCLUSIONS

Percutaneous RFA is a safe and efficacious treatment for osteoid osteoma with a low morbidity rate. Despite recurrence after treatment, re-treatment is simple and effective.

Case reports: an unusual complication of radiofrequency ablation treatment of osteoid osteoma

Osteoid osteoma is a benign bone tumor traditionally treated nonoperatively or by operative excision. However, radiofrequency ablation is being used increasingly for treatment, as there are several reports supporting its effectiveness. Radio-frequency ablation is precise, minimally invasive, safe, effective, and associated with minimal complications and reduced use of healthcare resources. We report a patient treated with radiofrequency ablation for tibial osteoid osteoma and thermal necrosis of the skin.

MRI Features After Radiofrequency Ablation of Osteoid Osteoma with Cooled Probes and Impedance-Control Energy Delivery

OBJECTIVE

The purposes of our study were to determine the temporal changes in MR signal in bone after radiofrequency ablation of osteoid osteoma and the size of the zone of marrow signal change produced by the radiofrequency technique and to compare the size of the zone with published data for radiofrequency ablation with manual-control protocols.

MATERIALS AND METHODS

Radiofrequency ablation was performed in 10 patients with a clinical and radiologic diagnosis of osteoid osteoma. A cooled radiofrequency probe was inserted in the nidus. Twelve minutes of radiofrequency energy was applied from a 200-W radiofrequency generator in an impedance-control setting. MRI with multiplanar turbo spin-echo T1-weighted and STIR sequences was performed at 1, 7, and 28 days after the procedure in seven patients. The three remaining patients had follow-up imaging at 28 days only. The images were reviewed by two radiologists who categorized the imaging features and measured the marrow zone of signal alteration when visible. The size of the zone of marrow signal change produced by the radiofrequency technique was compared with published data for radiofrequency ablation with manual-control protocols.

RESULTS

A 1-mm band of homogeneous altered marrow signal distributed symmetrically parallel to the entire probe tract was seen earliest, at 1 day, in the femoral neck lesion treated with the 2-cm probe. The band was low signal on the T1 sequence and high signal on the STIR sequence, and the diameter of the zone was 27 mm. By 7 days, five of the seven treated bones showed a band of marrow signal alteration. By 28 days, all 10 treated bones had a band of marrow signal alteration. The interband distance at 90 degrees to the probe measured on STIR images at 28 days was a mean of 20.9 mm (confidence interval, 16.1-25.7 mm [p < 0.05]; range +/- measurement error, 10.5-35 +/- 1.64 mm) with a 1-cm probe and 30.5 mm (measurement error, +/- 0.78 mm) on T1 images without contrast material when a 2-cm exposed-tip probe was used. Higher-output generators with impedance-control software and internally cooled radiofrequency probes with longer exposed tips produce larger zones of marrow signal change than expected with manual-control protocols.

CONCLUSION

MRI allows detection of temporal marrow signal change after radiofrequency ablation. The marrow signal change with a high-energy delivery protocol is larger than manual-control protocols.

The management of osteoid osteoma: updates and controversies

PURPOSE OF REVIEW

Osteoid osteoma is a benign painful bone tumor usually found in the lower extremities of children and young adults. It has been traditionally treated by surgical excision. Despite the small size of the lesion, the operative procedure for its removal can be extensive, but still sometimes remains incomplete. The purpose of this review is to highlight and discuss current developments in the management of osteoid osteoma.

RECENT FINDINGS

During the past decade, efforts were deployed to minimize bone removal, lessen the risk of pathologic fracture and the need for bone grafting, and thereby shorten the period of convalescence. Improved methods for the precise localization of an osteoid osteoma with use of radioisotope scanning or computed tomography scan have made it possible to treat this lesion with more limited and effective operations, mainly in deep and non-easily accessible osteoid osteomas.

SUMMARY

Although they bear the criticism of lacking histological proof for diagnosis of osteoid osteoma, minimally invasive techniques, such as computed tomography-guided percutaneous radiofrequency thermal ablation and laser photocoagulation have become the methods of choice for the treatment of all localizations except those in contact with neural structures (awaiting further research and experience), provided that the diagnosis is based on a typical clinical, scintigraphic and computed tomography presentation.

Osteoid Osteoma: Experience with Laser- and Radiofrequency-Induced Ablation

The purpose of this study was to analyze the clinical outcome of osteoid osteoma treated by thermal ablation after drill opening. A total of 17 patients and 20 procedures were included. All patients had typical clinical features (age, pain) and a typical radiograph showing a nidus. In 5 cases, additional histological specimens were acquired. After drill opening of the osteoid osteoma nidus, 12 thermal ablations were induced by laser interstitial thermal therapy (LITT) (9F Power-Laser-Set; Somatex, Germany) and 8 ablations by radiofrequency ablation (RFA) (RITA; StarBurst, USA). Initial clinical success with pain relief has been achieved in all patients after the first ablation. Three patients had an osteoid osteoma recurrence after 3, 9, and 10 months and were successfully re-treated by thermal ablation. No major complication and one minor complication (sensible defect) were recorded. Thermal ablation is a safe and minimally invasive therapy option for osteoid osteoma. Although the groups are too small for a comparative analysis, we determined no difference between laser- and radiofrequency-induced ablation in clinical outcome after ablation.

Tratamento de osteoma osteóide de corpo vertebral da coluna lombar por ablação por radiofreqüência

Neste artigo descreveremos um raro caso de osteoma osteóide de corpo vertebral da quarta vértebra lombar com epidemiologia não usual (42 anos), diagnosticado através da história clínica, exame físico, cintilografia, tomografia e ressonância magnética. O diagnóstico foi confirmado por biópsia guiada por tomografia, e o tratamento minimamente invasivo efetuado com sucesso através da abalação com radiofreqüência guiada por tomografia.

Osteoid Osteoma in an ex Vivo Animal Model: Temperature Changes in Surrounding Soft Tissue during CT-guided Radiofrequency Ablation

PURPOSE

To assess temperature changes in the soft tissue surrounding bone during radiofrequency (RF) ablation of osteoid osteoma in an ex vivo animal model.

MATERIALS AND METHODS

Intracortical cavities were created in fresh bovine long bone specimens obtained from a slaughterhouse as models for osteoid osteoma. Three groups of three specimens each were defined according to the thickness (1, 3, and 5 mm) of the cortical bone lamella separating the nidus from the periosteum. Three thermocouples were applied to the soft tissue surrounding the bone in defined distances (0, 5, and 10 mm) from the periosteum. Before RF ablation, the thickness of the cortical bone lamella was documented at computed tomography. Specimens were heated in a 37 degrees C basin. As soon as the measured temperature in the cavity of the specimen reached 35 degrees C, RF ablation was performed for 400 seconds, with a target temperature of 95 degrees C. During RF ablation, continuous measurements were performed simultaneously with digital thermometers. No simulation of vessel perfusion was used. The effect of the thickness of residual osseous lamella and the effect of the distance between the thermocouple and the periosteum were tested with an analysis of variance. Post hoc Bonferroni tests were performed.

RESULTS

Mean maximum temperatures of 69.1 degrees, 51.3 degrees, and 42.5 degrees C for 1-mm lamella; 59.2 degrees, 46.5 degrees, and 41.1 degrees C for 3-mm lamella; and 50.6 degrees, 44.8 degrees, and 40.0 degrees C for 5-mm lamella were measured 0, 5, and 10 mm, respectively, from the periosteum. Significant temperature differences were shown with analysis of variance and post hoc tests for the three groups of bone lamella thickness and distance (P < .001).

CONCLUSION

In the model of osteoid osteoma, the surrounding temperature (soft tissue) during RF ablation was shown to depend on the thickness of the cortical bone lamella and the distance from the periosteum.

A review of the general aspects of radiofrequency ablation

As an alternative to standard surgical resection for the treatment of malignant tumors, radiofrequency ablation (RFA) has rapidly evolved into the most popular minimally invasive therapy. To help readers gain the relevant background knowledge and to better understand the other reviews in this Feature Section on the clinical applications of RFA in different abdominal organs, the present report covers the general aspects of RFA. After an introduction, we present a simple definition of the energy applied during RFA, a brief historical review of its technical evolution, and an explanation of the mechanism of action of RFA. These basic discussions are substantiated with descriptions of RFA equipment including those commercially available and those under preclinical development. The size and geometry of induced lesions in relation to RFA efficacy and side effects are discussed. The unique pathophysiologic process of thermal tissue damage and the corresponding histomorphologic manifestations after RFA are detailed and cross-referenced with the findings in the current literature. The crucial role of imaging technology during and after RFA is also addressed, including some promising new developments. This report finishes with a summary of the key messages and a perspective on further technologic refinements and identifies some specific priorities.

Osteoid osteoma treated with computed tomography-guided percutaneous radiofrequency ablation: a case series

The nidi of osteoid osteoma are small and difficult to identify precisely; this can necessitate substantial resection of the surrounding normal bone. We applied percutaneous, image-guided radiofrequency ablation to treat 5 patients with osteoid osteoma. The precise location of each nidus was determined using a 3-mm-thick spiral computed tomographic scan. The most appropriate needle pathway was selected to avoid major neural and vascular structures. A 14-gauge core needle was introduced into the nidus and then exchanged for a 17-gauge straight rigid electrode with a 1-cm exposed tip to heat the lesion to 90 degrees centigrade for 5 minutes. Four of the 5 patients were discharged on the day after surgery without any external supports, and were pain-free after a few days. The remaining patient had a pes equinus contracture induced by the penetration of the calf muscles through a posterior approach but was fully recovered 6 days later. The mean follow-up period was 20.6 months. No recurrences or late complications were observed in this series. This case series shows that the computed tomography-guided percutaneous radiofrequency ablation is a simple, minimally invasive, and highly effective technique for the treatment of osteoid osteoma.

Osteoid osteoma of the calcaneus: percutaneous radiofrequency ablation

Osteoid osteoma of the foot can pose particular problems in diagnosis, especially when positioned in a juxta-articular location. It can cause reactive synovitis and simulate arthritis without periostitis. An atypical presentation may delay diagnosis and thus delay treatment. Different modes of treatment have been described including medical management with nonsteroidal, antiinflammatory drugs, and open surgical resection with intralesional, marginal, or wide surgical margins. In recent years, several computed tomography-guided percutaneous techniques have been used to achieve ablation of the nidus with minimal tissue invasion. We report a case of a 39-year-old man with an 8-month history of persistent foot pain who underwent percutaneous radiofrequency ablation of an osteoid osteoma involving the calcaneus. The patient related an immediate relief of pain and had no recurrence of symptoms or the lesion at 3-year follow-up.

Osteoid Osteoma of the Spine is an Important Cause of Back Pain: Two Cases and Review

Two cases are reported and discussed of osteoid osteoma in the spines of two children, presenting as nocturnal low back pain irrelevant to any position or activity. Plain radiographs of the lumbosacral spine, Technetium-99 bone scan and computerized tomography (CT) were used to locate and verify the lesions. Both were then excised by open surgery and confirmed by a post-operative CT scan. A review of all the known and updated modalities of diagnosis and treatment is presented and it is emphasized that this uncommon lesion should be considered in the differential diagnosis of back pain in children.

Percutaneous radiofrequency thermocoagulation of osteoid osteomas: factors affecting therapeutic outcome

OBJECTIVE

To examine factors which affect local recurrence of osteoid osteomas treated with percutaneous CT-guided radiofrequency thermocoagulation.

DESIGN AND PATIENTS

A prospective study was carried out on 45 patients with osteoid osteoma who underwent percutaneous radiofrequency thermocoagulation with a minimum follow-up of 12 months.

RESULTS

There were seven local recurrences (16%); all occurred within the first year. Local recurrence was significantly related to a non-diaphyseal location (P<0.01). There was no significant relationship (P=0.05) between local recurrence and age of the patient, duration of symptoms, previous treatment, size of the lesion, positive biopsy, radiofrequency generator used or the number of needle positions. There were no complications.

CONCLUSIONS

Osteoid osteomas in a non-diaphyseal location are statistically more likely to recur than those in a diaphyseal location when treated with CT-guided percutaneous radiofrequency thermocoagulation. This relationship between local recurrence and location has not been previously reported.

Radiofrequency ablation in osteoid osteoma of the finger

The occurrence of osteoid osteomas of the hand is rare and their treatment usually is surgical. A 26-year-old man with an osteoid osteoma in the proximal phalanx of the right middle finger was treated with percutaneous radiofrequency ablation. Two years later he remains free of pain and finger function is normal.

Percutaneous radiofrequency treatment of osteoid osteoma using cool-tip electrodes

OBJECTIVES

To report our experience with percutaneous cool-tip radiofrequency ablation of osteoid osteomas and to evaluate clinical outcome.

METHODS AND MATERIAL

Forty-one patients with clinically and radiologically suspected osteoid osteoma were seen over a 48-month period (27 males and 14 females with a mean age of 18.7 years; range 5-43 years). Thirty-eight patients were treated by computed tomography (CT)-guided percutaneous radiofrequency ablation. The procedure was performed under regional or general anaesthesia. After location of the nidus, a 14G-bone biopsy needle is introduced into the nidus. Sampling is performed with a 17G-bone biopsy needle using a coaxial technique. The radiofrequency needle with a 10mm active tip (cool-tip) is inserted through the biopsy needle and is connected to the radiofrequency generator for 6-8 min.

RESULTS

Primary success was obtained in 37 patients (97%) with a 100% secondary success rate. All patients are currently pain-free. No major complications occurred. Patients could resume unrestricted normal activity within 24 h.

CONCLUSIONS

Percutaneous radiofrequency ablation of osteoid osteomas is an efficient and safe method that can be considered the procedure of choice for most cases.

Minimally invasive techniques in orthopedic oncology: radiofrequency and laser thermal ablation

Image-guided percutaneous thermal ablation is a safe and effective method to reduce pain in patients with painful bone tumors. Computed tomography-guided radiofrequency or laser ablation is the modality of choice for most osteoid osteomas. Radiofrequency or laser thermal ablation also offers an alternative method for palliation of localized, painful osteolytic metastatic lesions. Pain can be reduced and neural damage prevented, improving the quality of life for patients with cancer who often have multimorbid conditions and limited life expectancy. A multidisciplinary approach that includes orthopedic surgeons, neurosurgeons, medical and radiation oncologists, and interventional radiologists is essential to manage these patients.

Radiofrequency thermoablation of primary non-spinal osteoid osteoma: optimization of the procedure

Osteoid osteoma is a small benign tumor that requires treatment due to the intense pain it causes. Surgical therapy has been the ablative technique of choice after a failure of medical therapy. Recently, numerous less invasive, alternative procedures have been proposed: drill trepanation with or without ethanol injections, cryoablation, and thermoablation with laser or radiofrequency. The aim of this review is to retrospectively assess the effect of radiofrequency (RF) thermoablation in the treatment of primary non-spinal osteoid osteoma. From June 2001 to July 2003, we treated 106 patients affected by osteoid osteoma with RF thermoablation. Five patients with spinal osteoid osteoma and four with a previously treated osteoma were excluded from the study. In this paper, we assess the results obtained in a selected group of 97 primary non-spinal osteoid osteoma. The lesions were predominantly in the metaphysics of the femur. Central nidus calcifications were frequent and there was no prevalence for which side they occurred. Primary success was achieved in 82 patients (85%), while we obtained secondary success in 15 patients (15%). In two patients (2%), pain persisted between the two treatments and failed to be resolved, even after the second treatment; therefore, surgical excision was performed and complete resolution was obtained. No complications were reported. In conclusion, our results confirm that the treatment of choice for non-spinal osteoid osteoma is RF thermoablation, offering several advantages over ablative techniques.

Thermocoagulation percutanée scannoguidée de l’ostéome ostéoïde

PURPOSE OF THE STUDY

Progress in medical imaging has improved recognition and management of osteoid osteoma. The purpose of this study was to assess the efficacy of computed tomography (CT)-guided percutaneous thermal ablation and discuss the advantages and disadvantages.

MATERIAL AND METHODS

We reviewed retrospectively 33 consecutive patients with osteoid osteoma who had undergone CT-guided radiofrequency ablation. The diagnosis was established on the basis of the clinical presentation and pathognomonic radiographic findings (CT and bone scintigram) without histological proof. We recorded patient age and gender, tumor location, clinical signs and duration, imaging findings, duration of the ablation procedure, type of anesthesia, hospital stay, and complications. We evaluated their effect on final outcome.

RESULTS

Weight-bearing was possible in all patients with a lesion of the lower limb a few hours after surgery. Patients resumed their normal activities in 24-48 hours. Pain resolved immediately after radiofrequency ablation in 26 patients and limping, when present, disappeared within 24 hours. At mean follow-up of 34 months (minimum 12 months) there was one case of recurrent pain. Clinical cure was confirmed by CT and bone scintigraphy in twelve patients.

DISCUSSION AND CONCLUSION

This precise and minimally invasive method is an effective and safe way to reduce healthcare expenditures. It can be recommended as the primary treatment for osteoid osteoma.

Wide surgical excision for osteoid osteoma. Should it be the first-choice treatment?

Osteoid osteomas (OO) are benign skeletal tumors with a predilection for the long bones of young patients. Many different methods are used for their treatment, conservative or operative, less or more radical, with variable technology applications to destroy the "nidus." We present 38 patients with OO who were treated in our hospital between 1995-2001. Their medical records and radiographs were retrospectively reviewed, and the patients were contacted and interviewed by telephone. In 32 patients, OO were located in the lower limb, in two the upper limb, and in four the spine. Thirty-seven patients were treated operatively using open wide excision of the nidus. In 22 of those patients, additional bone grafting was used. In three patients, prophylactic internal fixation was applied to the bone. Two patients developed deep-vein thrombosis; another two had increased pain in the anterior superior iliac spine from the bone graft harvesting area. We had one recurrence, which was treated with a second operation. We conclude that although the traditional method of treatment is wide surgical excision, this technique has increased morbidity and higher risk for complications compared to more minimally invasive procedures. We suggest that it should be the first choice of treatment for either spinal or recurrent OO.

CT-guided radiofrequency ablation of osteoid osteoma: long-term results

The aim of the study was to assess the safety and efficacy of CT-guided percutaneous radiofrequency (RF) ablation of osteoid osteoma (OO). From 1997 to 2001, RF ablation was performed on 38 patients with OO, diagnosed clinically and by radiography, scintigraphy, contrast-enhanced MRI, and CT. Treatment was performed via percutaneous (n=29) or surgical (n=9) access, under CT guidance in all cases, with an 18-gauge straight electrode. Patients were discharged within 24 h and followed up clinically (at 1 week and every 6-12 months) and with MRI (at 6 months) and scintigraphy (after 1 year). The technical success rate was 100%. Complications occurred in two patients, consisting in local skin burns. The follow-up range was 12-66 months (mean +/- SD, 35.5+/-7.5 months). Prompt pain relief and return to normal activities were observed in 30 of 38 patients. Persistent pain occurred in eight patients; two patients refused further RF ablation and were treated surgically; RF ablation was repeated in six cases achieving successful results in five. One patient reported residual pain and is being evaluated for surgical excision. Primary and secondary clinical success rates were 78.9 (30/38 patients) and 97% (35/36 patients), respectively. CT-guided RF ablation of OO is safe and effective. Persistent lesions can be effectively re-treated. Several imaging modalities are needed for the diagnosis of OO and for the follow-up after treatment, particularly in patients with persistent symptoms.