Radiation dosimetry of intraoperative cone-beam compared with conventional CT for radiofrequency ablation of osteoid osteoma

Computer-navigated, stereotactic navigation for percutaneous radiofrequency ablation of osteoid osteomas: dose comparison and procedure times

PURPOSE

Treatment of medication-refractory osteoid osteoma is typically performed with minimally-invasive percutaneous techniques, such as radiofrequency ablation. Given the typically young age of the population of patients being treated, we sought to assess whether using a 3D CT guidance system reduces the number of required probe repositionings and the number of required CTs to validate probe positioning in order to reduce the radiation dosage to the patient.

METHODS

We retrospectively reviewed the records of 19 patients who underwent procedures at our clinic amounting to a total of 27 ablations between 2012 and 2022. At the time of each procedure, the operating physician made the decision whether or not to use stereotactic navigation assistance. We analyzed the data using a Bayesian approach to elucidate possible differences between procedures conducted with or without navigation.

RESULTS

Our results showed a statistically and clinically-significant administration of, on average, 200 mGy*cm greater radiation dosage to the patient when stereotactic navigation was used to guide RFA probe placement for ablation of osteoid osteomas compared with not using navigation assistance. There was a trend towards requiring one fewer probe repositioning with navigation assistance, however this was not statistically conclusive. There was no difference in the time required to achieve the target probe placement or in total procedure duration whether stereotactic navigation was used or not.

CONCLUSION

When utilizing a 3D-guided stereotactic navigation system, there is likely a learning phase before the potential benefits of such a system are realized. Additional radiation administration to the patient may result from the operator learning to properly use and trust the system. In our case, the data also likely reflect a bias in operator choice to use the navigation system when the lesions are more difficult to correctly target or multiple ablation positions are necessary, while choosing conventional imaging assistance for easily targetable tumors, which may conceal some of the benefit of using the navigation system.

Intraoperative cone-beam computed tomography-guided curettage for osteoid osteoma

Recently, cone-beam computed tomography (CBCT)-guided surgeries have been developed for bone and soft tissue tumors. The present study aimed to evaluate the efficacy of CBCT-guided curettage for osteoid osteoma. Our study population included 13 patients who underwent primary curettage for osteoid osteoma using intraoperative CBCT in a hybrid operating room between April 2019 and November 2022. We collected the following data: sex, age, follow-up period, symptom onset to time of surgery, tumor size and location, length of skin incision, operating time, radiation dose, recurrence, postoperative complications, and visual analog scale for pain during the last follow-up. There were 10 male and 3 female patients, and the mean age was 25.0 years (range, 9-49 years). The mean follow-up period was 10.6 months (range, 0.4-24.0 months). The locations of the tumors were the proximal femur in 6 patients, the acetabular region in 2 patients, and the ilium, tibial shaft, calcaneus, cuboid, and talus in 1 patient each. The mean time of symptoms onset to surgery was 18.7 months (range, 2.3-69.9 months). The mean maximum diameter of the tumor was 5.9 mm (range, 3.5-10.0 mm). The mean length of the skin incision was 2.2 cm (range, 1.5-3.5 cm). The mean operating time was 96.9 minutes (range, 64-157 minutes). The mean dose of radiation was 193.2 mGy (range, 16.3-484.0 mGy). No recurrences, postoperative complications, and reoperation were observed in this study. All the patients reported 0 mm on the visual analogue scale for pain on the last follow-up. CBCT-guided curettage for osteoid osteoma was minimally invasive and reliable. This procedure can be effective for the treatment of lesions found in deep locations such as the pelvic bone and proximal femur or an invisible lesion that cannot be detected by regular fluoroscopy.

Intraoperative Radiation Exposure from O-arm-based 3D Navigation in Spine Surgery

INTRODUCTION

Intraoperative three-dimensional (3D) imaging guide technology, such as the O-arm surgical imaging system, is a beneficial tool in spinal surgery that provides real-time 3D images of a patient's spine. This study aims to determine the exposure dose from intraoperative O-arm imaging.

METHODS

A consecutive retrospective review of all patients undergoing spinal surgery was conducted between June 2019 and August 2022. Demographic and operative data were collected from electronic medical records.

RESULTS

Intraoperative O-arm imaging was conducted in 206 (12.9%) of 1599 patients, ranging from one to 4 scans per patient (1.17±0.43 scans). Single O-arm imaging enabled navigation of seven vertebrae in the cervical spine, seven in the thoracic spine, five in the thoracolumbar spine, and four in the lumbar spine on average. The number of O-arm shots per surgery was 1.15±0.36, 1.06±0.24, 1.61±0.7, and 1.07±0.25 for cervical, thoracic, thoracolumbar, and lumbar spinal cases, respectively. The exposure doses represented by dose length products in single O-arm imaging were 377±19 mGy-cm, 243±22 mGy-cm, 378±38 mGy-cm, and 258±11 mGy-cm for cervical, thoracic, thoracolumbar, and lumbar spine cases, respectively. We observed a weak positive correlation between the number of fused spinal levels and the exposure dose.

CONCLUSIONS

Intraoperative radiation exposure from O-arm imaging was lower than the national diagnostic reference levels in Japan established based on the International Commission on Radiological Protection publication, demonstrating its safety from the standpoint of radiological protection in most cases. In surgeries with a large range of fixations, such as corrective deformity surgery, the number of imaging sessions and the amount of intraoperative radiation exposure would increase, leading surgeons to pay attention to the risk of radiation in spinal surgery.

A CT-free protocol to treat osteoid osteoma of the hip region in childhood and adolescence by percutaneous drilling and by hip arthroscopy

INTRODUCTION

It is often difficult to clinically and radiologically diagnose intra-articular osteoid osteomas and osteoid osteomas of the hip joint. Treatment can also be difficult due to complex locational relationships. CT-guided radiofrequency ablation is currently the standard form of treatment.In this paper we report on a minimally-invasive concept for treating osteoid osteomas near the hip joint in children and adolescents which does not involve using computed tomography.

MATERIAL AND METHOD

10 patients with an average age of 12.1 years underwent treatment for osteoid osteomas in the hip joint region. The diagnosis was made using a contrast-enhanced MRI. The osteoid osteomas were marked percutaneously using x-ray and MRI guidance. MRI-guided drilling/curettage was performed in 4 cases and arthroscopic resection in 6 cases.

RESULTS

All lesions were successfully treated using the MRI-guided method. All patients were free of pain after the treatment. There was no instance of recurrence during the follow-up period, which averaged 10 months. The effective dose for marking the lesion was between 0.0186 mSv and 0.342 mSV (mean 0.084 mSV).

CONCLUSIONS

Our MRI diagnostics protocol, the MRI-guided drilling and the minimally invasive hip arthroscopy represent an alternative to CT-guided radiofrequency ablation in the treatment of osteoid osteomas. Radiation exposure can thereby be significantly reduced. Hip arthroscopy can also be used to treat secondary pathologies such as femoroacetabular impingement.

O-Arm-Navigated, Robot-Assisted Versus Conventional CT Guided Radiofrequency Ablation in Treatment of Osteoid Osteoma: A Retrospective Cohort Study

Background

Osteoid osteoma is a common benign bone tumor, and clinically there is severe local pain that typically worsens at night. The conventional CT-guided radiofrequency ablation (RFA) was widely used in the treatment of osteoid osteoma (OO), which could result in some radiation-related and imprecise complications due to the overdose of radiation exposure. This study aimed to compare the surgical effect of robot-assisted RFA with O-arm navigation and conventional CT-guided RFA in the treatment of OO.

Methods

Sixty-two patients who underwent robot-assisted RFA with O-arm navigation (Robot-RFA, n = 24) or CT-guided RFA (CT-RFA, n = 38) were included in this retrospective cohort study. The mean follow-up time was 23.3 months. The intra-operative data, primary technical success rate, visual analog scale (VAS), and post-operative complications were analyzed.

Results

Primary technical success was obtained in 23 patients who had robot-assisted RFA, and 35 patients who had conventional CT-guided RFA. One patient in Robot-RFA group and three patients in CT-RFA group with pain recurrence received repeat-RFA and had a secondary success. Mean operation time and dose of radiation exposure were lower in Robot-RFA group than that in CT-RFA group. The Robot-RFA group took fewer K-wire adjustment times for each patient than the CT-RFA group. There was a statistically significant difference in the mean operation time, dose of radiation exposure, and K-wire adjustment times between the groups (p < 0.05). No complications associated with the procedure were reported in the two groups during the follow-up period.

Conclusion

Robot-assisted RFA with O-arm navigation is a safer and more precise strategy in the treatment of osteoid osteoma with less operation time and radiation exposure compared with the conventional CT-guided radiofrequency ablation.

Finite Element Analysis Could Predict and Prevent a Pathological Femoral Shaft Fracture after En Bloc Resection of a Large Osteoid Osteoma

Osteoid osteoma is a benign tumor. Approximately 20% of these tumors are located in the femur. The tumor primarily occurs in children and is treated by surgical excision or radiofrequency ablation. Recently, bone-tumor resection using three-dimensional (3D) intraoperative imaging with an O-arm in combination with a navigation system has been reported to be effective. However, there is a risk of postoperative fracture because of the weakening of the bone after drilling for tumor resection. A 12-year-old Japanese girl presented with an osteoid osteoma in the left femoral shaft, which resulted in a fracture after en bloc resection and artificial bone grafting using a 3D image-guided (O-arm) assisted navigation system. Orthopedic oncologists should be aware of the risk of fracture. Moreover, they should consider the mechanical risk prediction of bone fracture using finite element analysis prior to treatment.

Cone beam computed tomography (CBCT) guidance is helpful in reducing dose exposure to pediatric patients undergoing radiofrequency ablation of osteoid osteoma

Purpose

To assess efficacy and safety of cone beam computed tomography (CBCT) in the radiofrequency ablation (RFA) of osteoid osteoma (OO) in children and adolescents, and to compare technical success, clinical success, radiation dose and procedure duration time of CBCT guidance to conventional computed tomography (CT) guidance.

Materials and methods

Between 2015 and 2019, 53 consecutive percutaneous RFA were performed on pediatric patients with CBCT or conventional CT guidance, respectively, in 24 and 29 children and adolescents with 24-month follow-up. Dose area product (DAP) and dose length product (DLP) were recorded, respectively, for CBCT and conventional CT and converted to effective doses (ED).

Results

CBCT and conventional CT groups were similar in terms of patient age and weight, tumor size and tumor location. Technical success was achieved in all cases. Primary clinical success was 91.67% (22/24) for the CBCT group and 89.66% (26/29) for the conventional CT group. Mean DAP was 64.75Gycm2 (range 6.0–266.7). Mean DLP was 972.62mGycm (range 337–2344). ED was significantly lower in the CBCT group compared to the conventional CT group (0.34 mSv vs. 5.53 mSv, p = 0.0119). Procedure duration time was not significantly longer in the CBCT group (102.25 min vs. 92.34 min, p = 0.065). No major complication was registered. Minor complications were observed in 4 patients (2 in CBCT; 2 in conventional CT).

Conclusions

Compared to conventional CT guidance, CBCT guidance for percutaneous OO ablation shows similar technical and clinical success rates, with reduced radiation dose and equivalent procedure duration time. This technique helps sparing dose exposure to pediatric patients.

CT-guided radiofrequency ablation for osteoid osteomas: a systematic review

OBJECTIVES

CT-guided radiofrequency ablation (CT-RFA) is considered to be the gold standard for treatment of osteoid osteoma (OO) yet treatment failures (TFs) continue to be reported. This systematic review was conducted to evaluate factors associated with TF, such as ablation time, lesion location, and patient age as well as evaluating how TF has trended over time.

METHODS

Original studies reporting on patients undergoing CT-RFA of OO published between 2002 and 2019 were identified. TF was defined as patients with (1) recurrent or persistent pain +/- (2) imaging evidence of persistent OO. TFs were subdivided into those occurring after the index procedure (primary TF) or those occurring after repeat RFA (secondary TF). Subgroup analysis was performed for TF based on the study date (2002-2010 or 2010-2019), time duration of ablation at 90 °C (6 min or > 6 min), patient age, and tumor location (spinal vs. appendicular).

RESULTS

Sixty-nine studies were included for a total of 3023 patients. The global primary TF rate was 8.3% whereas the secondary TF rate was 3.1%. The TF rate reported in studies published after 2011(7%) was about half that during the earlier time period 2002-2010 (14%). There was no statistical difference in TF corrected for age, OO location, or duration of ablation (respectively p = 0.39, 0.13, and 0.23). The global complication rate was 3%, the most frequent being skin burns (n = 24; 0.7%).

CONCLUSIONS

A decrease in TF observed between 2011-2019 compared to 2002-2010 may reflect improvements in operator technique or advancements in equipment. Duration of ablation, patient age, or location of OO failed to significantly correlate with TF.

KEY POINTS

• CT-guided radiofrequency ablation of osteoid osteomas is a safe technique with a low rate of treatment failure (8.3% failure rate after the primary radiofrequency reducing to 3.1% following a secondary treatment). • The treatment failure rate has decreased over time, possibly due to an improved understanding of the disease process, better technique, and advances in equipment. • Duration of ablation, patient age, or lesion location did not significantly correlate with treatment failure.

Percutaneous thermal ablation for treatment of osteoid osteoma: a systematic review and analysis

OBJECTIVE

Although radiofrequency ablation is well validated for treatment of osteoid osteoma, newer technologies, namely cryoablation, have been less thoroughly studied. The purpose is to perform a systematic review and pooled analysis of percutaneous ablation technologies for treatment of osteoid osteoma with subset analysis of intra-articular and spinal tumors.

MATERIAL AND METHODS

A total of 36 of 79 identified manuscripts met inclusion criteria, comprising 1863 ablations in 1798 patients. Inclusion criteria were (1) retrospective or prospective analysis of thermal ablation of osteoid osteomas in any location, (2) at least 6 months of clinical follow-up, (3) 10 or more patients, (4) patients not included in a second study included in this review, and (5) English language or English translation available. Success rate was defined as all ablations minus technical failures, clinical failures, and recurrences. Subset analysis of intra-articular and spinal tumors was performed.

RESULTS

Overall success rate was 91.9% (95% CI 91-93%). Technical failure, clinical failure, and recurrence rates were 0.3%, 2.1%, and 5.6% respectively. Complications were seen in 2.5% (95% CI 1.9-3.3%) patients. There was no significant difference when comparing radiofrequency ablation and cryoablation (p = 0.92). Success rates for intra-articular (radiofrequency ablation) and spinal tumors (radiofrequency and cryoablation) were 97% and 91.6% respectively.

CONCLUSION

Percutaneous ablation of osteoid osteomas was highly successful with low complication rates. Efficacy of radiofrequency ablation and cryoablation is similar, which is consequential because cryoablation is associated with decreased pain, predictable nerve regeneration, and theoretical immunotherapy benefits. Treatment of more challenging intra-articular and spinal lesions demonstrated similarly high success and low complication rates.

3D imaging and stealth navigation instead of CT guidance for radiofrequency ablation of osteoid osteomas: a series of 52 patients

Background

Osteoid osteomas are benign bone neoplasms that may cause severe pain and limit function. They are commonly treated by radiofrequency ablation (RFA) through a needle inserted into the nidus of the lesion under CT guidance, which is associated with exposure of young patients to relatively high dose of radiation. The objective of this study was to investigate the amount of radiation, effectiveness and safety of an alternative imaging approach, the 3D image-guided (O-arm) technology and the Stealth navigation.

Methods

We retrospectively reviewed 52 electronic medical files of patients (mean age 24.7 years, range 8–59 years) who were treated with thermal ablation of benign osteoid osteomas guided by the navigated O-arm-assisted technique in our institution between 2015 and 2017. Data were extracted on the associated complications, the reduction in pain at 3 months and one year postoperatively, and the amount of radiation administered during the procedure.

Results

The level of pain on a visual analogue scale decreased from the preoperative average of 7.73 to 0 at the 3-month follow-up. The mean dose-length product was 544.7 mGycm² compared to the reported radiation exposure of 1971–7946 mGycm² of CT-guided radio ablations. The one intra-operative complication was a superficial burn in the subcutaneous lesion in a tibia that was treated locally with no major influence on recovery.

Conclusions

RFA ablation guided by 3D O-arm stealth navigation is as effective as the traditional CT-guided technique with the advantage of lower radiation exposure.

Trial registration

Retrospective study number 0388–17-TLV at Tel Aviv Sourasky Medical Center IRB, approved at 25.10.17.

Osteoid Osteoma in Children Younger than 3 Years of Age

We present a case series of four children, younger than 3 years old, with osteoid osteoma of the lower limb. Pain and limping were the main symptoms. With careful clinical examination, we could localize the affected area. Radiological evaluation revealed cortical thickening in 3 children. On MRI examination, we found extensive edema, with normal bony cortices. The central nidus was found in 3 children. CT scan was the most accurate examination which revealed the central nidus with surrounding sclerosis. Bone scans had positive uptake in the affected area. Our patients were treated with an intralesional excision biopsy, with simultaneous radiofrequency ablation in those affected in the femur. Pathological specimens confirmed the diagnosis of osteoid osteoma. There was uneventful recovery of our patients. This case series contributes to the limited description of osteoid osteoma diagnosed and treated in very young children.

C-arm cone-beam computed tomography-guided minimally invasive open excision of an osteoid osteoma undetectable on fluoroscopy: A case report

•

A robotic C-arm cone-beam computed tomography (CBCT) system provides a clear intraoperative visualization of the osteoid osteoma.

•

C-arm CBCT allowed precise access to the tumor, accurate tumor resection, and minimal sacrifice of the normal bone in osteoid osteoma surgery.

•

Repurpose use of the dilator, retractor, and wider trephine tips achieved more conservative results with a smaller skin incision.

Introduction

The small size of a nidus and the extensive sclerosis around it often make it difficult to identify tumors from the surrounding normal bone by fluoroscopy, and a large amount of bone resection might be required to secure complete removal during osteoid osteoma surgery. In this report, we present the first case of radiographically invisible osteoid osteoma that was successfully resected under a robotic C-arm cone-beam computed tomography (CBCT) imaging system.

Presentation of case

A 14-year-old boy presented with persistent pain around the left knee joint was diagnosed with osteoid osteoma of the left distal femur. Since the tumor was not detectable by intraoperative fluoroscopy, a CBCT system was used for guidance during an open tumor resection. For a less invasive surgery, we repurposed the dilator and retractor of the microendoscopic discectomy (MED) system and resected the tumor using the wider trephine tips for bone biopsy. At the final follow-up one year later, the function of the afflicted limb was normal with no complaint of any symptoms. Plain radiograph at the final follow-up showed new bone formation completely filling the bone defect, without local recurrence.

Discussion

CBCT allowed for clear intraoperative visualization of the osteoid osteoma, thereby promising a secure resection and less invasive osteoid osteoma treatment. Furthermore, the repurposed use of the dilator and retractor of the MED system as well as the wider trephine tips for bone biopsy made the procedure less invasive.

Conclusion

CBCT-guided minimally invasive open excision surgery could be a useful option for the management of radiographically invisible osteoid osteoma.

T1 Vertebra Pedicular Osteoid Osteoma: Minimally Invasive Surgical Resection Aided by New Integrated Navigation to 3D Imaging Device

We hereby describe a minimally invasive resection of a T1 pedicular osteoid osteoma next to the vertebral canal. The patient had an 18-month report of painful radiculopathy. We performed the surgery under 3D imaging guidance using navigation with an all-in-one device. Full procedure irradiation was 1.17 mSv for a 181-picture acquisition. Complete operative time incision to closure was 58 minutes. Despite sparing the vertebral stability without any fixation, the tumor resection was well-margined, thanks to the focused guidance. After surgery, the patient had complete relief of his symptoms at the 6-month follow-up. 3D imaging system coupled to navigation made the procedure safe without consuming time. The single Surgivisio® device allows comfortable 3D minimally invasive spine navigation surgery with the ergonomics of a C-arm.

Mini-open excision of osteoid osteoma using intraoperative O-arm/Stealth navigation

BACKGROUND

Although osteoid osteomas have traditionally been treated by surgical excision, radiofrequency ablation (RFA) has gained favor as a less invasive procedure. However, RFA is contraindicated for osteoid osteomas close to the skin or crucial neurovascular structures, and is not covered by national health insurance in Japan. The aim of the present study was to evaluate the efficacy of surgical excision of osteoid osteomas using intraoperative navigation.

METHODS

We performed a retrospective review of five patients with osteoid osteoma who underwent a mini-open excision using O-arm/Stealth navigation at our institution. The osteoid osteomas were excised using a cannulated cutter or curetted out with the assistance of navigation.

RESULTS

Complete excision was achieved in all patients, which was confirmed by pathological examination. The mean skin incision was 2.1 cm (range, 1.5 to 3.0 cm) and the mean duration required for setup three-dimensional image was 15 min (range, 12 to 20 min). Although the mean visual analog scale score was 7 (range, 4 to 8) before surgery, all patients experienced relief from their characteristic pain immediately after surgery, with the mean scores of 2.2 (range, 1 to 3) and 0 at 2 days and 4 weeks after surgery, respectively. There was no intra-operative complication related to the navigation and no recurrence was observed during the mean follow-up period of 25 months (range, 13 to 33 months).

CONCLUSIONS

Mini-open excision using intraoperative O-arm/Stealth navigation is a safe and accurate procedure for patients with osteoid osteoma, which could cover the limitation of RFA.

Reduced-dose C-arm computed tomography applications at a pediatric institution

BACKGROUND

Reduced-dose C-arm computed tomography (CT) uses flat-panel detectors to acquire real-time 3-D images in the interventional radiology suite to assist with anatomical localization and procedure planning.

OBJECTIVE

To describe dose-reduction techniques for C-arm CT at a pediatric institution and to provide guidance for implementation.

MATERIALS AND METHODS

We conducted a 5-year retrospective study on procedures using an institution-specific reduced-dose protocol: 5 or 8 s Dyna Rotation, 248/396 projection images/acquisition and 0.1-0.17 μGy/projection dose at the detector with 0.3/0.6/0.9-mm copper (Cu) filtration. We categorized cases by procedure type and average patient age and calculated C-arm CT and total dose area product (DAP).

RESULTS

Two hundred twenty-two C-arm CT-guided procedures were performed with a dose-reduction protocol. The most common procedures were temporomandibular and sacroiliac joint injections (48.6%) and sclerotherapy (34.2%). C-arm CT was utilized in cases of difficult percutaneous access in less common applications such as cecostomy and gastrostomy placement, foreign body retrieval and thoracentesis. C-arm CT accounted for between 9.9% and 80.7% of the total procedural DAP.

CONCLUSION

Dose-reducing techniques can preserve image quality for intervention while reducing radiation exposure to the child. This technology has multiple applications within pediatric interventional radiology and can be considered as an adjunctive imaging tool in a variety of procedures, particularly when percutaneous access is challenging despite routine fluoroscopic or ultrasound guidance.

Computed tomography guided navigation assisted percutaneous ablation of osteoid osteoma in a 7-year-old patient: the low dose approach

Osteoid osteoma (OO) is a benign tumour that can cause severe pain and functional limitation to children and young adults; the treatment of choice is image-guided ablation. Due to the very small size of the lesion, detection and accurate needle placement may be challenging. Computed tomography (CT) offers very detailed imaging of the skeleton and is the modality of choice for the detection of small OO and for ablation guidance. Nevertheless, CT-guided positioning of the ablation applicator is linked to significant radiation exposure, particularly for the paediatric population. This case describes the successful use of a novel CT-based navigation system that offers the possibility of accurate ablation with only minimal radiation exposure in a paediatric patient.

Pediatric Percutaneous Osteoid Osteoma Ablation: Cone-Beam CT with Fluoroscopic Overlay Versus Conventional CT Guidance

PURPOSE

To compare technical success, clinical success, complications, radiation dose, and total room utilization time for osteoid osteoma thermal (radiofrequency or microwave) ablation using cone-beam computed tomography (CBCT) with two-axis fluoroscopic navigational overlay versus conventional computed tomography (CT) guidance.

MATERIALS AND METHODS

A retrospective review was performed to identify all osteoid osteoma ablations performed over a 5.5-year period at a single tertiary care pediatric hospital. Twenty-five ablations (15 radiofrequency and 10 microwave) in 23 patients undergoing fluoroscopic CBCT-guided osteoid osteoma ablation were compared to 35 ablations (35 radiofrequency) in 32 patients undergoing ablation via conventional CT guidance. Dose area product and dose length product were recorded for CBCT and conventional CT, respectively, and converted to effective doses. Technical success, clinical success (cessation of pain and medication use 1 month after ablation), complications, radiation dose, and total room utilization time were compared.

RESULTS

All procedures were technically successful. Twenty-two of 25 (88.0%) CBCT and 31 of 35 (88.6%) conventional CT-guided ablations achieved immediate clinical success. There were two minor complications in each group and no major complications. Mean effective radiation dose was significantly lower for CBCT compared to CT guidance (0.12 vs. 0.39 mSv, p = 0.02). Mean total room utilization time for CBCT was longer (133.5 vs. 97.5 min, p = 0.0001).

CONCLUSIONS

Fluoroscopic CBCT guidance for percutaneous osteoid osteoma ablation yields similar technical and clinical success, reduced radiation dose, and increased total room utilization time compared to conventional CT guidance.

Percutaneous radiofrequency ablation for osteoid osteoma under guidance of threedimensional fluoroscopy

PURPOSE

To evaluate the outcome of percutaneous radiofrequency ablation under guidance of 3-dimensional fluoroscopy in 17 patients with osteoid osteoma.

METHODS

Records of 11 male and 6 female consecutive patients aged 4 to 28 (mean, 13.8) years who underwent radiofrequency ablation under guidance of 3-dimensional fluoroscopy for osteoid osteoma and were followed up for a mean of 15.8 (range, 12-28) months were reviewed. All patients had been treated with analgesics but failed to achieve lasting pain relief. Visual analogue score (VAS) for pain was assessed pre- and post-operatively. Absence of pain was considered recovery.

RESULTS

The mean operating time was 55 (range, 20-95) minutes, and the mean length of hospital stay was 2.8 (range, 2-7) days. The mean amount of radiation was 390.2 (range, 330.5-423.6) mGy/cm. Relief of pain occurred within the first 24 hours in 11 patients and by the end of the first week in 3 patients. Pain persisted in 3 patients at one month; they underwent revision surgery and achieved complete recovery. The mean VAS for pain was 7.2 (range, 6-9) in 17 patients preoperatively and decreased to 0.64 (range, 0-2) in the 14 patients with pain relief and 0.66 (range, 0-1) in the 3 patients after revision surgery. Two patients had severe discharge from the wound secondary to fat necrosis, which resolved within a week with antibiotics and local dressings. No patient had cellulitis, vasomotor instability, neurovascular injury, fracture, or deep infection.

CONCLUSION

Percutaneous radiofrequency ablation under guidance of 3-dimensional fluoroscopy is a viable treatment option for osteoid osteoma.

Radiofrequency ablation of osteoid osteoma using a three-dimensional navigation system

OBJECTIVE

This study aimed to report the clinical outcomes for patients with osteoid osteoma (OO) treated by radiofrequency ablation (RFA) using a three-dimensional (3D) navigation system.

METHODS

We performed RFA using a 3D navigation system on 32 patients with clinically and radiologically diagnosed OO. This study included 25 males and 7 females with a median age of 20 years (range, 10-39 years). The median duration of follow-up was 18 months (range, 1-65 months). We investigated technical specifications, tumor localization, technical success, clinical success, biopsy success, complications, incomplete treatment, and recurrences.

RESULTS

Eighteen tumors were located in the femur, seven in the tibia, two in the humerus, and one each in the fibula, scapula, patella, lumbar vertebra, and acetabula. All procedures were technically successful, and pain relief was achieved in all patients. However, local recurrence developed in one patient, needing additional RFA. The clinical success rate was 96.8%. Biopsy showed OO in 12 patients (37%). Complications occurred in three patients (9%), two cases of fractures and one of osteomyelitis.

CONCLUSIONS

A 3D navigation provides real-time imaging and enables us to set the RFA needle in the correct position, particularly in case of OO-aroused complex anatomical structures. Our initial results indicated that radiofrequency ablation using a 3D navigation system is feasible and safe for patients with OO.

Radiofrequency Ablation of Osteoid Osteoma with Use of Intraoperative Three-Dimensional Imaging and Surgical Navigation

Introduction

During the performance of radiofrequency ablation of osteoid osteomas, the use of intraoperative cone-beam computed tomography (CT) imaging with surgical navigation lowers radiation exposure while allowing real-time targeting of the nidus.

Step 1 Preoperative Planning

Review all images to confirm a high level of confidence in the radiographic diagnosis.

Step 2 Patient Positioning and Setup

Be sure to position and set up properly.

Step 3 Placement of Tracking Optical Array

Attach the optical array to the target bone.

Step 4 O-Arm Setup Initial CT Imaging for Surgical Navigation and Remote Mouse Registration

Set up the intraoperative CT (O-Arm) machine and acquire the initial images for surgical navigation.

Step 5 CT Data Interpretation and Approach Planning

Analyze the initial images, rotated or positioned as necessary, to allow you to proceed with the planned direction and angle of approach to the nidus.

Step 6 Surgical Navigation Setup

Register the surgical instruments with the surgical navigation unit.

Step 7 Nidus Localization and Kirschner Wire Insertion

Target the nidus and then insert the Kirschner wire into its center.

Step 8 Exchanging Kirschner Wire for a Radiofrequency Probe

Once the accuracy of the Kirschner wire placement is confirmed, exchange it for the radiofrequency probe and perform a CT scan to confirm proper probe placement.

Step 9 Confirmation of RFA Probe Placement

Perform a CT scan to confirm proper placement of the probe within the center of the nidus.

Step 10 Activation of the Radiofrequency Probe and Closure

Perform the radiofrequency treatment to ablate the cells within the nidus.

Results

We conducted a study of three different techniques of radiofrequency ablation.IndicationsContraindicationsPitfalls & Challenges.