CT-guided stereotactic targeting accuracy of osteoid osteoma

Influence of the Vertek aiming device on the surgical accuracy of computer-assisted drilling of the equine distal sesamoid bone-An experimental cadaveric study

OBJECTIVE

To determine the effect of the Vertek aiming device (VAD) on the surgical accuracy of navigated drilling of the distal sesamoid bone (DSB).

STUDY DESIGN

Experimental cadaveric study.

SAMPLE POPULATION

A total of 30 paired equine cadaveric limbs from 15 horses.

METHODS

Each specimen was placed in a purpose-built frame (PBF). Preoperative cone beam computed tomography (CBCT) images were acquired with an imaging unit coupled with a surgical navigation system. In the DSB of each specimen, a 4.5 mm glide hole and a 3.2 mm thread hole were drilled under navigation guidance, to simulate drilling for the repair of a mid-sagittal DSB fracture. In the VAD group navigated drilling was assisted by using the VAD. In the free-hand drilling group navigated drilling was performed without the VAD. Pre-and postoperative CBCT scans were merged and surgical accuracy aberrations (SAA) between the planned drill corridor and the created bone tunnel were measured. Descriptive statistics and repeated-measures analyses of variance (rep.-meas. ANOVA) were performed to compare SAA measurements between the study groups.

RESULTS

The SAA measurements ranged from 0 to 2.9 mm in the free-hand group and from 0 to 2.8 mm in the VAD group. The median overall SAA was lower in the VAD group than in the free-hand navigated group (0.6 mm ± [0.5-0.7] vs. 0.8 mm ± [0.7-1], rep.-meas. ANOVA p = .007).

CONCLUSION

The additional use of the VAD in the described set-up for navigated drilling significantly improved surgical accuracy.

CLINICAL SIGNIFICANCE

The combined use of the VAD and PBF may help improve surgical accuracy in navigated lag screw repair of DSB fractures.

Micro-robotic percutaneous targeting of type II endoleaks in the angio-suite

PURPOSE

Endovascular aneurysm repair has emerged as the standard therapy for abdominal aortic aneurysms. In 9-30% of cases, retrograde filling of the aneurysm sac through patent branch arteries may result in persistence of blood flow outside the graft and within the aneurysm sac. This condition is called an endoleak type II, which may be treated by catheter-based embolization in case of continued sac enlargement. If an endovascular access is not possible, percutaneous targeting of the perfused nidus remains the only option. However, this can be very challenging due to the difficult access and deep puncture with risk of organ perforation and bleeding. Innovative targeting techniques such as robotics may provide a promising option for safe and successful targeting.

METHODS

In nine consecutive patients, percutaneous embolization of type II endoleaks was performed using a table-mounted micro-robotic targeting platform. The needle path from the skin entry to the perfused nidus was planned based on the C-arm CT image data in the angio-suite. Entry point and path angle were aligned using the joystick-operated micro-robotic system under fluoroscopic control, and the coaxial needle was introduced until the target point within the perfused nidus was reached.

RESULTS

All punctures were successful, and there were no puncture-related complications. The pre-operative C-arm CT was executed in 11-15 s, and pathway planning required 2-3 min. The robotic setup and sterile draping were performed in 1-2 min, and the alignment to the surgical plan took no longer than 30 s.

CONCLUSION

Due to the small size, the micro-robotic platform seamlessly integrated into the routine clinical workflow in the angio-suite. It offered significant benefits to the planning and safe execution of double-angulated deeply localized targets, such as type II endoleaks.

Innovations in Image-Guided Procedures: Unraveling Robot-Assisted Non-Hepatic Percutaneous Ablation

Interventional oncology is routinely tasked with the feat of tumor characterization or destruction, via image-guided biopsy and tumor ablation, which may pose difficulties due to challenging-to-reach structures, target complexity, and proximity to critical structures. Such procedures carry a risk-to-benefit ratio along with measurable radiation exposure. To streamline the complexity and inherent variability of these interventions, various systems, including table-, floor-, gantry-, and patient-mounted (semi-) automatic robotic aiming devices, have been developed to decrease human error and interoperator and intraoperator outcome variability. Their implementation in clinical practice holds promise for enhancing lesion targeting, increasing accuracy and technical success rates, reducing procedure duration and radiation exposure, enhancing standardization of the field, and ultimately improving patient outcomes. This narrative review collates evidence regarding robotic tools and their implementation in interventional oncology, focusing on clinical efficacy and safety for nonhepatic malignancies.

Laser Target System in Combination with an Aiming Device for Percutaneous CT-Guided Interventions - An Accuracy Study

RATIONALE AND OBJECTIVES

To evaluate the targeting accuracy of laser-guided punctures in combination with an aiming device for computed tomography (CT) interventions during in vitro experiments. MATERIALS AND METHODS: A total of 600 CT-guided punctures were performed using a laser target system, half of them with the additional help of an aiming device. Conically shaped targets in a plexiglass phantom were punctured. The planning CT data sets were acquired with 1.25, 2.5 and 5 mm slice thickness. Needle placement accuracy, as well as procedural time, was assessed. The Euclidean (ED) and normal distances (ND) were calculated at the target point.

RESULTS

Using the aiming device, the accomplished mean ND at the target for the 1.25, 2.5 and 5 mm slice thickness was 1.76 mm (SD ± 0.92), 2.09 mm (SD ± 1.06) and 1.93 mm (SD ± 1.38), respectively. Without aiming device, the corresponding results were 2.55 mm (SD ± 1.42), 2.7 mm (SD ± 1.43) and 2.31 mm (SD ± 1.64). At a slice thickness of 1.25 mm and 2.5 mm, punctures with the aiming device were significantly more accurate for both the ED and ND as compared to the punctures without aiming device (p < 0.001). The mean time required to complete the procedure, including image acquisition, trajectory planning, the placement of 10 needles, and the control-CT scan was 24.8 min without and 29.8 min with the aiming device.

CONCLUSION

The additional use of the aiming device in combination with the commercially available laser guidance system significantly increased the level of accuracy during this in vitro experiment compared to freehand passes.

Primary efficacy of percutaneous microwave ablation of malignant liver tumors: comparison of stereotactic and conventional manual guidance

In this study, we compare the primary efficacy of computed tomography-navigated stereotactic guidance to that of manual guidance for percutaneous microwave ablation of liver malignancies. In total, 221 patients (140, 17, and 64 with hepatocellular carcinoma, cholangiocellular carcinoma, and liver metastases, respectively) with 423 treated liver lesions underwent microwave ablation (MWA). Manual guidance (M) and stereotactic guidance (S) were used for 136 and 287 lesions, respectively. The primary endpoint was the primary efficacy and the secondary endpoint was the radiation dose. A generalised estimating equation was applied to analyse the correlation between the primary efficacy (lesion basis) and the type of guidance, size and location of lesion. The primary efficacy rate was significantly higher in the S-group (84.3%) than in the M-group (75.0%, p = 0.03). Lesion size > 30 mm was negatively correlated with the efficacy rate (odds ratio 0.38; 95% confidence interval 0.20–0.74). Stereotactic guidance was associated with a significantly lower dose length product (p < 0.01). In this retrospective study, percutaneous microwave ablation under stereotactic guidance exhibited significantly greater primary efficacy than conventional manual guidance.

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.

Intraoperative 2D C-arm and 3D O-arm in children: a comparative phantom study

PURPOSE

Exposure to ionizing radiation is a concern for children during intraoperative imaging. We aimed to assess the radiation exposure to the paediatric patient with 2D and 3D imaging.

METHODS

To evaluate the radiation exposure, patient absorbed doses to the organs were measured in an anthropomorphic phantom representing a five-year-old child, using thermoluminescent dosimeters. For comparative purposes, organ doses were measured using a C-arm for one minute of fluoroscopy and one acquisition with an O-arm. The cone-beam was centred on the pelvis. Direct and scattered irradiations were measured and compared (Student's t-test). Skin entrance dose rates were also evaluated.

RESULTS

All radiation doses were expressed in µGy. Direct radiation doses of pelvic organs were between 631.22 and 1691.87 for the O-arm and between 214.08 and 737.51 for the C-arm, and were not significant (p = 0.07). Close scattered radiation on abdominal organs were between 25.11 and 114.85 for the O-arm and between 8.03 and 55.34 for the C-arm, and were not significant (p = 0.07). Far scattered radiation doses on thorax, neck and head varied from 0.86 to 6.42 for the O-arm and from 0.04 to 3.08 for the C-arm, and were significant (p = 0.02). The dose rate at the skin entrance was 328.58 µGy.s^-1 for the O-arm and 1.90 with the C-arm.

CONCLUSION

During imaging of the pelvis, absorbed doses for a 3D O-arm acquisition were higher than with one minute fluoroscopy with the C-arm. Further clinical studies comparing effective doses are needed to assess ionizing risks of the intraoperative imaging systems in children.

[Diagnostics and treatment of osteoid osteoma]

BACKGROUND

Osteoid osteoma is the third most common benign bone tumor and typically induces pain that is worse at night.

OBJECTIVE

To identify the epidemiological, pathogenetic, histological and radiological characteristics of osteoid osteoma and to present the broad variety of treatment options.

MATERIAL AND METHODS

This review article summarizes relevant clinical studies and meta-analyses on this topic.

RESULTS

Osteoid osteoma is characterized by a central nidus smaller than 1.5 cm in diameter with surrounding bone sclerosis. In the majority of cases, the tumor occurs in the long bones of the lower extremities and is predominantly manifested in patients aged between 5 and 25 years. Pain is mediated by prostaglandins, which stimulate afferent peripheral nerve fibers. Besides plain radiographs, thin-section computed tomography represents the gold standard of diagnostics but should be complemented by magnetic resonance or nuclear medicine imaging modalities. The conservative treatment consists of long-term therapy with non-steroidal anti-inflammatory drugs. Minimally invasive radiofrequency ablation of the nidus is the current operative treatment of choice.

CONCLUSION

Success rates of radiofrequency ablation and other minimally invasive procedures are high while treatment costs and length of hospital stay are low. Thus, open surgical curettage is reserved for rare indications and en bloc excision of the nidus should only be performed in cases of recurrent lesions.

Evaluation of accuracy and precision of CT-guidance in Radiofrequency Ablation for osteoid osteoma in 86 patients

Background and purpose

Osteoid osteoma is a benign skeletal tumour that accounts for 2–3% of all bone tumours. The male-to-female ratio is around 4:1 and it predominates in children and young adults. The most common symptom is pain, frequently at night-time. Historically the main form of treatment has been surgical excision. With the development of Radiofrequency Ablation (RFA) there is a percutaneus alternative. Success rates of RFA are lower but the main advantage is the minimal invasive character of the therapy and the low complication rate. As a result of the minimal invasiveness the hospitalization- and rehabilitation periods are relatively short. However, in current literature no values for accuracy and precision are known for the CT-guided positioning.

Methods

Accuracy and precision of the needle position are determined for 86 procedures. Furthermore the population is divided into groups based on tumour diameter, location and procedure outcome.

Results

The clinical success rate was 81.4%. In 79% of procedures complete ablation was achieved. Accuracy was 2.84 mm on average, precision was 2.94 mm. Accuracy was significantly lower in more profound lesions. Accuracy in tibia and fibula was significantly higher compared to the femur. No significant difference was found between different tumour diameters.

Interpretation

The accuracy and precision found are considered good. Needle position is of major importance for procedure outcomes. The question however rises how the results of this therapy will turn out in treatment of larger tumours.

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

BACKGROUND

Radiofrequency (RF) ablation is the standard of care for the surgical treatment of non-spinal osteoid osteoma and has greatly reduced morbidity associated with surgical excision. Precise placement of the RF ablation probe is necessary to avoid incomplete ablation. Limiting radiation exposure is especially advantageous in the pediatric population in whom osteoid osteoma frequently occurs. The aim of this study was to compare the radiation dosimetry and clinical outcomes among patients treated with RF ablation using three different localization techniques.

METHODS

Case-control methods were used to analyze sixty-six cases. Patients were categorized into three treatment groups: (1) intraoperative three-dimensional cone-beam CT (computed tomography) imaging (O-Arm) with surgical navigation (StealthStation S7), (2) intraoperative three-dimensional imaging (O-Arm) only, and (3) radiology suite-based diagnostic CT imaging. Radiation dosimetry and clinical outcome were analyzed with use of the dose-length product and local-relapse-free survival, respectively.

RESULTS

Mean age was nineteen years for the twenty-three patients in group 1, twenty years for the seven patients in group 2, and nineteen years for the thirty-six patients in group 3. Mean follow-up was fifty-three months. The mean radiation dose for groups 1, 2, and 3 was 446.62, 379.78, and 1058.83 mGy-cm, respectively. Significant (p < 0.05) differences in the radiation dose existed between groups 1 and 3 and between groups 2 and 3, whereas no difference was found between groups 1 and 2. Local-remission-free survival at three years for groups 1, 2, and 3 was 84.7% (95% confidence interval [CI], 64.5% to 100%), 100% (95% CI, 100% to 100%), and 90.7% (95% CI, 80.7% to 100%), respectively. Fifty-eight (92%) of the sixty-three followed patients were asymptomatic at the latest follow-up visit.

CONCLUSIONS

RF ablation using intraoperative cone-beam CT imaging, with or without surgical navigation, was associated with a significantly lower radiation dose compared with ablation using a radiology suite-based CT technique. Ablation using each of the three imaging techniques was equally effective in treating osteoid osteomas with a similar risk of relapse.