Stereotactic Device Research Articles

Principles of Stereotactic Surgery.

Stereotactic procedures are used to manage a diverse set of patients across a variety of clinical contexts. The stereotactic devices and software used in these procedures vary between surgeons, but the fundamental principles that constitute safe and accurate execution do not. The aim of this work is to describe these principles to equip readers with a generalizable knowledge base to execute and understand stereotactic procedures. A combination of a review of the literature and empirical experience from several experienced surgeons led to the creation of this work. Thus, this work is descriptive and qualitative by nature, and the literature is used to support instead of generate the ideas of this framework. The principles detailed in this work are categorized based on 5 clinical domains: imaging, registration, mechanical accuracy, target planning and adjustment, and trajectory planning and adjustment. Illustrations and tables are used throughout to convey the concepts in an efficient manner. Stereotactic procedures are complex, requiring a thorough understanding of each step of the workflow. The concepts described in this work enable functional neurosurgeons with the fundamental knowledge necessary to provide optimal patient care.

ARISE-The Accuracy Evaluation of a Patient-Specific 3D-Printed Biopsy System Based on MRI Data: A Cadaveric Study.

Brain biopsy is required for the accurate specification and further diagnosis of intracranial findings. The conventional stereotactic frames are used clinically for biopsies and offer the highest possible precision. Unfortunately, they come with some insurmountable technical and logistical limitations. The aim of the present work is to determine the clinical precision in the needle biopsy of the human brain using a new patient-specific stereotactic navigation device based on 3D printing. MRI data sets of human cadaver heads were used to plan 32 intracranial virtual biopsy targets located in different brain regions. Based on these data, 16 individualized stereotactic frames were 3D-printed. After the intraoperative application of the stereotactic device to the cadaver's head, the actual needle position was verified by postoperative CT. Thirty-two brain areas were successfully biopsied. The target point accuracy was 1.05 ± 0.63 mm, which represents the difference between the planned and real target points. The largest target point deviation was in the coronal plane at 0.60 mm; the smallest was in the transverse plane (0.45 mm). Three-dimensional-printed, personalized stereotactic frames or platforms are an alternative to the commonly used frame-based and frameless stereotactic systems. They are particularly advantageous in terms of accuracy, reduced medical imaging, and significantly simplified intraoperative handling.

A Prospective Trial of Single-Fraction Radiation to the Tumor Bed with a Novel Breast-Specific Stereotactic Radiation Therapy Device: The GammaPod

IntroductionRadiation therapy for early-stage breast cancer is typically delivered in a hypofractionated regimen to the whole breast followed by a tumor bed boost. This results in a treatment course of approximately 4 weeks. In this study, the tumor bed boost was delivered in a single fraction as part of a safety and feasibility study for FDA clearance of the device. Materials and MethodsEligible women with early-stage breast cancer underwent lumpectomy followed by radiation therapy. Patients underwent breast immobilization using a system specific for the GammaPod followed by CT simulation, boost treatment planning, and boost treatment delivery all in a single treatment day. Patients then started whole-breast radiation therapy within 1 week of the boost treatment. Patients and treatments were assessed for safety and feasibility. Acute toxicities were recorded. ResultsA single-fraction boost of 8 Gy was delivered to the tumor bed prior to a course of whole-breast radiation. The GammaPod treatment was successfully delivered in 14 of 17 enrolled patients. Acute toxicities from all radiation therapy, inclusive of the boost and whole-breast radiation, were limited to grade 1 events. ConclusionThe GammaPod device successfully delivered a single-fraction boost treatment to the tumor bed with no change in expected acute toxicities. The results of this study led to FDA clearance of the device through the Investigational Device Exemption process at the FDA. The GammaPod is in clinical use at 4 institutions nationally and internationally, with an additional sites pending in 2023.

Hemorrhagic complications during stereotactic biopsy of brain tumors

Relevance. Stereotactic biopsy (STB) is one of the main methods for diagnosing deep brain lesions. STB has several advantages over conventional intraoperative biopsy, as it is less traumatic and safer, especially for patients in critical condition. However, the most common complications of STB are hemorrhages, with a risk ranging from 0.9 % to 59.8 % depending on various studies. Intracranial hemorrhages are serious complications of surgical treatment of brain tumors, especially during biopsy using stereotactic techniques.Objective. To assess the risk of intracranial hemorrhages during STB of brain tumors and investigate possible factors influencing this risk, such as involvement of different brain regions in the neoplastic process, patient’s gender and age, degree of malignancy of the tumor, and use of different stereotactic devices.Materials and Methods. A retrospective study of data from 20 patients who underwent STB of brain tumors was conducted. Clinical data, examination results including coagulogram and aggregatogram, as well as data on involvement of different anatomical brain regions in the neoplastic process, degree of malignancy of the tumor, and use of a specific stereotactic device were analyzed.Results. Analysis of the frequency and structure of hemorrhagic complications of STB was performed, prognostic factors for high risk were identified, and preventive measures were proposed to reduce the number of hemorrhages.Conclusions. The introduction of the modern CRW Radionics stereotactic device into practice has reduced the frequency and severity of hemorrhagic complications after STB by two times. Lymphoproliferative processes and glioblastomas have a higher frequency of hemorrhages, but in most cases, they are clinically insignificant. There is a correlation between the degree of anaplasia of astrocytic tumors and the severity of hemorrhages. Ways to reduce the risks of intracranial hemorrhages during STB of brain tumors may include: careful preoperative planning of the biopsy trajectory; use of informative neurovisualization methods in planning the needle insertion trajectory; use of modern stereotactic systems by neurosurgeons who have undergone additional specialization and training on the specific device; use of modern biopsy needles. In addition, it is advisable to consider preoperative preventive hemostatic therapy in patients suspected of having a high degree of tumor anaplasia.

Dosimetric analysis of stereotactic radiosurgery planning techniques in different treatment devices in trigeminal nerve irradiation

This study aims to search for a cheaper and easily accessible alternative to Cyberknife, which is frequently used as a stereotactic radiosurgery device in the treatment of trigeminal neuralgia.Using tomography images of 20 trigeminal neuralgia patients treated with CyberKnife treatment devices, stereotactic planning techniques were applied retrospectively to the same patients on Tomotherapy and Versa HD treatment devices. Each patient was planned to receive a dose of 60 Gy in a single fraction.Treatment plans were evaluated in terms of the minimum, mean, and maximum doses received by the GTV in all three devices, as well as the percentage of the GTV volume that could receive 60 Gy. D98%, D90%, D50%, D30%, D10%, and conformity index (CI) and homogeneity index (HI) were also evaluated for GTV. The maximum doses of brainstem, D1%, D2%, D5%, and D10% were evaluated. Other critical organs: optic chiasm, optic nerves, cochlea's, eyes, and lenses were evaluated for their maximum dose. In addition, the volumes of 50% and 20% isodoses in healthy tissue were compared.While the Cyberknife device is superior in terms of brain stem doses, Versa HD device stands out in terms of maximum doses of optical structures.

A Novel Frameless Laser Stereotaxis System for Neurosurgical Interventions

The aim of the article is to introduce a novel laser-based frameless stereotactic device that can locate intracranial lesions quickly and with computed tomograph (CT)/magnetic resonance imaging (MRI) films. Preliminary experiences of application in 416 cases are also summarized. From August in 2020 to October in 2022, a total of 416 cases of new minimalist laser stereotactic surgery have been performed on 415 patients. Of the 415 patients, 377 had intracranial hematomas, while the remaining cases were brain tumors or brain abscesses. Postoperative CT was used to evaluate the accuracy of catheterization of 405 patients according to the MISTIE study. The duration time of locating was recorded. Rebleeding refers to the definition: Compared with preoperative CT, the relative volume of postoperative hematoma increases by >33% or absolute volume increase >12.5 mL. According to postoperative CT, the accuracy of 405 stereotactic catheterization cases was good in 346 cases (85.4%) and suboptimal in 59 cases (14.6%), with no poor results. Postoperative rebleeding occurred in 4 spontaneous cerebral hemorrhage cases and 1 brain biopsy case. The average localization time of supratentorial lesions was 13.2 minutes in the supine position, 21.5 minutes in the lateral position, and 27.6 minutes in the prone position. The new laser-based frameless stereotactic device is simple in principle and convenient in positioning operation of brain hematoma and abscess puncture, brain biopsy and tumor surgery, and appropriate to the precision requirements in most craniocerebral surgery.

Evaluation of a New CT-Guided Robotic System for Percutaneous Needle Insertion for Thermal Ablation of Liver Tumors: A Prospective Pilot Study

PurposeTo assess the feasibility and safety of a robotic system for percutaneous needle insertion during thermal ablation of liver tumors.Materials and MethodsThis study analyzed the CT-guided percutaneous needle insertion using the EPIONE robotic device (Quantum Surgical, Montpellier, France) for radiofrequency or microwave liver ablation. The main criteria of the study were feasibility (possibility to perform the thermal ablation after needle insertion), the number of needle adjustments (reiteration of robotically assisted needle insertion when initial needle positioning is considered insufficient to perform ablation), and robotic-guided procedure safety (complications related to the needle insertion). Patients were followed up at 6 months post-intervention to assess local tumor control.ResultsTwenty-one patients with 24 tumors, including 6 HCC and 18 metastases measuring 15.6 ± 7.2 mm, were enrolled. One patient (with one tumor) was excluded for protocol deviation. Robotic assisted thermal ablation was feasible for 22/23 lesions (95.7%) and 19/20 patients (95.0%), as validated by a data safety monitoring Board (95% CI [76.39%; 99.11%]) for the per-protocol population. The mean number of needle adjustments per tumor treated was 0.4 (SD: 0.7), with 70.8% of tumors requiring no adjustment. No adverse events were depicted. Rate of local tumor control was 83.3% for patients and 85.7% for tumors, at 6 months.ConclusionThis bicentric first-in-human pilot study suggests both feasibility and safety of a stereotactic CT-guided EPIONE device for the percutaneous needle insertion during liver tumor thermal ablation.

Development of an Animal Stereotactic Device for Preclinical Research on Tumor Response After Stereotactic Radiosurgery

In gamma knife radiosurgery, the tumor response to radiation is an important predictor of clinical treatment results. Since brain tumors have different characteristics and growth patterns, depending on the type, the tumors' response to radiation are also different. Compared with various other clinical treatments, there is a dearth of research on the development of gamma knife-magnetic resonance imaging (MRI) preclinical experimental equipment. Hence, the identification of preclinical equipment necessity for experimental animals will provide meaningful data for the provision of clinical assistance to humans. A device for stereotactic radiosurgery capable of MRI in small animals was developed. The feasibility of creating a preplan by means of small animal images was then assessed. A device for stereotaxic surgery of small animals using a 48-channel MRI coil was developed using a 3 dimensional printer. Rat brain-MRI images were obtained with a 3.0T MRI scanner using a multi-channel coil. The acquired MRI images were transferred to a GammaPlan workstation to establish a preplan. To gamma rays to the targeted site on animals, a positioning device combined with a G-frame was mounted on a gamma knife. Planning of radiosurgery based on MRI images became possible with GammaPlan workstations. Preclinical experiments using small animals are possible with the use of stereotactic devices. In clinical treatment, preclinical experimental results will provide meaningful information.

SEMI-AUTOMATIC MEASUREMENT OF INTIMA-MEDIA THICKNESS OF BRACHIAL ARTERY IN PATIENTS WITH CONGESTIVE HEART FAILURE

Objective: Cardiovascular diseases are associated with an increase in intima-media thickness (IMT). However, the techniques used to measure IMT have limitations. A semi-automatic device called UNEX has been developed, which overcomes the limitation of classic systems (in particular the investigator-dependency of conventional, “hand-held’’ measurements). The purpose of this study was to measure the intima-media thickness of the brachial artery (bIMT) with the UNEX device in patients with and without congestive heart failure. Design and method: The UNEX device is comprised of a 7.5-MHz, H-shaped linear array transducer and a novel stereotactic probe-holding device (UNEX EF 18G; UNEX Co., Nagoya, Japan). Another advantage of this device is the continuous recording of B-mode images and A-mode waves of the brachial artery. Measurement of bIMT was automatically performed on A-mode images of the far wall of the brachial artery. The analysis system automatically detects the measurement point where an image was clearly obtained. The average of mean measurement values obtained from 10 cardiac cycles was defined as bIMT. In a first set of clinical studies, we measured bIMT in patients with reduced left ventricular ejection fraction (HFrEF) and in patients without heart failure. Results: Patients with HFrEF (n = 85, ejection fraction: 38.3 ± 8.4 %, NT-pro-BNP: 713 ± 714.7 pg/ml) compared to patients without heart failure (n = 63) were older (66.4 ± 9.2 vs. 53.8 ± 12.6 years, p < 0.001), with more male subjects (67 vs. 40, p = 0.039). bIMT was higher in patients with HFrEF compared to the other group (0.295 ± 0.083 vs. 0.249 ± 0.083 mm, p < 0.001). After adjustment for age, gender and other cardiovascular risk factors, the result remained significant (p = 0.032). Conclusions: Our study demonstrate that IMT of large muscular arteries can be automatically (investigator independently) measured. Our data indicate an increased vascular remodeling in patients with HFrEF independent of other confounders.

Extracranial guiding structures for navigation to specific topographical sectors of the equine neopallium: an anatomical investigation performing three-dimensional distance measurements in adult warm-blooded horses.

This basically anatomical study focuses on two items; firstly, the establishment of a system for the cartographic subdivision of the neopallium; secondly, the topographical correlation of extracranial landmarks and intracranial sites on the neopallium. The surface of the neopallium was subdivided into 15 sectors with reference to a newly introduced pattern of Primary Sulci. The topographical link between extracranial landmarks and certain intracranial sites (i.e. neopallium sectors) was elaborated by using a simple stereotactic device and a computer-assisted measurement device. Measurements were performed between points on the head's outer surface and on the isolated brain. The introduction of an anatomical three-dimensional coordinate system was an essential key issue for this investigation. This setting facilitated the measurements and calculations of the so-called indirect distances that were characterised by their alignment along the three orthogonal axes (x, y, z) of the anatomical coordinate system. The inter-individual comparison (16 adult horses [Equus caballus]) of the indirect distances revealed that each sector centre lay within a distinct morphometric residence area. The measured and calculated data also showed that each sector centre could be assigned to its proper extracranial landmark that - in comparison with other landmarks - was best suited for the optimal allocation of the sector centre point.

Abstract P3-19-22: Clinical and cosmetic outcomes of adjuvant stereotactic partial breast irradiation using the GammaPod

Abstract Background: The GammaPod is the first stereotactic body radiation therapy (SBRT) system optimized for treating breast cancer. It is composed of the treatment delivery system, the stereotactic localization and immobilization device, prone patient loading system and a treatment planning system, streamlining radiation therapy for both patient and provider. The GammaPod allows for higher doses in one or several large fractions which differentiates SBRT from conventional techniques. Patients benefit from shorter treatment timelines and more precise targeting. This project investigated the clinical benefit of the GammaPod compared to accelerated partial breast irradiation (APBI) with external beam radiation. Methods: Consecutive patients from 2018-2021 were retrospectively reviewed. All patients were treated with a lumpectomy +/- sentinel lymph node biopsy followed by adjuvant GammaPod stereotactic partial breast irradiation. All patients had at least 1 month of follow up from SBRT completion. The treatment protocol included 30Gy delivered over 5 fractions. Patient, tumor, and dosimetric characteristics were analyzed. Toxicities and cosmesis were recorded prospectively by treating physicians and reviewed retrospectively. Local recurrence was defined as in-breast, or skin/chest wall; regional recurrence was defined as a nodal failure. Results: Forty-nine patients were included. One hundred percent were female and 78% were White. The median age was 63 years, AJCC 8th edition anatomic staging was predominantly stage 0 (29%) and stage 1 (69%), and median tumor size was 8mm. Fifty-five percent of patients were treated for left-sided disease. Seventy-one percent of lesions were invasive carcinomas; 97% were ER+/Her2- and one patient was Her2+. Twenty-nine percent had ductal carcinoma in situ. The most common GammaPod cup sizes were L00 (24%), L01 (16%), M00 (14%), L04 (8%), and L06 (8%). All patients received surgery prior to radiation therapy and the median days elapsed from surgery to radiation therapy was 53 days (34-272). One patient underwent adjuvant chemotherapy prior to radiation therapy for her2+ disease. Median total RT dose was 30Gy (27-43). All patients were treated in 5 fractions with a median beam time of 14.57 minutes and a median variation of 2.56 minutes between fractions. The median days elapsed in treatment was 10 days (4-20). Five patients were undergoing reirradiation. The median follow up time was 8.25 months (.9-27mo) and one patient had regional reoccurrence. Of the 41 patients with recorded cosmesis results, 98% experienced positive (excellent or good) cosmesis outcomes. Eighty-eight percent experienced excellent cosmesis at follow up and no patients experienced poor cosmesis. All recorded toxicities were grade 1 or less. Thirty-three percent of patients experienced blisters, 27% experienced some degree of hyperpigmentation/hypopigmentation, and 14% experienced contact dermatitis from the immobilization device. Other toxicities ≤ 6.1% included erythema, pain, desquamation, cellulitis/mastitis, and petechiae. Conclusion: We present an initial analysis of the novel GammaPod for SBRT adjuvant radiation treatment for early stage breast cancer. The use of the GammaPod yielded positive cosmesis results and was well tolerated with a minimal side effect profile compared to external beam APBI. Therefore, the GammaPod offers a promising alternative to external beam ABPI in terms of post radiation cosmesis and patient satisfaction. Citation Format: Kayla Paulosky, Sarah Ruff, Stewart J Becker, Mariana Guerrero, Sarah McAvoy, Elizabeth M Nichols. Clinical and cosmetic outcomes of adjuvant stereotactic partial breast irradiation using the GammaPod [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-19-22.

Early results of ultrasound-guided, vacuum-assisted breast biopsy for mammographic microcalcifications: combination with wire localization

Purpose: This study examined the usefulness of ultrasound-guided vacuum-assisted breast biopsy for mammographic microcalcification.Methods: case series from June- 2019 to June-2020 at Breast department Cho Ray hospital. The patients with BI-RADS Category 4 Mammographic microcalcification were included. Most microcalcifications were not observed on ultrasound. Sono-guided J-wire localization was first performed for the suspicious microcalcification area, and the location of the J-wire and calcification was determined with mammography in most cases. Sono-guided VABB was performed after removing the J-wire without a stereotactic device. On the other hand, Sono-guided VABB was performed directly without J-wire localization when microcalcification lesions were identified by mass on ultrasonography. In all cases, calcification was confirmed by specimen mammography and the pathology was performed. A follow-up examination was performed to confirm the presence of complications.Results: A total of 20 lesions of 18 patients with BI-RADS Category 4 Mammographic microcalcification were included. Mean age: 49,44 ± 9,49 (35-66). Mean size of lesions 10,83 ± 3,60 mm, (4-15mm). In 20 lesions, 6 lesions (30%) were diagnosed as a malignancy (2 cases of ductal carcinoma in situ, 3 cases of ductal carcinoma invasive, 1 case of atypical ductal hyperplasia). The remaining 14 lesions (70%) were diagnosed as benign (fibroadenoma: 4; fibrocystic exchange 7, fibrocystic desease: 1, typical hyperplasia : 2). There were no significant complications during follow up after VABB.Conclusion: Sono-guided VABB can be used effectively if combined with wire localization for microcalcification lesions.

Device for serial photography of the scalp

Serial photographic documentation of hair loss is essential to detect subtle changes and to make informed decisions on therapy. Hence, the need for an apparatus to comply with global photography is often required. We suggest an instrument design that captures images of the scalp with the head positioned in a stereotactic device.

Safety of direct injection of oligodendrocyte progenitor cells into the spinal cord of uninjured Göttingen minipigs.

This study was conducted as a final proof-of-safety direct injection of oligodendrocyte progenitor cells into the uninjured spinal cord prior to translation to the human clinical trials. In this study, 107 oligodendrocyte progenitor cells (LCTOPC1, also known as AST-OPC1 and GRNOPC1) in 50-μL suspension were injected directly into the uninjured spinal cords of 8 immunosuppressed Göttingen minipigs using a specially designed stereotactic delivery device. Four additional Göttingen minipigs were given Hanks' Balanced Salt Solution and acted as the control group. Cell survival and no evidence of histological damage, abnormal inflammation, microbiological or immunological abnormalities, tumor formation, or unexpected morbidity or mortality were demonstrated. These data strongly support the safety of intraparenchymal injection of LCTOPC1 into the spinal cord using a model anatomically similar to that of the human spinal cord. Furthermore, this research provides guidance for future clinical interventions, including mechanisms for precise positioning and anticipated volumes of biological payloads that can be safely delivered directly into uninjured portions of the spinal cord.

Simplified method for determining dose to a non-water phantom through the use of ND,w and IAEA TRS 483 for the GammaPod.

GammaPod, a breast stereotactic radiosurgery device, utilizes 25 rotating Co-60 sources to deliver highly conformal dose distributions. The GammaPod system requires that reference dosimetry be performed in a specific vendor-supplied poly-methylmethacrylate (PMMA) phantom. The nonstandard nature of GammaPod dosimetry, in both the phantom material and machine-specific reference (msr), prohibits use of the American Association of Physicists in Medicine Task Group 51 (TG-51) protocol. This study proposes a practical method using TRS 483 to make the reference dosimetry procedure simpler and to reduce overall uncertainties. The dose to PMMA (DPMMA) is determined under msr conditions using TRS 483 with an Exradin A1SL chamber placed in a PMMA phantom. The conversion factor, which converts from the dose-to-water (Dw) in broad-beam Co-60 reference geometry to DPMMA in the msr small field Co-60 (Qmsr) geometry, is derived using the Monte Carlo simulations and procedure described in TRS 483. The new conversion factor value for an Exradin A1SL chamber is 0.974. When combined with ND,w, DPMMA differs by 0.5% from the TG-21/Nx method and 0.2% from the IROC values. Uncertainty decreased from 2.2% to 1.6%. We successfully implemented TRS 483 reference dosimetry protocols utilizing ND,w for the GammaPod in the PMMA phantom. These results show not only agreement between measurements performed with the previously published method and independent thermoluminescent dosimetry measurements but also reductions in uncertainty. This also provides readers with a pathway to develop their own IAEA TRS 483 factor for any new small field machine that may be developed.

A novel laser-based stereotactic localization device for intracranial mass resection

Unfortunately, both frame-based and frameless stereotactic neuronavigation platforms are far from ubiquitous in global neurosurgery, and many facilities lack accurate localization technology to ensure the safety of intracranial surgery such as cerebral hemorrhage evacuation. Based on the principle of stereoscopic geometry, this paper introduces a novel method of intracranial lesion localization using translational and rotational lasers in an external Cartesian coordinate system.

A Stereotactic Device for Intraparenchymal Spinal Cord Injections: Latest Developments for Practical Clinical Use

This manuscript introduces the latest generation of a patient-mounted platform designed for segmental injections of therapeutics direct into the spinal cord parenchyma. It emphasizes its importance and it presents the rationale for developing this delivery methodology. It compares the newest with the previous generations, detailing how the modifications can streamline transportation, assembly, sterilization, and utilization of the platform by different surgeons. Finally, the illustrations depict the main alterations, as well as a cadaveric assessment of the device prototype in the cervical and thoracolumbar regions.

Reproducibility of a novel, vacuum-assisted immobilization for breast stereotactic radiotherapy.

A novel, breast‐specific stereotactic radiotherapy device has been developed for delivery of highly conformal, accelerated partial breast irradiation. This device employs a unique, vacuum‐assisted, breast cup immobilization system that applies a gentle, negative pressure to the target breast with the patient in the prone position. A device‐specific patient loader is utilized for simulation scanning and device docking. Prior to clinical activation, a prospective protocol enrolled 25 patients who had been or were to be treated with breast conservation surgery and adjuvant radiotherapy for localized breast cancer. The patients underwent breast cup placement and two separate CT simulation scans. Surgical clips within the breast were mapped and positions measured against the device’s integrated stereotactic fiducial/coordinate system to confirm reproducible and durable immobilization during the simulation, treatment planning, and delivery process for the device. Of the enrolled 25 patients, 16 were deemed eligible for analysis. Seventy‐three clips (median, 4; mean, 4.6; range, 1–8 per patient) were mapped in these selected patients on both the first and second CT scans. X, Y, and Z coordinates were determined for the center point of each clip. Length of vector change in position was determined for each clip between the two scans. The mean displacement of implanted clips was 1.90 mm (median, 1.47 mm; range, 0.44–6.52 mm) (95% CI, 1.6–2.20 mm). Additional analyses stratified clips by position within the breast and depth into the immobilization cup. Overall, this effort validated the clinically utilized 3‐mm planning target volume margin for accurate, reliable, and precise employment of the device.

Preclinical Evaluation of the Stealth Autoguide Robotic Guidance Device for Stereotactic Cranial Surgery: A Human Cadaveric Study

Introduction: Stereotactic procedures are routinely performed for brain biopsies, deep brain stimulation, and placement of stereoelectroencephalography (SEEG) electrodes for epilepsy. The recently developed Stealth Autoguide (Medtronic, Minneapolis, MN, USA) device does not require patients to don a stereotactic frame. In this preclinical study, we sought to quantitatively compare the Stealth Autoguide robotic system to 2 devices commonly used in clinical practice: the Navigus biopsy system (Medtronic) and the Leksell stereotactic frame (Elekta Ltd., Stockholm, Sweden). Methods: In the first experimental setup, we compared target accuracy of the Stealth Autoguide to the Navigus system by using phantom heads filled with gelatin to simulate the brain tissue. In the second experimental setup, we inserted SEEG electrodes to targets within cadaveric heads in a simulated operating room environment. Results: Using a homogeneous gelatin-filled phantom 3D reconstruction of a human head, we found that using the Stealth Autoguide system, while maintaining accuracy, was faster to use than the Navigus system. In our simulated operating room environment using nonliving human cadaveric heads, we found the accuracy of the Stealth Autoguide robotic device to be comparable to that of the Leksell frame. Discussion/Conclusion: These results compare the use of the Stealth Autoguide robotic guidance system with commonly used stereotactic devices, and this is the first study to compare its use and accuracy with the Leksell frame. These findings provide mounting evidence that Stealth Autoguide will have potential clinical uses in various stereotactic neurosurgical procedures.

A novel way of hook wire placement for surgical resection of suspicious breast lesions using the stereotactic vacuum assisted breast biopsy table.

Preoperative hook localization is a necessary procedure for targeting impalpable breast lesions. The aim of the current study is to introduce an alternative technique of wire placement by using the stereotactic biopsy device instead of the conventionally used mammography device. Fifty-one patients with impalpable mammographic lesions, graded BIRADS 4 or 5, were prospectively enrolled. Mean duration was 7±1.5minutes. Lesion-to-wire distance was <1cm in 96% (51/53). Hook wire placement using the stereotactic biopsy device is considered as a safe, accurate, fast, and well-tolerable for the patient procedure.