Tag: Stereotactic techniques

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Feasibility and Accuracy of Robot-Assisted, Stereotactic Biopsy Using 3-Dimensional Intraoperative Imaging and Frameless Registration Tool

Neurosurgery 92:803–811, 2023

Robot-assisted stereotactic biopsy is evolving: 3-dimensional intraoperative imaging tools and new frameless registration systems are spreading.

OBJECTIVE: To investigate the accuracy and effectiveness of a new stereotactic biopsy procedure.

METHODS: Observational, retrospective analysis of consecutive robot-assisted stereotactic biopsies using the Neurolocate (Renishaw) frameless registration system and intraoperative O-Arm (Medtronic) performed at a single institution in adults (2019-2021) and comparisonwith a historical series from the same institution (2006-2016) not using the Neurolocate nor the O-Arm.

RESULTS: In 100 patients (55%men), 6.2 ± 2.5 (1-14) biopsy sampleswere obtained at 1.7 ± 0.7 (1-3) biopsy sites. An histomolecular diagnosis was obtained in 96% of cases. The mean duration of the procedure was 59.0 ± 22.3 min. Themean distance between the planned and the actual target was 0.7 ± 0.7 mm. On systematic postoperative computed tomography scans, a hemorrhage ≥10 mm was observed in 8 cases (8%) while pneumocephalus was distant from the biopsy site in 76%. A Karnofsky Performance Status score decrease ≥20 points postoperatively was observed in 4%. The average dose length product was 159.7 ± 63.4mGy cm. Compared with the historical neurosurgical procedure, this newprocedure had similar diagnostic yield (96 vs 98.7%; P = .111) and rate of postoperative disability (4.0 vs 4.2%, P = .914) but was shorter (57.8 ± 22.9 vs 77.8 ± 20.9 min; P < .001) despite older patients.

CONCLUSION: Robot-assisted stereotactic biopsy using the Neurolocate frameless registration system and intraoperative O-Arm is a safe and effective neurosurgical procedure. The accuracy of this robot-assisted surgery supports its effectiveness for daily use in stereotactic neurosurgery.

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Robot-Assisted Stereotactic Laser Ablation in Medically Intractable Epilepsy

Robot_Assisted_Stereotactic_Laser_Ablation_in

Operative Neurosurgery 10:167–173, 2014

Stereotactic laser ablation offers an advantage over open surgical procedures for treatment of epileptic foci, tumors, and other brain pathology. Robotassisted stereotactic laser ablation could offer an accurate, efficient, minimally invasive, and safe method for placement of an ablation catheter into the target.

OBJECTIVE: To determine the feasibility of placement of a stereotactic laser ablation catheter into a brain lesion with the use of robotic assistance, via a safe, accurate, efficient, and minimally invasive manner.

METHODS: A laser ablation catheter (Visualase, Inc) was placed by using robotic guidance (ROSA, Medtech Surgical, Inc) under general anesthesia into a localized epileptogenic periventricular heterotopic lesion in a 19-year-old woman with 10-year refractory focal seizure history. The laser applicator (1.65 mm diameter) position was confirmed by using magnetic resonance imaging (MRI). Ablation using the Visualase system was performed under multiplanar imaging with real-time thermal imaging and treatment estimates in each plane. A postablation MRI sequence (T1 postgadolinium contrast injection) was used to immediately confirm the ablation. RESULTS: MRI showed accurate skin entry point and trajectory, with the applicator advanced to the lesion’s distal boundary. Ablation was accomplished in less than 3 minutes of heating. The overall procedure, from time of skin incision to end of last ablation, was approximately 90 minutes. After confirmation of proper lesioning by using a T1 contrast-enhanced MRI, the applicator was removed, and the incision was closed using a single stitch. No hemorrhage or other untoward complication was visualized. The patient awoke without any complication, was observed overnight after admitting to a regular floor bed, and was discharged to home the following day.

CONCLUSION: This technique, using a combination of Visualase laser ablation, ROSA robot, and intraoperative MRI, facilitated a safe, efficacious, efficient, and minimally invasive approach that could be used for placement of 1 or multiple electrodes in the future.

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Brain Imaging in Chronic Epilepsy Patients After Depth Electrode (Stereoelectroencephalography) Implantation: Magnetic Resonance Imaging or Computed Tomography?

Depth electrode localization error

Neurosurgery 73:543–549, 2013

The accurate localization of depth electrodes in epilepsy surgery is important for correct interpretation of stereoelectroencephalography recordings and neurosurgical resection. Unfortunately, image quality in postimplantation magnetic resonance imaging (MRI) is degraded by metal artifacts. The registration of postimplantation computed tomography (CT) or MRI to preimplantation (artifact-free) MRI facilitates electrode imaging and optimal visualization of brain anatomy. However, registration errors negatively affect electrode localization accuracy.

OBJECTIVE: To compare the relative registration deviation between postimplantation CT and MRI with preimplantation MRI.

METHODS: Retrospectively, 14 pharmacoresistant epilepsy patients were included who underwent stereotactic insertion of multiple depth electrodes and preimplantation and postimplantation MRI and postimplantation CT. Postimplantation MRI and CT image sets were registered to preimplantation MRI. The registration error between the registered postimplantation MRI and CT was quantified by measuring the geometrical distance between the electrodes of the registered postimplantation CT and the postimplantation MRI.

RESULTS: The registration error of postimplantation imaging to preimplantation MRI was dependent on the algorithm used. After optimization, the smallest registration error was 1.22 6 0.29 mm (mean 6 SD) at the tip and 2.25 6 1.18 mm at the base of the electrode.

CONCLUSION: The good correspondence between the CT/MRI and the MRI/MRI registration suggests that either postimplantation MRI or CT is sufficient for accurate electrode localization. In case of postoperative morphological brain deformations, postimplantation MRI is still recommended.

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Accuracy of Postoperative Computed Tomography and Magnetic Resonance Image Fusion for Assessing Deep Brain Stimulation Electrodes

Neurosurgery 69:207–214, 2011 DOI: 10.1227/NEU.0b013e318218c7ae

Knowledge of the anatomic location of the deep brain stimulation (DBS) electrode in the brain is essential in quality control and judicious selection of stimulation parameters. Postoperative computed tomography (CT) imaging coregistered with preoperative magnetic resonance imaging (MRI) is commonly used to document the electrode location safely. The accuracy of this method, however, depends on many factors, including the quality of the source images, the area of signal artifact created by the DBS lead, and the fusion algorithm.

OBJECTIVE: To calculate the accuracy of determining the location of active contacts of the DBS electrode by coregistering postoperative CT image to intraoperative MRI.

METHODS: Intraoperative MRI with a surrogate marker (carbothane stylette) was digitally coregistered with postoperative CT with DBS electrodes in 8 consecutive patients. The location of the active contact of the DBS electrode was calculated in the stereotactic frame space, and the discrepancy between the 2 images was assessed.

RESULTS: The carbothane stylette significantly reduces the signal void on the MRI to a mean diameter of 1.4 6 0.1 mm. The discrepancy between the CT and MRI coregistration in assessing the active contact location of the DBS lead is 1.6 6 0.2 mm, P < .001 with iPlan (BrainLab AG, Erlangen, Germany) and 1.5 6 0.2 mm, P < .001 with Framelink (Medtronic, Minneapolis, Minnesota) software.

CONCLUSION: CT/MRI coregistration is an acceptable method of identifying the anatomic location of DBS electrode and active contacts.

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Development of Stereotactic Mass Spectrometry for Brain Tumor Surgery

Neurosurgery 68:280–290, 2011 DOI: 10.1227/NEU.0b013e3181ff9cbb

Surgery remains the first and most important treatment modality for the majority of solid tumors. Across a range of brain tumor types and grades, postoperative residual tumor has a great impact on prognosis. The principal challenge and objective of neurosurgical intervention is therefore to maximize tumor resection while minimizing the potential for neurological deficit by preserving critical tissue.

OBJECTIVE: To introduce the integration of desorption electrospray ionization mass spectrometry into surgery for in vivo molecular tissue characterization and intraoperative definition of tumor boundaries without systemic injection of contrast agents.

METHODS: Using a frameless stereotactic sampling approach and by integrating a 3-dimensional navigation system with an ultrasonic surgical probe, we obtained image-registered surgical specimens. The samples were analyzed with ambient desorption/ ionization mass spectrometry and validated against standard histopathology. This new approach will enable neurosurgeons to detect tumor infiltration of the normal brain intraoperatively with mass spectrometry and to obtain spatially resolved molecular tissue characterization without any exogenous agent and with high sensitivity and specificity.

RESULTS: Proof of concept is presented in using mass spectrometry intraoperatively for real-time measurement of molecular structure and using that tissue characterization method to detect tumor boundaries. Multiple sampling sites within the tumor mass were defined for a patient with a recurrent left frontal oligodendroglioma, World Health Organization grade II with chromosome 1p/19q codeletion, and mass spectrometry data indicated a correlation between lipid constitution and tumor cell prevalence.

CONCLUSION: The mass spectrometry measurements reflect a complex molecular structure and are integrated with frameless stereotaxy and imaging, providing 3-dimensional molecular imaging without systemic injection of any agents, which can be implemented for surgical margins delineation of any organ and with a rapidity that allows real-time analysis.

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