Robotic catheter ventriculostomy: feasibility, efficacy, and implications

Navigated bedside implantation of external ventricular drains with mobile health guidance: technical note and case series

PURPOSE

External ventricular drain (EVD) implantation is one of the fundamental procedures of emergency neurosurgery usually performed freehand at bedside or in the operating room using anatomical landmarks. However, this technique is frequently associated with malpositioning leading to complications or dysfunction. Here, we describe a novel navigated bedside EVD insertion technique, which is evaluated in a clinical case series with the aim of safety, accuracy, and efficiency in neurosurgical emergency settings.

METHODS

From 2021 to 2022, a mobile health-assisted navigation instrument (Thomale Guide, Christoph Miethke, Potsdam, Germany) was used alongside a battery-powered single-use drill (Phasor Health, Houston, USA) for bedside EVD placement in representative neurosurgical pathologies in emergency situations requiring ventricular cerebrospinal fluid (CSF) relief and intracranial pressure (ICP) monitoring.

RESULTS

In all 12 patients (8 female and 4 male), navigated bedside EVDs were placed around the foramen of Monro at the first ventriculostomy attempt. The most frequent indication was aneurysmal subarachnoid hemorrhage. Mean operating time was 25.8 ± 15.0 min. None of the EVDs had to be revised due to malpositioning or dysfunction. Two EVDs were converted into a ventriculoperitoneal shunt. Drainage volume was 41.3 ± 37.1 ml per day in mean. Mean length of stay of an EVD was 6.25 ± 2.8 days. Complications included one postoperative subdural hematoma and cerebrospinal fluid infection, respectively.

CONCLUSION

Combining a mobile health-assisted navigation instrument with a battery-powered drill and an appropriate ventricular catheter may enable and enhance safety, accuracy, and efficiency in bedside EVD implantation in various pathologies of emergency neurosurgery without adding relevant efforts.

Neuromate® robot-assisted ventricular catheter insertion

BACKGROUND AND IMPORTANCE

Insertion of ventricular catheters into small ventricles may require image guidance. Several options exist, including ultrasound guidance, frameless, and frame-based stereotactic approaches. There is no literature on management options when conventional image guidance fails to cannulate the ventricle. The accuracy of the robotic arm is well established in functional and epilepsy surgery. We report the first case using the Neuromate® robot for the placement of a shunt ventricular catheter into the lateral ventricle after a failed attempt with a more commonly used frameless electromagnetic navigation system.

CLINICAL PRESENTATION

A 30-year-old man had twice previously undergone foramen magnum decompression for a Chiari 1 malformation. He subsequently developed a significant cervical syrinx with clinical deterioration and a decision was made to place a ventriculoperitoneal shunt. As the ventricles were small, frameless electromagnetic navigation was used but the ventricle could not be cannulated. The Neuromate® robot was subsequently used to place the ventricular catheter successfully.

CONCLUSION

Neuromate® robot-assisted ventricular catheter placement may be considered when difficulty is experienced with more commonly used image guidance techniques.

Transfrontal External Ventricular Drainage Combined with OMMAYA Sac Implantation under Laser Navigation were Performed: A Technical Note

BACKGROUND

Hydrocephalus caused by spontaneous intracerebral hemorrhage (ICH) is an independent risk factor with adverse effects on the progression of the disease. Until now, the choice of intraventricular catheter placement and intraventricular fibrinolysis (IVF) has been mainly based on the personal experience of the neurosurgeon.

OBJECTIVE

We will introduce the clinical effect of the new external ventricular drainage (EVD), an independent innovation of our medical center, on ICH patients, hoping to inspire more neurosurgeons to apply our method.

METHODS

In this open retrospective study, We analyzed the clinical data, radiological manifestations, and prognostic scores of 10 patients with the spontaneous intracerebral hemorrhage who received transfrontal lateral ventricle puncture and drainage under laser navigation in our hospital.

RESULTS

A total of 10 patients with an average age of 58.10±9.97 years were enrolled for emergency surgery. All operations were completed according to the consensus specifications. It took 11.25±3.81 days for the intracranial pressure to return to normal. On admission, patients had a median GCS of 10. The median preoperative GCS was 8. The median GCS at discharge score was 15. At discharge, the median NIHSS score was 4. After 6 months of follow-up, patients had a median NIHSS score of 4. At discharge, the median ADL score of patients was 85. After 6 months of follow-up, the median ADL score of the patients was 95.

CONCLUSION

In treating patients with ICH, the emergency treatment of transfrontal external ventricular drainage combined with OMMAYA sac implantation under laser navigation is a surgical method worthy of further study.

Bullseye EVD: preclinical evaluation of an intra-procedural system to confirm external ventricular drainage catheter positioning

PURPOSE

External ventricular drainage (EVD) is a life-saving procedure indicated for elevated intracranial pressure. A catheter is inserted into the ventricles to drain cerebrospinal fluid and release the pressure on the brain. However, the standard freehand EVD technique results in catheter malpositioning in up to 60.1% of procedures. This proof-of-concept study aimed to evaluate the registration accuracy of a novel image-based verification system "Bullseye EVD" in a preclinical cadaveric model of catheter placement.

METHODS

Experimentation was performed on both sides of 3 cadaveric heads (n = 6). After a pre-interventional CT scan, a guidewire simulating the EVD catheter was inserted as in a clinical EVD procedure. 3D structured light images (Einscan, Shining 3D, China) were acquired of an optical tracker placed over the guidewire on the surface of the scalp, along with three distinct cranial regions (scalp, face, and ear). A computer vision algorithm was employed to determine the guidewire position based on the pre-interventional CT scan and the intra-procedural optical imaging. A post-interventional CT scan was used to validate the performance of the Bullseye optical imaging system in terms of trajectory and offset errors.

RESULTS

Optical images which combined facial features and exposed scalp within the surgical field resulted in the lowest trajectory and offset errors of 1.28° ± 0.38° and 0.33 ± 0.19 mm, respectively. Mean duration of the optical imaging procedure was 128 ± 35 s.

CONCLUSIONS

The Bullseye EVD system presents an accurate patient-specific method to verify freehand EVD positioning. Use of facial features was critical to registration accuracy. Workflow automation and development of a user interface must be considered for future clinical evaluation.

Frameless stereotactic brain biopsy and external ventricular drainage placement using the RONNA G4 system

Robot-assisted stereotactic procedures are among the latest technological improvements in neurosurgery. Herein, to the best of our knowledge, we report a first external ventricular drainage (EVD) placement using the RONNA G4 robotic system preformed together with brain biopsy, all in one procedure. A patient was presented with progressive drowsiness, cognitive slowing, poor mobility and incontinent. Magnetic resonance imaging brain scans revealed multicentric process located in the basal ganglia right with extensive vasogenic edema and dilatated ventricular system. Using the RONNAplan software two trajectories were planned: one for brain biopsy on the left side and one for EVD implantation on the right side; the procedures went without complications. The RONNA G4 robotic system is an accurate neurosurgical tool for performing frameless brain biopsies and EVD placement. Further studies are needed in order to enroll a larger patient sample and to calculate the possible placement deviation, and to perform the comparison with other robotic systems.

Robotic external ventricular drain placement for acute neurosurgical care in low-resource settings: feasibility considerations and a prototype design

OBJECTIVE

Emergency neurosurgical care in lower-middle-income countries faces pronounced shortages in neurosurgical personnel and infrastructure. In instances of traumatic brain injury (TBI), hydrocephalus, and subarachnoid hemorrhage, the timely placement of external ventricular drains (EVDs) strongly dictates prognosis and can provide necessary stabilization before transfer to a higher-level center of care that has access to neurosurgery. Accordingly, the authors have developed an inexpensive and portable robotic navigation tool to allow surgeons who do not have explicit neurosurgical training to place EVDs. In this article, the authors aimed to highlight income disparities in neurosurgical care, evaluate access to CT imaging around the world, and introduce a novel, inexpensive robotic navigation tool for EVD placement.

METHODS

By combining the worldwide distribution of neurosurgeons, CT scanners, and gross domestic product with the incidence of TBI, meningitis, and hydrocephalus, the authors identified regions and countries where development of an inexpensive, passive robotic navigation system would be most beneficial and feasible. A prototype of the robotic navigation system was constructed using encoders, 3D-printed components, machined parts, and a printed circuit board.

RESULTS

Global analysis showed Montenegro, Antigua and Barbuda, and Seychelles to be primary candidates for implementation and feasibility testing of the novel robotic navigation system. To validate the feasibility of the system for further development, its performance was analyzed through an accuracy study resulting in accuracy and repeatability within 1.53 ± 2.50 mm (mean ± 2 × SD, 95% CI).

CONCLUSIONS

By considering regions of the world that have a shortage of neurosurgeons and a high incidence of EVD placement, the authors were able to provide an analysis of where to prioritize the development of a robotic navigation system. Subsequently, a proof-of-principle prototype has been provided, with sufficient accuracy to target the ventricles for EVD placement.

Robot-guided Ventriculoperitoneal Shunt in Slit-like Ventricles

Background

Ventriculoperitoneal shunt (VPS) is the most common procedure used in the management of hydrocephalus regardless of the etiology. The standard free-hand technique is used for the placement of VPS in patients with enlarged ventricles. In patients with very small ventricles, CSF access through ventriculostomy becomes challenging and free-hand technique may be associated with high failure rates. In these situations, stereotactic-guided VPS becomes very useful.

Objective

To validate and describe the technique of robotic-guided VPS in cases with very small ventricles.

Methods

Three patients underwent VPS with robotic guidance between 2016 and 2019. One patient with a diagnosis of occipital meningocele, who later developed recalcitrant CSF leak from the operative site, and two other patients were diagnosed with idiopathic intracranial hypertension (IIH). Plain CT brain with 1-mm slice thickness acquired prior to the surgery was uploaded into the ROSA machine (Zimmer Biomet Warsaw, Indiana). The trajectory for the VPS is created on the robotic software presurgery. The patient is placed in the supine position with head turned to the side contralateral to VPS insertion and fixed with Mayfield clamp. Registration of the patient is done with the robot. The placement of the VPS is commenced with the robotic arm in the predetermined trajectory.

Results

Ventricle was hit in a single attempt in all the cases. CSF leak stopped in the case with meningocele; headache, and visual acuity improved in both the cases of IIH.

Conclusion

Robotic-guidance provides a safe and accurate method of VPS placement even in the presence of slit-like ventricles.

Neuronavigation-assisted bedside placement of bolt external ventricular drains in the intensive care setting: a technical note

BACKGROUND

The insertion of bolt external ventricular drains (EVD) on the intensive care unit (ICU) has enabled rapid cranial cerebrospinal fluid (CSF) diversion. However, bolt EVDs tend to be perceived as a more challenging technique, particularly when dealing with small ventricles or when there is midline shift distorting the ventricular morphology. Furthermore, if neuronavigation guidance is felt to be necessary, this usually assumes a transfer to an operating theatre. In this technical note, we describe the use of electromagnetic neuronavigation for bolt EVD insertion on the ICU and assess the protocol's feasibility and accuracy.

METHODS

Case series of neuronavigation-assisted bolt EVD insertion in ICU setting, using Medtronic Flat Emitter for StealthStation EM.

RESULTS

Neuronavigation-guided bolt EVDs were placed at the bedside in n = 5 patients on ICU. Their widest frontal ventricular horn diameter in the coronal plane ranged from 11 to 20 mm. No procedural complications were encountered. Post-procedural CT confirmed the optimal placement of the EVDs.

CONCLUSIONS

Electromagnetic neuronavigation is feasible at the ICU bedside and can assist the insertion of bolt EVDs in this setting. The preference for a bolt EVD to be inserted in ICU-as is standard practice at this unit-should not prohibit patients from benefitting from image guidance if required.

Freehand stereotactic ventricular catheter insertion for ventriculoperitoneal shunts based on individualized radio-anatomical landmarks

INTRODUCTION

The accurate placement of the ventricular catheter (VC) is critical in reducing the incidence of proximal failure of ventriculoperitoneal shunts (VPSs). The standard freehand technique is based on validated external anatomical landmarks but remains associated with a relatively high rate of VC malposition. Already proposed alternative methods have all their specific limitations. Herein, we evaluate the accuracy of our adapted freehand technique based on an individualized radio-anatomical approach. Reproducing the preoperative imaging on the patient's head using common anatomical landmarks allows to define stereotactic VC coordinates to be followed at surgery.

MATERIAL AND METHODS

Fifty-five consecutive patients treated with 56 VPS between 11/2005 and 02/2020 fulfilled the inclusion criteria of this retrospective study. Burr hole coordinates, VC trajectory, and length were determined in all cases on preoperative computed tomography (CT) scan and were accurately reported on patients' head. The primary endpoint was to evaluate VC placement accuracy. The secondary endpoint was to evaluate the rate and nature of postoperative VC-related complications.

RESULTS

Our new technique was applicable in all patients and no VC-related complications were observed. Postoperative imaging showed VC optimally placed in 85.7% and sub-optimally placed in 14.3% of cases. In all procedures, all the holes on the VC tip were found in the ventricular system.

CONCLUSIONS

This simple individualized technique improves the freehand VC placement in VPS surgery, making its accuracy comparable to that of more sophisticated and expensive techniques. Further randomized controlled studies are required to compare our results with those of the other available techniques.

Free-hand stereotactic ventricular catheter insertion technique based on radio-anatomical landmarks. How I do it

BACKGROUND

Accurate ventricular catheter (VC) placement plays an important role in reducing the risk of ventriculoperitoneal shunt failure. Free-hand VC insertion is associated with a significant misplacement rate. Consequently, several expensive alternative methods that are unfortunately not available worldwide have been used. To overcome these limitations, we developed a simple surgical technique based on radio-anatomical landmarks aimed at reducing VC's misplacements.

METHOD

We reproduce the preoperative imaging on the patient's head using common anatomical landmarks. This allows defining stereotactic VC coordinates to be followed during the surgical procedure.

CONCLUSION

This simple and cost-effective method improves VC insertion accuracy.

Utility of image-guided external ventriculostomy: analysis of contemporary practice in the United Kingdom and Ireland

OBJECTIVE

Freehand external ventricular drain (EVD) insertion is associated with a high rate of catheter misplacement. Image-guided EVD placement with neuronavigation or ultrasound has been proposed as a safer, more accurate alternative with potential to facilitate proper placement and reduce catheter malfunction risk. This study aimed to determine the impact of image-guided EVD placement on catheter tip position and drain functionality.

METHODS

This study is a secondary analysis of a data set from a prospective, multicenter study. Data were collated for EVD placements undertaken in the United Kingdom and Ireland from November 2014 to April 2015. In total, 21 large tertiary care academic medical centers were included.

RESULTS

Over the study period, 632 EVDs were inserted and 65.9% had tips lying free-floating in the CSF. Only 19.6% of insertions took place under image guidance. The use of image guidance did not significantly improve the position of the catheter tip on postoperative imaging, even when stratified by ventricular size. There was also no association between navigation use and drain blockage.

CONCLUSIONS

Image-guided EVD placement was not associated with an increased likelihood of achieving optimal catheter position or with a lower rate of catheter blockage. Educational efforts should aim to enhance surgeons' ability to apply the technique correctly in cases of disturbed cerebral anatomy or small ventricles to reduce procedural risks and facilitate effective catheter positioning.

Optimizing accuracy of freehand cannulation of the ipsilateral ventricle for intracranial pressure monitoring in patients with brain trauma

Background

Intracranial pressure (ICP) monitoring in traumatic brain injury (TBI) usually requires the placement of a catheter into the ipsilateral ventricle. This surgical procedure is commonly performed via a freehand method using surface anatomical landmarks as guides. The current accuracy of the catheter placement remains relatively low and even lower among TBI patients. This study was undertaken to optimize the freehand ventricular cannulation to increase the accuracy for TBI. The authors hypothesized that an optimal surgical plan of cannulation should give an operator the greatest degrees of freedom, which could be measured as the range of operation angle, range of catheter placement depth, and size of the target area.

Methods

An imaging simulation was first performed using the computed tomography (CT) images of 47 adult patients with normal brain anatomy. On the reconstructed 3D head model, four different coronal planes of ventricular cannulation were identified: a 4-cm anterior, a 2-cm anterior, a standard (central), and a 2-cm posterior plane. The degrees of freedom during the cannulation procedure were determined, including the relevant angles, lengths of cannulation, cross-sectional area, and bounding rectangle of the lateral ventricle. Next, a retrospective assessment was performed on the CT scans of another 111 patients with TBI who underwent freehand ventricular cannulation for ICP monitoring. Postoperative measurements were also performed based on CT images to calculate the accuracy and safety of catheter placement between coronal planes in practice.

Results

Our simulation results showed that the 2-cm anterior plane had more extensive degrees of freedom for ventricular cannulation, in terms of length of catheter trajectory (7% longer, P<0.001), cross-sectional area of the lateral ventricle (14% larger, P=0.046), and length of the lateral ventricle (17% wider, P<0.001) than that of the standard plane, while both the 4-cm anterior and 2-cm posterior planes did not offer advantages over the standard plane in these ways. The mean length range of catheter trajectory in the 2-cm anterior plane was 41 to 58 mm. Retrospective assessment of TBI patients with ICP monitor placement also confirmed our simulation data. It showed that the accuracy of ipsilateral ventricle cannulation in the 2-cm anterior plane was 70.6%, which was a significant increase from 42.9% in the standard plane (P=0.007).

Conclusions

Our imaging simulation and retrospective study demonstrate that different coronal planes could provide different degrees of freedom for cannulation, the 2-cm anterior plane has the greatest degrees of freedom in terms of larger target area and greater length range of the trajectory. The optimized surgical plan in this manner could improve cannulation accuracy and benefit a significant number of TBI patients.

sEVD-smartphone-navigated placement of external ventricular drains

BACKGROUND

Currently, the trajectory for insertion of an external ventricular drain (EVD) is mainly determined using anatomical landmarks. However, non-assisted implantations frequently require multiple attempts and are associated with EVD malpositioning and complications. The authors evaluated the feasibility and accuracy of a novel smartphone-guided, angle-adjusted technique for assisted implantations of an EVD (sEVD) in both a human artificial head model and a cadaveric head.

METHODS

After computed tomography (CT), optimal insertion angles and lengths of intracranial trajectories of the EVDs were determined. A smartphone was calibrated to the mid-cranial sagittal line. Twenty EVDs were placed using both the premeasured data and smartphone-adjusted insertion angles, targeting the center of the ipsilateral ventricular frontal horn. The EVD positions were verified with post-interventional CT.

RESULTS

All 20 sEVDs (head model, 8/20; cadaveric head, 12/20) showed accurate placement in the ipsilateral ventricle. The sEVD tip locations showed a mean target deviation of 1.73° corresponding to 12 mm in the plastic head model, and 3.45° corresponding to 33 mm in the cadaveric head. The mean duration of preoperative measurements on CT data was 3 min, whereas sterile packing, smartphone calibration, drilling, and implantation required 9 min on average.

CONCLUSIONS

By implementation of an innovative navigation technique, a conventional smartphone was used as a protractor for the insertion of EVDs. Our ex vivo data suggest that smartphone-guided EVD placement offers a precise, rapidly applicable, and patient-individualized freehand technique based on a standard procedure with a simple, cheap, and widely available multifunctional device.

Robotic Stereotaxy in Cranial Neurosurgery: A Qualitative Systematic Review

BACKGROUND

Modern-day stereotactic techniques have evolved to tackle the neurosurgical challenge of accurately and reproducibly accessing specific brain targets. Neurosurgical advances have been made in synergy with sophisticated technological developments and engineering innovations such as automated robotic platforms. Robotic systems offer a unique combination of dexterity, durability, indefatigability, and precision.

OBJECTIVE

To perform a systematic review of robotic integration for cranial stereotactic guidance in neurosurgery. Specifically, we comprehensively analyze the strengths and weaknesses of a spectrum of robotic technologies, past and present, including details pertaining to each system's kinematic specifications and targeting accuracy profiles.

METHODS

Eligible articles on human clinical applications of cranial robotic-guided stereotactic systems between 1985 and 2017 were extracted from several electronic databases, with a focus on stereotactic biopsy procedures, stereoelectroencephalography, and deep brain stimulation electrode insertion.

RESULTS

Cranial robotic stereotactic systems feature serial or parallel architectures with 4 to 7 degrees of freedom, and frame-based or frameless registration. Indications for robotic assistance are diversifying, and include stereotactic biopsy, deep brain stimulation and stereoelectroencephalography electrode placement, ventriculostomy, and ablation procedures. Complication rates are low, and mainly consist of hemorrhage. Newer systems benefit from increasing targeting accuracy, intraoperative imaging ability, improved safety profiles, and reduced operating times.

CONCLUSION

We highlight emerging future directions pertaining to the integration of robotic technologies into future neurosurgical procedures. Notably, a trend toward miniaturization, cost-effectiveness, frameless registration, and increasing safety and accuracy characterize successful stereotactic robotic technologies.

Utilizing preprocedural CT scans to identify patients at risk for suboptimal external ventricular drain placement with the freehand insertion technique

OBJECTIVE

Freehand insertion of external ventricular drains (EVDs) using anatomical landmarks is considered the primary method for placement, although alternative techniques have shown improved accuracy in positioning. The purpose of this study was to retrospectively evaluate which features of the baseline clinical history and preprocedural CT scan predict EVD positioning into suboptimal and unsatisfactory locations when using the freehand insertion technique.

METHODS

A retrospective chart review was performed evaluating 189 consecutive adult patients who received an EVD via freehand technique through an anterior burr hole between January 1, 2014, and December 31, 2015, at a Level 1 trauma facility in Edmonton, Alberta, Canada. The primary outcome measures included features associated with suboptimal positioning (Kakarla grade 1 vs Kakarla grades 2 and 3). The secondary outcome measures were features associated with unsatisfactory positioning (Kakarla grades 1 and 2 vs Kakarla grade 3).

RESULTS

Fifty-one EVDs (27%) were suboptimally positioned. Fifteen (8%) EVDs were placed into eloquent cortex or nontarget CSF spaces. Admitting diagnosis, head height-to-width ratio in axial plane, and side of predominant pathology were found to be significantly associated with suboptimal placement (p = 0.02, 0.012, and 0.02, respectively). A decreased height-to-width ratio was also associated with placement into only eloquent cortex and/or nontarget CSF spaces (p = 0.003).

CONCLUSIONS

Freehand insertion of an EVD is associated with significant suboptimal positioning into parenchyma and nontarget CSF spaces. The likelihood of inaccurate EVD placement can be predicted with baseline clinical and radiographic features. The patient's height-to-width ratio represents a novel potential radiographic predictor for malpositioning.

Revisiting the rules for freehand ventriculostomy: a virtual reality analysis

OBJECTIVE Frontal ventriculostomy is one of the most frequent and standardized procedures in neurosurgery. However, many first and subsequent punctures miss the target, and suboptimal placement or misplacement of the catheter is common. The authors therefore reexamined the landmarks and rules to determine the entry point and trajectory with the best hit rate (HtR). METHODS The authors randomly selected CT scans from their institution's DICOM pool that had been obtained in 50 patients with normal ventricular and skull anatomy and without ventricular puncture. Using a 5 × 5-cm frontal grid with 25 entry points referenced to the bregma, the authors examined trajectories 1) perpendicular to the skull, 2) toward classic facial landmarks in the coronal and sagittal planes, and 3) toward an idealized target in the middle of the ipsilateral anterior horn (ILAH). Three-dimensional virtual reality ventriculostomies were simulated for these entry points; trajectories and the HtRs were recorded, resulting in an investigation of 8000 different virtual procedures. RESULTS The best HtR for the ILAH was 86% for an ideal trajectory, 84% for a landmark trajectory, and 83% for a 90° trajectory, but only at specific entry points. The highest HtRs were found for entry points 3 or 4 cm lateral to the midline, but only in combination with a trajectory toward the contralateral canthus; and 1 or 2 cm lateral to the midline, but only paired with a trajectory toward the nasion. The same "pairing" exists for entry points and trajectories in the sagittal plane. For perpendicular (90°) trajectories, the best entry points were at 3-5 cm lateral to the midline and 3 cm anterior to the bregma, or 4 cm lateral to the midline and 2 cm anterior to the bregma. CONCLUSIONS Only a few entry points offer a chance of a greater than 80% rate of hitting the ILAH, and then only in combination with a specific trajectory. This "pairing" between entry point and trajectory was found both for landmark targeting and for perpendicular trajectories, with very limited variability. Surprisingly, the ipsilateral medial canthus, a commonly reported landmark, had low HtRs, and should not be recommended as a trajectory target.

A novel miniature robotic guidance device for stereotactic neurosurgical interventions: preliminary experience with the iSYS1 robot

OBJECTIVE

Robotic devices have recently been introduced in stereotactic neurosurgery in order to overcome the limitations of frame-based and frameless techniques in terms of accuracy and safety. The aim of this study is to evaluate the feasibility and accuracy of the novel, miniature, iSYS1 robotic guidance device in stereotactic neurosurgery.

METHODS

A preclinical phantom trial was conducted to compare the accuracy and duration of needle positioning between the robotic and manual technique in 162 cadaver biopsies. Second, 25 consecutive cases of tumor biopsies and intracranial catheter placements were performed with robotic guidance to evaluate the feasibility, accuracy, and duration of system setup and application in a clinical setting.

RESULTS

The preclinical phantom trial revealed a mean target error of 0.6 mm (range 0.1–0.9 mm) for robotic guidance versus 1.2 mm (range 0.1–2.6 mm) for manual positioning of the biopsy needle (p < 0.001). The mean duration was 2.6 minutes (range 1.3–5.5 minutes) with robotic guidance versus 3.7 minutes (range 2.0–10.5 minutes) with manual positioning (p < 0.001). Clinical application of the iSYS1 robotic guidance device was feasible in all but 1 case. The median real target error was 1.3 mm (range 0.2–2.6 mm) at entry and 0.9 mm (range 0.0–3.1 mm) at the target point. The median setup and instrument positioning times were 11.8 minutes (range 4.2–26.7 minutes) and 4.9 minutes (range 3.1–14.0 minutes), respectively.

CONCLUSIONS

According to the preclinical data, application of the iSYS1 robot can significantly improve accuracy and reduce instrument positioning time. During clinical application, the robot proved its high accuracy, short setup time, and short instrument positioning time, as well as demonstrating a short learning curve.

Shunt Surgery in Idiopathic Intracranial Hypertension Aided by Electromagnetic Navigation

BACKGROUND

Idiopathic intracranial hypertension (IIH) is characterized by increased cerebrospinal fluid (CSF) pressure and normal or slit ventricles. Lumboperitoneal shunting had been favored by many investigators for CSF diversion in IIH for decades; however, it has been associated with various side effects. Because of the small ventricular size adequate positioning of a ventricular catheter is challenging.

OBJECTIVES

Here, we investigated the usefulness of electromagnetic (EM)-guided ventricular catheter placement for ventriculoperitoneal shunting in IIH.

METHODS

Eighteen patients with IIH were included in this study. The age of patients ranged from 5 to 58 years at the time of surgery (mean age: 31.8 years; median: 29 years). There were 2 children (5 and 11 years old) and 16 adults. Inclusion criteria for the study were an established clinical diagnosis of IIH, lack of improvement with medication, and the presence of small ventricles. In all patients EM-navigated placement of the ventricular catheter was performed using real-time tracking of the catheter tip for exact positioning close to the foramen of Monro. Postoperative CT scans were correlated with intraoperative screen shots to validate the position of the catheter.

RESULTS

In all patients EM-navigated ventricular catheter placement was achieved with a single pass. There were no intraoperative or postoperative complications. Postoperative imaging confirmed satisfactory positioning of the ventricular catheter. No proximal shunt failure was observed during the follow-up at a mean of 41.5 months (range: 7-90 months, median: 40.5 months).

CONCLUSIONS

EM-navigated ventricular catheter placement in shunting for IIH is a safe and straightforward technique. It obviates the need for sharp head fixation, the head of the patient can be moved during surgery, and it may reduce the revision rate during follow-up.

Recent technological advances in pediatric brain tumor surgery

X-rays and ventriculograms were the first imaging modalities used to localize intracranial lesions including brain tumors as far back as the 1880s. Subsequent advances in preoperative radiological localization included computed tomography (CT; 1971) and MRI (1977). Since then, other imaging modalities have been developed for clinical application although none as pivotal as CT and MRI. Intraoperative technological advances include the microscope, which has allowed precise surgery under magnification and improved lighting, and the endoscope, which has improved the treatment of hydrocephalus and allowed biopsy and complete resection of intraventricular, pituitary and pineal region tumors through a minimally invasive approach. Neuronavigation, intraoperative MRI, CT and ultrasound have increased the ability of the neurosurgeon to perform safe and maximal tumor resection. This may be facilitated by the use of fluorescing agents, which help define the tumor margin, and intraoperative neurophysiological monitoring, which helps identify and protect eloquent brain.

Design Optimization of a Magnetic Field-Based Localization Device for Enhanced Ventriculostomy

The accuracy of many freehand medical procedures can be improved with assistance from real-time localization. Magnetic localization systems based on harnessing passive permanent magnets (PMs) are of great interest to track objects inside the body because they do not require a powered source and provide noncontact sensing without the need for line-of-sight. While the effect of the number of sensors on the localization accuracy in such systems has been reported, the spatial design of the sensing assembly is an open problem. This paper presents a systematic approach to determine an optimal spatial sensor configuration for localizing a PM during a medical procedure. Two alternative approaches were explored and compared through numerical simulations and experimental investigation: one based on traditional grid configuration and the other derived using genetic algorithms (GAs). Our results strongly suggest that optimizing the spatial arrangement has a larger influence on localization performance than increasing the number of sensors in the assembly. We found that among all the optimization schemes, the approach utilizing GA produced sensor designs with the smallest localization errors.

Ultrasound stylet for non-image-guided ventricular catheterization

OBJECT Urgent ventriculostomy placement can be a lifesaving procedure in the setting of hydrocephalus or elevated intracranial pressure. While external ventricular drain (EVD) insertion is common, there remains a high rate of suboptimal drain placement. Here, the authors seek to demonstrate the feasibility of an ultrasound-based guidance system that can be inserted into an existing EVD catheter to provide a linear ultrasound trace that guides the user toward the ventricle. METHODS The ultrasound stylet was constructed as a thin metal tube, with dimensions equivalent to standard catheter stylets, bearing a single-element, ceramic ultrasound transducer at the tip. Ultrasound backscatter signals from the porcine ventricle were processed by custom electronics to offer real-time information about ventricular location relative to the catheter. Data collected from the prototype device were compared with reference measurements obtained using standard clinical ultrasound imaging. RESULTS A study of porcine ventricular catheterization using the experimental device yielded a high rate of successful catheter placement after a single pass (10 of 12 trials), despite the small size of pig ventricles and the lack of prior instruction on porcine ventricular architecture. A characteristic double-peak signal was identified, which originated from ultrasound reflections off of the near and far ventricular walls. Ventricular dimensions, as obtained from the width between peaks, were in agreement with standard ultrasound reference measurements (p < 0.05). Furthermore, linear ultrasound backscatter data permitted in situ measurement of the stylet distance to the ventricular wall (p < 0.05), which assisted in catheter guidance. CONCLUSIONS The authors have demonstrated the ability of the prototype ultrasound stylet to guide ventricular access in the porcine brain. The alternative design of the device makes it potentially easy to integrate into the standard workflow for bedside EVD placement. The availability of a fast, easy-to-use, inexpensive guidance system can play a role in reducing the complication rate for EVD placement.

Guided (VENTRI-GUIDE) versus freehand ventriculostomy: study protocol for a randomized controlled trial

BACKGROUND

Despite the widespread use of external ventricular drainage, revision rates, and associated complications are reported between 10 and 40%. Current available image-guided techniques using stereotaxy, endoscopy, or ultrasound for catheter placements remain time-consuming techniques. Recently, a smartphone-assisted guide with high precision has been described. The development of an easy-to-use, portable, image-guided system could reduce the need for multiple passes and improve the rate of accurate catheter placement. This study aims to prospectively compare in a randomized controlled manner the accuracy of the freehand pass technique versus an easy-to-use, portable, adjustable guiding device for ventriculostomy catheter placement.

METHODS/DESIGN

This is a single center, prospective, randomized trial with a blinded endpoint (ventricular catheter tip location) assessment. Adult patients with the indication for ventriculostomy, as proven by computed tomography (CT), will be randomly assigned to the treatment group or the control group. For patients in the treatment group, ventriculostomy will be performed using an adjustable guiding device and DICOM (Digital Imaging and Communications in Medicine) image-reading software assistance (for example, using a mini-tablet) based on preoperative CT imaging.Patients in the control group will receive standard freehand ventriculostomy using anatomical landmarks. The catheter may be placed for external drainage or internal (ventriculoperitoneal) shunting in both groups. The primary outcome measure is the rate of correct placements of the ventricular catheter, defined as a score of 1 to 3 on grading system for catheter tip location on a postoperative CT scan. Participants will be followed for the duration of hospital stay, an expected average of two weeks. The primary outcome will be determined by one of the authors blinded to the treatment allocation. We aim to include 236 patients in three years. Secondary outcome measures include: frequency of placements required, frequency of completed placements within the ventricle of the perforated part of the catheter tip, frequency of very early and early shunt failures (revision of the ventricular drainage within 24 hours and within the hospital stay), frequency and percentage of complications (procedure-related and nonsurgical) at discharge.

DISCUSSION

This is the study design of a single center, prospective, randomized controlled trial to investigate whether guided ventriculostomy is superior to the standard freehand technique. One strength of this study is the prospective, randomized, interventional type of study testing a new easy-to-handle guided versus freehand ventricular catheter placement. A second strength of this study is that the power calculation is based on catheter accuracy using an available grading system for catheter tip location, and is calculated with the use of recent study results of our own population, supported by data from prominent studies.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT02048553 (registered on 28 January 2014).

Factors associated with external ventricular drain placement accuracy: data from an electronic health record repository

BACKGROUND

We evaluated external ventricular drain placement for factors associated with placement accuracy. Data were acquired using an electronic health record data requisition tool.

METHOD

Medical records of all patients who underwent ventriculostomy from 2003 to 2010 were identified and evaluated. Patient demographics, diagnosis, type of guidance and number of catheter passes were searched for and recorded. Post-procedural hemorrhage and/or infection were identified. A grading scale was used to classify accuracy of catheter placements. A multiple logistic regression model was developed to assess features associated with accurate catheter placement.

RESULTS

One hundred nine patients who underwent 111 ventriculostomies from 2003 to 2010 were identified. Patient diagnoses were classified into vascular (63 %), tumor (21 %), trauma (14 %), and cyst (2 %). Procedures were performed freehand in 90 (81 %), with the Ghajar guide in 17 (15 %), and with image guidance in 4 (4 %) patients. Eighty-eight (79 %) catheters were placed in the correct location. Trauma patients were more likely to have catheters misplaced (p = 0.007) whereas patients in other diagnostic categories were not significantly associated with misplaced catheters. Post-procedural hemorrhage was noted in 2 (1.8 %) patients on post-procedural imaging studies. Five (4.5 %) definite and 6 (5.4 %) suspected infections were identified.

CONCLUSIONS

External ventricular drain placement can be performed accurately in most patients. Patients with trauma are more likely to have catheters misplaced. Further development is required to identify and evaluate procedure outcomes using an electronic health record repository.

Strategic placement of bedside ventriculostomies using ultrasound image guidance: report of three cases

BACKGROUND

The blind free-hand technique for external ventricular drain (EVD) placement sometimes requires multiple attempts, and catheter location is often less than ideal. Our institution has adapted an intraoperative ultrasound-guided ventriculostomy technique for the placement of EVDs at the bedside. Our experience with ultrasound at the bedside has proven to be invaluable in certain circumstances. We present three cases of strategic EVD catheter trajectories that were made possible at the bedside with the use of ultrasound.

METHODS

Illustrative cases were chosen from a larger prospective study investigating the ultrasound-guided EVD technique. A portable ultrasound with a "burr hole" probe was used with modification of the standard surgical technique for placement of EVDs at the bedside.

RESULTS

Case 1 describes an unexpected re-hemorrhage that was first realized by the ultrasound image obtained during the bedside EVD placement procedure. The catheter was purposefully directed across midline to the more prominent ventricle on the contralateral side based on this real-time finding. Case 2 describes how ultrasound was used to salvage the failed free-hand procedure and cannulate an extremely small ventricular space at the bedside. Case 3 describes an unconventionally placed burr hole that provided a customized trajectory in which the EVD catheter was placed just laterally and inferior to a large frontal hematoma.

CONCLUSION

Ultrasound-guided bedside EVD placement allows EVD trajectories to be customized based on real-time information to accommodate for distorted and dynamic anatomy of the brain and its ventricles.

Smartphone-assisted guide for the placement of ventricular catheters

OBJECTIVE

Freehand placement of ventricular catheters (VC) is reported to be inaccurate in 10-40 %. Endoscopy, ultrasound, or neuronavigation are used in selected cases with significant technical and time-consuming efforts. We suggest a smartphone-assisted guiding tool for the placement of VC.

METHODS

Measurements of relevant parameters in 3D-MRI datasets in a patient cohort with narrow ventricles for a frontal precoronal VC placement were performed. In this context, a guiding tool was developed to apply the respective measures for VC placement. The guiding tool was tested in a phantom followed by CT imaging to quantify placement precision. A smartphone application was designed to assist the relevant measurements. The guide was applied in 35 patients for VC placement.

RESULTS

MRI measurements revealed the rectangular approach in the sagittal plane and the individual angle towards the tangent in the coronal section as relevant parameter for a frontal approach. The latter angle ranged from medial (91.96° ± 2.75°) to lateral margins (99.56° ± 4.14°) of the ventricle, which was similar in laterally shifted (±5 mm) entry points. The subsequently developed guiding tool revealed precision measurements in an agarose model with 1.1° ± 0.7° angle deviation. Using the smartphone-assisted guide in patients with narrow ventricles (frontal occipital horn ratio, 0.38 ± 0.05), a primary puncture of the ventricles was possible in all cases. No VC failure was observed during follow-up (9.1 ± 5.3 months).

CONCLUSIONS

VC placement in narrow ventricles requires accurate placement with simple means in an every-case routine. The suggested smartphone-assisted guide meets these criteria. Further data are planned to be collected in a prospective randomized study.

Frameless robotically targeted stereotactic brain biopsy: feasibility, diagnostic yield, and safety

Object

Frameless stereotactic brain biopsy has become an established procedure in many neurosurgical centers worldwide. Robotic modifications of image-guided frameless stereotaxy hold promise for making these procedures safer, more effective, and more efficient. The authors hypothesized that robotic brain biopsy is a safe, accurate procedure, with a high diagnostic yield and a safety profile comparable to other stereotactic biopsy methods.

Methods

This retrospective study included 41 patients undergoing frameless stereotactic brain biopsy of lesions (mean size 2.9 cm) for diagnostic purposes. All patients underwent image-guided, robotic biopsy in which the SurgiScope system was used in conjunction with scalp fiducial markers and a preoperatively selected target and trajectory. Forty-five procedures, with 50 supratentorial targets selected, were performed.

Results

The mean operative time was 44.6 minutes for the robotic biopsy procedures. This decreased over the second half of the study by 37%, from 54.7 to 34.5 minutes (p < 0.025). The diagnostic yield was 97.8% per procedure, with a second procedure being diagnostic in the single nondiagnostic case. Complications included one transient worsening of a preexisting deficit (2%) and another deficit that was permanent (2%). There were no infections.

Conclusions

Robotic biopsy involving a preselected target and trajectory is safe, accurate, efficient, and comparable to other procedures employing either frame-based stereotaxy or frameless, nonrobotic stereotaxy. It permits biopsy in all patients, including those with small target lesions. Robotic biopsy planning facilitates careful preoperative study and optimization of needle trajectory to avoid sulcal vessels, bridging veins, and ventricular penetration.

External ventricular drainage for intraventricular hemorrhage

Hemorrhagic stroke accounts for only 10% to 15% of all strokes; however, it is associated with devastating outcomes. Extension of intracranial hemorrhage (ICH) into the ventricles or intraventricular hemorrhage (IVH) has been consistently demonstrated as an independent predictor of poor outcome. In most circumstances the increased intracranial pressure and acute hydrocephalus caused by ICH is managed by placement of an external ventricular drain (EVD). We present a systematic review of the literature on the topic of EVD in the setting of IVH hemorrhage, articulating the scope of the problem and prognostic factors, clinical indications, surgical adjuncts, and other management issues.

Cerebrovascular biomodeling for aneurysm surgery: simulation-based training by means of rapid prototyping technologies

OBJECTIVE

Opportunities for developing procedural skills are progressively rare. Therefore, sophisticated educational tools are highly warranted.

METHODS

This study compared stereolithography and 3-dimensional printing for simulating cerebral aneurysm surgery. The latter jets multiple materials simultaneously and thus has the ability to print assemblies of multiple materials with different features. The authors created the solid skull and the cerebral vessels in different materials to simulate the real aneurysm when clipped.

RESULTS

Precise plastic replicas of complex anatomical data provide intuitive tactile views that can be scrutinized from any perspective. Hollowed out vessel sections allow serial clipping efforts, evaluation of different clips, and clip positions. The models can be used for accurate prediction of vascular anatomy, for optimization of teaching surgical skills, for advanced procedural competency training, and for patient counseling.

CONCLUSION

Simultaneous 3-dimensional printing is the most promising rapid prototyping technique to produce biomodels that meet the high demands of neurovascular surgery.

External ventricular drain insertion accuracy: is there a need for change in practice?

OBJECTIVE

Free-hand insertion of an external ventricular drain (EVD) is a common emergency neurosurgical procedure, mostly performed for critically ill patients. Although EVD complications have been studied thoroughly, the accuracy of EVD positioning has been audited only occasionally.

METHODS

Post-EVD insertion computed tomographic scans performed in our unit over a 2-year period were analyzed for EVD tip location and intracranial catheter length.

RESULTS

A total of 183 post-EVD insertion scans were reviewed. Of those, 73 EVD tips (39.9%) were in the ipsilateral frontal horn of the lateral ventricle (the desired target); of those, 18 (25%) required EVD revision/reinsertion. Of the others, 35 (19.1%) were in the third ventricle, 33 (18%) in the body of the lateral ventricle, 19 (10.4%) in the subarachnoid space, 5 (2.7%) in the contralateral frontal horn, and 18 (9.8%) within the brain parenchyma. When the EVD tip was outside the desired target, 44 of the patients (40%) required EVD revision/reinsertion procedure (P = 0.0383).

CONCLUSION

Free-hand insertion of an EVD is an inaccurate procedure, and further studies are required to assess the accuracy and feasibility of the routine use of neuronavigation, ultrasonography, or other guidance techniques and the possible implication of the decreasing revision rate, complications, and length of hospital stay.

Robotic image-guided depth electrode implantation in the evaluation of medically intractable epilepsy

OBJECT

The authors describe their experience with a technique for robotic implantation of depth electrodes in patients concurrently undergoing craniotomy and placement of subdural monitoring electrodes for the evaluation of intractable epilepsy.

METHODS

Patients included in this study underwent evaluation in the Dartmouth Surgical Epilepsy Program and were recommended for invasive seizure monitoring with depth electrodes between 2006 and the present. In all cases an image-guided robotic system was used during craniotomy for concurrent subdural grid electrode placement. A total of 7 electrodes were placed in 4 patients within the time period.

RESULTS

Three of 4 patients had successful localization of seizure onset, and 2 underwent subsequent resection. Of the patients who underwent resection, 1 is now seizure free, and the second has only auras. There was 1 complication after subpial grid placement but no complications related to the depth electrodes.

CONCLUSIONS

Robotic image-guided placement of depth electrodes with concurrent craniotomy is feasible, and the technique is safe, accurate, and efficient.