App-assisted external ventricular drain insertion

The freehand technique for insertion of an external ventricular drain (EVD) is based on fixed anatomical landmarks and does not take individual variations into consideration. A patient-tailored approach based on augmented-reality techniques using devices such as smartphones can address this shortcoming. The Sina neurosurgical assist (Sina) is an Android mobile device application (app) that was designed and developed to be used as a simple intraoperative neurosurgical planning aid. It overlaps the patient's images from previously performed CT or MRI studies on the image seen through the device camera. The device is held by an assistant who aligns the images and provides information about the relative position of the target and EVD to the surgeon who is performing EVD insertion. This app can be used to provide guidance and continuous monitoring during EVD placement. The author describes the technique of Sina-assisted EVD insertion into the frontal horn of the lateral ventricle and reports on its clinical application in 5 cases as well as the results of ex vivo studies of ease of use and precision. The technique has potential for further development and use with other augmented-reality devices.

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sEVD—smartphone-navigated placement of external ventricular drains

Acta Neurochirurgica ◽

10.1007/s00701-019-04131-9 ◽

2019 ◽

Vol 162 (3) ◽

pp. 513-521

Author(s):

Christian V. Eisenring ◽

Felice Burn ◽

Michelle Baumann ◽

Lennart H. Stieglitz ◽

Ralf A. Kockro ◽

...

Keyword(s):

Ex Vivo ◽

Standard Procedure ◽

External Ventricular Drain ◽

Head Model ◽

Anatomical Landmarks ◽

Frontal Horn ◽

Freehand Technique ◽

Multifunctional Device ◽

The Mean ◽

Ct Data

Abstract 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.

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The effect of augmented reality on the accuracy and learning curve of external ventricular drain placement

Neurosurgical FOCUS ◽

10.3171/2021.5.focus21215 ◽

2021 ◽

Vol 51 (2) ◽

pp. E8

Author(s):

Frederick Van Gestel ◽

Taylor Frantz ◽

Cédric Vannerom ◽

Anouk Verhellen ◽

Anthony G. Gallagher ◽

...

Keyword(s):

Augmented Reality ◽

Learning Curve ◽

External Ventricular Drain ◽

Training Session ◽

Freehand Technique ◽

Custom Made ◽

Drain Placement ◽

Improved Performance ◽

The Impact ◽

Better Than

OBJECTIVE The traditional freehand technique for external ventricular drain (EVD) placement is most frequently used, but remains the primary risk factor for inaccurate drain placement. As this procedure could benefit from image guidance, the authors set forth to demonstrate the impact of augmented-reality (AR) assistance on the accuracy and learning curve of EVD placement compared with the freehand technique. METHODS Sixteen medical students performed a total of 128 EVD placements on a custom-made phantom head, both before and after receiving a standardized training session. They were guided by either the freehand technique or by AR, which provided an anatomical overlay and tailored guidance for EVD placement through inside-out infrared tracking. The outcome was quantified by the metric accuracy of EVD placement as well as by its clinical quality. RESULTS The mean target error was significantly impacted by either AR (p = 0.003) or training (p = 0.02) in a direct comparison with the untrained freehand performance. Both untrained (11.9 ± 4.5 mm) and trained (12.2 ± 4.7 mm) AR performances were significantly better than the untrained freehand performance (19.9 ± 4.2 mm), which improved after training (13.5 ± 4.7 mm). The quality of EVD placement as assessed by the modified Kakarla scale (mKS) was significantly impacted by AR guidance (p = 0.005) but not by training (p = 0.07). Both untrained and trained AR performances (59.4% mKS grade 1 for both) were significantly better than the untrained freehand performance (25.0% mKS grade 1). Spatial aptitude testing revealed a correlation between perceptual ability and untrained AR-guided performance (r = 0.63). CONCLUSIONS Compared with the freehand technique, AR guidance for EVD placement yielded a higher outcome accuracy and quality for procedure novices. With AR, untrained individuals performed as well as trained individuals, which indicates that AR guidance not only improved performance but also positively impacted the learning curve. Future efforts will focus on the translation and evaluation of AR for EVD placement in the clinical setting.

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Freehand Insertion of External Ventricular Drainage Catheter–Evaluation of Accuracy in a Single Centre

Neurosurgery ◽

10.1093/neuros/nyz001.tn2 ◽

2019 ◽

Vol 84 (5) ◽

pp. E271-E271 ◽

Cited By ~ 1

Author(s):

Keng Siang Lee ◽

Tseng Tsai Yeo ◽

Ning Chou ◽

Prof Sein Lwin ◽

Kejia Teo ◽

...

Keyword(s):

External Ventricular Drain ◽

External Ventricular Drainage ◽

Burr Hole ◽

Anatomical Landmarks ◽

Midline Shift ◽

Frontal Horn ◽

Significant Difference ◽

Catheter Tip ◽

Procedural Complications ◽

Interhemispheric Fissure

Abstract INTRODUCTION External ventricular drain (EVD) placement is the gold standard for managing acute hydrocephalus. Freehand EVD, using surface anatomical landmarks is performed for ventricular cannulation due to its simplicity and efficiency. This study evaluates accuracy and reason(s) for misplacements as few studies have analyzed the accuracy of freehand EVD insertion. METHODS Preoperative and postoperative computed tomography (CT) scans of patients who underwent EVD insertion in 2014 were retrospectively reviewed. Diagnosis, Evan's ratio, midline shift, position of burr hole, length of the catheter and procedural complications were tabulated. The procedures were classified as satisfactory (catheter tip in the frontal horn ipsilateral lateral ventricle) and unsatisfactory. Unsatisfactory cases were further analyzed in relation to position of burr hole from midline and length of the catheter. RESULTS A total of 77 EVD placements in 70 patients were evaluated. Mean age of the patients was 57.5 yr. About 83.1% were satisfactory placements and 11.7% were unsatisfactory in the contralateral ventricle, corpus callosum and interhemispheric fissure. About 5.2% were in extra ventricular locations. About 2.6% EVD placements were complicated by hemorrhage and 1 catheter was reinserted. Suboptimal placements were significantly associated with longer intracranial catheter length. The mean length was 66.54 ± 10.1 mm in unsatisfactory placements compared to 58.32 ± 4.85 mm in satisfactory placements. Between the 2 groups, no significant difference was observed in Evan's ratio, midline shift, surgeon's experience, distance of burr hole from midline and coronal suture. CONCLUSION Freehand EVD insertion is safe and accurate. In small number of cases, unsatisfactory placement is related to longer catheter length.

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Validation of a freehand technique for cortical bone trajectory screws in the lumbar spine

Journal of Neurosurgery Spine ◽

10.3171/2019.1.spine181402 ◽

2019 ◽

Vol 31 (2) ◽

pp. 201-208 ◽

Cited By ~ 1

Author(s):

Zachary Tan ◽

Stewart McLachlin ◽

Cari Whyne ◽

Joel Finkelstein

Keyword(s):

Lumbar Spine ◽

Cortical Bone ◽

Pedicle Screw ◽

Ex Vivo ◽

Screw Placement ◽

Anatomical Landmarks ◽

Cortical Bone Trajectory ◽

Screw Insertion ◽

Freehand Technique ◽

Ex Vivo Study

OBJECTIVEThe cortical bone trajectory (CBT) technique for pedicle screw placement has gained popularity among spinal surgeons. It has been shown biomechanically to provide better fixation and improved pullout strength compared to a traditional pedicle screw trajectory. The CBT technique also allows for a less invasive approach for fusion and may have lower incidence of adjacent-level disease. A limitation of the current CBT technique is a lack of readily identifiable and reproducible visual landmarks to guide freehand CBT screw placement in comparison to the well-defined identifiable landmarks for traditional pedicle screw insertion. The goal of this study was to validate a safe and intuitive freehand technique for placement of CBT screws based on optimization of virtual CBT screw placement using anatomical landmarks in the lumbar spine. The authors hypothesized that virtual identification of anatomical landmarks on 3D models of the lumbar spine generated from CT scans would translate to a safe intraoperative freehand technique.METHODSCustomized, open-source medical imaging and visualization software (3D Slicer) was used in this study to develop a workflow for virtual simulation of lumbar CBT screw insertion. First, in an ex vivo study, 20 anonymous CT image series of normal and degenerative lumbar spines and virtual screw insertion were conducted to place CBT screws bilaterally in the L1–5 vertebrae for each image volume. The optimal safe CBT trajectory was created by maximizing both the screw length and the cortical bone contact with the screw. Easily identifiable anatomical surface landmarks for the start point and trajectory that best allowed the reproducible idealized screw position were determined. An in vivo validation of the determined landmarks from the ex vivo study was then performed in 10 patients. Placement of virtual “test” cortical bone trajectory screws was simulated with the surgeon blinded to the real-time image-guided navigation, and the placement was evaluated. The surgeon then placed the definitive screw using image guidance.RESULTSFrom the ex vivo study, the optimized technique and landmarks were similar in the L1–4 vertebrae, whereas the L5 optimized technique was distinct. The in vivo validation yielded ideal, safe, and unsafe screws in 62%, 16%, and 22% of cases, respectively. A common reason for the nonidealized trajectories was the obscuration of patient anatomy secondary to severe degenerative changes.CONCLUSIONSCBT screws were placed ideally or safely 78% of the time in a virtual simulation model. A 22% rate of unsafe freehand trajectories suggests that the CBT technique requires use of image-guided navigation or x-ray guidance and that reliable freehand CBT screw insertion based on anatomical landmarks is not reliably feasible in the lumbar spine.

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Laparoscopic augmented reality registration for oncological resection site repair

International Journal of Computer Assisted Radiology and Surgery ◽

10.1007/s11548-021-02336-x ◽

2021 ◽

Author(s):

Fabian Joeres ◽

Tonia Mielke ◽

Christian Hansen

Keyword(s):

Augmented Reality ◽

Time Pressure ◽

Tumour Resection ◽

Anatomical Landmarks ◽

Proof Of Concept ◽

Registration Accuracy ◽

Target Registration Error ◽

Concept Evaluation ◽

Navigation Support ◽

Challenges And Opportunities

Abstract Purpose Resection site repair during laparoscopic oncological surgery (e.g. laparoscopic partial nephrectomy) poses some unique challenges and opportunities for augmented reality (AR) navigation support. This work introduces an AR registration workflow that addresses the time pressure that is present during resection site repair. Methods We propose a two-step registration process: the AR content is registered as accurately as possible prior to the tumour resection (the primary registration). This accurate registration is used to apply artificial fiducials to the physical organ and the virtual model. After the resection, these fiducials can be used for rapid re-registration (the secondary registration). We tested this pipeline in a simulated-use study with $$N=18$$ N = 18 participants. We compared the registration accuracy and speed for our method and for landmark-based registration as a reference. Results Acquisition of and, thereby, registration with the artificial fiducials were significantly faster than the initial use of anatomical landmarks. Our method also had a trend to be more accurate in cases in which the primary registration was successful. The accuracy loss between the elaborate primary registration and the rapid secondary registration could be quantified with a mean target registration error increase of 2.35 mm. Conclusion This work introduces a registration pipeline for AR navigation support during laparoscopic resection site repair and provides a successful proof-of-concept evaluation thereof. Our results indicate that the concept is better suited than landmark-based registration during this phase, but further work is required to demonstrate clinical suitability and applicability.

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Personalized Augmented Reality Based Tourism System: Big Data and User Demographic Contexts

Applied Sciences ◽

10.3390/app11136047 ◽

2021 ◽

Vol 11 (13) ◽

pp. 6047

Author(s):

Soheil Rezaee ◽

Abolghasem Sadeghi-Niaraki ◽

Maryam Shakeri ◽

Soo-Mi Choi

Keyword(s):

Big Data ◽

Augmented Reality ◽

User Study ◽

Spatial Information ◽

Ease Of Use ◽

Tourist Attraction ◽

Gender And Education ◽

Time Distance ◽

Data Source ◽

The Right

A lack of required data resources is one of the challenges of accepting the Augmented Reality (AR) to provide the right services to the users, whereas the amount of spatial information produced by people is increasing daily. This research aims to design a personalized AR that is based on a tourist system that retrieves the big data according to the users’ demographic contexts in order to enrich the AR data source in tourism. This research is conducted in two main steps. First, the type of the tourist attraction where the users interest is predicted according to the user demographic contexts, which include age, gender, and education level, by using a machine learning method. Second, the correct data for the user are extracted from the big data by considering time, distance, popularity, and the neighborhood of the tourist places, by using the VIKOR and SWAR decision making methods. By about 6%, the results show better performance of the decision tree by predicting the type of tourist attraction, when compared to the SVM method. In addition, the results of the user study of the system show the overall satisfaction of the participants in terms of the ease-of-use, which is about 55%, and in terms of the systems usefulness, about 56%.

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Volumetric Video in Augmented Reality Applications for Museological Narratives

Journal on Computing and Cultural Heritage ◽

10.1145/3425400 ◽

2021 ◽

Vol 14 (2) ◽

pp. 1-20

Author(s):

Néill O’dwyer ◽

Emin Zerman ◽

Gareth W. Young ◽

Aljosa Smolic ◽

Siobhán Dunne ◽

...

Keyword(s):

Augmented Reality ◽

Cultural Heritage ◽

Applied Research ◽

Ease Of Use ◽

Museum Visitors ◽

The Public ◽

Research Article ◽

Nature Of Information ◽

Live Action ◽

Capture Technique

Cross-reality technologies are quickly establishing themselves as commonplace platforms for presenting objects of historical, scientific, artistic, and cultural interest to the public. In this space, augmented reality (AR) is notably successful in delivering cultural heritage applications, including architectural and environmental heritage reconstruction, exhibition data management and representation, storytelling, and exhibition curation. Generally, it has been observed that the nature of information delivery in applications created for narrating exhibitions tends to be informative and formal. Here we report on the assessment of a pilot scene for a prototype AR application that attempts to break this mold by employing a humorous and playful mode of communication. This bespoke AR experience harnessed the cutting-edge live-action capture technique of volumetric video to create a digital tour guide that playfully embellished the museological experience of the museum visitors. This applied research article consists of measuring, presenting, and discussing the appeal, interest, and ease of use of this ludic AR storytelling strategy mediated via AR technology in a cultural heritage context.

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Validation of Sonographic Fronto-Occipital Ratio Based on Anatomical Landmarks compared to MR/CT-Derived Indexes in Children with Chiari II and Ventriculomegaly

Pediatric Neurosurgery ◽

10.1159/000521622 ◽

2021 ◽

Author(s):

Michele Retrouvey ◽

Arastoo Vossough ◽

Alireza Zandifar ◽

Richard D. Bellah ◽

Gregory G. Heuer ◽

...

Keyword(s):

Pearson Correlation ◽

Correlation Coefficients ◽

Ventricular Volume ◽

Coronal Plane ◽

Anatomical Landmarks ◽

Foramen Of Monro ◽

Rater Reliability ◽

Unique Challenge ◽

Frontal Horn ◽

Chiari Ii

Introduction: Ultrasound (US) based indexes such as fronto-occipital ratio (FOR) can be used to obtain an acceptable estimation of ventricular volume. Patients with colpocephaly present a unique challenge due to the shape of their ventricles. In the present study, we aim to evaluate the validity and reproducibility of modified US-FOR index in children with Chiari II-related ventriculomegaly. Methods: In this retrospective study, we evaluated Chiari II patients younger than one year who underwent head US and MR or CT scans for ventriculomegaly evaluation. MR/CT based FOR was measured in the axial plane by identifying the widest diameter of frontal horns, occipital horns, and the interparietal diameter (IPD). US based FOR (US-FOR) was measured using the largest diameter based on the following landmarks: frontal horn and IPD in the coronal plane at the level of the foramen of Monro, IPD just superior to the Sylvian fissures, and occipital horn posterior to the thalami and inferior to the superior margins of the thalami. Interclass correlation coefficients (ICC) were used to evaluate inter-rater reliability and Pearson correlation coefficients and Bland-Altman plots were applied to assess agreement between US and other two modalities. Results: Ninety paired US and MR/CT exams were assessed for agreement between US-FOR and MR/CT-FOR measurements. ICC showed an excellent inter-rater reliability for US-FOR (ICC=0.99, p<0.001) and MR/CT-FOR measurements (ICC=0.99, p<0.001). The mean (range) values based on US-FOR showed a slight overestimation in comparison to MR/CT-FOR [0.51 (0.36-0.68) vs 0.46 (0.34-0.64)]. Pearson correlation coefficient showed high cross-modality agreement for the FOR index (r=0.83, p<0.001). Bland-Altman plot showed excellent concordance between US-FOR and MR/CT-FOR with a bias of 0.05 (95% CI, -0.03-0.13) Conclusion: US-FOR in the coronal plane is a comparable tool for evaluating ventriculomegaly in Chiari II patients when compared with MR/CT-FOR, even in the context of colpocephaly.

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Isolated superfused rats atrial model for the investigation of atrial fibrillation mechanisms and treatment

European Heart Journal ◽

10.1093/eurheartj/ehab724.3321 ◽

2021 ◽

Vol 42 (Supplement_1) ◽

Author(s):

S Glatstein ◽

M Ghiringhelli ◽

L Maizels ◽

E Heller ◽

E Maor ◽

...

Keyword(s):

Atrial Fibrillation ◽

High Resolution ◽

Sinus Rhythm ◽

Optical Mapping ◽

Ex Vivo ◽

Anatomical Landmarks ◽

Ex Vivo Model ◽

Electrophysiological Properties ◽

Custom Made ◽

Isolated Atria

Abstract Background One of the major barriers to an improved mechanistic understanding of atrial fibrillation (AF), and thus in the pipeline of drug development, has been a lack of appropriate tissue models, especially in small animals. Aim We propose an advanced anatomical ex-vivo model based on rat atria for acute assessment of AF susceptibility. This novel model could yield a better understanding of arrhythmia mechanisms as well as the development of potential therapeutic strategies for the prevention or termination of atrial arrhythmias. Methods Wistar rats atria (N=25) were isolated, flattened and pinned to a custom-made silicon plate. Atria were superfused with an oxygenized Tyrode's solution. Tissues were then loaded with a voltage-sensitive dye and mapped using a high-resolution optical mapping system. AF was induced with 1uM carbamylcholine (N=23) coupled with pacing maneuvers and treated with 30uM Vernakalant (N=10) or 10uM Flecainide (N=10). Finally, the feasibility of a new ablation technique (electroporation) was evaluated. Results Optical mapping results suggested that the superfusion procedure led to a fast atrial recovery. Sinus activity was conserved for all atria for a long period. All the anatomical landmarks were clearly visualized. The acquired optical signals were analyzed during sinus rhythm and pacing, which allowed the creation of detailed activation maps and measurements of action potential duration (APD) and conduction velocity (CV) at different pacing rates. The resulting APD restitution curves revealed electrical excitation at high pacing rates (cycle length between 50ms and 300ms) with a relatively flattened curve. AF was successfully induced and optically mapping confirmed the presence of reentrant activity. AF was successfully treated using Vernacalant and Flecainide. Finally, we demonstrated the feasibility of a new ablation approach (electroporation) for creation of a continuous linear lesion serving as a functional block. Conclusion The isolated superfused atria model, coupled with voltage-sensitive dyes, can be utilized for long-term high-resolution functional imaging of the atria during sinus rhythm, pacing and arrhythmogenic activity. This allows the study of the atrial electrophysiological properties, the mechanisms involved in AF initiation, perpetuation, and termination as well as the study of drug and new ablation modalities. FUNDunding Acknowledgement Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Research Council (ERC) Spontaneous activation of isolated atria

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Image guidance and improved accuracy of external ventricular drain tip position particularly in patients with small ventricles

Journal of Neurosurgery ◽

10.3171/2017.11.jns171892 ◽

2019 ◽

Vol 130 (4) ◽

pp. 1268-1273 ◽

Cited By ~ 2

Author(s):

Anan Shtaya ◽

Joy Roach ◽

Ahmed-Ramadan Sadek ◽

Benjamin Gaastra ◽

Jonathan Hempenstall ◽

...

Keyword(s):

Propensity Score ◽

Propensity Score Matching ◽

Image Guidance ◽

External Ventricular Drain ◽

Group Versus ◽

Neurosurgical Procedures ◽

Emergency Setting ◽

Optimal Position ◽

Frontal Horn ◽

Evans Index

OBJECTIVEExternal ventricular drain (EVD) insertion is one of the most common emergency neurosurgical procedures. EVDs are traditionally inserted freehand (FH) in an emergency setting, but often result in suboptimal positioning. Image-guided surgery (IGS) is selectively used to assist placement. However, the accuracy and practicality of IGS use is yet to be reported. In this study, the authors set out to assess if IGS is practical and improves the accuracy of EVD placement.METHODSCase notes and images obtained in patients who underwent frontal EVD placement were retrospectively reviewed. Ventriculomegaly was determined by the measurement of the Evans index. EVD location was classified as optimal (ipsilateral frontal horn) or suboptimal (any other location). Propensity score matching of the two groups (IGS vs FH) for the Evans index was performed. Data were analyzed for patient age, diagnosis, number of EVDs, and complications. Those without postoperative CT scans were excluded.RESULTSA total of 607 patients with 760 EVDs placed were identified; 331 met inclusion criteria. Of these, 287 were inserted FH, and 44 were placed with IGS; 60.6% of all unmatched FH EVDs were optimal compared with 75% of the IGS group (p = 0.067). The IGS group had a significantly smaller Evans index (p < 0.0001). Propensity score matching demonstrated improved optimal position in the IGS group when compared with the matched FH group (75% vs 43.2%, OR 4.6 [1.5–14.6]; p = 0.002). Patients with an Evans index of ≥ 0.36 derived less benefit (75% in IGS vs 66% in FH, p = 0.5), and those with an Evans index < 0.36 derived more benefit (75% in IGS vs 53% in FH, p = 0.024). The overall EVD complication rate was 36% in the FH group versus 18% in the IGS group (p = 0.056). Revision rates were higher in the FH group (p = 0.035), and the operative times were similar (p = 0.69). Long intracranial EVD catheters were associated with tip malposition irrespective of the group.CONCLUSIONSImage guidance is practical and improves the accuracy of EVD placement in patients with small ventricles; thus, it should be considered for these patients.

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