External Ventricular Drain Placement Using Active Augmented Reality Guidance

Operative Neurosurgery 30:414–421, 2026

This technical note presents a proof-of-concept augmented reality (AR) system that guides external ventricular drain (EVD) placement by integrating cloud-based automatic CT segmentation, PACS compatibility, trajectory planning, point-based image-to-patient registration, and real-time 3D AR guidance via an AR head-mounted display. The low-cost, end-to-end workflow and universal tracking tools aim to reduce attention shifts and improve accessibility compared with conventional neuronavigation.

The system was tested in a phantom study with 29 AR-guided EVD insertions by neurosurgical clinicians, yielding 69% optimal placements (Kakarla grade 1), a mean distance-to-target of 9.49 mm, mean angular deviation of 9.20°, an FRE of 4.00 mm, and mean procedural time of 22:45. Authors identify human–computer interaction, tracking fidelity, registration accuracy, and procedural time as primary areas for refinement before clinical adoption.

Augmented Reality (AR) Guidance: A low-cost, end-to-end AR system was developed for external ventricular drain (EVD) placement, integrating real-time 3D guidance, automated CT segmentation, and compatibility with standard hospital PACS infrastructure, all visualized through AR head-mounted displays (AR-HMDs).

Workflow Components: The system includes cloud-based image storage, automatic segmentation, trajectory planning, point-based image-to-patient registration, and real-time EVD tracking, aiming to reduce attention shifts and improve procedural integration.

Proof-of-Concept Results: In simulated procedures on anatomical phantoms with small ventricles, 69% of placements were optimal (Kakarla 1), with a mean distance to target of 9.49 mm and mean angular deviation of 9.20°, but accuracy is not yet at the level of best clinical standards.

Procedural Time: The mean workflow duration was nearly 23 minutes, which is longer than acceptable for emergency EVD placements, with most of the added time attributed to trajectory planning, marker attachment, and image-to-patient registration.

Usability and Interface Challenges: Users experienced difficulties with human-computer interaction, including issues with holographic controls, visual clutter, and marker tracking, which impacted both speed and accuracy.

Affordability and Accessibility: The AR-HMD system (approx. $4950) is significantly less expensive than traditional neuronavigation systems, potentially increasing access to advanced guidance in resource-limited settings

Lumbar Puncture or External Ventricular Drainage as Initial Treatment for Acute Hydrocephalus in Aneurysmal Subarachnoid Hemorrhage

Neurosurgery 97:1308–1315, 2025

This two-center cohort study compares lumbar puncture (LP) versus external ventricular drainage (EVD) as initial treatments for acute hydrocephalus after aneurysmal subarachnoid hemorrhage, analyzing rates of permanent ventriculoperitoneal shunts (VPS), procedure-related complications, and 3-month functional outcomes. Patients eligible for LP had similar admission severity, and outcomes were adjusted for baseline predictors to compare strategies across centers.

Results show markedly fewer permanent VPS implantations (10% vs 68%) and lower short-term complication rates with LP, while unfavorable functional outcomes at 3 months did not differ significantly. The authors conclude LP is a viable initial option for selected patients, recommending future studies on cognitive and quality-of-life effects.

Initial Treatment: Lumbar puncture (LP) as initial treatment for acute hydrocephalus after aneurysmal subarachnoid hemorrhage (SAH) resulted in significantly fewer patients requiring permanent ventriculoperitoneal shunt (VPS) implantation compared to external ventricular drainage (EVD) (10% vs 68%).

Complication Rates: LP was associated with lower short-term complication rates than EVD (21% vs 38%), including lower rates of intracerebral hemorrhage and infection, especially when LP alone was sufficient.

Functional Outcomes: No statistically significant difference was observed in unfavorable functional outcomes (Glasgow Outcome Scale 1-3 at 3 months) between LP and EVD groups, though the trend favored LP (40% vs 49%).

Patient Selection: LP is suitable as first-line treatment only for selected patients (e.g., GCS ≥7, no space-occupying hematoma, no intraventricular obstruction), while EVD remains necessary for those with contraindications to LP or requiring intracranial pressure monitoring.

Volume of CSF Drainage: Lower cerebrospinal fluid (CSF) volumes drained with LP (typically 25-30 mL per procedure) compared to EVD (hundreds of mL over days) may contribute to reduced VPS dependency.

Study Limitations: Differences in overall management strategies, patient selection, and treatment protocols between centers limit the ability to attribute outcomes solely to the initial hydrocephalus treatment modality; results should not be interpreted as definitive evidence that LP is superior to EVD.

Implications for Practice: LP can be considered as an initial treatment for acute hydrocephalus after SAH in eligible patients, but there is currently no evidence that it improves long-term functional outcomes; further research is needed to assess effects on cognition and quality of life.

Research Needs: More robust, prospective studies are required to clarify optimal patient selection, CSF drainage strategies, and comparative benefits of LP versus EVD in post-SAH hydrocephalus management.

Training on a 3D-Printed Simulation Model Improves Accuracy in External Ventricular Drain Placement

Operative Neurosurgery 29:418–427, 2025

Training neurosurgeons on a 3D-printed simulation model with a standardized protocol significantly improved external ventricular drain (EVD) placement accuracy, reduced variability, and increased confidence, benefitting both junior and experienced practitioners. Regular simulation-based training is recommended to maintain high clinical performance and standardize EVD procedures.

• 3D-printed head models were developed for training neurosurgical residents in external ventricular drain (EVD) placement.

• Training included pre-training, standardized protocol with neuronavigation, and post-training rounds.

• EVD placement accuracy improved significantly after training, with optimal placement rates rising from 55% to 84%.

• Distances to ideal entry and target points, as well as procedure times, were significantly reduced post-training.

• Experience alone did not predict accuracy; even senior neurosurgeons improved, and post-training results were similar across experience levels.

• Right-handed participants achieved better outcomes using their right hand for both sides; left-sided EVDs were more often misplaced.

• Participants’ confidence in EVD placement and direction increased after training.

• Regular, standardized simulation training is recommended for all neurosurgeons, regardless of experience, to maintain high clinical performance.

External Ventricular Drain Misadministration Events

Operative Neurosurgery 29:345–350, 2025

This systematic review examines misadministration events involving external ventricular drains (EVDs), including the first reported case of blood transfusion through an EVD. It highlights risk factors, advocates for ISO 80369-6 NRFit connectors to prevent misconnections, and recommends enhanced protocols and staff education to improve patient safety.

• External ventricular drains (EVDs) are widely used in neurosurgery but carry risks of misadministration due to connector similarity with IV lines.

• A systematic review identified 7 reports (8 cases) of EVD misadministration, involving drugs like gadolinium, anesthetics, antiepileptics, and, for the first time, blood products.

• The first reported case of blood transfusion into an EVD resulted in patient death, highlighting the severity of such errors.

• Main contributing factors include unfamiliarity with EVD systems, similar appearance to IV tubing, and poor visibility during procedures.

• The new ISO 80369-6 standard and NRFit connectors, with a smaller diameter than Luer connectors, are designed to prevent misconnections.

• Adoption of NRFit connectors, staff training, and clear equipment labeling are key recommended preventive strategies.

• Current guidelines from professional organizations support design changes and staff education but lack universal protocols for EVD management.

• Further research and widespread implementation of standardized connectors are needed to improve patient safety.

sEVD—smartphone-navigated placement of external ventricular drains

Acta Neurochirurgica (2020) 162:513–521

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, angleadjusted 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 33mm 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.

A wearable mixed-reality holographic computer for guiding external ventricular drain insertion at the bedside

J Neurosurg 131:1599–1606, 2019

The goal of this study was to explore the feasibility and accuracy of using a wearable mixed-reality holographic computer to guide external ventricular drain (EVD) insertion and thus improve on the accuracy of the classic freehand insertion method for EVD insertion. The authors also sought to provide a clinically applicable workflow demonstration.

METHODS Pre- and postoperative CT scanning were performed routinely by the authors for every patient who needed EVD insertion. Hologram-guided EVD placement was prospectively applied in 15 patients between August and November 2017. During surgical planning, model reconstruction and trajectory calculation for each patient were completed using preoperative CT. By wearing a Microsoft HoloLens, the neurosurgeon was able to visualize the preoperative CT-generated holograms of the surgical plan and perform EVD placement by keeping the catheter aligned with the holographic trajectory. Fifteen patients who had undergone classic freehand EVD insertion were retrospectively included as controls. The feasibility and accuracy of the hologram-guided technique were evaluated by comparing the time required, number of passes, and target deviation for hologram-guided EVD placement with those for classic freehand EVD insertion.

RESULTS Surgical planning and hologram visualization were performed in all 15 cases in which EVD insertion involved holographic guidance. No adverse events related to the hologram-guided procedures were observed. The mean ± SD additional time before the surgical part of the procedure began was 40.20 ± 10.74 minutes. The average number of passes was 1.07 ± 0.258 in the holographic guidance group, compared with 2.33 ± 0.98 in the control group (p < 0.01). The mean target deviation was 4.34 ± 1.63 mm in the holographic guidance group and 11.26 ± 4.83 mm in the control group (p < 0.01).

CONCLUSIONS This study demonstrates the use of a head-mounted mixed-reality holographic computer to successfully perform hologram-assisted bedside EVD insertion. A full set of clinically applicable workflow images is presented to show how medical imaging data can be used by the neurosurgeon to visualize patient-specific holograms that can intuitively guide hands-on operation. The authors also provide preliminary confirmation of the feasibility and accuracy of this hologram-guided EVD insertion technique.

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

J Neurosurg 130:1268–1273, 2019

External 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.

METHODS Case 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.

RESULTS A 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.

CONCLUSIONS Image guidance is practical and improves the accuracy of EVD placement in patients with small ventricles; thus, it should be considered for these patients.

App-assisted external ventricular drain insertion

app-assisted-external-ventricular-drain-insertion

J Neurosurg 125:754–758, 2016

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.

Terson syndrome in aneurysmal subarachnoid hemorrhage

Terson syndrome

Acta Neurochir (2016) 158:1027–1036

A large number of reports have not been able to clarify the pathophysiology of Terson syndrome (TS) in aneurysmal subarachnoid hemorrhage (aSAH).

Methods Prospective single-center study on aSAH patients. Fundoscopic and radiological signs of TS were assessed. The opening intracranial pressure (ICP) in patients who required a ventriculostomy was recorded with a manometer.

Results Six out of 36 included patients had TS (16.7 %), which was associated with unfavorable admission scores. Twenty-nine patients (80.5 %) required ventriculostomy; TS was associated with higher ICP (median, 40 vs. 15 cm cmH2O, p= .003); all patients with TS had pathological ICP values of >20 cmH2O. Patients with a ruptured aneurysm of the anterior cerebral artery complex were ten times as likely to suffer from TS (OR 10.0, 95 % CI 1.03–97.50). Detection of TS on CT had a sensitivity of 50 %, a specificity of 98.4 %, a positive predictive value of 83.3 %, and a negative predictive value of 92.4 %. Mortality was 45 times as high in patients with TS (OR 45.0, 95 % CI 3.86–524.7) and neurologic morbidity up until 3 months post-aSAH was significantly higher in patients with TS (mRS 4–6; 100 vs. 17 %; p = .001).

Conclusions Our findings demonstrate an association between raised ICP and the incidence of TS. TS should be ruled out in aSAH patients presenting comatose or with raised ICP to ensure upfront ophthalmological follow-up. In alert patients without visual complaints and a TS-negative CT scan, the likelihood for the presence of TS is very low.

Hemorrhagic complications of ventriculostomy: incidence and predictors in patients with intracerebral hemorrhage

Optimal trajectory of endoscopic third ventriculostomy

J Neurosurg 120:931–936, 2014

Ventriculostomy—the placement of an external ventricular drain (EVD)—is a common procedure performed in patients with acute neurological injury. Although generally considered a low-risk intervention, recent studies have cited higher rates of hemorrhagic complications than those previously reported. The authors sought to determine the rate of postventriculostomy hemorrhage in a cohort of patients with intracerebral hemorrhage (ICH) and to identify predictors of hemorrhagic complications of EVD placement.

Methods. Patients with ICH who underwent EVD placement and had both pre- and postprocedural imaging available for analysis were included in this study. Relevant data were prospectively collected for each patient who satisfied inclusion criteria. Variables with a p < 0.20 on univariate analyses were included in a stepwise logistic regression model to identify predictors of postventriculostomy hemorrhage.

Results. Sixty-nine patients were eligible for this analysis. Postventriculostomy hemorrhage occurred in 31.9% of patients. Among all patients with intraparenchymal hemorrhage, the mean hemorrhage volume was 0.66 ± 1.06 cm3. Stratified according to ventricular catheter diameter, patients treated with smaller-diameter catheters had a significantly greater mean hemorrhage volume than patients treated with larger-diameter catheters (0.84 ± 1.2 cm3 vs 0.14 ± 0.12 cm3, p = 0.049). Postventriculostomy hemorrhage was clinically significant in only 1 patient (1.4%). Overall, postventriculostomy hemorrhage was not associated with functional outcome or mortality at either discharge or 90 days. In the multivariate model, an age > 75 years was the only independent predictor of EVD-associated hemorrhage.

Conclusions. Advanced age is predictive of EVD-related hemorrhage in patients with ICH. While postventriculostomy hemorrhage is common, it appears to be of minor clinical significance in the majority of patients.

A Simple Protocol to Prevent External Ventricular Drain Infections

A_Simple_Protocol_to_Prevent_External_Ventricular

Neurosurgery 72:993–999, 201

External ventricular drains (EVDs) are associated with high rates of infection, and EVD infections cause substantial morbidity and mortality.

OBJECTIVE: To determine whether the introduction of an evidence-based EVD infection control protocol could reduce the rate of EVD infections.

METHODS: This was a retrospective analysis of an EVD infection control protocol introduced in a tertiary care neurointensive care unit. We compared rates of cerebrospinal fluid culture positivity and ventriculitis for the 3 years before and 3 years after the introduction of an evidence-based EVD infection control protocol. A total of 262 EVD placements were analyzed, with a total of 2499 catheter-days.

RESULTS: The rate of cerebrospinal fluid culture positivity decreased from 9.8% (14 of 143; 11.43 per 1000 catheter-days) at baseline to 0.8% (1 of 119; 0.79 per 1000 catheterdays) in the EVD infection control protocol period (P = .001). The rate of ventriculitis decreased from 6.3% (9 of 143; 7.35 per 1000 catheter-days) to 0.8% (1 of 119; 0.79 per 1000 catheter-days; P = .02).

CONCLUSION: The introduction of a simple, evidence-based infection control protocol was associated with a dramatic reduction in the risk of EVD infection.

Ventricular Catheter Location and the Clearance of Intraventricular Hemorrhage

Neurosurgery 70:1258–1264, 2012 DOI: 10.1227/NEU.0b013e31823f6571

There is no consensus regarding optimal position of an external ventricular drain (EVD) with regard to clearance of intraventricular hemorrhage (IVH).

OBJECTIVE: To assess the hypothesis that EVD laterality may influence the clearance of blood from the ventricular system with and without administration of thrombolytic agent.

METHODS: The EVD location was assessed in 100 patients in 2 Clot Lysis Evaluating Accelerated Resolution of Intraventricular Hemorrhage (CLEAR IVH) phase II trials assessing the safety and dose optimization of thrombolysis through the EVD to accelerate the clearance of obstructive IVH. Laterality of catheter was correlated with clearance rates.

RESULTS: Clearance of IVH over the first 3 days was significantly greater when thrombolytic compared with placebo was administered regardless of catheter laterality (P , .005; 95% confidence interval, 214.0 to 24.14 for contralateral EVD and 224.7 to 25.44 for ipsilateral EVD). When thrombolytic was administered, there was a trend toward more rapid clearance of total IVH through an EVD placed on the side of dominant intraventricular blood compared with an EVD on the side with less blood (P = .09; 95% confidence interval, 29.62 to 0.69). This was not true when placebo was administered. Clearance of third and fourth ventricular blood was unrelated to EVD laterality.

CONCLUSION: It is possible that placement of EVD may be optimized to enhance the clearance of total IVH if lytic agents are used. Catheters on either side can clear the third and fourth ventricles with equal efficiency.

Prevention of Ventriculostomy-Related Infections With Prophylactic Antibiotics and Antibiotic- Coated External Ventricular Drains: A Systematic Review

Neurosurgery 68:996–1005, 2011 DOI: 10.1227/NEU.0b013e3182096d84

Ventriculostomy-related infection (VRI) is a severe complication of external ventricular drain use, occurring in 5% to 23% of patients. Preventive measures for VRI include prolonged prophylactic systemic antibiotics (PSAs) and an antibioticcoated external ventricular drains (ac-EVDs).

OBJECTIVE: We performed a systematic review of all studies evaluating PSAs and ac-EVD for VRI prevention through July 2010.

METHODS: Two reviewers independently assessed eligibility and evaluated study quality based on pre-established criteria. Observational studies and randomized clinical trials (RCTs) that fulfilled inclusion criteria were included in the meta-analysis.

RESULTS: Three RCTs and 7 observational studies met our inclusion criteria and were included in the analysis. The type of antibiotics and VRI definitions varied among these studies. Pooled analysis showed a protective effect of PSAs and ac-EVDs for VRI (risk ratio: 0.32; 95% CI: 0.18-0.56). Results showed moderate heterogeneity (I2 = 53%) explained by the difference in quality among the studies and the inclusion of 1 large positive cohort study. The effect of PSAs and ac-EVDs was unrelated to the type of study (RCT or observational, P for interaction = .55), the route of antibiotic administration (PSAs or ac-EVDs, P = .13), or the quality of the studies (suboptimal vs good/excellent, P = .55).

CONCLUSION: RCTs and observational-derived evidence support the use of PSAs throughout the duration of external ventricular drainage; similarly, the use of ac-EVDs to prevent VRI seems to be beneficial. Available data are heterogeneous and of suboptimal quality. Further research is needed to confirm the findings of this meta-analysis. There are not sufficient data to compare the protective effect of ac-EVDs and PSAs.

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

Neurosurgery 65:1197–1201, 2009.DOI: 10.1227/01.NEU.0000356973.39913.0B

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 tar- get); 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 sub- arachnoid 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 neuro- navigation, ultrasonography, or other guidance techniques and the possible implication of the decreasing revision rate, complications, and length of hospital stay.