External Ventricular Drain Placement Stealth Study

March 12, 2026 updated by: University of Wisconsin, Madison

Application of Image Guidance Technology to Bedside External Ventricular Drain Placement

External ventricular drain (EVD) placement is performed very often in neurosurgical practices. EVD's are most commonly placed at the bedside using external anatomical landmarks to guide the catheter into the frontal horn of the ipsilateral lateral ventricle. EVDs are often placed due to acute neurological compromise and require timely insertion.

Accurate catheter placement is essential to achieving effective external CSF drainage without complications or occlusion/failure of the catheter. Catheter placement is most commonly performed via a freehand approach using external anatomical landmarks to help identify the location of the lateral ventricle within the brain without the aid of imaging. Proper identification of the ventricles on pre-procedure imaging, surgeon skill, and estimation of pathologic perturbations to the normal location of the ventricles all factor into the success of catheter placement. Multiple passes are often required. The accuracy rate from the freehand technique has been reported to range from 40 to 98 percent.

Current methods for EVD placement do not compensate for superficial brain vessels or pathology that may alter the intracranial anatomy such as trauma, hemorrhage, or mass lesions. Some studies have attempted to use CTA imaging to identify intracranial vessels in an attempt to avoid them during placement.

Image guidance is a tool used very commonly for placement of EVD's and shunts in the operating room. AxiEM Stealth is a noninvasive image localization modality that registers a CT or MRI to the individual patients facial and scalp anatomy.

This study will compare the current standard of care of freehand placement of bedside external ventricular catheters to the placement of EVD catheters with AxiEM Stealth image guidance.

Study Overview

Status

Terminated

Conditions

Intervention / Treatment

Detailed Description

External ventricular drain (EVD) placement is performed very often in neurosurgical practices. EVD's are used most commonly to monitor intracranial pressure and divert cerebrospinal fluid (CSF) in patients with increased intracranial pressures. Pathologies where EVDs are most frequently needed include hydrocephalus, malignancy, and/or trauma. EVD's are most commonly placed at the bedside using external anatomical landmarks to guide the catheter into the frontal horn of the ipsilateral lateral ventricle. EVDs are often placed due to acute neurological compromise and require timely insertion. This can increase the associated risk and result in complications.

Accurate catheter placement is essential to achieving effective external CSF drainage without complications or occlusion/failure of the catheter. Catheter placement is most commonly performed via a freehand approach using external anatomical landmarks to help identify the location of the lateral ventricle within the brain without the aid of imaging. Proper identification of the ventricles on pre-procedure imaging, surgeon skill, and estimation of pathologic perturbations to the normal location of the ventricles all factor into the success of catheter placement. Multiple passes are often required. The accuracy rate from the freehand technique has been reported to range from 40 to 98 percent. A very basic grading scale has been developed to assess placement but does not include items such as the number of passes until successful placement and presence of post placement hemorrhage or other neurological complications. An increased number of passes increases the risk of post placement hemorrhage and may damage the brain. Hemorrhage has been reported to occur after catheter placement at rates ranging from 0.2 to 41 percent.

Current methods for EVD placement do not compensate for superficial brain vessels or pathology that may alter the intracranial anatomy such as trauma, hemorrhage, or mass lesions. Some studies have attempted to use CTA imaging to identify intracranial vessels in an attempt to avoid them during placement.

Image guidance is a tool used very commonly for placement of EVD's and shunts in the operating room. AxiEM Stealth is a noninvasive image localization modality that registers a CT or MRI to the individual patients facial and scalp anatomy. A probe can then be used to identify, in real-time, the underlying anatomy and trajectories. This imaging guidance may improve the accuracy of EVD placement.

This study will compare the current standard of care of freehand placement of bedside external ventricular catheters to the placement of EVD catheters with AxiEM Stealth image guidance. Accuracy of the tip of the catheter, occurrence of post-placement hemorrhage, the number of passes required for CSF flow, ventricle diameter, catheter clogging/failure, time required for placement, patient demographics and other secondary outcome measures such as Glasgow Outcome Scale (GOS) and Modified Rankin Score (MRS) will be collected. The hypothesis is that image guided EVD catheter placement will improve accuracy, decrease the number of brain transgressions, and decrease complications of EVD placement.

What makes up an external ventricular drain and how does it work? An external ventricular drain (EVD) is comprised of a catheter, drainage tubing, and a collection system. Once the catheter is in the ventricular system, it works by measuring the intracranial pressure via a transducer and drains excess CSF from the ventricular system to ensure pressures does not exceed a set threshold. Normal intracranial pressures range from about 5-20 mmHg and are usually around 10mmHg. The EVD system can be set at a certain level and when the intracranial pressures rise above that level, CSF drains out the catheter into the collecting system. The EVD system can be raised or lowered to create different intracranial pressure thresholds and keep intracranial pressures controlled in patients that have a pathology, such as cerebral swelling or ventricular obstruction, leading to increased pressures.

What is the current technique used to place an EVD? A sterile field is prepared about 10-12 centimeters posterior to the eye (either right or left as clinically indicated) and about 2-3 cm lateral to the midline of the skull. This point should be about 1 cm anterior to the coronal suture. An incision is made at this point and a burr hole is created using a hand drill. The EVD catheter is prepared using a stylet to help with movement through the brain parenchyma. The catheter is advanced in a trajectory perpendicular to the skull, which results in a direction that is towards the ipsilateral medial canthus and ipsilateral tragus which are other landmarks that can be used. The catheter is advanced to 5-6 cm and the stylet is removed to assess for CSF flow. If CSF flow is not appreciated, then the catheter is passed softly for about 1 more centimeter. If CSF flow is still not appreciated, the catheter is removed and the stylet replaced for another attempt. If unsuccessful after 3 attempts, the catheter can be left in place and a head CT can be done to assess the adjustments that need to be made. This can often take up to 10 passes or more if there is significant brain shift due to mass effect or aberrant anatomy. Once CSF flow is obtained, the catheter is tunneled posteriorly and anchored to the skin with a stitch. The incision is then closed and the catheter is connected to the drainage tubing of the collection system. The presence of CSF drainage is checked at multiple points during closure to ensure that the catheter remains in good position.

How does Axiem Stealth work as an image guidance system and how is it used for EVD placement? The first step for using the image guidance system is to upload the most recent (since admission or within 6 hours from bleeding) head CT or MRI into the Stealth station that has been obtained since admission. The Axiem Stealth imaging guidance system uses a probe (AxiEM Registration Probe) and a side mount emitter (AxiEM Side Mount Emitter) to register the patient's head in relation to the probe. A trajectory (entry point and target) is then planned. This registration process takes an estimated 5-15 minutes to perform. A separate stylet (StealthStation EM Stylet) is designed specifically for the catheter and slides down the center of the catheter. A burr-hole is created at the predefined precise location and the catheter is passed to the target under electromagnetic guidance.

Relevance of this research:

The novelty of this study is to investigate whether using image guidance technology can improve EVD catheter placement. Image guidance is used very commonly for EVD and shunt placement in the operating room with excellent accuracy and precision. The hypothesis is that using this same workflow at the bedside will improve accuracy; decrease the number of passes needed for a successful placement, decrease the number of post-placement hemorrhagic events, and help improve the effectiveness of the catheter as well as patient outcomes.

Study Type

Interventional

Enrollment (Actual)

31

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Wisconsin
      • Madison, Wisconsin, United States, 53792
        • University of Wisconsin-Madison

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 88 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Patients undergoing bedside external ventricular drain placement determined by attending physician
  • Age ≥ 18 years and ≤ 88 years
  • Male or Female
  • Patients or consentable family member must sign a written informed consent prior to EVD placement
  • Stealth compatible head CT or MRI

Exclusion Criteria:

  • Patients ≤ 18 and ≥ 88 years of age
  • Prisoner status
  • Subjects who decline participation into the study
  • Subjects determined to be medically or neurologically to high of a risk for the study, determined by attending physician
  • Patients who undergo emergent EVD placement via emergency consent
  • Subjects for whom self-consent or consent by a LAR cannot be obtained or cannot be obtained
  • Pregnant women
  • Non-English speaking patients

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: EVD placement
Catheter placement is most commonly performed via a freehand approach using external anatomical landmarks to help identify the location of the lateral ventricle within the brain without the aid of imaging. Proper identification of the ventricles on pre-procedure imaging, surgeon skill, and estimation of pathologic perturbations to the normal location of the ventricles all factor into the success of catheter placement. Multiple passes are often required. The accuracy rate from the freehand technique has been reported to range from 40 to 98 percent.
Other: EVD placement
A sterile field is prepared about 10-12 centimeters posterior to the eye and about 2-3 cm lateral to the midline of the skull. An incision is made at this point and a burr hole is created using a hand drill. The catheter is advanced in a trajectory perpendicular to the skull, which results in a direction that is towards the ipsilateral medial canthus and ipsilateral tragus which are other landmarks that can be used.
Experimental: Axium Stealth Image Guidance
The novelty of this study is to investigate whether using image guidance technology can improve EVD catheter placement. Image guidance is used very commonly for EVD and shunt placement in the operating room with excellent accuracy and precision. We hypothesize that using this same workflow at the bedside will improve accuracy; decrease the number of passes needed for a successful placement, decrease the number of post-placement hemorrhagic events, and help improve the effectiveness of the catheter as well as patient outcomes.
Other: EVD placement
A sterile field is prepared about 10-12 centimeters posterior to the eye and about 2-3 cm lateral to the midline of the skull. An incision is made at this point and a burr hole is created using a hand drill. The catheter is advanced in a trajectory perpendicular to the skull, which results in a direction that is towards the ipsilateral medial canthus and ipsilateral tragus which are other landmarks that can be used.
Other: Axium Steatlh Image Guidance
The Axiem Stealth imaging guidance system uses a probe (AxiEM Registration Probe) and a side mount emitter (AxiEM Side Mount Emitter) to register the patient's head in relation to the probe. A trajectory (entry point and target) is then planned. This registration process takes an estimated 5-15 minutes to perform. A separate stylet (StealthStation EM Stylet) is designed specifically for the catheter and slides down the center of the catheter. A burr-hole is created at the predefined precise location and the catheter is passed to the target under electromagnetic guidance.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Number of catheter passes or attempts
Time Frame: baseline
Collection of number of passes needed for successful catheter placement
baseline
Accuracy of catheter tip compared to foramen of Monro
Time Frame: baseline
Measurement of accuracy for catheter tip compared to foramen of Monro with accuracy formula
baseline

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Occurrence of post-placement hemorrhage
Time Frame: baseline and 12 months
Anotation of occurrence of hemorrhage post-catheter placement by either freehand or image guided
baseline and 12 months
New neurological deficits
Time Frame: baseline and 12 months
Utilization of the Glasgow Come Score and mRS scale to measure new neurological symptoms
baseline and 12 months
Durability of EVD
Time Frame: baseline and 12 months
Presence of clogging/ failure
baseline and 12 months
Time required catheter insertion
Time Frame: baseline
Anotation of time allocation for catheter insertion - both methods
baseline
Infection rate
Time Frame: baseline and 12 months
Occurrence of ventriculostomy infection (meningitis, ventriculitis, cerebritis)
baseline and 12 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Wisconsin, Madison

Investigators

  • Principal Investigator: Azam Ahmed, MD, University of Wisconsin, Madison

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

August 15, 2018

Primary Completion (Actual)

March 12, 2026

Study Completion (Actual)

March 12, 2026

Study Registration Dates

First Submitted

May 24, 2018

First Submitted That Met QC Criteria

October 3, 2018

First Posted (Actual)

October 4, 2018

Study Record Updates

Last Update Posted (Actual)

March 16, 2026

Last Update Submitted That Met QC Criteria

March 12, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • 2017-1487
  • A535700 (Other Identifier: UW Madison)
  • SMPH/NEURO SURG/NEURO SURG (Other Identifier: UW Madison)
  • Protocol Version 8/8/2024 (Other Identifier: UW Madison)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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