A Bedside, Single Burr Hole Approach to Multimodality Monitoring in Severe Brain Injury
March 26th, 2019
A method of recording multimodality monitoring signals in patients with severe brain injuries using a bedside, single burr hole technique is described.
The placement of a quad lumen monitor can allow for the collection of different types of data including intracranial pressure, brain tissue oxygenation, cerebral blood flow, and electrical activity. Our protocol allows different types of information to be collected in severe traumatic brain injury patients at the bedside using a simple procedure involving a single burr hole. Immobilize the head securely to ensure that it does not move during burr hole placement.
Rolled towels and tape can be used to help secure the patient's head. Begin by identifying the correct location for the bolt placement. 11 centimeters from the nasion or one centimeter anterior to the coronal suture, and two to three centimeters laterally at about the mid-pupillary line.
Sterilize the area with Betadine solution and use 1%lidocaine with epinephrine for local analgesia. While the Betadine is drying, thread each probe through a locking nut, and subsequently insert each probe through one of the lumens of the bolt. Place the intracranial pressure brain tissue oxygen probe preferentially in the tallest lumen.
The other probes can be fit through any of the remaining lumens. Confirm that the distance from the end of the bolt to the tip of each probe is two and a half to three centimeters, and advance the depth electrode until the most proximal electrode is just outside the end of the bolt. Once the probe has been placed the appropriate distance from the end of the bolt, tighten the locking nut on the lumen of the bolt, and then on the probe itself to lock the probe in place.
Then loosen the nut from the lumen and remove each probe with its locking nut in place, placing each probe on the sterile table next to the bolt. When all of the probes are ready, use a scalpel to make a one to two centimeter incision in the marked region, and use a blunt tipped instrument to separate the subgaleal tissues to expose the periosteum. Use a hex bit to tighten a 5.3 millimeter drill bit to the cranial drill, and place the drill perpendicular to the skull.
Using continuous pressure while rotating the instrument, drill until there is a tactile change in pressure, and continue drilling with counter upward support to avoid plunging the drill into the cortex. Remove the drill and clear the burr hole of any bone chips or debris. Use a scalpel to incise the dura in a cruciate fashion and confirm that the dura is completely open.
To insert the cranial bolt, hold the bolt by the plastic wings and thread the bolt through the burr hole with a firm clockwise twisting motion. Insert the thinnest pre-measured probe until the locking nut meets the lumen, followed by the rest of the probes. Insert the depth electrode with the stylet in place, and tighten the electrode on the lumen.
Then gently loosen the locking nut from the probe, just enough to remove the stylet, before re-tightening the nut. When all of the probes have been inserted, have available personnel connect the intracranial pressure brain tissue oxygen probe to the bedside monitor, to assess the intracranial pressure and brain tissue oxygen. Then use durable tape to gently loop each probe to secure it to its lumen to create strain resistance.
If desired, wrap the probes and bolt with sterile gauze at the completion of the procedure. All probes project through the bolt into the brain parenchyma within millimeters of each other. Here, scout computed tomography, or CT coronal and sagittal images, demonstrating the trajectory of probes at approximately 1.5 and two to three centimeters respectively below the inner table of the skull are shown.
In this axial CT image, a probe placed after non-surgical severe traumatic brain injury with excellent placement can be observed. Note that with standard windowing, relatively dense probes may obscure subtle peri-probe hematomas. This axial CT image of a probe placed after surgical severe traumatic brain injury illustrates the location of a bolt and probes contralateral to the hemicraniectomy site.
These incorrectly placed probes after non-surgical severe traumatic brain injury are approaching the frontal horn of the lateral ventricle, indicating that they are greater than three centimeters below the inner table of the skull, which may affect measurements obtained by the probes. Place the probes at the proper depth from the bottom of the bolt and tighten the locking nuts tightly enough that the probes do not get dislodged without becoming damaged. If intracranial pressures are high and refractory to treatment, an external ventricular drain can also be placed to drain cerebrospinal fluid and relieve intracranial pressure.
A continuous scalp electroencephalography electrode can be placed to correlate potential seizure activity with the depth electrode findings.
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Overview
This study describes a method for recording multimodality monitoring signals in patients with severe brain injuries using a bedside, single burr hole technique. The protocol allows for the collection of intracranial pressure, brain tissue oxygenation, cerebral blood flow, and electrical activity, providing a comprehensive approach to monitor these patients effectively.
Key Study Components
Area of Science
- Neuroscience
- Trauma medicine
- Electrophysiology
Background
- Severe traumatic brain injury poses significant monitoring challenges.
- Continuous assessment of intracranial conditions is crucial for patient management.
- Traditional methods may be invasive and not suitable for bedside monitoring.
- A simpler approach could improve safety and accessibility for critically ill patients.
Purpose of Study
- To develop a bedside technique for multimodality monitoring.
- To ensure accurate tracking of key neurological parameters.
- To minimize invasiveness while maximizing data collection.
Methods Used
- The study employs a single burr hole technique for probe placement.
- The biological model includes severe traumatic brain injury patients.
- No multiomics workflow is mentioned in the text.
- Key steps involve precise location identification, sterilization, probe insertion, and monitoring setup.
- Probes are critically positioned to collect accurate measurements from brain tissue.
Main Results
- The method enables simultaneous recording of multiple monitoring signals.
- Successful probe placement ensures reliable collection of intracranial pressure and oxygenation data.
- Probes are positioned within millimeters of each other for optimal measurement accuracy.
- Identification of proper probe depth is crucial for effective monitoring.
Conclusions
- This study demonstrates the feasibility of a less invasive monitoring technique at the bedside.
- It enables comprehensive data collection to inform clinical decisions in severe brain injury management.
- The protocol contributes to improved patient outcomes through better monitoring and intervention strategies.
Frequently Asked Questions
Executive Industry Relevance
This bedside multimodality monitoring approach addresses a critical gap in neurocritical care by enabling simultaneous measurement of intracranial pressure, brain tissue oxygenation, cerebral blood flow, and electrophysiological activity through a single burr hole. The method supports mechanistic de-risking in preclinical and translational neuroscience by providing a clinically relevant system for evaluating therapeutic interventions targeting secondary injury pathways in severe brain injury. Its flexibility and reproducibility enhance predictive confidence in target validation efforts for neuroprotective compounds.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Scientific Value: Enables interrogation of therapeutic hypotheses by correlating multimodal physiological readouts with pharmacological interventions in a disease-relevant system.
- Operational Value: Provides quantitative, real-time data on intracranial hemodynamics and metabolism to de-risk target engagement and pathway modulation.
Screening & Assay Development
- Scientific Value: Supports assay standardization through consistent probe placement and depth control, ensuring reproducible multimodal outputs across experimental conditions.
- Operational Value: Facilitates preparation of validated biological systems for downstream compound screening by establishing a secure, flexible monitoring platform.
Translational & Preclinical Research
- Scientific Value: Bridges discovery and preclinical validation by enabling continuous monitoring of key pathophysiological processes in a clinically aligned model.
- Operational Value: Supports risk-adjusted advancement decisions by delivering multimodal safety and efficacy readouts that reflect clinical monitoring standards.
Pipeline & Workflow Integration
The method integrates into the discovery continuum from target validation through preclinical research, offering a reusable platform for mechanistic assessment of neurotherapeutic candidates.
- Discovery Biology: Supports hypothesis testing and pathway clarification by enabling simultaneous tracking of pressure, oxygenation, flow, and electrical activity as interconnected biomarkers of brain tissue homeostasis.
- Screening: Enhances assay readiness through standardized, secure probe fixation that minimizes signal drift and artifact during longitudinal compound evaluation.
- Analytics: Generates quantitative, time-synchronized measurements of intracranial pressure, brain tissue oxygen, cerebral blood flow, and electroencephalographic activity to enable multivariate analysis of intervention effects.
- Translational Research: Promotes preclinical continuity by mirroring clinical multimodality monitoring practices used in neurocritical care.
- Enterprise Reuse: Represents a scalable, adaptable capability for repeated use across multiple studies and compound series, reducing redundant procedural development.
Operational & Enterprise Impact
- Scientific Value: Predictive confidence through mechanistic de-risking of targets involved in secondary brain injury pathways.
- Operational Value: Standardization and reproducibility via locked probe positioning and strain-resistant securement.
- Strategic Value: Improved go/no-go decisions by providing multimodal efficacy and safety signals that reduce late-stage biological risk in CNS drug development.
- Portfolio Impact: Enables risk-adjusted prioritization of neuroprotective candidates based on concordant shifts in physiological parameters.
Implementation Considerations
- Requires expertise in neurocritical care monitoring and stereotactic probe placement to ensure accurate depth and trajectory.
- Depends on access to a cranial drill, multimodality probes (ICP, PtiO2, CBF, EEG), and a quad-lumen bolt system.
- Necessitates cross-team standardization between neurosurgery, neurology, and research staff for consistent probe zeroing and data synchronization.
- Involves adaptation considerations when applying to different animal models or varying probe types while maintaining sub-centimeter inter-probe spacing.
- Limited by the need for meticulous securing of probes to prevent displacement during patient movement or elevated intracranial pressure.
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Chapters in this video
0:04
Title
0:31
Patient Positioning
0:48
Site and Skin Preparation
1:18
Equipment Preparation
2:24
Drilling the Burr Hole
3:16
Cranial Bolt Insertion and Probe Securing
4:35
Results: Representative Clinical and Radiologic Multimodality Monitoring Probe Placement
5:40
Conclusion
