biology

Neuronavigation

Neuronavigation is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Neuronavigation rather than just read about it. In short: Neuronavigation is the set of computer-assisted technologies used by neurosurgeons to guide or "navigate" within the confines of the skull or vertebral column during surgery, and used by psychiatrists to accurately target rTMS (transcranial magnetic stimulation). The set of hardware for these purposes is referred to as a neuronavigator.

Key takeaways

Neuronavigation belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Neuronavigation to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Neuronavigation from memory before moving on to harder problems.

Reference excerpt

Neuronavigation is the set of computer-assisted technologies used by neurosurgeons to guide or "navigate" within the confines of the skull or vertebral column during surgery, and used by psychiatrists to accurately target rTMS (transcranial magnetic stimulation). The set of hardware for these purposes is referred to as a neuronavigator.

Stereotactic surgery Neuronavigation is recognized as the next evolutionary step of stereotactic surgery, a set of techniques that dates back to the early 1900s and that gained popularity during the 1940s, particularly in Germany, France and the U.S., with the development of surgery for the treatment of movement disorders such as Parkinson's disease and dystonias. In its infancy the purpose of this technology was to create a mathematical model describing a proposed coordinate system for the space within a closed structure, e.g., the skull. This "fiducial spatial coordinate system” uses fiducial markers as a reference to describe with high accuracy the position of specific structures within this arbitrarily defined space. The surgeon then refers to that data to target particular structures within the brain. This technology was boosted by the collection of data on human anatomy in “stereotactic atlases”, expanding the quantitatively defined “targets” that could be readily used in surgery. Finally, the advent of modern neuro-imaging technologies such as computed tomography (CT) and magnetic resonance imaging (MRI)—along with the ever-increasing capabilities of digitalization, computer-graphic modelling and accelerated manipulation of data through complex mathematical algorithms via robust computer technologies—made possible the real-time quantitative spatial fusion of images of the patient's brain with the created “fiducial coordinate system” for the purpose of guiding the surgeon's instrument or probe to a selected target. In this way the observations done via highly sophisticated neuro-imaging technologies (CT, MRI, angiography) are related to the actual patient during surgery.

Neuro imaging The ability to relate the position of a real surgical instrument in the surgeon's hand or the microscope's focal point to the location of the imaged pathology, updated in "real time" in an "integrated operating room", highlights the modern version of this set of technologies. In its current form, neuronavigation began in the 1990s and has adapted to new neuro-imaging technologies, real-time imaging capabilities, new technologies to transfer the information in the operating room for 3-D localization, real-time neuro-monitoring, robotics, and new and better algorithms to handle data via more sophisticated computer technology.

Surgical virtualization In its later conceptualization, the term neuronavigation has started to overlap with surgical-virtualization in which a neurosurgeon is able to visualize the scenario for surgery in a 3-D model of manipulable computer data. In this way the physician can "practice and check" the surgery, try alternative approaches, assess possible difficulties, etc., before the real surgery takes place.

Neuronavigation for transcranial magnetic stimulation The standard TMS protocol which was FDA approved in 2008 estimates the location of the DLPFC by finding the left motor cortex and marking a spot 5 cm anterior to it. Later two more methods were introduced using measurements of the head and calculating the location of the DLPFC as 1) the F3 (EEG 10/20 system) or 2) the Beam method. Both were estimations with some limitations. With the introduction of Neuronavigation, direct visualization of structures can be achieved either with an individual's (specially ordered) MRI or an average brain (MNI) stretched to the dimensions of the individual. There is now greater significance of this increased accuracy due to recent evidence that stimulation of the gyral crown is less effective than stimulation of the sulcal bank. The introduction of robotic controlled TMS also may make Neuronavigation more important. Several manufacturers offer complete systems including Ant Neuro or Axilum Robotics.

Neuronavigation for spine surgery Assistive technologies are used during spinal fusion surgery to increase accuracy, especially for the placement of pedicle screws. A review of navigation techniques for spine surgery published in 2019 listed four currently available options:

Medtronic stealth system BrainLab Stryker navigation 7D Surgical system

External links American Association of Neurological Surgeons (AANS.org) | Library. Research List. Neggers SF, Langerak TR, Schutter DJ, et al. (April 2004). "A stereotactic method for image-guided transcranial magnetic stimulation validated with fMRI and motor-evoked potentials". NeuroImage. 21 (4): 1805–17. doi:10.1016/j.neuroimage.2003.12.006. PMID 15050601. S2CID 25409984.

References

Illustrations

Worked examples

Example 1 — a first encounter with Neuronavigation

Start with the simplest possible case. Write down what Neuronavigation claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Neuronavigation before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Neuronavigation ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Neuronavigation

In research: Neuronavigation appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Neuronavigation in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Neuronavigation is common in secondary-school and first-year university syllabi. It links to neighbouring topics Neurosurgery, so understanding it makes those chapters shorter.
In everyday life: Look for Neuronavigation outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Neuronavigation in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Neuronavigation means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Neuronavigation out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Neuronavigation in simple terms?

Why does Neuronavigation matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Neuronavigation?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Neuronavigation.