WEBVTT
Kind: captions
Language: en

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- I'm taking a couple of
weeks off and while I'm gone,

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some brilliant people are
standing in for me here.

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First is Alex from Brainbook,
he's a brain surgeon.

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There's nothing gruesome in this video,

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but there is the answer to a
question I never knew I had,

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how do neurosurgeons find their
way around inside the brain?

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- Neurosurgery is fraught with risk.

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The brain is packed with
almost 100 billion neurons

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compartmentalised into
complex bundles of nerves

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and other structures that
make you who you are.

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Small parts of your brain
are vital for allowing you

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to speak, move, think, learn and love.

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As neurosurgeons, we operate in and around

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these vital structures and
spend a great deal of time

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learning the anatomy so
that we can operate safely.

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The room for error can be millimetres

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as we manoeuvre around blood
vessels and critical nerves

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and damaging any of these can
cause either life changing

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or life ending complications.

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No matter how good the
surgeon and no matter

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how good their knowledge,
we can still go astray

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and need a helping hand.

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Neurosurgery is a
specialty that's inherently

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intertwined with cutting edge technology,

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and we can use that to guide us

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when we're navigating the brain.

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Today I'm going to show
you how neurosurgeons

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can use infrared and electromagnetic
image guidance systems

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to show us exactly where
we are in the brain

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during critical operations
like brain tumour surgery,

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or inserting biopsy needles
deep into the brain.

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This is a Medtronic StealthStation S8.

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It's a combination of
hardware and software

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that uses special trackable instruments,

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such as this pointer and this stilette.

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To be able to guide the neurosurgeon,

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the system tracks the
position of these instruments

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in relation to the surgical anatomy

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and sends that information
to the software.

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The software then displays
the instrument's position

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on either the CT or MRI
scan of that patient.

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The system can track
instruments either optically

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using an infrared camera
or electromagnetically.

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With optical tracking,
this camera sends out

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and then detects infrared light

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that's reflected from these silver balls.

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The camera then transmits
the instrument's location

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to the navigation software.

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Similarly, with electromagnetic tracking,

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the emitter emits a low
energy magnetic field

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with unique characteristics
at every point.

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The electromagnetic
instruments contain sensors,

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which allow the navigation software

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to identify the instrument's location 
within the electromagnetic field.

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For the software to display
the instrument's location

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in relation to images of
the patient, you've got

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to help the software by creating a map

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between points on the patient
and points in the images.

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This process is called registration,

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and it's essentially the
same for both optical

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and electromagnetic types.

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After registration is
complete, whenever the surgeon

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touches a point on the patient
using one of these tracked instruments,

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the computer uses the map

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to identify the corresponding
point on the images.

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This identification is called navigation.

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And now I'm going to show
you both systems in action.

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Here we've got an MRI
scan of a brain model

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that we're going to use.

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Coming up, you see this
white blob, which is supposed

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to be a simulated brain
tumour on the MRI scan.

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Up here, you can see an
eye coming into view,

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and then the nose.

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So this is the brain that's going to
correspond with the model.

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In the bottom right hand corner,
we're using infrared tools,

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and you can see the pointer
coming into reference

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with the reference array
that we've got fixed

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to the patient's head.

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We're going to be doing
registration as we mentioned before,

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marking out lots of points
with the infrared pointer.

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Now we can verify the registration.

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We've got 1.5 millimetre accuracy,

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which will do for this simulation.

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So, we're going to touch the
tip of the nose on the model

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and you can see in the MRI
that that correlates well.

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Let's look at the inner part
of the eye and that looks good.

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The outer part of the eye
and the tip of the ear,

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and this is all looking like

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it's corresponding really nicely.

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We put the pointer into
this hole that's pre made,

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we're on the tumour, so
that's looking good as well.

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And this is a pre made craniotomy
or trapdoor in the skull

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that's going to allow us to just
access the tumour straight away.

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In real life, we'd make this hole

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and that would take about
45 minutes to an hour,

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having cut through the skin
and drilled off this bone.

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So we can operate around
this tumour and see exactly

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where we are in the brain
avoiding critical structures

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like blood vessels, nerves
and parts of the brain

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that are important for speaking
and seeing, for example.

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Now let's move on to the
electromagnetic form of navigation,

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which is also called axiom guidance.

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We're going to be using a
Rowena neurosurgical simulator

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and thanks a lot to
Susie Glover from Delta

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and Stephanie Brown from
NHS Healthcare Horizons.

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This model is quite cool because it
actually has fluid systems within it

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and here you can see
us actually scanning it

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and we're going to take these CT images
and plug them into the software.

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Here you can see we've
put the model in pins,

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but we don't usually do that
because it can interfere

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with the electromagnetic system.

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We're going to be using
this stilette to guide

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a piece of tubing deep into
the brain's fluid reservoirs.

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This pointer is what we're going to use
to do a registration.

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This is the actual catheter
that we're going to be inserting

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deep into the brain and we'll take out

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the little metal stilette
that comes with it,

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and insert the tracked axiom stilette

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that comes with the
electromagnetic system.

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So now that catheter is
tracked, we can use this pointer

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to mark out exactly what
trajectory we're going to be using

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and see where we're going
to need to make a cut

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and then later on where we're
going to make a burr hole

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which is a small hole in the skull

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that allows us to access the brain.

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Now we're going to mark it
with a red marker in this case

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and start drilling.

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[high speed drilling]

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Once we've made the hole
and done a bit more work

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in real life, we're ready
to put the catheter in.

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On the right so you can see
that the StealthStation

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is showing us how far we need
to go and shows us a target

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that we've pre-planned.

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We're going to follow that trajectory

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and make sure the green dots line up.

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As we advance the catheter down,

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it gives us a countdown in millimetres.

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Once we reach zero, we should
be in the ventricle system

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and as I take out the metal
stilette from inside the tubing,

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fluid should start coming out.

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And there we are, we are in.
And in real life

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we'd now secure this catheter
and get out of there.

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- Go and subscribe to Brainbook,
start with his video

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on a day in the life of
a neurosurgeon on call.

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Next week, we go from brain
surgery to settling on Mars.