Robot for Skull-Base Surgery · Robot for Skull-Base Surgery. Neurosurgery • Commercially available systems (eg.Neuromate, Robodoc, Acrobot) are lacking in the degrees of freedom

By: Charles Lo Vui Hong

Robot for Skull-Base Surgery

NeurosurgeryNeurosurgery

•• Commercially available systems Commercially available systems ((eg.Neuromateeg.Neuromate, , RobodocRobodoc, , AcrobotAcrobot) are ) are lacking in the degrees of freedom required lacking in the degrees of freedom required for skull base surgeryfor skull base surgery

•• Large workspace leads to unconstrained Large workspace leads to unconstrained motion that may pose a danger to patient motion that may pose a danger to patient and surgeonand surgeon

Introduction to Skull Base SurgeryIntroduction to Skull Base Surgery

Involves drilling of the temporal boneInvolves drilling of the temporal boneTo access deep seated skull base tumorsTo access deep seated skull base tumorsOne of the longest operations in One of the longest operations in

neurosurgery(8neurosurgery(8--13 hours)13 hours)

Posterior Cranial Posterior Cranial FossaFossa7th & 8th Nerves

CerebellopontineAngle

CerebellumSigmoid Sinus

Cochlea

Semicircular Canals

Mastoid

Acoustic Acoustic NeuromasNeuromas

Medium-sized Acoustic Neuroma

Common Surgical ApproachesCommon Surgical Approaches

TranslabyrinthineTranslabyrinthine ApproachApproach

Skull Base SurgerySkull Base Surgery

System ModulesSystem Modules

NeuroBotNeuroBot SystemSystem

NeuroBaseNeuroBase NeuroPodNeuroPod NeuroVisionNeuroVision NeuroRaTNeuroRaT

Robot Controller

Base Structure

Manipulator

7th DOF

Drill Unit

Force Sensor

VolumeVisualization

Robot UserInterface

Path Planning

TrackingDevice

PatientMarkers

RobotMarkers

DigitizingProbe

SurgicalNavigation

SurgeonSurgeon

Robot User Interface

Multi-Modal Images

3-D Images

Path-Planning

NeuroVisionNeuroVisionCT/MRI/MRA

Images

DextroScope

NeuroPodNeuroPodForce Feedback

HexapodHexapod

7th DOF

Drill Unit

NeuroBaseNeuroBase

Robot Controller

Base StructureBase Structure

Proposed SystemProposed System

Patient Tracking

Robot Tracking

Surgical Tool Tracking

Surgical Navigation

NeuroRATNeuroRAT

PatientPatient

Registration ErrorsRegistration Errors“During patient registration, surgeons strive to

minimize a number provided as feedback by the registration system. Unfortunately, this measure of error is merely an estimate of the accuracy of the

rigid body transformation. This estimate informs the operator only of error in the geometric alignment of the fiducial markers registered. Reliance on this

number as a proxy for the accuracy of the computer-assisted navigation during sugery is naïve

at best. At worst, the values may be misleading, especially with respect to the target registration error (TRE) which is of paramount importance

clinically.”

Physical Space {P} Image Space {I}

Combined Space

Fiducial Registration Error

(FRE)

After Registration

Physical Space {P} Image Space {I}

Combined Space

After Registration

Target Registration Error(TRE)

Sub-Module: Patient Markers

NeuroRATNeuroRAT

NeuroRATNeuroRATSub-Module: Digitizing Probe

NeuroRATNeuroRAT

NeuroPodNeuroPod

Sub-Module: Manipulator Description:Description:

6 axis parallel 6 axis parallel kinematickinematic robot (Hexapod)robot (Hexapod)

•• micron resolutionmicron resolution• small workspacesmall workspace•• high stiffnesshigh stiffness(Fraunhofer-Institut Produktionstechnick and Automatisierung)

Function:Function:

To move drill unit along a specified drill trajectoryTo move drill unit along a specified drill trajectory

Workspace Analysis

Workspace Analysis

⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥

⎦

⎤

⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢

⎣

⎡

=

maxmaxmax

minmaxmax

maxminmax

minminmax

maxmaxmin

minmaxmin

maxminmin

minminmin

ψθφψθφψθφψθφψθφψθφψθφψθφ

G

Iteration 1

Iteration 2

Iteration 7

Workspace Analysis

Iteration 8

Iteration 12 Iteration 28

Iteration 32

Iteration 2

NeuroBaseNeuroBase –– 11stst PrototypePrototype

Description:Description:

Hybrid parallel serial system with Hybrid parallel serial system with decoupled motionsdecoupled motions

Function:Function:

To place To place NeuroPodNeuroPod rigidlyrigidly in optimum in optimum working volume to maximize use of working volume to maximize use of Hexapod’s workspaceHexapod’s workspace

{B}

{T}

{H}

{W} Optotrak

Base Robot

Hexapod

Bone-RemovalTool

A = RpbAt = bAh

hAt

Robot RegistrationRobot Registration

{W}

{M}

pimpi

wpm

wpi

Markers

Path / Task-Envelope

S

I

R

L

P

A{M}

{V}

pimpi

vpm

vpi

Skull-Base

Markers

Point on Path’sBoundary

(Offset View)

Virtual ReferenceFrame

mPe = vPe - vpmwhere P = [pi, pi+1, …, pn]T

{T}

Hexapod

Bone-RemovalTool

{W}

pi

tAe

wAt

wAe

Path / Task-Envelope

{E}

{B}

{T}

{E}tAe

bAt’

bAteAf

Best Fit PosebRt’ eRfbpt’ epf

SubSub--Module: Module: Path PlanningPath PlanningManual (Manual (DextrascopeDextrascope))

CONSTRAINT TASKCONSTRAINT TASK--ENVELOPEENVELOPECONSTRUCTION (CONSTRUCTION (CONTECCONTEC))

Target Spot

Critical Bounds

General Direction of Action

Encapsulating Matrix/ Medium

Problem Formulation and Representation

SubSub--Module: Module: Path PlanningPath PlanningAutomatic (CONTEC)Automatic (CONTEC)

SubSub--Module: Path Planning (1)Module: Path Planning (1)CONTECCONTEC

ri

EiVoronoiVertex

VoronoiSkeleton

Line of Action

D2

D1

l1|m

li-1|m

li|m

li+1|m

ln|m

Line of Action BODm


li|1 li|mli|m-1 li|m+1 li|o

ImD1

D2

Line-of-ActionLine-of-Action

Cavity Bound)(upperθ

)(lowerθ

Target Spot

Slices

Upper Fulcrum Point

Lower Fulcrum Point

θ4


3rd Fulcrum Point

4th Fulcrum Point

θ3


Conduit Vector 1

Conduit Vector 2

Straight Tool

Contact Line of Tool

Inaccessible Areas

PROBLEMPROBLEM

CL1


CL2

ϕ

ϕ

FP4

FP3 FP1

FP2

CL1’

CL2’


ϕ = min ( maxminmaxminmaxmin ,,,,, ψψθθφφ )CL1


CL2FP4

FP3 FP1

FP2

OutlyingPoints

AmendedPoints



Final Boundary

Four main properties are inherent for the constructed conduit:•It avoids all critical areas/bounds;•Allows for maximal line of sight;•Alleviates areas which are inaccessible;•Takes into account the rotational ability of the parallel manipulator.

SubSub--Module: Path Planning (2)Module: Path Planning (2)ABNOABNO



ei-1

ei

ei+1

ei+2

Vi-1

Vi

Vi+1

Vi+2

Vi+3bi

bi+1

bi+2

bi’

Ii

Vi+4

bi+3

ei+1

ei-1

ei+2

ei+3

ei+3Ii+2

VVnn --> e> enn--11 , e, en n ((bbnn))....

IIii --> > eeii--11 , , eei+1i+1 ((bbii’’))

VVii--1 1 --> > eeii--22 , , eeii--11

((bbii--11))

..

..VV11 --> e> enn , e, e1 1 (b(b11))

LAVLAV22

VVnn --> e> enn--11 , e, en n ((bbnn))....

VVi+1i+1 --> > eeii , , eei+1i+1

((bbi+1i+1))

VVii --> > eeii--11 , , eeii ((bbii))

VVii--1 1 --> > eeii--22 , , eeii--11 ((bbii--

11))

..

..VV11 --> e> enn , e, e1 1 (b(b11))

LAVLAV11

List of Active Vertices

eei+i+

33

eei+i+

11

VVi+i+

33

VVi+i+

22

IIi+2i+2

..........eei+i+

11

eeii--

11

VVi+i+

11

VViiIIii

eebbeeaaVVbbVVaaIntersectionIntersectionPtsPts

Priority Queue

Vi+2

Vi+3

X

X

Output SkeletonOutput Skeleton

VaI, VbI




CurvelinearCurvelinear ToolpathsToolpaths

Current StatusCurrent Status►► Grant from Biomedical Research Council of AGrant from Biomedical Research Council of A--StarStar►► Ready for Animal/Ready for Animal/CadavericCadaveric Clinical TrialsClinical Trials►► Feasibility Studies to extend applications to Feasibility Studies to extend applications to

NeuroendoscopyNeuroendoscopy, , StereotacticStereotactic Biopsy, Biopsy, NeuroNeuro--OsteotomiesOsteotomies, Pedicle Screw Placements, , Pedicle Screw Placements, Craniotomies, VP Shunt Insertions, maybe even Craniotomies, VP Shunt Insertions, maybe even stemcellsstemcells implantation!implantation!

Current Members:Current Members:Principal Investigators: Dr. Ivan Ng & Charles LoPrincipal Investigators: Dr. Ivan Ng & Charles LoCollaborators:Collaborators:

Volume Interactions:Volume Interactions:NanyangNanyang Technological UniversityTechnological UniversitySingapore Institute of Manufacturing TechnologySingapore Institute of Manufacturing Technology

Thank You……..Thank You……..

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Robot for Skull-Base Surgery · Robot for Skull-Base Surgery. Neurosurgery • Commercially available systems (eg.Neuromate, Robodoc, Acrobot) are lacking in the degrees of freedom