Medical robotics - Équipe Automatique Vision et Robotiqueeavr.u-strasbg.fr/~bernard/education/houston/slides_atlantis_cami.pdf · Medical robotics - Design B. Bayle, ... Next generations

Medical roboticsDesign

J. Gangloff – B. Bayle, University of Strasbourg

Medical robotics - Design B. Bayle, University of Strasbourg

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Outline

Introduction : how can robotics help surgery ?

Prehistory

Medical robot design workflow

Environmental constraints

Which architecture ?

About safety

Next generations of medical robots

Futures directions and technical challenges

Conclusion


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Outline


Prehistory




About safety



Conclusion


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Introduction

How can robotics help surgery ?


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Introduction

How can robotics help surgery ?

Accurate positioning using preoperative or peroperative registration

Accurate path following (bone milling, skin harvesting)

Solving the hand-eye coordination problem

Real-time integration of operative data (motion compensation)

Constraining the instrument position in a safe area

Heavy tools manipulation (gamma source for radiotherapy)

Hand tremor compensation

Motion scaling (microsurgery)

Operations in hazardous environment (interventional radiology)

Long distance surgery ?


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Outline


Prehistory




About safety



Conclusion

1985 1989 1992 1994 1998 2001

NeurosurgeryPuma 260Kwoh et al.22 patients

NeurosurgerySpeedy (AID robot)

Lavallée, Benhabid et al.Hundreds of patients

Orthopedic surgeryROBODOC (ISS)

Still in use: >70 robots, over 10000 patients

MISAESOP

(Computer Motion)> 400

MISZeus

(Computer Motion)

MIS + Tele-surgery (IRCAD)

“Operation Lindbergh” New York-Strasbourg

MIS Da Vinci (Intuitive Surgical)Still in use: > 200

TransUrethral Res. of Prostate Puma 560

(Imperial College)

(revisited from J. Troccaz, UEE 2003)

Tele-echographySYTECH (LVR)

Bourges-Kathmandu

Prehistory of medical robotics


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Outline


Prehistory




About safety



Conclusion


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Analysis

Description of the manual procedure

Which improvements expected from the robot ?

(real benefits for the patient/surgeon/hospital/society ? If no, give up)

Can the technology state of the Art address the problem ?

Robotic design

Specifications with medical staff

Derive robotic specifications

Architecture synthesis, CAD design, 3D simulations

First prototype → surgeons corrections → next prototype ...

… Iterate until you find the best compromise

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Robotic specifications

Workspace

Degrees of freedom (external/internal/constraints)

Efforts (forces and torques)

Velocities, accelerations

Accuracy, repetability

+ Actuation and instrumentation (motors, sensors, control strategy)

+ Human-Machine Interface

Constraints

Access to the operation area (medical technique : MIS, NOTES, ...)

Safety (avoidance of anatomical structures, intrinsic safety)

Sterility (procedure)

Compatibility with the OP room (transportability, size)

Compatibly with other devices (imaging system, radiotherapy, ECG)

Human factor (acceptance by the patient and/or the medical staff)


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Choices

Architecture: type synthesis (serial or parallel + joint arrangement)

Singularities

Joint limits

Actuators (DC, DC brushless, piezo, pneumatic, ...)

Sensors (absolute/incremental encoders, force sensors, acceleration sensors, visual sensors, …)

Materials (metal, biocompatible material, …)

Control strategy (robustness, predictive or repetitive control)

Human-machine interface (mouse/keyboard, touchscreen, voice recognition, gaze tracking, joysticks/haptic interface)


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Outline


Prehistory




About safety



Conclusion


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Environmental constraints : Minimally Invasive Surgery

Widely used technique in abdominal surgery and also now in cardiac surgery

Difficulties :3 hands are necessaryMonocular visionPosition of the surgeonHand-eye coordination (fulcrum effect)No force feedback + friction at the trocartLoss of mobility due to the trocarLimited workspaceVisual field occlusionsPhysiological motionsCritical areas


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Environmental constraints : coronary artery anastomosis

Medical specificationsØ 2 mm, 10 to 20 stitching pointsØ suturing thread : 0.1 mmStitching force: up to 1NResolution: better than 0.1 mmTask : stitching + knot tying

graft

Suture of a graft on a coronary artery

Difficulties Accurate force-controlled motionSoft-tissue interactionPhysiological motionsComplex geometry of the working area+ all the difficulties linked to MIS if it is done this way


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Environmental constraints : interventional radiology

Interventional radiology Biopsy, tumor ablation,stents Image-guided needle or catheter insertion

(CT, MRI) High doses of radiation

Difficulties Mental registration of the needle position with respect to the patient anatomy, Accurate control of the insertion force during the crossing of tissues of various stiffness Physiological motion compensation Critical areas avoidance


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Outline


Prehistory




About safety



Conclusion

҉ Robotics Basics

Actuator = motor

Axis = joint

Body = link

End effector

Base

҉ Robotics Basics

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Robot = multi-joint mechanical system

Prismatic joint (T-joint)

Revolute joint (R-joint)

Geometry

Joints number

Type: serial or parallel

Joint arrangement

Number of degrees of freedom (DOF)

҉ Robotics Basics

Workspace = reachable volume for the end effector. Depend on :

Robot geometry

Links lengths

Joints limits


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→ end of the 90s : medical robot adapted form industrial robots : typically anthropomorphic or SCARA robots

Anthropomorphic robot :Holder (3 DoF) + wrist (3 DoF)Workspace ~ sphere

Tx, Ty, Tz Rx, Ry, Rz

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→ end of the 90s: medical robot adapted form industrial robots : typically anthropomorphic or SCARA robots

SCARA robot :4 DoF + possible 1-2 DoF wristWorkspace: cylinder

Tx, Ty

Tz

Rz

Rx, Ry

Workspace well suited to a patient lying on the OP table Less sensitive to gravity → safer in case of power failure

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Anthropomorphic & SCARA examples

Hippocrate (LIRMM, Montpellier), 1998 Dermarob (LIRMM, Montpellier), 2003

1 similar at IRISA Rennes for echography

1 similar at LSIIT, Strasbourg for beating heart surgery

CASPER (TIMC, CHU Grenoble)

Pericardic punction with PADyC robot

Robot with passive mechanism that constraints the tool motion to avoid critical areas

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Dermarob 1998-2003, LIRMM Montpellier

Skin repair surgery for severe-burn patients 2 stages procedure :

skin harvestinggrafting

Issues : important efforts and accuracy Constraints : constant skin thickness, avoid holes Automated harvesting

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v

DMS footpedal

Userinterface

Dermatomecontroller

Controlcabinet

6 DoF SCARA robot with non spherical wrist Mobile platform 6 DoF force sensor, laser range finder Hybrid force and position control

z0z1z2 z3 z4x5x6

z6

z5

x0x1x2x3

D3D4

D6x4

R4

z

y xϕθ

ψ

D3 = 400 mmD4 = 400 mmR4 = 200 mmD6 = 200 mm

Wrist singularity out of the workspace

Dermarob 1998-2003, LIRMM Montpellier

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Parallel robot example

Stiffness, accuracy, acceleration, lightweight, load/weight ratio Complex model, singularities, small workspace

… traditional architecture of haptic interfaces

Surgiscope, ISIS


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2000 → now : medical robot designed for specific tasks

Frequent properties :

Number of DoF limited to the task achievement

Often : fixed point (environmental) constraint (trocar, needle)

Often : tool raw positioning

Very often : tool orientation with spherical workspace

Sometimes : tool translation or translation+rotation


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First problem : going through the trocarRemote Center of Motion architectures (RCM)

Surgical tasks with fixed point constraint : Minimally Invasive Surgery (MIS) Echography Percutaneous needle insertion


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First problem : going through the trocarRemote Center of Motion architectures in MIS

Da Vinci (Intuitive Surgical), 1999

ZEUS (Computer Motion), 1998ZEUS (Computer Motion), 1998

Active RCM

Passive RCM

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First problem : going through the trocar

MC2E – Manipulateur Compact de Chirurgie Endoscopique (LRP, Paris)

EndoXiroB (Sinters), 2004

RCM architectures

c : manipulation directe du trocart

b : manipulation de l’instrument

a : dispositif de base

Friction compensation devices


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First problem : going through the trocar

MC2E – Manipulateur Compact de Chirurgie Endoscopique (LRP, Paris)

EndoXiroB (Sinters), 2004

RCM architectures

c : manipulation directe du trocart

b : manipulation de l’instrument

a : dispositif de base

Friction compensation devices


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Second problem : need of a third hand

(LER, Light Endoscopic Robot, TIMC, Grenoble)

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Third problem : lack of internal mobility

Disposable plastic wrist (LAAS, Sinters 2004)plastic vertebra+balls and NiTi super-elastic wires

Modular instrument (LRP), 2003

Micro-robot for endoscopy (INRIA), 2003

Wrist of C. Reboulet (ONERA), 1994


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Outline


Prehistory




About safety



Conclusion

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About safety

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About safety

Problems

Robot shares its workspace with the medical staff and with the patient

Trial and error approach is not allowed

Sterility constraint

Compatibility with other medical devices

Some solutions

Intrinsically safe mechanical design : lightweight, limited power, slow motion, workspace suited to task, passive limits

Redundancy of sensors : incremental and absolute encoders, collision detectors, force sensors, hardware self-check sensors

High-quality software : fault tolerant programming language, redundancy of computers, quality certified programming

Safe human interface : simple to use, easy to understand, important function easily and quickly accessible


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Outline


Prehistory




About safety



Conclusion

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Difficulties

Complex geometry

Registration of cutting planes, boring axis, ...

High accuracy

Force control

Next generations of medical robotsExample : orthopedic surgery

Tibial cutTibial cut

Femoral cuts cuts

Total Knee Arthroplasty (TKA)

+

Total Hip Arthroplasty (THA)

Milling/boring

Cutting

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ROBODOC (ISS), 1992ROBODOC (ISS), 1992

CASPAR (OrtoMaquet), 1997

CRIGOS (Helmholtz-Institute/TIMC), 1997

Table-mounted robots + navigation systems

ACROBOT (Imperial College/Acrobot Ltd), 2001

BRIGIT (MedTech, LIRMM), 2005


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Praxiteles (TIMC): TKA

Patient-mounted robots

Small size / footprint – minimal obstruction

Proximity of the surgical site

No firm immobilization of the patient

No real-time tracking / repositioning

Small workspace – fine positioning system

Potentially more accurate

Intrinsic safe due to the small weight and power

Robotized spacer for ligament balance in TKA (TIMC, Grenoble)


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Some trends

Technical challenges for new medical procedures

Diagnostic and therapy of smal intestine

Microsurgery

Neuroendoscopy for treatment of back pain

Totally endoscopic beating heart surgery

NOTES

Biomicromachines

Technical challenges to improve existing procedures

Smaller, simpler, smarter and cheaper robots

More integrated systems “plug and play”

More immersive human-machine interface

General trend : robots dedicated to the task


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Some solutions currently investigated

MARS (Technion/Mazor Surg), 2002: spine surgery

Patient mounted robot

Smart instruments for simple dedicated tasks (rather than multi-purpose robots)

MICRON tremor cancelling instrument (CMU, Pittsburgh): eye surgery


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Outline


Prehistory




About safety



Conclusion


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MALICA (LIIA, Paris XII): aneurysm repair

Active catheter for stent placement

Snake like hydraulic robot : 2 DoF,

Ø 5mm x 20mm

Futures directions and technical challenges :active catheters

MINOSC (EU project coordinated by SSSA, Pisa): precise and early diagnosis of spinal chord lesions

Endoscopy of the spinal cord: navigation in the cerebro-spinal fluid with micro-jets to avoid touching tissues


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HeartLander (CMU, Pittsburgh)

Inchworm-like robot for beating heart surgery

Futures directions and technical challenges :intra-cavity mobile robots

The Endoscopy « Pill » M2A(Given Imaging), 2001

EMIL (SSSA, ARTS Lab., Pise)


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Outline


Prehistory




About safety



Conclusion


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Conclusion

To be improved :

Benefits/(costs x complexity ) ratio should be increased

Technical staff in the OP room

Simpler training for the surgeons

Operation time should be at least similar than conventional operation

Reduce overall costs for the hospital (maintenance, training)

Long-term benefits should be proven

Installation and use should be simpler

Safety

► Still lot of work : improve interaction surgeons / engineers


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Examples

Robot attached to the patient Workspace : half-sphere of 15cm radius 3 DoF for entry point positioning and 2 DoF for the

needle orientation Segments made of plastic to be CT compatible Ultrasonic motors for compactness Insertion force up to 20N 1.5 Kg

CT-BOT (LSIIT, Strasbourg), 2003

CT/MRI compatible biopsy robot (TIMC), 2004

5 DoFPneumatic actuators1 KgMade of polymer

Poser sur le patient compensation des mouvements du patient et de la respiration

Medical robotics - Équipe Automatique Vision et Robotiqueeavr.u-strasbg.fr/~bernard/education/houston/slides_atlantis_cami.pdf · Medical robotics - Design B. Bayle, ... Next generations

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