Seminar in Computer-Assisted Surgery Medical Robotics Medical Image Processing LECTURE 1 Dr. Leo...

Computer-Assisted Surgery Medical Robotics

Medical Image Processing

LECTURE 1

1. What‘s in a surgery

2. Technical tools in CS

3. CAS systems

CAS, Spring 2001 © L. Joskowicz 3

PAST: Cut, then see


PRESENT: See, then cut


FUTURE: Combine, see, minimally cut


How do surgeries proceed?• Diagnosis

– based on physical exams, images, lab tests

• Preoperative planning– determine the surgical approach– elaborate intraoperative plan (path, tools, implants)

• Surgery– prepare patient and assess condition– acquire intraoperative images, adapt and execute plan

• Postoperative follow-up– exams, lab tests, images to be corroborated


Treatment procedures• Invasive

– neurosurgery: tumor removal– hear surgery: clogged arteries, transplants– orthopaedic surgery: spine, hip replacement, knee,

fractures– gall bladder removal, prostate, various cancers

• Non-invasive– radiation therapy– kidney stone pulverization


Medical imaging modalities

• Preoperative– Film X-rays, Digital X-rays, Ultrasound,

Angiography, Doppler, ….– Computed Tomography (CT), Magnetic Resonance

(MR), Nuclear Medicine (PET, SPECT, …)

• Intraoperative– X-ray fluoroscopy, ultrasound– video images (laparoscopy, arthorscopy)– Open MR


Medical imaging modalities: X-rays

Film or Digital X-ray X-ray Fluoroscopy


Medical imaging modalities: continuous X-ray angiography


Medical imaging modalities: Ultrasound


Medical imaging modalities: CT

Single slice

Series of parallel slices 2mm apart


Medical imaging modalities: MRI

Good imaging of soft tissue


Medical imaging modalities: Nuclear medicine (PET, SPECT, NMR)

Functional imaging: colors indicate

electrical activity


Medical imaging modalities: video

TV quality image from small camera (laparoscope or endoscope)


Surgical approaches• Open surgery

– area of interest directly exposed by cutting– direct sight and touch of anatomy by surgeon– direct access but causes additional damage

• Closed surgery not always feasible– indirect access to anatomical area of interest– no direct visual sight or tactile feel– catheterization, biopsies– intraoperative imaging is often required– require more skills: lengthier, more difficult

• Diagnostic surgery


Minimally invasive surgery

• Provides treatment through small incisions

• Uses imaging equipment for seeing and instruments for touching

• Advantages: less damage, faster recovery

• Disadvantages: hand/eye coordination, time

• Examples: – brain tumor removal, laparoscopic surgery


Laparoscopic surgery


Brain surgery


Total Hip replacement -- principle


Total hip replacement procedure


What is required to perform surgery?

• Knowledge intensive task– anatomy, procedures, cases– experience, skills, customization and generalization

• Manual and cognitive skills– dexterity, precision, strength, tool manipulation– spatial orientation and navigation

• Determination– information integration– judgement, decision, execution


Medical and surgical trends• Imaging improved dramatically diagnosis

– started with X-rays last century– 30% of all cases use images

• Move towards minimally invasive procedures– introduced in the mid ‘70s, slow acceptance (laparoscopy)– the method of choice now

• More precise and delicate procedures

• Development of sophisticated surgical hardware

• High degree of craftsmanship and skills


Socio-economical medical trends

• Increase of aging population and associated problems: tumors, osteoporosis, Alzheimers

• Larger population volumes

• Universal, first rate, highly specialized care

• Health care costs reduction (managed care)

• Higher patient requirements

• Legal and regulatory aspects


Surgical Needs

• Support for image-guided surgery• Passive and active devices for accurate spatial positioning,

tracking, and execution• Modeling, planning, viewing, diagnosis systems• Systems integration: from diagnosis to post-op• Improve current practice and enable new procedures• Simulation and training systems

Augment the surgeon’s capabilities with better quantitative planning, execution, and integration


Current clinical status• Imaging

– vast databases of medical images– digitized atlases– mostly uncorrelated unimodal qualitative interpretation

• Devices– mostly passive and non-invasive (supports)– laparoscopic camera, – some real-time tracking

• Planning, modeling, visualization– 3D reconstruction, some registration

Part 2: Computers and Robots

Technology and algorithms

available today


How can computers help?(or are already helping…)

• Image processing– single image: enhancement, noise reduction,

segmentation, quantitative measurements– image stacks: 3D reconstruction, segmentation– image sets: registration, comparison, data fusion

• Planning and simulation– integrate medical images and CAD models– planning and simulation programs

• Computer vision and graphics– camera modeling, image registration, rendering


Image processing


Planning and simulation


Virtual man project -- digital model


How can robots and sensors help?(or are already helping…)

• Robotic devices– passive, semi-active, active devices – instrument and anatomy positioning and holding– cutting and machining

• Real-time tracking – optical, video, electromagnetic devices– navigation tools


Robotic devices


Real-time tracking devicescamera

instrument

Passive markers

Instrument has infrared LEDs attached to it Active markers


Computer-Assisted Surgery (CAS)

A computer-integrated system to enhance the dexterity, visual feedback, and information

integration of the surgeon

Key points:• The goal is NOT to replace the surgeon• A new paradigm for surgical tools• Address a real clinical need• Prove efficacy and cost-effectiveness


Elements of CAS systems


Elements of CAS systems• Preoperative planning

– image acquisition, modeling, analysis, simulation– plan elaboration, tool and prosthesis selection– Output: preop images, 3D models, prosthesis type and

position, navigation and cutting plan

• Intraoperative execution– passive, semi-active, active robot– real time tracking– intraoperative imaging (fluoroscopy, ultrasound)


State of the Art (1)

• Main clinical procedures– neurosurgery: biopsies, tumor removal– orthopaedics: hip and knee replacement, spine, pelvis

and femur fractures– maxillofacial and cranofacial– laparoscopy: laparoscope holders– new fields: dentistry, ophtalmology, prostate

• Mostly rigid structures: bones!!



• Commercial navigation systems– main uses: neurosurgery and spine surgery

• Commercial robotic systems– ROBODOC for total hip replacement– laparoscope arm holders

• Research– very active, very interdisciplinary– a few dozen systems tested in-vitro



• Major players– INRIA Sophia Antipolis, Grenoble, Johns Hopkins,

Brigham Women’s H./MIT, Shadyside H./CMU, Imperial College, many places in Germany and Japan

• Interdisciplinary conferences and journals– started in 1994: MRCAS’94; Orthopaedic CAS

meetings, visualization, etc,– Journals: Computer-Aided Surgery, Medical Image

Analysis


Examples of CAS systems in use

• Image-guided navigation systems

• ROBODOC: Total hip replacement surgery

• LARS: Laparoscopic assistant

• Radiosurgery

Brief overview follows; will be covered in detail later


Image-guide navigation• Purpose

– accurate placement of instruments with respect to imaged anatomy for several procedures

• Problem addressed– provide 3D vision of unseen structures

replace static 2D fluoroscopy or larger openings– improve precision of biopsies, screw placements

• Scope– non-invasive– creates surface model from preop images– registration of images to anatomy by direct contact


Image-guided navigation


Image-guided navigation (2)pedicle screw insertion


Status

• In clinical use

• Over 7,000 neurosurgeries performed with commercial systems

• Gaining popularity in pedicle screw insertion

• Decreased the misplacement rate from 10-40%to 5-18% (clinical study of 700 cases)

• More clinical applications under development


ROBODOC: Total hip replacement• Purpose

– precise machining of cementless hip implant canal

• Problem addressed– complications in canal preparation and implant fixation– improve positioning accuracy and surface finish

• Scope– invasive, numerically controled machining– plan from preop CT, registered via pins– adapted commercial robot– custom bone fixator and bone motion detection


Artificial hip joint


Total hip replacement procedure


ROBODOC: Total Hip Replacement


ROBODOC system diagram


ORTHODOC Planning


ROBODOC robot diagram


ROBODOC robot


ROBODOC procedure


ROBODOC cutting


ROBODOC History

• Developed by IBM Research and Integrated Surgical Systems

• First active surgical robot– 1986: feasibility study– 1989: in-vitro testing of dog system– 1990: 26 dog cases– 1992: development of human system– 1994: first human procedure in Frankfurt– 1995- clinical trials in the US for FDA approval


ROBODOC current status

• Sold by Integrated Surgical Systems

• Over 3,000 cases performed

• 15 systems installed in Germany, 2 in Austria

• Excellent short term clinical results (3 year study)– no fractures, few failures (continue manually)

• Long-term clinical results to be determined– key issue: does the artificial hip last longer?

• Problems: OR time, pin insertion


Laparoscopic assistant: LARS

• Purpose– laparocopic camera holding and precise navigation

• Problem addressed– cumbersome, unintuitive, and unsteady camera

positioning

• Scope– non-invasive intraoperative device – video images interpreted by surgeon

• Benefits– direct camera manipulation; stability, precise targeting


Laparoscopic assistant: LARS


LARS characteristics

• Designed at IBM Research, 1993. Similar commercial devices available (AESOP)

• Custom redundant 7 degree-of-freedom robot

• Holds laparoscopic camera

• Fulcrum motions: no motion at point of entry

• Mouse-like controls on surgical scissors

• Position memory and replay


Stereotactic Radiosurgery• Purpose

– plan and deliver precise radiation doses

• Problem addressed– precise positioning and dosing of radiation to avoid

healthy organ damage

• Scope– non-invasive intraoperative device– active beam postioning and planning– complex preoperative planning based on MRI images– registers preoperative plan with stereotactic frame


Stereotactic Radiosurgery


CYBERKNIFE system


CYBERKNIFE system


Stereotactic Radiosurgery: planning


Stereotactic Radiosurgery

• Developed at Stanford starting in 1992

• Complex 3D radiation plans

• Currently in clinical use

• Frameless procedure under development follow head with markers, video, or

X-rays

• Company Accuray has performed several clinical trials with frameless procedure


Developing CAS systems

• Similarities– understand and address real needs of surgeons– consider established procedures, context, use– work on problems that will make qualitative difference– constant feedback from user; test ideas and prototypes

• Differences– system performace requirements


Developing CAS systems

• understand and address real needs of surgeons

• consider established procedures, context, use

• constant feedback from user; test ideas and prototypes

• system requirements– safety and reliability– fail-safe systems: can always stop and proceed as usual– system integration


CAS systems design cycle• Prototype development

• In-vitro experiments– system refinement

• Cadaver studies– system refinement

• In-vivo experiments– first animal and human trials

• Clinical trials– double blind studies, Hospital and FDA protocols

• Agency approval and commercial release


Summary• Great potential for robots and computers inside

and outside the operating room

• Great research and commercial interest, especially in the past 3 years

• Just the beginning of the road: many things remain to be invented

• Great role for applied computer science:– image processing, geometric planning, registration,

graphics, vision, real-time systems, robotics, etc.

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Seminar in Computer-Assisted Surgery Medical Robotics Medical Image Processing LECTURE 1 Dr. Leo...

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