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Computer Assisted Orthopaedic Surgery (CAOS)

Navigation in Hip Fracture

Source: http://www.stryker.com/navigation/us/trauma/apps.htm

Chau Pui Man, Jasmine, Registered Nurse, Department of Anaesthesia & Intensive Care (Operating Theatre), Prince of Wales Hospital, Hong Kong

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The Development of CAOS

1st performed by Prof. K. S. Leung in 2001 SeptTotally more than 300 operationsLeading positionRoutine orthopaedic practice, especially in fracture fixation Different from CAOS in total joint arthroplastyIncreasing demands on perioperative nurse

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Applications of CAOS in fracture fixation surgery

Fixation of femoral neck fractures with percutaneous cannulated screwIntramedullary locked nails for long bone fracturesIntramedullary fixation of trochanteric fractures e.g. Gamma nailsPercutaneous fixation of sacro-iliac fracture dislocations (SI joint screw)Percutaneous fixation of iliac wing fracturesPercutaneous fixation of acetabulum fractures

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Types of Navigation for surgical planning

Image-guided navigation1. CT, MRI based

Intra-op registration of anatomical landmark that correspond to pre-op CT scan

2. FluoroscopyMake use of C-arm fluroscope to create images in operating room

Image-free navigationIntra-operative determination of anatomical structures and reference landmarks to establish a virtual representation of the surgical object

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How to localizing target within the operating room?

Principle of tracking systemInfra-redElectromagnetic wave Ultrasound andLaser

Most commonly used technique is infrared optical tracking system

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Essential Equipments and Instrument

Source: http://www.stryker.com/navigation/us/trauma/apps.htm

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The Computer Workstation with Monitor

Localize Camera

Computer monitor

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Fluoro Machine System (Siemens)

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Robotic arm (Surgical navigation arm)

The strength of robots includes:

1. Precision2. Stability 3. repeatability

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Tracking Devices

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Phantom and C-arm tracker

Phantom

LEDs

Phantom attached on the C-arm tracker to correct image distortion. The C-arm tracker is located with the LEDs.

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Basic Instrument

Extension pin

Anchoring pins

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Specifically designed axis adaptor

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Tool Assembly

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Technique of Fluoro-NavigationFour basic steps

1. (Referencing): The patient tracker is anchored to the part of the bone that is going to be operated

2. (Tracking): The surgical instruments are fitted with tracking sensor

3. (Image acquisition and transfer): Images are taken using the C-arm and loaded into the navigation computer

4. (Navigation): The surgical instrument is displayed as a virtual instrument in the medical images in real time

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Workflow of computer Infrared optical tracking navigation system (image-guided)

Patient tracker anchored on anterior iliac crest

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Calibration of surgical instrument

Calibration device

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Image acquisition (AP/Lat view)

C-arm tracker calibration

AP view

Lat view

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Skin incision planning

The camera receive the signal then the computer recognize the signal

The result is shownon the computer screen

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Lag screw position planning

Lag screw length measurement Virtual lag screw position

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Operation Room Layout (Hip fracture)

Fluoro machine

Sensor/camera

Monitor/screen Computer System

Patient Tracker

Fluoromonitor

The operating room should be of adequate size to accommodate the fluoro unit, fluoro monitor and the computer system

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Fluoroscopic navigation

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Iso-C 3D navigation

Solid carbon table

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Advanced Practice Nursing RoleOrthopaedic team nurses- Have expert clinical skills and knowledge- Have thorough understanding of how equipment

function, distinguishing between a device failure and user error

- Quick response in the complexity of new devices, their application and integration with traditional instrument

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Advanced Practice Nursing Role

Circulating Nurse2 circulating nurses – one for operating the computer, one for providing patient care

Scrub Nursewell familiar with the navigation instrument

Formation of a surgical team dedicated to CAOS

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Enhancement

Departmental training and educationProtocols and procedure guidelines Organize one day course Nurse teleconference on live demonstration Active participate in live surgery Design in the theatre layout Virtual lab study in Orthopaedic Learning Center

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Virtual Lab

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