Virtual RealityLaparoscopic Port Site

Simulator

University of Washington

Department of Surgery&

Human Interface Technology Lab

Mika Sinanan, MDUniversity of Washington Medical Center Department of Surgery

Suzanne Weghorst, MSUniversity of Washington Human Interface Technology Lab

Mark MacFarlane, MDUniversity of Washington Medical Center Department of Surgery

Peter Oppenheimer, MSUniversity of Washington Human Interface Technology Lab

James Cain, MS2University of Washington School of Medicine

Port site placement in laparoscopic surgery is crucial for both the neophyte and experienced surgeon.

Proper trocar placement has previously been designated as an "art form" with few precise guidelines.

PROBLEM

• excessive port entry incisions • increased length of operation• uncomfortable surgical technique• reversed endoscopic view• inefficient manipulation angles• increased instrument collisions• increased risk of infection

Improper trocar locations can lead to...

A virtual reality laparosopic surgical simulator has been developed as a training tool to allow surgeons to experiment with the effects of camera and instrument port placement.

EDUCATIONAL SOLUTION

Objectives of Trial Study

• Determine Optimal Port Placement Characteristics through objective measurement of simulated procedures

• Evaluate the effectiveness of the simulator as a training tool.

Design Issues

• Trial Design

• Objective Metrics

• Evaluation of Trial Data

• Platform Issues– lo end– hi end

• Immersive vs. Non-immersive Versions

The port-site simulator consists of a virtual model of an abdominal cavity with retracted liver and gallbladder, two virtual instruments, and a virtual scope providing variable angles and magnifications by an endoscope being moved into and out of the environment.

Overview of Simulator

Six Degree-of-Freedom trackers are attached to actual laparoscopic instruments which are inserted into trocars placed in a prosthetic abdomen shell.

The resulting virtual endoscopic view is displayed on a monitor as it would appear during an actual procedure.

The virtual abdominal model consists of a panoramic texture map made from composited frames taken from actual video footage of a laparoscopic cholecystectomy.

Prototype simulated task is cauterization and removal of the gallbladder during a laparoscopic cholecystectomy.

Trial Study Protocol

Requirements for a viable simulator:

- Must consistently demonstrate different performance for

different trocar locations and skill level of surgeon

Procedure: - Laparoscopic Cholecystectomy

Trial Subjects: - 10 medical students

- 10 senior residents and attendings

Grading metric: - Time to task at cauterization

- Accuracy of instrument movement

Simulator Runs: - Three runs each subject at varying port sites

- Repeat after two weeks

Current simulation is implemented in immersive and monitor based versions.

Both versions run on a Silicon Graphics 02.

Position Tracking is performed by Polhemus Fastrak.

Immersive version uses

•Sense8 World Toolkit

•Virtual Research VR-4 head mounted display.

Non-immersive version is implemented in Open Inventor

Hardware and Software Platforms