P1252428384EAFDg

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Development and testing of a compact endoscope
manipulator for minimally invasive surgery. Peter
Berkelman Ph.D.,Philippe Cinquin, Eric Boidard,
Joclyne Troccaz, Christian Letoublon and
Jean-Alexandre Long.

Presentation by, Rafiuddin Mohammed.
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Objective

• This report describes the design, development,
  and testing of a compact surgical assistant robot
  to control the orientation and insertion depth of
  a laparoscopic endoscope during minimally
  invasive abdominal surgery.
• In contrast to its counterparts, this is
  particularly compact and lightweight, is simple
  to setup and use, occupies no floor or operating
  table space, and does not limit access to the
  patient in any way.

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Introduction

• Minimally invasive surgical procedures, in
  contrast to conventional open surgery, are
  performed entirely using long, thin instruments
  through trocars up to 12mm in diameter inserted
  in miniature keyhole incisions.
• It provides advantage over open surgery by
  minimizing trauma and recovery time for the
  patient due to small size of the incisions.
• This procedure requires increased skill on the
  part of the surgeon, due to the length of the
  instruments and the constraint that the shaft of
  the instrument must pass through a pivot point at
  the incision.
• In addition, an endoscope with an attached camera
  must be inserted into the abdomen and held in a
  given pose to visualize the instrument tips
  internal tissues of the patient on a video screen
  during surgery.

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Contd.

• An assistant is typically required to hold the
  endoscope and video camera while the surgeon
  manipulates the laparoscopic instruments with
  both hands.
• To avoid requirement of an additional surgical
  staff, assistant can be replaced by a robotic
  endoscope manipulator. It is simple task for the
  robot to move an endoscope to a desired
  orientation and insertion depth inside the
  abdomen.
• Robots can handle the endoscope without tremor
  and fatigue during the procedures that may last
  several hours.

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Current endoscope manipulator robots

• Several robot systems have previously been
  developed for laporoscopic endoscope manipulation
  during surgery.
• These robots generally consist of a large, heavy
  base and a serial or parallel linkage arm to hold
  the endoscope.
• The AESOP and EndoAssist are two examples of
  currently available endoscope manipulator
  devices.
• Various clinical trials preformed with either
  AESOP or human assistant showed no significant
  difference in patient stay or post operative
  complications. The average time required was 235
  min with a human assistant and 213 min with
  AESOP.
• Procedures undertaken with manually held
  endoscopes required an average of 75 min, while
  procedures using EndoAssist required 66 min,
  resulting in a time saving of 9 min only.
• Since these robots are huge in structure, takes
  major space in an Operating Room (OR).

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Compact endoscope manipulator motivation

• Although current endoscope manipulators perform
  well, they resemble industrial robots and are
  generally large, heavy, complex and expensive.
  These occupies considerable amount of space next
  to the patient, which restricts the full access
  to the abdomen of the patient.
• Therefore, it would be advantageous to use a much
  more lightweight, simple and unobtrusive
  endoscope manipulator which would be easier to
  setup and use in ORs.
• The novel features of this endoscope manipulator
  are that it is sufficiently small and lightweight
  that can be directly placed on the abdomen of the
  patient, where it does not restrict access to the
  patient or motions of the surgeons arms and
  instruments the device is completely
  sterilizable and it does not require any setup
  or initialization procedure.

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Materials and methods

• The principal considerations in the design of the
  endoscope manipulator have been compact size, so
  as not to interfere with other handheld
  instruments during surgery
• It should be low weight to permit placement of
  the device on the abdomen of the patient.
• Earlier endoscope manipulator prototypes used
  cables to control orientation and to control
  insertion depth.
• Current prototype uses miniature motors
  integrated into robot mechanism.
• The current prototype is pictured in Figure1 and
  shown schematically in Figure2.

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Contd..

• The endoscope robot maybe attached to the patient
  and operating table by different means depending
  on the patient and procedures to be performed.
• For patients lying on their sides, and when
  maximum stability is necessary, the base ring
  maybe clamped to the side of the table by an
  articulated arm, as shown in Figure3.

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Motor Control

• Compact single-axis controllers provide
  proportional-integral (PI) error feedback control
  of the brushless motors with Hall-Effect sensor
  feedback.
• Motor controllers are programmed to operate in
  position-control mode to accurately hold a
  desired position and switch to velocity-control
  mode when motion commands are given.
• The controller parameters are fully configurable
  and can be written into motor controller EEPROMs.

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Motor control diagram
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Contd

• The motion commands to motor controllers are
  generated by a compact single board computer with
  multiple analog and digital inputs and outputs.
• Use of single-board computer eliminates the use
  of PC in OR.
• The PC and its serial port connection are only
  necessary for the use of the optical localizer
  or the voice-command recognition system.

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Command interfaces

• A voice-command recognition system has been
  implemented as a user command interface in
  combination with a single pedal which is used to
  control the movement of the endoscope camera.
• The following commands were used
• Move left/ Move right/ Move up/ Move down/Zoom
  in/Zoom out
• Step left/ Step right/ Step up/ Step down/ Step
  in/ Step out
• Switch on/ Switch off
• A miniature keypad is also provided to handle the
  endoscope, this can be operated by the index
  finger of the surgeon. This can be placed on any
  surgical instrument of the surgeon.

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Endoscope manipulator in use with instruments and
keypad
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Kinematics

• The kinematics of the current manipulator are
  simple and straightforward, as the actuator
  position variables determine the position of the
  endoscope camera expressed in spherical
  coordinates.
• The motions of the three motors directly
  correspond to vertical, horizontal and zoom
  motions of the endoscope camera image, so that no
  kinematic calculations are necessary during
  operation.

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Safety considerations

• To minimize any possibility of harm to the
  patient.
• The endoscope should be prevented from contacting
  internal tissues with forces high enough to cause
  tissue damage in case of failure of any device.
• The low size and weight of this manipulator is a
  safety benefit, as any collisions with internal
  organs dissipate less energy.
• The motion command interfaces of the endoscope
  manipulator are multiply redundant if any
  difficulty is encountered with the voice
  recognition system, the miniature keyboard on a
  surgical instrument maybe used.
• An electrocautery is commonly used in minimally
  invasive surgery, this can be eliminated by
  connecting all external metal parts of robot
  directly to electrical ground.

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Testing

• The endoscope manipulator has been used by
  surgeons to perform various minimally invasive
  surgical manipulator in an OR environment,
  obtained feedback from the surgeons regarding
  setup and operation, and various details of the
  manipulator.

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Conclusion

• Although testing with surgeons was limited, it
  provided better understanding of human interface
  and cleaning issues, and enabled minor
  modifications to be made in advance clinical
  trials.
• In summary, an endoscope manipulator with
  considerable advantages over current alternatives
  has been developed.

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Reference

• http//taylorandfrancis.metapress.com/index/L235V5
  7438765681.pdf
• Kobayashi, E, Masamune, K, Sakuma, I, Dohi, T and
  Hashimoto, D (1999) A new safe laparoscopic
  manipulator system with a five-bar linkage
  mechanism and optical zoom, Comput Aided Surg,
  4(4), pp. 18292.
• Taylor, R H, Funda, J, Eldridge, B, Gomory, S,
  Gruben, K, LaRose, D, Talamini, M, Kavoussi, L
  and Anderson, J A (1995) Telerobotic assistant
  for laparoscopic surgery, in R H Taylor, S
  Lavallée, G C Burdea and R Mösges (Eds). Computer
  Integrated Surgery Technology and Applications,
  pp. 58192

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