Surgical Instruments for Robotic Open Microsurgery

Last updated: 5/14/17 1:36pm


The Galen robot is a cooperatively controlled robot which has been developed for the purpose of improving the speed and accuracy of microvascular anastomosis in otolaryngology. The usual microvascular instruments, when used with the Galen robot, can be difficult to maneuver and cannot optimally use the workspace afforded by the robot. The aim of our project is to develop alternative microvascular forceps and needle-holders that can be integrated with the Galen robot and enable the surgeons to perform the procedure with ease of manipulation, while respecting the workspace limits during normal operation.

  • Students: Radhika Rajaram, Olivia Puleo
  • Mentor(s): Yunus Sevimli, Dr.Russell Taylor, Dr.Christopher Razavi


Current Tool

Microvascular Anastomosis

The Galen robot

Background, Specific Aims, and Significance

Microvascular anastomosis is a surgical procedure which involves connecting small blood-vessels in order to restore circulation in transferred tissue/transplants or in reattached body parts that were severed. To assist the surgeons in performing the surgery faster and more precisely, the Galen robot (also known as the REMS robot or Steady-hand robot) was developed at Johns Hopkins University. The robot and surgeon both hold the surgical tool directly. The robot's algorithms cancels out the surgeon's hand tremor and ensures that the surgeon does not touch body sites where virtual fixtures have been placed. The current microvascular needle driver and forceps are held by the robot at the top and the surgeon holds the bottom the tool. This configuration has two problems:

  • The surgeon frequently runs into workspace limits
  • The tool is difficult to reorient because of the large lever arm

Our aim is to develop microvascular needle driver and or forceps to be integrated with the Galen robot that:

  • Can be held by the surgeon at the top and by the robot at the middle
  • Has good dexterity
  • Has a slim profile
  • Has a rotational degree of freedom about its own axis


  • Minimum: March 16
    1. 3D printed needle holder prototype - Done, but needs improvement
    2. Galen tool attachment with rotational degree of freedom - Done
  • Expected: April 9th
    1. Iterated design 3D printed in plastic - Done
    2. Preliminary testing with surgeons
    3. Stainless steel prototype - delayed due to outsourcing issues, expected in be received by May 24
  • Maximum: May 4th
    1. Microvascular holder instrument - Done
    2. Design for manufacturing ability - Done
    3. Sterilizable - delayed due to outsourcing issues, expected in be resolved by May 24

Technical Approach

  • Take apart existing forceps and cannibalize useful parts.
  • Design different gripper/actuators for the forceps.
  • Design tool-holder accessory for rotational DOF
  • Prototype feasible designs
  • Test with Galen and evaluate
  • Iterate over design and fabrication methods

There are many varieties of forcipes with different mechanisms of actuation, grips and jaws adapted to every surgical application such as grasping, holding, clamping, cutting, dissecting, dilating, suctioning etc.

Based on mechanism of actuation we have three main categories:

  • 1) Scissoring type
  • 2) Tweezer type
  • 3) Sliding rod type

Based on grip design we have three categories:

  • 1) Loop grip
  • 2) Tweezer grip
  • 3) Pliers grip

The sliding rod type is typically used where there is a very narrow entrance to the surgical site. Since, it easily allows for the addition of a rotational attachment we prefer this mechanism type.

As for the grip design we have to choose the tweezer grip in consideration of the ergonomics of the operation.

We will be cannibalizing the lower part of existing microsurgery tools (mainly the jaws)

Here are some of the designs that we have come up with:

Design 1: Round grip

The first features an inherently-deformable grip that is symmetric about the axis of the tool. There are twelve bending strips, preferably made of thin sheet metal steel which when pressed, push the sliding ring upwards which in turn pushes up the sliding rod that actuates the jaws below. When released, the tool returns to its original position by virtue of the elasticity of steel. As we are currently prototyping with 3D printed plastic, we have put this design on hold. Another issue is the large number of parts that makes assembly more tedious than it needs to be.

Design 1: Round grip - upate

In this modification of design 1, we have fused the top half of the bending strips with the sliding ring and the bottom half with the cylinder body. The two parts are connected by a pin joint which allows for just enough deformation when printing in ABS plastic.

In a two material printer, the pin joint can be replaced by a second material of lower stiffness. The previous design had around 16 parts, while this design has only 4.

Design 2: Tweezer grip

We chose to work on this design as it has fewer components and complexity compared to the previous one. The tweezer handle has a semi-cylindrical shape for rotatability. The tweezer is one part, preferably stainless steel with the arms being thinner (like sheet metal), so as to allow for elastic deformation.

Design 2: Tweezer grip update

We are currently prototyping with plastic, as a result the tweezer from the above design becomes three components- two arms and a cap. The arms are held at the cap by a pin joint. A spring along the axis of the cylinder provides the elastic return.

This is the most promising design so far, as we are not depending on material elasticity.

Design 2: Tweezer grip update 2

We have switched the handle attachment point from the ring to the top and made the angle between teh connecting link and the rod more obtuse. This allows for a larger ring.


  • Access to Galen - Resolved
  • Machine shop access - Resolved
  • Funds for training, machining, and prototyping - Resolved
  • Access to residents and trained surgeons - We are talking with our mentors about who may be interested. If this isn't resolved, we can still have our instrument finished, it just will not have as much feedback.

Milestones and Status

  1. Milestone name: 3D printed CAD model
    • Planned Date: March 16, 2017
    • Expected Date: March 16, 2017
    • Status: COMPLETED
  2. Milestone name: Improved Design
    • Planned Date: April 9, 2017
    • Expected Date: April 9, 2017
    • Status: COMPLETED
  3. Milestone name: Stainless Steel Prototype
    • Planned Date: April 21st, 2017
    • Expected Date: April 21st, 2017
    • Status: Delayed due to outsourcing issues, expected to be received by May 24
  4. Milestone name: Evaluation of modified design
    • Planned Date: May 4, 2017
    • Expected Date: May 4, 2017
    • Status: Delayed due to outsourcing issues, expected to be received by May 24

Reports and presentations

Project Bibliography

  • Daniel, R. K., & Williams, H. B. (1973). THE FREE TRANSFER OF SKIN FLAPS BY MICROVASCULAR ANASTOMOSES: An Experimental Study and a Reappraisal. Plastic and Reconstructive Surgery, 52(1), 16-31.
  • Gudeloglu, A., Brahmbhatt, J. V., & Parekattil, S. J. (2014). Robotic-Assisted Microsurgery for an Elective Microsurgical Practice. Seminars in Plastic Surgery, 28(1), 11–19. Retrieved from
  • Katz, R. D., Rosson, G. D., Taylor, J. A., & Singh, N. K. (2005). Robotics in microsurgery: use of a surgical robot to perform a free flap in a pig. Microsurgery, 25(7), 566-569
  • MacDonald JD.(2005) Learning to perform microvascular anastomosis. Skull Base - an Interdisciplinary Approach. 2005;15:229.
  • Malis, L. I. (1985). Instrumentation for microvascular neurosurgery. In Cerebrovascular Surgery (pp. 245-260). Springer New York.
  • Taylor, R., Jensen, P., Whitcomb, L., Barnes, A., Kumar, R., Stoianovici, D., … & Kavoussi, L. (1999). A steady-hand robotic system for microsurgical augmentation. The International Journal of Robotics Research, 18(12), 1201-1

Reading list

Patkin, M. (1977), Ergonomics Applied to the Practice of Microsurgery. Australian and New Zealand Journal of Surgery, 47: 320–329.

Lee, G., Lee, T., Dexter, D., Klein, R., & Park, A. (2007). Methodological Infrastructure in Surgical Ergonomics: A Review of Tasks, Models, and Measurement Systems.Surgical Innovation,14(3), 153-167.

Hignett, S., & Mcatamney, L. (2000). Rapid Entire Body Assess ment (REBA).Applied Ergonomics,31(2), 201-205.

Other Resources and Project Files

Here give list of other project files (e.g., source code) associated with the project. If these are online give a link to an appropriate external repository or to uploaded media files under this name space.

courses/446/2017/446-2017-01/project.txt · Last modified: 2019/08/07 12:01 (external edit)