1. Redesign of Otologic Surgical Instruments
Brian Chow and Joy Nystrom
Mechanical Engineer: Ryan Josefovsky
Advisor: Russ Johnson, PhD-Smith and Nephew
BME 273
March 19, 2001

2. Ear Surgery Otitis Media (Middle Ear Infection)
Upwards of 800,000 surgeries/year
Around 11 million cases total
Closure of Tympanic Membrane Perforations

3. Ear Surgery Otosclerosis Removal of Tumors Cochlear Implants
10-18% of women aged 30-50
7-9% of men aged 30-50
Removal of Tumors
Cochlear Implants
14,000 Americans
The Boys Town Research Registry for Hereditary Hearing Loss

4. Potential Market 100,000 Ear, Nose, and Throat (ENT) Physicians
1000 Neurosurgeons

5. Problem
Otologic surgery requires delicate maneuvering in limited space
ossicles <3 mm
cavities ~1 cm
Current method requires large hand movement

6. A large hand movement (1 cm) causes a small tip movement (4 mm).
1 inch
1 inch
A large hand movement (1 cm) causes a small tip movement (4 mm).
Movement requires compensation by user.

7. Proposal
Create a system that will allow identical movement of the instrument in an ear of a patient with a fingertip-controlled drive mechanism
Brackmann, Otologic Surgery

8. The Task
Redesign the back end and drive mechanism for fingertip control
Maintain tip movement identical to current instruments
Back End/
Drive Mechanism
Tip

9. The Task There are different kinds of tips grasping cutting spreading
Courtesy of Smith and Nephew

10. Reasons Fingertip control allows for: Steadier hand control
Higher precision with finger movement
Better access to inner ear

11. Advantages Reduced motion of surgeon’s arm results in:
A lowered margin of error
A potential for reducing amount of training required for proficiency
A potential for better ergonomics
Similar cost

12. Research and Brainstorming

13. Patent Search New problem, few previous patents, little information
Similar to laparoscopic surgery

14. Possible solutions Screw mechanism Pulleys (#5,976,122) Gears Slide
Concentric Wheels
Levers

15. Concentric Wheel Design
Concentric wheels designed to scale motion.
Solid metal shafts

16. Concentric Wheel Flaws
Requires larger handle (about the size of a fountain pen)
Finger moves in a sliding motion

17. Current Design

18. Advantages
More compact
Push-button mechanism
Fewer, more stable parts

19. Future Work Obtain Specifications Complete design on CAD program
Consult with manufacturing
Evaluate safety of design

20. Questions?