Development of Depth Gage Instrument

Brian CostJustin Johnson

Tyler KibbeeFebruary 19, 2008

Project Description Design, build and test an improved depth

gage instrument for a variety of orthopedic surgeries

Achieve bi-cortical fixation using a compression stopper

Ergonomic Grip Ease of use for surgeons

Accuracy Proper depth and correct size screw used

Existing Design Inadequate measurements

Unable to engage far cortex of bone Poor repeatability

Discuss weaknesses in MAUDE results

Current Status Obtained 2 saw bone models

Hand and Foot models

Additional implants on order Drill Bits, drivers Plates, screws

Revised switch to compress tip Set up to meet with Doctors at VUMC

Dr. Dan Spengler Dr. Kurt Spindler Dr. Thomas Limbird

Feedback Derek Lewis, advisor

Surgeons are used to ergonomics of old design—minimal changes

Currently critiquing design with president of OrthoHelix

Surgeons Design needs to be for one handed operation Needs to slide smoothly Switch needs to be relatively easy to flip

Current Depth Gage Design

Switch Demonstration

Tip Demonstration

Before Compression

(switch disengaged)

After Compression

(switch engaged)

Experimental Testing Material testing

Stainless steel Autoclave

Medical-grade Silicon Autoclave, heat resistance

Failure testing Pull-out strength

Amount of force needed to pull silicon through hole Silicon-strength testing

Bone pressing against silicon

Sawbone Models

FDA Classification Class I – Surgical devices

Sec. 888.4300 Depth gauge for clinical use. (a) Identification. A depth gauge for clinical use is a

measuring device intended for various medical purposes, such as to determine the proper length of screws for fastening the ends of a fractured bone.

(b) Classification. Class I (general controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter, subject to the limitations in 888.9.[52 FR 33702, Sept. 4, 1987, as amended at 66 FR 38815, July 25, 2001]

Project Timeline SolidWorks 7.0 3D modeling

Revise 3D models with advisor Create additional Model Simulation

Shadow Surgeons at VUMC Product design input

SLA plastic prototype Quick, cheap prototype for visual inspection 1st SLA deadline: On order (pending design approval)

Test SLA prototype Use saw bone models to conduct testing

Prototype contract Prepare for FDA approval Might not be before 4/22/08

Summary of Maude Database Results Malfunction

Improper depth measurement Depth gauge does not read accurately. When used, the depth gauge reads

long. Depth gauge for cortex screws was sticking and provided an incorrect

measurement Translation mechanism failure

The depth gauge is not sliding smoothly Depth gauge for cortex screws was sticking and provided an incorrect

measurement Tip Failure

A modified depth gauge reportedly broke during surgery. A ball-tip that was 3mm in diameter had fallen off and was left in the patient.

Injury - None Serious Injury/Death - None

Complaints/Incidences of Malfunction

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4

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

Year of Incident

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OSTEOMED HOWMEDICA SMITH & NEPHEW, INC

SMITH & NEPHEW RICHARDS ZIMMER, INC STRYKER SPINE BORDEAUX

SYNTHES, USA

Questions?