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Maureen Loughran Gregory Ragosta Christina Felarca Adham Sohby. Steel Bar Midterm Presentation mae 435. What is Pectus Excavatum?. Deformity of the chest and rib cage Most common in children but also occurs in adults. 16-Year Old Boy With Severe Pectus Excavatum. The Nuss Procedure.
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Maureen Loughran Gregory Ragosta Christina Felarca Adham Sohby Steel Bar Midterm Presentationmae 435
What is Pectus Excavatum? • Deformity of the chest and rib cage • Most common in children but also occurs in adults 16-Year Old Boy With Severe PectusExcavatum
The Nuss Procedure • First developed by Dr. Donald Nuss, a pediatric surgeon at CHKD • Stainless steel/titanium bar is bent according to the shape of the patient’s chest • Minimum blood loss • Shorter operation and recovery time Nuss Procedure
The Nuss Procedure cont’d • The bar stays inside the patient for an average of 2-3 years • 4% of pectus excavatum cases undergo the Nuss Procedure more than once, because the bar is removed too soon Before and After
Objective • To develop a steel bar prototype that will allow doctors to know the appropriate time to remove the bar from the patient without the risk of the chest wall regressing back to its original state, while conducting this information outside of the body wirelessly to provide the least additional discomfort for the patient. • Real Proof of Concept prototype and Ideal Model
Radio Frequency Identification (RFID) • Miniature device that can wirelessly transfer data from a RFID reader • Takes in a radio signal and transmits back out the stored information on the tag • Many different uses, such as electronic payment systems, goods tracking, and systems monitoring. • Semi-passive RFID • vs. Active or Passive RFID
WISP • Wireless Identification and Sensing Platform • Developed by Intel • Built in Gyro., Accel., and Temp. • Wireless, battery-free • Powered solely by RF absorbed by antenna
WISP cont’d Wisp Functional Diagram
Intel’s Strain Gauge Solution • Strain gauge PCB has to be built to interface WISP with strain • Wheatstone Bridge • Amplifier SGPBC
Our Solution • Our solution: • Place 1 strain gauge on the surface of the bar • Using Intel’s strain gauge solution, we can connect the strain gauges to the WISP via a Wheatstone bridge and amplifier • The WISP will interface with the reader (outside of the patient) and report the data using WISP’s reader software • Ideal model will have 2 strain gauges with all the components built into the bar itself.
Steel Bar • Titanium Bar • Bent at factory in ideal shape. • Stainless Steel Bar • 9 in • Young‘s Modulus: 192 Gpa • Poisson’s Ratio: 0.265
Building the WISP Impinj Speedway 1000 RFID Reader
Building the WISP cont’d Antenna (900-925 MHz)
Building the WISP cont’d • Strain Gauges • SGD-13/1000-LY11 • 13 mm grid, 1000 ohms Strain Gauge
Real Prototype Model AutoCAD Model
Ideal Prototype Model (Unfinished) AutoCAD Model
Theoretical Design • Redesign of the WISP, Amplifier, and Wheatstone bridge for ideal model. • Volume calculations with a design factor of 1.2 • Black box (Not redesigning the electrical components). • Used to fit the components within the bar itself, including the Arcs. • Unbendable components such as the MCU of the WISP will be in straight portions.
What’s next? • Goals • To test each set of equipment in a piecewise manner to ensure that everything is working • To setup equipment • Challenges • Building the circuit board • Noise
References • 16-Year Old Boy With Severe PectusExcavatum. Medscape: Medscape. • Nuss Procedure. http://surgvideo.surg.sunysb.edu/Volumes/ACSCD+July+2010/ACSCD/figures/ch0409-f6.htm • Before and After. http://www.gundluth.org/pediatrics/surgery/sunken-chest • Wisp Functional Diagram. 2011. Elsevier. Feb. 19, 2013. • SGPBC. 2011. Elsevier. Feb. 20, 2013. • Strain Gauge. http://www.omega.com/pptst/SGD_LINEAR1-AXIS.html