Otologic Surgical Drills Julianna Ianni Meher Juttukonda David Morris Advisor Dr Jadrien Young MD What is Otologic Surgery Surgery of the ear Mastoidectomy Mastoid airfilled spaces behind the ear ID: 549003
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Slide1
Ultrasound Imaging Capability for Otologic Surgical Drills
Julianna IanniMeher JuttukondaDavid MorrisAdvisor: Dr. Jadrien Young, M.D.Slide2
What is Otologic Surgery?
Surgery of the earMastoidectomyMastoidair-filled spaces behind the earUsesto remove cells from the mastoidto treat anti-biotic resistant infections in the regionto insert a cochlear implant30,000 to 60,000 performed annually in the U.S. [1]Slide3
Anatomy of the EarSlide4
Mastoidectomy ClipSlide5
ObjectivesTo find and attach an ultrasound transducer to an
otologic surgical drill. To calculate the thickness of the mastoid bone using USTo shut off the drill when the mastoid bone has been drilled or provide the surgeon with enough information to stop at the correct distance. Slide6
Why Ultrasound?
CategoryCT - MethodUltrasoundSafetyIonizing RadiationNo Ionizing Radiation
Real-time Data
Time
Drilling
Platform
Not necessary
Invasiveness
Invasive
Non-invasiveSlide7
Past Work
Studied ultrasound equipment in order to determine the most effective way to produce accurate imagesResearched the best transducer frequency for imaging that region of the skullDeveloped the websiteObserved use of otologic drills & identify design constraintsIdentified potential design obstaclesGenerated design ideas concerning mechanism of attachment
Restructured design goals focusing more on finding an ultrasound transducer compatible with an
otologic
drill.
Performed some proof of concept tests for ultrasound depth measurements through bone. Slide8
Solidworks Prototype
Side ViewTop ViewBottom ViewSlide9
The PrototypeThe ultrasound transducer is placed so that it allows for the surgeon to quickly move the transducer into place to perform quick ultrasound scans.
When not in use the transducer can be moved back out of the way and will allow the surgeon to quickly return to work. This set up allows for the surgeon to work quickly and prevents them from wasting a lot of time during surgery while also adding a safer means of cutting through the bones. Slide10
Model of MastoidBone -> Acrylic
Speed of Sound = 2750 m/s [4]Soft Tissue -> GelSpeed of Sound ~ 1540 m/sSlide11
Analysis of SimulationSlide12
Results of simulation(gradient plots matched well w/ built-in edge detection)
Worked really well with 1 layer of acrylic:Actual thickness= 2.03mmMeasured thickness= 2.23mm w/o tissue & 2.35mm w/tissueFor 4MHz: 2.13mm & 2.23mm respectivelyWant accuracy w/in 1mm Slide13
Multiple layers of acrylic?Harder to read
Multiple peaks (including ones at the correct thickness)Not as distinct from noiseAble to discern correct peaks knowing thickness, but can’t back them out just from dataMost likely due to small air-pockets between layers of acrylic caused more echoes & attenuation @ ea. intersectionSlide14
Multiple layers
Depth(cm)y-gradient amplitude
Example with 2 layers of acrylic
(total thickness= 4.06mm)
w/tissue layer
8.89MHzSlide15
Statistics
No.Layers
f (MHz)
Tissue
Thickness(cm)
Thickness(cm)
error(mm)
error(mm)
% Error
% Error
Layer 1
Layer 2
Layer 1
Layer 2
Layer 1
Layer 2
1
1
8.89
N
0.2275
0.243
11.96
2
1
8.89
Y
0.2398
0.366
18.01
3
1
4
N
0.2164
0.132
6.50
4
1
4
Y
0.2272
0.24
11.81
5
2
8.89
N
0.2023
0.4298
-0.009
0.234
-0.44
5.76
6
2
8.89
Y
0.2398
0.4543
0.366
0.479
18.01
11.79
7
2
4
N
0.2023
0.4298
-0.009
0.234
-0.44
5.76
8
2
4
Y
0.2394
0.4283
0.362
0.219
17.81
5.39
Actual
1st Layer
0.2032
cm
Thickness
2nd Layer
0.4064
cm
Tissue
0.2
cmSlide16
Future Work
Getting transducers in & testing (high frequency and low frequency)building prototype & attachment for drillcalibrating/signal processing and analysisSlide17
References1. French, LC et al. “An estimate of the number of
mastoidectomy procedures performed annually in the United States”. Ear Nose Throat J. 2008 May; 87(5): 267-70.2. Ear Anatomy: http://www.umm.edu/imagepages/1092.htm3. Clement, GT et. Al. “Correlation of Ultrasound Phase with Physical Skull Properties”. Ultrasound in Medicine & Biology. 2002 May; 28(5): 617-624.4. http://www.signal-processing.com/tech/us_data_plastic.htm