IMPLANTABLE ORTHOPEDIC SENSORS

Group 4Derek Sheesley

Sunil ShahMichael Iskhakov

Marina LouisAnthony Jones

Design Goal

Issues arise within prostheses without the doctors or wearers knowledge

Estimations ok but more exact measurements needed

Sensor that will [6]: Give real time information Alert the wearer when a problem arises

Constraints

Size 1 cm3

Wireless sensor [6] 2-5 millimeters across 500 microns thick

Biocompatibility (must be…) compatible with implant and body

micro-disc electrode arrays, poly hema hydrogels[3]

capable of withstanding forces in body

Constraints

Risk/Benefit Factor Biosensor must be made so that the risk of

failure, as well as risk of further damage, is reduced

Minimally Invasive Surgery should be kept minimal Use of ultra-thin flexible biosensors (<100

micrometers thick) to reduce size of incisions and risk of injury during surgery [5]

Affordable Must be relatively cheap

and be able to be mass-produced

Criteria

Strong, biocompatible material Stainless steel, titanium[2] Non-biocompatible materials coated with PEG

or PDMS [3]

Collection Good accuracy and precision Reduce noise with gyroscopic system [5] Telemetric data collection [6]

Criteria

Monitor state of implant and surrounding area Temperature, pH, force, pressure, etc. Early warning system

Power Supplies Kinetic and Thermoelectric energy harvesters

[1] Single inductor-capacitor component [4] Wireless (no electrical components)

WEAKNESSES

• FDA rationale: High risk to benefit ratio

• Highly Invasive• Number of parameters

measured • Signal Collectiona)Noise [5]b)Patient Confidentiality

STRENGTHS

Accurate Diagnostics

In the case of chronic infections of artificial joints associated

with bacterial biofilmWhich is less invasive?

TRAUMATIC IMPLANT REMOVAL SENSOR BACTERIAL ERADICATION

microelectromechanical system that could be embedded within the implanted joint to detect the presence of bacteria and to provide in situ treatment of the infection before a biofilm can form [4]

Dr. Sri, [THK], retrieved from : https://learn.dcollege.net/bbcswebdav/pid-2140270dtcontentrid7564780_1/courses/20764.201325/Total%20Knee%20Replacement_SB.pdf

Signal Collection

Is Patient confidentiality at risk when a form of wireless communication is used to read a

sensor?

Conclusion Incorporate a sensor into orthopedic prosthetics that will

monitor their condition as they are being used by patients. Example Prosthetics such as: Knee, Hip, Spine.

Sensors to record and transmit readings in concentration changes of specific substances present in surrounding blood and tissue.[8] Chemicals, Biological substances, Ions, etc.

Sensor can’t be more invasive than its partner prosthetic; must be compatible both with orthopedic implant and patient. Side effects of transmitting sensor can’t compromise the

benefits of implant

Transmission must be coherent, accurate and precise. Possible depending on coating of sensor, such as a

functionalized polymer coasting[8]

Ultimately, sensor will aid in gathering data to design a more efficient prosthetic.

Conclusion

[1] Andrea Cadei, et al,. 2013. Kinetic and thermal energy harvesters for implantable medical devices and biomedical autonomous sensors. Measurement Science and Technology, vol 25. Retrieved from: http://iopscience.iop.org/0957-0233/25/1/012003/pdf/0957-0233_25_1_012003.pdf

[2] Ehrlich G. et al,. 2006. Engineering Approaches for the Detection and Control of Orthopaedic Biofilm Infections. National Institute of Health (437): 59– 66. Retrieved from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC151327

[3] Gusphyl Justin, et al,. 2008. Biometric hydrogels for biosensor implant biocompatibility: electrochemical characterization using micro-disc electrode arrays(MDEAs). Biomed Microdevices, vol 11:103-115.

[4] Rensselaer Polytechnic Institute, 2012. Implantable, Wireless Sensors Share Secres of Healing Tissues. Retrieved from: http://search.proquest.com/docview/922474572

[5] Sirivisot S. et al,. 2006. Developing Biosensors for Monitoring Orthopedic Tissue Growth. Material Research Society, vol. 950. Retrieved from: http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8014 891

[6] Su-Jin K. et al,. 2012. Evaluation of the biompatibility of a coating material for an implantable bladder volume sensor. The Kaohsiung Journal of Medical Sciences, vol. 28, Issue 3: 123-129. Retrieved from: http://www.sciencedirect.com/science/article/pii/S1607551X11002397

SOURCES

[7] Umbrecht, et at,. 2010. Wireless implantable passive strain sensor: design, fabrication and characterization. Journal of Micromechanics and Microengineering vol. 20, 14. Retrieved from: http://iopscience.iop.org/0960-1317/20/8/085005/pdf/0960-1317_20_8_085005.pdf

[8] Guenther M., Gerlach G., et al. 2008. Hydrogel-based Sensor for a Rheochemical Characterization of Solutions. Sensors and Actuators B: Chemical. Transducers '07/Eurosensors XXI. Volume 132, Issue 2, 16 June 2008, Pages 471–476. Available: http://www.sciencedirect.com/science/article/pii/S0925400507009094

SOURCES

Questions?