Simulation Study of Sensitivity Performance of MEMS Capacitive Bending Strain Sensor for Spinal Fusion Monitoring

This study evaluates the sensitivity of microelectromechanical system (MEMS) capacitive bending strain sensor with a double layer cantilever designed to meet the requirements of spinal fusion monitoring. The cantilever structure of the sensor consists of two parallel substrate plates which constitute the electrodes, attached to an anchor made of silicon dioxide. The sensor was able to monitor bending strain value ranging from 0 to 1000 με. In order to evaluate the sensitivity of the sensor, parametric study was carried out by varying electrode gap, anchor length, and dielectric coverage between the electrodes. The nominal capacitive strain sensor for various applications has sensitivity ranging from 255 aF/μεto 0.0225 pF/με. An increase in the sensitivity was observed on reducing the electrode gap and the anchor length and increasing the dielectric coverage, resulting in a highest sensitivity value of 0.2513 pF/με. It was also observed that dielectric constant has a significant effect on the sensitivity behavior of the sensor.

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Development of a Strain Transferring Sensor Housing for a Lumbar Spinal Fusion Detection System

Journal of Medical Devices ◽

10.1115/1.2735971 ◽

2006 ◽

Vol 1 (2) ◽

pp. 159-164 ◽

Cited By ~ 2

Author(s):

J. W. Aebersold ◽

W. P. Hnat ◽

M. J. Voor ◽

R. M. Puno ◽

D. J. Jackson ◽

...

Keyword(s):

Finite Element ◽

Spinal Fusion ◽

Detection System ◽

Spinal Instrumentation ◽

Strain Sensor ◽

Internal Surface ◽

Disc Disease ◽

Bending Strain ◽

Exploratory Surgery

Lumbar arthrodesis or spinal fusion is usually performed to relieve back pain, and regain functionality from degenerative disc disease, trauma, etc. Fusion is determined from radiographic images (X-ray) or computed tomography scans, yet these inspection procedures are subjective methods of review. As a result, exploratory surgery is performed if the presence of fusion cannot be confirmed. Therefore, a need exists to provide objective data to determine the presence of fusion that could avoid the cost, pain, and risk of exploratory surgery. One method to achieve this objective is to observe bending strain from spinal rods implanted during surgery. A system has been developed that will attach to the spinal instrumentation rods, transmit strain information wirelessly, and without the use of batteries. Major components of the system include a strain transferring sensor housing, a microelectromechanical (MEMS)-based strain sensor, telemetry circuitry, and antennae. Only discussed herein are the design, testing, and results of the housing without a cover and its ability to transfer strain from the rod to an internal surface where a foil strain gage is attached to characterize strain transfer efficiency. Strain gauges rather than the MEMS sensor were employed for housing characterization due cost and limited availability. Design constraints for the housing are long-term implantation, small size, greater than 95% transfer of bending strain from the spinal rods to the internal strain sensor, and ease of installation. ABAQUS finite element modeling software was employed to develop a working model that was fabricated using polyetheretherkeytone. The housing underwent cycle testing in a material testing system to simulate long-term implantation along with static testing to determine if creep was present. Both series of tests showed that the housing’s response did not degrade over a period of time and there was no indication of creep. The experimental results also validated the results of the ABAQUS finite element model.

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Development of capacitive pure bending strain sensor for wireless spinal fusion monitoring

Sensors and Actuators A Physical ◽

10.1016/j.sna.2007.04.069 ◽

2007 ◽

Vol 138 (2) ◽

pp. 276-287 ◽

Cited By ~ 14

Author(s):

Ji-Tzuoh Lin ◽

Kevin W. Walsh ◽

Douglas Jackson ◽

Julia Aebersold ◽

Mark Crain ◽

...

Keyword(s):

Spinal Fusion ◽

Strain Sensor ◽

Pure Bending ◽

Bending Strain

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Design and simulation of a MEMS capacitive bending strain sensor using dielectric materials for spinal fusion monitoring

2011 IEEE Regional Symposium on Micro and Nano Electronics ◽

10.1109/rsm.2011.6088354 ◽

2011 ◽

Cited By ~ 1

Author(s):

Muhammad Irsyad Abdul Mokti ◽

Inzarulfaisham Abd. Rahim ◽

Asrulnizam Abd Manaf ◽

Othman Bin Sidek ◽

Muhamad Azman Bin Miskam

Keyword(s):

Spinal Fusion ◽

Strain Sensor ◽

Dielectric Materials ◽

Bending Strain

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A Highly Stable and Durable Capacitive Strain Sensor Based on Dynamically Super‐Tough Hydro/Organo‐Gels

Advanced Functional Materials ◽

10.1002/adfm.202010830 ◽

2021 ◽

pp. 2010830

Author(s):

Funian Mo ◽

Yan Huang ◽

Qing Li ◽

Zifeng Wang ◽

Ruijuan Jiang ◽

...

Keyword(s):

Strain Sensor ◽

Capacitive Strain

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Package-induced temperature dependence of MEMS capacitive strain sensor and system design considerations

2012 IEEE 25th International Conference on Micro Electro Mechanical Systems (MEMS) ◽

10.1109/memsys.2012.6170242 ◽

2012 ◽

Author(s):

Darrin J. Young ◽

Michael A. Suster ◽

Wen H. Ko

Keyword(s):

Temperature Dependence ◽

System Design ◽

Strain Sensor ◽

Design Considerations ◽

Capacitive Strain

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Active Temperature compensation for MEMS capacitive sensor

10.36227/techrxiv.14379917.v2 ◽

2021 ◽

Author(s):

Cuong Do ◽

Ashwin A. Seshia

Keyword(s):

Energy Harvesting ◽

Low Power ◽

Temperature Variation ◽

Temperature Compensation ◽

Strain Sensor ◽

Capacitive Sensor ◽

Structure Design ◽

Mems Sensors ◽

Capacitive Strain ◽

Active Temperature

Temperature variation is one of the most crucial factors that need to be cancelled in MEMS sensors. Many traditional methodologies require an additional circuit to compensate for temperature. This work describes a new active temperature compensation method for MEMS capacitive strain sensor without any additional circuit. The proposed method is based on a complement 2-D capacitive structure design. It consumes zero-power, which is essential toward the realization of a low-power temperature-compensated sensor in battery-powered or energy-harvesting applications<br>

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A Sawtooth MEMS Capacitive Strain Sensor for Passive Telemetry in Bearings

IEEE Sensors Journal ◽

10.1109/jsen.2021.3107441 ◽

2021 ◽

pp. 1-1

Author(s):

Chi Zhang ◽

Shang-Yang Zhang ◽

Li-Feng Wang

Keyword(s):

Strain Sensor ◽

Capacitive Strain

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Polydiacetylene hydrogel self-healing capacitive strain sensor

Journal of Materials Chemistry C ◽

10.1039/d0tc00576b ◽

2020 ◽

Vol 8 (18) ◽

pp. 6034-6041 ◽

Cited By ~ 5

Author(s):

V. Kesava Rao ◽

Nitzan Shauloff ◽

XiaoMeng Sui ◽

H. Daniel Wagner ◽

Raz Jelinek

Keyword(s):

Strain Sensor ◽

Mechanical Deformation ◽

Human Motion ◽

Self Healing ◽

Highly Sensitive ◽

Capacitive Strain

Highly sensitive and stretchable PDA–PAA–Cr3+ hydrogel capacitive strain sensor is fabricated and used to monitor mechanical deformation and human motion.

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