Medical optical localizer based on Apple iPhone smartphone

Medical navigation providing intraoperative localization of medical instruments plays a crucial role in computer assisted surgery (CAS). Several different multiple- camera standalone optical localizers are available on the market nowadays. Our aim was to develop, easy-to-use, low-cost and portable medical localizer based on iPhone 6S camera. We decided to develop a specialized smartphone app which is able to detect two rigid bodies (RB) on the camera screen and estimate their position both in devices and global coordinate system using sensor fusion with smartphones accelerometer and gyroscope. In the procedure one RB serve as reference and the other is attached to the tool. The prototype was preliminary calibrated using 2D and 3D VDI/VDE 2634 standard. Validation procedure involved measurements of the position and distance of two RBs placed 500 mm from each other in a distance of 1 meter to the smartphones camera. The measurements were taken from three different angles: -30°, 0°, 30° regarding RBs plane. The standard deviation of the measured distance was 0.62 mm with average measured distance of 498.0 mm. The other tests were made in a test-setup where the virtual offset of ultrasound probe was added to one of the RBs so the distance between probe and reference was 195 mm. The tests showed that the position of ultrasound probe is estimated with standard deviation of 0.70 mm and the average measured distance is 195.18 mm. Due to the promising results of those evaluations, we plan to perform more specific tests in clinical setup in near future.

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Post Operative Analysis of a Novel Application of Surgical Navigation

10.29007/qmm6 ◽

2020 ◽

Author(s):

Benjamin Roberts ◽

Willy Theodore

Keyword(s):

Surgical Navigation ◽

Sagittal Alignment ◽

Low Cost ◽

Femoral Condyle ◽

Computer Assisted Surgery ◽

Patient Specific ◽

Computer Assisted ◽

Tibial Resection ◽

Patient Specific Instrumentation ◽

The Mean

A cohort of 84 patients underwent Total Knee Replacement surgery using Patient Specific Instrumentation fitted with an optical tracker that was monitored by a Computer Assisted Surgery system. The CAS system was low cost with small footprint in the operating theatre. The hip centre was collected and four other landmarks were recorded as rotational measures. The CAS system then reported the deviation in PSI placement against the targeted PSI placement, the surgeon then made a judgement whether to replace the guide. Post-operative analysis was done to determine the achieved alignment of the component and compared to the targeted alignment. From 45 results available for analysis the study found that the mean of rotational measures over the femur and tibia were found to be within ±30 of the targeted alignment, except for femur sagittal alignment. When a single outlier was removed from the femur sagittal alignment measures, the mean fell below ±30 of the targeted alignment. Distal femoral condyle resection measures fell below a mean of 1mm and posterior femoral condyle measures fell below a mean of 2mm. Lateral proximal tibial resection fell below a mean of 2.5mm as did medial proximal tibial resection when two outliers were removed. This shows that a CAS system incorporating the low cost, quicker time, and smaller footprint benefits of PSI with the accuracy of traditional navigation may be a feasible device.

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Virtual movements-based calibration method of ultrasound probe for computer assisted surgery

2009 IEEE International Symposium on Biomedical Imaging: From Nano to Macro ◽

10.1109/isbi.2009.5193278 ◽

2009 ◽

Cited By ~ 4

Author(s):

J. Chaoui ◽

G. Dardenne ◽

C. Hamitouche ◽

E. Stindel ◽

C. Roux

Keyword(s):

Computer Assisted Surgery ◽

Calibration Method ◽

Computer Assisted ◽

Ultrasound Probe

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A non-invasive patient registration and reference system for interactive intraoperative localization in intranasal sinus surgery

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1243/0954411971534458 ◽

1997 ◽

Vol 211 (4) ◽

pp. 327-334 ◽

Cited By ~ 10

Author(s):

R Hauser ◽

B Westermann ◽

R Probst

Keyword(s):

Paranasal Sinuses ◽

Image Data ◽

Computer Assisted Surgery ◽

Surgical Instruments ◽

High Rate ◽

Sinus Surgery ◽

Computer Assisted ◽

Non Invasive ◽

Custom Made ◽

Intraoperative Localization

A basic problem common to all systems for computer assisted surgery (CAS) is patient referencing, or the transfer of preoperative image data to the intraoperative pathology. The authors describe a highly precise CAS system with non-invasive referencing that can be used in ear, nose and throat (ENT) surgery of the paranasal sinuses. It is based on optical digitizing with several custom-made self-localizing surgical instruments. The accuracy of the system was tested in an experimental model using a plastic head. Measurements of repositioning the reference bow had a mean error of 0.81 mm + 0.31 mm. The system was evaluated clinically with 11 patients who received surgery for different pathologies of the paranasal sinuses. These trials met with a high rate of success and specific results are reported.

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Analyzing Language in Suicide Notes and Legacy Tokens

Crisis ◽

10.1027/0227-5910/a000363 ◽

2016 ◽

Vol 37 (2) ◽

pp. 140-147 ◽

Cited By ~ 6

Author(s):

Michael J. Egnoto ◽

Darrin J. Griffin

Keyword(s):

Text Analysis ◽

Low Cost ◽

Computer Software ◽

Student Writing ◽

Computer Assisted ◽

Automated Identification ◽

Completed Suicide ◽

Suicide Notes ◽

Self Harm ◽

Harm To Others

Abstract. Background: Identifying precursors that will aid in the discovery of individuals who may harm themselves or others has long been a focus of scholarly research. Aim: This work set out to determine if it is possible to use the legacy tokens of active shooters and notes left from individuals who completed suicide to uncover signals that foreshadow their behavior. Method: A total of 25 suicide notes and 21 legacy tokens were compared with a sample of over 20,000 student writings for a preliminary computer-assisted text analysis to determine what differences can be coded with existing computer software to better identify students who may commit self-harm or harm to others. Results: The results support that text analysis techniques with the Linguistic Inquiry and Word Count (LIWC) tool are effective for identifying suicidal or homicidal writings as distinct from each other and from a variety of student writings in an automated fashion. Conclusion: Findings indicate support for automated identification of writings that were associated with harm to self, harm to others, and various other student writing products. This work begins to uncover the viability or larger scale, low cost methods of automatic detection for individuals suffering from harmful ideation.

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