Designing a Custom 3D Printed Ankle Cage Implant
Designing a Custom 3D Printed Ankle Cage Implant
Designing a Custom 3D Printed Ankle Cage Implant
Cystoscope Redesign
Background and Motivation:
Cystoscopies are used to diagnose, monitor and treat conditions affecting the bladder and urethra. There are currently two types of cystoscopies: flexible and rigid. Flexible cystoscopies are often used for diagnostic or observational purposes whereas rigid cystoscopes are used when the surgeon needs to insert instruments into the working channel for taking biopsies or carrying out procedures (tumor ablation, bladder stone removal, repairing bleeding vessels, treating bleeding etc). During rigid cystoscopies, the patient is generally sedated or given general anesthesia. However, as the medical field increasingly shifts towards minimally invasive procedures and reducing the use of anesthesia, patient comfort and perception of the procedure becomes incredibly important.
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Currently, rigid cystoscopes look cold, sterile, and extremely intimidating. No patient would be happy to see a clinician approach them with a rigid cystoscope. For this reason, the field of urology could greatly benefit from a rigid cystoscope redesign.
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Design Criteria:
The redesigned cystoscope must accommodate a "Photon Engine" containing all relevant visualization components, a 20cm long circular sheath, an electrical 3-pole connection, luer-lock connections for water inflow and outflow, a water pipe that connects the luer-locks to the sheath, and valve controls to control water flow. The two halve of the cystoscope must be assembled and fixed together in some way to allow for comfort and ease of use for the urologist.
Mood Board
Early Sketches
Some key words that were important to the initial design of the cystoscope were: Ergonomic, Clean, Safe, Familiar, and Comfortable
Final Sketch Designs
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These initial rough sketches explore the different grip styles that the physician could use to hold the cystoscope as well as several different handle designs
Final Model
LBM & BOM:
The final cystoscope model comes in two halves for easy injection molding. The two halves are properly shelled and drafted, and can be joined together with three screws. The ergonomic shape draws inspiration from the Wii remote and follows the natural curvature of the hand. Additionally, it is both left and right hand friendly and allows the urologist to operate the cystoscope with only one hand.
FEA Analysis
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An FEA analysis was conducted to determine the stress hotspots and overall safety factor for one loading condition on the cystoscope. In this case, 40N of downwards force was placed on the end of the sheath to simulate a bending moment that could be created when the urologist pushes the cystoscope handle up or downwards to navigate the sheath through the patient's urethra. The nozzle of the cystoscope was isolated to simplify calculations.
A minimum safety factor of 1.8 shows that this cystoscope nozzle is able to withstand a 40N load at the end of the sheath with a sufficient level of safety.