Cystoscope Redesign

Starting the Design Process

 

  • Cystoscopy is used to examine the lining of the bladder and urethra. A cystoscope consists of a thin hollow tube, which can be rigid or flexible, containing a lens as well as paths for water in and out of the bladder. This tube is attached to a handle that allows the urologist to control the water flow using valves as well as look inside the bladder. Cystoscopy can be used to diagnose problems of the bladder and urethra as well as take tissue samples. Cystoscopes are also used to perform a transurethral resection of the prostate to treat enlarged prostate.

  • The rigid cystoscope was invented 1878. Frankly, the design hasn’t changed much since then. The design is bulky, intimidating to patients, and requires two hands to operate. Also, rigid cystoscopy requires patients to undergo general anesthesia to perform. This is an area with a lot of room for design improvement.

  • It was my goal to create the next generation green light cystoscope to be used while patients are under conscious sedation. This cystoscope handle needed to accommodate a cutting edge widget photon engine, provide in and out water connections, water valve control, accommodate a 24F sheath, and be suitable for left and right hand use. The cystoscope also had to be injection moldable and strong enough for typical use.

A typical rigid cystoscope.

The Design Process

 

Design Inspiration

I wanted my device to be sleek, clean, smooth, and nonthreatening. I created the moodboard below to convey these sentiments.

 Early Sketches

I started creating cystoscope designs, going through several iterations before finalizing my design.

 Final Sketches

After going through many iterations of design, I settled on the sketches below. I designed a cystoscope that could be used with an underhand or overhand grip, left- or right-handed. The water flow is controlled by knobs, and the design includes a soft-touch grip on the front side (shaded in blue).

 

Final CAD Model

I modeled the cystoscope in Fusion 360. Below is a 360 degree view of the final 3D model.

 

A Design Analysis

Finite Element Analysis

Performing an FEA on the cystoscope design yielded a safety factor greater than 2 for a 40N force applied at the tip of the sheath.

Labor, Burden, and Materials

I conducted an LBM cost analysis, which resulted in a final assembly cost of $15.26, cheap enough to be disposable.