David Yu

This week, my Clinical Immersion group had the opportunity to shadow in both the operating room and the urology clinic. It was eye-opening to witness the wide spectrum of procedures urologists perform—from quick outpatient interventions like cystoscopies and vasectomies to complex robotically assisted nephrectomies and reconstructions. I was particularly struck by how central urologists are in addressing patients’ deeply personal and often frustrating urinary concerns. Their expertise brings not only relief but a sense of dignity to the patient experience.

Although many patients referred to urology are older adults, I also had the chance to observe pediatric cases. These presented with a different set of challenges, often involving congenital anomalies, which added another layer of complexity and nuance to urologic care.

Below, I highlight two key observations from this week—one that reflects good design, and another that illustrates opportunities for improvement.

Good Design: Urodynamics Study

Activity
A urodynamic study involves placing two catheters—one in the bladder and one in the rectum—to assess detrusor muscle activity and bladder volume. Saline is gradually infused into the bladder while the patient is asked to hold it in until leakage begins.

Environment
This is performed in a clinic setting, typically by an advanced practice registered nurse (APRN). Real-time pressure and volume data are displayed on a monitor.

Interactions
The APRN monitors bladder filling and instructs the patient to void into a small toilet seat while continuing saline infusion. The patient communicates when they feel the urge to urinate and when they can no longer hold it.

Objects
Catheters, saline bag, computer, toilet seat, pressure/volume monitor.

Users
The APRN conducts the procedure and collects data. Urologists later interpret the findings for diagnosis and treatment planning.

Design Reflection
This process is a strong example of good design. The environment, equipment, and workflow are well-integrated, allowing high-fidelity data collection while keeping the patient relatively comfortable and involved. The collaborative aspect between the patient and provider enables a more nuanced understanding of urinary function. However, it is common for the toilet to not catch all the urine and leaking onto the floor.

Poor Design: Urine Collection for Urinalysis and Culture

Activity
Patients are instructed to self-collect a midstream urine sample. Ideally, they clean the genital area, retract the foreskin if applicable, void the initial stream into the toilet, and collect the final 10% into the provided cup.

Environment
This process occurs privately in a bathroom with no staff supervision or feedback.

Interactions
The urologist or nurse verbally instructs the patient on how to collect the sample. The nurse provides the collection cup and directs the patient to the restroom. The patient completes the process alone.

Objects
Simple urine collection cup.

Users
The patient is solely responsible for collecting the sample; medical staff have no role in quality control once the patient enters the bathroom.

Design Reflection
This process exemplifies poor design. Contamination is common due to unclear or inconsistently followed instructions, which can result in false positives or the need for repeat cultures. This delays diagnosis and treatment while consuming valuable appointment time for re-education. The reliance on verbal instructions—often given quickly and under time pressure—adds variability, especially given differences in health literacy among patients.

Opportunities for Improvement
A redesigned collection device or instructional system (e.g., visual guides, videos, or physical aids in the bathroom) could standardize the process and improve sample integrity. Automating or streamlining patient education through better tools could allow providers to focus more on care delivery.

Primary Data

This week is focused on gaining exposure to the variety of surgical procedures in urology. Throughout the week, I observed procedures including cystourethroscopies, ureteral dilations, robotic prostatectomy, and radical cystectomy with ileal conduit. These procedures last from 15 minutes up to 7 hours. Observing the variety of procedures within urology was an eye-opening experience. Similarly interesting was observing the various devices used for different procedures, including ureteral dilators, Bookwalter retractors, and the cutting-edge Da Vinci SP robotic system.
While observing the 7-hour-long radical cystectomy with ileal conduit, I noticed two staplers that the surgeons used to isolate the ileal conduit from which a stoma is created. Radical cystectomy consists of taking out the entire malignant bladder, re-anastomosing the ureters to a conduit resected from a section of the ileum, and creating a stoma that drains through the abdominal wall using the conduit. To resect the ileum, the GIA (gastrointestinal anastomosis) and TA (thoracoabdominal) staplers are used. The GIA stapler performs cutting and stapling simultaneously. It isolates the ileal conduit and re-anastomoses the remaining bowel with one instrument. Once the conduit is resected from the ileum with both ends open, the TA stapler closes one end of the conduit, allowing the other end to be turned into a stoma. These two instruments allow the procedure to be done more efficiently than hand-sewn anastomosis.

Secondary Data (Literature)

Simonato et al. (2023) conducted a retrospective comparative study of the literature comparing hand-sewn and stapled intestinal anastomosis. This paper showed that grade I incidence (minor incidents such as mild fever) was higher in the hand-sewn group than in the stapled group. However, there were no differences in the return of bowel function, and hand-sewn anastomosis was associated with shorter hospital stays. They concluded that both hand-sewn and stapled techniques are equally safe and effective. However, hand-sewn anastomosis is significantly cheaper than stapling (€0.40 vs €350).

Commercial Patents

While I couldn’t identify patents for the GIA and TA staplers specifically, the parent company Medtronic (formerly Covidien) holds a variety of patents for surgical staplers, including US20170119388A1 and US11478245B2. These patents do not feature specifically the detachable body design in the GIA or the retaining pin design in the TA. The figures show the device design and its refillable cartridges.

Desirability

Primary Observation:

Activity – Laser lithotripsy

Environment – Hospital OR

Interactions – Surgeon performs the lithotripsy with pulsatile laser under live video

Objects – Ureteroscope, optic fiber, irrigation system, camera, endoscopic basket

Users – Surgeons

Laser lithotripsy is commonly performed to remove kidney stones and stones that are stuck in the ureter. It consists of using a pulsatile laser beam to blast the kidney stones into smaller pieces that can then be removed using an endoscopic basket. During my observation, I found that the laser is effective at breaking up the stones into smaller pieces. However, the retrieval of the stones can be time-consuming and cause mucosal damage on the ureters from the metal basket scraping on the mucosa.

Secondary Observation: 

One of the devices aiming to improve stone retrieval is the CVAC system by Calyxo. This is an ureteroscope integrated with an irrigation and vacuum system that performs stone reduction and removal in one device. According to latest data from the AUA 2025 conference, the CVAC system resulted in lower intrarenal pressure, fewer device complications, and excellent stone clearance compared to the conventional method of FANS (Flexible and Navigable Ureteric Access Sheath).

Feasibility

Patents:

US20240358911A1: System and method for guided removal from an in vivo subject. Filed by Calyxo Inc.

US11116530B2: Devices and methods for minimally invasive kidney stone removal by combined aspiration and irrigation. Filed by Calyxo Inc.

Commercial Solutions:

Some products that aim to improve lithotripsy include:

1. ClearPetra Vacuum-Assisted Ureteral Access Sheath
2. Calyxo CVAC Aspiration System

Viability

Market Analysis:

Companies innovating in the stone retrieval realm include ClearPetra, Calyxo, Cook Medical, and Boston Scientific. Their devices each have different features and varying cost between $100 and $200 for the basket-style devices. Prices for the Caylxo and ClearPetra systems are unclear. The estimated direct treatment cause is estimated to reach 4.1 billion dollars by 2030.

Total Addressable Market (TAM) = # units/year x product cost

Laser lithotripsy is performed over 300,000 times a year in the US.

TAM = 300,000 x ~$500 = $150M

Works Cited:

Roberson, D., Sperling, C., Shah, A. et al. Economic Considerations in the Management of Nephrolithiasis. Curr Urol Rep 21, 18 (2020). doi: 10.1007/s11934-020-00971-6

Fried, N. Recent advances in infrared laser lithotripsy. Biomed Opt Express. 2018 Aug 30;9(9):4552-4568. doi: 10.1364/BOE.9.004552

This week, I spent more time observing a mix of OR procedures and clinic visits. The time spent allowed me to evaluate my previous kidney stone retrieval idea more critically. While laser lithotripsy is a common procedure done by urologists, there are other common procedures that the patients interact with more directly such as urine collection. During my interview with a urology resident, he estimated that 1 in 3 patients will require a urine collection and the samples are often contaminated. According to one study on collection of midstream clean-catch urine in the emergency department, the contamination rate is over 30% [1]. With this new insight, I re-evaluated the desirability, feasibility, and viability of the vacuum-based kidney stone idea.

In terms of desirability, I believe that a more efficient way of extracting kidney stone fragments is still very relevant and remains in need. The stone extraction device’s feasibility is more challenging than the standardized urine collection idea upon more research. Stone extraction devices require a high level of technological maturity and existing products such as Calyxo CVAC and CleanPetra are already being utilized at multiple academic institutions. Viability wise, the market size for kidney stone removal is still very large. However, based on how common urine collection is in not just urology but also ob/gyn, nephrology, and various other specialties, there may be more abundant opportunities for a clean-catch urine collection device if proven useful.

Storyboard of Midstream Clean Catch Urine Collection for Women

Scene 1: Jane, 45, visits her clinic with UTI symptoms. 

Scene 2: Jane is given a cup and a wipe to catch the midstream urine

Scene 3: In a poorly equipped restroom, Jane tries to follow the instructions. Unable to see or aim well, urine flows over her skin into the cup. 

Scene 4: She submits the sample. Lab results show contamination. 

Scene 5: Jane is told that her culture is contaminated. She is prescribed a broad-spectrum antibiotic as a precaution. This leads to more systemic side effects such as diarrhea and yeast infections.

Scene 6: She returns for further testing, leading to delayed care and increased frustration. She may have to pay for an additional antibiotic after the new cultures return.