The RELIEF™ Ureteral Stent - Assessment of Retrograde Urinary Reflux and Distal Coil Bladder Position

Traditional ureteral stents are commonly used in practice to relieve renal obstruction or as a scaffold to promote healing after endoscopic or open/ laparoscopic surgeries involving the ureter. However, there are many morbidities associated with stent placement either due to bladder irritation or backflow of urine to the kidney. The most commonly reported symptoms include urgency, urinary frequency, dysuria, incontinence, hematuria, suprapubic discomfort, and fever due to urinary tract infections and flank pain, which can occur in up to 80% of stented patients. Sometimes, the symptoms are poorly tolerated and can negatively affect patients' quality of life. Shao et al have studied the relationship between bladder filling and the renal pelvic pressure (RPP) in stented patients, which revealed that RPP increased mildly during bladder filling and increased dramatically during voiding, indicating urinary reflux, and thus encouraging early stent removal. Another study showed that patients with stents whose distal coils cross the midline are at higher risk of post-stenting morbidities. Replacement of the distal portion of the ureteral stent with a thin material may reduce bladder irritative symptoms and allow the ureterovesical junction to coapt, thereby eliminating urinary reflux.

The Ureteral Stent Company, LLC (USC) is developing the RELIEF™ Ureteral Stent, a single use, disposable ureteral stent (US) device that will provide the traditional function of allowing the passage of urine from the kidney to the bladder with new design enhancements to improve patient care:

• A low-profile tether through the intramural ureter segment, minimizing the potential of urinary reflux
• Polymeric solid distal coil that minimizes the potential for coil positioning on the trigone, reducing the potential for associated bladder spasms and pain.

It is hypothesized that the RELIEF stent will offer the same function of traditional ureteral stents with the added benefits of minimizing the urinary reflux and reducing irritative bladder symptoms.

Inclusion criteria

• Ureteral stone of 5-25 mm measured on plain abdomen X-ray KUB (Kidney Ureter Bladder) or CT (computed tomography).
• Upper or middle third ureteral stricture.

Exclusion criteria

• Patients with distal ureteral obstruction
• Patients with urinary reflux
• Patients requiring bilateral surgical stone management procedure
• Intraoperative exclusion: Based on the urologist's discretion, if trauma has been induced to the distal ureter due to ureteroscopy maneuvers, these patients will be excluded.