Antibiotic Irrigation and Suction Ureteral Access Sheath in RIRS

Subject:

The present study aims to investigate the effects of gentamicin-containing irrigation and the use of a suction ureteral access sheath during retrograde intrarenal surgery (RIRS) on postoperative infectious complications.

Objective:

The aim of this study is to evaluate the independent and combined effects of gentamicin irrigation and a suction ureteral access sheath on postoperative infectious complications following RIRS.

Retrograde intrarenal surgery (RIRS) is a commonly used minimally invasive treatment modality for renal stones, particularly for stones up to 20 mm. Although RIRS is generally considered safe and effective, postoperative infectious complications remain an important clinical concern. Fever, urinary tract infection, systemic inflammatory response syndrome (SIRS), and sepsis may occur even in patients with negative preoperative urine cultures and appropriate perioperative antibiotic prophylaxis.

A potential mechanism for infectious complications after RIRS is increased intrarenal pressure during endoscopic lithotripsy. Elevated intrarenal pressure may promote pyelovenous and pyelolymphatic backflow, allowing bacteria, endotoxins, and inflammatory mediators from the collecting system or stone surface to enter the systemic circulation. Therefore, strategies that reduce bacterial contamination within the renal collecting system and improve intrarenal drainage may help decrease postoperative infectious morbidity.

This study is designed to evaluate two intraoperative strategies intended to reduce infectious complications during RIRS. The first strategy is local antibiotic irrigation using gentamicin-containing saline solution. Gentamicin will be added to the irrigation fluid as a local intraoperative measure rather than as a systemic treatment. This approach is intended to reduce bacterial contamination within the collecting system during lithotripsy. All patients will also receive standard systemic antibiotic prophylaxis according to routine clinical practice.

The second strategy is the use of a suction-enabled ureteral access sheath. This device is intended to improve fluid evacuation, reduce intrarenal pressure, and facilitate the removal of stone dust, debris, and potentially contaminated fluid during the procedure. By improving drainage from the collecting system, suction-assisted RIRS may theoretically reduce pyelovenous backflow and the risk of postoperative systemic inflammatory or infectious events.

The study uses a 2×2 factorial design, which allows simultaneous evaluation of the independent effects of gentamicin irrigation and suction-enabled ureteral access sheath use, as well as their combined effect. This design is useful because both interventions target different mechanisms that may contribute to infectious complications: local bacterial contamination and elevated intrarenal pressure. The factorial structure will also allow assessment of whether the combination of these two approaches provides an additive or synergistic benefit compared with either intervention alone.

All procedures will be performed under general anesthesia in the lithotomy position using standard endourological techniques. Irrigation will be performed with normal saline under low-pressure conditions. In the gentamicin irrigation groups, 80 mg gentamicin will be added to each 3 L bag of normal saline. In the suction groups, a suction-enabled ureteral access sheath will be used during flexible ureteroscopy. Stone fragmentation will be performed with a holmium:YAG laser using a dusting technique, and a double-J ureteral stent will be placed at the end of the procedure according to the study protocol.

This trial may provide clinically relevant evidence regarding infection-prevention strategies in RIRS. If gentamicin irrigation, suction-assisted access sheath use, or their combination is shown to reduce postoperative infectious complications without compromising surgical success, these approaches may contribute to safer perioperative management in endourological stone surgery.

• Standard Retrograde Intrarenal Surgery (Procedure), also known as Standard RIRS Flexible Ureteroscopy: Standard retrograde intrarenal surgery will be performed under general anesthesia in the lithotomy position. A guidewire will be advanced to the renal pelvis under fluoroscopic guidance, and a ureteral access sheath will be placed when appropriate. Flexible ureteroscopy will be performed, and stones will be fragmented using a holmium laser with the dusting technique. Standard saline irrigation will be used during the procedure.
• Gentamicin Irrigation (Drug), also known as Gentamicin-Containing Irrigation Local Antibiotic Irrigation Intervention Description:: Gentamicin-containing irrigation fluid will be used during retrograde intrarenal surgery. In the gentamicin irrigation groups, 80 mg gentamicin will be added to each 3 L bag of normal saline irrigation solution. This intervention will be used as a local intraoperative irrigation strategy to reduce bacterial contamination within the renal collecting system and is not intended as systemic antibiotic treatment.
• Suction-Enabled Ureteral Access Sheath (Device), also known as Suction UAS Aspiration Ureteral Access Sheath Suction-Assisted Ureteral Access Sheath: A suction-enabled ureteral access sheath will be used during retrograde intrarenal surgery in the suction groups. The device is intended to improve fluid evacuation from the renal collecting system, reduce intrarenal pressure, and facilitate removal of irrigation fluid, stone dust, and debris during flexible ureteroscopy.

Primary outcomes

• Postoperative Fever [Within 48 hours after surgery]: Postoperative fever will be defined as a body temperature greater than 38°C occurring within the first 48 hours after retrograde intrarenal surgery.
• Systemic Inflammatory Response Syndrome [Within 48 hours after surgery]: Systemic inflammatory response syndrome will be defined as the presence of at least two of the following criteria: body temperature greater than 38°C or less than 36°C, heart rate greater than 90 beats/min, respiratory rate greater than 20 breaths/min, or white blood cell count greater than 12,000/mm³ or less than 4,000/mm³.
• Sepsis [Within 48 hours after surgery]: Sepsis will be defined as systemic inflammatory response syndrome in the presence of confirmed or suspected infection after retrograde intrarenal surgery.

Secondary outcomes

• Stone-Free Rate [4 weeks after surgery]: Stone-free status will be evaluated using non-contrast computed tomography. Residual fragments of 4 mm or less will be considered clinically insignificant.
• Change in White Blood Cell Count [Baseline and within 48 hours after surgery]: White blood cell count will be assessed before and after surgery to evaluate postoperative inflammatory response.
• Change in Serum Creatinine [Baseline and within 48 hours after surgery]: Serum creatinine levels will be assessed before and after surgery to evaluate renal function changes.
• Urine Culture Positivity [Within 48 hours after surgery]: Postoperative urine culture results will be evaluated to identify urinary tract infection and causative microorganisms.
• Blood Culture Positivity [Within 48 hours after surgery]: Postoperative blood culture results will be evaluated in patients with suspected systemic infection to identify bloodstream infection and causative microorganisms.

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Patients scheduled for retrograde intrarenal surgery (RIRS) due to kidney stones
* Male and female patients aged 18 years or older
* Patients who voluntarily sign the informed consent form
* Patients with sterile urine culture or whose preoperative infection has been treated and urine culture has become sterile

Exclusion Criteria:

* Patients with active urinary tract infection before surgery
* Patients with chronic kidney disease
* Pregnant patients
* Patients with allergy to aminoglycoside-group drugs used in the study protocol, specifically gentamicin
* Cases in which the ureter cannot be accessed and the procedure is postponed by placing a double-J stent instead of performing dilation

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