Left Ureteroscopy, Stone Retrieval with Basket, and Stent Replacement

Abstract

Urolithiasis is one of the most common and costly benign urologic conditions in the United States. While there are many options for managing urolithiasis ranging from conservative medical expulsive therapy to shockwave lithotripsy to percutaneous nephrolithotomy, ureteroscopy with laser lithotripsy is one of the most frequently performed minimally invasive urologic surgeries for treatment. In this video, we present a case of a patient with a ureteral stone that was treated with ureteroscopy, laser lithotripsy, and basket stone extraction. As part of the procedure, the patient also underwent a retrograde pyelogram and a ureteral stent exchange.

Keywords

Kidney stones; ureteral stones; urology; ureteroscopy.

Case Overview

Background

Urolithiasis is one of the most common, chronically recurring urologic conditions with an estimated lifetime prevalence of approximately 10% in the United States.¹ Ureteroscopy with laser lithotripsy is one surgical option for urolithiasis, and is usually the standard of care for treatment of symptomatic ureteral stones and proximal kidney stones up to 2 cm in diameter. The goal of ureteroscopy and laser lithotripsy, the procedure depicted in the film, is to render the patient stone-free to prevent ongoing symptoms from the existing stones as well as new stone formation. Approximately 50% of patients who have one kidney stone episode will have another stone within 10 years.²

Focused History of the Patient

The patient is a 65-year-old female who presented to the emergency department with worsening, intractable left flank pain radiating to the left groin and associated nausea and vomiting. She was initially seen at another hospital and diagnosed with a left ureteral stone. She was started on medical expulsive therapy with tamsulosin and opioid pain medication. However, she returned to the emergency department due to recurrent worsening pain. She had a history of one prior episode of kidney stones and was able to successfully pass it on her own without surgical intervention. She had a non-contrast CT scan of the abdomen and pelvis that demonstrated a ureteral stone. Her American Society of Anesthesiologists (ASA) score was I (a normal healthy patient). She was not on any anticoagulation.

Her laboratory studies were overall normal. Her white blood cell count was 8.06 K/uL and creatinine was 0.66 mg/dL. Estimated glomerular filtration rate was >90 mL/min/1.73 m². No urinalysis was obtained as it was misplaced by the lab. A urine culture revealed no bacterial growth.

She underwent a left ureteral stent placement for pain management and was then scheduled for elective definitive left ureteroscopy and laser lithotripsy a few weeks later.

Physical Exam

She was afebrile and had normal blood pressure and heart rate. On exam, she was uncomfortable appearing. She had left upper quadrant abdominal tenderness and left costovertebral angle tenderness. Other exam findings were unremarkable.

Imaging

The patient underwent a non-contrast CT scan which demonstrated a 5.1-mm left proximal ureteral stone with associated hydronephrosis. There were also two non-obstructing stones in the left midpole, which were 2.4 mm and 2.1 mm in diameter. At the time of left ureteral stent placement, she underwent a left retrograde pyelogram, which demonstrated a filling defect in the known location of the stone and mild renal pelvis dilation.

Natural History

The majority of ureteral stones <1 cm will pass on their own within a 6 week window.³ Current guidelines recommend a maximum of 6 weeks as an adequate trial of stone passage in order to avoid permanent renal damage from prolonged obstruction. In patients with recurrent renal colic uncontrolled by oral pain medications, intractable nausea and vomiting, and/or repeated emergency department visits for symptoms, surgical intervention is the appropriate next step, whether placement of a ureteral stent to decompress the system or primary ureteroscopy to address the stone.

Options for Treatment

The American Urological Association (AUA) guideline on surgical management of kidney stones offers three options for management of proximal ureteral stones: trial of passage with medical expulsive therapy, extracorporeal shockwave lithotripsy, or ureteroscopy.⁴ Medical expulsive therapy is an option for stones up to 1 cm in diameter. Patients may try to pass the stone for up to 6 weeks, and follow up imaging may be obtained if it will change recommendations for further management. In patients who do not pass the stone within the 6-week window and require definitive surgical treatment, ureteroscopy has the best stone-free rates.

Rationale for Treatment

The goal of any surgical treatment of kidney or ureteral stones is to render the patient completely stone-free. Residual stone fragments (<4 mm) have been theorized to become a nidus for new stone formation or may lead to future emergency department visits and reoperation. Though recent data from a decision analysis suggest that over a 3-year window, approximately 55% of <4-mm residual stone fragments can be safely and cost-effectively observed.⁵

Discussion

Urolithiasis is a painful and costly benign urologic condition that most commonly affects working-age people with peak incidence from 20 to 60 years. There are many options for treating urolithiasis ranging from conservative management (e.g. medical expulsive therapy) to complex endourologic procedures such as percutaneous nephrolithotomy. The choice of procedure generally depends on the stone size and location, as well as other patient-related factors such as anatomy. The frequency of ureteroscopy as treatment for urolithiasis is rising in the United States. One recent study of patients from a large commercial insurance database and from Medicare demonstrated that approximately 250,000 ureteroscopies were performed in 2019, with enormous increases in volumes of the procedure from 2011 to 2019 ranging from 22.6% to 55.6%, depending on the payor.⁶

Ureteroscopy is typically performed under general anesthesia with a laryngeal mask airway. In selected patients deemed too high risk for general anesthesia, it may also be performed under spinal anesthesia. The procedure starts with cystoscopy to evaluate the bladder and placement of a safety guidewire through the ureteral orifice to the level of the kidney, with confirmation on fluoroscopy. American Urological Association guidelines recommend use of a safety guidewire to ensure full access in the case of ureteral trauma. Both flexible and semirigid (short and long) ureteroscopes are available. Semirigid ureteroscopes are generally used for distal ureteral stones, while flexible scopes offer access to the entire renal collecting system and ureter. As the goal of ureteroscopy is to render the patient stone-free, complete visualization of the renal and ureteral systems is crucial to ensure that no stones are left behind. In patients with distal stones, we will start with the semirigid ureteroscope to treat the distal stone, then switch to the flexible ureteroscope to treat or retrieve proximal stones or any residual stone fragments. We typically use saline irrigation and increase the pressure to between 150 mmHg to 250 mmHg. We use a Thermedx system to provide a standardized, consistent fluid pressure through the scope. Other options include a single action pump, which is hand-operated but may provide less consistent pressures. 
In cases with larger stone burden (e.g., 1–2-cm stones), some endourologists elect to place a hydrophilic ureteral access sheath in order to reduce the fluid pressure in the kidney, improve visibility, and facilitate safe repeated access to the ureter and proximal collecting system. Avoiding prolonged intrarenal fluid pressures helps to reduce the risk of hemorrhage, infection, sepsis, collecting system perforation, or fluid absorption.⁷ Though ureteral access sheaths are widely viewed as safe, some surgeons avoid routine use as they can cause some degree of injury from forceful passage or delayed scarring of the ureter.⁸ AUA guidelines recommend using access sheaths to decrease prolonged intrarenal pressures but allow for surgeon discretion about when to use them according to patient and stone characteristics, and their use is frequently decided on a case-by-case basis.

Once the stone is visualized, the decision point becomes whether the stone needs to be broken into pieces that are then extracted with a basket, or if the stone should be dusted, or if the stone can simply be extracted whole with the basket. The size of the ureter, size of the stone, and location of the stone determine which approach is indicated. We use a holmium:YAG laser for kidney stones. There are three laser actions: stone dusting, stone fragmenting, and popcorning. Stone dusting requires low energy at high frequencies; stone fragmentation requires high energy at low frequencies; and popcorning requires both high energy and high frequency. We also used a 1.9-Fr x 120cm Nitinol Zero Tip stone retrieval basket to remove larger fragments.

The decision to place a stent at the end of a ureteroscopy depends on several factors. Current AUA guidelines recommend consideration of stentless ureteroscopy in cases that meet all of the following criteria: no ureteral injury or suspicious of ureteral injury, no anatomic abnormalities or ureteral stricture that would prevent stone fragments from passing, a normal contralateral kidney, normal renal function, and no plans for a second look ureteroscopy.⁴

We send the stones for analysis to guide subsequent recommendations for stone prevention. In cases where there is concern for infection, or if the patient had a prior infection, a stone culture can be sent. To prepare a stone culture, a stone fragment is crushed in a small amount of saline in a specimen cup and sent for low colony count cultures. If the patient develops postoperative fever or sepsis, results from the stone culture may help to guide initial antibiotic therapy.

Regarding follow up for this patient, stone analysis showed 90% calcium oxalate stones. She returned to clinic three months following her procedure with a preclinic renal ultrasound. Imaging showed some small stones up to 7 mm in the lower pole. She had some mild caliectasis in the left renal collecting system. She was advised on increasing her water intake and avoiding oxalate-rich foods and high-sodium foods to prevent further stone formation. She will follow up yearly with renal ultrasounds.

Equipment

• Olympus rigid cystoscope (21 or 22 French) with 30-degree and 70-degree lenses
• Olympus 7.95 French flexible ureteroscope URF-P6
• Boston Scientific 0.035-in straight Sensor guidewire
• Boston Scientific Contour 6-Fr x 24-cm ureteral stent
• Boston Scientific 10-Fr dual lumen catheter
• Boston Scientific 1.9-Fr x 120cm Nitinol Zero Tip™ stone retrieval basket
• Stryker Thermedx fluid management system
  

Disclosures

Tullika Garg currently receives research funding from the Flume Catheter Company, LLC. All other authors report no conflict of interest.

Statement of Consent

The patient referred to in this video article has given their informed consent to be filmed and is aware that information and images will be published online.

Acknowledgements

The authors are grateful to the patient who generously consented to participate in this project to educate others about urologic procedures like ureteroscopy.