Ureteroscopy, Laser Lithotripsy, and Stent Replacement for an Obstructing Left Proximal Ureteral Stone with Forniceal Rupture

Abstract

The case demonstrates the use of ureteroscopy with laser lithotripsy in the treatment of an obstructed left proximal ureteral stone with forniceal rupture. The patient presented to the emergency department with the signs and symptoms of a ureteral stone and was taken for imaging and a diagnostic ureteroscopy. Following confirmation of the diagnosis, the patient was scheduled for ureteroscopy with laser lithotripsy. A guidewire was placed, followed by visualization with a retrograde pyelogram and a subsequent flexible ureteroscopy. Laser lithotripsy was performed to fragment the stone. Following fragmentation, the renal pelvis and calyces were visualized to examine for retrograde movement of stone fragments. A confirmatory retrograde pyelogram was then performed, followed by placement of a temporary stent for fluid drainage. The patient was then discharged with opioids for pain medication and prophylactic antibiotics to prevent urinary tract infections and the subsequent risk of urosepsis.

Keywords

Urolithiasis; nephrolithiasis; flexible ureteroscopy; laser lithotripsy; fragmentation; stent.

Case Overview

Background

The patient presents with an obstructing left proximal ureteral stone with forniceal rupture. The incidence of renal calculi is estimated to be 8.8% in North America with an increasing global trend.⁴ The majority of stones occur between the ages of 30–69 years in males and between 50–79 years in females.⁴ Additionally, it has been theorized that the increased incidence of stones is due to the detection of asymptomatic calculi via advanced imaging techniques.⁴ Finally, there is an increased incidence in men with a male:female ratio of 2–3:1, though this disparity is also decreasing.⁴ Left untreated, large stones obstructing the flow of urine may lead to increased pressure in the kidney resulting in hydronephrosis, renal atrophy, irreversible damage, and perinephric abscesses in the setting of infection.² One method for the treatment of these stones, which is demonstrated in the video, is ureteroscopy with laser lithotripsy followed by temporary stent placement. This procedure involves six key steps:

1. A retrograde ureteropyelogram is performed to visualize the stone on X-ray.
2. A ureteroscope is then inserted to visualize the stone.
3. Lithotripsy is performed with the use of a laser to break apart the stone into smaller fragments capable of being passed in the urine.
4. Renoscopy is then performed to visualize the calyces for further stone fragments that would disrupt urine flow.
5. A second retrograde pyelogram is then performed to ensure clearance of the stone and fragments.
6. Finally, a temporary stent is placed to assist in postsurgical fluid drainage.⁵

History of Presenting Illness

A 76-year-old male presented to the emergency room two weeks prior to ureteroscopy with lithotripsy. Patient was taken for ureteroscopy and stent replacement. Following two weeks of antibiotics and decompression via an internal stent, the patient is now presenting for definitive management with left ureteroscopy, lithotripsy, and stent replacement.

Physical Exam

Typical exam findings include severe pain, often along the renal/costovertebral angle. The pain usually has a sudden onset and may radiate to the groin or genitalia. It has been described as one of the worst pains patients have ever felt. There may be additional urinalysis findings including hematuria, or fever and positive culture in the setting of infection. Additionally, other systemic symptoms including nausea and vomiting are common.²

Imaging

The standard of care imaging technique for urolithiasis remains the nonenhanced CT scan. In addition to detecting renal stones, the CT scan can also identify other sources of abdominal pain for a definitive diagnosis. The unenhanced CT has a sensitivity of 96–100% and a specificity of 92–100%. Additionally, a helical CT scan can detect all types of renal and ureteral stones, excluding indinavir stones. Follow up imaging includes retrograde pyelograms and ureteroscopy.⁴

Natural History

There are numerous substances and causes of kidney stones. Some factors include conditions like dehydration or anatomical vulnerabilities such as ureteropelvic junction obstruction or a horseshoe kidney.² Composition of the stone varies, with the most common stones being calcium-based. Other stones include uric acid, cysteine, and xanthine.² Most small kidney stones less than 5 mm will pass within a few days with the assistance of increased fluid intake. For larger stones and those that do not pass, urine flow may be obstructed, leading to hydronephrosis, renal atrophy, irreversible damage, and perinephric abscesses in the setting of infection.²

Options for Treatment

Asymptomatic, smaller stones may pass on their own with only expectant management.² For larger stones that are unable to pass, medical intervention is required. The first option is shock wave lithotripsy. This treatment involves using a device placed outside the body sending shock waves inside the urinary system targeting the stone. Focusing the waves on the stone allows for stone fragmentation and subsequent removal via urinary flow. While this procedure is effective, it can induce additional harm on the body. Adverse outcomes include but are not limited to acute renal injury and long-term development of hypertension and diabetes mellitus.³ A second option for treatment of urolithiasis is ureteroscopy. This procedure involves the retrograde visualization of the urinary system using a rigid, semi-rigid, or flexible endoscope. In addition to visualization, the use of a double-lumen catheter allows passage of a laser for lithotripsy within the ureter, as was the case with this patient. One disadvantage of this technique is the common requirement for placement of a ureteral stent to prevent obstruction caused by edema or stone fragments. This stent can cause considerable discomfort to the patient. A third and final procedure for the treatment of urolithiasis is percutaneous nephrolithotomy. This procedure requires forming a surgical access point to the urinary system through the skin. A nephroscope and an instrument for stone removal can be passed using this surgical opening. The stone is then removed using suction, graspers, or basket extraction. The disadvantage to this technique is that it is considered the most invasive due to the surgical access point through the skin.³

Rationale for Treatment

The treatment goal is to remove the stone, allowing successful passage of urine through the urinary system and out of the body. Treatment also aims to decrease the risk of the numerous adverse effects noted previously.²

Special Considerations

There are patient populations where ureteroscopy is contraindicated and not a viable option. Patients with active urinary tract infections should be treated, and there should be confirmation of resolution of the infection prior to ureteroscopy, as the presence of a urinary tract infection during a ureteroscopy is the number one predictor of a postoperative urinary tract infection. Patients on anticoagulant therapy or at risk for excessive bleeding may also not be good candidates for ureteroscopy. Anatomical barriers may also exclude patients from ureteroscopy. These include but are not limited to ureteral kinking and obstructions or narrowings of the urethra, ureteral orifice, prostate, trigone, or ureter. Finally, secondary consideration should also be given to patients who are pregnant and may not safely tolerate anesthesia.⁵

Discussion

While ureteroscopy has been around for over half a century, recent scientific advances have expanded the procedure’s scope of practice and capabilities. There are three main categories of ureteroscopes: rigid, semi-rigid, and flexible. As the name implies, rigid scopes severely restrict the range of motion and field of view. Semi-rigid ureteroscopes consist of a pliable outer metallic covering that allows for a slightly increased range of motion. Flexible ureteroscopes, as was used in this procedure, have the largest range of motion and maneuverability.⁶ In addition to the type of ureteroscope, advancements have allowed for narrower shaft diameters, greater distal tip deflection for increased field of view, and working channels, such as the double-lumen catheter.⁶

Flexible ureteroscopes have gained popularity in recent years due to their unique advantages regarding the field of view. The field of view is reflected in the deflection capacity, which further consists of primary deflection and secondary deflection. Primary deflection is the range of view a scope can obtain from a neutral position. Secondary deflection is the obtainment of a further field of view due to additional deflection from the pliability of the flexible ureteroscope.⁶

In the past, ureteroscopes primarily relied on fiber-optic imaging for visualization. However, the practice is now shifting towards digital imaging. Digital imaging involves a digital sensor on the tip of the ureteroscope, which is attached to a sensor located more proximal in the scope. Compared to fiber optics, digital ureteroscopes offer unique advantages, including higher-definition images, autofocus capabilities, and digital magnification.⁶ Due to the unique advantages of this technology, digital ureteroscopes have demonstrated quicker setup, less overall weight, more durability, larger working channels, and an increased capacity for maneuverability. However, compared to the traditional fiber-optic scopes, the digital scopes cost more upfront and have a larger average diameter.⁶ 

In addition to ureteroscopes, it is a national consensus that a guidewire should be used in these cases. A guidewire is a safety technique that allows for the passage of a wire past obstructions. There are two general types of guidewires: slippery guidewires and stiff guidewires. The slippery guidewire is highly flexible and minimizes trauma to the uroepithelial tract. Their disadvantage is that they are less able to push through obstructions due to their increased flexibility. Stiff guidewires provide the opposite risks and benefits. They are more traumatic to the uroepithelium but can push past obstructions. Recently, a third type of guidewire has been developed to offer both benefits by being semi-rigid. Finally, access sheaths and catheters can be utilized to maintain proper dilation of the urinary tract.

Once the physician has access to the stone, lithotripsy is accomplished via electrohydraulic, pneumatic, ultrasonic, or laser lithotripters. Laser lithotripters are the most common and were used in this case. The laser fibers come in varying sizes, with smaller lasers being more flexible and less damaging to the scope. In contrast, larger fibers have greater fragmentation ability over a quicker time frame. As mentioned, the greatest risk associated with laser lithotripters is damage from the ureteroscope.6 The most important clinical complication regarding the use of laser lithotripters is the possibility of retrograde movement of stone fragments into the proximal ureter and renal calyces where they may again be impacted.⁶

The primary complications of ureteroscopy with lithotripsy are infection, bleeding, and ureteral injury. Of the bleeding risks, the primary outcomes were subcapsular renal hematoma and perirenal hematoma. However, these complications were exceedingly rare, and flexible ureteroscopy can still be considered a viable treatment for some patients on anticoagulant therapy.¹

The most common adverse outcome after ureteroscopy and lithotripsy is postoperative infections. They tend to clinically present with flank pain, costovertebral tenderness, nephritis, high white blood cell counts, and high C-reactive protein. Risk factors for postoperative infections included the female sex, diabetes mellitus, preoperative positive urine cultures, operation duration, stone dimensions, and preoperative ureteric stent placement.¹ To prevent postoperative infections, antibiotic prophylaxis is commonly administered, as was the case in this procedure. 

Ureteral injury is another common complication after ureteroscopy and lithotripsy. Ureteral injury is graded based on the Traxer Ureteral Injury Scale, which grades the injury from zero, or no injury and only petechiae, to four, ureteral avulsion with loss of continuity. Higher-grade injuries, those graded two to four, pose a higher risk for ureteral strictures postsurgery. These strictures can increase the risk of further complications, including hydronephrosis.¹

Mortality is rare in ureteroscopy with lithotripsy, with most deaths occurring due to the development of urosepsis postoperatively. To lower the mortality rate, the following set of guidelines were developed:

• Only operate on patients with sterile preoperative urine.
• Utilize ureteral access sheaths.
• Irrigate with caution as irrigation can push bacteria proximally in the urinary tract.
• Do not exceed operative times of 120 minutes.

Carefully monitor patients postoperatively for the complications discussed previously.¹

Equipment

The major equipment required for this procedure includes a ureteral catheter, guidewire, cystoscope, laser lithotripter, and ureteral stent.

Disclosures

Nothing to disclose.

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.