bubble_chart Overview

The vast majority of ureteral stones originate from the kidneys, including kidney stones or fragments that descend after extracorporeal shock wave lithotripsy. Since urinary salt crystals are more easily expelled into the bladder with urine, primary ureteral stones are extremely rare. When predisposing factors such as ureteral strictures, diverticula, or foreign bodies are present, urine stasis and infection can promote the formation of ureteral stones. Most ureteral stones are single, with similar incidence rates on the left and right sides. Bilateral ureteral stones account for approximately 2–6%. Clinically, they are most common in young adults, with the highest incidence occurring between the ages of 20 and 40. The male-to-female ratio is 4.5:1, and the stones are most frequently located in the lower segment of the ureter, accounting for about 50–60%. The urinary flow above a ureteral stone can cause obstruction and hydronephrosis, endangering the affected kidney. In severe cases, renal function may gradually deteriorate.

bubble_chart Clinical Manifestations

The symptoms of ureteral stones and kidney stones are basically similar. The size of the stone is not necessarily proportional to the degree of obstruction, hematuria, and pain. Stones impacted or moving downward in the middle or upper part of the ureter often cause typical colicky pain on the affected side and microscopic hematuria. The pain may radiate to the inner thigh, testicles, or labia. It is often accompanied by nausea and vomiting, and sometimes hematuria is visible to the naked eye. The intramural segment of the ureter near the bladder is the narrowest, making it prone to stone retention. Since the muscles of the lower ureter are connected to the trigone of the bladder and directly attached to the posterior urethra, symptoms such as frequent urination, urgency, and dysuria are common. Larger stones that do not obstruct urine flow may only cause dull pain, and hematuria is mild. In cases of ureteral stone obstruction in a solitary kidney, bilateral ureteral obstruction, or reflex anuria due to unilateral obstruction, acute anuria or even renal insufficiency may occur.

bubble_chart Diagnosis

The correct diagnosis of ureteral stones not only confirms the presence or absence of stones but also determines the size and location of the stones, the function of both kidneys, the degree of hydronephrosis, and the presence of infection. Typical renal colicky pain and hematuria are important diagnostic clues. During pain episodes, there is tenderness and percussion pain in the costovertebral angle. Larger stones in the lower ureter of females can be palpated in the vaginal fornix.

Over 90% of ureteral stones can be visualized on a plain abdominal X-ray, with calcium oxalate stones showing the best contrast. However, differentiation is needed from calcified abdominal lymph nodes, pelvic phleboliths, appendiceal fecaliths, and bone islands. Intravenous urography primarily assesses the location of the stone, kidney function, and the presence of hydronephrosis. When necessary, seasonal epidemic large-dose urography and radionuclide renography can further evaluate kidney function. Cystoscopy and ureteral catheterization may encounter obstruction at the stone site, and a plain X-ray showing calcification at the same level as the catheter confirms the diagnosis of a ureteral stone. For radiolucent stones, retrograde pyelography using air as a contrast agent can reveal the stone's presence. Additionally, CT and B-mode ultrasound are helpful in diagnosing stones not visible on plain X-rays.

bubble_chart Treatment Measures

The treatment of ureteral stones includes symptomatic treatment, Chinese medicinals therapy, extracorporeal shock wave lithotripsy, endoscopic stone removal, and surgical stone extraction.

(1) Symptomatic treatment primarily involves controlling renal colicky pain. After a clear diagnosis is made, atropine 0.5mg and pethidine 50mg can be administered intramuscularly. The painful area can also be treated with hot compresses or acupuncture. Subcutaneous procaine block (after a skin test) can be performed on sensitive areas of the lower back. Alternatively, heart pain-relieving medications or indomethacin suppositories can be used rectally.

(2) Chinese medicinals for stone expulsion therapy are suitable for stones with a diameter of less than 1cm, oval shape, smooth surface, and no hydronephrosis on pyelography. Treatment principles and medications include clearing heat and draining dampness, such as Christina Loosestrife and Sea Jin Sand; clearing heat and removing toxins, such as Phelloendron Bark, Lonicera, and Forsythia; invigorating blood and resolving stasis, softening hardness and resolving dampness, such as San Leng and E Zhu; tonifying the kidney, such as Cassia Bark, Aconite Lateral Root, and Desertliving Cistanche; tonifying qi and tonifying blood, such as Tangshen and Astragalus Root. There are also various stone-expelling infusion granules for convenient use.

(3) Extracorporeal shock wave lithotripsy (ESWL) uses X-ray localization with a Dornier-type machine and has been expanded from treating upper ureteral stones to mid and lower ureteral stones. For upper ureteral stones, a semi-recumbent oblique position is preferred. For stones overlapping the iliac wing, a prone position should be used; for lower ureteral stones, a semi-sitting position with increased voltage can achieve a certain success rate. Although stones along the entire ureter can be fragmented with ESWL, challenges such as difficulty in localization for small stones or obese patients, deep location, and high energy consumption make ureteral stone fragmentation relatively more difficult compared to renal stones, with overall lower effectiveness. Therefore, accurate localization during shock wave therapy is crucial. For difficult cases, excretory urography or cystoscopic retrograde catheterization and contrast imaging can assist in localization. Pushing the stone back into the renal pelvis before lithotripsy is ideal. Stones that allow contrast medium to pass through are often easier to fragment and expel. Antagonism, even for small stones with significant upstream hydronephrosis, especially when accompanied by periureteritis or when retrograde catheterization cannot reach below the stone, often results in poor ESWL outcomes.

For smaller lower ureteral stones, ureteral dilation, stone basketing, or meatal incision can be performed via cystoscopy. In recent years, ureteroscopic stone removal or laser/ultrasonic lithotripsy has been applied, with reported success rates of 40–78%. However, it is noteworthy that severe complications such as perforation or tearing can occur during the procedure.

(4) Surgical stone extraction is indicated for: ① ureteral strictures; ② bilateral or unilateral ureteral stones with impaction and infection causing anuria; ③ large stones with severe hydronephrosis and poor renal function; ④ failed ESWL localization or treatment; ⑤ cases where tumors or subcutaneous nodes cannot be clinically ruled out; ⑥ economic factors. A plain X-ray of the urinary tract should be taken 2 hours before surgery for localization.

For larger lower ureteral stones in female patients, the stones can sometimes be palpated through the vaginal fornix and expelled via tuina.