Introduction
Bladder calculi are an uncommon cause of illness in most Western countries, but they result in specific symptoms and are a significant source of discomfort. This article discusses the diagnosis and current management techniques for vesical calculus disease.
For excellent patient education resources, visit eMedicine's Kidneys and Urinary System Center and Procedures Center. Also, see eMedicine's patient education articles Cystoscopy, Intravenous Pyelogram, and Blood in the Urine.
History of the Procedure
Bladder stones have been treated both medically and surgically for many centuries. The oldest bladder stone discovered dates back to 4800 BC and was found by archeologists in Egypt around the turn of the 20th century.1 The first literary references to bladder stones date back to a time as early as, or earlier than, the time of Hippocrates.2 More than 23 centuries ago, Hippocrates warned that, "To cut through the bladder is lethal," and part of the Hippocratic oath includes, "I will not cut for stone, even for the patients in whom the disease is manifest; I will leave this operation to be performed by practitioners." His admonition to young physicians was to leave this highly risky and complicated procedure to the purveyors (ie, the lithotomists) of what could only be described as an art.1
Famous historical figures who developed vesical calculi include King Leopold I of Belgium, Napoleon Bonaparte, Emperor Napoleon III, Peter the Great, Louis XIV, George IV, Oliver Cromwell, Benjamin Franklin, the philosopher Bacon, the scientist Newton, the physicians Harvey and Boerhaave, and the anatomist Scarpa.1
Operations to remove bladder stones via the perineum were performed by Hindus, Greeks, Romans, and Arabs. Ammonius (200 BC), Celsus (first century), and the Hindu surgeon Susruta were among the first to write about perineal lithotomy to treat bladder calculi.1 They wrote excellent and sometimes detailed descriptions of the surgery, including preoperative and postoperative care and management.2 In the 1500s, Pierre Franco introduced suprapubic lithotomy.3 Frère Jacques Beaulieu developed the lateral approach to perineal vesicolithotomy in the late 1600s. An itinerant lithotomist with little anatomic understanding but impeccable character, Beaulieu performed the often-lethal procedure in France through the early 1700s. He is remembered by the urologic community as the subject of an old French nursery rhyme, although some have suggested that it was really written as a satirical mockery of the Jacobinic monks whose order was popular in France at the time.4
In an attempt to avoid incisions, another form of surgical treatment, transurethral lithotrity, became more common in the early 1800s. Lithotrity was developed through creative applications of everyday tools. The Egyptian physicians were known to pass large wooden or cartilage cannulas through the urethra, followed by manual aspiration of the stones from the bladder. A popular technique of the 1700s involved passage of a long nail via the urethra; the nail was then struck with a blacksmith’s hammer, fracturing the stone.
Although many other creative and colorful transurethral instruments were developed, technological advancement in the modern era came in the form of the fenestrated lithotrite. This device allowed stones to be grasped and crushed so their fragments could be evacuated from the bladder via glass or metal suction bottles. Sir Philip Crampton was the first to introduce the manual crushing concept in Dublin (circa 1834). However, litholapaxy was not firmly established until Henry J. Bigelow, the famous professor of surgery at Harvard, performed (1876) and popularized (1878) the procedure.1 The mechanical crushing of stones remained popular through the 1960s and 1970s, although it was fraught with complications when performed by inexperienced urologists.5
In the 1950s, endoscopic electrohydraulic lithotripsy (EHL) was first performed in the Soviet Union. Over the next 4 decades, multiple other modalities have been developed and allow safe transurethral or percutaneous stone ablation.6
Problem
Vesical calculi refer to the presence of stones or calcified materials in the bladder (or bladder substitute that functions as a urinary reservoir). These stones are usually associated with urinary stasis, but they can form in healthy individuals without evidence of anatomic defects, strictures, infections, or foreign bodies. The presence of upper urinary tract calculi is not necessarily a predisposition to the formation of bladder stones.
Frequency
The incidence of primary bladder calculi in the United States and Western Europe has been steadily and significantly declining since the 19th century because of improved diet, nutrition, and infection control. In these countries, vesical calculi affect adults, with a steadily declining frequency in children. In the Western hemisphere, vesical calculi primarily affect men who are usually older than 50 years and have associated bladder outlet obstruction. However, bladder calculi remain common in less-developed countries and areas such as Thailand, Burma, Indonesia, the Middle East, and North Africa. Although the prevalence of bladder calculi is declining in these populations, it remains a disease that affects children, among whom the disease is far more common in boys than in girls.6
In 1977, Van Reen published a symposium on idiopathic urinary bladder stone disease.7 Unfortunately, no definitive worldwide data accurately reflect the frequency of bladder calculi. This is mostly because of poor hospital records in developing regions of the world. Despite several studies in countries with a high incidence of the disease, the reporting is not uniform.
Etiology
Bladder outlet obstruction remains the most common cause of bladder calculi in adults. Prostatic enlargement, elevation of the bladder neck, and high postvoid residual urine volume cause stasis, which leads to crystal nucleation and accretion. This ultimately results in overt calculi. In addition, patients who have static urine and develop urinary tract infections are more likely to form bladder calculi. In a study of patients with spinal cord injuries (newly acquired neurogenic bladders) who were monitored for more than 8 years, 36% developed bladder calculi. More recent reports indicate that, because of better care of patients with injured spinal cords, this rate has dropped to less than 10%.
Bladder inflammation secondary to external beam radiation or schistosomiasis can also predispose to vesical calculi.8 The dystrophic calcifications that develop radiotherapy-related bladder and prostate damage might serve as a nidus for stone formation. Congenital or acquired vesical diverticula may serve a reservoir of urinary stasis, leading to stone formation. Other rare anatomic abnormalities that have been implicated as contributors to stasis and stone formation include sliding inguinal hernias containing the urinary bladder.9
Multiple underlying risk factors predispose to bladder stones in pediatric patients who undergo bladder augmentation. Mathoera et al (2000) described risk factors for stone formation in 89 pediatric patients who had undergone bladder augmentation and presented with bladder calculi. Cloacal malformations, vaginal reconstructions, ureteral reimplantations, and bladder neck surgery were all associated with higher risk for stone formation. Preventive antibiotic therapy for recurrent infections decreased the amount of struvite stone formation but yielded no statistically significant reduction in overall stone formation.10
Other etiologic factors for bladder stone formation include foreign bodies in the bladder that act as a nidus for stone formation. These are subclassified into iatrogenic and noniatrogenic bodies. The first group includes suture material, shattered Foley catheter balloons, eggshell calcifications that form on a catheter balloon, staples, ureteral stents, migrating contraceptive devices, erosions of surgical implants, and prostatic urethral stents.11,12,13,14,15 Stones on suture material may have an early presentation if sutures were originally placed within the bladder lumen or may have a delayed presentation if they are caused by erosion through the bladder wall.16 Noniatrogenic causes include objects placed into the bladder by the patients for recreational and various other reasons.17
Metabolic abnormalities are not a significant cause of stone formation in patients with urinary diversions. In this group of patients, the stones are primarily composed of calcium and struvite. In rare cases, medications (eg, viral protease inhibitors) may be the source for bladder calculus formation.18
In general, if an otherwise healthy person in the United States or Europe is found to have a bladder stone, a complete urological evaluation must be undertaken to find a cause for urinary stasis. Examples include benign prostatic hyperplasia, urethral stricture, neurogenic bladder, diverticula, and congenital anomalies such as ureterocele and bladder neck contracture. In females, examples include an incontinence repair that is too tight, cystoceles, and bladder diverticula.19
Pathophysiology
Most vesical calculi are formed de novo within the bladder, but some may initially have formed within the kidneys as a dissociated Randall plaque or on a sloughed papilla and subsequently passed into the bladder, where additional deposition of crystals cause the stone to grow. However, most renal stones that are small enough to pass through the ureters are also small enough to pass through a normally functioning bladder and unobstructed urethra. In older men with bladder stones composed of uric acid, the stone most likely formed in the bladder. Stones composed of calcium oxalate are usually initially formed in the kidney.
The most common type of vesical stone in adults is composed of uric acid (>50%). Less frequently, bladder calculi are composed of calcium oxalate, calcium phosphate, ammonium urate, cysteine, or magnesium ammonium phosphate (when associated with infection).20,21 Interestingly, patients with uric acid bladder calculi rarely ever have a documented history of gout or hyperuricemia. In many cases, the core is composed of one chemical, while layers of different chemicals form around it.
Pediatric stones are composed mainly of ammonium acid urate, calcium oxalate, or an impure mixture of ammonium acid urate and calcium oxalate with calcium phosphate.22 The common link among endemic areas relates to feeding infants human breast milk and polished rice. These foods are low in phosphorus, ultimately leading to high ammonia excretion. These children also usually have a high intake of oxalate-rich vegetables (increased oxalate crystalluria) and animal protein (low dietary citrate).23,7,22 Bladder stones in patients with spinal cord injuries are often composed of struvite or calcium phosphate.
Vesical calculi may be single or multiple, especially in the presence of bladder diverticula. Vesical calculi can be small or large enough to occupy the entire bladder. Their physical features range from soft to extremely hard and from having smooth-faceted surfaces to jagged spiculated surfaces, the latter termed "jack" stones based on their resemblance to the metal objects in the children's game Jacks (see image below). In general, most vesical calculi are mobile within the bladder, although some stones are fixed when they form on a suture, on the intravesical portion of a papillary tumor, or on retained stents.
Two delicate jack stones removed prior to open pr...
Two delicate jack stones removed prior to open prostatectomy.
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Two delicate jack stones removed prior to open pr...
Two delicate jack stones removed prior to open prostatectomy.
In regions where vesical lithiasis is endemic among children, stone formation is more common among boys younger than 11 years, more common among people from low socioeconomic backgrounds, not usually associated with renal calculi, and relatively less likely to reoccur after treatment (when compared with upper tract calculi).24
Presentation
The presentation of vesical calculi varies from completely asymptomatic to symptoms of suprapubic pain, dysuria, intermittency, frequency, hesitancy, nocturia, and urinary retention.21 Parents of children with vesical calculi may notice priapism and occasional enuresis.8
Other common signs include terminal gross hematuria and sudden termination of voiding with some degree of associated pain referred to the tip of the penis, scrotum, perineum, back, or hip. The discomfort may be dull or sharp and is often aggravated by sudden movements and exercise. Assuming a supine, prone, or lateral head-down position may alleviate the pain initiated by the stone impacting the bladder neck by causing it to roll back into the bladder. Less specific signs of vesical calculi include microscopic or gross hematuria, pyuria, bacteriuria, crystalluria, and urine cultures that demonstrate urea-splitting organisms.
A history of prior pelvic surgery should be sought in all patients, especially when synthetic materials were implanted.25
Common physical examination findings include suprapubic tenderness, fullness, and, occasionally, a palpable distended bladder if the patient is in acute urinary retention. Associated findings include cystoceles in women, stomal stenosis (if the patient had undergone prior urinary diversion), and neurological deficits in patients with neurogenic bladder.
Historically, bladder calculi were diagnosed based on transurethral passage of van Buren sounds. The contact of the van Buren sounds with the stones causes transmission of a clicking noise or vibration, which confirms the presence of the stone. Because of advancements in cystoscopy, this maneuver is rarely used today. Currently, abdominopelvic planar radiography is used to easily identify radio-opaque stones. However, adult calculi, which are composed predominantly of uric acid, are radiolucent and, unless coated with calcium, are more difficult to visualize on radiographs. Cystoscopy, noncontrast CT scanning, and ultrasonography are common diagnostic methods used to confirm the presence of bladder calculi.8
Indications
Because a bladder stone is in itself a sign of an underlying problem, removal of the stone and treatment of the underlying abnormality are nearly always indicated. Management of the underlying cause of stone formation (eg, bladder outlet obstruction, infections, foreign body, diet) has been integral to preventing recurrence. Recent literature describes treatment of bladder calculi without relieving outlet obstruction, but the follow-up period was not long enough to warrant this as general practice.26
Relevant Anatomy
In men, the main anatomical problem that leads to vesical obstruction is prostatic enlargement. The prostate forms a ringlike growth around the vesical neck and, when hypertrophic, can significantly impede the flow of urine. Stasis due to this blockage is responsible for the deposition of layer upon layer of new stone material.
In women, voiding dysfunction and urinary stasis can occur but are less commonly associated with calculi. Typical anatomic findings include cystoceles, enteroceles, or findings of prior urethral surgery, all of which contribute to elevated residuals. With rare exceptions, any foreign body that cannot escape the bladder is calcified and eventually forms a stone.
Contraindications
The only contraindication to bladder stone removal would be existence of the stone in a medically unstable or near-terminal asymptomatic patient.
In general, most vesical calculi procedures are performed via endoscopy. However, when the stone is too large or too hard or if the patient's urethra is too small (eg, in children) or surgically altered, complicating access to the bladder, the open or percutaneous suprapubic surgical approach is preferable.
Relative contraindications exist to certain types of bladder stone ablative techniques. Electrohydraulic lithotripsy (EHL) should be used with great caution in patients with small-capacity bladders and those with cardiac-pacing or defibrillation devices. Percutaneous lithotripsy may be more hazardous in patients who have undergone prior lower abdominal surgery or prior pelvic surgery or who have small-capacity noncompliant bladders.
Pregnancy is a relative contraindication to some forms of lithotripsy (eg, extracorporeal shock-wave lithotripsy [ESWL], EHL, mechanical lithotrity), but the benefits of eliminating a source of infection, retention, or pain with other modalities (eg, holmium laser, lithoclast), as well as a potential complicator of vaginal delivery if stones are large, may outweigh the risk of intervention.27
Otherwise, the usual contraindications to any type of surgery also apply here.Workup
Laboratory Studies
* Urinalysis: Urinalysis is usually inexpensive, rapid and provides useful information in this setting. On the dipstick, bladder calculi can be associated with test results that are positive for nitrite, leukocyte esterase, and blood. Since bladder calculi usually cause dysuria and pain, most patients reduce their daily fluid intake and raise their urine specific gravity. Adults with uric acid bladder calculi are expected to have an acidic pH. Microscopy usually demonstrates red blood cells (RBCs) and pyuria (WBCs). Microscopic crystals are usually consistent with the composition of the stone.
* Urine culture and sensitivity: A culture of the urine is integral to help document and direct treatment of associated infections.
* CBC count: In patients with outlet obstruction and infection, the white blood cell (WBC) count may be elevated, with a left shift.
* Comprehensive metabolic panel: The creatinine level may be elevated in outlet obstruction. Other findings may give a clue to an underlying abnormality.
Imaging Studies
Urography of the kidneys, ureters, and bladder
The initial imaging study of choice is plain radiography of the kidneys, ureters, and bladder (KUB) because it is the least expensive and easiest radiologic test to obtain. Alone or as the first film of an intravenous pyelogram (IVP), KUB demonstrates the presence of radio-opaque stones. Pure uric acid and ammonium urate stones are radiolucent but are occasionally coated with a layer of opaque calcium sediment. Laminations are common, with the layers stratified according to metabolic and infectious status and the degree of periodic hematuria (see image below).8
Multiple laminated bladder calculi in a patient w...
Multiple laminated bladder calculi in a patient with a neurogenic bladder.
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Multiple laminated bladder calculi in a patient w...
Multiple laminated bladder calculi in a patient with a neurogenic bladder.
Cystography and intravenous pyelography
If the clinical suspicion remains high and the initial KUB reveals no stones, the next step is cystography or IVP. These tests demonstrate the stone as a filling defect in the bladder. If the filling defect moves when the patient is repositioned, the presence of a stone is highly likely (differential diagnoses include clot, fungal ball, and papillary urothelial carcinoma on a stalk). Nonmobile filling defects could be calculi attached to the bladder wall via a stitch or in a diverticulum (differential diagnoses include urothelial carcinoma, clot, and calculus). IVP may also be used to identify associated abnormalities such as upper-tract calculi, ureterocele, cystocele, enlarged prostate, and bladder diverticula.8
Ultrasonography
With the recent widespread availability of ultrasonography, this relatively inexpensive and rapid modality can be more widely used to diagnose bladder calculi. The sonogram, showing a classic hyperechoic object with posterior shadowing, is effective in identifying both radiolucent and radio-opaque stones.28
Computed tomography scan
CT scan is usually obtained for other reasons (eg, abdominal pain, pelvic mass, suspected abscess) but may demonstrate bladder calculi when performed without intravenous contrast. Unenhanced spiral CT scan is highly sensitive and specific in diagnosing calculi along the urinary tract. Even pure urate calculi can be detected with this method. The stone may be obscured if contrast has been administered.8
Pelvic magnetic resonance imaging
MRI is an expensive imaging modality that yields poor resolution of calculi. It is not recommended in the evaluation of bladder calculi. If performed, MRI may show an incidental black hole of low water content corresponding to a calculus in an otherwise full bladder.
Tc-99m MAG-3 renal scanning
As with MRI, Tc-99m MAG-3 renal scanning is a poor imaging modality in this condition. It may demonstrate the incidental finding of focal photopenia within the bladder resulting from calculus formation.29
Diagnostic Procedures
Cystoscopy remains the most commonly used test to confirm the presence of bladder stones and plan treatment. This procedure allows for the visualization of stones and assessment of their number, size, and position. Additionally, examination of the urethra, prostate, bladder wall, and ureteral orifices allows identification of strictures, prostatic obstruction, bladder diverticula, and bladder tumors.8 See an endoscopic view in the image below.
Endoscopic view of a spiculated jack stone with e...
Endoscopic view of a spiculated jack stone with erythematous bladder mucosa in the background.
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Endoscopic view of a spiculated jack stone with e...
Endoscopic view of a spiculated jack stone with erythematous bladder mucosa in the background.
Histologic Findings
The presence of long-standing untreated bladder calculi is associated with dysplasia and squamous cell carcinoma of the bladder. Occasionally, a calculus is found adherent to a transitional cell carcinoma. If a suspicious area does not clear after successful removal of the calculus and treatment of any associated infection, biopsy is performed to rule out malignant degeneration.Treatment
Medical Therapy
The only potentially effective medical treatment for bladder calculi is urinary alkalinization for the dissolution of uric acid stones. Stone dissolution may be possible if the urinary pH can be made greater than or equal to 6.5. Potassium citrate (Polycitra K, Urocit K) at 60 mEq/d is the treatment of choice. However, overly aggressive alkalization may lead to calcium phosphate deposits on the stone surface, making further medical therapy ineffective.8
Other agents for stone dissolution, such as Suby G or M solution, are rarely used. Renacidin can be used to dissolve phosphate or struvite calculi, but treatment is slow and invasive because it must be used in conjunction with indwelling irrigating catheters. Patients must also be monitored closely for signs of sepsis or hypermagnesemia. Further measures include irrigations of the bladder or continent diversions with saline for a mechanical flushing of debris or with one of the above solutions for preventing stone formation.6
When underlying errors of metabolism are discovered during 24-hour urine evaluation of stone disease, various treatments are available to prevent further calculus development. However, the discussion of these treatments is beyond the scope of this article.
Surgical Therapy
"Cutting for the stone" is a phrase that has been used since the time of Hippocrates. Historically, stones were removed via the high operation, using a suprapubic incision, or the low operation, using a perineal incision. In the absence of antibiotic therapy and adequate hemostatic techniques, both operations were associated with a high morbidity and mortality rate. Civiale performed the first documented blind transurethral lithotripsy in 1822. Even with the introduction of the cystoscope in 1877, bladder injury was always a risk. The predominant technique in the 1800s and early 1900s was to fill the bladder with 150 mL of fluid, grasp the stone with the lithotrite, rotate it to free the engaged stone from the mucosa, and crush the stone manually. This was repeated until the fragments were small enough to suction out of the bladder with an Ellik evacuator. Common complications included mucosal injury, bladder wall perforation, sepsis, and hemorrhage.1
Currently, 3 different surgical approaches to this problem are used. Unlike in renal and most ureteral calculi, ESWL has shown little efficacy for bladder calculi in most centers,30 but some studies suggest that ESWL performed with the patient in the prone position can be considered for treatment.5
The first approach in adults is transurethral cystolitholapaxy. After cystoscopy is performed to visualize the stone, an energy source is used to fragment it, and the fragments are removed through the cystoscope. The energy sources are mechanical (ie, lithoclast [pneumatic jack hammer]), ultrasonic, electrohydraulic (ie, EHL [spark-induced pressure wave]), manual lithotrite, and laser. The pulsed-dye or other wavelength-specific light sources (eg, holmium) fracture the stone by direct absorption, vaporization, water absorption, and pressure wave generation.31 Because of recent advancements in instrumentation, the smaller caliber of the pediatric urethra can be accommodated, allowing these approaches to be applicable in selected children.32
The second approach in adults (and often primary approach in the pediatric population) is percutaneous suprapubic cystolitholapaxy. The percutaneous route allows the use of shorter- and larger-diameter endoscopic equipment (usually with an ultrasonic lithotripter), which allows rapid fragmentation and evacuation of the calculi.33 Often, a combined transurethral and percutaneous approach can be used to aid in stone stabilization and to facilitate irrigation of the stone debris. The authors favor the combined approach with the use of the ultrasonic lithotripter or the pneumatic lithoclast. The holmium laser is also effective but is generally slower, even with the 1000-micron fiber.34
The EHL unit has been associated with a higher incidence of bladder mucosal injury. Options for accessing the bladder may be challenging in certain circumstances, such as in patients who have undergone prior bladder reconstruction or after prior bladder neck procedures for improved continence. Paez et al (2007) described percutaneous removal of bladder stones via ultrasound-assisted access of the bladder through prior suprapubic tube tracts. In one case, they used a Mitrofanoff catheterization channel with a 30F Amplatz sheath. They reported no complications, and percutaneous treatment was judged a safe alternative in this population subset.35 This same procedure has also been described in continent diversions with urethral closure.36
First described in 1963 by Barnes et al and supported by numerous subsequent articles, transurethral lithotripsy combined with transurethral resection of the prostate (TURP) or transurethral incision of the prostate (TUIP) can be accomplished easily and safely.37,38 Completing the stone ablation prior to these prostatic interventions is advisable, as hemorrhage and excess fluid absorption are potential complications when performed in the reverse order.
In a 2009 study by Tugcu et al, 64 patients underwent TURP in addition to concomitant bladder calculi surgery. The participants were divided and treated with either (1) a percutaneous suprapubic approach with a 30F access sheath or (2) transurethral cystolitholapaxy with a 23F sheath and pneumatic lithotripter. The patients who underwent percutaneous stone removal had a statistically significantly larger stone burden, and the mean operative time of the percutaneous approach was nearly half that of the transurethral removal.39
The third approach, open suprapubic cystotomy, is used to remove the stone or stones intact and can be used with larger and harder stones and when open prostatectomy and/or bladder diverticulectomy are indicated. Open prostatectomy is generally indicated when the prostate volume exceeds 80-100 g. The advantages of suprapubic cystolithotomy include rapidity, easy removal of several calculi at one time, removal of calculi that are adherent to bladder mucosa, and the ability to remove large stones that are too hard or dense to fragment expeditiously via transurethral or percutaneous techniques. The major disadvantages include postoperative pain, longer hospital stay, and longer bladder catheterization times.
Preoperative Details
After diagnosis and treatment planning have been completed, the usual preoperative evaluation, including urine culture and sensitivity, CBC count, comprehensive metabolic panel (ie, serum chemistries), coagulation studies, chest radiography, and ECG, is completed. When a sterile urine culture is not attainable preoperatively, appropriate antibiotic therapy should be started a minimum of 24 hours in advance of the anticipated procedure.
* Anesthesia: Regional or general anesthesia can be used depending on the patient's comorbidities and the anesthesiologist's preference. Performance under local anesthesia (eg, urethral and intravesical lidocaine, tetracaine, dicyclomine) can be accomplished in certain patients harboring a low stone burden. The procedure requires pain tolerance similar to that for rigid cystoscopy with a 17F sheath.40
* Positioning: The preferred position is the dorsal lithotomy, although supine positioning also can work well if flexible cystoscopes and/or percutaneous access are used.
* Antibiotics: Appropriate oral or intravenous antibiotics are administered prior to the start of the operation based on the findings of the preoperative urine culture and sensitivity. When the urine culture is sterile, an oral fluoroquinolone generally provides adequate prophylaxis.
* Preparation: The lower abdomen and perineum are shaved, prepared using Betadine or another antiseptic solution, and draped in the usual sterile fashion. The irrigant of choice is isotonic sodium chloride solution, although sterile water or sorbitol can be substituted for short procedures. Significant absorption of a hypotonic solution may be a problem if bleeding is encountered.
Intraoperative Details
The most commonly used contemporary treatment for bladder calculi is transurethral cystolitholapaxy. This can be performed using rigid or flexible cystoscopes; larger-caliber, rigid, continuous-flow scopes provide better visualization.
Procedural details
A cystoscope with a camera to provide video imaging is used to identify the stone under direct vision. If previous gross hematuria was noted, careful removal of all clots is necessary to ensure identification of all stone material. The bladder mucosa and bladder neck must also be fully assessed. Lithotripsy is performed, and the small remnant fragments are removed with one of several commercially available evacuators. Once inspection reveals no residual fragments in the bladder or any diverticula, attention can be paid to the bladder outlet or diverticula for further management of obstruction.
For TUIP and TURP, the irrigant is changed to 3% sorbitol, and the operation is completed in the usual fashion. If percutaneous access to the bladder has been established, the access sheath or a large-bore catheter can be left in place to assist with continuous irrigation during TURP. If the bladder is not obstructed but a diverticulum needs to be addressed, sterile water or sorbitol can be used for diverticular fulguration and incision of the diverticular neck. While generally safe if performed expeditiously, reports have indicated that combined operations are associated with significantly increased complication rates (ie, 20%-30%). A catheter is generally left in place overnight if TURP or TUIP has been performed. Incision of a diverticular neck may require that a catheter be left for a few days to protect against urinary extravasation.
Lithotripsy instrumentation
Energy sources used to fragment the stone vary. A commonly used type of energy source is EHL. Other sources include the pulse-dye laser, the holmium laser, ultrasound, and the lithoclast (pneumatic jackhammer).41 The EHL probe was first introduced in 1959; since then, it has been widely used with excellent results. The EHL probe (5F-9F) can be inserted through the working port of the cystoscope and advanced 1 cm beyond the lens. The probe must remain at least 1 cm away from the bladder mucosa to prevent injury and perforation of the bladder. The probe is then positioned 1-2 mm away from the stone, and fragmentation is initiated under direct vision to avoid bladder injury.
Pinning the stone against the bladder wall may reduce the duration of the procedure, but take care not to involve the ureteral orifices. Fragmentation of the stone is initiated by cracking the outer layers until the stone is reduced to a size suitable for evacuation. A manual suction evacuator (eg, Microvasive, Ellik) is commonly used to remove the fragments, although grasping forceps can also be used. Frequent drainage of the bladder or low-pressure continuous irrigation during the procedure is important to prevent bladder rupture. The success rate of EHL is 92%-100% for stone sizes of 3-6 cm. Relative contraindications to EHL include small-capacity bladder, possibly pregnancy, and the presence of a cardiac-pacing or defibrillation devices.
The lithoclast and laser (holmium) lithotripters are used for calculi in all locations throughout the urinary tract, and they have largely supplanted the EHL unit when available. Ultrasonic lithotripsy is also commonly used for renal and bladder calculi.8
Special situations
Percutaneous lithotripsy has become the treatment of choice in the pediatric population because it prevents potential injury to the small-caliber urethra while providing an approach that is less invasive than open surgery, thus reducing pain and hospital stay. Access is obtained in a fashion similar to renal access. A rigid nephroscope, graspers, the ultrasonic lithotripter, and suction are used for rapid stone fragmentation and evacuation. Contraindications include prior lower abdominal surgery, prior pelvic surgery, and small-capacity noncompliant bladders.42,43,44
A report by Isen et al (2008) studied the use of a semirigid ureteroscope with holmium laser lithotripsy for bladder stones in 27 boys aged 3-14 years. At 2 weeks postsurgery, all patients were stone-free, and only two had required repeat intervention owing to obstruction by stone fragments. This treatment was recommended as an alternative approach to bladder stones in children with stones smaller than 2 cm.45
Postoperative Details
The usual postoperative course includes a short duration of catheterization, until the effects of anesthesia abate. The antibiotic coverage is continued according to preoperative findings and discontinued after the appropriate length of treatment, usually 5-7 days for an active preoperative infection or until the drains and catheters are removed. Hospitalization is unnecessary unless secondary procedures have been performed or the open surgical approach was used. Anticoagulants should be avoided until any hematuria has resolved.
Follow-up
Typical follow-up is 3-4 weeks postoperatively with KUB or bladder ultrasonography to document clearing of all the fragments. Thereafter, metabolic evaluation may be pursued as indicated and periodic KUB at approximately 6- to 12-month intervals is warranted. A metabolic stone profile analysis is indicated in patients with uric acid stones, concurrent upper tract calculi, a strong family history of stone disease, calculi without obstruction, and recurrent calculi.
Complications
Transurethral litholapaxy is, by far, the most common general modality used to treat bladder calculi and has been associated with relatively few minor complications. Common complications include urinary infection (11%), fever (9%), bladder perforation (2%), hyponatremia (2%), and hemorrhage (1%). Fever and urinary tract infection are clinical diagnoses marked by fever, dysuria, elevated WBC count, and positive findings on urinalysis and cultures. Treatment involves intravenous antibiotics and good bladder drainage. Gross hematuria is not uncommon and, when present, usually self-limiting. In severe cases, 3-way catheter irrigation and blood transfusions may be necessary. Bladder perforation is usually diagnosed intraoperatively when irrigating solution suddenly does not return during the procedure. Intraoperative cystography is used to confirm the diagnosis.
Extraperitoneal perforation is managed with a Foley catheter, while intraperitoneal perforation usually requires retrieval of extravasated stone debris, open surgical repair of the bladder wall, and placement of a Foley catheter. The catheter is left for 5-7 days, and, prior to removal of the catheter, cystography may be performed to rule out leakage.
Hyponatremia can be a consequence of cystolitholapaxy in combination with TURP. Low serum sodium levels with mental status changes and lethargy confirm the diagnosis. The treatment involves termination of the procedure and administration of intravenous furosemide, isotonic sodium chloride solution or other iso-osmotic intravenous fluids postoperatively, and, occasionally, short-term use of 3% hypertonic sodium chloride solution if the patient is acutely symptomatic and not otherwise responding. Symptoms generally develop as the serum sodium level falls below 125 mg/dLFuture and Controversies
The incidence of bladder stones in children is slowly declining, even in endemic areas. This is mostly due to improved nutrition, better prenatal and postnatal care, and improved awareness of the problem in the endemic areas. In the 21st century, the incidence of this disease in children will probably continue to decline and the disease will largely become a disease of adults.
The aggressive treatment of lower urinary tract symptoms with alpha-blockers and 5-alpha-reductase inhibitors should further decrease the overall incidence of bladder stones because of improved bladder emptying. The removal of bladder stones will continue to progress toward minimally invasive techniques, thus decreasing hospital stay and recovery times. Continued advancement of surgical equipment and the ability to downsize, without the sacrifice of effectiveness, could eventually make open surgery for stones obsolete. Additionally, continued aggressive management of neurogenic bladder, specifically in the pediatric neurogenic bladder population, may lead to a rise in both the incidence of struvite stones as well as the development of creative and minimally invasive surgical techniques in augmented bladders.
