Approach Considerations
Because a bladder stone is in itself a sign of an underlying problem, both 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, or diet) is integral to prevention of recurrence. 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, if the stone is too large or too hard or if the patient’s urethra is too small (eg, in children) or has been surgically altered in such a way as to complicate access to the bladder, an open or percutaneous suprapubic surgical approach is preferable. The presence of bladder calculi in patients with benign prostatic hyperplasia (BPH) is an absolute indication for surgery. [30]
Pharmacologic Stone Dissolution
The only potentially effective medical treatment for bladder calculi is urinary alkalization for the dissolution of uric acid stones. Stone dissolution may be possible if the urinary pH can be raised to 6.5 or higher. Potassium citrate 60 mEq/day is the treatment of choice. However, overly aggressive alkalization may lead to calcium phosphate deposits on the stone surface, making further medical therapy ineffective. [10]
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 irrigation of the bladder or continent diversions with saline for mechanical flushing of debris or with one of the above solutions for prevention of stone formation. [25]
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, discussion of these treatments is beyond the scope of this article.
Surgical Fragmentation and Removal
Currently, 3 different surgical approaches to this problem are used:
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Transurethral cystolitholapaxy
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Percutaneous suprapubic cystolitholapaxy
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Open suprapubic cystotomy
A systematic review and meta-analysis concluded that a transurethral approach, when feasible, is the intervention of choice for bladder stones in adults and children, because of shorter procedure duration and hospital stay. The evidence suggested that endoscopic surgery is as effective as open surgery. [31]
Transurethral cystolitholapaxy
In transurethral cystolitholapaxy, cystoscopy is performed to visualize the stone, an energy source is used to fragment it, and the fragments are then removed through the cystoscope. The energy sources may be a mechanical device (ie, a lithoclast [pneumatic jack hammer]), an ultrasonic device, an electrohydraulic device, a manual lithotrite, or a laser.
Unlike renal and most ureteral calculi, bladder calculi have not been effectively treated with electrohydraulic shock-wave lithotripsy (ESWL) in most centers [32] ; however, some studies suggest that ESWL performed with the patient in the prone position can be considered. [33] The pulsed-dye and other wavelength-specific light sources (eg, holmium laser) fracture the stone through direct absorption, vaporization, water absorption, and pressure-wave generation. [34] A case report describes successful transurethral cystolitholapaxy of a 4-cm bladder stone with the EMS LithoClast Trilogy lithotripter (EMS Electro Medical Systems SA, Amherst, MA), a device that combines an electromagnetic impactor with ultrasonic energy and suction in a single probe. [35]
Because of ongoing advances in instrumentation, the smaller caliber of the pediatric urethra can be accommodated. Thus, these approaches are now applicable to selected children. [36]
Percutaneous suprapubic cystolitholapaxy
In percutaneous suprapubic cystolitholapaxy (which now is often the primary approach in the pediatric population), the percutaneous route allows the use of shorter- and larger-diameter endoscopic equipment (usually with an ultrasonic lithotripter), thereby permitting rapid fragmentation and evacuation of calculi. [37]
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 a 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-µm fiber. [38]
The electrohydraulic lithotripsy (EHL) unit has been associated with a higher incidence of bladder mucosal injury. [39] Options for accessing the bladder may be challenging in certain circumstances, such as in patients who have undergone prior bladder reconstruction or prior bladder neck procedures for improved continence.
Paez et al, in a study of percutaneous removal of bladder stones via ultrasound-assisted access of the bladder through prior suprapubic tube tracts (a Mitrofanoff catheterization channel with a 30-French Amplatz sheath was used in 1 case) reported no complications and concluded that percutaneous treatment was a safe alternative in this population subset. [40] This same procedure has also been described in continent diversions with urethral closure. [41]
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. [42, 43] It is advisable to complete the stone ablation before carrying out these prostatic interventions; hemorrhage and excess fluid absorption are potential complications when the procedures are performed in the reverse order.
In a study by Tugcu et al, 64 patients underwent TURP in addition to concomitant bladder calculi surgery. [44] Participants were treated with either (1) a percutaneous suprapubic approach with a 30-French access sheath or (2) transurethral cystolitholapaxy with a 23-French sheath and pneumatic lithotripter; those who underwent percutaneous stone removal had a statistically significantly larger stone burden, and the mean operating time for the percutaneous approach was nearly half that for transurethral removal.
A case report by Wilhelm and colleagues describes successful treatment of a patient who had undergone lower urinary tract reconstruction, with creation of an ileal pouch and a continent umbilical stoma, and had developed pouch urolithiasis in the urinary reservoir. The stone was extracted through the stoma via a modified access sheath, using flexible ureteroscopy and laser lithotripsy. No analgesia was needed, and the procedure was performed in an outpatient setting. [45]
Open suprapubic cystotomy
In open suprapubic cystotomy, stones are not fragmented but are removed intact. This approach can be used with larger and harder stones and in cases where open prostatectomy or bladder diverticulectomy is 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 in a single procedure, the ability to extract 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.
Long-Term Monitoring
Typical follow-up is 3-4 weeks postoperatively with kidney-ureter-bladder (KUB) radiography or bladder ultrasonography to document clearing of all the fragments. Thereafter, metabolic evaluation may be pursued as indicated, and KUB radiography may be done at 6- to 12-month intervals as 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.
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Multiple laminated bladder calculi in patient with neurogenic bladder.
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Endoscopic view of spiculated "jack" stone with erythematous bladder mucosa in background.
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Large calculus visible on plain film of intravenous pyelogram performed for hematuria.
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Ex vivo photograph of bladder stone.
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Two delicate "jack" stones removed before open prostatectomy.
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Bladder stone accretion on matrix. Patient had history of urinary tract infections and presented with irritative voiding symptoms and microscopic hematuria. Upper-tract evaluation findings were normal, but cystoscopy demonstrated calculus. Upon laser treatment of stone, soft matrix core was encountered beneath glistening outer core. Exposed matrix core is visible in crevices.
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Bladder stone accretion on matrix. Patient had history of urinary tract infections and presented with irritative voiding symptoms and microscopic hematuria. Upper-tract evaluation findings were normal, but cystoscopy demonstrated calculus. Upon laser treatment of stone, soft matrix core was encountered beneath glistening outer core. Exposed matrix core is visible in crevices.
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Laser destruction of stone. Note small lacuna generated in stone as result of laser energy. At lower power settings, stone can be quickly reduced to dust.
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Layered nature of bladder calculus exposed as laser strips away surface.
