Marshall L. Stoller, Maxwell V. Meng-Urinary Stone Disease

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Chapter 34 / Laparoscopic Approach 659

with complete “stone” removal in 70% of animals. Nuclear renal scans documented an

improvement in glomerular filtration rate after relief of obstruction and stone removal.

To date, the clinical experience in humans remains limited (14).

CONCLUSION

The laparoscopic approach to renal and ureteral calculi represents an effective and

minimally invasive modality to manage these calculi. It allows for correction of any

underlying anatomical abnormality thus reducing risk for recurrent stone formation.

Appropriate patient selection is however of paramount importance. With experience,

laparoscopy can be applied to the management of most renal and ureteral calculi, which

fail or are unsuitable for endourologic and shockwave management. As more centers

overcome the learning curve, laparoscopy will be widely available for managing appro-

priate renal calculi in the near future.

REFERENCES

1. Begun FP, Foley WD, Peterson A, White B. Patient evaluation: Laboratory and imaging studies.

Urol Clin North Am 1997; 1: 97–115.

2. Gaur DD, Agarwal DK, Purohit KC, Darshane AS. Retroperitoneal laparoscopic pyelolithotomy.

J Urol 1994; 151: 927.

3. Jordan GH, McCammon KA, Robey EL. Laparoscopic pyelolithotomy. Urology 1994; 49: 131–134.

4. Ramakumar S, Lancini V, Chan DY, Parsons JK, Kavoussi LR, Jarrett TW. Laparoscopic

pyeloplasty with concomitant pyelolithotomy. J Urol 2002; 167: 1378–1380.

5. Harewood LM, Pope AJ. Laparoscopic ureterolithotomy: the results of an initial series, and evalu-

ation of it’s role in the management of ureteric calculi. Br J Urol 1994; 74: 170–176.

6. Feyaerts A, Rietbergen J, Navarra S, Vallancien G, Guillonneau B. Laparoscopic ureterolithotomy

for ureteral calculi. J Urol 2001; 40: 609–613.

7. Wickham JEA. The surgery of renal lithiasis. In: Urinary Calculus Disease. Churchill Livingstone,

Edinburgh, 1979: 145–198.

8. Raboy A, Ferzli GS, Ioffreda R, Albert PS. Laparoscopic ureterolithotomy. Urology 1992; 39:

223–225.

9. Miller SD, Ng CS, Streem SB, Gill IS. Laparoscopic management of caliceal diverticular calculi.

J Urol 2002; 167: 1248–1252.

10. Gill IS, Cherullo EE, Steinberg AP, Desai MM, Abreu SC, Ng C, Kaouk JH. Laparoscopic

ureterocalicostomy: initial experience. J Urol 2004; 171: 1227–1230.

11. Assimos DG. Anatrophic nephrolithotomy. Urology 2001; 57: 161–165.

12. Kaouk JH, Gill IS, Desai MM, et al. Laparoscopic anatrophic nephrolithotomy. J Urol 2003; 169:

691–696.

13. Kaouk JH, Banks KL, Desai MM, et al. Laparoscopic anatrophic nephrolithotomy. J Urol 2001;

165(2): 376, abstract 1542.

14. Deger S, Tuellmann M, Schoenberger B, et al. Laparoscopic anatrophic nephrolithotomy. Scand

J Urol Nephrol 2004; 38: 263.

Chapter 35 / The “Other” Stones 661

661

From: Current Clinical Urology, Urinary Stone Disease:

A Practical Guide to Medical and Surgical Management

Edited by: M. L. Stoller and M. V. Meng © Humana Press Inc., Totowa, NJ

Stones of the Urethra, Prostate,

Seminal Vesicle, Bladder,

and Encrusted Foreign Bodies

Bradley F. Schwartz, DO, FACS

CONTENTS

INTRODUCTION

URETHRAL CALCULI

PROSTATIC CALCULI

SEMINAL VESICLE CALCULI

BLADDER CALCULI

ENCRUSTED FOREIGN BODIES

REFERENCES

Key Words: Calculus; bladder stone; encrustation; foreign body.

INTRODUCTION

Renal and ureteral calculi comprise the majority of genitourinary calcifications

encountered clinically. Significant morbidity, however, may occur from less common

urologic calculi. Although treatment of most stones remains uncomplicated, etiology

and prevention prove elusive. Mandel hypothesized that most if not all extraosseous

calcifications in the body arise from a nidus of carbonate apatite (1). If this is true,

inhibition of the initial crystallization may help prevent formation of most genitourinary

stones. Hopefully, future research and investigation will help us understand and even-

tually direct nonsurgical treatment of these calculi. This chapter discusses the etiology,

symptoms, diagnosis, treatment, and prevention of stones found in the urethra, prostate,

seminal vesicle, and bladder. The management and prevention of encrusted foreign

bodies is also presented.

662 Schwartz

URETHRAL CALCULI

Etiology

Most urethral calculi originate in the kidney or urinary bladder (2–4). A review of 271

urethral calculi demonstrates a clear male predominance (253 to 18) with the majority

occurring in the posterior urethra (2–15). Koga (2) treated 56 patients with urethral

calculi and found a 32% incidence of simultaneous renal and ureteral calculi. A similar

study from the Sudan reported 33% of their 36 patients suffered from upper tract calculi

(15), both studies emphasizing the importance of upper urinary tract evaluation in

patients with urethral calculi. The normal diameter of the adult human urethra of 30 Fr

should allow stones 10 mm to pass spontaneously, but stone configuration, previous

surgery, or radiation therapy, and anatomical abnormalities such as diverticulae and

strictures may prevent such passage.

Stones that do not originate in the urethra are usually composed of calcium. Paulk (3)

reported on 47 patients referred to the Mayo Clinic with urethral stones, 21 of whom had

stone analysis performed. Twenty of 21 (95%) were calcium based and one was struvite.

In contrast, a study from Turkey published the authors’ results on 60 children with

urethral stones (5). Stone analysis was available on only 12 patients, and all of them were

struvite. Those studies reporting urine culture results found that 68% of isolates were

urease-splitting organisms (3,7). Calcium oxalate, calcium phosphate, and uric acid

urethral stones have been associated with the use of the hypercholesterolemia agent

cholestyramine (6). In general, stones found in Western societies that originate in the

upper urinary tract are noninfectious, calcium-based calculi, and those encountered in

non-Western cultures developing in abnormal urinary tracts are usually ammonium acid

urate or struvite.

The pediatric patient often presents a different set of etiological circumstances. Hypo-

spadias, cloacal and bladder exstrophy, bladder neck reconstruction procedures, and

posterior urethral valves predispose this population to urethral calculi formation (5,7–

9). A detailed history should be sought in these patients.

Symptoms

Patients with urethral calculi may present with a wide range of symptoms (Table 1).

Virtually all patients with urethral calculi have pain with or without lower urinary tract

symptoms (LUTS). Urinary retention, especially in children, is a common presentation,

and urethral calculi should be suspected when a history of lower urinary tract surgery is

elicited. A palpable mass along the course of the urethra warrants a high index of sus-

picion, as does a perineal cutaneous fistula, and should prompt either radiographic or

cystoscopic evaluation.

Diagnosis

A thorough history should be obtained and a genitourinary physical examination

should be performed. Because most primary urethral stones form in an abnormal ure-

thra, either from obstruction or stasis, information regarding previous surgery or the

presence of lower urinary tract symptoms such as urinary urgency, intermittency, dys-

uria, decreased force of stream, or incontinence should be sought. Although some ure-

thral calculi are diagnosed serendipitously by radiographic studies, the single best

diagnostic modality remains urethroscopy. Endoscopic evaluation of the lower urinary

Chapter 35 / The “Other” Stones 663

tract will also enable the urologist to identify other comorbid conditions that may impact

the treatment (Table 2). A retrograde urethrogram may be helpful before endoscopy to

provide anatomic detail of the urethra and help plan potential surgical procedures.

Urethral stricture disease, previous surgery, urinary tract infection, prostatism, and

diverticulae are the most commonly associated conditions found on radiographs and

endoscopy.

Table 2

Comorbid Conditions of 271 Patients

Presenting With Urethral Calculi

Comorbid conditions Number of patients

Urethral stricture 55

Prostatectomy 26

Recurrent urinary tract infection 20

Prostatism 20

Other surgery 11

Diverticulum 10

Neurogenic bladder 10

Phimosis 6

Posterior urethral valves 4

Trauma 4

Renal colic 4

Exstrophy/hypospadias 2

Some patients had more than one symptom, comorbidity

and treatment. Also, some articles did not provide complete

information. As a result, not all categories add up to 271.

Adapted from References 2–15.

Table 1

Symptoms of 271 Patients

Presenting With Urethral Calculi

Symptoms Number of patients

Pain 167

Lower urinary tract symptoms 104

Urinary retention 92

Palpable mass 60

Hematuria 26

Incontinence 22

Fistula 10

Bilharziasis 7

Urinary tract infection 5

Urethralgia 2

Some patients had more than one symptom, comor-

bidity and treatment. Also, some articles did not provide complete

information. As a result, not all categories add up to 271.

Data from References 2–15.

664 Schwartz

Treatment

Treatment of urethral stones depends on the location and cause of the stone and may

range from spontaneous passage to lithotomy with repair of the underlying pathology

(Table 3). In the male, proximal stones are usually pushed into the bladder and treated

by conventional modalities such as laser or ultrasonic lithotripsy (2,3). Middle and distal

urethral stones are typically endoscopically extracted, sometimes with the aid of a

meatotomy (3). Stones trapped at the fossa navicularis can be extracted using a safe and

rapid technique that requires only local anesthesia and basic surgical instruments (16).

Stones found within a urethral diverticulum, whether male or female, require surgical

excision with diverticulectomy and stone extraction. Similarly, urethral stricture disease

may be managed with urethrotomy or open repair when encountered. Pathologic inves-

tigation for occult malignancy should be obtained.

The tools available for endoscopic treatment are similar to those used in other parts

of the urinary tract. Laser, electrohydraulic, pneumatic, ultrasonic, extracorporeal

shockwave, and manual lithotripsy can be used to treat urethral stones. Which modality

is used depends on the technology available, preference and experience of the surgeon,

cost considerations, and anesthetic availability. There have been no studies directly

comparing various modalities to declare a clear benefit of one over another in the man-

agement of urethral calculi.

Prevention

Prevention of urethral calculi is aimed at treatment of the underlying disease. If the

stone is believed to arise from the upper urinary tract, a metabolic evaluation including

serum calcium and uric acid levels and a 24-hr urine collection should be performed.

Appropriate dietary counseling and medical therapy are provided based on these results.

Because urinary infection is a common finding, culture selective antibiotics should be

used when infection is diagnosed. Aggressive treatment of prostatism and urethral stric-

ture disease is recommended. The aim of treatment for these diseases is to reduce postvoid

residual urine volumes, enhance bladder emptying, and reduce the risk of infection.

Table 3

Treatment of 271 Patients Presenting With Urethral Calculi

Treatment Number of patients

Push into bladder and treat 105

Internal urethrotomy and stone extraction 51

Endoscopic in situ 41

Meatotomy 27

Open removal with repair of underlying disease 17

Open removal 17

Spontaneous passage 7

Lost to follow-up 4

Extracorporeal shockwave lithotomy 1

Some patients had more than one symptom, comorbidity and treatment. Also,

some articles did not provide complete information. As a result, not all categories

add up to 271.

Adapted from References 2–15.

Chapter 35 / The “Other” Stones 665

Finally, routine surveillance and appropriate intervention of known upper tract stones

may prevent future episodes of “urethral colic.”

PROSTATIC CALCULI

Etiology

Although the clinical manifestations of primary prostatic calculi are different from

bladder calculi, their pathogenesis may provide insight to lithogenesis in the urinary

tract. Historically, their pathogenesis is attributed to obstruction of the prostatic ducts,

formation of corpora amylacea, and accumulation of debris. This debris binds to the

calcium present in high concentrations in prostatic secretions forming stones that may

grow (17). Many investigators have found that prostatic secretions have a high calcium

concentration but concurrently high citrate levels bind the calcium making it unavailable

to precipitate mimicking the situation in the kidney and bladder (18,19). Multiple studies

have shown that prostatic calculi are composed almost exclusively of hydroxyapatite

(18–20). Fox determined the incidence of prostatic calculi to be 14% based on 3510

abdominal radiographs (17) although histopathological studies indicate a 70% preva-

lence (21).

The relationship of bacteria to prostatic calculi has been postulated by Meares (24).

He reported on three men with prostatism, who were found to have prostatic calculi and

persistent positive urine cultures. Open prostatectomy in two and transurethral resection

in one were curative of their symptoms and sterilized their urine. Finally, Sonergaard and

colleagues evaluated 300 prostates obtained from autopsy (25). They found 99% of the

glands contained stones. Also, the stones increased in size and number with age suggest-

ing their formation is a normal part of the aging process.

Symptoms

Prostatic calculi are rarely symptomatic and are usually diagnosed during prostatic

ultrasonography performed during prostate biopsy or pelvic computed tomography

performed for unrelated complaints. If the stones are related to bacterial growth, symp-

toms such as urgency, frequency, intermittency, and dysuria are likely to be present.

Chronic pelvic pain and perineal discomfort may be related to prostate stones but a

definite relationship has not been established.

Diagnosis

The vast majority of prostatic calculi are discovered incidentally during transrectal

ultrasonography or computed abdominal tomography performed for unrelated com-

plaints. Transrectal ultrasonography can also be used intraoperatively to guide transure-

thral resection of the offending calculi. Digital rectal examination can occasionally

suggest the presence of large peripheral stones. The relationship between serum pros-

tate specific antigen and prostatic calculi has not been established. It should be stressed

that the diagnosis of prostatic calculi does not warrant treatment. If it is determined that

lower urinary tract symptoms are originating from infected prostatic calculi attempts at

removal should be undertaken.

Treatment

Most prostatic calculi require no treatment. Occasionally men with lower urinary tract

symptoms or chronic infection may require definitive treatment. Mears performed open

perineal and retropubic prostatectomy and transurethral resection in three patients with

666 Schwartz

infectious stones. We have employed ultrasound-assisted transurethral prostatectomy in

two patients with pelvic pain syndrome and large prostatic calculi (unpublished data).

Directed resection resulted in an improvement in symptoms in both men. Because there

are inadequate reports in the literature to make unequivocal treatment recommendations

regarding prostatic calculi, patient treatment should be individualized and routine cul-

ture, cancer, and outlet obstruction investigation should be performed.

Prevention

Because of the infrequent occurrence of symptomatic prostatic calculi, significant

efforts at prevention have not been undertaken. Further investigation of prostatic calculi

may help elucidate the origin of other nonosseous stones. At this time there are no

recognized preventative measures.

SEMINAL VESICLE CALCULI

Calculi of the seminal vesicle, ejaculatory duct, and vas deferens are uncommon and

rarely of clinical significance. Since 1965, the English literature has produced eight case

reports of clinically significant seminal vesicle stones (26–33). The etiology, symptoms,

diagnosis, and treatment can be seen in Table 4. Figures 1 and 2 demonstrate an ejacu-

latory duct stone managed endoscopically. These stones occur so infrequently it is dif-

ficult to make recommendations on their clinical management. Sound urologic principles

of relieving obstruction, eradicating infection, and providing unimpeded urinary drain-

age will usually prove successful in their treatment.

Recent advances in and increased use of lower genitourinary tract imaging have

identified calculi in the prostate, seminal vesicles, and ejaculatory ducts with increasing

frequency. Kuligowska performed transrectal ultrasound on 276 men with low ejacu-

late-volume and azoospermia (34). Twelve (4.4%) men had stones: five (42%) in the

ejaculatory ducts, four (33%) in the vas deferens, and three (25%) in the seminal vesicles.

Cho performed magnetic resonance imaging in 17 men presenting with hemospermia

(35). Nineteen calculi were observed: five in the prostate, eight in the seminal vesicle,

four in the ejaculatory ducts, and two in müllerian duct cysts. Engin used magnetic

resonance imaging and transrectal ultrasound to evaluate 218 infertile men with low

ejaculate-volumes (36). Ejaculatory duct calcifications were found in 27% of the

azoospermic men and 6% of the nonazoospermic men. These studies suggest the use of

imaging to look for clinically significant calculi in men with infertility, especially low-

volume azoospermia. The significance of these calcifications and their affect on sperma-

tozoa are currently unknown.

BLADDER CALCULI

Etiology

Bladder calculi have afflicted man for thousands of years. Archeologists discovered

a stone resting in the pelvis of an ancient Egyptian skeleton dating back more than 7000

yr (37). Fortunately, over the last 50 yr, the incidence of vesical calculi in developed

countries has declined significantly and currently represents roughly 5% of all urinary

calculi in the Western world (38,39). Underdeveloped societies still suffer from endemic

bladder calculi, especially children, usually owing to diets rich in cereals and grains and

deficient in animal proteins. A high acid-ash and low-phosphate diet in conjunction with

dehydration from chronic diarrhea and malnutrition results in low urinary pH with

Chapter 35 / The “Other” Stones 667

Table 4

Eight Patients With Seminal Vesicle or Ejaculatory Duct Calculi

Age Presenting complaint

Previous surgery Imaging Stone analysis Treatment

7 • Recurrent • None • Abdominal radiograph +

• Not available • Open seminal

epididymo- • Abdominal ultrasound +

vesiculolithotomy

orchitis • Computed tomography +

• Digital rectal examination palpable

10 • Recurrent • Anorectal malformation

• Abdominal radiograph +

• Not available • Open seminal

epididymo- • Urethral fistula • Digital rectal examination palpable

vesiculolithotomy

orchitis • Bladder diverticulectomy

• Computed tomography +

• Ureteral reimplant • Intravenous pyelogram normal

12 • Inability to self • Myelomeningocele

• Retrograde urethrogram

• Calcium phosphate • Laser lithotripsy

catheterize • Spina bifida ejaculatory duct reflux

• Ejaculatory duct fulguration

25 • Painful • None • Transrectal ultrasonograph +

• Not available • Spontaneous passage

ejaculation • Digital rectal examination

normal

26 • Asymptomatic • Ureteral reimplant

• Abdominal radiograph +

• Not available • Observation

pyuria • Bladder neck repair

• Retrograde urethrogram

• Incision ureterocele ejaculatory duct reflux

32 • Azoospermia • None • Digital rectal examination palpable

• Calcium phosphate • Transurethral resection

• Transrectal ultrasonograph +

of the ejaculatory ducts

• magnetic resonance imaging +

41 • Renal colic • None • Intravenous pyelogram ectopic

• Carbonate • Open nephro-ureterectomy

• Irritative voiding ureter entering • Urate • Seminal vesiculectomy

symptoms into the seminal vesicle

• Phosphate

• Struvite

53 • Orchalgia • Two previous open

• Digital rectal examination palpable

• Not available • Transrectal excision

• Perineal pain seminal vesiculolithotomy

• Abdominal radiograph +

• Intravenous pyelogram normal

Adapted from References

6–

33.

667

668 Schwartz

Fig. 1. (A) Plain abdominal radiograph demonstrating a large calcification (arrow) overlying the

symphysis pubis; and (B)computed tomography of the pelvis confirming the location of the stone

within the ejaculatory duct.

Chapter 35 / The “Other” Stones 669

subsequent uric acid or ammonium acid urate stone formation. Magnesium ammonium

phosphate stones are also common in underdeveloped nations owing to high infection

rates and limited antibiotic therapy available in these areas. Western series report a high

incidence of calcium-based stones, reflecting compositions similar to those of upper

urinary tract calculi. A recent comprehensive review of 1440 children with urinary

calculi support the historical data presented above. Interestingly, they documented that

bladder stones were present in 60% of cases in the mid-1980s but decreased to 15% in

the mid-1990s (40).

Attempts to identify the inciting event in bladder stone formation have yielded inter-

esting results. African investigators analyzed nuclei and multiple layers of 42 pediatric

bladder stones using infrared spectrometry (41). The major constituents were ammo-

nium acid urate and calcium oxalate monohydrate. Eighty per cent of the nuclei con-

tained ammonium acid urate whereas 50% had calcium oxalate. Struvite and calcium

phosphate nuclei were not found in any of their stones. Analysis of the concentric layers,

however, revealed large amounts of struvite and calcium phosphate indicating that

infection may not be required for stone initiation, but once crystallization has started,

it may be a significant promoter of stone growth.

Fig. 2. (A) Cystoscopic view of the verumontanum with a stone visible in the left ejaculatory

duct. (B) A pediatric cystoscope was used to enter the ejaculatory duct to better visualize the

stone. (C) At a second setting the ejaculatory duct was incised with Collins knife exposing the

stone. (D) A 3 Fr tipless four-wire basket engaging the stone. The stone was extracted from the

duct and fragmented with the holmium laser.