Stone disease 3 Open surgery of kidney 54

Surgical Management of Upper Urinary Tract Calculi 48 Kidney Calculi Pelolithotomy Nephrolithotomy Although stone-free rates of these modern surgical techniques were excellent, morbidity was significant, and the search for new techniques and technologies continued.

Ureteral Calculi Ureterolithotomy Endourology Before the development of endoscopy attempts to blindly extract calculi were not uncommon.

The development of minimally invasive surgical techniques for the treatment of patients suffering from urinary lithiasis has been greatly dependent on technologic advances in the fields of fiberoptics, radiographic imaging, and lithotripsy (shockwave, ultrasonic, electrohydraulic, and laser). These advancements have accelerated the evolution of modern techniques of calculus removal, including ureteroscopy, percutaneous nephrolithotomy (PNL), and extracorporeal shockwave lithotripsy (SWL).

term endourology as closed controlled manipulation within the genitourinary tract Ureteroscopy Currently available ureteroscopes range from 54 to 70 cm in length and have a tapered shaft diameter that increases proximally. As the tip of the ureteroscope is inserted into the ureter and passed retrograde, the ureter is slowly dilated. Most modern ureteroscopes have a single working channel, and some have a second irrigation channel that serves to distend the ureter and maintain visualization.

Parallel to improvements in rigid and flexible ureteroscopes were advances in intracorporeal lithotripters, including ultrasonic, electrohydraulic, pneumatic, and laser probes, allowing efficient stone fragmentation through the miniaturized modern ureteroscopic equipment.

Percutaneous Stone Removal Subsequent advances in endoscopes, imaging equipment, and intracorporeal lithotripters allowed urologists and radiologists to refine These percutaneous techniques through the late 1970s and early 1980s into well-established methods for removal of upper urinary tract calculi.

Extracorporeal Shockwave Lithotripsy Examples of high-energy shockwaves include the blast effect associated with explosions, as well as the potentially windowshattering sonic boom created when aircraft pass beyond the speed of sound. Engineers at Dornier Medical Systems in what was then West Germany, during research on the effects of shockwaves on military hardware, demonstrated that these shockwaves are reflectable and therefore focusable. The possibility of applying shockwave energy to human tissue was discovered when, by chance, a test engineer touched a target body at the very moment of impact of a high-velocity projectile. The engineer felt a sensation similar to an electric shock, although the contact point at the skin showed no damage at all

more than 1 million patients are treated annually with SWL. RENAL CALCULI The primary goal of surgical stone management is to achieve maximal stone clearance with minimal morbidity to the patient. The introduction of SWL as well as continuing advancements in the field of endourology have allowed most patients with renal stones to be treated in a minimally invasive fashion. However, as the armamentarium of treatment modalities available to the urologist has increased, new controversies regarding the indications for these therapies have developed. Currently, urologists face the challenge of selecting the optimal treatment modality on the basis of the patient’s and the stone’s characteristics. Four minimally invasive treatment modalities are available for the treatment of patients with kidney stones and are discussed in this chapter: SWL, PNL, ureteroscopy, and laparoscopic stone surgery.

Most patients harboring “simple” renal calculi can be treated satisfactorily with SWL. However, there are other patients who are unlikely to achieve a successful outcome with SWL; factors associated with poor stone clearance rates after SWL include large renal calculi, stones within dependent or obstructed portions of the collecting system, stones of certain composition (cystine, calcium oxalate monohydrate, and brushite), and obesity or a body habitus that inhibits imaging and targeting of the stone. For patients with these clinical characteristics, alternative treatment modalities, such as ureteroscopy or PNL, should be considered. The urologist, then, when treating a patient with a renal calculus, must ask: Is the patient an appropriate candidate for SWL, or should other treatment modalities be used?

Bacteriologic evaluation of the urine is mandatory for all patients. The composition of any previous stone material passed or removed from the patient is extremely important. If previous stones have contained significant amounts of calcium oxalate monohydrate (whewellite) or brushite, fragmentation with SWL may be expected to be more difficult.

most calyceal stones, in the absence of intervention, are likely to increase in size and cause symptoms of pain or infection.

Staghorn calculi are those stones that fill the major part of the renal collecting system. Typically, they occupy the renal pelvis and branch into most of the calyces, mimicking the horns of a deer . Most staghorn stones are composed of struvite . Until the early 1970s some physicians believed that patients harboring staghorn calculi should not be treated However, a better understanding of the natural history of staghorn stones has evolved. It is now generally accepted that, if left untreated, a staghorn calculus is associated with progressive deterioration of renal function. Additionally, morbidities associated with an untreated staghorn stone include pain, recurrent urinary tract infection, and sepsis events.

untreated struvite staghorn calculi eventually destroy the kidney and pose a significant risk to the patient’s life.

Stone burden (size and number) is perhaps the single most important factor in determining the appropriate treatment modality for a patient with renal calculi. The negative effect of an increasing stone burden (size and number) on the results of SWL has been described

50% to 60% of all solitary renal calculi are less than 10 mm in diameter . Treatment results of SWL for this substantial group of patients are generally satisfactory Patients with calculi between 10 and 20 mm are often treated with SWL as first-line management.

Patients with stones larger than 20 mm should primarily be treated by PNL unless specific indications for ureteroscopy are present (e.g., bleeding diathesis, obesity).

Treatment Decisions by Stone Composition patients with such stones (i.e., brushite, cystine, calcium oxalate monohydrate) should be treated by SWL only when the stone burden is small (i.e., <1.5 cm).

Renal Anatomic Factors There are certain anatomic factors, either congenital or acquired, that can hinder stone clearance after SWL. Congenital anomalies manifest not uncommonly in the upper urinary tract, and almost all that affect the drainage of the kidney are associated with an increased incidence of calculous disease. Such abnormalities include ureteropelvic junction (UPJ) obstruction, horseshoe kidney, and other ectopic or fusion anomalies as well as calyceal diverticula. Hydronephrosis, too, is associated with a failure to clear stone fragments after SWL.