2Surgical Management of Upper Urinary Tract Calculi 48 Kidney CalculiPelolithotomyNephrolithotomyAlthough stone-free rates of these modernsurgical techniques were excellent, morbidity was significant,and the search for new techniques and technologiescontinued.
3Ureteral CalculiUreterolithotomyEndourologyBefore the development of endoscopy attempts to blindly extractcalculi were not uncommon.
4The development of minimally invasive surgical techniques for the treatment of patients suffering from urinary lithiasis has beengreatly 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 techniquesof calculus removal, including ureteroscopy, percutaneousnephrolithotomy (PNL), and extracorporealshockwave lithotripsy (SWL).
5term endourology as closed controlled manipulation within the genitourinary tractUreteroscopyCurrently available ureteroscopes range from 54 to 70 cm inlength and have a tapered shaft diameter that increases proximally.As the tip of the ureteroscope is inserted into the ureter andpassed retrograde, the ureter is slowly dilated.Most modernureteroscopes have a single working channel, and some have asecond irrigation channel that serves to distend the ureter andmaintain visualization.
6Parallel to improvements in rigid and flexible ureteroscopes were advances in intracorporeal lithotripters, including ultrasonic,electrohydraulic, pneumatic, and laser probes, allowingefficient stone fragmentation through the miniaturized modernureteroscopic equipment.
7Percutaneous Stone Removal Subsequent advancesin endoscopes, imaging equipment, and intracorporeal lithotriptersallowed urologists and radiologists to refineThese percutaneous techniques through the late 1970s and early 1980sinto well-established methods for removal of upper urinary tractcalculi.
8Extracorporeal Shockwave Lithotripsy Examples of high-energy shockwaves include the blast effect associated with explosions, as well as the potentially windowshatteringsonic boom created when aircraft pass beyond the speed of sound.Engineers at Dornier Medical Systems in what wasthen West Germany, during research on the effects of shockwaves on military hardware, demonstrated that these shockwaves arereflectable and therefore focusable.The possibility of applyingshockwave energy to human tissue was discovered when, bychance, a test engineer touched a target body at the very momentof impact of a high-velocity projectile. The engineer felt a sensationsimilar to an electric shock, although the contact point at theskin showed no damage at all
9more than 1 million patients are treated annually with SWL. RENAL CALCULIThe 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 continuingadvancements 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 modalitiesavailable to the urologist has increased, new controversies regardingthe indications for these therapies have developed. Currently,urologists face the challenge of selecting the optimal treatmentmodality on the basis of the patient’s and the stone’s characteristics.Four minimally invasive treatment modalities are availablefor the treatment of patients with kidney stones and are discussedin this chapter: SWL, PNL, ureteroscopy, and laparoscopic stonesurgery.
10Most patients harboring “simple” renal calculi can be treated satisfactorily with SWL.However, there are otherpatients who are unlikely to achieve a successful outcome withSWL; factors associated with poor stone clearance rates after SWLinclude large renal calculi, stones within dependent orobstructed portions of the collecting system, stones ofcertain composition (cystine, calcium oxalate monohydrate,and brushite), and obesity or a body habitus thatinhibits imaging and targeting of the stone.For patientswith 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, orshould other treatment modalities be used?
11Bacteriologic evaluation of the urine is mandatory for all patients. The composition of any previous stone material passedor removed from the patient is extremely important. If previousstones have contained significant amounts of calcium oxalatemonohydrate (whewellite) or brushite, fragmentation with SWLmay be expected to be more difficult.
12most calyceal stones, in the absence of intervention, are likely to increase in size and causesymptoms of pain or infection.
13Staghorn calculi are those stones that fill the major part of the renal collecting system. Typically, they occupy the renal pelvis andbranch into most of the calyces, mimicking the horns of a deer .Most staghorn stones are composed of struvite. Until the early 1970s some physicians believedthat patients harboring staghorn calculi should not be treatedHowever, a better understanding of the naturalhistory of staghorn stones has evolved. It is now generally acceptedthat, if left untreated, a staghorn calculus is associated with progressivedeterioration of renal function. Additionally, morbiditiesassociated with an untreated staghorn stone include pain, recurrenturinary tract infection, and sepsis events.
14untreated struvite staghorn calculi eventually destroy the kidney and pose a significant risk to thepatient’s life.
15Stone burden (size and number) is perhaps the single most important factor in determining the appropriatetreatment modality for a patient with renal calculi.The negative effect of an increasing stone burden (sizeand number) on the results of SWL has been described
1650% to 60% of all solitary renal calculi are less than 10 mm in diameter . Treatment results of SWLfor this substantial group of patients aregenerally satisfactoryPatients with calculi between 10 and 20 mm are oftentreated with SWL as first-line management.
17Patients with stones larger than 20 mm should primarily be treated by PNL unless specific indicationsfor ureteroscopy are present (e.g., bleeding diathesis,obesity).
18Treatment Decisions by Stone Composition patients with suchstones (i.e., brushite, cystine, calcium oxalate monohydrate)should be treated by SWL only when the stoneburden is small (i.e., <1.5 cm).
19Renal Anatomic Factors There are certain anatomic factors, either congenital or acquired,that can hinder stone clearance after SWL. Congenital anomaliesmanifest not uncommonly in the upper urinary tract, and almostall that affect the drainage of the kidney are associated with anincreased incidence of calculous disease.Such abnormalitiesinclude ureteropelvic junction (UPJ) obstruction, horseshoekidney, and other ectopic or fusion anomalies as well as calycealdiverticula. Hydronephrosis, too, is associated with a failure toclear stone fragments after SWL.