David A. Schulsinger

Effect of freezing parameters (freeze cycle and thaw process) on tissue destruction following renal cryoablation.

BACKGROUND AND PURPOSEnRenal cryoablation is a successful nephron-sparing treatment alternative for selected patients with small renal tumors. The purpose of this study was to compare the effects of the number of freeze cycles (one v two) and the thaw process (active v passive) on renal tissue following cryodestruction.nnnMATERIALS AND METHODSnSixteen female mongrel dogs (19.9 +/- 2.1 kg) were randomly divided into four groups and underwent transabdominal laparoscopic access by standard techniques. Tissue freezing was performed using argon gas following interstitial cryoprobe (3 mm) placement into the upper and lower poles of the left kidney. Single active (SA), single passive (SP) double active (DA) or double passive (DP) 15-minute treatment cycle(s) were carried out via the CRYOcare Cryosurgical Unit (Endocare, Irving, CA) on eight kidneys each. An active thaw process with helium gas or a passive thaw process was initiated after each freeze period. The cryoprobe was removed when the temperature reached 0 degrees C. Four weeks following cryosurgery, animals were sacrificed, and the renal tissue was evaluated grossly and histologically.nnnRESULTSnInterstitial cryoprobe temperatures decreased from 31.3 degrees C +/- 1.4 degrees C to -142 degrees C +/- 1.0 degrees C following the 15-minute freeze cycle. The temperature reached 0 degrees C significantly faster following active thaw than with the passive process (2.13 +/- 0.24 min/freeze cycle and 15.18 +/- 2.97 min/freeze cycle, respectively; P < 0.0001). Grossly, each lesion consisted of a central area of necrosis surrounded by a rim of white tissue. On microscopic examination, each lesion consisted of a central area of liquefaction necrosis (LN) surrounded by various degrees of fibrosis and granulation tissue admixed with residual parenchyma. The size of the LN was significantly different in tissues subjected to double and single freeze cycles when compared across both thaw processes (active and passive). There was no significant difference in the overall lesion volume following DA, DP, SA, or SP.nnnCONCLUSIONSnRenal cryodestruction via laparoscopic access achieves complete tissue ablation without complications. The double freeze cycle produced significantly larger areas of LN than the single freeze regardless of the thaw process. The type of thaw process did not affect the amount of tissue damage. Utilizing a double 15-minute freeze cycle with the faster active thaw process will effectively cryoablate renal tissue as well as significantly reduce overall operative time.

Intermittent Torsion: Association with Horizontal Lie of the Testicle

The importance of making an early diagnosis of intermittent testicular torsion cannot be over-emphasized. We report on 3 patients with recurrent episodes of severe testicular pain but who were pain-free at evaluation. All 3 patients were found to have a horizontal lie of the symptomatic testicle and a normal vertical axis in the contralateral asymptomatic testicle. Scrotal exploration revealed a bell-clapper deformity in all 3 patients. A history of recurrent scrotal pain and horizontal testicular lie, even in the absence of pain at the time of physical examination, is a strong indication for exploration and bilateral testicular fixation.

Case report : treatment of bilateral fibroepithelial polyps in a child

Ureteral fibroepithelial polyps are extremely rare benign lesions composed of stroma with a surface of normal transitional epithelium. Traditionally, symptomatic polyps were treated with open exploration and segmental resection. We describe the first case of bilateral polyps in a child. One was removed by segmental resection and the other by ureteroscopic laser surgery.

Unilateral Multicystic Dysplasia in 1 Component of a Horseshoe Kidney: Case Reports and Review of the Literature

We report on 3 pediatric patients with multicystic dysplasia involving 1 component of a horseshoe kidney. Including our cases, 18 cases of unilateral multicystic dysplasia in a horseshoe kidney have been reported. The clinical, radiological and pathological features of these cases are briefly reviewed. The association of multicystic dysplastic kidney and horseshoe kidney presents a unique diagnostic challenge. Because of the rarity of unilateral multicystic dysplasia in a horseshoe kidney and the size of the dysplastic component, which crossed the midline in our patients, we chose to excise that component. Cross-sectional imaging techniques, that is computerized tomography and magnetic resonance imaging, were helpful in diagnosis and in planning operative treatment.

Role of the NO System in Urinary Tract Obstruction

Obstructive uropathy with subsequent nephron injury is a major cause of renal damage and occurs in a significant number of urological diseases. Obstruction to the urinary tract can come from either intrinsic disease or external compression to the genitourinary system. The pathophysiology of urinary tract obstruction has been a subject of a number of recent reviews [1-31. In a large autopsy study of patients of all ages, frequency of urinary tract obstruction was 3.1%. Obstruction in the younger patient is usually due to a congenital anomaly; during young adulthood, the most common etiology is urinary stone disease, and later in life, the male can develop hydronephrosis secondary to prostatic disease. The terminology is confusing, with the termhydronephrosisbeing an anatomical description of a dilated ureter and collecting system. Better terms are eitherobstructive uropathyorobstructive nephropathywhich imply that there is actual damage to the urinary tract. In the latter setting, there is not only an anatomic change but a reduction in renal function due to the obstructive injury. The mechanism of injury to the nephron during obstruction remains an area of intense controversy. It is clear that this is not a pure pressure phenomenon although the ureteral pressure initially rises following obstruction. Subsequently, it falls and there is renal vasoconstriction which is injurious to the nephron. During the course of either complete or partial obstruction, there appears to be a complex interaction between renal vasoconstrictors and renal vasodilators. Accordingly, with the advent of knowledge concerning nitric oxide, studies have been initiated to define the role of nitric oxide system in obstructive injury. Therefore, in this chapter we will review the current information available concerning this system in experimental models of urinary tract obstruction.