Hyung Keun Park

Factors Influencing Renal Function Reduction After Partial Nephrectomy

PURPOSE We investigated factors determining the degree of functional reduction by measuring changes in individual renal function before and after partial nephrectomy. MATERIALS AND METHODS In 117 patients who underwent elective partial nephrectomy the glomerular filtration rate of the renal units with tumor from the diethylenetetramine pentaacetic acid renal scan was measured before and at a mean of 6.5 months after surgery. Kidney volume was calculated using computerized tomography. Of these patients 52 and 65 underwent open and laparoscopic partial nephrectomy, respectively. Satinsky clamps were used for renal artery-vein clamping in all patients. We analyzed patient, tumor and perioperative characteristics including surgical method with respect to changes in glomerular filtration rate. RESULTS Renal cell carcinoma was diagnosed in 101 (86.3%) patients. Between the laparoscopic and open partial nephrectomy groups significant differences were noted in tumor size (2.14 vs 3.72 cm, p <0.001) and warm ischemia time (33.5 vs 20.5 minutes, p <0.001). Reduction and percent reduction in glomerular filtration rate (13.3 vs 12.6 ml per minute per m(2), p = 0.662; 29.9% vs 33.2%, p = 0.337), and reduction and percent reduction in kidney volume (35.8 vs 36.4 cm(3), p = 0.886; 20.4% vs 24.0%, p = 0.151), respectively, were similar between the groups. On multivariate analysis renal volume reduction (%, p <0.0001) was the most significant, independent prognosticator for glomerular filtration rate reduction followed by polar location of the tumor (upper vs mid-lower pole, p = 0.012) and increasing age (p = 0.041). CONCLUSIONS Renal volume reduction, tumor location and patient age determine renal function after partial nephrectomy. In appropriate cases the laparoscopic method can show surgical and functional outcomes equivalent to those of the open method.

Association Between Metabolic Syndrome and the Presence of Kidney Stones in a Screened Population

BACKGROUND Components of metabolic syndrome have been associated with kidney stone disease, but little evidence is available to support a relationship between metabolic syndrome and kidney stone development in healthy large screened populations. STUDY DESIGN Cross-sectional analysis. SETTING & PARTICIPANTS Data were obtained from 34,895 individuals who underwent general health screening tests between January 2006 and December 2006 at the Asan Medical Center. PREDICTOR Metabolic syndrome was defined according to criteria established by the National Cholesterol Education Program Adult Treatment Panel III, American Heart Association, and National Heart, Lung, and Blood Institute. OUTCOMES & MEASUREMENTS The presence of kidney stones was evaluated using computed tomography or ultrasonography. RESULTS Of all those screened, 839 (2.4%) had radiologic evidence of kidney stones and metabolic syndrome was diagnosed in 4,779 (13.7%). The multivariable-adjusted OR for kidney stones increased with an increasing quintile of waist circumference and systolic/diastolic blood pressure (P < 0.001). Age, sex, hypertension, and metabolic syndrome status were independent risk factors for kidney stones. The presence of metabolic syndrome had an OR of 1.25 (95% CI, 1.03-1.50) for kidney stone prevalence. In participants with hypertension, the OR for the presence of kidney stones was 1.47 (95% CI, 1.25-1.71) compared with that for participants without hypertension after adjustment for other variables. LIMITATIONS Cross-sectional design, absence of stone composition. CONCLUSION Metabolic syndrome is associated with a significantly increased risk of kidney stone development. Our findings suggest the need for interventional studies to test the effects of preventing and treating metabolic syndrome on the risk of kidney stone development.

Followup of Unilateral Renal Function After Laparoscopic Partial Nephrectomy

PURPOSE We assessed the change in unilateral renal function after laparoscopic partial nephrectomy to determine factors affecting the course and factors predicting the postoperative glomerular filtration rate decrease. MATERIALS AND METHODS From prospectively collected data on 116 patients who underwent laparoscopic partial nephrectomy we evaluated the glomerular filtration rate of the operated kidney using diethylenetriaminepentaacetic acid scans done preoperatively, and 3 months, and 1, 2 and 3 years postoperatively. Kidney volume was measured from the arterial phase of dynamic computerized tomography of the kidney done before and 3 months postoperatively to calculate the volume reduction. We analyzed clinicopathological and operative factors with the potential to influence the perioperative glomerular filtration rate decrease. RESULTS In all patients the glomerular filtration rate was significantly decreased by 3 months postoperatively. It remained significantly lower compared to preoperative function despite the trend toward progressive recovery, which was noted until 3 years postoperatively. Recovery in individuals was significantly influenced by patient age (less than 55 vs 55 years or greater), medical comorbidities, tumor size (less than 2.5 vs 2.5 cm or greater), kidney volume reduction (less than 20% vs 20% or greater) and collecting system repair at surgery. Independent determinants of postoperative renal function were the preoperative glomerular filtration rate (β = 0.410, 95% CI 0.424-1.084; p <0.001), the percent of renal parenchymal volume reduction (β = 0.273, 95% CI 0.168-0.766; p = 0.003) and pelvicalyceal system repair (β = 0.284, 95% CI 2.960-15.788; p = 0.005). CONCLUSIONS Function of the kidney undergoing laparoscopic partial nephrectomy progressively recovers after a significant decrease immediately after surgery. Although recovery differs according to patient age, comorbidities and tumor size, factors that independently predicted the postoperative glomerular filtration rate decrease were the renal parenchymal volume reduction and pelvicalyceal system repair.

Cross-Cultural Application of the Korean Version of Ureteral Stent Symptoms Questionnaire

PURPOSE We validated the Korean version of the Ureteral Stent Symptoms Questionnaire (USSQ) in patients with an indwelling ureteral stent. MATERIALS AND METHODS Linguistic validation of the original USSQ was performed through a standard process including translation, back translation, and pilot study. A total of 65 patients who underwent ureteroscopic surgery were asked to complete the Korean USSQ as well as EuroQOL (male and female), the International Prostate Symptom Score (male), and Urogenital Distress Inventory-6 (female). Patients were evaluated at weeks 1 and 2 after stent placement and at week 4 after removal. Sixty-four healthy subjects without a ureteral stent were also asked to complete the Korean USSQ once. The psychometric properties of the questionnaire were analyzed. RESULTS Internal consistencies (Cronbach α coefficients: 0.73-0.83) and test-retest reliability (Spearman correlation coefficient: ≥0.6) were satisfactory for urinary symptom, body pain, general health, and work performance domains. Most USSQ domains showed moderate correlations with each other. Convergent validity determined by correlation between other instruments and corresponding USSQ domain was satisfactory. Sensitivity to change and discriminant validity were also good in most domains (P<0.01). Only a small proportion of the study population had an active sexual life, with the stent in situ, limiting its analysis. CONCLUSIONS The Korean version of the USSQ is a reliable and valid instrument that can be self-administered by Korean patients with a ureteral stent in the clinical and research settings. Further clinical studies in the Korean settings would be useful to provide robust data on sensitivity to change.

Long-term outcome of secondary endopyelotomy after failed primary intervention for ureteropelvic junction obstruction

Objective:  To evaluate the long‐term outcome of secondary endopyelotomy after failed primary intervention for uretero‐pelvic junction (UPJ) obstruction and to assess the effect of preoperative parameters on treatment outcome.

Covered Retrievable Prostatic Urethral Stents: Feasibility Study in a Canine Model

PURPOSE To evaluate the feasibility of use of a covered, retrievable prostatic urethral stent and to determine urethrographic and histologic changes in the prostate induced by the stent in a canine model. MATERIALS AND METHODS Polytetrafluoroethylene-covered retrievable nitinol stents were placed in the normal prostatic urethras of 13 dogs. The stents were removed 8 weeks after placement. The dogs were killed immediately after stent removal (group 1, n = 5) or 8 weeks after stent removal (group 2, n = 8). Retrograde urethrograms were obtained every 2 weeks after stent placement and after stent removal in dogs that had not been killed. The histologic changes in the prostate were compared between the two groups. RESULTS Stent placement was technically successful in all dogs. In two dogs, a second stent was placed because of migration of the first stent into the urinary bladder. Stent removal was successful in 12 dogs. One stent was removed in its expanded state. On follow-up urethrograms, dilation of the prostatic urethra persisted until animals were killed (P = .14). The mucosal hyperplasia that occurred after stent placement at both ends of the stent gradually decreased after stent removal (P < .001). Histologic examination revealed prostate glandular atrophy and periurethral fibrosis, which did not differ between the two groups (P = .72 and P = .83, respectively). Papillary hyperplasia of the uroepithelium and submucosal inflammatory cell infiltration was decreased significantly in group 2 compared with group 1 (P = .002, P = .011, respectively). CONCLUSIONS Covered retrievable prostatic urethral stents seem to be feasible for use in the canine prostatic urethra. The stent-induced prostatic urethral dilation and prostate glandular atrophy persist until 8 weeks after stent removal.

Cystoscopic injection of N‐butyl‐2‐cyanoacrylate followed by fibrin glue for the treatment of persistent or massive vesicourethral anastomotic urine leak after radical prostatectomy

Vesicourethral anastomotic urine leak is a common postoperative complication of radical prostatectomy. Herein we describe a novel method for the treatment of this complication.

Paradoxical air embolism during percutaneous nephrolithotomy: a case report.

Air embolism is a rare complication of percutaneous nephrolithotomy. Patent foramen ovale, which is necessary in fetal circulation, is a potential route for emboli arising from the venous system to enter the systemic arterial circulation, resulting in paradoxical air embolism syndrome. A case of paradoxical air embolism during percutaneous nephrolithotomy is presented. To our knowledge, this is the first report of paradoxical air embolism associated with patent foramen ovale during percutaneous nephrolithotomy.

Multimodal treatments of cystine stones: an observational, retrospective single-center analysis of 14 cases.

Purpose To document the experiences of a single institution in evaluating the clinical courses and treatment outcomes of patients with cystine stones. Materials and Methods The clinical data of 14 patients with cystine stones who were treated at our institution from March 1994 to July 2012 were reviewed. These data included age at first visit, gender, family history, body mass index, presence of a single kidney, stone locations, stone burden, routine urinalysis, and culture. In addition, we also analyzed data on surgery, shock wave lithotripsy, medical treatment, stone recurrence or regrowth, and overall treatment success rates. Results The mean age of our patients at their first visit was 19.6±5.0 years, and eight patients were males. The median stone burden and mean urine pH before each surgery were 6.5 cm2 and 6.5±0.9, respectively. Two patients had a family history of cystine stones. Patients underwent surgery an average of 2.7 times. The median interval between surgeries was 27.3 months, and 1 open surgery, 12 percutaneous nephrolithotomies, and 25 ureterorenoscopies were performed. Potassium citrate or sodium bicarbonate was used in nine cases. D-Penicillamine was continuously used in three patients. Patients had an average incidence of 3.2 recurrences or regrowth of stones during the median follow-up period of 60.5 months. Conclusions Patients with cystine stones have high recurrence or regrowth rates and relatively large stone burdens. Adequate treatment schedules must therefore be established in these cases to prevent possible deterioration of renal function.

Effect of output voltage distribution on stone comminution efficiency during shockwave lithotripsy in renal or ureteropelvic junction stones: A preliminary study

Abstract Objective. This study evaluated stone comminution efficiency according to the distribution of the lithotripter output voltage during extracorporeal shockwave lithotripsy (SWL) of renal or ureteropelvic junction (UPJ) stones. Material and methods. Sixty-two patients with a single radiopaque renal or UPJ stone of surface area about 50–400 mm2 were prospectively randomized to receive a total of 2400 shocks per session according to one of three shock protocols: group A, output voltage was increased from 25% to 35% to 45% with 800 shocks per voltage; group B, constant output voltage of 35%; group C, decreasing output voltage from 45% to 35% to 25%. SWLs were carried out using a fourth generation electroconductive lithotripter, the Sonolith Vision, without anesthesia. The stone-free (SF) and success (SF + clinically insignificant residual fragment) rates were assessed. Results. Patient demographics, body mass index, stone burden, laterality and stone locations were comparable among the three groups. There were no differences in the cumulative success rates (30%, 32% and 35% after the first session for groups A, B and C, respectively; 65%, 50% and 65% after the second session; and 80%, 68% and 75% after the third session). The cumulative SF rates and complications showed no differences among the three groups. Conclusions. In this preliminary study, manipulation of the lithotripter output voltage distribution did not affect stone comminution efficiency for renal or UPJ stones. This finding should be confirmed by larger studies including more patients.