Biomedical subjects

Samuel C Kim

Publications and source records attributed to Samuel C Kim.

At least 19 recordsLinked to original sources

PubMed2006

Percutaneous nephrolithotomy for ectopic kidneys: over, around, or through.

OBJECTIVES: The treatment of patients with complex urolithiasis in ectopic kidneys can be challenging. Because the location of an ectopic kidney can vary, each case requires a unique and, at times, unconventional approach. We reviewed the techniques we have developed to treat such patients, including laparoscopic-assisted tubeless, transhepatic, and transiliac percutaneous nephrolithotomy (PNL). METHODS: We performed a retrospective analysis of all patients with congenital pelvic kidneys who underwent PNL at our institution. Six patients underwent laparoscopic-assisted PNL, one underwent transiliac PNL, and one underwent transhepatic PNL. All laparoscopic-assisted procedures were performed tubeless, with an internalized ureteral stent placed at the conclusion of the procedure. RESULTS: All patients underwent successful PNL. On computed tomography, performed on the morning of postoperative day 1, all patients who underwent laparoscopic-assisted PNL were stone free. The patients who underwent transiliac PNL and transhepatic PNL required secondary procedures to attain a stone-free status. The mean length of hospitalization was 3 days for the laparoscopic-assisted cohort, 1 day for the transhepatic patient, and 3 days for the transiliac patient. CONCLUSIONS: For the patient with a large or complex stone burden in an ectopic kidney, laparoscopic-assisted PNL is the optimal treatment. Performing such a procedure tubeless may be associated with a reduced hospital stay. For those patients with a hostile peritoneal cavity owing to prior surgical exploration, consideration should be given to a more individualized approach.

Adult↗

PubMed2006

Use of lower pole nephrostomy drainage following endorenal surgery through an upper pole access.

PURPOSE: PNL via an UP puncture is efficient for treating complex stone disease. Access via the UP can provide better visualization, allowing greater stone clearance with a rigid instrument due to its more favorable alignment with the axis of the intrarenal collecting system. However, the presence of a NT through the upper pole tract, especially with a supracostal puncture, can generate significant patient discomfort. We reviewed our experience with a technique using tubeless UP access for PNL with concomitant placement of a NT via a LP calix. MATERIALS AND METHODS: We performed a retrospective review of our experience using tubeless UP access for PNL with concomitant placement of an LP NT for postoperative drainage. Patient demographics, the number and location of accesses, stone size, stone-free rates, concurrent/additional procedures and complications were recorded. RESULTS: A total of 63 tubeless UP accesses were performed in 62 patients undergoing PNL, including unilateral access in 61 and bilateral access in 1. Supracostal UP punctures were used in 58 patients, including 40 above the 12th, 17 above the 11th and 1 above the 10th rib. Each patient underwent at least 2 accesses and 3 had 3 or more accesses placed. LP access was nondilated in 37 patients and dilated in 26. Of the patients 56.6% were stone-free after a single procedure, increasing to 96.2% following secondary procedures. Three of the 62 patients (4.8%) required transfusion, 3 (4.8%) required intervention for pleural morbidity and 1 (1.6%) required a stent for a nonsealing upper pole access. CONCLUSIONS: Tubeless UP access provides maximal efficiency for stone clearance during PNL, while minimizing the morbidity of an intercostal tube.

Adolescent↗

PubMed2006

Changing composition of renal calculi in patients with neurogenic bladder.

PURPOSE: Renal calculi are a significant source of morbidity for patients with neurogenic bladder. Calculi from patients with NB have traditionally been composed primarily of struvite and carbonate apatite secondary to chronic urea-splitting bacteriuria. In the current era there have been great improvements in the urological rehabilitation of patients with NB. We defined the composition of renal calculi in a contemporary cohort of patients with NB due to spinal cord injury or myelomeningocele who underwent percutaneous nephrolithotomy. MATERIALS AND METHODS: We performed a retrospective evaluation of all patients with NB due to SCI or MM who underwent PNL between January 2002 and January 2005. RESULTS: A total of 32 patients with NB (14 with SCI, 18 with MM) underwent PNL in this period. Stones were infectious in etiology in 37.5% (12 struvite/carbonate apatite) and metabolic in 62.5% (1 uric acid, 2 calcium oxalate monohydrate, 2 brushite, 6 hydroxyapatite, 9 mixed hydroxyapatite/calcium oxalate). All patients with struvite calculi were infected with urea-splitting bacteria on preoperative urine culture. CONCLUSIONS: Patients with neurogenic bladder are traditionally thought to harbor infection related calculi. These data demonstrate that many contemporary patients will be found to have calculi of a metabolic etiology. Although patients with NB still have renal calculi, advances in urological treatment may have affected the composition of their calculi, as metabolic stones are becoming more commonly identified. When metabolic components are identified, stone activity may be attenuated with appropriate metabolic evaluation, pharmacological therapies and dietary modifications.

Adolescent↗

PubMed2006

Endoscopic evidence of calculus attachment to Randall's plaque.

PURPOSE: It has been proposed that calcium oxalate calculi begin as small stones attached to the renal papillae at sites of Randall's plaque. However, no study has investigated the prevalence of attached stones in calcium oxalate stone formers or the relationship between stone attachment site and Randall's plaque. In this study we used endoscopic examination of renal papillae in stone formers undergoing percutaneous nephrolithotomy to investigate both issues. MATERIALS AND METHODS: Idiopathic calcium oxalate stone formers undergoing PNL for stone removal were enrolled in this study. Multiple papillae were examined and images were recorded by digital video. The presence or absence of papillary plaque and attached stones was noted, as was the site of stone attachment. RESULTS: In 23 patients, 24 kidneys and 172 renal papillae were examined. All kidneys were found to have papillary plaque and 11 of the patients had attached stones. Most papillae (91%) contained plaque. CONCLUSIONS: The prevalence of attached stones in calcium oxalate stone formers (48%) is greater than that previously reported for the general population. Attachment appears to be on Randall's plaque. The high prevalence of attached stones and the appearance of the attachment site are consistent with a mechanism of calcium oxalate stone formation in which stones begin as plaque overgrowth.

Calcium Oxalate↗

PubMed2006

Acute effects of percutaneous tract dilation on renal function and structure.

BACKGROUND: Percutaneous nephrolithotomy (PCNL) is performed on a routine basis for the rapid and efficient removal of large caliceal stones. After percutaneous puncture, rigid dilators or an inflatable balloon are used to dilate the nephrostomy tract to allow access to the collecting system for stone removal. Little is known of the acute impact of tract dilation procedures on renal function. MATERIALS AND METHODS: We compared renal hemodynamic and excretory function in female pigs immediately before and up to 5 hours after percutaneous nephrostomy (PCN) using sequential Amplatz dilators (N = 8) or Nephromax balloon inflation (N = 7) and control pigs with no PCN access (N = 8). We also examined renal function in patients undergoing PCNL. RESULTS: The two PCN procedures produced a renal lesion of comparable size and morphology, as well as similar changes in renal function. Glomerular filtration rate (GFR), renal plasma flow (RPF), and urinary sodium excretion (U(Na)V) were significantly reduced in Amplatz- and Nephromax-treated kidneys throughout the 5-hour observation period, by about 50%, 60%, and 80%, respectively. In control pigs, GFR and RPF remained stable and U(Na)V declined progressively to about 50% of baseline over the course of the experiment. The contralateral kidney showed changes in renal function similar to those in the PCN-treated or control kidney in all three groups. A retrospective analysis of 196 adults with normal renal function who underwent unilateral PCNL using the Nephromax balloon dilator revealed a significant increase in serum creatinine of 0.14 mg/dL at 1 day. CONCLUSION: Both animal and human studies show that PCN is associated with an acute decline in renal function.

Animals↗

PubMed2006

Pre-percutaneous nephrolithotomy opacification for caliceal diverticular calculi.

Caliceal diverticula harbor calculi in as many as 50% of cases. Such stones rarely pass spontaneously. Various stone-removal techniques have been used, with percutaneous techniques generally having the best results. In patients with nonradiopaque stones or in whom the diverticulum does not opacify when contrast is instilled retrograde or by intravenous urogram, contrast can be instilled directly into the cavity with CT or ultrasound guidance. Three such cases are described, with good results.

Adolescent↗

PubMed2006

Calcium oxalate calculi found attached to the renal papilla: Preliminary evidence for early mechanisms in stone formation.

BACKGROUND: Calculi are commonly found attached to the renal papilla in calcium oxalate (CaOx) stone formers, but the mechanisms by which stones form in this manner are not well established. MATERIALS AND METHODS: Data are presented from three attached stones collected from different patients. Stone morphology and composition were determined using micro computed tomography (CT) and infrared microspectrometry. RESULTS: One of the stones was composed of CaOx with a peripheral region of apatite, such as might have come from a Randall's plaque. Another stone was covered with large CaOx crystals but contained at least two layers of apatite, with no apatite regions exposed at the surface. The third stone contained CaOx with inclusions of apatite and more apatite on its surface, along with a substantial volume of poorly mineralized material that could not be identified. CONCLUSIONS: The complexity of these stones and their differing morphologies do not by themselves allow inference of the mechanism of stone formation. Future work will require the careful documentation of attached stones on the papilla, as well as study of the papilla after the stone has been removed, before it can be determined whether such diverse CaOx stones originate from the same or different underlying etiologies.

Apatites↗

PubMed2006

Holmium laser enucleation of the prostate for prostates of >125 mL.

OBJECTIVE: To examine a group of patients treated with holmium laser enucleation of the prostate (HoLEP) and with the bladder outlet obstructed by an exceptionally large (>125 mL) prostate, as such men are often not considered candidates for endoscopic treatments and historically have required open surgery. PATIENTS AND METHODS: We analysed retrospectively all patients with prostates of > 125 mL on transrectal ultrasonography (TRUS) who underwent HoLEP between January 2000 and January 2005. RESULTS: Eighty-six patients were identified; their mean (range) age was 72.6 (48-90) years and prostate volume 170.2 (125-309) mL. Their mean preoperative prostate-specific antigen (PSA) level was 9.82 ng/mL and preoperative American Urologic Association symptom score (AUA-SS) was 19.6. The mean operative duration and hospital stay were 128.1 min and 26.1 h, respectively. The mean weight of tissue enucleated was 140.2 g. At the 1-month follow-up the mean AUA-SS (63 men) was 8.4 and at 6 months (35 men) it was 6.4. The mean serum PSA level in 48 patients was 0.96 ng/mL, a reduction of 90%. TRUS measurements in 20 patients gave a mean prostate volume of 30.8 mL, a reduction of 82%. At the 1-year follow-up the mean AUA-SS of 22 patients was 5.1. CONCLUSIONS: The present report details the largest series of patients, with the largest mean prostate size, treated by any endoscopic surgical method. HoLEP may be the ideal treatment for men with prostates of > 125 mL with symptoms of bladder outlet obstruction.

Aged↗

PubMed2005

High-powered holmium-laser ablation: comparison of setting effectiveness using tissue-surrogate model.

BACKGROUND AND PURPOSE: The 100-W holmium laser, in conjunction with a sidefiring 550-microm fiber, can ablate prostate glands as large as 40 g to relieve lower urinary-tract symptoms. We evaluated the effect of various setting combinations on ablation efficiency using beef kidney as a tissue-surrogate model. MATERIALS AND METHODS: Beef kidney specimens (mean weight 44.8 +/- 3.1 g) were secured in a cylinder, which was submerged in a water-filled tank through which a 27F resectoscope and 550-microm sidefiring fiber were positioned. Four energy/frequency combinations were tested, with each used to treat 10 kidney specimens. The difference between the mean pretreatment and post-treatment weights of each treatment group were compared statistically with Student's t-test. RESULTS: The largest mean weight difference after treatment (8.94 +/- 2.38 g) was achieved using 3.2 J and 25 Hz. This mass reduction was significantly greater than that of all other combinations except 2.5 J and 40 Hz. CONCLUSIONS: Use of the 3.2 J and 25 Hz setting combination resulted in the greatest amount of ablation in this tissue-surrogate model, suggesting that maximal energy settings may provide an advantage in tissue vaporization using the 100-W holmium laser. Clinical assessment must be performed to substantiate these findings.

Animals↗

PubMed2005

Using and choosing a nephrostomy tube after percutaneous nephrolithotomy for large or complex stone disease: a treatment strategy.

BACKGROUND AND PURPOSE: Percutaneous nephrolithotomy (PCNL) is a well-accepted technique for removal of large or complex renal calculi. However, little attention has been paid to strategies for nephrostomy tube (NT) selection. We reviewed the reasons for selecting three types of NT after PCNL for large or complex stone disease. PATIENTS AND METHODS: A series of 106 consecutive renal units undergoing PCNL for stone burdens >2 cm by a single surgeon (JEL) were reviewed. Noncontrast CT (NCCT) was carried out on postoperative day 1, and secondary procedures were performed if fragments remained. The NTs studied were 8.5F and 10F Cope loops (CP), 20F reentry Malecot catheters (REM), and 20F circle loops (CL). Patient demographics, access site and number, complications, and stone type were examined. "Stone free" was defined as a negative NCCT or negative second-look PCNL. RESULTS: A total of 134 accesses were created in 106 renal units: 35 upper, 7 mid, and 92 lower; however, only 111 NTs were placed: 85 CP (76.6%), 19 REM (17.1%), and 7 CL (6.3%). Sixteen accesses were performed tubeless; all but two were in the upper pole. All 16 of these renal units had a concomitant NT placed in the lower pole. Multiple sites were accessed in 21 patients; 7 of these patients had CL placed. Five of ten patients with spinal-cord injury had REM/CL placed. Nineteen REM were placed: 10 for drainage of infection, and 9 for difficult anatomy. All renal units were rendered stone free: 31.1% with a single procedure and 95.6% with one or two procedures. There were no difficulties with drainage or access for secondary PCNL regardless of the NT employed. Complications included two hydrothoraces, one arteriovenous fistula, and one ureteral perforation. Three of four renal units in patients requiring transfusions underwent bilateral PCNL, and at least one renal unit required multiple accesses. Of kidneys with infection stones, 57.1% required REM or CL; only 12.0% of nonstruvite stones necessitated REM or CL. CONCLUSIONS: All patients having PCNL done for complex stone disease should have an NT placed; however, small (8.5F-10F) CP suffice in most cases and can provide greater patient comfort. To minimize pleural morbidity, tubeless upper-pole access should be considered if the kidney is judged to be stone free at the conclusion of PCNL. Circle loops are useful when multiple accesses are necessary, whereas REM are appropriate if access is difficult, gross residual stone remains, or pain is not an issue (i.e., spinal-cord injury).

Adult↗

PubMed2005

Change in serum prostate specific antigen concentration after holmium laser enucleation of the prostate: a marker for completeness of adenoma resection?

BACKGROUND AND PURPOSE: Holmium laser enucleation of the prostate (HoLEP) is a well-established technique for the treatment of benign prostatic hyperplasia (BPH). To date, changes in serum prostate specific antigen (PSA) after HoLEP have not been published. We hypothesized that HoLEP produces a diminution in PSA similar to that produced by the gold-standard therapies for BPH. To test this hypothesis, we have examined PSA data before and after HoLEP from two institutions performing high volumes of this procedure. PATIENTS AND METHODS: Between August 1998 and September 2004, 509 HoLEPs were performed at two institutions for which complete PSA data were available. Preoperative demographic and transrectal ultrasonography (TRUS) volume measurements were recorded; postoperative pathology and TRUS volume were obtained. Change in PSA as a function of the weight of prostate resected and the relation of preoperative TRUS volume to PSA was determined. RESULTS: The average weight of adenoma resected was 49.8 g (range 5-300 g) in the McGill group and 90.4 g (range 7.9-312 g) in the Methodist Hospital group. The mean decrease in PSA was 81.7% in the McGill group (range 6.0-1.1 ng/mL; P < 0.0001) and 86.0% in the Methodist Hospital group (range 8.6-1.2 ng/mL; P < 0.0001). Log transformed preoperative PSA correlated well with TRUS volume (r = 0.45), as did the weight of adenoma resected with absolute change in PSA (r = 0.38). The TRUS volume decreased significantly, from 111.9 cc to 26.5 cc, in the Methodist Hospital group (P < 0.0001). CONCLUSION: The HoLEP procedure produces a significant diminution in PSA that correlates well with the weight of adenoma resected. Measurement of PSA may be a useful tool for the objective assessment of ablative therapies for BPH, as the reduction in PSA corresponds well with the amount of adenoma removed.

Adenoma↗

PubMed2005

Holmium laser enucleation of the prostate: a comparison of efficiency measures at two institutions.

BACKGROUND AND PURPOSE: Holmium laser enucleation of the prostate (HoLEP) is perceived to be technically difficult, time consuming, and inefficient. We assessed the efficiency of HoLEP by documenting the technical features of the procedure at two hospitals located on different continents. PATIENTS AND METHODS: A retrospective analysis of all patients who underwent HoLEP at the Methodist Hospital of Indiana and Tauranga Hospital in New Zealand was performed. A series of 40 patients from the Indiana cohort were pair-matched, by the weight of prostate tissue retrieved, with 40 patients from the New Zealand cohort. Enucleation time and morcellation time were compared in the two groups. RESULTS: The mean weight of the tissue retrieved from the Indiana cohort was 27.1 g and that from the New Zealand cohort was 22.9 g (P = 0.41). The mean enucleation times were 47.6 minutes and 29.2 minutes, respectively (P < 0.001). The mean morcellation times were 9.9 minutes and 7.7 minutes (P = 0.201). The mean rates of enucleation were 0.58 g/min and 0.71 g/min (P = 0.17). The mean rates of morcellation were 3.4 g/min and 4.3 g/min (P = 0.20). The HoLEP efficiency increased as a function of gland size (R(2) = 0.56). CONCLUSIONS: Holmium laser enucleation of the prostate is a reproducible technique, as there is little variation in efficiency from one surgeon to another. Furthermore, the efficiency of HoLEP increases as prostate size increases, which suggests that HoLEP may be an ideal treatment for men with large prostates.

Holmium↗

PubMed2005

Shock wave lithotripsy of stones implanted in the proximal ureter of the pig.

PURPOSE: Ureteral stones can be difficult to treat with shock wave (SW) lithotripsy. A strategy for lithotripsy of proximal ureteral stones is to push them back into the renal pelvis prior to administering SWs. However, push-back is invasive and not always possible. Since there are few clues to suggest how best to treat ureteral stones with SWs in situ, we developed an animal model for research on lithotripsy for ureteral stones. MATERIALS AND METHODS: Gypsum model stones were implanted bilaterally in the proximal ureter and renal calix of the pig via percutaneous access. Lithotripsy was performed using a HM3 lithotripter (Dornier Medical Systems, Marietta, Georgia) and stones at each location were treated with the same dose (400 SWs, 20 kV and 30 SWs per minute). Fragments were collected and the percent increase in projected surface area of the particles was determined. RESULTS: The breakage (mean percent area increase) of stones implanted in the proximal ureter was significantly less than that of stones located in the renal calix treated with the same dose of shock waves (134% vs 327%, p <0.001). Also, stones that were fully confined by the ureter did not break as well as stones located at the ureteropelvic junction. This indicates that the physical environment surrounding a stone can have a significant effect on the efficiency of SW action. CONCLUSIONS: The observation that stones implanted in the ureter showed decreased breakage compared with stones in the kidney is consistent with clinical experience. This finding is a valuable and even essential prerequisite for any experimental animal model system intended for the study of SW action in the breakage of ureteral stones.

Animals↗

PubMed2005

Stone formation is proportional to papillary surface coverage by Randall's plaque.

PURPOSE: Randall's plaques are common in calcium oxalate (CaOx) stone formers (SF). Plaque coverage correlates directly with urine calcium excretion and inversely with urine volume. We hypothesize that plaque coverage should increase proportionally with increasing stone number. We measured plaque areas in idiopathic CaOx stone formers and nonstone formers (NSF), and identified significant relationships with quantified stone histories. MATERIALS AND METHODS: A total of 13 SFs and 4 control NSFs underwent nephroscopic papillary mapping with representative still images and MPEG (Moving Pictures Experts Group) movies used to identify plaque and papillary borders. Stone histories were obtained through patient interviews, and from medical records and radiographs. The relationship of plaque coverage to clinical stone events was assessed by general multivariate linear modeling. Log transformation normalized the distribution of percent plaque coverage and stone number. RESULTS: Plaque surface area in SFs differed significantly from that in NSFs (p <0.0001). The duration of stone disease and the log transformed percent plaque coverage correlated significantly with the number of stones (0.677 and 0.620, p = 0.003 and 0.008, respectively). On multivariate analysis and correcting for the duration of stone disease total percent plaque coverage correlated significantly with the number of stones (R = 0.496, p = 0.05). Disease duration and plaque coverage did not correlate significantly (p = 0.257). CONCLUSIONS: Percent plaque coverage directly correlates with the number of stones formed even when corrected for the duration of stone disease. However, plaque coverage does not correlate with the duration of stone disease. These results support the hypothesis that the pathogenesis of CaOx stones begins with Randall's plaques.

Biopsy↗

PubMed2005

Percutaneous nephrolithotomy for caliceal diverticular calculi: a novel single stage approach.

PURPOSE: Current percutaneous treatment of symptomatic caliceal diverticular calculi involves renal access, stone removal, dilation of the diverticular communication, fulguration of the cavity and placement of a nephrostomy tube. We reviewed the outcomes of patients undergoing a novel single stage percutaneous nephrolithotomy technique for radiopaque caliceal diverticular stones that eliminates ureteral catheterization and entry into the renal collecting system. MATERIALS AND METHODS: A total of 21 patients (8 male and 13 female including 1 bilateral) with a mean age of 42.4 years underwent percutaneous nephrolithotomy for caliceal diverticular stones from February 2001 to May 2003. Of the diverticula 12 were upper pole, 4 were interpolar and 6 were lower pole. Infracostal access was established by the urologist directly onto the radiopaque stones without the aid of a ureteral catheter. After balloon tract dilation a 30Fr Amplatz sheath was placed and following stone removal the diverticulum was fulgurated. The infundibulum was neither cannulated nor dilated. A 20Fr red rubber catheter or an 8.5Fr Cope loop was placed into the diverticulum. Stone-free status was assessed by noncontrast computerized tomography on postoperative day 1 (POD1). The drainage tube was removed if there was no urine drainage and the kidney was stone-free. Excretory urography was performed at 3 months to evaluate diverticular resolution. RESULTS: Of 21 patients 20 were discharged home tubeless on POD1 and 18 of 21 (85.7%) renal units were stone- free on POD1 noncontrast computerized tomography. Mean operative time was 58.5 minutes and mean stone burden was 138.9 mm. Mean stone diameter was 11.6 mm and mean diverticular diameter was 15.3 mm. Of 22 renal units 16 had followup excretory urography. All diverticula decreased in size and 14 (87.5%) had complete resolution. CONCLUSIONS: In patients with symptomatic radiopaque caliceal diverticular stones, a single stage procedure without the need for ureteral catheterization combined with direct infracostal diverticular puncture allows for a rapid procedure with little morbidity.

Adolescent↗

PubMed2005

Histopathology of human renal tumors after laparoscopic renal cryosurgery.

PURPOSE: Laparoscopic renal cryoablation is a nephron sparing treatment alternative for selected patients with small renal tumors. The acute tumoricidal effects of cryosurgery on human renal tumors and in experimental models have been reported previously. For cryoablation to be a viable option in the treatment of renal tumors, it must induce not only acute tissue injury but also sustain permanent tissue necrosis and cellular death, in addition to affording an adequate surgical margin free of viable tumor. We report on the longer term effects of in vivo human tumor tissue destruction by cryosurgery and describe the histopathology of a cryoablated renal lesion. MATERIALS AND METHODS: Three patients in our series who were treated with laparoscopic renal cryosurgery subsequently underwent radical nephrectomy of the cryoablated renal unit. RESULTS: All patients underwent uneventful cryosurgery. Two patients were found to have positive post-cryosurgery biopsies, while a new, metachronous lesion developed in 1 patient. All 3 patients elected to undergo radical nephrectomy. Mean time from cryosurgery to nephrectomy was 275 days. The cryoablated lesions demonstrated coagulative necrosis as evidenced by numerous histiocytes, cholesterol crystals and dystrophic calcification. There was no evidence of viable tumor within the cryoablated field. CONCLUSIONS: The longer term tumoricidal effects of laparoscopic renal cryosurgery in human renal tissue have been demonstrated. However, careful patient selection with lesions less than 3.0 cm and vigilant monitoring of the iceball under strict radiographic guidance are imperative to ensure successful oncological outcomes.

Aged↗

PubMed2005

Holmium laser enucleation of the prostate for men with urinary retention.

PURPOSE: Holmium laser enucleation of the prostate (HoLEP) is an established procedure for the treatment of patients with benign prostatic hyperplasia. We performed a study to examine a group of patients in urinary retention treated by HoLEP. MATERIALS AND METHODS: A retrospective analysis of 164 consecutive patients with urinary retention who underwent HoLEP between January 2000 and August 2004 was performed. RESULTS: Mean patient age was 72.1 years (range 34 to 95). Mean duration of urinary retention was 28.9 days (range 2 to 365). Mean preoperative transrectal ultrasound measured prostate volume was 107.1 cc (range 5 to 242). Mean weight of resected tissue was 81.9 grams (range 2.5 to 271). Mean duration of postoperative catheterization and hospitalization was 22.5 hours (range 2 to 240) and 33.7 hours (range 2 to 144), respectively. All patients were able to void following treatment and remain catheter free. CONCLUSIONS: HoLEP is an effective treatment, with low morbidity, for patients with urinary retention. These results suggest that HoLEP may be the ideal treatment for men with urinary retention due to benign prostatic obstruction.

Adult↗

PubMed2005

Cystine: helical computerized tomography characterization of rough and smooth calculi in vitro.

PURPOSE: The classification of cystine stones into rough and smooth varieties has been suggested as an aid to choosing treatment for these difficult stones. Since the surface of stones is difficult to visualize preoperatively, we tested the hypothesis that the surface morphology of cystine stones correlates with their internal structure, as viewed by helical computerized tomography (CT). MATERIALS AND METHODS: Cystine stones were examined visually and categorized into rough (15 stones) and smooth (16 stones) subpopulations of similar size. Each stone was scanned in a helical CT scanner (GE Quad Scanner) to assess radiological characteristics and to measure attenuation values. Scans were also performed using a microCT 20 high resolution laboratory scanner (Scanco Medical AG, Bassersdorf, Switzerland) at 34 microm voxel size and the percent of internal voids was determined. RESULTS: Mean helical CT attenuation values +/- SD for rough stones were lower than for smooth stones (702 +/- 206 vs 921 +/- 51 HU, p <0.002) and the radiological appearance of rough stones suggested radiolucent voids. Internal voids in rough stones were confirmed using micro CT. Rough cystine stones contained a higher percent of internal voids (0.30% vs 0.06%, p <0.0001). CONCLUSIONS: Rough cystine stones can be distinguished from smooth stones using helical CT in vitro, suggesting that it may be possible to distinguish these stones preoperatively. Since rough cystine stones have been reported to be susceptible to shock wave lithotripsy, the identification of this morphology of cystine stones in the patient using attenuation values and appearance on helical CT could be valuable for planning treatment.

Cysteine↗