Interfaces between Cranial Bone and AISI 304 Steel after Long-Term Implantation: A Case Study of Cranial Screws.

Interfaces between AISI 304 stainless steel screws and cranial bone were investigated after long-term implantation lasting for 42 years. Samples containing the interface regions were analyzed using state-of-the-art analytical techniques including secondary ion mass, Fourier-transform infrared, Raman, and X-ray photoelectron spectroscopies. Local samples for scanning transmission electron microscopy were cut from the interface regions using the focused ion beam technique. A chemical composition across the interface was recorded in length scales covering micrometric and nanometric resolutions and relevant differences were found between peri-implant and the distant cranial bone, indicating generally younger bone tissue in the peri-implant area. Furthermore, the energy dispersive spectroscopy revealed an 80 nm thick steel surface layer enriched by oxygen suggesting that the AISI 304 material undergoes a corrosion attack. The attack is associated with transport of metallic ions, namely, ferrous and ferric iron, into the bone layer adjacent to the implant. The results comply with an anticipated interplay between released iron ions and osteoclast proliferation. The interplay gives rise to an autocatalytic process in which the iron ions stimulate the osteoclast activity while a formation of fresh bone resorption sites boosts the corrosion process through interactions between acidic osteoclast extracellular compartments and the implant surface. The autocatalytic process thus may account for an accelerated turnover of the peri-implant bone.

PVDF Fibers Modification by Nitrate Salts Doping.

The method of inclusion of various additives into a polymer depends highly on the material in question and the desired effect. In the case of this paper, nitride salts were introduced into polyvinylidene fluoride fibers prepared by electrospinning. The resulting changes in the structural, chemical and electrical properties of the samples were observed and compared using SEM-EDX, DSC, XPS, FTIR, Raman spectroscopy and electrical measurements. The observed results displayed a grouping of parameters by electronegativity and possibly the molecular mass of the additive salts. We virtually demonstrated elimination of the presence of the γ-phase by addition of Mg(NO3)2, Ca(NO3)2, and Zn(NO3)2 salts. The trend of electrical properties to follow the electronegativity of the nitrate salt cation is demonstrated. The performed measurements of nitrate salt inclusions into PVDF offer a new insight into effects of previously unstudied structures of PVDF composites, opening new potential possibilities of crystalline phase control of the composite and use in further research and component design.

Structural Factors Inducing Cracking of Brass Fittings.

Cu-Zn-Pb brasses are popular materials, from which numerous industrially and commercially used components are fabricated. These alloys are typically subjected to multiple-step processing-involving casting, extrusion, hot forming, and machining-which can introduce various defects to the final product. The present study focuses on the detailed characterization of the structure of a brass fitting-i.e., a pre-shaped medical gas valve, produced by hot die forging-and attempts to assess the factors beyond local cracking occurring during processing. The analyses involved characterization of plastic flow via optical microscopy, and investigations of the phenomena in the vicinity of the crack, for which we used scanning and transmission electron microscopy. Numerical simulation was implemented not only to characterize the plastic flow more in detail, but primarily to investigate the probability of the occurrence of cracking based on the presence of stress. Last, but not least, microhardness in specific locations of the fitting were examined. The results reveal that the cracking occurring in the location with the highest probability of the occurrence of defects was most likely induced by differences in the chemical composition; the location the crack in which developed exhibited local changes not only in chemical composition-which manifested as the presence of brittle precipitates-but also in beta phase depletion. Moreover, as a result of the presence of oxidic precipitates and the hard and brittle alpha phase, the vicinity of the crack exhibited an increase in microhardness, which contributed to local brittleness.

Fundamental Improvement of Creep Resistance of New-Generation Nano-Oxide Strengthened Alloys via Hot Rotary Swaging Consolidation.

New-generation oxide dispersion-strengthened (ODS) alloys with a high volume fraction of nano-oxides of 5% are intended to become the leading creep- and oxidation-resistant alloys for applications at 1100-1300 °C. Hot consolidation of mechanically alloyed powders by intensive plastic deformation followed by heat treatment of the alloys are the key aspects for achieving top creep properties, typically ensured by a coarse-grained microstructure strengthened with homogeneously dispersed, very stable yttrium nano-oxides. The rotary swaging method proves to be favourable for hot consolidation of the new-generation ODS alloy presented. Compared to specimens consolidated by hot rolling, consolidation by hot rotary swaging predetermines the formation of coarse grains with a very high aspect ratio during subsequent secondary recrystallization. Such a grain morphology increases the creep strength of the new-generation ODS alloy considerably.

Effect of Ni ion release on the cells in contact with NiTi alloys.

Nickel-titanium alloys have been used in medical applications for several years; however, biocompatibility of the material remains controversial. In the present study, the human umbilical vein endothelial cells (HUVEC) were cultured in contact with the nitinol used in two different heat treatment  surface modifications-helium and hydrogen. The amount of Ni ions released from these alloys in contact with HUVEC was measured in media and in the cells by ICP-MS. An increased release of Ni ions was detected in He alloy compared with H2 alloy modification with an elevation with the metal exposition duration (24 h vs. 72 h). The cells contained the Ni ions in both selected alloy modifications with the lower levels in H2 alloys. To evaluate the potential of multiple metal applications, similar values were observed in media and in cell suspension for all surface modification combinations. The model analysis of effect of metal ion release on distant cells in the body showed that the concentration is interestingly similar to concentrations in cells in direct contact with the metal alloy. The cells are able to regulate the concentration of Ni ions within the cell. According to our best knowledge, the study for the first time describes the presence of Ni ions released from nitinol directly in the cells. In the case of the H2 modification, the lowest levels of Ni ions were detected both in medium and in the cells, which likely increases the biocompatibility of the nitinol alloy.

Osteoarthritic process modifies expression response to NiTi alloy presence.

Nickel-titanium alloy (nitinol, NiTi) is a biomaterial with unique thermal shape memory, superelasticity and high damping properties. Therefore NiTi has been used in medical applications. In this in vitro study, the effect of NiTi alloy (with two surface modifications - helium and hydrogen) on gene expression profile of selected interleukins (IL-1ß, IL-6 and IL-8) and matrix metalloproteinases (MMP-1 and MMP-2) in human physiological osteoblasts and human osteoarthritic osteoblasts was examined to respond to a question of the different behavior of bone tissue in the implantation of metallic materials in the presence of cells affected by the osteoarthritic process. The cells were cultivated in contact with NiTi and with or without LPS (bacterial lipolysaccharide). Changes in expression of target genes were calculated by 2-ΔΔCt method. An increased gene expression of IL-1ß in osteoarthritic osteoblasts, with even higher expression in cells collected directly from the metal surface was observed. In case of physiological osteoblasts, the change in expression was detected after LPS treatment in cells surrounding the disc. Higher expression levels of IL-8 were observed in osteoarthritic osteoblasts after NiTi treatment in contact with alloy, and in physiological osteoblasts without relation to location in combination of NiTi and LPS. IL-6 was slightly increased in physiological osteoblastes after application of LPS. MMP-1 expression level was obviously significantly higher in osteoarthritic osteoblasts with differences regarding the metal surface and location. MMP-2 expression was decreased in both cell lines after LPS treatment. In conclusion, results of present study show that the NiTi alloy and the treatment by LPS, especially repeated doses of LPS, change the gene expression of selected ILs and MMPs in human osteoblast cell cultures. Some of the changes were depicted solely to osteoarthritic osteoblasts.

Multi-institutional experience with PIC cystography--incidence of occult vesicoureteral reflux in children with febrile urinary tract infections.

OBJECTIVES: It has been reported that all children with febrile urinary tract infections (FUTIs) and normal voiding cystourethrogram (VCUG) findings show occult reflux (vesicoureteral reflux [VUR]) when examined by cystography performed with positioning of the instillation of contrast at the ureteral orifice (PIC cystography). In this study, we evaluated the reproducibility of this finding using a prospective multi-institutional collaborative examination to determine whether PIC-VUR is as common in such cases as previously shown. METHODS: From March 2002 to October 2003, four institutions performed PIC cystography consecutively and prospectively in pediatric cases of FUTI (greater than 101 degrees F) who had not shown VUR by conventional VCUG. We correlated the ureteral orifice (UO) configuration and position with the status of PIC-VUR. RESULTS: PIC cystography was performed in 39 children (31 girls and 8 boys; 75 FUTIs). We identified PIC-VUR in 32 (82%) of 39 children, involving 58 (74%) of 78 ureters. The likelihood of demonstrating PIC-VUR was increased 37-fold if the UO showed a patulous configuration and was increased 9-fold if the UO showed a lateral configuration. PIC-VUR was noted uniformly in UOs showing hydrodistension. CONCLUSIONS: This multi-institutional registry showed that the incidence of PIC-VUR (82%) in children with FUTI and normal standard VCUG findings is similar to that previously reported. We consider that PIC-VUR likely accounts for the FUTIs.

Dysfunctional elimination syndrome as an etiology of idiopathic urethritis in childhood.

PURPOSE: Idiopathic urethritis (IU) of childhood or urethrorrhagia is a common problem characterized by blood spotting in the underwear between voiding. A clear etiology has not been established and treatments vary. We postulate that idiopathic urethritis is a manifestation of underlying dysfunctional elimination syndrome (DES). MATERIALS AND METHODS: During a 5-year period we reviewed the records of all children diagnosed with IU in our practice. In total 72 children fit the analysis criteria. There were 68 boys and 4 girls. All children presented with either gross blood per urethra or microhematuria. Children with active infection, immunodeficiency, neurogenic bladder, vesicoureteral reflux, infravesical obstruction, urethral trauma or other genitourinary anomalies were excluded. Evaluation included thorough history and physical examination, urinalysis and urine culture. Renal and bladder ultrasound, voiding cystourethrogram and uroflow/electromyogram/post-void residual volume were obtained in select patients. Study children were divided into 2 cohorts. The first cohort (group 1, 37 patients) was treated with traditional remedies using antibiotics, urinary analgesics and/or anticholinergics. The second cohort (group 2, 35 patients) was treated by bowel and bladder regimens, laxatives when necessary, and biofeedback and/or alpha-blockers when sphincter dyssynergia was identified. RESULTS: A total of 13 patients in group 1 (35%) had a full response to treatment, 6 (16%) had a partial response and 18 (49%) failed to respond. A total of 29 patients in group 2 (83%) had a full response to treatment, 2 (6%) had a partial response and 4 (11%) had no response. It took an average of 12.1 months to respond fully in group 1, while in group 2 the same full response took an average of 5.2 months. Of the 18 children who crossed over from group 1 to group 2, 15 (83%) had a full response with an average response time of 7.3 months. CONCLUSIONS: Our data clearly reveal a higher cure rate when children with urethritis are treated according to DES guidelines. IU of childhood is a manifestation of underlying DES and should be treated as such.

Results of 265 consecutive proximal hypospadias repairs using the Thiersch-Duplay principle.

PURPOSE: We review the evolution of the concept of tubularization of the urethral plate and our results in the repair of proximal hypospadias. MATERIALS AND METHODS: A total of 281 children born with proximal hypospadias underwent Thiersch-Duplay urethroplasty with or without a midline incision of the urethral plate between 1989 and 1998. Followup data were available in 265 children. RESULTS: Excellent functional and cosmetic results were achieved in 88.7% of the patients. The use of either a dartos or tunica vaginalis flap to waterproof the urethral suture line resulted in a decrease in the fistula rate from 17% to 1.8%. CONCLUSIONS: The principles of Thiersch-Duplay urethroplasty represent the basic foundation for surgical techniques that use the urethral plate to construct a urethral tube. The use of this principle in the repair of proximal hypospadias compares favorably with other methods.

Prevention of renal fibrosis by spironolactone in mice with complete unilateral ureteral obstruction.

PURPOSE: Recent data suggest that aldosterone directly mediates cardiac fibrosis and hypertensive nephrosclerosis. We conducted experiments to determine whether administration of spironolactone, a mineralocorticoid receptor antagonist, reduced renal fibrosis in an experimental model of obstructive uropathy. MATERIALS AND METHODS: Complete unilateral ureteral obstruction (UUO) was created surgically in 8 to 10-week-old male C57BL/6 mice by placing sutures around the right ureter. Spironolactone (50 mg/kg/daily) or 1% dimethyl sulfoxide vehicle was administered by subcutaneous injection for 1 to 2 weeks, and renal fibrosis was assessed by measuring trichrome staining and type I collagen deposition in the kidney. RESULTS: UUO lasting 1 week was associated with minimal parenchymal damage and spironolactone had no demonstrable effect. In contrast, administration of the mineralocorticoid antagonist (8 mice) for a 2-week period significantly reduced renal fibrosis in the obstructed kidney, compared to mice given the dimethyl sulfoxide vehicle (9). The beneficial effect of spironolactone treatment was not associated with any changes in serum potassium or aldosterone concentration, or urinary concentrations of sodium or potassium. CONCLUSIONS: Administration of spironolactone reduced renal fibrosis in mice with UUO. These findings suggest that clinical trials are warranted to determine the efficacy of aldosterone antagonists in conjunction with angiotensin converting enzyme inhibitors and/or angiotensin receptor blockers as renoprotective agents in patients with obstructive uropathy.

Infectious response to E. coli: molecular and genetic pathways.

Urinary tract infections are most commonly caused by type 1-piliated Escherichia coli (UPEC) and result in urothelial apoptosis, local cytokine release and neutrophil infiltration. A human urothelial cell line was incubated with various E. coli isolates and was then characterized by flow cytometry. UPEC induced rapid urothelial apoptosis that was dependent upon interactions mediated by type 1 pili. Laboratory isolates expressing type 1 pili-induced approximately 50% less apoptosis. UPEC blocked activity of a NF-kappaB-dependent reporter in response to inflammatory stimuli by stabilizing IkappaBalpha and UPEC rapidly altered cellular signalling pathways. Finally, blocking NF-kappaB activity increased the level of the laboratory strain-induced apoptosis to the level of apoptosis induced by UPEC. These results suggest that UPEC blocks NF-kappaB and enhances type 1 pili-induced apoptosis as a component of the uropathogenic programme.

Efficacy and safety of the Healthtronics LithoTron lithotripter.

PURPOSE: To evaluate our experience with the LithoTron lithotripter (Healthtronics, Atlanta, GA), a dry portable system that utilizes a spark-gap electrode as an energy source. PATIENTS AND METHODS: We prospectively evaluated the first 312 treatments performed on 199 men and 99 women with an average age of 43.5 years (range 4 months-80 years), over a 25-month period between May 1999 and June 2001. Of the 468 stones treated, 136 were located in the ureter, 52 in the renal pelvis or ureteropelvic junction, and 230 in the kidney; the sites of 50 were not specified in our database. The average stone size was 8.0 mm (range 1-40 mm). Follow-up included a plain (KUB) film, CT scan, or intravenous urogram (IVU) and was available for 256 patients. "Stone free" was defined as no fragments visible on postoperative images. The mean radiographic follow-up was 74 days (range 0-866 days). Data collection was initially done manually by data sheets, but a Web-based medical database application was developed in order to enter, store, retrieve, and analyze the data more efficiently. RESULTS: The average number of shocks delivered per renal unit was 2689 at 25.8 kV. Seventy-five percent of the procedures were performed with intravenous sedation. Two thirds (169/256) of the patients were rendered stone free with one treatment. According to size, 71% (209/294) of stones <1 cm, 57% (39/68) of stones between 1.0 and 1.5 cm, and 22% (8/36) of stones >1.5 cm were eliminated. There were 23 patients who required further treatment; from the available data, 18 of them are currently stone free. Perioperative complications occurred in 6 patients (2%). No patient had worsening renal function or new-onset hypertension. The effectiveness quotient was 59.3%. CONCLUSION: The LithoTron lithotripter is satisfactory for stones <1 cm.

Single layered small intestinal submucosa in the repair of severe chordee and complicated hypospadias.

PURPOSE: Severe ventral chordee often accompanies proximal hypospadias. We describe our experience with single layered small intestinal submucosa (SIS), a commercially available, acellular, collagen based biomaterial, in the repair of severe chordee as part of a multistage approach to the repair of proximal hypospadias. MATERIALS AND METHODS: Between 2001 and 2002, 9 boys with proximal hypospadias (penoscrotal to perineal) and severe ventral chordee (greater than 40 degrees) underwent SIS grafting to correct the curvature. In each case the urethral plate was transected at the point of maximal curvature, the defect in the corporal bodies was measured, and the SIS graft was cut 2 mm wider around the perimeter of the defect and sutured into place. Skin resurfacing of the ventral penis was performed in standard fashion using Byars flaps. Recurrence of chordee was assessed by an artificial penile erection test at the time of stage 2 reconstruction. RESULTS: Of the 9 boys 8 underwent a planned 2-stage repair with subsequent urethroplasty 6 to 12 months after the initial stage 1 chordee repair. Median age at stage 1 repair of the 8 boys was 9 months. Native meatus location was penoscrotal in 6 boys, mid scrotal in 1 and perineal in 1. A 14 month-old boy underwent 1-stage chordee correction with SIS and a transverse preputial island tube graft urethroplasty for penoscrotal hypospadias. There were no perioperative medical or surgical complications related to use of SIS for chordee repair. Median age of the 8 boys at stage 2 repair was 18 months. At stage 2 the graft site was supple and smooth without significant scarring. All chordee correction has remained durable with followup ranging from 16 to 21 months. Postoperative complications occurred in 3 cases, including meatal stenosis requiring meatoplasty, subcoronal fistula requiring repair and complete breakdown of the neourethra in the single stage repair case. CONCLUSIONS: Although this study includes a small population of patients and has limited followup, our favorable experience with single layer SIS suggests that it is a safe and effective, commercially available material for corporal body grafting to correct severe chordee as part of a multistage surgical approach to repair complex hypospadias. A larger series of patients with longer followup is necessary to determine if the chordee correction remains durable. Our experience is insufficient to judge its efficacy in single stage repairs.

Chylous ascites following surgical treatment for wilms tumor.

PURPOSE: Postoperative chylous ascites is a rare complication of retroperitoneal surgery that has considerable morbidity. We review the pathogenesis and management of chylous ascites following surgical treatment of Wilms tumor. MATERIALS AND METHODS: We identified 9 children with chylous ascites after surgical treatment of Wilms tumor. Of these cases 3 were treated at a single institution during the last 20 years and 6 were identified during retrospective chart reviews of patients enrolled in National Wilms Tumor Studies 3 and 4 to identify surgical complications. Chylous ascites presented as increased abdominal girth and poor feeding. Paracentesis or laparotomy was diagnostic. RESULTS: Patient age at presentation with Wilms tumor ranged from 6 to 95 months (median 15). Left nephrectomy was performed in 5 cases, right nephrectomy in 3, and left nephrectomy and partial right nephrectomy in 1 with bilateral disease. Lymphadenectomy including the hilar and periaortic lymph nodes was performed in 5 patients, 4 of whom also underwent some form of suprahilar lymph node dissection. Three patients underwent lymph node sampling of the hilar, periaortic and some suprahilar lymph nodes. All children received adjuvant chemotherapy and 4 were treated with adjuvant irradiation to the surgical bed before the diagnosis of chylous ascites. The interval between surgery and diagnosis of ascites ranged from 12 to 49 days (median 21). Of the patients 7 were successfully treated with conservative measures, total parenteral nutrition and/or a diet containing primarily medium chain triglycerides, and 2 required invasive procedures, including exploratory laparotomy and ligation of disrupted lymphatic vessels or placement of a peritoneovenous shunt. CONCLUSIONS: Extensive lymph node dissection, particularly above the level of the renal hilum, appears to be associated with the development of postoperative chylous ascites. The National Wilms Tumor Study guidelines do not require formal lymph node dissection for staging and only lymph node sampling is recommended. Elimination of formal lymphadenectomy along with meticulous ligation of lymphatics should decrease the incidence of this complication. Fortunately, conservative treatment with total parenteral nutrition and/or medium chain triglycerides will remedy the problem in the majority of children.

The role of gadolinium enhanced magnetic resonance imaging for children with suspected acute pyelonephritis.

PURPOSE: The diagnosis of pyelonephritis is primarily clinical. However, the history and physical findings can be confusing in children, leading to adjunctive nuclear renal cortical scintigraphic studies (99mtechnetium dimercapto-succinic acid [DMSA]) to confirm the diagnosis. Nonetheless, ambiguity occurs when differentiating between acute pyelonephritis and chronic scarring. We report our initial experience with gadolinium enhanced inversion recovery magnetic resonance imaging (MRI) to diagnose acute pyelonephritis. MATERIALS AND METHODS: Nine patients 7 months to 18 years old (mean age 81 months) underwent MRI to confirm radiographically a clinical suspicion of acute pyelonephritis. All patients had at least 1 prior episode of clinical pyelonephritis. Data were collected to determine whether acute pyelonephritic changes could be differentiated from chronic pyelonephritis on the basis of MRI characteristics. RESULTS: Of the 9 patients 4 were identified as having acute pyelonephritis on MRI (persistently high signal intensity after gadolinium), 2 demonstrated evidence of postpyelonephritic scar (parenchymal loss without change in signal intensity), 1 had evidence of acute pyelonephritis and chronic changes, and 2 had a completely normal examination (decreased signal intensity after gadolinium). At our institution the billable cost of MRI to the patient is $1,329, while the billable cost of 99mtechnetium DMSA is $1,459. All patients younger than 6 years required intravenous sedation for MRI, whereas 70% of those younger than 6 years require intravenous sedation for DMSA scanning at our institution. MRI provided greater anatomical detail regarding the renal architecture without radiation exposure, and allowed the unambiguous diagnosis of acute versus chronic pyelonephritis scar in a 1-time (versus often multipart for DMSA) imaging study. CONCLUSIONS: In cases where adjunctive imaging studies are useful to make a diagnosis gadolinium enhanced inversion recovery magnetic resonance imaging allows the detection of acute pyelonephritis rapidly, cost-effectively and safely in the pediatric population.

Modified cecal flap neoappendix for the Malone antegrade continence enema procedure: a novel technique.

PURPOSE: We report our experience with the creation of a tubularized cecal flap to construct a neoappendix. This flap effectively serves as an alternative means of creating a conduit for antegrade continence enemas in patients who have either an absent or an unusable appendix. MATERIALS AND METHODS: We reviewed our results from our initial 4 patients in whom we used this technique. A neoappendix is created from a medially based flap of distal cecum that is tubularized over a catheter and then buried in a seromuscular tunnel to create an antireflux mechanism. A skin stoma is then created. RESULTS: All stomas are continent, functional and without any evidence of stenosis or necrosis of the cecal flap with followup ranging from 3 months to 8 years. CONCLUSIONS: A medially based cecal flap neoappendix is an easily created and reliable conduit for antegrade enemas. This procedure should be considered within the surgical armamentarium of urologists and pediatric surgeons when the appendix is absent, atretic or fibrotic.

Bladder function associated with posterior urethral valves after primary valve ablation or proximal urinary diversion in children and adolescents.

PURPOSE: We retrospectively reviewed 2 series of patients with posterior urethral valves treated initially with valve ablation preceded by bilateral cutaneous ureterostomies or valve ablation alone to evaluate and compare bladder function behavior of each treatment group. MATERIALS AND METHODS: From 1970 to 1983, 19 males 22 days to 21 months old with posterior urethral valves were treated with 1 of 2 initial surgical approaches, including upper tract diversion, delayed undiversion and ablation in 11 (group 1), and primary valve ablation only in 8 (group 2). Median patient age at the time of cutaneous urinary diversion and primary valve ablation for groups 1 and 2 was 7 and 9 months, respectively. Median duration of bladder defunctionalization was 48 months. All patients were evaluated urodynamically after initial ablation or re-functionalization of the bladder using standard rapid fill cystometry. Median patient age for groups 1 and 2 was 14 and 9.5 years, respectively, at the time of urodynamic testing 16 and 12.6 years, respectively, at followup. RESULTS: Urodynamic assessment revealed detrusor instability in 5 group 1 patients but in only group 2 1 patient. Group 2 patients had significantly lower median end filling pressure (4 versus 15 cm. water, p <0.03) and higher maximum bladder capacity (1.4 versus 0.8, p <0.005) than those in group 1. Group 1 patients had lower compliance than those in group 2 (median 15 versus 82 cm. water, p <0.05). Further analysis showed no difference between groups 1 and 2 in overall median voiding detrusor pressure at maximum flow (51 versus 52.6 cm. water, respectively). Cystometric detrusor under activity patterns were noted in 5 group 1 and 2 group 2 patients. Residual urine volumes were 17%, 31%, 19% and 8% of bladder capacity, respectively, in 2 group 1 and 2 group 2 patients. At final followup 5 group 1 and 2 group 2 patients had renal function deterioration. Two other group 1 patients and group 2 had progression to end stage renal failure. A higher ureteral reimplantation rate was noted in group 1 (63%) than group 2 (6%). CONCLUSIONS: This retrospective study revealed that long-term bladder function of patients with posterior urethral valves treated with temporary supravesical diversion is affected more adversely than those treated with valve ablation alone.

Percutaneous hepatolithotomy: the Northwestern University experience.

Obstruction of intrahepatic ducts by calculi can lead to abdominal pain, cholestasis, abscesses, and cholangitis. Patients with stones recalcitrant to extraction using endoscopic retrograde cholangiopancreatography (ERCP) have traditionally been referred to a general surgeon for open stone extraction or hepatic lobectomy despite its great potential morbidity. Borrowing techniques, instrumentation, and experience in performing percutaneous nephrolithotomy, we describe our experience with percutaneous hepatolithotomy (PHL), a minimally invasive, safe, and effective alternative to open surgery for recalcitrant biliary stones.