Showing papers on "Kidney surgery published in 2005"

Glucose metabolism in renal transplant recipients: effect of calcineurin inhibitor withdrawal and conversion to sirolimus.

Abstract: Cyclosporine A (CsA) and tacrolimus have been associated with an increased risk for diabetes after transplantation, whereas sirolimus is deemed to be devoid of any effect on glucose metabolism. This study was performed to investigate the effect of the withdrawal of calcineurin inhibitors and the switch to sirolimus on peripheral insulin resistance and pancreatic beta cell response. Twenty-six patients who received a kidney transplant and discontinued CsA and were converted to sirolimus and 15 recipients of suboptimal kidneys who were treated with tacrolimus plus sirolimus for the first 3 mo after grafting and thereafter with sirolimus alone were enrolled. All patients underwent an oral glucose tolerance test and intravenous insulin tolerance test before and 6 mo after the conversion to sirolimus-alone therapy. The withdrawal of CsA or tacrolimus was associated with a significant fall of insulin sensitivity (both P = 0.01) and with a defect in the compensatory beta cell response, as measured by the disposition index (P = 0.004 and P = 0.02, respectively). The increase of insulin resistance and the decrease of disposition index significantly correlated with the change of serum triglyceride concentration after the conversion to sirolimus-based therapy (R(2) = 0.30, P = 0.0002; and R(2) = 0.19, P = 0.004, respectively). Clinically, the switch to sirolimus was associated with a 30% increase of incidence of impaired glucose tolerance and with four patients' developing new-onset diabetes. In conclusion, the discontinuation of calcineurin inhibitors and their replacement by sirolimus fail to ameliorate the glycometabolic profile of kidney transplant recipients. Rather, it is associated with a worsening of insulin resistance and an inappropriately low insulin response.

Development of an ectopic site for islet transplantation, using biodegradable scaffolds.

Abstract: Clinical islet transplantation in liver has achieved normoglycemia. However, this site may not be ideal for islet survival. To create a more optimal site for islet transplantation, we have developed a construct with biodegradable scaffolds. Islets were seeded in scaffolds and transplanted into the epididymal fat pad of diabetic BALB/c mice. Controls included islets transplanted underneath the kidney capsule or into the fat pad without scaffolds. All animals with islets in scaffolds or the kidney became normoglycemic and maintained this metabolic state. When islets were transplanted without scaffolds the time to achieve normoglycemia was significantly increased and less than 45% of mice survived. An oral glucose tolerance test was performed on the scaffold and kidney groups with similar blood glucose levels and area under the curve values between the groups. Grafts were removed at more than 100 days posttransplantation and all animals became hyperglycemic. There was no significant difference in insulin content between the grafts and all grafts were well vascularized with insulin-positive beta cells. Therefore, islets in scaffolds function and restore diabetic animals to normoglycemic levels, similar to islets transplanted underneath the kidney capsule, suggesting scaffolds can be used to create a site for islet transplantation.

Design and Application of Compliant Mechanisms for Surgical Tools

Abstract: This paper introduces the benefits of exploiting elasticity in the engineering design of surgical tools, in general, and of minimally invasive procedures, in particular. Compliant mechanisms are jointless mechanisms that rely on elastic deformation to transmit forces and motion. The lack of traditional joints in these single-piece flexible structures offers many benefits, including the absence of wear debris, pinch points, crevices, and lubrication. Such systems are particularly amenable to embedded sensing for haptic feedback and embedded actuation with active-material actuators. The paper provides an overview of design synthesis methods developed at the Compliant Systems Design Laboratory and focuses specifically on surgical applications. Compliant systems have potential to integrate. well within the constraints of laparoscopic procedures and telerobotic surgery. A load-path representation is used within a genetic algorithm to solve two gripper example problems. In addition, the paper illustrates the design and construction of an organ (kidney) manipulator for use in minimally invasive procedures.

Main and accessory renal arteries--a morphological study.

Abstract: The present work was undertaken to document the incidence of accessory renal arteries in kidney specimens obtained from subjects of Indian origin. Comprehensive dissection carried out in the dissection hall of Anatomy Department of All India Institute of Medical Sciences (India) on forty cadavers over a period of five years revealed a single main renal artery on either side in 80% of the specimens. The mean length of the main renal artery was 31.05 +/- 12 and 25.0 +/- 9.5 mm on the right and the left side respectively. Multiple (accessory) renal arteries were observed in 20% of the specimens with unilateral anomaly (15%) being more commonly encountered than bilateral anomaly (5%). The mean length of the accessory renal artery was 36.4 +/- 10 and 36.6 +/- 11 mm on the right and the left side respectively. The accessory artery when present, invariably crossed the anterior aspect of the ureter. Familiarity about the possible variations in the renal arterial pattern are especially important for the personnel dealing with kidney retrieval and transplantation, various endourologic procedures and innumerable interventional techniques. In the majority of such situations, it is the comprehensive knowledge of the renal arterial pattern which remains the key issue in determining the technical feasibility of surgical interventions as well as the post operative management.

Older living donors provide excellent quality kidneys: a single center experience (older living donors)

Abstract: Background: The role of advanced age live donors remains controversial because of decline in glomerular filtration rate and perceived increased risks of perioperative complications. Methods: A retrospective review of all live donor transplants performed from January 2000 to December 2003. Results: Seventy-eight live donor transplants were performed during the period of review, 47 (60.3%) female and 31 (39.7%) male. Twenty-two (28.2%) of the donors were >50 yr old, 15 (68%) female and seven (32%) male. Living related donation was performed in 56 (74.4%) and unrelated in 20 (35.6%). Laparoscopic nephrectomy was performed in 29 (37.2%) and open nephrectomy in 49 (62.8%). More donors >50 underwent laparoscopic nephrectomy, 13 of 22 (59.1%) vs. 16 of 56 (28.6%). Overall patient and graft survival at 1 yr are 97 and 97%. One-year patient and graft survival is 100% vs. 96% and 100% vs. 96% in the older vs. young donors. Rejection occurred in nine of 78 (11.5%), but was not different between groups. Older donors had a reduced creatinine clearance 107.5 ± 3.4 vs. 124.2 ± 3.1 mL/min (p = 0.002) and a reduced clearance normalized for body surface area 60.6 ± 3.6 mL/(min m2) vs. 70.2 ± 2.6 mL/(min m2) (p = 0.045). Recipient serum creatinine was higher on postoperative day 1 in the older donor group 5.4 mg/dL vs. 4.4 mg/dL (p = 0.009). There was no difference in recipient serum creatinine at postoperative day 7, 30, 90, 180, 365 and 730. Donor serum creatinine was not different between groups on postoperative days 1, 7 and 30 but was higher in group 1 vs. group 2 on postoperative day 365, 1.26 ± 0.26 mg/dL vs. 1.01 ± 0.18 mg/dL (p = 0.020). Conclusions: Despite a reduced initial creatinine clearance, renal function is comparable in recipients of both young and old donor kidneys. Older donors had a slightly reduced serum creatinine 1 yr post-donation that warrants additional follow-up to determine if the observations continue. The introduction of laparoscopic nephrectomy may provide additional incentive for older donors to present for live donor nephrectomy.

Analysis of thermal stress in cryosurgery of kidneys.

Abstract: In this study, the thermal stress distribution in cryosurgery of kidney was investigated using a multiphysics finite element model developed in ANSYS (V8.1). The thermal portion of the model was verified using experimental data and the mechanics portion of the model (elastic) was verified using classic analytical solutions. Temperature dependent thermal and mechanical properties were used in the model. Moreover, the model accounts for thermal expansion due to both thermal expansion in single phase and volumetric expansion associated with phase change of tissue water to ice. For a clinical cylindrical cryoprobe inserted into the renal cortex from the top-middle renal capsule, it was found that the thermal stress distributions along the radial position are very different at different depths from the top renal capsule. The thermal stress is much higher at both ends than in the middle of the cryoprobe surface. It was found that there might be more tissue next to the top renal capsule than other region undergoing microcrack formation or plastic deformation. Furthermore, it was found that macrocrack formation is more likely to occur in tissue adjacent to the cryoprobe surface (especially on the sharp point tip) and during the thawing phase of cryosurgery. It was further found that the volumetric expansion associated with phase change induced much higher thermal stress than thermal expansion in a single phase and might therefore be the main cause of the frequently observed crack formation shortly after initiation of thawing in cryosurgery. Because the thermal stress adjacent to the cryoprobe is much higher than the yield stress of frozen renal tissue, a plastic stress model is required for better modeling of the thermal stress distribution in cryosurgery of kidney in future. However the computational effort will then be drastically increased due to the strong nonlinear nature of the plastic model and more experimental studies are indispensable for better understanding of the mechanical behavior of frozen tissue in cryosurgery.

The sensitivity of antenatal ultrasound for predicting renal tract surgery in early childhood

Abstract: Objective To establish the sensitivity of antenatal ultrasound for identifying the need for renal tract surgery in infancy and early childhood. Methods A retrospective analysis of the surgical records in children under 5 years of age undergoing renal tract surgery in a regional pediatric urological surgery referral unit was carried out. All records between May 1997 and July 2002 were examined to assess the relationship between prenatal ultrasound findings and postnatal surgical pathology. Results A total of 106 operations had been performed. The detection rate of multicystic renal dysplasia was 100% (17/17). The equivalent detection rates for pelviureteral junction obstruction, duplex renal system and vesicoureteral reflux were 82.8, 67 and 26.1%, respectively. None of the babies with renal tumors had abnormal antenatal ultrasound findings. The diagnosis of postnatal renal surgical pathology was made on the basis of prenatal scan findings in 59.6% of cases, while recurrent urinary tract infection led to the diagnosis in 26.0%. Conclusions Approximately 40% of children requiring surgery for renal tract pathology will have a normal antenatal ultrasound examination. The prevalence of abnormal antenatal ultrasound findings varies depending on the type of renal tract pathology. Despite these findings, the commonest indicator for surgery remains abnormal prenatal scan findings, followed by recurrent urinary tract infections. Copyright  2005 ISUOG. Published by John Wiley & Sons, Ltd.

Evaluation of the effects of nephrotomy on renal function in clinically normal cats

Abstract: Objective—To evaluate the effects of nephrotomy on renal function in clinically normal cats. Animals—20 specific-pathogen-free, 9- to 11-month old female mixed-breed cats. Procedure—Serum chemistry analyses, CBC determinations, urinalyses, microbiologic urine cultures, renal ultrasonography, abdominal radiography, and single-kidney and total glomerular filtration rate (GFR) determinations by use of renal scintigraphy and measurements of plasma disappearance of technetium 99m-diethylenetriaminepentaacetic acid were performed before surgery and at 3, 12, 26, 52, and 78 weeks after surgery in 10 cats that underwent unilateral nephrotomy and in 10 control cats that underwent a sham surgical procedure. Results—Two cats (1 from each group) did not complete the study, and their data were eliminated from analyses. Unilateral nephrotomy resulted in a 10% to 20% reduction in mean single-kidney GFR, compared with that of nephrotomy contralateral control kidneys. However, mean total GFR in nephrotomy-group cats was n...

Solitary Brain Metastasis From Renal Cell Carcinoma 15 Years After Nephrectomy

Abstract: A 77-year-old man presented with a metastatic brain tumor 15 years after nephrectomy for a renal cell carcinoma. Neurological examination showed recent memory disturbance and slight right hemiparesis. Magnetic resonance imaging revealed a round well-demarcated mass extending from the left thalamus to the left trigone of the lateral ventricle. Preoperative angiography showed tumor staining. Surgery was performed by opening the inferior temporal sulcus. Only biopsy could be performed because of extensive bleeding from the tumor. Histological examination identified metastatic renal cell carcinoma. Gamma knife surgery was performed which resulted in resolution of his hemiparesis. Metastatic renal cell carcinoma should be considered even if nephrectomy was performed 10 or more years before presentation.

R561C missense mutation in the SMARCAL1 gene associated with mild Schimke immuno-osseous dysplasia

Abstract: Autosomal-recessive Schimke immuno-osseous dysplasia (SIOD) characterized by spondyloepiphyseal dysplasia, focal-segmental glomerulosclerosis (FSGS), T-cell immunodeficiency and facial dysmorphism is caused by defects in the SMARCAL1 gene. The gene product is involved in the transcriptional regulation of other genes. A 12-year-old boy of consanginous Turkish descent developed disproportionate short stature from spondyloepiphyseal dysplasia at the age of 6 and nephrotic syndrome at the age of 10 years. Renal biopsy revealed FSGS, the kidney function was normal, T-lymphocytes were diminished without infectious complications, and he has had no cerebral ischemia. Analysis of the patient’s SMARCAL1 gene revealed a novel homozygous C1798T transition leading to a R561C substitution. The parents and two healthy sisters were found to be heterozygous. A younger brother, who is also homozygous for the mutation, is clinically asymptomatic and has no proteinuria at the age of 18 months. Still, his CD4 cells are diminished. For SMARCAL1 mutations a clear genotype-phenotype correlation has been reported: severe SIOD with in utero or early-childhood onset leading to end-stage renal disease within a few years is caused by nonsense, frame shift or splice mutations. Many patients die from infections and cerebrovascular insults during childhood. Mild SIOD manifests later and progresses more slowly without infectious or cerebral vascular complications—the underlying defect being missense mutations in all three patients reported so far. The novel R561C missense mutation in our patient with mild SIOD is additional evidence for the genotype-phenotype correlation reported for SMARCAL1 mutations.

Does nephrectomy for trauma increase the risk of renal failure

Abstract: Renal failure is a feared complication following operations for severe trauma. Injuries to the kidney may be managed by nephrectomy or nephrorrhaphy. Nephrectomy may increase the risk of renal failure in already at-risk trauma patients. Nephrectomy for trauma should be avoided to the extent possible because it is associated with renal failure. From a prospectively collected trauma database, 59 patients with nephrectomy were matched at 1:1 ratio with 59 patients with nephrorrhaphy. Matching criteria were age (+/- 5 years), Injury Severity Score (+/- 3), abdominal Abbreviated Injury Score (+/- 1), and mechanism of injury (blunt or penetrating). The rates of renal function compromise (defined as a serum creatinine level >2 mg/dl for more than 2 days) and renal replacement therapy (continuous or intermittent) were compared in the two groups. The two groups were well-matched and similar with regard to injury severity and organs injured. Between nephrectomy and nephrorrhaphy patients, there were no differences in renal function compromise (10% vs. 14%, p = 0.57), renal replacement therapy (5% vs. 0%, p = 0.12), length of hospital stay (19 +/- 26 vs. 20 +/- 21, p = 0.8), and mortality (15% vs. 12%, p = 0.59). Salvaging the injured kidney does not seem to offer an obvious clinical benefit regarding postoperative renal function. Given the increased operative complexity of nephrorrhaphy in comparison to nephrectomy and the frequent need to abbreviate the operation in patients with severe trauma, nephrectomy should not be avoided when appropriate.

Radiofrequency tissue ablation in an experimental model of grade IV renal trauma: A preliminary report

Abstract: The kidney is one of the most frequently injured intraabdominal organs. In this study, we investigated the efficacy and safety of radiofrequency ablation (RFA) as a kidney-preserving hemostatic technique for grade IV renal trauma. A grade IV injury was induced in the right kidney of 12 Landrace pigs. Then RFA was applied around the injury in 10 animals until hemostasis was achieved; two animals were not treated (control group). The treated animals were killed humanely on days 0, 3, 7, 14 and 21 and examined. The kidneys were subjected to histologic and radiologic examination. The two untreated animals died from hypovolemic shock. Hemostasis was achieved in all treated animals. We had no operative deaths and no morbidity. No blood, pus, urine, or other fluid was found at the time of death. In one animal, a fistulous lesion leading to the collecting system was identified, but no urine leakage was observed. At histology, the ablated areas were found to consist of three zones: an inner necrotic one, a zone of neutrophils digesting necrotic tissue, and an outer zone with possibly reversible damage. Radiofrequency ablation is an efficient and safe hemostatic method for grade IV renal trauma. Further study is needed to investigate the possible application of this method to humans and its percutaneous or laparoscopic use.

Role of three-dimensional imaging in surgical planning for kidney surgery.

Abstract: Three-phase helical CT is recommended for 3D imaging for surgical planning [12–15] (Fig. 1). When examining the urinary tract, an unenhanced scan is taken to locate the kidneys and assess calcifications, and to provide a baseline with which to characterize renal lesions after the intravenous administration of contrast medium. Next, non-ionic contrast medium is injected at 3–4 mL/s through an 18 G intravenous catheter, and a corticomedullary or vascular phase scan taken to identify renal vasculature, including early and segmental renal artery branches and late vein confluences [16]; this scan phase can also contribute to characterizing the lesion. The delay time is determined either by timing the bolus, or via an automated system, and begins 30–40 s after the start of infusing the contrast medium. For lesion detection and characterization, the nephrographic phase scan remains the most sensitive phase [17–19]. The nephrographic phase begins 120–150 s after the start of infusing the contrast medium. The test bolus or a 20-mL contrast medium pre-load can be used to opacify the collecting system to determine if a tumour involves the calyces.

Open surgical management of renal cell carcinoma in the era of minimally invasive kidney surgery.

Abstract: ligation of the renal vessels to minimize risk of haematogenous spread of tumour emboli, en bloc excision of Gerota’s fascia with the kidney and adrenal gland intact, and an extensive lymph-node dissection (LND), including para-aortic and para-caval nodes from the crus of the diaphragm to the aortic bifurcation. Using these principles resulted in an improved overall 5-year survival of 52%, and 66% for a subset of patients with clinically localized disease when compared with the then-accepted simple nephrectomy [2]. Contemporary series using the 1997 TNM staging criteria with threshold of 7 cm for T1 stage, and all renal vein and vena caval involvement classified as stage T3, report 5year cancer-specific survival rates of 91%, 74%, 67% and 32% for stages T1 to T4, respectively [3,4]. There have been significant advances in the diagnosis, staging, and treatment of patients with RCC during the last two decades [5]. As such, several aspects of the open RN as classically described are now under re-evaluation, to optimize the operation and offer a more limited resection based on individualized imaging, staging and prognostic information.

Reconstruction techniques in renal injury

Abstract: OBJECTIVES Kidney repair reconstruction techniques are controversial. The conventional technique is suturing, but this is usually with further loss of viable tissue as it promotes scaring. In this animal model, we investigated the parenchymal effect of different sutures and methods. METHODS We carried out this study in the year 2000 in the Animal Laboratory of Dicle University, Diyarbakir, Turkey. We used 40 New Zealand white rabbits in this study, randomized into 5 groups. We separated the left kidney from Gerota's fascia, and performed standard lacerations with incisions 5 mm deep and 10 mm in length. We performed no reconstruction procedure in group 1, and used homeostatic collagen powder in group 2. We primarily sutured the lacerations with chromic gut (4/0) in group 3, and sutured the kidney in group 4 with polyglactin (4/0). We wrapped the kidney with a polyglactin mesh in group 5. We sacrificed 2 rabbits in each group postoperatively on day 2, 15, 45 and 90, and performed left nephrectomy for histological investigation, and assessed interstitial inflammation. RESULTS While group 5 established the best results, the other 4 groups had similar intermediate results. The pseudocapsule was visible macroscopically in the polyglactin mesh group. We could see mononuclear cell infiltration, dilatation of tubules, atrophy of tubules, and interstitial fibrosis in all groups except group 5. CONCLUSIONS In this animal model, we found that the most appropriate repair material for kidney surgery was polyglactin mesh.

Hydronephorsis due to pelvi-ureteric obstruction in children. An assessment of the anterior transperitoneal approach.

Abstract: Twenty-four children (29 kidneys) with hydronephrosis due to pelvi-ureteric obstruction are reviewed. Conservative plastic surgery to the pelviureterc junction is recommended and an anterior transperitoneal approach to the renal pelvis is advocated. Extrarenal drainage should be used and pyelostomy or nephrostomy is not usually necessary. While the clinical results are excellent the radiological changes tend to be more disappointing and a longer follow-up period may be required to improve the radiological appearances.