Cardiorespiratory Fitness: Reference on the Six-Minute Walk Test and Oxygen Consumption in Adolescents from South-Central Chile.

Cardiorespiratory fitness (CRF) provides oxygen to the exercising muscles and is related to body adiposity, with cardiometabolic variables. The aim was to develop reference values and a predictive model of CRF in Chilean adolescents. A total of 741 adolescents of both genders (15.7 years old) participated in a basic anthropometry, performance in the six-minute walk test (SMWT), and in Course Navette was measured. Percentiles were determined for the SMWT, for the V̇O2max, and an equation was developed to estimate it. The validity of the equation was checked using distribution assumptions and the Bland-Altman diagram. The STATA v.14 program was used (p < 0.05). The 50th percentile values for males and females in the SMWT and in the V̇O2max of Course Navette were, respectively, from 607 to 690 and from 630 to 641 m, and from 43.9 to 45 and from 37.5 to 31.5 mlO2·kg·min-1, for the range of 13 to 17 years. For its part, the model to predict V̇O2max incorporated gender, heart rate, height, waist-to-height ratio (WHR), and distance in the SMWT (R2 = 0.62; estimation error = 0.38 LO2·min-1; p <0.001). Reference values can guide physical fitness in Chilean adolescents, and V̇O2max was possible to predict from morphofunctional variables.

Comparison of temperature change and resulting ablation size induced by a 902-928 MHz and a 2450 MHz microwave ablation system in in-vivo porcine kidneys.

INTRODUCTION: Microwave ablation (MWA) uses heat to ablate undesired tissue. Development of pre-planning algorithms for MWA of small renal masses requires understanding of microwave-tissue interactions at different operating parameters. The objective of this study was to compare the performance of two MWA systems in in-vivo porcine kidneys. METHODS: Five ablations were performed using a 902-928 MHz system (24 W, 5 min) and a 2450 MHz system (180 W, 2 min). Nonlinear regression analysis of temperature changes measured 5 mm from the antenna axis was completed for the initial 10 s of ablation using the power equation ΔT=atb and after the inflection point using an exponential equation. Thermal damage was calculated using the Arrhenius equation. Long and short axis ablation diameters were measured. RESULTS: The average 'a' varied significantly between systems (902-928 MHz: 0.0299 ± 0.027, 2450 MHz: 0.1598 ± 0.158), indicating proportionality to the heat source, but 'b' did not (902-928 MHz: 1.910 ± 0.372, 2450 MHz: 2.039 ± 0.366), signifying tissue type dependence. Past the inflection point, average steady-state temperature increases were similar between systems but reached more quickly with the 2450 MHz system. Complete damage was reached at 5 mm for both systems. The 2450 MHz system produced significantly larger short axis ablations (902-928 MHz: 2.40 ± 0.54 cm, 2450 MHz: 3.32 ± 0.41cm). CONCLUSION: The 2450 MHz system achieved similar steady state temperature increases compared to the 902-928 MHz system, but more quickly due to higher output power. Further investigations using various treatment parameters and precise thermal sensor placement are warranted to refine equation parameters for the development of an ablation model.

Neoplasia de Células Dendríticas Plasmocitoides blásticas: reporte del primer caso en Ecuador / Blastic Plasmacytoid Dendritic Cell Neoplasm : First Case Report in Ecuador

La Neoplasia de Células Dendríticas Plasmocitoides blásticas (Blastic Plasmacytoid dendritic cell neoplasm ­ BPDCN) es una neoplasia hematológica rara, agresiva, de difícil diagnóstico y con alta mortalidad. Se describe el primer caso en el Ecuador de un paciente joven sin antecedentes patológicos relevantes, ingresado al servicio de Medicina Interna del Hospital Enrique Garcés por presentar máculas cutáneas, artralgias y mialgias, que se complica con derrame pleural tipo exudativo y mala mecánica respiratoria. Exámenes de extensión revelaron: Leucemia mieloide aguda de tipo M2, motivo por el cual fue referido a centro oncológico de referencia para completar estudio y manejo. Estudios citogenéticos y fenotípicos corroboraron el diagnóstico de BPDCN, se instauró tratamiento con protocolo Hyper-CVAD, sin embargo, el paciente presentó compromiso respiratorio, renal y hematológico que progresó a choque refractario y óbito. La naturaleza agresiva de esta rara leucemia es una limitante en el tiempo para instaurar un tratamiento dirigido, determinando en la mayoría de los casos una alta mortalidad

La Neoplasia de Células Dendríticas Plasmocitoides blásticas (Blastic Plasmacytoid dendritic cell neoplasm ­ BPDCN) es una neoplasia hematológica rara, agresiva, de difícil diagnóstico y con alta mortalidad. Se describe el primer caso en el Ecuador de un paciente joven sin antecedentes patológicos relevantes, ingresado al servicio de Medicina Interna del Hospital Enrique Garcés por presentar máculas cutáneas, artralgias y mialgias, que se complica con derrame pleural tipo exudativo y mala mecánica respiratoria. Exámenes de extensión revelaron: Leucemia mieloide aguda de tipo M2, motivo por el cual fue referido a centro oncológico de referencia para completar estudio y manejo. Estudios citogenéticos y fenotípicos corroboraron el diagnóstico de BPDCN, se instauró tratamiento con protocolo Hyper-CVAD, sin embargo, el paciente presentó compromiso respiratorio, renal y hematológico que progresó a choque refractario y óbito. La naturaleza agresiva de esta rara leucemia es una limitante en el tiempo para instaurar un tratamiento dirigido, determinando en la mayoría de los casos una alta mortalidad

Mental health determines the quality of life in patients with cancer-related neuropathic pain in Quito, Ecuador, / La salud mental determina la calidad de vida de los pacientes con dolor neuropático oncológico en Quito, Ecuador

Abstract Objective: To identify the main factors determining the health related quality of life (HRQL) in patients with cancer-related neuropathic pain in a tertiary care hospital. Methods: A cross-sectional analytical study was performed on a sample of 237 patients meeting criteria for cancer-related neuropathic pain. Clinical and demographic variables were recorded including, cancer type, stage, time since diagnosis, pain intensity, physical functionality with the palliative performance scale (PPS), and anxiety and depression with the hospital anxiety and depression scale (HADS). Their respective correlation coefficients (r) with HRQL assessed with the SF-36v2 Questionnaire were then calculated. Linear regression equations were then constructed with the variables that showed an r > 0.5 with the HRQL. Results: The HRQL scores of the sample were 39.3 ± 9.1 (Physical Component) and 45.5 ± 13.8 (Mental Component). Anxiety and depression strongly correlated with the mental component (r = -0.641 and r = -0.741, respectively) while PPS score correlated with the physical component (r = 0.617). The linear regression model that better explained the variance of the mental component was designed combining the Anxiety and Depression variables (r = 77.3%; p < 0.001). Conclusions: The strong influence of psychiatric comorbidity on the HRQL of patients with cancer-related neuropathic pain makes an integral management plan essential for these patients to include interventions for its timely diagnosis and treatment.

Resumen Objetivo: Identificar los principales determinantes de la calidad de vida relacionada con la salud (CVRS) de pacientes con dolor neuropático oncológico en un hospital de tercer nivel de atención. Métodos: Estudio transversal analítico. En una muestra de 237 pacientes con criterios de dolor neuropático de origen oncológico, se midieron variables clínico-demográficas: tipo de cáncer, estadio, tiempo de diagnóstico, intensidad del dolor, funcionalidad física con la escala PPS, y ansiedad y depresión con la escala HADS. Se calcularon sus respectivos coeficientes de correlación (r) con la CVRS medida con el cuestionario SF-36v2TM. Con las variables que mostraron r > 0,5 con la CVRS, se construyeron ecuaciones de regresión lineal. Resultados: La población mostró puntuaciones de CVRS de 39,3 ±9,1 (componente físico) y 45,5 ±13,8 (componente mental). Ansiedad y depresión tuvieron correlación fuerte con el componente mental (r = -0,641 y r = -0,741 respectivamente), mientras que la PPS la tuvo con el componente físico (r = 0,617). El modelo de regresión lineal que mejor explicó la varianza del componente mental fue diseñado con las variables ansiedad y depresión combinadas (R= 77,3%; p< 0,001). Conclusiones: La fuerte influencia de la comorbilidad psiquiátrica en la CVRS de los pacientes con dolor neuropático oncológico hace necesario que el plan de atención integral de estos pacientes incluya intervenciones para su oportuno diagnóstico y tratamiento.

[Mental Health Determines the Quality of Life in Patients With Cancer-Related Neuropathic Pain in Quito, Ecuador]. / La salud mental determina la calidad de vida de los pacientes con dolor neuropático oncológico en Quito, Ecuador.

OBJECTIVE: To identify the main factors determining the health related quality of life (HRQL) in patients with cancer-related neuropathic pain in a tertiary care hospital. METHODS: A cross-sectional analytical study was performed on a sample of 237 patients meeting criteria for cancer-related neuropathic pain. Clinical and demographic variables were recorded including, cancer type, stage, time since diagnosis, pain intensity, physical functionality with the Palliative Performance Scale (PPS), and anxiety and depression with the Hospital Anxiety and Depression Scale (HADS). Their respective correlation coefficients (r) with HRQL assessed with the SF-36v2 Questionnaire were then calculated. Linear regression equations were then constructed with the variables that showed an r≥.5 with the HRQL. RESULTS: The HRQL scores of the sample were 39.3±9.1 (Physical Component) and 45.5±13.8 (Mental Component). Anxiety and depression strongly correlated with the mental component (r=-.641 and r=-.741, respectively) while PPS score correlated with the physical component (r=.617). The linear regression model that better explained the variance of the mental component was designed combining the Anxiety and Depression variables (R=77.3%; P<.001). CONCLUSIONS: The strong influence of psychiatric comorbidity on the HRQL of patients with cancer-related neuropathic pain makes an integral management plan essential for these patients to include interventions for its timely diagnosis and treatment.

Prueba de escalón de Mcardle: una ecuación para estimar el Vo2 máx. en estudiantes de educación física / Mcardle step test: an equation for estimating the VO2 max. in physical education students

El objetivo de esta investigación es obtener una ecuación para determinar VO2 máx. a través de una prueba submáxima utilizando la frecuencia cardíaca de recuperación (FCr). Se diseñó en un estudio descriptivo correlacional dentro de un marco cuantitativo y se evaluó a 18 sujetos, 9 damas y 9 varones, de primero a cuarto año estudiantes de educación física con un muestreo de tipo intencional. Se midió la FCr en la prueba submáxima en escalón de McArdle, utilizando el monitor de FC marca Polar mo-delo V800 (Finlandia), y el consumo máximo de oxígeno (VO2 máx.) en el test de esfuerzo máximo de Bruce con el analizador de gases marca COSMED, modelo Fitmate PRO (Italia). En los resultados, la correlación (coeficiente de Pearson) que se obtuvo fue de r = ­0.84 (p<0.001) la cual se encuentra en una categoría considerable, obteniendo la ecuación y = ­0.4132 x + 110.68 con un error de estimación estándar (EEE) de 5.8 ml.kg.min­1.

The main aim of this research is to obtain an equation to determine the VO2 max through a submaximal test using heart rate recovery (HRr). A correlational descriptive study was designed within a quantitati-ve framework, where 18 subjects, all physical education college students, from freshman to senior year, were evaluated (9 females and 9 males), using diversity sampling (intentional). The HRr was measured in the McArdle submaximal step using the HR monitor, Polar V800 model (Finland), and the VO2 max. in the Bruce maximum effort test was measured with the gas analyzer COSMED model Fitmate PRO (Italy). In the results, the correlation (Pearson coefficient) obtained was r = −0.84 (p<0.001) which is within the considerable category, obtaining the equation y = 0.4132 x + 110.68 with a standard error of estimation (SEE) of 5.8 ml.kg.min−1.

In Vivo Porcine Model of Venous Air Embolism During Pars Plana Vitrectomy.

PURPOSE: Venous air embolism (VAE) during pars plana vitrectomy (PPV) can occur owing to improper positioning of the infusion cannula in the suprachoroidal space and may lead to sudden compromise of cardiac circulation and death. This was an in vivo demonstration of fatal VAE during PPV to show that air can travel from the suprachoroidal space into the central circulation. DESIGN: Experimental in vivo surgical study on porcine eyes. METHODS: Experimental PPV under general anesthesia was performed on porcine eyes (Yorkshire species) at a University Surgical Training & Education Center. Infusion cannulas were placed into the suprachoroidal space and fluid-air exchange (FAE) was started with sequential increases in infusion air pressure. Vital signs of porcine animals were continuously monitored and recorded in real time during the PPV, including end-tidal carbon dioxide (ETCO2), oxygen saturation (SaO2), intra-arterial blood pressure, electrocardiography (EKG), and transesophageal echocardiography (TEE). RESULTS: Intracardiac air was detected on TEE less than 30 seconds after increasing air infusion pressure to 60 mm Hg. ETCO2 declined precipitously, followed by hypotension and EKG changes. Oxygen desaturation was a late phenomenon. The animal died within 7 minutes of VAE. During autopsy, the heart was open under water and air escaped from the right ventricle. CONCLUSION: This in vivo porcine model confirms that during the FAE in PPV, pressurized air from an infusion cannula malpositioned in the suprachoroidal space can transit through the eye to the central circulation, resulting in fatal VAE.

Mathematical and Ex Vivo Thermal Modeling for Renal Tumor Radiofrequency Ablation with Pyeloperfusion.

BACKGROUND AND PURPOSE: Radiofrequency ablation (RFA) is an effective technique for the treatment of patients with small renal tumors, although it is often limited to tumors at least 2 cm from the renal pelvis or ureter. Retrograde pyeloperfusion (PPF) of the pelvis with cold saline during RFA may protect the pelvis and ureter. We designed a mathematical and ex vivo model of RFA to investigate the effects of PPF. METHODS: Our theoretical model uses heat transfer principles simplifying the RFA probe to a heat-emitting cylinder within a material. In the ex vivo model, an RFA probe was placed 18 mm from the pelvis in porcine kidneys and with temperature probes on either side of the RFA probe. Control trials with no PPF were compared with either cold saline (2°C), warm saline (38°C), or antifreeze (-20°C) pumped into the renal calix at a rate of 60 mL/min. Ablated volumes were measured and confirmed histologically. RESULTS: The average steady state temperatures at each probe were highest with no PPF, followed by warm saline, cold saline, then antifreeze. Compared with no PPF, temperatures were significantly (P<0.05) colder with warm saline (-8.4°C), cold saline (-18°C), and significantly colder at the calix (warm -14°C, cold -27°C). While RFA output a constant voltage, significantly lower resistances in warm (171Ω) and cold (124Ω) PPF vs no PPF (363Ω) translated to significantly greater power outputs in warm (40 W) and cold (42 W) vs no PPF (14 W). The ablated volumes were significantly higher in warm saline (2.3 cm(3)) vs cold saline (0.84 cm(3)) and no PPF (1.1 cm(3)). Mathematical modeling produced a predictive temperature curve with R2=0.44. CONCLUSION: PPF lowers temperatures throughout the entire kidney during RFA, most notably near the collecting system and is dependent on the temperature of the liquid used. In addition, PPF may cause less charring of the tissue around the probe resulting in lower resistance and higher power outputs.

Emerging needle ablation technology in urology.

PURPOSE OF REVIEW: Thermal ablation of urologic tumors in the form of freezing (cryoablation) and heating (radiofrequency ablation) have been utilized successfully to treat and ablate soft tissue tumors for over 15 years. Multiple studies have demonstrated efficacy nearing that of extirpative surgery for certain urologic conditions. There are technical limitations to their speed and safety profile because of the physical limits of thermal diffusion. RECENT FINDINGS: Recently, there has been a desire to investigate other forms of energy in an effort to circumvent the limitations of cryoblation and radiofrequency ablation. This review will focus on three relatively new energy applications as they pertain to tissue ablation: microwave, irreversible electroporation, and water vapor. High-intensity-focused ultrasound nor interstitial lasers are discussed, as there have been no recently published updates. SUMMARY: Needle and probe-based ablative treatments will continue to play an important role. As three-dimensional imaging workstations move from the advanced radiologic interventional suite to the operating room, surgeons will likely still play a pivotal role in the +-application of these probe ablative devices. It is essential that the surgeon understands the fundamentals of these devices in order to optimize their application.

Radio-frequency ablation helps preserve nephrons in salvage of failed microwave ablation for a renal cancer in a solitary kidney.

Recurrent tumors after renal ablative therapy present a challenge for clinicians. New ablative modalities, including microwave ablation (MWA), have very limited experience in methods of retreating ablation failures. Additionally, in MWA, no long-term outcomes have been reported. In patients having local tumor recurrence, options for surveillance or surgical salvage must be assessed. We present a case to help assess radio-frequency ablation (RFA) for salvage of failed MWA. We report a 63-year-old male with a 4.33-cm renal mass in a solitary kidney undergoing laparoscopic MWA with simultaneous peripheral fiber-optic thermometry (Lumasense, Santa Clara, CA, USA) as primary treatment. Follow-up contrast-enhanced computed tomography (CT) scan was performed at 1 and 4.3 months post-op with failure occurring at 4.3 months as evidenced by persistent enhancement. Subsequently, a laparoscopic RFA (LRFA) with simultaneous peripheral fiber-optic thermometry was performed as salvage therapy. Clinical and radiological follow-up with a contrast-enhanced CT scan at 1 and 11 months post-RFA showed no evidence of disease or enhancement. Creatinine values pre-MWA, post-MWA, and post-RFA were 1.01, 1.14, and 1.17 mg/ml, respectively. This represents a 15% decrease in estimated glomerular filtration rate (eGFR) (79 to 67 ml/min) post-MWA and no change in eGFR post-RFA. Local kidney tumor recurrence often requires additional therapy and a careful decisionmaking process. It is desirable not only to preserve kidney function in patients with a solitary kidney or chronic renal insufficiency, but also to achieve cancer control. We show the feasibility of RFA for salvage treatment of local recurrence of a T1b tumor in a solitary kidney post-MWA.

Ablative therapies for small renal tumours.

Improvements in imaging technology have resulted in an increase in detection of small renal masses (SRMs). Minimally invasive ablation modalities, including cryoablation, radiofrequencey ablation, microwave ablation and irreversible electroporation, are currently being used to treat SRMs in select groups of patients. Cryoablation and radiofrequency ablation have been extensively studied. Presently, cryoablation is gaining popularity because the resulting ice ball can be visualized easily using ultrasonography. Tumour size and location are strong predictors of outcome of radiofrequency ablation. One of the main benefits of microwave ablation is that microwaves can propagate through all types of tissue, including desiccated and charred tissue, as well as water vapour, which might be formed during the ablation. Irreversible electroporation has been shown in animal studies to affect only the cell membrane of undesirable target tissues and to spare adjacent structures; however, clinical studies that depict the efficacy and safety of this treatment modality in humans are still sparse. As more experience is gained in the future, ablation modalities might be utilized in all patients with tumours <4 cm in diameter, rather than just as an alternative treatment for high-risk surgical patients.

Oncologic outcomes using real-time peripheral thermometry-guided radiofrequency ablation of small renal masses.

BACKGROUND AND PURPOSE: With the increased incidence of low-stage renal cancers, thermal ablation technology has emerged as a viable treatment option for extirpation in selected persons and is supported by the current American Urological Association guidelines. We present a 9-year, single institution experience with radiofrequency ablation (RFA) using real-time peripheral temperature monitoring of small renal masses focusing on oncologic outcomes. PATIENTS AND METHODS: We reviewed our prospectively collected database of patients with renal masses who were treated between November 2001 and January 2011 with laparoscopic (LRFA) or CT-guided percutaneous RFA (CTRFA) with simultaneous real-time peripheral fiberoptic thermometry. Patients were followed radiographically at 1 month, 6 months, 1 year, and then annually. Clinicopathologic outcomes were collected and analyzed. RESULTS: A total of 274 patients (211 male) aged 18 to 88 years (mean 67 years) with 292 renal tumors underwent LRFA (112) or CTRFA (180). Mean tumor size was 2.5 cm (0.7-5.3 cm). An intraoperative preablation biopsy showed 197 (67.4%) renal-cell carcinomas (RCC), and 77 (26.4%) benign tumors. Mean follow-up was 26 months (1-98 mos). The single ablation treatment radiographic success rate was 96% for all tumors and 94% for RCC. Metastatic RCC developed in one patient, who died. The Kaplan-Meier (KM) 3-year and 5-year cancer-specific survival was 100% and 98.6%, respectively. The KM 3-year and 5-year overall survival was 90.4% and 74.2%, respectively. CONCLUSION: RFA is a clinically effective and safe nephron-sparing treatment of patients with small renal masses. Our large cohort and intermediate-term experience adds to the building evidence for the efficacy of RFA for small renal cancers.

Development and evaluation of a novel cadaveric model for performance of image-guided percutaneous renal tumor ablation.

INTRODUCTION: Thermal ablation is a well established treatment option for the management small renal masses. Increasingly, renal ablation is performed via a percutaneous approach. However, most urologists are not formally trained in image-based deployment of ablation needles. To address this need, we created a novel training model to teach urologists to perform precise and accurate percutaneous needle placement. This teaching model was implemented as part of a recent training course on tissue ablation organized by the American Urological Association. METHODS: Two fresh frozen human cadavers (Anatomic Gifts Registry, Hanover, Maryland) were used in the model. Plumber's Putty (Oatey, Cleveland, Ohio) and nonpitted olives soaked in Isovue (Bracco Dianostics, Inc, New York, New York) were used to create ablation targets. Course participants underwent a tutorial on the computed tomography (CT)-guided deployment of a 19-gauge Yueh Needle (Cook Medical, Bloomington, Indiana) or Cool-tip radio-frequency ablation (RFA) probe (Covidien, Inc, Boulder, Colorado). After each needle placement, a CT scan was performed to assess successful deployment. Participants were then queried regarding their experience. RESULTS: A total of 18 urologists performed needle or radio-frequency ablation probe placement on 2 cadavers. A mean of 3.39 (range 2-5) attempts was required to hit targets. Subjectively, participants noted an increase in confidence performing percutaneous needle deployment. The cadaver laboratory exposed participants to pretreatment planning, tactile feel of needle placement, needle readjustment, and 3-D spatial relationships of a percutaneous approach. CONCLUSIONS: The presented cadaveric model is an effective tool for teaching percutaneous needle placement. All urologists evaluated noted increased confidence in this technique after training on the model.

Radiofrequency ablation for treatment of renal tumors: technological principles and outcomes.

Radiofrequency ablation (RFA) is a minimally invasive, energy-based, needle-ablative treatment modality that is currently being used to treat small renal masses (SRMs) and offers advantages over extirpative techniques. RFA treats SRM with heat induced by the tissue impedance to radiofrequency current emitted from a needle probe within the SRM. Currently available RFA systems use either an impedance- or temperature-based treatment algorithm to reach treatment end point while minimizing risk of carbonization. Physical limitations, such as electrical property heterogeneity and convective heat loss due to blood flow, and technical considerations should be addressed when performing RFA. Nonetheless, investigations with intermediate follow-up have demonstrated single-treatment radiographic recurrence-free rates of >90%. Future trends include the use of noninvasive imaging thermometry, electromagnetic targeting and adjuvant techniques.

Improved targeting of radio-frequency ablation probes and thermal sensors: a preliminary investigation of flat-panel CT-guided ablation of renal tumors performed in the cardiac catheterization laboratory.

Flat-panel detector CT (FD-CT) provides cross-sectional CT-images while offering an improved workspace using fluoroscopic guidance for thermal probe placement such as for radiofrequency ablation (RFA) needles and thermal sensors. The purpose of this article is to test the feasibility of FD-CT in the application of renal tumor ablation in a "hybrid operating room" environment. Eleven patients with renal masses diagnosed preprocedurally with contrast-enhanced CT scan underwent core biopsy and simultaneous CT-RFA under general anesthesia with FD-CT guidance in the cardiac catheterization laboratory. Scans were taken preablation for tumor targeting, intermittently for probe placement and guidance of temperature sensors, and postablation. Perioperative and postoperative outcomes, pathologic results, and radiographic follow-up were recorded for each patient. Target temperatures >60°C to guide treatment end point were reached for each tumor periphery. Biopsy pathology showed 6/11 (55%) to be renal-cell carcinoma, and 2/11 (18%) to be benign; 3/11 (27%) had an indeterminate biopsy result. Three Clavien grade I complications occurred. One patient showed evidence of recurrent disease on postoperative CT scan. In our experience, we have found FD-CT-guided ablation of small renal tumors to be feasible using this advanced targeting system.

Initial experience with laparoendoscopic single-site simple nephrectomy using the TransEnterix SPIDER surgical system: assessing feasibility and safety.

PURPOSE: The goal of this report is to describe our initial clinical experience performing a simple nephrectomy with the SPIDER (Single Port Instrument Delivery Extended Reach) laparoendoscopic single-site (LESS) surgical system. PATIENT AND METHODS: One patient with a nonfunctioning kidney secondary to a ureteropelvic junction obstruction underwent a simple nephrectomy through a single incision performed using the SPIDER surgical system. We assessed the technical feasibility, efficiency, and perioperative outcomes. RESULTS: The SPIDER-LESS nephrectomy was performed successfully without additional skin incisions for laparoscopic ports, instrument clashing, or open conversion. Total operative time was 210 minutes with blood loss of 50 mL. The patient experienced no intraoperative or postoperative complications. Pathologic evaluation confirmed atrophic renal parenchyma. CONCLUSIONS: The SPIDER surgical system LESS nephrectomy is feasible and safe. Future refinements of the technology and prospective studies are needed to further optimize its application in urology.

Laparoendoscopic single site nephrectomy with the SPIDER surgical system: engineering advancements tested in a porcine model.

UNLABELLED: Abstract Background and Purpose: The Single Port Instrument Delivery Extended Reach (SPIDER) surgical system was developed for true continuous instrument triangulation during laparoendoscopic single site (LESS) surgery. We present our initial preclinical experience with the SPIDER surgical system during renal surgery. MATERIAL AND METHODS: Bilateral laparoscopic nephrectomies were performed in a live adult porcine animal model using the SPIDER device. A standard surgical approach was used via direct video guidance. RESULTS: The procedure was successfully performed without surgical error or complication. The SPIDER system proved easy to use with only a minimal learning curve. Intracorporeal surgical knots were tied without difficulty using this single site system. CONCLUSIONS: Our initial experience with the SPIDER surgical system during renal surgery is promising. SPIDER allows for true single port instrument triangulation offering a superior operative experience to currently available LESS surgical systems.

Initial experience using microwave ablation therapy for renal tumor treatment: 18-month follow-up.

OBJECTIVES: To assess efficacy and morbidity of microwave ablation (MWA) for small renal tumors in an initial cohort of patients. MWA is a recently introduced thermal needle ablation treatment modality with theoretical advantages compared with radiofrequency ablation, such as greater intratumoral temperatures, lack of a grounding pad, and superior convection profile. However, experience has been limited in the human kidney. METHODS: Ten patients with a single, solid-enhancing renal tumor from June 2008 to November 2008 received laparoscopic or computed tomography-guided percutaneous MWA at a tertiary referral center with ≥14 months of follow-up. MWA was performed using the Valleylab Evident, 915-MHz MWA system at 45 W with intraoperative biopsy before ablation, and peripheral fiberoptic thermometry to determine the treatment endpoints. The patients were followed up with contrast-enhanced computed tomography at 1 month, 6 months to 1 year, and annually to monitor for tumor recurrence. RESULTS: The follow-up duration for the 6 male and 4 female patients (mean tumor size 3.65 cm, range 2.0-5.5; mean age 69.8 years) was 17.9 months. The recurrence rate, defined by persistent enhancement, was 38% (3 of 8). The intraoperative and postoperative complication rate was 20% and 40%, respectively. CONCLUSIONS: MWA resulted in poor oncologic outcomes with a significant complication rate at an intermediate level of follow-up. However, MWA has promising theoretical advantages and should not be discarded. Additional studies should be considered to better understand the microwave-tissue interaction and treatment endpoints for different size renal masses before widespread use.

Results of radiofrequency kidney tumor ablation: renal function preservation and oncologic efficacy.

OBJECTIVES: Radiofrequency ablation (RFA) is increasingly finding a place in the treatment of small renal masses (SRM). RFA may be able to provide better renal preservation, while achieving appropriate cancer control. This investigation takes a critical look at pertinent aspects of RFA principles and reviews oncological and renal function outcomes. METHODS: A review of the most current English literature using a PubMed search was done. Oncological and renal function outcomes were reviewed from selected articles published between 2003 and 2009. Oncological outcome was determined by "single treatment" success rate at first follow-up and "After single treatment" success rate after first follow-up. Renal function outcome was determined by either change in creatinine, creatinine clearance, or GFR after RFA. RESULTS: The mean tumor size was 2.5 cm for 16/17 studies. Average mean and median follow-up was 23.3 months in 13/17 studies and 19.8 months for 4/17 studies. "Single Treatment" success rates of 90-100% (average = 97.2%) were noted in 13 studies. Average increase in serum creatinine was +0.14 mg/dL in four studies. Serum creatinine and creatinine clearance change in one solitary kidney study was +11 mmol/L and -8 mL/min., respectively. CONCLUSIONS: RFA is fast emerging as a safe and efficacious treatment for small renal masses. Compared to extirpative treatment options, RFA seems to provide the lowest rate of renal impairment, while providing acceptable rates of tumor ablation. As long-term results emerge, this may become one of the treatment modalities for renal tumors in patients with solitary kidneys and renal impairment.