Obesity in Percutaneous Nephrolithotomy. Is Body Mass Index Really Important?

doi:10.1016/j.urology.2014.03.062

Urology

Volume 84, Issue 3, September 2014, Pages 538-543

https://doi.org/10.1016/j.urology.2014.03.062 Get rights and content

Objective

To evaluate the influence of obesity in the results of percutaneous nephrolithotomy (PCNL) in terms of efficacy and safety and to evaluate other aspects such as fluoroscopy time, radiation exposure, total operative time, hemoglobin loss, hospital stay, and the need of auxiliary procedures.

Materials and Methods

We evaluated prospectively all the PCNLs performed at our institution between 2011 and 2012. A series of perioperative and postoperative details were recorded in our database. The patients were distributed in 4 groups using World Health Organization's classification of body mass index (BMI): normal weight, ≤25 kg/m²; overweight, 25-29.9 kg/m²; obese, 30-39.9 kg/m²; and morbidly obese, ≥40 kg/m². Modified Clavien classification was used for reporting the complications. Results were compared between the groups using the chi square and multivariate logistic regression tests.

Results

A total of 255 procedures were performed between January 2011 and December 2012. Overall stone clearance was 76.3% and complication rate using the modified Clavien grading system was 31.4%. No statistical differences in terms of complication rate and stone free rate were noted between the 4 groups. Total operative time and radiation doses increase along with BMI. No difference was found in fluoroscopy time, failure to gain access, hospital stay, or need for auxiliary procedures.

Conclusion

Obesity does not increase complications in PCNL, and the efficacy of the technique is similar to normal weight patients with appropriate expertise. Total operative time and radiation exposure increase along with BMI, putting patients at risk.

Section snippets

Objective

The main objective was to evaluate the influence of overweight and obesity in the results of the PCNL in terms of efficacy and safety. Other aspects were evaluated as well, including total operative and fluoroscopy time, radiation exposure, hemoglobin loss, hospital stay, and the need of auxiliary procedures.

Materials and Methods

We included in our prospective study all the PCNLs performed at our institution between January 2011 and December 2012. Sample size was calculated with GPower, version 3.1,⁴ to achieve 80% power to detect a theoretical effect size (W) of at least 0.2 with chi square test using a significance level alpha of 0.05. A series of preoperative, intraoperative, and postoperative details were recorded in our database with emphasis on BMI, stone clearance, and postoperative complications. Stone burden,

Results

A total of 255 procedures were performed by 3 surgeons between January 2011 and December 2012; 141 patients (55.3%) were males and 114 (44.7%) were females. Age range was 18-85 years (mean, 55.3 years). The prevalence of arterial hypertension (HTA) and diabetes mellitus was 40% and 18.4%, respectively.

The overall mean stone burden was 8.4 ± 8.6 cm² (higher than other series, probably because we are the reference center for several hospitals). Most of the stones were located in the renal pelvis

Comment

An increase in the incidence of obesity has been observed worldwide, especially in high-income countries and this trend has been maintained during the last 3 decades.² Obesity predisposes to stone formation in several metabolic ways as well.⁵ Overweight and obesity have been associated with an increase in the frequency and severity of complications in a wide variety of surgical procedures and were associated with significantly higher all-cause mortality.⁶ Treatment of obese patients can be a

Conclusion

Obesity does not increase complications in PCNL, and the efficacy of the technique is similar to normal weight patients in high-volume centers with appropriate expertise in this condition. Total operative time and radiation exposure increases along with BMI, putting patients at risk. We recommend young urologists to avoid morbidly obese patients, especially at the beginning of the learning curve because of technical difficulties.

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Cited by (43)

Initial results of the implementation of an ambulatory mini percutaneous nephrolithotomy program
2023, Actas Urologicas Espanolas
Presentar nuestro protocolo de nefrolitotomía percutánea ambulatoria y evaluar los resultados iniciales del programa.
Se analiza la implantación clínica del protocolo con los 30 primeros casos de mininefrolitotomía percutánea ambulatoria realizados en nuestro centro entre abril de 2021 y septiembre de 2022. Se recogen datos demográficos, variables perioperatorias, complicaciones y necesidad de atención médica no planificada, stone-free rate, tipología litiásica y parámetros de satisfacción con el proceso de cirugía mayor ambulatoria.
Con una edad media de 60,2 ± 11,6 años se intervinieron un total de 30 pacientes que cumplían los criterios de inclusión. El tamaño medio de la litiasis fue de 15 mm [rango: 5-20]. No se registró ninguna complicación intraoperatoria. Todos los pacientes excepto uno fueron dados de alta el mismo día de la intervención, según lo planificado. El mes posterior al alta, la tasa de complicaciones, reconsulta a urgencias o reingreso hospitalario ha sido del 0%. La stone-free rate a los 3 meses ha sido del 83%. La satisfacción global de todo el proceso perioperatorio, valorada a través del cuestionario EVAN-G, fue de 124,3 puntos sobre un máximo de 150, equivalente a un 78,6% de grado de satisfacción.
La mininefrolitotomía percutánea en régimen ambulatorio puede instaurarse como una opción de asistencia en centros con experiencia en endourología, una unidad establecida de cirugía mayor ambulatoria y mediante una selección estricta de los pacientes. Nuestros resultados iniciales muestran un perfil de seguridad adecuado y un grado de satisfacción global elevado de los pacientes intervenidos en esta modalidad.
To present our program for ambulatory mini percutaneous nephrolithotomy and evaluate its initial results.
We analyzed the implementation of the protocol into the clinical practice with the first 30 outpatient mini percutaneous nephrolithotomy cases performed in our center between April 2021 and September 2022. Demographic characteristics, perioperative variables, complications and need for unplanned health care, stone-free rate, stone type and patient satisfaction with the major ambulatory surgery process were collected.
A total of 30 patients with a mean age of 60.2 ± 11.6 years who met the inclusion criteria underwent surgery. The mean stone size was 15 mm [range: 5-20]. No intraoperative complications were recorded. All patients except one were discharged the same day of surgery as planned. In the month following discharge, the rate of complications, emergency department revisits or hospital readmissions rates were 0%. Stone-free-rate at 3 months was 83%. Overall satisfaction with the whole perioperative process was assessed with the EVAN-G questionnaire, obtaining 124.3 points out of a maximum of 150, which is equivalent to a 78.6% level of satisfaction.
Ambulatory mini percutaneous nephrolithotomy can be implemented as a treatment option in centers with experience in endourology, an established major ambulatory surgery unit, and strictly selected patients. Our initial results show an adequate safety profile and high overall satisfaction perceived by patients undergoing the ambulatory approach.
Hemorrhagic complicationes after percutaneous nephrolithotomy: The importance of an early endovascular management
2021, Actas Urologicas Espanolas
La hemorragia secundaria a la fístula arteriovenosa (FAV) o al pseudoaneurisma (PA) es una complicación poco frecuente de la nefrolitotomía percutánea (NLPC). El objetivo de este estudio es evaluar las complicaciones hemorrágicas (CH) tras la NLPC y los resultados del tratamiento endovascular.
Entre mayo de 2009 y diciembre de 2019 se realizaron en nuestro centro 1.335 NLPC por litiasis renal. Analizamos la incidencia de CH tempranas y tardías, el tratamiento administrado, la necesidad de embolización posterior y los datos clínicos y analíticos de los pacientes.
Un total de 59 (4,4%) pacientes presentaron CH, y todos fueron tratados con arteriografía y embolización selectiva (AES) para controlar el sangrado. Se observó hematoma perirrenal en 38 pacientes (64%).
En cuanto a los hallazgos angiográficos, hubo 32 (54%) PA, 8 (14%) FAV, 4 (7%) extravasaciones por laceración vascular y 15 (25%) PA combinadas con FAV. En un caso, fueron necesarios 3 procedimientos para controlar la hemorragia. En 30 pacientes (51%) no se requirió transfusión de sangre, mientras que en 29 (49%) se transfundió una media de 1,3 unidades. La mediana de seguimiento fue de 24 ± 21 meses.
El intervalo de tiempo medio entre la NLPC y la AES fue de 7,3 ± 4,9 días. Un total de 24 (41%) pacientes reingresaron tras el alta debido a una CH tardía que requería AES. La demora entre el reingreso y la AES fue de 4,8 ± 4,6 horas de media.
Las CH tempranas y tardías tras la NLPC pueden ser mayores. El tratamiento con AES tras la detección precoz es un método efectivo y mínimamente invasivo que evita múltiples transfusiones de sangre, en muchos casos insuficientes.
Hemorrhage due to arteriovenous fistula (AVF) or pseudoaneurysm (PA) is a rare complication after percutaneous nephrolithotomy (PCNL). The objective of this study is to evaluate hemorrhagic complications (HC) after PCNL and the results of their endovascular treatment.
Between May 2009 and December 2019, 1335 PCNL were performed in our center for kidney stone disease. We analyzed the incidence of early and late HC, their management, the need for subsequent embolization, as well as clinical and analytical data of these patients.
A total of 59 (4.4%) patients presented HC. Bleeding was managed with arteriography and selective embolization (ASE). Perirenal hematoma was seen in 38 patients (64%).
Regarding angiographic findings, there were 32 (54%) PA, 8 (14%) AVF, 4 (7%) extravasations due to vascular laceration and 15 (25%) PA combined with AVF. In one case, 3 procedures were required to control the bleeding. In 30 patients (51%) blood transfusions were not necessary, while in 29 (49%), a mean of 1.3 units were transfused. Median follow-up was 24±21 months.
Mean time interval between PCNL and ASE was 7.3±4.9 days. A total of 24 (41%) patients were readmitted after discharge due to late HC requiring ASE. Delay between readmission and ASE was 4.8±4.6 hours in average.
Early and late HC after PCNL can be severe. Rapid identification and treatment with ASE is an effective and minimally invasive and avoids multiple blood transfusions which in many cases constitute an insufficient treatment.
Increasing Body Mass Index Steepens the Learning Curve for Ultrasound-guided Percutaneous Nephrolithotomy
2018, Urology
Citation Excerpt :
The morbidly obese are at a higher risk for complications related to major surgical procedures compared to normal weight individuals26 and may warrant care at specialized centers. The value of learning ultrasound-guided renal access in obese patients is especially high given that obese individuals are more susceptible to increased radiation exposure during fluoroscopy-guided PCNL.27,28 In obese patients, ultrasound-guided PCNL carries the advantage of a significant reduction in radiation exposure relative to fluoroscopy-guided PCNL compared to nonobese patients.29
To define how the learning curve for success in ultrasound-guided percutaneous nephrolithotomy (PCNL) is impacted by body mass index (BMI). Previous research has shown ultrasound-guided PCNL to be an effective method of nephrolithiasis treatment comparable to fluoroscopy-guided PCNL. A common concern for the ultrasound-guided approach is potential imaging difficulty in the obese patient population.
A prospective cohort study of consecutive patients undergoing PCNL with ultrasound guidance for renal tract access was performed. Clinical data collected included success in gaining renal access with ultrasound guidance, patient BMI, and clinical outcomes over time. Nonparametric LOWESS regression modeling was performed in R using locally weighted scatterplot smoother (R version 3.3.3) for gradations of patients by BMI group (<30, 30-40, and >40).
A total of 150 cases were examined. Case number and BMI were evaluated as continuous variables. Multivariate logistic regression revealed that BMI (P = .010; OR 0.93) and case number (P<.001; OR 1.03) were significantly correlated with ultrasound success. Sex, age, hydronephrosis, stone type, puncture location, and stone size did not influence success at obtaining ultrasound-only access in a statistically significant fashion. LOWESS regression modeling of the relationship between case number and renal access success depicts that the curve representative of the BMI >40 group is downward and right-shifted relative to the other two groups.
The learning curve for successful ultrasound-guided PCNL is impacted by patient’s BMI as well as case number. Increasing BMI makes access more challenging when performing ultrasound-guided PCNL.
Ultrasound Guidance to Assist Percutaneous Nephrolithotomy Reduces Radiation Exposure in Obese Patients
2016, Urology
Citation Excerpt :
Torrecilla Ortiz et al reported the relationship between BMI, fluoroscopic screening time, and radiation exposure dose. Their prospective study of 255 PCNLs performed with fluoroscopic guidance demonstrated that total radiation dose increases along with BMI.8 Torrecilla Ortiz et al's study demonstrated an increased radiation dose with increasing BMI despite no significant difference in total fluoroscopic screening time among the BMI groups.
To evaluate the impact of body mass index (BMI) on perioperative outcomes and radiation exposure for ultrasound (US)-guided percutaneous nephrolithotomy (PCNL).
Data were prospectively collected for consecutive patients who underwent PCNL at the University of California, San Francisco, from July 2013 to November 2015. Patients were divided into 3 groups according to their BMI: <25 (normal weight), 25-29.9 (overweight), and >30 (obese) kg/m². Perioperative outcomes were compared between patients who underwent US-guided vs fluoroscopy-guided PCNL.
One hundred thirty-five patients were enrolled; 93 cases were performed under US and 42 under fluoroscopic guidance. US successfully guided renal access in 76.9% of normal weight, 79.0% of overweight, and 45.7% of obese patients (P < .05). Mean fluoroscopic screening time and radiation exposure dose were reduced for US compared to fluoroscopy cases across all BMI categories (P < .05). As BMI increased, radiation exposure dose rose disproportionately faster compared to screening time (P < .001). No significant differences among the BMI groups were found with regard to complication rate, hospital stay, and stone-free status.
US-guided PCNL may be more difficult in obese patients, but with its use, the overweight and obese experience the largest absolute reduction in radiation exposure. Because these patients are inherently at greater risk for radiation exposure compared to normal weight patients, they may benefit the most from adoption of US for PCNL.
Radiation exposure in emergency ureteric stenting: A subgroup analysis by operator
2023, BJUI Compass
Clinical Considerations for Patients Experiencing Acute Kidney Injury Following Percutaneous Nephrolithotomy
2023, Biomedicines

View all citing articles on Scopus

: Financial Disclosure: The authors declare that they have no relevant financial interests.

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Endourology and StonesObesity in Percutaneous Nephrolithotomy. Is Body Mass Index Really Important?

Objective

Materials and Methods

Results

Conclusion

Section snippets

Objective

Materials and Methods

Results

Comment

Conclusion

Lancet

Eur Urol

Eur Urol

Br J Anaesth

Urology

J Urol

J Urol

J Urol

Eur Urol Supplem

Obesity: preventing and managing the global epidemic. Report of a WHO consultation

World Health Organ Tech Rep Ser

Guidelines on Urolithiasis. In Urology EAo: EAU Guidelines

Endourology and Stones
Obesity in Percutaneous Nephrolithotomy. Is Body Mass Index Really Important?