Does body mass index impact the outcomes of tubeless percutaneous nephrolithotomy?

Effect of Body Mass Index on Outcomes of Percutaneous Nephrolithotomy: A Systematic Review and Meta-Analysis

Objective

The current study aimed to assess the efficacy and safety of percutaneous nephrolithotomy (PCNL) in obese and overweight individuals based on body mass index (BMI).

Methods

We electronically explored the databases of PubMed, CENTRAL, ScienceDirect, Embase, and Google Scholar databases for all types of comparative studies investigating the role of BMI on PCNL outcomes. Only studies defining obesity as >30 kg/m² were included. Efficacy outcomes were stone-free rates and operating time while safety outcomes were complications and length of hospital stay (LOS).

Results

Eighteen studies with 101,363 patients were included. We noted no difference in the stone-free rates after PCNL for morbid obese vs normal BMI patients (OR: 0.78 95% CI, 0.57, 1.08 I²= 7% p = 0.13), overweight vs normal (OR: 1.01 95% CI, 0.89, 1.15 I²= 1% p = 0.83) and obese vs normal patients (OR: 1.00 95% CI, 0.87, 1.16 I²= 0% p = 0.95). PCNL operative time was significantly increased in morbid obese (MD: 9.36 95% CI, 2.85, 15.88 I²= 76% p = 0.005) and obese patients as compared with normal patients (MD: 2.15 95% CI, 1.20, 3.10 I²= 0% p < 0.00001), but not for overweight patients. There was no difference in the odds of complications between morbid obese vs normal (OR: 1.26 95% CI, 0.93, 1.72 I²= 0% p = 0.13), overweight vs normal (OR: 1.11 95% CI, 0.96, 1.28 I²= 0% p = 0.15), and obese vs normal patients (OR: 1.07 95% CI, 0.91, 1.27 I²= 0% p = 0.40). LOS was significantly reduced in obese patients (MD: −0.12 95% CI, −0.20, −0.04 I²= 0% p = 0.004) as compared to normal patients, but not for morbid obese or overweight patients.

Conclusion

PCNL has similar efficacy and safety in morbidly obese, obese, and overweight patients as compared to normal BMI patients with no difference in the stone-free and complication rates. Evidence suggests that operating time is increased in morbidly obese and obese patients and the latter may have shorter LOS.

Systematic Review Registration:https://www.crd.york.ac.uk/prospero/, identifier: CRD42022313599.

Intraoperative and postoperative surgical complications after ureteroscopy, retrograde intrarenal surgery, and percutaneous nephrolithotomy: a systematic review

INTRODUCTION

Retrograde ureteroscopy (URS), intra-renal surgery (RIRS) and percutaneous nephrolithotomy (PCNL) represent routine interventions for the treatment of ureteral and renal stones, although at times associated with serious adverse events. Of note, the evidence on perioperative complications after these procedures remains sparse and controversial. Moreover, there is a lack of standardized reporting of adverse events using uniform systems. The aim of the present study was to systematically review of the available evidence on URS/RIRS and PCNL for the surgical treatment of urinary stone, assessing the incidence of intra- and postoperative events, classified according to the modified Clavien-Dindo scale.

EVIDENCE ACQUISITION

A systematic review of the literature was performed according to PRISMA recommendations and was conducted on intra- and postoperative complications, as well as on their management, following URS, RIRS and PCNL procedures, particularly focusing on major events.

EVIDENCE SYNTHESIS

Overall, 26 studies (13 on URS/RIRS and 11 on PCNL) met the inclusion criteria and were evaluated. The highest intraoperative complication rate was 11.5% and 8.5% for RIRS and PCNL, respectively. Major complication rate following URS/RIRS and PCNL ranged between 0.3-31.7% and 2-17.1%, respectively. The most frequent adverse events were obstructive pyelonephritis or urinary leakage requiring the placement of a double J stent or a drainage. Among PCNLs series, life-threatening adverse events have also been reported, including bleeding requiring renal angioembolization and urothorax.

CONCLUSIONS

Despite the inclusion of series using a standardized reporting system, the complication rate after URS/RIRS/PCNL remains extensively heterogeneous in the literature; in addition, a non-negligible proportion of studies did not characterize the adverse events nor report the actual management strategy to solve them. Future research is needed to standardize the classification and reporting of surgical complications after endourological procedures (taking into consideration the surgeon's experience and skills), aiming to improve patient counseling and potentially the strategy for their prevention.

Skin to calyx distance is not a predictive factor for miniaturized percutaneous nephrolithotomy outcomes

Objective

To evaluate the predictive value of the distance from skin to calyx (SCD) on the outcome and complication rates of patients undergoing mPNL.

Materials and Methods

Patient’s charts, who had undergone mPNL between June 2012 and June 2015, were analyzed retrospectively. Patients who had a preoperative computerized tomography (CT) were enrolled into the study. Two separateurologists evaluated the CT scans and calculated the SCD defined as the distance between the skin and surface/lateral edge of the calyx, which was the preferred site of entry for percutaneous access. The average value of the two measurements was included inthe final analysis to avoid bias. The mean SCD was 75mm. According to the median SCD value, patients were divided into two groups: group 1 (SCD ≤75) and group 2 (SCD >75).

Results

A total of 140 patients and 130 patients were enrolled in groups 1 and 2, respectively. The mean operation time and the mean fluoroscopy time was significantly longer in group 2 (p:0.004 vs. p:0.021). The rate of blood transfusion was significantly higher in group 1 (6 patients). None of patientsin group 2required blood transfusion (p:0.017). Stone-free status after a single session of mPNL was 67.1% in group 1 and 75.4% in group 2 (p:0.112). After additional procedures, stone-free rates increased to 84.3% and 85.4% in group 1 and group 2, respectively (p:0.802).

Conclusion

Our study demonstrated that longer SCD was not a predictive factor for stone-free rates after mPNL. However, SCD over 75mm was associated with longer operation time and fluoroscopy time with lower rates of transfusion.

Comparison of STONE, CROES and Guy's nephrolithometry scoring systems for predicting stone-free status and complication rates after percutaneous nephrolithotomy in obese patients

In this study, we aim to evaluate the accuracy of STONE (stone size, tract length, obstruction, number of involved calyces, and essence/stone density), Clinical Research Office of the Endourological Society (CROES), and Guy's nephrolithometry scoring systems (NSS) in obese patients. The charts of patients who underwent percutaneous nephrolithotomy (PNL) between June 2008 and June 2016 were retrospectively analyzed. Calculations of the STONE, CROES, and Guy's NSS were performed by a resident who was well informed regarding each NSS. Patients were classified under nine scores according to STONE, four grades according to CROES, and four grades according to Guy's NSS. In total, 248 obese patients were enrolled in the study. Stone size was significantly higher in patients without stone-free status (p = 0.001). In patients who were stone-free and those with residual stones, the mean STONE score was 9.71 and 9.23 (p = 0.160), CROES was 172 and 129 (p = 0.001), and Guy's NSS was 1.67 and 2.75 (p = 0.001). Multivariate regression analysis identified the CROES and Guy's NSS were independent factors for PNL success in obese patients (p = 0.01 and p = 0.01, respectively). The CROES and Guy's NSS showed good accuracy with PNL success (AUC = 0.777 and AUC = 0.844, respectively). None of the three NSS systems were statically associated with a complication rate (p = 0.23 for STONE, p = 0.14 for CROES, and p = 0.51 for Guy's NSS). Our study demonstrated that CROES and Guy's NSS were independent predictors of stone-free rate following PNL in obese patients. Our study also revealed that three of the NSSs were not useful for predicting PNL complications in obese patients.

Totally tubeless percutaneous nephrolithotomy is feasible in morbidly obese patients

OBJECTIVE

Regarding technical difficulties that obese body habitus might impose to percutaneous nephrolithotomy (PNL) success and higher risk of peri-operative complications in this group of patients, we decided to retrospectively gather data from our patients during past 8 years to determine the stone free and complication rates.

MATERIAL AND METHODS

Between January 2007-December 2015, seventy-eight obese patients with body mass index over 35 who had indication for PNL including stones larger than 2 cm in pelvi-calyceal system or smaller extracorporeal shock wave lithotripsy (ESWL) resistant stones or who were not a fit candidate for ESWL due to increased skin to target distance, with no contraindication of PNL (including bleeding diathesis, inability to be positioned in prone) were enrolled. They were randomly assigned to group 1 (standard PNL with nephrostomy and ureteral stent) or group 2 (totally tubeless PNL with no ureteral stent and no nephrostomy). The outcomes were compared.

RESULTS

The transfusion rate, operation time, and the hemoglobin drop were same across the groups (p>0.05). Total analgesic use was equivalent of 33.8 vs. 14.7 mgs of morphine sulfate (18-77 mg) and was significantly lower in total tubeless group (p=0.001). Return to normal activity was described as total number of in-patient and outpatient days from time of admission to the point which the patients returns to normal life activity such as going to job or school and was 19.4 vs. 9.3 days (6-30 days, p=0.001).

CONCLUSION

Totally tubeless PNL in obese subjects would have lower analgesic use and return to normal activity versus standard PNL. Totally tubeless PNL is recommended for obese patients.

Ultrasound Guidance to Assist Percutaneous Nephrolithotomy Reduces Radiation Exposure in Obese Patients

OBJECTIVE

To evaluate the impact of body mass index (BMI) on perioperative outcomes and radiation exposure for ultrasound (US)-guided percutaneous nephrolithotomy (PCNL).

PATIENTS AND METHODS

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.

RESULTS

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.

CONCLUSION

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.

Effectiveness of retrograde intrarenal stone surgery in obese patients

BACKGROUND

A number of comorbid health problems can be found in obese patients. These problems increase the surgical risk in obese patients.

AIMS

To determine the effectiveness of retrograde intrarenal surgery for renal stone treatment in obese patients.

METHODS

We retrospectively reviewed the data of 106 patients who had retrograde intrarenal surgery with the diagnosis of renal stone in our clinic. The patients were divided into three groups regarding their body mass indexes: ≥30 kg/m² being obese (group 1), 25-29.9 kg/m² being overweight (group 2), and <25 kg/m² being normal weight (group 3). The patients were compared for age, gender, and stone characteristics. In addition, the duration of surgery, stone-free rate (SFR), complication rate, and the duration of the hospital stay were compared among the groups.

RESULTS

Twenty eight patients were obese (group 1), 49 patients were overweight (group 2), and 29 patients were normal weight (group 3). The mean ages of groups 1, 2 and 3 were 51.5 (29-84), 47 (30-76) and 35 (19-84) years, respectively (p = 0.001). SFR was 85.7 % in group 1, 89.8 % in group 2, and 75.9 % in group 3 (p = 0.24). The duration of surgery was similar in groups 1, 2, and 3, being 45.5 (25-95), 50 (30-120), and 45.5 (10-100) min, respectively (p = 0.23). None of the patients had major complications.

CONCLUSIONS

Our results indicate that retrograde intrarenal surgery is a safe and efficient surgical method for renal stone treatment in obese and overweight patients.