Outcomes of Flank-Free Modified Supine Percutaneous Nephrolithotomy Based on BMI

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.

Double-Sheath Vacuum Suction Minimally Invasive Percutaneous Nephrolithotomy for Management of Large Renal Stones

OBJECTIVES

This study aimed to describe a novel double-sheath vacuum suction minimally invasive percutaneous nephrolithotomy (mini-PCNL) to overcome the deficiencies of the conventional procedure.

PATIENTS AND METHODS

Between March 2019 and December 2019, 65 patients (37 males and 28 females) with a mean age of 41 years (range 23-69) underwent mini-PCNL with double-sheath vacuum suction. It consisted of an F20 Y-shaped sheath as an outer sheath and an F16 Y-shaped sheath as an inner sheath, in which the inner sheath was longer than the outer sheath. The oblique arm of the outer sheath and the inner sheath was connected to the perfusion inflow and the vacuum suction, respectively. A 550-μm holmium-YAG laser was introduced for stone fragmentation through the working channel of the mini-nephroscope, which was no longer connected to the perfusion fluid.

RESULTS

All procedures were successful. Mean operation time was 50.2 min (range 39-83). Mean hemoglobin decrease was 5.2 g/L (range 1.0-15.5), and no patient needed a blood transfusion. One patient (1.5%) with low fever (<38°C) at day 1 had returned to normal at day 2 without administration of antibiotics. There were no Clavien grade 2-4 complications. Mean postoperative hospital stay was 2.4 days (range 2-6). The initial stone-free rate of PCNL was 81.53% (53 of 65 patients). One month after surgery, the final stone-free rate increased to 90.77% (59/65 patients).

CONCLUSIONS

The double-sheath vacuum suction mini-PCNL is a safe and effective modality for large renal stones, which might increase the efficiency of stone extraction with low intrapelvic pressure.