The Appearance of Medullary Sponge Kidney on Retrograde Intrarenal Surgery: Video Article

Introduction

The medullary sponge kidney (MSK) is a kidney development disorder that is known for the cystic dilation of the pyelocalyceal system and diffuse pelvicalyceal ectasias. These dilations which are called “stone nests” are usually between 1 and 7 mm in size, and often contain small stones. MSK is a rare disease, with a prevalence of 5 in 10000 people. Based on the evidence, MSK is observed in 12-20% of the urinary calculi population. On the other hand, over 70% of MSK patients get involved in nephrolithiasis. This disease is naturally bilateral and involves multiple kidney pyramids. The patients are generally asymptomatic, and the diagnosis is mainly after the occurrence of complications, like loss of urine concentration, pyelonephritis, or renal tube acidosis. The most usual symptoms included renal colic, hematuria, or fever (1-3). This article aims to show the pyeloscopic appearance of this disease during retrograde intrarenal surgery.

Case presentation

This video article is about a 45-year-old man, who presented with right flank pain, hematuria, and recurrent urinary infections. The procedure was started with ureteral access sheet placement with our previous reported zero radiation technique (4). The operation was started by using a semi-rigid 9.8 Fr ureteroscope (R. WOLF, Vernon Hills, IL), a guidewire was inserted in the kidney pelvis under direct vision as the safety wire. An access sheath (36 cm, Navigator 11.13 F, Boston Scientific, Natick, MA) without the obturator was passed over the ureteroscope, and the operation was continued by a safety wire. Access sheet was inserted under direct endoscopic vision. Then a guidewire was inserted into the kidney pelvis and the flexible ureteroscope was placed on the upper ureter. Our first point was superior calyx, then lithotripsy was done through 200-micron Holmium laser fibers (EMS holmium laser lithotripter, 0.8–1.2 J, 8–12 W). We performed the dusting and fragmentation technique rather than fragmentation. The use of an irrigation pump (WOLF) would allow us to have better vision and continuous irrigation which was set on 110–145 mmHg. Due to the length of the first session, we planned to have another one. So, we put a double-j stent and terminated the procedure. The second session has the same manner, and at the end of that, a systematic pyeloscopy was performed to make sure that all calyxes were cleaned. Operative times in the first and second sessions were 100 min and 80 min, respectively. The patient had a straight recovery and was discharged on the second postoperative day. At the 3-month follow-up visit, both kidneys were at normal without obvious stone in the kidney ureter bladder X-ray.

Conclusion

In this video, we presented the endoscopic appearance of MSK during laser lithotripsy and the follow-up pyeloscopy.

Authors’ contributions

Not applicable

Acknowledgments

Special thanks to the Urology Research Center, Tehran University of Medical Sciences, Tehran, Iran. Especially, Dr. S.M.K. Aghamir performed this interesting operation.

Conflict of interest  

The author declares that they have not known competing for financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Funding 

There is no funding.

Ethical statement

Written informed consent was obtained from the patient for the publication of their case.

Data availability

Data will be provided on request.

Abbreviations

MSK   Medullary sponge kidney