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A big upper-pole stone with unexpected duplicated ureters with retrocolon

A 27-year-old woman with ultrasonographically detected bilateral renal stones was referred to SMG-SNU Boramae Medical Center to get a 2nd opinion. She underwent a health check-up in a local clinic and identified bilateral large stones for the first time in her life. She had no lower urinary tract symptom except mild degree of daytime frequency. She complained of intermittent mild degree of flank discomfort but no history of fever or hematuria was identified. Physical examination was unremarkable and no CVAT (costovertebral angle tenderness) was shown.

Interesting thing is that we coudn't assume that there was any abnormality of kidney anatomy by analyzing these preoperative CT images. For sure, I knew the presence of retrocolon and HU 1,560 with stone size (18x16x14mm). When I performed RIRS for retrieval of this stone, I met some difficult situations as follows;

# Upper anterior stone

  • acute angle from upper major calyx to upper anterior redundant space (downward deflection and only pop-dusting from surface to core)

  • anticipation of scope damage: Lithovue used

# Narrow ureter to upper moiety (tightness with 7.7Fr lithovue)

  • Fragmentation technique: not available

  • As operative times goes, mucosal edema develops and difficulty increases with re-insertion to the space and risk of ureter damage

  • Only pop-dusting technique is available with least number of re-insertion

# Retrocolon

  • Available space is only 10mm between colon and psoas muscle

  • Psoas muscle is ok? Bleeding? Nerve injury?

# Very hard stone of HU 1,560 maximal diameter of 19mm

  • Fragility of 200 micrometer laser fiber and increased risk of scope damage

  • Longer operative time with increased high energy setting and risk of laser fiber damage such as burn-back, fiber breakage.

Now, what is your option among prone PCNL (maybe ultramini-PCNL), supine mPCNL and RIRS? These two pictures are showing my thoughts to solve the problem, althogh I removed all the stones by performing RIRS. Let's discuss this case and technical tips later if we have an opportunity in a conference.

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