RADIOLOGY MCQ--Yo-Yo reflux and Weigert-Meyer law

Yo-Yo reflux  and Weigert-Meyer law

Q1.Yo-Yo reflux is noted in

a.incomplete duplication of pelvis

b.hydronephrosis

c.ectopic insertion of ureter

d.crossed fused ectopia

Q2.Weigert-Meyer law is related to 

a.incomplete duplication of pelvis
b.duplex collecting system with incomplete duplication of ureter
c.duplex collecting system with complete duplication of ureter
d.complete duplication of ureter only

ANS.1==a==incomplete duplication of pelvis
        2==c==duplex collecting system with complete     duplication of ureter

www.urology-textbook.com 

•  Duplication of the upper collecting system is one of the most common of  renal anomalies
• Complete duplication is associated with ectopic ureter, ureterocele or vesicoureteral reflux. 
•  The incomplete duplication of the upper collecting system rarely causes urinary symptoms and usually does not carry clinically importance 
•  Reflux of the urine from one limb of the collecting system to the other limb, rather than down towards the bladder  is called yo-yo reflux (saddle reflux) 
•  Cause : Disorders in ureteric peristalsis at the site of ureteric fusion may cause yo-yo reflux.
•  Another explanation of yo-yo reflux is the pressure gradient between two ureteric  segments. The pressure of the lower moiety is generally  higher than the upper moiety and therefore the urine  generally refluxes from the lower moiety to the upper moiety 

Weigert-Meyer law

• Weigert-Meyer law applies to duplex collecting systems, when complete, duplicated ureters insert separately into the bladder.
•  The Weigert-Meyer rule states that. the upper pole ureter is the ectopic ureter and its orifice inserts inferomedially in the bladder in relationship to the lower pole normal ureter 
• When duplicated ureters insert separately into the bladder, the laterocranial ostium corresponds to the caudal renal pelvis and the medio caudal ostium the cranial renal pelvis.