12

Practical Urology: EssEntial PrinciPlEs and PracticE

Logically, in the male, the vesical neck and pros-

intravesical ureter, produces the characteristic

tatic urethra are most commonly involved. The

urographic “cobra head” or “spring onion” fill-

ejaculatory ducts should theoretically be next in

ing defect. A second classical finding is the halo

line, but they are uncommonly involved in view

or negative shadow effect which surrounds the

of the very short segment of the original meso-

cystic outline of the ureterocele filled with con-

nephric duct which gives rise to this structure.

centrated contrast media (see Figs. 1.8 and 1.9).

Therefore, the seminal vesicles are next in fre-

In review, as stated previously, ureteroceles

quency and the vas deferens follows.

are often but not always associated with ureteral

Rectal positioning of the ureter is rare and

duplication. However, if duplication is present,

can be explained embryologically by a very dor-

the ureterocele is always associated with the

sal entry of the original pronephric duct into the

ureter serving the upper segment of a dupli-

cloaca, or by erroneous anterior division of the

cated kidney that is the ureter which enters in

cloaca by the urorectal septum, so that the divi-

the lower and more dense and medial position

sion occurs ventral to the point of pronephric

of the bladder. Furthermore, the ureter from the

duct entry.

lower renal segment – that is the ureter which

empties into the more cephalad and lateral

Symptoms

position of the bladder may be compromised by

a ureterocele and thus also be obstructed and

Symptoms related to ureteral ectopia are thus

may reflux because of its position off the

trigone.

dependent upon the site of the ureteral opening

A final point. Because ureteral duplication is

and the patient’s sex. Inasmuch as the ectopic

more common in females than males, uretero-

orifice always opens proximal to the external

celes are also more common in females and

sphinctor in the male, incontinence should not

when encountered in children, whether male or

really ever occur. However, in the female, incon-

tinence is a common complaint since the ure-

teral orifice is located distal to the sphinctor

mechanism in the majority of cases. Ectopic

ureters entering the bladder on the lower trig-

one are usually associated with a ureterocele

because of partial obstruction. Furthermore, in

either sex, the ectopic ureter, because of obstruc-

tion is almost always associated with uretral

dilatation which can be so severe that the upper

renal segment becomes very hydronephrotic

and eventually non-functioning.