Postgrad Med J: first published as 10.1136/pgmj.40.462.179 on 1 April 1964. Downloaded from POSTGRAD. MED. J. (I964), 40, 179 INTRAMURAL URETER AND URETEROCELE Alex Simpson Smith Memorial Lecture delivered at The Hospitalfor Sick Children, London, W.C.i July 2, I963 F. DOUGLAS STEPHENS, D.S.O., M.S.(Melbourne), F.R.A.C.S. Royal Children's Hospital Research Foundation, Melbourne, Australia DURING the past ten years much research has been scopy lends support to this theory of action. The directed to the study of the structure and function orifice, in its resting state is a pit, slit, or falciform of the normal intramural part of the ureter. The crescentic opening. Its walls and roof are ap- anatomy of the uretero-vesical 'lock' mechanism proximated to the floor thus shutting the lumen of both the normal and abnormal variants of this from view. During expulsion of urine the ureteric part of the ureter is now more clearly understood. orifice is expanded by the force of the jet, tem- It is proposed to describe the short, the long, and porarily opening the lumen to view. After the the structurally abnormal intra-mural ureters, jet has ceased, sudden transitory contraction of together with the physiological defects which they the longitudinal muscle jerks back the rim of the involve and which provoke clinical problems. orifice, hurriedly occluding the lumen and re- setting the flap valve. The muscle then slackens The Normal Intramural Ureter to its tonic resting state. The muscle longitudinal by copyright. The intramural ureter comprises that part of the animates and quickens the action of the flap valve. ureter which lies within the bladder from its point Moreover obstruction of the urethra causes of entry in the lateral wall to the orifice in the hypertrophy of the muscle of the intra-mural trigone. At first the ureter lies in the muscular ureter, thereby strengthening its walls and main- tunnel of the bladder and there it rests on the taining efficiency in the uretero-vesical valve. muscle of the bladder under the vesical mucosa. The severest urethral obstruction will not impair Its length is variable, being only 4 to 6 mm. long the valve action provided that this segment of the in the infant and io to i9 mm. in the adult ureter is normal in its structure. (Hutch, I962). The intramural ureter is slightly narrower in The Abnormal Intramural Ureter http://pmj.bmj.com/ calibre than the extra-vesical ureter. Its muscle Numerous defects of the intramural ureter occur coat differs in that it is composed of longitudinally and impair its function. A defective ureter may arranged muscle bundles only. The circular be too short, too long, too wide, abnormal in component of the extravesical ureter, which is its structure, or associated with a diverticulum or a most conspicuous layer, is not continued into the ureterocele. wall of the intramural ureter. The longitudinal muscle fibres of the roof of (a) The Short Intramural Ureter on September 23, 2021 by guest. Protected the intramural ureter insert into the rim of the Absence in whole or in part of the submucosal orifice but the muscle of the floor of the ureter is segment is a common occurrence; the deficiency prolonged into the trigone, where it is tethered. is more easily recognized when it is unilateral and The function of the uretero-vesical valve, for the opposite side is available for comparison. The reasons described elsewhere, is believed to depend orifice of the short ureter issues into the bladder on an intrinsic muscular mechanism of the intra- more laterally, with result that the trigone reaches mural ureter (Stephens ana Lenaghan, I962). out towards the lateral wall of the bladder at the The eccentric tethering of the longitudinal muscle expense of the submucosal segment. Deficiency causes the roof and walls to press back upon in length of the submucosal ureter entails a cor- the floor. This action is enhanced by intra- responding reduction in its musculature and there- vesical hydrostatic pressures. The mechanism is fore in its efficiency. thus an activated flap valve, which is dependent on muscle for its activation, and obliquity of course (b) Abnormal Structure of the Intramural Ureter for its flap valve action. The formation of muscle within this segment Inspection of the orifice of the ureter at cysto- may be impaired. Defects of the muscle may take Postgrad Med J: first published as 10.1136/pgmj.40.462.179 on 1 April 1964. Downloaded from -18 POSTGRADUATE MEDICAL JOURNAL "April I964 -the form of wedge or patchy deficiencies in the curred; if contiguous, reflux was limited to the :roof and walls. These may extend for a short or lower reach of the ureter. long distance, may perhaps involve the whole Diverticula result from deficiencies in the length of the intramural ureter, and may occur bladder muscle and exhibit a particular predilec- in an intramural ureter of the congenitally short tion for the zone near which the ureters enter the type ((a) above). The effect is to render the flap bladder. valve inactive. Histological examinations of these zones reveal Furthermore, intramural segments of ortho- that ureters with orifices contiguous with diverti- topic and ectopic components of double ureters cula exhibit patchy deficiency of muscle in their may be affected in the same way. walls, whilst the engulfed ureters are almost Appearances of the Impaired Valve. The orifice totally deficient in muscle. The defect in com- of the defective ureter is then patulous, flaccid, mon between the diverticulum and the ureter is sluggish or immobile, or lies patent exhibiting ir- muscle deficiency which accounts for the vesical regular contractions. When the intramural channel bulge on the one hand and for vesico-ureteral is short, the orifice presents an appearance to the reflux on the other. cystoscopist similiar to that of a sloping tunnel The ureter with orifice adjacent but not con- entrance, and when the submucosal segment is tiguous with that of the diverticulum is com- absent, the ureteric orifice resembles the entrance petent, its muscle being adequate, though not to a rock face tunnel, vertical and sheer. always complete in its distal roofing. The The phenomenon of vesico-ureteral reflux is presence of the diverticulum however, vicariously often associated with megaureter, which is pre- elongates the intramural ureter, and thus presents sumed to be an additional malformation (Stephens, sufficient of the muscularized segment to the side- I963a). The ureteric orifice may then be cor- on position so essential to flap-valve function. respondingly enlarged and may often be readily It is concluded that the chief factor which recognized as such by cystoscopy. impairs the action of the uretero-vesical valve is When these conditions prevail, the flocculent the lack of the muscular component of the intra-by copyright. material in the urine can be seen to undergo a mural ureter. to-and-fro movement in and out of the orifice. In addition to congenital muscular defect, This two-way flow can be confirmed by fluoro- acquired conditions such as inflammation or spinal scopy. Some ureters exhibit reflux early, others trauma may result in impaired action of the muscle. late in the period of filling of the bladder, others Pyogenic or tuberculous infection involving the again only during micturition. muscle of the ureter may inflict temporary or The two-way flow of vesico-ureteral reflux permanent damage on the uretero-vesical valve, promotes stasis, and stasis is the fore-runner of and ureteritis, as distinguished from cystitis, may infection. initiate or exaggerate reflux. Injuries of the spine http://pmj.bmj.com/ For many patients, especially those exhibiting not uncommonly provoke reflux, and though the megaureter in association with reflux, the elimina- mechanism is not fully understood, it seems tion of stasis may be effected by the simple, regular probable that the innervation of the muscle is faithful practice of multiple micturition (Stephens rendered defective. i963b). It is indeed fortunate that such a simple trick of micturition can be invoked to prevent the (d) The Long Intramural Ureter infection which so commonly supervenes on im- The long intramural ureter lies within the pairment of valve function, an impairment which wall of the bladder and sometimes extends beyond on September 23, 2021 by guest. Protected depends upon defects of its muscle component. the confines of the bladder into the wall of the Furthermore, provided infection is eliminated urethra and vagina. All such described in this by such a method it is safe to await spontaneous lecture are ectopic members of double ureter improvement or cessation of reflux such as was systems. The anatomical course of this part of an found to occur in two-thirds of the ureters of a ectopic ureter, the changes in structure and the series of 32 patients who were observed for periods atiology of ureteroceles, are pertinent to the of five to ten years. theme of this paper. (c) Paraureteral Diverticula Course of Ectopic Ureter When a ureter lies in proximity to a vesical The ureter which issues from the caudal segment diverticulum vesico-ureteral reflux may occur. In of the kidney is called orthotopic because it opens the series of patients studied, it was possible to into the bladder in the usual situation. That make a generalisation, namely, that if the urethral which drains the cranial segment is the ectopic orifice lay within the diverticulum reflux was free. ureter. It terminates at an ectopic site, either in If the two orifices were separate, no reflux oc- the orthotopic ureter or in the trigone, urethra Postgrad Med J: first published as 10.1136/pgmj.40.462.179 on 1 April 1964.