1975, British Journal of Radiology, 48, 987-992

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Percutaneous antegrade pyelography in small infants and neo nates By R. Fowler, M.D., F.R.A.C.S., and F. Jensen, M.B., Ch.B., D.D.R., M.R.A.C.R., F.R.C.R. Departments of Surgery and Radiology, Royal Children's Hospital, Melbourne, Australia (Received December 1974, and in revised form July, 1975)

ABSTRACT

Percutaneous antegrade pyelography is a safe and useful alternative to retrograde pyelography in the investigation of urinary-tract malformations in the neonate or very young infant. It is preferred to arteriography in the infant with a loin mass. Satisfactory delineation of hydronephrosis or cysts is simply and directly accomplished by this method, so that more complex and less definitive investigations can often be avoided. In addition, a variety of ureteric abnormalities may be displayed.

The limitations of radiological investigation of the urinary tract in small infants are widely recognized (Lyons et ah, 1972), especially in the diagnosis of renal masses or non-refluxing hydro-ureters. When renal function is diminished or absent, as it often is in such instances, intravenous urography (IVU) can only give inadequate information as to the degree of malformation of the pelvis or calyces, or whether ureteric dilatation is due to significant ureterovesical (UV) obstruction (Bischoff, 1957) or merely to idiopathic dilatation (Cussen, 1971). When vesicoureteric reflux is present, micturition cystourethrography automatically provides retrograde pyelograms and ureterograms, but otherwise cystoscopy and ureteric catheterization are required. Because of the technical difficulties and hazards of these operative procedures in the neonate or small infant, they are avoided as far as possible. Nephrotomography, with its increased radiation, although at times yielding some useful information, is seldom diagnostic and best avoided. Nephrosonography (Lyons et al., 1972) is a relatively new technique, for which few centres are adequately equipped, and which provides less satisfactory delineation of cysts and hydronephrosis than antegrade pyelography. Percutaneous antegrade pyelography has now become a safe and acceptable technique in the investigation of the urinary tract in adults (Lundin and Wadstrom, 1965), and has been cautiously extended to dilated ureter problems in children (Sherwood and Stevenson, 1972; Fletcher and Gough, 1973). In company with Saxton et al. (1973), we have sought to extend it into the newborn period, particularly in the diagnosis of a loin mass.

In adults, antegrade pyelography has been useful mainly in hydronephrosis, renal cysts and tumours. Tumours, fortunately, are exceptionally rare in the newborn infant; usually they are associated with displacement and distortion of functional renal tissue apparent on IVU. The main differential diagnosis of suspected renal masses in the new-born lies between hydronephrosis, multicystic kidneys and renal vein thrombosis. In the absence of infection, hydronephrosis and cystic kidneys may present without any other tell-tale clinical features, but renal vein thrombosis is recognized by accompanying haematuria and thrombocytopenia, usually with some precipitating episode marked by dehydration or infection (Belman et al., 1970; Seeler, Kapadia and Moncardo, 1970). Therefore it need not be considered further here as a diagnostic radiological problem. Antegrade pyelography is a simple and useful procedure, but there has been a tendency to resort to it only after the failure of both IVU and retrograde pyelography, sometimes following inconclusive arteriography as well. Rather than a last resort, we would, in the neonate with a loin mass, regard it as the procedure of choice after IVU. TECHNIQUE

Sedation and even local anaesthesia are usually unnecessary at this age. The infant is held by a nurse in the left or right lateral position, as for a lumbar puncture, with the insertion of a small rolled linen drape, or sterile towel, to serve as a loin kidney rest. Skin preparation and sterile draping then precedes puncture through the renal angle with an 18-gauge lumbar-puncture needle. A fingertip of the operator's free hand placed firmly in the renal angle guards the lower edge of the pleura from inadvertent puncture. This free hand grasps and steadies the loin, or any renal mass palpable, to facilitate renal puncture. A respiratory swing of the needle indicates that puncture is imminent. When the needle enters the pelvicalyceal system, or an independent cyst, a distinct "pop" is usually felt. The appearance

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R. Fowler and F. Jensen of clear fluid on withdrawal of the stilette, or on aspiration with a syringe, confirms successful puncture. Several less distinct preliminary "pops" may be experienced with passage of the needle through the separate layers of the lumbo-dorsal fascia, particularly in older children. In the neonate, the kidney is so close to the surface that this seldom presents a source of confusion, unless the tissue planes have been distorted by local anaesthetic infiltration. This is best avoided. Prior to the injection of suitable contrast medium into a tense hydronephrosis or cystic kidney, the aspiration of a few ml. of fluid is advisable. Further aspiration and contrast injection is then greatly facilitated by substitution of a 19-gauge venipuncture needle and polyethylene cannula* in place of the original lumbar-puncture needle, but this is not an essential step in the technique. The volume of contrast injected will be decided by the abnormalities outlined, as seen by fluoroscopy. Another variation of technique, only practicable in the presence of adequate contrast excretion by the kidney, is to puncture the pelvicalyceal system under direct X-ray control, with the baby in the prone position, after preliminary intravenous contrast injection. With renal masses in the new-born, however, this is seldom practicable, or necessary, but is most likely to be of help for studying hydroureters with doubtful UV obstruction by the pressure-flow method of Whitaker (1973).

FIG. 1. Casel. Plain abdominal film showing ascites and a large left-sided mass.

CASE REPORTS

Casel A female infant, born at 35 weeks gestation, after a pregnancy complicated by acute hydramnios at 32 weeks, was admitted on the first day of life with huge increasing abdominal distension, signs of ascites and some peripheral oedema of the legs. Plain abdominal radiograph (Fig. 1) showed ascites and a left-sided mass. A peritoneal dialysis catheter was inserted and ascitic fluid allowed to drain slowly overnight. After 50 ml. of fluid had drained, an ill-defined left-sided abdominal mass was felt. A voiding cystogram revealed no abnormality, but on IVU there was no detectable renal function on the left side, with a normal appearance of the right kidney. Aortography confirmed the presence of a huge soft-tissue mass in the left side of the abdomen, and displayed the right renal artery, but no discernible left renal artery. Antegrade pyelography then outlined the large renal cyst seen in Fig. 2, with some contrast also outlining a deformed calyx. At laparotomy a large cystic lesion of the left kidney was found without recognizable parenchymal tissue. Pathological examination of the excised specimen showed a large bilocular cyst, almost totally replacing the kidney, and separated by a thin shell of renal parenchyma from a normal renal pelvis and ureteropelvic junction. Partial obstruction of the inferior vena cava by the cyst seems the most probable explanation of the ascites and peripheral oedema. *"Intracath".

Comment Neonatal ascites was a most unusual presentation of a renal cyst. Once the ascites had been tapped, however, and the presence of a loin mass recognized, complex and unnecessary investigations could have been avoided by the earlier performance of antegrade pyelography. Although aortography has recently been stressed by Kyaw (1974) in the radiological diagnosis of congenital multicystic kidney, it is a procedure with recognized difficulties and dangers in the newborn period, and so not to be preferred to the much simpler technique of antegrade pyelography. Case 2 A male infant presented on the first day of life with a left-sided abdominal mass. IVU revealed no sign of left renal function, with normal appearances on the right side. Cystoscopy was undertaken on the seventh day of life, with the intention of performing left retrograde pyelography but the left ureteric orifice could not be identified. The right orifice was seen in the normal position. Antegrade pyelography then outlined the multilocular cavity shown in Fig. 3, compatible with a diagnosis of either hydronephrosis or multicystic kidney. At operation one month later a large multicystic left kidney was removed, and the baby's subsequent course has been uneventful.

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FIG. 3. Case 2. Left antegrade pyelogram showing a multilocular structure, compatible with either hydronephrosis or multicystic kidney.

FIG. 2. Case 1. Left antegrade pyelogram demonstrating a large renal cyst with some contrast medium in a deformed calyx.

Comment

An unnecessary anaesthetic and unrewarding timeconsuming cystoscopic procedure could have been avoided by first resorting to percutaneous pyelography. Case 3

One of a pair of non-identical twin girls, presented with a symptomless left renal mass. IVU (Fig. 4) showed normal appearances on the right side, but no discernible renal function on the left side. Antegrade pyelography (Fig. 5) then revealed a grossly distorted and malrotated left hydronephrosis. A dysplastic left kidney with hydronephrosis and pelvic-ureteric obstruction was subsequently removed. Comment

Profiting by earlier experience, antegrade pyelography was here the definitive diagnostic procedure, so that other unnecessary and complex investigations were avoided. Case 4

A male infant presented at age two weeks with neonatal septicaemia. Urine obtained by suprapubic bladder aspiration showed infection with E. coli, which cleared following appropriate antibiotic treatment. IVU then revealed left hydronephrosis and hydroureter, with possible UV obstruction. There was no vesicoureteric reflux or other abnormality seen on micturition cystourethrography.

Antegrade pyelography (Fig. 6) delineated more clearly the full extent of the ureteric abnormality and provided unequivocal evidence of UV obstruction by gross delay in emptying. Operation later disclosed a "tilt-valve" type of obstruction (Bischoff, 1957) of the juxta-vesical ureter, which was relieved by extravesical uretero-ureteroplasty. Comment

An unnecessary preliminary endoscopic procedure and general anaesthetic was avoided. Case 5

A female infant presented at three days of age with severe urinary tract infection and a left upper abdominal mass. IVU (Fig. 7) showed a hydronephrotic left renal segment with a reduced number of calyces and a filling defect in the bladder. Micturition cystourethrography revealed reflux into a left orthotopic mega-ureter and dilated pelvicalyceal system. There was also a filling defect consistent with a left-sided ectopic ureterocele. Neither the IVU nor MCU revealed the ectopic ureter or upper polar renal segment. Cystoscopy confirmed the presence of a leftsided ureterocele, but neither of the left ureteric orifices were found. Antegrade pyelography using a 19-gauge "Intracath" venipuncture catheter then succeeded in filling the pelvis of the previously undetected upper pole, together with the ectopic ureter and associated stenotic ureterocele (Fig. 8).

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FIG. 4. Case 3. Intravenous urogram showing no function in the left kidney even at two hours.

FIG. 5. Case 3. Left antegrade pyelogram revealing a grossly-distorted and malrotated hydronephrotic left kidney.

Following heminephrectomy and ectopic ureterectomy, the function of the left lower renal segment did not improve significantly, and urinary infection recurred frequently. Total left nephroureterectomy was then completed, and at a subsequent transvesical operation the stenotic ureterocele was excised.

An important additional application is in those cases of suspected UV obstruction where sufficient renal function remains for the abnormal structures to be outlined on IVU. The diagnostic dilemma is then to determine whether this upper tract dilatation is due to significant obstruction at the UV junction, or simply a developmental anomaly without any serious long-term implications for obstructive damage to the kidney (Cussen, 1971). Retrograde catheterization to assess emptying times may only accentuate this dilemma by causing artefactual hold-up of contrast medium at the UV junction. Even the smallest ureteric catheter available can still cause appreciable oedema of an infant's ureteric orifice, with iatrogenic delay in ureteric emptying. Percutaneous renal puncture avoids this by not interfering with the UV junction itself, and delay in ureteric emptying wiH provide unequivocal evidence of UV obstruction, as in Case 4. More borderline

Comment A complex surgical plan was greatly facilitated by precise and complete delineation of the left double ureter system, stenotic ureterocele and associated hydronephrosis. This information was virtually impossible to obtain by any other means than antegrade pyelography. DISCUSSION

The main application of this technique lies in the delineation of abnormal structures more precisely and readily than is possible by other radiological or urological investigation. This is so especially in the diagnosis of congenital hydronephrosis and multicystic kidney, the two commonest causes of a loin mass in infancy.

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FIG. 8. Case 5. Left antegrade pyelogram showing a large hydronephrotic left ectopic segment, left ureter and ureterocele.

FIG. 6. Case 4. Left antegrade pyelogram demonstrating that the left hydronephrosis and hydroureter was due to a ureterovesical obstruction.

FIG. 7. Case 5. Intravenous urogram showing a left hydronephrotic renal segment, with a reduced number of calyces, and a negative filling defect in the bladder.

cases require supplementary functional evidence of obstruction (Whitaker, 1973). Serious complications resulting from percutaneous puncture of these newborn kidneys have not occurred thus far. Transient macroscopic haematuria for 12-24 hours has been observed in two children—a neonate and one older infant—but was never a serious source of concern. Urinary extravasation, even in obstructive lesions, has not presented any problem, so we have not routinely adopted the continuing percutaneous needle catheter drainage technique developed by Cobb (1967) and others (Saxton, Ogg and Cameron, 1972). In summary, we believe that this is a simple, safe and effective technique which will have an increasing application in the field of paediatric urology, particularly if used electively rather than as a procedure of last resort. We have not attempted antegrade pyelography in the presence of uncontrolled urinary infection or any clinical suspicion of renal vein thrombosis, regarding either of these as contraindications to the procedure. REFERENCES BELMAN, A. B.,

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F.,

BURDEN, J. J.,

and

KAPLAN, G. W., 1970. Non-operative treatment of unilateral renal vein thrombosis in the newborn. Journal of the American Medical Association, 211, 1165-1168.

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Nephrosonography in infants and children: a new tech-j BISCHOFF, P., 1957. Megaureter. Britishjournal of Urology, 29, nique. British Medical Journal, 2, 689-691. 416-423. COBB, B., 1967. Silverman needle nephrostomy. Journal SAXTON, H. M., OGG, C. S., and CAMERON, J. S., 1972. Needle nephrostomy. British Medical Bulletin, 28, oj Urology, 98, 309-313. CUSSEN, L. J., 1971. The morphology of congenital dilata210-213. tion of the ureter: intrinsic ureteral lesions. Australian and SAXTON, H. M., CAMERON, J. S., CHANTLER, C , and OGG, New Zealand Journal of Surgery, 41, 185-194. C. S., 1973. Renal puncture in infancy. British Medical FLETCHER, W. L., and GOUGH, M. H., 1973. Antegrade Journal, 2, 267-270. pyelography in children. British Journal of Radiology, 46 SEELER, R. A., KAPADIA, P., and MONCARDO, R., 1970. 191-194. Nonsurgical management of thrombosis of bilateral KYAW, M. M., 1974. The radiological diagnosis of conrenal veins and inferior vena cava in a newborn infant. genital multicystic kidney. "Radiological triad" Clinical Clinical Pediatrics, 9, 543-547. Radiology 25, 45-62. SHERWOOD, T., and STEVENSON, J. J., 1972. Antegrade pyelography: a further look at an old technique. British LUNDIN, E., and WADSTROM, L. B., 1965. Translumbar pyelography. Ada chirurg Scandinavia, 130, 267—278. Journal of Radiology, 45, 812-820. LYONS, E. A., FLEMING, J. E. E., ARNEIL, G. C , WHITAKER, R. H., 1973. Methods of assessing obstruction in dilated ureters. Britishjournal of Urology, 45, 15-22. MURPHY, A. V., SWEET, E. M., and IAN DONALD, 1972.

Book review Current Concepts in Radiology. Vol. 2. Edited by E. James Potchen, pp. 328, 354 illus. 1975 (St. Louis, C. V. Mosby Co.; distributed in Britain by Henry Kimpton, London), £16-60. In this second volume of a series, there are four chapters on departmental organization and the use of radiology, three on X-ray imaging and four on selected advances in clinical radiology. The book is dedicated to "radiologists of the future", but even creaky radiologists of the present will probably enjoy reading it. The first four chapters, dominated by information and communication theory, are naturally full of forbidding, abstract words: one expects systems, inputs and outputs in this setting, but topics like entropy minimax analysis might just throw some readers. It would be wrong to conclude that these chapters are only highflown stuff irrelevant to the busy, practical radiologist. The very first diagram is a down-to-earth study of when outpatients actually arrive for their booked appointments (a third never turn up at all). This chapter - "Operations management in radiology"— is probably essential reading for those radiologists planning new departments, and full of general interest on organizational matters. "Study on the use of diagnostic radiology", "Analysis of decisions and information in patient management", and "Studies on the use of the intravenous pyelogram" are the titles of the remaining chapters in this section. Parts of these are highly

mathematical or theoretical, but all are at least practical in intention: to make better use of X-ray departments by patients and doctors. The three middle chapters discuss electronic imaging, "receiver operating characteristics", and chest X-ray technique. Endeavours toward better X-ray images are of course interesting, if often expensive. How about attention to that most variable and also cheaper cog in the system, film processing and its control ? The last chapters are on special procedures in pulmonary radiology, asbestosis, frontiers in gastro-intestinal radiology, and emergency nuclear medicine. These are necessarily rather arbitrary selections of recent advances from a large field. The approach is comprehensive: for instance, the first of these chapters deals with lung fluoroscopy, tomography and bronchography before moving on to brush and needle biopsy. A cheaper, perhaps paperback presentation of this sort of series might have been attractive for the radiologist's own bookshelf. As the volume has all the trappings of the expensive text-book, rather special enthusiasm for mixed collections of radiological writing would probably be needed toward individual purchase. Large libraries may find it useful for plugging gaps in the storehouse of radiological information.

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