Mean Differential Function Research Articles

Dilatação Endoscópica de Balão para Tratamento de Megaureter Obstrutivo Primário: Experiência de um Centro

Introdução: O megauretero obstrutivo congénito pode ser tratado por dilatação endoscópica com balão, especialmente nas crianças com menos de um ano de idade. Este trabalho revela a nossa experiência num período de seis anos.
 Doentes e métodos: Todos os doentes com o diagnóstico de megauretero obstrutivo congénito submetidos a dilatação endoscópica com balão foram incluídos, no período de tempo compreendido entre 2009 e 2014 (seis anos). O diagnóstico baseou-se na identificação de dilatação do uretero distal superior a 7 mm, padrão obstrutivo no renograma MAG3 e ausência de refluxo vesico-ureteral. Após o diagnóstico, adoptou-se uma atitude conservadora com início de profilaxia antibiótica e vigilância ecográfica em todos os doentes. A indicação cirúrgica resultou de um conjunto de achados clínicos, ecográficos e renográficos. Sob anestesia geral, e após pielografia retrógrada, foi realizada dilatação endoscópica da junção uretero-vesical sob visão directa e controlo fluoroscópico até ao desaparecimento do anel estenótico, colocando-se no final um stent duplo J. O seguimento foi feito com controlo ecográfico e renograma. O sucesso da intervenção cirúrgica foi definido como uma melhoria no grau de hidroureteronefrose (pelo menos 2 graus).
 Resultados: No total, 9 doentes foram intervencionados num só uretero, duas meninas e sete meninos, com idade média de 7.6 meses (entre 1-14) na data da cirurgia. Cinco foram no lado esquerdo e quatro no lado direito. Todos os doentes tinham diagnóstico pré-natal de hidroureteronefrose. Nenhum doente foi perdido no seguimento (média 46.7 meses). Todos tinham hidroureteronefrose de grau superior ou igual a 3 e padrão obstrutivo no renograma MAG3. A função relativa média do rim homolateral foi 46.2% (entre 40-53%). A principal indicação cirúrgica foi o agravamento da hidroureteronefrose durante a vigilância ecográfica. Não existiram complicações intra-operatórias. A ecografia mostrou melhoria da hidroureteronefrose em 6 doentes (66.7%). Três doentes foram re-implantados (33.3%) A função relativa média após a cirurgia foi 47.4% (entre 41-53%). Na consulta de seguimento mais recente, todos os doentes estavam assintomáticos.
 Discussão: A dilatação endoscópica com balão é uma opção na abordagem do megauretero obstrutivo primário com indicação operatória e pode ser considerado como tratamento de primeira linha nas crianças com menos de um ano de idade.

Ureteropelvic Junction Obstruction Secondary to Crossing Vessels—To Transpose or Not? The Robotic Experience

We compared the surgical outcomes of robot assisted laparoscopic dismembered pyeloplasty in patients presenting with anterior crossing vessels with and without transposition of the crossing vessel. A total of 107 patients with ureteropelvic junction obstruction underwent robot assisted laparoscopic dismembered pyeloplasty. Evaluation of surgical success was based on validated pain scores, diuretic renography and imaging results, including excretory urography, computerized tomography or ultrasound. Anterior crossing vessels were identified in 48 patients (44.9%) and vessels were transposed in 18 (37.5%) (group 1). No transposition was performed in 30 patients (62.5%) (group 2). Mean radiological followup was 52.9 weeks in group 1 and 65.3 weeks in group 2 (p = 0.181). Mean pain score on a scale of 10 was 0.82 in group 1 and 0.74 in group 2 (p = 0.917). A Whitaker test performed in 3 patients with persistent pain was negative. Preoperatively mean differential function on the affected side was 35.1% in group 1 and 36.9% in group 2 (p = 0.133). Half-time was calculated as a mean of 46.3 minutes in group 1 and 49.4 minutes in group 2 (p = 0.541). In groups 1 and 2 mean postoperative differential function improved to 41.1% and 40.9%, and mean half-time improved to 7.43 and 8.03 minutes, respectively (p = 0.491). A comparison of preoperative and postoperative differential function, and half-time in each group showed a statistically significant difference. The radiographic and symptomatic success rate was 100% with no open conversion and recurrence. Comparison of robot assisted laparoscopic dismembered pyeloplasty outcomes revealed similar success rates in terms of the change in symptoms and renal function in patients with or without anterior crossing vessel transposition. Transposition of crossing vessel should only be performed when the anatomical relation dictates and it should be an intraoperative decision.

Normal appearances of technetium-99m dimercaptosuccinic acid in children on planar imaging.

Thirty-two children who underwent renal arteriography with normal results also underwent technetium-99m dimercaptosuccinic acid (DMSA) imaging. Variations in the normal appearance of 99mTc-DMSA images are described in these children. Criteria for high-quality 99mTc DMSA images are defined in terms of kidney outline and contrast between the inner and the outer part of the kidney. Most of the images in this study were of high quality. The two most common features of normal 99mTc-DMSA images were a round-shaped (50%) or flat (either lateral or medial aspect) (24.8%) contour. A small number of unusual appearances were observed and these have been illustrated. The mean differential function of the left kidney was 51% with a range of 45%-57%.

Functional results of pyeloplasty in patients with ante‐natally diagnosed pelvi‐ureteric junction obstruction

To assess the outcome after pyeloplasty in children with an ante-natal diagnosis of hydronephrosis, shown on post-natal renography to be due to pelvi-ureteric junction (PUJ) obstruction, and in particular to review the outcome of those who had initially been managed expectantly. Between 1984 and 1995, 321 patients were diagnosed as having PUJ obstruction, after investigating ante-natal hydronephrosis. Of these, 47 had undergone pyeloplasty and also had a normal contralateral kidney; 26 patients had early pyeloplasty because of impaired function and 21 underwent surgery after a period of expectant management. Renal function was assessed renographically before and at least one year after surgery. Relative renal function was stabilized in those patients who underwent early pyeloplasty (mean differential function 28.1% before and 32.7% after surgery). In patients who underwent pyeloplasty after a period of expectant management, the mean relative function decreased from 44.8% initially to 30.5% before surgery; this recovered to 37.5% at the post-operative reassessment, representing a statistically significant loss of function (P < 0.01). In patients born with PUJ obstruction and impaired renal function, pyeloplasty failed to significantly improve function. Possibly because of cortical loss. In patients with ante-natal PUJ obstruction managed expectantly there is a small but significant risk of a modest loss of renal function.

Fetal pelvi-ureteric junction obstruction: predictors of outcome.

To examine the relationship between pre-natal ultrasonographic findings typical of pelvi-ureteric junction (PUJ) obstruction and post-natal renal function in the affected kidney. This retrospective study comprised 35 infants in whom pre-natal ultrasonography had identified a unilateral pattern of dilatation of the renal pelvis and calices typical of PUJ obstruction. In each case, the presence of unilateral hydronephrosis had been confirmed post-natally by ultrasonography, and differential function and drainage evaluated by isotope renography. The results of isotope renography were compared with the severity and timing of onset of the fetal hydronephrosis. Eleven kidneys (31%) appeared normal in the second trimester and dilatation only became apparent during the third trimester. Mean differential function in these kidneys was 48%. However, mean differential function was reduced (mean 38%) in those kidneys noted to be dilated between 16 and 24 weeks gestation. Differential function was loosely correlated with the severity of dilatation in early onset cases, i.e. the mean differential function was 42% for mild, 37% for moderate and 27% for severe dilatation. A considerable variation in differential function values was present in each group except for those with severe dilatation, which was a significant predictor of poor functional outcome when compared with mild and moderate dilatation combined (P < 0.01). Fetal PUJ obstruction is a heterogeneous condition permitting only broad predictions of functional outcome. Severe dilatation detected on second trimester imaging predicted significant loss of function. Mild and moderate degrees of dilatation were associated with a one in three risk of functional impairment in the obstructed kidney.

Renal Histological Changes Secondary to Ureteropelvic Junction Obstruction

The treatment of children with apparent ureteropelvic junction obstruction is controversial. In an asymptomatic infant or child the decision to recommend pyeloplasty usually is based on interpretation of the renal scan. We retrospectively analyzed the renal biopsy obtained during pyeloplasty in 55 children. Histological changes were compared to the differential renal function revealed on the preoperative renal scan. Histological changes were graded on a scale of I to V; I--normal, II--mild dilatation of the collecting tubules or Bowman's space and III to V--progressively severe changes of obstructive uropathy, including reduced glomerular number, glomerular hyalinization, cortical cysts and interstitial inflammation. Patient age ranged from 4 days to 19 years (mean 4.8 years). Mean differential function according to histological grade was I--49%, II--43%, III--42%, IV--30% and V--25%. Of 33 patients with a differential function of 40% or greater 26 (79%) had a grade I or II biopsy, while 21% had a more significant alteration in renal histology. In contrast when the differential function was less than 40% 6 of 18 patients (33%) had grade I or II disease on biopsy. In conclusion, in approximately 25% of children with ureteropelvic junction obstruction there is a disparity between preoperative differential renal function computed during diuretic renography and renal biopsy.

Renal Histological Changes Secondary to Ureteropelvic Junction Obstruction

The treatment of children with apparent ureteropelvic junction obstruction is controversial. In an asymptomatic infant or child the decision to recommend pyeloplasty usually is based on interpretation of the renal scan. We retrospectively analyzed the renal biopsy obtained during pyeloplasty in 55 children. Histological changes were compared to the differential renal function revealed on the preoperative renal scan. Histological changes were graded on a scale of I to V: I–normal, II–mild dilatation of the collecting tubules or Bowman's space and III to V–progressively severe changes of obstructive uropathy, including reduced glomerular number, glomerular hyalinization, cortical cysts and interstitial inflammation. Patient age ranged from 4 days to 19 years (mean 4.8 years). Mean differential function according to histological grade was I–49 percent, II–43 percent, III–42 percent, IV–30 percent and V–25 percent. Of 33 patients with a differential function of 40 percent or greater 26 (79 percent) had a grade I or II biopsy, while 21 percent had a more significant alteration in renal histology. In contrast, when the differential function was less than 40 percent 6 of 18 patients (33 percent) had grade I or II disease on biopsy. In conclusion, in approximately 25 percent of children with ureteropelvic junction obstruction there is a disparity between preoperative differential renal function computed during diuretic renography and renal biopsy.