Helical computed tomography for identification of crossing vessels in ureteropelvic junction obstruction-comparison with operative findings

Ureteropelvic Junction Obstruction Caused by Crossing Vessels in Infants and Young Children

BACKGROUND

To analyze the clinical characteristics of ureteropelvic junction obstruction (UPJO) caused by crossing vessels (CV) in infants and young children.

METHODS

A retrospective analysis was performed on children with UPJO who underwent primary surgery. Patients were classified into laparoscopic pyeloplasty (LP) and open pyeloplasty (OP) groups and classified as ≤3 or >3 (years old) groups. Children with CV-caused UPJO were identified.

RESULTS

A total of 747 patients were included. Ninety cases of CV were identified. The CV discovery rate was higher in the LP group (78/457, 17.1%) than in the OP group (12/290, 4.1%) (P < 0.001). In the ≤3 group, the CV discovery rate in the LP group (27/144, 18.8%) was higher than that in the OP group (11/274, 4.0%) (P < 0.001). In the LP group, there was no significant difference between ≤3 (27/144, 18.8%) and >3 (51/313, 16.3%) groups in the CV discovery rate. The rate in children with UPJO was not significantly different at any age (P > 0.05). Progressive aggravation of hydronephrosis (21/27, 77.8%) and symptomatic hydronephrosis (44/51, 86.3%) were the main surgical indications in the ≤3 and > 3 groups, respectively. There were no preoperatively confirmed cases of CV in the ≤3 group. In the OP group, five patients underwent reoperation, three of whom were due to failure to detect CV during the initial operation.

CONCLUSIONS

The CV distribution is similar in children with UPJO across all ages; CV in infants and young children are not rare. LP should be considered as CV are prone to being missed during OP.

LEVELS OF EVIDENCE

III.

Initial experiences with preoperative three-dimensional image reconstruction technology in laparoscopic pyeloplasty for ureteropelvic junction obstruction

Background

To explore the clinical value of three-dimensional image reconstruction technology (3DIT) on preoperative surgical planning and perioperative outcomes in laparoscopic pyeloplasty (LP).

Methods

Data of 25 patients with ureteropelvic junction obstruction (UPJO) admitted to our hospital from January 2018 to January 2019 was analyzed retrospectively. All patients underwent preoperative enhanced computed tomography (CT) scanning. In the 12 cases in the 3DIT group, preoperative planning involved the use of virtual operation and morphometry based on reconstruction of the CT data into three-dimensional (3D) images. Surgery in the other 13 cases was performed with traditional CT examination. Demographic, surgical outcome, and postoperative parameters were compared between these two groups.

Results

Reconstructed 3D images clearly showed the spatial structural relationships between the UPJO and surrounding blood vessels. In all 25 cases surgery was completed with no conversion to open surgery. Preoperative 3DIT analyses resulted in significant improvements to mean operation time (107.76 vs. 141.58 min, P=0.024), mean time of dissociating ureteropelvic junction (UPJ) (11.26 vs. 19.40 min, P=0.020), and mean estimated blood loss volume (23.84 vs. 49.16 mL, P=0.028). There were no statistically significant differences in perioperative complications, postoperative hospital stays or postoperative drainage time.

Conclusions

3DIT based on enhanced CT scans is of clinical value in the treatment of UPJO, as it can provide accurate anatomical information and reliable guidance for preoperative operation planning, and it facilitates image-guided LP.

The role of multidetector CT angiography in characterizing vascular compression syndromes of the abdomen

Background

Various abdominal vessels can compress the adjacent structures or in turn can get compressed by them. Most of these compression syndromes present with non-specific symptoms. Unlike the common causes of acute abdomen, the various vascular compression syndromes have bizarre clinical presentations and subtle imaging findings, which can easily be missed by the physicians as well as the radiologists.

Main body of the abstract

This is a retrospective study which was done for a period of 3 years from April 2015 to April 2018 using a 64-slice CT scanner. Among 2412 cases that came for evaluation, 114 patients were diagnosed to have one of the various vascular compression syndromes. These 114 cases were further managed either conservatively or surgically depending on the pathology and the severity of the compression. The syndromes discussed in this article include median arcuate ligament syndrome (29 cases), superior mesenteric artery syndrome (23 cases), portal biliopathy (3 cases), nutcracker syndrome (6 cases), pelvi-ureteric junction obstruction due to crossing of vessels (8 cases), and retrocaval ureter and May-Thurner syndrome (45 cases).

Conclusions

The primary goal of this article is to reinforce the knowledge of the radiologists of the various vascular compression syndromes and to make them possess a high degree of vigilance to detect them. This article elaborates the imaging findings of these syndromes and the role of multidetector CT angiography in diagnosing them.

MDCT and MR Urogram Spectrum of Congenital Anomalies of the Kidney and Urinary Tract Diagnosed in Adulthood

OBJECTIVE

Congenital anomalies of the kidneys and urinary tract (CAKUT) encompass a spectrum of anomalies that result from genetic, epigenetic, environmental, and molecular signal aberrations at key stages of urinary tract development. CAKUT can be seen incidentally on cross-sectional imaging of the abdomen or can be a cause for adult-onset chronic kidney disease, posing new challenges for nephrologists, urologists, and radiologists.

CONCLUSION

Awareness of CAKUT and familiarity with their imaging findings permit optimal patient management and thorough workup to prevent hypertension and progression from CAKUT to renal failure. The purpose of this article is to review the cross-sectional imaging findings of CAKUT that may present in adulthood.

Long-term results with the laparoscopic transposition of renal lower pole crossing vessels

BACKGROUND

For the treatment of ureterovascular pelviureteric junction obstruction (PUJO), transposition of lower pole crossing vessels (LPCV) has been described as an alternative to dismembered pyeloplasty.

PURPOSE

To report on the long-term follow-up of children after laparoscopic transposition of LPCV.

METHODS

A retrospective analysis of 70 children consecutively treated by laparoscopic transposition of LPCV. Candidate patients were selected on the basis of clinical history, renal ultrasound (US), and pre-operative mercaptoacetyltriglycine (MAG-3) scan. Selection criteria included: presence of LPCV with SFU Grade 1-2 hydronephrosis, impaired drainage on MAG-3 and intraoperative normal pelviureteric junction (PUJ) and ureter peristalsis. Thinned parenchyma, impaired renal function, or history of prenatal hydronephrosis were not considered as exclusion criteria. Children were clinically followed up with US and MAG-3 scan. Success was defined by symptom resolution with improvement in hydronephrosis.

RESULTS

Seventy children, aged 8.3 years (range 2.75-16.0), were selected. Procedures were performed through transperitoneal laparoscopy (n = 42) or were robotic-assisted (n = 28). Operative time was 120 min and length of hospital stay was 2 days. The outcome was successful in 67/70 patients (96%), with a median follow-up of 52 months (range 13-114). There were three failures in children who eventually underwent dismembered pyeloplasty for a symptomatic, undiagnosed, intrinsic PUJ obstruction. Two of them had been postnatally followed for a resolving prenatally diagnosed hydronephrosis. Three children became free of symptoms, had improved hydronephrosis, but still showed impaired drainage on MAG-3 and are being closely followed up.

DISCUSSION

Although this procedure proves to have long-term efficiency in selected indications, the main challenge is to intraoperatively ascertain the absence of associated intrinsic stenosis. Objective criteria remain difficult to establish, but intraoperative findings, including dependent, funnel-shaped, normal-looking PUJ with decreasing hydronephrosis after pelvis and LPCV mobilisation, and efficient peristalsis across the PUJ under intraoperative diuretic test, represent a low likelihood of associated intrinsic stenosis. Ipsilateral impaired renal function doesn't seem to be associated with an adverse outcome. In contrast, a prenatal history of mild or self-resolving hydronephrosis in a patient later presenting with intermittent dilatation, raises the suspicion of associated intrinsic PUJ obstruction, as it is associated with a higher risk of failure.

CONCLUSION

With a long postoperative follow-up, the robotic-assisted or laparoscopic vascular hitch procedure has been successful in treating a selected group of children with obstructive LPCV, and represents a safe and reliable alternative to standard dismembered pyeloplasty in the absence of intrinsic PUJO suspected on prenatal US.

Hydronephrosis: Comparison of extrinsic vessel versus intrinsic ureteropelvic junction obstruction groups and a plea against the vascular hitch procedure

INTRODUCTION

Pediatric ureteropelvic junction obstruction (UPJO) due to an extrinsic crossing vessel (CV) is rare and often remains undiagnosed preoperatively. Vascular hitch procedures are often performed as associated intrinsic obstruction is not expected. We compared data and intravenous urography (IVU) findings of patients with aberrant CV versus those with intrinsic UPJO, all undergoing open dismembered pyeloplasty.

PRIMARY OBJECTIVE

Is accurate pre-operative diagnosis of aberrant CV causing extrinsic UPJO possible?

SECONDARY OBJECTIVE

To assess differences in the demographic, clinical, radiological, intra-operative features and postoperative improvement after pyeloplasty between patients with a CV and those with only intrinsic UPJO.

PATIENTS AND METHODS

Prospective study of all children below 12 years with UPJO presenting to a tertiary referral centre and who underwent open Anderson - Hynes dismembered pyeloplasty between 2003 and 2013 was conducted. Pre-operative investigations included serial ultrasonography, renal dynamic [ethylene di-cysteine (EC)] scan and IVU. These were repeated 3 months after pyeloplasty. Pre-operative IVUs of children with CV were compared with the IVUs of an equal number of similar aged children, randomly selected from the intrinsic obstruction group.

RESULTS

Pyeloplasty was performed in 643 children during the study period. Data of 33 children with aberrant CVs (mean age 6.99 years) were compared with the remaining 610 children (mean age 3.27 years) with only intrinsic obstruction. Highly significant associations of those with CV included age above 2 years, female gender, associated anomalies, abdominal pain in those above 2 years and poor preoperative function on IVU. Specific IVU features which were statistically highly significant in favor of presence of CV were small, intrarenal and globular flat bottomed pelvis. (Figure) Calyceal dilatation was also more prominent in the CV group. A funnel shaped, extrarenal pelvis was highly significant in favor of intrinsic obstruction. There was associated intrinsic obstruction in addition to CV obstruction in 8 children. All children symptomatically improved after pyeloplasty and did well on long term follow up. The majority showed improvement or stabilization of function on EC scan.

DISCUSSION

With the advent of antenatal ultrasonography, most children with UPJO are detected early. Children with CV tend to present later. This is often detected during surgery. Color Doppler is useful but is operator dependant and not performed routinely. In this study, IVU showed the presence of obstruction and loss of function unlike color Doppler, but also revealed specific diagnostic features not previously reported in literature. This can help in accurate preoperative prediction and avoid endopyelotomy, or a dorsal lumbotomy/retroperitoneal approach. Renal function in CVs is expected to be good as the obstruction is thought to be intermittent. However, we noted delayed contrast uptake on IVU in 60.6% and differential renal function on EC scan below 40% in 17 patients (56.6%). These indicate the effect of the obstruction on the renal parenchyma and the importance of early detection. Higher association with other anomalies and higher incidence in females has also not been emphasized in the literature so far. We noted associated intrinsic obstruction in 24.24% patients which is highly significant. This category of patients is likely to be missed and inappropriately treated if a "vascular hitch procedure" is performed. None of our patients had postoperative complications.

CONCLUSIONS

Characteristic features were seen on IVU helping in preoperative diagnosis which can be extrapolated to magnetic resonance urography. There is a higher association of CV in age above 2 years, females, associated congenital anomalies, delayed uptake on IVU and differential renal function below 40% compared to intrinsic obstruction. Associated intrinsic obstruction in 24% with no postoperative complications indicates the superiority of dismembered pyeloplasty over vasculopexy procedures.

Multidetector CT of vascular compression syndromes in the abdomen and pelvis

Certain abdominopelvic vascular structures may be compressed by adjacent anatomic structures or may cause compression of adjacent hollow viscera. Such compressions may be asymptomatic; when symptomatic, however, they can lead to a variety of uncommon syndromes in the abdomen and pelvis, including median arcuate ligament syndrome, May-Thurner syndrome, nutcracker syndrome, superior mesenteric artery syndrome, ureteropelvic junction obstruction, ovarian vein syndrome, and other forms of ureteral compression. These syndromes, the pathogenesis of some of which remains controversial, can result in nonspecific symptoms of epigastric or flank pain, weight loss, nausea and vomiting, hematuria, or urinary tract infection. Direct venography or duplex ultrasonography can provide hemodynamic information in cases of vascular compression. However, multidetector computed tomography is particularly useful in that it allows a comprehensive single-study evaluation of the anatomy and resultant morphologic changes. Anatomic findings that can predispose to these syndromes may be encountered in patients who are undergoing imaging for unrelated reasons. However, the diagnosis of these syndromes should not be made on the basis of imaging findings alone. Severely symptomatic patients require treatment, which is generally surgical, although endovascular techniques are increasingly being used to treat venous compressions.

Nature of crossing vessels in patients with radiographically normal ureteropelvic junctions: prevalence and anatomic characteristics

OBJECTIVE

To evaluate the prevalence and characteristics of crossing vessels in asymptomatic patients with a radiographically normal ureteropelvic junction.

MATERIALS AND METHODS

We retrospectively reviewed the computed tomography angiography images of 601 patients who were evaluated for possible living organ donation at the University of Minnesota from 2005 to 2008. One patient had asymptomatic hydronephrosis and was excluded from the analysis. The prevalence and characteristics of crossing vessels at the ureteropelvic junction were determined, including vessel location, origin, size, distance from the ureteropelvic junction, and vessel type (artery or vein).

RESULTS

The prevalence of crossing vessels at the radiographically normal ureteropelvic junction was 22.7%. A total of 163 crossing vessels were present in 136 patients; 60.1% were left-sided and 39.9% were right-sided. Arteries accounted for 81.0% of the crossing vessels and veins for 19.0%. Accessory lower pole renal vessels originating from the great vessels constituted 59.5% of the crossing vessels. The location of the crossing vessel relative to the ureteropelvic junction varied and included anterior (25.8%), anterolateral (36.8%), medial (14.6%), anteromedial (2.5%), lateral (12.9%), and posterior (7.4%). The mean diameter and mean distance of the crossing vessel from the ureteropelvic junction was 3.3 mm and 1.8 mm, respectively.

CONCLUSION

The prevalence of crossing vessels in asymptomatic, healthy patients with a radiographically normal ureteropelvic junction was 22.7%, lower than that seen in association with ureteropelvic junction obstruction. The location of the crossing vessels varied about the ureteropelvic junction, and no location was consistently free of traversing vessels.

Endopyelotomy for pediatric ureteropelvic junction obstruction: a review of our 25-year experience

PURPOSE

We elucidate the role of endopyelotomy as a primary and secondary intervention for ureteropelvic junction obstruction in children.

MATERIALS AND METHODS

We retrospectively identified 79 pediatric patients who underwent endopyelotomy for ureteropelvic junction obstruction between 1986 and 2011. Eleven patients were lost to followup and were excluded from analysis. Patient demographics, operative information, complications and success rates were reviewed for the remaining 68 patients. Treatment success was defined as the absence of symptom recurrence and improved radiographic features on ultrasound, computerized tomography, diuretic renogram or excretory urogram at most recent followup.

RESULTS

Primary endopyelotomy data were analyzed in 37 patients with a median age of 11.1 years. The success rate was 65% at a median followup of 34 months (range 1.5 to 242). Treatment failure occurred in 13 patients with a median time to failure of 8 months (range 1.5 to 131). There were 8 cases of failure during 12 months of surgery. Secondary endopyelotomy data were analyzed in 31 patients with a median age of 6.5 years. The success rate was 94% at a median followup of 61 months (range 1 to 204). Treatment failure occurred in 2 patients at 1 and 6 months. Approximately two-thirds of all procedures used an antegrade approach.

CONCLUSIONS

Primary endopyelotomy is significantly less successful than pyeloplasty in the treatment of ureteropelvic junction obstruction in pediatric patients. However, secondary endopyelotomy following failed pyeloplasty represents a viable alternative to redo pyeloplasty.

CT angiography of the renal circulation

Although catheter angiography remains the accepted gold standard for imaging of the renal vascular system, rapid progress in cross-sectional imaging techniques has caused a paradigm shift in many diagnostic algorithms toward noninvasive techniques such as computed tomographic angiography (CTA). CTA's cross-sectional imaging techniques provide an opportunity for comprehensive renal investigation that would be impossible with angiography alone. While other competing noninvasive technologies such as ultrasound and magnetic resonance angiography can be used successfully in renal imaging, the benefits of CTA are substantial, including high spatial and temporal resolution, widespread availability, implantable device compatibility, and easy technical reproducibility. This article describes the technical considerations relevant to CTA of the renal vascular system, postprocessing algorithms for volumetric data, and numerous specific applications.

Accessory or additional renal arteries show no relevant effects on the width of the upper urinary tract: a 64-slice multidetector CT study in 1072 patients with 2132 kidneys

OBJECTIVE

The aim of this study was to find out on an unselected patient group whether crossing vessels have an influence on the width of the renal pelvis and what independent predictors of these target variables exist.

METHODS

In this cross-sectional study, 1072 patients with arterially contrasted CT scans were included. The 2132 kidneys were supplied by 2736 arteries.

RESULTS

On the right side, there were 293 additional and accessory arteries in 286 patients, and on the left side there were 304 in 271 patients. 154 renal pelves were more than 15 mm wide. The greatest independent factor for hydronephrosis on one side was hydronephrosis on the contralateral side (p<0.0001 each). Independent predictors for the width of the renal pelvis on the right side were the width of the renal pelvis on the left, female gender, increasing age and height; for the left side, predictors were the width of the renal pelvis on the right, concrements, parapelvic cysts and great rotation of the upper pole of the kidney to dorsal. Crossing vessels had no influence on the development of hydronephrosis. Only anterior crossing vessels on the right side are associated with widening of the renal pelvis by 1 mm, without making it possible to identify the vessel as an independent factor in multivariate regression models.

CONCLUSION

The width of the renal pelvis on the contralateral side is the strongest independent predictor for hydronephrosis and the width of the renal pelvis. There is no link between crossing vessels and the width of the renal pelvis.

[Multislice CT arteriography in the pre-surgical evaluation of patients with ureteropelvic junction stenosis]

INTRODUCTION

The current treatment of choice for ureteropelvic stenosis is endopyelotomy, but the presence of vessels in contact with the stenotic area of the ureteropelvic junction reduces the success of these interventions and increases vascular and hemorrhagic complications. The aim of our study was to use multislice CT arteriography to evaluate patients prior to surgery for ureteropelvic junction stenosis.

PATIENTS AND METHODS

16 patients with ureteropelvic junction stenosis underwent multislice CT arteriography; multidirectional images and three-dimensional reconstructions were used to identify and characterize vessels in contact with the stenotic area of the ureteropelvic junction.

RESULTS

A total of eight vessels (four arteries and four veins) in six (38%) patients were found in contact with or passing within 2 mm of the ureteropelvic junction. The vessels were located anterior to the junction in four cases; it was posterior in one case, and anteromedial in the other. Endopyelotomy was contraindicated in the six patients in whom vessels were found in contact with the ureteropelvic junction. The presence of the vessels was confirmed during surgery in five of these patients; the remaining patient did not undergo surgery).

CONCLUSION

Multislice CT arteriography allows adequate presurgical evaluation of ureteropelvic junction stenosis, detecting the presence of crossing vessels and facilitating the planning of the surgical approach in these patients.

Contrast-enhanced magnetic resonance angiography for the detection of crossing renal vessels in children with symptomatic ureteropelvic junction obstruction: comparison with operative findings

BACKGROUND

Crossing renal vessels (CRV) are associated with ureteropelvic junction (UPJ) obstruction, particularly when presentation is beyond the neonatal period. Their presence may influence surgical management.

OBJECTIVE

To evaluate the accuracy of contrast-enhanced magnetic resonance angiography (CE-MRA) in the identification of CRV in children requiring surgical treatment of symptomatic UPJ obstruction, against a gold standard of laparoscopic or open surgical findings.

MATERIALS AND METHODS

We reviewed CE-MRA studies (3-D T2-weighted turbo spin-echo and multiphase 3-D spoiled gradient echo following intravenous gadolinium administration) of 14 children, age range 6-15 years, performed prior to surgery for suspected CRV-related UPJ obstruction. Consensus reviews of the CE-MRA studies were compared with surgical findings.

RESULTS

CE-MRA demonstrated CRV at the level of the obstruction in nine and no crossing vessels in five children. These were all verified intraoperatively (chi2=14.0; P<0.001). In eight of the nine patients with CRV there was no evidence of intrinsic obstruction at surgery. In the remaining patient there was fibrosis of the upper ureter.

CONCLUSION

CE-MRA is an accurate means of identifying CRV in children older than 6 years with symptomatic UPJ obstruction.

Multidetector computed tomography arteriography in the preoperative assessment of patients with ureteropelvic junction obstruction

BACKGROUND

Nowadays, endoscopic management of ureteropelvic junction (UPJ) obstruction is the treatment of choice. However, in the presence of crossing vessels, the success rate of endoscopic management decreases and the risk of hemorrhagic and vascular complications rises. The purpose of this study is to evaluate patients with UPJ obstruction using contrast enhanced multidetector computed tomography (CT) angiography to aid in surgical planning and management.

PATIENTS AND METHODS

Between 2001 and 2005, 27 patients (mean age: 43 years; age range: 17-75 years) with UPJ obstruction were studied with multidetector CT angiography. Identification and characterization of crossing vessels was performed with multidirectional images and three-directional reconstructions.

RESULTS

12 patients (44%) were found to have 16 crossing vessels (vessels in contact with the UPJ or within a vicinity of less than 2 mm). Nine of these vessels were arteries and seven were veins. Nine vessels crossed anteriorly, two posteriorly, and one anteromedially. Endopyelotomy was contraindicated in these 12 patients due to the presence of crossing vessels. Eleven out of the 12 patients underwent a pyeloplasty by open surgery or laparoscopy, where the presence of crossing vessels was confirmed. One of the 12 patients did not undergo surgery.

CONCLUSION

Multidetector CT angiography permits an adequate preoperative assessment of patients with UPJ obstruction as it is able to identify the presence and location of crossing vessels. Furthermore, it allows to study in detail the anatomy of the renal area and its vascular variants.

Laparoscopic transposition of lower pole vessels--the 'vascular hitch': an alternative to dismembered pyeloplasty for pelvi-ureteric junction obstruction in children

OBJECTIVE

Dismembered pyeloplasty is the traditional technique in the management of ureterovascular pelvi-ureteric junction obstruction (PUJO) in children. Controversy remains regarding the role of lower pole vessels as the sole aetiology for PUJO. Endopyelotomy and concomitant laparoscopic transposition of lower pole vessels for PUJO has been described in adults. We describe our technique of laparoscopic transposition of lower pole vessels in children with PUJO, leaving the PUJ intact.

PATIENTS AND METHODS

Thirteen patients (seven boys and six girls) with a mean age of 10.2 years (range 7-16 years) underwent laparoscopic transposition of lower pole vessels. Surgery was indicated on the basis of intermittent pain and ultrasound/MAG3 appearance of obstruction with or without reduced function. The technique involved laparoscopic transperitoneal mobilization of the lower pole vessels from the region of the PUJ thereby freeing the junction and transposing them superiorly onto the anterior wall of the pelvis. The main outcome measures were relief of pain and improvement in ultrasound appearance or drainage parameters on a postoperative MAG3 renogram performed within 4-6 weeks of surgery.

RESULTS

Median operating time was 92 min. All patients were discharged within 36 h of surgery. All patients remain pain free at a median of 6 months (range 3-18 months). Twelve patients showed good drainage on the postoperative MAG3 renogram and improvement in ultrasound appearance. One patient had recurrent symptoms requiring insertion of a JJ stent. She has undergone further laparoscopic exploration. The vessels were in their transposed position and there was a kink at the PUJ which was released. She had a vertical pyelotomy and transverse closure over the JJ stent with good results.

CONCLUSION

This technique is simple and requires less operating time. No anastomosis or temporary JJ stent is required. Our early results are very encouraging with no serious complications.

The absent kidney in99Tcm-MAG3 renogram: a dramatic reversible consequence of contrast nephrotoxicity superimposed on renal obstruction

99Tcm-mercaptoacetyltriglycine (MAG3) renogram is a robust imaging technique used to delineate upper urinary tract obstruction. The changes observed on the renogram are often reversible on relief of obstruction. We present two cases illustrating the extreme consequence of contrast nephrotoxicity on pre-existing obstructed kidneys. In one case, this led to severe impairment of perfusion and uptake observed on 99Tcm-MAG3 renogram and in the second case virtual non-visualization of the obstructed kidney. Subsequent treatment of obstruction, led to dramatic improvement in renal function. It is important for clinicians, nuclear medicine physicians and radiologists to be aware of the potential of contrast nephrotoxicity in obstructed kidneys.

Adult Ureteropelvic Junction Obstruction: Insights with Three-dimensional Multi–Detector Row CT

Ureteropelvic junction obstruction (UPJO) is a benign, congenital condition that remains an enigma in terms of both diagnosis and therapy. On the basis of a series of cases that were referred to the authors in their clinical practice, they found that the unprecedented quality and novel perspectives of multi-detector row computed tomography (CT) with two- and three-dimensional postprocessing allow a comprehensive, single-study assessment of the ureterovascular relationships in UPJO. This topic is important because the causative role of crossing vessels may be questioned on the basis of such studies, and the therapeutic approach may be altered by using precise anatomic images customized to the pathologic features of the individual patient. Although CT images can provide only circumstantial or supportive evidence of the pathophysiology of UPJO, they greatly facilitate therapeutic intervention when it is clinically indicated and may eliminate the need for it in select cases. Careful attention to the postprocessing of CT images may show that the crossing vasculature has no direct relationship to the transition point of the UPJO in many cases.

Detection of crossing vessels as the cause of ureteropelvic junction obstruction: the role of antegrade pyelography prior to endopyelotomy

PURPOSE

To review the utility of antegrade pyelography in detecting crossing vessels as the cause of uretero-pelvic junction (UPJ) obstruction prior to planned endopyelotomy.

MATERIALS AND METHODS

A retrospective review of the medical records, surgical reports, and medical images was performed in 109 consecutive adult patients in our practice who underwent antegrade pyelography just prior to planned endopyelotomy for symptomatic UPJ obstruction between January 1996 and December 2002.

RESULTS

Fourteen patients were identified in whom a specific antegrade pyelographic appearance was detected in the diagnosis UPJ obstruction caused by crossing vessels. Surgical plans were changed in all 14 patients from antegrade endopyelotomy to open surgical pyeloplasty, during which the anterior (ventral) crossing vessels causing obstruction were confirmed. An additional three patients in the reviewed endopyelotomy group clinically failed their initial endopyelotomy procedure and were shown at the time of subsequent open or laparoscopic reconstructive surgery to have UPJ obstruction caused by anterior crossing vessels, but that diagnosis was missed at the time of the initial antegrade pyelogram.

CONCLUSION

A specific antegrade pyelographic appearance was identified to diagnose UPJ obstruction caused by anterior crossing vessels with a sensitivity of 82.4% and a specificity of 100%. The direct obstructing effect of the vessels on the ureter is defined with pyelography as an acute posteriorly angulated ureteral deformity just below a patent UPJ. Recognition of this specific antegrade pyelographic appearance permits use of an appropriate surgical technique for UPJ obstruction repair.

Role of multiphasic helical computed tomography in planning surgical treatment for pelvi-ureteric junction obstruction

OBJECTIVE

To evaluate the role of multiphasic helical computed tomography (CT) in planning surgical treatment for pelvi-ureteric junction obstruction (PUJO).

PATIENTS AND METHODS

Multiphasic helical CT was used in 60 consecutive patients (mean age 32 years, sd 13.72) with primary PUJO. The different images were interpreted before surgery by a urologist and radiologist. The number, type and relation of the crossing vessels to the PUJ were detected. Pyeloplasty (open or laparoscopic) was used in patients where there was a significant crossing vessel (i.e. > 2 mm in diameter and passing at the PUJ) or with ballooning of the renal pelvis. Endopyelotomy (antegrade or retrograde) was used in the other patients. Subjective and objective success rates were determined 3-6 months after treatment and then every 6 months.

RESULTS

Hyperdense renal stones were detected in precontrast images in 15 patients, significant crossing vessels in 33 (55%), and anterior malrotation of the renal pelvis in 23 (38%; 19 associated with significant crossing vessels, i.e. ureterovascular hydronephrosis). A large para-pelvic cyst compressing the PUJ and upper ureter was detected in one patient. Pyeloplasty was used in 45 patients, among whom the sensitivity of multiphasic helical CT in detecting crossing vessels was 97%, the specificity 92% and accuracy 96%. Uncomplicated endopyelotomy was used in 14 patients and percutaneous aspiration of the para-pelvic cyst in one.

CONCLUSION

Multiphasic helical CT can accurately delineate the spatial anatomy of the renal and peri-renal area; it may be important in planning surgical treatment for PUJO, especially when endopyelotomy is considered.

Renal imaging: what the urologist wants to know

Preoperative imaging in renal surgery is of utmost importance in contemporary surgical practice. From a diagnostic standpoint, imaging discovers many renal tumors incidentally before they become symptomatic. These tumors often are amenable to partial renal resection or minimally invasive surgical approaches. In general, surgical interventions for renal abnormalities have evolved to a less invasive endourologic or laparoscopic approach. Selection of the appropriate surgical intervention for renal tumors, collecting system tumors, and hydronephrosis depends heavily on the anatomy of the renal pathology. Thus, renal imaging is crucial in clinical decision-making. This article reviews the contribution of imaging to the surgical management of renal tumors, upper tract urothelial tumors, and ureteropelvic junction obstruction.