Renal ectopia and fusion. Embryologic Basis

Outcomes of Robot-Assisted Laparoscopic Isthmus Division Using Endoscopic Transection Equipment in the Treatment of Symptomatic Horseshoe Kidney

Background: The surgical treatment of horseshoe kidney (HSK) remains a huge challenge because of the complex anatomy and abnormal blood vessel distribution. Therefore, this study aimed to evaluate the surgical technique and outcomes of robot-assisted laparoscopic isthmus division using endoscopic transection equipment (endoscopic linear stapler; Ethicon, ECHELON 60 FLEX™) in the treatment of symptomatic HSK and to conduct a literature review. Materials and Methods: Patients with HSK who underwent robot-assisted laparoscopic isthmus division using endoscopic transection equipment from August 2015 to August 2019 at the First Affiliated Hospital of Anhui Medical University in China were recruited. Isthmus division was conducted using an endoscopic linear stapler. Results: All 10 surgeries were performed successfully. Major organs and large blood vessels were effectively protected. Only 1 patient presented with postoperative perinephric effusion. The mean operative time was 179 minutes, and the mean length of the postoperative hospital stay was 6 days. During the 1- to 5-year follow-up, all patients were cured with mitigated symptoms and improved renal function, except for 1 patient with transitional cell carcinoma who died of multiple metastases 18 months postoperatively. Conclusion: Robot-assisted laparoscopic isthmus division using endoscopic transection equipment is a safe and effective method to manage patients with symptomatic HSK and to help them have few complications and quick recovery. Clinical Trial Registration No: Quick-PJ 2021-03-18.

What a difference a delay makes! CT urogram: a pictorial essay

PURPOSE

The aim of this pictorial essay is to demonstrate several cases where the diagnosis would have been difficult or impossible without the excretory phase image of CT urography.

METHODS

A brief discussion of CT urography technique and dose reduction is followed by several cases illustrating the utility of CT urography.

RESULTS

CT urography has become the primary imaging modality for evaluation of hematuria, as well as in the staging and surveillance of urinary tract malignancies. CT urography includes a non-contrast phase and contrast-enhanced nephrographic and excretory (delayed) phases. While the three phases add to the diagnostic ability of CT urography, it also adds potential patient radiation dose. Several techniques including automatic exposure control, iterative reconstruction algorithms, higher noise tolerance, and split-bolus have been successfully used to mitigate dose. The excretory phase is timed such that the excreted contrast opacifies the urinary collecting system and allows for greater detection of filling defects or other abnormalities. Sixteen cases illustrating the utility of excretory phase imaging are reviewed.

CONCLUSIONS

Excretory phase imaging of CT urography can be an essential tool for detecting and appropriately characterizing urinary tract malignancies, renal papillary and medullary abnormalities, CT radiolucent stones, congenital abnormalities, certain chronic inflammatory conditions, and perinephric collections.

Deployment of a Resuscitative Endovascular Balloon Occlusion of the Aorta Device in a Case of Gunshot Wound Injury to a Horseshoe Kidney

A horseshoe kidney (HSK) is a urological malformation that is typically found incidentally after a traumatic injury due to its asymptomatic nature. We present a 25-year-old male with multiorgan injuries secondary to blunt abdominal trauma caused by a gunshot wound. We report the courses of action taken that led to the identification of the HSK and other associated intra-abdominal injuries and the subsequent surgical management. Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an improving minimally invasive technique that was used to control hemorrhage in the early preoperative stages and during surgical repair of the injuries. Multiorgan injuries that involve an HSK are uncommon. Our interest in the case relies on the rarity and unique aspects of the injuries and the recovery of the patient following the use of REBOA.

Crossed Fused Ectopia of Kidney – An Account of Tertiary Healthcare Center Experience

Background:

Crossed renal ectopia with fusion is the abnormal migration of the kidney to the opposite side of the insertion of the ureter to the bladder. It is the second most common congenital anomaly of the kidney and urinary tract preceded by horseshoe kidney. The following article serves to highlight the anomaly in a conglomeration of 17 unique cases, managed in our tertiary care centre over a period of 5 years.

Materials and Methods:

This is a descriptive study analysing the demographic features and the management of seventeen patients diagnosed with crossed renal ectopia with fusion during the period January 2012 to January 2017. Radiological modalities of investigation were modified as per the anomaly. The management plan was devised keeping in mind, the essence of preserving the functional unit.

Results:

Of the seventeen cases, nine patients were symptomatic and eight were asymptomatic. The most recurring crossed renal ectopia with fusion was L- shaped (n=6), disc shaped (n=6) sigmoid shaped (n=2), inferior (n=1), cake shaped (n=1) and superior ectopia (n=1). Left to right ectopia (n=9) was more common than right to left (n=8). Three patients had a solitary crossed ectopia. Out of nine symptomatic patients, six patients underwent surgical procedures, the remaining three were treated conservatively and advised regular biannual follow-up with imaging.

Conclusion:

The management of crossed renal ectopia with fusion is individualised according to the underlying urological anomaly and its sequelae. Importance is given to preserve the renal function whenever possible. Reconstructive surgeries like pyeloplasty, ureteric reimplantation, boari flap can salvage some function in these units.

Role of magnetic resonance urography in pediatric renal fusion anomalies

Renal fusion is on a spectrum of congenital abnormalities that occur due to disruption of the migration process of the embryonic kidneys from the pelvis to the retroperitoneal renal fossae. Clinically, renal fusion anomalies are often found incidentally and associated with increased risk for complications, such as urinary tract obstruction, infection and urolithiasis. These anomalies are most commonly imaged using ultrasound for anatomical definition and less frequently using renal scintigraphy to quantify differential renal function and assess urinary tract drainage. Functional magnetic resonance urography (fMRU) is an advanced imaging technique that combines the excellent soft-tissue contrast of conventional magnetic resonance (MR) images with the quantitative assessment based on contrast medium uptake and excretion kinetics to provide information on renal function and drainage. fMRU has been shown to be clinically useful in evaluating a number of urological conditions. A highly sensitive and radiation-free imaging modality, fMRU can provide detailed morphological and functional information that can facilitate conservative and/or surgical management of children with renal fusion anomalies. This paper reviews the embryological basis of the different types of renal fusion anomalies, their imaging appearances at fMRU, complications associated with fusion anomalies, and the important role of fMRU in diagnosing and managing children with these anomalies.

The horseshoe kidney: Surgical anatomy and embryology

Horseshoe kidneys are a common, yet enigmatic, renal malformation. This review critically appraised the literature surrounding the embryology, etiology and clinical anatomy of horseshoe kidneys. The systematic literature search produced 104 articles, and 56 primary and further secondary references. There were several etiological theories regarding horseshoe kidneys. The established view was that during ascent, the kidneys come into close apposition as they pass through an arterial fork. Another possible mechanism related to lateral flexion of the trunk or rotation of the caudal embryo; the association of asymmetrical horseshoe kidneys with a number of vertebral conditions supported this hypothesis. More recent animal models implicated the notochord and sonic hedgehog signaling. Furthermore, it has been suggested that the isthmus may be the result of ectopic mesenchymal tissue. Surgical anatomy of the horseshoe kidney is complex, due to variability in location, orientation and blood supply. Both arterial and venous anatomy is highly variable. This raised the question of whether anomalous blood supply is the cause or result of abnormal renal position. In the majority of cases, the isthmus contained functional renal parenchyma. In over 90% of cases, fusion between the kidneys occurred at the lower pole. Despite commonly being quoted as 'held back by the inferior mesenteric artery' at L3, in reality the isthmus was only found immediately inferior to this in 40% of cases.

Ureteral Involvement Within an Incarcerated Inguinal Hernia in a Patient With Crossed-fused Renal Ectopia

Crossed-fused renal ectopy is an uncommon abnormality of the genitourinary tract that results from errors during embryological development. Ureteral herniation represents another rare anatomic event and can often occur from spontaneous, postoperative, and congenital causes (Allam, Johnson, Grewal & Johnson 2015; Pollack, Popky & Blumberg 1975). Here, we discuss the complex clinical course of a patient with crossed-fused renal ectopia who presents with symptoms due to ureteroinguinal herniation and provide a brief overview of the literature. We highlight the clinical considerations in the management of this patient and provide a potential anatomical and embryological explanation for his presentation.

Customized fenestrated endovascular graft repair of abdominal aortic aneurysm with concomitant horseshoe kidney

The occurrence of an abdominal aortic aneurysm (AAA) with horseshoe kidney (HSK) is an uncommon but complex surgical problem. This report outlines three such cases, the particular issues encountered and how customized endovascular grafts were successfully used to overcome them. Case one shows an accessory renal artery arising from the left common iliac artery, case two shows a right accessory renal artery from the AAA sac and case three has the right renal artery coming off the distal abdominal aorta within the sac. Across three patients, each graft had a single custom fenestration, which preserved a total of three major vessels with no change in renal function. Customized endografts are a viable tool to preserve aberrant vessels and thus renal mass in AAA and HSK. Customized endografts require an extensive work-up and are currently expensive to fabricate. However they are rapidly evolving as a mainstream tool in vascular surgery and provide a solution in cases of aberrant visceral vasculature.

Pancake Kidney Detected on Renal Scintigraphy

Pancake kidney is an extremely rare renal anomaly resulting from abnormal renal ascent and subsequent fusion. The authors describe a patient with pancake kidneys detected on a Tc-99m DTPA scan. The case reported depicts the scintigraphic findings in such a patient having a pancake kidney.

[Renal cell carcinoma in crossed fused renal ectopia]

Crossed renal ectopia its a rare congenital malformation and in most cases it presents with fusion of both kidneys. Patients should be asynptomatic until 4a-5a decade and at that time they unfold urinary infection, urolithiasis, abdominal mass or pain that simulates a gastric disease. We report a case of renal cell carcinoma in a patient with crossed fused renal ectopia, showed in a Scan that was performed for gastric disease suspicion.

The incidence of associated urological abnormalities in children with renal ectopia

PURPOSE

We evaluate the incidence of associated urological abnormalities in children with renal ectopia (RE).

MATERIALS AND METHODS

We retrospectively reviewed database records of 99 consecutive pediatric cases of RE diagnosed at our hospital between 1988 and 2001.

RESULTS

Mean patient age at diagnosis was 13 months (range 0 to 9 years, SD 2.2 years). Twenty children were evaluated for symptoms, while the remainder were asymptomatic and evaluated after prenatal or postnatal ultrasound finding of RE. There were 10 cases of crossed renal ectopia and 89 cases of simple renal ectopia (S-RE), of which 82 were unilateral and 7 bilateral. The most frequent associated urological abnormality was vesicoureteral reflux (VUR), which was present in 20% of patients with crossed renal ectopia and 30% with S-RE. In patients with bilateral S-RE the incidence of VUR increased to 71%. In patients with unilateral S-RE VUR involved the orthotopic kidney in more than 85% of the cases. Moreover, technetium dimercapto-succinic acid scans documented primitive reduction of function of the ectopic kidney in 87% of the unilateral S-RE cases. Other associated urological anomalies were present in 14% of patients, the most frequent of which were contralateral renal dysplasia (4%), cryptorchidism (5%) and hypospadias (5%).

CONCLUSIONS

A high proportion of children with renal ectopia have associated urological anomalies, and VUR is the most common. The presence of VUR in the normally positioned kidney together with decreased function of the ectopic kidney might predispose these children if not recognized and treated to renal function impairment.

High prevalence of ectopic kidney in Coast Province, Kenya

OBJECTIVE

To establish the prevalence of congenital urinary tract abnormalities in a full population-based ultrasound survey of an area of coastal Kenya.

METHODS

Ultrasound examination of 3118 residents of 912 households, including all available subjects over 2 years of age, residing in five contiguous rural villages 50 km south of Mombasa.

RESULTS

Survey findings indicated simple renal ectopia in 11 of 3118 subjects (0.35%) and renal agenesis in three (0.096%). No cases of horseshoe kidney or complex urinary anomaly were detected, and no cases of multiple congenital anomaly were found. Ectopia cases were evenly distributed between men and women, and across the five study villages. None of the individuals affected by renal ectopia were closely related (i.e. <5th-degree relations).

CONCLUSION

There is an unusually high prevalence of ectopia among unrelated subjects in this area. In this setting, the findings suggest either a common exposure to teratogenetic factors, or a hereditary condition with variable penetrance, where more severely affected individuals are not observed because of foetal/infant mortality.

Renal duplication and fusion anomalies

Renal duplications and fusion anomalies in children often present challenging problems. The diagnostic evolution of these entities often consists of upper tract imaging to evaluate function and help diagnose obstruction, and lower tract imaging to assess reflux and at times voiding dynamics. The clinician needs to be aware of the variable presentations of these lesions, their evolution, and the therapeutic interventions that may be required to resolve problems resulting from them.

Somitic-vertebral correlation and vertebral levels in the human embryo

Somitic and vertebral interrelationships and levels were studied in 84 human embryos of stages 9-23 (3-8 postovulatory weeks). The first four somites are occipital, the occipitocervical junction is at somites 4/5, and eight somites are involved in the cervical region: X, Y, Z, and C. 3-7. By stage 17 the total number of occipitovertebral "units," namely 38 or 39, is attained. Resegmentation (Neugliederung) of sclerotomes is not supported. A new scheme of somitic/vertebral correlation is proposed in which somites and centra are in register. Differential growth of the regions of the vertebral column was calculated, and it was found that the percentages of the total column occupied by the various regions vary from one stage to another. The cervical and coccygeal regions decrease, the thoracic and lumbar regions increase, and the sacral region remains more or less constant during embryonic development. The following structures descend with reference to the vertebral column during the embryonic period proper: roots of lower limbs, thyroid gland and thymus, tracheal bifurcation, lungs, heart, diaphragm, abdominal arteries, mesonephroi, and suprarenal glands. The gonads may descend slightly. The scapulae and the separation point between the trachea and the esophagus remain at a fairly constant level. The metanephroi ascend. The migration of many of these structures (e.g., the heart, diaphragm, and metanephroi) is much more marked in the embryonic period than later although it continues during the fetal and postnatal periods. The conus medullaris ascends during the fetal period. Anomalies of migration that affect such organs as the thyroid gland, gonads, and metanephroi are discussed.

Pelvic kidney in infants and children: experience with 16 cases

Sixteen cases of pelvic kidney were treated in the past 12 yr. Some are associated with other major malformations including ureteropelvic junction obstruction, vesicoureteral reflux, ectopic ureter, vaginal atresia, and vertebral anomalies. The pivotal role of the resorbing mesonephros and its duct in Mullerian duct development and in renal development and ascent are considered.

The timing and sequence of events in the development of the human vertebral column during the embryonic period proper

A documented scheme of the early development of the human vertebrae is presented. It is based on (1) reports of workers who personally studied staged human embryos, and (2) personal observations and confirmations. The necessity of studying staged embryos in order to determine the precise sequence of developmental events is stressed.

Crossed renal ectopia

Crossed renal ectopia is an unusual congenital anomaly, probably produced by abnormal development of the ureteral bud. The deformity itself produces no symptoms and the clinical presentation generally is for obstruction and infection. In our series the adult patients presented most commonly with urinary tract infections, while the pediatric patients presented most often with multiple congenital anomalies, especially of the skeletal system.

Horseshoe kidney with multicystic dysplasia associated with ureterocele

This is a case report of a horseshoe kidney one side of which contains a multicystic dysplastic element associated with a ureterocele. The surgical management and embryologic basis are reviewed.