The purpose of this study was to evaluate the efficacy and safety of flexible ureteroscopy with holmium laser lithotripsy in the management of calyceal diverticular calculi. In this study, we retrospectively analyzed the clinical data of 27 patients with calyceal diverticular calculi admitted to the Department of Urology of the Zigong First People\'s Hospital from May 2018 to May 2021. Intraoperatively, the diverticular neck was found in all 27 patients, but flexible ureterorenoscopy lithotripsy was not performed in 2 cases because of the slender diverticular neck, and the success rate of the operation was 92.6%. Of the 25 patients with successful lithotripsy, the mean operative time was 76.9 ± 35.5 (43-200) min. There were no serious intraoperative complications such as ureteral perforation, mucosal avulsion, or hemorrhage. Postoperative minor complications (Clavien classification I-II) occurred in 4 (16%) patients. The mean hospital stay was 4.4 ± 1.7 (3-12) days. The stone-free rate was 80% at the 1-month postoperative follow-up. After the second-stage treatment, the stone-free rate was 88%. In 22 cases with complete stone clearance, no stone recurrence was observed at 5.3 ± 2.6 (3-12) months follow-up. This retrospective study demonstrated that flexible ureterorenoscopy with holmium laser is a safe and effective choice for the treatment of calyceal diverticular calculi, because it utilizes the natural lumen of the human body and has the advantages of less trauma, fewer complications, and a higher stone-free rate.

Renal cystic diseases (RCDs) can arise from utero to early adulthood and present with a variety of symptoms including renal, hepatic, and cardiovascular manifestations. It is well known that common RCDs such as autosomal polycystic kidney disease and autosomal recessive kidney disease are linked to genes such as PKD1 and PKHD1, respectively. However, it is important to investigate the genetic pathophysiology of how these gene mutations lead to clinical symptoms and include some of the less-studied RCDs, such as autosomal dominant tubulointerstitial kidney disease, multicystic dysplastic kidney, Zellweger syndrome, calyceal diverticula, and more. We plan to take a thorough look into the genetic involvement and clinical sequalae of a number of RCDs with the goal of helping to guide diagnosis, counseling, and treatment.

The purpose of this study was to investigate the effectiveness and safety of flexible ureteroscopy lithotripsy (FURL) and all-seeing needle-assisted percutaneous nephrolithotomy (PCNL) for the treatment of calyceal diverticula (CD) stones. From June 2012 to November 2020, 24 patients, including 14 females and 10 males, with an average age of 45.6 ± 17.4 years were retrospectively reviewed in this study. Among these patients, 14 were treated with FURL, and 10 underwent all-seeing needle-assisted PCNL. The demographic data, perioperative parameters and complications, as well as follow-up data, were recorded. In the FURL group, the ostium of CD was not identified in two patients, and these patients were finally treated with all-seeing needle-assisted PCNL. The stone clearance rate (SCR) was 64.3%, and the mean blood loss was 0.9 ± 0.8 g/dL. The average operation time was 57.5 ± 17.4 min, and the mean hospital stay was 3.5 ± 1.4 days. A complete resolution of CD was observed in five (41.7%) patients over the average follow-up of 10.8 months. In terms of the all-seeing needle-assisted PCNL, the average operation time was 83.5 ± 32.4 min, and the mean hospital stay was 4.38 ± 2.25 days. The SCR reached 91.7%, and the blood loss was 1.7 ± 1.1 g/dL. Nine patients (75%) were observed to have complete CD resolution over an average of 12.2 months of follow-up. All complications were grade I and II in both the groups. CD stones can be treated minimally invasive and effectively by FURL and PCNL. The effect of FURL greatly depends on the location and anatomy of the diverticula. PCNL is more efficient, and its safety was improved with the help of the all-seeing needle assistance.

To determine the MRU imaging findings of calyceal diverticula in a large cohort of children and to compare the frequency of calyceal diverticula in our cohort with what has been previously reported.
This was a HIPAA-compliant, IRB-approved retrospective study of all patients with suspected CD based on their medical records. All patients in this study underwent MRU at our institution between 2010 and 2017. Two pediatric radiologists reviewed each MRU blinded to clinical information and other urologic imaging regarding the presence, size, location, and morphology of the cyst and presence/absence of contrast within it. The time when contrast first appeared within the cystic mass was recorded, and a χ2 test was used to determine significance on differences between the different characteristics of renal cysts and diverticula.
Fifty children (29 girls and 21 boys; median age of 11.5 years, IQR 7-16) with a total of 66 individual cystic masses were included. 21 (21/66, 31.8%) Cystic masses demonstrated contrast filling and were characterized as diverticula, resulting in a frequency of 26.6 cases per 1000 patients (21/787). The remaining 45 cystic masses (45/66, 68.1%) were cysts. The median diameter of CD was 2.5 cm (IQR 1.5-3.7). Contrast was observed within the cystic mass on average at 4.6 min (SD ± 2.4; range 1.5-13 min). The agreement between both radiologists was 91% (k = 0.78). 6 Cysts and 18 CD were confirmed surgically, MRU demonstrated accurate diagnosis in 100% of those cases.
Magnetic resonance urography is reliable in differentiating calyceal diverticula from renal cysts. On MRU, all diverticula were identified within 15 min of contrast administration; hence longer delays in imaging are unnecessary.

BACKGROUND: Calyceal diverticula (CD) are abnormally dilated calyces caused by a narrowed infundibulum. Although rare, with incidence rates previously reported between 0.21% and 0.45%, CD pose diagnostic dilemmas in children as they mimic other cystic lesions of the kidney with different etiologies. Calyceal diverticula can become symptomatic if they become a locus for infections and stone formation, and the optimal treatment strategy is currently undefined.
OBJECTIVE: The aim of the study is to present a large series of consecutive cases of pediatric CD and investigate the authors\' hypothesis that CDs are more common than previously reported, size of the lesion drives intervention, and laparoscopic ablation is the most effective intervention.
METHODS: The authors conducted an observational case-control survey by reviewing all cases of pediatric CD through a prospectively maintained database of renal cystic lesions at their institution between 2012 and 2018. They analyzed the clinical and radiological presentation and description of symptoms with particular emphasis on the outcomes of ureteroscopic or laparoscopic surgical interventions.
RESULTS: Of 757 renal cysts evaluated in the pediatric urology clinics at the authors\' institution, there were 43 (5%) cases of CD confirmed by cross-sectional imaging or retrograde pyelogram. The median age was 12 years. There was a female preponderance (67%), and 14% were bilateral. Twenty-five of 43 children underwent surgery (58%). On multivariate analysis, the size/complexity of the cyst (odds ratio = 2.13, 1.02 to 4.4, P = 0.04) and the presence of pain (5.931, 1.36 to 25.87, P = 0.018) were found to correlate with the need for intervention. Ureteroscopic intervention (i.e., balloon dilatation, laser incision, or diathermy incision) was the most used index procedure (17/25), followed by laparoscopic ablation (6/25), with success rates of 40% and 100%, respectively (P = 0.01). Complications in either of the approaches were usually mild and similar (P = 0.63). The majority of ureteroscopic interventions required multiple sessions (11/17, 65%, median = 2 major procedures) to achieve resolution, whereas none in the laparoscopic group required a second procedure. There were a total of 30 ureteroscopic and 8 laparoscopic approaches.
CONCLUSIONS: The authors demonstrate that CD comprise at least 5% of cystic lesions and that CD size and pain at presentation predict intervention in 60% of children diagnosed at their institution. Laparoscopic ablation is the optimal treatment and has significantly higher success rates than the ureteroscopic approach.

Calyceal diverticula outpouchings that occur rarely in the upper collecting system of the kidney and is often difficult to detect. In this study, we present two cases of calyceal diverticula and discuss their clinical characteristics and radiologic features.
In the presented two cases, we applied several imaging examinations, including delayed intravenous pyelography, retrograde pyelography and axial computerized tomographic (CT) scanning of the kidneys with and without contrast. Serum creatinine levels in fluid withdrawn from the diverticula were found to be significantly higher than the simultaneous serum creatinine levels. Intravenous injection of methylene blue through a ureteral catheter was also aided in the diagnosis. Calyceal diverticulum neck dilatation was performed through a percutaneous nephroscope.ResultsThe two cases were diagnosed preoperatively and the operation was successful performed. The nephrostomy tube was removed seven days after surgery without complications. CT scans of the kidney after six months showed that the size of the calyceal diverticulum of two patients were considerably smaller than pre-surgery. There were no reports of pain in the lumbar region or other discomfort.
Diagnosis of calyceal diverticulum mainly depend on a variety of imaging examinations, including the delayed intravenous pyelography, retrograde pyelography, and kidney CT plain scan plus enhanced scan. If the patient cannot be diagnosed by above methods, cyst fluid can be aspirated percutaneously to measure the preoperative creatinine level. If it is significantly higher than the serum creatinine level, the cyst fluid is considered urine, which can assist in the diagnosis of calyceal diverticulum. A ureteral catheter should also be inserted before operation namely, intravenous injection of methylene blue through a ureteral catheter is helpful for diagnosis. The choice of surgical treatment is based on the size and location of calyceal diverticulum and clinical manifestations.

OBJECTIVE: Calyceal diverticula are rare entities that can pose a significant challenge when it comes to their management. We analyse and summarise the literature with a focus on recent advances in the management of calyceal diverticula and discuss the advantages and disadvantages of each surgical technique.
RESULTS: The identification of calyceal diverticula requires a certain level of suspicion and contrast-enhanced imaging. Conventional techniques of imaging the renal collecting system such as the classic intravenous urography are now superseded by the ease of access to contrast-enhanced CT imaging. Conventional surgical techniques for managing calyceal diverticula are not being superseded by new techniques but rather being progressively enhanced and improved through the amelioration of existing technology. Debate still exists over the best treatment approach for the management of symptomatic calyceal diverticula, the choice of which still very much depends on the location and anatomy of the diverticulum itself. The most significant advance in the management of calyceal diverticula and indeed stones, in general, seems to be the progressive miniaturisation of percutaneous nephrolithotomy (PCNL) equipment allowing effective treatment with a reduction in associated risks of conventional PCNL. The increasing accessibility of robotics has a role to play in the management of this condition but is not likely surpass flexible ureteroscopic (fURS) or percutaneous approaches. The future of surgical management for this condition lies in striking a balance between treatment efficacy and invasiveness. More recent identification of metabolic disturbances in patients with calyceal diverticular stones may provide further insights into the underlying pathology of this condition and is likely to play a role in future research of diverticular stones.

BACKGROUND: Incidence of simultaneous renal cyst with calyceal diverticula in contralateral kidney is rare in children. A minimally invasive procedure in different sittings is often recommended.
METHODS: A Chinese 15-month-old boy presented to the Urology department of a tertiary care center with right flank pain. He was subjected to magnetic resonance urography and was diagnosed as having right renal cyst and contralateral calyceal diverticula. He underwent robotic cyst decortication and calyceal diverticulectomy using da Vinci robot. His postoperative period was uneventful. He was discharged on fifth postoperative day. Histopathology was consistent with simple renal cyst.
CONCLUSIONS: Robotic combined cyst decortication and contralateral diverticulectomy is feasible in selected small children. However, it demands adequate technical skill and experience.

Calyceal diverticula are rare outpouchings of the upper collecting system lying within the renal parenchyma. These often contain stones, however, carcinoma within a calyceal diverticulum is uncommon. The present study reports a case of invasive urothelial carcinoma within a calyceal diverticulum associated with renal stones. A 70-year-old male with a left renal mass identified by abdominal computed tomography was referred to the Department of Urology, Kanazawa University Hospital. Pre-operative diagnosis was difficult owing to an atypical imaging finding of a hypovascular renal mass with calcification. A laparoscopic nephroureterectomy was performed, and the surgical specimens showed invasive high-grade urothelial carcinoma within a calyceal diverticulum, and the calcifications were renal stones consisting of 97% calcium oxalate. Urothelial carcinoma in calyceal diverticula is a rare condition, however, a pre-operative definite diagnosis is difficult and a high potential for invasion of the renal parenchyma is suspected in this disease.

Calyceal diverticula are rare outpouchings of the upper collecting system that likely have a congenital origin. Stones can be found in up to 50% of calyceal diverticula, although, over the combined reported series, 96% of patients presented with stones. Diagnosis is best made by intravenous urography or computed tomography urogram. Shock wave lithotripsy (SWL) is an option for first-line therapy in patients with stone-bearing diverticula that have radiologically patent necks in mid- to upper-pole diverticula and small stone burdens. Stone-free rates are the lowest with SWL, although patients report being asymptomatic following therapy in up to 75% of cases with extended follow-up. Ureteroscopy (URS) is best suited for management of anteriorly located mid- to upperpole diverticular stones. Drawbacks to URS include difficulty in identifying the ostium and low rate of obliteration. Percutaneous management is best used in posteriorly located mid- to lower-pole stones, and offers the ability to directly ablate the diverticulum. Percutaneous nephrolithotomy remains effective in the management of upperpole diverticula, but carries the risk of pulmonary complications unless subcostal access strategies such as triangulation or renal displacement are used. Laparoscopic surgery provides definitive management, but should be reserved for cases with large stones in anteriorly located diverticula with thin overlying parenchyma, and cases that are refractory to other treatment. This article reviews the current theories on the pathogenesis of calyceal diverticula. The current classification is examined in addition to the current diagnostic methods. Here we summarize an extensive review of the literature on the outcomes of the different treatment approaches.