Reflex anuria: an old concept with new evidence

Risk stratification of acute kidney injury (AKI) following ureteral stent insertion for colorectal surgery

INTRODUCTION AND OBJECTIVES

Ureteral stents have long been utilized during colorectal resections to assist in the identification of ureters intraoperatively and mitigate risk of ureteral injury. As these procedures have shifted toward robot-assisted laparoscopic methods, lighted stents have increasingly been used. The incidence of acute kidney injury (AKI) following bilateral ureteral stent placement has been reported to be as high as 41.9%. We sought to identify our single-institution risk and determine the extent to which age, sex, and stent type affected incidence of AKI.

METHODS

A retrospective analysis was performed at a single community hospital of all open and robotic-assisted laparoscopic colorectal surgeries from October 2012 to April 2022. If requested, ureteral stents were placed bilaterally by a urologist and later removed by the surgeon. Non-lighted stents used were 5 Fr whistle-tip (BARD); lighted stents were 6 Fr with a fiberoptic core (STRYKER). Kidney failure was described as a rise of creatinine to ≥ 1.5 times the preoperative value, per KDIGO guidelines.

RESULTS

633 consecutive colorectal surgeries were evaluated, with no stents placed in 237 cases, non-lighted stents placed in 137 cases, and lighted stents placed in 259 cases. No ureteral injuries were observed. Overall incidence of AKI for non-stented surgeries was 0.8% vs 5.8% for non-lighted stents and 5.8% for lighted stents. Patient age was the most significant factor in AKI incidence: for patients under 60, there was no statistical difference in AKI incidence for stented vs non-stented procedures (2.2% vs 1.1%). For patients over 60, the risk of AKI was 10.5% for stented vs 0.7% for non-stented. Female patients had statistically significant risk differences, with AKI incidence of 7.1% stented vs 0.0% non-stented. AKI completely resolved in all cases, regardless of cohort.

CONCLUSIONS

In patients under age 60, the use of stents was not associated with an increased risk of AKI. For women and those over 60, stents pose a higher risk of transient AKI. Overall incidence of AKI in our larger and single-institution community hospital population was significantly lower than reported in other studies. No statistical difference was observed, overall, in AKI incidence between lighted and non-lighted stents.

The Rho-kinase inhibitor Y27632 promotes ureteral relaxation in an in vivo rat model for partial ureteral obstruction

PURPOSE

Aim of this study was to evaluate the effect of intravenous Y27632 (a ROK inhibitor) on intra-ureteral pressures and on blood pressure in an in vivo rat model for unilateral partial ureteral obstruction (PUO).

METHODS

15 Male Sprague Dawley rats were used. Under isofluran anesthesia, saline was continuously infused via polyethylene (PE)-10 catheters inserted in the ureters beneath the kidney pelvis. Left psoas muscle was sutured around the distal left ureter to create a partial obstruction. Carotid artery and femoral vein were cannulated with PE catheters for registration of mean arterial blood pressure (MAP) and for administration of drugs. Left and right ureter pressures and MAP were simultaneously recorded. Y27632 (0.03 and 0.1 mg/kg each n = 6-7) was given intravenously. T-test was used for comparisons.

RESULTS

Spontaneous peristaltic pressure waves were recorded at baseline for both ureters. After the obstruction, Y27632 reduced maximum pressure (MaxP) by 10.5 ± 1.9% (0.03 mg/kg; p = 0.004) and 29.1 ± 4.8% (0.1 mg/kg; p < 0.001), minimum pressure (MinP) by 5.2 ± 2.3% (0.03 mg/kg; p = 0.02) and 12.2 ± 3.4% (0.1 mg/kg; p = 0.009), the area under the curve (AUC) by 7.8 ± 2.4% (0.03 mg/kg; p = 0.008) and 16.5 ± 3.7% (0.1 mg/kg;p = 0.007), the waves amplitude by 23.4 ± 11.3% (0.03 mg/kg; p = 0.098) and 38.7 ± 7.5% (0.1 mg/kg; p < 0.001), with no effect on contraction frequency. During simultaneous recordings from the normal ureter at the investigated doses, Y27632 reduced MaxP, MinP, AUC and waves amplitude by 1-7%. The MAP was reduced by 12.5 ± 5.3% (0.03 mg/kg; p = 0.07) and 15.8 ± 1.8% (0.1 mg/kg; p < 0.001).

CONCLUSIONS

Y27632 decreased intra-ureteral pressures of a partially obstructed ureter with limited effect on blood pressure in an animal model of unilateral PUO.

Primary versus deferred ureteroscopy for the management of obstructive anuria secondary to ureteric urolithiasis in children: a prospective randomized study

To compare the role of primary and deferred ureteroscopy (URS) in the management of obstructive anuria secondary to ureteric urolithiasis in pediatric patients. This prospective randomized study included 120 children aged ≤ 12 years who presented with obstructive anuria secondary to ureteric urolithiasis between March 2019 and January 2021. The children were subdivided into group A, which included children who had undergone primary URS without pre-stenting, and group B, which included children who had undergone URS after ureteric stenting. All children were clinically compensated and sepsis-free. Patients with underlying urological structural abnormalities were excluded. The operative time, improvement of renal functions, stone-free rate, and complications were compared between the two groups. At the 1-month follow-up, urine analysis; kidney, ureter, and bladder radiography; and ultrasonography were performed. The patient characteristics of both groups did not show any significant difference. Primary URS had failed in ten children (16.6%) in group A. Moreover, failure of stenting was noted in six patients (11%) in group B. The mean operative time for group B was significantly lower than that for group A (p ≤ 0.001). The stone-free rate was significantly higher in group B (p ≤ 0.001). The rate of overall complications was higher in group A. Deferred URS is preferable over primary URS in the management of obstructive anuria secondary to ureteric urolithiasis". In children because of the lower need for ureteric dilatation, higher stone- free rate, shorter procedure time, and lower complication rate.

Complications Of Peri-Operative Ureteral Catheter Placement: Experience at A Major Cancer Center

OBJECTIVE

To evaluate risks of peri-operative ureteral catheter placement in a consecutive patient-series.

METHODS

Patients who underwent peri-operative ureteral catheter placement at a single institution in 2018 were included. A retrospective review was conducted to evaluate patient and procedure related characteristics, including data on technique, perceived placement difficulty, operative details, and complications.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Urologic complications within 30 days were evaluated using the Clavien-Dindo system. Statistical analysis for association was conducted using the X2 test or fisher's exact tests.

RESULTS

413 patients were included. 50/413 (12.1%) cases had urologic complications within 30 days. 43 were Clavien-Dindo grade I-II. Six were grade III. 5/6 patients had oliguric, obstructive AKI. One had flank pain with hydronephrosis. Two patients each underwent placement of unilateral nephrostomy tube, bilateral double-J stent placement, and unilateral stent placement. One patient had a Grade V complication. They developed multi-system organ failure including renal failure with hydronephrosis.All patients who required re-intervention had bilateral peri-operative catheterization with use of a wire. Intraoperative difficulty with placement was associated with high-grade complication (P<.01)). Limitations include retrospective,single center study design.

CONCLUSIONS

Rate of acute complication following ureteral catheter placement is 12%. 1.7% of patients develop post-operative ureteral obstruction requiring intervention within 30 days. Future studies are needed to determine patients most at risk for post-ureteral stent complication.

Reflex Anuria: A Complication of Hyperthermic Intraperitoneal Chemotherapy

Reflex anuria (RA) is a rare cause of abrupt reduction of urine output following trauma, irritation, or painful stimuli to the kidneys, ureters, or surrounding organs. The mechanism of RA is a reflex spasm of both ureters and/or renal arterioles. It is a well-documented complication of colorectal surgeries and gynecological surgeries which involve placement of a ureteric stent for ureteric identification and prevention of injury. RA and post-renal obstruction can both be complications of intraperitoneal hyperthermic chemotherapy (HIPEC) in patients who are undergoing surgery for colorectal cancer and peritoneal carcinomatosis. HIPEC procedure can lead to inflammation of the entire abdomen, including the ureters. This inflammation can result in hematuria that can form clots along the urinary tract and cause post-renal obstruction. The inflammation can also result in RA. It is essential to maintain high urine output during the early postoperative period to prevent clots and the ensuing post renal obstruction. It is also important to identify RA and maintain a low threshold to treat it by placing ureteric stents even in the absence of overt bilateral hydronephrosis.

Feasibility of injected indocyanine green for ureteral identification during robotic left-sided colorectal resections

BACKGROUND

Ureteral identification is essential to performing safe colorectal surgery. Injected immunofluorescence may aid with ureteral identification, but feasibility without ureteral catheterization is not well described.

METHODS

Case series of robotic colorectal resections where indocyanine green (ICG) injection with or without ureteral catheter placement was performed. Imaging protocol, time to ureteral identification, and factors impacting visualization are reported.

RESULTS

From 2019 to 2020, 83 patients underwent ureteral ICG injection, 20 with catheterization and 63 with injection only. Main indications were diverticulitis (52%) and cancer (36%). Median time to instill ICG was faster with injection alone than with catheter placement (4min vs 13.5min, p < 0.001). Median time [IQR] to right ureter (0.3 [0.01-1.2] min after robot docking) and left ureter (5.5 [3.1-8.8] min after beginning dissection) visualization was not different between injection alone and catheterization.

CONCLUSION

ICG injection alone is faster than with indwelling catheter placement and equally reliable at intraoperative ureteral identification.

Treatment management of COVID-19 positive patients with renal colic secondary to distal ureteral stone

OBJECTIVE

In this study, we aimed to contribute to the literature by sharing and evaluating the clinical characteristics and our treatment and follow-up approaches in patients in the COVID-19 positive treatment process who had presented to our hospital's emergency department with a distal ureteral stone and to examine the effects of the pandemic and disease in this group of patients.

METHOD

The study included 14 patients infected with COVID-19 who had presented to the Erzurum City Hospital Emergency Department between August 2020 and December 2020 with the complaint of renal colic in which distal ureteral stones were detected in the tests. The demographic and clinical characteristics of patients, laboratory and radiological examinations, characteristics of ureteral stones, details of treatments applied to patients, treatment procedures of patients who had undergone surgical treatment, patient files, visit and operation notes and the patient discharge reports were retrospectively reviewed and evaluated.

RESULTS

The study included 14 patients. The average age of the patients was 35.7 (±14.35). The average stone size was 6.2 (±1.8) mm. Analgesic treatment and MET for distal ureteral stones were begun in 11 (78.6%) of the patients. Pain control was achieved in nine patients (64.2%) with analgesic treatment and MET, and the stone was removed without invasive intervention. Surgical intervention was performed in a total of five patients (35.7%).

CONCLUSION

In most COVID-19 infected patients with renal colic and a distal ureteral stone, results can be obtained using MET. Patients with a distal ureteral stone and persistent renal colic can be safely and effectively treated by endoscopic ureteral stone treatment after taking necessary precautions. Prospective, randomised, and controlled studies are required on this subject.

Reflex Anuria Following Retrograde Pyelography: A Case Report and Literature Review

A case of acute kidney injury due to reflex anuria that was caused by retrograde pyelography and required temporary hemodialysis is reported. An 83-year-old Japanese woman presented with anuria 2 days after undergoing bilateral retrograde pyelography for the investigation of gross hematuria. Retrograde pyelography showed no apparent abnormality, such as malignancy or urolithiasis, but pyelorenal extravasation of contrast medium was remarkable. Her anuria improved promptly after hemodialysis, allowing her treatment to conclude with only one hemodialysis session, and a normal renal function was restored with no sequelae. The details of this case and a review of the relevant literature are presented.

Reflex anuria post-prophylactic bilateral ureteric catheterisation: a rare postoperative complication

We highlight the case of a woman who had elective gynaecological surgery with bilateral prophylactic ureteric catheterisation, indicated for the excision of a mucinous cystadenoma arising from the right ovary. Surgery was successful with no intraoperative complications. Anuria and subsequent acute kidney injury developed within 12 hours of surgery. A CT of the kidneys, ureters and bladder revealed mild bilateral hydronephrosis and perinephric stranding surrounding the left kidney with no discernible injury to the lower urinary tract. Further investigation did not reveal a clear cause for her anuric state. Management involved aggressive renal support, rigid cystoscopy and bilateral ureteric stenting. Diuresis and a prompt improvement in renal function ensued with no further complications. She was discharged a week after her initial operation, with a 6-week review for stent removal. We believe this to be a rare instance of reflex anuria due to ureteric spasm and encourage consideration of ureteric stenting as part of subsequent management.

Primary versus deferred ureteroscopy for management of calculus anuria: a prospective randomized study

Introduction

Obstructive anuria can be managed by primary ureteroscopy (URS) or deferred URS after initial ureteral stenting. We want to compare the primary URS and deferred URS in the management of calculus anuria regarding the feasibility and clinical outcome.

Material and methods

Between January 2012 and December 2014, 150 patients with anuria due to ureteral calculi were prospectively randomized according to the timing of ureteroscopic intervention into two groups; deferred URS group (69 patients who were treated initially by ureteral stenting) and primary URS group (81 patients who were treated by emergency URS). Follow-up was at least 6 months postoperatively.

Results

Complete stone clearance was 87 % and 75.3% for deferred and primary URS groups, respectively (p = 0.097). Renal function normalized in 94.2% of deferred URS vs. 97.5% of primary URS (p = 0.414). Deferred URS group had a 2.9 % overall complication rate in comparison to 9.9 % for the primary URS group (p = 0.109). Ureteral perforation/pyelonephritis was noted in 6.2% of the primary URS group only (p = 0.043). The median number of maneuvers required until stone clearance was one (range 1–5) for primary URS vs. two (range 2–3) for deferred URS (p <0.001). The cost of primary URS was significantly less (p <0.001). On a multivariate analysis, lower ureteral calculi (OR 13.03, 95% CI 4.07– 41.7, p <0.001) and deferred URS (OR 2.84, 95% CI 1.07–7.49, p = 0.035) were independent predictors for an eventless and successful URS.

Conclusions

Primary URS for calculus anuria is feasible and cost-effective. It has a short hospital stay, but is still technically demanding. The perioperative complications are comparable to URS in normouric patients.

Experience of a Tertiary-Level Urology Center in the Clinical Urological Events of Rare and Very Rare Incidence. III. Psychourological Events: 1. Psychic Anuria

INTRODUCTION

Psychic anuria is an old term, referring to a very rare psycho-urological event that has scarcely been studied so far.

MATERIALS AND METHODS

A retrospective study of the patients with psychic anuria presented to Assiut Urology and Nephrology Hospital during the period July 1991-June 2016 was done. Psychic anuria was defined, and the demographic and clinical characteristics including the methods of diagnosis and management were studied.

RESULTS

Of more than 3,800 cases of anuria, 9 female patients (0.24%) experienced psychic anuria in the age range of 17-43 years. Cardinal clinical findings included anuria for 36-72 h with absence of organic causes and normal renal function tests. Psychosocial risk factors were reported in the 9 cases. Anuria was documented by reliable history (56%) or observable urine collection (44%). Diagnosis was done by exclusion, where the investigations revealed no organic causes. Seven cases responded to the placebo intervention and 2 cases were self-limiting and resolved spontaneously.

CONCLUSIONS

Psychic anuria is an extremely rare urological emergency that presents, mainly, in young adult females with unknown mechanisms. Renal vasoconstriction following psychosocial stressors is suggested. It is diagnosed by exclusion and resolves spontaneously or responds to placebo intervention as a mental distraction technique.

Ureteral stents increase risk of postoperative acute kidney injury following colorectal surgery

BACKGROUND

Ureteral stents are commonly placed before colorectal resection to assist in identification of ureters and prevent injury. Acute kidney injury (AKI) is a common cause of morbidity and increased cost following colorectal surgery. Although previously associated with reflex anuria, prophylactic stents have not been found to increase AKI. We sought to determine the impact of ureteral stents on the incidence of AKI following colorectal surgery.

METHODS

All patients undergoing colon or rectal resection at a single institution between 2005 and 2015 were reviewed using American College of Surgeons National Surgical Quality Improvement Program dataset. AKI was defined as a rise in serum creatinine to ≥ 1.5 times the preoperative value. Univariate and multivariate regression analyses were performed to identify independent predictors of AKI.

RESULTS

2910 patients underwent colorectal resection. Prophylactic ureteral stents were placed in 129 patients (4.6%). Postoperative AKI occurred in 335 (11.5%) patients during their hospitalization. The stent group demonstrated increased AKI incidence (32.6% vs. 10.5%; p < 0.0001) with bilateral having a higher rate than unilateral stents. Hospital costs were higher in the stent group ($23,629 vs. $16,091; p < 0.0001), and patients with bilateral stents had the highest costs. Multivariable logistic regression identified predictors of AKI after colorectal surgery including age, procedure duration, and ureteral stent placement.

CONCLUSIONS

Prophylactic ureteral stents independently increased AKI risk when placed prior to colorectal surgery. These data demonstrate increased morbidity and hospital costs related to usage of stents in colorectal surgery, indicating that placement should be limited to patients with highest potential benefit.

Reflex anuria: a rare cause of acute kidney injury

Background

Acute Kidney Injury results from pre renal, post renal or intrinsic renal causes. Reflex anuria is a very rare cause of renal impairment which happens due to irritation or trauma to one kidney or ureter, or severely painful stimuli to other nearby organs.

Case Presentation

Here we present a case of acute kidney injury secondary to reflex anuria in a patient who underwent extensive gynecological surgery along with ureteral manipulation which recovered spontaneously.

Conclusion

Reflex Anuria is a rare and often not considered as cause of acute kidney injury. This case illustrates that this should be kept as a differential in potential cause of acute kidney injury in patient undergoing urogenital or gynecological surgeries.