Metabolic changes after urinary diversion

Marked Metabolic Acidosis Due to a Transverse Stoma after Urethroplasty for Congenital Epispadias

A 58-year-old woman was admitted to our hospital. At 10 years old, she had undergone bilateral uretero-sigmoid anastomosis for congenital epispadias, and at 57 years old, she had received transverse colostomy. Biochemical tests showed marked metabolic acidosis. Computed tomography showed urine stagnation in the sigmoid colon, leading to a diagnosis of metabolic acidosis associated with transverse stoma after bilateral uretero-sigmoid anastomosis. Her bone mineral density was below normal, and the bone metabolic marker levels were high, indicating high-turnover osteoporosis. Both metabolic acidosis and bone metabolism were stabilized by treatment with a transanal urinary catheter, sodium bicarbonate, and vitamin D.

The Incidental Discovery of an Ileal Conduit Calculus: A Case Report

In patients who have undergone radical cystectomy, urinary diversion procedures such as ileal conduits may pose a considerable problem for urologists when they result in stone formation. While an ileal conduit stone is only one of many potential complications of this procedure, its management may be particularly challenging; symptoms and treatments vary depending on factors such as stone location, composition, and the patient's BMI. We present a unique case of a 91-year-old male with a history of prostate and bladder cancer status post-radical prostatectomy, cystectomy, and ileal conduit who presented to the emergency department complaining of abdominal pain, nausea, vomiting, and disorientation for the last 24 hours. The patient was diagnosed with a complete bowel obstruction secondary to gallstone ileus. Consequently, an exploratory laparotomy was performed, which revealed that his small bowel obstruction was not caused by gallstone ileus but rather secondary to an internal hernia and volvulus associated with a previous bowel resection and anastomosis. The stone that was originally thought to be causing the small bowel obstruction turned out to be a 3.3 cm stone in his ileal conduit, which ultimately had no part in causing the patient's small bowel obstruction. Calculus formation is an infrequent complication of ileal conduit placement. Our aim in presenting this case is to increase awareness of this rare complication that can arise without symptoms with the hopes of increasing early intervention and improving outcomes.

Radical cystectomy and urinary diversion outcomes in patients with single vs. double renal unit: A 2:1 matched-pair analysis

OBJECTIVE

To evaluate perioperative and functional outcomes of radical cystectomy (RC) and urinary diversion (UD) in patients with a single kidney (SK) vs. double kidneys (DK).

METHODS

We reviewed records of patients who underwent RC for bladder cancer with a history of prior or concurrent nephrectomy at USC between 2004 and 2020. Patients with chronic kidney disease who were already on dialysis were excluded. UD, perioperative complications, and postoperative glomerular filtration rate (GFR) of the SK group were compared with a group of patients who underwent RC with DK using 2:1 matching with respect to age, sex, preop GFR, and tumor stage.

RESULTS

We included 186 patients (SK = 62 and DK = 124). Half of the SK patients underwent continent UD. SK patients had a higher length of hospital stay compared to the DK group; however, 90-day complications, readmission, and mortality rates were similar. In patients with continent diversion, SK vs. DK showed similar 90-day complications (71% vs. 69%, P = 1.0). SK patients had significantly lower GFRs at discharge, 3-, and 12-month following RC compared to the DK group. Postoperative GFRs of the SK patients with continent vs. incontinent UD were statistically similar. On multivariable analysis, UD (i.e. continent vs. incontinent) was not associated with post-op GFR decline at discharge, 3- and 12-month following RC.

CONCLUSIONS

Perioperative outcomes of radical cystectomy patients with single kidney are similar to double kidney patients, except for more GFR decline in single kidney cases. Continent urinary diversion in single kidney is as safe as double kidney patients.

Hypokalaemic quadriparesis in a patient with urinary diversion through Indiana pouch

A man in his 20s, a patient with chronic kidney disease with a baseline estimated glomerular filtration rate of 33 mL/min/1.73 m2, who had an Indiana pouch continent urinary diversion procedure done at 6 years of age for bladder exstrophy, presented to the emergency room with sudden-onset progressive quadriparesis over 6 hours with power 1/5 in all the limbs with preserved reflexes. He was fully conscious and oriented, with stable vital signs. On evaluation, he had severe hypokalaemia and severe metabolic acidosis (both high anion gap and non-anion gap acidosis). Imaging studies showed bilateral gross hydroureteronephrosis, and renal and pouch calculi. Hypokalaemia was promptly treated with intravenous potassium chloride and acidosis with emergency haemodialysis. The patient had a complete motor recovery following intravenous potassium correction and was discharged with oral potassium and bicarbonate supplements. Here, the Indiana pouch, its metabolic and electrolyte complications, and its treatment are discussed.

Urinary Metabolic Markers of Bladder Cancer: A Reflection of the Tumor or the Response of the Body?

This work will review the metabolic information that various studies have obtained in recent years on bladder cancer, with particular attention to discovering biomarkers in urine for the diagnosis and prognosis of this disease. In principle, they would be capable of complementing cystoscopy, an invasive but nowadays irreplaceable technique or, in the best case, of replacing it. We will evaluate the degree of reproducibility that the different experiments have shown in the indication of biomarkers, and a synthesis will be attempted to obtain a consensus list that is more likely to become a guideline for clinical practice. In further analysis, we will inquire into the origin of these dysregulated metabolites in patients with bladder cancer. For this purpose, it will be helpful to compare the imbalances measured in urine with those known inside tumor cells or tissues. Although the urine analysis is sometimes considered a liquid biopsy because of its direct contact with the tumor in the bladder wall, it contains metabolites from all organs and tissues of the body, and the tumor is separated from urine by the most impermeable barrier found in mammals. The distinction between the specific and systemic responses can help understand the disease and its consequences in more depth.

Impact of Intestinal Urinary Diversion on the Risk of Fracture and Loss of Bone Mass: A Systematic Review

BACKGROUND

Patients undergoing intestinal urinary diversion (IUD) may have a higher risk of osteoporosis and risk of fractures due to metabolic acidosis and decrease of intestinal absorption surface.

OBJECTIVE

We performed a systematic review of the available literature on the impact of IUD on bone demineralization.

METHODS

We systematically searched PubMed®, for original articles published before April 2020. Primary end points were the risk of fracture and loss of bone density. Secondary outcomes were the metabolic changes in biochemical and urine parameters related to calcium metabolism and histological changes.

RESULTS

Our electronic search identified a total of 2417 articles. After a detailed review, we selected 11 studies that addressed the impact of IUD on bone health in 10369 patients. The risk of bone fracture was studied in 3 articles, showing a higher risk in the IUD population. Of the 9 articles evaluating the relation between intestinal urinary diversion and bone density, 5 did find a positive association. One article evaluated the bone metabolism at a cellular level after IUD showing a decrease in bone turnover in this population. Three of the eight studies reporting data on serum parameters related to calcium and phosphate metabolism showed differences. Finally, a correlation between concentration of pyridolines in urine and loss of bone density was found in two of the three studies.

CONCLUSIONS

Although published data on BMD are contradictory, patients undergoing IUD seem to be at higher risk of bone fractures. Our finding support the need to implement accessible strategies on osteoporosis screening and prevention in IUD patients.

Recurrent noncirrhotic hyperammonemia causing acute metabolic encephalopathy in a patient with a continent ileocecal pouch: a case report

Introduction

Acute encephalopathy, while a common presentation in the emergency department, is typically caused by a variety of metabolic, vascular, infectious, structural, or psychiatric etiologies. Among metabolic causes, hyperammonemia is relatively common and typically occurs in the setting of cirrhosis or liver dysfunction. However, noncirrhotic hyperammonemia is a rare occurrence and poses unique challenges for clinicians.

Case presentation

Here we report a rare case of a 50-year-old Caucasian female with history of bladder cancer status post chemotherapy, radical cystectomy, and ileocecal diversion who presented to the emergency department with severe altered mental status, combativeness, and a 3-day history of decreased urine output. Her laboratory tests were notable for hyperammonemia up to 289 μmol/L, hypokalemia, and hyperchloremic nonanion gap metabolic acidosis; her liver function tests were normal. Urine cultures were positive for Enterococcus faecium. Computed tomography imaging showed an intact ileoceal urinary diversion with chronic ileolithiasis. Upon administration of appropriate antibiotics, lactulose, and potassium citrate, she experienced rapid resolution of her encephalopathy and a significant reduction in hyperammonemia. Her hyperchloremic metabolic acidosis persisted, but her hypokalemia had resolved.

Conclusion

This case is an example of one of the unique consequences of urinary diversions. Urothelial tissue is typically impermeable to urinary solutes. However, when bowel segments are used, abnormal absorption of solutes occurs, including exchange of urinary chloride for serum bicarbonate, leading to a persistent hyperchloremic nonanion gap metabolic acidosis. In addition, overproduction of ammonia from urea-producing organisms can lead to abnormal absorption into the blood and subsequent oversaturation of hepatic metabolic capacity with consequent hyperammonemic encephalopathy. Although this is a rare case, prompt identification and treatment of these metabolic abnormalities is critical to prevent severe central nervous system complications such as altered mental status, coma, and even death in patients with urinary diversions.

[Metabolic acidosis in neobladder patients : Risk factors and treatment options]

BACKGROUND

In cystectomy patients who underwent neobladder creation, the intestinal mucosa of the neobladder is in constant contact with urine, which may result in chronic metabolic acidosis (CMA) due to specific absorption capabilities of the intestinal mucosa. Despite being a prevalent comorbidity, the risk factors for CMA and its diagnostic parameters are poorly understood.

OBJECTIVES

This review examines the risk factors associated with the development of CMA and their prevalence in patients with a neobladder.

MATERIALS AND METHODS

We conducted a systematic literature search using the PubMed database to detect studies about the topics CMA and neobladder that were published between 2000 and 2020. The prevalence and risk factors for CMA in neobladder patients were assessed by reviewing 23 studies.

RESULTS

Acidosis is most prevalent during the first year after surgery (25-70%). Risk factors are renal failure, high continence, old age and diabetes mellitus.

CONCLUSIONS

The prevalence of CMA is at its highest during the early postoperative period for neobladder patients, so for this time period, weekly diagnostic investigations are recommended according to the German S3-guidelines for the "Früherkennung, Diagnose, Therapie und Nachsorge des Harnblasenkarzinomsent für Neoblasepatienten". Blood gas tests should not only be used to analyze the pH value but also to detect and counteract acid-base imbalance issues in time. The recommended normalization of serum bicarbonate levels with oral bicarbonate follows patient-specific therapy strategies.

Anesthetic considerations for urologic surgeries

Urologic surgeries are widely performed, and the cases have increased owing to the fact that the elderly population is growing. The narrow and limited surgical space is a challenge in performing most urologic surgeries. Additionally, the elderly population is exposed to the risk of perioperative complications; therefore, a comprehensive understanding and approach are required to provide optimized anesthesia during surgery. We have searched the literature on anesthesia for urologic surgeries and summarized the anesthetic considerations for urologic surgeries.

Use of an acellular collagen-elastin matrix to support bladder regeneration in a porcine model of peritoneocystoplasty

Introduction

Bladder reconstruction without using the intestine remains a challenge to this day despite the development of new biomaterials and cell cultures. Human bladder engineering is merely anecdotic, and mostly in vitro and animal studies have been conducted.

Material and methods

In our study using a porcine model, we performed a bladder augmentation using an autologous parietal peritoneum graft (peritoneocystoplasty) and determined whether the attachment of an acellular collagen-elastin matrix (Group 1) or lack of (Group 2) had better histologic and functional results. Thus far, peritoneocystoplasty has rarely been performed or combined with a biomaterial.

Results

After 6 weeks, we observed different degrees of retraction of the new bladder wall in both groups, although the retraction was lower and the histological analysis showed more signs of regeneration (neoangiogenesis and less fibrosis) in Group 1 than when compared with Group 2. No transitional cells were found in the new bladder wall in any of the groups, and no differences were observed in the functional test results.

Conclusions

Performing a peritoneocystoplasty is an easy and safe procedure. The data supports the benefit of an acellular collagen–elastin matrix to reinforce bladder regeneration. However, in our study we observed too much retraction of the new wall and the histologic results were not acceptable to consider it an appropriate cystoplasty technique.

Current status of tissue engineering applied to bladder reconstruction in humans

CONTEXT AND OBJECTIVE

Bladder reconstruction is performed to replace or expand the bladder. The intestine is used in standard clinical practice for tissue in this procedure. The complications of bladder reconstruction range from those of intestinal resection to those resulting from the continuous contact of urine with tissue not prepared for this contact. In this article, we describe and classify the various biomaterials and cell cultures used in bladder tissue engineering and reviews the studies performed with humans.

ACQUISITION OF EVIDENCE

We conducted a review of literature published in the PubMed database between 1950 and 2017, following the principles of the PRISM declaration.

SYNTHESIS OF THE EVIDENCE

Numerous in vitro and animal model studies have been conducted, but only 18 experiments have been performed with humans, with a total of 169 patients. The current evidence suggests that an acellular matrix, a synthetic polymer with urothelial and autologous smooth muscle cells attached in vitro or stem cells would be the most practical approach for experimental bladder reconstruction.

CONCLUSIONS

Bladder replacement or expansion without using intestinal tissue is still a challenge, despite progress in the manufacture of biomaterials and the development of cell therapy. Well-designed studies with large numbers of patients and long follow-up times are needed to establish an effective clinical translation and standardisation of the check-up functional tests.

Tissue-Engineered Neo-Urinary Conduit from Decellularized Trachea

Decellularized tissues have been increasingly popular for constructing scaffolds for tissue engineering applications due to their beneficial biological compositions and mechanical properties. It is therefore natural to consider decellularized trachea for construction of tissue-engineered trachea, as well as other tubular organs. A Neo-Urinary Conduit (NUC) is such a tubular organ that works as a passage for urine removal in bladder cancer patients who need a urinary diversion after their diseased bladder is removed. In this study, we report our findings on the feasibility of using a decellularized trachea for NUC applications. As a NUC scaffold, decellularized trachea provides benefits of having not only naturally occurring biological components but also having sufficient mechanical properties and structural integrity. We, therefore, decellularized rabbit trachea, evaluated its mechanical performance, and investigated its ability to support in vitro growth of human smooth muscle cells (hSMCs) and human urothelial cells (hUCs). The decellularized trachea had appropriate biomechanical properties with ultimate tensile strength of ∼0.34 MPa in longitudinal direction and ∼1.0 MPa in circumferential direction and resisted a radial burst pressure of >155 mm Hg. Cell morphology study by scanning electron microscopy further showed that hUCs grown on decellularized trachea adopted a typical flatten and interconnected network structure in the lumen of the scaffold, while they formed a round spherical shape and did not spread on the outer surfaces. SMCs, on the other hand, spread well throughout the scaffold. The gene expression analysis by real time quantitative polymerase chain reaction (RT-qPCR) and immunofluorescence studies further confirmed scaffold's ability to support long-term growth of hSMCs. Since uroepithelium has been shown to regenerate itself over time in vivo, these findings suggest that it is possible to construct a NUC from decellularized trachea without any preseeding of UCs. In future, we plan to translate decellularized trachea in a preclinical animal model and evaluate its biological performance.

Follow-up Management of Cystectomy Patients

Bladder cancer is the sixth leading cancer in the United States. Radical cystectomy is a lifesaving procedure for bladder cancer with or without muscle invasion. Radical cystectomy is performed on 39% of these patients, and 35% will have a life-threatening recurrence. Distant metastases are the most common; local, upper tract, and urethral recurrence can also occur. Surveillance after cystectomy is critical to diagnosing recurrence early. Functional complications after urinary diversion include bowel dysfunction, vitamin B12 deficiency, acidosis, electrolyte abnormalities, osteopenia, nephrolithiasis, urinary tract infections, renal functional decline, and urinary obstruction, which can be reversed when diagnosed early.

Urinary Tissue Engineering: Challenges and Opportunities

INTRODUCTION

In this review, we discuss major advancements and common challenges in constructing and regenerating a neo-urinary conduit (NUC). First, we focus on the need for regenerating the urothelium, the hallmark the urine barrier, unique to urinary tissues. Second, we focus on clinically feasible scaffolds based on decellularized matrices and molded collagen that are currently of great research interest.

AIM

To discuss the major advancements in constructing a tissue-engineered NUC (TE-NUC) and the challenges involved in their successful clinical translation.

METHODS

A comprehensive search of peer-reviewed literature from PubMed and Google Scholar on subjects related to urothelium regeneration, decellularized tissue matrices, and collagen scaffolds was conducted.

MAIN OUTCOME MEASURE

We evaluated the main biological and mechanical functions of urinary tissues, the need for TE implants to create a urinary diversion, the reasons for their failures in clinical settings, and the applications of decellularized tissue matrices and collagen-based molded scaffolds in their regeneration.

RESULTS

It is necessary to create a urine barrier that prevents urine leakage into the stroma that can cause failure of the graft. Despite the regeneration potential of the urothelium, the limited supply of healthy urothelial cells in patients with bladder cancer remains a major challenge. In this context, alternative strategies, such as transdifferentiation of cells into urothelium or engineered scaffolds based on decellularized tissues and molded collagen with robust urine barrier properties, are active areas of research.

CONCLUSION

There is an immediate need for developing a functional TE-NUC that can improve the quality of life of patients with bladder cancer. It is possible to achieve a TE-NUC by bioengineering an implant that has appropriate biological and mechanical properties to store and transport urine. We anticipate that future advancements in urothelium regeneration and material design will lead us closer to successful neo-urinary tissue constructs. Singh A, Bivalacqua TJ, Sopko N. Urinary Tissue Engineering: Challenges and Opportunities. Sex Med Rev 2018;6:35-44.

Metabolic and Electrolyte Abnormalities Related to Use of Bowel in Urologic Reconstruction

Many urologic reconstructive techniques involve the use of autologous bowel for urinary diversion and bladder augmentation. The resection of bowel and its reimplantation into the urinary system often comes with a variety of metabolic and electrolyte derangements, depending on the type of bowel used and the quantity of urine it is exposed to in its final anatomic position. Clinicians should be aware of these potential complications due to the serious consequences that may result from uncorrected electrolyte disturbances. This article reviews the common electrolyte complications related to both bowel resection and the interposition of bowel within the urinary tract.

Treatment of Non-Metastatic Muscle-Invasive Bladder Cancer: AUA/ASCO/ASTRO/SUO Guideline

PURPOSE

This multidisciplinary, evidence-based guideline for clinically non-metastatic muscle-invasive bladder cancer focuses on the evaluation, treatment and surveillance of muscle-invasive bladder cancer guided toward curative intent.

MATERIALS AND METHODS

A systematic review utilizing research from the Agency for Healthcare Research and Quality as well as additional supplementation by the authors and consultant methodologists was used to develop the guideline. Evidence-based statements were based on body of evidence strengths Grade A, B or C and were designated as Strong, Moderate and Conditional Recommendations with additional statements presented in the form of Clinical Principles or Expert Opinions.

RESULTS

For the first time for any type of malignancy, the American Urological Association, American Society of Clinical Oncology, American Society for Radiation Oncology and Society of Urologic Oncology have formulated an evidence-based guideline based on a risk-stratified clinical framework for the management of muscle-invasive urothelial bladder cancer. This document is designed to be used in conjunction with the associated treatment algorithm.

CONCLUSIONS

The intensity and scope of care for muscle-invasive bladder cancer should focus on the patient, disease and treatment response characteristics. This guideline attempts to improve a clinician's ability to evaluate and treat each patient, but higher quality evidence in future trials will be essential to improve level of care for these patients.

Acid-base disorders after orthotopic bladder replacement: comparison of an ileal neobladder and an ileal conduit

Objectives: For many years, creation of an orthotopic neobladder after cystectomy has been popular. In the present study, we measured the extent of metabolic acidosis in patients with ileal neobladders compared with ileal conduits and defined risk factors for development of metabolic acidosis.

Methods: We retrospectively studied 95 patients, who underwent radical cystectomy and urinary diversion to treat invasive bladder cancer from January 2001 to December 2014 at Hallym University Kangnam Sacred Heart Hospital, through investigation of acid-base balance, serum electrolyte levels and renal function one month and one year after operation.

Results: One month after the operation, metabolic acidosis was found from 18 patients (31.0%) in an ileal neobladder group and from 4 (14.8%) in an ileal conduits group. One year after the operation, the numbers became 11 (22.9%) and 2 (10.0%), respectively. However, there was not a statistical difference. The blood biochemical profiles of the two groups did not differ significantly after urinary diversion. Logistic analysis revealed that lower estimated glomerular filtration rate (eGFR) was associated with metabolic acidosis at one month (odds ratio, OR = 0.94 [0.91–0.97]; p < 0.001) and one year (OR = 0.94 [0.92–0.97]; P = 0.001) after urinary diversion. In multivariate analysis, lower eGFR is a significant risk factor for metabolic acidosis at one month.

Conclusions: Patients with ileal neobladders and conduits are at the similar risk of metabolic acidosis. A close association between renal function and development of metabolic acidosis was observed, especially stronger in an early period after operation.

Ileal Neobladder: An Important Cause of Non-Anion Gap Metabolic Acidosis

BACKGROUND

The differential diagnosis for a non-anion gap metabolic acidosis is probably less well known than the differential diagnosis for an anion gap metabolic acidosis. One etiology of a non-anion gap acidosis is the consequence of ileal neobladder urinary diversion for the treatment of bladder cancer.

CASE REPORT

We present a case of a patient with an ileal neobladder with a severe non-anion gap metabolic acidosis caused by a urinary tract infection and ureteroenterostomy. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Part of the ileal neobladder surgery includes ureteroenterostomy and predisposes patients to several clinically significant metabolic derangements, including a non-anion gap metabolic acidosis. These patients have an increased chronic acid load, bicarbonate deficit, and hypokalemia, which should be appreciated when resuscitating these patients.

Cautious use and optimal dose of morphine for relieving malignant pain in a complex patient with multiple comorbidities

Oral morphine remains the drug of choice for the management of severe pain due to cancer as per WHO ladder of analgesia. Providing adequate pain relief in palliative care settings for pain due to cancer is challenging. Options become limited in cases of associated systemic comorbidities such as renal dysfunction, hypoproteinaemia, anaemia. Patients with renal dysfunction and other comorbidities may develop drug overdose due to abnormal pharmacokinetics. Renal dysfunction affects the pharmacokinetics of morphine by altering its absorption, metabolism and clearance. Plasma albumin also influences drug availability, its plasma distribution and thus available free morphine for its clinical effect. Morphine should be used cautiously for the treatment of pain in patients with renal failure, hypoproteinaemia, hyperbilirubinaemia and anaemia. In such patients, alternate opiates like fentanyl, hydromorphone, or oxycodone may be used as these drugs are not significantly excreted by the kidneys.

Complications of Radical Cystectomy and Orthotopic Reconstruction

Radical cystectomy and orthotopic reconstruction significant morbidity and mortality despite advances in minimal invasive and robotic technology. In this review, we will discuss early and late complications, as well as describe efforts to minimize morbidity and mortality, with a focus on ileal orthotopic bladder substitute (OBS). We summarise efforts to minimize morbidity and mortality including enhanced recovery as well as early and late complications seen after radical cystectomy and OBS. Centralisation of complex cancer services in the UK has led to a fall in mortality and high volume institutions have a significantly lower rate of 30-day mortality compared to low volume institutions. Enhanced recovery pathways have resulted in shorter length of hospital stay and potentially a reduction in morbidity. Early complications of radical cystectomy occur as a direct result of the surgery itself while late complications, which can occur even after 10 years after surgery, are due to urinary diversion. OBS represents the ideal urinary diversion for patients without contraindications. However, all patients with OBS should have regular long term follow-up for oncological surveillance and to identify complications should they arise.

Evaluation and Management of the Geriatric Urologic Oncology Patient

The geriatric population presents a unique set of challenges in urologic oncology. In addition to the known natural history of disease, providers must also consider patient factors such as functional and nutritional status, comorbidities and social support when determining the treatment plan. The development of frailty measures and biomarkers to estimate surgical risk shows promise, with several assessment tools predictive of surgical complications. Decreased dependence on chronologic age is important when assessing surgical fitness, as age cutoffs prevent appropriate treatment of many elderly patients who would benefit from surgery. Within bladder, kidney and prostate cancers, continued refinement of surgical techniques offers a broader array of options for the geriatric patient than previously available.

Human urinary bladder regeneration through tissue engineering - an analysis of 131 clinical cases

Replacement of urinary bladder tissue with functional equivalents remains one of the most challenging problems of reconstructive urology over the last several decades. The gold standard treatment for urinary diversion after radical cystectomy is the ileal conduit or neobladder; however, this technique is associated with numerous complications including electrolyte imbalances, mucus production, and the potential for malignant transformation. Tissue engineering techniques provide the impetus to construct functional bladder substitutes de novo. Within this review, we have thoroughly perused the literature utilizing PubMed in order to identify clinical studies involving bladder reconstruction utilizing tissue engineering methodologies. The idea of urinary bladder regeneration through tissue engineering dates back to the 1950s. Many natural and synthetic biomaterials such as plastic mold, gelatin sponge, Japanese paper, preserved dog bladder, lyophilized human dura, bovine pericardium, small intestinal submucosa, bladder acellular matrix, or composite of collagen and polyglycolic acid were used for urinary bladder regeneration with a wide range of outcomes. Recent progress in the tissue engineering field suggest that in vitro engineered bladder wall substitutes may have expanded clinical applicability in near future but preclinical investigations on large animal models with defective bladders are necessary to optimize the methods of bladder reconstruction by tissue engineering in humans.

Metabolic complications of urinary intestinal diversion

Patients with a urinary bladder malignancy or severe anatomical/functional bladder abnormalities may be candidates for urinary diversion at the time of cystectomy. Most urinary diversions are constructed from intestinal segments. Urological surgeons who perform urinary diversion surgery should be aware of the physiological and metabolic changes that can occur when intestinal segments are in direct contact with urine. The complications associated with urinary diversion are both acute and chronic. The most important factor associated with the development of metabolic complications following urinary diversion is the length of time that the urine is in contact with the bowel and the type of bowel segment used for urinary diversion. In this review, we describe the metabolic complications associated with urinary diversion, their characteristic clinical presentation, follow-up, and specific treatment.