Ureteroscopic evaluation in renal transplant recipients

Kidney stones in renal transplant recipients: A systematic review

INTRODUCTION

Lithiasis in renal graft recipients might be a dangerous condition with a potential risk of organ function impairment.

EVIDENCE ACQUISITION

A systematic literature search was conducted through February 2023. The primary objective was to assess the incidence of lithiasis in kidney transplant (KT) recipients. The secondary objective was to assess the timing of stone formation, localization and composition of stones, possible treatment options, and the incidence of graft loss.

EVIDENCE SYNTHESIS

A total of 41 non-randomized studies comprising 699 patients met our inclusion criteria. The age at lithiasis diagnosis ranged between 29-53 years. Incidence of urolithiasis ranged from 0.1-6.3%, usually diagnosed after 12 months from KT. Most of the stones were diagnosed in the calyces or in the pelvis. Calcium oxalate composition was the most frequent. Different treatment strategies were considered, namely active surveillance, ureteroscopy, percutaneous/combined approach, or open surgery. 15.73% of patients were submitted to extracorporeal shock wave lithotripsy (ESWL), while 26.75% underwent endoscopic lithotripsy or stone extraction. 18.03% of patients underwent percutaneous nephrolithotomy whilst 3.14% to a combined approach. Surgical lithotomy was performed in 5.01% of the cases. Global stone-free rate was around 80%.

CONCLUSIONS

Lithiasis in kidney transplant is a rare condition usually diagnosed after one year after surgery and mostly located in the calyces and renal pelvis, more frequently of calcium oxalate composition. Each of the active treatments is associated with good results in terms of stone-free rate, thus the surgical technique should be chosen according to the patient's characteristics and surgeon preferences.

Flexible Ureteroscopy as the New Standard for the Management of Renal Transplant Urolithiasis <15 mm: A Single-Center Experience

Objectives: To determine the safety and efficacy of flexible ureteroscopy in the treatment of transplant urolithiasis. Materials and Methods: We reviewed a single-center series of 2652 patients who underwent surgical treatment for nephrolithiasis at our institution from 2009 to the present day to identify all patients undergoing ureteroscopy for treatment of transplant lithiasis. Results: We identified 18 patients who underwent ureteroscopy for treatment of urolithiasis within the transplanted kidney or ureter. The majority of the procedures were performed using a retrograde approach with flexible ureteroscopy, with one patient undergoing antegrade ureteroscopy and two patients requiring semirigid ureteroscopy. Holmium:yttrium-aluminum-garnet laser lithotripsy was utilized in all but one case, which was performed using basket extraction. There were no intraoperative complications reported. Four patients had small stone fragments on postoperative imaging, three of which were observed. One patient required repeat ureteroscopy for persistent distal ureteral stone. Conclusion: Retrograde ureteroscopy is a feasible, safe, and effective intervention for the treatment of transplant lithiasis. Minimal intraoperative or postoperative complications were reported, and only one patient required additional intervention for residual stone burden.

Incidence of kidney stones in kidney transplant recipients: A systematic review and meta-analysis

AIM

To evaluate the incidence and characteristics of kidney stones in kidney transplant recipients.

METHODS

A literature search was performed using MEDLINE, EMBASE, and Cochrane Database of Systematic Reviews from the inception of the databases through March 2016. Studies assessing the incidence of kidney stones in kidney transplant recipients were included. We applied a random-effects model to estimate the incidence of kidney stones.

RESULTS

Twenty one studies with 64416 kidney transplant patients were included in the analyses to assess the incidence of kidney stones after kidney transplantation. The estimated incidence of kidney stones was 1.0% (95%CI: 0.6%-1.4%). The mean duration to diagnosis of kidney stones after kidney transplantation was 28 ± 22 mo. The mean age of patients with kidney stones was 42 ± 7 years. Within reported studies, approximately 50% of kidney transplant recipients with kidney stones were males. 67% of kidney stones were calcium-based stones (30% mixed CaOx/CaP, 27%CaOx and 10%CaP), followed by struvite stones (20%) and uric acid stones (13%).

CONCLUSION

The estimated incidence of kidney stones in patients after kidney transplantation is 1.0%. Although calcium based stones are the most common kidney stones after transplantation, struvite stones (also known as “infection stones”) are not uncommon in kidney transplant recipients. These findings may impact the prevention and clinical management of kidney stones after kidney transplantation.

[Urinary lithiasis in renal transplant recipient]

OBJECTIVES

To report epidemiology and characteristics of urinary lithiasis and its management in kidney allograft at the time of organ procurement or after kidney transplantation.

MATERIAL AND METHODS

An exhaustive systematic review of the scientific literature was performed in the Medline database (http://www.ncbi.nlm.nih.gov) and Embase (http://www.embase.com) using different associations of the following keywords (MESH): urinary lithiasis, stone, kidney transplantation. Publications obtained were selected based on methodology, language, date of publication (last 10 years) and relevance. Prospective and retrospective studies, in English or French, review articles; meta-analysis and guidelines were selected and analyzed. This search found 58 articles. After reading, 37 were included in the text based on their relevance.

RESULTS

Frequency of urinary lithiasis in renal transplant recipient is similar to those observed in the general population. Generally, urinary lithiasis of the graft is asymptomatic because of renal denervation after organ procurement and transplantation. Nevertheless, this situation may be at high risk due to the immunosuppressed state of the recipient with a unique functioning kidney. Most of the time, the diagnosis is incidental during routine post-transplantation follow-up. Management of urolithiasis in renal transplant recipient is similar to that performed in general population.

CONCLUSION

Due to its potential severity in transplanted immunosuppressed patients with a sole kidney, urolithiasis requires expert urological management.

Management of stones in abnormal situations

Stones in abnormal situations present a management conundrum to the urologist. Many of these situations are relatively rare and literature is scanty on the appropriate management. We review the current literature on the management of stones in the setting of pregnancy, calyceal diverticulum, urinary diversions, pelvic kidneys, transplant kidneys, autosomal dominant polycystic kidney disease, horseshoe kidneys, and other renal anomalies. The aims of treatment are complete stone-free status. The modality of treatment should be individualized to the size and location of stone and type of abnormal situation confronted.

Ureteroscopy for transplant lithiasis

BACKGROUND AND PURPOSE

The optimal management of renal and ureteral calculi in transplanted kidneys is not well defined. Although larger (>1.5 cm) stone burdens are generally treated with percutaneous nephrolithotomy (PCNL), smaller stones may be reasonably approached with retrograde or antegrade ureteroscopy (URS). We report our multicenter experience with URS for transplant lithiasis.

PATIENTS AND METHODS

URS performed for stone disease within a transplanted kidney were retrospectively identified at three stone-referral centers between 2006 and 2011. Demographic and disease parameters were recorded, as were perioperative and postoperative details.

RESULTS

Twelve patients underwent URS for a calculus in a transplant renal unit and/or ureter. For retrograde procedures (7), access to the ureteral orifice was facilitated by the use of a Kumpe catheter; a two-wire (safety and working guidewire) technique was used. For antegrade procedures (5), the ureteroscope was passed into the kidney using a two-wire technique without tract dilation. All stones but one necessitated holmium:yttrium-aluminum-garnet laser lithotripsy with extraction of stone fragments. All patients were stone free on postoperative imaging except for one patient with a 2-mm fragment that was observed. Stone analysis included calcium oxalate (6), calcium phosphate (4), and struvite (1).

CONCLUSION

Antegrade and retrograde URS are safe and effective treatments for patients with simple stone burdens in a transplanted kidney. Although retrograde access to the ureter can be challenging, specialized techniques and modern endoscope technology facilitate this process. Antegrade URS for small stone burdens can be performed safely and effectively without tract dilation.

Renal transplant lithiasis: analysis of our series and review of the literature

BACKGROUND AND PURPOSE

Renal transplant lithiasis represents a rather uncommon complication. Even rare, it can result in significant morbidity and a devastating loss of renal function if obstruction occurs. We present our experience with graft lithiasis in our series of renal transplantations and review the literature regarding the epidemiology, pathophysiology, and current therapeutic strategies in the management of renal transplant lithiasis.

PATIENTS AND METHODS

In a retrospective analysis of a consecutive series of 1525 renal transplantations that were performed between January 1983 and March 2007, 7 patients were found to have allograft lithiasis. In five cases, the calculi were localized in the renal unit, and in two cases, in the ureter. A review in the English language was also performed of the Medline and PubMed databases using the keywords renal transplant lithiasis, donor-gifted lithiasis, and urological complications after kidney transplantation. Several retrospective studies regarding the incidence, etiology, as well as predisposing factors for graft lithiasis were reviewed. Data regarding the current therapeutic strategies for graft lithiasis were also evaluated, and outcomes were compared with the results of our series.

RESULTS

Most studies report a renal transplant lithiasis incidence of 0.4% to 1%. In our series, incidence of graft lithiasis was 0.46% (n=7). Of the seven patients, three were treated via percutaneous nephrolithotripsy (PCNL); in three patients, shockwave lithotripsy (SWL) was performed; and in a single case, spontaneous passage of a urinary calculus was observed. All patients are currently stone free but still remain under close urologic surveillance.

CONCLUSION

Renal transplant lithiasis requires vigilance, a high index of suspicion, prompt recognition, and management. Treatment protocols should mimic those for solitary kidneys. Minimally invasive techniques are available to remove graft calculi. Long-term follow-up is essential to determine the outcome, as well as to prevent recurrence.

Ureteroscopic management of urological complications after renal transplantation

OBJECTIVE

To determine the feasibility, safety and efficacy of diagnostic and therapeutic ureteroscopy in renal allograft ureters.

MATERIAL AND METHODS

We reviewed 1560 consecutive renal allografts performed between June 1989 and February 2002. A total of 28 patients (1.8%) had indications for an endoscopic procedure on the allograft ureter, as follows: obstructive ureteral calculi with a history of failed extracorporeal shock-wave lithotripsy, n=6; suspected ureteral stricture, n=3; upwardly migrated ureteral stents, n=9; and ureteral stricture at the ureteroneocystostomy site, n=10. Ureters were anastomosed to the bladder using the Leadbetter-Politano and Lich-Gregoire methods in six and 22 cases, respectively. Ureteroscopies were performed with a semi-rigid 9.8 F Wolf ureteroscope.

RESULTS

Identification of the ureteral orifice and insertion of a guide-wire into it was successful in 19 cases (68%). If we exclude the 10 patients with ureteral stricture, ureteroscopy was successful in 13/18 cases (72%). Four ureteral calculi (67%) were removed with the ureteroscope. Seven out of nine migrated stents (78%) were retrieved. Four patients with ureteral stricture at the ureteroneocystostomy site (40%) underwent successful ureteral dilatation and double-J ureteral catheters were also inserted. Diagnostic ureteroscopy was successful in all cases. Two complications (one urinary leakage and one symptomatic urinary tract infection) occurred and were managed conservatively.

CONCLUSIONS

Ureteral endoscopy is a safe and effective method for the management of urological complications after renal transplantation. This procedure can be considered the first choice, in preference to percutaneous and antegrade modalities.

Percutaneous nephrolithotomy success in the transplant kidney

PURPOSE

Treatment for symptomatic calculi in the transplanted kidney can be problematic. Percutaneous nephrolithotomy has routinely been used but concerns exist about potential injury to adjacent organs using a percutaneous access technique. We report our experience with percutaneous nephrolithotomy in the transplant kidney.

MATERIALS AND METHODS

A retrospective chart review from 1988 to the present was performed of all cases of a renal transplant and subsequent renal calculi treated with percutaneous nephrolithotomy.

RESULTS

We identified 13 patients with a renal transplant who underwent percutaneous nephrolithotomy. Presenting symptoms included renal failure in 46.1% of cases, hematuria in 23.1%, urinary tract infection/pyelonephritis in 23.1%, pain in 15.4%, fever in 7.7% and hydronephrosis in 7.7%. Average calculus size was 1.36 cm (range 0.2 to partial staghorn). A single access tract was used in 12 cases and 2 access tracts were used in 1. Ultrasonic lithotripsy was performed in 10 cases, basket extraction was performed in 3 and the 2 techniques were performed in 1. No intraoperative complications occurred. Nephrostogram 24 hours after the procedure demonstrated no residual fragments in 10 patients (76.9%). Repeat endoscopy was required in 3 patients to achieve subsequent stone-free status. Postoperative complications developed in 3 patients, including sepsis, gastrointestinal bleeding and herpes esophagitis, respectively. Mean followup was 5.3 years (range 0.6 to 9). The single stone recurrence was treated with shock wave lithotripsy. Mean creatinine was stable at 2.0 mg/dl (range 0.9 to 3.9) preoperatively to 1.7 mg/dl (range 0.9 to 2.6) at the last visit (p = 0.311).

CONCLUSIONS

Percutaneous nephrolithotomy is safe and effective in the transplanted kidney. Minimal postoperative complications were noted and stone-free status was achieved in all cases. At long-term followup there were few stone recurrences with stable graft function after the procedure.

Treatment Selection and Outcomes: Renal Calculi

This article summarizes the history of how renal stones have been treated over the centuries and reviews current treatments and outcomes for renal stones. The authors provide an algorithm based on available outcome data for shock wave lithotripsy, ureteroscopy, and percutaneous nephrolithotomy.

Treatment of Stones Associated with Complex or Anomalous Renal Anatomy

This article reviews the most common renal anomalies and the management of patients with calculus disease in anomalous kidneys. The emphasis is on minimally invasive techniques to achieve a stone-free status with minimal morbidity.

Endoscopic Management of Ureteral Complications Following Renal Transplantation

Management of ureteral complications after kidney transplantation can be done with a surgical, percutaneous, or endoscopic approach. The aim of this study was to determine the success rate of the endoscopic retrograde approach for the management of these complications following renal transplantation. We reviewed the records of 25 patients who underwent endoscopic management of ureteral complications after renal transplant between 1995 and 2005. Variables examined included timing of event following transplant, type of ureteral complication, equipment implemented in the procedure, operating time, success in stent placement, and complications. Initial approach was via rigid cystoscopy followed by flexible cystoscopy if needed. Initial attempts to intubate the ureteral orifice were by a flexible-tipped guide wire, and occasionally an angiocatheter guide was used for ultimate wire placement. Stents were positioned with fluoroscopic and direct visual guidance. Of 25 patients evaluated, five had a ureteral anastomotic leak with a mean time of presentation of 16.8 days. The remaining 20 patients suffered from ureteral obstruction revealed by hydronephrosis on a renal ultrasound prompted by a rising creatinine. Mean time of onset was 48 months. Although each was initially approached with rigid cystoscopy, 12 were converted to flexible cystoscopy for easier access to the ureteral orifice. Twenty of the 25 patients had successful stent placement with three failures in the ureteral obstruction group and two failures in the leakage group. Average operative time was 42 minutes. No intraoperative complications were experienced. Resolution of hydronephrosis in those with preoperative obstruction was noted and all stented urinary leaks resolved.

Stone-bearing live-donor kidneys for transplantation

OBJECTIVE

To evaluate potential donor kidneys with asymptomatic calculi detected during screening, and the management of the calculus before, during and after transplantation, as with fewer live donors, marginal kidneys and donors are a significant subgroup in renal transplantation.

PATIENTS AND METHODS

Five live-related donors, with one incidentally detected calculus during their routine evaluation, were accepted for transplantation. Of these, three were detected only on spiral computed angiography. There was no biochemical evidence of a metabolic abnormality or history of stone disease. One donor had elective lithotripsy and another nephrolithotomy under ultrasonographic control immediately after perfusion. The others were transplanted with the calculus in situ. Ureteric reimplantation was by the Leadbetter-Politano technique over a JJ stent.

RESULTS

One recipient patient passed the calculus within 4 h of stent removal. The follow-up ultrasonogram at 3 months showed a stone in only one recipient. In the others, the calculus could not be seen after stent removal. The maximum follow-up was 2 years and graft function has remained normal in all.

CONCLUSIONS

Voluntary kidney donors with one calculus incidentally detected on routine evaluation form a unique group and can be accepted for transplantation in selected cases. Careful follow-up of the donor and recipient is essential, with early intervention if necessary.

Urolithiasis in allograft kidneys

OBJECTIVES

Allograft stones are an uncommon clinical problem and management is mainly based on anecdotal experience, rather than analysis of larger series.

METHODS

In an 8-year period, 19 patients were treated for 19 renal and 3 ureteral stones. In 9 patients, stones were transplanted and 10 formed de novo stones within a mean of 28 months (range 13 to 48) after transplantation. In 4 patients, stones were removed during transplantation. Seven patients were treated with extracorporeal shock wave lithotripsy (ESWL), 3 patients had stones removed percutaneously, 1 by antegrade ureteroscopy, and 1 at the time of ureteral reimplantation. Three patients passed stones spontaneously.

RESULTS

In 3 of 4 patients with stones detected before transplantation, the procedure was completed successfully after endoscopic stone removal. Three of 5 patients with transplanted stones required emergency nephrostomy; 1 patient had permanent renal impairment. Three (42.9%) of 7 patients treated with ESWL needed transient nephrostomy; ultimately, all became stone free within a mean 15 days (range 10 to 40). Endoscopic stone removal always resulted in complete clearance without renal impairment. All patients were stone free during a follow-up of 29 months (range 13 to 48).

CONCLUSIONS

Nine (47%) of 19 stones were actually transplanted. Therefore, intraoperative screening by ultrasonography with subsequent endoscopic removal is advisable. Small stones (4 mm or less) may be closely followed up, because they can pass spontaneously. ESWL is the treatment of choice for caliceal stones sized 5 to 15 mm. However, for stones greater than 15 mm or for ureteral stones, antegrade endoscopic procedures seem to be more favorable.

[Urologic complications in renal transplantation. Study of 250 cases]

OBJECTIVE

The aim of this study is value the incidence of urological complications (fistulae and estenosis) in our serie of renal transplant, to analyze the variables that can influence in their appearance and the treatments used. Likewise, to value the follow-up of theses patients and the survival of the renal graft and of the patient.

MATERIAL AND METHODS

250 renal transplants are carried out between july of 1985 and october of 1998. The relationship among the variables you makes by means of the test chi 2 of Pearson and the test of Fisher; the contrasts of stockings with the t of Student; the survival of the organ and of the patient, by means of the analysis of curved of survival according to the method of Kaplan and Meier; and the comparison among curved of survival was carried out with the test of Cloth and Cox.

RESULTS

Of the 250 transplants, 46 patients suffered for complications, 29 urinary fistulae (11.6%) and 21 estenosis (8.4%). The most frequent localization in both complications was the union uretero-vesical. The presence of urinary fistulae didn't influence negatively in a significant way nor over the survival of the implant (p < 0.211), neither over the patient's survival. The estenosis appearance was related in a significant way with the donor's age (p < 0.02). The estenosis presence was not related in a significant way neither with the survival of the implant neither with that of the receiver.

CONCLUSIONS

The incidence of urological complications was of 18.4% (11.6% estenosis and 8.4% fistulae). The most frequent localization was the union uretero-vesical. The presence of estenosis correlated with the increase of the age of the donors. The technique of reimplante ureteral didn't influence in the results in a significant way. We don't find any relationship between the appearance of urological complications and the patient's survival.

Renal transplant complications. Minimally invasive management

Advancements in endourology, laparoscopic urology, and interventional radiology continue to influence the contemporary management of renal transplant complications. The successful implementation of these minimally invasive therapies significantly relies on careful patient selection; not all renal transplantation complications are suitable or amenable for this form of management--true for transplant ureteral complications and less so for other potential complications. With such a strategy, renal transplant complications can be managed efficiently and effectively with these minimally invasive modalities to minimize further recipient morbidity while also minimizing potential risk to the recipient and for the renal allograft.

O'Brien peel-away sheath: an alternative for allograft percutaneous nephroscopy

Percutaneous access and antegrade intervention remains the gold standard in the management of renal and ureteral complications in the renal transplant recipient. Current techniques with large nephrostomy sheaths and instrumentation carry significant morbidity in this patient population. We present our experience with a modification of the standard nephroscopic approach using a smaller (16F) O'Brien suprapubic peel-away introducer and sheath to access the allograft renal pelvis and allow manipulation with a smaller-caliber endoscope, with the purpose of attaining similar treatment outcomes with less morbidity in this subset of patients. Fourteen renal transplant patients with indications for antegrade management of renal or proximal ureteral complications had successful endoscopic intervention through the smaller sheaths without suffering any intraoperative or postoperative complications at a mean follow-up of 22 months (range 8-37 months). The mean operative time was 140 minutes (33-190 minutes), which is not significantly different from our operative time using standard instrumentation.