Minimally invasive treatment of renal transplant nephrolithiasis

Comprehensive Approaches to Urolithiasis in Renal Transplants: A Narrative Review

This review addresses the management of urolithiasis in renal transplant recipients, a notably vulnerable group due to the unique anatomical and physiological alterations of the transplanted organ. The prevalence of nephrolithiasis in these patients varies between 0.1% and 6.3%, with a significant impact on graft longevity and function. Surgical access complications due to the renal graft's position on the iliac vessels and the variety of urinary anastomoses complicate the treatment approaches. This study evaluates the effectiveness and outcomes of percutaneous nephrolithotomy (PCNL) and ureteroscopy (URS), two primary minimally invasive strategies for managing graft stones. Through a narrative review using the PubMed and EMBASE databases, it was found that PCNL offers high stone-free rates especially beneficial for large stones, whereas URS provides a less invasive option with a lower risk of complications for small stones. Both techniques require tailored approaches based on stone composition-mostly calcium oxalate-and specific patient anatomical factors. This review underscores the importance of early diagnosis, appropriate treatment selection, and continuous post-treatment monitoring to mitigate risks and promote long-term renal function in transplant recipients.

Management of deceased and living kidney donor with lithiasis: a multicenter retrospective study on behalf of the renal transplant group of the Spanish urological association

BACKGROUND

To maximize the availability of suitable grafts and ensure effective management, several reports have demonstrated successful outcomes when using kidney grafts with urolithiasis. This multicenter study reports on the management and long-term outcomes of kidney transplantation using renal grafts with lithiasis.

METHODS

Retrospective data from three Spanish hospitals were analyzed for kidney transplants involving grafts with nephrolithiasis performed between December 2009 and August 2023. The study included adult patients, excluding those with incomplete records. It evaluated stone characteristics, complications, and outcomes in recipients and in living kidney donors.

RESULTS

Out of 38 analyzed kidney transplants, 57.9% were cadaveric and 42.1% were from living kidney donors. Most diagnoses were incidental during donor evaluation, with an average stone size of 7.06 mm. After follow-up (median 26 months), all recipients but one had functioning grafts, and there were no stone recurrences in both recipients and living kidney donors. Conservative management was adopted in 28 cases, while 10 cases required ex-vivo flexible ureterorenoscopy for stone removal. Following conservative management, 5 patients needed additional treatments for stone-related events.

CONCLUSIONS

Kidneys with lithiasis can be considered for transplantation in selected cases, resulting in good functional outcomes with no stone recurrence in recipients or living donors.

Percutaneous nephrolithotomy for adult renal transplant de novo graft lithiasis: a single center analysis and systematic review of the literature

INTRODUCTION/OBJECTIVE

Graft stones in renal transplant recipients pose a unique challenge, finding effective interventions to ensure optimal graft function and patient well-being. Various methods of stone clearance have been described for graft stones, including percutaneous nephrolithotomy (PCNL). While PCNL is a promising approach for managing graft stones, specific outcomes and associated characteristics for this approach have not been comprehensively evaluated before. This study aims to evaluate the safety and efficacy of the use of PCNL as the primary intervention of graft stones by assessing stone-free rates (SFR), treatment impact on graft function, and perioperative complications.

METHODS

A retrospective clinical audit was performed for all transplants performed in a single center from 2007 to 2022, which included all graft lithiasis patients who were treated with PCNL. Both perioperative parameters and post-operative outcomes were collected. In addition, a systematic review including articles from MEDLINE, Embase, Web of Science yielded 18 full-text articles published between 1/1/2000 and 15/11/2023. The results pertaining to patients who underwent PCNLs for graft stones were cross-referenced and thoroughly evaluated. The review encompassed a comprehensive analysis of clinical data, postoperative outcomes, and procedural details. The protocol for the systematic review was prospectively registered on PROSPERO (CRD42023486825).

RESULTS

In our center, 6 graft lithiasis patients were treated with PCNL. The initial SFR was 83.3%. SFR at 3 months and 1 year were both 100.0%. SFR at 3 years was 66.7%. Other centers reported initial SFR of 82.6-100.0% (interquartile range). SFR at 3 months, 1 year, 3 years was not well reported across the included studies. Incidence of graft lithiasis ranged from 0.44%-2.41%. Most common presentations at diagnosis were oliguria/anuria/acute kidney injury and asymptomatic. Reported complications included blood loss, transient hematuria, high urine output, sepsis, and damage to surrounding structures. The most commonly reported metabolic abnormalities in transplant lithiasis patients included hyperuricemia and hyperparathyroidism.

CONCLUSION

PCNL is a practical and efficient choice for addressing graft lithiasis, demonstrating excellent stone clearance and minimal perioperative complications. These findings show the importance of PCNL as a primary intervention in this complex patient population.

Percutaneous Nephrolithotomy for De Novo Urolithiasis After Kidney Transplantation: A Systematic Review of the Literature

Introduction and Objective: Renal transplantation is the treatment for end-stage renal disease that offers better quality of life and survival. Among the possible complications that might affect allografts, urolithiasis might have severe consequences, causing acute kidney injury (AKI) or septic events in immunocompromised patients. Allograft stones might be treated with percutaneous nephrolithotomy (PCNL). The aim of this Cochrane style review was to assess the safety and efficacy of PCNL in patients with renal transplant. Methods: A comprehensive search in the literature was performed including articles between July 1982 and June 2023, with only English original articles selected for this review. Results: The final review encompassed nine articles (108 patients). The mean age was 46.4 ± 8.7 years, with a male:female ratio of 54:44. The average time from transplantation to urolithiasis onset was 47.54 ± 23.9 months. Predominant symptoms upon presentation were AKI (32.3%), followed by urinary tract infection and fever (24.2%), and oliguria (12.9%). The mean stone size was 20.1 ± 7.3 mm, with stones located in the calices or pelvis (41%), ureteropelvic junction (23.1%), or proximal ureter (28.2%). PCNL (22F-30F) was more frequently performed than mini-PCNLs (16F-20F) (52.4% vs 47.6%). Puncture was guided by ultrasound (42.9%), fluoroscopy (14.3%), or both (42.9%). The stone-free rate (SFR) and complication rates were 92.95% (range: 77%-100%) and 5.5%, respectively, with only one major complication reported. Postoperatively, a ureteral stent and nephrostomy were commonly placed in 47%, with four patients needing a second look PCNL. During an average follow-up of 32.5 months, the recurrence rate was 3.7% (4/108), and the mean creatinine level was 1.37 ± 0.28 mg/dL. Conclusions: PCNL remains a safe and effective option in de novo allograft urolithiasis, allowing to treat large stones in one-step surgery. A good SFR is achieved with a low risk of minor complications. These patients should be treated in an endourology center in conjunction with the renal or transplant team.

URS for de-novo urolithiasis after kidney transplantation: a systematic review of the literature

INTRODUCTION

There is a gap in the available literature and guidelines concerning the optimal approach for treating allograft stones, which currently include external shockwave lithotripsy, ureteroscopy and laser lithotripsy, or percutaneous nephrolithotomy. The objective of this systematic review was to evaluate the safety and effectiveness of URS as a treatment option for patients in this scenario.

EVIDENCE ACQUISITION

A comprehensive search of the literature was conducted until August 2023. Only original articles written in English were considered for inclusion. This review has been registered in PROSPERO (registration number CRD42023451154).

EVIDENCE SYNTHESIS

Eleven articles were included (122 patients). The mean age was 46.9±9.5 years, with a male-to-female ratio of 62:49. The preferred ureteral reimplantation technique was the Lich-Gregoire. The mean onset time was 48.24 months. Acute kidney injury, urinary tract infections and fever were the most frequent clinical presentations (18.3% each), followed by hematuria (10%). The mean stone size measured 9.84 mm (±2.42 mm). Flexible URS was preferred over semirigid URS. The stone-free rate stood at 83.35%, while the overall complication rate was 13.93%, with six (4.9%) major complications reported. Stones were mainly composed of calcium oxalate (42.6%) or uric acid (14.8%). Over an average follow-up period of 30.2 months, the recurrence rate was 2.46%. No significant changes in renal function or allograft loss were reported.

CONCLUSIONS

URS remains an efficient choice for addressing de-novo allograft urolithiasis, offering the advantage of treating urinary stones with a good SFR and a low incidence of complications. Procedures should be performed in an Endourology referral center.

Management of de novo nephrolithiasis after kidney transplantation: a comprehensive review from the European Renal Association CKD-MBD working group

The lifetime incidence of kidney stones is 6%-12% in the general population. Nephrolithiasis is a known cause of acute and chronic kidney injury, mediated via obstructive uropathy or crystal-induced nephropathy, and several modifiable and non-modifiable genetic and lifestyle causes have been described. Evidence for epidemiology and management of nephrolithiasis after kidney transplantation is limited by a low number of publications, small study sizes and short observational periods. Denervation of the kidney and ureter graft greatly reduces symptomatology of kidney stones in transplant recipients, which may contribute to a considerable underdiagnosis. Thus, reported prevalence rates of 1%-2% after kidney transplantation and the lack of adverse effects on allograft function and survival should be interpreted with caution. In this narrative review we summarize current state-of-the-art knowledge regarding epidemiology, clinical presentation, diagnosis, prevention and therapy of nephrolithiasis after kidney transplantation, including management of asymptomatic stone disease in kidney donors. Our aim is to strengthen clinical nephrologists who treat kidney transplant recipients in informed decision-making regarding management of kidney stones. Available evidence, supporting both surgical and medical treatment and prevention of kidney stones, is presented and critically discussed. The specific anatomy of the transplanted kidney and urinary tract requires deviation from established interventional approaches for nephrolithiasis in native kidneys. Also, pharmacological and lifestyle changes may need adaptation to the specific situation of kidney transplant recipients. Finally, we point out current knowledge gaps and the need for additional evidence from future studies.

Urolithiasis in Kidney Transplant Patients: A Multicenter KSER Research Series

Background and Objectives: Urolithiasis occurrence is uncommon in kidney transplantation patients, though it has serious implications, including acute kidney injury in the transplanted kidney. This study investigates the leading causes of urolithiasis in kidney transplantation patients, the diagnostic process, and the outcomes of multimodal management. Materials and Methods: Data collection spanned from January 1997 to December 2021, involving kidney transplantation patients with urolithiasis from the database of the Korean Society of Endourology and Robotics (KSER) research committee. Analysis encompassed factors triggering urolithiasis, the diagnostic process, stone attributes, treatment methods, and outcomes. Results: Our analysis included 58 kidney transplantation patients with urolithiasis from eight medical centers. Of these patients, 37 were male and 4 had previous urolithiasis diagnoses. The mean age was 59.09 ± 10.70 years, with a mean duration from kidney transplantation to diagnosis of 76.26 ± 183.14 months. The most frequent method of stone detection was through asymptomatic routine check-ups (54.7%). Among the 58 patients, 51 underwent stone treatment. Notably, 95.3% of patients with ureter stones received treatment, a significantly higher rate than the 66.7% of patients with renal stones (p = 0.010). Success rates showed no significant differences between renal (70%) and ureter stone (78.0%) groups (p = 0.881). Conclusions: Urolithiasis in transplanted kidneys constitutes an acute condition requiring emergency intervention. Endo-urological interventions are effective for kidney transplantation patients with urolithiasis. To ensure prevention and early detection, diligent follow-up and routine imaging tests are necessary.

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.

The Saudi urological association guidelines on urolithiasis

Aims

The Saudi Urolithiasis Guidelines are a set of recommendations for diagnosing, evaluating, and treating urolithiasis in the Saudi population. These guidelines are based on the latest evidence and expert consensus to improve patient outcomes and optimize care delivery. They cover the various aspects of urolithiasis, including risk factors, diagnosis, medical and surgical treatments, and prevention strategies. By following these guidelines, health-care professionals can improve care quality for individuals with urolithiasis in Saudi Arabia.

Panel

The Saudi Urolithiasis Guidelines Panel consists of urologists specialized in endourology with expertise in urolithiasis and consultation with a guideline methodologist. All panelists involved in this document have submitted statements disclosing any potential conflicts of interest.

Methods

The Saudi Guidelines on Urolithiasis were developed by relying primarily on established international guidelines to adopt or adapt the most appropriate guidance for the Saudi context. When necessary, the panel modified the phrasing of recommendations from different sources to ensure consistency within the document. To address areas less well covered in existing guidelines, the panel conducted a directed literature search for high quality evidence published in English, including meta analyses, randomized controlled trials, and prospective nonrandomized comparative studies. The panel also searched for locally relevant studies containing information unique to the Saudi Arabian population. The recommendations are formulated with a direction and strength of recommendation based on GRADE terminology and interpretation while relying on existing summaries of evidence from the existing guidelines.

Shockwave Lithotripsy for De-Novo Urolithiasis after Kidney Transplantation: A Systematic Review of the Literature

BACKGROUND

Allograft urolithiasis is an uncommon, challenging, and potentially dangerous clinical problem. Treatment of allograft stones includes external shockwave lithotripsy (SWL), flexible ureteroscopy and lasertripsy (fURSL), or percutaneous nephrolithotomy (PCNL). A gap in the literature and guidelines exists regarding the treatment of patients in this setting. The aim of this systematic review was to collect preoperative and treatment characteristics and evaluate the outcomes of post-transplant SWL for stone disease.

METHODS

A systematic search in the literature was performed, including articles up to March 2023. Only original English articles were selected.

RESULTS

Eight articles (81 patients) were included in the review. Patients were mainly male, with a mean age of 41.9 years (±7.07). The mean stone size was 13.18 mm (±2.28 mm). Stones were predominantly located in the kidney (n = 18, 62%). The overall stone-free rate and complication rates were 81% (range: 50-100%) and 17.2% (14/81), respectively, with only one major complication reported. A pre-operative drainage was placed in eleven (13.5%) patients. Five patients (6.71%) required a second treatment for residual fragments.

CONCLUSIONS

SWL is a safe and effective option to treat de novo stones after transplantation. Larger studies are needed to better address allograft urolithiasis management.

Living donor-gifted allograft lithiasis: surgical experience after bench surgery stone removal and follow-up

This study presents the surgical experience and long-term outcomes of living donor kidney transplantations involving asymptomatic kidney stones, using ex vivo flexible ureterorenoscopy (f-URS) during bench surgery for stone removal. Out of 1743 living kidney donors assessed between January 2012 and October 2022, 18 (1%) were diagnosed with urolithiasis. Among them, 12 donors were rejected, and 6 were accepted for kidney donation. Stone removal was successfully performed using f-URS during bench surgery, with no immediate complications or acute rejections observed. The study analyzed six living kidney transplants, of which 4 (67%) donors and three recipients were female, and 4 (67%) donors were blood-related to the recipient. The median age for donors and recipients was 57.5 and 51.5 years, respectively. The stones, primarily located in the lower calyx, had a median size of 6 mm. The median cold ischemia time during surgery was 41.6 min, and ex vivo f-URS ensured complete stone removal in all cases. After a median follow-up of 120 months, the remaining grafts were functioning well, and no urinary stone recurrence was observed in either the recipients or living donors. The findings suggest that bench f-URS is a safe approach for managing urinary stones in kidney grafts, providing good functional outcomes without stone recurrence in selected cases.

Outcomes of live renal donors with a history of nephrolithiasis; A systematic review

The clinical outcomes of kidney donors with a prior history of nephrolithiasis are poorly defined. We conducted a systematic review assessing the post-donation clinical outcomes of kidney donors with a history of nephrolithiasis. Electronic databases (Ovid and Embase) were searched between 1960 and 2021 using key terms and Medical Subject Headings (MeSH) - nephrolithiasis, renal stones, renal transplantation and renal graft. Articles included conference proceedings and journal articles and were not excluded based on patient numbers. Primary outcome was donor stone-related event. Secondary outcomes were renal function upon follow-up or post-operative nephrectomy complications. In summary, 340 articles were identified through database search. We identified 14 studies (16 cohorts) comprising 432 live donors followed up for a median of 26 months post live kidney donation. Six donors donated the stone-free kidney whilst 23 live donors had bilateral stones. Mean stone size was 4.2 ± 1.4 mm (1-16) with average follow up duration of 21.1 months (1-149). Twelve studies provided primary outcome (n = 138 patients) and eight (n = 348) for secondary outcomes. One donor had a stone-related event upon follow up. A total of 195 patients had eGFR <60 upon follow up. However, they were not significantly different when compared to renal function of live donors that didn't have pre-donation nephrolithiasis. Many of the studies couldn't provide long term follow up, coupled with limited data regarding the nature of the pre-donation stone disease. In conclusion, this systematic review shows that we have very limited information upon which to base recommendation regarding pre-donation risk of post-donation complications. Longer term follow up is required and lifelong follow up with live donor registries will aid further understanding.

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.

[Urinary stones in renal transplant recipients and donors: The French guidelines from CTAFU]

OBJECTIVE

To define guidelines for the management of kidney stones in kidney transplant (KTx) donor or recipients.

METHOD

Following a systematic approach, a review of the literature (Medline) was conducted by the CTAFU to report kidney stone epidemiology, diagnosis and management in KTx donors and recipients with the corresponding level of evidence.

RESULTS

Prevalence of kidney stones in deceased donor is unknown but reaches 9.3% in living donors in industrialized countries. Except in Maastrich 2 donors, diagnosis is done on systematic pre-donation CT scan according to standard french procedure. No prospective study has compared therapeutic strategies available for the management of kidney stones in KTx donor: ureteroscopy or an extra corporeal lithotripsy in case of living donor prior to donation, ex vivo approach (pyelotomy or ureteroscopy), ureterocopy in the KTx recipient or surveillance. De novo kidney stones result from a lithogenesis process to be identified and treated in order to avoid recurrences. The context of solitary functional kidney renders the prevention of recurrence of great importance. Diagnosis is suspected when identification of a renal graft dysfunction, hematuria or urinary tract infection with renal pelvis dilatation. Stone size and location are determined by computed tomography. There are no prospective, controlled studies on kidney stone management in the KTx. The therapeutic strategies are similar to standard management in general population.

CONCLUSION

These French recommendations should contribute to improve kidney stones management in KTx donor and recipients.

[Urolithiasis of the kidney transplanted patient in south Tunisia: A 17-year experience]

INTRODUCTION

Urolithiasis in a kidney transplanted patient is an uncommon but complex urological complication. Its potential severity comes from its occurrence on a solitary kidney and on a field of immunosuppression. The aim of our study is to assess the incidence, characteristics and course of urolithiasis in our series.

METHODS

A retrospective study was performed. We included kidney transplanted patients between November 2002 and November 2019 and presenting lithiasis during their follow-up. Clinical, biological and radiological data were collected as well as lithiasis disease related data. The management of and patient's evolution were also specified.

RESULTS

Seven of 416 kidney transplanted patients developed lithiasis during their follow-up with an incidence of 1.6 %. The mean age at lithiasis diagnosis was 36.5 years [24-55 years], the sex ratio was 1.3. They developed stones after mean follow-up of 67 months [4-168 months]. The stones' size varied from 2 to 18mm. Treatment was alkalisation in 3 cases, extracorporeal lithotripsy in 2 cases, a double J stent in 3 cases and pyelolithotomy in 2 cases. Four patients had multiple treatments. Three patients had 1 residual stone during evolution (7mm average diameter), 1 microlithiasis, 1 lost to follow-up after treatment and only 2 (out of 7) were "stone free". Furthermore, lithiasis didn't damage the graft survival after a median follow-up of 62 months post-treatment.

CONCLUSION

Urolithiasis in the kidney transplanted patient requires an adapted multidisciplinary management. Its skill is a challenge for both the nephrologist and urologist.

Treatment of recurrent renal transplant lithiasis: analysis of our experience and review of the relevant literature

BACKGROUND

Renal transplant lithiasis is a rather unusual disease, and the recurrence of lithiasis presents a challenging situation.

METHODS

We retrospectively analyzed the medical history of one patient who suffered renal transplant lithiasis twice, reviewed the relevant literature, and summarized the characteristics of this disease.

RESULTS

We retrieved 29 relevant studies with an incidence of 0.34 to 3.26% for renal transplant lithiasis. The summarized incidence was 0.52%, and the recurrence rate was 0.082%. The mean interval after transplantation was 33.43 ± 56.70 mo. Most of the patients (28.90%) were asymptomatic. The management included percutaneous nephrolithotripsy (PCNL, 22.10%), ureteroscope (URS, 22.65%), extracorporeal shockwave lithotripsy (ESWL, 18.60%) and conservative treatment (17.13%). In our case, the patient suffered from renal transplant lithiasis at 6 years posttransplantation, and the lithiasis recurred 16 months later. He presented oliguria, infection or acute renal failure (ARF) during the two attacks but without pain. PCNL along with URS and holmium laser lithotripsy were performed. The patient recovered well after surgery, except for a 3 mm residual stone in the calyx after the second surgery. He had normal renal function without any symptoms and was discharged with oral anticalculus drugs and strict follow-up at the clinic. Fortunately, the calculus passed spontaneously about 1 month later.

CONCLUSIONS

Due to the lack of specific symptoms in the early stage, patients with renal transplant lithiasis may have delayed diagnosis and present ARF. Minimally invasive treatment is optimal, and the combined usage of two or more procedures is beneficial for patients. After surgery, taking anticalculus drugs, correcting metabolic disorders and avoiding UIT are key measures to prevent the recurrence of lithiasis.