The current role of percutaneous chemolysis in the management of urolithiasis: review and results

International Alliance of Urolithiasis (IAU) guideline on staghorn calculi management

BACKGROUND

The stone burden based management strategy reported in the guidelines published by different associations is well known for a long time. Staghorn calculi, representing the largest burden and most complex stones, is one of the most challenging cases to practicing urologists in clinical practice. The International Alliance of Urolithiasis (IAU) has released a series of guidelines on the management of urolithiasis.

PURPOSE

To develop a series of recommendations for the contemporary management management of staghorn calculi and to provide a clinical framework for urologists treating patients with these complex stones.

METHODS

A comprehensive literature search for articles published in English between 01/01/1976 and 31/12/2022 in the PubMed, OVID, Embase and Medline database is performed. A series of recommendations are developed and individually graded following the review of literature and panel discussion.

RESULTS

The definition, pathogenesis, pathophysiology, preoperative evaluation, intraoperative treatment strategies and procedural advice, early postoperative management, follow up and prevention of stone recurrence are summarized in the present document.

CONCLUSION

A series of recommendations regarding the management of staghorn calculi, along with related commentary and supporting documentation offered in the present guideline is intended to provide a clinical framework for the practicing urologists in the management of staghorn calculi.

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.

Development of a nomogram predicting the infection stones in kidney for better clinical management: A retrospective study

PURPOSE

To establish the first comprehensive nomogram for prediction of infection stones before treatment for better perioperative treatment and post-operative prevention of infection stones.

METHODS

A total number of 461 patients with kidney stones who underwent mini-percutaneous nephrolithotomy (mPCNL) and flexible ureteroscopy (FURS) between January 2019 to March 2021 were retrospectively analyzed. Univariable analysis and multivariable logistic regression analysis were conducted to identify the predictors for infection stones. Furthermore, the nomogram was established as a predicted model for infection stones.

RESULTS

Among 461 patients with infrared spectroscopy stone analysis, 100 (21.70%) had infection stones and 361 (78.31%) had noninfection stones. Multivariate logistic regression analysis indicated that female (OR 2.816, 95% CI 1.148-6.909, P = 0.024), recurrent kidney stones (OR 8.263, 95% CI 2.295-29.745, P = 0.001), stone burden (OR 6.872, 95% CI 2.973-15.885, P < 0.001), Hounsfield units (HU) (OR 15.208, 95% CI 6.635-34.860, P < 0.001), positive preoperative bladder urine culture (PBUC) (OR 4.899, 95% CI 1.911-12.560, P = 0.001), positive urine leukocyte esterase (ULE) (OR 3.144, 95% CI 1.114-8.870, P = 0.030), urine pH (OR 2.692, 95% CI 1.573-4.608, P < 0.001) and positive urine turbidity (OR 3.295, 95% CI 1.207-8.998, P = 0.020) were predictors for infection stone.

CONCLUSIONS

For patients with kidney stones, female, recurrent kidney stones, stone burden (>601 mm2), HU (750-1000), positive PBUC, positive ULE, urine pH and positive urine turbidity were predictors for infection stone. We established the first comprehensive model for identifying infection stones in vivo, which is extremely useful for the management of infection stones.

Do organic substances act as a degradable binding matrix in calcium oxalate kidney stones?

BACKGROUND

Calcium oxalate (CaOx) stones are considered to be highly resistant to chemolysis. While significant organic matter has been identified within these stones, which is presumed to bind (inorganic) CaOx particles and aggregates, most chemolysis efforts have focused on methods to attack the CaOx components of a stone. We examine the feasibility of inducing chemolysis of CaOx kidney stones, within hours, by specifically attacking the organic matrix present in these stones.

METHODS

In contrast to previous studies, we focused on the possible "brick and mortar" stone configuration. We systematically tested, via in vitro experiments, the ability of an extensive range of 26 potential chemolysis agents to induce relatively fast disintegration (and/or dissolution) of a large set of natural CaOx stone fragments, extracted during endourological procedures, without regard to immediate clinical application. Each stone fragment was monitored for reduction in weight and other changes over 72 h.

RESULTS

We find that agents known to attack organic material have little, if any, effect on stone chemolysis. Similarly, protein and enzymatic agents, and oral additive medical treatments, have little immediate effect.

CONCLUSIONS

These findings suggest that the organic and inorganic constituents present in CaOx stones are not structured as "brick and mortar" configurations in terms of inorganic and organic components.

Non-surgical treatment of urinary stone

Some patients with urinary stones can be managed non-surgically through observation, medication, or extracorporeal shockwave lithotripsy (ESWL). Symptomatic urinary stones can initially be treated conservatively using analgesics and hydration. When uncontrolled pain or infection is present, immediate diversion via either percutaneous nephrostomy or ureteral stenting may be necessary. Medical expulsive therapy utilizing alpha-blocker may benefit a selected group of patients with stones larger than 5 mm. Oral or percutaneous chemolysis is a well-established non-invasive option with a reasonable success rate for patients with a certain component such as uric acid. When medical treatment is applied, its unintended side effects should be considered and routinely monitored. Extracorporeal shockwave lithotripsy is a highly effective and safe modality in treating urinary stones when adequately indicated. In addition to the size and location of the stone, information obtained from non-enhanced computed tomography such as stone density, stone heterogenicity index, and stone-to-skin distance can be applied to predict the possibility of ESWL failure. Modifications in shock wave delivery by altering shock rate and voltage can improve shock wave efficacy. Urinary stones can be managed effectively and safely using non-surgical approaches.

Kidney Stone Dissolution Therapy in Phosphate Stones: A Case Report

Background: Phosphate stones can be divided into struvite (7%), apatite (20%), and brushite stones (2%). They often present as large staghorn calculi and, therefore, can be challenging to treat. Moreover, it is crucial to obtain a stone-free patient to prevent recurrence. Therefore, local chemolysis can be an interesting tool when complete surgical removal of the stone is impossible or as an adjuvant treatment for residual stone fragments after surgery. Case Presentation: We present a case of an 84-year old Caucasian man in whom local chemolysis therapy with a citric acid solution resulted in a rapid reduction of the stone load, making less invasive therapy possible. Conclusion: We describe the procedure, (dis)advantages, and possible indications for local chemolysis.

Stone heterogeneity index on single-energy noncontrast computed tomography can be a positive predictor of urinary stone composition

The aim of this study was to investigate the correlation between stone composition and single-energy noncontrast computed tomography (NCCT) parameters, including stone heterogeneity index (SHI) and mean stone density (MSD), in patients with urinary calculi. We retrospectively reviewed medical records of 255 patients who underwent operations or procedures for urinary stones or had spontaneous stone passage between December 2014 and October 2015. Among these, 214 patients with urinary calculi who underwent NCCT and stone composition analyses were included in the study. Maximal stone length (MSL), mean stone density (MSD), and stone heterogeneity index (SHI) were determined on pretreatment NCCT. The mean MSD (454.68±177.80 HU) and SHI (115.82±96.31 HU) of uric acid stones were lower than those of all other types. Based on post hoc tests, MSD was lower for uric acid stones than for the other types (vs. CaOx: P<0.001; vs. infection stones: P<0.001). SHI was lower for uric acid stones than for the other types (vs. CaOx: P<0.001; vs. infection stones: P<0.001) Receiver operating characteristic curves of uric acid stones for MSD and SHI demonstrated that SHI (cut-off value: 140.4 HU) was superior to MSD (cut-off value: 572.3 HU) in predicting uric acid stones (P<0.001).

Nomogram to predict uric acid kidney stones based on patient's age, BMI and 24-hour urine profiles: A multicentre validation

INTRODUCTION

We performed a multicentre validation of a nomogram to predict uric acid kidney stones in two populations.

METHODS

We reviewed the kidney stone database of two institutions, searching for patients with kidney stones who had stone composition analysis and 24-hour urine collection from January 2010 to December 2013. A nomogram to predict uric acid kidneys stones based on patient age, body mass index (BMI), and 24-hour urine collection was tested. Receiver-operating curves (ROC) were performed.

RESULTS

We identified 445 patients, 355 from Cleveland, United States, and 90 from Sao Paulo, Brazil. Uric acid stone formers were 7.9% and 8.9%, respectively. Uric acid patients had a significantly higher age and BMI, as well as significant lower urinary calcium than calcium stone formers in both populations. Uric acid had significantly higher total points when scored according to the nomogram. ROC curves showed an area under the curve of 0.8 for Cleveland and 0.92 for Sao Paulo. The cutoff value that provided the highest sensitivity and specificity was 179 points and 192 for Cleveland and Sao Paulo, respectively. Using 180 points as a cutoff provided a sensitivity and specificity of 87.5% and 68% for Cleveland, and 100% and 42% for Sao Paulo. Higher cutoffs were associated with higher specificity. The main limitation of this study is that only patients from high volume hospitals with uric acid or calcium stones were included.

CONCLUSION

Predicting uric acid kidneys stone based on a nomogram, which includes only demographic data and 24-hour urine parameters, is feasible with a high degree of accuracy.