Percutaneous Nephrolithotripsy in Patients with Diabetes Mellitus

Research progress of percutaneous nephrolithotomy

Percutaneous nephrolithotomy (PCNL) is generally accepted as the gold standard treatment for the treatment of large kidney stones (> 2 cm). For nearly 40 years, with the continuous progress of technology and the constant updating of ideas, PCNL has made great progress. In this review, we discuss the current research progress, recent advancement and hot spot of the whole process of PCNL including anesthesia, position, puncture, dilation, lithotripsy approaches, perfusate, tube placement, hospitalization time, drug, treatment of residual stones, prognosis judgment and operation evaluation by summarizing the related research in this article.

Percutaneous Nephrolithotomy in Immunocompromised Patients: Outcomes from a Matched Case-Control Study

OBJECTIVE

To compare the outcomes of percutaneous nephrolithotomy (PCNL) in immunocompromised patients with those of PCNL in healthy population.

PATIENTS AND METHODS

A matched case-control study was performed from January 2009 through December 2014 using our prospectively collected kidney stone database. Patients with positive serology to human immunodeficiency virus (HIV), hepatitis C (cellular immune dysfunction), and patients on high dose of immunosuppressive drugs for treatment of autoimmune diseases composed the case group. Control group included patients with kidney stones and no other comorbidity. Patients were randomly matched based on Guy's score as a surrogate of case complexity.

RESULTS

Sixty-two patients were enrolled in this study, 21 cases and 42 controls. There were no significant differences in age, gender, and body mass index between groups. Regarding PCNL technique, there were no differences in patient positioning, number of accesses, and operative time. Complication rate was higher in the case group (38.1% vs 14.3%; p = 0.032); however, major complications, defined by Clavien score ≥3, were not statistically different (4.8% vs 2.4%; p = 0.611). There was a tendency of more postoperative urinary tract infection in the case group (19% vs 4.8%; p = 0.069). Mean decrease in hemoglobin level (3.3 vs 2.4 mg/dL; p = 0.037) and blood transfusion rate (23.8% vs 4.8%; p = 0.036) was significantly higher in the case group. Immunocompromised patients had a 2.8-fold increased risk of complications (odds ratio [OR] = 2.0, 95% confidence interval [CI] 1.01, 7.74) and a 5.8-fold increased risk of blood transfusion (OR = 5.8, 95% CI 1.29, 26.55). There were no differences in stone-free rate, nephrostomy tube time, and length of hospital stay.

CONCLUSION

Immunocompromised patients are at higher risk for complications such as bleeding after PCNL.

Factors affecting complications according to the modified Clavien classification in complete supine percutaneous nephrolithotomy

INTRODUCTION

An increase in percutaneous nephrolithotomy (PCNL) has been accompanied by an increase in complications. We identified the parameters affecting the severity of complications using the modified Clavien classification (MCC).

METHODS

From 2008 to 2013, 330 patients underwent complete supine PCNL using subcostal access, one-shot dilation, rigid nephroscopy, and pneumatic lithotripsy. We assessed the impact of the following factors on complication severity based on the MCC: age, gender, body mass index, hypertension, diabetes, previous stone surgery and extracorporeal shock wave lithotripsy, preoperative hemoglobin, renal dysfunction (creatinine >1.4 mg/dL), preoperative urinary tract infection, anatomic upper urinary tract abnormality (AUUTA), significant (moderate-severe) hydronephrosis, stone-related parameters (opacity, number, burden, location, staghorn, complex stones), anesthesia type, kidney side, imaging and calyx for access, tract number, tubeless approach, operative time, postoperative hemoglobin, and hemoglobin drop and stone-free results.

RESULTS

The complication rate was 19.7% (MCC: 0=80.3%, I=6.4%, II=11.2%, ≥III=2.1%). On univariate analyses, only the following factors affected MCC: gender, preoperative hemoglobin, AUUTA, significant hydronephrosis, imaging for access, calyx for access, tract number, postoperative hemoglobin, hemoglobin drop and stone-free result. Renal dysfunction was accompanied by higher complications, yet the results were not statistically significant. Multivariate logistic regression analysis demonstrated renal dysfunction, absence of significant hydronephrosis, AUUTA, multiple tracts, lower postoperative hemoglobin, and higher postoperative hemoglobin drop as the significant parameters which affected MCC and predicted higher grades. The paper's limitations include a low number of cases in the higher Clavien grades and some subgroups of variables, and not applying some techniques due to surgeon preference.

INTERPRETATION

Many of the complete supine PCNL complications were in the lower Clavien grades and major complications were uncommon. Renal dysfunction, AUUTA, significant hydronephrosis, tract number, postoperative hemoglobin, and hemoglobin drop were the only factors affecting MCC.

Percutaneous nephrolithotomy in high-risk patients: a single-center experience with more than 350 cases

PURPOSE

To assess the surgical outcomes and peri- and postoperative complications following percutaneous nephrolithotomy (PCNL) in high- and low-risk patients according to the American Society of Anesthesiologists (ASA) score.

MATERIALS AND METHODS

We reviewed the patient records of 2,281 cases older than 18 years who had undergone PCNL in the 3 previous years. The patients were divided into two groups: a low-risk group (ASA score 1, 2: 1,922 cases) and a high-risk group (ASA score 3, 4: 359 cases).

RESULTS

Analysis of the location and size of the stone, number and type of access, surgical approach, post-PCNL serum hemoglobin and decrease in glomerular filtration rate revealed no significant difference between the two groups. The stone-free rate was similar in both groups and the hospital stay in the high-risk patients was significantly greater than in the low-risk cases. 95% of low-risk and 91% of high-risk cases had surgical complications compatible with grade ≤II (Clavien system) and overall distribution of different grades of surgical complications was similar between the two groups (p = 0.177).

CONCLUSION

Success rate and surgical complications of PCNL in high-risk patients were comparable to low-risk patients. It seems that PCNL may be a safe and effective procedure even in high-risk patients.

Prospective evaluation of complications using the modified Clavien grading system, and of success rates of percutaneous nephrolithotomy using Guy's Stone Score: A single-center experience

INTRODUCTION AND OBJECTIVES

To prospectively document the perioperative complications of percutaneous nephrolithotomy (PCNL) using the modified Clavien grading system. Evaluation of complications and clearance rates according to stone complexity using the validated Guy's Stone Score (GSS) was also done.

MATERIALS AND METHODS

A total of 221 renal units underwent 278 PCNL procedures at a urology resident training center between September 2010 and September 2011 and data were recorded prospectively in our registry. Patients with co-morbidities like diabetes, renal failure, hypertension and cardiopulmonary diseases were excluded. Stone complexity was classified according to the GSS while peri-operative complications were recorded using the modified Clavien grading system.

RESULTS

Two hundred and forty-five complications were encountered in 278 PCNL procedures involving 116 renal units (41.72%). Complications of Grades 1, 2, 3a, 3b, 4a, 4b and 5 were seen in 52 (18.7%), 122 (43.8%), 42 (15.1%), 18 (6.4%), 6 (2.1%), 4 (1.4%) and 1 (0.3%) renal units respectively. There were 68, 98, 50 and 5 renal units in GSS I, II, III and IV groups, respectively. All grades of complications were more common in GSS III and IV (P<0.05). For GSS I, II, III and IV 100%, 74%, 56% and 0% of renal units, respectively, were stone-free after one session and 0%, 24%, 44% and 60% respectively needed two sessions to be stone-free.

CONCLUSION

Although the complication rates were higher most were of low grade and self-limiting. Complications were significantly more common with higher GSS and the GSS effectively predicted stone-free rates.

Renal stone disease and obesity: what is important for urologists and nephrologists?

Currently, obesity has reached an epidemic stage and represents a challenge for health authorities across the globe. Certainly, with emergence of obesity epidemic, we started to see an increase in the prevalence of chronic kidney disease (CKD) and nephrolithiasis. Interestingly, epidemiologic studies have shown that the incident stone risk increases with body mass index (BMI), and no further increase in risk is noticed when the BMI > 30 kg/m(2). Furthermore, metabolic syndrome and diabetes are also associated with an increase in the incidence of renal stones disease. The shared links between these metabolic disorders are insulin resistance. Furthermore, insulin resistance is thought to alter renal acid-base metabolism, resulting in a lower urine pH and increased risk of uric acid stone disease. Obesity is also associated with excess nutritional intake of lithogenic substances such as refined sugars, low fluid intake, calcium, oxalate, and purine-rich foods. Obesity is also associated with an increase in incidence of urinary tract infection. Recent reports suggested that renal stone disease carries risk of myocardial infarction, progression of CKD, and diabetes. Alarmingly, orlistat (obesity medication) and bariatric surgery are associated with hyperoxaluria and associated stone formation and even oxalate nephropathy. Certainly, the many health risks of obesity, including nephrolithiasis, will add more burden on urologists and nephrologists. Shockwave lithotripsy, percutaneous nephrolithotomy, and ureteroscopy are all safe procedures in obese individuals. Further research is urgently needed to address the pathophysiology and management of obesity-induced renal stones disease.

Beware the low urine pH--the major cause of the increased prevalence of nephrolithiasis in the patient with type 2 diabetes

There is an increased prevalence of nephrolithiasis and an increase in the incidence of renal colic in patients with diabetes, obesity, hypertension and insulin resistance because of an increased frequency of uric acid crystallization. Uric acid crystallization occurs in the milieu of an acid urine and is not due to hyperuricosuria as with insulin resistance, urinary uric acid levels are generally decreased because of increased renal tubular reabsorption. However, in the presence of insulin resistance, there is decreased renal tubular generation of ammonia and increased sodium absorption leading to acidification of the urine and uric acid crystallization. The presence of a low urine pH should alert the clinician to the increased risk of nephrolithiasis particularly in the obese, diabetic or hypertensive patient. Prevention of nephrolithiasis can be achieved in susceptible individuals either by alkalizing the urine and/or by further decreasing the uric acid content of the urine with a xanthine oxidase inhibitor such as allopurinol.

A comparison of the metabolic profiles of diabetic and non-diabetic uric acid stone formers

INTRODUCTION

The aim of this study was to compare the metabolic profiles of diabetic and non-diabetic patients with uric acid stones to understand whether preventive strategies should be tailored to reflect different causative factors.

METHODS

The results of the metabolic evaluation of patients with uric acid stones identified prospectively from the Metabolic Stone Clinic at St. Joseph's Hospital, London, Canada were reviewed. Information included patients' clinical histories, 24 hour urine collections, blood chemistry and stone analysis.

RESULTS

Complete data were obtained from 68 patients with uric acid stones. Twenty-two patients had diabetes. There were no statistically significant differences in mean age, body mass index, or history of gout. Among diabetics, pure uric acid stones were identified in 14 patients (63%) and mixed uric acid in 8 (36%). Pure uric acid stones were more common in the diabetic cohort (63% vs. 46%, p = 0.16). Urine pH, serum and urine uric acid levels and 24-hour urine volumes were similar in both groups. The diabetic group had an increased average oxalate excretion (424 μmol/d vs. 324 μmol/d, p = 0.003).

CONCLUSION

The exact etiological basis for the higher oxalate excretion in diabetic uric acid stone formers is unclear. Whether this is a metabolic feature of diabetes, due to dietary indiscretion or the iatrogenic consequence of dietary advice requires further investigation.

Prediction of morbidity and mortality after percutaneous nephrolithotomy by using the Charlson Comorbidity Index

OBJECTIVES

To determine whether the Charlson Comorbidity Index (CCI) predicts postoperative medical complications and death in patients treated with percutaneous nephrolithotomy (PCNL).

METHODS

A total of 1406 PCNL procedures were performed at 4-stone referral centers between September 2004 and March 2011 were reviewed in this multicenter study. Variables included patient and stone characteristics, preoperative comorbidities, intraoperative data, and postoperative complications, including mortality.

RESULTS

The present study included 868 (61.7%) men and 538 (38.3%) women. Mean patient age was 44.1 years (range 1-81). CCI score was calculated as "0" for 993 patients (70.6%, called group I), "1" for 316 patients (22.5%, called group II) and"≥2" for 97 patients (6.9%, called group III). The incidence of comorbidities increased with age (P=.001). The overall postoperative complication rate was 29.3%. Life-threatening medical complications developed in 2.9% of patients in group I, 7.6% of patients in group II, and 21.6% of patients in group III, (P=.001). There were 3 deaths for an overall 0.2% mortality rate. Perioperative bleeding requiring blood transfusion was observed in 9.5% of patients, and we found an increased risk of hemorrhage associated with CCI score (P=.049). High CCI score, patient age, hemorrhage, and operative time were significantly related to higher medical complication rates after PCNL.

CONCLUSIONS

CCI is a quick, simple, and reproducible scoring system that accurately predicts the morbidity and mortality of PCNL.