Percutaneous nephrolithotomy in infants and preschool age children: experience with a new technique

Current status of retrograde intrarenal surgery for management of nephrolithiasis in children

Purpose

To review the current status of retrograde intrarenal surgery (RIRS) for renal stones in children focusing on its indications, outcomes and success in the management of nephrolithiasis.

Materials and Methods

Between 1988 and 2009, a comprehensive PubMed/MEDLINE literature review on RIRS was conducted.

Results

The available literature is limited and heterogeneous, skewed by favorable results on ureteral stone outcomes. However, recent case series report outcomes comparable to time-honored modalities: percutaneous nephrolithotomy and shock wave lithotripsy. Concerns about urinary tract damage are not substantiated by the yet available intermediate-term follow-up.

Conclusions

RIRS seems to be an effective modality in pediatric nephrolithiasis management. However, long-term outcomes and comparative prospective randomized studies are awaited.

Surgical management of pediatric urolithiasis

Pediatric urolithiasis poses a technical challenge to the urologist. A review of the recent literature on the subject was performed to highlight the various treatment modalities in the management of pediatric stones. A Medline search was used to identify manuscripts dealing with management options such as percutaneous nephrolithotomy, shock wave lithotripsy, ureteroscopy and cystolithotripsy in pediatric stone diseases. We also share our experience on the subject.

Shock wave lithotripsy should be the treatment modality for renal stone less than 1cm or < 150 mm² and proximal non-impacted ureteric stone less than 1 cm with normal renal function, no infection and favorable anatomy. Indications for PCNL in children are large burden stone more than 2cm or more than 150mm² with or without hydronephrosis, urosepsis and renal insufficiency, more than 1cm impacted upper ureteric stone, failure of SWL and significant volume of residual stones after open surgery. Shock wave lithotripsy can be offered for more soft (< 900 HU on CT scan) renal stones between 1-2cm. Primary vesical stone more than 1cm can be tackled with percutaneous cystolithomy or open cystolithotomy. Open renal stone surgery can be done for renal stones with associated structural abnormalities, large burden infective and staghorn stones, large impacted proximal ureteric stone. The role of laparoscopic surgery for stone disease in children still needs to be explored.

Endoscopic stone management in children

PURPOSE OF REVIEW

The management of urolithiasis in children has significantly changed over the past 20 years. Extracorporeal shockwave lithotripsy (SWL) was initially the preferred modality of treatment. More recently, ureteroscopy and percutaneous nephrolithotomy (PCNL) are being used at an increasing frequency in the management of pediatric stone disease.

RECENT FINDINGS

Development has been made in various aspects of pediatric endoscopic stone management. Ureteroscopy and PCNL have been applied at an increasing frequency to treat pediatric stone disease, which has guided modifications to improve the procedures. Increased endoscopic experience with managing urolithiasis has broadened the indications wherein these methods are utilized. Technology is continually advancing to meet the needs of this population. Ureteroscopes have been modified to accommodate the pediatric ureter, optics advanced, and access sheaths are used to improve results. In addition, technique is constantly being refined.

SUMMARY

Further experience will direct surgeons as to when ureteroscopy and PCNL are appropriate. The incidence of urolithiasis is on the rise in developing nations; there is a need to address the most efficient method of treatment that minimizes the morbidity to the child.

Prospective comparative study of miniperc and standard PNL for treatment of 1 to 2 cm size renal stone

OBJECTIVE

• To evaluate the results of miniperc vis-à-vis standard PNL in the treatment of stones of 1-2 cm in size. Miniperc may represent a reasonable procedure in patients with nonbulky urolithiasis offering a similar outcome as standard percutaneous nephrolithotomy (PNL) with advantage of reduced morbidity.

PATIENTS AND METHODS

• 55 procedures including 27 miniperc and 28 standard PNL were performed for renal stones 1-2 cm in size. Pediatric patient, active urinary tract infection, renal malformation, uncorrected coagulopathy and morbid obesity patients were excluded from the study. • The parameters studied were demography, operative time, postoperative analgesic requirement, hemoglobin drop, complications and stone clearance.

RESULTS

• Mean tract size was 18.2 ± 2 F (15-20) and 26.8 ± 2 F (24-30), P value <0.0001 in the miniperc and standard PNL, respectively. Holmium LASER and pneumatic lithotripter were the main energy sources used in miniperc and standard PNL, respectively. • Miniperc operative time was longer than that of standard PNL (45.2 ± 12.6 vs 31 ± 16.6 min, P= 0.0008 respectively). • Conversely, there was an advantage of miniperc over standard PNL in terms of a significantly reduced hemoglobin drop (0.8 ± 0.9 vs 1.3 ± 0.4 gram%, P= 0.01), analgesic requirement (55.4 ± 50 vs 70.2 ± 52 mg tramadol, P= 0.29) and hospital stay (3.2 ± 0.8 vs 4.8 ± 0.6 days, P ≤ 0.001), respectively. • Intra- operative conversion of the procedure into a tubeless PNL was significantly more in the miniperc group (P ≤ 0.001). The miniperc and standard PNL group had clearance rates of 96% and 100%, respectively at 1 month follow up.

CONCLUSIONS

• This study demonstrated significant advantages of the miniperc procedure in terms of reduced bleeding leading to a tubeless procedure and reduced hospital stay. • The stone free rates and the complications were similar in either group.

Logistic regression model for predicting stone-free rate after minimally invasive percutaneous nephrolithotomy

OBJECTIVES

To investigate the prognostic factors associated with the treatment efficacy of minimally invasive percutaneous nephrolithotomy (MPCNL) and develop a preoperative logistic regression model for predicting the stone-free rate after the initial procedure.

METHODS

We retrospectively analyzed the records of 865 patients who had undergone MPCNL in our department from January 2006 to September 2009. Patient age, sex, body mass index, degree of hydronephrosis, and stone side, number, size, and location were the investigated variables. According to the treatment outcome, the patients were divided into 2 groups, those who became stone free and those who did not. Student's t test, chi-square test, and multiple logistic regression analysis were performed to determine the statistically significant variables and to develop a predictive mathematical model.

RESULTS

The stone-free rate after primary MPCNL was 80.1% (693 of 865). On univariate analysis, the stone number, size, and location and degree of hydronephrosis were identified as significant factors between the 2 groups. On multivariate analysis, they were also independent predictors of the surgical outcome. Next, a logistic regression model was developed using these variables to estimate the stone-free rate after MPCNL.

CONCLUSIONS

The results of our study have demonstrated that an increased stone number and size, location in a calix, staghorn calculus, and moderate to severe hydronephrosis were associated with decreased stone-free rates after MPCNL. We have developed a mathematical model for predicting the stone-free rate that will be helpful for patient counseling and surgeon decision-making regarding the management of upper urinary tract calculi.

Do patients benefit from miniaturized tubeless percutaneous nephrolithotomy? A comparative prospective study

BACKGROUND AND PURPOSE

A benefit of miniaturized percutaneous nephrolithotomy (MPCNL) compared with conventional percutaneous nephrolithotomy (PCNL) has not been demonstrated as yet. Thus, the aim of this study was to evaluate the outcome of conventional vs MPCNL and to determine if MPCNL offers an advantage for the patient.

PATIENTS AND METHODS

A prospective, nonrandomized series of 50 consecutive patients with solitary calculi (lower pole or the renal pelvis) were treated either by conventional PCNL (26F) or MPCNL (18F). Ultrasound or holmium laser were used for lithotripsy. Patients were treated tubeless after uncomplicated MPCNL, with thrombin-matrix tract closure and antegrade Double-J catheter placement. After PCNL, all patients received 22F nephrostomies. Demographic data, stone characteristics, perioperative course, and complication rates were assessed.

RESULTS

Patients characteristics were comparable in both groups, except for stone size, which was 18 +/- 8 mm (MPCNL) and 23 +/- 9 (PCNL; P = 0.042). Operative time was comparable in both groups (48 +/- 17 vs 57 +/- 22 min, not significant [NS]). After MPCNL, 96% were stone free at day 1 vs 92% after PCNL (NS). Significant complications did not occur in both groups. Minor complications were: Fever, 12% (MPCNL) vs 20% (PCNL; NS); bleeding, 4% vs 8%; perforations, 0% vs 4% (all NS). Overall outcome was not influenced by body mass index. Calcium oxalate stones were predominant with 75%. Patients after tubeless MPCNL had less pain (visual analogue score, 3 +/- 3 vs 4 +/- 3; P = 0.048.) and needed slightly less additional pain medication (25 +/- 12 mg/d vs 37 +/- 10 mg/d piritramid; NS). Hospital stay was significantly shorter after MPCNL (3.8 +/- 28 vs 6.9 +/- 3.5 d; P = 0.021.).

CONCLUSIONS

Both techniques were safe and effective for the management of renal calculi. While stone-free rates were comparable in our series, MPCNL showed advantages in terms of shorter hospital stay and postoperative pain. The lower stone burden and the tubeless fashion of MPCNL, however, might have influenced these results.

Tubeless mini percutaneous nephrolithotomy in infants and preschool children: a preliminary report

PURPOSE

We retrospectively analyzed the outcomes of tubeless mini percutaneous nephrolithotomy in infants and preschool children, and compared them with age matched controls who underwent nephrostomy drainage.

MATERIALS AND METHODS

A total of 28 renal units in 26 children were operated on for stone disease using the mini percutaneous nephrolithotomy technique. Holmium laser and pneumatic lithotriptor were used for stone fragmentation. Children who underwent complete stone removal and had a clear nephrostomy tract only had a ureteral catheter placed. Those with residual stones or bleeding from the nephrostomy tract underwent nephrostomy drainage. We compared both groups with regard to patient and stone characteristics, and postoperative findings.

RESULTS

A total of 12 renal units had only a ureteral catheter for diversion, while 16 had nephrostomy drainage. Mean respective ages of the stentless and nephrostomy groups were 3 (range 0.58 to 6) and 3.3 years (1.5 to 6). Mean respective stone burdens were 192 (range 100 to 400) and 416 (775 to 1,380) mm2. Surgery and fluoroscopy times were shorter in the tubeless group. Complication rates were higher (6 of 14 vs 0 of 12) and duration of hospitalization was longer (4.9 [range 3 to 14] vs 3.1 days [2 to 6]) in the nephrostomy group. Stone-free rates were 91.6% in the tubeless and 78.5% in the nephrostomy groups.

CONCLUSIONS

Tubeless percutaneous nephrolithotomy was observed to be a safe option for selected children with stone disease. The success and safety of tubeless percutaneous nephrolithotomy depends on patient selection criteria, including low volume and infection-free stones that are removed completely without any bleeding from the access tract.

Management of multiple stones in a single session using minimally invasive methods in infants with renal failure: renal salvage

The goal in the treatment of stone disease causing infantile obstructive uropathy is to obtain a quick resolution of the obstruction using the least invasive treatment modality available and rendering the patient stone-free, if possible. Two infants with bilateral kidney stones, the first of whom also had ureteral stone, were referred to our clinic with acute renal failure and were treated successfully in a single session using minimally invasive methods. In this report, we discuss the management of these two cases, aged 9 and 26 months, which resulted in favorable outcomes.

Safety and efficacy of percutaneous nephrolithotomy in infants, preschool age, and older children with different sizes of instruments

OBJECTIVES

To compare the morbidity and success rates among different age groups of children undergoing percutaneous nephrolithotomy (PCNL) using adult- or pediatric-sized devices. PCNL for renal stones in children may present problems because of small size, mobility of the pediatric kidney, and the small size of the collecting system.

METHODS

Patients were categorized into 2 age groups: those < or =7 years old at the time of PCNL (group 1, n = 17 [38.6%]), and those 8-16 years old (group 2, n = 27 [61.4%]). Group 2 children were further divided into subgroups according to the use of pediatric- (group 2a, n = 12 [27.3%]) or adult-sized devices (group 2 b, n = 15 [34.1%]).

RESULTS

Mean patient age was 4.1, 11.7, and 13.2 years in groups 1, 2a, and 2b, respectively. Fluoroscopy time, time to access the collecting system, operative time, and average postoperative hospital stay did not differ between the groups. However, hemoglobin decrease, bleeding during surgery, and blood transfusion rate was higher in group 2b. Stones were completely cleared in 82.4%, 83.3%, and 81.3% patients, and these percentages increased to 94.1%, 91.7%, and 93.7% with adjunctive shock wave lithotripsy and ureterorenoscopy in groups 1, 2a, and 2b, respectively.

CONCLUSIONS

Endourologic intervention in children usually requires instruments specific for preschool age; however, in older children with dilated collecting system, the use of adult instruments and techniques may achieve equal results.

Safety and efficacy of a superior caliceal puncture in pediatric percutaneous nephrolithotomy

BACKGROUND AND PURPOSE

Access through the superior calix for percutaneous nephrolithotomy (PCNL) often breaches the diaphragm and is believed to have greater complications than access through other calices. We evaluated the safety and efficacy of a superior caliceal access in pediatric patients who were undergoing PCNL.

PATIENTS AND METHODS

Operative and recovery data for pediatric patients (up to 16 years old) who were undergoing PCNL for renal calculi were prospectively entered into a database and reviewed. Patients with a superior calix puncture were compared with those in whom the superior calix was not punctured. Stone clearance was assessed by intraoperative fluoroscopy and postoperative radiography in all patients and ultrasonography and CT scan in selected cases.

RESULTS

Over a 2-year period, 26 pediatric patients (mean age 11.12 years; range 4-16 years) underwent 27 PCNLs. Stone bulk ranged from 200 to 1150 mm² (mean 656.03 mm²). Nine patients had staghorn stones. Thirteen patients (14 renal units) had primary superior calix access with 13 of these being supracostal (above the 12th rib). Four of these had staghorn calculus. All stones were fragmented using a pneumatic lithoclast. Second-look PCNL was necessary in two patients. Complete clearance was achieved in all except one patient in each group with superior and nonsuperior caliceal puncture. Hydrothorax developed in one patient with supracostal puncture necessitating tube drainage while abdominal collection developed in one in patient who underwent the nonsuperior calix approach. Both patients recovered with no sequelae.

CONCLUSIONS

The superior calix puncture is safe and effective in the pediatric population.

Contemporary surgical management of pediatric urolithiasis

With miniaturization of instruments and refinement of surgical technique, the management of pediatric stone disease has undergone a dramatic evolution. While shock wave lithotripsy (SWL) is still commonly used to treat upper tract calculi, the use of ureteroscopy (URS) has dramatically increased and is now the procedure of choice for upper tract stone burdens less than 1.5cm at centers with significant experience. Percutaneous nephrolithotomy (PCNL) has replaced open surgical techniques for the treatment of large stone burdens greater than 2cm, with efficacy and complication rates similar to the adult population. Large institutional series demonstrate comparable stone-free and complication rates with SWL, URS, and PCNL, but concerns remain with these techniques regarding renal development and damage to the pediatric urinary tract. Randomized controlled trials comparing the efficacy of SWL and URS for upper tract stone burdens are needed to reach consensus regarding the most effective primary treatment modality in children.

Pediatric urolithiasis: the current surgical management

Children represent about 1% of all patients with urolithiasis, but 100% of these children are considered high risk for recurrent stone formation, and it is crucial for them to receive a therapy that will render them stone free. In addition, a metabolic workup is necessary to ensure a tailored metaphylaxis to prevent or delay recurrence. The appropriate therapy depends on localization, size, and composition of the calculus, as well as on the anatomy of the urinary tract. In specialized centers, the whole range of extracorporeal shock-wave lithotripsy (ESWL), ureterorenoscopy (URS), and percutaneous nephrolithotomy (PCNL) are available for children, with the same efficiency and safety as in adults.

Status quo of percutaneous nephrolithotomy in children

Paediatric nephrolithiasis is quite challenging in terms of management because of the smaller size of the urinary tract and the bigger risk for stone recurrence. Children bear a higher risk of metabolic and infectious causes of stone disease and a longer lifetime risk for recurrence, especially in cases of residual fragments. Complete stone clearance should become the absolute objective and clinically insignificant residual fragments should be avoided. Nowadays, percutaneous nephrolithotomy (PCNL) arises as a logical first-line treatment option for considerable paediatric nephrolithiasis as miniaturization of endoscopes and advances in energy sources for stone fragmentation have facilitated stone-free rates. In this review we present the evolution of PCNL in children and we demonstrate its safety and efficacy. As appropriate instruments are available and relevant surgical experience is accumulating, age should no longer exist as a limiting factor for performing PCNL.

Long-term renal function and stone recurrence after percutaneous nephrolithotomy in patients with renal insufficiency

PURPOSE

We analyzed long-term results after percutaneous nephrolithotomy (PCNL) in patients with impaired renal function.

PATIENTS AND METHODS

Nineteen (6.3%) of 300 patients who underwent PCNL had serum creatinine values above 1.4 mg/dL before surgery and were considered to have impaired renal function. Success rate of operation, recurrence rate, and renal functional status were evaluated.

RESULTS

Mean follow-up time was 51.1 +/- 10.1 months. Sixteen patients completed the study, but three patients were lost to follow-up. The results of the operation were as follows: stone free in 50%, clinically insignificant residual fragments in 25%, and clinically significant residual fragments in 25% of the patients. Mean serum creatinine value was 2.30 +/- 0.56 mg/dL before surgery and 2.67 +/- 1.41 mg/dL at the end of follow-up (p = 0.386). Creatinine values decreased to normal range in six patients (37.5%). Six patients (37.5%) had stable renal function (creatinine: 1.4-4 mg/dL). Creatinine values increased (>4 mg/dL) in four patients (25%) who required renal replacement therapy. Three new patients progressed to end-stage renal failure. These three had insulin-dependent type II diabetes mellitus and one also had solitary kidney and atherosclerosis. Two patients (12.5%) had recurrences, one of these had hypercalciuria, and the other had infection stone.

CONCLUSION

Our results indicated that most patients presenting with kidney-stone disease and renal insufficiency experience improvement or stabilization of renal function after PCNL. The patients with solitary kidney and those with conditions such as diabetes and atherosclerosis might be at greater risk for deterioration of renal function. Patients with metabolic abnormalities and infection stones might be at higher risk for recurrence.

Chinese minimally invasive percutaneous nephrolithotomy: the Guangzhou experience

BACKGROUND AND PURPOSE

Percutaneous nephrolithotomy (PCNL) using a small tract is controversial, and its indication is considered limited. In our center, however, we have performed Chinese minimally invasive PCNL regularly for managing upper-tract calculi. We report our experience.

PATIENTS AND METHODS

Our technique is not just about using smaller instruments and tracts. Our overall approach is different from the standard PCNL. We preferred a middle caliceal puncture via the 11th rib space and also relied mainly on a strong irrigant current for stone fragment removal. We reviewed and analyzed the prospectively collected database on patients who underwent minimally invasive (MPCNL) from 2001 to 2005.

RESULTS

A total of 4760 MPCNL procedures were performed in 3610 kidneys. There were 1240 staghorn stones and 85 ureteral stones. There were 14 transplanted kidneys and 27 cases of horseshoe kidneys. The average operative time was 78 minutes. The stone-free rate at postoperative day 2 was 89%. The major complication rate was 0.86%.

CONCLUSION

Our experience with the Chinese MPCNL shows that it is safe and effective for managing all kinds of upper-tract calculi.

Renal drainage after percutaneous nephrolithotomy

Exit strategy after percutaneous nephrolithotomy (PCNL) is an area of continuing innovation to improve postoperative morbidity and operative outcomes for patients. The two important components of an exit strategy after PCNL are hemostasis and renal drainage. We review the different techniques of renal drainage after PCNL-ie, nephrostomy tube, ureteral stents, and totally tubeless strategy with critical discussion of available evidence for and against each of these techniques. We conclude that the optimal renal drainage method depends on patient characteristics and the operative course; hence, it should be individualized. To simplify this, we group patients undergoing PCNL as routine, problematic, and complicated, based on increasing complexity of the procedure and procedural complications. In routine PCNLs, we favor placement of an ureteral stent or a small-bore nephrostomy tube. In problematic and complicated PCNLs, we think the evidence directs toward placement of a nephrostomy tube, small bore being an option in problematic PCNLs.

Experience of percutaneous nephrolithotomy using adult-size instruments in children less than 5 years old

OBJECTIVE

We present our experience with percutaneous nephrolithotomy (PCNL) for management of large renal calculi in children less than 5 years old, and determine its safety and efficacy when using an adult-size device.

PATIENTS AND METHODS

Twenty patients younger than 5 years old underwent PCNL between August 2003 and July 2008. After retrograde catheterization, the nephrostomy tract dilated up to 26Fr. Then a 24-Fr rigid nephroscope was used and stones were fragmented with a pneumatic lithotripter.

RESULTS

Twenty patients with a mean age of 3.1 years underwent 26 PCNL procedures on 24 renal units. Four patients had bilateral renal stones. Five patients (20%) had staghorn stones, as did five of the other cases with multiple stones. Four patients had undergone previous stone surgery on the same side. All of the patients were managed with only one tract. The mean stone size was 33 (20-46)mm and average operative time was 93.25 (78-174)min. Stones were completely cleared in 79.16% of patients, which increased to 91.67% with adjunctive shockwave lithotripsy. The overall complication rate was 15.38% and mean hospital stay was 5.26 (3-8) days.

CONCLUSION

PCNL is an effective and safe treatment for renal calculi in children less than 5 years old, even when using instruments designed for adults.

[Minimally invasive percutaneous nephrolitholapaxy (MIP)]

Minimally invasive percutaneous nephrolithopaxy (MIP) was developed to combine the excellent stone-free rates of the conventional percutaneous nephrolithopaxy (PCNL) technique with the low morbidity of the miniaturized PCNL (Mini-Perc) and, at the same time, achieve a high level of patient comfort. The procedure is characterized not only by the diameter of the miniaturized 18-Fr Amplatz sheath that was adopted from the Mini-Perc but also by the following features: ultrasound-guided puncture of the kidney; single-step dilatation of the access tract; ballistic lithotripsy; a low-pressure irrigation system together with stone retraction by irrigation with a specially designed nephroscope sheath, for the so-called vacuum cleaner effect; and a sealed and tubeless access tract with primary closure of the channel independent of hemorrhage and without a second-look procedure.The results of the first 57 patients demonstrate primary stone-free rates of 92.9% with operating times averaging 62 (25-123) min. Severe complications, such as sepsis or bleeding requiring blood transfusion, did not occur. The high and predictable stone-free rate and a low morbidity comparable to that of ureteroscopy and extracorporeal shock-wave lithotripsy make MIP an attractive option for patients and urologists. The "vacuum cleaner effect" with quick removal of stone fragments reduces operating time and prevents new stone formation by avoiding residual fragments. The direct and primary closure of the access tract increases patient comfort and is justified by the reintervention rate of less than 8% in the presented cohort.The lack of a need for second-look nephroscopies, the vacuum cleaner effect, improved patient comfort without nephrostomy tubes, as well as surgery times comparable to that of traditional PCNL demonstrate a consequent evolution of the Mini-Perc. MIP therefore represents a promising and future-oriented module in modern stone therapy.

Endourological management of pediatric stone disease: present status

PURPOSE

The incidence of nephrolithiasis in the pediatric population has been steadily increasing. The miniaturization of endoscopic instruments and improvement in imaging modalities have facilitated safe and effective endourological treatment in this patient population. We reviewed the current status of pediatric stone disease management.

MATERIALS AND METHODS

A comprehensive literature review was performed using MEDLINE/PubMed to evaluate the indications, techniques, complications and efficacy of endourological stone management in children.

RESULTS

In the 1980s shock wave lithotripsy revolutionized stone management in children, becoming the procedure of choice for treating upper tract calculi less than 1.5 cm. Percutaneous nephrolithotomy has replaced open surgical techniques for the treatment of stone burdens greater than 1.5 cm with efficacy and complication rates mirroring those in the adult population. However, at an increasing number of centers ureteroscopy is now being performed in cases that previously would have been treated with shock wave lithotripsy or percutaneous nephrolithotomy. Results from recent retrospective series demonstrate that stone-free rates and complication rates with ureteroscopy are comparable to percutaneous nephrolithotomy and shock wave lithotripsy. Although concerns remain with all endoscopic techniques in children regarding damage to the urinary tract and renal development, neither short-term nor long-term adverse effects have been consistently reported.

CONCLUSIONS

Shock wave lithotripsy, percutaneous nephrolithotomy and ureteroscopy are highly effective endourological techniques to treat stone disease in the pediatric population. A lack of prospective randomized trials comparing treatment modalities coupled with a vast disparity in the access to resources worldwide continues to individualize rather than standardize stone treatment in children.

[PCNL: technical variations]

Since percutaneous nephrolithotomy (PCNL) was initially described, different technical modifications have been described. Among them, miniperc which only used small nephroscope and access sheath from 11 to 20Fr. This technique could not yet been recommended. Supine position is also a technical modification from original PCNL. Supine position is able to reduce colic injury and could be proposed in specific indications.

[Minimally invasive PCNL (mini-perc). Alternative treatment modality or replacement of conventional PCNL?]

Extracorporeal shock wave lithotripsy (SWL) is the current treatment modality of choice for upper urinary tract calculi. For stones with a diameter >2 cm and in lower calyceal stones and diverticular stones, the stone-free rate of SWL is rather poor. In these cases, conventional percutaneous nephrolithotomy (PCNL) leads to an increased stone-free rate, but morbidity with conventional PCNL is significant higher than in SWL. With the invention of miniaturized nephroscopes (mini-perc), new treatment options are available. The experience based on hundreds of treatments using mini-perc show comparable results of mini-perc to conventional PCNL and a complication rate comparable to that for SWL. These favorable results are independent of stone size, stone location, and patient age. In summary, mini-perc can be recommended as a primary approach to stones of the upper urinary tract exceeding 1 cm, larger lower-pole stones, and calyceal diverticular stones. Mini-perc can be regarded as an alternative treatment modality to conventional PCNL.

Extending the application of tubeless percutaneous nephrolithotomy

OBJECTIVES

Tubeless percutaneous nephrolithotomy (PCNL) has been successfully performed in selected patients. We assessed its applicability for use without imposing preoperative restrictions.

METHODS

The study consisted of a prospective and consecutive series of 126 patients. Tubeless PCNL was performed when perforation, residual stones, and significant bleeding had been intraoperatively excluded by fluoroscopy, nephroscopy, and hemodynamic assessment. Staghorn stones, supracostal and/or multiple access, anatomic anomalies, previously operated kidneys, solitary kidneys, and operative time were not considered contraindications. The demographic, clinical, and intraoperative and postoperative data were statistically analyzed.

RESULTS

Using this protocol, we performed 66 (52%) tubeless and 60 (48%) regular PCNLs. The average patient age (54 years versus 52 years), stone burden (924 versus 1044 mm2), operative time (116 versus 130 minutes), complication rate (9% versus 13%), hemoglobin decrease (1.2 versus 1.1 mg/dL), and immediate stone-free rate (92% versus 90%) were similar for the tubeless and regular PCNL groups, respectively (P >0.05). The reasons for performing standard PCNL were an expected second-look procedure (n = 35, 58%), an impression of active bleeding (n = 16, 27%), significant extravasation (n = 5, 8%), and suspected hydrothorax (n = 4, 7%). The overall transfusion rate was 3%. The average analgesia requirement (pethidine HCL) was 0.4 and 1.2 mg/kg (P <0.01), the median hospital stay was 1 and 4 days (P <0.0001), and the median back-to-work time was 7 and 15 days (P <0.001) for the tubeless and regular PCNL groups, respectively.

CONCLUSIONS

The results of our study have shown that tubeless PCNL can be safely and effectively performed based on intraoperative factors, without preoperative contraindications. Compared with the standard procedure, tubeless PCNL was associated with reduced postoperative pain, hospital stay, and recovery time.

Pediatric nephrolithiasis: does treatment affect renal growth?

OBJECTIVES

The long-term effects of shock wave lithotripsy on the growth of pediatric kidneys are not well defined. Likewise, no long-term data regarding renal growth after ureteroscopy or percutaneous nephrolithotomy have been published. We studied the effect of urolithiasis on renal growth in our pediatric patient population.

METHODS

A total of 165 children were treated for urolithiasis at St. Louis Children's Hospital from March 1993 to December 2003. Of these 165 children, 74 were available for long-term follow-up. Four groups were evaluated: those who underwent shock wave lithotripsy, ureteroscopy, or percutaneous nephrolithotomy, and those who received no intervention. The expected renal length was calculated using Chen's nomogram, and the observed renal length was measured using renal ultrasonography. All measurements were performed by one pediatric radiologist. The expected and observed renal growth was determined by subtracting the renal length at baseline from the length at follow-up, divided by the number of months of follow-up. Statistical analysis used paired data for each treatment group, and comparisons were made on a nonparametric single-rank method.

RESULTS

Of the 74 children, 39 were boys and 35 were girls, with a mean age at treatment of 9 years (range 9 months to 14 years) and a mean follow-up of 6.2 years (range 1.3 to 13.1). In all groups, the comparison between the treated side and nontreated side for expected and actual kidney size and growth was calculated as described. None of the groups had statistically significant differences in the observed or predicted renal growth rates.

CONCLUSIONS

Shock wave lithotripsy, ureteroscopic stone extraction, and percutaneous nephrolithotomy do not appear to impair renal growth.

Management of calyceal diverticular stones with extracorporeal shock wave lithotripsy and percutaneous nephrolithotomy: long-term outcome

OBJECTIVE

To review patients with an extended follow-up after extracorporeal shock wave lithotripsy (ESWL) or percutaneous nephrolithotomy (PCNL) for calyceal diverticular stones (CDS), over a 15-year period, assessing the long-term outcome.

PATIENTS AND METHODS

In all, 56 patients were treated for symptomatic CDS disease by ESWL (38) or PCNL (18). The stone-bearing diverticula were in the upper calyces in 26, middle calyces in 24 and lower calyces in six patients, and in the right kidney in 22 and in the left in 34. The most frequent symptom was ipsilateral flank pain (84%) and 32% of patients presented with associated chronic urinary tract infections. In a retrospective analysis, we assessed stone size, diverticulum location, stone-free rate, symptom-free rate, complications and extended follow-up.

RESULTS

In the short-term in the ESWL group, 21% of patients were stone-free and 61% were asymptomatic; 8% developed symptoms and 8% developed recurrence or stone-growth in the long term. There were six minor complications. In the PCNL group, 15 patients (83%) were stone-free in the short term; two had a recurrence (11%) and two had stone growth (11) in the long term. There were three complications after PCNL.

CONCLUSIONS

This series shows that PCNL is an effective and durable means of treating CDS, regardless of stone size or location of the diverticulum. Despite low stone-free rates with ESWL, most patients were rendered symptom-free with minimal complications. The long-term recurrence rates, 8% for ESWL and 11% for PCNL, were comparable.

Treatment of Symptomatic Caliceal Diverticula Using a Mini-Percutaneous Technique with Greater Than 3-Year Follow-Up

BACKGROUND AND PURPOSE

Caliceal diverticula can be treated with a variety of techniques. Traditional percutaneous techniques utilize nephrostomy-tract dilation to between 26F and 32F. Identification of a small diverticulum can be difficult after such dilation. The mini-percutaneous nephrolithotomy technique has been described for the treatment of nephrolithiasis. We report on two patients with caliceal diverticula treated using a mini-perc technique with long-term follow-up.

PATIENTS AND METHODS

Two symptomatic patients underwent treatment of posterior caliceal diverticula using a mini-perc technique. An interventional radiologist placed an 8F nephrostomy tube for access to the diverticulum. The following day, a 12F/14F ureteral access sheath was placed over a guidewire. Through the sheath, we identified the diverticulum and its neck with a 7F semirigid ureteroscope. The diverticular neck was balloon dilated to 18F, followed by fulguration with a 3F Bugbee electrode. A Double-J ureteral stent was placed antegrade from the diverticulum to the bladder, and an 8F nephrostomy tube provided external drainage.

RESULTS

The mean operative time was 138.5 minutes, and the mean estimated blood loss was 10 mL. Neither of the diverticula contained calculi. The mean length of stay was 2.5 days, and there were no complications. The hemoglobin and creatinine values showed no significant change. Both patients remained asymptomatic at a mean follow-up of 38 months.

CONCLUSION

Treatment of a caliceal diverticulum via a mini-perc technique is safe, effective technique with durable long-term results. It offers a less-invasive alternative to standard percutaneous treatment with larger access sheaths.

Third Prize: Contemporary Percutaneous Nephrolithotripsy: 1585 Procedures in 1338 Consecutive Patients

BACKGROUND AND PURPOSE

The approach to urinary-stone disease has changed dramatically over the last three decades with a transition from open surgery to minimally invasive procedures. Percutaneous nephrolithotripsy (PCNL) is a cornerstone of the treatment of kidney and selected upper-ureteral stones and continues to evolve with advances in techniques and instrumentation. The purpose of this study was to assess outcomes and trends prospectively in a large contemporary group of patients undergoing PCNL.

PATIENTS AND METHODS

Between July 1990 and December 2005, all 1338 patients at a single center scheduled for PCNL (N = 1585 procedures) were enrolled. Their mean age was 53 years (range 4-89 years). Data including comorbidities, stone burden, stone location, surgical time, hospital length of stay, rate of secondary procedures, and adverse events were collected prospectively. The primary outcome measures were stone-free rate and complications.

RESULTS

There was a substantial incidence of comorbid medical conditions (48.8%) and anatomic renal abnormalities (25.3%), demonstrating the diverse and challenging patient population in this contemporary series. The overall stone-free rate at 3 to 6 months of follow-up was 94.8%.

CONCLUSIONS

Percutaneous nephrolithotripsy is a highly effective procedure and may be performed in a diverse group of patients with comorbid conditions and renal abnormalities. Improved intracorporeal lithotripters, balloon dilation of the tract, use of flexible instruments, and liberal use of secondary nephroscopy result in excellent stone-free rates with low morbidity.

Minimally invasive percutaneous nephrolithotomy for staghorn calculi: a novel single session approach via multiple 14-18Fr tracts

OBJECTIVE

To report our experience with minimally invasive percutaneous nephrolithotomy (MPCNL) (14-18Fr percutaneous tract) to treat staghorn calculi via multiple percutaneous tracts in a single session procedure, and evaluate the feasibility and efficiency of this technique.

PATIENTS AND METHODS

From March 2001 to November 2005, 100 patients with staghorn calculi were treated by MPCNL via multiple percutaneous tracts. The size and location of the stone, operative parameters, number of tracts, stone-free rate, operating time, hospital stay, and complications were analyzed retrospectively.

RESULTS

A total of 209 percutaneous tracts were established in 100 renal units during 128 operations including 28 second-look procedures. The mean operating time was 107 minutes (range 43 to 130 min) and the mean hospital stay was 9.4 days (range 6 to 13 d). The initial stone clearance rate of 72% after the first session was improved to 93% after a second-look procedure in 28 patients. The mean blood loss was 112 mL (range 64 to 483 mL), 3 patients required blood transfusion and 1 patient with branched renal arterial injury during puncture received a highly elective embolism. Seven patients had a postoperative fever of 38.5 degrees C or greater, whereas 4 patients had mild hydropneumothorax.

CONCLUSIONS

With the development of instrument and increased experience, judiciously made multiple percutaneous tracts in a single session MPCNL for treating staghorn calculi in selected cases is safe, feasible, and efficient with an acceptable morbidity.

Introducing a new sealant applicator for easy, safe, and quick closure of a mini-percutaneous nephrolitholapaxy access tract

PURPOSE

To achieve better hemostasis after mini-percutaneous nephrolitholapaxy (mini-PCNL), we developed a new application device that can be used to close the renal-access tract with gelatin matrix hemostatic sealant (GMHS).

PATIENTS AND METHODS

After mini-PCNL was performed on 11 patients, a Double-J ureteral stent was placed antegrade. After retraction of the 18F Amplatz sheath out of the collecting system under vision without irrigation, the urothelium collapsed. The 15F metal applicator with a 10F working channel was then inserted and GMHS injected during further retraction of both the device and the Amplatz sheath. The skin was closed with Steri-strips.

RESULTS

The renal parenchymal tract of the mini-PCNL can be sealed in 15 to 50 seconds. Postoperatively, no urinoma was observed. All patients had an uneventful follow-up.

CONCLUSION

Closing the track of the mini-PCNL with the new application device and GMHS is a safe, easy, and quick alternative to the common nephrostomy tube.

Percutaneous nephrolithotomy in children: lessons learned in 5 years at a single institution

PURPOSE

We retrospectively compared morbidity and success rates in children who underwent percutaneous nephrolithotomy with 3 different sizes of instruments.

MATERIALS AND METHODS

Percutaneous nephrolithotomy was performed using adult instruments via a 26Fr tract in 23 patients, using pediatric instruments via a 20Fr tract in 13 and using minimal access (14Fr) in 10. Percutaneous nephrolithotomy was performed using general anesthesia with parenteral antibiotic prophylaxis. Cystoscopy and retrograde pyelography were performed, and 5Fr to 6Fr soft ureteral catheters were placed during each procedure initially. Percutaneous access was established via fluoroscopic guidance with the patient in the prone position. Pneumatic, ultrasonic and holmium laser lithotriptors were used for in situ lithotripsy. A 14Fr nephrostomy catheter was placed at the end of the procedure in the 26Fr and 20Fr groups, and in the minimal access group the ureteral stent was left indwelling in cases of atraumatic procedure with no residual fragments.

RESULTS

Mean patient age was 13.2, 5.9 and 6.3 years, respectively, in the 26Fr, 20Fr and minimal access groups (p=0.000). Sex distribution, previous surgery, stone size, surgery and fluoroscopy times, mean hemoglobin decrease and hospitalization time did not differ between the groups. However, blood transfusion rate was higher in groups 1 and 2. Stone-free rates were 69.5%, 80% and 90%, respectively, in groups 1 to 3. Overall, adjuvant shock wave lithotripsy treatment was needed in 3 children.

CONCLUSIONS

Smaller instrument size to 20Fr did not significantly increase the operative time, and resulted in the same success rates as the adult sized devices. However, low blood transfusion rates were only reached in the minimal access percutaneous nephrolithotomy group.

Management of pediatric stone disease

Pediatric and adult stone disease differs in both presentation and treatment. Children can present with a wide range of symptoms varying from flank pain and hematuria to nonspecific symptoms such as irritability and nausea. Although ultrasonography and plain radiographs can play a role in diagnosis and follow-up, the standard of care for a child who presents to the emergency department with a history suggestive of a stone is noncontrast spiral CT. Because there is a high yield in identifying predisposing factors in children with urolithiasis and high recurrence rates, metabolic evaluation of every child with a urinary stone should be undertaken and medical treatment should be given if necessary. With recent advances in technology, stone management has changed from an open surgical approach to less invasive procedures such as extracorporeal shock-wave lithotripsy and endoscopic techniques. Herein, we present a review of the recent literature and offer our own preferences to approaches for treatment.

"Ambulatory PCNL" (tubeless PCNL under regional anesthesia) -- a preliminary report of 10 cases

AIM

We report the technique, safety, outcome and efficacy of "tubeless percutaneous nephrolithotomy (PCNL) performed under regional anesthesia" in selected cases.

METHODS

Patients satisfying the entry criteria for the regional block (spinal low-dose anesthesia with low-dose Bupivacaine plus Fentanyl) and tubeless procedure were subjected to a tubeless spinal PCNL The patients were followed up the next day for an ultrasonography and an x-ray of the KUB region.

RESULTS

All the ten patients were discharged uneventfully the next day (mean hospital stay-40 h). No blood transfusion and postoperative analgesics (mean post op visual analogue pain score was 2.4) were required. The mean time to return of S(1) sensation, motor block and walking were 183,118 and 196.6 min respectively. There was complete stone clearance in all the cases with a mean collection of 14.5 cc was seen on the post op ultrasound.

CONCLUSIONS

The present cases were reported to highlight that in a select group of patients tubeless PCNL under regional block is technically feasible and viable option. Regional block has the advantage of avoidance of general anesthesia and anaphylaxis due to use of multiple drugs. Tubeless PCNL has the advantage of avoidance of nephrostomy tube related postoperative pain discomfort and urosepsis. This synergistically (spinal + tubeless PCNL) speeds up the recovery, shortens the length of hospitalization and the analgesic requirement.

Closing the tract of mini-percutaneous nephrolithotomy with gelatine matrix hemostatic sealant can replace nephrostomy tube placement

OBJECTIVES

To investigate the outcomes using gelatine matrix hemostatic sealant to close the tract after mini-percutaneous nephrolithotomy (mini-PCNL), resulting in a tubeless setting.

METHODS

After complete stone removal after mini-PCNL, a double-J ureteral stent was placed in an antegrade manner. After withdrawing the 17F Amplatz sheet from the collecting system under direct vision without irrigation, the urothelium collapsed. While retracting the sheet further, the gelatine matrix hemostatic sealant was injected. The skin incision was closed with glue. An ultrasound examination was performed on the first postoperative day to exclude the presence of urine extravasation.

RESULTS

Mini-PCNL was performed in 11 patients, either as a primary, small stone, single-access procedure or as a second-look mini-PCNL because of small residual fragments after extracorporeal shock wave lithotripsy. The time to seal the mini-PCNL tract through the kidney parenchyma was 2 to 5 minutes. The mean operative time was 79 minutes. In the first 5 cases, intravenous urography was performed in addition to ultrasonography and demonstrated an intact collecting system. The subsequent procedures demonstrated similar findings, with the exception of 1 case of temporary paravasation. In all other patients, the catheter was removed on the first postoperative day. Ten of 11 patients had an uneventful follow-up until removal of the double-J catheter. No major complications were observed.

CONCLUSIONS

Closing the tract of the mini-PCNL with gelatine matrix hemostatic sealant is a safe and fast alternative and provides the option of discharging the patient in good condition without the commonly used nephrostomy tube.

Treatment of renal stones in children: a comparison between percutaneous nephrolithotomy and shock wave lithotripsy

PURPOSE

We compared the results of percutaneous nephrolithotomy and shock wave lithotripsy for the treatment of 1 to 2 cm renal stones in children.

MATERIALS AND METHODS

The study included 166 children with renal stones 1 to 2 cm. A total of 75 patients (82 kidneys) were treated with percutaneous nephrolithotomy and 91 (93 kidneys) were treated with shock wave lithotripsy. Mean followup was 31 +/- 10 months (range 6 to 84). Both groups were compared regarding stone-free rate, re-treatment rate, complications and incidence of stone recurrence.

RESULTS

Both groups were comparable regarding preoperative characteristics. Of the units treated with percutaneous nephrolithotomy 4 (4.9%) were associated with minor complications. Stone-free rate after a single session of percutaneous nephrolithotomy was 86.6% (71 units), and the remaining 11 kidneys with residual stones were successfully treated with repeat percutaneous nephrolithotomy in 7 and shock wave lithotripsy in 4. Therefore, a total of 78 units (95%) were stone-free after percutaneous nephrolithotomy monotherapy, and the overall stone-free rate at 3 months was 100%. Of the patients undergoing shock wave lithotripsy 1 (1.1%) had development of steinstrasse and was successfully treated with ureteroscopy. The overall re-treatment rate after shock wave lithotripsy was 55%. A total of 79 units (84.9%) were stone-free after shock wave lithotripsy monotherapy, whereas 7 (7.5%) with no gross response to treatment were treated with percutaneous nephrolithotomy and 7 with insignificant stones less than 4 mm were followed. Therefore, the overall stone-free rate at 3 months was 92.5%. The differences in stone-free rates and re-treatment rates significantly favored percutaneous nephrolithotomy, while the incidence of complications and stone recurrence at last followup were not significantly different between the groups.

CONCLUSIONS

For treatment of 1 to 2 cm renal stones in children percutaneous nephrolithotomy is better than shock wave lithotripsy, yielding higher stone-free and lower re-treatment rates.