Factors predicting outcomes of micropercutaneous nephrolithotomy: results from a large single-centre experience

Microperc with Self-Assembled Fr 4.85 Visual Needle and Ureteral Access Sheath

BACKGROUND

Micropercutaneous nephrolithotomy (microperc) is the least invasive among percutaneous nephrolithotripsy (PCNL) procedures. Although microperc has a high stone-free rate and certain advantages over other methods, modifications may be needed to improve the technique. We describe our experience performing microperc using a self-assembled visual needle and ureteral access sheath (UAS).

METHODS

Between June 2016 and April 2019, the data of 30 patients with kidney stones undergoing microperc with our self-assembled 4.8 Fr visual needle combined with a UAS was retrospectively analyzed. Patients were placed in an obilique spine lithotomy position.

RESULTS

Two cases were excluded: one due to conversion to mini PCNL and the other required flexible ureteroscopy during microperc. The remaining 28 cases included 18 men and 10 women, age 38.4 ± 7.5 years, stone size 1.7 ± 0.4 cm, and stone density on CT 969 ± 233 HU. Operative time was 47 ± 9.9 minutes, visual analogue scale score of tract pain on postoperative day 1 was 2.5 ± 1.0, hemoglobin decrease was 6.4 ± 1.0 g/L, and hospital stay was 3.1 ± 0.8 days. There was 1 case of fever and urinary infection, 2 cases of hematuria, and 1 case of flank pain. All symptoms resolved after conservative or antibiotic treatment. On postoperative day 1, 12 (42.9%) caseswere stone-free. The stone-free rates at postoperative month 1 and 3 were 92.9% (26/28) and 100% (28/28), respectively.

CONCLUSIONS

Our self-assembled visual needle and UAS instrument is effective for microperc. Use of the UAS may improve the operative outcome.

Treatment of renal calculi without hydronephrosis using a standard channel assisted by a visual puncture system

Objective

To study the safety and efficacy of standard channel establishment using a visual puncture system in the treatment of renal calculi without hydronephrosis.

Methods

We retrospectively analyzed data from 46 patients undergoing percutaneous nephrolithotomy via a standard channel assisted by a visual puncture system, including number of punctures, duration of procedure, hemoglobin level after surgery, calculi clearance rate, and postoperative complications.

Results

Sixty-nine channels were established, including a single channel in 26 cases, double channel in 17 cases, and three channels in 3 cases. The mean number of punctures was 1.50, mean time to establish the standard channel was 2.6 minutes, and duration of surgery was 31.3 minutes. No significant change in hemoglobin was observed after surgery. Forty-three patients had no residual calculi and three had small residual calculi on the day after surgery, representing a first-phase clearance rate of 93.48% (43/46). No significant complications were observed.

Conclusions

Hemorrhage during operation can be significantly reduced by establishing a standard channel using a visual puncture system. Moreover, the number of standard channels can be reduced and the incidence of complications lowered using this approach, which should be adopted widely for the treatment of renal calculi without hydronephrosis.

Comparing micropercutaneous nephrolithotomy and retrograde intrarenal surgery in treating 1-2 cm solitary renal stones in pediatric patients younger than 3 years

INTRODUCTION

To compare the effects of micropercutaneous nephrolithotomy (micro-PCNL) and retrograde intrarenal surgery (RIRS) in treating 1-2 cm solitary renal stones in pediatric patients aged less than 3 years.

PATIENTS AND METHODS

A retrospective analysis was performed on data from 57 children younger than 3 years who received micro-PCNL and RIRS surgery in the authors hospital from October 2016 to August 2018. The patients were divided into group 1, the micro-PCNL group, and group 2, the RIRS group. Peri-operative data including surgical time, number of anesthesia sessions, stone-free rate (SFR), and complications were analyzed.

RESULTS

There were 27 patients in group 1 and 30 patients in group 2, and the patients' mean ages were 19 ± 9.9 months and 21 ± 7.8 months, respectively (P = 0.462). The stone size was 1.6 ± 0.3 cm in group 1 and 1.7 ± 0.2 cm in group 2 (P = 0.217); the mean surgical time was 52 ± 7 min in group 1 and 48 ± 9 min in group 2 (P = 0.163), and the mean lithotripsy time was 21 ± 4 min in group 1 and 23 ± 5 min in group 2 (P = 0.148); and the SFR at 1 month after surgery was 88.9% in group 1 and 86.7% in group 2 (P = 0.799). The number of anesthesia sessions for patients was 1.4 ± 0.5 in group 1 and 2.7 ± 0.5 in group 2 (P < 0.001). The complication rate was 14.8% and 16.7% in group 1 and group 2, respectively (P = 0.714). None of the patients needed conversion to the 12-14 F mini-PCNL.

CONCLUSIONS

The results of this study showed that the surgical effects and complications from micro-PCNL and RIRS in treating young children with 1-2 cm solitary renal stones were similar. However, micro-PCNL reduced the need to prestent before surgery and allowed lower anesthesia sessions. Therefore, micro-PCNL is an effective alternative method for 1-2 cm solitary renal stones in patients below 3 years of age.

Comparison among the available stone treatment techniques from the first European Association of Urology Section of Urolithiasis (EULIS) Survey: Do we have a Queen?

PURPOSE

The miniaturization of instruments has had an impact on stone management. The aims of this study were to highlight surgeon preferences among Retrograde Intra Renal Surgery (RIRS), Regular, Mini-, UltraMini- and Micro- Percutaneous Nephrolithotomy (PCNL) for urolithiasis and to compare the effectiveness and safety of these techniques in a real-life setting.

METHODS

A 12-item survey regarding endourological techniques was conducted through Survey Monkey among attendees of the 2013 European Association of Urology Section of Urolithiasis meeting. We asked responders to share data from the last 5 cases they performed for each technique. Procedures were stratified according to stone size and the centres' surgical volume. Techniques were compared in terms of effectiveness and safety. Analyses were performed on the overall group and a subgroup of 1-2 cm stones.

RESULTS

We collected data from a total of 420 procedures by 30, out of 78, urologists who received the survey (response rate 38%): 140 RIRS, 141 Regular-PCNL (>20 Ch), 67 Mini-PCNL (14-20 Ch), 28 UltraMini-PCNL (11-13 Ch) and 44 Micro-PCNL (4,8-8 Ch). Techniques choice was influenced by stone size and the centre's surgical volume. Effectiveness and safety outcomes were influenced by stone size, independently of the technique. The stone-free rate was significantly lower in Micro-PCNL compared to Regular-PCNL. This was not confirmed for 1-2 cm stones. All techniques presented a lower complication rate than Regular-PCNL, with Mini-PCNL being the most protective technique compared to Regular-PCNL.

CONCLUSIONS

Stone size seems to drive treatment choice. Miniaturized PCNL techniques are widely employed for 1-2 cm stones, in particular in higher surgical volume centres. Mini-PCNL and RIRS are growing in popularity for stones > 2 cm. Mini-PCNL seems to be a good compromise, being the most effective and safe procedure among PCNL techniques. RIRS is characterized by satisfactory stone-free and low complication rates.

Micropercutaneous nephrolithotomy versus retrograde intrarenal surgery in the treatment of renal stones: A systematic review and meta-analysis

Objective

To compare the efficacy and safety of micropercutaneous nephrolithotomy (Microperc) and retrograde intrarenal surgery (RIRS) in treating renal stones using published literature.

Methods

A systematic literature review was performed on August 21, 2017, using PubMed, Embase, and Cochrane Library databases in accordance with the PRISMA guidelines. Summarized mean differences (MDs) or odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the differences in outcomes between Microperc and RIRS.

Results

A total of nine studies (7 in adult patients and 2 in pediatric patients) containing 842 patients (381 Microperc cases and 461 RIRS cases) with renal stones were included in this analysis. Among the adult patients, Microperc was associated with higher stone-free rate(SFR)(OR: 1.6; 95% CI, 1.03 to 2.48), significantly longer hospital stays (MD: 0.66 day; 95% CI, 0.17 to 1.15), longer fluoroscopy time (MD: 78.12 s; 95% CI, 66.08 to 90.15), and larger decreases in hemoglobin (MD: 0.59 g/dl; 95% CI, 0.16 to 1.02) than was RIRS. No significant differences were observed with respect to operative time, stone-free rate, complication rate or auxiliary procedures.

Conclusions

Our results demonstrated that Microperc might be more effective in adult patients than RIRS will due to its higher SFR. However, longer hospital stays, longer fluoroscopy time and a larger decrease in hemoglobin should be considered cautiously.

"Microperc" micropercutaneous nephrolithotomy: a review of the literature

Recent years have seen innovations in working armamentarium of percutaneous nephrolithotomy (PCNL) leading to development of novel modifications such as miniperc, ultra miniperc, and microperc. Amongst these microperc appears to be least invasive and various authors, off late, have reported their experience with the technique. Literature on microperc was reviewed by a MEDLINE/PubMed search with articles in the English language since 2011 in published peer-reviewed journals. Articles comprised of case series, comparative, and noncomparative studies. Different facets encompassing the technique were analyzed including contemporary indications, technique and its modifications, outcomes, and comparison with other modalities. Technique is reported to be associated with high success rate (82-100%) and short hospital stay (1-2 days). Studies have reported minimal hemoglobin drop (0.1-1.4 gm%) and fewer complications of lower Clavien grades. Going small in PCNL has gone a long way to present day 4.85F puncture system. Utilization of this novel modification is on rise with larger case series and comparative analysis being reported in past 2 years. Technique boasts of high clearance rate, lower morbidity and short hospital stay. In the present era, this innovation in percutaneous stone management appears to be another milestone in quest for "knife to cannula to needle to nothing".

Small-calibre percutaneous nephrolithotomy (SC-PCNL). Therapeutic decision algorithm

INTRODUCTION

The progressive reduction in the calibre of the tract in percutaneous kidney surgery to the point of miniaturisation has expanded its use to smaller stones that until now have been treated with extracorporeal shock wave lithotripsy (ESWL) and retrograde intrarenal surgery (RIRS).

OBJECTIVE

To provide an update on the various techniques of small-calibre nephrolithotomy (SC-PCNL) analyse their efficacy, safety and indications and determine their degree of implantation at this time.

MATERIAL AND METHODS

We performed a review in PubMed of Spanish and English medical literature on the various techniques of SC-PCNL.

RESULTS

The use of SC-PCNL has reduced the morbidity associated with standard PCNL, particularly bleeding, and has enabled tubeless nephrolithotomy with greater safety. There are various techniques with blurred terminology (Miniperc, Microperc, Mini-microperc, Ultraminiperc), which differ in terms of gauge employed and in certain technical aspects that require their indications be specified. Currently, SC-PCNL competes with techniques that are less invasive than standard PCNL such as ESWL and the RIRS in treating small stones, but the role of SC-PCNL is still not sufficiently understood and continues to be the subject of debate.

CONCLUSIONS

The indications for PCNL are expanding to small stone sizes due to the miniaturisation of the technique. PCNL competes in this field with ESWL and RIRS. Larder studies are needed to establish the specific indications for PCNL in treating nephrolithiasis.

Retrograde intrarenal surgery and micro-percutaneous nephrolithotomy for renal lithiasis smaller than 2 CM

INTRODUCTION

Microperc is the upgraded form of percutaneous nephrolithotomy miniaturization. The aim of this study is to compare prospectively microperc and retrograde intrarenal surgery for the treatment of renal stones smaller than 2 cm.

MATERIAL AND METHODS

A comparative prospective study of both techniques was carried out between January 2014 and June 2015. Thirty-five patients were divided in two groups: Group A, 17 patients treated by retrograde intrarenal surgery and Group B, 18 patients treated by microperc. Stone clearance was assessed using CT scan 3 months after surgery.

RESULTS

Both groups were statistically comparable as demographic variables and stone size was similar (16.76 mm Group A vs 15.72 mm Group B). Success rate, hospital stay and JJ stenting were similar for both groups. There was no statistically significant difference regarding post-operatory complications: 17.64% Group A vs 5.56% Group B (p=0,062), all of them Clavien I and II. Surgical time was statistically different (63.82 min Group A vs 103.24 min Group B) as well as hemoglobin drop (0.62 g/dl Group A and 1.89 g/dl Group B).

CONCLUSION

Microperc is an effective and safe procedure for the treatment of renal lithiasis smaller than 2 cm, which makes it a good alternative to retrograde intrarenal surgery for this stone size. However, more prospective studies that include a larger cohort are necessary to confirm our results.

Extending indications of micropercutaneous nephrolithotomy: It is not just about cracking stones

Objective

To describe our experience and results of using the MicroPerc™ micropercutaneous nephrolithotomy armamentarium (PolyDiagnost, Germany) for unusual indications unexplored using this modality.

Patients and methods

We used the MicroPerc™ system for stone clearance in three ureteric calculi, two bladder calculi, one case of urethral calculus, for antegrade biopsy in a case of upper tract urothelial carcinoma, for Deflux® (dextranomer/hyaluronic copolymer, Salix Pharmaceuticals, Uppsala, Sweden) injection in three cases of vesico-ureteric reflux (VUR), and three cases of posterior urethral valve (PUV) fulgurations. A 4.85-F ‘All-Seeing Needle®’ (PolyDiagnost) was used in most of the cases. An 8-F mini-micro sheath was used where stability was deemed necessary. Clinical data were collected in a dedicated database. Intraoperative variables, postoperative complications, and outcomes were assessed.

Results

All patients were successfully treated with complete stone clearance at 1 month with no residual fragments. The antegrade biopsy confirmed a high-grade papillary neoplasm. There were no technical difficulties with injection of Deflux or PUV fulgurations. Follow-up at 1 year revealed no stone recurrence, resolved reflux in all three cases, and all the children that had had PUVs were voiding well. The small sample and retrospective nature of the analysis are the limitations of this study.

Conclusion

MicroPerc™, besides its usual use for minimally invasive percutaneous nephrolithotomy, can also be feasibly used for ureteric, bladder and urethral stones, and for treating non-calculus diseases such as PUVs and VUR. True to its name, it may be an ‘All-Seeing Needle’ in reality with much more to offer and harvest from.