Microperc Group Research Articles

A multi-institutional experience of Micro-percutaneous Nephrolithotomy (MicroPERC) for renal stones: Results and feasibility of day case surgery.

To report the multi-institutional outcomes of Microperc for nephrolithiasis and to assess its feasibility in outpatient care. We retrospectively identified all adult patients who underwent Microperc for renal stones at three centres between May 2015 and March 2021. Interventions were performed by three Surgeons. One Surgeon adopted a "one-way" strategy and all Microperc were performed on an outpatient basis, while the other two Surgeons provided inpatient monitoring for at least one day after surgery. The primary endpoint was same-day discharge after Microperc without emergency department visits or unplanned readmission within 30 days of the procedure. The secondary endpoints included treatment outcomes and the 30-day complication rate. Out of 72 consecutive patients included, 32 patients (44.4%) had same-day discharge. Median Charlson score (1 [0-2]) and cumulative stone size (15 [12-20] mm) were comparable between both groups. At one month post procedure, 32 patients (44.4%) were stone free and 23 patients (32%) had residual micro-fragments<3mm, conferring an overall success rate of 76.4% (inpatient Microperc group: 77.5% vs outpatient Microperc group: 75%, P=1). Analysis of the 30-day complication rate showed similar results between the two groups (Clavien I-II: 18.1%, Clavien≥III: 4.1%). After outpatient care, the rate of immediate admission and unplanned readmission was 12.5% (n=4), mainly due to urinary tract infection. In this multi-institutional study, we report that outpatient Microperc is feasible in selected patients with no significant impact on postoperative outcome.

Microperc versus miniperc for the management of medium-sized renal stones: a comparative two-center clinical study

Objective To date, there is very little evidence directly comparing the outcomes between Mini-percutaneous nephrolithotomy and Micro-percutaneous nephrolithotomy. Because of this evidence gap, we wanted to compare miniperc and microperc with an ultimate purpose to determine which modality is preferred for different stone characteristics. Our hope is that these findings may help guide which technique is most suitable for a given renal stone burden. Patients and methods This is a retrospective collaborative multi-institutional study between Dortmund Teaching Hospital (Germany) and Modena University Hospital (Italy) in which we compared two matched groups of patients. The first group (32 patients) underwent miniperc for medium-sized renal stones in Dortmund, and the second group (19 patients) underwent microperc in Modena. Both groups were matched according to age, sex, BMI, and maximum stone diameter according to preoperative plain KUB films. Results The primary stone-free rates in the miniperc and microperc groups were similar (93.8 vs. 84.2%, P = 0.262). Mean operative time for miniperc was significantly shorter than that of microperc (45.6 ± 18.9 vs. 68.7 ± 35.2 min, P = 0.004). The overall complication rate was 11.7%, with no significant difference between the two groups (12.5% for miniperc vs. 10.5% for microperc, P = 0.604). Mean hospital stay in miniperc was significantly longer than that of microperc (4.7 ± 1.6 vs. 3 ± 1.5 days,P Conclusion Our current data show that microperc is emerging as an effective and safe treatment option for intermediate-sized kidney stones, with outcomes comparable even to miniperc, which is already a well-established treatment with high safety profile in experienced hands.

A comparison of micro-PERC and retrograde intrarenal surgery results in pediatric patients with renal stones

With advancements in endoscopic surgery, open surgical techniques for urinary system stones have paved the way for the application of less invasive treatment modalities in patients with pediatric kidney stone disease. These treatment options include extracorporeal shock wave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL), and retrograde intrarenal surgery (RIRS). We aimed to compare the efficacy and safety of RIRS and micro-PCNL techniques in the surgical treatment of kidney stones in pediatric patients. A total of 48 pediatric patients, who underwent RIRS or micro-PERC for pediatric kidney stone disease, were retrospectively analyzed. Urinalysis, urine culture, serum creatinine (Cr), blood urea nitrogen (BUN), calcium, phosphorus, parathyroid hormone, 24-hour urine sample, complete blood count (CBC), urinary system X-ray, kidney ureter bladder (KUB), and urinary system ultrasonography (USG) test results were evaluated prior to the procedure. Intravenous pyelography (IVP), non-contrast computed tomography (CT), and renal scintigraphy evaluations were also performed, if necessary. The patients were divided into two groups: micro-PERC group (n=25) and RIRS group (n=23). Data relating to the duration of the operation, duration of fluoroscopy, length of hospitalization, complication rates, and stone-free rates were recorded. The mean ages of the micro-PERC and RIRS groups were 4±2.3 and 10.9±3 years, respectively (p=0.001). However, the mean stone sizes were 12.2±2.8 and 13.7±3.5mm, respectively (p>0.05). The mean duration of operation was 75.1±18.9min in the micro-PERC group and 62.3±15.3min in the RIRS group (p>0.05). In addition, the mean duration of fluoroscopy was 115±35.4s in the micro-PERC group and 39.9±15.3s in the RIRS group. The stone-free rates in the micro-PERC and RIRS groups following the procedure were reported to be 84% (21/25) and 82.6% (19/23), respectively (p>0.05). In terms of the degree of preoperative hydronephrosis between the groups, the rates of mild and moderate-severe disease were 76% (19 out of 25) and 24% (6 out of 25), and 69.5% (16 out of 23) and 30.4% (7 out of 23) in the micro-PERC and RIRS groups, respectively. In recent years, technological developments in minimally invasive procedures, such as micro-PERC and RIRS, have facilitated choices made by urologists in the effective and safe first-line treatment in pediatric patients.

Urinary kidney injury molecule-1 levels in renal stone patients.

To study kidney injury molecule-1 (KIM-1) biomarker levels, indicating renal tubular damage, in patients with kidney stones and in those who underwent minimally invasive method stone treatment. Sixty patients with renal stones between 10 and 20mm were included into the present study. Patients who were divided into three cohorts underwent micropercutaneous nephrolithotomy (microperc), retrograde intrarenal stone surgery (RIRS), and percutaneous nephrolithotomy (PNL). Urine samples were obtained from all participants before, 4h and 14days after the procedure. In all the samples obtained, urinary KIM-1 and creatinine (Cr) levels were measured and KIM-1/Cr ratios (ng/mg creatinine) were calculated. Preoperative urine KIM-1/Cr ratio was higher than postoperative 14th day. The bigger the renal stone size, the higher was the ratio (correlation coefficient 0.353, p=0.006). According to preferred treatment procedure, there was a statistically significant decrease in preoperative and postoperative 4th hour and 14th day urine KIM-1/Cr rates in the RIRS and PNL, yet none in the microperc group (p=0.010, p=0.001, p=0.212, respectively). In renal stone patients, the elevated urine KIM-1/Cr ratio levels increase further according to stone size. KIM-1/Cr ratio is a promising marker might be helpful in monitoring the damage created by stone disease.

A Comparison of 2 Percutaneous Nephrolithotomy Techniques for the Treatment of Pediatric Kidney Stones of Sizes 10-20 mm: Microperc vs Miniperc

To compare outcomes of micro-percutaneous nephrolithotomy (PNL; microperc) with mini-PNL (miniperc) in the treatment of pediatric renal stones of sizes 10-20 mm. Patients aged <18 years who underwent PNL for renal stones of sizes 10-20 mm between August 2011 and March 2014 in 3 referral centers were reviewed retrospectively. Patients were evaluated in the following 2 groups: microperc (group 1) and miniperc (group 2). Demographics and perioperative parameters (fluoroscopy and operation time, hemoglobin drop, and stone-free and complication rates) were retrospectively analyzed. A total of 119 patients were evaluated, including group 1 (n = 56) for microperc and group 2 (n = 63) for miniperc. We found mean stone sizes as 13.4 ± 3.4 and 14.8 ± 3.7 mm in the groups, respectively (P = .046). Mean operation and fluoroscopy times were 57.1 ± 31.2 minutes and 132.4 ± 92.5 seconds in the microperc group and 68.9 ± 36.7 minutes and 226.2 ± 166.2 seconds in the miniperc group, respectively (P = .110 and P <.001). Stone-free rates were similar in both groups (82.1% vs 87.3%; P = .433 and 92.8% vs 93.6%; P = 0673) on postoperative day 1 and at first-month follow-up. The mean hemoglobin drop in group 2 differed from that in group 1 significantly (P <.001). The difference of average hospitalization times was statistically significant (43.0 ± 15.4 vs 68.5 ± 31.7 hours; P <.001). Our outcomes show that microperc may be preferred as an alternative to mini-PNL for the treatment of pediatric kidney stones of sizes 10-20 mm with comparable success and complication rates, as well as shorter hospitalization and fluoroscopy times.

Contemporary Management of Medium-Sized (10-20 mm) Renal Stones: A Retrospective Multicenter Observational Study.

To evaluate contemporary management approaches to medium-sized (10-20 mm) renal stones. A total of 935 patients treated for medium-sized renal stones (10-20 mm) between July 2012 and March 2014 were included in the study program. Contemporary minimally invasive approaches applied in the management of such stones were evaluated and compared. The cohort consisted of 561 male (60%) and 374 female (40%) patients. Of the 935 patients with medium-sized renal calculi, 535 (57.2%) were treated with shockwave lithotripsy (SWL), 201 (21.4%) with retrograde intrarenal surgery (RIRS), 110 (11.7%) with minimally invasive percutaneous nephrolithotomy (miniperc), and the remaining 89 (11.7%) patients with micropercutaneous nephrolithotomy (microperc). In the SWL group, stones were located mostly in the pelvis (51%), while in the miniperc and microperc groups, they were located mainly in the lower pole (46%, 53%, respectively). Stone-free rates after a single session were 77.2%, 86.1%, 88.8%, and 83.6% in the SWL, RIRS, microperc, and miniperc groups, respectively. Although no serious complications (above Clavien level III) were noted in any of the groups evaluated, Clavien I to II complications were common in the miniperc group. Although SWL is the preferred treatment option for patients with medium-sized (10-20 mm) renal stones, endourologic methods also have been found to have a significant role. Relatively lower complication rates along with higher stone-free status observed with the RIRS technique compared with percutaneous approaches have made this method a valuable option in the management of such stones in recent years.

Comparison of intrarenal pelvic pressure during micro-percutaneous nephrolithotomy and conventional percutaneous nephrolithotomy

The micro-percutaneous nephrolithotomy (microperc) is a recently introduced percutaneous nephrolithotomy (PNL) technique that is performed through a 4.8 Fr all-seeing needle. We aimed to measure the intrarenal pelvic pressure (IPP) during microperc and compare it with the levels of conventional PNL. A total of 20 patients with 1- to 3-cm renal calculi resistant to shock wave lithotripsy were treated either with microperc (Group-1, n: 10) or conventional PNL (Group-2, n: 10) by the same surgical team. The IPP was measured during different stages (entrance into the collecting system, stone fragmentation, and before termination) of the procedures by an urodynamic machine using the 6 Fr ureteral catheter. All the variables were statistically compared between the two groups. The demographic values of the patients were similar. The operation time and duration of hospitalization were significantly prolonged in conventional PNL group (p = 0.034, p = 0.01, respectively). The mean drop in hematocrit levels was significantly lower in microperc group (3.5 ± 1.5 vs. 1.8 ± 0.8; p = 0.004). The IPP was significantly higher in microperc group during all steps of the procedure. The highest level of the IPP was measured as 30.3 ± 3.9 and 20.1 ± 3.1 mmHg in Group 1 and Group 2, respectively (p < 0.0001). However, the complication and success rates were found comparable. In conclusion, we demonstrate that the level of IPP is significantly increased during microperc compared to conventional PNL. Microperc should be used cautiously in cases with impaired drainage of the collecting system.

Comparison of Shockwave Lithotripsy and Microperc for Treatment of Kidney Stones in Children

We aimed to compare the outcomes of microperc and shockwave lithotripsy (SWL) for treatment of kidney stones in children. The medical records of 145 patients under the age of 15 years with opaque and single kidney stones treated with either SWL or microperc were retrospectively reviewed. Both groups were compared in terms of fluoroscopy and operative time, re-treatment, complications, success rate, and secondary and total number of procedures. Microperc and SWL were performed on 37 and 108 pediatric patients, respectively. The mean age of the patients was 5.91±4.03 years (1-15) and 8.43±4.84 (1-15) years in the SWL and microperc groups, respectively (P=0.004). The mean stone size was 11.32±2.84 (5-20) mm in the SWL group and 14.78±5.39 (6-32) mm in the microperc group (P<0.001). In the SWL group, 31 (28.7%) patients underwent a second SWL session and 6 (5%) had a third session. Finally, 95 (88%) patients were stone free at the end of the SWL sessions. In the microperc group, the stone-free rate was 89.2% in a single session (P=0.645). The mean duration of hospitalization was 49.2±12.3 (16-64) hours in the microperc group and 8.4±2.3 (6-10) hours per one session in the SWL group (P<0.001). The fluoroscopy time was significantly longer in the microperc group compared with the SWL group (147.3±95.3 seconds vs 59.6±25.9 seconds, P<0.001). The rate of requirement for an auxiliary procedure was higher in the SWL group than in the microperc group. The overall complication rates for the microperc and SWL groups were 21.6% and 16.7%, respectively (P=0.498). The results of our study demonstrate that microperc provides a similar stone-free rate and a lower additional treatment rate compared with SWL in the treatment of kidney stone disease in children.

Micropercutaneous nephrolithotomy (microperc) vs retrograde intrarenal surgery for the management of small renal calculi: a randomized controlled trial

To compare micropercutaneous nephrolithotomy (microperc) and retrograde intrarenal surgery (RIRS) for the management of renal calculi <1.5 cm with regard to stone clearance rates and surgical characteristics, complications and postoperative recovery. Seventy patients presenting with renal calculi <1.5 cm were equally randomized to a microperc or a RIRS group between February 2011 and August 2012 in this randomized controlled trial. Randomization was based on centralized computer-generated numbers. Patients and authors assessing the outcomes were not blinded to the procedure. Microperc was performed using a 4.85-F (16-gauge) needle with a 272-μm laser fibre. RIRS was performed using a uretero-renoscope. Variables studied were stone clearance rates, operating time, need for JJ stenting, intra-operative and postoperative complications (according to the Clavien-Dindo classification system), surgeon discomfort score, postoperative pain score, analgesic requirement and hospital stay. Stone clearance was assessed using ultrasonography and X-ray plain abdominal film of kidney, ureter and bladder at 3 months. There were 35 patients in each group. All the patients were included in the final analysis. The stone clearance rates in the microperc and RIRS groups were similar (97.1 vs 94.1%, P = 1.0). The mean [sd] operating time was similar between the groups (51.6 [18.5] vs 47.1 [17.5], P = 0.295). JJ stenting was required in a lower proportion of patients in the microperc group (20 vs 62.8%, P < 0.001). Intra-operative complications were a minor pelvic perforation in one patient and transient haematuria in two patients, all in the microperc group. One patient in each group required conversion to miniperc. One patient in the microperc group needed RIRS for small residual calculi 1 day after surgery. The decrease in haemoglobin was greater in the microperc group (0.96 vs 0.56 g/dL, P < 0.001). The incidence of postoperative fever (Clavien I) was similar in the two groups (8.6 vs 11.4%, P = 1.0). None of the patients in the study required blood transfusion. The mean [sd] postoperative pain score at 24 h was slightly higher in the microperc group (1.9 [1.2] vs 1.6 [0.8], P = 0.045). The mean [sd] analgesic requirement was higher in the microperc group (90 [72] vs 40 [41] mg tramadol, P < 0.001). The mean [sd] hospital stay was similar in the two groups (57 [22] vs 48 [18] h, P = 0.08). Microperc is a safe and effective alternative to RIRS for the management of small renal calculi and has similar stone clearance and complication rates when compared to RIRS. Microperc is associated with higher haemoglobin loss, increased pain and higher analgesic requirements, while RIRS is associated with a higher requirement for JJ stenting.