Systematic review and meta-analysis of percutaneous nephrolithotomy for patients in the supine versus prone position

Systematic review and meta-analysis of percutaneous nephrolithotomy in flank versus prone position

BACKGROUND

This systematic review and meta-analysis aimed to evaluate the efficiency and safety of percutaneous nephrolithotomy (PCNL) between flank position and prone position for the treatment of renal stones.

METHODS

PubMed, Embase, OVID, and Cochrane Library were comprehensively searched from their inception to Jul 2024. Randomized and nonrandomized trials evaluating renal calculi patients who underwent PCNL via flank position or prone position were included. Data extraction and quality assessment were conducted by two independent reviewers. The outcomes and complications of both groups were compared in this meta-analysis.

RESULTS

This review involved five articles (554 patients). Specifically, four articles were randomized controlled trials, and the remaining publication was prospective cohort study. No significant difference was found in stone-free rate between the flank group and prone group after the PCNL procedure. Similarly, the percutaneous access time, operative time, and hospital stay of flank position had no significant difference compared with the prone group. There was no significant difference in the comparison of complication rates between the flank group and the prone group. Although further analysis indicated that patients in the prone position suffered more hemoglobin drop than the flank group, no significant difference was found in the hemorrhage and blood transfusion rates.

CONCLUSIONS

Both surgical positions were appropriate for most PCNL procedures and had shown similar efficacy and safety. In practice, the optimal choice should be made according to the patients' conditions and urologists' acquaintance.

Supine versus prone pediatric percutaneous nephrolithotomy: A systematic review and meta-analysis

Percutaneous nephrolithotomy (PCNL) is the treatment of choice for pediatric nephrolithiasis more than 20 mm. Prone position was the preferred position for decades. Recently, supine position has gained more interest. This meta-analysis aims to evaluate the safety and efficacy of PCNL in supine versus prone position in pediatric population. A systematic search of PubMed, Scopus, Web of Science, and Cochrane Library was performed till 28 February 2024. The study included comparative studies comparing both positions in children that were written in English. A total of three randomized studies and three retrospective studies were included with a total number of 290 patients. Cochrane risk-of-bias tool for randomized trials was used for quality assessment, while Newcastle-Ottawa scale was used for non-randomized controlled trials. The meta-analysis was conducted using Review Manager software. Numerical data were analyzed using standardized mean difference (SMD), while the risk ratio was used for analysis of categorical data. Fixed or random effects models were used according to heterogeneity. There were statistically insignificant differences between both groups for stone-free rate (RR 1.08, 95% CI [0.98-1.18], p = 0.11) and overall complications (RR 0.93, 95% CI [0.59-1.47], p = 0.76). Operation time was significantly shorter in supine group (SMD -0.99, 95% CI [-1.67 to -0.30], p = 0.005). Therefore, comparable efficacy and safety outcomes were proved between both supine and prone positions for PCNL in pediatrics.

Prone vs supine percutaneous nephrolithotomy: does position affect renal pelvic pressures?

The purpose of this study was to measure and compare renal pelvic pressure (RPP) between prone and supine percutaneous nephrolithotomy (PCNL) in a benchtop model. Six identical silicone kidney models were placed into anatomically correct prone or supine torsos constructed from patient CT scans in the corresponding positions. A 30-Fr renal access sheath was placed in either the upper, middle, or lower pole calyx for both prone and supine positions. Two 9-mm BegoStones were placed in the respective calyx and RPPs were measured at baseline, irrigating with a rigid nephroscope, and irrigating with a flexible nephroscope. Five trials were conducted for each access in both prone and supine positions. The average baseline RPP in the prone position was significantly higher than the supine position (9.1 vs 2.7 mmHg; p < 0.001). Similarly, the average RPP in prone was significantly higher than supine when using both the rigid and flexible nephroscopes. When comparing RPPs for upper, middle, and lower pole access sites, there was no significant difference in pressures in either prone or supine positions (p > 0.05 for all). Overall, when combining all pressures at baseline and with irrigation, with all access sites and types of scopes, the mean RPP was significantly higher in the prone position compared to the supine position (14.0 vs 3.2 mmHg; p < 0.001). RPPs were significantly higher in the prone position compared to the supine position in all conditions tested. These differences in RPPs between prone and supine PCNL could in part explain the different clinical outcomes, including postoperative fever and stone-free rates.

Could pain change position choice? Comparison of pain level, analgesic requirement and hospitalization time in supine and prone percutaneous nephrolithotomy

PURPOSE

Investigation of how position affects postoperative pain levels and hospitalization in patients undergoing percutaneous nephrolithotomy (PNL) surgery.

METHODS

Between August 2019 and December 2022, a total of 156 patients who underwent prone (pPNL) and supine percutaneous nephrolithotomy (sPNL) due to kidney stones were included in the study. Demographic data, preoperative CT scans, laboratory results, transfusion rates, operation durations, complication rates, stone-free rates, analgesic use, nephrostomy removal time, hospitalization duration, fluoroscopy time, hemoglobin decrease and postoperative Visual Analog Scale (VAS) scores were evaluated for all patients. By comparing these data between the sPNL and pPNL groups, the effect of position selection in PNL on pain control, analgesic requirement, and hospitalization duration was examined.

RESULTS

In the comparison of the pPNL and sPNL groups, there was a significant difference between the two groups in body mass index, hounsfield unit, complication rate, analgesic rate, nephrostomy remove time, hospitalization time, operation time, fluoroscopy time and VAS score (p = 0.025, p < 0.001, p = 0.012, p = 0.012, p < 0.001, p < 0.001, p < 0.001, p < 0.001 and p < 0.001, respectively).

CONCLUSION

The shorter operation and hospitalization time in the sPNL group could be attributed to performing surgeries in a physiological position. Additionally, sPNL seems advantageous in terms of patients' pain levels, hospitalization time and VAS scores. One reason for this could be the different areas of access in sPNL and pPNL, which may correspond to different dermatome regions. Considering the low level of pain and reduced analgesic usage, sPNL appears to be advantageous.

Calcutta position: A new modified supine decubitus for supine PCNL

INTRODUCTION

PCNL (percutaneous nephrolithotripsy) is considered the gold standard treatment for renal stone more than 2 cm. In today's scenario, supine PCNL is considered equally effective as prone PCNL. The ideal position for supine PCNL is still debatable. We hereby describe our initial experiences of supine PCNL in a novel position.

METHODS AND MATERIALS

This prospective study includes 60 patients who underwent supine PCNL in the 'Calcutta position' in our institute from August 2021 to August 2022. Successful procedure was defined as a complete stone free rate or a clinically insignificant residual stone (<4 mm).

RESULTS

Average Operative room (OR) occupancy time was 130.9 ± 19.63 min. The immediate stone free rate was 84.2%, 71.4% and 37.5% for single, multiple and staghorn calculus respectively. Complications include fever, requirement of blood transfusions and renal colic. The average hospital stay was 83.6 ± 17.42 h. Eight patients (13.3%) required secondary procedures like extracorporeal shock wave lithotripsy (ESWL) or relook PCNL. At 3 months average stone free rates were 92%, 85%, 75% for single, multiple and staghorn calculus respectively. We performed supine PCNL in Calcutta position in obese, kyphoscoliosis, poliomyelitis, autosomal polycystic kidney disease (ADPKD), malrotated kidney and diverticular stone with comparable success.

CONCLUSION

Supine PCNL in Calcutta position is a safe and effective option for nephrolithiasis management. Apart from the inherent advantages of supine PCNL it also has the advantages of better C-Arm and nephroscope manoeuvrability. Supine PCNL in Calcutta position was performed in a variety of scenarios with comparable results.

Supine tubeless upper pole PCNL under spinal anaesthesia: Safety, feasibility and outcomes from a tertiary endourology centre

Objective

Supine Percutaneous Nephrolithotomy (PCNL) is being taken up by many urologists in recent times, but there is a tendency to shift to prone PCNL for upper pole puncture. We analyzed the safety, feasibility and outcomes of upper pole access in Supine Percutaneous Nephrolithotomy (sPCNL).

Materials and methods

A retrospective review of all patients undergoing sPCNL at a tertiary care center was done from January 2021 to December 2022. Data collection was done from the maintained imaging, laboratory and hospital records. All cases with complete data on upper pole access were included. Data analysis was done with Xlstat2021.

Results

50 patients with upper pole access were included (64%, 32 with single access and 36%, 18 with multiple accesses). The mean stone size was 23.88 ± 9.99, mean HU was 1093 ± 232.83, and the mean operative duration was 67.92 ± 34.62. Stone clearance rate was 98.82%, with all procedures performed tubeless.The mean haemoglobin drop was 0.75 ± 0.42 gm/dl with 2 (4%) patients needing a blood transfusion. The overall complication rate was 22% with only 1 Clavien Dindo III complication (1 pleural injury and hydrothorax needing USS guided aspiration) and others being Clavien Dindo I/II complications.

Conclusion

Supine PCNL is a feasible and safe approach for upper pole access. While the procedure can be done tubeless, these procedures must be done in experienced endourology units.

Gut microbiome characteristics in subjective cognitive decline, mild cognitive impairment and Alzheimer's disease: a systematic review and meta-analysis

BACKGROUND AND PURPOSE

The gut microbiome has been reported to be closely related to Alzheimer's disease (AD) progression. Here, a comprehensive meta-analysis of gut microbial characteristics in AD, mild cognitive impairment (MCI) and subjective cognitive decline (SCD) was performed to compare gut microbial alterations at each stage.

METHODS

A total of 10 databases (CNKI, WanFang, VIP, SinoMed, WOS, PubMed, Embase, Cochrane Library, PsycINFO and Void) were searched and 34 case-control studies were included. α and β diversity and the relative abundance of gut microbiota were analysed as outcome indices. Data analysis was performed using Review Manager (5.4.1) and R.

RESULTS

Chao1 and Shannon index levels in AD were significantly lower compared with healthy controls (HCs), and the Chao1 index was significantly lower in MCI compared with HCs. There was a significant difference in β diversity of gut microbiomes in patients (SCD, MCI, AD) compared with HCs. The relative abundance of Firmicutes at the phylum level was significantly lower in patients with AD and MCI than HCs. However, the relative abundance of Bacteroidetes at the phylum level was significantly higher in patients with MCI than HCs. There was an increasing trend for Enterobacteriaceae and a decreasing trend for Ruminococcaceae, Lachnospiraceae and Lactobacillus during AD; Lactobacillus showed a decreasing trend early in SCD.

CONCLUSION

Our results indicated that there were gut microbiological abnormalities in AD, even as early as the SCD stage. The dynamic, consistent changes in gut microbes with the disease process showed that they might serve as potential biomarkers for early identification and diagnosis of AD.

Which position is more advantageous for percutaneous nephrolithotomy: supine or prone?

Percutaneous nephrolithotomy (PNL) can be performed in a number of different positions. Our aim was to evaluate the convenience and advantages of the supine position following the transition from the prone to the supine position. 94 patients undergoing supine PNL (Group-1) and 93 patients undergoing prone PNL (Group-2) were retrospectively reviewed and included in the study. Patients who underwent mini-PNL (mPNL) were selected from Group-1 and Group-2 and divided into Group-1A supine mPNL patients (77) and Group-2A prone mPNL patients (53). Demographic characteristics, operative data and post-operative parameters were compared between these groups. The operation time was 74.4 ± 21.9 min in Group-1A and 79.2 ± 19.8 min in Group-2A (p = 0.076). The median value of fluoroscopy time was 30 s in Group-1A and 40 s in Group-2A (p = 0.003). In Group-1A, 59 patients had no intraoperative double-J stent (DJS) insertion and 18 patients had DJS insertion, while in Group-2A, 24 patients had no DJS insertion and 29 patients had DJS insertion (p < 0.001). MPNL was performed in 81.9% of patients in the supine position and 57% in the prone position. This difference was statistically significant (p < 0.001). No significant difference was found with regard to the success rate and the complications of mPNL. Fluoroscopy time is shorter in the supine position. Moreover, the insertion rates of DJS are low. With increasing experience, we have found that our standard PNL (sPNL) rate is gradually decreasing and more mPNL is being performed.

Modified Supine Percutaneous Nephrolithotomy in the Elderly: Outcomes and Safety

With increases in the aging population, conditions affecting older people and relevant surgical techniques are becoming more pertinent. Modified supine percutaneous nephrolithotomy (PCNL) is increasingly being adopted. There are limited data on the safety of this position in the elderly patient population. We describe our experience of the modified supine position in patients aged 70 years and older. Between April 2011 and March 2021, patients aged 70 years and older undergoing a modified supine PCNL performed by a single surgeon were prospectively evaluated. Data including patient age, operative time, complications, stone clearance, and length of stay were collected and analysed. Sixty-nine procedures were performed on 67 patients with a mean age was 76.5 years. Median total operative time was 95 min with 20 (29%) patients having a combined procedure with ureterorenoscopy. Preoperative mean stone burden was 23.5 mm and complete stone clearance was achieved in 46 (66.7%) patients. Twelve (17.4%) patients had complications during their hospitalisation. Six were Clavien-Dindo class II or less and one Clavien-Dindo class V. The modified supine position for PCNL is safe in the elderly patient population and has advantages including reduced handling of patients and achieving adequate stone-free rates. These benefits are particularly important in the elderly population, which frequently has a reduced tolerance to adaptation.

Comparative Study of Prone Position Variations for Percutaneous Nephrolithotomy

Objective

In this comparative study, we evaluated the results of flat prone and prone hip flexed percutaneous nephrolithotomy in terms of efficacy and safety to contribute to the optimal prone percutaneous nephrolithotomy position.

Materials and Methods

Data of the patients who underwent percutaneous nephrolithotomy operations in a flat-prone or prone hip flexed positions due to renal pelvis and/or ≥2 Calix filling stones between January 2016 and January 2022 were collected retrospectively. Demographic data of the patient groups in different prone positions as well as clinical findings, stone characteristics and operative data were analyzed. The groups were also compared in terms of post-operative findings and complications.

Results

The average age and CROES scores of patients included in the study were 47.15±15.6 years and 221.76±62.49, respectively. There was no statistically significant difference between the two groups in terms of patient demographic data, stone-free status and complication rates. Operation Room Time (ORT) (min) in flat prone PCNL group was shorter in average (100.57±32.74 min vs 92.32±28.75 min, p = 0.041) and duration with nephrostomy (days) and hospitalization (days) parameters were statistically significantly shorter in prone hip flexed PCNL (respectively, p < 0.001; p = 0.005).

Conclusion

Flat-prone PCNL provides significantly shorter ORT. However, the time with nephrostomy and hospitalization with the prone hip flexed PCNL were shorter than flat-prone position. The findings will guide the optimal prone PCNL position.

Stone attenuation on computer tomography helps surgeons make decisions between miniaturized percutaneous nephrolithotomy or retrograde intrarenal surgery for lower pole stones: a retrospective study

A retrospective study was performed on 200 patients who underwent miniaturized percutaneous nephrolithotomy (mini-PCNL) or retrograde intrarenal surgery (RIRS) for 10-20 mm sized lower pole renal calculi to investigate the relationship between computed tomography (CT) attenuation of calculi and surgical outcomes. CT was used to examine the location, size, and CT attenuation values of the calculi. Additionally, the operation time, hospital stay, hemoglobin (Hb) reduction, stone-free rate (SFR), and complication rate were also meticulously documented and subjected to comparative analysis. Complications were assessed using the Clavien-Dindo grading system. We observed no significant differences in hospitalization data and follow-up outcomes, except for a longer hospital stay and higher Hb drops in patients receiving mini-PCNL. Statistical analysis revealed an association between CT attenuation and operation time. Compared with mini-PCNL, RIRS could reduce bleeding, hospital stay, surgery time, and complications for 10-20 mm sized lower pole kidney stones with CT values < 1000 HU. RIRS resulted in longer operation time and lower stone-free rates despite shorter hospital stays and less bleeding than mini-PCNL for stones with CT values > 1000 HU. Therefore, selecting an appropriate surgical method based on CT attenuation might improve outcomes. For patients with stone attenuation values < 1000 HU, RIRS is the recommended option. When stone attenuation values > 1000 HU, the surgical method should be chosen based on the patient's individual situation.

Is supine position safe and effective for the percutaneous nephrolithotomy? Clinical experiences, tip and tricks in learning curve and PSAA technique

AIM

The aim of this study was to determine the factors facilitating the supine percutaneous nephrolithotomy technique in learning curve, to compare the supine and prone technique results.

MATERIAL AND METHODS

47 patients who required percutaneous nephrolithotomy were included in this study, and they were divided into two groups as supine and prone. Prone technique was performed to 24 patients in the first group. In the second group, the supine technique was performed by calculating the patient-specific access angle for 23 patients. Demographic, preoperative, intraoperative, postoperative parameters, transfusion, and complications of both groups were compared.

RESULTS

Age, gender, side, stone size, stone-free rate, and length of stay in hospital were not statistically significant between the groups. Operation and fluoroscopy time were lower in the supine group, but it was not statistically significant. The decrease in hemoglobin was higher in the supine group and it was statistically significant (p = 0.027). The decrease in hemoglobin was not symptomatic in both groups. In addition, transfusion rates were similar and not statistically significant.

DISCUSSION

In previous studies, the supine technique was evaluated in terms of many factors. Process steps were tried to be standardized and improvements were made in the access technique. The supine technique, which uses patient-specific access angle, has similar complication rates as the prone technique. However, the operation and fluoroscopy times are shorter than the prone technique. For surgeons on the learning curve, the supine technique is safe, feasible, and has even shorter operating times with a patient-specific access angle.

An Observational Pilot Study on Supine Percutaneous Nephrolithotomy: Initial Experience at a Single-Centre

Objective To assess the surgical outcome of supine percutaneous nephrolithotomy (PCNL) in patients with co-morbidities. Materials and methods We retrospectively reviewed the data of 15 patients who underwent supine PCNL at our centre from September 2019 to May 2021. Preoperatively, a complete examination of the patients, along with biochemical and radiological investigations, was done. The data, which included patient demographics, comorbidities, complexity of renal calculi, complications, and stone clearance rate, were collected from the patients' medical records. Results Patients aged between 31 and 70 years were included in the study. The mean (SD) BMI was 26.01 (2.31). Twelve patients (80%) were overweight with a BMI of 25.3 to 29.3 kg/m². The most common comorbidities were diabetes (33.3%) and hypertension (26.7%). In our study, six patients were American Society of Anesthesiologists (ASA) grade 3 (40%), followed by grade 2 in five patients (33.3%), grade 4, and grade 1 in two patients (13.3%) each. The Guy's Stone score was one in nine patients (60%) and two in six patients (40%). Complete clearance was achieved in 13 (86.7%) patients. Two patients (13.3%) had a stone clearance of more than 80%. Data analysis showed that 14 patients (93.3%) had no perioperative complications. Postoperative abdominal distension was noted in one patient (6.7%), which was managed conservatively (Clavien-Dindo grade 1). We did not encounter any cases of organ injury following supine PCNL. Postoperatively, none of our patients received blood transfusions. Conclusion Our study shows that supine PCNL is a good surgical option, especially for high-risk patients with good stone clearance and low complication rates.

Position-related anesthesiologic considerations and surgical outcomes of prone percutaneous nephrolithotomy: a review of the current literature

The aim of the current study was to perform a critical review of existing literature and report the potential morbidity of patient positioning during urological surgeries as well as evaluate the surgical outcomes and anesthesiologic benefits and risks of prone percutaneous nephrolithotomy (PCNL). A narrative review of the current literature has been performed. Articles related to position-related injuries and complications under general anesthesia in prone positions were selected, studied, and considered for the current review. We found that under general anesthesia, the prone position improved the oxygenation of patients and increased the elimination of carbon dioxide. A potential risk for position-related anesthesiologic side effects was reported for longer spine surgeries in a prone position. The injuries and position-related side effects were extremely rare following prone PCNL since the mean duration of the procedure was significantly shorter than that of spine surgery. In conclusion, the prone PCNL remains the most often utilized and preferred approach globally with well-established success and complication rates. Clinical outcomes of prone PCNL do not demonstrate an increased rate of anesthesiologic complications compared to the supine approach. Standardization of turnover of the position, and reduction of the operative time warrant a faster and complication-free recovery.

Worldwide practice patterns of percutaneous nephrolithotomy

PURPOSE

To evaluate the current practice of percutaneous nephrolithotomy (PCNL), conducting a worldwide survey among urologists with a special interest in endo-urology.

METHODS

A 22-question survey was specifically developed by the European Association of Urology (EAU) young academic urologists (YAU) and uro-technology (ESUT) groups and globally distributed via SurveyMonkey to almost 2000 members of Endourology Society. The questionnaire included questions dedicated to the demographics and general practice of the participating urologists.

RESULTS

In total, 441 responses (male/female ratio - 418/23) were received. A comparatively higher percentage of specialists (56.2%) practiced in academic institutions and had specific endo-urological fellowship training (56.7%). The classical prone PCNL remained the most practiced approach among the surveyed specialists, 47.7% stated to always do prone PCNLs, while 51.8% of respondents used multiple positioning options as required. The PCNL tract was mostly performed by urologists (84.3%) and fluoroscopic guidance was still predominantly used by 74.5% of respondents. The most practiced tract dilation method was balloon dilator used by 42% of respondents. Most of the surveyed urologists had ultrasonic, pneumatic or laser lithotripsy devices in their armamentarium. The use of some form of post-procedural drainage was reported in 85.1% of respondents, whereas tubeless PCNL remained a fairly uncommon practice.

CONCLUSION

The majority of urologists still use prone positioning, get their own access under fluoroscopy guidance and use a balloon for tract dilation. However, we also identified that when necessary, urologists will deviate from routine practice and change strategy, adopting other approaches for PCNL.

Pediatric Stone Surgery: What Is Hot and What Is Not

PURPOSE OF REVIEW

We aim to highlight recent advances in technology and techniques for surgical management of urinary tract calculi in pediatric patients.

RECENT FINDINGS

Percutaneous nephrolithotomy (PCNL) is classically performed in the prone position. The supine PCNL was first attempted to overcome the shortcomings of difficult airway access, patient and surgeon discomfort. The supine PCNL, and subsequent modifications, has been successfully described in the pediatric population. Classically, PCNL has also been classically concluded with obligate placement of a nephrostomy tube and bladder catheter. Recently, tubeless and totally tubeless PCNL reduces pain and duration of hospitalization with satisfactory surgical outcomes in children. Finally, we describe the use of thulium laser technology, which offers improved efficacy in stone treatment and may supplant the current dominant technologies in coming years. Recent advances in pediatric stone surgery include supine PCNL, miniaturized PCNL instrumentation, tubeless procedures, and thulium laser technology.

Evaluation and comparison of S.T.O.N.E. and Guy's scoring systems for predicting percutaneous nephrolithotomy outcomes in supine position

BACKGROUND

Percutaneous nephrolithotomy (PCNL) was applied in the prone position until recently. But also, in recent years supine positions was applied in patients with kidney stones. Predicting how much renal stones can be cleared after surgery and possibility of complications is an important question for both surgeons and patients. Therefore different scoring systems are used to evaluate outcomes of PCNL before surgery.

PATIENTS AND METHODS

Between 2018 and 2020, 80 patients with renal stone who underwent PCNL in the supine position were evaluated preoperatively by S.T.O.N.E. and Guy's scoring systems (GSS). The predictions of both scoring systems for stone-free and complication rates in patients who underwent PCNL in the supine position were evaluated. Also, these scoring systems were compared among themselves for reliability.

RESULT

In both scoring systems, there was a statistically significant difference between postoperative stone-free (SF) and residual stone (RS) of patients and in predicting the likelihood of complications in patients. No statistically significant difference was found between the two scoring systems in predicting the stone-free rate.

CONCLUSION

Our findings revealed that S.T.O.N.E. nephrolithometry and Guy's score systems can be used effectively to predict stone-free rate, complications, and operation duration in supine position PCNL for renal stones.

A prospective, randomized comparison of standard prone position versus flank-free modified supine position in percutaneous nephrolithotomy: A single-center initial experience

Background:

Percutaneous nephrolithotomy (PCNL) is the first choice for treatment of large renal stone >2 cm. The prone position is the classical position preferred by most surgeons. Aiming to improve patient anesthesia and surgery-related inconveniences of the prone position, Valdivia et al., 1987, described the performance of PCNL with the patient in the supine position. Hence, we aimed to study the safety and efficacy of flank-free modified supine position in PCNL compared to the standard prone position.

Patients and Methods:

This is a prospective randomized study for 60 patients with large renal stones planned for PCNL operation during the period from November 2017 to May 2019. Patients were divided into two groups (30 patients each group): Group A – patients underwent PCNL in the prone position and Group B – patients underwent PCNL in the modified flank supine position. Patients’ demographics, stone size, Hounsfield unit with intraoperative details as fluoroscopy time, operative time, and complications were recorded. Postoperatively, need for or not to blood transfusions, hospital stay, stone-free status, and postoperative complications were assessed.

Results:

There was no statistically significant difference between the prone and supine positions regarding stone size (4 cm vs. 4.5 cm, P = 0.16), Hounsfield unit (940 HU vs. 955 HU, P = 0.78), body mass index (31.2 kg/m² vs. 32.5 kg/m², P = 0.49), fluoroscopy time (6.9 min vs. 7.3 min, P = 0.5), operative time (89.5 min vs. 90.4 min, P = 0.9), residual stones (10% vs. 20%, P = 0.8), and hospital stay (45.6 h vs. 48.6 h, P = 0.5). Fever occurred in 3.3% of cases in each group and urine leakage observed in one patient with prone position. No blood transfusion was needed in both the groups.

Conclusions:

PCNL in the modified supine position proved to be a safe and effective choice compared to the prone position for adult patients with large renal calculi.

One-shot dilatation versus metal dilator during percutaneous nephrolithotomy in Flank-free supine position: A Randomized Controlled Study

BACKGROUND

The creation and dilatation of the nephrostomy tract is a fundamental step in PCNL. In one-shot dilatation (OSD), we used a single Amplatz dilator over a central Alken rod. PCNL in the supine position is as effective and safe as in the prone position. The Barts flank-free modified supine position sum several advantages of the different supine positions. We evaluated the efficacy and safety of OSD compared to metal telescopic dilatation (MTD) during PCNL while the patient was in Barts flank-free modified supine position.

MATERIALS AND METHODS

Within 2.5 years, 150 patients with kidney stones candidates for PCNL were randomized into two equal groups according to the dilatation technique. In the OSD group, dilatation was performed using a single Amplatz dilator (30 Fr) and in the MTD group dilatation was performed by sequential MTD (9-30 Fr). All PCNL procedures were done with patients in Barts flank-free modified supine position. Patient characteristics, operative data, and results were collected for statistical analysis.

RESULTS

There are no statistically significant differences between both groups regarding patients' characters. The tracts were successfully dilated in all patients. Statistical analyses show a significant difference (p ˂0.05) between both groups regarding the time of dilatation (sec) (68 ±15 Vs 147 ±18), time of X-ray exposure (sec) (during dilatation; 36 ±10 Vs 61 ±15 and the total; 157 ±16 Vs 181 ±20), hemoglobin loss (mg/dl) (0.7 ±0.2 Vs 1.2 ±0.3) and hospital stay (day) (3 ±0.6 Vs 3.7 ±0.7) with favorable results to OSD. Complication rates were comparable between the two groups.

CONCLUSIONS

One-shot dilatation is efficient as MTD during PCNL while patients in Barts flank-free modified supine position, with less dilatation time, X-ray exposure, blood loss, and hospital stay than MTD.

Comparison outcomes of percutaneous nephrolithotomy in prone and flank position in obese patients: A randomized clinical trial

BACKGROUND

The aim of this study was to compare the complications of percutaneous nephrolithotomy (PCNL) surgery in Flank and Prone positions in patients with a BMI above 30.

METHODS

In this randomized clinical trial patients were randomly assigned to PCNL treatment in one of two groups undergoing PCNL under fluoroscopic guidance in Flank or Prone positions. Patient demographic information, stone number, size and location, stent duration, hospital stay, blood loss, Creatinine, hemoglobin, hematocrit changes, and arterial blood gas changes and acid-base hemostasis were collected.

RESULTS

In this study, 60 patients were examined, which were divided into two groups of 29 people, prone and 31 people. Mean stone size was 3.16 ± 0.82 cm. arterial blood gases did not differ significantly between two groups. The SFR (stone free rate) in the prone and flank groups was 91.02% and 86.89%, respectively. However, SFR and Complications in the prone and flank groups were not significantly different (p value of 0.081 and 0.13, respectively).

CONCLUSIONS

According to the results of this study, PCNL complications and acid-base changes is not significantly different in flank and prone positions in obese patients. However, SFR is slightly lower in flank group. Thus, PCNL in flank position is not superior to prone position in obese Patients. It is recommended to choose each of these surgical methods according to the surgeon's facilities and skills.

Prone versus Barts “flank-free” modified supine percutaneous nephrolithotomy: a match-pair analysis

Background/aim

In this study, we aimed to compare the results of prone and Barts “flank-free” modified supine percutaneous nephrolithotomy (PCNL) operations in our clinic.

Materials and methods

The data from patients that underwent Barts “flank-free” modified supine PCNL (BS-PCNL) (n = 52) between June 2018 and July 2020 and prone PCNL (P-PCNL) (n = 286) between April 2014 and June 2018 were retrospectively evaluated. Of those 286 patients, 104 patients whose sex, age, body mass index, American Society of Anesthesiology score, stone localization, stone size, and hydronephrosis matched the BS-PCNL group in a 1:2 ratio were included in the study. The groups were compared in terms of intraoperative outcome, complication rates, and stone-free rates.

Results

The mean age of all patients (58 females, 98 males) included in the study was 41.8 ± 15.2 years, and the mean body mass index (BMI) was 24.7 ± 2.9 kg/m2. The mean operation time was significantly shorter in the BS-PCNL group than in the P-PCNL group (80.2 ± 15.1 min vs. 92.4 ± 22.7 min and p = 0.01). There was no significant difference between the two groups in terms of fluoroscopy time, intraoperative complications, postoperative complications, and stone-free rates.

Conclusion

Our study shows that BS-PCNL is an effective and safe method that significantly reduces the operation time and should be considered as one of the primary treatment options for patients scheduled for PCNL.

Management of upper calyceal stone by percutaneous nephrolithotomy through lower calyx access: prone versus supine position

Background

The best way in the management of calyceal stone by percutaneous nephrolithotomy (PCNL) is to go directly into the desired calyx. However, in upper calyx, this direct entry may be associated with undesired complications, and through lower calyx is limited in prone PCNL. Recently, there is another option about reaching it through the lower calyx in supine position with more accessibility and better manipulation. This study aimed to evaluate the management of the upper calyceal stone by PCNL through lower calyx access in prone versus supine position.

Methods

A total of 38 patients with upper calyceal stone (≥ 2 cm) were randomly divided into two groups; the first group included 18 patients managed by PCNL in the prone position, and the second group included 20 patients managed in supine position. All data of both procedures were collected and statistically analyzed to compare between both groups.

Results

There is no statistically significant difference between groups as regards demographic and stone characters. The angle between the access to the lower calyx and access of the upper calyx was significantly wider in the supine group versus prone group (130.2° ± 23.46° vs. 89.67° ± 14.56°, respectively). The mean operative and fluoroscopy time was significantly longer in the prone group. There is no significant difference in intraoperative or postoperative morbidity. The stone-free rate was significantly higher in the supine group than the prone group (85% vs 38.9%, respectively). Also stone approachability was higher in the supine group than prone group (95% vs. 66.7%, respectively).

Conclusion

Management of upper calyceal stone by PCNL through the lower calyx is safe, but it is more effective in the supine position than in prone position.

Supine versus prone PCNL in lower calyceal stone: Comparative study in a tertiary care center

INTRODUCTION

Renal calculus disease is an age old disease of human being. PCNL (Percutaneous nephrolithotomy) stands as a gold standard treatment for large renal calculus which is traditionally being done in prone position.

OBJECTIVE

To evaluate the safety and efficacy of supine PCNL versus prone PCNL comparing intraoperative time, requirement of relook PCNL, post op hemoglobin drop, post operative hospital stay, post operative complication, SFR ( stone free rate).

METHODS AND MATERIALS

It is a prospective study done in Urology department in a tertiary care center in Eastern India between October 2017 and October 2018. A total of 84 patients with lower calyceal renal stones underwent PCNL, 42 of them in supine and 42 in prone position. Lower calyceal stone, size measuring 1 to 2 cm were included in the study.

RESULTS

The mean intra operative time was 91.76 min in supine group and 85.43 min in prone group with a p value of 0.115. The mean hemoglobin drop was 1.11 g/dl and 1.18 g/dl in supine and prone position, respectively (p value 0.75). The mean post operative hospital stay was 4.1 and 3.86 days in supine and prone group (p value 0.58), respectively. Two patients in each group require relook PCNL. Stone free rate at 1 month was 95.23% and 90.47% (p value 0.9), respectively in case of supine and prone group.

CONCLUSION

Supine PCNL is feasible, comparable to prone PCNL in respect to operative parameters with relatively higher stone free rate though statistically insignificant.

Prone versus supine percutaneous nephrolithotomy: a systematic review and meta-analysis of current literature

INTRODUCTION

Percutaneous nephrolithotomy (PNL) can be performed either in prone or supine position. This study aimed at gathering together randomized controlled trials (RCTs) comparing efficacy and safety between prone and supine PNL.

EVIDENCE ACQUISITION

Systematic review of literature was conducted using the Scopus, Medline and Web of Science databases. Study selection, data extraction and quality assessment were independently assessed by two authors. Meta-analysis was performed with Review Manager 5.3. Sensitivity analyses were performed to exclude studies with high risk of bias.

EVIDENCE SYNTHESIS

Pooled data from 12 studies including 1290 patients were available for analysis. Only one study was found to have overall low risk of bias. Significantly shorter operative time was found in favor of supine PNL (mean difference 13 minutes, 95% confidence interval [CI]: 3.4-22.7; P<0.01). Stone-free rate (SFR)≥14 days after surgery was significantly higher in prone PNL (odds ratio [OR]=2.15, 95% CI: 1.07-4.34; P=0.03). Significantly higher fever rate was found in prone PNL (OR=1.60, 95% CI: 1.03-2.47; P=0.04). Overall SFR, hospital stay length, complications rate, transfusions rate and blood loss, as well as non-lower calyx puncture rate, puncture attempts and tubeless intervention rate did not differ between prone and supine PNL (P>0.05).

CONCLUSIONS

Efficacy of PNL seems balanced between prone and supine position, with comparable overall SFR and shorter operative time in favor of supine PNL. Safety of PNL appears in favor of supine PNL, with lower fever rate. Because of study heterogeneity and possible risks of outcome bias, results from this study should be interpreted with caution. Altogether, both prone and supine PNL account for appropriate therapy options.

Split-leg modified lateral versus prone position in percutaneous nephrolithotomy: a prospective, randomized trial

PURPOSE

Standard prone position (PP) during percutaneous nephrolithotomy (PNL) has multiple drawbacks. We aimed to compare PNLs performed in split-leg (SL) modified lateral position (MLP) and those performed in standard PP.

METHODS

A prospective, randomized, unblind, double arm trial was conducted at a tertiary care academic medical center in Egypt, between November 2017 and October 2019. Adult patients with renal stones undergoing PNL were included. According to renal anatomy and stone complexity, stratified randomization was performed and study participants were allocated into either SL-MLP group or PP group. The stone free rate (SFR), total operative time, track formation time, fluoroscopy time, auxiliary procedures, and complications were compared.

RESULTS

There were 61 patients in SL-MLP group and 63 patients in PP group. Both groups had similar baseline characteristics. The SFR was comparable between groups: 75.4% in SL-MLP group and 77.8% in PP group (p = 0.755). The mean total operative time was shorter and mean track formation time was longer in SL-MLP group (55.33 ± 20.73 vs. 98.49 ± 9.23, p < 0.001 and 7.89 ± 3.68 vs. 6.52 ± 1.77, p = 0.002). There was no significant difference in fluoroscopy time, total complication rates, hemoglobin reduction and need for blood transfusion between the groups. In SL-MLP group, all PNL procedures as well all the associated procedures were performed with the patients in the same position.

CONCLUSION

SL-MLP PNL has a short operative time and similar SFR and complication rate compared to PP PNL. SL-MLP allowed antegrade and retrograde access to the urinary tract without patient repositioning.

The risk factors associated with colonic injury during percutaneous renal stone surgery – a literature review

Objective:

A focused literature review was conducted of colonic injuries occurring during percutaneous nephrolithotomy (PCNL) procedures to determine the importance of patient position, identifiable risk factors and methods to avoid colonic injury.

Method:

A MEDLINE literature search was performed from PubMed and Scopus databases to retrieve all articles relating to colonic injuries occurring during PCNL. Incidence of colonic injury, patient management, position, side of stone and recognised risk factors were compiled for analysis.

Results:

Of the 35,054 PCNLs carried out, 87 colonic perforations were identified, which results in a 0.25% chance of perforation. A total of 65.5% (57/87) of colonic perforations occurred during left-hand punctures, and 54.0% (47/87) occurred in the prone position. Retrorenal colon, posterior colon, previous renal tract surgery, horseshoe kidney and mobile kidneys were the most common risk factors identified.

Discussion:

The risk of colonic perforation during PCNL was 0.25% across these studies. It more commonly occurred in the prone position and on the left-hand side. Only four perforations were noted to be in the supine position. A retrorenal colon is implicated as the most common identifiable risk factor. Careful preoperative work-up, planning and intraoperative use of ultrasound combined with fluoroscopy is the best method of preventing a colonic injury.

Level of evidence:

Not applicable for this multicentre audit.

Supine percutaneous nephrolithotomy: tips and tricks

This paper aims to give an exhaustive overview of supine percutaneous nephrolithotomy (PCNL) illustrating some tips and tricks in order to optimize its execution in full safety. Critical review of Pros and cons of supine PCNL is accomplished to allow the urologist to experience the beauty of this position while being ready to overcome its minimal shortcomings.

Prone versus modified supine percutaneous nephrolithotomy: which is more cost effective in an Australian tertiary teaching hospital?

Introduction:

Percutaneous nephrolithotomy is currently one of the main treatment options for large renal stones, but the effect of positioning on comparative costing has been scarcely documented. We aimed to compare the cost effectiveness of modified supine with traditional prone percutaneous nephrolithotomy procedures in the context of Victoria, Australia.

Materials and methods:

A prospective group of 236 renal units (224 patients) was included in the two-site study, with 76 performed in the prone position and 160 performed in the modified supine position. Costing was calculated using a ‘bottom-up’, all-inclusive framework that generates per-hour costs for theatre, recovery unit and ward costs from base costs and maintenance costs. Percutaneous nephrolithotomy-specific equipment was added to calculate comparative costs of modified supine versus prone procedures. Chi squared and T tests were used for statistical analysis.

Results:

There was a significant difference in the overall costing between the modified supine and prone groups. The modified supine group had a lower total cost (AUD$6424.29) compared to the prone group (AUD$7494.79) ( P=0.007), lower operative costs (AUD$4250.93 vs. AUD$5084.29, P=0.002) and lower ward costs (AUD$533.55 vs. AUD$1130.20, P<0.001). There was no significant difference in recovery times in the modified supine and prone groups, although the modified supine group appeared to have shorter recovery times (AUD$690.69 vs. AUD$586.05, P=0.209).

Conclusions:

Modified supine percutaneous nephrolithotomy has significantly lower total costs, operative costs and ward costs compared to prone percutaneous nephrolithotomy. Larger randomised trials are needed to assess these findings further. Level of evidence: Not applicable for this multicentre audit.

Comparison of supine and prone miniaturized percutaneous nephrolithotomy in the treatment of lower pole, middle pole and renal pelvic stones: A matched pair analysis

Purpose

We aimed to compare the outcomes of supine and prone miniaturized percutaneous nephrolithotomy (m-PNL) in the treatment of lower pole, middle pole and renal pelvic stones.

Materials and Methods

54 patients who performed supine m-PNL between January 2017 and March 2018 and 498 patients who performed prone m-PNL between April 2015 and January 2018 were included in the study. Of the 498 patients, 108 matching 1: 2 in terms of age, gender, body mass index, American Association of Anesthesiology score, stone size, stone localization and hydronephrosis according to the supine m-PNL group were selected as prone m-PNL group. The patients with solitary kidney, upper pole stone, urinary system anomaly or skeletal malformation and pediatric patients (<18 years old) were excluded from the study. The success was defined as ‘complete stone clearance’ and was determined according to the 1^st month computed tomography.

Results

The operation time and fluoroscopy time in supine m-PNL was significantly shorter than prone m-PNL group (58.1±45.9 vs. 80.1±40.0 min and 3.0±1.7 min vs. 4.9±4.5 min, p=0.025 and p=0.01, respectively). When post-operative complications were compared according to the modified Clavien-Dindo classification, overall and subgroup complication rates were comparable between groups. There was no significant difference between the groups in terms of the success rates (supine m-PNL; 72.2%, prone m-PNL; 71.3%, p=0.902).

Conclusions

Supine m-PNL procedure is more advantageous in terms of operation time and fluoroscopy time in the treatment of lower pole, middle pole and renal pelvic stones.

Techniques for fluoroscopy-guided percutaneous renal access: An analytical review

Percutaneous renal access is a key step for a successful percutaneous nephrolithotomy. It involves the use of fluoroscopy, ultrasonography, or a combination of both. Over the years, various techniques have been proposed for fluoroscopy-guided access, and this article reviews the different techniques along with the anatomical principles for fluoroscopy-guided percutaneous renal access. A literature search was performed using "PubMed" for relevant literature describing the various techniques for fluoroscopy-guided percutaneous renal access. Each technique was analyzed in regard to how it describes selecting the skin site for puncture and determines the angle and depth of puncture. The advantages, limitations, and variations of these techniques were also studied. Each technique has its advantages and limitations. No study has compared all the techniques either in vivo or in vitro. Only a comparative study would establish the superiority of one technique over the other. Until this is done, endourologists should be well versed with the existing techniques.

Updates in endourological management of urolithiasis

Urinary stone disease, or urolithiasis, is a very common disease with increasing prevalence and incidence. With the advancement of endoscopic techniques, the treatment outcomes of ureteroscopy (or transureteral lithotripsy) and percutaneous nephrolithotomy are continuously improving. In recent years, there have been many new developments in the field, including new endoscopy design, more effective auxiliary tools, improvement in treatment protocols, introduction of robotic technology, combining both ureteroscopy and percutaneous nephrolithotomy (endoscopic combined intrarenal surgery or transureteral lithotripsy-assisted percutaneous nephrolithotomy), improvement in laser technology, and so on. All these new inputs will further improve the treatment efficacy and safety of the procedures, thus benefiting our patients. In the present review, we briefly go through the main steps of ureteroscopy and percutaneous nephrolithotomy, with a concise description and application of these new advances.

Patient positioning during percutaneous nephrolithotomy: what is the current best practice?

Percutaneous nephrolithotomy (PCNL) is the gold standard procedure for treatment of large stones and complex kidney disorders, but its morbidity remains the highest among stone treatment procedures. In pursuit of minimizing complication rates, surgeons have developed different variations of the classic prone position in which PCNL is usually performed; one among them is supine position. In this study, we review the literature and present all available evidence on different variations in positioning during PCNL, in an effort to identify if there is a position that can minimize the morbidity of this procedure.

A retrospective, observational study of supine percutaneous nephrolithotomy

Objective:

The objective of this study is to assess stone clearance and perioperative complication rates of supine percutaneous nephrolithotomy (PCNL).

Methods:

This was a retrospective, observational study of supine PCNL performed in a surgical unit at a district general hospital by two surgeons in the United Kingdom. Data collected included patient demographics, comorbidities, complexity of renal calculi, perioperative complications and stone clearance rates.

Results:

A total of 112 supine PCNL procedures were observed in this study. The mean (SD) American Society of Anesthesiologists (ASA) grade and Guy’s Stone Score were 2.0 (0.75) and 2.3 (1.06) respectively. The median (interquartile range (IQR)) duration of in-patient admission was four (one) nights. Complete stone clearance was achieved in 74 (67.3%) of the procedures, while more than 90% clearance of the renal stone burden was achieved in a further eight (7.3%). The most common perioperative complications recorded were blood loss requiring blood transfusion (three (2.7%)) and postoperative fever (two (1.8%)).

Conclusion:

This case series shows that supine PCNL can lead to good stone clearance and low complication rates.

Total tubeless ultra-mini supine percutaneous nephrolithotomy: A feasibility study

OBJECTIVE

The ultra-mini percutaneous nephrolithotomy (PCNL) for treating low-volume renal nephrolithiasis is being used as an alternative modality to the conventional PCNL. However its use in the supine position has been scarcely reported.

MATERIAL AND METHODS

Patients who underwent ultra-mini PCNL in the supine position within the time frame of January 2017 to July 2017 were studied. All these patients had this as their first-line treatment. The patients had calculus limited to either a single calyx or just extending to the pelvis and the stone size was less than 2 cm in its maximal dimension. An 8.5 Fr operating nephroscope was used. The patients were positioned in the Galdakao modified Valdivia supine position. The stones were fragmented using Holmium-YAG laser. Various surgical outcomes including duration of the surgery, stone-free rate and any subsequent complications-if any-were analyzed.

RESULTS

The study includes a series of 14 patients with 15 renal units (one patient treated with bilateral renal stone disease). The mean age of the patients was 39.07 years and body mass index was 25.5 kg/m². Intrarenal stone location was as follows: lower calyx, n=8; middle calyx, n=3, upper calyx, n=1, and pelvis, n=3. Median operative time was 52.66 min (range: 40-70) and the stone-free rate was 93.3%. Only one patient had residual fragments and needed subsequent extracorporeal shock wave lithotripsy.

CONCLUSION

Ultra-mini PCNL in supine position with a complete tubeless approach for renal stone disease is a safe method for treating low-volume disease. Studies with a larger cohort may be required to finally validate this technique.

Lateral percutaneous nephrolithotomy: A safe and effective surgical approach

Introduction:

Percutaneous nephrolithotomy (PCNL) is traditionally performed with the patient in the prone position for large renal calculi. However, anesthetic limitations exist with the prone position. Similarly, the supine position is associated with poorer ergonomics due to the awkward downward position of the renal tract, a smaller window for percutaneous puncture, and a higher risk of anterior calyx puncture. This study aimed to demonstrate the feasibility and safety of lateral-PCNL in managing large renal calculi without the disadvantages of prone and supine positions.

Methods:

Retrospectively, 347 lateral-PCNL cases performed from July 2001 to July 2015 were examined. the patient's thorax, abdomen, and pelvis were positioned over a bridge perpendicular to a “broken” table, creating an extended lumbodorsal space. The procedure was evaluated in terms of stone clearance at 3 months’ postprocedure, operative time, and complications.

Results:

Primary stone clearance was achieved in 82.7% of patients. The mean operating time was 97 min. The average time taken to establish the tract and mean radiation time were 4.5 min and 6.93 min, respectively. In total, 2.3% of patients required postoperative transfusion, and 13.5% of patients had postoperative fever. There was one case of hydrothorax, but no bowel perforation.

Conclusions:

Our lateral-PCNL technique allows for effective stone clearance due to good stone ergonomics and it should be considered as a safe alternative even in the most routine procedures.

Invited review: the tale of ECIRS (Endoscopic Combined IntraRenal Surgery) in the Galdakao-modified supine Valdivia position

Modern-day percutaneous nephrolithotomy (PNL) has undergone considerable evolution, mainly driven by the improvement in access techniques, endoscopic instrumentation technology, lithotripsy devices and drainage management. The introduction of the supine and supine-modified positions is also part of this evolution, enabling comfortable and safe procedures from an anaesthesiological point of view, and an easy combined retrograde surgery [Endoscopic Combined IntraRenal Surgery (ECIRS)], allowing tailoring of the procedure on the patient, the dynamic anatomy of the collecting system and the urolithiasis. The conceptual value of ECIRS extends beyond the single diagnostic and active advantages due to the simultaneous contribution of the flexible retrograde ureteroscopy: the merit consists in the promotion of the versatile attitude of the urologist, and in the fulfillment of a personalized stone management. ECIRS has no pretensions of superiority, but for sure is a new safe and effective way of interpreting PNL, in the hands of an experienced surgical team.

Mini PCNL for renal calculi: does size matter?

OBJECTIVE

To evaluate the minimally invasive percutaneous nephrolithotomy (MIP) system for renal calculi.

PATIENTS AND METHODS

Consecutive patients undergoing mini-percutaneous nephrolithotomy (mPCNL) procedures with the MIP system were enrolled. Patient position, American Society of Anesthesiologists classification, puncture location, stone clearance, postoperative drainage and complications were recorded, and features unique to MIP were noted.

RESULTS

In all, 30 patients underwent 32 mPCNL procedures. The mean stone size was 17 (10.75-21.25) mm and the mean number of stones was 1 (1-2). The median stone clearance rate was 96.5 (95-100)%. The complication rate was 9.3%. No patient required a transfusion. In addition to these outcomes, we noted that the MIP system has many advantages over conventional PCNL (cPCNL). It is easy to learn and can be performed in both supine and prone positions. It is safe for supracostal puncture, provides excellent access to nearly all calyces and upper ureter, has multiple stone treatment options, can be used as an adjunct to cPCNL, and can be performed as a tubeless procedure.

CONCLUSION

Our experience with the MIP system has shown several advantages over cPCNL. mPCNL with the MIP system has several features that suggest it should be considered as an alternative or adjunct to cPCNL, ureteroscopy and extracorporeal shockwave lithotripsy.

Prone Versus Supine Percutaneous Nephrolithotomy: What Is Your Position?

PURPOSE OF REVIEW

Percutaneous nephrolithotomy (PCNL) is the gold standard surgical procedure for treating large, complex renal stones. Due to its challenging nature, PCNL has undergone many modifications in surgical technique, instruments, and also in patient positioning. Since the first inception of PCNL, prone position has been traditionally used. However, alternative positions have been proposed and assessed over the years. This is a comprehensive review on the latest developments related to positioning in the practice of PCNL.

RECENT FINDINGS

The prone position and its modifications are the most widely used positions for PCNL, but with the introduction of various supine positions, the optimal position has been up for debate. Recent meta-analysis has shown a superior stone-free rate in the prone position and comparable complication rates to the supine position. The advantage of ease of access to the urethra for simultaneous retrograde techniques in the supine position is also possible with modifications in the prone position such as the split-leg technique. Modern-day PCNL has transformed from an operation traditionally undertaken in the prone position to a procedure in which a prone or supine position may be employed; however, published data have not shown significant superiority of either approach.

Percutaneous nephrolithotomy in complete supine flank-free position in comparison to prone position: A single-centre experience

OBJECTIVES

To assess the outcomes of performing percutaneous nephrolithotomy (PCNL) in a modified supine position, more feasible for surgeons, anaesthetists, and operating theatre staff, as well as for the patient himself, and evaluating it in comparison to the standard prone position.

PATIENT AND METHODS

A retrospective, case-control study was conducted between January 2011 and December 2015. In all, 197 patient's records were reviewed. The initial 101 patients were operated upon in prone position. From mid-2013, 96 patients were operated upon in a complete supine, flank-free position. The groups were compared in terms of operation time, calculated from positioning the patient after anaesthesia induction, insertion of ureteric catheter, puncture of renal system, until the end of procedure; stone-free rate; hospital stay; and postoperative complications, such as transfusion rate, fever, and urinary leakage.

RESULTS

There were two significant differences between the groups. Firstly, the operation time was a mean (SD) 32.3 (6.6) min shorter for the supine versus the prone position (P < 0.001). Secondly, hospital stay was a mean (SD) 1.2 (0.75) days shorter for the supine vs the prone position (P < 0.001). The complete stone clearance rate (85.4% for supine vs 79.2% for prone; P = 0.2) and postoperative complications (7.3% for supine vs 17.8% for prone; P = 0.02) were comparable in both groups.

CONCLUSION

Supine PCNL is a feasible procedure with similar outcomes in terms of stone-free rate as well as postoperative complications, to the standard prone PCNL. It reduces unnecessary delay that occurs during change of position resulting in significant shortening of the total operation time and surgeons can perform supine PCNL whilst sitting.

Can We Use Single-step Dilation as a Safe Alternative Dilation Method in Percutaneous Nephrolithotomy?

OBJECTIVE

To examine the outcomes of the patients who underwent percutaneous nephrolithotomy with single-step dilatation technique in our clinic.

MATERIALS AND METHODS

A total of 932 patients who underwent percutaneous nephrolithotomy by using single-step dilation technique in the period between 2008 and 2015 in our clinic were included in the study. Data of the patients were analyzed, such as age, sex, stone burden, operative time, fluoroscopy time, operation success, and perioperative and postoperative complications.

RESULTS

An analysis of the data of 932 patients revealed similar operation success and complication rates as in the literature. Mean age of the patients included in the study was 48.9 years. Mean operative time was 66.6 minutes and mean fluoroscopy time was 139 seconds. Postoperative residual stone was detected in 17.1% of the patients. Postoperative fever was observed in 29 patients (3.1%), and sepsis developed in 11 (1.1%) of them. Additional postoperative procedures were required in 29 patients (3.1%). No patient was lost due to complications. Our data were compatible with the literature.

CONCLUSION

Single-step dilation technique can be used as an effective and safe alternative dilation method in adult patients.

Positioning for percutaneous nephrolithotomy

PURPOSE OF THE REVIEW

To highlight the progressive evolution of the issue of patient positioning for percutaneous nephrolithotomy (PNL), explain the history of the prone and supine positions, report respective advantages and drawbacks, critically interpret the past and current literature supporting such arguments, identify the best candidates for each position, and reflect on the future evolution of the two approaches.

RECENT FINDINGS

Positioning for PNL has become a matter of debate during the last decade. The traditional prone PNL position - most widely performed with good success and few complications, and exhibiting essentially no limits except for the treatment of pelvic kidneys - is nowadays flanked mainly by the supine and supine-modified positions, equally effective and probably safer from an anesthesiological point of view. Of course, both approaches have a number of advantages and drawbacks, accurately reported and critically sieved.

SUMMARY

The current challenge for endourologists is to be able to perform PNL in both prone and supine positions to perfectly tailor the procedure on any patient with any stone burden, including increasingly challenging cases and medically high-risk patients, according to the patient's best interest. Intensive training and experience is especially needed for supine PNL, still less popular and underperformed worldwide.

VIDEO ABSTRACT

http://links.lww.com/COU/A8.

Modified supine versus prone percutaneous nephrolithotomy: Surgical outcomes from a tertiary teaching hospital

Purpose

The traditional prone positioning of percutaneous nephrolithotomy (PCNL) is associated with various anesthetic and logistic difficulties. We aimed to compare the surgical outcomes of PCNLs performed using our modified supine position with those performed in the standard prone position.

Materials and Methods

A prospective group of 236 renal units (224 patients) undergoing PCNL were included in this 2 site study: 160 were performed in the modified supine position were compared with 76 undergoing PCNL in the prone position. The outcomes of radiation dose, radiation time, stone free rate, body mass index (BMI), stone size, operative time, length of stay (LOS), in hospital and complications were compared. Chi-square and t-tests were used.

Results

There were no significant differences in mean radiation time, radiation dose or stone size between the modified supine and prone groups. The supine group had a higher mean BMI (31 kg/m² vs. 28 kg/m², p=0.03), shorter mean surgical time (93 minutes vs. 123 minutes, p<0.001), shorter mean LOS (2 days vs. 3 days, p=0.005) and higher stone free rate (70% vs. 50%, p=0.005). There were no differences in septic or bleeding complications but the prone group had a higher rate of overall complications.

Conclusions

Modified supine PCNL has significantly lower operative time, shorter LOS and higher stone-free rate compared with prone in our series, while remaining a safe procedure.