The Debate Over Percutaneous Nephrolithotomy Positioning: A Comprehensive Review

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.

Supine versus prone percutaneous nephrolithotomy in management of patient with complex renal stone diseases

OBJECTIVES

Compare the surgical outcomes, safety, stone free rate, hospital stay, and complication of prone and supine PCNL in case of complex renal stone.

MATERIALS AND METHODS

This is an observational study conducted in our institute, it consist of 120 patients over the period of 2 years from July 2021 to June 2023, all the patients were divided into two groups: 60 patients underwent modified supine percutaneous nephrolithotomy (PCNL) and remaining 60 patients underwent standard prone PCNL. The measured data included operative time, number of punctures, blood loss, stone-free rate, length of hospital stays, and rate of complications.

RESULTS

The two groups were comparable in mean age, male to female ratio, number of punctures, number of tract, size of tract, residual calculi in follow up period, blood transfusion, re-do surgery, chest complication, hospital stay, and postoperative fever and pain. The mean operating time was 1.59 h in supine PCNL and 2.49 h in prone PCNL. The p value was significant (p = 0.001).

CONCLUSIONS

By this study we observed that the supine PCNL is associated with statistically significant reduced operating time as compared to conventional prone PCNL with advantages of not putting the patient in prone position. The postoperative complications such as pain and fever were not significant when compared in both groups. We conclude our study and found that, the supine PCNL is an equally effective in treating complex renal stone as compared to prone PCNL.

Flank free modified supine versus prone ultra mini percutaneous nephrolithotomy in treatment of medium sized renal pelvic stone a randomized clinical trial

INTRODUCTION & OBJECTIVES

percutaneous nephrolithotomy (PNL) is the standard treatment of renal stone more than 2 cm. ultra-mini-percutaneous nephrolithotomy had emerged in the last decade as a new technique in treating renal stones less than 2 cm. in this study we compare between outcomes of (UMP) in modified flank free supine (FFSP), and prone position.

MATERIALS & METHODS

A prospective randomized study was conducted between January 2016 and April 2020, including 122 patients, divided into two matched groups. Group A included 61 patients who underwent UMP in FFSP, and group B included 61 patients who underwent UMP in a prone position. All patients had a single renal pelvic stone 1-2 cm. Patients with a single kidney, renal anomalies, BMI≥40, history of ipsilateral renal surgery, and age less than 18 years were excluded. In both groups, the dilatation was done up to 13 f; a holmium laser was used through a 9f ureteroscope for fragmentation. Nephrostomy tube and ureteric stent were used only when indicated.

RESULTS

122 patients who divided into two groups. The mean age was 40.09±13.63 and 39.67±13.80 years in both groups, respectively. The operative time was 63.64±9.22 and 78.48±9.55 minutes in groups A &B, respectively (P=0.0001). The fluoroscopy time was 3.47±0.56 and 4.45±0.39 minutes in groups A &B, respectively (P=0.0001).no significant difference between both groups regarding operative and post-operative complications. Shift to miniPNL was needed in one patient in group A and four patients in group B due to impaired vision. The hospital stay was 25.36±4.23 and 26.13±4.76 hours in both groups, respectively. The initial stone-free rate was 95.1% and 91.8% in both groups, respectively.

CONCLUSIONS

ultra-mini-percutaneous nephrolithotomy in modified supine position shows comparable results to the prone position regarding stone-free rate, hospital stay, and perioperative complication, with significantly shorter operative and fluoroscopy time.

Comparison of the Prone Split-Leg Position with the Traditional Prone Position in Percutaneous Nephrolithotomy: A Propensity Score-Matching Study

Background and Objective: Several positions have been described for percutaneous nephrolithotomy (PCNL). The aim of this study was to compare the safety and effectiveness of the traditional prone position PCNL (TP-PCNL) and the prone split-leg position PCNL (PSL-PCNL). Patients and Methods: A retrospective review was made of the data of 212 patients who underwent prone PCNL in PSL or TP between January 2017 and November 2019. The demographic and preoperative clinical data were used for propensity score-matching (PSM). Following the PSM based on a multivariable logistic regression model, the PSL-PCNL and TP-PCNL groups were compared in preoperative, perioperative, and postoperative parameters. All surgical procedures were performed by an experienced endourologist. Results: After PSM, 51 patients from the PSL-PCNL group were matched to 51 TP-PCNL patients. The stone burden was not statistically significant between the two groups (p = 0.388). The mean operation time of the two groups was significantly different (81.5 ± 32.4 minutes vs 93.1 ± 25.9 minutes, respectively, p = 0.026). The hemoglobin decrease in the PSL-PCNL group was greater than that in the TP-PCNL group (-17.7 ± 16.9 g/L vs 13.1 ± 10.9 g/L, p < 0.001). Both groups had similar stone-free rates after 2 weeks (p = 0.49). No significant difference was observed between the groups in the total complication rate (p = 1). Conclusions: The application of PSL in PCNL simplifies the surgical procedure and shortens the operating time. Another important advantage is that it allows retrograde intrarenal surgery and ureteroscopy to be performed simultaneously. We recommend the PSL to be applied in PCNL for renal stone patients.

The impact of anterior calyceal stones on the outcomes of percutaneous nephrolithotomy for complex kidney stones: a comparative study

BACKGROUND

This study aimed to evaluate the possible effect of anterior calyceal stones on the surgical outcomes of percutaneous nephrolithotomy.

METHODS

Consecutive patients with complex kidney stones from 2012 to 2020 were evaluated retrospectively. In total, 219 patients were divided into 2 groups based on the presence of anterior calyceal stones (group 1; N.=89) or not (group 2; N.=130). The groups were compared in terms of surgical outcomes (i.e., stone-free rate [SFR], operation time, and hemoglobin drop) and complications.

RESULTS

The patient demographics and stone characteristics were similar between the groups. Multiple access was more frequently done in group 1 than it was in group 2 (47.2% vs. 30.8%; P=0.014), and the SFR was lower in group 1 (51.7%) than it was in group 2 (67.7%; P=0.017). Of the anterior calyceal stones in group 1, 42.6% could not be cleaned. However, when excluding patients who have only anterior residual stones from the statistical analysis, the groups had similar SFRs (68.5% vs. 67.7% for group 1 and group 2, respectively).

CONCLUSIONS

The presence of complex kidney stones with anterior calyceal extension are associated with higher residual stones rates in the anterior calyx. Also, it increases multiple access, the operation time, and level of hemoglobin drop.

Radiation exposure in prone vs. modified supine position during PCNL: Results with an anthropomorphic model

INTRODUCTION

Radiation exposure during urological procedures is still of concern in the urology community. It has been reported that percutaneous nephrolithotomy (PCNL) in supine position has less irradiation, as the puncture is mostly done under ultrasound guidance. However, it can also be done under fluoroscopy guidance. Unfortunately, data on radiation exposure during PCNL is lacking since they are often drawn from generalization and extrapolation, or they do not evaluate new procedures or different positions. The aim of our study was to compare the radiation dose depending on the position of the surgeon during PCNL.

METHODS

A portable C-arm was used in standard mode (32 impulsions/second; 98 kV, 3.8 mA). Specific dosimeters were placed for lens, extremity, and torso. Anthropomorphic models and hand phantom models were used to reproduce the position of surgeon and patient (with same bone density as human) during PCNL in prone and modified supine position. Fluoroscopy time (FT) was six minutes to obtain higher exploitable signal, and the results are given for a FT of three minutes (more realistic). Ten percent of the FT is done with an angulation of 15 degrees and the rest in anteroposterior position.

RESULTS

The equivalent doses (ED) are given in uSV (uncertainty k=2). During the modified supine position: neck, lens, right index finger, left thumb, and index finger received EDs of 99 (20%), 62 (18%), 437 (10%), 112 (12%), and 204 (10%), respectively. In a prone position, the phantom received ED on the neck, lens, right thumb and index finger, left thumb and index finger of 85 (20%), 92 (12%), 401 (10%), 585 (10%), 295 (10%), and 567 (10%), respectively. In both positions, the right hand seems more exposed than the left hand.

CONCLUSIONS

The effective dose is 1.5- and 1.3-fold higher for lens and extremities, respectively, in prone position PCNL compared to modified supine position. Both positions are still well below the recommended limit for professional exposure.

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.

Impact of patient position on the outcomes of percutaneous neprolithotomy for complex kidney stones

Purpose:

To evaluate the impact of the patient position on the outcomes of PCNL among patients with complex renal stones.

Material and Methods:

From July 2011 to July 2014, we collected prospective data of consecutive patients who underwent PCNL. We included all patients with complex stones (Guy's Stone Score 3 or 4 (GSS) based on a CT scan) and divided them based on the position used during PCNL (prone or supine). The variables analyzed were gender, age, body mass index, ASA score, stone diameter, GSS, number of punctures, calyx puncture site, intercostal access and patient positioning. Complications were graded according to the modified-Clavien Classification. Success was considered if fragments ≤ 4mm were observed on the first postoperative day CT scan.

Results:

We analyzed 240 (46.4%) of 517 PCNL performed during the study period that were classified as GGS 3-4. Regarding patient positions, 21.2% were prone and 79.8% were supine. Both groups were comparable, although intercostal access was more common in prone cases (25.5% vs 10.5%; p=0.01). The success rates, complications, blood transfusions and surgical times were similar for both groups; however, there were significantly more visceral injuries (10.3% vs 2.6%; p=0.046) and sepsis (7.8% vs 2.1%; p=0.042) in prone cases.

Conclusion:

Supine or prone position were equally suitable for PCNL with complex stones and did not impact the success rates. However, supine position was associated with fewer sepsis cases and visceral injuries.

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.

Prone Percutaneous Nephrolithotomy: Does Bolster Orientation Matter?

OBJECTIVE

To assess whether horizontal vs vertical bolster orientation affects kidney position during prone percutaneous nephrolithotomy as this could impact the need for supracostal access and therefore the likelihood of pleural injury.

MATERIALS AND METHODS

In a prospective trial, 10 subjects with 20 renal units underwent magnetic resonance imaging in prone position with standard cylindrical bolsters oriented vertically and then horizontally. Vertical bolsters were placed along the lateral aspect of the chest. Horizontal bolsters were placed at the xiphoid and symphysis pubis. The position of the kidney relative to the pleura was assessed by measuring distances from the kidney upper pole to diaphragm, to the top of the first lumbar vertebra, and inferior-most rib. Nephrostomy tract length and tract proximity to adjacent organs were also measured.

RESULTS

Right and left kidney-to-diaphragm distance significantly increased with horizontal vs vertical bolsters by 3.44 cm and 1.86 cm, respectively (P = .02, P = .01). Right kidney-to-rib distance significantly increased by 2.4 cm (P = .025); left kidney-to-rib distance increased by 0.5 cm (P = .123). Right kidney-to-vertebral distance significantly increased by 2.16 cm (P = .007); left kidney-to-vertebral distance increased by 0.9 cm (P = .059). There was no significant difference in maximum access angle, overall tract length, or colon position between horizontal and vertical bolsters.

CONCLUSION

Orienting bolsters horizontally results in caudal kidney displacement without affecting access angle, overall tract length, or colon position. In comparison with vertical orientation, this may improve safety of percutaneous nephrolithotomy by decreasing the need for supracostal access and increasing the safety of supracostal access when required.

Contemporary Trends in Utilization and Perioperative Outcomes of Percutaneous Nephrolithotomy in the United States from 2003 to 2014

PURPOSE

To investigate the contemporary trends and perioperative outcomes of percutaneous nephrolithotomy (PCNL) by using a population-based cohort.

MATERIALS AND METHODS

Using the Premier Healthcare Database, we identified 225,321 patients in whom kidney/ureteral calculi were diagnosed and who underwent PCNL at 447 different hospitals across the United States from 2003 to 2014. Outcomes included 90-day postoperative complications (as classified by the Clavien-Dindo system), prolonged hospital length of stay, operating room time, blood transfusions, and direct hospital costs. Temporal trends were quantified by estimated annual percentage change (EAPC) by using least-squares linear regression analysis. Multivariable logistic regression was performed to identify predictors of outcomes.

RESULTS

PCNL utilization rates initially increased from 6.7% (2003) to 8.9% (2008) (EAPC: +5.60%, p = 0.02), before plateauing at 9.0% (2008-2011), and finally declining to 7.2% in 2014 (EAPC: -4.37%, p = 0.02). Overall (Clavien ≥1) and major complication (Clavien ≥3) rates rose significantly (EAPC: +12.2% and +16.4%, respectively, both p < 0.001). Overall/major complication and blood transfusion rates were 23.1%/4.8% and 3.3%, respectively. Median operating room time and 90-day costs were 221 minutes (interquartile range [IQR] 4) and $12,734 (IQR $9419), respectively. Significant predictors of overall complications include higher Charlson comorbidity index (CCI) (CCI ≥2: odds ratio [OR] 2.08, p < 0.001) and more recent year of surgery (2007-2010: OR 3.20, 2011-2014: OR 4.39, both p < 0.001). Higher surgeon volume was significantly associated with decreased overall (OR 0.992, p < 0.001) and major (OR 0.991, p = 0.01) complications.

CONCLUSIONS

Our contemporary analysis shows a decrease in the utilization of PCNL in recent years, along with an increase in complication rates. Numerous patient, hospital, and surgical characteristics affect complication rates.

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.

Conservative Management of Combined Pleural and Splenic Injury During Percutaneous Nephrostolithotomy

Splenic injuries related to percutaneous nephrostolithotomy (PCNL) are infrequent. Herein, we report a combined splenic and pleural injury incurred during PCNL along with radiographic images documenting the complication. A review of management techniques for similar injuries is included.

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.

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.

What is better in percutaneous nephrolithotomy - Prone or supine? A systematic review

OBJECTIVE

To review the literature reporting the technique of percutaneous nephrolithotomy (PCNL) and outcomes for prone and supine PCNL, as PCNL is an established treatment for renal calculi and both prone and supine PCNL have been described, but there has been much debate as to the optimal position for renal access in PCNL.

METHODS

A review of the medical literature was conducted using the PubMed database to identify relevant studies reporting on prone and supine PCNL published up until July 2015. Only publications in English were considered. Search terms included 'supine', 'prone', 'percutaneous nephrolithotomy', 'PCNL' and 'randomised controlled trial'. Articles relevant to the particular aspect of PCNL discussed were selected.

RESULTS

In all, 30 articles were included in the literature review. Nine of these articles were of Level 1 Evidence as graded by the Oxford System of Evidence-based Medicine.

CONCLUSION

The present systematic review highlights the benefits and disadvantages of supine and prone PCNL. The published data on supine and prone PCNL have shown no significant superiority of either approach. Whether prone or supine PCNL is optimal, remains a debatable topic.

The efficacy and safety of percutaneous nephrolithotomy under general versus regional anesthesia: a systematic review and meta-analysis

This meta-analysis was performed to evaluate the efficacy and safety of percutaneous nephrolithotomy (PCNL) under regional anesthesia (RA) vs. general anesthesia (GA). A systematic literature search in the electronic databases (Cochrane CENTRAL, Medline and EMBASE) was performed up to April 2014. Twelve trials, including 1954 patients, met the inclusion criteria and were included in the final analysis. Our pooled analysis showed that PCNL under RA could reduce surgical duration (MD, -2.47; 95 % CI, -3.51 to -1.44), hospitalization period (MD, -0.48; 95 % CI -0.93 to -0.04), fluoroscopy time (MD, -0.48; 95 % CI, -0.83 to -0.14), blood transfusion (OR, 0.59; 95 % CI, 0.38-0.92), postoperative pain (MD, -1.99; 95 % CI, -2.2 to -1.78), and analgesic requirements (MD, -19.14; 95 % CI, -26.64 to -11.63). However, there was no difference between RA and GA groups with regard to stone-free rate (OR, 1.09; 95 % CI, 0.86-1.37) and postoperative complications associated with PCNL (OR, 0.95; 95 % CI 0.58-1.54). Our results show that PCNL under RA offers several potential advantages over GA in terms of surgical duration, hospitalization period, fluoroscopy time, blood transfusion, postoperative pain, and analgesic requirements, but both anesthetic techniques appear to be equivalent with regard to the stone-free rate and complication rate. Along with the suggested favorable hemodynamic profile and lower cost, RA may prove a better alternative than GA.

Percutaneous nephrolithotomy in the oblique supine lithotomy position and prone position: a comparative study

OBJECTIVES

To compare the safety, efficacy, and complications of percutaneous nephrolithotomy (PCNL) in the oblique supine lithotomy position vs the prone position in a randomized comparative study.

PATIENTS AND METHODS

The study included 101 and 102 patients in the oblique supine lithotomy position and prone position, respectively. Inclusion criteria were renal and upper ureteral stones. Exclusion criteria were uncorrectable bleeding disorders, active urinary tract infection, and pregnancy.

RESULTS

Both the groups were comparable regarding the male/female ratio, stone size, and site. No significant differences were found in terms of the stone-free rate, blood transfusion rate, and complication rates. Significant differences were reported in mean hemoglobin loss (-1.03 and -2.18 g/dL), mean operative time (86.16 and 111.7 minutes), and mean hospital stay (49.88 and 81.2 hours) in the supine and prone positions, respectively, and anesthesiological parameters (the mean blood pressure decreased by 2 and 14.06 mm Hg, the mean heart rate changed by -0.82 and +13.28 beat/minute, and the peak air way pressure changed by +1.08 cm H2O and +7.56 cm H2O in the supine and prone positions, respectively).

CONCLUSIONS

PCNL in both positions was equally successful with no significant differences in complications. PCNL in the oblique supine lithotomy position was superior to PCNL in the prone position regarding operative time, hospital stay, and effects on respiratory and cardiovascular status, making it more comfortable for patients and anesthesiologists. Morbidly obese patients, patients with cardiologic disorders, and patients with pulmonary obstructive airway disease need further studies to show if they would benefit from these differences. Additionally, it is more comfortable for the surgeon with little challenges added in the initial puncture.

Is the supine position superior to the prone position for percutaneous nephrolithotomy (PCNL)?

The objective of this study is to update the two previous meta-analyses in order to evaluate the efficacy and safety of percutaneous nephrolithotomy (PCNL) for patients in the prone position versus supine position. An electronic database search of MEDLINE, EMBASE, google scholar, and the Cochrane library was performed up to June, 2013. All studies comparing prone with supine position for PCNL were included. The outcome measures were stone-free rate, operative time, complication and hospital stay. Two randomized controlled trials (RCTs) and 7 non-RCTs, including 6,413 patients (4,956 patients in the prone position group and 1,457 patients in the supine position group), met the inclusion criteria. Meta-analysis of extractable data showed that PCNL in the supine position was associated with a significantly shorter operative time (WMD: 21.7; 95% CI 2.46-40.94; p = 0.03) but lower stone-free rate (OR: 1.36; 95% CI 1.19-1.56; p < 0.0001) than PCNL in the prone position. There was no difference between the two positions regarding hospital stay (WMD = 0.05; 95% CI -0.16-0.25; p = 0.66) and complication rate (OR: 1.1; 95% CI 0.94-1.28; p = 0.24). In conclusion, the present study found different results from the two previous meta-analyses results regarding stone-free rate; PCNL in the supine position had a significantly lower stone-free rate than that in prone position.

Percutaneous nephrolithotomy: does position matter? - prone, supine and variations

PURPOSE OF REVIEW

The evolution of percutaneous renal stone surgery has recently seen an increasing number undergoing surgery in the supine position rather than just the classical prone technique. Several advantages have been proposed with the supine approach, including benefits for anaesthesia (cardiovascular and airway), the patient (reduced transfer-related injuries), and surgeon (combined retrograde and antegrade surgery, and ergonomics). As the supine technique and variations have now been practised for several years, it is timely to review whether it has been adopted universally and what factors may lead to preference for one approach over another.

RECENT FINDINGS

There have been several retrospective reports, but only two prospective randomized trials published in the literature, comparing the techniques. There have also been recent attempts at establishing national and international databases for percutaneous nephrolithotomy (PCNL) surgery to try and describe the practice patterns for this surgery, and also the factors that influence the decision to adopt a particular position. Although there appear to be no clear overall benefits for one position over another, and practice is likely to remain fairly surgeon-specific, there are some cases in which the supine PCNL may be preferable (e.g. in obese patients).

SUMMARY

Along with the development of centres offering this surgical technical variation, endourology training programmes will increasingly offer exposure to supine PCNL, which may then affect the global practice patterns.

Collecting system percutaneous access using real-time tracking sensors: first pig model in vivo experience

PURPOSE

Precise needle puncture of the renal collecting system is an essential but challenging step for successful percutaneous nephrolithotomy. We evaluated the efficiency of a new real-time electromagnetic tracking system for in vivo kidney puncture.

MATERIALS AND METHODS

Six anesthetized female pigs underwent ureterorenoscopy to place a catheter with an electromagnetic tracking sensor into the desired puncture site and ascertain puncture success. A tracked needle with a similar electromagnetic tracking sensor was subsequently navigated into the sensor in the catheter. Four punctures were performed by each of 2 surgeons in each pig, including 1 each in the kidney, middle ureter, and right and left sides. Outcome measurements were the number of attempts and the time needed to evaluate the virtual trajectory and perform percutaneous puncture.

RESULTS

A total of 24 punctures were easily performed without complication. Surgeons required more time to evaluate the trajectory during ureteral than kidney puncture (median 15 seconds, range 14 to 18 vs 13, range 11 to 16, p=0.1). Median renal and ureteral puncture time was 19 (range 14 to 45) and 51 seconds (range 45 to 67), respectively (p=0.003). Two attempts were needed to achieve a successful ureteral puncture. The technique requires the presence of a renal stone for testing.

CONCLUSIONS

The proposed electromagnetic tracking solution for renal collecting system puncture proved to be highly accurate, simple and quick. This method might represent a paradigm shift in percutaneous kidney access techniques.

Comparison of flexible and rigid cystoscopy-assisted ureteral catheter insertion before percutaneous nephrolithotomy: a prospective randomized trial

BACKGROUND AND PURPOSE

To compare the advantages of flexible and rigid cystoscopy-assisted ureteral catheter placement before prone percutaneous nephrolithotomy (PCNL).

PATIENTS AND METHODS

From March to September 2012, a total of 80 patients with kidney stones underwent PCNL by the same surgical team. The patients were randomly assigned into one of the groups according to the technique used for ureteral catheter insertion: Flexible cystoscopy (group 1, n=40) or rigid cystoscopy (group 2, n=40). Patient demographics and operation-related factors were compared. The preparation period included positioning, cystoscopy-assisted stent insertion, and patient repositioning for PCNL. In addition, discomfort scores of the operating room (OR) staff were measured.

RESULTS

The demographic values of the groups in terms of patient sex, age, body mass index, and stone size were comparable. While the mean preparation period was calculated as 9.9±2.3 minutes in the flexible cystoscopy group, it was significantly longer (19.7±2.9 minutes) in the rigid cystoscopy group (P<0.0001). In addition, the discomfort score of the OR staff was found to be significantly higher in the rigid cystoscopy group (1.1±0.9 vs 2.05±0.68, P<0.0001). The rest of the operative and postoperative parameters were similar.

CONCLUSIONS

The insertion of a ureteral catheter with a flexible cystoscope before prone PCNL shortens the preparation period and minimizes the discomfort of OR staff related to patient positioning and transfer.

Recent finding and new technologies in nephrolitiasis: a review of the recent literature

This review summarizes recent literature on advances regarding renal and ureteral calculi, with particular focus in areas of recent advances in the overall field of urolithiasis. Clinical management in everyday practice requires a complete understanding of the issues regarding metabolic evaluation and subgrouping of stone-forming patients, diagnostic procedures, effective treatment regime in acute stone colic, medical expulsive therapy, and active stone removal. In this review we focus on new perspectives in managing nephrolitihiasis and discuss recentadvances, including medical expulsive therapy, new technologies, and refinements of classical therapy such as shock wave lithotripsy, give a fundamental modification of nephrolithiasis management. Overall, this field appears to be the most promising, capable of new developments in ureterorenoscopy and percutaneous approaches. Further improvements are expected from robotic-assisted procedures, such as flexible robotics in ureterorenoscopy.

Percutaneous nephrostolithotomy: an assessment of costs for prone and Galdakao-modified supine Valdivia positioning

OBJECTIVE

To examine the relative costs of prone percutaneous nephrostolithotomy (PCNL) versus PCNL performed with the patient in the Galdakao-modified supine Valdivia (GMSV) position to determine whether a cost differential exists.

METHODS

We compared prone PCNL with PCNL using GMSV positioning. Cost data were obtained from the urology departmental and hospital billing offices at our institution and from the 2011 local Medicare reimbursement scales. The costs were divided into 5 major categories: surgeon fees, anesthesia fees, surgical supplies, hospital-related fees, and lost revenue.

RESULTS

The overall cost of prone PCNL ranged from $23 423 to $24 463, and the cost for PCNL performed with GMSV positioning ranged from $24 725 to $25 830. The difference between the 2 positions ranged from approximately $1302 for stones ≤ 2 cm to $1367 for stones >2 cm. The lost office revenue because of the requirement for a second surgeon was estimated at $1987.

CONCLUSION

Our assessment of the cost for prone versus GMSV PCNL technique found GMSV positioning to be more costly. The presence of 2 surgeons was the main driver of the cost differential, because it resulted in more equipment use, with greater instrument repair costs and higher surgeon fees. It also brings into consideration the opportunity cost of having a second surgeon in the operating room and not in the office.

A study on comparative outcomes of percutaneous nephrolithotomy in prone, supine, and flank positions

PURPOSE

To compare percutaneous nephrolithotomy (PCNL) safety and efficacy in prone, supine, and flank positions.

METHODS

A total number of 150 candidates for PCNL were randomly assigned into prone, supine, and flank groups. Patients in groups 1 and 2 underwent fluoroscopy-guided PCNL in prone and supine positions, respectively, while patients in group 3 underwent ultrasonography-guided PCNL in lateral position.

RESULTS

The success rates were 92, 86, and 88 % in prone, supine, and flank positions, respectively (P = 0.7). The mean access duration was 6.9 ± 4.2, 11.1 ± 5.8, and 10.8 ± 4.1 min (P = 0.08), and the mean operation time was 68.7 ± 37.4, 54.2 ± 25.1 and 74.4 ± 26.9 min (P = 0.04) in prone, supine, and flank groups, respectively. Pyelocaliceal perforation occurred in 2 (4 %), 2 (4 %), and 3 (6 %) patients in prone, supine, and flank positions, respectively (P = 1).

CONCLUSION

We believe that PCNL in both supine and flank positions are as safe and relatively effective as prone position in experienced hands. Preference of the surgeon and proper case selection for each procedure is very important and necessary.

Simultaneous antegrade/retrograde upper urinary tract access: Bart's modified lateral position for complex upper tract endourologic pathologic features

OBJECTIVE

To determine whether the Bart's modified lateral position is safe and effective for achieving simultaneous anterograde and retrograde access in complex upper urinary tract pathologic features.

METHODS

From November 2006 to September 2010, 45 procedures were performed, with the patients in the modified lateral position. The indication for these procedures was the presence of complex unilateral upper urinary tract pathologic features. The patients with muscular and/or skeletal abnormalities were excluded. All procedures were performed using simultaneous anterograde and retrograde access with the patient under general anesthesia.

RESULTS

The preoperative investigation protocol included assessment of the stone burden and location using enhanced abdominal computed tomography. The patients were routinely examined 6 weeks after the procedure with a combination of plain abdominal radiography and renal ultrasonography. For patients treated for conditions causing upper urinary tract obstruction (pelviureteral junction obstruction and/or ureteral strictures), a mercaptoacetyltriglycine renography was performed at 4, 12, and 24 months postoperatively. The mean patient age was 51.2 years (range 17-79). Stone clearance was achieved by a single combined procedure in 36 patients (80%). Successful recanalization was achieved in all patients with pelviureteral junction obstruction and ureteral strictures. In 4 patients (8.8%), persistent hematuria was noted, and 2 patients (4.4%) developed postoperative urinary sepsis and were treated conservatively.

CONCLUSION

Modification to the lateral position compares equally with contemporary percutaneous nephrolithotomy series. It provides wide exposure of the flank, allowing the choice of multiple access sites, enhanced control, and a wide angle for handling of the antegrade instruments. Two surgeons can work simultaneously, addressing complex endourologic pathologic features in high-risk patients.