Percutaneous Nephrolithotripsy With the Patient in a Modified Supine Position

Frequency and risk factors for antegrade ureteral stone migration after percutaneous nephrolithotomy

Introduction

Percutaneous nephrolithotomy (PCNL) is the minimally invasive procedure of choice for the treatment of large and/or complex nephrolithiasis. Migration of residual fragments (RFs) into the ureter after PCNL is presumed to be uncommon. However, should associated stone-related events (SREs) occur, ancillary procedures may be required. The objective of this study was to describe the frequency and to analyze predictors of antegrade migration of RFs after PCNL.

Material and methods

A case-control study of patients who underwent PCNL for nephrolithiasis and had a postoperative computed tomography available within 48 hours was performed. Descriptive statistics and logistic regression analysis were carried out.

Results

The final sample included 169 interventions. Mean age was 49 ±13 years, median maximum stone size was 26 (7 to 87) mm and mean stone density was 835 (70 to 2022) Hounsfield Units (HUs). 7.1% of the patients experienced migration of RFs into the ureter after PCNL, of whom 41.6% suffered SREs. Lithotripsy was performed using ultrasonic (67.5%), laser (23.7%), and pneumatic (14.8%) technologies. Univariate analysis found female gender (OR 4.1, p = 0.02) height ≥1.68 m (OR 5.52, p = 0.009), middle (OR 6.71, p = 0.01) and upper (OR 3.59, p = 0.04) caliceal location, staghorn calculi (OR 4.72, p = 0.02), stone area (OR 1.001, p = 0.03), lasertripsy (OR 3.61, p = 0.03) and operative time (OR 1.007, p = 0.02) statistically significant for migration of SFs into the ureter after PCNL. Of these, only height ≥1.68 m (OR 7.17, p = 0.01) and staghorn nephrolithiasis (OR 13.27, p = 0.02) remained independent predictors in the multivariate analysis with an area under the curve of 0.69.

Conclusions

71.% of patients undergoing PCNL had a SF migrating to the ureter. Of these 41% suffered a SRE that required ancilliary interventions. Staghorn nephrolithiasis and ≥1.68 mts of height were found to predict this event.

The role of ureteroscopy for treatment of staghorn calculi: A systematic review

Objective

To define the role of ureteroscopy for treatment of staghorn calculi.

Methods

A systematic review was conducted using the Scopus and Medline databases. Original articles and systematic reviews were selected according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Only studies relating to the role of ureteroscopy for treatment of staghorn calculi were included.

Results

In five studies on ureteroscopic monotherapy, stone-free rate (SFR) ranged from 33% to 93%, with a maximum four ureteroscopy sessions per patient and no major complications. Endoscopic combined intrarenal surgery (ECIRS) was compared with percutaneous nephrolithotomy (PNL) in two studies and reached significantly higher SFR (88%-91% vs. 59%-65%) and lower operative times (84-110 min vs. 105-129 min). The role of salvage ureteroscopy for residual stones after primary PNL has been highlighted by two studies with a final SFR of 83%-89%. One study reported on the feasibility of ureteroscopy for ureteral stones and same-session PNL for contralateral staghorn calculi, with a SFR of 92%.

Conclusion

Ureteroscopy plays a pivotal role in the setting of a combined approach to staghorn calculi. Ureteroscopy is also particularly suitable for clearance of residual stones. In specific cases, ureteroscopy may become the sole applicable therapeutic option to staghorn calculi. Technological advances and refinement of techniques suggest a major role of ureteroscopy for staghorn calculi treatment in close future.

Supine Percutaneous Nephrolithotripsy in Double-S Position

Background

At present, the percutaneous nephrolithotripsy (PCNL) is performed both in supine and in prone position. The aim of this paper is to describe an innovative position during PCNL.

Methods

We describe a supine position. The patient's legs are slightly abducted at the hips. The thorax is laterally tilted (inclination 30°–35°) and kept in the right position by one or two gel pads placed between the scapula and the vertebrae. External genitalia can be accessed at any time, so that it is always possible to use flexible instruments in the upper urinary tract. We used this position for a period of 12 months to treat with PCNL 45 patients with renal lithiasis.

Results

All the procedures were successfully completed without complications, using the position we are describing. The following are some of its benefits: an easier positioning of the patient; a better exposure of the flank for an easier access to the posterior renal calyces of the kidney; a lower risk of pressure injuries compared to positions foreseeing the use of knee crutches; the possibility of combined procedures (ECIRS) through the use of flexible instruments; and a good fluoroscopic visualization of the kidney not overlapped by the vertebrae.

Conclusions

This position is effective, safe, easy, and quick to prepare and allows for combined anterograde/retrograde operations.

Outcomes of more than 1 000 percutaneous nephrolithotomies and validation of Guy's stone score

OBJECTIVE

To present the experience with percutaneous nephrolithotomy (PCNL) at a high-volume Brazilian centre and to evaluate Guy's stone score (GSS) as a predictor of success and complications in PCNL.

PATIENTS AND METHODS

We prospectively evaluated patients who underwent PCNL between June 2011 and October 2016. Indications for PCNL included renal stones >2 cm in size and stones <2 cm in size in which first-line techniques had failed. All patients underwent a complete preoperative evaluation, including non-contrast-enhanced abdominal computed tomography (CT). Stone complexity was assessed using GSS. Success was defined as the absence of fragments >2 mm on CT on postoperative day 1. Complications were classified according to the Clavien grade.

RESULTS

A total of 1 066 PCNLs were performed on 891 patients. In all, 20.2% were classified as GSS1, 27.4% as GSS2, 35.0% as GSS3, and 17.4% as GSS4. The mean operating time was 108.44 min, and the mean fluoroscopy time was 13.57 min. The overall immediate success rate based on postoperative day 1 CT was 43.8%. Complications occurred in 14.9% of cases, and the mean length of hospital stay was 54.55 h. Stratifying patients according to GSS, success rate was inversely proportional to the calculus complexity: GSS1: 87.9%; GSS2: 62.1%; GSS3: 44.0%; and GSS4: 24.3% (P < 0.001). Higher GSS categories were significantly correlated with the number of puncture tracts (P < 0.001), operating time (P < 0.001), fluoroscopy time (P < 0.001), blood transfusion rate (P < 0.001), complications (P < 0.001) and length of stay (P < 0.001).

CONCLUSION

In a high-volume centre, PCNL was a reliable surgical technique, with low morbidity and short hospital stay. GSS was confirmed to be a very useful tool for predicting the outcomes of PCNL, and its use should be encouraged.

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.

Recent advancement or less invasive treatment of percutaneous nephrolithotomy

Since its initial introduction in 1976, percutaneous nephrolithotomy (PCNL) has been widely performed for the management of large renal stones and currently is recommended for staghorn calculi, kidney stones larger than 2 cm, and shock wave lithotripsy-resistant lower pole stones greater than 1 cm. However, except for open and laparoscopic surgery, PCNL is the most invasive of the minimally invasive stone surgery techniques. Over the years, technical and instrumental advances have been made in PCNL to reduce morbidity and improve effectiveness. A thorough review of the recent literature identified five major areas of progress for the advancement of PCNL: patient positioning, method of percutaneous access, development of lithotriptors, miniaturized access tracts, and postoperative nephrostomy tube management. This review provides an overview of recent advancements in PCNL and the outcomes of each area of progress and notes how much we achieve with less invasive PCNL. This information may allow us to consider the future role and future developments of PCNL.

Preoperative planning with noncontrast computed tomography in the prone and supine position for percutaneous nephrolithotomy: a practical overview

OBJECTIVE

To evaluate kidney/adjacent organs positional changes in patients undergoing percutaneous nephrolithotomy (PCNL) using noncontrast computed tomography (NCCT) in prone and supine positions.

METHODS

Patients scheduled PCNL were prospectively enrolled in the study and underwent NCCT in supine and in prone position (with boosters). Two imaginary lines for the posterior calyx of upper/mid/lower poles of both kidneys in prone and supine decubitus were considered and compared. Line I (LI): drawn horizontally in the coronal plane in contact with the posterior edge of the kidney. Line II (LII): drawn from the antero-lateral edge of the vertebra through the middle of the posterior calyx (ideal puncture line). Renal depth (d) was measured from LI to the anterior extremity of the vertebra. The maximum access angle (a) considered the window available in the axial plane to perform a secure approach to each calyx.

RESULTS

Thirty-seven patients were analyzed; 56.7% were female; mean BMI was 28.3±4.9 kg/m(2). For the right kidney, prone position was associated with more organs crossed by LI (54.1% vs 18.9%; p<0.01) and LII (56.8% vs 27%; p=0.03) in the upper calyx. For the left kidney, LII crossed more organs in prone in the upper calyx (54.1% vs 29.7%; p=0.03). Both kidneys showed a tendency to be deeper in the supine position, which provided a wider access angle.

CONCLUSIONS

Supine NCCT is not accurate to plan PCNL access in prone position. Prone decubitus is associated with more potential organ injuries in the upper pole. In supine, the kidney situates deeper in the abdomen but the access angle is wider than in prone.

Predicting calyceal access for percutaneous nephrolithotomy with computed tomography multiplanar reconstruction

OBJECTIVES

Objective parameters in computed tomography (CT) scans that could predict calyceal access during percutaneous nephrolithotomy have not been evaluated. These parameters could improve access planning for percutaneous nephrolithotomy. We aimed to determine which parameters extracted from a preoperative multiplanar reconstructed CT could predict renal calyceal access during a percutaneous nephrolithotomy.

METHODS

From January 2009 through April 2011, 230 patients underwent 284 percutaneous nephrolithotomies at our institution. Sixteen patients presented with complete staghorn calculi, and 11 patients (13 renal units) were analyzed. Five parameters were extracted from a preoperative reconstructed CT and compared with the surgical results of percutaneous nephrolithotomy.

RESULTS

Fifty-eight calyces were studied, with an average of 4.4 calyces per procedure. A rigid nephroscope was used to access a particular calyx, and a univariate analysis showed that the entrance calyx had a smaller length (2.7 vs. 3.98 cm, p=0.018). The particular calyx to be accessed should have a smaller length (2.22 vs. 3.19 cm, p=0.012), larger angles (117.6 vs. 67.96, p<0.001) and larger infundibula (0.86 vs. 0.61 cm, p=0.002). In the multivariate analysis, the only independent predictive factor for accessing a particular calyx was the angle between the entrance calyx and the calyx to be reached (OR 1.15, 95% confidence interval [CI], 1.053-1.256, p=0.002).

CONCLUSION

The angle between calyces obtained by multiplanar CT reconstruction is the only predictor of calyx access.

Free-flank modified supine vs. prone position in percutaneous nephrolithotomy: A prospective randomised trial

OBJECTIVE

To compare the technical aspects, operative time, safety and effectiveness of percutaneous nephrolithotomy (PCNL) in the free-flank modified supine position (FFMSP) vs. the standard prone position (SPP).

PATIENTS AND METHODS

Seventy-seven patients (47 men and 30 women) with renal stones were enrolled and systematically randomised into two groups, A (39 patients) treated using the FFMSP, and B (38 patients) in the SPP. The outcome was considered as a cure (successful procedure) if the patient became stone-free or had residual fragments of <4 mm in diameter. The operative time (from the induction of anaesthesia to the removal of the endotracheal tube) was measured and any operative complications or conflicts were recorded. The different variables were compared and analysed between the groups.

RESULTS

Patients in both groups had comparable preoperative clinical data and there were no significant differences in the preoperative clinical characteristics. The procedure was successful in 84.6% and 84% of group A and B, respectively. The operative time was significantly longer in group B (SPP) than A (FFMSP). There was no significant difference between the groups in fluoroscopy time and patients' outcome.

CONCLUSIONS

The FFMSP (with a cushion under the ipsilateral shoulder) has similar efficacy and safety as the SPP for PCNL and is associated with a significantly quicker operation.

Positions for percutaneous nephrolithotomy: Thirty-five years of evolution

Objectives

To present the chronological development of the different positions described for percutaneous nephrolithotomy (PCNL), in an attempt to identify the reasons for their development and to highlight their specific advantages and disadvantages.

Methods

Previous reports were identified by a non-systematic search of Medline and Scopus.

Results

The classic prone position for PCNL was first described in 1976. The technique was gradually standardised and PCNL with the patient prone became the generally accepted standard approach. In the next 35 years many other positions were described, with the patient placed prone, lateral or supine in various modifications. Modifications of the classic prone position in the early 1990s aimed to provide the option of a simultaneous retrograde approach during the procedure. As PCNL became more popular the lateral position was first described in 1994, to allow the application of PCNL to patients who were unable to tolerate being prone because of their body habitus. The supine position for percutaneous access was originally described even before 1990, but become more popular after 2007 when the Galdakao modification was reported. Several other modifications of the supine position have been described, with the latest being the flank-free modified supine position, which allows the best exposure of the flank among the supine positions. Each position has its specific advantages and disadvantages.

Conclusion

Urologists who perform PCNL should be familiar with the differences in the positions and be able to use the method appropriate to each case.

Flank free modified supine position: A new modification for supine percutaneous nephrolithotomy

OBJECTIVES

Percutaneous nephrolithotomy (PCNL) is the standard management for large and/or complex urolithiasis, but the standard patient position for PCNL is undecided. With the patient prone PCNL has several drawbacks, while when supine, as described previously, PCNL has mechanical limitations. We describe a modification that aims to overcome these limitations and provide easy access comparable to that in the prone position.

PATIENTS AND METHODS

This prospective study was carried out at the Urology Department, Zagazig University, Egypt, from October 2008 to March 2011, and included 78 patients (48 men and 30 women). First the patient was placed supine and then in the 'flank-free modified' supine position. The distance between the last rib and the iliac crest in the posterior axillary line was measured in both positions.

RESULTS

The mean age of the patients was 40.8 years, the mean (SD) stone diameter was 3.4 (0.7) cm, the number of right/left stones was 34/44, and mean body mass index was 28.8 kg/m(2). The mean (SD) increase in the distance between the last rib and the iliac crest in the posterior axillary line in the flank free modified supine position vs. the previous supine position was 12 (0.8) mm.

CONCLUSION

The flank-free modified supine position increases the distance between the last rib and the iliac crest, and, together with the absence of a cushion under the flank, provides ample space for puncture, dilatation, multiple tracts and manoeuvrability of the system with the nephroscope.

ECIRS (Endoscopic Combined Intrarenal Surgery) in the Galdakao-modified supine Valdivia position: a new life for percutaneous surgery?

BACKGROUND

Percutaneous nephrolithotomy (PNL) is still the gold-standard treatment for large and/or complex renal stones. Evolution in the endoscopic instrumentation and innovation in the surgical skills improved its success rate and reduced perioperative morbidity. ECIRS (Endoscopic Combined IntraRenal Surgery) is a new way of affording PNL in a modified supine position, approaching antero-retrogradely to the renal cavities, and exploiting the full array of endourologic equipment. ECIRS summarizes the main issues recently debated about PNL.

METHODS

The recent literature regarding supine PNL and ECIRS has been reviewed, namely about patient positioning, synergy between operators, procedures, instrumentation, accessories and diagnostic tools, step-by-step standardization along with versatility of the surgical sequence, minimization of radiation exposure, broadening to particular and/or complex patients, limitation of post-operative renal damage.

RESULTS

Supine PNL and ECIRS are not superior to prone PNL in terms of urological results, but guarantee undeniable anesthesiological and management advantages for both patient and operators. In particular, ECIRS requires from the surgeon a permanent mental attitude to synergy, standardized surgical steps, versatility and adherence to the ongoing clinical requirements. ECIRS can be performed also in particular cases, irrespective to age or body habitus. The use of flexible endoscopes during ECIRS contributes to minimizing radiation exposure, hemorrhagic risk and post-PNL renal damage.

CONCLUSIONS

ECIRS may be considered an evolution of the PNL procedure. Its proposal has the merit of having triggered the critical analysis of the various PNL steps and of patient positioning, and of having transformed the old static PNL into an updated approach.

La NLPC en décubitus dorsal modifié : notre expérience

RéSUMé: INTRODUCTION ET OBJECTIF :: La NLPC est conventionnellement réalisée en décubitus ventral. Cette position présente de nombreux inconvénients. Notre objectif était d'évaluer de façon prospective le caractère sûr et efficace de la NLPC en position de décubitus dorsal modifié (DDM). MATéRIEL ET MéTHODES :: Entre novembre 2004 et janvier 2010, 159 NLPC ont été réalisées en DDM. Le patient a été mis en décubitus dorsal avec un billot sous le flanc permettant une rotation de 45 degrés du côté opposé. Une position de lithotomie modifiée était associée si un double accès antérograde et rétrograde simultané était nécessaire. Après ponction rénale, la dilatation a été faite selon la technique « one shot » ou en utilisant les dilatateurs d'Alken. Les caractéristiques des patients et des calculs, la durée opératoire, le séjour hospitalier, les complications et le taux d'absence de calculs résiduels (« stone free ») ont été analysés. RéSULTATS :: L'âge moyen des patients était de 47 ± 13,1 ans (22-70). Vingt-et-un patients avaient des ATCD de chirurgie rénale du même côté. Vingt-six patients avaient un rein unique anatomique ou fonctionnel. Un patient avait un rein en fer à cheval et deux patients avaient une malrotation rénale. Le diamètre moyen des calculs était de 3,4 ± 1,9 cm (1,3-5,4) et 20 patients avaient des calculs coralliformes. Dix patients avaient des calculs urétéraux et ont eu une urétéroscopie simultanée. La durée moyenne de l'intervention était de 60 ± 29 min. Deux interventions ont été interrompues en raison d'un saignement important. Trois cas de fièvre postopératoire et 2 cas de fistule urinaire traités par sonde en double J ont été notés. Aucune plaie vasculaire ou viscérale n'a été rapportée ni de plaie pleuropulmonaire. Huit patients ont eu une seconde séance de NLPC durant la même hospitalisation. Après trois mois le taux d'absence de calculs résiduels était de 91,8 %.

CONCLUSION

La NLPC en DDM a permis de traiter de façon sûre et efficace les calculs rénaux. Elle a offert plusieurs avantages : facilité d'installation et non-nécessité de changer la position, pas de compression thoracique, moins de contraintes anesthésiques, réduction du risque de plaie colique et possibilité d'accès simultané antérograde et rétrograde.

The clinical research office of the endourological society percutaneous nephrolithotomy global study: staghorn versus nonstaghorn stones

PURPOSE

The study compared characteristics and outcomes in patients with staghorn or nonstaghorn stones who were treated with percutaneous nephrolithotomy (PCNL) within the Clinical Research Office of the Endourological Society (CROES) PCNL Global Study.

PATIENTS AND METHODS

Data over a 1-year period from consecutively treated patients from 96 centers worldwide were collated. The following variables in patients with staghorn or nonstaghorn stones were compared: National prevalence, patient characteristics, access method, puncture frequency and outcomes, including bleeding rates, operative time, and duration of hospital stay.

RESULTS

Data from 5335 eligible patients were collated; 1466 (27.5%) with staghorn and 3869 (72.5%) with nonstaghorn stones. Staghorn stone presentation varied between centers from 67% in Thailand to 13% in Argentina. The frequencies of previous procedures were similar between groups, but shockwave lithotripsy was less frequent in patients with staghorn stones compared with nonstaghorn (16.8% vs 22.6%) and positive preoperative urine cultures were more frequent in patients with staghorn than nonstaghorn stones (23.4% vs 13.1%). Patients with staghorn stones underwent multiple punctures more frequently than those with nonstaghorn stones (16.9% vs 5.0%). Postoperative fever, bleeding, and the need for blood transfusion were more frequent, the median operative time and duration of hospital stay were longer, while the proportion of patients remaining stone free was lower (56.9% vs 82.5%) in patients with staghorn than nonstaghorn stones.

CONCLUSIONS

The proportion of patients with staghorn stones varies widely between centers. Stone-free rates were lower, complications more frequent, and operative time and hospital stay were longer in patients with staghorn stones.

Percutaneous nephrolithotomy: Current concepts

Percutaneous nephrolithotomy (PNL) is the procedure of choice for large renal stones. Since its introduction in 1976, many aspects of the operative technique and the endoscopic equipments have had constant evolution, increasing the success rates of the procedure. We performed a literature search using Entrez Pubmed from January 2000 to July 2007 concerning PNL and many aspects related to all steps of the procedure.

We could verify that PNL in supine position has been proved as an acceptable option, but more worldwide experience is necessary. Urologists must be trained to gain their own renal tract access. Minipercutaneous PNL still needs equipments improvements for better results. Tubeless PNL is increasing in popularity and different tract sealants have been studied. Medical prevention is proved to be effective against stone recurrence and should be always used after PNL.

Although the evolution of the technique in the last 20 years, urologists must continue to improve their skills and develop new technologies to offer to the patients more and more a safe and effective option to treat large renal stones.

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

PURPOSE

To evaluate the efficacy and safety of percutaneous nephrolithotomy (PCNL) for patients in the supine position vs prone position.

MATERIALS AND METHODS

Eligible studies were identified from electronic databases (Cochrane CENTRAL, Medline and EMBASE). The database search, quality assessment, and data extraction were independently performed by two reviewers. Efficacy (stone-free rate, operative time) and safety (complication, such as fever and transfusion rate) were explored by using Review Manager 5.0. Sensitivity analysis was performed to explore the influence of low-quality studies.

RESULTS

Two randomized controlled trials and two case-control studies including 389 patients met the inclusion criteria. Meta-analysis of extractable data showed that PCNL in the supine position was associated with a significantly shorter operative time than PCNL in the prone position (mean difference: -24.84; 95% confidence interval [CI]: -34.45 to -15.23; P < 0.00001). There was no difference between the positions with regard to success rate (odds ratio [OR]: 1.16; 95% CI: 0.68-1.48; P = 0.59), complication (OR: 1.09; 95% CI: 0.67-1.80; P = 0.72), transfusion rate (OR: 2.19; 95% CI: 0.93-5.13; P = 0.07), and fever rate (OR: 0.39; 95% CI: 0.13-1.16; P = 0.09).

CONCLUSION

PCNL in the supine position took a shorter operative time than the prone position, but both positions appeared to be equivalent with regard to the stone-free rate and complication rate, transfusion rate, and fever rate. In brief, PCNL in the supine position is as effective and safe as PCNL in the prone position and was an alternate option for removal of renal calculi in PCNL.

Position: prone or supine is the issue of percutaneous nephrolithotomy

INTRODUCTION

The prone position has been considered the only position for percutaneous access to the kidney for the past 25 years, whereas the supine Valdivia position has recently started to gain acceptance, although it was originally described in the late 1980s. Even more recently, the Galdakao-modified supine Valdivia position was described. However, there is no consensus on which is the best position for percutaneous nephrolithotomy, and the choice is currently based on the surgeon's preference.

MATERIALS AND METHODS

The prone, supine, and modified supine positions are described, pointing out the advantages, disadvantages, and results of each technique.

RESULTS

A number of potential advantages have been described for the supine over the prone position: less cardiovascular change; no need for patient repositioning (with less associated risk of central and peripheral nervous system injury); less X-ray exposure to the surgeon; and less risk of colonic injury. The recently described Galdakao-modified supine Valdivia position allows for a simultaneous anterograde and retrograde approach to the renal cavities for the one-stage treatment of complex renal stones or concurrent renal and ureteral calculi. Moreover, the use of a flexible ureteroscope allows for Endovision puncture to achieve perfect access to the kidney.

CONCLUSIONS

The prone position still represents the standard for percutaneous access to the kidney, and other positions should be compared with this position. However, the supine and the modified supine positions have potentially important advantages for both patients and surgeons that need to be investigated in a large randomised trial to define their superiority over the traditional prone position.

Supine versus prone position in percutaneous nephrolithotomy for kidney calculi: a meta-analysis

BACKGROUND

Supine position and prone position were the choice for percutaneous nephrolithotomy (PCNL). However, there is still no consensus on the optimal position for PCNL.

METHODS

A systematic literature review was performed, searching Pubmed, Embase, CENTRAL and reference lists for relevant studies. Data from all selected articles were extracted independently by two reviewers and analyzed by RevMan 5 software.

RESULTS

Four comparative studies involving 389 cases and 27 case series studies including 1,469 renal units of supine position and 4,837 renal units of prone position were identified. With reference to comparative studies, the mean stone length and the proportions of staghorn and multiple stones were comparable between two positions. There was no significant difference in terms of stone-free rate (risk ratio = 1.00, 95% confidence interval: 0.92 to 1.09; 82.4 vs. 82.1%) and bleeding. The rate of colonic injury in supine PCNL was approximate 0.5% and incidence of pleural injury of 0% was noted for both positions. Pelvic perforation and failed access were comparable between supine and prone position. The operative times of supine position significantly decreased (65±15 vs. 90±15 min; mean difference = -24.76, 95% confidence interval: -39.36 to -10.15), but no significant difference was found in mean days hospital stay. Analysis based on the case series showed larger proportion of staghorn and multiple calculi in prone position (45.8 vs. 31.7%), the supine PCNL had slightly lower bleeding and similar stone-free rate compared with the prone position.

CONCLUSIONS

For general patients with kidney calculi, PCNL in supine position has similar stone-free rate compared with prone. Supine PCNL do not increase related complications. The operative times significantly decrease in supine position.

Percutaneous nephrolithotomy in the prone and prone-flexed positions: anatomic considerations

OBJECTIVES

Percutaneous nephrolithotomy is commonly performed in the prone position. Knowledge of renal anatomy and the relationship of adjacent organs is essential to minimize patient morbidity and iatrogenic organ injury. We present the anatomical basis for a prone-flexed modification to patient positioning and review the advantages and disadvantages of alternate positions.

METHODS

Triphasic computed tomography was conducted with the patient in supine, prone, and prone-flexed positions, and an anatomical survey was conducted. A 30 degrees angle was used to approximate the plane of nephrostomy access and the risk of organ injury.

RESULTS

For upper pole punctures, the liver and spleen were more medially situated, and thus more likely to be injured with supine positioning, compared with either prone or prone-flexed positioning (p < 0.001). In contrast, for lower pole punctures, the colon was more medially situated in the prone and prone-flexed positions compared to supine (p < 0.001). With prone-flexed positioning, the left kidney was displaced lower than the right in 92.3% of cases. The prone-flexed modification increased the distance from the posterior iliac crest to the 12th and 11th ribs by 2.9 and 3.0 cm, respectively (p < 0.001). If access was performed in the most superior calyx, this would have converted an upper pole access above the 11th rib to one above the 12th rib in 5 of 11 patients (45.5%).

CONCLUSIONS

Prone-flexed positioning is a simple modification that provides improved access to the upper pole and more mobility for lower pole percutaneous nephrolithotomy. This position is well tolerated and has several advantages over other patient positions, including the supine position.

X-ray-free percutaneous nephrolithotomy in supine position with ultrasound guidance

PURPOSE

Supine percutaneous nephrolithotomy (PCNL) has numerous benefits compared to the prone position, including lower anesthesia risk, shorter operating time, and better ergonomic position for the surgeon. It is also comparable to prone position regarding vascular and bowel injuries. This study was conducted to add some more benefits by omitting X-ray in PCNL in a supine position.

METHODS

Nineteen consecutive adult patients underwent ultrasound-guided PCNL in supine position. All patients were placed under ultrasound guidance in supine position. The tract was dilated over a guidewire in a single shot technique under ultrasound guidance from anterior abdominal wall. Once the procedure ended, residual stone was controlled using ultrasound with anterior abdominal wall window. Residual stones less than 5 mm were considered insignificant. No X-ray was used in any setting of the procedure.

RESULTS

The pelvicaliceal system could be successfully approached in all patients. The posterior calices were the most common sites of entry. Mean (range) of operation time was 111 (70-180) min. Mean + or - SD hemoglobin before PCNL was 14.0 + or - 2.2 mg/dl, and after the procedure it was 12.3 + or - 1.6 mg/dl. Only one patient required blood transfusion. Mean + or - SD creatinine before PCNL was 1.03 + or - 0.24 mg/dl, and after the procedure it was 1.11 + or - 0.22 mg/dl. None of the patients suffered visceral injury. The total stone-free rate was 84%.

CONCLUSIONS

Even in our first report with limited experience, it seems that the efficacy of PCNL with ultrasonography in supine position is comparable to PCNL in prone position with fluoroscopy with no more complications.

Complete supine percutaneous nephrolithotripsy comparison with the prone standard technique

PURPOSE

PCNL (percutaneous nephrolithotripsy) is usually performed in the prone position. The supine position has potential advantages comparing with the prone position. Our objective is comparison between the outcome of PCNL in the complete supine position and the standard prone position.

MATERIAL AND METHODS

A total of 80 patients who underwent PCNL from February 2008 to June 2008 evaluated in a prospective manner, were randomly divided into two groups: 40 patients underwent prone PCNL and 40 patients underwent complete supine PCNL. We performed complete supine PCNL with no rolled towel under the flank and no change in leg position. Results in both positions were compared regarding technical aspects, operative time, stone free rate, complications and hospital stay, and were analyzed using t-test and chi-square. We considered P < 0.05 as significant.

RESULTS

Regardless the position, the pelvicaliceal system could be successfully approached in all patients. Mean operative time in supine group was 74.7 +/- 25.1 min and less than prone group (106.87 +/- 17.5) with a significant statistical difference (P < 0.0001). Stone free rate was 80% and 77.5% in prone and supine position respectively. Mean hospital stay was similar in both groups. Bleeding requiring transfusion in two groups had not significant statistical difference. We had not colon injury.

CONCLUSION

PCNL in supine position is safe, effective and suitable for the patients. It offers the potential advantages of better urethral access, less patient handling, needing drape only once, ability to perform simultaneous PCNL and ureteroscopic procedures, better control of the airway during procedures, thus reducing over-all operative time compared to traditional prone position and performing PCNL while the surgeon is sitting. It may be considered for most patients requiring PCNL.

[PCNL: technical variations]

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

Endoscopic combined intrarenal surgery in Galdakao-modified supine Valdivia position: a new standard for percutaneous nephrolithotomy?

BACKGROUND

Percutaneous nephrolithotomy (PCNL), the gold standard for the management of large and/or complex urolithiasis, is conventionally performed with the patient in the prone position, which has several drawbacks. Of the various changes in patient positioning proposed over the years, the Galdakao-modified supine Valdivia (GMSV) position seems the most beneficial. It allows simultaneous performance of PCNL and retrograde ureteroscopy (ECIRS, Endoscopic Combined Intra-Renal Surgery) and has unquestionable anaesthesiological advantages.

OBJECTIVE

To prospectively analyse the safety and efficacy of endoscopic combined intrarenal surgery (ECIRS) in GMSV position for the treatment of large and/or complex urolithiasis.

DESIGN, SETTING, AND PARTICIPANTS

From April 2004 to December 2007, 127 consecutive patients who were followed in our department for large and/or complex urolithiasis were selected for surgery (American Society of Anesthesiologists [ASA] score 1-3, no active urinary tract infection [UTI], any body mass index [BMI]).

INTERVENTION

All the patients underwent ECIRS in GMSV position. Technical choices about percutaneous access, endoscopic instruments and accessories, and postoperative renal and ureteral drainage are detailed.

MEASUREMENTS

Patients' mean age plus or minus standard deviation (+/- SD) was 53.1 yr+/-14.2. Of the 127 patients, 5.5% had congenital renal abnormalities, 3.9% had solitary kidneys, and 60.6% were symptomatic for renal colics, haematuria, and recurrent UTI. Mean stone size+/-SD was 23.8mm+/-7.3 (range: 11-40); 33.8% of the calculi were calyceal, 33.1% were pelvic, 33.1% were multiple or staghorn, and 4.7% were also ureteral.

RESULTS AND LIMITATIONS

Mean operative time+/-SD was 70min+/-28, including patient positioning. Stone-free rate was 81.9% after the first treatment and was 87.4% after a second early treatment using the same percutaneous access during the same hospital stay (mean+/-SD: 5.1 d+/-2.9). We registered overall complications at 38.6% with no splanchnic injuries or deaths and no perioperative anaesthesiological problems.

CONCLUSIONS

ECIRS performed in GMSV position seems to be a safe, effective, and versatile procedure with a high one-step stone-free rate, unquestionable anaesthesiological advantages, and no additional procedure-related complications.