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

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.

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.

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.

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.

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.

Effects of horizontal versus vertical bolster alignment on anatomical orientation of kidney as applied to prone percutaneous nephrolithotomy

PURPOSE

To evaluate the anatomical changes in kidney orientation in prone position with use of horizontal or vertical bolster alignment.

METHODS

Patients having renal stone(s) on ultrasonogram or X-ray underwent split bolus computed-tomo-urography (CTU) in prone position with horizontal and vertical bolster positions. CTUs were read by a single radiologist to quantify the cranio-caudal, antero-posterior, side to side and rotational movements of kidneys as relevant to prone percutaneous nephrolithotomy.

RESULTS

19 adult patients with 38 renal units and mean basal metabolic index of 25.6 kg/m² underwent CTU. Greater inferior displacement of both kidneys was seen with horizontal bolsters as compared to vertical bolsters. The right upper calyceal-diaphragm distance was 2.1 ± 1.5 cm and the lower calyceal-diaphragm distance was 2.0 ± 1.6 cm greater with the horizontal bolsters (p < 0.01). Similarly, the displacement on the left side was 1.5 ± 0.8 cm and 1.4 ± 0.8 cm, respectively (p < 0.01). Horizontal bolsters also result in significantly longer calyceal-skin distance at both poles of both kidneys [right upper: 0.4 ± 0.5 cm (p < 0.01), right lower: 0.8 ± 0.7 cm (p < 0.01), left upper: 0.4 ± 0.6 cm (p = 0.02), left lower: 0.8 ± 1.1 cm (p < 0.01)] and wider erector spinae-mid posterior calyceal-colon angle (124.8 v/s 110.0 on the right and 96.2 v/s 85.7 on the left) (p < 0.01).

CONCLUSION

Horizontal bolsters provide significantly more caudal displacement of the kidneys; the right kidney being displaced more as compared to the left. However, there is also an increase in the skin-calyceal distance with horizontal as compared to the vertical bolsters. These assessments may help the surgeons decide optimal bolster position individualized to the patient.

Celebrating 75 years

INTRODUCTION

Following the introduction of shock wave lithotripsy (SWL), ureteroscopy (URS), and percutaneous nephrolithotomy (PCNL), the subspecialty of endourology was born in the late 1970s. The purpose of this study was to report milestones in Canadian endourology, highlighting Canada's contributions to the field.

METHODS

A review of the literature was performed from the late 1970s to the present. The literature review included bibliographic and digital resources. Additionally, records and recollections by various individuals were used, including some who were directly involved.

RESULTS

Endourology was born in Canada when SWL, URS, and PCNL emerged as minimally invasive treatment options for stones in the early to mid-1980s. According to our research, the first PCNL was performed at the University of Toronto in 1981. Dr. Joachim Burhenne, a Harvard-trained radiologist from Germany, first used extracorporeal SWL in Canada at the University of British Columbia (UBC) for the treatment of biliary stones. Treatment for urinary tract stones followed at UBC and Dalhousie University. The first worldwide use of the holmium laser for lithotripsy of urinary tract calculi took place at the University of Western Ontario. Other endourology milestones in Canada include the formation of the Canadian Endourology Group and the emergence of the Endourological Society-accredited fellowship programs at the University of Toronto and Western University in the 1990s. Canada hosted the 21^st and 35^th World Congress of Endourology and Shock Wave Lithotripsy annual meeting in Montreal and Vancouver, respectively.

CONCLUSIONS

Canadian urologists have led many advances in SWL, URS, and PCNL over the past four decades and, for a relatively small community, have made significant contributions to the field. Through the training of the next generation of endourologists at Canadian institutions, the future of endourology in Canada is bright.

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.

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.

Exposure to Radioactive Emanations of Medical Personnel in Percutaneous Nephrolithotomy

The use of radioactive emanations has been of great importance for the performance of endourology procedures, such as percutaneous nephrolithotomy (NLP). The damage to health caused by radiation has been a sensitive issue. The objective of this work was to determine the dose received by the surgeon during NLP and the total dose generated by the fluoroscope. A cross-sectional study was conducted with data from a cohort study with a duration of 18 months that included 101 patients. Radiation was measured with dosimeter during the last 6 months. During the last 6 months of the study, 34 patients were submitted to surgery. The average age was 47 years. Average fluoroscopy time was 58.3 second (24-122 seconds) in both male and female groups, with 57.16 seconds and 58.95 seconds per case, respectively (P = .6). Radiation emitted during 6 months for the 34 patients was 330.5 mGy. The total radiation measured by the dosimeter was 1 mSv, which is equivalent to 0.3% of the total radiation applied during the procedures. Doses measured by the dosimeter on the surgeon were within the recommended annual doses although dose received by the hands exceeds the authorized limits (500 mSv/y).

Percutaneous nephrolithotomy: complications and how to deal with them

Percutaneous nephrolithotomy is a common surgical treatment for large and complex stones within the intrarenal collecting system. A wide variety of complications can result from this procedure, including bleeding, injury to surrounding structures, infection, positioning-related injuries, thromboembolic disease, and even death. Knowledge of the different types of complications can be useful in order to prevent, diagnose, and treat these problems if they occur. This review describes the diversity of complications with the goal of improving their avoidance and treatment.

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

INTRODUCTION

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

OBJECTIVE

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

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.

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.

Flank-free Modified Supine Percutaneous Nephrolithotomy in Pediatric Age Group

OBJECTIVE

To evaluate the safety and efficacy of pediatric percutaneous nephrolithotomy (PCNL) in the flank-free modified supine position (FFMSP). PCNL in the supine position is increasingly and successfully used in pediatric age group. Different modifications of supine positions have been described; however, the best supine position is not well established and remains a matter of debate.

PATIENTS AND METHODS

This prospective study included 22 children presenting with single renal pelvis stone (2-3 cm) in the period between May 2012 and April 2014. Diagnosis was set by plain x-ray and computed tomography in all patients. PCNL was performed with the patients placed in the FFMSP. The operative time and hospital stay were estimated. The outcome and any perioperative complications or conflicts were recorded.

RESULTS

The study included 22 children (15 boys and 7 girls) with a solitary renal pelvis stone. Mean ± standard deviation age of the patients was 9.5 ± 3.2 years (range, 3-15.5 years). Stone length, operative time, and hospital stay had mean ± standard deviation of 2.4 ± 0.23 cm, 65.1 ± 18.7 minutes, and 4.4 ± 0.9 days. Stone-free rate was 90.9% after 1 session of PCNL. One patient (4.5%) needed a second-look PCNL. Shock wave lithotripsy was performed for another patient. Postoperative fever occurred in 4 patients (18.2%). One patient received postoperative blood transfusion. Postoperative transient urinoma occurred in 2 patients (9.1%).

CONCLUSION

PCNL in pediatric age group via FFMSP was proved to be safe and effective in management of renal pelvis stones of size 2-3 cm. It provides stone clearance rate comparable with that reported of conventional PCNL in the prone position.

Fluoroscopy guided percutaneous renal access in prone position

Percutaneous nephrolithotomy is a very commonly done procedure for management of renal calculus disease. Establishing a good access is the first and probably the most crucial step of this procedure. A proper access is the gateway to success. However, this crucial step has the steepest learning curve for, in a fluoroscopy guided access, it involves visualizing a three dimensional anatomy on a two dimensional fluoroscopy screen. This review describes the anatomical basis of the renal access. It provides a literature review of all aspects of percutaneous renal access along with the advances that have taken place in this field over the years. The article describes a technique to determine the site of skin puncture, the angle and depth of puncture using a simple mathematical principle. It also reviews the common problems faced during the process of puncture and dilatation and describes the ways to overcome them. The aim of this article is to provide the reader a step by step guide for percutaneous renal access.

[Biopsies of the kidney, prostate and urinary bladder]

BACKGROUND

Biopsies of the kidney, prostate and urinary bladder are amongst the most frequent interventions in urology. A correct indication, preparation and performance are important to achieve good results and low complication rates.

OBJECTIVES

In this review complication management in biopsies of the kidney, prostate and urinary bladder are discussed.

MATERIALS AND METHODS

A selective search of the literature, with emphasis on systematic reviews and larger cohort studies was performed.

RESULTS

Complication rates are generally low. However, certain factors such as coagulation disorders, anatomical malformations, accompanying morbidities or antibiotic resistance may play a significant role and increase rates of complications. Especially complications such as hematuria and injury of contiguous organs are described in the literature.

DISCUSSION

Biopsies of the kidney, prostate and urinary bladder can be performed with low complication rates if general and specific factors in the planning of the intervention and prevention of complications are considered.

A randomized, double-blinded, placebo-controlled trial of intercostal nerve block after percutaneous nephrolithotomy

BACKGROUND AND PURPOSE

The optimal method of pain control after percutaneous nephrolithotomy (PCNL) remains controversial. We sought to determine whether intercostal nerve block with bupivicaine provided superior pain control, when compared with placebo, with a lower need for narcotics and improved health-related quality of life (HRQL) in the immediate postoperative period.

PATIENTS AND METHODS

Sixty-three patients were randomized to receive intercostal blockade with either 20 mL of 0.5% bupivacaine with epinephrine or 20 mL physiologic saline. All patients received intravenous narcotic patient-controlled analgesia (PCA) postoperatively. Data were collected on stone parameters, demographics, analgesic usage, length of stay, and HRQL as assessed by the Postoperative Recovery Scale.

RESULTS

The mean age was 47.7±1.2 years; mean body mass index was 28.0±5.0 kg/m(2); mean stone diameter was 29.2±15.8 mm. Within the first 3 to 6 hours after surgery, there was a significant reduction in narcotic use for the group receiving intercostal nerve blockade with bupivacaine compared with placebo. At 3 hours, narcotic use was 2.4±3.1 mg vs 4.3±3.8 mg morphine equivalents (P=0.034), and within 6 hours of surgery, narcotic use was 5.9±6.1 mg vs 8.8±7.4 mg (P=0.096). Durable improvement in HRQL was also observed in patients receiving intercostal nerve blockade with bupivacaine compared with placebo (P=0.034). No complications were attributable to the intercostal nerve blocks in either group.

CONCLUSIONS

Intercostal blockade with bupivacaine significantly improves both pain control and HRQL in the early postoperative period. The effectiveness of bupivacaine disappears within 6 hours of surgery, after which narcotic use becomes indistinguishable. Intercostal nerve blockade is an easy, safe, and inexpensive method that can be used to optimize pain control after PCNL.

Flank bulge following supracostal percutaneous nephrolithotomy: A report of 2 cases

Damage to intercostal nerves during surgical procedures has been associated with a postoperative flank bulge, due to denervation of the anterolateral abdominal wall musculature. This complication has not been reported following percutaneous nephrolithotomy (PCNL). We are aware of 3 cases, but have details on 2 cases of postoperative flank bulge following supracostal PCNL which are reported here. We also suggest how this complication could potentially be minimized.

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.

Diagnosis of femoral neck fracture associated with femoral shaft fracture: blinded comparison of computed tomography and plain radiography

OBJECTIVE

Femoral neck fractures that are associated with femoral shaft fractures have historically been associated with high rates of missed diagnosis. Despite the potentially serious consequences of a missed femoral neck fracture, little work has been conducted to rigorously evaluate the ability of commonly used imaging studies to detect such fractures. Our hypothesis was that axial-view computed tomography is superior to plain radiography at detecting femoral neck fractures.

DESIGN

Blinded assessment of a randomized image set that included axial-view computed tomographic scans of the pelvis, anteroposterior-view radiographs of the pelvis, and anteroposterior-view radiographs of the femur.

SETTING

Academic trauma center.

PATIENTS

Twenty-eight patients who had femoral shaft fractures with femoral neck fractures and 60 patients who had femoral shaft fractures without femoral neck fractures.

INTERVENTION

Images that were stripped of demographic data were independently viewed in random order on computer workstations by 5 trauma fellowship-trained orthopaedic surgeons who were blinded to treatment and diagnosis.

MAIN OUTCOME MEASUREMENTS

Sensitivity, specificity, positive post-test probability, and 1 minus negative post-test probability were calculated for diagnosing femoral neck fracture based on each image type.

RESULTS

Interobserver reliability showed "substantial agreement" (kappa > 0.65) for all imaging modalities, indicating that the surgeons had a high level of agreement. All 3 imaging sets had high specificity (>94%) and 1 minus negative post-test probability (>95%) but had poor sensitivity (<65%) and positive post-test probability (<58%). False positives and false negatives were equally likely for all imaging modalities (P > 0.2).

CONCLUSIONS

Plain radiography and computed tomography have rates of missed femoral neck fractures that are similar and substantial, with a sensitivity of only 56%-64%. Our data emphasize the importance of intraoperative and postoperative imaging in detecting nondisplaced femoral neck fractures in association with femoral shaft fractures.

Isolated upper pole access in percutaneous nephrolithotomy: a large-scale analysis from the CROES percutaneous nephrolithotomy global study

PURPOSE

We analyzed the indications for and outcomes of percutaneous nephrolithotomy using upper pole access.

MATERIALS AND METHODS

Between 2007 and 2009 prospective data were collected by the Clinical Research Office of the Endourological Society (CROES) from consecutive patients at 96 centers globally. Data on 4,494 patients were included in this analysis. Patients were divided into upper and lower pole access groups based on the location of percutaneous renal access. Preoperative characteristics and outcomes were compared between the 2 groups by univariate and multivariate tests.

RESULTS

The upper pole access group had more staghorn stones (21.7% vs 15.5%, p <0.001) and a greater stone burden (mean ± SD 476 ± 390.5 vs 442 ± 344.9 mm(2), p = 0.091). Mean operative time was 92.4 ± 46.1 and 75.1 ± 41.3 minutes in the upper and lower pole groups, respectively (p <0.001). The stone-free rate was lower in the upper pole access group (77.1% vs 81.6%, p = 0.030). The overall complication rate was higher in the upper pole group with a higher incidence of hydrothorax (5.8% vs 1.5%) but a lower incidence of pelvic perforation (1.8% vs 3.2%). Mean hospital stay was longer in the upper pole group (p = 0.048). Success and complication rates were similar in upper pole access subgroups, defined as definitive (staghorn and isolated upper calyceal stones) and elective (pelvic, middle calyceal and lower pole stones) indications.

CONCLUSIONS

Isolated upper pole access is indicated in a select group of patients with complex stones. Upper calyceal and staghorn stones are more commonly managed by upper pole access, which is associated with a higher complication rate and longer hospital stay as well as a lower stone-free rate due to procedure complexity.

Advances in percutaneous nephrolithotomy

Percutaneous nephrolithotomy (PCNL) is the most morbid of the minimally invasive surgeical procedures for stone removal. Over the last 2 decades, refinements in technique and new technology have improved the efficacy and the efficiency of the procedure. Although PCNL has long been the procedure of choice for large and complex stones, it is increasingly being used for moderate stone burdens because of its high stone-free rates and because of the limitations of shock wave lithotripsy and ureteroscopy. The article reviews advances in the technique and technology applied to percutaneous access, tract dilation, stone visualization, stone fragmentation, stone clearance, and postoperative management.

The Barts 'flank-free' modified supine position for percutaneous nephrolithotomy

BACKGROUND

The last decade has seen the emergence of a variety of supine positions for carrying out percutaneous nephrolithotomy (PCNL). These positions all differ with regard to ease of puncture under image guidance, operative field availability, ability to make and dilate multiple tracts and ease of combining retrograde intrarenal surgery (RIRS). As all of these positions have their limitations regarding the important parameters mentioned above, there is a need for a supine position which addresses some of the difficulties.

METHODS

We describe and illustrate our flank-free modified supine position, which we believe addresses a number of the issues.

RESULTS

Our position allows easy percutaneous access under fluoroscopy (torso only tilted to around 15°), space for placing (flank free of support) and dilating multiple tracts (kidney lies in a fairly neutral position and hence less mobile), a fairly horizontal tract allowing low intrarenal pressures and easy washout of fragments as well as allowing RIRS in a position of relative familiarity. The lesser torso rotation compared with the Valdivia, Galdakao modified and the Barts modified Valdivia positions also means it is more comfortable for patients.

CONCLUSIONS

Our results are encouraging and easily comparable with published series on prone position, Valdivia, complete supine and the Barts modified Valdivia positions. We would like to highlight the Barts 'flank-free' modified supine position as one of the standard positions for carrying out supine PCNL.

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.

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.

Comparison of supracostal versus infracostal percutaneous nephrolithotomy using the novel prone-flexed patient position

BACKGROUND AND PURPOSE

Percutaneous nephrolithotomy (PCNL) is considered standard therapy for large and complex renal calculi. The optimal patient position and puncture site for collecting system access remains controversial. This purpose of this retrospective review is to analyze our PCNL series with respect to puncture tracts, success, and complications using our novel prone-flexed position.

PATIENTS AND METHODS

Perioperative data were collected on consecutive PCNL cases for renal calculi performed in the prone-flexed position from 2004 to 2009. Patient demographic, stone, operative, postoperative, and follow-up data were collected. Successful treatment was defined as stone free or sandlike (≤1  mm) particles visible on CT scan at 3 months.

RESULTS

A total of 318 patients, with a mean age of 52.9 years and body mass index of 27.8  kg/m(2), underwent PCNL in the prone-flexed position (57.9% male). Sixteen tracts were above the 11th rib, 138 were above the 12th rib, and 164 were infracostal. Multiple tracts were used in 16 patients. There were no significant differences between patients undergoing supracostal vs infracostal puncture with respect to side, stone area, number of tracts, number of stones, or the presence of staghorn or struvite calculi. Success in the supracostal group (89.8%) was not statistically different from the infracostal group (94.1%), P>0.05. Overall complication rates across groups was low (11.6%), with a significant difference in complications between the supracostal and infracostal puncture groups across Clavien grades, P<0.01. No patients needed blood transfusions or angioembolization.

CONCLUSION

Regardless of supracostal or infracostal renal access, our novel prone-flexed position assists with percutaneous renal access and ease of nephrolithotomy, while maintaining excellent success rates and minimizing procedural morbidity.