Risk of injury to adjacent organs with lower-pole fluoroscopically guided percutaneous nephrostomy: evaluation with prone, supine, and multiplanar reformatted CT

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.

Assessing the Variability of the Twelfth Rib as a Landmark for Percutaneous Nephrolithotomy Using Computed Tomography

BACKGROUND

The variability in length of the twelfth rib is mentioned in the literature but has never been formally studied. The highly variable rib length provides a challenge for urologists seeking a consistent landmark for Percutaneous Nephrolithotomy (PCNL). We set out to determine whether the twelfth rib is safe to use as a consistent landmark for surgery.

METHODS

Single centre, cross-sectional retrospective observational study and analysis of CT scans of 100 adults who had imaging between 23rd March and 12th April 2020. The distance from the mid-sagittal line to the twelfth rib tip in the axial plane was measured as was the distance from the twelfth rib tip to the kidney, spleen and liver.

RESULTS

Length from the mid-sagittal line to the right twelfth rib tip varied from 46 (percentile 95% CI 40 to 57) to 136mm (percentile 95% CI 133 to 138). On the left, the distances varied from 55 (percentile 95% CI 50 to 64) to 134mm (percentile 95% CI 131 to 135). Twenty-three percent of people had an organ lying between the tip of the twelfth rib and the kidney on the right and 11% on the left.

CONCLUSION

The twelfth rib is highly variable in length. Similar variability was recorded in the distance from the tip to intra-abdominal organs. Due to the frequency of organs lying between the tip of the rib and the kidney it should not be used as a landmark for accessing the kidney without prior knowledge of an individual patient's anatomy as seen on imaging.

Prevalence of the Retro-Renal Colon: A Systematic Review and Meta-Analysis with Implications for Percutaneous Nephrolithotomy

BACKGROUND

This systematic review and meta-analysis aims to determine the prevalence of the retrorenal colon (RRC) and its implications in percutaneous nephrolithotomy with the overall objective of promoting the prevention of associated iatrogenic complications.

METHODS

A systematic search of literature was conducted on the electronic databases PubMed, ScienceDirect, and Hinari to identify studies eligible for inclusion. Search results were screened by title and abstract, and those potentially relevant were evaluated by full text. Studies were deemed eligible for inclusion if they reported clear extractable data regarding the prevalence of the retro-renal colon. A meta-analysis was completed using MetaX1 to calculate the pooled prevalence of the retro-renal colon. Sub-group analysis was performed based on geographical regions from which the studies originated, imaging modality, and patient position.

RESULTS

174 records were screened and a total of 10 records included in the analysis with retrospective cohort studies being the most common study design. A male predominance was seen in most sample sizes that had reported data on gender demographics ranging from 41.5-62%. The most common imaging modality utilized was computerized tomography (CT) scan followed by ultrasound. The range of the unweighted prevalence of retro-renal colon across all studies that had absolute numbers reported was from 3.5-25%. One of the studies reported a colonic perforation rate of 0.3% in patients without CT images.

CONCLUSION

The retro-renal colon is a relatively common finding with observed preponderance to females and left lateralization. The presence of RRC increases the likelihood of colon perforations while gaining percutaneous access to the kidney. Pre-procedural imaging can help detect its presence and choose an appropriate route of entry. USG and CT have both been found useful as a modality to pick up RRC.

A new safe and ergonomic manipulation tool for the flank free supine position: 'U-Pad'

INTRODUCTION

One of the most important problems in the supine percutaneous approach to the kidney is the narrow surgical surface area (SSA) in the lumbar region. Herein, the spatial and angular geometric advantages of the U-shaped lumbar pad (U-Pad) used as a new positioning tool for safety and ergonomics in the supine percutaneous approach have been revealed.

MATERIALS AND METHODS

Data of patients who underwent endoscopic combined intrarenal surgery (ECIRS) using the U-Pad for kidney stones between March and September 2021 were prospectively collected. The demographic, preoperative, operative, and postoperative data of patients have been saved. The patients were positioned first with the standard gel pad (Group 1) and then with the U-Pad (Group 2). Both SSA (X and X+Y, cm2) and angular degree (α and β,0) calculations were compared. Fluoroscopy images with the same settings (97 kV/3.00 mA) were visually compared. In geometric data, trapezoidal area formula ((upper base+lower base) X height/2) and goniometer were used to compare with Paired t-test.

RESULTS

Endoscopic combined intrarenal surgery was performed on 17 patients, 13 men and, 4 women, with a median age of 39 (range 32-47). The median body mass index (BMI) was 26.2 (23.5-29.1). Stone localization and features were recorded. The median SSA was calculated as 35.7 cm2 in group 1 and 97.3 cm2 in group 2, and it was calculated that the total SSA increased to 272.5% with a median of 61.6 cm2 extra surgical area. Similarly, the downward manipulation angle was 320 (α0) in group 1, while it was 60.60 (β0) in group 2, and the median extra motion angle was calculated as 28.60 (89.3%).

CONCLUSION

The U-Pad is a safe and rapid tool in the supine percutaneous approach to the kidney, providing at least 2 times the extra SSA and manipulation angle.

Supine versus prone percutaneous nephrolithotomy for renal calculi: Our experience

Objectives:

To compare operative times, safety, and effectiveness of percutaneous nephrolithotomy in the supine versus the prone position.

Materials and methods:

An observational study of 100 patients was conducted in our institution for 2years from 2018 to 2020 divided into 2 groups: 50 patients underwent modified supine percutaneous nephrolithotomy (PCNL) and 50 patients underwent standard prone PCNL. The inclusion criteria included a renal calculus (calyx or pelvis) of any size for which PCNL was indicated and exclusion criteria were patients having contraindications for PCNL such as bleeding disorders, pregnancy, high risk, and co-morbid conditions. The measured data included operative time, number of punctures, stone-free rate, length of hospital stays, and rate of complications.

Results:

The 2 groups were comparable in mean age, male to female ratio, calculus size, number of punctures, residual calculi, and postoperative fever and pain. The mean difference of hemoglobin in the supine PCNL group was 0.37 g/dL whereas in the prone PCNL group it was 0.61 g/dL. The p value was significant at 0.043. The mean time to finish from initial postion was 72.24 minutes in supine PCNL and 88.12 minutes in prone PCNL. The p value was significant (p < 0.001). The mean time before puncture was 20.92 minutes in the supine position and 31.84 minutes in the prone position. The p value was significant (p < 0.001). The mean time from puncture to finish was 51.32 minutes in the supine position and 56.28 minutes in the prone position. The p value was significant (p < 0.001).

Conclusions:

As observed from this study, supine PCNL is associated with a significantly reduced operating time when compared to conventional prone position PCNL procedures. The postoperative complications such as pain and fever were not significantly different. Hence, the supine PCNL is an equally effective modality for treatment of a renal calculus with benefits of simultaneous retrograde access and less operative time compared to the prone PCNL.

A Percutaneous Nephrolithotripsy Performed in the Oblique Supine Lithotomy Position: A Better Choice

Objective. To investigate the efficacy and safety of the oblique supine lithotomy during percutaneous nephrolithotomy (PCNL) to treat upper urinary calculi. Methods. Clinical data were retrospectively analyzed for 371 patients with upper urinary calculi who underwent PCNL at The First Affiliated Hospital of Guangzhou University of Chinese Medicine from January 2017 to October 2020. Based on different positions, patients were divided into the observation group (oblique supine lithotomy position, 155 cases, Group 1) or control group (prone position, 216 cases, Group 2). Groups were compared for effectiveness, complications, bleeding, surgical time, clinical indicators, and hospitalization time. Results. There were no significant differences in the clinical baseline data between the two groups (p > .05). However, the stone-free rate for patients was significantly higher in the observation than in the control group (p < .05). Both operation time and hospital stay time were significantly lower in the observation versus the control groups (p < .05). No significant differences were observed for complications or amount of blood loss (p > .05). Conclusion. In patients with upper urinary calculi, percutaneous nephrolithotomy in the oblique supine lithotomy position has a higher stone-free rate than the prone position. This approach can shorten the operation and provide better comfort and quicker recovery to the patients. A further advantage is that there is no difference in safety and blood loss between the prone position and the oblique lithotomy position.

Incidence of posterolateral and retrorenal colon in supine and prone position in percutaneous nephrolithotomy

Colon injury is a distressing complication during percutaneous nephrolithotomy (PCNL). Posterolateral colon (PLC) and retrorenal colon (RRC) are known to be the risk factors of colonic injury during PCNL. We evaluated the incidence of PLC and RRC in both supine and prone position of patients who underwent PCNL in our institution, and determined the risk factors of PLC and RRC through a review of computed tomography (CT) scan. To define PLC and RRC, we divided kidney into anterior, anterolateral, posterolateral and retrorenal zone by drawing three parallel lines in the CT scan. Among a total of 102 patients, PLC and RRC were identified in 16 (15.7%) cases in supine, and 25 (24.5%) cases in the prone position. PLC and RRC were most frequently present in the upper and lower pole of the left kidney in prone position compared to supine (p value less than 0.001). Risk factors of PLC and RRC in the prone position were old age (over 68), lower body mass index (BMI), and thinner perirenal fat layer. Therefore, an initial percutaneous puncture in PCNL needs to be carefully accessed to those patients with such high risks of colon injury.

Diagnosis and management of small intestinal injury due to percutaneous renal access

PURPOSE

Define factors for proper diagnosis and treatment of small intestinal injury during procedures with percutaneous renal access, thus optimizing favorable outcomes and avoiding complications and death during conservative or surgical approaches.

MATERIALS AND METHODS

Bibliographic review of case reports available in the literature and presentation of data from an additional case have been carried out.

RESULTS

Percutaneous nephrolithotripsy was the procedure that most frequently caused injury of the small intestine. Time for diagnosis of the lesion took up to 5 days after the intraoperative phase. When occurring in the intraoperative phase, perforation was identified by direct endoscopic visualization; a catheter was then placed inside the intestinal lumen and a conservative approach to the derived fistula was adopted, which led to successful outcomes in all cases. Abdominal pain was the most common symptom in cases diagnosed during the postoperative phase (75%). In the presence of signs of peritonitis, surgical intervention was performed, with favorable evolution in all cases.

CONCLUSIONS

Conservative management of small intestine injuries is possible when there is no peritoneal contamination. Its success factors include intraoperative diagnosis and non-transfixing lesions, which is more common in duodenal involvement. Laparotomy to clean the cavity associated with a corrective approach (enterorrhaphy or enterectomy with primary anastomosis) was successfully indicated in cases of late diagnosis with signs of peritonitis, a situation that is most commonly found in transfixing lesions of ileum and jejunum.

New computed tomographic predictors of complicated perioperative course of 17.5F mini-percutaneous nephrolithotomy (mini-PNL)

PURPOSE

Radiological parameters predicting a postoperative stone-free status (SFS) or a complicated perioperative course of mini-PNL, are scarce. Our aim was to identify such factors for prone 17.5F mini-PNL.

METHODS

A monocentric cohort of 103 cases was retrospectively analysed for factors predicting SFS and relevant complications, i.e. Clavien-Dindo (CD) ≥ 2. Parameters measured on preoperative supine CT included maximal stone diameter, skin-to-stone distance (SSD), ideal tract length (ITL), access angle, minimal T12-Lower Kidney Pole distance (T12LP) and minimal Iliac Crest-Lower Kidney Pole distance (ICLP). Infundibulopelvic angle (IPA) was measured on intraoperative pyelography.

RESULTS

The median maximal stone diameter was lower in cases with postoperative SFS [16 mm (Min. 10; Max. 35) vs. 20 mm (Min. 6; Max. 85), p = 0.0052]. CD ≥ 2 was more frequent in cases with a bigger stone burden [19 mm (Min. 13; Max. 85) vs. 16 mm (Min. 6; Max. 49), p = 0.0056] and with the ribs in the access angle [7/23 (30.43%) vs. 8/76 (10.53%); p = 0.0454]. T12LP significantly differed in cases with and without CD ≥ 2 [80.48 mm (± 21.31) vs. 90.43 mm (± 19.42), p = 0.0397]; however, it had no influence on SFS (p > 0.05). SSD, ITL, IPA and ICLP were significant regarding neither SFS nor CD ≥ 2 prevalence (p > 0.05). Using multivariate logistic regression, T12LP was confirmed as an independent predictor on CD ≥ 2 prevalence.

CONCLUSIONS

Preoperative computed tomographic factors indicating elevated kidney position influence perioperative course of mini-PNL. T12LP and the presence of ribs in the access angle are, apart from stone diameter, the most useful indicators for cases at risk of CD ≥ 2.

A Different and Novel Alternative (ADANA) Renal Access Technique when CT or USG Guidance Is Inadequate in Case of Retro-Renal Colon

INTRODUCTION

Computed tomography (CT) or ultrasonography (USG)-guided renal access for percutaneous nephrolithotomy (PNL) is not suitable in all cases with retro-renal colon (RRC) due to anatomical and technical restrictions. We would like to describe our novel technique that permits standard subcostal renal access with a small incision for these patients.

METHODS

This method was performed on adult patients with severe RRC and complex renal stones who were not suitable for renal access with CT or USG guidance. Time from skin incision to puncture needle insertion, incision length, stone-free rate (SFR), and complications were evaluated.

SURGICAL TECHNIQUE

The appropriate renal calyx for renal access was identified with retrograde pyelography. The skin closest to the identified calyx was incised and retroperitoneum visualized. The RRC was swept laterally by blunt dissection to obtain a safe puncture line. The retractors were placed to keep the colon away from the incision. Then, the puncture needle was placed over Gerota's fascia. After this, the puncture needle was inserted into the targeted calyx under fluoroscopic guidance. The insertion of guidewire and the rest of the procedure such as dilatation and insertion of Amplatz sheath were performed under same maneuver.

RESULTS

A total of 1,348 patients were treated with PNL between January 2016 and November 2019. Our group consisted of 16 adult patients with a median age of 44.8 years (7 females and 9 males) who underwent PNL with our new access technique. SFR and clinically insignificant residual fragment (CIRF) rate were 72.5 and 14.2%, respectively. The median access time was 22.2 min (range: 15-30 min). The median skin incision length was 3.7 (range: 3.0-4.5) cm. The average skin incision length was 3.7 cm. The SFR and CIRF rate were 72.5 and 14.2%, respectively. We did not observe any complication related to our access technique.

CONCLUSION

Our novel access technique created a safe anatomical route for standard subcostal renal access with acceptable incision length and very low complication rate.

Ultrasonographic Detection of Retrorenal Colon in Prone Position: An Alternative to Computed Tomography

OBJECTIVE

To evaluate the correlation between ultrasonography (US) and computed tomography (CT) in prone position to detect retrorenal colon (RRC).

MATERIALS AND METHODS

In this prospective study, we included 310 patients who presented to our clinic between April 2017 and June 2019. All patients were evaluated for RRC with US and CT in prone position. Kappa compliance coefficient (κ) was used to express the compliance between CT and US outcomes.

RESULTS

This study included 119 (38%) female and 191 (62%) male patients with a mean age of 44.5 ± 16.1 years. With both CT and US, RRC was detected in a total of 42 (13.5%) patients. RRC was found in 9 patients (8%) on the right side, in 32 patients (18%) on the left side and in 1 patient on both sides with CT (P = .036). However, with US, it was detected in 10 patients (8%) on the right, in 31 patients on left side and in 1 patient on both sides (P = .083). The RRC detection compliance coefficients were excellent between US and CT (κ: 0.945).

CONCLUSION

US used in prone position is a suitable and practical imaging alternative to CT for detection of RRC.

Emergent Percutaneous Nephrostomy for Pyonephrosis: A Primer for the On-Call Interventional Radiologist

Pyonephrosis is gross accumulation of pus within an obstructed renal collecting system that, if left untreated, can lead to potentially fatal septic shock. Treatment requires urgent decompression coupled with systemic antibiotics. Percutaneous nephrostomy (PCN) placement, first described in 1976 for the treatment of pyonephrosis, is now widely utilized for emergent decompression in these patients. When performed by an experienced interventional radiologist, PCN is a safe procedure with technical success rates of over 96 to 99%. This article will address the clinical presentation of pyonephrosis, and will discuss the indications, technique, complications, and outcomes of emergent PCN placement. Additionally, the expanded indications for PCN placement in nonemergent scenarios will also be described.

Supine versus prone position for percutaneous nephrolithotripsy: A meta-analysis of randomized controlled trials

OBJECTIVE

To compare the safety and efficacy of percutaneous nephrolithotripsy (PCNL) in supine versus prone position for patients with renal or upper ureteral calculi.

METHODS

A systematic search of Pubmed, Embase and Cochrane Central Register of Controlled Trials was performed to identify all eligible studies. All included randomized controlled trials (RCTs) were evaluated based on the inclusion and exclusion criteria. After quality assessment and date extraction, a meta-analysis was performed using RevMan 5.3 software.

RESULTS

A total of 15 RCTs with 1474 patients were included in our meta-analysis. Pooled data showed that PCNL in supine position could significantly reduce the operative time [weighted mean difference (WMD) -12.02, 95% confidence interval (CI) -20.49 to -3.54, p = 0.005] and rate of fever [risk ratio (RR) 0.67, 95% CI 0.46 to 0.97, p = 0.03] compared to prone position. In addition, no significant differences could be found between groups in stone-free rate (p = 0.31), hospital stay (p = 0.59) and rate of overall complications (p = 0.11), mainly including urinary leakage (p = 0.83), pleural effusion (p = 0.74) and blood transfusion (p = 0.58).

CONCLUSIONS

The current study found comparable stone-free rate and significant lower rate of postoperative fever in supine PCNL compared with prone PCNL. PCNL in supine position could be a safe and efficient choice for patients with renal or upper ureteral calculi.

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.

Jejunal Injury as a Rare Complication of Percutaneous Nephrolithotomy: Case Report

Background: Colonic injury represents a rare complication of percutaneous nephrolithotomy (PCNL). Injury of the small bowel is very rare, with only anecdotal case reports in the literature. We report here a rare PCNL complication of jejunal perforation without concomitant colonic injury.

Case Presentation: A 45-year-old male underwent PCNL for multiple left kidney stones. At the beginning of the procedure, we faced difficulty in achieving access, but after that the procedure was straightforward and ended smoothly. However, from the third day, the postoperative course became stormy with progressive development of picture of acute peritonitis. Laparotomy was mandatory and jejunal perforation was found and repaired.

Conclusion: Although extremely rare, small bowel injury should be kept in mind during planning for percutaneous nephrolithotomy. Prompt diagnosis and active treatment should be undertaken without delay especially if picture of acute peritonitis is developed.

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.

[Renal artery embolization with exploratory laparotomy for management of massive colonic hemorrhage after renal biopsy: a case report]

We report a case of massive colonic hemorrhage after renal biopsy managed by renal artery embolization combined with exploratory laparotomy. Clinicians must be alert for such rare anatomical abnormalities as ectopic colon behind the kidney and the risk of colonic hemorrhage following renal biopsy. In this case, artery embolization combined with exploratory laparotomy successfully and quickly stopped the bleeding and avoided possible organ resection.

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.

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.

Supine pediatric percutaneous nephrolithotomy (PCNL)

INTRODUCTION/BACKGROUND

Many authors reported their experience with supine PCNL in adult population comparing the outcome with prone PCNL and they found that the stone free rate and the operative time were in favor of prone PCNL with a lower patient morbidity among patients with supine PCNL. This encouraged us to perform supine PCNL in pediatric population.

AN OBJECTIVE

In this study we evaluated the safety and efficacy of supine PCNL in pediatric population.

STUDY DESIGN (SUBJECTS/PATIENTS/MATERIALS/METHODS)

Between April 2011 and February 2014 a total of 27 children (6 girls and 21 boys) presented with renal calculi. The stones were single pelvic stone in 14 cases, pelvic stone with lower calyceal stones in 7 cases and pelvic stone with upper calyceal stones in 6 cases. The mean stone size was 32 mm (range 20-47 mm). All patients were managed with supine PCNL performed by a single surgeon. Marking the posterior axillary line in standing position before the operation is a mandatory initial step. The patients were placed in supine position with elevation of the ipsilateral shoulder and hip by means of two bags one underneath the shoulder and the other underneath the hip to widen the operative field. The technique was performed using a sheathless 19 fr. Richard wolf rigid nephroscope after acute tract dilation by amplatz dilators. Complications (intraoperative and postoperative) and stone free rate rates were reported.

RESULTS

A single lower calyceal access was used in all cases through which we could successfully remove even the upper calyceal stones. Kinking of the guide wire during tract dilatation were encountered in 4 cases and the guide wire was successfully exchanged using a small Teflon dilator in 2 cases while ultrasonographic guided lower calyceal repuncture was done in 2 cases. The average operative time (from the beginning of the puncture trial to nephrostomy tube insertion) was (41 ± 15) min. The operation was successfully completed as planned in all cases with two cases of intraoperative complications (one case of pelvicalyceal system perforation and another case of intraoperative bleeding and blood transfusion). The initial stone free rate was (92.5%). Postoperative complications was reported in the form of 2 cases of fever that respond to medical treatment for 72 h.

DISCUSSION

The main advantages of supine pediatric PCNL is that it is comfortable for the surgeon, the anesthetist and the child. The main disadvantages of supine pediatric PCNL is that it is not familiar for most urologists and small field of operation. The short outcome of our study is the small number of cases and the lack of comparative study with prone pediatric PCNL.

CONCLUSIONS

Pediatric supine PCNL is a safe and effective method for management of pediatric renal stones. It carries the advantages of easily upper calyx access through the lower calyceal tract, low incidence of fluid absorption or hypothermia and easy anesthesia monitoring. However a larger number of cases are needed to be evaluated.

An unusual presentation of colon perforation following percutaneous nephrolithotomy

Colon perforation is a rare but serious complication of percutaneous nephrolithotomy (PCNL), meriting particular attention to its signs and symptoms for prompt diagnosis and treatment. We report an unusual presentation of colon perforation following tubeless PCNL, characterized by sore throat, pneumomediastinum, and neck and shoulder crepitus. In addition to the details of this case, we review the current literature on bowel injury during PCNL and its management.

How well tolerated is supine percutaneous nephrolithotomy?

PURPOSE OF REVIEW

Supine percutaneous nephrolithotomy (PCNL) has been described in 1988 and several modifications followed since. Despite claimed benefits, supine PCNL is still neglected by the majority of urologists. Lack of experience and the fear of complications are possible explanations for the resistance to supine positioning. This review evaluates recent literature on the use of supine PCNL, focussing on benefits and safety.

RECENT FINDING

The Clinical Research Office of the Endourological Society Global Study and several (retrospective) reports comment on efficacy and safety of PCNL, differences in techniques, or identify conditions and patient factors for best practice. Anesthesiologic benefits (especially in the high risk, cardiopulmonary compromised, patient) and anatomical advantages are described in supine position theoretically favoring safety of supine PCNL. However, there are no prospective randomized studies conducted to support this assumption. Overall, benefits in efficacy or safety, of one position over the other, are not yet proven.

SUMMARY

Supine PCNL has advantages in selected patients. Ultimately, the decision on position should be made on patient's characteristics and surgeon's preference and experience.

Injury of the ileum during percutaneous nephrolithotomy in a pediatric patient

Ileum injury during percutaneous nephrolithotomy (PCNL) is an extremely rare complication. We describe the successful management of an inadvertently injured ileum during subcostal PCNL in a 12-year-old boy. Mechanism of injury, presentation and management will be discussed.

Investigation of the retrorenal colon frequency using computed tomography in patients with advanced scoliosis

PURPOSE

The aim of this study is to investigate the frequency of retrorenal colon in patients with advanced scoliosis.

MATERIALS AND METHODS

The existence of retrorenal colon was retrospectively investigated in 550 patients with vertebral scoliosis who had undergone abdominal CT scans at our institution between January 2008 and March 2012. The investigation was also carried out on a control group of 200 patients without scoliosis.

RESULTS

Among the 550 patients with scoliosis, 100 patients had advanced scoliosis necessitating treatment. Among these 100 patients with advanced scoliosis, retrorenal colon was detected in a total of 25 patients (25 %). The variation was observed on the right side in eight patients (two males, six females) (8 %), on the left side in 15 patients (five males, ten females) (15 %), and bilaterally in two patients (both females) (2 %). In the control group consisting of 200 individuals, retrorenal colon was detected in seven subjects (3.5 %), among which six were on the left and one was on the right. The difference between the incidence of retrorenal colon observed in the patients with advanced scoliosis and those without scoliosis was found to be statistically significant (p < 0.001).

CONCLUSION

Since the frequency of retrorenal colon in patients with advanced scoliosis is significantly higher than the control group without scoliosis, the risk of experiencing complications during renal interventions including renal biopsy is also higher. Therefore, these patients should undergo a detailed CT examination before these procedures, and renal interventions should be planned according to findings.

Prone versus modified supine position in percutaneous nephrolithotomy: a prospective randomized study

OBJECTIVE

To perform a prospective randomized trial comparing the efficacy and safety of percutaneous nephrolithotomy (PCNL) in the prone and modified supine positions.

METHODS

Between August 2010 and August 2011, 102 patients with renal calculi and 20 patients with ureteral calculi were randomized to undergo fluoroscopy and ultrasound-guided PCNL procedures in the prone or modified supine position. Baseline characteristics, puncture position, numbers of punctures, operation time, stone free rate, loss of blood, hospital stay and second phase PCNL were compared in the two groups.

RESULTS

There were no significant differences in gender, age, body mass index, stone location, stone size and the presence of hydronephrosis between the two groups. The rate of second PCNL was significantly higher and the stone clearance rate was significantly lower in the modified supine than in the prone position group. Mean operation time was significantly lower in the prone than in the modified supine position group (78 min vs 88 min, P<0.05). There were no significant differences in rates of rib and calyx puncture, numbers of punctures, mean blood loss, and mean hospital stay between the two groups.

CONCLUSIONS

Both the prone and modified supine positions are effective and safe for PCNL. Operation time was longer in the modified supine group, and patients undergoing PCNL in the modified supine position more frequently required a second operation due to a lower stone clearance rate.

Emergent percutaneous nephrostomy for the diagnosis and management of pyonephrosis

Emergent percutaneous nephrostomy is a potentially lifesaving procedure with a high technical success rate, minimal morbidity, and long safety record that is often used in the setting of an obstructed and infected renal collecting system (i.e., pyonephrosis). This article discusses all aspects of the emergent placement of nephrostomy catheters including indications, techniques, results, and complications. Differences between emergent and nonemergent placement of percutaneous nephrostomy catheters are also addressed.

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.

[Prone and supine position for percutaneous nephrolithotomy: is it necessary to change the operative technique?]

PURPOSE

To assess the safety and effectiveness of percutaneous nephrolithotomy performed in the supine position. To investigate whether the change in operative technique, between prone and supine position, is easy.

METHOD

Thirty patients who underwent percutaneous nephrolithotomy, by one surgeon in one hospital, were studied retrospectively. The eight first cases were performed in prone position, and the following 22 patients were operated in supine position according to Valdivia's operative technique. Data were analyzed with t-test. We considered P<0.05 as significant.

RESULTS

Surgical complication rate, transfusion rate and fever rate were the same for both groups. Success rate was 72% in supine position group and 63% in prone position group (P>0.05). These results were comparable with the data of the literature. Only operative time was shorter in supine position group with significant statistical difference (P=0.02).

CONCLUSION

In our experience, percutaneous nephrolithotomy in the supine position was safe and efficient, and outcomes were similar to that in the prone position. Learning curve was easy and fast.

Colon perforation during percutaneous renal surgery: a 10-year experience in a single endourology centre

The use of percutaneous renal surgery has been recently revolutionised with novel endourological instruments and techniques. However, the incidence, prevention and management of severe complications such as colon perforation still lack consensus. By presenting our 10-year experience, we would like to highlight the diagnosis and management of the rare complication of colon perforation.

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.

Computed tomography for percutaneous renal access

Abstract Successful percutaneous nephrolithotomy (PCNL) relies on appropriate preoperative planning and optimal percutaneous access. CT has now become the standard imaging tool for PCNL. For percutaneous renal access, CT may be used for planning access, guiding access, and in the follow-up after access. In this review, we discuss the role of each aspect for percutaneous access in PCNL. In particular, we describe the technique for gaining access using CT, a valuable method in the difficult collecting system.

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.

Lower-pole fluoroscopy-guided percutaneous renal access: which calix is posterior?

BACKGROUND AND PURPOSE

When obtaining fluoroscopy-guided lower-pole percutaneous renal access, knowledge of which calix is posterior is of paramount importance. Textbooks and peer-reviewed articles consistently refer to the most medial calix seen on fluoroscopy as posterior. We undertook this study to determine the orientation of the lower-pole calices to define the optimal site for lower-pole percutaneous renal access via a posterior calix.

PATIENTS AND METHODS

A retrospective review was performed of 101 renal units for patients who underwent routine contrast-enhanced abdomen/pelvic CT with delayed images for the workup of microscopic hematuria. Delayed images of the renal collecting system that were performed with patients in the supine position were analyzed for the study. Axial and coronal CT scans were evaluated by two observers, and the anatomic details of the lower pole were collected. Specifically, the number of minor calices in the lower pole (ie, two or three), the orientation of each minor calix (anterior facing, posterior facing), and the relative orientation of the minor calices (ie, which calix is most anterior, which calix is most posterior) were recorded. Exclusion criteria were: History of nephrolithiasis, history of renal surgery (open, laparoscopic, endoscopic, percutaneous), CT evidence of ipsilateral renal parenchymal or collecting system lesion.

RESULTS

CT scans were analyzed for 101 renal units (50 left, 51 right). For the lower pole, 42 (41.6%) renal units had two calices and 59 (58.4%) renal units had three calices. The most medial calix on coronal imaging was anterior facing in 95 (94.1%) kidneys, was the most anterior positioned calix in 84 (83.2%) kidneys, and was the most posterior positioned calix in 9 (8.9%) kidneys. Kidneys were then stratified by number of lower pole calices (two vs three). For the 42 renal units with two lower pole calices, the most medial calix on coronal imaging was anterior facing in 41 (95.2%) kidneys, was the most anterior positioned calix in 39 (92.9%) kidneys, and was the most posterior positioned calix in 2 (7.1%) kidneys. Of the 59 renal units with three lower-pole calices, the most medial calix on coronal imaging was anterior facing in 55 (93.2%) kidneys, was the most anterior positioned calix in 49 (84%) kidneys, and was the most posterior positioned calix in 4 (6.8%) kidneys.

CONCLUSIONS

For percutaneous lower-pole renal access, the most medial calix on coronal CT imaging and therefore retrograde opacification using fluoroscopy is almost always anterior facing and is the most anterior positioned in the majority of kidneys. Percutaneous lower-pole puncture should be directed at the more lateral calices because their posterior position and orientation provides optimal access to the collecting system for most cases. This anatomic understanding is critical for successful percutaneous nephrolithotomy.

Management of colon injury after percutaneous renal surgery

Percutaneous access to the kidney has gained widespread use during the last decades. Iatrogenic colon injury is an uncommon but serious complication. Diagnosis is sometimes delayed, and treatment strategies are still controversial, including conservative management, colostomy, or primary repair. The aim of this review is to identify optimal diagnostic and treatment options for such injuries.

[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.

Imaging modalities for urolithiasis: impact on management

PURPOSE OF REVIEW

Urolithiasis is a common urological problem, often requiring efficient workup, accurate diagnosis, and treatment. The purpose of this review is to summarize the imaging modalities employed for the diagnosis of calculi and the caveats of different clinical situations.

RECENT FINDINGS

Noncontrast computed tomography has become the most universally used imaging tool for diagnosing urolithiasis, although ultrasound and magnetic resonance imaging maintain specific roles. Noncontrast computed tomography may provide prognostic information regarding the success of specific management strategies for urolithiasis. Additionally, noncontrast computed tomography is being tested in lower-radiation dose protocols with promising results.

SUMMARY

Considering the well supported accuracy and relative ease of use of noncontrast computed tomography, it has become a logical choice for the urologist to use the technique as a diagnostic tool for stone disease. The future of imaging for intervention and surveillance of stone disease lies in the continued progress of noncontrast computed tomography in terms of patient safety. This will need to be done by developing low-dose radiation computed tomography that can replicate the efficacy of current noncontrast computed tomography.