Impact of percutaneous renal access technique on outcomes of percutaneous nephrolithotomy

Radiation exposure during different percutaneous renal puncture techniques: A YAU endourology & urolithiasis study

PURPOSE

Radiation exposure is affected by C-arm fluoroscopy device positioning during percutaneous renal puncture. Our aim was to compare the exposure of surgeon's lens, hand and chest with a fluoroscopy protocol replicated in different C-arm positions.

MATERIALS AND METHODS

A standardized fluoroscopy protocol was created using water-equivalent solid phantoms to replicate a surgeon and patient. 111 mGy radiation (360 s) was applied in standard fluoroscopy mode (91 kVp, 2.7 mA/mAs). Dosimeters were placed on lens, chest and hand of surgeon and patient phantom models. 7 different C-arm positions were created: 0°, mediolateral (ML) +90°, ML -90°, ML +30°, ML -15°, craniocaudal (CC) +30°, CC +15°. Measurements were evaluated separately for different positions.

RESULTS

The highest radiation exposure was measured on patient dosimeter (2.97 mSv). The highest exposure on surgeon was recorded on finger dosimeter in all C-arm positions; highest dose was recorded in ML +90° position (2.88 mSv). In finger dosimeters, lowest exposure was recorded in 0° position (0.51 mSv). The lowest exposure of all positions was measured in chest dosimeter in ML -90° position (0.24 mSv).

CONCLUSIONS

In positions where X-ray generator of the C-arm was facing towards the surgeon, radiation exposure measured in all dosimeters was higher compared to positions where the generator was facing away. The hand radiation exposure in all positions was higher than chest and lens. Special care must be taken to avoid facing the X-ray generator tube and hands should be as well-protected as chest and eyes with special protective gear.

Percutaneous nephrostomy for complex renal stones: Percutaneous renal access behind the stone versus renal calyx dilation

OBJECTIVE

To evaluate the technical success rate and complications associated with percutaneous nephrostomy (PCN) via percutaneous renal access behind the stone and renal calyx dilation in patients with complex renal stones.

MATERIALS AND METHODS

From January 2010 to February 2021, we identified 69 patients with 70 complex renal stones who underwent PCN. Complex renal stones were classified as simple (renal pelvis only) (27.1%, 19/70), borderline staghorn (8.6%, 6/70), partial staghorn (51.4%, 36/70), or complete staghorn (12.9%, 9/70). All PCNs were performed under ultrasound and fluoroscopic guidance using one of two renal-entry techniques: puncture behind the stone (56%, 39/70) or renal calyx dilation (44%, 31/70). Then, we retrospectively evaluated the technical success rates and complications associated with each renal entry access technique.

RESULTS

The overall technical success rate was 100%, and the complication rate was 20.0% (14/70). For those who underwent renal access behind the stone, the complication rate was 15.4% (6/39), and six patients (six PCNs) had transient gross hematuria. For those who underwent dilated renal calyx entry, the complication rate was 25.8% (8/31), and one patient had significant bleeding complications requiring transfusion. Furthermore, seven patients (seven PCNs) had transient gross hematuria. Overall, the complication rates did not differ between the technique groups (p = 0.279).

CONCLUSION

PCN for complex renal stones has a high technical success rate and an acceptable complication rate regardless of the specific technique. Renal entry behind the stone is as safe and feasible as approaching via a dilated renal calyx.

Access and Fluoroscopy Time Difference in Patients Undergoing Prone Percutaneous Nephrolithotomy (PCNL) With Ureteric Catheter Placement in Supine Versus Lithotomy Position

Objective: To compare the operative and fluoroscopy time in two different methods of ureteral stent insertion before prone percutaneous nephrolithotomy (PCNL).

Materials and method: Over 12 months, 124 patients with urolithiasis who went through prone PCNL were included in our study. All the patients had kidney stones and were divided into two groups based on the method of ureteral catheter insertion. This was done with the help of flexible or rigid cystoscopy in to group A and group B, respectively. Both groups had an equal number of patients, i.e., 62. The main outcome variables assessed were access time (from intubation to placement of access sheath) and fluoroscopy time during access.

Results: The categorical variables (age, gender, site of the stone) between the two groups were comparable. The access time in groups A and B were 48±4.30 and 77±10 minutes, respectively. The fluoroscopy times in groups A and B were 52±14.63 and 116±47.77 seconds, respectively. A statistically significant difference (p-value < 0.05) was observed for both the access and fluoroscopy time. None of the patients in either of the groups had a misplaced ureteral catheter requiring repositioning.

Conclusion: Flexible cystoscope-assisted insertion of ureteral catheter prior to PCNL significantly reduces operative time, fluoroscopy time, and consequently radiation exposure during PCNL.

Costovertebral angle as a novel tool for predicting the thoracic complication risk following percutaneous nephrolithotomy requiring supracostal access

INTRODUCTION

The objective of this study was to determine whether the costovertebral angle (CVA) and other factors can predict the risk of thoracic complications following percutaneous nephrolithotomy (PCNL).

METHODS

The data of patients who underwent prone PCNL with supracostal access at Suleyman Demirel University Hospital between January 2015 and December 2019 were retrospectively reviewed. Patients' demographics information (age, sex, body mass index [BMI], stone size, and stone location), operative data (supracostal access site, renal puncture site, and laterality), and postoperative thoracic complications (pleural injury) were evaluated. The CVA was measured on preoperative posteroanterior chest X-ray images. The mean CVA of patients with and without thoracic complications was evaluated.

RESULTS

A total of 89 patients (mean age 46.12±15.66 years; 59 men and 30 women) with supracostal access were included in the study. Thoracic complications occurred in 17 (19.1%) patients. Nine (52.9%) hemothorax cases, five (29.4%) pneumothorax cases, and three (17.7%) urinothorax cases were detected. There was a statistically significant difference in the complication rate compared to the percutaneous access site (10^th-11^th supracostal vs. 11^th-12^th supracostal, p=0.004). The mean CVA was significantly lower in patients with complications (45.47±3.59) than in those without complications (53.26±5.98) (p=0.000). No association was found (p>0.05) with age, sex, BMI, laterality, stone surface area, and access site among patients with and without thoracic complications.

CONCLUSIONS

Preoperative CVA can be an effective tool in predicting the risk of postoperative thoracic complications.

Trigonometric Concept of Fluoroscopy-Guided Percutaneous Renal Access

Percutaneous nephrolithotomy is the standard surgical management of large renal calculi. Percutaneous renal access using the triangulation method has been an enigma for the endourologist to master and teach. This surgical conundrum is due to the uncertainty in the angle and depth required to puncture the target calyx. We describe a novel trigonometric method of renal access where both the angle and the depth of puncture are easily determined before the puncture.

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.

Is emergency percutaneous antegrade drainage of the upper urinary tract useful for future percutaneous nephrolithotomy access?

Purpose

To compare percutaneous nephrolithotomy (PCNL) operations between patients with a preoperative nephrostomy tube and patients that the renal access was obtained at the time of the surgery.

Materials and Methods

We retrospectively evaluated PCNL cases. Patients were divided into two groups. Group 1 – a non-nephrostomy tube (percutaneous nephrostomy, PCN) group and Group 2 – patients with a PCN placed before the procedure. All preoperatively placed PCN's were performed in emergency situations by interventional radiologists (IR). Complications were classified according to the Clavien-Dindo classification. We compared stone characteristics, operation time, complications, efficacy and PCN usability at surgery.

Results

Five hundred twenty-seven patients who were submitted to PCNL for renal stones were included in the study. In 73 patients (13.9%) the PCNs were placed before the surgery. Patients and stone characteristics, mean operative time (p=0.830), complications (p=0.859) and stone-free rates (93.0%) were similar between the groups. There was a trend toward higher complication rates in Group 1, but the difference was not statistically significant. Only 21 (29.0%) of preoperatively placed PCNs were used during PCNL for establishing a tract. The reasons for not using PCN tract were: pelvic or infundibular insertion (30.0%) and suboptimal anatomic location (70.0%).

Conclusions

Preoperative emergency inserted PCNs by IR usage rates were low during PCNL. Its placement neither affects the incidence of complications nor affects the operation time and outcomes. As such, when emergency renal drainage is indicated, the need for a future definitive PCNL should not influence the decision about the modality of renal drainage.

Comparison of two different renal access techniques in one-stage percutaneous nephrolithotomy: triangulation versus eye of the needle

BACKGROUND

Two primary methods used to create appropriate percutaneous renal access under fluoroscopic guidance are the triangulation technique (TT) and the "eye of the needle" (EN) technique. To the best of our knowledge, no study has yet compared the EN versus TT renal access methods that precede one-stage dilatation during percutaneous nephrolithotomy (PCNL).

OBJECTIVES

Compare effects of renal access techniques on the stone-free rate of one-stage PCNL, and the influence on outcomes.

DESIGN

Retrospective cross-sectional study.

SETTINGS

Tepecik Training and Research Hospital, Turkey.

PATIENTS AND METHODS

The records of patients with renal stones larger than 2 cm in diameter who underwent PCNL in our hospital between January 2008 and September 2017 were retrieved. Patients who had undergone one-stage PCNL with the EN renal access technique (EN group) were compared with patients who had undergone one-stage PCNL with the TT renal access technique (TT group).

MAIN OUTCOME MEASURES

Operative time, stone size, access location, stone side, length of hospital stay, Hounsfield unit (HU), fluoroscopy time, change in hemoglobin level, complications (modified Clavien classification) and stone-free rate.

SAMPLE SIZE

195.

RESULTS

Of 272 records, 195 met inclusion criteria. The one-stage PCNL stone-free rate and other outcomes did not differ significantly between the EN (n=91, 46.7%) and TT groups (n=104, 53.3%).

CONCLUSION

According to our study, renal access for one-stage PCNL can be achieved using either the EN or TT technique. The renal access technique used does not independently affect the complication rate.

LIMITATIONS

Retrospective, small sample size, and no comparison of body mass index.

CONFLICT OF INTEREST

None.

Computer tomography urography assisted real-time ultrasound-guided percutaneous nephrolithotomy on renal calculus

This study aimed to assess the role of pre-designed route on computer tomography urography (CTU) in the ultrasound-guided percutaneous nephrolithotomy (PCNL) for renal calculus.From August 2013 to May 2016, a total of 100 patients diagnosed with complex renal calculus in our hospital were randomly divided into CTU group and control group (without CTU assistance). CTU was used to design a rational route for puncturing in CTU group. Ultrasound was used in both groups to establish a working trace in the operation areas. Patients' perioperative parameters and postoperative complications were recorded.All operations were successfully performed, without transferring to open surgery. Time of channel establishment in CTU group (6.5 ± 4.3 minutes) was shorter than the control group (10.0 ± 6.7 minutes) (P = .002). In addition, there was shorter operation time, lower rates of blood transfusion, secondary operation, and less establishing channels. The incidence of postoperative complications including residual stones, sepsis, severe hemorrhage, and perirenal hematoma was lower in CTU group than in control group.Pre-designing puncture route on CTU images would improve the puncturing accuracy, lessen establishing channels as well as improve the security in the ultrasound-guided PCNL for complex renal calculus, but at the cost of increased radiation exposure.

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.

Stone scattering during percutaneous nephrolithotomy: role of renal anatomical characteristics

The purpose of this study was to evaluate how the upper calyx-lower calyx infundibular (ULI) angle influences intrarenal stone migration during percutaneous nephrolithotomy (PCNL) in patients with a solitary renal pelvis stone and significant hydronephrosis. 50 adult patients with a solitary renal pelvis stone larger than 20 mm were considered for PCNL with a pneumatic lithotriptor for stone fragmentation. Inclusion criteria were moderate to severe hydronephrosis and upper calyx infundibular width >10 mm, and access point was the lower calyx in all cases. The ULI angle as well as stone fragment migration from the renal pelvis toward the upper calyx was noted during the operation. To determine the "critical" angle above which the probability of stone migration would be increased significantly, receiver operating characteristic curve was used. Mean stone size was 33.8 ± 13.2 mm. In 23 patients (46 %) the stone migrated toward the upper calyx during stone fragmentation. Mean ULI angle was significantly wider in patients whose stone migrated (120.2 ± 20.5 versus 102.2 ± 21.4, P = 0.004, 99 % CI = 6.04-29.9). A ULI angle of 117.5° was the critical angle, above which the rate of stone migration rose significantly (P < 0.008). One-session stone-free rate was significantly higher in patients without stone migration (P = 0.03). In patients with a solitary renal pelvis stone and significant hydronephrosis, a wider ULI angle was associated with a greater likelihood of stone scattering which could potentially affect the outcome of PCNL with pneumatic lithotriptor. A cut-off angle of 117.5° was the critical angle, above which access via a calyx other than the lower calyx (example: middle or upper calyx) seems advisable.

Endoscopic guided additional access for staghorn calculi

BACKGROUND AND PURPOSE

Flexible nephroscopy is an important technique in the management of staghorn renal calculi to reach peripheral calices. In this study, we present our experience with flexible nephroscopy and fluoroscopy-guided additional access creation for staghorn renal calculi.

PATIENTS AND METHODS

We conducted a retrospective analysis of patients with staghorn renal calculi who were treated with multiple percutaneous renal tracts created with the guidance of flexible nephroscopy and fluoroscopy. Additional tracts were performed with combined flexible nephroscopy and fluoroscopy guidance. Flexible nephroscopy was used to help target the calix and ensure the safety of access.

RESULTS

Additional percutaneous renal access was achieved using combined flexible nephroscopy and fluoroscopy guidance in 26 patients with complete staghorn (n=21) and partial staghorn (n=5) kidney stones. The cumulative stone size was 59.3 mm. The mean procedure times, fluoroscopy times, and hospitalization times were 91.5 minutes, 3.4 minutes, and 2.7 days, respectively. The postoperative hematocrit drop was 4.96±3.8. Upper and lower calices were the most common primary access tracts in 11 and 15 patients, respectively. Stone-free status was achieved in 22 (84.6%) patients with a mean 2.1±0.3 tract number. Postoperative complications were observed in six (23.1%) patients.

CONCLUSIONS

In the requirement of additional access for staghorn renal calculi, use of flexible nephroscopy with fluoroscopy increases the safety of the procedure by confirmation of precise renal access.

Body mass index predicts outcome of ureteroscopy-assisted retrograde nephrostomy for percutaneous nephrolithotomy

INTRODUCTION

Several clinical series of retrograde nephrostomy for percutaneous nephrolithotomy (PCNL) have been published over the past 30 years demonstrating good outcomes and safety. We previously reported our adaptation of the Lawson technique, wherein we deploy the puncture wire through a flexible ureteroscope. We herein aim to clarify the performance characteristics of this nephrostomy creation technique.

MATERIALS AND METHODS

Institutional Review Board approval and informed consent were obtained. A ureteroscopy-assisted retrograde nephrostomy (UARN) procedure was performed as described previously. Data were collected prospectively. Multiple patient and operative factors were evaluated for association with UARN success and nephrostomy creation time: body mass index (BMI), skin-to-stone distance, Guy's score, Clinical Research of the Endourological Society nephrolithometric score, hydronephrosis, stone burden, location of nephrostomy, exit from a stone-bearing calix, and use of holmium laser to access calix.

RESULTS

Nephrostomy was successful in 49/52 UARN procedures (94%). Only single access was placed: upper-18, mid-27, and lower-7. Median BMI was 29 kg/m(2) and median time for nephrostomy creation was 39 minutes. Fluoroscopy time for the entire PCNL including nephrostomy creation was 84 and 16 seconds for case numbers 1-25 and 26-52, respectively. By stepwise linear regression, variables correlating with nephrostomy creation time were BMI (r(2)=0.219), stone burden (r(2)=0.094), use of holmium laser to access calix (r(2)=0.104), and total r(2) linear=0.416.

CONCLUSIONS

UARN is an intuitive safe procedure that offers dramatic reductions in fluoroscopy times. UARN is best suited to cases requiring only one nephrostomy tract. Upper pole access is commonly performed with a subcostal technique to navigate the puncture wire below the ribs. Increasing BMI best predicts longer nephrostomy creation times; procedure failure was associated with BMI exceeding 40 kg/m(2). UARN is a robust technique for nephrostomy creation in appropriately selected patients.

Comparison of intrarenal pelvic pressure during micro-percutaneous nephrolithotomy and conventional percutaneous nephrolithotomy

The micro-percutaneous nephrolithotomy (microperc) is a recently introduced percutaneous nephrolithotomy (PNL) technique that is performed through a 4.8 Fr all-seeing needle. We aimed to measure the intrarenal pelvic pressure (IPP) during microperc and compare it with the levels of conventional PNL. A total of 20 patients with 1- to 3-cm renal calculi resistant to shock wave lithotripsy were treated either with microperc (Group-1, n: 10) or conventional PNL (Group-2, n: 10) by the same surgical team. The IPP was measured during different stages (entrance into the collecting system, stone fragmentation, and before termination) of the procedures by an urodynamic machine using the 6 Fr ureteral catheter. All the variables were statistically compared between the two groups. The demographic values of the patients were similar. The operation time and duration of hospitalization were significantly prolonged in conventional PNL group (p = 0.034, p = 0.01, respectively). The mean drop in hematocrit levels was significantly lower in microperc group (3.5 ± 1.5 vs. 1.8 ± 0.8; p = 0.004). The IPP was significantly higher in microperc group during all steps of the procedure. The highest level of the IPP was measured as 30.3 ± 3.9 and 20.1 ± 3.1 mmHg in Group 1 and Group 2, respectively (p < 0.0001). However, the complication and success rates were found comparable. In conclusion, we demonstrate that the level of IPP is significantly increased during microperc compared to conventional PNL. Microperc should be used cautiously in cases with impaired drainage of the collecting system.

Standardizing the reporting of percutaneous nephrolithotomy complications

Accurate reporting of complications is an essential component to critical appraisal and innovation in surgery and specifically with percutaneous nephrolithotomy (PCNL). We review the evolution of complication reporting for PCNL and suggest future directions for innovation. A selective review was carried out using Pubmed. Key search terms and their combinations included percutaneous, anatrophic, nephrolithotomy, PCNL, complications, Clavien, Martin score, bleeding, bowel injury, perforation, fever, sepsis. The references from relevant papers and reviews as well as AUA and EAU guidelines were also scanned for inclusion. PCNL has become the procedure of choice for large renal stones owing to decreased morbidity over alternative procedures. Both common and rare complications have been described in large case series, small randomized controlled trials, and case reports in an unstandardized form. Although these reports have provided an informative starting point, a standardized complication reporting methodology is necessary to enable appropriate comparisons between institutions, time periods, or innovations in technique. The Clavien-Dindo grading system has become widely accepted in urology and has facilitated the study of PCNL complications. Future research should focus on adaptions of this system to render it more comprehensive and applicable to PCNL.

The ideal puncture approach for PCNL: Fluoroscopy, ultrasound or endoscopy?

Percutaneous renal access is a common procedure in urologic practice. The main indications are drainage of an obstructed and hydronephrotic kidney and antegrade renal access prior to percutaneous renal surgeries such as percutaneous nephrolithotomy (PCNL) and percutaneous endopyelotomy (EP). The contraindications for this technique are patients with history of allergy to topical or local anesthesia and patients with coagulopathy. The creation of a percutaneous tract into the renal collecting system is one of the important steps for percutaneous renal access. This step usually requires imaging. The advantages and disadvantages of each modality of image guidance are controversial. We performed a structured review using the terms: Percutaneous nephrostomy, guidance, fluoroscopy, ultrasonography, computed tomography (CT) scan, and magnetic resonance imaging (MRI). The outcomes are discussed.

Endoscopic-guided versus fluoroscopic-guided renal access for percutaneous nephrolithotomy: a comparative analysis

OBJECTIVE

To evaluate the intraoperative outcomes of percutaneous renal access using fluoroscopic-guided access (FGA) vs endoscopic-guided access (EGA).

METHODS

A retrospective record review was conducted of patients undergoing percutaneous nephrolithotomy (PCNL), categorized by the method of achieving renal access. Patients were randomly assigned to 1 of 2 endourologists: 1 practicing EGA and the other practicing FGA. Patient demographics, baseline characteristics, and operative and postoperative outcomes were compared using univariate and multivariate analysis.

RESULTS

From August 2010 to January 2012, 159 patients underwent PCNL (40% EGA, 60% FGA). No significant difference was observed between groups in age (P = .06), American Society of Anesthesiologists Physical Status Classification (P = .7), number of stones (P = .058), cumulative stone diameter (P = .051), number of calyces involved (P = .82), and stone density (P = .49). Body mass index (BMI) was higher in patients undergoing EGA (P = .013). Patients undergoing EGA had shorter fluoroscopy time (3.2 vs 16.8 minutes, P <.001) and lower access number (1.03 vs 1.22 P = .002). Fluoroscopy time was longer for FGA than for EGA after adjusting for BMI, staghorn stones, and access number (P <.001). No significant difference was noted in change in hemoglobin, blood transfusion rate, operative time, or intraoperative complications between groups. Procedures were aborted due to bleeding more commonly in the FGA (8%) than in the EGA group (0%, P = .02) A secondary procedure for stone management was required in 2 (3.2%) of the EGA group compared with 12 (12.5%) of the FGA group.

CONCLUSION

EGA is safe and effective and leads to decreased fluoroscopy time, decreased need for multiple accesses, and decreased risk of early termination of the procedure or need for secondary procedures.

Monoplanar access technique for percutaneous nephrolithotomy

Percutaneous renal access is the most important step in percutaneous nephrolithotomy (PNL), and the adequacy of access directly affects the success and complication rates of this procedure. We use a monoplanar access technique that is different from biplanar method in that we utilize only fluoroscopic projections maintained on a vertical plane. The aim of this study is to evaluate the effects of this monoplanar access technique on operative outcomes. From October 2009 to December 2011, a total of 200 patients who had renal stones and underwent monoplanar PNL which done by the same surgical team were included in this study. Patient and procedure-related factors were recorded, as well as perioperation and postoperation variables such as operation time, puncture time, fluoroscopy screening time, complication rates, success rates, and duration of hospitalization. The average patient age at the time of procedure was 30.32 years. Mean operation and puncture time were 79.8 and 0.83 min, respectively. Stone-free rate was 80.5 % in postoperative day 1. After additional procedures such as shock wave lithotripsy (SWL), ureterorenoscopy and re-PNL final success rate was 98 % at third month including patients with clinically insignificant residual fragments. There were no severe complications except one patient in whom adjacent organ injury (colon) was observed. Monoplanar access is a safe and effective technique in PNL procedure. Furthermore less puncture time is an advantage of this technique.

The use of a biological model for comparing two techniques of fluoroscopy-guided percutaneous puncture: A randomised cross-over study

Objectives

To develop a new and inexpensive model for training in fluoroscopic puncture into the pelvicalyceal system, and to use this model to compare the learning curve of two fluoroscopic techniques, the ‘eye of the needle’ (EN) and triangulation techniques.

Materials and methods

For the trial we used a commercial plastic model (a shop-window mannequin) in which a bovine kidney, embedded in sponge with a spatial orientation similar to the human, was inserted into the model. The ureter of the animal kidney was connected to contrast fluid. Ten residents and interns were randomised into two groups; group A started the puncture using the EN technique, each member making five attempts, and then five attempts using the triangulation technique, and group B started with triangulation and then used the EN technique.

Results

There was no statistically significant difference between the techniques for the mean (SD) number of trials to make a correct puncture, at 2.68 (1.00) in the EN technique and 2.86 (1.05) in the triangulation technique, or for the duration of each trial, at 523 (189) s for the EN technique and 578 (175) s for the triangulation technique. The fluoroscopy time was less in the EN technique, at 113.9 (48.9) s than for the triangulation method, at 135.8 (42.4) (P < 0.005).

Conclusions

The model was easy to construct and feasible for training. Both techniques had a similar learning curve, with higher fluoroscopy exposure for the triangulation technique.

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

BACKGROUND AND PURPOSE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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