Ex vivo study of Ho:YAG and thulium fiber lasers for soft tissue surgery: which laser for which case?

The goal of this study was to assess the ablation, coagulation, and carbonization characteristics of the holmium:YAG (Ho:YAG) laser and thulium fiber lasers (TFL). The Ho:YAG laser (100 W av.power), the quasi-continuous (QCW) TFL (120 W av.power), and the SuperPulsed (SP) TFL (50 W av.power) were compared on a non-frozen porcine kidney. To control the cutting speed (2 or 5 mm/s), an XY translation stage was used. The Ho:YAG was tested using E = 1.5 J and Pav = 40 W or Pav = 70 W settings. The TFL was tested using E = 1.5 J and Pav = 30 W or Pav = 60 W settings. After ex vivo incision, histological analysis was performed in order to estimate thermal damage. At 40 W, the Ho:YAG displayed a shallower cutting at 2 and 5 mm/s (1.1 ± 0.2 mm and 0.5 ± 0.2 mm, respectively) with virtually zero coagulation. While at 70 W, the minimal coagulation depth measured 0.1 ± 0.1 mm. The incisions demonstrated zero carbonization. Both the QCW and SP TFL did show effective cutting at all speeds (2.1 ± 0.2 mm and 1.3 ± 0.2 mm, respectively, at 30 W) with prominent coagulation (0.6 ± 0.1 mm and 0.4 ± 0.1 mm, respectively, at 70 W) and carbonization. Our study introduced the TFL as a novel efficient alternative for soft tissue surgery to the Ho:YAG laser. The SP TFL offers a Ho:YAG-like incision, while QCW TFL allows for fast, deep, and precise cutting with increased carbonization.

Determining the Safety Threshold for the Passage of a Ureteral Access Sheath in Clinical Practice Using a Purpose-Built Force Sensor.

PURPOSE: Ureteral injury is a frequent complication of ureteral access sheath deployment. We sought to define the safe threshold of force for the passage of a ureteral access sheath using a novel ureteral access sheath force sensor. MATERIALS AND METHODS: Ureteral access sheath-force sensor measurements were recorded in 210 renal units. A 16Fr ureteral access sheath was deployed initially based on a prior porcine study. If 6 N was reached, the surgeon was advised to downsize the 16Fr ureteral access sheath. In each case, a post-ureteroscopic lesion scale was recorded. Regression models were used to estimate the impact of adjusted variables on post-ureteroscopic lesion scale grade, 16Fr ureteral access sheath deployment, and peak force. RESULTS: A 16Fr ureteral access sheath was deployed in 127 (61%) renal units with a mean peak force of 5.7 N. Two high-grade ureteral injuries occurred; in both cases >6 N of force was recorded. Post-ureteroscopic lesion scale grade correlated directly with peak insertion force (p <0.01). Bacteriuria within 60 days of the procedure (OR 2.009, p=0.034), combination of preoperative stent plus oral tamsulosin (OR 2.998, p=0.045), and prior ipsilateral stone surgery (OR 2.13, p=0.01) were independent predictors of successful 16Fr ureteral access sheath deployment. Among patients with neither prior ipsilateral stone surgery nor preoperative stent, preoperative tamsulosin facilitated passage of a 16Fr ureteral access sheath (OR 2.750, p=0.034). CONCLUSIONS: Ureteral access sheath associated ureteral injury can be averted by limiting the insertion force to ≤6 N. Prior stone surgery, preoperative indwelling ureteral stent plus oral tamsulosin, and recently treated bacteriuria favored passage of a 16Fr ureteral access sheath. In the naïve, unstented patient, preoperative tamsulosin favored deployment of a 16Fr ureteral access sheath.

Comparison of Conventional and Triple Bolus Computerized Tomographic Urography Protocols for Radiation Dose Reduction in Hematuria Evaluation: A Randomized Controlled Trial.

PURPOSE: Computerized tomographic urography is the diagnostic tool of choice for evaluating hematuria. In keeping with the ALARA (As Low As Reasonably Achievable) principle, we evaluated a triple bolus computerized tomography protocol designed to reduce radiation exposure. MATERIALS AND METHODS: Patients with macroscopic or microscopic hematuria were prospectively randomized to conventional computerized tomography (100) or triple bolus computerized tomography (100). The triple bolus computerized tomography protocol entails 2 scans: pre-contrast scan followed by 3 contrast injections at 40 seconds, 60 seconds and 20 minutes prior to the second scan to capture all 3 phases. The conventional computerized tomography protocol requires 4 scans: pre-contrast scan, and 3 post-contrast scans at the corticomedullary, nephrographic and excretory phases. Radiation exposure and the detection of urological pathology were recorded based on radiology reports. RESULTS: There were no differences in patient demographics or body mass index between the 2 groups. Triple bolus computerized tomography exposed patients to 33% less radiation (1,715 vs 1,145 mGy*cm for conventional vs triple bolus computerized tomography; p <0.001). For macroscopic hematuria, the pathology detection rates were 70% for triple bolus and 73% for conventional computerized tomography (p=0.72). For microscopic hematuria, the detection rates were 59% for triple bolus and 50% for conventional computerized tomography (p=0.68). In both groups, the rates of detection of urolithiasis, renal cysts, urological masses, bladder pathology and prostate pathology were no different between triple bolus and conventional computerized tomography. CONCLUSIONS: In both the settings of macroscopic and microscopic hematuria evaluation, triple bolus computerized tomography significantly reduces radiation exposure while providing equivalent detection of genitourinary pathology compared to conventional computerized tomography. The ability to detect upper tract filling defects was not specifically tested.

Characterization of intracalyceal pressure during ureteroscopy.

PURPOSE: To provide the first report of measuring intracalyceal pressures during ureteroscopy (URS). METHODS: A prospective single-center clinical study using a cardiac pressure guidewire to measure intracalyceal pressure during flexible URS was performed. Eight patients (45 calyces) undergoing URS for nephrolithiasis were included. A Verrata® pressure guide wire was passed through the working channel of a dual lumen flexible ureteroscope and into the calyces while irrigation was maintained at 150 mmHg. Pressure was measured in the renal pelvis, upper pole, interpolar, and lower pole calyces both with and without a ureteral access sheath (UAS). The pressure in each location with and without a UAS was compared. The correlation between calyceal pressure and infundibular dimensions (width, length) was determined. RESULTS: Intracalyceal pressure was significantly lower in each region when a UAS was used. Compared to patients with a 12/14Fr UAS, those with a 14/16Fr UAS had significantly lower pressure in the interpolar (25.3 ± 13.1 vs. 44.0 ± 27.5 mmHg, p = 0.03) and lower pole (16.2 ± 3.5 vs. 49.2 ± 40.3 mmHg, p = 0.004) calyces. Interpolar calyceal pressure in the presence of a UAS was significantly higher than the renal pelvis pressure (RPP) (30.8 ± 19.6 vs. 17.9 ± 11.0 mmHg, p = 0.004). CONCLUSIONS: During flexible URS, RPP strongly correlates with, but does not uniformly represent, the intracalyceal pressure. With a 14/16Fr UAS and an inflow pressure of 150 mmHg, RPP and intracalyceal pressure never exceed the threshold for renal backflow.

Office-Based Renal Tumor Biopsy: a Paradigm Change in the Management of a Small Renal Mass?

PURPOSE OF REVIEW: The goal of this paper is to evaluate the use of an office-based renal mass biopsy (RMB), whose feasibility could represent a paradigm shift in clinical practice. RECENT FINDINGS: Despite the earlier diagnosis of patients with renal masses, the lack of evidence showing a reduction in cancer-specific mortality warrants an examination in treatment practices. RMB is underutilized when compared to biopsy practice for all other neoplasms in every other solid organ (except testis), and the majority of RMB performed are outsourced to interventional radiologists. Performing an ultrasound-guided, office-based RMB is safe, reproducible, and has a meaningful impact on management decisions. The use of percutaneous RMB in clinical practice is growing, and the use of RMB has meaningful impact on management decisions for renal masses. Incorporating ultrasound-guided biopsy of a renal mass into clinical practice is feasible, and in contemporary practice, the urologist has the skill set to perform the procedure reliably, with low morbidity, and with minimal patient discomfort.

Monopolar enucleation versus transurethral resection of the prostate for small- and medium-sized (< 80 cc) benign prostate hyperplasia: a prospective analysis.

AIM: To assess efficacy and safety of monopolar enucleation of the prostate (MEP) and to compare it with the current treatment standard for medium-sized prostates, < 80 cc, transurethral resection of the prostate (TURP). METHODS: A prospective analysis patients undergoing a surgical procedure for their diagnosis of BPH (benign prostatic hyperplasia) (IPSS > 20, Qmax < 10; prostate volume < 80 cc) was performed. IPSS, Qmax were assessed preoperatively, at 6 and 12 months postoperatively. The complications were classified according to the modified Clavien-Dindo grading system. RESULTS: A total of 134 patients were included in the study: 70 underwent MEP and 64 - TURP for BPH (mean prostate volumes were comparable with p = 0.163). The mean surgery time was 44 min in the TURP group and 48.2 min in the MEP group, (p = 0.026). Catheterization time for MEP was 1.7 and 3.2 days for TURP (p < 0.001). Hospital stay for MEP was 3.2 days vs. 4.8 days for TURP (p < 0.001). Both techniques shown comparable efficiency in benign prostatic obstruction relief with IPSS drop in MEP from 23.1 to 5.9 and in TURP group from 22.8 to 7.3, whereas Qmax increased from 8.2 to 20.5 after MEP and from 8.3 and 19.9 after TURP. Urinary incontinence rate after catheter removal in TURP group was 9.0% and 7.8% in MEP group, at 1 year follow-up, it was 1.4% and 3.1% in MEP and TURP, respectively (p = 0.466). CONCLUSIONS: Our experience demonstrated that MEP is an effective and safe BPH treatment option combining the efficacy of endoscopic enucleation techniques and accessibility of conventional TURP.

Thulium-fiber laser for lithotripsy: first clinical experience in percutaneous nephrolithotomy.

PURPOSE: To evaluate the efficacy and safety of thulium-fiber laser (TFL) in laser lithotripsy during percutaneous nephrolithotomy (PCNL). METHODS: Patients with stones < 30 mm were prospectively recruited to undergo PCNL using TFL "FiberLase" (NTO IRE-Polus, Russia). Stone size, stone density, operative time, and "laser on" time (LOT) were recorded. Study included only cases managed with fragmentation. Stone-free rate and residual fragments were determined on postoperative computer tomography. Complications were classified using the Clavien-Dindo grade. Stone retropulsion and endoscopic visibility were assessed based on surgeons' feedback using a questionnaire. RESULTS: A total of 120 patients were included in the study with a mean age of 52 (± 1.8) years; of these 77 (56%) were males. Mean stone size was 12.5 (± 8.8) mm with a mean density of 1019 (± 375) HU. Mean operative time was 23.4 (± 17.9) min and mean LOT was 5.0 (± 5.7) min. Most used settings were of 0.8 J/25-30 W/31-38 Hz (fragmentation). The mean total energy for stone ablation was 3.6 (± 4.3) kJ. Overall stone-free rate was 85%. The overall complication rate was 17%. Surgeons reported stone retropulsion that interfered with surgery in 2 (1.7%) cases insignificant retropulsion was noted in 16 (10.8%) cases. Poor visualization was reported in three (2.5%) cases and minor difficulties with visibility in four (3.3%) cases. CONCLUSIONS: TFL is a safe and effective modality for lithotripsy during PCNL and results in minimal retropulsion.

A review of thulium-fiber laser in stone lithotripsy and soft tissue surgery.

PURPOSE OF REVIEW: To evaluate emerging evidence and practical applications of thulium-fiber laser (TFL) for genitourinary soft tissue disease and urinary stone disease treatment. RECENT FINDINGS: A systematic review was developed using the PubMed, ScienceDirect, Wiley, SpringerLink and Mary Ann Liebert Scopus databases between 2012 and 2020 years, using the PRISMA statement. We analyzed recent publications including in vitro and in humans outcomes of surgery using TFL. This new laser technology can be used in soft tissue diseases and stones present in the genitourinary system. Most of the comparisons are made with the Ho:YAG laser, using completely different settings. Nevertheless, TFL is safe, feasible and effective in the management of urologic diseases, showing superiority to Ho:YAG even in some studies. SUMMARY: The introduction of pulsed TFL technology has enabled the ablation of stones at rates comparable to or better than currently existing lasers in vitro, while also potentially reducing stone retropulsion. TFL is effective in treating genitourinary soft tissue diseases, including benign prostatic hyperplasia, and early data indicate that it may be effective in the treatment of urinary stone disease. More clinical studies are needed to better understand the indications for this novel technology and clarify its position in the urologic endoscopy armamentarium.

Applications of neural networks in urology: a systematic review.

PURPOSE OF REVIEW: Over the last decade, major advancements in artificial intelligence technology have emerged and revolutionized the extent to which physicians are able to personalize treatment modalities and care for their patients. Artificial intelligence technology aimed at mimicking/simulating human mental processes, such as deep learning artificial neural networks (ANNs), are composed of a collection of individual units known as 'artificial neurons'. These 'neurons', when arranged and interconnected in complex architectural layers, are capable of analyzing the most complex patterns. The aim of this systematic review is to give a comprehensive summary of the contemporary applications of deep learning ANNs in urological medicine. RECENT FINDINGS: Fifty-five articles were included in this systematic review and each article was assigned an 'intermediate' score based on its overall quality. Of these 55 articles, nine studies were prospective, but no nonrandomized control trials were identified. SUMMARY: In urological medicine, the application of novel artificial intelligence technologies, particularly ANNs, have been considered to be a promising step in improving physicians' diagnostic capabilities, especially with regards to predicting the aggressiveness and recurrence of various disorders. For benign urological disorders, for example, the use of highly predictive and reliable algorithms could be helpful for the improving diagnoses of male infertility, urinary tract infections, and pediatric malformations. In addition, articles with anecdotal experiences shed light on the potential of artificial intelligence-assisted surgeries, such as with the aid of virtual reality or augmented reality.

Comparison of silicone versus polyurethane ureteral stents: a prospective controlled study.

BACKGROUND: Approximately 80% of patients with indwelling ureteral stents experience stent related symptoms (SRS). We believe SRS can be reduced through altering the composition of ureteral stents to a less firm material. Therefore, we aim to compare modern silicone and polyurethane ureteral stents in terms of SRS intensity and safety. METHODS: From June 2018 to October 2018, patients from two distinct clinical centers were prospectively enrolled in the study and stratified (non-randomly) into either control group A, patients who received polyurethane stents (Rüsch, Teleflex), or experimental group B, patients who received silicone stents (Cook Medical). Each participant completed a survey 1 h after stent insertion, in the middle of the stent dwelling period, and before stent removal or ureteroscopy noting body pain and overactive bladder via the visual analog scale pain (VASP) and overactive bladder (OAB) awareness tool, respectively. Additionally, successfulness of stent placement, hematuria, number of unplanned visits, and stent encrustation rates were assessed within each group. RESULTS: A total of 50 patients participated in the study, control group A consisted of 20 patients and experimental group B consisted of 30 patients. Participants in group B, silicone ureteral stents, demonstrated significantly lower mean values of VASP 2 weeks prior to stent removal and promptly before stent removal (p = 0.023 and p = 0.014, respectively). No other comparisons between the two groups were statistically significant. CONCLUSIONS: Compared to polyurethane ureteral stents, silicone ureteral stents are associated with lower body pain intensity assessed by VASP 2 weeks before stent removal and at the time of stent removal. TRIAL REGISTRATION: Current Controlled Trials NCT04000178. Retrospectively registered on June 26, 2019.

Effect of positioning on ureteric stone retropulsion: 'gravity works'.

OBJECTIVE: To evaluate the potential impact of alterations in 'patient' position on laser-induced ureteric stone retropulsion in an in vitro model. MATERIALS AND METHODS: A ceramic (phantom) stone was placed in a water-filled clear polymer tube and subjected to continuous laser energy until the stone had retropulsed a distance of 10 cm. The trial was stopped after 60 s if the stone had not reached 10 cm. The time and total energy needed to cause 10 cm of retropulsion were recorded at incline angles of 0°, 10°, 20°, and 40°; 10 trials at each angle were completed. The study was then repeated with pure calcium phosphate brushite stones. RESULTS: Retropulsion decreased with increasing incline angle of the saline-filled clear polymer tube. At 0° of incline the phantom stone reached a distance of 10 cm after 7.4 s. At 10°, 20° and 40°, the phantom stone migrated a mean maximum distance of 3.1, 1.2 and 0.7 cm, respectively, and the trial was stopped after 60 s. For the calcium phosphate stone, at 0° and 10° of incline, the stone reached 10 cm after 6.9 and 42.8 s, respectively (P < 0.05). At 20° and 40°, the calcium phosphate stone moved a mean maximum distance of 2.4 and 1 cm, and the trial was stopped after 60 s. CONCLUSION: Alterations in the angle of inclination reduced stone retropulsion during ureteroscopic lithotripsy in an in vitro model to <1 cm. Increasing the incline angle of a patient may effectively preclude retropulsion when performing laser lithotripsy of ureteric stones.

Reducing kidney motion: optimizing anesthesia and combining respiratory support for retrograde intrarenal surgery: a pilot study.

BACKGROUND: One of the greatest challenges presented with RIRS is the potential for movement of the stone within the operative field associated with diaphragm and chest respiratory excursions due to mechanical ventilation. To overcome this challenge, we propose in this pilot study a new general anesthesia technique combining high frequency jet ventilation (HFJV) with small volume mechanical ventilation (SVMV). Data regarding safety, feasibility and surgeons' impression was assessed. METHODS: Patients undergoing RIRS for kidney stones from November 2017 to May 2018 were prospectively recruited to participate in the study. In each case after the beginning of general anesthesia (GA) with mechanical ventilation (MV) surgeons were asked to assess the mobility of the operative field and conditions for laser lithotripsy according to the developed questionnaire scale. The questionnaire consisted of 5 degrees of assessment of kidney mobility and each question was scored from 1 to 5, 1 being very mobile (extremely poor conditions for dusting) and 5 completely immobile (Ideal conditions for dusting). After the assessment GA was modified with combined respiratory support (CRS), reducing tidal volume and respiratory rate (small volume mechanical ventilation, SVMV) and applying in the same time transcatheter high frequency jet ventilation (HFJV) inside the closed circuit. After beginning of CRS, surgeons were once again asked to assess the mobility of the operative field and the conditions for laser lithotripsy. Main ventilation parameters were recorded and compared in both regimens. RESULTS: A total of 38 patients were included in the study. The mean age was 49 (range 45-53) with a mean stone size of 10 mm (range 10-14) and Hounsfield unit of 1060 (range 930-1190). All patients underwent successful RIRS and no intraoperative complications occurred throughout the duration of the study. A statistically significant difference between ventilation parameters prior to and after CRS institution was detected in all cases, however their clinical impact was negligible. Despite this, assessment via the questionnaire scale point values varied significantly before and after the application of CRS and were 2.3 (2.1; 2.6) and 3.8 (3.7; 4.0) respectively (p < 0.001). CONCLUSIONS: The novel combined respiratory approach consisting of HFJV and SVMV appears to provide better conditions for stone dusting through reduced respiratory kidney motion and is not associated with adverse health effects or complications. TRIAL REGISTRATION: NCT03999255 , date of registration: 25th June 2019 (retrospectively registered).

Medical impulsive therapy (MIT): the impact of 1 week of preoperative tamsulosin on deployment of 16-French ureteral access sheaths without preoperative ureteral stent placement.

INTRODUCTION AND OBJECTIVES: Medical expulsive therapy is based on pharmacologic ureteral relaxation. We hypothesized this concept may facilitate the deployment of the large 16 French (F) ureteral access sheath (UAS) when patients are intentionally pre-treated with oral tamsulosin, i.e., medical impulsive therapy. METHODS: We retrospectively analyzed our experience with UAS deployment during endoscopic-guided percutaneous nephrolithotomy in prone position in patients pre-treated for 1 week with oral tamsulosin with a contemporary untreated cohort. Between January 2015 and September 2016, seventy-seven patients without a pre-existing ureteral stent met inclusion criteria. Demographic data, tamsulosin usage, UAS size, deployment failure, ureteral injuries, stone-free rates, and complications were recorded. Univariate and multivariate analysis was conducted to assess the impact of tamsulosin on deployment of the 16F UAS. RESULTS: There was no statistical difference between the tamsulosin (n = 40) group and non-tamsulosin (n = 37) group in regard to demographic data. The tamsulosin group had a significantly higher percentage of 16F UAS deployment, 87 vs. 43% (p < 0.001), and no significant difference in ureteral injuries (p = 0.228). Univariate and multivariate analysis revealed that tamsulosin significantly increased the odds ratio (9.3 and 19.4, respectively) for successful passage of a 16F UAS. Despite a larger stone volume, there was no significant difference in computed tomography scan complete stone-free rates (29 vs. 42%; p = 0.277) at median post-operative time of only 3 days. CONCLUSIONS: In this retrospective study, 1 week of preoperative tamsulosin was associated with an increase in the deployment of a 16F UAS in patients without preoperative ureteral stent placement.

Percutaneous renal biopsy: approach, diagnostic accuracy and risks.

PURPOSE OF REVIEW: This article provides a review of recent advances and issues regarding the controversial topic of renal mass biopsy (RMB). The purpose of this review is to provide an update on the current status of renal biopsy based on recently published literature. Here, we particularly focus on articles that have been published within the last 12 months. RECENT FINDINGS: The main topics covered in this review are the approach, diagnostic accuracy and risks related to RMB. SUMMARY: Current literature suggests that improvements in both technique and technological advancements of RMB have led to greater diagnostic accuracy and low risks to the patient. Newer technologies are leading toward innovative and harmless ways to diagnose kidney cancer, including liquid and image-based biopsy. However, it appears that the question of whether or not to instate renal biopsy as standard clinical practice has remained a highly debated controversy.

Renal mass biopsy: an oncological conundrum.

PURPOSE OF REVIEW: We evaluate the reasons that the majority of urologists infrequently biopsy a T1a small renal mass (SRM). RECENT FINDINGS: The majority of urologists report that a renal mass biopsy will not change their management in patients with a SRM given concerns of safety and efficacy of the biopsy. However, when comparing the safety and efficacy of SRM biopsy with neoplasms in all other major organ systems (all of which require biopsy prior to treatment), renal mass biopsy results are favorable. In addition to being safe and effective, renal mass biopsy should be more cost-effective for the healthcare system. Finally, in properly selected patients, renal mass biopsy can be performed in the urologist's office, thereby further decreasing cost. SUMMARY: Renal mass biopsy is an essential clinical tool that needs to be incorporated into the decision-making process among patients with a T1a SRM. A biopsy-driven, tissue-specific diagnosis of SRMes should become the standard of care in urology to bring us to parity with standard practice to management of lesions identified in every other organ system.

Impact of endoscopic enucleation of the prostate with thulium fiber laser on the erectile function.

BACKGROUND: The impact of number of endoscopic enucleation of the prostate techniques (holmium laser enucleation - HoLEP for example) on erectile function have already been investigated. However, the thulium-fiber laser, in this setting remains unstudied. In this study, we compared sexual function outcomes in patients with benign prostatic hyperplasia (BPH) treated with transurethral resection of the prostate (TURP) or thulium-fiber laser enucleation (ThuFLEP). METHODS: We performed a retrospective analysis of patients who underwent transurethral resection and endoscopic enucleation of the prostate for BPH; inclusion criteria was the presence of infravesical obstruction (IPSS > 20, Qmax < 10 mL/s). Erectile function (EF) was assessed using the International Index of Erectile Function (IIEF-5) both prior to endoscopic examination, and six months after. RESULTS: A total of 469 patients with BPH were included in the study; of these, 211 underwent to ThuFLEP, and 258 TURP. Preoperative IIEF-5 in TURP and ThuFLEP groups were 11.7 (±4.5) and 11.1 (±5.0), respectively (p = 0.17). At six month the IIEF-5 score was unchanged (p = 0.26 and p = 0.08) and comparable in both groups (p = 0.49). However, mean IIEF-5 score shown significant increase of 0.72 in ThuFLEP group, comparing to decrease of 0.24 in TURP patients (p < 0.001). CONCLUSIONS: Both TURP and ThuFLEP are effective modalities in the management of infravesical obstruction due to BPH. At six months follow-up after surgery, both techniques lead to comparable IIEF-5 score. However, our results demonstrated that the ThuFLEP is more likely to preserve the erectile function leading to increase of IIEF-5 at six months in contrast to TURP which lead to slight drop in IIEF-5 score.

Precise Characterization and 3-Dimensional Reconstruction of the Autonomic Nerve Distribution of the Human Ureter.

PURPOSE: We sought to characterize and 3-dimensionally reconstruct the distribution of the autonomic innervation of the human ureter. MATERIALS AND METHODS: Three male and 3 female pairs of ureters were evaluated at 2 mm serial transverse sections along the entire length of the ureter. The location of nerve tissue was immunohistochemically identified using the neuronal marker, S100 protein. ImageJ software was used to calculate nerve count and density in the adventitia and smooth muscle. Blender® graphics software was used to create a 3-dimensional reconstruction of autonomic nerve distribution. RESULTS: Within the adventitia nerve density was highest in the mid and distal ureter (females 2.87 and 2.71 nerves per mm2, and males 1.68 and 1.69 nerves per mm2) relative to the proximal ureter (females and males 1.94 and 1.22 nerves per mm2, respectively, p >0.0005). Females had significantly higher nerve density throughout the adventitia, especially in the distal ureter (2.87 vs 1.68 nerves per mm2, p <0.0005). In smooth muscle the nerve density progressively increased from the proximal to the distal ureter (p >0.0005). Smooth muscle nerve density was similar in the 2 genders (p = 0.928). However, in females nerve density was significantly higher in the first 2 cm of the distal ureter relative to the second 2 cm (3.6 vs 1.5 nerves per mm2, p <0.001) but not in males (3.0 vs 2.1 nerves per mm2, p = 0.126). CONCLUSIONS: Nerve density was highly concentrated at the distal ureter in the adventitia and smooth muscle of the male and female human ureters. The female ureter had greater nerve density in the adventitia, and in smooth muscle nerves were significantly concentrated at the ureteral orifice and the ureteral tunnel.

Preoperative Computed Tomography Assessment for Perinephric Fat Invasion: Comparison With Pathological Staging.

OBJECTIVE: The aim of this study was to assess the accuracy of computed tomography (CT) imaging in diagnosing perinephric fat (PNF) invasion in patients with renal cell carcinoma. METHODS: We retrospectively reviewed the medical records and preoperative CT images of 161 patients (105 men and 56 women) for pT1-pT3a renal cell carcinoma. We analyzed the predictive accuracy of CT criteria for PNF invasion stratified by tumor size. We determined the predictive value of CT findings in diagnosing PNF invasion using logistic regression analysis. RESULTS: The overall accuracy of perinephric (PN) soft-tissue stranding, peritumoral vascularity, increased density of the PNF, tumoral margin, and contrast-enhancing soft-tissue nodule to predict PNF invasion were 56%, 59%, 35%, 80%, and 87%, respectively. Perinephric soft-tissue stranding and peritumoral vascularity showed high sensitivity but low specificity regardless of tumor size. A contrast-enhancing soft-tissue nodule showed low sensitivity but high specificity in predicting PNF invasion. Among tumors 4 cm or less, PN soft-tissue stranding showed 100% sensitivity and 70% specificity, and tumor margin showed 100% sensitivity and 98% specificity. Among CT criteria for PNF invasion, PN soft-tissue stranding was chosen as the only significant factor for assessing PNF invasion by logistic regression analysis. CONCLUSIONS: Computed tomography does not seem to reliably predict PNF invasion. However, PN soft-tissue stranding was shown to be the only significant factor for predicting PNF invasion, which showed good accuracy with high sensitivity and high specificity in tumors 4 cm or less.

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.

Predictability and Practicality of Image-Based Scoring Systems for Patient Assessment and Outcome Stratification During Percutaneous Nephrolithotomy: a Contemporary Update.

Preoperative nomograms offer systematic and quantitative methods to assess patient- and stone-related characteristics and their impact on successful treatment and potential risk of complication. Discrepancies in the correlation of perioperative variables to patient outcomes have led to the individual development, validation, and application of four independent scoring systems for the percutaneous nephrolithotomy: Guy's stone score, S.T.O.N.E. nephrolithometry, Clinical Research Office of the Endourology Society nomogram, and Seoul National University Renal Stone Complexity. The optimal nomogram should have high predictive ability, be practically integrated into clinical use, and be widely applicable to urinary stone disease. Herein, we seek to provide a contemporary evaluation of the advantages, disadvantages, and commonalities of each scoring system. While the current data is insufficient to conclude which scoring system is destined to become the gold standard, it is crucial that a nephrolithometric scoring system be incorporated into common practice to improve surgical planning, patient counseling, and outcome assessment.