Understanding the ablation rate of Holmium:YAG and thulium fiber lasers. Perspectives from an in vitro study.

This study sought to analyze the ablation rates of Holmium:YAG (Ho:YAG) and thulium fiber laser (TFL) under different settings combinations. Lasering was carried out by a computed spiral pattern through a stepper motor bearing a laser fiber. BegoStones were placed inside a water container and lasered therein and the ablation rate was calculated. Different combinations were tested for ~12 Watts (W) for Ho:YAG and TFL lasers. Further 25 W combination for TFL were conducted testing higher frequencies. One-hundred-one experiments were conducted. Under ~12 W, the highest ablation rate for Ho:YAG was obtained with 40 Hz/0.3 J, and Virtual Basket™ (VB) emission mode [114.35 (88.30 - 126.40) mg/min] whereas for TFL, using 40 Hz/0.3 J, and long pulse [143.40 (137.40 - 146) mg/min]. A matched-comparison for 12 Hz/1 J settings showed that TFL outperformed Ho:YAG using medium pulse [63.30 (55.30 - 81.30) vs 132.00 (115.70 - 228.60) mg/min, p=0.016] and long pulse [62.90 (51.60 - 78.90) vs 134.70 (110.60 - 149.30) mg/min, p=0.016]. In the 40 Hz/0.3 J settings, TFL outperformed Ho:YAG (p=0.034). Nonetheless, Ho:YAG with VB's ablation rate increased [114.35 (88.30 - 126.40)], being comparable to that of TFL with medium pulse [127.5 (88.90 - 141.70)] (p=0.400). In TFL 25 W experiments, the ablation rate of 500 Hz / 0.05 J, was higher than those of 1000 Hz / 0.025 J (p=0.049). TFL ablation rate is higher than that of Ho:YAG. Moreover, the Virtual Basket™ emission mode, increased Ho:YAG ablation rates, resulting reaching similar to that of TFL in certain modalities.

Can we omit systematic biopsies in patients undergoing MRI fusion-targeted prostate biopsies?

Magnetic resonance imaging (MRI)-targeted prostate biopsy is the recommended investigation in men with suspicious lesion(s) on MRI. The role of concurrent systematic in addition to targeted biopsies is currently unclear. Using our prospectively maintained database, we identified men with at least one Prostate Imaging-Reporting and Data System (PI-RADS) ≥3 lesion who underwent targeted and/or systematic biopsies from May 2016 to May 2020. Clinically significant prostate cancer (csPCa) was defined as any Gleason grade group ≥2 cancer. Of 545 patients who underwent MRI fusion-targeted biopsy, 222 (40.7%) were biopsy naïve, 247 (45.3%) had previous prostate biopsy(s), and 76 (13.9%) had known prostate cancer undergoing active surveillance. Prostate cancer was more commonly found in biopsy-naïve men (63.5%) and those on active surveillance (68.4%) compared to those who had previous biopsies (35.2%; both P < 0.001). Systematic biopsies provided an incremental 10.4% detection of csPCa among biopsy-naïve patients, versus an incremental 2.4% among those who had prior negative biopsies. Multivariable regression found age (odds ratio [OR] = 1.03, P = 0.03), prostate-specific antigen (PSA) density ≥0.15 ng ml-2 (OR = 3.24, P < 0.001), prostate health index (PHI) ≥35 (OR = 2.43, P = 0.006), higher PI-RADS score (vs PI-RADS 3; OR = 4.59 for PI-RADS 4, and OR = 9.91 for PI-RADS 5; both P < 0.001) and target lesion volume-to-prostate volume ratio ≥0.10 (OR = 5.26, P = 0.013) were significantly associated with csPCa detection on targeted biopsy. In conclusion, for men undergoing MRI fusion-targeted prostate biopsies, systematic biopsies should not be omitted given its incremental value to targeted biopsies alone. The factors such as PSA density ≥0.15 ng ml-2, PHI ≥35, higher PI-RADS score, and target lesion volume-to-prostate volume ratio ≥0.10 can help identify men at higher risk of csPCa.

Simultaneous Bilateral Endoscopic Surgery (SBES): Is It Ready for Prime Time?

Introduction: To date, some data available in literature on simultaneous bilateral endoscopic surgery (SBES) have shown good outcomes in terms of both effectiveness and safety. The aim of this study was to report the outcomes pertaining to the effectiveness and safety of SBES performed in our series of patients with bilateral renal stones. Materials and Methods: A prospective analysis of consecutive patients who underwent SBES for bilateral renal stones at our institution between June 2017 and September 2021 was performed. Routine preoperative and 1-month postoperative work-up included history, physical examination, urinalysis, urine culture, and blood tests, including the evaluation of estimated glomerular filtration rate using the Cockcroft-Gault equation. An abdominal noncontrast CT scan was performed in all cases preoperatively and 1 month postoperatively. Peri-/postoperative complications were reported according to the Clavien-Dindo classification system. The primary endpoint of the study was stone-free rate (SFR), and the secondary endpoints were Clavien-Dindo complications grade 1 or higher. Results: Altogether, 101 patients met the inclusion criteria and were enrolled in the study. SFR for all renal units was achieved in 82 patients (81.1%) at the 1-month follow-up. Twelve patients underwent additional flexible ureteroscopy for residual fragments, and 7 asymptomatic patients with single small residual fragment were observed. Eighteen patients (17.8%) experienced Clavien-Dindo Grade I-II complications, whereas one patient (1%) experienced Clavien-Dindo Grade IIIa complication (renal arteriovenous fistula embolization under local anesthesia). Conclusions: SBES is a safe and effective procedure for the treatment of bilateral renal stones. Further randomized studies with larger populations are needed to confirm these favorable outcomes of SBES to establish it as an alternative to staged surgeries in patients with bilateral renal stones. Appropriate patient selection is of paramount importance for achieving good outcomes without experiencing severe complications.

Is emergency right hemicolectomy still associated with significant morbidity and mortality rates? An institution's experience of 207 cases over 6 years.

INTRODUCTION: Emergency right hemicolectomy has been associated with dismal outcome. But, data in Asians is lacking as pathologies that require emergency right hemicolectomy may differ from that in the Western population. The aims of our study were to review our institution's experience with emergency right hemicolectomies and to identify factors that could predict the per-operative outcome. METHODS: A retrospective review of all patients who underwent emergency right hemicolectomy from August 2003 to April 2008 was performed. Emergency right hemicolectomy was defined as a right colectomy, comprising of an ileo-colic resection, in the emergency setting without the benefit of preoperative bowel preparation. All the complications were graded according to the classification proposed by Clavien and group. RESULTS: A total of 207 patients, median age 62 years (range, 19-94 years), underwent emergency right hemicolectomy during the study period. Neoplasia and complicated diverticular disease were the most common pathologies in 46.4% and 21.7%, respectively. Intestinal obstruction (44.4%) and perforation (26.6%) were the two main indications for surgical intervention in our series. Twenty (9.7%) patients died, and another 39 patients (18.8%) had severe complications. Eight (3.9%) patients had anastomotic dehiscence, while burst abdomen was seen in ten (4.8%) patients. The two independent factors associated with worse outcome were high ASA score and stoma creation. Factors such as age and site of perforation were not related. CONCLUSION: Emergency right hemicolectomy is associated with a significant morbidity and mortality rate. Patients with higher ASA score and who had stoma created fared worse.

Thulium:YAG Versus Holmium:YAG Laser Effect on Upper Urinary Tract Soft Tissue: Evidence from an Ex Vivo Experimental Study.

Introduction: There are limited data regarding the effect of thulium laser (Tm:YAG) and holmium laser (Ho:YAG) on upper urinary tract. The aim of this study was to compare soft tissue effects of these two lasers at various settings, with a focus on incision depth (ID) and coagulation area (CA). Materials and Methods: An ex vivo experimental study was performed in a porcine model. The kidneys were dissected to expose the upper urinary tract and the block samples containing urothelium and renal parenchyma were prepared. The laser fiber, fixed on a robotic arm, perpendicular to the target tissue was used with a 100 W Ho:YAG and a 200 W Tm:YAG. Incisions were made with the laser tip in contact with the urothelium and in continuous movement at a constant speed of 2 mm/s over a length of 1.5 cm. Total energy varied from 5 to 30 W. Incision shape was classified as follows: saccular, triangular, tubular, and irregular. ID, vaporization area (VA), CA, and total laser area (TLA = VA + CA) were evaluated. Statistical analysis was performed using the SPSS V23 package, p-values <0.05 were considered statistically significant. Results: A total of 216 experiments were performed. Incision shapes were saccular (46%), triangular (38%), and irregular (16%) with the Ho:YAG, while they were tubular (89%) and irregular (11%) with the Tm:YAG. ID was significantly deeper with the Ho:YAG (p = 0.024), while CA and TLA were larger with the Tm:YAG (p < 0.001 and p < 0.005). Conclusion: ID was deeper with Ho:YAG, whereas CA and TLA were larger with the Tm:YAG. Considering surgical principles for endoscopic ablation of upper tract urothelial carcinoma, these results suggest that Tm:YAG may have a lower risk profile (less depth of incision) while also being more efficient at tissue destruction. Future in vivo studies are necessary to corroborate these findings.

Holmium laser for RIRS. Watts are we doing? / Laser holmium para ureteroscopia flexible retrograda. ¿Qué estamos haciendo?

OBJECTIVE: To review recent and relevant information regarding the use of high-power (HPL) and low-power (LPL) Holmium:YAG lasers (Ho:YAG) in retrograde intrarenal surgery (RIRS) for lithotripsy. METHODS: A PubMed/Embase search was conducted and recent and relevant papers on Ho:YAG for RIRS were reviewed. RESULTS: Settings for Ho:YAG are pulse energy (PE), pulse frequency (PF), and pulse width. Currently, the majority of LPL can also adjust pulse-width but cannot reach PF as high as HPL, however, the higher energy outputs reached by HPL are rarely useful in lithotripsy. Higher PE might enhance ablation but generates larger fragments and higher retropulsion. Pulse width does not affect energy output but delivers energy for a longer time-length. Dusting and basketing are complementary techniques. Dusting seeks to pulverize stones into particles ≤250 µm avoiding the use of instruments for stone retrieval, whereas in fragmenting, the stones are break into smaller pieces which are then retrieved. Dusting can prevent the use of supplies such as access sheaths and baskets and also prevent the complications related to their use. However, is not always feasible in clinical practice to fully ablate a stone into dust, then the use of this supplies and popcorn technique are helpful for rendering a patient stonefree. The energy gap between HPL and LPL is wide and leaves room for a mid-power laser classification, which can overcome the main drawback of LPL, the expenses of HPL, and still holding its versatility for other procedures beyond stones. CONCLUSIONS: HPL and LPL have similar effectiveness, but long-term cost-effectiveness comparisons are underexplored. Newer HPL would need to be compared to emerging technologies as the thulium fiber, and prove superiority to mid-power laser to determine how powerful is enough for Ho:YAG in the years to come.

OBJETIVO: El láser Holmio:YAG (Ho:YAG) es el de elección para litotricia en cirugía retrógrada intrarenal (RIRS). Los equipos láser de alto poder (HPL) y bajo poder (LPL) tienen diferentes características, por lo tanto, pueden tener diferente desempeño. En el presente trabajo tuvimos el objetivo de revisar evidencia sobre el uso de HPL y LPL en RIRS. MATERIAL Y MÉTODOS: Se realizó una búsqueda en PubMed/Embase y la información reciente y relevante sobre HPL y/o LPL en RIRS fue evaluada para una revisión monográfica. RESULTADOS: Los HPL y algunos LPL más recientes permiten al cirujano ajustar la duración del pulso, por lo tanto, al configurar un pulso largo, alta frecuencia y baja energía, se puede lograr una verdadera pulverización. Los LPL no pueden alcanzar la misma emisión de energía que los HPL. La retropulsión aumenta si la energía de pulso es mayor, entonces, se previene la retropulsión al incrementar la emisión total de energía mediante el incremento de la frecuencia. El costo de adquisión de los HPL es considerablemente mayor que el de los LPL, sin embargo, el costo a largo plazo pudiera ser similar pues los procedimientos pueden abaratarse al disminuir el uso de insumos para recuperar los litos, preservar la punta de las fibras reutilizables y disminuir el tiempo quirúrgico. CONCLUSIONES: La evidencia no favorece la efectividad de los HPL o LPL de modo abrumador. Ambos dispositivos son efectivos y seguros. No cabe duda de que los HPL alcanzan mayor emisión de energía que los LPL, pero los dispositivos de 50-80 Watts, tienen emisiones de energía que rara vez se alcanzan para litotricia y por lo tanto pudiera considerarse demasiada energía. A medida que nuevas tecnologías han surgido, la brecha entre LPL y HPL se amplía, dejando espacio para una clasificación de poder intermedio (36-55 Watts) y la comparación entre estos dispositivos sería más justa. Asimismo, los HPL aún necesitan ser contrastados en el escenario clínico, con las nuevas tecnologías disponibles, tal como la fibra de laser tulio.

Endourologic Treatment of Late Migration of Embolization Causing Nephrolithiasis in Two Patients.

Background: Selective renal artery angioembolization is the first treatment option in case of significant bleeding after percutaneous nephrolithotomy. Migration of embolization material into the collecting system is extremely rare. The treatment of this condition is not standardized, but manual extraction, ultrasound fragmentation, and holmium laser lithotripsy have been described. Case presentation: We report the laser extraction of these coils in two patients at our center with two different approaches: retrograde intrarenal surgery (RIRS) and endoscopic combined intrarenal surgery (ECIRS). They were young male patients aged 25 and 29 years at the time of surgery, and they were 2-5 years postembolization when they presented to our center for symptoms such as hematuria and passage of small stone fragments. The first patient was managed solely with RIRS, whereas the second patient required ECIRS because of significant bleeding after coil removal, which necessitated hemostasis using a resectoscope. Conclusion: For patients who present with recurrent stones or other symptoms such as pain, hematuria, or flank pain, the diagnosis of migrated embolization coils should be considered. Management can be via the retrograde or percutaneous approach, but in the setting of significant amount of migrated coils or significant bleeding after their removal, percutaneous access may allow more definitive hemostasis.

MRI Fusion-Targeted Transrectal Prostate Biopsy and the Role of Prostate-Specific Antigen Density and Prostate Health Index for the Detection of Clinically Significant Prostate Cancer in Southeast Asian Men.

OBJECTIVE: To test the hypothesis that targeted biopsy has a higher detection rate for clinically significant prostate cancer (csPCa) than systematic biopsy. We defined csPCa as any Gleason sum ≥7 cancer. In patients with Prostate Imaging Reporting and Data System (PI-RADS) 3 lesions, to determine if factors, such as prostate-specific antigen density (PSAD) and prostate health index (PHI), can predict csPCa and help select patients for biopsy. MATERIALS AND METHODS: We report the first series of targeted biopsies in Southeast Asian men, with comparison against systematic biopsy. Consecutive patients were registered into a prospective institutional review board-approved database in our institution. We reviewed patients who underwent biopsy from May 2016 to June 2017. Inclusion criteria for our study were patients with at least one PI-RADS ≥3, and who underwent both targeted and systematic biopsies in the same sitting. RESULTS: There were 115 patients in the study, of whom 74 (64.3%) had a previous negative systematic biopsy. Targeted biopsies detected significantly less Gleason 6 cancers than systematic biopsies (p < 0.01), and demonstrated significantly higher sensitivity, specificity, positive predictive value, and negative predictive value (NPV) for the detection of csPCa. For patients with PI-RADS 3 lesions, PHI and PSAD were found to be the best predictors for csPCa. PSAD <0.10 ng/mL/mL had an NPV of 93% and sensitivity of 92%, while allowing 20% of patients to avoid biopsy. PHI cutoff of <27 would allow 34% of patients to avoid biopsy, with both sensitivity and NPV of 100%. CONCLUSIONS: Targeted prostate biopsies were found to be significantly superior to systematic biopsies for the detection of csPCa, while detecting less Gleason 6 cancer. Usage of PSAD and PHI cutoff levels in patients with PI-RADS 3 lesions may enable a number of patients to avoid unnecessary biopsy.

Xanthogranulomatous pyelonephritis presenting as Proteus preperitoneal abscess.

Xanthogranulomatous pyelonephritis (XGPN) is a rare form of chronic pyelonephritis with progressive loss of renal function. Commonly, obstructing urinary calculi are seen. It is difficult to differentiate between XGPN and malignancy in many cases, and the diagnosis is usually only confirmed post-operatively upon histopathological examination of the specimen. Surgical treatment is often the main treatment modality due to suspicion for malignancy. Here, we present a case of XGPN that presented with abdominal distension, which was eventually discovered to be due to a preperitoneal abscess.