Introduction: Percutaneous nephrolithotomy (PCNL) is the treatment of choice for kidney stones greater than 2 cm. ¹ This procedure in patients with obesity is challenging because obesity is a risk factor for complex access and requires more experience to achieve a successful puncture. ^{2 – 5} In this video, we demonstrate our technique for totally ultrasound-guided PCNL with two-step tract dilation, our experience, and provide guidance on improving success rates in patients with obesity. Materials and Methods: Surgical technique: With the patient in the supine position, we mobilized fatty tissue; after a proper ultrasound configuration, percutaneous access with a longitudinal freehand technique was obtained. Dilation with a two-step technique ⁶ Step 1: Creation of a minitract 14Fr to perform antegrade nephroscopy to check the renal cavities and measure the length of the tract; a pair of guides are placed in the ureter, one for definitive dilatation and the other as a safety guide. Step 2: Definitive tract 26Fr, insert the Amplatz dilator 1 cm in addition to the previously measured length of the tract to avoid a short dilation and advance the sheath. Pneumatic fragmentation is performed. Finally, a JJ stent was placed. Case series: Retrospective review of 54 patients treated with totally ultrasound-guided PCNL from July 2021 to June 2023, and we divided the cases according to their BMI: Group 1 included 27 patients with a BMI ≥30 kg/m2 and Group 2 included 27 patients with a normal BMI. Results: Mean age was 46.9 years. The BMI was 36.3 kg/m ² (±5.9) and 21.7 kg/m ² (±2.4) ( p = <0.001), respectively. In Group 1, 57% of our patients had Guy’s 3, and 15% had Guy’s 4; 72% of the cases had complex stones. The stone burden was 10,976.43 mm ³ (±11,287.6) and 7,543.0 mm ³ (±10,203.6) ( p = 0.056), with a mean of 12 cm and 8 cm of tract length ( p < 0.001), respectively ( Table 1 ). In the obesity group, the short dilation was more frequent, 63% vs. 26% ( p = 0.013). The stone-free rate was 77.8% in both groups ( p = 1.000), and we found that the stone burden had a more significant effect on the stone-free rate than the BMI ( Fig. 1 ). In Group 1, the complications were 3 (11.1%); 2 patients had fever (Clavien I), and 1 needed a blood transfusion due to anemia (Clavien II), whereas in Group 2 there were 6 (22.2%); 4 had fever (Clavien I), and 2 had urosepsis (Clavien IV) ( p = 0.019). FIG. 1. Relation between stone volume (mm ³ ) and body mass index (Kg/m ² ) in stone-free status: In blue , the patients with stone-free status, and in red , the patients with residual stone. Table 1. Preoperative and Postoperative Descriptive Data by Group according to BMI Total Group 1: BMI (≥30 kg/m ² ) Group 2: BMI (≤25 kg/m ² ) p Value Number of patients 54 27 27 Age, years 48.4 (±11.9) 49.9 (±11.1) 46.9 (±12.7) 0.36 Gender: n (%) Male 18 (33.3) 9 (33.3) 9 (33.3) 0.613 Female 36 (66.7) 18 (66.7) 18 (66.7) BMI (kg/m ² ) 29.06 (±27.7) 36.3 (±5.9) 21.7 (±2.4) <0.001 Previous Procedure: n (%) None 34 (62.9) 18 (66.7) 16 (59.3) 0.976 SWL 2 (3.7) 1 (3.7) 1 (3.7) Ureteral Stent 10 (18.5) 5 (18.5) 5 (18.5) Flexible Ureteroscopy 2 (3.7) 1 (3.7) 1 (3.7) PCNL 5 (9.2) 2 (7.4) 3 (11.1) Open Surgery 1 (1.8) 0 1 (3.7) Guy Stone: n (%) Guy 1 11 (20.3) 4 (14.8) 7 (25.9) 0.047 Guy 2 11 (20.3) 4 (14.8) 7 (25.9) Guy 3 20 (37) 15 (56.6) 5 (18.5) Guy 4 12 (22.2) 4 (14.8) 8 (29.6) Skin-stone distance (cm) 9.8 (±2.5) 11.7 (±2.0) 8.0 (±1.1) <0.001 Stone burden (mm ³ ) 9259.75 (±10797.2) 10976.43 (±11287.6) 7543.0 (±10203.6) 0.056 Hydronephrosis, n (%) None 34 (62.9) 19 (70.4) 15 (55.5) 0.494 Mild 10 (18.5) 3 (11.1) 7 (25.9) Moderate 10 (18.5) 5 (18.5) 5 (18.5) Tract number: n (%) One tract: 26Fr 44 (81.4) 22 (81.5) 22 (81.5) 1.000 Two tracts: 26Fr 9 (16.6) 5 (18.5) 4 (14.8) Three tracts: 26Fr 1 (1.85) 0 (0) 1 (3.7) Tract loss, n (%) Yes 4 (7.4) 2 (7.4) 2 (7.4) 1.000 No 50 (92.6) 25 (92.6) 25 (92.6) Short dilation, n (%) Yes 24 (44.4) 17 (63) 7 (25.9) 0.013 No 30 (55.4) 10 (37) 20 (74.1) Complications, Clavien– Dindo, n (%) Grade 1 6 (11.1) 2 (7.4) 4 (14.8) 0.019 Grade 2 1 (1.8) 1 (3.7) 0 Grade 3 0 0 0 Grade 4 2 (3.7) 0 2 (7.4) Hemoglobin drop (g/dL) 1.57 (±1.63) 1.62 (±1.71) 1.52 (±1.57) 0.986 Operative time (min) 137.4 (±60.7) 141.6 (±54.6) 133.1 (±67.0) 0.314 Stone free status, n (%) 42 (77.8) 21 (77.8) 21 (77.8) 1.000 p Value of t tests to compare means and Fisher’s exact test p value. Conclusion: A proper ultrasound configuration and adipose tissue mobilization increase success in obese patients. This technique offers a good stone-free rate and a safety profile without radiation. Rutime of video: 7 min 25 sec. No competing financial interests exist. Informed consent was obtained to film portions of the procedure from the patient who appeared in this video.

Introduction: The mini-perc technique was developed in 1997 to reduce trauma during percutaneous nephrolithotomy (PCNL) in children. ¹ The first ultrasound-guided mini-perc was performed in 1999 by Desai et al. ² Super mini PCNL (SMP) developed by Zeng et al. improves the mini-perc by using an irrigation–suction sheath that allows continuous suction of fragments and prevents excessive intrarenal pressure, improving observation and extraction of the stone. ³ Ultrasound-guided SMP has demonstrated a safe and effective treatment with the advantage of avoiding radiation. ⁴ Li et al. described the two-step dilation in standard ultrasound-guided PCNL ⁵ ; in this video, we describe the advantages of this technique in improving safety in SMP totally ultrasound-guided. Materials and Methods: Between July 2022 and July 2023, 15 patients underwent totally ultrasound-guided SMP with a two-step tract dilation. Surgical technique: In the Galdakao-modified Valdivia position, previous placement of a ureteral occlusion catheter, we adjusted the ultrasound parameters: gain, focus, depth, and dynamic range, and used an echogenic needle. ⁶ The access was obtained with a longitudinal freehand technique, obtaining urine indicates a successful puncture, an extra stiff guide was passed and sequential dilation (Step 1) with 10F to 12F to 14F fascial dilators; as it advances into the collector system, the dilator hides the guide and a plastic 14F peel-away sheath is placed (The plastic sheath does not create artifacts when observed with ultrasound, unlike metal sheaths, allowing better and safer control of dilation). An antegrade nephroscopy is performed to check the renal cavities and measure the length of the tract, and a pair of guides are placed in the ureter, one for definitive dilatation and the other as a safety guide. (Step 2): Placement of definitive metallic 14F irrigation–suction sheath (Hawk) under ultrasound control; insert 1 cm in addition to the previously measured length of the plastic sheath to avoid a short dilation; lithotripsy was performed with a 40 W holmium laser using fragmentation settings. The safety guidewire remains outside of the definitive sheath, and this enhances safety and prevents tract loss if the sheath is accidentally removed. Results: Dilation problems such as short dilation, tract loss, and collecting system injury were not encountered in any patient. The average age was 44 years, with a BMI of 28.3 ± 4.5 kg/m ² , with a predominance of left kidney stones in 53% of cases. The average stone burden was 2263 ± 1213 mm ³ (837 HU) the most frequent location was in the lower calix (46%). The mean operative time was 79 minutes (80–120). The lower calix was punctured in 53% with an average puncture time of 51 seconds. Because of the hypermobility of the lower pole, we migrated to routinely access the middle calyx. A single tract in 93% of cases, obtaining 93% stone free and totally tubeless in all cases. 80% of the procedures were ambulatory. The mean hemoglobin loss was 1.14 g/dL; only three patients had fever (Clavien I), and no other complications were recorded. Conclusions: This dilation technique appears to increase the safety of the procedure. SMP allows a good stone-free rate and can be an ambulatory and totally tubeless surgery. The study adhered to institutional review board protocols. Surgical videos were recorded with patient consent during routine care. Consent for video recording and publication of procedure was obtained and archived before the recording. No competing financial interests exist. Runtime of video: 8 mins 32 secs

Descripción del caso clínico: Masculino de 48 años con antecedente de enfermedad de las plaquetas gigantes y diagnóstico de riñón en herradura con litiasis renal, se realizó nefrolitotomía percutánea estándar 24Fr, se presentó 10 días posteriores al evento quirúrgico con hematuria macroscópica anemizante, formadora de coágulos, por lo que se sospecha de fístula arteriovenosa, se solicita valoración al servicio de cardiología intervencionista confirmando el diagnóstico y realizando embolización superselectiva en arteria segmentaria anterior y posterior, con resolución completa de la hematuria. Relevancia: Presentar una complicación poco frecuente de la nefrolitotomía percutánea como es la hematuria secundaria a fístula arteriovenosa en paciente con anomalía de la fusión renal resuelta mediante mínima invasión. Implicaciones clínicas: Tomar medidas en este grupo de pacientes para reducir esta complicación que puede poner en peligro la vida y el manejo mediante embolización superselectiva para evitar un deterioro de la función renal. Conclusiones: El acceso percutáneo guiado con ultrasonido y Doppler color puede permitir evitar la vasculatura renal durante la punción y el uso de tractos miniaturizados podría reducir el desarrollo de lesión a arterias segmentarias con posterior desarrollo de fistulas. La embolización es segura y efectiva en este grupo de pacientes.

Priapism is a partial or total erection which lasts more than 4 hours that occurs in the absence of sexual stimulation. It has an incidence rate of 1.5 per 100,000 people. It is classified as ischemic (low-flow) or non-ischemic (high-flow). Non-ischemic priapism is an atypical presentation characterized by a non-rigid erection without pain, and it is frequently associated with trauma. Our objective is to present this clinical case to highlight the importance of correctly classifying priapism types to provide appropriate treatment and avoid complications. A 37-year-old male with no history of chronic degenerative diseases. Patient's condition began with a morning erection followed by sexual activity. Patient came to the Emergency Room 5 days later since the erection persisted, which he reported was pain-free. He denied recent trauma or the use of erectile stimulants. High-flow priapism was diagnosed via Doppler ultrasound. Selective angioembolization was performed, achieving an immediate detumescence of 40%. Corporal blood gas testing is essential in the initial evaluation of any patient presenting with priapism. For high-flow priapism, conservative management should first be attempted; if priapism persists, embolization of the affected pudendal artery can be offered.