Tissue effects of a newly developed diode pumped pulsed Thulium:YAG laser compared to continuous wave Thulium:YAG and pulsed Holmium:YAG laser.

PURPOSE: The objective of this study is to evaluate the laser-tissue effects of laser radiation emitted by a newly developed high frequency pulsed Tm:YAG laser in comparison to the continuous wave Tm:YAG laser and the pulsed Ho:YAG laser. METHODS: Ex-vivo experiments were performed on freshly slaughtered porcine kidneys in a physiological saline solution. Experiments were performed using two different laser devices in different settings: A Tm:YAG laser was operated in a pulsed mode up to 300 Hz and in a continuous wave (CW) mode. Results were compared with a 100 W standard pulsed Ho:YAG laser system. Comparative tissue experiments were performed at 5 W, 40 W and 80 W. The incision depth and the laser damage zone were measured under a microscope using a calibrated ocular scale. RESULTS: Increased laser power resulted in increased incision depth and increased laser damage zone for all investigated lasers in this set-up. The Ho:YAG created the largest combined tissue effect at the 5 W power setting and seems to be the least controllable laser at low power for soft tissue incisions. The CW Tm:YAG did not incise at all at 5 W, but created the largest laser damage zone. For the new pulsed Tm:YAG laser the tissue effect grew evenly with increasing power. CONCLUSION: Among the investigated laser systems in this setting the pulsed Tm:YAG laser shows the most controllable behavior, insofar as both the incision depth and the laser damage zone increase evenly with increasing laser power.

Miniaturization of percutaneous nephrolithotomy Smaller, but better?

PURPOSE OF REVIEW: Miniaturized percutaneous nephrolithotomy (PCNL) procedures have reached big popularity in the past years. Following the idea that decreasing the diameter of the instruments would decrease the complication rate instruments with outer diameter down to 4,8 Fr was established. In this review, we want to take a critical insight of the most popular miniaturized procedures, regarding the key advantages and disadvantages of the miniaturized instruments. RECENT FINDINGS: For all techniques displayed, a number of studies are available to support their effectivity in the given range of indication. Naturally, the body of evidence for M-sized instruments is largest, as it exists in the armamentarium since long, whereas studies comparing small or extrasmall and extraextrasmall to standard or among each other are rare. However, large studies comparing miniaturized procedures with conventional PCNL in randomized controlled fashion are still lacking, too. SUMMARY: Miniaturization and attending developments such as ultrasonographic-guided puncture, single step dilatation of the tract, low irrigation pressure in open systems and a tubeless procedure lead to lower complication rates in PCNL. All of the established procedures have their own range of indication with regard to size and location of the stone. They amplified the possibility of a customized therapy for each patient.

SOCIUS Mentoring-A Novel Course to Encourage Students for a Career as Surgical Oncologists.

Surgical disciplines are affected by an increasing shortage of young doctors. Studies show that formerly interested students decide against a career in surgical disciplines at the end of their studies or during practical year. Measures to counteract this development are urgently needed. As a joint project between gynecology, urology, and general surgery, SOCIUS mentoring was designed to prepare and encourage students for a career in surgical oncology. The structured curriculum of SOCIUS mentoring contains six modules, including surgical skills, soft skills, mentoring, theory, clinical visitation, and congress participation and runs over one year. Effects on confidence towards physician skills and plans for a future career were evaluated with questionnaires. After participation, students reported increased confidence in surgical and soft skills. In addition, participants noted that they have specified their career goals and gained more confidence in surgery, as well as seeing more development potential for a career in surgery. We describe the implementation of a novel extracurricular program for motivated students that combines individual mentoring with surgical and soft skills training. Due to its modular structure, this concept can easily be transferred to other disciplines. SOCIUS mentoring, with its combination of mentoring and skills training, is a promising measure to prepare and motivate students for their surgical career and thus counteract the shortage of young talent.

Impact of Surgical Experience Before Robot-assisted Partial Nephrectomy on Surgical Outcomes: A Multicenter Analysis of 2500 Patients.

Background: Robot-assisted partial nephrectomy (RAPN) is a challenging procedure that is influenced by a multitude of factors. Objective: To assess the impact of prior surgical experience on perioperative outcomes in RAPN. Design setting and participants: In this retrospective multicenter study, results for 2548 RAPNs performed by 25 surgeons at eight robotic referral centers were analyzed. Perioperative data for all consecutive RAPNs from the start of each individual surgeon's experience were collected, as well as the number of prior open or laparoscopic kidney surgeries, pelvic surgeries (open, laparoscopic, robotic), and other robotic interventions. Intervention: Transperitoneal or retroperitoneal RAPN. Outcome measurements and statistical analysis: The impact of prior surgical experience on operative time, warm ischemia time (WIT), major complications, and margin, ischemia, complication (MIC) score (negative surgical margins, WIT ≤20 min, no major complications) was assessed via univariate and multivariable regression analyses accounting for age, gender, body mass index (BMI), American Society of Anesthesiologists score, PADUA score, and RAPN experience. Results and limitations: BMI, PADUA score, and surgical experience in RAPN had a strong impact on perioperative outcomes. A plateau effect for the learning curve was not observed. Prior laparoscopic kidney surgery significantly reduced the operative time (p < 0.001) and WIT (p < 0.001) and improved the MIC rate (p = 0.022). A greater number of prior robotic pelvic interventions decreased WIT (p = 0.011) and the rate of major complications (p < 0.001) and increased the MIC rate (p = 0.011), while prior experience in open kidney surgery did not. One limitation is the short-term follow-up. Conclusions: Mastering of RAPN is an ongoing learning process. However, prior experience in laparoscopic kidney and robot-assisted pelvic surgery seems to improve perioperative outcomes for surgeons when starting with RAPN, while experience in open surgery might not be crucial. Patient summary: In this multicenter analysis, we found that a high degree of experience in keyhole kidney surgery and robot-assisted pelvic surgery helps surgeons in achieving good initial outcomes when starting robot-assisted kidney surgery.

[Pressure study of two miniaturised amplatz sheaths of 9.5 F and 12 F outer diameter for minimal invasive percutaneous nephrolithotomy (MIP): An ex vivo organ model measurement]. / Druckverhältnisse bei Verwendung miniaturisierter PNL-Schäfte mit 9,5 Ch bzw. 12 Ch Außendurchmesser für die minimalinvasive perkutane Nephrolitholapaxie (MIP): Ex-vivo-Druckstudien.

Over the last decade, several devices for percutaneous nephrolithotomy with smaller diameters have been introduced in order to reduce renal trauma. Recent studies have found comparable stone free rates but also exhibit the same rate of postoperative fever and septicaemia. One possible cause is the influence of irrigation fluid during stone treatment procedures. The purpose of this ex vivo study was to compare two new miniaturised PNL nephroscopy sheaths with an outer sheath diameter of 9.5 F and 12 F to the well-established MIP M Set (17.5 F) by Karl Storz. MATERIAL AND METHODS: The new devices were tested in a perfused organ model of fresh porcine kidneys with different irrigation pressures, applied either by gravitation or the use of a pressure pump (Uromat E.A.S.I. Pump, Karl Storz, Tuttlingen, Germany).In addition, the 9.5 F sheath was examined for active irrigation evacuation, i. e. suction of irrigation fluid through a mono-J-catheter. An urodynamic pressure probe measured intrapelvic pressure levels throughout the procedures. RESULTS: Regardless of the sheath diameters used, the intrapelvic pressure did not exceed 40 cmH2O (30 mmHg) when applying moderate irrigation pressure levels, either by pump or gravitation. The active suction of irrigation fluid from the kidney basin via the mono-J-catheter had no measurable impact on the detected intrarenal pressures. A crucial increase in the intrapelvic pressure was detected only when using the 9.5 F sheath in combination with applying high irrigation pressures. CONCLUSION: The newly designed miniaturised MIP sets maintain the favourable pressure features of the earlier 17.5 MIP sheath. Although the diameter has been reduced to 12F or 9.5 F, the intrapelvic pressures remained below 40 cmH2O when regular irrigation settings by gravitation or pump irrigation were used.

Tissue damage by laser radiation: an in vitro comparison between Tm:YAG and Ho:YAG laser on a porcine kidney model.

The understanding of tissue damage by laser radiation is very important for the safety in the application of surgical lasers. The objective of this study is to evaluate cutting, vaporization and coagulation properties of the 2 µm Tm:YAG laser (LISA Laser Products OHG, GER) in comparison to the 2.1 µm Ho:YAG laser (Coherent Medical Group, USA) at different laser power settings in an in vitro model of freshly harvested porcine kidneys. Laser radiation of both laser generators was delivered by using a laser fiber with an optical core diameter of 550 µm (RigiFib, LISA Laser GER). Freshly harvested porcine kidneys were used as tissue model. Experiments were either performed in ambient air or in aqueous saline. The Tm:YAG laser was adjusted to 5 W for low and 120 W for the high power setting. The Ho:YAG laser was adjusted to 0.5 J and 10 Hz (5 W average power) for low power setting and to 2.0 J and 40 Hz (80 W average power) for high power setting, accordingly. The specimens of the cutting experiments were fixed in 4 % formalin, embedded in paraffin and stained with Toluidin blue. The laser damage zone was measured under microscope as the main evaluation criteria. Laser damage zone consists of an outer coagulation zone plus a further necrotic zone. In the ambient air experiments the laser damage zone for the low power setting was 745 ± 119 µm for the Tm:YAG and 614 ± 187 µm for the Ho:YAG laser. On the high power setting, the damage zone was 760 ± 167 µm for Tm:YAG and 715 ± 142 µm for Ho:YAG. The incision depth in ambient air on the low power setting was 346 ± 199 µm for Tm:YAG, 118 ± 119 µm for Ho:YAG. On the high power setting incision depth was 5083 ± 144 µm (Tm:YAG) and 1126 ± 383 µm (Ho:YAG) respectively. In the saline solution experiments, the laser damage zone was 550 ± 137 µm (Tm:YAG) versus 447 ± 65 µm (Ho:YAG), on the low power setting and 653 ± 137 µm (Tm:YAG) versus 677 ± 134 µm (Ho:YAG) on the high power setting. Incision depth was 1214 ± 888 µm for Ho:YAG whereas Tm:YAG did not cut tissue at 5 W in saline solution. On the high power setting, the incision depth was 4050 ± 1058 µm for Tm:YAG and 4083 ± 520 µm for Ho:YAG. Both lasers create similar laser damage zones of <1 mm in ambient air and in saline solution. These in vitro experiments correspond well with in vivo experiments. Thereby, Tm:YAG offers a cutting performance, coagulation and safety profile similar to the standard Ho:YAG lasers in urological surgery.