Selcuk Guven

Augmented reality: a new tool to improve surgical accuracy during laparoscopic partial nephrectomy? Preliminary in vitro and in vivo results.

BACKGROUND Use of an augmented reality (AR)-based soft tissue navigation system in urologic laparoscopic surgery is an evolving technique. OBJECTIVE To evaluate a novel soft tissue navigation system developed to enhance the surgeons perception and to provide decision-making guidance directly before initiation of kidney resection for laparoscopic partial nephrectomy (LPN). DESIGN, SETTING, AND PARTICIPANTS Custom-designed navigation aids, a mobile C-arm capable of cone-beam imaging, and a standard personal computer were used. The feasibility and reproducibility of inside-out tracking principles were evaluated in a porcine model with an artificially created intraparenchymal tumor in vitro. The same algorithm was then incorporated into clinical practice during LPN. INTERVENTIONS Evaluation of a fully automated inside-out tracking system was repeated in exactly the same way for 10 different porcine renal units. Additionally, 10 patients underwent retroperitoneal LPNs under manual AR guidance by one surgeon. MEASUREMENTS The navigation errors and image-acquisition times were determined in vitro. The mean operative time, time to locate the tumor, and positive surgical margin were assessed in vivo. RESULTS AND LIMITATIONS The system was able to navigate and superpose the virtually created images and real-time images with an error margin of only 0.5 mm, and fully automated initial image acquisition took 40 ms. The mean operative time was 165 min (range: 135-195 min), and mean time to locate the tumor was 20 min (range: 13-27 min). None of the cases required conversion to open surgery. Definitive histology revealed tumor-free margins in all 10 cases. CONCLUSIONS This novel AR tracking system proved to be functional with a reasonable margin of error and image-to-image registration time. Mounting the pre- or intraoperative imaging properties on real-time videoendoscopic images in a real-time manner will simplify and increase the precision of laparoscopic procedures.

Augmented reality visualization during laparoscopic radical prostatectomy.

PURPOSE We present an augmented reality (AR) navigation system that conveys virtual organ models generated from transrectal ultrasonography (TRUS) onto a real laparoscopic video during radical prostatectomy. By providing this additional information about the actual anatomy, we can support surgeons in their working decisions. This work reports the systems first in-vivo application. MATERIALS AND METHODS The system uses custom-developed needles with colored heads that are inserted into the prostate as soon as the organ surface is uncovered. These navigation aids are once segmented in three-dimensional (3D) TRUS data that is acquired right after the placement of the needles and then continuously tracked in the laparoscopic video images by the surgical navigation system. The navigation system traces the navigation aids in real time and computes a registration between TRUS image and laparoscopic video based on the two-dimensional-three dimensional (2D-3D) point correspondences. With this registration, the system correctly superimposes TRUS-based 3D information on an additional AR monitor placed next to the normal laparoscopic screen. Surgical navigation guidance took place until the prostate was removed from the rectal wall. Finally, the navigation aids were removed together with the specimen inside the specimen bag. RESULTS The initial human in-vivo application of the surgical navigation system was successful. No complications occurred, the prostate was removed together with the navigation aids, and the system supported the surgeons as intended with an AR visualization in real time. In case of tissue deformations, changes in the spatial configuration of the navigation aids are detected, which preserves the system from erroneous navigation visualization. CONCLUSIONS Feasibility of the navigation system was shown in the first in-vivo application. TRUS information could be superimposed via AR in real time. To show the benefit for the patient, results obtained from a larger number of trials are needed.

Successful percutaneous nephrolithotomy in children: multicenter study on current status of its use, efficacy and complications using Clavien classification.

PURPOSE In this multicenter study we aimed to evaluate the efficacy and safety of percutaneous nephrolithotomy in children with respect to different features and using the Clavien classification system. MATERIALS AND METHODS Percutaneous nephrolithotomies performed in children at 3 urology departments between March 2006 and May 2010 were included in the study. Results are presented for complex/simple renal stones, tubeless/totally tubeless percutaneous nephrolithotomy, simultaneous bilateral percutaneous nephrolithotomy, instrument size and age groups. Patients were divided into 3 distinct groups, infants and toddlers (3 years or younger, group 1), preschool children (4 to 7 years, group 2) and school children (8 to 16 years, group 3). Perioperative complications are presented according to the modified Clavien classification system. RESULTS A total of 140 percutaneous nephrolithotomies were performed in 130 patients (41.5% female, mean age 10.17 years). There were 23, 25 and 92 renal units in groups 1, 2 and 3, respectively. Pediatric instruments were used in 60 renal units and adult-sized instruments in 80. General assessment of complications showed Clavien grade I complications in 17 patients, II in 4, IIIa in 11 and IIIb in 7. There were no grade IV or V complications. CONCLUSIONS Percutaneous nephrolithotomy can be applied safely in children of varying ages, even infants. Complications, as assessed with Clavien classification, are comparable to those seen in adults provided there is enough experience with the technique.

Percutaneous Nephrolithotomy Is Highly Efficient and Safe in Infants and Children under 3 Years of Age

Objective: We aimed to evaluate the efficacy and safety of percutaneous nephrolithotomy (PNL) in infants and small children (12–36 months). Methods: The PNL applications conducted in children <3 years of age in two centers were evaluated. Whereas pediatric PNL instrumentation was used in the first center, adult-size instrumentation was utilized in the second center. The complications were given according to the modified Clavien classification system. Results: The mean age of the patients was 22.76 months (5–36 months) and the mean body weight was 11.51 kg (6–15 kg). In twelve renal units, pediatric instrumentation was used and among these, two had miniperc. In the other eight renal units, adult-size instrumentation was employed. Except for the patient with complex renal stones, all patients were stone free after the intervention and none required a conversion to open surgery. There were grade 1–2 complications in 3 patients. The postoperative hemoglobin drop was greater in the children who underwent PNL with adult-size instrumentation. Conclusion: In this young age group, in addition to standard PNL, simultaneous bilateral PNL, tubeless PNL and in urgent cases of renal failure, urgent PNL, are safe and effective treatment modalities provided patients are selected properly and the surgeon performing the procedure has the necessary experience.

Percutaneous nephrolithotomy in children in different age groups: data from the Clinical Research Office of the Endourological Society (CROES) Percutaneous Nephrolithotomy Global Study

Whats known on the subject? and What does the study add?

Totally tubeless percutaneous nephrolithotomy: is it safe and effective in preschool children?

BACKGROUND AND PURPOSE After the introduction of tubeless percutaneous nephrolithotomy (PNL), many studies conducted in adult patients have confirmed its efficacy and safety. There are limited studies reporting that tubeless PNL can be safely applied in children, however. Furthermore, there are no reports that evaluate the use of totally tubeless PNL in children. The present study evaluates the results of totally tubeless PNL in preschool children. PATIENTS AND METHODS The data of children seen in our clinic who were considered suitable for totally tubeless PNL were analyzed. Of 16 children, 8 patients underwent totally tubeless PNL (group 1) and 8 standard PNL (group 2). The two groups of patients were compared with regard to length of hospitalization, analgesic requirements, transfusion rates, hemoglobin (Hb) decrease, and immediate, early, and late complications. RESULTS The mean ages of the patients were 56.6 months (9-84 mos) and 56.0 months (5-84 mos), and the mean follow-up was 21.5 months (3-44 mos) and 43.4 months (36-54 mos) in groups 1 and 2, respectively. Both groups were similar with regard to age, stone size, Hb change, and complications. Although operation duration, hospitalization period, and analgesic requirement were less in the totally tubeless PNL group, these differences were not statistically significant. CONCLUSIONS The latest application of PNL, totally tubeless PNL, is also a safe and effective procedure in very small children if they are selected properly and if the surgeon has sufficient experience with the procedure. More studies with a higher number of participants are needed, however, to confirm that totally tubeless PNL increases the comfort of pediatric patients, decreases their hospitalization period, and is more economical.

Comparison of semen profile and frequency of chromosome aneuploidies in sperm nuclei of patients with varicocele before and after varicocelectomy

Semen profile and meiotic segregation products are important for assessing aneuploidy risk and risk of resulting infertility. To determine the effect of varicocelectomy on semen profile and aneuploidy frequency, we investigated semen profile and aneuploidy frequency of selected chromosomes in patients with varicocele before and after varicocelectomy. Chromosomal aneuploidy for selected chromosomes was evaluated using chromosome‐specific DNA fluorescence in situ hybridisation (FISH) probes. There was a significant difference in the level of normal sperm morphology before and after varicocelectomy (P > 0.007). There were no significant differences in aneuploidy frequency of chromosomes 1, 16, 17 and 18 in sperm nuclei obtained from patients before varicocelectomy compared with 6–7 months after varicocelectomy (P > 0.05), although FISH analysis with chromosomes 17 and 18 combination showed a higher aneuploidy frequency before varicocelectomy than after varicocelectomy (7.81 ± 9.67 versus 4.03 ± 1.46 respectively). In conclusion, varicocele seems to affect the semen profile but minimally affects aneuploidy frequency. Varicocelectomy demonstrates a repairing effect on the semen profile and contributes to a slight decrease in aneuploidy frequency in some but not all chromosomes.

Partial priapism secondary to tamsulosin: a case report and review of the literature.

Partial priapism is also called partial segmental thrombosis of the corpus cavernosum. It is a rare pathology, and its aetiology, physiopathology and treatment are still not completely understood. To our knowledge, partial priapism due to alpha blockers has not been reported previously in the literature. In this study, a successfully treated case of partial priapism occurring after the usage of alpha blocker is presented and discussed in light of the related literature.

Management of a Colon Perforation During Pediatric Percutaneous Nephrolithotomy

Percutaneous nephrolithotomy (PCNL) is one of the most common treatment options in the management of kidney stones in children. While colon perforation during PCNL is reported as a rare complication in adults, there are scarce data regarding colon perforation during pediatric PCNL. We report the successful management of colon perforation occurring during PCNL and of a renal stone in a 6-year-old child. Moreover, we describe the procedure to be followed for colon perforation in children.

In-Vitro Evaluation of a Soft-Tissue Navigation System for Laparoscopic Prostatectomy

PURPOSE We introduce a custom-designed phantom model for the in-vitro evaluation of an augmented reality-based soft-tissue navigation system for ultrasound-guided prostate interventions. MATERIALS AND METHODS Transrectal ultrasound segmentation of the prostate, navigation aid placement, initial registration, endoscope tracking, and enhanced visualization steps in the navigation procedure were performed to accommodate the actual prostatic motion. In-vitro laparoscopic manipulations simulating surgical procedures were performed by a physician using human prostate specimens. The target visualization error, defining the accuracy of the tracking, is determined by means of a leave-out test strategy by alternately using four navigation aids for endoscope registration and the remaining two navigation aids for accuracy verification. RESULTS The introduction of the navigation aids lasted approximately 3 minutes. The navigation aids and especially their barbs were visible because of their ultrasound reflecting nature. For each organ, 1000 endoscope registrations were calculated, in which two randomly chosen navigation aids served the purpose of verifying the pose. We were able to demonstrate that the superimposed image could follow automatically the videoendoscopic real-time view. The mean target visualization errors for the respective trials were determined as 0.81 (±0.12) mm, 0.62 (±0.14) mm, and 0.98 (±0.23) mm. CONCLUSIONS The ultrasound-based inside-out navigation system for laparoscopic prostatectomy overcomes the problem of tissue shift and deformation in an in-vitro model. In case of organ movement, the augmented picture with the detected navigation aids could follow the videoendoscopic image using the navigation aids as landmarks.