Point Of Maximum Curvature Research Articles

MP33-05 MULTI-CENTER EXPERIENCE UTILIZING COLLAGEN FLEECE FOR PLAQUE INCISION WITH GRAFTING AT TIME OF INFLATABLE PENILE PROSTHESIS PLACEMENT IN PEYRONIE’S DISEASE PATIENTS

You have accessJournal of UrologySexual Function/Dysfunction: Peyronie's Disease (MP33)1 Apr 2020MP33-05 MULTI-CENTER EXPERIENCE UTILIZING COLLAGEN FLEECE FOR PLAQUE INCISION WITH GRAFTING AT TIME OF INFLATABLE PENILE PROSTHESIS PLACEMENT IN PEYRONIE’S DISEASE PATIENTS David Yang*, Georgios Hatzichristodoulou, Kevin Hebert, Joshua Ring, Matthew Ziegelmann, and Tobias Kohler David Yang*David Yang* More articles by this author , Georgios HatzichristodoulouGeorgios Hatzichristodoulou More articles by this author , Kevin HebertKevin Hebert More articles by this author , Joshua RingJoshua Ring More articles by this author , Matthew ZiegelmannMatthew Ziegelmann More articles by this author , and Tobias KohlerTobias Kohler More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000877.05AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Plaque incision and grafting (PIG) is often necessary to correct residual curvature during IPP placement in patients with severe Peyronie’s Disease (PD). We present our multi-center experience using sutureless collagen fleece grafting with IPP placement in patients with severe PD. METHODS: We retrospectively reviewed IPP patients from 3 sites who underwent PIG with Tachosil® (Baxter, IL, USA) collagen fleece. Coloplast (Humlebaek, Denmark) IPP devices were used. Initially, a subcoronal incision is made. After IPP placement, the point of maximum curvature is marked. The neurovascular bundles are lifted, and an incision with cautery is made through the scar. The exposed device is covered with the collagen fleece, and the neurovascular bundles are re-approximated. The device is left 70% inflated for 3 weeks. The patient avoids sexual activity for 6 weeks. Factors associated with residual curvature, revision and patient satisfaction was performed using chi-squared analysis. RESULTS: Fifty one patients met inclusion criteria. The average compound curvature was 69.6 degrees. 80% of patients had a dorsal component to their curvature. Only two patients had a ventral curvature requiring urethral mobilization. Surgical outcomes are reported in Table 1. Briefly, all patients reported a functional erection at last follow up. Six patients noted residual curvature of less than 15 degrees, and only pre-operative curvature >60 degrees was associated with residual curvature. Post-operative complications requiring revision were minimal. CONCLUSIONS: PIG utilizing collagen fleece is a safe and effective means of correcting residual curvature after IPP placement. In our multi-centered study, patients experienced substantial curve correction with minimal complications. In the few patients that had persistent mild curvature, severe preoperative curvature (>60 degrees) was found to be the only risk factor. Source of Funding: none © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e496-e496 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information David Yang* More articles by this author Georgios Hatzichristodoulou More articles by this author Kevin Hebert More articles by this author Joshua Ring More articles by this author Matthew Ziegelmann More articles by this author Tobias Kohler More articles by this author Expand All Advertisement PDF downloadLoading ...

Modified Distance Transformation for ImageEnhancement in NIR Imaging of Finger Vein System.

Most of the current image processing methods used in the near-infrared imaging of finger vascular system concentrate on the extraction of internal structures (veins). In this paper, we propose a novel approach which allows to enhance both internal and external features of a finger. The method is based on the Distance Transformation and allows for selective extraction of physiological structures from an observed finger. We evaluate the impact of its parameters on the effectiveness of the already established processing pipeline used for biometric identification. The new method was compared with five state-of-the-art approaches to features extraction (position-gray-profile-curve—PGPGC, maximum curvature points in image profiles—MC, Niblack image adaptive thresholding—NAT, repeated dark line tracking—RDLT, and wide line detector—WD) on the GustoDB database of images obtained in a wide range of NIR wavelengths (730–950 nm). The results indicate a clear superiority of the proposed approach over the remaining alternatives. The method managed to reach over identification accuracy for all analyzed datasets.

Accuracy, inter-observer and intra-observer reliability in topography assessment of multifocal contact lens centration

PurposeTo evaluate the accuracy and reliability (inter and intra-observer) of a method to assess multifocal contact lenses (MCLs) centration using a corneal topography unit. MethodDaily-disposable MCLs (Fusion 1 day Presbyo) were fitted on both eyes of the subjects. For each lens fit a slit lamp digital picture and videokeratograph image were taken in a rapid but randomised sequence. Photo-editing software was used to assess the position of the MCL centre with respect to pupil centre as taken from the slit lamp photograph. The position of the MCL centre was automatically detected as the point of maximum curvature from the videokeratography. Three further manual and qualitative procedures to detect MCL centre, comparing a template of CLs optic zones to the videokeratographic image were performed by 4 practitioners using 3 different algorithms to represent the topographic map. Each manual reading was repeated 3 times. ResultsTwenty-two subjects (11 males) aged 22.8 ± 1.9 years (range 20.8–27.0 years) were recruited. The accuracy of the 4 topographic assessments in determining the centre coordinates of the MCL with respect to SL assessment was good: no differences were found in the left eyes and although in the right eyes a more temporal and superior position of MCLs was determined (paired t-test, p < 0.05) the difference was clinically negligible (0.16 ± 0.36 mm horizontally, 0.23 ± 0.48 vertically). Amongst the 4 practitioners one-way Anova for repeated measures showed no differences for any of the 3 manual assessments. Intra-class correlation coefficient was calculated among the 3 readings for each manual procedure and was very good (between 0.75 and 0.98) in 3 practitioners and moderate (between 0.49 and 0.92) in the fourth. ConclusionsThe assessment of MCL centration by performing corneal topography over the MCL is an accurate method. Furthermore, inter and intra-practitioner reliability showed by manual procedures appeared very good.

152 Multi-Center Experience Utilizing Collagen Fleece for Plaque Incision with Grafting to Correct Residual Curvature at Time of Inflatable Penile Prosthesis Placement in Peyronie's Disease Patients

Adjuvant maneuvers are often necessary to correct residual curvature during inflatable penile prosthesis (IPP) placement in Peyronie’s Disease (PD) patients. We present our multi-center experience using collagen fleece as graft material for plaque incision and grafting (PIG) during IPP placement in patients with moderate to severe PD. We retrospectively reviewed 50 IPP patients from 3 sites who underwent PIG with Tachosil® (Baxter, IL, USA) collagen fleece. Coloplast (Humlebaek, Denmark) IPP devices were used. Surgical technique has been previously described (Figure). Briefly, a subcoronal incision is made, and the neurovascular bundles are raised in standard fashion. A linear incision is created at the point of maximum curvature with device inflated at 70%. The device is maximally inflating demonstrating the defect. The collagen fleece is bathed in saline and then moulded overtop the defect with at least 5 mm of margin coverage. Buck’s fascia is re-approximated to support the underlying graft. Factors associated with residual curvature, revision and patient satisfaction was performed using chi-squared analysis.

Boundary layers in Helmholtz flows

Recent comparisons between classical Wagner theory for the impact of two liquid droplets and direct numerical simulations in Cimpeanu &amp; Moore (J. Fluid Mech., vol. 856, 2018, pp. 764–796) show that, in some regimes, the inviscid theory over-predicts the thickness of the root of the splash jet that forms in the impact, while also struggling to predict the angle at which the jet is emitted. The effect of capillary and viscous perturbations to Helmholtz flows was investigated in a previous study, see Moore et al. (J. Fluid Mech., vol. 742, 2014, R1). However, the paper in question ignored a term in the second-order perturbation analysis, which needs to be included in order to predict the displacement of the inviscid free boundary to lowest order. In this paper, we derive a singular integro-differential equation for the free-surface perturbations caused by viscosity in Helmholtz flows and discuss its application both in the context of Wagner theory and more generally. In particular, viscosity can induce non-monotonic behaviour in the free boundary profiles near points of maximum curvature.

Calculation of the aortic arch angles from three-dimensional reconstructions of computed tomography scans: Comparison between an automated program and visual assessment

BackgroundThe curvature of the aortic arch is associated with the risk of endoleak formation after thoracic endovascular aortic repair (TEVAR). However, the adequate assessment of the angles of the aorta continues to represent a major difficulty. We developed a new program based on three-dimensional (3D) reconstructions of computed tomography (CT) scans to objectively identify the location of the aortic points of maximum curvature, and to automatically calculate the main aortic arch angles, comparing final values with visual assessment methods. MethodsThis is a cross-sectional validation study of a convenience sample of subjects with multislice CT angiography scans of the thoracic aorta from an institutional imaging database. The center lumen line (CLL) of the aorta was determined semi-automatically using Endosize software. The points of maximum curvature on the CLL were determined by two methods: visually by two physicians and through a custom program. ResultsThe study enrolled 9 subjects: 4 with thoracic aneurysms and 5 with normal aortas. The inter-observer and inter-method correlation, agreement and reliability for each of the 3D spatial coordinates of the points of maximum curvature were appropriate. However, the aortic angles determined by visual assessment showed a very low to moderate correlation and reliability with those determined by our custom program. ConclusionAn automated custom program can reflect clinician's intuitive assessment of the location of points of maximum curvature and translate it into aortic angles with an apparently higher precision, reducing potential error and user time.

Long-Term Results after Surgical Treatment of Congenital Penile Curvature Using a Modified Nesbit Technique.

PurposeCongenital penile curvature (CPC) is a rare condition with surgical correction being the standard therapy. In the current study, we report long-term results analyzing the surgical and functional outcomes using a modified Nesbit technique.Materials and MethodsPatients with CPC were included. After penile degloving and mobilization of the neurovascular bundle an artificial erection was performed. An ellipsoid part of the tunica albuginea was excised at the point of maximum curvature on the convex side of deviation. The tunical defect was then closed by interrupted absorbable sutures with inverted knots. Results of correction were documented intra- and postoperatively by artificial erection. Pre- and postoperative evaluation included measurement of penile length and curvature after pharmacological erection. Erectile function, alteration in glans sensation, palpable suture as well as short- and long-term complication were also recorded using validated questionnaires and objective examinations.ResultsFifty-five patients with mean age 26.93 years (14–66 years) and mean curvature 69.81° (25°–90°) were included in the study. Ventral or ventrolateral curvature was observed in 83.6%. Mean operative time was 106.8 minutes (55–169 minutes). Totally straightness of the penis was achieved in 51/55 patients (92.8%). After a mean long-term follow-up of 36.68 months (4–87 months), erectile function worsened in 3.6% of patients. Median penile length loss associated with this technique was 1.7 cm (0–3.0 cm).ConclusionsSurgical therapy of CPC using our modified Nesbit technique is feasible, safe and provides reliable long-term outcomes, representing an alternative for surgical correction of CPC.

Micro-Computed Tomography (Micro-CT) Evaluation of Effects of Different Rotary Glide Path Techniques on Canal Transportation and Centering in Curved Root Canals.

BackgroundThe aim of this study was to evaluate the ability of different rotary glide path techniques to maintain canal anatomy by comparing canal transportation and centring abilities in curved root canals using X-ray micro-computed tomography (micro-CT).Material/MethodsWe selected 36 root canals and randomly assigned them to 3 groups. The first group was instrumented using Pathfile (PF) 1 and PF2, the second group using PF2, and the third group using a Proglider (PG) instrument. Selected tooth samples were scanned using a micro-CT system with 8-μm resolution. Centring ability and transportation were compared at 5 levels: 0.5 mm (A0) and 1 mm (A1) from apical foramen, at the point of maximum root curvature (C0), at 1 mm below it (C−), and 1 mm above it (C+). Area, ratio of areas (RA), perimeter, centroid shift, mean diameter, and ratio of diameter ratios (RDR) were assessed.ResultsIn all groups, there were no significant differences between different levels in all parameters (p>0.05). In group 1, the centroid shift was greatest at A0 and C−, and the least impact was at C0. In group 2, the biggest impacts were at C− and A0, and the smallest at C+. In group 3, the greatest impacts were at A0 and A1, and the smallest at C0.ConclusionsAll 3 instrument groups performed very similarly, without significant differences in canal-shaping parameters. Overall, using just PF2 instead of PF 1 and 2 created very similar shaping results, which could reduce the number of instruments needed and the cost of treatment.

3D geometric morphometric analysis of variation in the human lumbar spine.

The shape of the human lumbar spine is considered to be a consequence of erect posture. In addition, several other factors such as sexual dimorphism and variation in genetic backgrounds also influence lumbar vertebral morphology. Here we use 3D geometric morphometrics (GM) to analyze the 3D morphology of the lumbar spine in different human populations, exploring those potential causes of variation. We collected 390 (semi) landmarks from 3D models of the CT scans of lumbar spines of seven males and nine females from a Mediterranean population (Spain, Israel) and seven males and either females from a South African population for geometric morphometric (GM) analysis. We carried out Generalized Procrustes Analysis, Principal Components, and Regression analyses to evaluate shape variation; and complemented these analyses with the Cobb Method. The Mediterranean sample was considerably more lordotic than the South African sample. In both populations, female lumbar spines showed proportionally narrower and more craniocaudally elongated lumbar segments than in males. In addition, the point of maximum curvature in females tended to be located more inferiorly than in males. Our results show that sexual dimorphism is an important factor of lumbar spine variation that mainly affects features of lumbar spine robustness (height proportions) and the structure-but not the degree-of its curvature. Differences in lordosis, however, are clearer at the inter-population level. This reflects previous conflicting studies casting doubts on pregnancy as an adaptive factor influencing lordosis. Other factors, for example, shape of the individual lumbar vertebrae and intervertebral discs and their relative proportions within the lumbar spine should be considered when exploring variation in vertebral column morphology.

Inflatable penile prosthesis with plaque incision and grafting with TachoSil for Peyronie’s disease (PICS Technique)

Background: Residual curvature correction during inflatable penile prosthesis (IPP) implantation in patients with Peyronie’s disease (PD) is common. The PICS Technique, that is plaque incision and grafting with the self-adhesive TachoSil ® (Baxter, CA, USA), is a novel option to address residual curvature in these cases. In order to understand the surgical technique and improve surgical outcomes the urologist should follow a standardized approach. The aim of this study is to provide tips and tricks for the PICS Technique. Methods: The present study offers a step-by-step tutorial for the PICS Technique. The author describes his surgical technique in detail and provides important aspects and tips one has to be aware of when performing the PICS Technique. Surgical videos will highlight the most important steps during the approach. Indications to perform this technique will also be presented. Moreover, postoperative management strategies will be discussed. Results: The PICS Technique can be applied when residual curvature is >40° after insertion of the IPP. Important steps include penile degloving, opening of Buck’s fascia and mobilization of the neurovascular bundle. The device is then inflated, and plaque incision is performed at the point of maximum curvature. The defect of the tunica albuginea is then closed/sealed with the TachoSil ® , which does not require suture fixation. Finally, Buck’s fascia and the penile skin are closed. Postoperatively, the device is left inflated 40–50% for a period of 4 weeks. Sexual intercourse is possible 6 weeks following the surgical procedure. Close follow-up is recommended in order to detect possible complications/problems. Conclusions: The present study offers a step-by-step tutorial for the PICS technique, in order to help the reader to understand major steps during the procedure and to avoid pitfalls. The surgical videos help visualization of crucial surgical steps. A standardized approach and adequate postoperative management are main predictors for success and patient satisfaction.

Plaque incision at point of maximum curvature, with the device inflated

Plaque incision at point of maximum curvature, with the device inflated

Micro-CT evaluation of ProTaper Next and WaveOne Gold shaping in maxillary first molars curved canals: an in vitro study

Introduction: The aim of this micro-CT study was to analyze the geometrical shaping outcomes after instrumentation with rotary and reciprocating glide path and shaping systems. Materials and Methods: The mesio-buccal canals of thirty extracted maxillary first permanent molars were randomized into two groups (n=15): rotary system ProGlider and ProTaper Next X1, X2 (PG-PTN) was compared with reciprocating system WaveOne Gold Glider and WaveOne Gold Primary (WOGGWOG). Irrigation was performed with EDTA 10% and NaOCl 5%. Specimens were micro-CT scanned before instrumentation and after glide path and shaping. The measured parameters were the increase in canal volume and surface area, the centroid shift and the canal geometry variation through RDR and RA. These parameters were measured in the apical and coronal levels and at the point of maximum curvature. One-way ANOVA and post hoc Turkey- Kramer tests were used to describe the impact of the instrumentation on the selected parameters (P<0.05). Results: Post glide path analysis revealed that increase in canal surface area was slightly greater in WOGG group (P=0.051). Centroid shift was not significant even if the trend seemed more favorable to PG group, except for the apical third. Centroid shift reported no significant differences. Conclusions: Both rotary and reciprocating systems seemed to create a homogeneous and well-centered glide path and shaping.

Circle reproduction with interpolatory curves at local maximal curvature points

We present a piece-wise rational, quadratic, interpolatory curve that is able to reproduce circles and other elliptical or hyperbolic shapes. The curve is curvature continuous except at infection points and points of local maximum curvature appear only at control points and nowhere else. The local maximum curvature property ensures that users have direct control over salient points of the curve, and users can control if and where features such as cusps and loops are generated.To construct the desired curve, we formulated an energy that encodes the desired properties to optimize using a boxed constrained optimization. We provide an efficient algorithm for choosing an initial guess close to the solution to accelerate convergence. In addition, we show how to automatically choose the rational weights of the curve as part of the optimization to reproduce shapes such as circles.

A new biometric system based on inner-knuckle-print recognition

Biometrics is a highly efficient method of personal identification in civil fields. In this paper, we present a new biometrics system based on inner-knuckle-print (IKP). A new IKP image acquisition device with a finger guide is built for restricting the finger posture in a friendly way. A modified maximum curvature point method is proposed for feature extraction; it can extract the central region of the IKP line pattern robustly against illumination variation. The experimental results show that the proposed method achieves the equal error rate of 0.36%, performing better other traditional methods. In addition, it works in real-time.

Pore structure and permeability of filter cake in coal slurry filtration

ABSTRACT The dewatering performance is dependent on the understanding of the pore structure and permeability of the filter cake in coal slurry filtration. In this paper, filter cakes were prepared from three different coal samples under the filtration pressure of 0.6 MPa with different filtration times, and the pore distribution and pore complexity of filter cakes were investigated using image processing technology and fractal theory, and the calculation of permeability of filter cakes were carried out on the basis of Darcy’s law. With an increase in filtration time, the filter cake is characterized by smaller pore diameter and porosity, narrower pore diameter distribution, and greater fractal dimension. The relationship between the permeability of filter cake and its thickness in filtration process obeys first-order exponential decay, and it could be expressed by . The critical thickness of filter cake is proposed and calculated using the maximum curvature point of K(Lc) curve, which provides theoretical support for achieving high-efficiency filtration of coal slurry.

Machine Learning Prediction of Tissue Strength and Local Rupture Risk in Ascending Thoracic Aortic Aneurysms

A Multi-layer Perceptron (MLP) neural network model [1] is developed to predict the strength of ascending thoracic aortic aneurysm (ATAA) tissues using tension-strain data and assess local rupture risk. The data were collected through in vitro inflation tests on ATAA samples from 12 patients who underwent surgical intervention [2]. An inverse stress analysis was performed to compute the wall tension at Gauss points. Some of these Gauss points are at or near sites where the samples eventually ruptured, while others are at locations where the tissue remained intact. A total of 27,648 tension- strain curves, including 26,676 2223 nonrupture and 972 rupture were garnered and each fitted to a third order NURBS function with 3 knot intervals. A typical fitted curve is shown in Fig. 1, which has a J-shape with a compliant elastin-dominated region at the low strain range, a transition phase in the middle, and a stiff collagen-dominated region at the high strain end. Eight features associated with the low strain region response are extracted: the tension, strain, slope and curvature at the maximum curvature point and a transition point (Figure 1). These features are subsequently fed to the machine learning model. <br/> As a first step, the model is trained using data in the rupture group. A 12-fold cross-validation method is employed. Specifically, among all 12 samples, the model is repeatedly trained using data from 11 samples and tested on the one left. Fig. 2 shows the predicted rupture tension vs actual rupture tension. As we can see from the figure, the strength is well predicted. The average mean absolute error (AMAE) and average cross-validation R² score are 0.096 and 0.954, respectively. <br/> The results above confirm the feasibility of predicting the ATAA tissue strength using pre-rupture responses features extracted from the tension-strain curves. To further validate the model, we use the same protocol to train the model; however, the trained model is applied to all curves in both rupture and nonrupture groups in each sample. Fig. 3(a) shows the predicted strength versus the end tension in all curves. The results are evaluated from two perspectives. First, within the non-rupture group, we consider a strength prediction greater than the end tension as a positive prediction (PP), otherwise a negative prediction (NP), The positive predictions account for around 86 % for all samples (Fig. 3(b)), indicating that the model is reasonably trustworthy in terms of PP output. Secondly, a local rupture risk factor, which is the ratio of the end tension to the predicted rupture tension, is defined. The risk factor distribution and the actual rupture image for each sample are compared and presented in Fig. 4 (only 10 samples showed due to the page limit). A purple square is used to mark the ‘hot spot’ (regions of peak risk factor) and the location of the onset of rupture. samples). These two spots match generally well in 10 samples (including two unshown samples). For sample 6 (the first one on rows 3 and 4), there are two ‘hot spots’ and one matches with the rupture location. For sample 2, the hot spot does not closely match the rupture site. However, this sample bears a V-shape crack in the proximity of the boundary. It is unclear where exactly the crack initiates, and also, it is possible that rupture is caused by fixture. In sum, these examinations further validate the model and demonstrate the promise of predicting local rupture propensity.

Shaping Ability of ProTaper Universal, ProTaper NEXT and WaveOne Primary in Severely Curved Resin Blocks

Complex anatomy of roots requires endodontic rotary instruments that respect and follow that anatomy. The purpose of this study was to compare the shaping ability of three engine-driven nickel-titanium instruments in severely curved simulated canals. Forty-eight severely curved simulated canals in resin blocks were prepared to an apical size of 25 using the following systems (n = 16 per group): ProTaper Universal (PTU), ProTaper NEXT (PTN), and WaveOne Primary (WO) (all Dentsply Maillefer, Ballaigues, Switzerland). Composite images were made from the superimposition of pre- and post-instrumentation images. The amount of resin removed by each system was measured by using a digital template and image analysis software. Shaping ability of each system was compared using different parameters: total resin removal, centering ability, canal transportation in the apical, middle and coronal third of canal. Preparation times were also recorded. The data were statistically analyzed by using analysis of variance, paired t-test, and Tukey's post hoc test. Canals prepared with PTN were better centered in the apical part than those prepared with WO and PTU (p < 0.05). WO removed significantly more resin at the outer aspect of the maximum point of curvature. WO and PTU caused similar canal transportations at 7 points out of 11 measuring points. At measuring points 3, 4, and 5 WO caused more canal straightening than PTU. Instrumentation with PTU required more time than with the two other instruments (p <0.05). No preparation error or instrument separation occurred. In the apical part of the canals PTN obtained the best results with regard to canal transportation. All of the rotary instruments were safe in preparing severely curved canals and PTN showed better preparation of apical part of the canal.

Time-Optimal Trajectory Planning along Parametric Polynomial Lane-Change Curves with Bounded Velocity and Acceleration: Simulations for a Unicycle Based on Numerical Integration

G2 lane-change path imposes symmetric conditions on the path geometric properties. This paper presents the comparative study of time-optimal velocities to minimize the time needed for traversal of three planar symmetric parametric polynomial lane-change paths followed by an autonomous vehicle, assuming that the neighboring lane is free. A simulated model based on unicycle that accounts for the acceleration and velocity bounds and is particularly simple for generating the time-optimal path parameterization of each lane-change path is adopted. We base the time-optimal trajectory simulations on numerical integration on a path basis under two different end conditions representing sufficient and restricted steering spaces with remarkable difference in allowable maximum curvature. The rest-to-rest lane-change maneuvering simulations highlight the effect of the most relevant path geometric properties on minimal travel time: a faster lane-change curve such as a quintic Bezier curve followed by a unicycle tends to be shorter in route length and lower in maximum curvature to have achievable highest speed at the maximum curvature points. The results have implications to path selection for parallel parking and allow the design of continuous acceleration profile via time scaling for smooth, faster motion along a given path. This could provide a reference for on-road lane-change trajectory planning along a given path other than parametric polynomials for significantly more complex, complete higher-dimensional highly nonlinear dynamic model of autonomous ground vehicle considering aerodynamic forces, tire and friction forces of tire-ground interaction, and terrain topology in real-world.

Introducing the ventral sealing technique using collagen fleece for surgical therapy of patients with ventral Peyronie's curvature: initial experience.

Ventral penile curvature in Peyronie's disease (PD) is not very common but may lead to inability for sexual intercourse, especially in severe cases > 60°. Ventral curvatures are most often addressed surgically with plication owing to fear of urethral complications, as it requires the mobilisation of the urethra. In this study, the ventral sealing technique is introduced for correction of ventral curvatures in patients with PD. The surgical approach includes the mobilisation of the neurovascular bundle and the urethra. At the point of maximum curvature on the ventral aspect of the penis, a partial plaque excision is performed and the resulting tunical defect is sealed (closed) with a self-adhesive collagen fleece (TachoSil®, Baxter, IL, USA) that does not require suture fixation. Twelve patients with severe ventral curvature were included in this study. Mean penile curvature was 98.3° (sd ± 27.6, range: 60-150). Mean operative time was 99.2 minutes (sd ± 12.4, range: 80-130). Mean follow-up was 17.9 months (sd ± 8.0, range: 9-29). Ten out of 12 patients (83.3%) showed a totally straight penis. Two patients (16.7%) had a residual curvature of < 30°, which did not interfere with sexual intercourse. All patients were able to perform satisfying sexual intercourse. Initial results of the ventral sealing technique are encouraging. However, long-term data are necessary.

Impact of a Displaced Corneal Apex in Small Incision Lenticule Extraction.

To evaluate the possible impact of a displaced corneal apex (point of maximum curvature) on visual results and tomographic parameters after small incision lenticule extraction (SMILE). In this retrospective evaluation, eyes with uncomplicated SMILE for myopia correction were classified in two groups based on their preoperative distance between the corneal apex and corneal vertex (corneal intercept with the patient's line of sight) of 1 mm or greater (large A-V distance) or less than 1 mm (small A-V distance). All surgeries were performed during the early learning curve of two surgeons. Visual outcome parameters included uncorrected (UDVA) and corrected (CDVA) distance visual acuity, manifest refractive spherical equivalent (MRSE), and refractive astigmatism 3 months postoperatively. Scheimpflug-derived tomographic outcome parameters included mean keratometry value, root mean square higher order aberrations (RMS HOAs), and optical zone decentration. The study comprised 94 eyes of 48 patients: 44 eyes in the large A-V distance group and 50 eyes in the small A-V distance group. Preoperative and postoperative RMS HOAs were significantly higher in the large A-V distance group than in the small A-V distance group (P = .002 and .008, respectively). Postoperative CDVA was significantly better in the small A-V distance group (P = .014). There were no statistically significant differences in postoperative UDVA, MRSE, refractive astigmatism, mean keratometry value, and optical zone decentration. After SMILE, CDVA was significantly worse in eyes with a preoperatively displaced corneal apex compared to eyes with a more central corneal apex. However, good visual results were achieved in both groups. [J Refract Surg. 2018;34(7):460-465.].