Average Disc Research Articles

Neuro-ophthalmological biomarkers of visual outcome in newly diagnosed idiopathic intracranial hypertension

BackgroundIdiopathic intracranial hypertension (IIH) is a disorder of unidentified etiology characterized by raised intracranial pressure (ICP) without clinical, laboratory, or radiological evidence of intracranial pathology. The aim of this work was to determine the visual outcome in newly diagnosed IIH patients.MethodsThe study included 68 IIH patients; 59 responded to medical treatment and nine needed lumboperitoneal shunting (LPS). Patients were submitted to papilledema grading using Frisén Scale, water CSF manometry, brain MRI/MRV, mean deviation of visual field examination (MD-VFE), optic nerve sheath diameter (ONSD), average optic disc optical coherence tomography–retinal nerve fiber layer (OCT–RNFL) thickness, and pattern–reversal visual evoked potential (VEP).ResultsPatients needed LPS showed statistically significant increase in baseline papilledema grade, MD-VFE, ONSD, average OCT–RNFL thickness, and P100 VEP latency. On the other hand, both studied groups showed statistically non-significant differences regarding the patients’ ages and opening CSF pressure.ConclusionNewly diagnosed IIH patients’ evaluation must be based on multimodality neuro-ophthalmological assessment where papilledema grade, MD-VFE, and OCT–RNFL are valuable biomarkers of PVD while P100 VEP latency delay is a predictor of poor visual outcome and ONSD is an early indicator of elevated ICP regression after LPS surgery.

The Individual Thicknesses of Stellar Disks of Galaxies Viewed at Arbitrary Angles

A method for determining the thickness of the stellar disk of a galaxy from a photometric image of the galaxy in the plane of the sky is proposed and justified. The method can be applied to determine the thickness of plane-parallel exponential disks with an arbitrary, radius-independent, luminosity distribution perpendicular to the plane of the disk J(r, z) = exp(-r/h)f(z). A special feature and advantage of the method is that it enables determination of the thicknesses of disks viewed at arbitrary angles to the plane of the sky (but not strictly edge-on or face-on). The key idea of the method is finding the true inclinations of galaxies viewed at arbitrary angles not from their isophotes, but instead from the azimuthal distribution of the exponential parameter h. The difference between the inclination determined in the traditional way using the isophotes and the true inclination enables estimation of the thickness of the disk. The effectiveness of the method for determining the inclinations of plane-parallel disks is confirmed using a sample of model isothermal galactic disks: I(r, z) = I0 exp(-r/h)sech2(z/z0). The inclinations of the planes of the model galaxies to the line of sight and the relative thicknesses in the model sample vary arbitrarily, making it possible to determine the limits of applicability of the method: z0/h < 0.7 and 10° <i < 75°.A sample of 44 piecewise-exponential disks of galaxies of the southern sky clusters is used to illustrate the application of the technique to observational data. Comparing the distribution of inclinations calculated using the new method and the traditional isophote method shows that the new method yields a more uniform distribution of inclinations to the plane of the sky for the sample galaxies. The derived average disk thicknesses and the disk-thickness distributions are consistent with statistical estimates and observational data from the literature for samples of galaxies viewed edge-on

Robust optic disc and cup segmentation with deep learning for glaucoma detection

Glaucoma is rated as the leading cause of irreversible vision loss worldwide. Early detection of glaucoma is important for providing timely treatment and minimizing the vision loss. In this paper, we developed a robust segmentation method for optic disc and cup segmentation using a modified U-Net architecture, which combines the widely adopted pre-trained ResNet-34 model as encoding layers with classical U-Net decoding layers. The model was trained on the newly available RIGA dataset, and achieved an average dice value of 97.31% for disc segmentation and 87.61% for cup segmentation, comparable to that of the experts’ performance for optic disc/cup segmentation and Cup-Disc-Ratio (CDR) calculation on a reserved RIGA dataset. When tested on DRISHTI-GS and RIM-ONE dataset without re-training or fine-tuning, the model achieved comparable performance to that of the state-of-the-art in literature. We have also fine-tuned the model on two databases, which achieves an average disc dice value of 97.38% and cup dice value of 88.77% for DRISHTI-GS test set, disc dice of 96.10% and cup dice of 84.45% for RIM-ONE database, which is the state-of-the-art performance on both databases in terms of cup dice and disc dice value. The advantage of the proposed method is the combination of the pre-trained ResNet and U-Net, which avoids training the network from scratch, thereby enabling fast network training with less epochs, thus further avoids over-fitting and achieves robust performance.

Disc Configuration as a Risk and Prognostic Factor in NAION: The Impact of Cup to Disc Ratio, Disc Diameter, and Crowding Index

ABSTRACTPurpose: The presence of the so called disc at risk (a small disc with no cupping) has been considered the main risk factor for the development of non-arteritic anterior ischemic optic neuropathy (NAION). However its role as a prognostic factor has not been studied. Our aim was to determine the weight of disc configuration as a risk and a prognostic factor for NAION.Methods: Case control study. Forty eyes of 40 patients who were diagnosed with NAION between 2008 and 2017, and 120 controls (3 controls for each patient) were included in the study. Disc diameter (DD), cup to disc ratio (CDR), and peripapillar retinal nerve fiber layer thickness (RNFLT) of the non-affected eye were measured using optic coherence tomography (3D OCT 2000, Topcon). Crowding index (CI) was defined as the quotient of average RNFLT and disc area. Mean deviation (MD) at the time of diagnosis and at least three months later was determined using a Humphrey Visual Field Analyzer (SITA standard 24-2 strategy). Visual acuity (VA) was measured using Snellen charts and transformed into LogMAR values.Results: Only CDR was found to be a risk factor for NAION. No correlationship was found between CI and visual loss.Conclusions: DD and CI did not show value as either prognostic or risk factors. Glial tissue may be a part of the content of the optic disc as important as axons. Our results are in line with the latest studies about NAION pathophysiology. Contrary to classic thinking, these papers have not found smaller disc diameters, but smaller values of lamina cribosa depth in NAION patients.

Morphometric Analysis of Lumbar Intervertebral Disc Height: An Imaging Study

Little published data exist regarding normal values of disc height. Current literature relies on plain radiographs making accurate measurements of individual lumbar disc height difficult. We seek to establish normal values for lumbar intervertebral discs in different age groups using computed tomography scans in healthy individuals. Two hundred forty anonymized abdominal computed tomography scans (131 women) were prospectively collected once institutional review board approval was obtained. Individuals with spinal pathologies were excluded. Disc height measurements were obtained at the anterior edge, center, and posterior edge of each vertebra in the midsagittal plane, averaged, and compared against age and sex. Average age was 45 (14-83) years for women and 48 (14-89) years for men. Average lumbar disc height was 5.6 ± 1.1 mm for men and 4.8 ± 0.8 mm for women at T12/L1, 6.9 ± 1.3 mm for men and 5.8 ± 0.9 mm for women at L1/2, 8.1 ± 1.4 mm for men and 6.9 ± 1.1 mm for women at L2/3, 8.7 ± 1.5 mm for men and 7.6 ± 1.2 mm for women at L3/4, 9.2 ± 1.6 mm for men and 8.5 ± 1.6 mm for women at L4/5, and 8.8 ± 1.6 mm for men and 8.6 ± 1.8 mm for women at L5/S1. Disc height was significantly smaller for women than men (P < 0.001), except at L5/S1. Variation in disc height is determined much more by sex than age. The maximum height of the interbody space in the adult lumbar spine was at the L4/5 level (8.9 ± 1.7 mm [men], 8.6 ± 1.8 mm [women]). Basedonour findings, >10 mm cage height will result in supraphysiologic interbody space restoration and potentially predispose to complications.

What every spine surgeon should know about transforaminal lumbar interbody fusion surgery for herniated discs.

The aim of this study is to report our experiences on managing large lumbar disc herniations with several symptoms by surgery with transforaminal lumbar interbody fusion (TLIF) and to shed light for spine surgeons about TLIF surgery. We retrospectively evaluated our database of patients with various lumbar spine pathologies who underwent TLIF surgery from 2014 to 2017. We separated 18 patients who had been operated on for extruded disc herniation, which causes severe pain and radicular symptoms. The pain was quantified by visual analog scores (VAS). The disability status were pre-operatively and post-operatively evaluated by the Oswestry Disability Index (ODI). We evaluated the patients for at least two years. Interbody fusion was detected by routine radiographs at six, 12, and 24months after surgery. An ODI outcomes analysis demonstrated a statistically significant improvement in the six and 24-month mean scores compared with the pre-operative scores on the same scales. Patients' mobility improved significantly after surgery, as indicated by the decrease in the Oswestry Disability Index from 72 to 23 over twoyears (p < 0.001). Pain rapidly decreased in all patients and continued to decrease at the time of the latest follow-up. The mean pre-operative VAS scores for pain was 8.8; it had improved to 2.4 after surgery (p < 0.05). Within the follow-up period of twoyears, the ascertained mean VAS declined from 8.8 to 1.4 (p < 0.001). The average disc space height at the herniated levels was fairly well maintained. No patient had evidence of implant failure. Interbody fusion was graded as definitely solid in 100% of cases twoyears post-operatively. One patient displayed a superficial wound infection. Following appropriate debridement and antibiotics, the wound healed without sequelae. No major complications were observed, including permanent neurological deficit, pulmonary embolism, peri-operative cardiac event, or death. The findings of our study and those in the literature showed that primary herniated disc patients with radicular and chronic low back pain, degenerative changes, bi-radicular symptoms, and instability are required to have fusion after a discectomy. Being a heavy-duty worker is also a criterion for fusion surgery. TLIF is performed by a unilateral approach preserving the interlaminar surface on the contralateral side, which can be used as a site for additional fusion. As an effective results TLIF procedure should be chosen for fusion surgery.

Hypermassive Neutron Star Disk Outflows and Blue Kilonovae

Abstract We study mass ejection from accretion disks around newly formed hypermassive neutron stars (HMNSs). Standard kilonova model fits to GW170817 require at least a lanthanide-poor (“blue”) and lanthanide-rich (“red”) component. The existence of a blue component has been used as evidence for an HMNS remnant of finite lifetime, but average disk outflow velocities from existing long-term HMNS simulations fall short of the inferred value (∼0.25c) by a factor of ∼2. Here we use time-dependent, axisymmetric hydrodynamic simulations of HMNS disks to explore the limits of the model and its ability to account for observations. For physically plausible parameter choices compatible with GW170817, we find that hydrodynamic models that use shear viscosity to transport angular momentum cannot eject matter with mass-averaged velocities larger than ∼0.15c. While outflow velocities in our simulations can exceed the asymptotic value for a steady-state neutrino-driven wind, the increase in the average velocity due to viscosity is not sufficient. Therefore, viscous HMNS disk winds cannot reproduce by themselves the ejecta properties inferred from multi-component fits to kilonova light curves from GW170817. Three possible resolutions remain feasible within standard merger ejecta channels: more sophisticated radiative transfer models that allow for photon reprocessing between ejecta components, inclusion of magnetic stresses, or enhancement of the dynamical ejecta. We provide fits to our disk outflow models once they reach homologous expansion.

An Improved Dynamic Fault Tolerant Management Algorithm during VM migration in Cloud Data Center

Abstract Virtualization technology is widely accomplished in the data centers of the Cloud, for computing resources. The computation of the data for corresponding users creates via a group of connected Virtual Machines (VM) in an accessible and flexible manner. It improves the utilization of resources and thus it minimizes the usage of more hardware. The VM based infrastructure overhaul schemes are necessary to repossess affected services in an appropriate manner. Dedicated routing clarifications are also desirable for the improvement of providing reliability of Virtual DC (Domain Controller) services. In the occasion of node failure, the corresponding virtual machine face the challenges in determining which and how many VMs should be selected for migration to maintain reliability. The selection of VM plays an important part in limiting the number of VM migrations. The problem consists of selecting one or more potential VMs for migration to reduce the resource load of the considered servers. We propose a new Dynamic Fault Tolerant VM Migration (DFTM) for the enforcement of cloud data center infrastructure reliability through advanced recovery mechanism of VN (Virtual Network) demands. Integer Linear Programming model is implemented for analyzing the route traffic which considers all related numerical factors to choose optimal VM via the optimal path. Then, Alternative Switch Identification Algorithm determines the new VM migration and routing is accomplished. We used Cloudsim to implement and measure the effectiveness of the proposed DFTM algorithm. Then, we compared our results with existing methodologies in terms of overall execution time, average resource usage time, disk usage, and other performance metrics. Experimental results illustrate that the proposed fault recovery algorithm enhances the survivability of the VM based cloud data center.

Anterior Transcorporeal Approach to Percutaneous Endoscopic Cervical Diskectomy for Single-Level Cervical Intervertebral Disk Herniation: Case Series with 2-Year Follow-Up

To examine the effects of anterior transcorporeal percutaneous endoscopic cervical diskectomy (ATPECD) for the treatment of single-level cervical intervertebral disk herniation (CIDH) with a focus on its safety, feasibility, clinical efficacy, and specific possible complications. A series of 35 patients with symptomatic single-level CIDH were enrolled to be treated with ATPECD. Neck and arm pain was measured using the visual analog scale. Quality of life was measured using the bodily pain and physical function on the SF-36. The average disk height and vertical vertebral body height were recorded. Bone healing was evaluated on the basis of postoperative computed tomography. Successful removal of the herniated disk was confirmed in all 35 cases. At 2 years, the patients showed a significant treatment effect in the visual analog scale and body pain and physical function portions of the SF-36 (1.14 ± 0.60 vs. 7.62 ± 0.61, 63.92 ± 6.74 vs. 32.55 ± 6.80, and 82.14 ± 6.22 vs. 34.43 ± 4.50, respectively, P < 0.01). Mean preoperative disk height was 6.79 ± 0.37 mm, which decreased to 6.34 ± 0.46 mm 2 years post operation (6.6% decrease). Preoperative surgical vertebral body height also decreased from preoperation (15.79 ± 0.52 mm) to 2 years post operation (15.12 ± 0.38 mm) (4.2% decrease). Three surgery-related complications were observed (8.6%). Preliminary clinical experience with ATPECD shows that it is safe, effective, feasible, and minimally invasive. Although it has some disadvantages, such as the need for repeated fluoroscopy, some minor complications, and nonsymptomatic disk height decreases, ATPECD can supplement minimally invasive surgeries in selected cases of CIDH.

How the height and the area of the annulus fibrosus affect the range of motion behavior: A stochastic analysis

The annulus fibrosus has substantial variations in its geometrical properties (among individuals and between levels), and plays an important role in the biomechanics of the spine. Few works have studied the influence of the geometrical properties including annulus area, anterior / posterior disc height, and over the range of motion, but in general these properties have not been reported in the finite element models. This paper presents a probabilistic finite element analyses (Abaqus 6.14.2) intended to assess the effects of the average disc height ( hp) and the area ( A) of the annulus fibrosus on the biomechanics of the lumbar spine. The annulus model was loaded under flexion, extension, lateral bending, and axial rotation and analyzed for different combinations of hpand A in order to obtain their effects over the range of motion. A set of 50 combinations of hp(mean = 18.1 mm, SD = 3.5 mm) and A (mean = 49.8%, SD = 4.6%) were determined randomly according to a normal distribution. A Yeoh energy function was used for the matrix and an exponential function for the fibers. The range of motion was more sensitive to hpthan to A. With regard to the range of motion the segment was more sensitive in the following order: flexion, axial rotation, extension, and lateral bending. An increase of the hpproduces an increase of the range of motion, but this decreases when A increases. Comparing the range of motion with the experimental data, on average, 56.0% and 73.0% of the total of data were within the experimental range for the L4–L5 and L5–S1 segments, respectively. Further, an analytic equation was derived to obtain the range of motion as a function of the hpand A. This equation can be used to calibrate a finite element model of the spine segment, and also to understand the influence of each geometrical parameter on the range of motion.

Application of let‐through energy to back‐up over‐current protection on high‐voltage feeders

Let-through energy (LTE) refers to the I 2 t or Joule energy that a conductor is exposed to during a fault on the feeder. This energy is influenced by the magnitude of the fault current and time it takes for the protection system to clear the fault. If the LTE exceeds the conductor thermal energy limit, the conductor will get damaged. This concept of LTE evaluation is applied to the inverse definite minimum time (IDMT) current based back-up protection elements on a multisource high-voltage feeder in a hypothetical and actual network. Another method to calculate the relay operating time for IDMT relays was developed based on an average disk speed of electromechanical over-current relay and the proportionality of its speed to the magnitude of the fault current. This method was incorporated into a software application to generate results. These results allow the user to evaluate the conductor LTE exposure, total fault time exposure, the effect of instantaneous fault clearing and the application of auto-reclose cycles. An energy-area evaluation was applied to quantify and evaluate small protection settings changes. The conclusion is that LTE analysis on back-up protection should be considered for high-voltage feeders to ensure that the conductors are protected.

The effect of standing vs. variants of the seated position on lumbar intersegmental angulation and spacing: a radiographic study of 20 asymptomatic subjects.

Pain while sitting is the primary complaint of many patients with lumbar spinal ailments, including those with discogenic low back pain and lumbar disc herniations. There has been little basic research on the different mechanical stresses that different sitting positions place on the spine. To demonstrate the effect of different sitting positions on lumbar intersegmental relationships. Twenty healthy male volunteer subjects were recruited. Lateral X-rays of the lower lumbar spine were taken in four positions: (I) relaxed lateral standing; (II) "standard" sitting position; (III) sitting on a "kneeling" chair; and (IV) unsupported sitting on a stool. Anterior and posterior disc height, disc space angulation, L1-S1 angulation and interspinous distance were measured. The L1-S1 lordotic angle in the standing position (48.8°±14.7°) was found to be statistically significantly greater than the angle measured with any of the sitting positions: the kneeling chair (34.0°±17.7°); hard-back chair (28.6°±14.3°); and the stool (16.6°±15.6°). Total average disc height (arithmetic sum of average disc heights L2-S1) in the lumbar spine varied with position: standing (40.5±7.75 mm); hard-back chair (38.5±6.9 mm); kneeling chair (38.4±7.9 mm); stool (36.9±7.1 mm). The mean interspinous distance over all the lumbar levels was significantly greater in each of the three seated positions than in the standing position: standing 6.8±4.5 mm; 11.6°±7.5° for the kneeling chair; 12.9±5.8 mm for the hard-back chair; 16.9±7.0 mm for the stool. If segmental flexion and segmental loading are the important biomechanical correlates of pain on sitting, such patients should be most comfortable in a kneeling chair, which most closely approximates the standing position. These basic findings will allow better assessment of different seating positions from an ergonomic perspective, and hopefully lead to improvements in chair design.

A novel in vivo porcine model of intervertebral disc degeneration induced by cryoinjury.

Degenerative disc disease involves sequential events that lead to the loss of cells, a decrease in disc matrix production, disc dehydration, and alteration of its biomechanical properties. The aim of this study was to determine whether cryoinjury of the nucleus pulposus performed through endplate perforation contributes to disc degeneration and to compare this technique with standard methods. Under general anesthesia, the lumbar discs of six pigs were exposed and randomly submitted to needle puncture of the annulus fibrosus (NeP), isolated endplate injury (EP), or cryoinjury using a 2.5-J Thompson cryoprobe applied through a single endplate perforation (EP+cryo). The remaining discs served as controls. Animals were sacrificed at two months and the harvested lumbar spines were submitted to CT scan and MRI investigations. Histologic analysis was performed to assess the degree of disc degeneration. CT scan showed that decrease in average disc height was more important after cryoinjury (49.3%) than after endplate perforation (16.9%) (P < 0.0001) or needle puncture (19.4%) (P < 0.0001). On MRI, the dehydration ratio was significantly more important after EP+cryo (60%) than after NP (40%) or EP (30%) (P < 0.0001). After cryoinjury, the histologic score developed for this study was significantly higher than after needle puncture or endplate perforation (P < 0.0001). Imaging and histological analysis showed that disc cryoinjury applied through endplate perforation was superior to the classical NeP and EP models to induce experimental disc degeneration. This model appears suitable for testing safety and efficacy of novel treatments of intervertebral disc degeneration.

Discards of elasmobranchs in a trammel net fishery targeting cuttlefish, Sepia officinalis Linnaeus, 1758, along the coast of Sicily (central Mediterranean Sea)

Several species of elasmobranchs are commonly found as bycatch or discard in both artisanal and industrial fisheries. In particular, in the Mediterranean Sea, only few studies are available about bycatch and discards of elasmobranchs in artisanal coastal fisheries. In this study, we focus our attention on elasmobranch catches in a trammel net fishery targeting cuttlefish (Sepia officinalis) in the southeastern Ionian coast of Sicily (central Mediterranean Sea). In 2017, during the peak S. officinalis fishing season (February–May), four species of the infraclass Batoidea (Raja radula, Dasyatis pastinaca, Torpedo marmorata and Torpedo torpedo) constituted the total elasmobranch catches of the 16 survey days. Catch per unit effort (CPUE) of T. torpedo, in both number of specimens and biomass terms, showed the highest value, accounting for about 50% of the total. Except for the three larger specimens of R. radula (1.7% of R. radula specimens caught), all elasmobranchs were discarded. An ANOVA showed significant differences (P<0.05) between monthly CPUE values of the four species; while, for each species, the chi-square test failed (P>0.05) to show a significant difference in monthly CPUE values. Average disc width of the specimens caught showed the overall presence of a large number of juveniles. Chi-square test for sex ratio showed a significant difference (P<0.05) only for T. torpedo. For D. pastinaca, survival rate was equal to 0. Local traditions play an essential role in fishermen’s choice to discard or retain fishes. Monitoring the impact of fishing on populations of these vulnerable or potentially vulnerable species is of fundamental importance for the development of management strategies.

Degenerative changes of the thoracic spine do exist in patients with diffuse idiopathic skeletal hyperostosis: a detailed thoracic spine CT analysis.

Background Degenerative intervertebral disease (DID) is an exclusion criterion in the Resnick and Niwayama radiographic classification for diffuse idiopathic skeletal hyperostosis (DISH). However, although DID was previously described in DISH, no systematic computed tomography (CT) analysis has been reported so far. Purpose To assess for the presence and prevalence of such changes on CT examinations of the thoracic spine of individuals with DISH. Material and Methods Intervertebral space (D1-L1) on chest CT examinations of DISH patients was retrospectively evaluated for the presence of DID. Parameters evaluated were disc space height, disc protrusion, subchondral cysts/sclerosis, Schmorl nodes, vacuum phenomenon, and posterior elements including costovertebral and facet joints. Parameters were compared with two age- and gender-matched control groups of individuals whose entire spine CT lacked evidence of DISH (Control 1 individuals < 2 flowing osteophytes, Control 2 individuals < 4 and ≥ 2 flowing osteophytes). Results A total of 158 participants (DISH/Control 1/Control 2 = 54/54/50; 106 men, 52 women; average age = 70.6 years) were evaluated. Average intervertebral disc height was significantly lower in the DISH group compared with both control groups (DISH/Control 1/Control 2 = 4.55/5.13/5.01 mm, P < 0.001). Costovertebral degenerative changes were more prevalent in DISH patients ( P < 0.05) and, except for vacuum phenomenon (more prevalent in controls), other DID changes were as prevalent in DISH as in controls. Conclusion The presence of degenerative intervertebral changes on thoracic CT should not deter from diagnosing DISH. Thus, the radiographic Resnick and Niwayama DISH criteria cannot be directly adapted to CT.

Effect of an Adjustable Hinged Operating Table on Lumbar Lordosis During Lumbar Surgery.

Prospective observational study. Quantify the amount of lumbar lordosis achieved on a hinged operative table in neutral, flexion, and extension. Hinged operative tables may allow surgeons to adjust lumbar spine positioning intraoperatively. The amount of lumbar lordosis in neutral, flexion, and extension positions has not been quantified prospectively using a hinged table. Thirty patients undergoing elective lumbar surgery were enrolled. Standing x-rays taken in neutral, maximal flexion, and maximal extension were obtained. After prone positioning on a hinged operative table, x-rays in neutral, maximal flexion, and maximal extension were taken. Total lumbar lordosis was calculated for all six images by two physicians. Disc degeneration was graded using Pfirrmann grades. Lumbar lordosis on the operative table was 56.5 ± 2.1, 43.6 ± 2.2, 63.2 ± 2.0 compared with 46.9 ± 3.1, 33.2 ± 2.8, 52.3 ± 3.3 on the standing films in neutral, flexion, and extension, respectively. Average flexion (12.9 ± 1.1) and extension (6.7 ± 1.2) were significantly different from neutral on the table (P < 0.001). Lumbar lordosis was significantly higher on the operative table (P < 0.001). Total range of motion was 19.6 ± 1.9 on the table and 19.1 ± 2.0 with standing (P = 0.42). Average Pfirrmann disc grade was 2.77 ± 0.10 that did not correlate with range of motion (P = 0.40). In this cohort, the hinged operative table allowed for a physiologic arc of motion of nearly 20 from flexion to extension. A considerable amount of lumbar sagittal motion can be obtained on hinged operative tables without decreasing overall lumbar lordosis below physiologic levels. 3.

Retinal Nerve Fiber Layer Protrusion Associated with Tilted Optic Discs.

This study resulted in the identification of an optic nerve head (ONH) feature associated with tilted optic discs, which might potentially contribute to ONH pathologies. Knowledge of such findings will enhance clinical insights and drive future opportunities to understand disease processes related to tilted optic discs. The aim of this study was to identify novel retinal nerve fiber layer (RNFL) anomalies by evaluating tilted optic discs using optical coherence tomography. An observed retinal nerve fiber protrusion was further investigated for association with other morphological or functional parameters. A retrospective review of 400 randomly selected adult patients with ONH examinations was conducted in a referral-only, diagnostic imaging center. After excluding other ONH pathologies, 215 patients were enrolled and evaluated for optic disc tilt and/or torsion. Gross anatomical ONH features, including size and rim or parapapillary region elevation, were assessed with stereoscopic fundus photography. Optical coherence tomography provided detailed morphological information of individual retinal layers. Statistical analysis was applied to identify significant changes between individual patient cohorts. A dome-shaped hyperreflective RNFL bulge, protruding into the neurosensory retina at the optic disc margins, was identified in 17 eyes with tilted optic discs. Available follow-up data were inconclusive regarding natural changes with this ONH feature. This RNFL herniation was significantly correlated with smaller than average optic disc size (P = .005), congenital disc tilt (P < .0001), and areas of rim or parapapillary elevation (P < .0001). This study reports an RNFL protrusion associated with tilted optic discs, which has not previously been assessed as an independent ONH structure. The feature is predominantly related to congenital crowded, small optic discs and variable between patients. This study is an important first step to elucidate diagnostic capabilities of tilted disc morphological changes and understanding associated functional deficits.

Near-term embryos and gravid females of Lusitanian cownose ray (Rhinoptera marginata) in Mersin Bay, eastern Mediterranean Sea

Batoid chondrichthyans are vulnerable to commercial fisheries even though they are often not targeted. A greater understanding of their reproductive biology is important to facilitate their conservation. In February 2013, 89 female and 40 male Lusitanian cownose ray (Rhinoptera marginata) specimens were accidentally caught in Mersin Bay in the eastern Mediterranean Sea. Thirty-six fish were gravid, each bearing one embryo. Of the remaining females, 39 were sexually mature but not gravid and 14 were immature. There were 28 mature and 12 immature males. The average disc width (DW) of both mature females (80.2cm) and males (74.2cm) was significantly higher than that of immature females (60.7cm) and males (60.3cm). For all rays, DW and total weight (TW) were in the range 55.7–98.2cm and 1802–13600g. The DW and TW measured for all 16 female and 20 male embryos were in the range 15.6–29.2cm and 57–281g. Such a large single haul sample, including many gravid specimens and mature males, indicates a schooling formation at capture. The location in Mersin Bay near the estuaries of the Tarsus and Seyhan rivers, and its relative closeness to the sampling location of a previously reported neonate, suggests that this region may be a nursery area for Lusitanian cownose rays in the eastern Mediterranean.

Early Outcomes of Anterior Cervical Discectomy and Fusion Using a Porous PEEK Interbody Fusion Device

Background: Recently, porous surface polyether-etherketone (PEEK) implants have been developed to interact with adjacent endplates. Our goal was to evaluate the efficacy of novel high-strength, porous PEEK interbody fusion devices for anterior cervical discectomy and fusion (ACDF) in patients with symptomatic single-level and multilevel degenerative cervical disc disease at 1 year. Methods: Fifty consecutive patients (31 women, 19 men; average age, 60 years) with degenerative cervical disc disease underwent ACDF using a porous PEEK interbody implant and plate. There were 11 1-level; 23 2-level, and 16 3-level fusions between C3 and C7. Patients were assessed at 1.5, 3, 6, and 12 months. Standardized outcome measures were used to evaluate the patient’s condition before and after surgery. Plain radiographs were used to assess fusion, bony in-growth, subsidence, and implant migration. Sagittal plane angulation was measured on neutral lateral radiographs and determined by Cobb’s criteria. Intradiscal distraction and subsidence were measured by assessing the vertical distance between the midpoints of the adjacent vertebral endplates. Results: At 12 months after surgery, all patients showed improvement in Oswestry Neck Disability Index and neck and arm pain scores. Similarly, at 12 months, all patients showed radiographic fusion. No patient demonstrated motion across the interspace on flexion-extension lateral radiographs. Sagittal plane angulation improved to an average of -6° (range, -2° to -8°) with no measurable evidence of implant migration or subsidence. Average disc space height increased more than 4 mm. No patient had measurable radiographic evidence of a pseudarthrosis or halo formation around the implant. Conclusion: One-year results in this prospective nonrandomized study show that porous-surface PEEK is a clinically viable alternative for improving osseointegration and fusion rates of interbody implants to treat degenerative cervical disc disease.

Classification of optic disc shape in glaucoma using machine learning based on quantified ocular parameters.

PurposeThis study aimed to develop a machine learning-based algorithm for objective classification of the optic disc in patients with open-angle glaucoma (OAG), using quantitative parameters obtained from ophthalmic examination instruments.MethodsThis study enrolled 163 eyes of 105 OAG patients (age: 62.3 ± 12.6, mean deviation of Humphrey field analyzer: -8.9 ± 7.5 dB). The eyes were classified into Nicolela’s 4 optic disc types by 3 glaucoma specialists. Randomly, 114 eyes were selected for training data and 49 for test data. A neural network (NN) was trained with the training data and evaluated with the test data. We used 91 types of quantitative data, including 7 patient background characteristics, 48 quantified OCT (swept-source OCT; DRI OCT Atlantis, Topcon) values, including optic disc topography and circumpapillary retinal nerve fiber layer thickness (cpRNFLT), and 36 blood flow parameters from laser speckle flowgraphy, to build the machine learning classification model. To extract the important features among 91 parameters, minimum redundancy maximum relevance and a genetic feature selection were used.ResultsThe validated accuracy against test data for the NN was 87.8% (Cohen’s Kappa = 0.83). The important features in the NN were horizontal disc angle, spherical equivalent, cup area, age, 6-sector superotemporal cpRNFLT, average cup depth, average nasal rim disc ratio, maximum cup depth, and superior-quadrant cpRNFLT.ConclusionThe proposed machine learning system has proved to be good identifiers for different disc types with high accuracy. Additionally, the calculated confidence levels reported here should be very helpful for OAG care.