Electrical response of retinal ganglion cells in an N-methyl-N-nitrosourea-induced retinal degeneration porcine model

Retinal prosthesis is regarded as the treatment for vision restoration in the blind with retinal degeneration (RD) due to the loss of photoreceptors. A strategy for retinal prosthesis is to electrically activate surviving neurons. The retina’s response to electrical stimulation in a larger RD model has not been studied yet. Therefore, in this study, we investigated electrically evoked retinal responses in a previously validated N-methyl-N-nitrosourea (MNU)-induced porcine RD model. Electrically evoked responses were evaluated based on the number of retinal ganglion cell (RGC) spikes via multichannel recordings. Stimulation pulses were applied to degenerative and wild-type retinas with pulse modulation. Compared to wild-type retinas, degenerative retinas showed higher threshold values of pulse amplitude and pulse duration. The rate of increase in the number of RGC spikes relative to stimulus intensity was lower in degenerative retinas than in normal retinas. In severely degenerated retinas, few RGCs showed electrically evoked spikes. Our results suggest that the degenerative porcine retina requires a higher charge than the normal porcine retina. In the early stage of RD, it is easier to induce RGC spikes through electrical stimulation using retinal prosthesis; however, when the degeneration is severe, there may be difficulty recovering patient vision.

Analysis of Microvasculature in Nonhuman Primate Macula With Acute Elevated Intraocular Pressure Using Optical Coherence Tomography Angiography

Purpose

To investigate responses of macular capillary vessel area density (VAD) of superficial and deep retinal vascular plexuses to elevations in intraocular pressure (IOP) in cynomolgus macaque monkeys using optical coherence tomography angiography (OCTA).

Methods

In five general anesthetized male cynomolgus monkeys, the IOP was increased incrementally by 10 mmHg from baseline (10 mmHg) to 70 mmHg and then decreased back to 10 mmHg (recovery state). Structural OCT (30° × 30°) and OCTA (20° × 15°) centered on the macula were obtained at each IOP and 3, 15, and 30 minutes after recovery. En face images of the superficial vascular complex (SVC) and deep vascular complex (DVC) were extracted, and VAD (%) compared with that at baseline was calculated.

Results

The VADs in the SVC and DVC at baseline and at 30 mmHg IOP were 34.96%, 34.15%, 35.38%, and 30.12%, respectively. The VAD plateaued until 30 mmHg; however, the VAD was affected more in the DVC than in the SVC (P = 0.008) at 30 mmHg. It showed a significant reduction at 40 mmHg (16.52% SVC, P = 0.006; 18.59% DVC, P = 0.012). In the recovery state, the SVC showed full retention of baseline VAD, but the DVC maintained VAD approximately 70% of that at baseline. Structural OCT showed hyperreflectivity in the nuclear layer, retinal swelling, and an undifferentiated ellipsoid zone from 50 mmHg.

Conclusions

Despite physiological autoregulation, perifoveal microcirculation was affected at high IOP ≥ 40 mmHg, especially in the DVC, which explains the pathological mechanism of macular vulnerability in ischemic diseases.

Normative Data of Ocular Biometry, Optical Coherence Tomography, and Electrophysiology Conducted for Cynomolgus Macaque Monkeys

Purpose

To present normative data of optical coherence tomography (OCT) parameters, electrophysiological tests, and optical biometry conducted for cynomolgus monkeys.

Methods

Multimodal examinations were performed for 11 adult cynomolgus monkeys (Macaca fascicularis, weighing 2.6–7.5 kg, aged 45–99 months). A-scan biometry was performed to measure ocular biometry. OCT images were obtained at 30° and 55°. After the pupils were fully dilated, electroretinogram (ERG) and visual evoked potentials (VEP) were recorded with a commercial system using a contact lens electrode.

Results

All cynomolgus monkeys were males. The mean axial length was 17.92 ± 0.34 mm. The central total retinal layer (TRL) and subfoveal choroidal thicknesses were 286.27 ± 18.43 and 234.73 ± 53.93 µm, respectively. The TRL and nerve fiber layer thickness was greater in the nasal than in other quadrants in the Early Treatment Diabetic Retinopathy Study circle in the macula. Peripheral TRL and ganglion cell complex thickness on the temporal outside the vascular arcades were lower than on the other sides. The peak latency of a-wave and b-wave in scotopic and photopic 3.0 ERG was 14.78 ± 1.00 and 32.89 ± 1.81 ms, and 12.91 ± 1.03 and 31.79 ± 2.16 ms, respectively. The n2 wave peak latency of VEP was 15.21 ± 8.07 ms. The a-wave peak latency of ERG and the n2 wave peak latency of VEP negatively correlated with age.

Conclusions

The normative ocular biometric, electrophysiological test, and OCT parametric data of cynomolgus monkeys could serve as reference values for further preclinical studies.

Translational Relevance

We present normative data of cynomolgus monkeys’ eyes, an adequate animal model for preclinical studies.

Changes After a Month Following Micropulse Cyclophotocoagulation in Normal Porcine Eyes

Purpose

To analyze the effects on the uvea, including the pars plicata and ciliary muscle, and retina in normal porcine eyes after performing micropulse transslceral cyclophotocoagulation (MP-TSCPC) with the different energy levels, and conventional continuous wave transslceral cyclophotocoagulation.

Methods

MP-TSCPC was performed in a total of 15 eyes at the different energy levels of 60 J, 120 J, 180 J, 240 J, and 300 J, respectively. Continuous wave transslceral cyclophotocoagulation was performed in three eyes and the other three eyes were controls. The eyes were enucleated after a month following the laser treatment and the uvea and retina were analyzed using hematoxylin and eosin staining and immunohistochemistry staining.

Results

After MP-TSCPC 60 J, the expression of α-smooth muscle actin (α-SMA) and glial fibrillary acidic protein in the ciliary muscle was increased, although there was no structural change in pars plicata. After MP-TSCPC 120 J, partial destruction of the ciliary epithelium was observed in pars plicata, and the retinal thickness was increased. After MP-TSCPC 240 J and 300 J, the structural destruction of the pars plicata and ciliary muscle was observed, and the expression of α-SMA and glial fibrillary acidic protein in pars plicata and the expression of α-SMA in ciliary muscle were increased.

Conclusions

Histologic changes in the uvea and peripheral retina were different based on the energy levels of MP-TSCPC. In particular, MP-TSCPC with low energy levels mainly affected the ciliary muscle, while MP-TSCPC with high energy levels affected both the ciliary muscle and pars plicata. Our results may imply a possibility of intraocular damage with MP-TSCPC in humans.

Translational Relevance

Based on our research, it is possible to infer the possibility of intraocular damage in humans according to the different levels of energy in the clinic.

MORPHOLOGICAL AND ANATOMICAL FEATURES OF TYPE 1 MACULAR NEOVASCULARIZATION TRUNKS IN AGE-RELATED MACULAR DEGENERATION USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

PURPOSE

To evaluate the morphological features of macular neovascularization (MNV) trunks at different layers using optical coherence tomography angiography (OCTA).

METHODS

Type 1 MNV trunks in age-related macular degeneration were retrospectively evaluated at the sub-retinal pigment epithelium (subRPE) and sub-Bruch's membrane (subBM) layers. The detectability and location of the trunks were compared. MNV trunks at the subBM layer on OCTA b-scans were evaluated using a flow overlay. The correlations of the MNV trunk with OCTA and OCT parameters were evaluated.

RESULTS

Among the 63 included eyes, 27 showed core vessels at the subRPE layer and 52 showed MNV trunks at the subBM layer, which were connected with the MNV at the subRPE layer. The locations of the MNV trunks in each layer were different. MNV trunk types at the subBM layer were related to disease duration, distance from the large choroidal vessels, and MNV vessel density. The large choroidal vessel diameter was correlated with the MNV trunk diameter at the subBM layer.

CONCLUSION

MNV trunks at the subBM layer were detected more frequently than distal MNV trunks at the subRPE layer. MNV trunk features at the subBM layer may be related to disease duration and a large choroidal vessel.

Normative Data of Axial Length, Retinal Thickness Measurements, Visual Evoked Potentials, and Full-Field Electroretinography in Female, Wild-Type Minipigs

Purpose

The purpose of this study was to present normative data of optical coherence tomography (OCT), electrophysiological, and ocular biometry parameters and their correlation in minipigs.

Methods

Eighty-eight eyes of 44 minipigs underwent full-field electroretinogram (ERG) recording and ocular biometry. However, 10 eyes of 6 minipigs were excluded because of poor OCT image quality. The thickness of the retinal sublayers was measured on a vertical line at 5 locations with a 1 mm interval from the disc margin to the dorsal periphery and at 10 locations on the visual streak. Visual evoked potentials (VEPs) were measured in 15 eyes of 8 minipigs.

Results

All minipigs were female with a mean age and axial length of 13.83 ± 10.56 months and 20.33 ± 0.88 mm, respectively. The implicit time of the a-wave and b-wave in scotopic 3.0 ERGs was longer than that in photopic 3.0 ERG. The implicit time of the n2-wave and p2-wave in VEP was 25.67 ± 7.41 ms and 52.96 ± 10.38 ms, respectively. The total retinal layer (TRL) and nerve fiber layer (NFL) became thinner near the periphery. The inner retinal sublayers near the visual streak were thicker than those at other locations. Central TRL and NFL thickness on visual streak was 223.06 ± 23.19 µm and 74.03 ± 13.93 µm, respectively. The temporal TRL and NFL on the visual streak were thicker than those on the nasal side.

Conclusions

The normative electrophysiological and OCT parameters used in our study can be used as reference data in further pig studies.

Translational Relevance

This study presents normative data of minipigs, which are adequate animal models for preclinical studies.

Fabrication of GaN/Diamond Heterointerface and Interfacial Chemical Bonding State for Highly Efficient Device Design

The direct integration of gallium nitride (GaN) and diamond holds much promise for high-power devices. However, it is a big challenge to grow GaN on diamond due to the large lattice and thermal-expansion coefficient mismatch between GaN and diamond. In this work, the fabrication of a GaN/diamond heterointerface is successfully achieved by a surface activated bonding (SAB) method at room temperature. A small compressive stress exists in the GaN/diamond heterointerface, which is significantly smaller than that of the GaN-on-diamond structure with a transition layer formed by crystal growth. A 5.3 nm-thick intermediate layer composed of amorphous carbon and diamond is formed at the as-bonded heterointerface. Ga and N atoms are distributed in the intermediate layer by diffusion during the bonding process. Both the thickness and the sp² -bonded carbon ratio of the intermediate layer decrease as the annealing temperature increases, which indicates that the amorphous carbon is directly converted into diamond after annealing. The diamond of the intermediate layer acts as a seed crystal. After annealing at 1000 °C, the thickness of the intermediate layer is decreased to approximately 1.5 nm, where lattice fringes of the diamond (220) plane are observed.

Comparison of Indocyanine Green Angiography and Optical Coherence Tomography Angiography for Polypoidal Choroidal Vasculopathy

Purpose: To assess the diagnostic value of optical coherence tomography angiography (OCTA), and the factors affecting the diagnosis of polypoidal choroidal vasculopathy (PCV) by OCTA and indocyanine green angiography (ICGA). Methods: The numbers and area of polyps, and the presence and area of a branched vascular network (BVN) as revealed by ICGA and OCTA, were retrospectively analyzed in 43 patients with active PCV. The patients were divided into two groups according to whether the number of polyps matched between the two methods: group 1, equal number of polyps revealed by ICGA and OCTA; group 2, different number of polyps revealed by ICGA and OCTA. Results: In 43 PCV patients, the total number of polyps was 1.47 ± 0.83 in ICGA and 1.07 ± 0.91 in OCTA (<i>p</i> < 0.001), and the polyp area was 0.27 ± 0.42 mm² in ICGA and 0.17 ± 0.15 mm² in OCTA (<i>p</i> = 0.023). BVN was found in 33 eyes (76.7%) by ICGA and 29 eyes (67.4%) by OCTA (<i>p</i> < 0.001). The BVN area was 3.61 ± 2.59 mm² in ICGA and 2.74 ± 2.76 mm² in OCTA (<i>p</i> = 0.002). Central retinal thickness and central choroidal thickness were significantly greater in group 2 than group 1 (<i>p</i> < 0.001, respectively). Subretinal fluid (SRF) (<i>p</i> = 0.009) and subretinal hemorrhage (SRH) (<i>p</i> = 0.005) were significantly more prevalent in group 2 than group 1. Polyp height (<i>p</i> = 0.022) and diameter (<i>p</i> = 0.042) were significantly greater in group 2 than group 1. Conclusions: OCTA is a supplementary diagnostic technique for detecting PCV. The presence of SRF and SHR, and large polyp height and diameter, were associated with the polyp detection rate of OCTA for PCV.

GANGLION CELL-INNER PLEXIFORM LAYER THICKNESS IN EYES WITH NONEXUDATIVE AGE-RELATED MACULAR DEGENERATION OF DIFFERENT DRUSEN SUBTYPES

PURPOSE

We sought to investigate the ganglion cell-inner plexiform layer (GCIPL) thickness in eyes with nonexudative age-related macular degeneration.

METHODS

We classified eyes into four categories-pachydrusen, soft drusen, subretinal drusenoid deposit (SDD), and soft drusen with SDD-and compared the baseline mean macular GCIPL thickness according to the Early Treatment Diabetic Retinopathy Study grid and its change between groups.

RESULTS

We classified 53, 29, 36, and 34 eyes into the four categories, respectively. The mean GCIPL thickness values in the 3-mm area were 82.61 ± 9.54 µm for the pachydrusen group, 79.11 ± 10.26 µm for the soft drusen group, 77.72 ± 6.04 µm for the SDD group, and 71.63 ± 8.69 µm for the soft drusen with SDD group (P < 0.001). The soft drusen with the SDD group showed a greater change in GCIPL thickness (-2.50 ± 0.29 µm/year) in the 3-mm area as compared with the pachydrusen group (-0.18 ± 0.35 µm/year), soft drusen group (-0.55 ± 0.36 µm/year), and SDD group (-0.55 ± 0.37) (all P < 0.001).

CONCLUSION

The GCIPL thickness varied according to the type of nonexudative age-related macular degeneration. The thinner baseline GCIPL and its greater change in eyes with soft drusen with SDD may suggest that these eyes are experiencing more prominent neuroretinal degeneration in the central 3-mm area than those in the other groups.

Contrast, visibility, and color balance between the microscope versus intracameral illumination in cataract surgery using a 3D visualization system

Purpose:

To compare image resolution and depth between the microscope versus intracameral illumination images during 3D heads-up cataract surgery.

Methods:

We collected 25 consecutive patients who had cataract surgery using the 3D viewing system. Based on bright, contrast, visibility, and color balance, the digital images (RGB color and three monochromes) extracted at the same point of the procedures were compared between the two illuminations.

Results:

Contrast values of green and blue channels except for red channel and visibility values of all three channels were higher in the intracameral illumination images than in the microscope images (P < 0.001, t-test). Color balance values of both green/red and blue/red were higher in the intracameral illumination images than in the microscope images (P < 0.001, t-test).

Conclusion:

The digital images in the digitally assisted cataract surgery were enhanced by using the intracameral illumination. Considering the contrast and color balance in the 3D cataract surgery, the intracameral illumination may be better than the microscope illumination.

Demographic and Multimodal Imaging Features of Macular Telangiectasia Type 2: Korean Macular Telangiectasia Type 2 Study - Report No. 2

Purpose: To investigate the demographic and multimodal imaging features of macular telangiectasia (MacTel) type 2 in Korea and their relationship with visual acuity and the clinical stage.Methods: A retrospective multicentre cross-sectional study was conducted in six tertiary hospitals in Korea and the study included 84 patients. Demographic data and imaging data of fundus photography, fundus autofluorescence (FAF), confocal blue-light reflectance (CBR), fluorescein angiography (FAG), and optical coherence tomography (OCT) were collected.Results: The Korean patients with MacTel type 2 were predominantly female (75%), and the mean logMAR visual acuity was 0.282 ± 0.280 at initial presentation. Most commonly presented signs were the loss of retinal transparency in fundus photographs (68.3%); increased autofluorescence in FAF (83.6%); increased blue reflectance involving the centre in CBR (68.0%); telangiectatic vessels in FAG (88.2%); and hyporeflective cavities in OCT (77.7%). The eyes diagnosed in the first half of the study period (2009-2014) showed a tendency to be diagnosed at more advanced severe stages than those diagnosed in the second half of the study period (2015-2019), using new severity scales based on FAG, FAF and OCT findings.Conclusion: The clinical features of MacTel type 2 in Korean patients assessed by newer imaging modalities suggest that Korean patients and the Caucasian-dominant population show similar presentations. This study showed that MacTel type 2 can be diagnosed in the earlier phase of the disease by using new imaging modalities and through better understanding of the disease.

An experimental pig model with outer retinal degeneration induced by temporary intravitreal loading of N-methyl-N-nitrosourea during vitrectomy

We aimed to develop an outer retinal degeneration pig model induced by temporary intravitreal loading of N-methyl-N-nitrosourea (MNU) during vitrectomy. In a preliminary experiment involving 5 mini-pig cases to determine the appropriate concentration of MNU, the vitreous cavity of each eye was filled with 4, 8, 10, 12, or 16 mg/mL MNU for 10 min, which was then replaced with a balanced salt solution. Multimodal examinations including spectral-domain optical coherence tomography (OCT) images and full-field electroretinography (ffERG) were obtained at baseline and week 2, week 6, and week 12. The retinal degeneration was classified according to the amplitudes of a dark adaptive (DA) 10.0 a-wave amplitude. The degree of moderate retinal degeneration was defined as DA 10.0 a-wave amplitude ≥ 10% and < 60% of baseline amplitude. The degree of severe degeneration was defined as DA 10.0 a-wave amplitude < 10% of baseline amplitude, noise, or flat signal. Hematoxylin and eosin staining and immunohistochemistry were performed at week 12. The main experiments were conducted first with 10 cases of 5 mg/mL and later with 13 cases of 10 mg/mL. In the preliminary experiment, degree of outer retinal degeneration increased with MNU concentration. Use of 4, 8, 10, 12, and 16 mg/mL MNU showed no, moderate, severe, severe, and atrophic changes, respectively. In the main experiments, there were 9 cases of moderate retinal degeneration and 1 case of severe degeneration in 5 mg/mL MNU group. Two cases of moderate degeneration and 11 of severe degeneration were recorded in 10 mg/mL group. Mean thickness of total retina, inner nuclear layer, and outer nuclear layer decreased at week 2 in both groups. The mean amplitudes on ffERG decreased at week 2. The ffERG and OCT findings did not change from week 2 to week 6 or week 12. The results of staining supported those of ffERG and OCT. Temporal MNU loading in a vitrectomized pig-eye model induced customized outer retinal degeneration with changing the concentration of MNU.

Ab-interno surgical technique for the implantation of a wireless subretinal prosthesis in mini-pigs

We sought to describe the surgical techniques required in the ab-interno method to implant subretinal prostheses in mini-pigs and suggest tips to facilitate optimal outcomes. During vitrectomy, the use of valved trocar cannulas was essential to stabilize the detached retina and implanted chip. As a first step in retinal detachment, a 23-gauge cannula with very small amount of viscoelastic material was used to establish the retinal hole and promote retinal detachment. Then, balanced salt solution was applied to increase the retinal detachment and diathermy was used to make opening for subretinal prosthesis. For easy positioning of the subretinal prosthesis, a curved laser probe was adopted when handling the subretinal prosthesis under the retina. After surgery, the sclerotomy sites were tightly sutured to prevent silicone oil leakage. Without special equipment, such as a 41-gauge tip, retinal detachment could be induced easily, while the prosthesis was also successfully inserted and manipulated under the retina without an iatrogenic retinal tear. Two weeks after the operation, the oil fully occupied the intraocular volume without leakage. The subretinal prosthesis remained stable without complication. Understanding the principle of the ab-interno method and considering several tips for improving surgical access may help to enhance surgical success rates of subretinal prostheses implantation.

Light exposure from microscope versus intracameral illumination during cataract surgery

Purpose:

To evaluate light exposure from microscope versus intracameral illuminations to patient's and surgeon's retina during cataract surgery.

Methods:

Thirty consecutive patients who had cataract surgery using microscope and intracameral illuminations. At the point of the ocular of an operating microscope, optical illuminance and irradiance from the microscope illumination (60, 40, 20% intensity) and the intracameral illumination (60% intensity) were measured using a light meter and a spectrometer at a pause after lens capsule polishing in cataract surgery.

Results:

Average illuminance (lux) was 1.46, 0.66, 0.27, and 0.1 from 60%, 40%, 20% intensity microscope illuminations and 60% intracameral illumination. Average total spectral irradiance (μW/cm2) was 1.25, 0.65, 0.26, and 0.03 from 60%, 40%, 20% intensity microscope illuminations and 60% intracameral illumination.

Conclusion:

Microscope ocular illuminance and irradiance during cataract surgery were higher in the microscope illumination than in the intracameral illumination. It suggests that light exposure reaching patient's and surgeon's retina during cataract surgery is lower in the intracameral illumination than in the microscope illumination.

Clinical Characteristics of Developmentally Delayed Children based on Interdisciplinary Evaluation

The aim of this study is to examine the clinical characteristics of children suspected to have neurodevelopmental disorders and to present features that could be helpful diagnostic clues at the clinical assessment stage. All children who visited the interdisciplinary clinic for developmental problems from May 2001 to December 2014 were eligible for this study. Medical records of the children were reviewed. A total of 1,877 children were enrolled in this study. Most children were classified into four major diagnostic groups: global developmental delay (GDD), autism spectrum disorder (ASD), developmental language disorder (DLD) and motor delay (MD). GDD was the most common (43.9%), and boys were significantly more predominant than girls in all groups. When evaluating the predictive power of numerous risk factors, the probability of GDD was lower than the probability of ASD among boys, while the probability of GDD increased as independent walking age increased. Compared with GDD and DLD, the probability of GDD was increased when there was neonatal history or when the independent walking age was late. Comparison of ASD and DLD showed that the probability of ASD decreased when a maternal history was present, whereas the probability of ASD increased with male gender. To conclude, the present study revealed the clinical features of children with various neurodevelopmental disorders. These results are expected to be helpful for more effectively flagging children with potential neurodevelopmental disorders in the clinical setting.

OCT Angiography Features of Neovascularization as Predictive Factors for Frequent Recurrence in Age-Related Macular Degeneration

PURPOSE

To investigate the features of neovascularization (NV) in eyes with neovascular age-related macular degeneration using optical coherence tomography angiography (OCTA) according to the treatment interval of intravitreal aflibercept injection (IVI).

DESIGN

Retrospective, interventional, comparative case series.

METHODS

Patients with type 1 NV treated with the "pro re nata" regimen after 3 loading IVI were classified into 2 groups based on the numbers of treatments during 12 months, specifically a stable group who required fewer than 2 injections and an unstable group who required more than 3 injections. Quantitative features of OCTA including NV area, NV length, NV density, endpoint density (open-ended vessels per unit length), junction density (vessel junction per unit length), lacunarity, and largest vessel caliber were compared between the 2 groups.

RESULTS

Among 71 eyes, 38 and 33 eyes were classified into the stable and unstable groups, respectively. The unstable group had higher endpoint densities (stable vs unstable: 2.72 vs 3.18; P = .03) and higher levels of lacunarity (0.177 vs 0.211; P = .028). The area, density, length of NV, junction density, and largest vessel caliber were not different between the 2 groups (P = .057, P = .184, P = .062, P = .160, and P = .473, respectively). Endpoint density was correlated with the unstable group in both univariate and multivariate analyses (P = .004, P = .002, respectively). A predictive model with an endpoint index demonstrated a sensitivity of 93.75% and a negative predictive value of 89.47% for the unstable group.

CONCLUSIONS

The characteristics of NV in eyes of exudative age-related macular degeneration with type 1 NV were different according to treatment requirements. Identifying the features of NV on OCTA might be helpful for predicting clinical outcomes and optimal treatment intervals.

Humeral shaft fracture and radial nerve palsy in Korean soldiers: focus on arm wrestling related injury

INTRODUCTION

Humeral shaft fractures can lead to radial nerve injury and may require surgery and rehabilitation. We determined the causative events of humeral fracture, including arm wrestling, in young Korean soldiers and examined whether humeral fracture is related to demographic characteristics and the presence of radial nerve palsy.

METHODS

We reviewed 7.5 years (July 2012 to June 2019) of medical records covering patients who had experienced a humeral shaft fracture after entering military service and had received surgery for open reduction and internal fixation. Data were obtained on basic demographics, initial event provoking the fracture, presence of radial nerve palsy, initial and follow-up severity of the weakness, and any discharge from military service because of prolonged radial nerve palsy.

RESULTS

Of 123 cases, arm wrestling was the leading cause (52.8%). A high energy injury, such as falling from a height (11.4%), and sports related slips (10.6%) were other causes. All humeral shaft fractures caused by forceful contraction were spiral, while 40% of the fractures caused by external force related events were of a transverse type. The percentage of left-sided fractures was significantly higher for fractures arising from an external force than in those caused by forceful contraction related events. Radial nerve palsy was found in 34 patients (27.6%), and 16 were discharged from the military because of prolonged radial nerve palsy 6 months after the fracture. The causative events and other factors did not affect the presence of radial nerve palsy.

CONCLUSION

Arm wrestling was the leading cause of humeral fracture in young Korean soldiers but the chance of developing comorbid radial nerve palsy did not differ from that of other causes. These epidemiologic findings in this young active group may help in understanding the causes of humeral shaft fracture in soldiers and in the wider young population.

Elective neck dissection versus observation for early-stage oral squamous cell carcinoma: Systematic review and meta-analysis

INTRODUCTION

Oral squamous cell carcinoma (OSCC) is the seventh most common cancer globally, and has been identified as a growing health concern. This study aims to evaluate the current literature comparing elective neck dissection to observation in the treatment of early-stage tongue SCC, focusing on nodal recurrence, overall survival, disease specific survival statistics from randomised controlled trials comparing the two interventions.

METHODS

Systematic review and meta-analysis was conducted according to PRISMA guidelines. The odds ratio (OR) was used as a summary statistic.

RESULTS

From 8 studies, there was a total of 372 cases of recurrence, 98 (15.1%) in END group and 274 (41.5%) in the Observation group. There was a significantly lower rate of recurrence in the END group compared to observation (OR 0.25, 95% CI 0.16-0.39, I² = 54%, P < 0.00001). END was associated with higher overall survival rates when compared with observation (OR 1.95, 95% CI 1.40-2.73, I² = 14%, P < 0.0001). END was also associated with higher disease-specific survival compared with observation (OR 1.88, 95% CI 1.21-2.93), I² = 47%, P = 0.005), with no significant heterogeneity noted.

CONCLUSIONS

END was associated with significantly lower recurrence rates and higher overall and disease-specific survival compared to a conservative observation approach in early-stage oral SCC with clinically N0 neck.

European Position Paper on Rhinosinusitis and Nasal Polyps 2020

The European Position Paper on Rhinosinusitis and Nasal Polyps 2020 is the update of similar evidence based position papers published in 2005 and 2007 and 2012. The core objective of the EPOS2020 guideline is to provide revised, up-to-date and clear evidence-based recommendations and integrated care pathways in ARS and CRS. EPOS2020 provides an update on the literature published and studies undertaken in the eight years since the EPOS2012 position paper was published and addresses areas not extensively covered in EPOS2012 such as paediatric CRS and sinus surgery. EPOS2020 also involves new stakeholders, including pharmacists and patients, and addresses new target users who have become more involved in the management and treatment of rhinosinusitis since the publication of the last EPOS document, including pharmacists, nurses, specialised care givers and indeed patients themselves, who employ increasing self-management of their condition using over the counter treatments. The document provides suggestions for future research in this area and offers updated guidance for definitions and outcome measurements in research in different settings. EPOS2020 contains chapters on definitions and classification where we have defined a large number of terms and indicated preferred terms. A new classification of CRS into primary and secondary CRS and further division into localized and diffuse disease, based on anatomic distribution is proposed. There are extensive chapters on epidemiology and predisposing factors, inflammatory mechanisms, (differential) diagnosis of facial pain, allergic rhinitis, genetics, cystic fibrosis, aspirin exacerbated respiratory disease, immunodeficiencies, allergic fungal rhinosinusitis and the relationship between upper and lower airways. The chapters on paediatric acute and chronic rhinosinusitis are totally rewritten. All available evidence for the management of acute rhinosinusitis and chronic rhinosinusitis with or without nasal polyps in adults and children is systematically reviewed and integrated care pathways based on the evidence are proposed. Despite considerable increases in the amount of quality publications in recent years, a large number of practical clinical questions remain. It was agreed that the best way to address these was to conduct a Delphi exercise . The results have been integrated into the respective sections. Last but not least, advice for patients and pharmacists and a new list of research needs are included. The full document can be downloaded for free on the website of this journal: http://www.rhinologyjournal.com.

Clinical Implications of Suspended Scattering Particles in Motion Observed by Optical Coherence Tomography Angiography

The objective of this study was to investigate the relationship between suspended scattering particles in motion (SSPiM) in optical coherence tomography angiography (OCTA) and treatment response in diabetic macular edema (DME). We retrospectively reviewed the medical records of patients diagnosed with DME who had undergone intravitreal injection. The optical density ratio (ODR) of the intraretinal cyst and the numbers of hyperreflective foci from OCT images and SSPiM from OCTA images were compared, and their association with treatment response was analyzed. Forty-five eyes from 45 patients were included in this study. Twenty-four patients were treated with anti-vascular endothelial growth factor, and 21 patients were treated with a steroid. Binary logistic regression model showed that SSPiM in OCTA images was associated with hyperreflective foci numbers (P = 0.038) and mean ODR of the intraretinal cyst (P = 0.006). Linear regression model showed that SSPiM in the inner nuclear layer was related to treatment response (P = 0.006). SSPiM on OCTA images is related to the poor structural response to treatment in DME.

367 Combinational use of sodium butyrate and phytogenics on intestinal health of nursery pigs

The effects of encapsulated sodium butyrate (SB), phytogenics (PH), or a combination were studied on intestinal health of nursery pigs. Phytogenics were blends of dry herbs and essential oil components. Forty-eight weaned pigs (21-d-old; 6.9 ± 0.6 kg BW) were individually housed, blocked by initial BW and sex, allotted to 4 dietary treatments (n = 12) in a RCBD, and fed for 33-d (P1: 0–7; P2: 7–19; and P3: 19–33). Treatments were arranged by 2 factors: SB (P1: 0.2% and P2: 0.1%) and PH (P3: 0.033%). Diets were formulated to meet or exceed NRC (2012) nutrient requirements and pigs were fed ad libitum. For each phase, ADG, ADFI, and G:F were measured. Fecal scores were assessed during d 3–19 and d 26–33. Blood samples were drawn in P2 and P3 to measure tumor necrosis factor alpha (TNF-α), IL-6, and immunoglobulin G (IgG). Four pigs at P2 and 8 pigs in P3 from each treatment were euthanized to collect jejunal tissue, jejunal mucosa, and ileal digesta to measure gut histology, TNF-α, IL-6, myeloperoxidase (MPO), malondialdehyde (MDA), and protein carbonyl. Data were analyzed using PROC MIXED of SAS. Fixed effects were treatments and random effects were blocks. In P2 and P1-2, SB decreased (P &lt; 0.05) ADFI whereas no effect on ADG and G:F. In P2, SB tended to decrease (P = 0.063) villus height to crypt depth ratio (VH:CD) whereas increased (P &lt; 0.05) enterocyte proliferation in P3. In P3 and overall, PH increased (P &lt; 0.05) G:F. No changes were found in TNF-α, IL-6, MPO, MDA, IgG, and protein carbonyl. Conclusively, SB and a combinational use of SB and PH showed minimal effects on growth performance and gut health when added to the diets of nursery pigs. However, PH supplementation increased feed efficiency of nursery pigs during 19–33 d post-weaning.

137 Effects of dietary supplementation with xylanase and probiotics on growth performance and gut health of newly weaned pigs

This study was to evaluate the supplemental effects of xylanase and probiotics on growth performance and gut health of newly weaned pigs. One hundred and forty-four pigs at 3 weeks of age with an initial body weight (BW) at 6.47 ± 0.03 kg were allotted (4 pigs per pen) to 3 dietary treatments based on a randomized complete block design with sex (gilts and barrow) and initial BW as blocks. The treatments were CON (no supplement), XYL (xylanase at 10,000 XU/kg, Xylamax, BRI, Durham, NC), and PRO (Bacillus spp. 6 x 109 CFU/kg plus xylanase 10,000 XU/kg, EnzaPro, BRI). All diets met the NRC (2012) requirements in 3 phases (P1 for 7 d, P2 for 14 d, and P3 for 14 d). The ADG, ADFI, and G/F were measured weekly. On d 21, 1 pig representing a median BW of each pen was euthanized to collect jejunal samples to measure the immune and oxidative stress status, microbiome, and histology. Data were analyzed using the MIXED procedure of SAS. Treatment was a fixed effect and blocks were random effects. There were no fixed effects among treatments on growth performance, immune and oxidative stress status, and histology. Use of xylanase increased (P &lt; 0.05) the Chao1 index in jejunal mucosa of pigs (24.6 to 29.5). Relative abundance of the Enterobacteriaceae in jejunal mucosa tended to decrease (P = 0.083) with the use of xylanase (16.2 to 1.6%). The PRO increased (P &lt; 0.05) the relative abundance of Mitsuokella compared with others treatments (0.9 vs. 4.8%). In conclusion, supplementation of xylanase or Mitsuokella can enhance the microbiome in jejunal mucosa by increasing the diversity and beneficial bacterial abundance, whereas by reducing pathogenic bacterial abundance without affecting the growth performance, histology, immune, and oxidative stress status.