Rim Loss Research Articles

Teardrop Alignment Changes After Volar Locking Plate Fixation of Distal Radius Fractures With Volar Ulnar Fragments.

We assessed factors associated with change in radiographic teardrop angle following volar locking plate (VLP) fixation of volarly displaced intra-articular distal radius fractures with volar ulnar fragments (VUF) within the ICUC database. The primary outcome was change in radiographic alignment on follow-up imaging, defined as a change in teardrop angle from intra-operative fluoroscopy greater than 5°. Patients with distal radius fractures treated with a VLP within the ICUC database, an international collaborative and publicly available dataset, were identified. The primary outcome was volar rim loss of reduction on follow-up imaging, defined as a change in radiographic alignment from intra-operative fluoroscopy, teardrop angle less than 50°, or loss of normal radiocarpal alignment. Secondary outcomes were final range of motion (ROM) of the affected extremity. Radiographic Soong classification was used to grade plate position. Descriptive statistics were used to assess variables' distributions. A Random Forest supervised machine learning algorithm was used to classify variable importance for predicting the primary outcome. Traditional descriptive statistics were used to compare patient, fracture, and treatment characteristics with volar rim loss of reduction. Volar rim loss of reduction and final ROM in degrees and as compared with contralateral unaffected limb were also assessed. Fifty patients with volarly displaced, intra-articular distal radius fractures treated with a VLP were identified. Six patients were observed to have a volar rim loss of reduction, but none required reoperation. Volar ulnar fragment size, Soong grade 0, and postfixation axial plate position in relation to the sigmoid notch were significantly associated (P < .05) with volar rim loss of reduction. All cases of volar rim loss of reduction occurred when VUF was 10.8 mm or less. The size of the VUF was the most important variable for predicting volar rim loss of reduction followed by postfixation plate position in an axial position to the sigmoid notch and the number of volar fragments in the Random Forest machine learning algorithm. There were no significant differences in ROM between patients with volar ulnar escape and those without.

Superior segmental optic nerve hypoplasia with normotensive glaucoma: A case report

We report a 27-year-old woman with a cup disk ratio of 0.75:1, with a focal superior neuroretinal rim loss and corresponding nerve fiber layer defect in both eyes. Intraocular pressure was 10 mm Hg in both eyes with normal anterior segment. Perimetry showed inferior arcuate defects in both eyes. A diagnosis of superior segmental optic nerve hypoplasia (SSOH) was made. On follow-up, there was progression in field defects, which were confirmed by repeat field tests, despite normal intraocular pressures. We concluded that there was coexisting normotensive glaucoma (NTG) in this patient.

Technical difficulties of adequate assessment of intraocular pressure in a patient with glaucoma in the long term after corneal refractive surgery (clinical case)

PURPOSE. To demonstrate a clinical case involving difficulties in adequate assessment of intraocular pressure (IOP) in a patient with glaucoma in the long term after LASIK.METHODS. The study describes the case of patient M. of 58 years old with complaints about decreased distance vision in the right eye during the last year. In 2004 the patient underwent LASIK for moderate myopia. In 2018, asymmetry in the parameters of optic nerve head (size of the optic cup to the optic disc ratio (C/D ratio) was revealed: in the right eye — up to 0.7, narrowing of the visual field from nasal to fixation point; in the left eye — 0.5, visual fields without abnormalities. The IOP measured using the Maklakov method in both eyes corresponded to the average statistical norm — 22 mm Hg. The following diagnosis was established: IIA primary open-angle glaucoma in the right eye, IA primary open-angle glaucoma in the left eye. One-time instillations of latanoprost 0.005% eye drops solution was indicated for both eyes. In subsequent years the IOP was 18–20 mm Hg. After 4 years, the IOP according to the Maklakov method: OD — 18 mm Hg; OS — 21 mm Hg (on the hypotensive regimen — instillations of latanoprost 0.005% eye drops solution). In the right eye: C/D ratio 0.85–0.9 with absolute scotoma in the Bjerrum area 5–15° from fixation; in the left eye: C/D ratio 0.9 with neuro retinal rim loss from below, with absolute scotoma in the blind spot area. The stages of primary open-angle glaucoma were ascertained: IIIA in the right eye, IIA in the left eye.RESULTS. Selective laser trabeculoplasty was performed. Brimonidine 0.1% solution was added due to the lack of complete stabilization of the IOP level on a single instillation of latanoprost 0.005%, after that IOP decreased to 19 mm Hg in both eyes.CONCLUSION. It is necessary to carefully assess the condition of the structures of the optic nerve head in patients after LASIK, regardless of the statistically normal IOP values.

RimNet: A Deep Neural Network Pipeline for Automated Identification of the Optic Disc Rim

Accurate neural rim measurement based on optic disc imaging is important to glaucoma severity grading and often performed by trained glaucoma specialists. We aim to improve upon existing automated tools by building a fully automated system (RimNet) for direct rim identification in glaucomatous eyes and measurement of the minimum rim-to-disc ratio (mRDR) in intact rims, the angle of absent rim width (ARW) in incomplete rims, and the rim-to-disc-area ratio (RDAR) with the goal of optic disc damage grading. Retrospective cross sectional study. One thousand and twenty-eight optic disc photographs with evidence of glaucomatous optic nerve damage from 1021 eyes of 903 patients with any form of primary glaucoma were included. The mean age was 63.7 (± 14.9) yrs. The average mean deviation of visual fields was-8.03 (± 8.59). The images were required to be of adequate quality, have signs of glaucomatous damage, and be free of significant concurrent pathology as independently determined by glaucoma specialists. Rim and optic cup masks for each image were manually delineated by glaucoma specialists. The database was randomly split into 80/10/10 for training, validation, and testing, respectively. RimNet consists of a deep learning rim and cup segmentation model, a computer vision mRDR measurement tool for intact rims, and an ARW measurement tool for incomplete rims. The mRDR is calculated at the thinnest rim section while ARW is calculated in regions of total rim loss. The RDAR was also calculated. Evaluation on the Drishti-GS dataset provided external validation (Sivaswamy 2015). Median Absolute Error (MAE) between glaucoma specialists and RimNet for mRDR and ARW. On the test set, RimNet achieved a mRDR MAE of 0.03 (0.05), ARW MAE of 31 (89)°, and an RDAR MAE of 0.09 (0.10). On the Drishti-GS dataset, an mRDR MAE of 0.03 (0.04) and an mRDAR MAE of 0.09 (0.10) was observed. RimNet demonstrated acceptably accurate rim segmentation and mRDR and ARW measurements. The fully automated algorithm presented here would be a valuable component in an automated mRDR-based glaucoma grading system. Further improvements could be made by improving identification and segmentation performance on incomplete rims and expanding the number and variety of glaucomatous training images.

The "Topography" of Glaucomatous Defect Using OCT and Visual Field Examination.

AimTo describe the modifications in the superior and inferior retinal nerve fiber layer (RNFL) thickness regarding the distribution of the VF defects for the horizontal meridians in glaucomatous patients and the differences in the RNFL thickness topography between glaucomatous and healthy subjects.MethodsOne hundred twenty eyes of 91 patients affected by glaucoma and 94 eyes of 51 normal patients were retrospectively reviewed. Computerized 30°VF (Octopus G1 Dynamic strategy) and optical coherence tomography (OCT) ONH and 3D disk analysis were performed in all cases. The RNFL thickness measures analyzed in both groups were superior-nasal (SN), superior-temporal (ST), inferior-nasal (IN), and inferior temporal (IT) sectors. The VFs were classified according to the distribution of the VF defect as for the horizontal meridian in the pattern deviation plot as superior, inferior, predominantly superior, or predominantly inferior.ResultIn the glaucomatous group, 78 eyes (65%) showed a predominantly superior VF defect, while 38 eyes (32%) showed a predominantly inferior VF defect. Fifty-six eyes (46.7%) presented an exclusively superior, and 27/120 eyes (22.5%) presented an exclusively inferior VF defect. In the control group, the thickest RNFL sector was IT. The ST sector showed the thickest RNFL in presence of an exclusive superior VF defect. In case of an exclusive inferior VF defect, the thickest RNFL was the IT sector. VF showing superior defect presented a more altered MD than the VF with an inferior defect.ConclusionGlaucomatous damage affects both the superior and inferior neural rim almost simultaneously. However, the neural rim loss seems to be asymmetric, involving the inferior or superior rim depending on the predominant involvement of the superior or inferior hemifield at the VF test. Particularly, the IT sector appears to be the most compromised in glaucomatous eyes. Therefore, the asymmetry between superior and inferior RNFL could support the diagnosis of glaucoma.How to cite this articlede Paula A, Perdicchi A, Pocobelli A, et al. The “Topography” of Glaucomatous Defect Using OCT and Visual Field Examination. J Curr Glaucoma Pract 2022;16(1):31-35.

88 Pediatric Postburn Ear Reconstruction of Significant Cartilage Defects

IntroductionThe ear is a protruding appendage with multiple functional and aesthetic implications. Literature indicates that up to 40-60% of facial burns involve the ear. Ear burns with considerable tissue loss and sensory deficits can negatively impact quality of life, psychosocial functioning, and physical health. Successful ear reconstruction mitigates these undesirable outcomes. The complex architecture of the external ear presents a formidable surgical challenge after burn injury, when scar tissue, impaired blood supply, and trauma to cartilage all influence reconstructive options. A lack of materials that truly replicate the characteristics of uninjured elastic cartilage also presents a longstanding surgical dilemma. In this retrospective study, the authors highlight the utility of reconstructive techniques to address significant cartilage deficits, including conchal transposition flap, composite graft, costal cartilage graft, and porous polyethylene implant.MethodsA retrospective review was conducted on patients aged 0 to 21 years who underwent cartilage framework reconstruction between January 2004 to January 2021 at a specialized pediatric burn center. Medical records from the hospital’s patient database were screened, and 52 patients (60 ears) who met study criteria were identified. Patient demographics, procedural characteristics, and patient outcomes were analyzed.ResultsFor helical rim cartilage defects, 20 patients (23 ears) with an average age of 15 ± 4 years underwent a conchal transposition flap, which was associated with no major complications. In cases involving repair of small to medium cartilage deficits, 9 patients (9 ears) with an average age of 13 ± 5 years underwent a composite graft, which was associated with one case of infection. A total of 20 patients (23 ears) with an average age of 13 ± 6 years underwent porous polyethylene implantation, which was associated with two cases of exposure and one case of infection. Of these porous polyethylene cases, 20 ears involved helical rim reconstruction and 3 involved total ear reconstruction. Costal cartilage grafting was performed in 4 patients (5 ears) with an average age of 13 ± 5 years and was associated with one case of infection. Costal cartilage grafting was utilized to reconstruct 2 helical rims and 3 total ears.ConclusionsIn cases of focal cartilage defects or medium-sized helical rim cartilage loss, highly aesthetic results and minimal complication rates can be achieved with composite graft or conchal transposition flap. When presented with large to total helical rim loss or total ear loss, either costal cartilage graft or porous polyethylene implantation is typically necessary.

Corneal Hysteresis and Rates of Neuroretinal Rim Change in Glaucoma

To evaluate the impact of corneal hysteresis (CH) as a risk factor for progressive neuroretinal rim loss in glaucoma, as measured by spectral-domain OCT of the Bruch's membrane opening minimum rim width (MRW). Prospective, observational cohort study. The study group included 118 eyes of 70 subjects with glaucoma. The average follow-up time for the cohort was 3.9 ± 1.3 years, with an average of 6.4 ± 2.0 spectral-domain OCT tests, ranging from 4 to12. Corneal hysteresis measurements were acquired at baseline using the Ocular Response Analyzer (Reichert Instruments). Linear mixed models were used to investigate the relationship between the rates of MRW loss and baseline CH. Multivariable analyses adjusted for other putative predictive factors for progression, including mean intraocular pressure (IOP), central corneal thickness (CCT), age, race, and baseline disease severity. Effects of CH on the rate of MRW change over time. Corneal hysteresis had a significant effect on rates of MRW progression over time. Each 1-mmHg lower CH was associated with-0.38 μm/year faster MRW loss (95% confidence interval [CI],-0.70 to-0.06; P=0.019), after adjustment for other predictive factors. The mean IOP was also significantly associated with progression, with-0.35 μm/year (95% CI,-0.47 to-0.23 μm/year) faster MRW change for each 1-mmHg higher pressure (P < 0.001). In the analysis of predictive strength, the mean IOP was the strongest predictive factor (R2=23%), followed by CH (R2= 14%) and baseline disease severity (R2= 6%). Central corneal thickness explained only 3% of the variability in slopes of change in global MRW. Lower CH measurements were associated with faster loss of the neuroretinal rim in glaucoma, as measured by MRW. The predictive ability of CH was superior to that of CCT. These findings suggest that CH is an important parameter to be considered in assessing the risk of glaucoma progression.

Optic Nerve Head and Retinal Abnormalities Associated with Congenital Fibrosis of the Extraocular Muscles.

Congenital fibrosis of the extraocular muscles (CFEOM) is a congenital cranial dysinnervation disorder caused by developmental abnormalities affecting cranial nerves/nuclei innervating the extraocular muscles. Autosomal dominant CFEOM arises from heterozygous missense mutations of KIF21A or TUBB3. Although spatiotemporal expression studies have shown KIF21A and TUBB3 expression in developing retinal ganglion cells, it is unclear whether dysinnervation extends beyond the oculomotor system. We aimed to investigate whether dysinnervation extends to the visual system by performing high-resolution optical coherence tomography (OCT) scans characterizing retinal ganglion cells within the optic nerve head and retina. Sixteen patients with CFEOM were screened for mutations in KIF21A, TUBB3, and TUBB2B. Six patients had apparent optic nerve hypoplasia. OCT showed neuro-retinal rim loss. Disc diameter, rim width, rim area, and peripapillary nerve fiber layer thickness were significantly reduced in CFEOM patients compared to controls (p < 0.005). Situs inversus of retinal vessels was seen in five patients. Our study provides evidence of structural optic nerve and retinal changes in CFEOM. We show for the first time that there are widespread retinal changes beyond the retinal ganglion cells in patients with CFEOM. This study shows that the phenotype in CFEOM extends beyond the motor nerves.

Fixation Stability of Uncemented Acetabular Cups With Respect to Different Bone Defect Sizes

BackgroundIn total hip arthroplasty, acetabular press-fit cups require a proper bone stock for sufficient primary implant fixation. The presence of acetabular bone defects compromises the primary fixation stability of acetabular press-fit cups. The aim of the present study is to determine the fixation stability of a cementless acetabular cup regarding standardized bone defects in an experimental setup. MethodsAn acetabular defect model was developed and transferred to a biomechanical cup-block model. The lack of superior cup coverage was divided into 4 stages of superior rim loss (33%, 50%, 67%, and 83%) in the anterior-posterior direction and into 4 stages of mediolateral wall absence (11%, 22%, 33%, and 50%). This resulted in 11 different defect cavities, which were compared to the intact cavity in push-in and lever-out tests of one press-fit cup design (56 mm outer diameter). Thereby, push-in force, lever-out moment, lever-out angle, and interface stiffness were determined. ResultsThe determined lever-out moments range from 15.53 ± 1.38 Nm (intact cavity) to 1.37 ± 0.54 Nm (83%/50% defect). Smaller defects (33%/11%, 33%/22%, and 50%/11%) reduce the lever-out moments by an average of 33.9% ± 2.8%. ConclusionThe lack of mediolateral acetabular coverage of 50% was assessed as critical for cementless cup fixation, whereby the contact zone between implant and bone in the defect is lost. A lack of 20% to 30% mediolateral coverage appears to be acceptable for press-fit cup fixation in the presence of primary stability. A defect of 50%/50% was identified as the threshold for using additional fixation methods.

A Deep Learning Algorithm to Quantify Neuroretinal Rim Loss From Optic Disc Photographs

To train a deep learning (DL) algorithm that quantifies glaucomatous neuroretinal damage on fundus photographs using the minimum rim width relative to Bruch membrane opening (BMO-MRW) from spectral-domain optical coherence tomography (SDOCT). Cross-sectional study. A total of 9282 pairs of optic disc photographs and SDOCT optic nerve head scans from 927 eyes of 490 subjects were randomly divided into the validation plus training (80%) and test sets (20%). A DL convolutional neural network was trained to predict the SDOCT BMO-MRW global and sector values when evaluating optic disc photographs. The predictions of the DL network were compared to the actual SDOCT measurements. The area under the receiver operating curve (AUC) was used to evaluate the ability of the network to discriminate glaucomatous visual field loss from normal eyes. The DL predictions of global BMO-MRW from all optic disc photographs in the test set (mean ± standard deviation [SD]: 228.8 ± 63.1μm) were highly correlated with the observed values from SDOCT (mean ± SD: 226.0 ± 73.8μm) (Pearson's r= 0.88; R2= 77%; P < .001), with mean absolute error of the predictions of 27.8μm. The AUCs for discriminating glaucomatous from healthy eyes with the DL predictions and actual SDOCT global BMO-MRW measurements were 0.945 (95% confidence interval [CI]: 0.874-0.980) and 0.933 (95% CI: 0.856-0.975), respectively (P= .587). A DL network can be trained to quantify the amount of neuroretinal damage on optic disc photographs using SDOCT BMO-MRW as a reference. This algorithm showed high accuracy for glaucoma detection, and may potentially eliminate the need for human gradings of disc photographs.

CDR based glaucoma detection using fundus images: a review

Glaucoma is an eye disease that occurs when circulation of an eye fluid does not remain normal which in turn increases the intraocular pressure (IOP) in aqueous humour of the human eye. This rise of IOP ultimately damages the optic nerve of an eye and leads to complete or partial vision loss. Several image processing techniques have been developed for the detection of glaucoma on the basis of features such as an optic disc (OD), cup to disc ratio (CDR), retinal nerve fibre layer (RNFL) loss, per papillary atrophy (PPA) and neuroretinal rim loss. This paper presents a review of latest work on the use of the model and non-model approaches to detect glaucoma using OD and CDR as glaucoma features.

Importance of Normal Aging in Estimating the Rate of Glaucomatous Neuroretinal Rim and Retinal Nerve Fiber Layer Loss

To describe longitudinal rates of change of neuroretinal parameters in patients with glaucoma and healthy controls, and to evaluate the influence of covariates. Prospective longitudinal study. Treated patients with glaucoma (n = 192) and healthy controls (n = 37). Global disc margin-based neuroretinal rim area (DMRA) was measured with confocal scanning laser tomography, while Bruch's membrane opening-minimum rim width (BMO-MRW), BMO area (BMOA), and peripapillary retinal nerve fiber layer thickness (RNFLT) were measured with optical coherence tomography at 6-month intervals. Individual rates of change were estimated with ordinary least-squares regression, and linear mixed effects modeling was used to estimate the average rate of change and differences between the groups, and to evaluate the effects of baseline measurement and baseline age on rates of change. Rates of change for each parameter. Subjects were followed for a median (range) of 4 (2-6) years. The proportion of controls who had significant reduction of neuroretinal parameters was 35% for BMO-MRW, 31% for RNFLT, and 11% for DMRA. The corresponding figures for patients with glaucoma were not statistically different (42%, P = 0.45; 31%, P = 0.99; 14%, P = 0.99, respectively). Controls had a significant reduction of BMO-MRW (mean: -1.92 μm/year, P < 0.01) and RNFLT (mean: -0.44 μm/year, P = 0.01), but not DMRA (mean: -0.22×10(-2) mm(2)/year, P = 0.41). After adjusting for covariates, patients with glaucoma had faster, but not statistically different, rates of deterioration compared with controls, by -1.26 μm/year (P = 0.07) for BMO-MRW, -0.40 μm/year (P = 0.11) for RNFLT, and -0.38×10(-2) mm(2)/year (P = 0.23) for DMRA. Baseline BMO-MRW and RNFLT significantly influenced the respective rates of change, with higher baseline values relating to faster reductions. Older age at baseline was associated with a slower reduction in rates of BMO-MRW. Reductions in intraocular pressure were related to increases in BMO-MRW and DMRA. There was a tendency for BMOA to decrease over time (-0.38×10(-2) mm(2)/year; P = 0.04). Age-related loss of neuroretinal parameters may explain a large proportion of the deterioration observed in treated patients with glaucoma and should be carefully considered in estimating rates of change.

Application of the ISNT Rule to Neuroretinal Rim Thickness Determined Using Cirrus HD Optical Coherence Tomography

The study investigated the applicability of the inferior≥superior≥nasal≥temporal neuroretinal rim thickness (ISNT) rule to rim thickness measured using Cirrus high-definition spectral-domain optical coherence tomography (Cirrus HD-OCT) in healthy eyes and eyes with glaucoma. Rim thicknesses of 4 quadrants were investigated using the rim thickness curve of Cirrus HD-OCT for 40 eyes with mild glaucoma (mean deviation ≥ -6 dB), 40 eyes with moderate to advanced glaucoma (mean deviation < -6 dB), and 80 healthy eyes (control group). The relative amount of rim loss in each quadrant in the glaucoma group compared with the control group was calculated. The ISNT rule was considered intact if there was a gradual decrease in rim thickness in the order of inferior≥superior≥nasal≥temporal quadrants. The ISNT rule was intact in 13%, 18%, and 8% of eyes in the control, mild, and moderate to advanced glaucoma groups, respectively, and the distribution was not significantly different among the 3 groups (P>0.05). Relative rim loss in the inferior quadrant of the moderate to advanced glaucoma group (63.8%) was greater than that of the mild glaucoma group (53.6%; P=0.010), whereas rim loss in other quadrants was not significantly different between the 2 groups (P>0.05). The ISNT rule with rim thickness measured using Cirrus HD-OCT has limited clinical value in the diagnosis of glaucoma. There is a topographic difference in inferior rim loss according to the stages of glaucomatous damage.

The effect of dorsal rim loss on the initial stability of the BioMedtrix cementless acetabular cup

BackgroundLoss of dorsal acetabular rim (DAR) is a common sequela to canine hip dysplasia. The purpose of this study is to evaluate the effect of DAR loss on the initial stability of the cementless (BFX) acetabular cup. BFX cups were implanted into foam blocks reamed to resemble acetabulae with simulated 0, 25, 50, and 75% DAR loss. Models were tested in edge loading of the lateral surface of the cup with an indenter, and in centered loading with an articulated femoral prosthesis. Additionally, cups were implanted into paired cadaveric canine hemipelves with either no DAR depletion, or removal of 50% of the DAR, and acutely loaded to failure with an articulated femoral prosthesis.ResultsMean load measured at 1 mm cup displacement during edge loading was not significantly different in foam blocks with loss of 0, 25, 50, and 75% DAR (360 ± 124 N, 352 ± 42 N, 330 ± 81 N, 288 ± 43 N, respectively; P = 0.425). Mean load to failure with centered loads was greatest in blocks with 0% DAR loss (2828 ± 208 N; P < 0.001), but was not significantly different between 25, 50, and 75% DAR loss (2270 ± 301 N, 1924 ± 157 N, 1745 ± 118 N). In cadaveric testing, neither mean load to failure (P = 0.067), stiffness (P = 0.707), nor energy (P = 0.228) were significantly different in control hemipelves and those with 50% depletion of the DAR. Failure in all acetabulae occurred due to acetabular bone fracture at forces in supraphysiologic ranges.ConclusionsBFX cup stability under normal physiologic loads does not appear to be compromised in acetabulae with up to 50% DAR loss.

Glaucomatous Optic Neuropathy Evaluation Project

Glaucoma is a significant health problem for which diagnosis remains suboptimal. Optic disc evaluation, which is fundamental to the diagnosis, is a difficult skill to acquire. To determine the optic disc characteristics that most influence decision making in the assessment of glaucoma likelihood and to ascertain the optic disc features associated with overestimation and underestimation of glaucoma likelihood. This prospective, observational, Internet-based study with multinational participation included 197 ophthalmic clinicians (37 glaucoma subspecialists, 51 comprehensive ophthalmologists, and 109 ophthalmology trainees) from 22 countries who self-registered for the Glaucomatous Optic Neuropathy Evaluation (GONE) Project from December 1, 2008 through June 30, 2010. A series of 42 monoscopic optic disc photographs of healthy and glaucomatous eyes were presented to clinicians using the GONE Project Program. Participants were asked to assess each disc according to 9 conventional topographic features and assign a presumptive grade for glaucoma likelihood. Agreement (κ and weighted κ) among participants for disc signs and glaucoma likelihood and contributions of disc-related factors to overestimation and underestimation of glaucoma likelihood. Ophthalmology trainees and comprehensive ophthalmologists underestimated glaucoma likelihood in a mean (SD) of 22.1% (1.6%) and 23.8% (1.8%) of discs, respectively. Underestimation of vertical cup-disc ratio and failure to identify retinal nerve fiber layer loss, disc hemorrhage, or rim loss were most likely to lead to underestimation of glaucoma. When all 4 features were inaccurately assessed, underestimation of glaucoma likelihood increased to 43.0%. Ophthalmology trainees and comprehensive ophthalmologists overestimated glaucoma likelihood in a mean (SD) of 13.0% (1.2%) and 8.9% (1.3%) of discs, respectively. Overestimation of glaucoma likelihood was associated with overestimation of retinal nerve fiber layer loss, rim loss, vertical cup-disc ratio, disc hemorrhage, and incorrect assessment of disc tilt and was more likely in large discs. Ophthalmology trainees and comprehensive ophthalmologists underestimated glaucoma likelihood in approximately 1 in 5 disc photographs and were twice as likely to underestimate as overestimate glaucoma likelihood. Underestimating the vertical cup-disc ratio and cup shape and missing retinal nerve fiber layer defects and disc hemorrhage were the key errors that led to underestimation. When all 4 parameters were incorrectly assessed, underestimation increased to almost 1 in 2.

Shoulder instability in the setting of bipolar (glenoid and humeral head) bone loss: the glenoid track concept.

An assortment of variables has been used in predicting anterior shoulder instability resulting from pathologic engagement of Hill-Sachs lesions on the glenoid. The glenoid track is a unique biomechanical model that relates both Hill-Sachs and bony Bankart lesions to predict shoulder engagement. We examined the glenoid track concept to determine if it provides a model that unifies glenoid rim and humeral head bone loss in predicting engagement. In this review we addressed two questions: (1) How are humeral head and glenoid rim bony defects and their interactions quantified? (2) Why is the concept of the glenoid track important? We performed a systematic review of the literature using PubMed (MEDLINE) and OVID for biomechanical studies and peer-reviewed articles published until March 2013. Twenty-four studies fit the inclusion criteria. These were subdivided into four anatomic studies, four studies quantifying glenohumeral bone loss, nine studies biomechanically defining shoulder engagement, six studies analyzing current treatment models, and one clinical study to be included in the final review. Data demonstrate pathologic engagement is dependent on the medial margin of the Hill-Sachs lesion traveling outside the glenoid track. The width of the glenoid track decreases accordingly if there is a glenoid defect, making engagement more likely. Most treatment models focus on widening the glenoid track before addressing Hill-Sachs lesions. The glenoid track uses both glenoid and humeral head bone loss to predict subsequent risk of humeral head engagement and possible dislocation. The glenoid track shows us that restoring the track to its natural width should be among the surgeon's first priority in restoring shoulder stability. Humeral head lesions, also known as Hill-Sachs lesions, are surgically addressed when they cause clinical symptoms. Symptoms arise when the medial margin of the defect engages the glenoid track.

Effect of dorsal acetabular rim loss on stability of the zurich cementless total hip acetabular cup in dogs.

To evaluate magnitude and mode of acute load to failure of the Zurich Cementless acetabular cup prosthesis in cadaveric specimens with and without 50% dorsal acetabular rim loss. In vitro mechanical study. Cadaveric hemipelves of adult dogs (n = 8). Each pair of hemipelves was prepared by dissection of surrounding musculature and implantation of a Zurich Cementless acetabular cup prosthesis. One hemipelvis had the dorsal rim left intact (group 1) and the contralateral hemipelvis had 50% of the dorsal rim excised (group 2). Each hemipelvis underwent acute load to failure with an axial load applied through a prosthetic femoral head. Load at failure was compared between hemipelves with and without dorsal rim loss with a paired t-test; P < .05 was considered significant. Mean failure load was not significantly different between group 1 (3,713 ± 362 N) and group 2 (3,640 ± 751 N; P = .8). Bone fracture (n = 6), ventroversion of the cup (1), and absolute failure unreached at 6,000 N (1) occurred in group 1 and bone fracture (6), ventroversion of cup (1), and cup loosening (1) occurred in group 2. Zurich Cementless acetabular cup stability does not appear to be compromised by 50% acetabular rim loss at normal physiologic weight bearing loads. Thus, for this system, modifying procedures such as augmentation of the dorsal acetabular rim or deeper reaming for acetabular bed preparation may not be necessary with up to 50% dorsal rim loss with the Zurich Cementless acetabular cup.

Anatomic vs. Acquired Image Frame Discordance in Spectral Domain Optical Coherence Tomography Minimum Rim Measurements

PurposeTo quantify the effects of using the fovea to Bruch's membrane opening (FoBMO) axis as the nasal-temporal midline for 30° sectoral (clock-hour) spectral domain optical coherence tomography (SDOCT) optic nerve head (ONH) minimum rim width (MRW) and area (MRA) calculations.MethodsThe internal limiting membrane and BMO were delineated within 24 radial ONH B-scans in 222 eyes of 222 participants with ocular hypertension and glaucoma. For each eye the fovea was marked within the infrared reflectance image, the FoBMO angle (θ) relative to the acquired image frame (AIF) horizontal was calculated, the ONH was divided into 30°sectors using a FoBMO or AIF nasal/temporal axis, and SDOCT MRW and MRA were quantified within each FoBMO vs. AIF sector. For each sector, focal rim loss was calculated as the MRW and MRA gradients (i.e. the difference between the value for that sector and the one clockwise to it divided by 30°). Sectoral FoBMO vs. AIF discordance was calculated as the difference between the FoBMO and AIF values for each sector. Generalized estimating equations were used to predict the eyes and sectors of maximum FoBMO vs. AIF discordance.ResultsThe mean FoBMO angle was −6.6±4.2° (range: −17° to +7°). FoBMO vs. AIF discordance in sectoral mean MRW and MRA was significant for 7 of 12 and 6 of 12 sectors, respectively (p<0.05, Wilcoxon test, Bonferroni correction). Eye-specific, FoBMO vs. AIF sectoral discordance was predicted by sectoral rim gradient (p<0.001) and FoBMO angle (p<0.001) and achieved maximum values of 83% for MRW and 101% for MRA.ConclusionsUsing the FoBMO axis as the nasal-temporal axis to regionalize the ONH rather than a line parallel to the AIF horizontal axis significantly influences clock-hour SDOCT rim values. This effect is greatest in eyes with large FoBMO angles and sectors with focal rim loss.

A novel optic nerve photograph alignment and subtraction technique for the detection of structural progression in glaucoma

To highlight changing features over time within a single static image through the auto-alignment and subtraction of serial optic nerve photographs. Subtraction maps were generated from auto-aligned (EyeIC, Narbeth, PA) baseline and follow-up images using Adobe Photoshop software. They demonstrated progressive retinal nerve fibre layer (RNFL) defects, optic disc haemorrhage (DH), neuroretinal rim loss (RL) and peripapillary atrophy (PPA). A masked glaucoma specialist identified features of progression on subtraction map first, then assessed feature strength by comparison with original images using alternation flicker. Control images with no progression and parallax-only images (as determined by flicker) were included. Eighty eyes of 67 patients were used to generate subtraction maps that detected glaucoma progression in 87% of DH (n=28, sensitivity (Se) 82%, specificity (Sp) 98%) and 84% of PPA (n=30, Se 80%, Sp 98%) cases. The lowest rate of detection was seen with RL at 67% (n=31, Se 65%, Sp 100%). The subtraction technique was most sensitive for detecting parallax (n=39, Se 98%, Sp 94%). Features of glaucoma progression appeared equally strong in flicker and subtraction images, but parallax was often enhanced on subtraction maps. Among control images selected for absence of features of glaucomatous change (n=9) in original flicker images, no features were detected on subtraction maps. Auto-alignment and subtraction of serial optic nerve photographs reliably detects features of glaucoma progression with a single static image. Parallax identification may also be facilitated. Auto-alignment and subtraction of serial optic nerve photographs may prove especially useful in education and printed publications when dynamic imaging is not feasible.

Retinal Blood Vessel Positional Shifts and Glaucoma Progression

To determine the characteristics and significance of retinal blood vessel (RBV) positional shifts over time in a cohort of patients with progressive glaucoma. Retrospective cohort study. Baseline and serial stereophotographs from 1 eye of 125 patients with open-angle glaucoma with ≥8 reliable Swedish interactive threshold algorithm standard visual fields (VFs) were included. On the basis of global rates of threshold sensitivity change, patients with glaucoma were divided into groups of minimal (<-0.02 decibels [dB]/year), moderate (-0.02 to-0.65 dB/year), or fast (≥-0.65 dB/year) progression. To determine whether graders' assessments of RBV positional shifts were false-positives, a control group consisting of 33 patients with glaucoma with 2 sets of photographs taken on the same day was included. Masked graders reviewed serial photographs aligned with automated alternation flicker (EyeIC, Narbeth, PA) and assessed them for the presence of any discrete RBV positional shifts (2 graders) and for traditional measures of structural progression (2 graders), including neuroretinal rim loss, parapapillary atrophy progression, and disc hemorrhage (DH). Presence or absence of RBV positional shifts, rates of VF progression, and presence or absence of traditional measures of structural progression. A total of 158 image sets (125 longitudinal and 33 same-day controls) from patients with glaucoma were included. Retinal blood vessel shifts were noted in 33 of 125 (26.4%) longitudinally followed glaucomatous eyes and 2 of 33 (6%) same-day control patients (P= 0.01). Agreement between graders I and II was 90.4% (kappa=0.77; P< 0.001). Eyes with RBV positional change progressed more rapidly than those without (-0.55 vs.-0.29 dB/year; 95% confidence interval [CI], 0.03-0.48); P= 0.03). Retinal blood vessel shift was present in 12.1% of minimal progressors versus 31.5% of moderate and fast progressors (P= 0.04). Rate of VF progression was statistically associated with RBV shift (odds ratio [OR], 2.2; 95% CI, 1.1-4.5; P= 0.03). Other variables significantly associated with RBV shift included neuroretinal rim loss (OR, 21.9; 95% CI, 5.7-83.6; P< 0.001) and DH (OR, 4.6; 95% CI, 1.5-15.5; P< 0.01). A multivariable model revealed that rim loss and DH, but not rate of functional change, were significantly associated with RBV shift. Retinal blood vessel positional shifts occurred in eyes with functionally progressive glaucoma, neuroretinal rim loss, and DH. This is a novel clinical finding that could help identify glaucoma progression or individuals at higher risk for future progression.