Mm Of Change Research Articles

Changes in Fracture Shortening Occur in the First 2 Weeks Following Completely Displaced Adolescent Clavicle Fractures.

Shortening of midshaft clavicle fractures has been described as a critical fracture characteristic to guide treatment. The degree to which shortening may change in the initial weeks following injury has not been well studied. The purpose of this study was to evaluate the change in shortening of adolescent clavicle fractures in the first 2 weeks following injury. This was a multicenter study of prospectively collected data, which was acquired as a part of a cohort study of adolescent clavicle fractures. A consecutive series of patients 10 to 18 years of age with completely displaced diaphyseal clavicle fractures with baseline radiographs 0 to 6 days from the date of injury, as well as 7 to 21 days from the date of injury, were included. Measurements of end-to-end (EES) and cortex-to-corresponding-cortex (CCS) shortening were performed. A total of 142 patients were included. Baseline radiographs were obtained at a mean of 1.0 day following injury with mean EES of 22.3mm, and 69% of patients demonstrating > 20mm of shortening. Follow-up radiographs obtained at a mean of 13.8 days postinjury demonstrated a mean absolute change in EES of 5.4mm. Forty-one percentage of patients had >5mm of change in EES. When analyzing changes in shortening relative to the specific threshold of 20mm, 18 patients (41%) with <20mm EES increased to ≥20mm EES, and 19 patients (19%) with ≥20mm EES decreased to <20mm EES at 2-week follow-up. Clinically significant changes in fracture shortening occurred in 41% of adolescents with completely displaced clavicle fractures in the first 2 weeks after injury. In 26% of patients, this resulted in a change from above or below the commonly used shortening threshold of 20mm, potentially altering the treatment plan by many providers. There is no evidence to suggest that adolescent clavicle fracture shortening affects outcomes, and as such, the authors do not advocate for the use of this parameter to guide treatment. However, among physicians who continue to use this parameter to guide treatment, this study supports that repeat radiographic assessment 2 weeks postinjury may be a better measure of the true shortening of this common adolescent injury. Level IV-case series.

Accuracy of the Lesser Trochanter Profile as a Marker of Femoral Rotation: Computed Tomography-Based Study of 1,722 Femora.

The lesser trochanter (LT) profile is an often-used marker for proximal femoral rotation, particularly during the operative fixation of femoral fractures. Previous studies have come to conflicting conclusions about its reliability for this purpose. The SOMA (Stryker Orthopaedic Modeling and Analytics) database (Stryker) was used to identify 1,722 computed tomographic (CT) scans of whole femora. Each femur was taken through an 80° rotational arc in 2.5° increments, and the LT profile was constructed for each position. These 56,826 LT profile measurements were then correlated with the femoral rotation. Across the arc of motion studied, the LT correlated weakly with proximal femoral rotation (R 2 = 0.32). There was a 35° arc, between 10° and 45° relative external rotation of the proximal femur, within which the LT profile only changed by 1 mm. The mean overall femoral anteversion was 21.2°, and women tended to have more femoral anteversion (23.9°) than men (19.2°). On average, men had a 1.6-mm more prominent LT than women. Side-to-side differences in femoral anteversion as well as LT position and size were not significant or were clinically unimportant. A large-scale, CT-based study shows that the LT profile is a less reliable marker of proximal femoral rotation than previously thought. This is true particularly if there is relative external rotation of the proximal femur, where the proximal femur can undergo up to 35° of rotation before 1 mm of change in the LT profile occurs. Care must be taken to check other markers of rotation such as by clinical examination during fixation of femoral fractures and not rely solely on the LT profile. In the largest study of its kind, this CT-based study of 56,826 LT profile measurements found that when the proximal femur is externally rotated, the LT profile becomes an unreliable marker of rotation, which can lead to excessive internal rotation of the distal fracture fragment. The LT profile should be used with caution, and confirmation of rotation by other means is recommended.

Retrospective Analysis of a Clinical Algorithm for Managing Childhood Myopia Progression.

As the myopia epidemic unfolds, there is growing urgency to identify and implement effective interventions to slow myopia progression. This investigation evaluated the effectiveness of an evidence-based myopia treatment algorithm in a clinical setting among 342 consecutive children. This study aimed to evaluate effectiveness of a clinical treatment algorithm for myopia progression in children. A retrospective cohort analysis was performed using data from myopic children treated for at least 1 year with a defined treatment algorithm incorporating orthokeratology, multifocal lenses, and atropine. The main outcome measures were the percentage of children experiencing ≤0.25 D of myopic cycloplegic spherical equivalent autorefraction (CSER) progression and ≤0.10 mm of axial elongation at 1, 2, and 3 years. The secondary outcome measures were the cumulative absolute reduction of axial elongation values derived from age- and ethnicity-matched virtual control data at 1, 2, and 3 years. Mean annual CSER change values (excluding orthokeratology) were -0.30, -0.20, and -0.13 D at 1, 2, and 3 years, respectively, with 59, 56, and 60% of patients demonstrating ≤0.25 D of change over the prior year. Mean annual axial elongation values were 0.13, 0.12, and 0.09 mm at 1, 2, and 3 years, respectively, with 52, 46, and 65% of patients demonstrating ≤0.10 mm of change over the prior year. The cumulative absolute reduction of axial elongation values were 0.11, 0.20, and 0.29 mm for 1, 2, and 3 years, respectively. The treatment algorithm demonstrated effective control of CSER and axial length in a diverse group of progressive myopic children, supporting its use for the clinical management of childhood myopia.

Does Shortening Change in the First 2 Weeks Following Completely Displaced Adolescent Clavicle Fractures?

Background:Shortening of midshaft clavicle fractures has been described as a critical fracture characteristic to guide treatment in clavicle fractures. However, the degree to which shortening may actually change in the weeks following injury has not been well studied.Purpose:The purpose of this study was to evaluate the potential change in shortening of adolescent clavicle fractures in the first 2 weeks following injury.Methods:This was an IRB-approved multi-center study of prospectively collected data which was acquired as a part of a larger cohort study evaluating functional outcomes of adolescent clavicle fractures. A consecutive series of patients ages 10 – 18 years of age with completely displaced diaphyseal clavicle fractures with a baseline AP clavicle radiograph (0-6 days from date of injury) and a follow-up AP clavicle radiograph (7 – 21 days from date of injury) were included. Measurements of end-to-end clavicle shortening were performed with validated techniques.Results:142 patients met inclusion criteria. Baseline radiographs were obtained at a mean of 1 day +/- 1.7 days following injury. Mean baseline shortening was 22.3mm +/- 0.6mm. 69% of patients had >/= 20mm of shortening. Follow-up radiographs were obtained at a mean of 13.8 days +/- 3.8 days post-injury and demonstrated a mean change in shortening of 5.4mm, compared to baseline films. 41% of patients had >5mm of change in shortening and 15% of patients had >10mm change in shortening. Using a threshold shortening of 20mm, 26% of patients had a change from baseline to follow-up from either above to below 20mm or below to above 20mm. This includes 28% of patients with 20-25mm of shortening at baseline that were less than 20mm at follow-up.Conclusion:Significant changes in fracture shortening occur in many adolescents with completely displaced clavicle fracture in the first 3 weeks. More than a quarter of patients demonstrated a drop from above to below 20mm, a commonly used threshold for surgical decision making. While there is minimal evidence to suggest that shortening influences outcomes following this fracture in adolescent sub-populations, the findings of this study support repeat radiographic assessment 2-3 weeks post-injury prior to making definitive treatment decisions.

Using neural networks to extend cropped medical images for deformable registration among images with differing scan extents.

Missing or discrepant imaging volume is a common challenge in deformable image registration (DIR). To minimize the adverse impact, we train a neural network to synthesize cropped portions of head and neck CT's and then test its use in DIR. Using a training dataset of 409 head and neck CT's, we trained a generative adversarial network to take in a cropped 3D image and output an image with synthesized anatomy in the cropped region. The network used a 3D U-Net generator along with Visual Geometry Group (VGG) deep feature losses. To test our technique, for each of the 53 test volumes, we used Elastix to deformably register combinations of a randomly cropped, full, and synthetically full volume to a single cropped, full, and synthetically full target volume. We additionally tested our method's robustness to crop extent by progressively increasing the amount of cropping, synthesizing the missing anatomy using our network, and then performing the same registration combinations. Registration performance was measured using 95% Hausdorff distance across 16 contours. We successfully trained a network to synthesize missing anatomy in superiorly and inferiorly cropped images. The network can estimate large regions in an incomplete image, far from the cropping boundary. Registration using our estimated full images was not significantly different from registration using the original full images. The average contour matching error for full image registration was 9.9mm, whereas our method was 11.6, 12.1, and 13.6mm for synthesized-to-full, full-to-synthesized, and synthesized-to-synthesized registrations, respectively. In comparison, registration using the cropped images had errors of 31.7mm and higher. Plotting the registered image contour error as a function of initial preregistered error shows that our method is robust to registration difficulty. Synthesized-to-full registration was statistically independent of cropping extent up to 18.7cm superiorly cropped. Synthesized-to-synthesized registration was nearly independent, with a -0.04mm of change in average contour error for every additional millimeter of cropping. Different or inadequate in scan extent is a major cause of DIR inaccuracies. We address this challenge by training a neural network to complete cropped 3D images. We show that with image completion, the source of DIR inaccuracy is eliminated, and the method is robust to varying crop extent.

Open Rhinoplasty

Rhinoplasty is often considered the black box of plastic surgery. This apprehension can be overcome by having a fine-tuned understanding of nasal anatomy, developing an appreciation for nasal aesthetics, and becoming well-versed in the array of surgical techniques available to address specific cosmetic and functional concerns. Technical care and finesse are required in this type of surgery, where even 1 mm of change can result in a profound difference. Nasal function must also be assessed and preserved during rhinoplasty. Aside from these technical points, it is equally important to accurately and thoroughly understand each patient’s goals and to communicate the realistic outcomes and limitations of what can be done through surgery. Key words: open rhinoplasty, nasal anatomy, nasofacial analysis, rhinoplasty techniques, rhinoplasty preoperative evaluation, rhinoplasty postoperative management, lateral nasal osteotomies, nasal tip grafts, nasal tip suture techniques This review contains 23 figures, 2 tables, and 43 references.

A single-center retrospective analysis of 3- or 4-level anterior cervical discectomy and fusion: surgical outcomes in 66 patients.

Anterior cervical discectomy and fusion (ACDF) is a safe and effective intervention to treat cervical spine pathology. Although these were originally performed as single-level procedures, multilevel ACDF has been performed for patients with extensive degenerative disc disease. To date, there is a paucity of data regarding outcomes related to ACDFs of 3 or more levels. The purpose of this study was to compare surgical outcomes of 3- and 4-level ACDF procedures. The authors performed a retrospective chart review of patients who underwent 3- and 4-level ACDF at the University of Virginia Health System between January 2010 and December 2017. In patients meeting the inclusion/exclusion criteria, demographics, fusion rates, time to fusion, and reoperation rates were evaluated. Fusion was determined by < 1 mm of change in interspinous distance between individual fused vertebrae on lateral flexion/extension radiographs and lack of radiolucency between the grafts and vertebral bodies. Any procedure requiring a surgical revision was considered a failure. Sixty-six patients (47 with 3-level and 19 with 4-level ACDFs) met the inclusion/exclusion criteria of having at least one lateral flexion/extension radiograph series ≥ 12 months after surgery. Seventy percent of 3-level patients and 68% of 4-level patients had ≥ 24 months of follow-up. Ninety-four percent of 3-level patients and 100% of 4-level patients achieved radiographic fusion for at least 1 surgical level. Eighty-eight percent and 82% of 3- and 4-level patients achieved fusion at C3-4; 85% and 89% of 3- and 4-level patients achieved fusion at C4-5; 68% and 89% of 3- and 4-level patients achieved fusion at C5-6; 44% and 42% of 3- and 4-level patients achieved fusion at C6-7; and no patients achieved fusion at C7-T1. Time to fusion was not significantly different between levels. Revision was required in 6.4% of patients with 3-level and in 16% of patients with 4-level ACDF. The mean time to revision was 46.2 and 45.4 months for 3- and 4-level ACDF, respectively. The most common reason for revision was worsening of initial symptoms. The authors' experience with long-segment anterior cervical fusions shows their fusion rates exceeding most of the reported fusion rates for similar procedures in the literature, with rates similar to those reported for short-segment ACDFs. Three-level and 4-level ACDF procedures are viable options for cervical spine pathology, and the authors' analysis demonstrates an equivalent rate of fusion and time to fusion between 3- and 4-level surgeries.

Groundwater dynamics within a watershed in the discontinuous permafrost zone near Umiujaq (Nunavik, Canada)

Groundwater distribution and flow dynamics were studied in a small watershed located in the discontinuous permafrost zone near Umiujaq in Nunavik (Quebec), Canada, to assess the seasonal variations and perform a quantitative analysis of the water cycle in a subarctic watershed. Due to the complexity of the subsurface geology within the watershed, an integrated investigation was instrumental to provide a detailed understanding of the hydrogeological context as a basis for the water balance. Based on this water balance, for the two studied hydrological years of 2015 and 2016, the average values are 828 mm for precipitation, 337 mm for evapotranspiration, 46 mm for snow sublimation, 263 mm for runoff, 183 mm for groundwater exchange (losses with other aquifers outside the watershed), and 0 mm for change in water storage. Although these values likely have significant uncertainty and spatial variability, this water balance is shown to be plausible. It was also found that permafrost influences surface water and groundwater interaction, even if located in low-permeability sediments. It is expected that permafrost degradation will likely increase stream baseflow, especially in winter.

RTHP-22. EDEMA PROGRESSION DURING MRI-GUIDED GLIOBLASTOMA RADIOTHERAPY

Abstract PURPOSE Despite the common finding of pseudoprogression or true progression one month after primary chemoradiotherapy for glioblastoma, there are few studies evaluating brain MRI changes that occur during concurrent chemotherapy and radiotherapy (RT). With the first generation combination MRI-RT device, daily predominantly T2-weighted MRIs are obtained of glioblastoma during RT. We quantified how many patients had significant MRI detectable volumetric changes through the six week course of primary chemoradiotherapy. This is of particular importance since glioblastoma RT is only planned at the beginning of therapy and not commonly re-planned for changes during therapy. METHODS We retrospectively reviewed the daily set-up imaging of 8 patients at our institution who received RT for glioblastoma using the Cobalt-60 MRI-RT system. Patients received standard chemoradiation at 60 Gy in 30 fractions with temozolomide per EORTC22981/26981. We contoured the abnormality on the initial ViewRay setup scan and the set-up scan for fraction 30. After rigid fusion of the contours of the initial setup MRI and fraction 30 MRI, the volumes were compared. RESULTS Of the 8 patients, 3 patients (37.5%) demonstrated edema expansion greater than 5 mm. The maximum distances of T2-weighted abnormality volume growth for these patients were 1.0 cm, 1.5 cm, and 4.1 cm. These findings were correlated with the post-treatment diagnostic MRIs at 3–4 weeks which demonstrated similar FLAIR abnormalities and expansion in T1 with gadolinium contrast volumes within these areas of the radiotherapy fields (pseudoprogression vs. true progression). CONCLUSION Review of MRIs obtained by daily MRI-RT for glioblastoma indicates that 3 of 8 patients had over 5 mm of change in T2-weighted dimensions from beginning to end of radiotherapy. Groups using limited CTV margins for treatment planning should be aware that MRI volumes could significantly increase during radiotherapy.

Evaluating the Utility of Follow-up Radiographs for Isolated Radial Head Fractures Undergoing Initial Nonoperative Treatment.

To evaluate the utility of follow-up radiographs in patients with isolated partial articular radial head fractures (OTA/AO 2R1B1 or 2R1B3). Retrospective cohort study. Academic Level 1 Trauma Center. Adult patients (≥18 years) with isolated partial articular radial head fractures indicated for initial nonoperative treatment. Analysis of elbow radiographs at initial presentation and at postinjury follow-up of 3-8 weeks. Articular gap and step-off. Radiographic articular displacement between initial and follow-up radiographs. For 72 included patients, initial radiographs were obtained on average 2.6 days after injury and follow-up radiographs 33.7 days thereafter. Equivalence tests evaluating gap and step-off thresholds of <1 mm were both significant, indicating that the cohort displaced <1 mm for both parameters between initial and follow-up radiographs. No patients proceeded to surgical treatment following the repeat radiographs. These fractures do not displace in the early postinjury period, as defined as a <1 mm of change in both intra-articular gap and step-off, as compared to initial radiographs. Routine follow-up radiographs for these injuries is a source of cost, but with limited utility in detecting interval displacement or leading to a change in management. Selective use of radiographs to evaluate specific clinical concerns may lead to cost savings. Diagnostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Significance of Early Postoperative Eyelid Position on Late Postoperative Result in Mueller's Muscle Conjunctival Resection and External Levator Advancement Surgery.

The purpose of this study was to determine whether advancement of the levator aponeurosis in external levator resection surgery or Mueller's muscle and conjunctiva in Mueller's muscle conjunctival resection (MMCR) surgery has a differential effect on variation in eyelid position during the postoperative period. In this retrospective observational cohort study, 2 groups of patients were defined. The first underwent MMCR surgery without tarsectomy by surgeon 1. The second underwent external levator resection without dissection posterior to the levator aponeurosis by surgeon 2. Marginal reflex distance (MRD1) was calculated based on digital photographs at baseline, 1 week postoperatively and at 3-month follow up. The primary outcome measure was change in MRD1 over time. The secondary outcome was defined as the proportion of patients with minimal early postoperative change (change of MRD1 less than 0.5 mm at 1 week postoperatively). Repeated measures analysis of variance, t test, and chi-square analyses were performed. Of the 114 eyes in the sample, there were 68 in the MMCR group and 46 in the external levator resection group. A significant interaction between group and time was noted (p < 0.05), indicating change in MRD1 over time was different between the groups. Bonferroni corrected multiple comparisons yielded significant differences between each time point for MMCR surgery (p < 0.01). No difference in MRD1 was noted for the external levator resection group from the early to late postoperative visit. Comparing each time point across groups revealed significantly lower MRD1 for the MMCR group at the early postoperative visit (p < 0.01). Preoperative and late postoperative MRD1 did not significantly differ between the groups. Regarding the secondary outcome, patients undergoing MMCR surgery were 3.7× as likely to demonstrate <0.5 mm of change in MRD1 at week 1 (p < 0.05). When considering the 39.7% (n = 27) MMCR patients in this category, 59.3% (n = 16) went on to show an MRD1 increase >1 mm from the early postoperative to the late postoperative time points. Both external levator resection and MMCR can effectively elevate the eyelid in cases of primary involutional ptosis, and have similar late postoperative results. The authors found that MMCR cases undergo greater change between the early and late postoperative period, suggesting the process of eyelid elevation after MMCR may be dynamic, involving postoperative physiologic modification.

Quantitative evaluation of the occupant kinematic response of the THUMS 50th-percentile male model relative to PMHS laboratory rollover tests

ABSTRACTObjective: The objective of the current study was to evaluate the whole-body kinematic response of the Total Human Model for Safety (THUMS) occupant model in controlled laboratory rollover tests by comparing the model response to postmortem human surrogate (PMHS) kinematic response targets published in 2014.Methods: A computational model of the parametric vehicle buck environment was developed and the AM50 THUMS occupant model (Ver 4.01) was subjected to a pure dynamic roll at 360°/s in trailing-side front-row seating position.A baseline configuration was defined by a baseline posture representing the average of all PMHS postures, with a friction coefficient of 0.4 for the belt and 0.6 for the seat.To encompass challenges in controlling boundary conditions from the PMHS tests and ensure the robustness of the model evaluation, a total of 12 simulations were performed to investigate the following:1. The effect of initial posture by adding 3 additional postures representing PMHS extremes.2. The effect of belt tension by varying tension from the nominal vehicle retractor belt tension of 5 N to the 35 N belt tension used in the PMHS tests.3. The effect of friction between the environment (belt, seat) and THUMS.Trajectories (head, T1, T4, T10, L1, and sacrum), spinal segment rotations (head-to-T1, T1-to-T4, T4-to-T10, T10-to-L1, and L1-to-sacrum) relative to the rollover buck and spinal segment elongation/compression calculated from the simulations were compared to PMHS corridors using a correlation method (CORA).Results: THUMS baseline response showed lower correlation (overall CORA score = 0.63) with the PMHS response in rollover compared to other crash modes. THUMS and PMHS demonstrated similar kinematic responses in the longitudinal axis and vertical axis but significantly different lateral excursion relative to the seat. In addition, no spinal elongation was observed for THUMS compared to the PMHS.The posture, pretension, and belt frictions were found to alter model kinematics, especially on THUMS lateral axis motion. The posture was judged to be the most sensitive parameter evaluated because a change of 30 mm in the lateral axis results in up to an 80 mm of change in observed displacement.Conclusions: Though the model response in the lateral axis is significantly different than that of the PMHS, it is unclear whether this difference is the result of extrinsic factors (posture, pretension, and friction), where exact values in experiment are unknown or by model intrinsic factors (e.g., spine stiffness). These differences in occupant kinematics could potentially subject the PMHS and THUMS to very different loading conditions under roof impact in rollover crashes: different occupant posture and different roof impact location. Therefore, different injury mechanisms and severity might be predicted by the current model relative to the PMHS. Consequently, though the information provided in the current study could be useful for improving model biofidelity for rollover crashes, additional studies are required to properly solve this issue.

Accuracy of Component Placement in Robotic-Assisted Total Hip Arthroplasty.

Robotic-assisted total hip arthroplasty (THA) is a recent platform introduced to decrease the risk of malpositioned components. The goals of this study were to determine whether intraoperative data on robotic-assisted THA acetabular component position accurately predict postoperative radiographic acetabular component position and to determine whether intraoperative data on robotic-assisted THA leg length and offset accurately predict postoperative radiographic leg length and offset data. In 146 patients, pre- and postoperative radiographs and intraoperative component measurements were reported for acetabular inclination, anteversion, leg length change, and offset change. Component position obtained by the robotic system and radiographic data were compared with subgroup analysis for the posterior and direct anterior approaches. The average difference between groups was 3.3°±3.1° for inclination, 2.9°±2.3° for anteversion, 3.0±2.3 mm for leg length change, and 4.0±3.1 mm for change in global offset. Correlation between the robotic system and postoperative radiographs was within 10° for 95.9% of cases for inclination and 99.3% for anteversion. Posterior approach correlation was within 10° for 97.1% of cases for inclination and 100% for anteversion. Anterior approach correlation was within 10° for 92.7% of cases for inclination and 97.6% for anteversion. Intraoperative data on component position obtained from the robotic system compared well with radiographic data on component position. Surgeons must remain vigilant to ensure outliers related to robotic system malfunction do not occur. [Orthopedics. 2016; 39(3):193-199.].

Incidence of periodontal attachment loss over 5 years among older South Australians.

This study described the 5-year incidence of periodontal attachment loss (ALOSS) among older Australians. Clinical examination data were obtained at baseline and 5 years from participants in a cohort study of South Australians aged 60+. Periodontal measurements (gingival recession, GR; probing depth, PD) were made for each tooth at 3 sites. An incident case of ALOSS was identified as an individual having 2+ sites with 3+ mm ALOSS. Some 342 (42.7%) of the 801 individuals examined at baseline were re-examined after 5 years, contributing longitudinal data from a total of 15,522 sites (6102 in the maxilla and 9420 in the mandible). Most sites showed no change in either GR or PD. Using a threshold of 3+ mm for change, ALOSS occurred at 2.3% of mesiobuccal sites, 2.5% of buccal sites, and 3.4% of distolingual sites. Distolingual sites on molars showed the highest progression rates. The major component of ALOSS was increased GR. Overall, only 10.1% of the observed ALOSS was contributed by increases in PD. Nearly two-thirds of the sites that experienced ALOSS had <3 mm of ALOSS at baseline. The weighted 5-year incidence estimate for ALOSS was 43.2% (N=145), and was higher among diabetics or those who had lost 1+ teeth since baseline. Smoking was not a significant predictor. The rates and patterns of ALOSS among older South Australians are largely similar to those recently reported for North Carolinians. Most ALOSS in older people manifests as increases in GR, rather than PD. Diabetics should be targeted for intensive primary and secondary prevention of periodontal disease.

Penetration depth as a DInSAR observable and proxy for soil moisture

We use prior theory and experimental results to construct a quantitative relationship between soil moisture and the penetration depth of synthetic aperture radar (SAR) microwaves at L-, C-, and X-bands. This relationship is nonlinear and indicates that a change of 5% volumetric water content (VWC) can cause between 1 and 50 mm of change in C-band penetration depth depending on initial VWC. Because these depths are within the range of differential interferogram SAR (DInSAR) measurement capability, penetration depth may be a viable proxy for measuring soil moisture. DInSAR is unlikely to detect a measurable change in penetration depth above 30% VWC, though certain clay rich soils may continue to cause surface deformation above that level. The possibility of using clay swelling as a proxy for soil moisture was found to be less feasible than penetration depth. Soil moisture may also be a significant, and previously unrecognized, source of noise in the measurement of subtle deformation signals or the creation of digital elevation models using repeat-pass DInSAR.

Influence of Bicortical or Monocortical Anchorage on Maxillary Implant Stability: A 15-Year Retrospective Study of Brånemark System Implants

Influence of Bicortical or Monocortical Anchorage on Maxillary Implant Stability: A 15-Year Retrospective Study of Brånemark System Implants C.J. Ivanoff, K. Gröndahl, C. Berström, et al., Int J Oral Maxillofac Implants. 2000;15:103–110 In the literature, there is considerable debate over the benefits of bicortical stabilization of implants. The purpose of this retrospective study was to evaluate, over a 15-year follow-up period, implant survival and marginal bone loss in the maxilla as a function of either monocortical (MC) or bicortical (BC) implant stabilization. The following selection criteria were used to develop an investigative sample drawn from a patient population treated from 1977 to 1983: edentulous patients were provided with 10-mm long Brånemark implants independent of bone quality. Any patients who were treated with grafts or implants of different length or design were excluded. Based on these selection criteria, a patient population consisting of 20 women and 17 men, having a mean age of 50 years (range 31 to 73 years), was evaluated. The study encompassed 37 maxillary arches giving a total 207 implants for analysis. Radiographic verification via a panoramic image of either monocortical or bicortical stabilization was accomplished by ascertaining if the apical portion of the implant either engaged the anterior or inferior border of the maxillary sinus or floor of the nasal cavity. Following this procedure, three examiners classified 110 implants as MC and 97 as BC. An equal distribution amongst the patient group was found with respect to the ratio of MC or BC implants per patient. Implant survival was assessed by patient records. Marginal bone levels were assessed using intraoral radiographs in relation to a fixed point on the implant. Measurements were made under magnification to the nearest 0.1 mm. Of the original 37 patients, 30 were available after 5 years, 23 after 10 years, and 16 after 15 years. In terms of the drop-out rate’s effect on results, 35% of the MC implants and 45% of the BC implants were lost to follow-up by year 15. Of the 207 implants, a total of 18 (8.7%) failed during the follow-up period. In regards to status of MC or BC stabilization, the survival rates were 96.2% and 84.8%, respectively. The MC group showed four (3.6%) failures out of 110 implants, all four of which fractured. The BC group showed 14 (14.4%) failures out of 97 implants. Of the 14 failures, 11 of the failures were due to fracture (three times higher than MC group), whereas the remaining three failed (all in one patient) due to a loss of integration. Sixteen of the total 18 failures occurred in three patients, who had a high ratio of BC implants. Other variables that may influence implant survival such as smoking, opposing occlusion, cantilever length, and parafunction were not evaluated. As for marginal bone loss, less than 1.0 mm of change was observed over the 15-year period regardless of type of implant anchorage. This study found a four times higher failure rate amongst BC implants versus those with MC stabilization, whereas no difference in marginal bone loss could be observed between the two groups. Although the results of this study should be interpreted with caution, the fact that this paper assesses the concept of either monocortical or bicortical stabilization for implants of equal length is unique.

Which angiographic variable best describes functional status 6 months after successful single-vessel coronary balloon angioplasty?

Objectives. The aim of this study was to determine which quantitative angiographic variable best describes functional status 6 months after coronary balloon angioptasty.Background. Several angiographic restenosis criteria have been developed. These can be divided into those that describe the changein lesion severity and those that merely describe lesion severity at follow-up angiography. The functional significance of these criteria is unknown.Methods. We studied 350 patients with single-vessel coronary artery disease who underwent a single-site balloon dilation. Sensitivity and specificity curves were constructed for the prediction of anginal status and exercise electrocardiography of four quantitative angiographic variables that describe restenosis. The point of highest diagnostic accuracy for the variables was determined at the intersection of the sensitivity and specificity curves. Results of exercise electrocardiography were considered indicative for ischemia 6 months after angioplasty if horizontal or downsloping ST segment depression ≥1 mm occurred.Results. The points of biggest diagsostic accuracy of the angiographic variables were similar for both anginal status and exercise electrocardiegraphy: 1.45 and 1.46 mm for the minimal lumen diameter measurements, 45.5% and 46.5% for the percent dinneter stenosis measurements at follow-up, -0.30 and -0.32 mm for change in minimal lumen diameter and -10% and -10% for the change in percent diameter stenosis at follow-up.Conclusions. Angiographic variables reflecting a change in lesion severity at follow-up angiography were only slightly less accurate than variables that describe lesion severity at follow-up. The large study group and the fact that the same optimal values for diagnostic accuracy of the various quantitative angiographic variables were obtained for the prediction of two different markers of ischemia suggests that these values reflect the lesion severity or increase in lesion severity in major epicardial vessels at which coronary flow reserve is unable to meet myocardial demands.

Recognition of profile change after simulated orthognathic surgery.

Fifty-one oral and maxillofacial surgeons, 52 orthodontists, 51 orthognathic surgery patients, and 100 lay persons evaluated life-size lateral photographs of two male and two female subjects that had been altered to simulate varying amounts of surgical correction of mandibular retrognathism and prognathism. A horizontal change at pogonion of less than 4 mm was generally not recognized by more than half of the lay groups. The dental groups were more accurate, but even they did not achieve better than 80% recognition until 6 mm of change. Both the dental and lay groups recognized change more easily in the female and the prognathic subjects. When asked which feature appeared changed, dentists generally indicated the chin and lay groups the lips.

Identifying Turgor Responses of Water‐Stressed Cotton to Rapid Changes in Net Radiation Using Spectral Analysis1

The kinetics of stem shrinkage and swelling in response to changes in the radiation loading of field‐grown cotton (Gossyplum hirsutum L.) plants were examined by time series spectral analysis. This technique involves determination in the frequency domain of the relationship between two time series events. The type and degree of relationship a.re assessed by computing the squared coherency, phase, and gain spectra relating events in the measured net radiation and stem diameter data sets. The squared coherency spectrum shows the statistical strength of the relationship between events in the two time series, while the grain spectrum indicates the amount of response, or the mm of change in stem diam. eter resulting from a unit change in radiation intensity at each frequency. The phase spectra show the relative positions between maximum points in the two time seriesPlants growing under conditions of water stress respond to changes in radiation much more rapidly than those growing on well‐watered, deep soils. Although low frequency (slow) shrinkage response may be caused factors affecting both evapotranspiration from the leaves and root water uptake, high frequency (rapid) shrinkage or swelling responses are probably controlled exclusively by alterations in the rate of water loss because of the water storage capacity of the plant itself.