Joint-Preserving Osteotomy of the Lateral Tibial Plafond for Posttraumatic Osteonecrosis: A Prospective Cohort Study.

BACKGROUND: Posttraumatic osteonecrosis (ON) of the lateral distal tibia is a rare but severe complication of malleolar fractures. Treatment options include ankle fusion, arthroplasty, osteotomy, and drilling but clinical data on outcomes are limited to single case reports. The aim of this study was to prospectively evaluate the outcome following joint-preserving reconstruction. METHODS: Over a 10-year period, 10 patients (8 females and 2 males, average age 36 years; range, 27-68 years) with posttraumatic ON were treated with intra-articular osteotomy of the distal tibia and bone grafting. All patients initially sustained a closed pronation injury, 7 with initial tibiotalar subluxation. Chronic syndesmotic instability following initial treatment was present in 4 patients and 5 were smokers. All patients were followed for a median of 68 (range, 12-103) months, 7 returned in person for clinical and radiographic follow-up. RESULTS: No immediate postoperative complications were seen. Secondary ankle fusion was necessary in 1 case (10%) because of progressive osteoarthritis. At the time of follow-up, anterior ankle arthritis leading to impingement and requiring cheilectomy was noted in 4 cases, partial graft necrosis, and secondary syndesmotic instability requiring revision surgery was seen in 1 case each. Compared with the preoperative values, significant improvement in the Olerud-Molander Ankle Score (P = .012), EuroQuol-5 Score (P = .008), and Foot Function Index (FFI-D pain, P = .028; FFI-D restriction, P = .038) was seen. Average range of motion at the ankle was 45 degrees. CONCLUSION: In our limited series of patients with posttraumatic ON of the lateral distal tibia, we found that joint-preserving reconstruction using an intra-articular distal tibial osteotomy with autologous bone grafting usually provided significant functional improvement and pain relief. In our cohort secondary fusions by a median 5.5-year follow-up were rare, but secondary, joint-sparing surgeries were common. LEVEL OF EVIDENCE: Level III, prospective study.

Use of CT and MR imaging in radiation therapy planning of imaging-diagnosed canine intracranial meningioma achieves better tumor coverage than CT alone.

The aim of this retrospective, secondary analysis study was to quantify the dosimetric impact of the lack of interobserver agreement on gross tumor volume (GTV) delineation for canine meningioma. This study used a previously reported population of 13 dogs with GTVs contoured on CT alone and on registered CT-MR by 18 radiation oncologists. The "true" GTV was generated for each dog using a simultaneous truth and performance-level estimation algorithm, and "true" brain was defined as the whole brain minus true GTV. Treatment plans were generated for each dog and observer combination, using criteria applied to the observer's GTV and brain contours. Plans were then categorized as a pass (met all planning criteria for true GTV and true brain) or fail. A mixed-effects linear regression was performed to examine differences in metrics between CT and CT-MR plans and mixed-effects logistic regression was performed to examine differences in percentages of pass/fail between CT and CT-MRI plans. The mean percent coverage of true GTV by prescribed dose was higher for CT-MR plans than for CT plans (mean difference 5.9%; 95% CI, 3.7-8.0; P < 0.001). There was no difference in the mean volume of true brain receiving ≥24 Gy and in maximum true brain dose between CT plans and CT-MR plans (P ≥ 0.198). CT-MR plans were significantly more likely to pass the criteria for true GTV and true brain than CT plans (OR 1.75; 95% CI, 1.02-3.01; P = 0.044). This study demonstrated significant dosimetric impact when GTV contouring was performed on CT alone compared with CT-MR.

Contouring in the optic plane improves the accuracy of computed tomography-based segmentation of the optic pathway.

Canine optic pathway structures are often contoured on CT images, despite the difficulty of visualizing the optic pathway with CT using standard planes. The purpose of this prospective, analytical, diagnostic accuracy study was to examine the accuracy of optic pathway contouring by veterinary radiation oncologists (ROs) before and after training on optic plane contouring. Optic pathway contours used as the gold standard for comparison were created based on expert consensus from registered CT and MRI for eight dogs. Twenty-one ROs contoured the optic pathway on CT using their preferred method, and again following atlas and video training demonstrating contouring on the optic plane. The Dice similarity coefficient (DSC) was used to assess contour accuracy. A multilevel mixed model with random effects to account for repeated measures was used to examine DSC differences. The median DSC (5th and 95th percentile) before and after training was 0.31 (0.06, 0.48) and 0.41 (0.18, 0.53), respectively. The mean DSC was significantly higher after training compared with before training (mean difference = 0.10; 95% CI, 0.08-0.12; P < 0.001) across all observers and patients. DSC values were comparable to those reported (0.4-0.5) for segmentation of the optic chiasm and nerves in human patients. Contour accuracy improved after training but remained low, potentially due to the small optic pathway volumes. When registered CT-MRI images are not available, our study supports routine addition of an optic plane with specific window settings to improve segmentation accuracy in mesaticephalic dogs ≥11 kg.

Species distributions and the recognition of risk in restoration planning: A case study of salmonid fishes.

One of the risks faced by habitat restoration practitioners is whether habitats included in restoration planning will be used by the target species or, conversely, whether habitats excluded from restoration planning would have benefited the target species. With the goal of providing a quantitative decision-making approach that represented varying levels of risk tolerance, we used multiple probability decision thresholds (PDT) to predict the range of occurrence for three anadromous fishes (Oncorhynchus spp.) in a watershed in southwestern Washington, USA. For each species, we compared the predicted range of occurrence to the distribution used for restoration planning and quantified the amount of habitat blocked by anthropogenic barriers. Coho salmon (O. kisutch) had the broadest predicted range of occurrence (3061.6-6357.9 km; 0.75-0.25 PDT), followed by steelhead trout (O. mykiss; 1828.8-2836.8 km) and chum salmon (O. keta; 1373.9-1629.1 km). For each species, the predicted range of occurrence was similar or greater than the distribution used for restoration planning, suggesting that the current plan may exclude habitats that would benefit each species. Coho salmon had the greatest percentage of habitat blocked by anthropogenic barriers, followed by steelhead trout and chum salmon, respectively. Modeling species distributions at multiple risk-tolerance scenarios acknowledges uncertainty in restoration planning and allows practitioners to weigh the ecological benefits and budgetary constraints when considering locations for restoration. To effectively communicate restoration science to support practitioners in decision-making, we developed an R Shiny application online user interface available at: https://shiny.wdfw-fish.us/ChehalisRiverBasinSalmonidRangeOfOccurence/.

Ecotoxicology of mercury in burbot (Lota lota) from interior Alaska and insights towards human health.

Fish consumption has many health benefits, but exposure to contaminants, such as mercury (Hg), in fish tissue can be detrimental to human health. The Tanana River drainage, Alaska, USA supports the largest recreational harvest of burbot (Lota lota) in the state, yet information to evaluate the potential risks of consumption by humans is lacking. To narrow this knowledge gap, we sought to (i) quantify the concentrations of total Hg ([THg]) in burbot muscle and liver tissue and the ratio between the two tissues, (ii) assess the effect of age, length, and sex on [THg] in muscle and liver tissue, (iii) evaluate if [THg] in muscle tissue varied based on trophic information, and (iv) compare observed [THg] to consumption guidelines and statewide baseline data. The mean [THg] was 268.2 ng/g ww for muscle tissue and 62.3 ng/g ww for liver tissue. Both muscle [THg] and liver [THg] values were positively associated with fish length. Trophic information (δ15N and δ13C) was not significantly related to measured [THg] in burbot muscle, which is inconsistent with typical patterns of biomagnification observed in other fishes. All burbot sampled were within the established categories for consumption recommendations determined by the State of Alaska for women of childbearing age and children. Our results provide the necessary first step towards informed risk assessment of burbot consumption in the Tanana drainage and offer parallels to fisheries and consumers throughout the subarctic and Arctic region.

Penetrating arterial trauma to the limbs: outcome of a modified protocol.

BACKGROUND: Penetrating arterial injuries to the limbs are common injuries in high volume trauma centers. Their overall surgical results reported in the literature are satisfactory - apart of those of the popliteal artery that still may lead to a significant incidence in amputations. With the present study we assessed our outcome with penetrating arterial injuries to the limb as to see if the direct involvement of vascular surgeons in the management of popliteal artery injuries leads to an improved (lowered) amputation rate. Results were benchmarked with our published results from previous years. METHODS: All patients sustaining penetrating arterial injuries to the limbs admitted to the Chris Hani Baragwanath Academic Hospital during an 18- month period ending in September 2011 were included in this study. Axillary, brachial and femoral artery injuries were operated on by the trauma surgeons as in the past. All popliteal artery injuries were operated on by the vascular surgeons (new). RESULTS: There were a total of 113 patients with 116 injuries, as some patients had multiple vascular injuries: 10 axillary, 47 brachial, 34 femoral and 25 popliteal artery injuries. Outcome of axillary, brachial and femoral artery injury repair were excellent and not significantly different from our previous reported experience. Injury to the popliteal artery showed a diminished re-exploration rate from 34% down to 10% (p = 0,049) and a decrease of amputation rate from 16% to 11% which was statistically not significant (p = 0,8). CONCLUSION: Penetrating arterial trauma to the axillary, brachial and femoral artery is followed by excellent results when operated by trauma surgeons. In the case of popliteal artery injury operated by the vascular surgeons, the results of this study do not show any statistically significant difference related to amputation rate from our previous reported studies when operated by trauma surgeons. Taking into consideration the diminished re-exploration rate and a tendency to a lower amputation rate, we feel that there is possible tendency of better outcome if operated by vascular surgeons. Multicenter studies with large number of enrolled patients will be required to prove the validity of this suggestion.

Rapid Assembly of Oligosaccharides: Total Synthesis of a Glycosylphosphatidylinositol Anchor of Trypanosoma brucei.

Six building blocks, six reaction steps: The recently developed innovative methodology facilitated the convergent synthesis of the complex oligosaccharide core 1 (shown here with protecting groups) for the total synthesis of a glycosylphosphatidylinositol (GPI) anchor. The key factors are the tuning of the reactivity of the building blocks by using 1,2-diacetal protecting groups and the desymmetrization of glycerol and myo-inositol with a chiral bis(dihydropyran).