Loss Of Correction Research Articles

Outcomes for standalone anterolateral corpectomy for thoracolumbar burst fractures.

There is a paucity of data available on the context preceding anterior fusion failure or the need for a posterior fusion, the timing of the second operation, or any correlation between the different instrumentation and failure rates. A retrospective chart review was performed of 131 identified patients who underwent anterolateral corpectomy and fusion for a thoracolumbar burst fracture from 2000 to 2012 in a single institution. 96 patients had clinical and radiographic follow up of greater than two months. Mean kyphosis correction from preoperative (14.1°) to postoperative kyphosis (6.3°) was 7.7° and 37% had loss of kyphotic correction at follow-up. In a univariate analysis, use of a bone strut graft (OR 3.2, p = 0.01), point-loaded graft position (OR4.9, p = 0.005), end plate damage/subsidence (OR 6.7, p < 0.0001), and graft to endplate width ratio of ≤ 45% on AP x-ray (OR 3.0, p = 0.02) were associated with loss of kyphotic correction. 41% demonstrated scoliosis of ≥ 5° at follow-up. Graft location towards the left of midline (OR 8.6, p < 0.0001), point-loaded graft position (OR 3.8, p = 0.01), and end plate damage/subsidence (OR 5.5, p = 0.0001) were also associated with scoliosis at the time of final follow-up. Five patients required posterior fusion and fifteen patients continued to have daily pain, only one of which was determined to be related to kyphosis. Use of a bone strut graft versus expandable cage, graft location, graft position, presence of early or late subsidence and width of the graft may be associated with loss of kyphotic correction and scoliosis.

A semi‐supervised segmentation network fusing pseudo‐label with multi‐level feature consistency correction for hard exudates

AbstractTimely detection of hard exudates in fundus images can effectively avoid the severity of the disease, but the labelling of small and numerous lesion areas requires a lot of labour costs. This paper proposes a semi‐supervised segmentation network, which integrates pseudo‐labels and multi‐level features consistency correction. It achieves accurate segmentation of hard exudates by making full use of a small amount of labelled data and a large amount of unlabelled data. The network effectively extracts features from the unlabelled data through knowledge transfer of the teacher‐student model, and incorporates a Transformer network for auxiliary training to promote the quality of transfer. In addition, three unsupervised losses are introduced to improve the performance: the perturbation loss improves the robustness of the model to noise by adding different noises to the same input; the multi‐level feature consistency correction loss ensures the consistency of features of the student model at different scales; and the pseudo‐labelling cross‐supervision loss utilizes the generated pseudo‐labels for supervision between CNN and Transformer. By comparing the segmentation results with different proportion of the labelled data, it has better segmentation performance compared to other methods. The proposed methods can totally increase dice by 16.56% and mean intersection over union (MIoU) by 25.11%.

Clinical and radiological comparisons between oblique lumbar interbody fusion combined with percutaneous pedicle screw fixation and transforaminal lumbar interbody fusion for adult isthmic spondylolisthesis: a 2-year follow-up study

Adult isthmic spondylolisthesis(AIS) results in the anterior translation of the vertebral body with neural encroachment. Although oblique lumbar interbody fusion(OLIF) is minimally invasive technique that use a retroperitoneal plane to achieve indirect decompression compared to transforaminal lumbar interbody fusion(TLIF), research on OLIF for AIS remains limited. Therefore, we aimed to compare the clinical and radiological outcomes of these two surgical techniques for AIS. We analyzed the details of 62patients with AIS who were treated with either OLIF(n=26) or TLIF(n=36) between 2019 and 2022, with a minimum 2-year follow-up. The two surgical techniques were compared in terms of perioperative surgical, radiological, and clinical outcomes. The correlation between the severity of foraminal stenosis and clinical outcomes was evaluated. The OLIF group experienced significantly less blood loss, shorter operative times, and shorter hospital stay than the TLIF group. Radiological assessments showed no significant preoperative differences in disc height or slippage ratios, but postoperative slippage correction was significantly greater in the OLIF group than in the TLIF group(13.5±8.0 versus 5.0±8.9; p<0.001). The clinical outcome improvement ratios did not differ significantly between the two groups. The correlation between preoperative severity of foraminal stenosis and clinical outcomes in the OLIF group was not significant. OLIF is more advantageous than TLIF in terms of blood loss, operative time, hospital stay and anterolisthesis correction. In addition, good clinical outcomes were obtained with indirect decompression alone, regardless of the severity of foraminal stenosis. Therefore, OLIF is a good surgical option for the treatment of AIS.

Bone density as a risk of early loss of correction after percutaneous posterior spinal fixation for traumatic thoracolumbar fracture: a study on the usefulness of Hounsfield unit values on computed tomography scan.

Vertebral Hounsfield unit values on computed tomography scan (CT values) have been found to be correlated with bone density measured using dual-energy X-ray absorptiometry. We hypothesized that low preoperative CT values are risk factors for early loss of correction after percutaneous posterior spinal fixation (PPSF). This study aimed to evaluate the usefulness of measuring preoperative CT values. In total, 104 patients underwent PPSF due to traumatic thoracolumbar fracture. Among them, 53 with a range of fixation that was within two vertebrae above and below the fractured vertebra were selected. CT values were measured preoperatively from the most cephalad vertebrae on the fixed vertebrae. Vertebral wedge angle (VWA) and local kyphosis angle (LKA) were measured before and after surgery. participants were classified into progression (P) and nonprogression (NP) groups. The P group comprised patients with LKA progressing > 10° from the immediate postoperative period to 3months postoperatively. Meanwhile, the NP group included patients without progression. Eight (15.1%) patients were included in the P group. The vertebral CT values were 102.2 ± 36.7 in the P group and 162.4 ± 59.7 in the NP group (p < 0.01). The pedicle CT values were 114.4 ± 45.9 in the P group and 170.8 ± 72.3 in the NP group (p < 0.05). At 2weeks postoperatively, VWA and LKA of the P group progressed to 9.8° ± 7.0° and 10.9° ± 7.6°, respectively. CT values can predict progressive loss of correction after PPSF.

Debridement and Bone Graft Fusion via the Lateral Extracavitary Approach Combined with Lateral and Posterior Screw-rod Fixation in the Treatment of Thoracic Spinal Tuberculosis: A Retrospective Study of 38 Cases

ObjectivesThoracic spinal tuberculosis (TB) is still common, and surgical treatment can rapidly relieve pain, correct deformity, reduce bone loss and prevent further damage to neurological function. We have practiced an efficient and safe surgical method. MethodsFrom January 2013 to April 2021, 38 patients with thoracic spinal TB were included in our study. Debridement and bone grafting were performed via the lateral extracavitary approach, combined with two different fixation methods. Data from these cases were analyzed retrospectively. ResultsFor all cases, the C-reactive protein (CRP) level and erythrocyte sedimentation rate (ESR) of all the patients decreased to normal levels at the last follow-up. The average visual analog scale (VAS) score was 7.5±1.6 preoperatively and 0.6±0.8 at the last follow-up, showing a significant reduction. The average angle of kyphosis correction was 6.3±4.7°, and the loss of correction was 1.4±1.6°. Neurological function was significantly improved in all cases according to the American Spinal Injury Association (ASIA) classification. Solid fusion was observed in all cases at the last follow-up. ConclusionsDebridement and bone graft fusion via the lateral extracavitary approach combined with two fixation methods can be very effective in the treatment of thoracic spinal TB.

Spine to pelvis “T-Construct” using magnetic controlled growing rods in non-walkers neuromuscular early-onset scoliosis: a preliminary study

BackgroundsMagnetic controlled growing rods (MCGRs) have been proven to be effective in controlling early onset neuromuscular scoliosis but no study has evaluated the combination with a sacro-bi-iliac construct. The aim of our study is to report surgical management of early onset non-walkers neuromuscular scoliosis correction using MCGRs associated with a sacro-bi-iliac “T-construct” and its mid-term outcomes. Our hypothesis was that this set-up provided well correction of the pelvic obliquity and that this correction was maintained over time. MethodsA retrospective single-center study was conducted including all consecutive neuromuscular early onset scoliosis who underwent spinopelvic fixation using “T-construct” with two MCGRS. Four millimeters lengthening was performed every 4 months during outpatient clinics sessions. All children had a low-dose biplanar stereoradiography in EOS-Chair at pre/postoperative phase, each outpatient clinic appointment and last follow-up. ResultsEighteen patients were included and 17 analyzed at the last follow-up. The mean age at surgery was 9.5 (range from 5 to 12 years), the mean follow-up was 4,7 years (range from 2.5 to 6.6 years) and 8 patients had a Risser stage above four. The global complication rate was 35% (N = 6/17 patients) including three medical and three mechanical complications related to “T-construct”, while the reoperation rate was 18% (N = 2 patients for wound debridement and one for iterative pelvic fixation). Cobb angle and pelvic obliquity were significantly improved by surgery (mean correction was 33.2 ° (55%) and 11 ° (77%) respectively; p < 0.001). At the last follow-up, we noted a loss of frontal Cobb angle correction (p < 0.01) whereas we did not observe any significant loss of pelvic obliquity (p > 0.9). ConclusionsAlthough the global complication rate was 35% (half of which are mechanical complications), the treatment combining pelvic T-construct and MCGRs provides satisfactory correction of pelvic obliquity correction, good maintenance in the medium term and may be a procedure to consider for the surgical treatment of early onset neuromuscular scoliosis. Level of evidenceIV; Retrospective cohort prognostic study

The One-Dimensional Flow Pressure Loss Correction Model Based on the Particle Flow through Concrete Bend

The rheological behavior of concrete pumping in the bend section is complex. The existing conversion calculation for pumping pressure loss based on the straight pipe section often fails to meet engineering precision requirements. This paper develops a pressure loss correction model for a concrete pumping bend section based on a new one-dimensional flow model for the straight pipe section simulation of particle flow; the study analyzes the impact of parameters such as elbow shape and pumping flow rate on pressure loss. An equivalent conversion relationship between the bend section and the straight section is established. The comparison with the measured pressure values from the project shows that the relative error between the pressure loss values calculated by the correction model and the actual measurements is 15.8%.

Rigid iatrogenic hallux varus: a decades’ worth experience with arthrodesis of the metatarsophalangeal joint

PurposeArthrodesis of the first ray metatarsophalangeal joint (MPJ) is the gold standard in iatrogenic hallux varus (IHV) in the presence of stiffness and osteoarthritis. The purpose of this study is to collect clinical and radiographic results and complications of MPJ arthrodesis in rigid iatrogenic HV.MethodsA retrospective evaluation of rigid iatrogenic HV undergoing arthrodesis with a minimum follow-up (FU) of two years was performed. The clinical parameters assessed were visual analog scale (VAS), the AOFAS Hallux Metatarsophalangeal-Interphalangeal Scale score and the satisfaction scale. The radiological parameters evaluated the first to second metatarsal angle (IMA) and the angle of hallux valgus (HVA). Complications were also analysed.ResultA total of 18 patients (19 procedures) with a mean FU of 5.5 ± 2.5 years were included. The mean VAS improved from 7.3 ± 1.6 to 1.3 ± 1.2 (p < 0.05) at the last FU. Similarly, the AOFAS Hallux Metatarsophalangeal-Interphalangeal scale score significantly improved to 82 ± 9.2 (p < 0.05). Radiological evaluation demonstrated a 1–2 IMA improvement from 4.4 ± 2.2° preoperatively to 8.9 ± 2.4° at 3 months post-operatively. Similarly, there was a significant (p < 0.05) improvement of the HVA from − 22.7 ± 4.1° to 13.1 ± 4.1° at three months post-operative (p < 0.05). No signification loss of correction was noted at the last follow-up (p > 0.05). In one case, a delayed fusion at the arthrodesis site required surgical revision to promote fusion. No patient experienced pain with stress from the first MTP joint arthrodesis site or identified the arthrodesis site as a source of pain. No patient required implant removal. Re-operation and revision rates were 5.3%. The overall complications rate was 15.8%.ConclusionsMPJ fusion effectively corrects Iatrogenic Hallux Varus in cases of rigid and fixed deformities in the medium- to long-term follow-up, with lasting improvements in AOFAS and VAS scores. The procedure is characterised by a non-negligible risk of complications, reoperations and revisions.Level of evidenceLevel IV, case series.

Cartilage-sparing otoplasty – 288 ears in 3 years

BackgroundStandard methods of otoplasty may risk anatomical distortion. Previous work showcased a novel, cartilage-sparing technique. This study aimed to confirm the safety and effectiveness of the method in a larger cohort. MethodsThis retrospective study included patients undergoing otoplasty by a single surgeon using a single technique between January 2021 and December 2023. Eligible patients were aged above 5 years and had prominent or constricted or cup ears, forming a 2cm distance from the mastoid. Surgical techniques included novel key-point sutures. Minimum follow-up was 6 months. Data on demographics, risk factors, perioperative management, and complications were collected from patient records. ResultsA total of 288 operated ears (147 patients) were included. The mean age was 17 years and 91 (61.9%) were female. The mean duration of follow-up was 24.3 months. Postoperative complications were generally minor and included PDS suture exposure (n=16, 5.5%), manageable postoperative pain (n=8, 2.7%), self-resolving swelling (n=8, 2.7%), minor bleeding (n=7, 2.4%), and superficial skin complications (n=4, 1.3%). Infections occurred in 4 ears (1.3%) and were treated effectively with topical/oral antibiotics. Cases of partial release of the ear resolved without intervention (n=4, 1.3%). Only 4 (1.3%) ears experienced loss of correction, with options for reoperation available as needed. Analysis showed no significant age differences in postoperative complications, and a nonsignificant trend towards higher postoperative swelling in males compared to females (10.7% vs 2.2%; P=0.054). ConclusionsThe data confirms that this technique offers a safe and rapid cartilage-sparing otoplasty with minimal complications and low recurrence rates. It ensures long-lasting and aesthetically pleasing results for prominent ear deformities. Level of evidenceLevel III

Midterm Outcomes of Multimodal Approach to Treating Severe Scoliosis in Patients With Osteogenesis Imperfecta.

The surgical management of severe scoliosis in patients with osteogenesis imperfecta (OI) is challenging because of curve rigidity, small stature, and inherent bone fragility. This study evaluated the midterm outcomes of our multimodal approach to address these issues, integrating perioperative bisphosphonate therapy, preoperative/intraoperative traction, various osteotomies, segmental pedicle screw instrumentation with cement augmentation, and bone morphogenetic protein-2 application. A single-center retrospective review of 30 patients (average age 14.1 ± 2.2 years; 18 were female) diagnosed with OI and scoliosis was conducted. These patients underwent posterior spinal fusion between 2008 and 2020 and completed a minimum follow-up of 2 years. We measured radiographic parameters at each visit and reviewed the incidence of complications. A mixed-effects model was used to evaluate changes in radiographic parameters from preoperative measurements to the first and latest follow-ups. The patient cohort consisted of 2 individuals with type I OI, 20 with type III, 6 with type IV, and 2 with other types (types V and VIII). Surgical intervention led to a notable improvement in the major curve magnitude from 76° to 36°, with no notable correction loss. In addition, the minor curve, apical vertical translation, lowest instrumented vertebra tilt, and pelvic obliquity were also improved. In the sagittal plane, thoracic kyphosis and lumbar lordosis remained unchanged while thoracolumbar kyphosis markedly improved. Two patients experienced proximal junctional kyphosis with screw pullout, one of whom required revision surgery. One patient developed a superficial infection that was successfully treated with oral antibiotics. No instances of neurologic deficits or cement extravasation were observed. This study demonstrated the effectiveness and safety of our multimodal approach to treating scoliosis in patients with OI, achieving a 53% major curve correction with minimal complications over 2-year follow-up. These findings provide notable insights into managing scoliosis in this population. Level IV (case series).

Percutaneous functional spinal unit cementoplasty versus percutaneous kyphoplasty for severe osteoporotic vertebral compression fracture complicated with endplate-disc complex injury: A retrospective case-control study.

Severe osteoporotic vertebral compression fracture (SOVCF) is frequently complicated by endplatedisc complex (EDC) injury. While percutaneous kyphoplasty (PKP) can offer rapid analgesia and facilitate early activity, it does not restore vertebral height and may result in intervertebral leakage and untreated EDC injury. This study aimed to evaluate the clinical outcomes of percutaneous functional spinal unit cementoplasty (PFSUP) for SOVCF complicated by EDC injury and compare its clinical and imaging outcomes with PKP. This was a retrospective case-control study. Patients with SOVCF complicated with EDC injury between January 1, 2018, and December 31, 2019, were recruited and assigned to the PKP group and PFSUP group based on their treatment procedures Back pain was evaluated using the visual analog scale (VAS) and daily life activities were assessed using the Oswestry disability index (ODI). X-rays were employed to observe the presence and location of cement leakage, as well as to measure the sagittal vertical axis (SVA) and local kyphosis angle (LKA). Loss of correction was calculated by subtracting the LKA after surgery from that at the final follow-up visit Subsequent vertebral fracture (SVF) was confirmed using the Genant semi-quantitative method and/or MRI. A total of 64 patients were included in this study. Among them 41 cases were assigned to the PKP group (28 females, 74.8 years on average), while the remaining 23 cases were assigned to the PFSUP group (15 females, 76.3 years on average). All surgical interventions were successfully completed without major complications. Compared to the PKP group, the PFSUP group had longer operation time (70.28 ± 11.44 vs 44.5 ± 10.12, P< 0.001) higher frequencies of radiation exposure (97.6 ± 19.85 vs 38.6 ± 9.53, P< 0.001), and a lower cement leakage rate (26.1% vs. 41.5%, P< 0.001). One day after surgery and at the final follow-up the PFSUP group had lower VAS and ODI scores, as well as lower LKA and Sva values compared with the PKP group (all P< .001). At the final follow-up visit, the PFSUP group demonstrated a lower loss of correction (4.38 ± 2.71 vs. 10.19 ± 3.41 P< 0.001) and a lower SVF rate compared to the PKP group (21.7% vs. 31.7%, P< 0.001). PFSUP outperformed PKP in alleviating pain restoring and maintaining sagittal balance, and lowering the incidence of cement leakage and SVF for SOVCF with EDC injury However, PFSUP was associated with longer operation time and high radiation exposure frequencies.

304 Amino acid digestibility and protein quality of fermented soybean-based ingredients using the precision-fed cecectomized rooster assay

Abstract Fermented soybean-based ingredients may serve as an alternative protein source for pet foods because of their high-quality protein content. The amino acid (AA) content and protein quality of fermented soybean-based ingredients may vary depending on their composition and processing, however, so testing is required. Our objective was to measure the AA composition, AA digestibility, and protein quality of fermented soybean-based ingredients using the precision fed cecectomized rooster assay. The University of Illinois Institutional Animal Care and Use Committee approved all animal procedures prior to experimentation. Cecectomized roosters (n = 36; six roosters per substrate) were randomly allotted to one of five test substrates: 1) autoclaved soybean (ASB); 2) fermented soybeans (FSB); 3) fermented soybeans with probiotics (FSBP); 4) fermented soybean meal (FSBM); 5) fermented soybean meal with probiotics (FSBMP). After 26 h of feed withdrawal, roosters were tube-fed test substrates. Following crop intubation excreta samples were collected 48 h. Endogenous loss corrections for AA were made by using five additional cecectomized roosters. All data were analyzed using SAS version 9.4. All substrates had increased AA digestibilities, with all indispensable AA digestibilities being &amp;gt;80% except for lysine (78.1% to 86.9%). Tryptophan digestibility was less (P &amp;lt; 0.05) in FSB than other substrates, but other AA digestibilities were not different. Digestible indispensable AA score (DIAAS)-like values were calculated to determine protein quality according to nutritional guidelines for adult dogs, adult cats, growing puppies, and growing kittens. The most limiting AA was the same for all ingredients. In adult dogs, methionine was the most limiting AA based on National Research Council (NRC; DIAAS: 33.4-35.1), European Pet Food Industry Nutritional Guidelines (FEDIAF; DIAAS: 49.6-52.1), and Association of American Feed Control Officials (AAFCO; DIAAS: 60.2-63.2) guidelines. In adult cats, phenylalanine was the most limiting AA (DIAAS: 59.5-63.2) when using NRC guidelines, but DIAAS were above 100 for FEDIAF and AAFCO guidelines. In growing puppies, methionine was most limiting according to NRC (DIAAS: 56.7-59.6) and FEDIAF (DIAAS: 78.8-82.7) guidelines, but threonine was most limiting according to AAFCO (DIAAS: 68.8-72.3) guidelines. In growing kittens, methionine was most limiting according to NRC (DIAAS: 70.9-74.4) and AAFCO (53.4-56.0) guidelines, but phenylalanine was most limiting according to FEDIAF (DIAAS: 66.7-70.8) guidelines. Our results demonstrate that fermented soybean-based ingredients are high-quality protein sources. Even though they have one or more limiting AA, they would serve as strong complementary proteins for pet foods. Further research in dogs and cats is necessary to confirm sufficient palatability and digestibility, but these data suggest that they are valuable sources of protein for pet food.

Orthodontic re-treatment of class II malocclusion – Strategies for correction of anchorage loss

Orthodontic re-treatment may be required in cases of sub-optimal treatment outcomes. These outcomes may often be due to appliance-driven treatment plan, inadequate bio-mechanical considerations during treatment or poor operator skills. Common issues include anchorage loss, deepening of bite, incorrect extraction protocols, re-opened extraction spaces and loss of vertical control. To address these problems, traditional orthodontic appliances, skeletal anchorage systems, customized appliances, and clear aligners may offer a ray of hope, provided they are used judiciously. To effectively manage re-treatment techniques, it's important to have a solid understanding of the anatomic limits, biomechanics, and potential side effects. Proper case selection is extremely crucial for overall clinical success in such complex situations. Therefore, establishing guidelines and understanding the biomechanical perspectives of various appliance systems are essential to address these challenges in modern orthodontic practice.

Comparative clinical and radiographic results of three fixation systems for transverse subcapital osteotomy in treating hallux valgus

Objective: Compare three fixation models for Bosch osteotomy both clinically and radiographically.Methods: A retrospective comparative study was conducted on patients surgically treated for hallux valgus using Bosch osteotomywith three different fixation systems. The first group was treated with a temporary pin for three weeks; the second, received thesame pin plus a screw; and the third, used two screws without a pin. Radiographic analysis included the intermetatarsal angle,metatarsophalangeal angle, percentage of lateral shifting of the metatarsal head, dorsal or plantar migration of the metatarsal head,and consolidation time. Clinical evaluation was performed using the American Orthopaedic Foot and Ankle Society (AOFAS) scale.Complications during follow-up were recorded.Results: Twenty hallux valgus were included in each group. No significant differences were found in radiographic evaluations amonggroups in the preoperative and final follow-up, except that the third group showed less loss of correction. There were no significantdifferences in consolidation times. Clinical improvements were observed in all three fixation systems, with no significant differencesamong them according to the AOFAS scale.Conclusion: No significant clinical or radiographic differences were observed among the three fixation systems, except that the groupusing two screws showed less loss of correction. Level of evidence IV; Therapeutic studies; Case series.

Is the use of neuromonitoring necessary in Sprengel's deformity surgery?

This study aimed to emphasize the effectiveness of using intraoperative neuromonitoring (IONM) in preventing possible nerve damage in Sprengel's deformity surgery. Eighteen patients who underwent Woodward surgery accompanied by neuromonitoring due to Sprengel's deformity were included in the study. Demographic information of the patients and their clinical and cosmetic results before and after surgery were recorded. Complications that occurred during and after the surgery were recorded. Of the 18 patients who underwent surgery, 12 were female and 6 were male. The mean age of the patients was 4.4 (2-8). The mean shoulder abduction angle of the patients was 84.4 (65-105) degrees before the surgery and 151.1 (125-175) degrees in the first year after the surgery. The mean Cavendish score of the patients was 3.6 (3-4) before the surgery and 1.1 (1-2) in the first year after the surgery. In one patient, there was a decrease in IONM motor-evoked potency signals during the reduction of the intraoperative scapula. Considering some loss of correction in the deformity, the scapula was detected at the point where there was no loss of signals. No patients developed wound problems or infections. In this study, it was determined that the use of neuromonitoring was effective in preventing brachial plexus damage, even if this complication was minimal in patients operated on due to Sprengel's deformity.

Impact of fuel dilution on Lawson parameter by considering relativistic correction of radiation loss in toroidal magnetic configuration

In this paper, the ignition boundary and height of the saddle point as the lowest heating power on the way to ignition for D-3He toroidal magnetic configuration are derived. Fusion fuel cycle involving deuterium and helium-3, along with side reactions is considered. The effect of fuel dilution, incorporating synchrotron radiation and bremsstrahlung power loss with relativistic correction on ignition criteria, is investigated. The results were compared by considering the classical state of bremsstrahlung power. It is found that the height of the saddle point is increased with increasing the ratio of the proton particle density to the fuel deuteron density. The ignition regime shrinks and the minimum value of the Lawson parameter for the breakeven condition and ignition boundaries is reduced due to fuel dilution.

Performance Estimation of Fixed-Wing UAV Propulsion Systems

The evaluation of propulsion systems used in UAVs is of paramount importance to enhance the flight endurance, increase the flight control performance, and minimize the power consumption. This evaluation, however, is typically performed experimentally after the preliminary hardware design of the UAV is completed, which tends to be expensive and time-consuming. In this paper, a comprehensive theoretical UAV propulsion system assessment is proposed to assess both static and dynamic performance characteristics via an integrated simulation model. The approach encompasses the electromechanical dynamics of both the motor and its controller. The proposed analytical model estimates the propeller and motor combination performance with the overarching goal of enhancing the overall efficiency of the aircraft propulsion system before expensive costs are incurred. The model embraces an advanced blade element momentum theory underpinned by the development of a novel mechanism to predict the propeller performance under low Reynolds number conditions. The propeller model utilizes XFOIL and various factors, including post-stall effects, 3D correction, Reynolds number fluctuations, and tip loss corrections to predict the corresponding aerodynamic loads. Computational fluid dynamics are used to corroborate the dynamic formulations followed by extensive experimental tests to validate the proposed estimation methodology.

The Research on Spinopelvic Parameters and Clinical Outcomes of Oblique Lumbar Interbody Fusion and Transforaminal Lumbar Interbody Fusion in the Treatment of Complex Degenerative Lumbar Spondylolisthesis

PurposeTo investigate the improvement of spinopelvic parameters and therapeutic efficacy in the treatment of complex degenerative lumbar spondylolisthesis (CDLS) after OLIF and TLIF. MethodsFrom January 2018 to December 2020, 71 patients with CDLS underwent OLIF or TLIF at the same hospital: 31 in the OLIF group and 40 in the TLIF group. The spinopelvic parameters, perioperative data and clinical outcomes were elected and compared between the two groups. ResultsThere were no statistic differences in demographic, perioperative complication rates and preoperative spinopelvic parameters between the two groups. OLIF group showed lower serum C-reactive protein (CRP) in the early postoperative stage, shorter length of stay (LOS), less estimated blood loss (EBL) and larger slippage correction rate (SCR, 88.05 vs 62.37%) (all P＜0.05). There was no significant difference in the VAS and ODI scores before operation and three and six months after surgery, but OLIF group was better in the long-term with VAS and ODI (1.7/13.2vs 2.3/16.5). And it was significantly different in the lumbar lordosis angle (LLA), segmental lordosis angle (SLA), pelvic tilt (PT), sacral slope (SS)( 46.0°/9.3°/18.2°/35.9° vs 40.4°/7.2°/23.9°/31.1°) and sagittal vertical axis (SVA, 21.6 vs 31.7mm) after surgery between OLIF and TLIF groups (all P＜0.05). ConclusionIn the therapy of CDLS, OLIF can better reduce PT, LASD and SVA, and increase LLA and SS, showing advantages over TLIF in improving and maintaining spinopelvic parameters. Although there was no difference in complication rates between OLIF and TLIF, OLIF was more minimally invasive, had less tissue damage, had faster recovery, and had better long-term outcomes.

Outcomes of Thoracolumbar Burst Fractures Treated With Open Versus Minimally Invasive Percutaneous Posterior Spinal Stabilization: A Retrospective Study at a Rural Teaching Hospital in South India.

Background Thoracolumbar spine fractures are the most prevalent type of axial skeleton fractures, with approximately two-thirds occurring between T11 and L2. Percutaneous pedicle screw fixation has been reported to be an effective treatment for thoracolumbar fractures. Minimally invasive percutaneous pedicle screw fixation yields outcomes comparable to those of the standard open procedure and has the advantages of less stress, bleeding, and pain, as well as rapid postoperative recovery. The main objective of this research was to compare the clinical and radiological outcomes of two surgical approaches (open and percutaneous posterior spinal stabilization), concentrating on nonosteoporotic AO Spine Type A3 thoracolumbar burst fractures between T11 and L2. Materials and methods We conducted a retrospective study in our hospital, where cases of thoracolumbar burst fractures meeting the inclusion criteria were chosen retrospectively from April 2022 to March2023. A total of 54 patients (aged 18-60 years) who underwent spinal stabilization were included in this investigation. The population was divided into two cohorts, with 27 patients in each: Group A underwent open posterior spinal stabilization, and Group B underwent percutaneous posterior spinal stabilization. Data retrieved from medical records were analyzed with at least a six-month follow-up, mainly assessing the demographic data, intraoperative parameters, duration of hospitalization, clinical outcomes (Visual Analog Scale, Oswestry Disability Index, and McGill Pain Questionnaire scores), and radiological outcomes (vertebral wedge angle and correction loss). Results Both groups had a male preponderance. There were statistically meaningful distinctions between both groups regarding intraoperative parameters (blood loss and surgical duration) and primary clinical outcome parameters (Visual Analog Scale, Oswestry Disability Index, and McGill Pain Questionnaire scores) in the early phase of the study. However, there were no statistically significant differences concerning radiological parameters (vertebral wedge angle and correction loss) or primary clinical outcome parameters at the last follow-up. Conclusion The treatment modalities (open and percutaneous posterior spinal stabilization surgery) were equally safe and effective. However, the percutaneous group demonstrated significant reductions in the length of the surgical procedure, blood loss during surgery, duration of hospital stay, and immediate postoperative pain scores, all of which could potentially benefit patients.

Investigation of the Usefulness of Implants With Locking Mechanisms for Diffuse Idiopathic Skeletal Hyperostosis (DISH)-Induced Thoracic and Lumbar Fractures in Patients Operated in the Prone Position.

Background Diffuse idiopathic skeletal hyperostosis (DISH) is a disease that causes bone growth in the spine and musculoskeletal system, and even minor trauma can cause fractures that often require surgery. DISH-induced fractures show a tendency for bone loss when operated in the prone position, which can lead to poor fusion and implant failure; therefore, surgery in the lateral recumbent position is often recommended. However, inserting a pedicle screw (PS) in the lateral recumbent position is technically difficult. This study examined the effectiveness of the repair and fixation of thoracic and lumbar spine fractures using implants with locking mechanisms in the prone position in patients with DISH. Methods We retrospectively analyzed the data from 11 patients (six males and five females; mean age: 87 years) who underwent surgery for thoracic and lumbar fractures caused by DISH between December 2023 and June 2024. Surgery was performed in the prone position using PSs or transdiscal screws (TSDs) for DISH. Ennovate® implants manufactured by B-BRAUN were used. The fixed range was three above-three below for PSs and two above-two below for TSDs. The evaluation parameters were the height/level of injury, operative time, blood loss, local kyphosis angle, anterior wall height ratio, and complications. The local kyphosis angle was measured as the angle between the upper and lower endplates of the fractured vertebrae. The ratio of the anterior wall height was evaluated. Results The average operative time was 87 min (52-172 min), and the average blood loss was 40ml (10-140 ml). The preoperative and postoperative local kyphosis angle was -8.7° and -2.4°, respectively, and the average local kyphosis angle improvement was 6.3° (0.1-14°). The preoperative and postoperative anterior wall height ratio was 132% and 110%, respectively, and the average anterior wall height ratio improvement was 22% (2-82%). No complications, such as screw deviation, implant loosening, loss of correction, or skin problems, were observed. Conclusion This study demonstrated that DISH-induced thoracic and lumbar spine fractures could be repaired and fixed using implants with locking mechanisms in the prone position. The prone position is familiar to spine surgeons and is considered safe. Additionally, screw migration may occur due to decreased bone density in the vertebral bodies with DISH; in such cases, it would be better to fix the screw without forcing it to be repositioned.