Successful Reconstruction Research Articles

Enhancing the spatial resolution of time-of-flight based non-line-of-sight imaging via instrument response function deconvolution.

Non-line-of-sight (NLOS) imaging retrieves the hidden scenes by utilizing the signals indirectly reflected by the relay wall. Benefiting from the picosecond-level timing accuracy, time-correlated single photon counting (TCSPC) based NLOS imaging can achieve theoretical spatial resolutions up to millimeter level. However, in practical applications, the total temporal resolution (also known as total time jitter, TTJ) of most current TCSPC systems exceeds hundreds of picoseconds due to the combined effects of multiple electronic devices, which restricts the underlying spatial resolution of NLOS imaging. In this paper, an instrument response function deconvolution (IRF-DC) method is proposed to overcome the constraints of a TCSPC system's TTJ on the spatial resolution of NLOS imaging. Specifically, we model the transient measurements as Poisson convolution process with the normalized IRF as convolution kernel, and solve the inverse problem with iterative deconvolution algorithm, which significantly improves the spatial resolution of NLOS imaging after reconstruction. Numerical simulations show that the IRF-DC facilitates light-cone transform and frequency-wavenumber migration solver to achieve successful reconstruction even when the system's TTJ reaches 1200 ps, which is equivalent to what was previously possible when TTJ was about 200ps. In addition, the IRF-DC produces satisfactory reconstruction outcomes when the signal-to-noise ratio (SNR) is low. Furthermore, the effectiveness of the proposed method has also been experimentally verified. The proposed IRF-DC method is highly applicable and efficient, which may promote the development of high-resolution NLOS imaging.

Nunchaku-like Free Fibula Osteocutaneous Flap in Through-and-through Composite Oromandibular Defect Reconstruction.

The free fibula osteocutaneous flap (FFOCF) has been used for oromandibular reconstruction over several decades. However, when facing through-and-through composite oromandibular defects (COMDs), significant challenges still arise. The complexity of COMD necessitates the reconstruction of bone, intraoral mucosa, and extraoral skin. Additional flaps are often needed, which extend surgical durations and heighten associated risks. This report presents a 62-year-old man with squamous cell carcinoma of the left lower gingiva. After ablative surgery, successful reconstruction of a through-and-through COMD was achieved with a single FFOCF through innovative design. The flap was osteotomized into 2 segments with attached skin islands while preserving the vascular pedicle. Rotation of 1 segment created 2 skin islands on opposing sides, simultaneously repairing intraoral and extraoral defects. Postoperative outcomes at the 1-month follow-up were encouraging. Although technically challenging, the "Nunchaku-like FFOCF" offers a safe and effective approach for the comprehensive reconstruction of through-and-through COMD.

Two-stage microsurgical soft tissue reconstruction of a complex sacral wound using an arteriovenous loop

The surgical reconstruction of sacral soft tissue defects is challenging, and complications are frequent. We report a successful two-stage three-dimensional microsurgical soft tissue reconstruction of a wide and deep sacral defect anastomosing a free combined ALT/TFL/rectus femoris flap to an ipsilateral vena saphena magna arteriovenous loop which was applied primarily. This case shows that complex microsurgical procedures can be promising in this demanding patient population if the indication is correct and the operative/perioperative strategy is clear.

Evaluating the Point Cloud of Individual Trees Generated from Images Based on Neural Radiance Fields (NeRF) Method

Three-dimensional (3D) reconstruction of trees has always been a key task in precision forestry management and research. Due to the complex branch morphological structure of trees themselves and the occlusions from tree stems, branches and foliage, it is difficult to recreate a complete three-dimensional tree model from a two-dimensional image by conventional photogrammetric methods. In this study, based on tree images collected by various cameras in different ways, the Neural Radiance Fields (NeRF) method was used for individual tree dense reconstruction and the exported point cloud models are compared with point clouds derived from photogrammetric reconstruction and laser scanning methods. The results show that the NeRF method performs well in individual tree 3D reconstruction, as it has a higher successful reconstruction rate, better reconstruction in the canopy area and requires less images as input. Compared with the photogrammetric dense reconstruction method, NeRF has significant advantages in reconstruction efficiency and is adaptable to complex scenes, but the generated point cloud tend to be noisy and of low resolution. The accuracy of tree structural parameters (tree height and diameter at breast height) extracted from the photogrammetric point cloud is still higher than those derived from the NeRF point cloud. The results of this study illustrate the great potential of the NeRF method for individual tree reconstruction, and it provides new ideas and research directions for 3D reconstruction and visualization of complex forest scenes.

Economic Depression and Recovering from the Trauma of the World War: The Social Reconstruction of Britain after World War II

The passage focuses on the reconstruction of Britain after World War II. The background of the research was the time period after WWII. In order to analyze the situation more precisely, the background information of the research had a time span from the 1920s to approximately the 1950s, starting from the Roaring Twenties to the publication of the Green Belt Policy. The passage focuses on the reorganization of cities and the reconstruction of the welfare system. The two examples listed in the following passage are the Green Belt Policy and the NHS, which represents the reconstruction of cities in England and the reconstruction of the welfare system of England. Other examples include data recorded in 1931 and several government documents by the British government. By answering the question of the advantages of Britain in the reconstruction of World War II, the passage hopes to provide some characteristics of the successful reconstruction of Britain to help reconstruction in other countries like Palestine.

Successful soft tissue reconstruction using acellular fish skin grafts in a secondary blast war injury.

Successful soft tissue reconstruction using acellular fish skin grafts in a secondary blast war injury.

Roles of pore architecture of artificial bone grafts in invasion competition between bone and fibrous tissue and orientation of regenerated bone

 In the reconstruction of bone defects close to soft tissue, preventing the invasion of fibrous tissue into the bone defect is key to successful bone reconstruction. In this study, we clarified the effects of the pore architecture of artificial bone grafts on the penetration of bone and fibrous tissue, and the orientation of regenerated bone. Carbonate apatite grafts with uniaxial pores along the long- (L-graft) or short-axis (S-graft) direction of the graft and biaxial pores along the long- and short-axes (LS-graft) were used. These grafts were implanted in bone defects created by rabbit ulnae amputation. The pores of the L-, S-, and LS-grafts opened into the bone stumps, muscles, and bone stumps and muscles together, respectively. In the L-graft, the graft pores developed bone from the bone stump to the graft center, while preventing excessive invasion of fibrous tissue. In S- and LS-grafts, the graft pores along the short axis allowed the invasion of fibrous tissue into the grafts. Consequently, although the bone grew to the edge regions in these grafts, further bone ingrowth was inhibited by the fibrous tissue. Furthermore, the pore architecture of the grafts affected the orientation of the regenerated bone. The degree of orientation of the bone formed in the L- and S-grafts was 1.6-fold higher than that formed in the LS-grafts. Thus, controlling the pore architecture allowed the growth of bone to predominate over that of fibrous tissue and induced the formation of bone with an ordered orientation

Successful microvascular surgery in patients with thrombophilia in head and neck surgery: a case series

BackgroundIn this case series, a perioperative anticoagulation protocol for microvascular head and neck surgery in patients with thrombophilia is presented. Microvascular free-flap surgery is a standard procedure in head and neck surgery with high success rates. Nevertheless, flap loss—which is most often caused by thrombosis—can occur and has far-reaching consequences, such as functional impairment, prolonged hospitalization, and increased costs. The risk of flap loss owing to thrombosis is significantly increased in patients with thrombophilia. Therefore, perioperative anticoagulation is mandatory. To date, no perioperative anticoagulation protocol exists for these high-risk patients.Case presentationWe present three exemplary male Caucasian patients aged 53–57 years with free flap loss owing to an underlying, hidden thrombophilia.ConclusionWe present a modified anticoagulation protocol for microvascular surgery in these high-risk patients, enabling successful microsurgical reconstruction.

Survival analysis of PLWHA undergoing combined antiretroviral therapy: exploring long-term prognosis and influencing factors.

The survival time of human immunodeficiency virus (HIV)-infected individuals or patients with acquired immunodeficiency syndrome (AIDS) is influenced by multiple factors. Studying survival and influential factors after antiretroviral therapy (ART) contributes to improving treatment protocols, management strategies, and prognosis for people living with HIV/AIDS (PLWHA). This retrospective cohort study collected case data and follow-up records of PLWHA who received ART in Dazu District, Chongqing City, between 2007 and 2022. Cumulative survival rates were calculated using life tables. Survival curves were plotted using the Kaplan-Meier method. Uni-variable and multivariable Cox proportional hazards models analyzed factors influencing survival. The study included 5,237 PLWHA receiving ART. Within the first year of ART initiation, 146 AIDS-related deaths occurred, accounting for 29.49% (146/495) of total deaths. Cumulative survival rates at 1, 5, 10, and 15 years were 0.97, 0.90, 0.85, and 0.79, respectively. During the observation period, male patients who received ART had a 1.89 times higher risk of death compared to females (aHR, 1.89; 95%; CI, 1.50-2.37). Patients aged ≥60 years had a 3.44-fold higher risk of death than those aged <30 years (aHR, 3.44; 95% CI, 1.22-9.67). Injection drug users (aHR, 4.95; 95% CI, 2.00-12.24) had a higher risk of death than those with heterosexual (aHR, 1.60; 95% CI, 0.69-3.72) and homosexual transmission. Patients with a baseline CD4+ T lymphocyte count <200 cells/μL (aHR, 8.02; 95% CI, 4.74-13.57) and between 200 and 349 cells/μL (aHR, 2.14; 95% CI, 1.26-3.64) had a higher risk of death than those with ≥350 cells/μL. Patients with ART initiation at WHO clinical stage IV had a 2.48-fold higher risk of death than those at stage I (aHR, 2.48; 95% CI, 1.17-5.23). The first year following ART initiation is critical in HIV/AIDS treatment, emphasizing the need for intensified follow-up and monitoring to facilitate successful immune system reconstruction. Older age, male sex, injection drug use, baseline CD4+ T lymphocyte count <200 cells/μL, and WHO clinical stage IV are associated with an increased risk of death. Tailored treatment and management strategies should be implemented for patient populations at higher risk of mortality and with a poorer prognosis.

Marginal Tension Release Method of Nasoseptal Flap During Reconstruction of Skull Base Defect

The successful reconstruction of anterior skull base defects following transcribriform or transsphenoidal surgery is pivotal in mitigating the communication between the external environment and the cranial cavity. This intervention is crucial to prevent potential complications, including cerebrospinal fluid leakage and meningitis. The ideal reconstructive flap should possess sufficient vascularity and be of ample size to adequately cover vital nerves and vessels. Predominantly, the nasoseptal flap is employed for the repair of skull base defects. This flap is vascularized by the posterior division of the sphenopalatine artery, ensuring sufficient coverage of the defects. A significant advantage of the nasoseptal flap is its rotational capability, allowing for mobilization and repositioning to effectively cover the defect. Nonetheless, the rotational tension on the nasoseptal flap running from the nasal cavity to the skull base may affect the distal margin of the flap. Alleviation of this tension can be achieved through the insertion of multiple minuscule incisions in the vertical axis of the flap’s border. This report introduces and elaborates on this technique.

Evaluation on improved sparse signal reconstruction algorithm for trusted AI and DCS technology

The improved Sparse Signal Reconstruction (SR) algorithm for Trusted Artificial Intelligence (AI) and Distributed Compressed Sensing (DCS) technology was thoroughly investigated. The study verified its effectiveness and advantages in trusted AI and DCS systems, which have significant implications for enhancing the credibility, security, and performance of signal processing and AI algorithms. The reconstruction performance was evaluated using Orthogonal Matching Pursuit (OMP), Basis Pursuit (BP), and Least Absolute Shrinkage and Selection Operator (LASSO). The analysis primarily focused on runtime, refactoring errors, and the number of successful reconstruction attempts. When K = 4, K = 6, K = 8, and K = 10, OMP outperformed BP and LASSO in terms of successful reconstructions, demonstrating better performance and higher reconstruction precision.

Reconstruction of the elbow with distal humerus endoprosthetic replacement after tumor resection: a systematic review of the literature and institutional case series

Distal humerus replacement (DHR) is a modular endoprosthesis mainly used for bone reconstruction after resection of primary or metastatic bone lesions. Studies on DHR failure rates and postoperative functional outcomes are scarce. We sought to assess implant survival, modes of failure, and functional outcomes in patients undergoing DHR for oncologic indications. A systematic review of the PubMed and Embase databases was performed. PRISMA guidelines were followed for this manuscript. Our study was registered on PROSPERO (457,260). Quality appraisal of included studies was conducted using the STROBE checklist. Prosthetic failure was assessed using the Henderson classification for megaprosthetic failures. We additionally performed a retrospective review of patients treated with a DHR for oncologic indications at a large tertiary care academic center. Weighted means were calculated to pool data. Eleven studies with a total of 162 patients met the inclusion criteria. Mean follow-up was 3.7years (range, 1.66-8years). Henderson type 2 failures (aseptic loosening) were the most common mode of failure, occurring in 12% of cases (range, 0%-33%). Five-year implant survival was 72% (range, 49%-93.7%). Mean postoperative Musculoskeletal Tumor Society (MSTS) score was 81.1 (range, 74-84.3). In our institutional case series, 2 out of 5 patients had DHR revision for periprosthetic fracture and aseptic loosening at 16 and 27months after surgery, respectively. Distal humerus replacement is a successful reconstruction strategy for tumors of the distal humerus, with high implant survival and good to excellent functional outcomes.

Advanced Time-Stepping Interpretation of Fly-Scan Continuous Rotation Synchrotron Tomography of Dental Enamel Demineralization.

High-resolution spatial and temporal analysis and 3D visualization of time-dependent processes, such as human dental enamel acid demineralization, often present a challenging task. Overcoming this challenge often requires the development of special methods. Dental caries remains one of the most important oral diseases that involves the demineralization of hard dental tissues as a consequence of acid production by oral bacteria. Enamel has a hierarchically organized architecture that extends down to the nanostructural level and requires high resolution to study its evolution in detail. Enamel demineralization is a dynamic process that is best investigated with the help of in situ experiments. In previous studies, synchrotron tomography was applied to study the 3D enamel structure at certain time points (time-lapse tomography). Here, another distinct approach to time-evolving tomography studies is presented, whereby the sample image is reconstructed as it undergoes continuous rotation over a virtually unlimited angular range. The resulting (single) data set contains the data for multiple (potentially overlapping) intermediate tomograms that can be extracted and analyzed as desired using time-stepping selection of data subsets from the continuous fly-scan recording. One of the advantages of this approach is that it reduces the amount of time required to collect an equivalent number of single tomograms. Another advantage is that the nominal time step between successive reconstructions can be significantly reduced. We applied this approach to the study of acidic enamel demineralization and observed the progression of demineralization over time steps significantly smaller than the total acquisition time of a single tomogram, with a voxel size smaller than 0.5 μm. It is expected that the approach presented in this paper can be useful for high-resolution studies of other dynamic processes and for assessing small structural modifications in evolving hierarchical materials.

Pediatric Robot-Assisted Laparoscopic Pyeloplasty: Where Are We Now?

This review aims to provide an in-depth exploration of the recent advancements in robot-assisted laparoscopic pyeloplasty (RALP) and its evolving landscape in the context of infant pyeloplasty, complex genitourinary (GU) anatomy, recurrent ureteropelvic junction (UPJ) obstruction, cost considerations, and the learning curve. Recent literature highlights the safety and efficacy of RALP in treating the infant population, patients with complex GU anomalies, and recurrent UPJO which were all traditionally managed using the open approach. Cost considerations are evolving, with the potential for RALP to have a lesser financial burden. In addition, the learning curve for RALP is diminishing due to robust training programs and advances in research. RALP has become the gold standard in the treatment of UPJO in pediatric urology at many children's hospitals. Surgeon comfort and research in this space allow safe and successful reconstruction in the most challenging of cases.

Mapping Motor Neuroplasticity after Successful Surgical Brachial Plexus Reconstruction Using Navigated Transcranial Magnetic Stimulation (nTMS).

Brachial plexus reconstruction (BPR) consists of the complex surgical restoration of nerve structures. To further understand the underlying motor cortex changes and evaluate neuroplasticity after a successful surgery, we performed a navigated transcranial magnetic stimulation (nTMS) study mapping the postoperative motor representation of the formerly plegic arm. We conducted a prospective nTMS study mapping the musculocutaneous nerve as a representative, prominent target of BPR including a patient (n = 8) and a control group (n = 10). Measurements like resting motor threshold (RMT), cortical motor area location, and size were taken. Mathematical analysis was performed using MATLAB 2022, statistical analysis was performed using SPSS 26, and nTMS mapping was performed using the Nexstim NBS 5.1 system. Mapping was feasible in seven out of eight patients. Median RMT on the affected hemisphere was 41% compared to 50% on the unaffected hemisphere and they were 37% and 36% on the left and right hemispheres of the control group. The motor area location showed a relocation of bicep brachii representation at the middle precentral gyrus of the corresponding contralateral hemisphere. Motor area size was increased compared to the control group and the patient's unaffected, ipsilateral hemisphere. Understanding cortical reorganization is important for potential future treatments like therapeutic nTMS. The issue of motor neuroplasticity in patients with brachial plexus lesions is worth exploring in further studies.

Revision ACL reconstruction in female athletes: current concepts

The challenge of revision anterior cruciate ligament (ACL) reconstruction lies in its complexity, varied presentation, and technical intricacies. A successful ACL reconstruction should allow patients to safely return to preinjury activities. However, it is only sometimes simple, and many risk factors and concurrent pathologies come into play. Evaluating and analysing the cause of failure and associated conditions is paramount to addressing them effectively. Despite a plethora of research and improvements in knowledge and technology, e gaps exist in issues such as optimal techniques of revision surgery, graft options, fixation, concurrent procedures, rehabilitation and protocol for return to sports of high-level athletes. Female athletes need additional focus since they are at higher risk of re-injury, suboptimal clinical outcomes, and lower rates of return to sport following revision reconstruction. Our understanding about injury prevention and the protection of ACL grafts in female athletes needs to be improved. This review focuses on the current state of revision ACL surgery in female athletes and provides recommendations and future directions for optimising outcomes in this high-risk group.

Prediction model for haematoma after tissue expander placement: A retrospective cohort study of 7080 cases over 20 years

Haematoma is an early complication of tissue expander placement and can lead to infection, capsule contracture and various complications, hindering successful reconstruction. However, no scientific models can accurately predict the risk of haematoma following tissue expansion. Therefore, this study aimed to develop and validate a prediction model for haematoma following tissue expander placement. The medical records of patients who underwent expander placement between 2001 and 2021 were obtained from the clinical database of the Department of Plastic Surgery at the Xijing Hospital. A total of 4579 consecutive patients with 7080 expanders and 179 expanded pocket haematomas were analysed. Multivariate logistic regression analysis identified adult age (P = 0.006), male sex (P < 0.001), scar reconstruction (P = 0.019), perioperative hypertension (P < 0.001), face and neck location (P = 0.002) and activated partial thromboplastin time above the normal range (P < 0.001) as risk factors for haematoma. Therefore, these were included in the prediction model, and a nomogram was constructed. The discrimination of the nomogram was robust (area under the curve: 0.78; 95% confidence interval: 0.72–0.83). Further, the prediction model had a strong fit (Hosmer–Lemeshow test, P = 0.066) and maintained similar discrimination after considering performance optimism (bootstrapped area under the curve: 0.79; 95% confidence interval: 0.73–0.84). This clinical prediction model was created using a generalisable dataset and can be utilised to obtain valid haematoma predictions after expander placement, assisting surgeons in implementing preventive measures or interventions to reduce the occurrence of haematoma.

Efficacy of personalized 3D-printed osteotomy guide in maximizing fibular utilization and minimizing graft length for reconstruction of large mandibular defect.

The study addresses the long-standing challenge of insufficient length in vascularized fibular flaps when reconstructing large mandibular defects that require dual-barrel grafts. Employing personalized 3D-printed osteotomy guides, the study aims to optimize fibular utilization and minimize the required graft length. Two reconstruction methods for distal bone defects were compared: a fold-down (FD) group that employed a specialized osteotomy guide for folding down a triangular bone segment, and a traditional double-barrel (DB) group. Metrics for comparison included defect and graft lengths, as well as the graft-to-defect length ratio. Postoperative quality of life was assessed using the University of Washington Quality of Life questionnaire (UW-QoL). Both FD and DB groups achieved successful mandibular reconstruction. Despite larger defects in the FD group (117 ± 31.35mm vs 84 ± 35.34mm, p = 0.028), the used fibula length was not statistically longer in the FD group. The median ratio of graft-to-defect length was also lower in the FD group (1.327 vs 1.629, p = 0.024), suggesting that FD required only 82.47% of the graft length needed in the DB approach. Quality of life scores post-surgery were comparable between the groups. Personalized 3D-printed osteotomy guides enhance fibula graft efficacy for reconstructing larger mandibular defects, necessitating shorter graft lengths while preserving postoperative quality of life. This study confirms the utility of 3D printing technology as an effective and precise tool in orthopedic surgery, particularly for complex reconstructions like large mandibular defects. It suggests a viable alternative that could potentially revolutionize current practices in bone grafting.

X-ray phase and dark-field computed tomography without optical elements.

X-ray diffusive dark-field imaging, which allows spatially unresolved microstructure to be mapped across a sample, is an increasingly popular tool in an array of settings. Here, we present a new algorithm for phase and dark-field computed tomography based on the x-ray Fokker-Planck equation. Needing only a coherent x-ray source, sample, and detector, our propagation-based algorithm can map the sample density and dark-field/diffusion properties of the sample in 3D. Importantly, incorporating dark-field information in the density reconstruction process enables a higher spatial resolution reconstruction than possible with previous propagation-based approaches. Two sample exposures at each projection angle are sufficient for the successful reconstruction of both the sample density and dark-field Fokker-Planck diffusion coefficients. We anticipate that the proposed algorithm may be of benefit in biomedical imaging and industrial settings.

Trilayer composite scaffold for urethral reconstruction:in vitroevaluation of mechanical, biological, and angiogenic properties.

Regeneration of damaged urethral tissue remains a major challenge in the field of lower urinary tract reconstruction. To address this issue, various synthetic and natural biodegradable biomaterials are currently being explored for the fabrication of scaffolds that promote urethral regeneration and healing. In this study, we present an approach to fabricate a trilayer hybrid scaffold comprising a central layer of poly(lactic acid) (PLA) between two layers of chitosan. The chitosan/PLA/chitosan (CPC) scaffolds were fabricated by a sequential electrospinning process and their properties were evaluated for their suitability for urethral tissue engineering. The physical and biological properties of the CPC scaffolds were evaluated in comparison to electrospun PLA scaffolds and acellular dermis (Alloderm) as controls for a synthetic and a natural scaffold, respectively. Compared to the controls, the CPC scaffolds exhibited higher elastic modulus and ultimate tensile strength, while maintaining extensibility and suture retention strength appropriate for clinical use. The CPC scaffolds displayed significant hydrophilicity, which was associated with a higher water absorption capacity of the chitosan nanofibres. The degradation products of the CPC scaffolds did not exhibit cytotoxicity and promoted wound closure by fibroblastsin vitro. In addition, CPC scaffolds showed increased growth of smooth muscle cells, an essential component for functional regeneration of urethral tissue. Furthermore, in a chicken embryo-based assay, CPC scaffolds demonstrated significantly higher angiogenic potential, indicating their ability to promote vascularisation, a crucial aspect for successful urethral reconstruction. Overall, these results suggest that CPC hybrid scaffolds containing both natural and synthetic components offer significant advantages over conventional acellular or synthetic materials alone. CPC scaffolds show promise as potential candidates for further research into the reconstruction of the urethrain vivo.