Successful Reconstruction Research Articles

A Case of Oronasal Fistula Repaired With Inferior Turbinate Rotational Flap

Oronasal fistula is a rare but significant complication that diminishes the quality of life for patients undergoing treatment for cleft palate and head and neck cancer. Various surgical reconstruction methods can be used based on the size and location of the oronasal fistula. The intranasal inferior turbinate rotational flap is a simple and safe method for reconstructing the defect of nasal cavity. In this case report, we experienced a small oronasal fistula of a 50-year-old female caused by osteoradionecrosis after treatment for her malignant melanoma. Successful reconstruction was achieved with inferior turbinate rotational flap alone. For small oronasal fistula in the hard palate, the inferior turbinate flap alone can be a useful option for reconstruction.

AI upscaling Supporting Image Alignment in Photogrammetric Reconstruction

Abstract. This research aims to investigate and analyze the contribution provided by preventive image processing using AI in the SfM data acquisition process. Specifically, the objective is to observe qualities and defects of "AI upscaling" integrated into the normal workflow of digital restitution, with the hypothesis that greater sharpness and resolution can lead to better alignments and better model generations. Other similar experiments have been carried out previously on the AI intervention in the photos to improve the alignments, but a generic procedure and with untrained public AI has not yet been experimented. In the first phase of the research, the most suitable AI upscaling method for the purpose is selected, processing example images and comparing them with the original and various settings of the AI parameters to maintain likeness. In the second phase, the procedure efficiency was evaluated in several ways: through the automatic evaluation of Agisoft Metashape's Image Quality, by directly comparing the resulting model with the standard digital reconstruction of the same objects, comparing with a model produced with the native AI upscaling of the return program, and finally comparing with a high-level survey without defects. This test was repeated for four case studies specifically diversified by several factors, including subject scale, level of detail, lighting, color, blur, and type of camera used. Clear improvements emerge in all cases of AI upscaling, even reaching successful reconstructions that would not have started with the canonical method. It can therefore be stated that this preventive upscaling procedure is decisive in cases of low quality or damaged datasets, while in cases of already qualitatively sufficient photos it can be a useful support for increasing the level of detail.

Preservation of the MMPH and Status of the Notch Configurations Are Important Factors for Successful Revision ACL Reconstruction.

The aim of this study was to identify the differences in anatomical factors between the patients who underwent revision and primary anterior cruciate ligament reconstructions (ACLR) and compare the outcomes between the 2 surgeries. Retrospective cohort study. Single institution tertiary academic center between 2014 and 2020. A total of 84 matched patients who underwent revision (group I) or primary ACLR (group II). Radiological evaluations were performed using side-to-side differences (SS-D), femorotibial angle, and posterior tibial slope. The medial meniscus posterior horn status as width (MMPHW), medial tibial plateau width (MTPW), notch configurations, tunnel positions, and sagittal graft angle were measured using 3D-CT and magnetic resonance imaging (MRI). Graft signals were assessed using MRI. The clinical outcomes were assessed. Group I showed larger SS-D and higher mean Howell grade of anterior cruciate ligament (ACL) graft than group II (P = 0.002 and P = 0.004, respectively). Multivariate regression analyses showed that the decreased MMPHW/MTPW ratio (P = 0.010) and notch width index (P < 0.007) were significantly independent factors associated with the higher Howell grade of ACL grafts. The decreased MMPHW/MTPW ratio (P < 0.001) was a significantly independent factor associated with larger SS-D. In the subgroup analysis, all patients in the notchplasty group showed wider notches postoperatively (P < 0.001). Revision ACLRs resulted in worse ACL signal intensity and stability outcome. The results of this study suggest that it may be important to preserve the MMPHW as much as possible and check notch configurations, especially during a revision ACLR.

Spatio-temporal reconstruction of droplet impingement dynamics by means of color-coded glare points and deep learning

Abstract The present work introduces a deep learning approach for the three-dimensional reconstruction of the spatio-temporal dynamics of the gas-liquid interface on the basis of monocular images obtained via optical measurement techniques.&amp;#xD;The method is tested an evaluated at the example of liquid droplets impacting on structured solid substrates.&amp;#xD;The droplet dynamics are captured through high-speed imaging in an extended shadowgraphy setup with additional glare points from lateral light sources that encode further three-dimensional information of the gas-liquid interface in the images.&amp;#xD;A neural network is trained for the physically correct reconstruction of the droplet dynamics on a labelled dataset generated by synthetic image rendering on the basis of gas-liquid interface shapes obtained from direct numerical simulation.&amp;#xD;The employment of synthetic image rendering allows for the efficient generation of training data and circumvents the introduction of errors resulting from the inherent discrepancy of the droplet shapes between experiment and simulation. &amp;#xD;The accurate reconstruction of the three-dimensional shape of the gas-liquid interface during droplet impingement on the basis of images obtained in the experiment demonstrates the practicality of the presented approach.&amp;#xD;The introduction of glare points from lateral light sources in the experiments is shown to improve the reconstruction accuracy, which indicates that the neural network learns to leverage the additional three-dimensional information encoded in the images for a more accurate depth estimation.&amp;#xD;By the successful reconstruction of obscured areas in the input images, it is demonstrated that the neural network has the capability to learn a physically correct interpolation of missing data from the numerical simulation.&amp;#xD;Furthermore, the physically reasonable reconstruction of unknown gas-liquid interface shapes for drop impact regimes that were not contained in the training dataset indicates that the neural network learned a versatile model of the involved two-phase flow phenomena during droplet impingement.

Breast reconstruction using the superficial circumflex iliac artery superficial branch perforator (SCISP) flap.

The deep inferior epigastric perforator (DIEP) flap is the gold standard for autologous breast reconstruction. One downside is its risk of postsurgical herniation and bulging due to the opening of the rectus fascia and intramuscular dissection of the rectus abdominis muscle. Additionally this part of the surgery is very time consuming. While the superficial inferior epigastric artery perforator (SIEA) flap has been thoroughly described for total autologous breast reconstruction, the use of the superficial circumflex iliac artery perforator flap in this field is limited. This series introduces the use of an extended superficial circumflex iliac artery (SCIA) perforator flap nourished solely by perforators of the superficial branch of the SCIA- artery for total autologous breast reconstruction.Superficial preparation over the abdominal wall was performed without incising the rectus fascia, dissecting the superficial branch of the SCIA and its accompanying veins and the superficial inferior epigastric vein for additional venous drainage.Four patients underwent successful autologous breast reconstruction with this extended SCIP (superficial circumflex iliac artery perforator)-flap-variation. The term superficial circumflex iliac artery superficial branch perforator (SCISP) flap was introduced to standardize the surgical technique for using only perforators of the superficial branch of the SCIA as free flaps.The SCISP flap is safe and viable for total autologous breast reconstruction, particularly for women with small to medium sized breasts and with superficial dominance of the abdominal vascular system.

Transcarotid flow reversal for proximal control during cerebral aneurysm clip reconstruction: illustrative case.

Paraclinoid aneurysms can pose an operative challenge during clip reconstruction, given the complex surrounding anatomy and the aneurysmal tendency to maintain turgor despite standard approaches to proximal control. This report demonstrates the use of intraoperative retrograde arteriovenous shunting with the transcarotid artery revascularization (TCAR) system to assist in the safe clip reconstruction of an irregular paraclinoid aneurysm. A 33-year-old woman presented with perimesencephalic subarachnoid hemorrhage and was found to have an incidental 9-mm ophthalmic aneurysm. Coil embolization was not successful. During microsurgical clip reconstruction, the left common carotid artery was exposed to allow for proximal control as well as transcarotid arterial sheath placement. Flow reversal was instituted throughout the aneurysm dissection and clipping, with a visible softening of the aneurysm. Intraoperative angiography confirming successful clip reconstruction was performed utilizing the TCAR sheath. The case was complicated by the development of cerebrospinal fluid rhinorrhea postoperatively, requiring surgical repair. The patient has since made a complete recovery. Transcarotid flow reversal utilizing the TCAR system has potential for use in the surgical treatment of paraclinoid aneurysms, as it may aid in softening the aneurysm for safer dissection and clip reconstruction, protect against aneurysm-associated emboli, and provide an avenue for intraoperative angiography. https://thejns.org/doi/10.3171/CASE24330.

Multi-channel photonic sampled ADC with hybrid deep-learning for distortion recovery

Analog-to-digital converter (ADC) is indispensable components in modern information systems, and photonic technologies have emerged as promising avenues for overcoming bottlenecks in ADC performance. This paper introduces a novel approach: a photonic sampled ADC integrated with a neural network that combines Convolutional Neural Networks (CNNs) and Transformers for data recovery. The proposed system utilizes a multi-wavelength optical sampling pulse train interleaved in the time domain through fiber dispersion. Sampled signals are quantified in parallel channels by electronic ADC (EADC). Through supervised training, the hybrid deep neural network extracts both local and global features of photonic system defects, enabling the recovery of distorted data. Experimental validation showcases the effectiveness of this architecture, achieving successful reconstruction of radio frequency (RF) signals at a sampling rate of 12 Giga-samples per second (Gs/s) with an effective number of bits (ENOB) of 7.13. The results underscore the potential of the proposed architecture in achieving high conversion accuracy in multi-channel photonic sampled ADCs.

Gastric conduit reconstruction after esophagectomy.

A high risk of complications still accompanies gastric conduit reconstruction after esophagectomy. In this narrative review, we summarize the technological progress and the problems of gastric conduit reconstruction after esophagectomy. Several types of gastric conduits exist, including the whole stomach and the narrow gastric tube. The clinical outcomes are similar between the two types of conduits. Sufficient blood supply to the conduit is mandatory for a successful esophageal reconstruction. Recently, due to the availability of equipment and its convenience, indocyanine green angiography has been rapidly spreading. When the blood perfusion of the planning anastomotic site is insufficient, several techniques, such as the Kocher maneuver, pedunculated gastric tube with duodenal transection, and additional microvascular anastomosis, exist to decrease the risk of anastomotic failure. There are two different anastomotic sites, cervical and thoracic, and mainly two reconstructive routes, retrosternal and posterior mediastinal routes. Meta-analyses showed no significant difference in outcomes between the anastomotic sites as well as the reconstructive routes. Anastomotic techniques include hand-sewn, circular, and linear stapling. Anastomoses using linear stapling is advantageous in decreasing anastomosis-related complications. Arteriosclerosis and poorly controlled diabetes are the risk factors for anastomotic leakage, while a narrow upper mediastinal space and a damaged stomach predict leakage. Although standardization among the institutional team members is essential to decrease anastomotic complications, surgeons should learn several technical options for predictable or unpredictable intraoperative situations.

Determining the critical factors for realising successful post-disaster reconstruction projects in the Caribbean

Business as usual project management practice may not be applicable in the recovery of the built environment following a disaster. Unfortunately, little research has been undertaken to understand the nature of post-disaster recovery projects and the requirements for their success in the Caribbean. The Caribbean islands' exposure and susceptibility to natural hazards make it essential to understand what constitutes successful post-disaster reconstruction. By drawing on end-users’ perspectives in four Caribbean islands (Antigua, Dominica, Grenada, St. Vincent) through a quantitative survey and factor analysis, this paper identifies critical factors that determine successful outcomes with post-disaster Caribbean recovery projects. The factor analysis results from the survey responses on 24 empirical success factors suggests four composite Caribbean specific critical success factors, namely, 1) effective management of project knowledge, 2) environment and ecosystem stewardship, 3) stakeholder engagements at multiple levels, and 4) efficient management of financial, social and human resources. The findings from this research can assist with minimising the recurring post-disaster reconstruction projects, project financing donors and managers with an understanding of the issues that matter most to the region success, and realising the end-users’ (the beneficiaries) expectations. Mainstreaming these factors into project planning and execution, and adopting resilience-oriented project management practices, augers well for managing Caribbean disaster reconstruction projects for greater success.

Virtual Reality Surgical Planning of a Complex Two-Jaw Defect

Head and neck reconstruction poses challenges requiring stable coverage and optimal appearance and functionality. In complex cases, and beyond the right choice of flap, Virtual Reality (VR) surgical software and preoperative planning, are needed to optimize outcomes. Our patient is a 16-year-old with a history of rhabdomyosarcoma necessitating maxillary-mandibular defect reconstruction. VR-based preoperative planning facilitated the intervention by creating 3D-VR models of facial anatomy and fibula, simulating resection margins, and creating surgical guides for intraoperative use. Our 2-team surgeons opted for a single-staged reconstruction using a vascularized fibula free flap. This case demonstrates successful single-flap reconstruction of a maxillary-mandibular defect, addressing challenges of recipient vessel scarcity, fibrotic scarring, and poor tissue quality. It also underscores the efficacy of a 2-team approach and VR-based preoperative planning in achieving successful outcomes in complex maxillary-mandibular reconstruction. The use of a single fibula flap minimized possible complications and operative time, and the 2-team approach helped by combining the expertise and training of craniofacial and microsurgical trained surgeons. Acknowledging limitations in imaging quality and real-time adaptability, we advocate for continued exploration of VR technologies in enhancing surgical precision in challenging cases.

Reconstruction of Extensive Scalp and Skull Defects with Dural Exposure: Report of a Series of Cases and Literature Review.

Large scalp and calvarial defects pose significant challenges for reconstruction. Successful reconstruction necessitates soft tissue restoration capable of withstanding radiation following tumor resection. Free flaps allow preserving and maintaining the structural and functional status of the reconstructed area. This article presents our experience with microsurgical free tissue transfer for scalp and calvarial defects as well as a literature review on the subject. A retrospective study was conducted to retrieve the files of all the extensive scalp/forehead defects with dural exposure treated in the plastic surgery department of Hotel Dieu de France University Hospital from September 2006 to December 2023. Twelve free tissue transfers were performed in 11 patients between 2006 and 2023. In 3 cases, a 2-stage procedure was performed with the transfer of the free flap in the first stage and the ablative surgery in the second stage 1 week later. A muscular latissimus dorsi flap was used in 9 cases. In 3 patients, the defect involved the forehead and required cutaneous flaps: 2 radial forearm flaps and 1 parascapular flap. Complications included 1 flap venous thrombosis, 2 hematomas, 1 subdural hematoma, and 2 cases of distal flap necrosis. Free tissue transfer is indispensable for addressing large defects of the scalp and calvaria. A 2-stage operation is warranted for debilitated patients with a high risk of complications. The latissimus dorsi muscle flap is the flap of choice to cover extensive defects. Delayed cranioplasty is preferable in contaminated wounds.

Delayed Maxillary Reconstruction with Free Osteocutaneous Fibula Flap Using CAD-CAM Technology

Abstract Background Maxillary reconstruction poses unique challenges for the reconstructive surgeon because of the complex three-dimensional (3D) anatomy of the maxilla. Undertaking this endeavor on secondary reconstruction makes it more difficult due to problems in recreating the true defect. This study is an attempt to demonstrate the role of virtual surgical planning (VSP), 3D printing, and mock surgery in reconstructing such defects using free fibula flaps. Materials and Methods This was a prospective study involving 10 patients of maxillary defects who underwent delayed reconstruction with a free fibula flap. The planning was done preoperatively using computer-aided design and computer-aided manufacturing (CAD-CAM) technology. A mock surgery with 3D printed models was done before the surgery. After the surgery, the accuracy results were obtained by overlapping and measuring fixed point distances between preoperative virtual planning and postoperative computed tomography (CT) scan data. Results and Discussion Nine patients underwent successful reconstruction and were satisfied with the outcome. One patient had flap loss. The mean shift along the horizontal, vertical, and 3D axes was less than 5 mm between the preoperative virtual planning and postoperative CT scan data, indicating accurate reconstruction. We also suggest strategies for soft-tissue and bony inset including inferolateral pedicle origin, anteriorly facing lateral fibular surface, and two bony struts for the alveolus. Conclusion VSP and CAD-CAM technology in maxillary reconstructions help achieve an anatomically accurate neo-maxilla. The addition of mock surgery to the routine and the use of cutting guide avoid unpredictability and reduce the need for adaptation activities on the operating table. CAD-CAM technology despite its limitations is invaluable in maxillary reconstruction and is an important tool for a reconstructive plastic surgeon.

Guidance for Circumflex Scapular Artery Flap Utilization in Pediatric Reconstruction.

The circumflex scapular artery (CSA) flap system, consisting of scapular, parascapular, and chimeric flaps, is useful for pediatric reconstruction in many anatomical locations. The objectives of this case series are to offer insights into our decision-making process for selecting the CSA flap in particular pediatric reconstructive cases and to establish a framework for choosing a scapular or parascapular skin paddle. We also aim to emphasize important technical considerations of CSA flap utilization in pediatric patients. Pediatric reconstruction with CSA flaps performed at our institution between 2006-2022 was retrospectively reviewed. Patient demographics, indications, flap characteristics, complications, and operative data were abstracted. Functional donor site morbidity was assessed through postoperative physical examinations. Unpaired t test analyzed scapular versus parascapular flap size. Eleven CSA flaps were successfully performed in 10 patients (6 scapular and 5 parascapular flaps). Patient ages ranged from 2 to 17 years. Scapular fasciocutaneous free flaps (n = 4) were performed in patients' ages 2-5 years for hand and forearm scar contractures. Two pedicled scapular flaps were performed for a single patient for bilateral axillary hidradenitis suppurativa. The 5 parascapular flaps were performed in patients' ages 2-14 years for calcaneus and forearm avulsion wounds and reconstruction after resection of hidradenitis suppurativa, nevus sebaceous, and Ewing sarcoma. In the sarcoma resection case, a chimeric flap with latissimus dorsi was employed. Average flap size was 101.6 ± 87.3 cm2 (range: 18-300 cm2). Parascapular flaps were significantly larger than scapular flaps (156.60 ± 105.84 cm2 vs 55.83 ± 26.97 cm2, P = 0.0495). Overall, 3 complications occurred (27.3% of cases) including venous congestion (n = 2) and wound dehiscence (n = 1). There were no reported cases of compromised shoulder function at 1.9 ± 2.5-year follow-up. The successful reconstruction rate for scapular, parascapular, and chimeric flaps was 100%. The CSA flap treated a wide variety of indications demonstrating the flap's attributes: large vessel caliber, wide arc of rotation, reliable vascular anatomy, minimal donor site morbidity, and ability to incorporate bone and muscle. Our cases also highlight important pediatric considerations such as vascular mismatch and limited scapular bone stock. We recommend selection of the parascapular over the scapular flap with reconstruction of larger, complex defects given its ability to be harvested with a large skin paddle.

Imaging Spectropolarimeter Using a Multifunctional Metasurface.

Spectral polarization imaging is critical for broad applications ranging from remote sensing to biomedicine. Here, we propose and experimentally demonstrate an imaging spectropolarimeter based on a single multifunctional metasurface. The designed metasurface accurately maps spectral and polarization information onto focal points and vortex beams, enabling simultaneous detection through intensity distributions. More specifically, spectral detection is achieved by determining the azimuthal angle of the strongest focal point, while polarization detection is accomplished by synthesizing the intensity of focal points and the interference pattern of output vortex beams. Experimental results indicate the successful reconstruction for six discrete wavelengths, with the average relative polarization error ranging from 7.85% to 13%. Additionally, the metasurface exhibits excellent imaging and edge detection capabilities owing to the focusing properties and the generation of vortex beams, achieving an imaging resolution of up to 1.4-fold wavelength and offering a new solution for a wide range of applications.

Surgical Treatment of Superior Vena Cava Syndrome in a Preterm Neonate.

Superior vena cava syndrome is rare and challenging clinical entity in neonates. Medical treatment options are usually effective. However, when failed, surgery is warranted. Herein, we present a preterm neonate with SVC syndrome and associated chylothorax. When 2weeks old, he underwent successful open thrombectomy and SVC reconstruction under cardiopulmonary bypass. Immediately after the operation findings of SVC syndrome and chylotorax were completely resolved. To our knowledge, this patient is the smallest baby underwent open SVC reconstruction with cardiopulmonary bypass.

Reconstructing hyperspectral images of textiles from a single RGB image utilizing the multihead self-attention mechanism

Hyperspectral images possess abundant information and play a pivotal role in enhancing the accuracy of color difference detection in textiles. However, traditional hyperspectral imaging methods necessitate costly equipment and intricate operational procedures. A novel deep learning model based on a multihead attention mechanism was proposed in this article to facilitate the extensive application of hyperspectral imaging technology in textile quality inspection. This model enabled the reconstruction of the hyperspectral information of plain weave textiles from a single RGB image. In this model, encoder-decoder architecture and pyramid pooling convolutional operations were employed to integrate multiscale features of plain weave cotton-linen textiles. This could capture details and contextual information in textile images more precisely, enhancing the accuracy of hyperspectral image reconstruction. Simultaneously, an attention mechanism was introduced to increase the model’s receptive field and improve its focus on key regions in the input image and feature maps. This resulted in a reduced weighting of redundant information during network learning, leading to an improved feature extraction capability of the network. Through these methods, successful reconstructions of plain weave textiles hyperspectral information from a single RGB image was achieved. Quantitative and qualitative tests were conducted on two datasets, namely, the NTIRE 2020 dataset and a self-made textile dataset, to evaluate the performance of the proposed method. The approach proposed in this article exhibited promising results on both datasets. Specifically, the reconstructed textile hyperspectral images achieved a root mean square error of 0.0344, a peak signal-to-noise ratio of 29.945, a spectral angle mapper of 3.753, and a structural similarity index measure of 0.955 on the textile dataset. In the reconstructed hyperspectral colorimetric experiment, the maximum value of average color difference was 2.641. These results demonstrate that the method can meet the requirements for textile color measurement applications.

A retrospective, single-center 4-year review of synthetic polyurethane matrix use in burns and other complex wounds

Here we describe the use of a synthetic polyurethane matrix in the setting of burns and other complex wounds in the largest United States case series to date. A retrospective review was conducted at a verified, regional burn center. All patients greater than 18 years of age who received this matrix between January 2019 and July 2023 were included. A total of 182 patients with 250 wounds were included in this study. Thirty-seven percent were smokers, 23.6 % had diabetes and 5.5 % had peripheral vascular disease. The majority were acute burn wounds (60 %), followed by trauma (24.4 %), chronic wounds (5.6 %), infection (4 %) and donor sites (2 %). Exposed structures included fat (54 %), muscle (30 %), bone (16 %) and tendon (14.4 %). Microbial colonization was present in 143 (57.2 %) of cases: 98 (39.2 %) pre-application and 89 (35.6 %) post application. The incidence of new microbial colonisation post-application was 25.6 %. Infection was present in 117 (46.8 %) cases, 49 (19.6 %) pre-matrix application, 44 (17.6 %) post-matrix application and 24 (9.6 %) pre and post application. Eighteen patients (10 %) died. Median length of stay was 27 days. Median time to matrix implantation was 10 days. Median time from matrix placement to skin grafting was 35 days. Where documented, there were 162 wounds (83.5 %) with > 95 % matrix survival and 136 wounds (82.4 %) with > 95 % skin graft survival even in the setting of adverse factors such as infection, diabetes, or nicotine use. This study demonstrates the robustness of this skin substitute to achieve successful reconstruction even in the setting of adverse patient or wound characteristics.

Can machine learning reduce the number of anode readouts for reconstruction of coincident single photons in CDIR resistive sea photon detectors?

This study focuses on exploring the potential of Charge Division Imaging Readout (CDIR) for micro-Channel plate (MCP) based resistive sea photon detectors. The CDIR technique spreads the MCP charge footprint capacitively between readout nodes forming anode segments. Charge measurements at each node are then used to reconstruct incident photon’s position and time. A primary objective is to investigate the minimum number of anode segmentation’s necessary, to allow successful reconstruction of multiple photons within a given time interval where pile up would be an issue for traditional approaches. Allowing for optimisation of the anode structure, investigating for a readout schematic to improve timing, rate capability, and reduce distortion effects.Algorithmic and machine learning (ML) techniques will be compared and utilised to reconstruct spatial positions of multiple photons. The comparison will aim to determine if machine learning techniques can be utilised to correct for algorithmic systematic errors to provide a more robust system, whilst removing the need for complex calibrations and allowing for efficient implementation on FPGA in future work.

Assessing the Viability of Polycaprolactone Mesh in Bilateral Orbital Floor Reconstruction: Insights From Le Fort II Fracture Cases.

This study aims to evaluate the effectiveness of pure polycaprolactone (PCL) mesh in reconstructing complex bilateral orbital floor fractures associated with Le Fort II fractures. PCL mesh is traditionally viewed as less suitable for severe fractures due to its perceived weakness. This study challenges that perception by demonstrating the utility of PCL mesh in high-severity cases. Two patients with Le Fort II fractures and bilateral orbital floor fractures underwent orbital reconstruction using a 3D-printed PCL mesh. The mesh was molded and inserted through subciliary or transconjunctival incisions. Orbital volumes were analyzed preoperatively and postoperatively using CT scans and a 3D Analysis program. Both cases demonstrated significant correction of orbital volume differences postoperatively, leading to improved symmetry and successful reconstruction. For case 1, the preoperative orbital volume difference of 3.2cc was reduced to 1.1cc postoperatively. For case 2, the preoperative orbital volume difference of 1.18cc was reduced to 0.4cc postoperatively. The PCL mesh provided adequate structural support and facilitated effective tissue integration. Despite the radiolucency of the PCL mesh on CT scans, volumetric analysis confirmed stable and balanced orbital volumes. Pure PCL mesh is a viable alternative for orbital floor reconstruction in severe craniofacial fractures, offering a balance of structural support and biocompatibility. To validate these findings, further research with larger samples and long-term follow-up is recommended.

Activating UCHL1 through the CRISPR activation system promotes cartilage differentiation mediated by HIF-1α/SOX9.

Developing strategies to enhance cartilage differentiation in mesenchymal stem cells and preserve the extracellular matrix is crucial for successful cartilage tissue reconstruction. Hypoxia-inducible factor-1α (HIF-1α) plays a pivotal role in maintaining the extracellular matrix and chondrocyte phenotype, thus serving as a key regulator in chondral tissue engineering strategies. Recent studies have shown that Ubiquitin C-terminal hydrolase L1 (UCHL1) is involved in the deubiquitylation of HIF-1α. However, the regulatory role of UCHL1 in chondrogenic differentiation has not been investigated. In the present study, we initially validated the promotive effect of UCHL1 expression on chondrogenesis in adipose-derived stem cells (ADSCs). Subsequently, a hybrid baculovirus system was designed and employed to utilize three CRISPR activation (CRISPRa) systems, employing dead Cas9 (dCas9) from three distinct bacterial sources to target UCHL1. Then UCHL1 and HIF-1α inhibitor and siRNA targeting SRY-box transcription factor 9 (SOX9) were used to block UCHL1, HIF-1α and SOX9, respectively. Cartilage differentiation and chondrogenesis were measured by qRT-PCR, immunofluorescence and histological staining. We observed that the CRISPRa system derived from Staphylococcus aureus exhibited superior efficiency in activating UCHL1 compared to the commonly used the CRISPRa system derived from Streptococcus pyogenes. Furthermore, the duration of activation was extended by utilizing the Cre/loxP-based hybrid baculovirus. Moreover, our findings show that UCHL1 enhances SOX9 expression by regulating the stability and localization of HIF-1α, which promotes cartilage production in ADSCs. These findings suggest that activating UCHL1 using the CRISPRa system holds significant potential for applications in cartilage regeneration.