Tissue Bridge Research Articles

Corticospinal Tract Sparing in Cervical Spinal Cord Injury.

Disruptions in the brain's connections to the hands resulting from a cervical spinal cord injury (cSCI) can lead to severe and persistent functional impairments. The integrity of these connections is an important predictor of upper extremity recovery in stroke and may similarly act as a biomarker in cSCI. In this perspective article, we review recent findings from a large cohort of individuals with cSCI, demonstrating the predictive value of corticospinal tract (CST) integrity in cSCI-CST sparing. This research underscores that, akin to stroke, the integrity of brain-to-hand connections is crucial for predicting upper extremity recovery following cSCI. We address the limitations of commonly used metrics, such as sacral sparing and the concept of central cord syndrome. Furthermore, we offer insights on emerging metrics, such as tissue bridges, emphasizing their potential in assessing the integrity of brain connections to the spinal cord.

Extent of Traumatic Spinal Cord Injury Is Lesion Level Dependent and Predictive of Recovery: A Multicenter Neuroimaging Study.

Assessing the extent of the intramedullary lesion after spinal cord injury (SCI) might help to improve prognostication. However, because the neurological level of injury impacts the recovery potential of SCI patients, the question arises whether lesion size parameters and predictive models based on those parameters are affected as well. In this retrospective observational study, the extent of the intramedullary lesion between individuals who sustained cervical and thoracolumbar SCI was compared, and its relation to clinical recovery was assessed. In total, 154 patients with subacute SCI (89 individuals with cervical lesions and 65 individuals with thoracolumbar lesions) underwent conventional clinical magnetic resonance imaging 1 month after injury and clinical examination at 1 and 12 months. The morphology of the focal lesion within the spinal cord was manually assessed on the midsagittal slice of T2-weighted magnetic resonance images and compared between cervical and thoracolumbar SCI patients, as well as between patients who improved at least one American Spinal Injury Association Impairment Scale (AIS) grade (converters) and patients without AIS grade improvement (nonconverters). The predictive value of lesion parameters including lesion length, lesion width, and preserved tissue bridges for predicting AIS grade conversion was assessed using regression models (conditional inference tree analysis). Lesion length was two times longer in thoracolumbar compared with cervical SCI patients (F = 39.48, p < 0.0001), whereas lesion width and tissue bridges width did not differ. When comparing AIS grade converters and nonconverters, converters showed a smaller lesion length (F = 5.46, p = 0.021), a smaller lesion width (F = 13.75, p = 0.0003), and greater tissue bridges (F = 12.87, p = 0.0005). Using regression models, tissue bridges allowed more refined subgrouping of patients in AIS groups B, C, and D according to individual recovery profiles between 1 month and 12 months after SCI, whereas lesion length added no additional information for further subgrouping. This study characterizes differences in the anteroposterior and craniocaudal lesion extents after SCI. The two times greater lesion length in thoracolumbar compared with cervical SCI might be related to differences in the anatomy, biomechanics, and perfusion between the cervical and thoracic spines. Preserved tissue bridges were less influenced by the lesion level while closely related to the clinical impairment. These results highlight the robustness and utility of tissue bridges as a neuroimaging biomarker for predicting the clinical outcome after SCI in heterogeneous patient populations and for patient stratification in clinical trials.

Lesion characteristics are associated with bowel, bladder, and overall independence following cervical spinal cord injury

Context/Objective There is a growing global interest in quantifying spinal cord lesions and spared neural tissue using magnetic resonance imaging (MRI) in individuals with spinal cord injury (SCI). The primary objective of this study was to assess the relationships between spinal cord lesion characteristics assessed on MRI and bowel, bladder, and overall independence following SCI. Design Retrospective, exploratory study. Participants 93 individuals with cervical SCI who were enrolled in a local United States Model Systems SCI database from 2010 to 2017. Methods Clinical and MRI data were obtained for potential participants, and MRIs of eligible participants were analyzed. Explanatory variables, captured on MRIs, included intramedullary lesion length (IMLL), midsagittal ventral tissue bridge width (VTBW), midsagittal dorsal tissue bridge width (DTBW), and axial damage ratio (ADR). Outcome Measures Bowel and bladder management scale of the Functional Independence Measure (FIM) and FIM total motor score. Results When accounting for all four variables, only ADR was significantly associated with bowel independence (OR = 0.970, 95% CI: 0.942–0.997, P = 0.030), and both ADR and IMLL were strongly associated with bladder independence (OR = 0.967, 95% CI: 0.936–0.999, P = 0.046 and OR = 0.948, 95% CI: 0.919–0.978, P = 0.0007, respectively). 32% of the variation in overall independence scores were explained by all four predictive variables, but only ADR was significantly associated with overall independence after accounting for all other predictive variables (β = −0.469, 95% CI: −0.719, −0.218, P = 0.0004). Conclusions Our results suggest that the MRI-measured extent of spinal cord lesion may be predictive of bowel, bladder, and overall independence following cervical SCI.

Prognostic value of tissue bridges in cervical spinal cord injury: a longitudinal, multicentre, retrospective cohort study

The accuracy of prognostication in patients with cervical spinal cord injury (SCI) needs to be improved. We aimed to explore the prognostic value of preserved spinal tissue bridges-injury-spared neural tissue adjacent to the lesion-for prediction of sensorimotor recovery in a large, multicentre cohort of people with SCI. For this longitudinal study, we included patients with acute cervical SCI (vertebrae C1-C7) admitted to one of three trauma or rehabilitation centres: Murnau, Germany (March 18, 2010-March 1, 2021); Zurich, Switzerland (May 12, 2002-March 2, 2019); and Denver, CO, USA (Jan 12, 2010-Feb 16, 2017). Patients were clinically assessed at admission (baseline), at discharge (3 months), and at 12 months post SCI. Midsagittal tissue bridges were quantified from T2-weighted images assessed at 3-4 weeks post SCI. Fractional regression and unbiased recursive partitioning models, adjusted for age, sex, centre, and neurological level of injury, were used to assess associations between tissue bridge width and baseline-adjusted total motor score, pinprick score, and light touch scores at 3 months and 12 months. Patients were stratified into subgroups according to whether they showed better or worse predicted recovery. The cohort included 227 patients: 93 patients from Murnau (22 [24%] female); 43 patients from Zurich (four [9%] female); and 91 patients from Denver (14 [15%] female). 136 of these participants (from Murnau and Zurich) were followed up for up to 12 months. At 3 months, per preserved 1 mm of tissue bridge at baseline, patients recovered a mean of 9·3% (SD 0·9) of maximal total motor score (95% CI 7·5-11.2), 8·6% (0·8) of maximal pinprick score (7·0-10·1), and 10·9% (0·8) of maximal light touch score (9·4-12·5). At 12 months post SCI, per preserved 1 mm of tissue bridge at baseline, patients recovered a mean of 10·9% (1·3) of maximal total motor score (8·4-13·4), 5·7% (1·3) of maximal pinprick score (3·3-8·2), and 6·9% (1·4) of maximal light touch score (4·1-9·7). Partitioning models identified a tissue bridge cutoff width of 2·0 mm to be indicative of higher or lower 3-month total motor, pinprick, and light touch scores, and a cutoff of 4·0 mm to be indicative of higher and lower 12-month scores. Compared with models that contained clinical predictors only, models additionally including tissue bridges had significantly improved prediction accuracy across all three centres. Tissue bridges, measured in the first few weeks after SCI, are associated with short-term and long-term clinical improvement. Thus, tissue bridges could potentially be used to guide rehabilitation decision making and to stratify patients into more homogeneous subgroups of recovery in regenerative and neuroprotective clinical trials. Wings for Life, International Foundation for Research in Paraplegia, EU project Horizon 2020 (NISCI grant), and ERA-NET NEURON.

Enoki‐Inspired Microfibers and Extracellular Matrix Enhance Biaxially Interlocking Interfaces

Taking inspiration from diverse interlocking and adhesion structures found in nature, a biaxially interlocking interface is developed in this work. This interface is formed by interconnecting two electrostatically flocked substrates and its mechanical strength is enhanced through the incorporation of enoki‐mushroom‐shaped microfibers and deposited extracellular matrix (ECM). Tips of flocked straight fibers can be transformed into mushroom shapes through thermal treatment. The tensile strength of interlocked scaffolds with mushroom‐shaped tips drastically increases when compared to scaffolds made of straight fibers, which is not reported previously. More cells proliferate within interlocked scaffolds with mushroom‐shaped tips than scaffolds with straight fibers. Additionally, the mechanical strength (e.g., compressive, tensile, and shear) of cell‐seeded interlocked scaffolds increases proportionally to the amount of ECM deposited by dermal fibroblasts. The biaxially interlocking interface developed in this study holds promise for applications in engineering interfacial tissues, modeling tissue interfaces, investigating tissue–tissue interactions, and facilitating tissue bridging or binding.

Wallerian Degeneration Assessed by Multi-Modal Magnetic Resonance Imaging of Cervical Spinal Cord Is Associated With Neurological Impairment After Spinal Cord Injury.

While Wallerian degeneration (WD) is a crucial pathological process induced with spinal cord injury (SCI), its underlying mechanisms is still understudied. In this study, we aim to assess structural alterations and clinical significance of WD in the cervical cord following SCI using multi-modal magnetic resonance imaging (MRI), which combines T2*-weighted imaging and diffusion tensor imaging (DTI). T2*-weighted images allow segmentation of anatomical structures and the detection of WD on macrostructural level. DTI, on the other hand, can identify the reduction in neuroaxonal integrity by measuring the diffusion of water molecules on the microstructural level. In this prospective study, 35 SCI patients (19 paraplegic and 16 tetraplegic patients) and 12 healthy controls were recruited between July 2020 and May 2022. The hyperintensity voxels in the dorsal column was manually labeled as WD on T2*-weighted images. The mean cross-sectional area (CSA) and mean DTI indexes of WD at the C2 level were calculated and compared between groups. Correlation analysis was used to determine the associations of the magnitude of WD with lesion characteristics and clinical outcomes. Compared with controls, SCI patients showed evident hyperintensity (35/35) and decreased neuroaxonal integrity (p < 0.05) within the dorsal column at the C2 level. A higher neurological level of injury was associated with a larger mean CSA and reduction in neuroaxonal integrity within WD (p < 0.05). Smaller total and dorsal tissue bridges were related to greater mean CSA and lower fractional anisotropy values in WD (p < 0.05), respectively. Moreover, SCI participants with significantly larger CSAs and significantly lower microstructural integrity had worse sensory outcomes (p < 0.05). This comprehensive evaluation of WD can help us better understand the mechanisms of WD, monitor progression, and assess the effectiveness of therapeutic interventions after SCI.

Midsagittal Tissue Bridges and Walking Recovery in Spinal Cord Injury

Midsagittal Tissue Bridges and Walking Recovery in Spinal Cord Injury

Longitudinal motor system changes from acute to chronic spinal cord injury.

In acute spinal cord injury (SCI), magnetic resonance imaging (MRI) reveals tissue bridges and neurodegeneration for 2 years. This 5-year study aims to track initial lesion changes, subsequent neurodegeneration, and their impact on recovery. This prospective longitudinal study enrolled acute SCI patients and healthy controls who were assessed clinically-and by MRI-regularly from 3 days postinjury up to 60 months. We employed histologically cross-validated quantitative MRI sequences sensitive to volume, myelin, and iron changes, thereby reflecting indirectly processes of neurodegeneration and neuroinflammation. General linear models tracked lesion and remote changes in volume, myelin- and iron-sensitive magnetic resonance indices over 5 years. Associations between lesion, degeneration, and recovery (using the Spinal Cord Independence Measure [SCIM] questionnaire and the International Standards for Neurological Classification of Spinal Cord Injury total motor score) were assessed. Patients' motor scores improved by an average of 12.86 (95% confidence interval [CI] = 6.70-19.00) points, and SCIM by 26.08 (95% CI = 17.00-35.20) points. Within 3-28 days post-SCI, lesion size decreased by more than two-thirds (3 days: 302.52 ± 185.80 mm2 , 28 days: 76.77 ± 88.62 mm2 ), revealing tissue bridges. Cervical cord and corticospinal tract volumes transiently increased in SCI patients by 5% and 3%, respectively, accompanied by cervical myelin decreases and iron increases. Over time, progressive atrophy was observed in both regions, which was linked to early lesion dynamics. Tissue bridges, reduced swelling, and myelin content decreases were predictive of long-term motor score recovery and improved SCIM score. Studying acute changes and their impact on longer follow-up provides insights into SCI trajectory, highlighting the importance of acute intervention while indicating the potential to influence outcomes in the later stages.

EVALUATION OF A CALCIUM PHOSPHATE-COLLAGEN MATRIX BONE GRAFT WITH NEEDLE-SHAPED SUBMICRON SURFACE TOPOGRAPHY IN A CLINICALLY RELEVANT SHEEP POSTEROLATERAL LUMBAR SPINE FUSION MODEL

Biphasic calcium phosphate (BCP) with a characteristic needle-shaped submicron surface topography (MagnetOs) has attracted much attention due to its unique bone-forming ability which is essential for repairing critical-size bone defects such as those found in the posterolateral spine. Previous in vitro and ex-vivo data performed by van Dijk LA and Yuan H demonstrated that these specific surface characteristics drive a favorable response from the innate immune system.This study aimed to evaluate and compare the in vivo performance of three commercially-available synthetic bone grafts, (1) i-FACTOR Putty®, (2) OssDsign® Catalyst Putty and (3) FIBERGRAFT® BG Matrix, with that of a novel synthetic bone graft in a clinically-relevant instrumented sheep posterolateral lumbar spine fusion (PLF) model. The novel synthetic bone graft comprised of BCP granules with a needle-shaped submicron surface topography (MagnetOs) embedded in a highly porous and fibrillar collagen matrix (MagnetOs Flex Matrix).Four synthetic bone grafts were implanted as standalone in an instrumented sheep PLF model for 12 weeks (n=3 bilateral levels per group; levels L2/3 &amp; L4/5), after which spinal fusion was determined by manual palpation, radiograph and µCT imaging (based on the Lenke scale), range-of-motion mechanical testing, and histological and histomorphological evaluation.Radiographic fusion assessment determined bilateral robust bone bridging (Lenke scale A) in 3/3 levels for MagnetOs Flex Matrix compared to 1/3 for all other groups. For µCT, bilateral fusion (Lenke scale A) was found in 2/3 levels for MagnetOs Flex Matrix, compared to 0/3 for i-FACTOR Putty®, 1/3 for OssDsign® Catalyst Putty and 0/3 for FIBERGRAFT® BG Matrix. Fusion assessment for MagnetOs Flex Matrix was further substantiated by histology which revealed significant graft resorption complemented by abundant bone tissue and continuous bony bridging between vertebral transverse processes resulting in bilateral spinal fusion in 3/3 implants.These results show that MagnetOs Flex Matrix achieved better fusion rates compared to three commercially-available synthetic bone grafts when used as a standalone in a clinically-relevant instrumented sheep PLF model.

Ligamentum Teres Hepatis Tunnel (Pons hepatis) in Human Liver: A Case Report from Nepal

INTRODUCTION The liver, the biggest gland with diverse metabolic activity consist right and left lobe, where left lobe was isolated from quadrate lobe by umbilical or fissure for ligamentum teres exhibits variation. The case reported explains about the liver tissue bridge, a 2 cm long creating incomplete tunnel that connect the quadrate lobe to the left lobe corresponding to type 4 b variation of Pons hepatis. As a result, the tunnel may depict a deceptive impression of a diseased cavity due to liver parenchyma and confuse surgeons and pathologist.

Intraoperative prevention of postoperative ammetropies by intrastromal ring implantation

The experiment was carried out on 6 isolated donor (cadaver) eyes, penetrating keratoplasty was performed with intrastromal ring implantation according to the proposed method.When modeling the technology we proposed, we obtained patterns identical to those given, we observed a complete cut of the cornea without the formation of tissue bridges and adhesions. The developed new femtosecond laser cutting patterns made it possible to implant the intrastromal ring into the residual corneal stroma of the recipient without the need for additional fixation.

Abstract 18572: Mimickers of Chiari Network in the Left Atrium

Case: 84-year-old female with ischemic cardiomyopathy and severe secondary mitral regurgitation with restricted leaflet mobility due to chordae tethering and a large central regurgitant jet. She underwent trans-catheter edge to edge repair with Mitra Clip NTW. The clip was aligned in the 12 to 6 o'clock position in the middle of A2/P2 scallop and appropriate graft was obtained with good tissue bridging. The trans mitral gradient at the end of the procedure was 3 mmHg and final V-waves at 10 mmHg. After the guiding catheter was moved back to the right atrium, the transesophageal echocardiogram (TEE) showed the presence of an echo dense flickering, bubble-like mobile structure around the right upper pulmonary vein. The heart team agreed that it looked like an endothelial disruption induced by the guiding catheter. After careful consideration and using shared decision making, the patient was maintained on Eliquis for 6 months without evidence of thromboembolic phenomena. Repeat TEE showed a healed dissection flap and no echo dense structure seen previously. Discussion: Unlikely to be thrombus or air bubbles, this structure looked like what we would see in a Chiari network. Complications after Mitra Clip procedure have been well described and can be broadly divided into procedure related and device related. Endothelial disruption with the imaging characteristics shown in this case has not been described. There are no evidence-based guidelines on how to proceed with this type of complication. It is well known that endothelial damage increases the risk for thrombosis and embolic phenomena. Due to concerns of a stroke, the decision was made to start anticoagulation with the plan of redo TEE. This case demonstrates the importance of performing TEE after Mitra Clip procedure to look for lesions that would increase the risk of stroke. It also demonstrates that patients with endothelial disruption after Mitra clip may benefit from short term anticoagulation for stroke prevention.

Biomechanical analysis of tendon regeneration capacity of Iberian ribbed newts following transection injury: Comparison to a mouse model.

Adult mammals are known for their poor ability to regenerate tissues, including tendons. On the other hand, urodeles have become an important model in regenerative studies for their remarkable ability to regenerate various body parts and organs throughout life, such as limbs, retinas, or even the brain. However, little is known about their capacity to regenerate injured tendons. If newts can also repair tendons without scar formation, they may be a suitable animal model for tendon regeneration studies in other adult vertebrates. Therefore, the present study used Iberian ribbed newts to characterize mechanical and structural regeneration of tendons following transection, using tensile tests and multiphoton microscopy. A digital flexor tendon in a hindlimb was transected either partially or completely, and regenerated tendon was examined 6 and 12 weeks after the operation. Tensile strength of regenerated tendons was significantly less than normal at 6 weeks, but was remarkably recovered at 12 weeks, reaching levels comparable to those of uninjured tendons. On the other hand, mouse tendons demonstrated poor recovery of strength even after 12 weeks. Multiphoton microscopy revealed that tendon-like collagenous tissue bridges residual tendon stubs in newts, but disorganized scar-like tissue filled the injured location in mice. These findings highlight the remarkable capacity of newts to recover from tendon injury and confirm the utility of newts as a model to study tendon regeneration.

Antioxidant MnO2 nanozymes-encapsulated hydrogel synergistically regulate the spinal ROS microenvironment and promote spinal cord repair

Traumatic spinal cord injury (SCI) usually leads to neuronal death and axon destruction, resulting in long-term dysfunction, permanent functional impairment, significant caregiving demands, and substantial financial burden. Therefore, a crucial aspect of SCI recovery lies in understanding how to inhibit neural stem cell (NSC) death, regulate the spinal microenvironment and promote the regeneration of neurons and axons. Herein, we designed dopamine (DA)-modified hyaluronic acid (HA) with the bridging of CeCl3 molecules, termed the CHD hydrogel. To confer regenerative properties to the hydrogel, we incorporated metformin (Met) and manganese dioxide (MnO2) to form the MnO2/Met@CHD hydrogel. The MnO2/Met@CHD hydrogel could promote the NSC adhesive growth and nerve tissue bridging, and improve neuronal differentiation and neurite outgrowth in a pathological ROS microenvironment, suggesting its excellent effect against oxidative stress. Furthermore, the MnO2/Met@CHD hydrogel can facilitate the migration and accumulation of nestin+ NSCs and inhibit GFAP+ astrocytic scar formation, thereby providing optimized microenvironments for axonal regeneration. Collectively, the MnO2/Met@CHD hydrogel system shows great promise as a novel approach for the treatment of SCI.

Tension Reduction With Force Modulating Tissue Bridges Reduces Wounds in Breast Surgery.

Tension on healing wounds increases the risk of dehiscence and poor or pathologic scar formation. Force modulating tissue bridges (FMTBs) represent a new class of wound closure and support devices designed to offload tension on healing wounds to improve wound healing and scar outcomes. The study was undertaken to assess the efficacy of FMTBs to reduce the risk of wound healing complications in elective breast surgery. One hundred twenty-two consecutive patients undergoing bilateral aesthetic breast surgery underwent intraoperative placement of FMTBs on the vertical limb closure site. A matched case-control cohort of 121 consecutive patients was established for comparison. Wounds were considered significant if larger than 3 mm in diameter. The primary outcome of breast wounds >3 mm was reported with a relative risk, and all outcomes were framed with number needed to treat. The control and intervention cohorts had similar demographics, comorbidities, type of operation, and incision pattern utilized. Within the FMTB group, 96.7% (n = 118) patients completed treatment per protocol. Significant wounds occurred in 1.7% (n = 2) of patients in the tissue bridge vs 15.2% (n = 19) in controls on a per patient/per protocol basis (89% reduction, P < .001). Statistically significant improvements were maintained on sensitivity analyses with intention to treat, even when minor wounds were included. There were no complications noted related to FMTBs. FMTBs are safe and highly effective at reducing the risk of wound formation in elective breast surgery. Results are consistent with sensitivity analyses based on clinical and methodological factors. Further research will assess long-term scar outcomes.

Spinal cord repair is modulated by the neurogenic factor Hb-egf under direction of a regeneration-associated enhancer

Unlike adult mammals, zebrafish regenerate spinal cord tissue and recover locomotor ability after a paralyzing injury. Here, we find that ependymal cells in zebrafish spinal cords produce the neurogenic factor Hb-egfa upon transection injury. Animals with hb-egfa mutations display defective swim capacity, axon crossing, and tissue bridging after spinal cord transection, associated with disrupted indicators of neuron production. Local recombinant human HB-EGF delivery alters ependymal cell cycling and tissue bridging, enhancing functional regeneration. Epigenetic profiling reveals a tissue regeneration enhancer element (TREE) linked to hb-egfa that directs gene expression in spinal cord injuries. Systemically delivered recombinant AAVs containing this zebrafish TREE target gene expression to crush injuries of neonatal, but not adult, murine spinal cords. Moreover, enhancer-based HB-EGF delivery by AAV administration improves axon densities after crush injury in neonatal cords. Our results identify Hb-egf as a neurogenic factor necessary for innate spinal cord regeneration and suggest strategies to improve spinal cord repair in mammals.

The Role of Machine Learning in Predicting the Onset and Progression of Neuropathic Pain After Spinal Cord Injury: A Literature Review

Introduction: Developing a diagnostic tool that can determine whether a patient will develop neuropathic pain following a spinal cord injury can aid clinicians in treatment procedures and improve patient outcomes. Developing new detection technology can take years, thus finding a way to use existing diagnostic tools would be optimal. Machine learning can be leveraged to incorporate existing data and classify patient outcomes when there are obvious patterns for classification. Methods: A review of full reports published in English was conducted through PubMed. The relevant keywords used in this search included “neuropathic pain”, “spinal cord injury”, machine learning, and “predict” among others. Eight relevant citations were retrieved and reviewed. Results: A decision tree regressor model using clinical measures for neuropathic pain and level of spinal cord injury found that BMI and anxiety scores were the most influential variables in predicting outcomes. A similar tree for functional magnetic resonance imaging (fMRI) data found ventral and dorsal tissue bridges to be predictors of neuropathic pain. Another fMRI study pointed to a strong correlation between changes in perioperative blood oxygen levels at the ipsilateral frontal lobe and neuropathic pain outcomes. Magnetic resonance spectroscopy (MRS) implicated a lower glutamate-glutamine/myoinositol ratio in high neuropathic pain. Various machine learning algorithms were evaluated in building an EEG classifier in two separate studies, and classification accuracies greater than 80% were reached in both. A classifier built using positron emission tomography data attained classification accuracies of 87.5%. Discussion: The most common machine learning algorithm used in building classifiers was support vector machines, linear discriminant analysis and neural net. Regression trees were also used, but they were used to elucidate the variables influencing predictions. Each study has its limitations, either due to limitations of the study method, classification method or data type. Conclusion: There exist many methods to study neuropathic pain and spinal cord injury and each method provides different information regarding the mechanism of pain, influential variables, and physiological changes that occur with pain. Classification can be done using any of these methods to achieve acceptable accuracies, but these accuracies are not enough for a clinical prognostic classifier.

ESEM-EDX Mineralization and Morphological Analysis of Human Retrieved Maxillary Sinus Bone Graft Biopsies before Loading.

This study aimed to analyze the morphology of bone graft granules, the presence of granule demineralization, and bone morphology in retrieved human maxillary sinus bone graft biopsies. Healthy patients underwent sinus bone augmentation using lateral access. Two different dimensions of the antrostomy were performed, a 4 mm or 8 mm height. After 6 months, all sites received one implant using a flap technique, crestal positioning, and submerged healing. Implant biopsies were retrieved after 3 months and were histologically processed. The ESEM analysis was performed on the entire portion of the peri-implant bone (up to 750 µm from the implant thread). Three different regions of interest (ROIs) were selected: the coronal, middle, and apical portions of the implant. In these areas, EDX was performed, and calcium (Ca), phosphate (P), nitrogen (N), and their atomic ratios (Ca/P, Ca/N, and P/N) were calculated. Different bone tissue electron-dense areas were detected through grayscale intensity quantification of ESEM images with different organic (N) or inorganic (Ca,P) compositions. A total of 16 biopsies from 16 healthy patients were analyzed. Bone graft granules were mostly detected in the apical ROI. New bone tissue bridges were detected in the apical and middle ROI. These structures, with lower Ca/N and P/N ratios, were connected and enveloped the bone graft granules. Cortical ROI revealed the most mineralized bone tissue. Conclusions: After 9 months, bone graft resorption was only partially completed and new bone tissue appeared less mineralized in the middle and apical ROI than in the coronal ROI.

Novel arm-width-expandable transcatheter edge-to-edge repair system: Preclinical experiment and first-in-human study.

The ValveClasp system is a novel transcatheter edge-to-edge repair (TEER) device with an arm-width-expandable clip that allows treatment of patients with only one clip more frequently. This study aimed to evaluate the feasibility and safety of a novel TEER device in porcine models and patients. Fourteen young adult pigs were enrolled. A clip with an expanded arm was implanted under epicardial echocardiography and fluoroscopy guidance. Five patients with at least moderate-to-severe mitral regurgitation underwent TEER using the ValveClasp system to test the safety and effectiveness of the device. The device success rate was 100% (14/14) in the animal experiments, and all clips were deployed at the A2P2 segments, forming a double-orifice mitral valve. Gross observations on day 180 showed a wide and continuous tissue bridge between the leaflets. The acute procedural success rate was 100% (5/5). Only one clip was required in all patients, and all achieved effective postoperative endpoints (grade ≤2+). During 30-day follow-up, no adverse events occurred. All patients'vena Contracta width (from 8.04 0.71 mmto 3.84 ± 1.18 mm, p = 0.012), mitral regurgitation area (from 12.75 ± 3.13 cm2 to 3.50 ± 1.66 cm2 , p = 0.008), and left ventricular end diastolic diameter (from 52.00 ± 2.92 mm to 46.00 ± 3.08 mm, p = 0.040) were considerably decreased, without obvious mitral stenosis. The novel arm-width-expandable ValveClasp device is safe for TEER for treating severe mitral regurgitation.

Mucosal adhesion phenomenon after maxillary sinus floor elevation: A preclinical study.

To describe the histological events that occur after maxillary sinus floor elevation when the elevated and undetached sinus mucosa are in close proximity or in contact with each other. From 76 rabbits, 152 elevated maxillary sinuses were analyzed histologically. Sites without adhesions were classified as "No proximity," whereas the adhesion stages were divided into "Proximity," "Fusion," and "Synechia stages." The width of the pseudostratified columnar epithelium and the distance between the two layers of the elevated and undetached sinus mucosae were measured at various standardized positions. Thirty-one sites presenting with adhesions were found. Twelve sites were in the proximity stage," presenting cilia of the two epithelial layers that were shortened and interlinked within the mucous context. Hyperactivity of the goblet cells was also observed. In the other cases, the hyperplastic epithelium showed attempts to reach the contralateral mucosa. The 15 "fusion stage" sites presented regions with epithelial cells of the two mucosal layers that penetrated each other. Four sites presented "synechiae stages," represented by bridges of connective tissue connecting the two lamina propria. Close proximity or tight contact between the elevated and undetached mucosa adhering to the bone walls might occur after maxillary sinus floor elevation. This induced hyperplasia of the epithelial cells and adhesion of the two layers until synechiae formation.