Study of Tissue Damage Induced by Insertion of Composite-Coated Needle.

Medical interventions have significantly progressed in developing minimally invasive techniques like percutaneous procedures. These procedures include biopsy and internal radiation therapy, where a needle or needle-like medical device is inserted through the skin to access a target inside the body. Ensuring accurate needle insertion and minimizing tissue-damage or cracks are critical in these procedures. This research aims to examine the coated needle effect on the force required to insert the needle (i.e., insertion force) and on tissue-damage during needle insertion into the bovine kidney. Reducing the needle insertion force, which is influenced by needle surface friction, generally results in a reduction in tissue-damage. Surgical needles were coated with a composite material, combining Polytetrafluoroethylene, Polydopamine, and Activated Carbon. Force measurement during needle insertion and a histological study to determine tissue-damage were conducted to evaluate the effectiveness of the coating. The insertion force was reduced by 49 % in the case of the coated needles. Furthermore, a histological analysis comparing tissue-damage resulting from coated and uncoated needles revealed an average 39 % reduction in tissue-damage with the use of coated needles. The results of this study demonstrate the potential of coated needles to enhance needle insertion and safety during percutaneous procedures.

Relevance of a bone and joint registry for fracture-related infections.

The UK Bone and Joint Infection Registry (BAJIR) is a national project established in 2018 with the aim of collecting information about demographics, co-morbidities, pathogens, treatment strategies and outcomes on all patients who are diagnosed with, and treated for, a bone or joint infection in the UK with the objective of providing an understanding of the burden of disease. In time these data will be used to inform best practice, direct research and provide information for commissioners of healthcare. In this fracture-related infection special edition article, we discuss the registry's development, relevance and how we see it directing our practice in the future. Equally, we have highlighted some potential limitations and lessons learned.

Microbiological Profile of Fracture Related Infection at a UK Major Trauma Centre.

Fracture Related Infection (FRI) represents one of the biggest challenges for Trauma and Orthopaedic surgery. A better understanding of the microbiological profile should assist with decision-making and optimising outcomes. Our primary aim was to report on the microbiological profile of FRI cases treated over a six-year period at one of Europe's busiest trauma centres. Secondarily, we sought to correlate our findings with existing anti-microbiological protocols and report on diagnostic techniques employed in our practice. All adult cases of FRI treated in our institution between 2016 and 2021 were identified, retrospectively. We recorded patient demographics, diagnostic strategies, causative organisms and antibiotic susceptibilities. There were 330 infection episodes in 294 patients. A total of 463 potentially pathogenic organisms (78 different species) were identified from cultures, of which 57.2% were gram-positive and 39.7% gram-negative. Polymicrobial cultures were found in 33.6% of cases and no causative organism was found in 17.5%. The most prevalent organisms were Staphylococcus aureus (24.4%), coagulase-negative Staphylococci (14%), Pseudomonas aeruginosa (8.2%), Enterobacter species (7.8%) and Escherichia coli (6.9%). Resistant gram-positive organisms (methicillin resistant Staphylococcus aureus or vancomycin-resistant Enterococci) were implicated in 3.3% of infection episodes and resistant gram-negatives (extended-spectrum beta-lactamase, ampC or carbapenemase-producing bacteria) in 13.6%. The organisms cultured in 96.3% of infection episodes would have been covered by our empirical systemic antibiotic choice of teicoplanin and meropenem. To our knowledge, this is the largest reported single-centre cohort of FRIs from a major trauma centre. Our results demonstrate patterns in microbiological profiles that should serve to inform the decision-making process regarding antibiotic choices for both prophylaxis and treatment.

Experimental and analytical study on insertion force of composite-coated needle in soft tissue material.

Medical interventions require control over surgical needle insertion to minimize tissue damage and target inaccuracies during percutaneous procedures. The composite coating of the needle using Polydopamine (PDA), Polytetrafluoroethylene (PTFE), and Activated Carbon (C) has been used to reduce the damaging needle insertion force. This research aims to further understand the interfacial mechanics of coated needle insertion by studying the forces at the needle and tissue interface and developing an analytical insertion force model through a combined experimental and numerical method. The proposed analytical force model is divided into two components: (1) Friction force on the needle shaft, modeled using a modified Karnopp model that includes an elastic force component; (2) Cutting force on the needle tip, modeled using a constant cutting coefficient for a given tissue and insertion speed. In this work, the analytical model was established by incorporating experiments conducted at a reasonable 35 mm insertion depth in tissues. In a bovine kidney with a 35 mm insertion depth, the insertion force evaluated through experimentation and modeling differed by 6.5% for a bare needle and 17.1% for a coated needle. It is important to note that this difference in the analytical insertion force model is anticipated when dealing with real tissues with a highly complex structured tissue. Prediction of the insertion force could potentially be utilized in robotic needle systems for needle control to improve the success of percutaneous procedures.

A major trauma centre experience with gentamicin-coated tibial intramedullary nails (ETN PROtect™) in acute primary open fracture fixation and complex revision surgery.

PURPOSE: Fracture-related infections (FRI) following intramedullary nailing for tibial shaft fractures remain challenging to treat with associated high patient morbidity and health care costs. Recently, antibiotic-coated nails have been introduced as a strategy to reduce implant related infection rates in high-risk patients. We present the largest single-centre case series on ETN PROtect® outcomes reporting on fracture union, infection rates and treatment complications. METHODS: Fifty-six adult patients underwent surgery with ETN PROtect® between 01/09/17 and 31/12/20. Indications consisted of acute open fractures and complex revision cases (previous FRI, non-union surgery and re-fracture) with a mean of three prior surgical interventions. We report on patient demographics, union rates and deep infection. Minimum follow-up was one year. RESULTS: One (1.8%) patient developed a deep surgical infection and associated non-union requiring further surgery. In addition, we identified three cases (5.4%) of aseptic non-union following facture treatment with ETN PROtect®. Of the five patients who underwent staged complex revision surgery for established FRI with ETN PROtect®, all had treatment failure with ongoing symptoms of deep infection requiring implant removal and further treatment. CONCLUSION: Use of the ETN PROtect® nail in high-risk patients (open fractures and those initially treated with external fixation) and in those patients with aseptic non-unions, demonstrates promising outcomes in the prevention of implant-related infection. In our limited series we have failed to observe any benefit over uncoated nails, when used in treating cases of previously established FRI/osteomyelitis and would therefore advise caution in their use, especially in view of the high cost.

Postmortem Assessment of Olfactory Tissue Degeneration and Microvasculopathy in Patients With COVID-19.

Importance: Loss of smell is an early and common presentation of COVID-19 infection. Although it has been speculated that viral infection of olfactory neurons may be the culprit, it is unclear whether viral infection causes injuries in the olfactory bulb region. Objective: To characterize the olfactory pathology associated with COVID-19 infection in a postmortem study. Design, Setting, and Participants: This multicenter postmortem cohort study was conducted from April 7, 2020, to September 11, 2021. Deceased patients with COVID-19 and control individuals were included in the cohort. One infant with congenital anomalies was excluded. Olfactory bulb and tract tissue was collected from deceased patients with COVID-19 and appropriate controls. Histopathology, electron microscopy, droplet digital polymerase chain reaction, and immunofluorescence/immunohistochemistry studies were performed. Data analysis was conducted from February 7 to October 19, 2021. Main Outcomes and Measures: (1) Severity of degeneration, (2) losses of olfactory axons, and (3) severity of microvasculopathy in olfactory tissue. Results: Olfactory tissue from 23 deceased patients with COVID-19 (median [IQR] age, 62 [49-69] years; 14 men [60.9%]) and 14 control individuals (median [IQR] age, 53.5 [33.25-65] years; 7 men [50%]) was included in the analysis. The mean (SD) axon pathology score (range, 1-3) was 1.921 (0.569) in patients with COVID-19 and 1.198 (0.208) in controls (P < .001), whereas axon density was 2.973 (0.963) × 104/mm2 in patients with COVID-19 and 3.867 (0.670) × 104/mm2 in controls (P = .002). Concomitant endothelial injury of the microvasculature was also noted in olfactory tissue. The mean (SD) microvasculopathy score (range, 1-3) was 1.907 (0.490) in patients with COVID-19 and 1.405 (0.233) in control individuals (P < .001). Both the axon and microvascular pathology was worse in patients with COVID-19 with smell alterations than those with intact smell (mean [SD] axon pathology score, 2.260 [0.457] vs 1.63 [0.426]; P = .002; mean [SD] microvasculopathy score, 2.154 [0.528] vs 1.694 [0.329]; P = .02) but was not associated with clinical severity, timing of infection, or presence of virus. Conclusions and Relevance: This study found that COVID-19 infection is associated with axon injuries and microvasculopathy in olfactory tissue. The striking axonal pathology in some cases indicates that olfactory dysfunction in COVID-19 infection may be severe and permanent.

Effect of composite coating on insertion mechanics of needle structure in soft materials.

This research aims to study the effect of a composite coating comprised of polydopamine (PDA), polytetrafluoroethylene (PTFE), and activated Carbon on the insertion mechanics of surgical needles in tissues i.e., polyvinyl chloride (PVC) tissue phantom and bovine kidney. A needle insertion and extraction test system was designed and constructed to measure the insertion and extraction forces. It was found that the composite coating on the needle surface decreases the maximum average insertion and extraction forces by 62% and 64%, respectively, when tested in PVC tissue phantom and by 49% and 30%, respectively, in bovine kidney tissue. Additionally, an Atomic Force Microscope study was performed to characterize the surface properties of the coated needles. It was found that the composite coating reduced the friction force on the needle surface by 65.7%. The decrease in these forces is critical in minimizing tissue damage and decreasing needle path deviation or deflection during percutaneous procedures.

Strategies and outcomes in severe open tibial shaft fractures at a major trauma center: A large retrospective case-series.

BACKGROUND: Severe open tibia fractures are challenging to treat with a lack of published clear management strategies. Our aim was to provide an overview of the largest single-center experience in the literature, with minimum 1-year follow-up, of adult type 3 open tibial shaft fractures at Cambridge University Hospitals (a United Kingdom major trauma center). We sought to define patient characteristics and our main outcome measures were infection, union and re-fracture. AIM: To retrospectively define patient and injury characteristics, present our surgical methods and analyze our outcomes-namely infection, union and re-fracture rates. METHODS: Consecutive series of 74 patients with 75 open tibial fractures treated between 2014 and 2020 (26 classified as Gustilo-Anderson 3A, 47 were 3B and two were 3C). Nine patients underwent intramedullary nailing (IMN), 61 underwent Taylor spatial frame (TSF) fixation and 5 were treated with Masquelet technique (IMN and subsequent bone grafting). RESULTS: Mean follow-up was 16 mo (IMN) and 25 mo (TSF). We had an infection rate of 6.7% (5), non-union rate of 4% (3) and re-fracture rate of 2.7% (2). Average time to union was 22 wk for IMN and 38.6 wk for TSF. Thirty-three cases had a bone defect with a mean of 5.4 cm (2-11). Patient age, sex, diabetes, smoking status or injury severity did not have a significant effect on union time with either fixation method. Our limb salvage rate was 98.7%. CONCLUSION: Grade 1 to 3A injuries can effectively be treated with reamed or unreamed IMN. Grade 3B/C injuries are best treated by circular external fixators as they provide good, reproducible outcomes and allow large bone defects to be addressed via distraction osteogenesis.

Traumatic Brain Injury Severity, Neuropathophysiology, and Clinical Outcome: Insights from Multimodal Neuroimaging.

BACKGROUND: The relationship between the acute clinical presentation of patients with traumatic brain injury (TBI), long-term changes in brain structure prompted by injury and chronic functional outcome is insufficiently understood. In this preliminary study, we investigate how acute Glasgow coma score (GCS) and epileptic seizure occurrence after TBIs are statistically related to functional outcome (as quantified using the Glasgow Outcome Score) and to the extent of cortical thinning observed 6 months after the traumatic event. METHODS: Using multivariate linear regression, the extent to which the acute GCS and epileptic seizure occurrence (predictor variables) correlate with structural brain changes (relative cortical atrophy) was examined in a group of 33 TBI patients. The statistical significance of the correlation between relative cortical atrophy and the Glasgow Outcome Score was also investigated. RESULTS: A statistically significant correlative relationship between cortical thinning and the predictor variables (acute GCS and seizure occurrence) was identified in the study sample. Regions where the statistical model was found to have highest statistical reliability in predicting both gray matter atrophy and neurological outcome include the frontopolar, middle frontal, postcentral, paracentral, middle temporal, angular, and lingual gyri. In addition, relative atrophy and GOS were also found to be significantly correlated over large portions of the cortex. CONCLUSION: This study contributes to our understanding of the relationship between clinical descriptors of acute TBI, the extent of injury-related chronic brain changes and neurological outcome. This is partly because the brain areas where cortical thinning was found to be correlated with GCS and with seizure occurrence are implicated in executive control, sensory function, motor acuity, memory, and language, all of which may be affected by TBI. Thus, our quantification suggests the existence of a statistical relationship between acute clinical presentation, on the one hand, and structural/functional brain features which are particularly susceptible to post-injury degradation, on the other hand.

Chondrogenic potential of bone marrow-derived mesenchymal stem cells on a novel, auricular-shaped, nanocomposite scaffold.

Reconstruction of the human auricle remains a challenge to plastic surgeons, and current approaches are not ideal. Tissue engineering provides a promising alternative. This study aims to evaluate the chondrogenic potential of bone marrow-derived mesenchymal stem cells on a novel, auricular-shaped polymer. The proposed polyhedral oligomeric silsesquioxane-modified poly(hexanolactone/carbonate)urethane/urea nanocomposite polymer has already been transplanted in patients as the world's first synthetic trachea, tear duct and vascular bypass graft. The nanocomposite scaffold was fabricated via a coagulation/salt-leaching method and shaped into an auricle. Adult bone marrow-derived mesenchymal stem cells were isolated, cultured and seeded onto the scaffold. On day 21, samples were sent for scanning electron microscopy, histology and immunofluorescence to assess for neocartilage formation. Cell viability assay confirmed cytocompatability and normal patterns of cellular growth at 7, 14 and 21 days after culture. This study demonstrates the potential of a novel polyhedral oligomeric silsesquioxane-modified poly(hexanolactone/carbonate)urethane/urea scaffold for culturing bone marrow-derived mesenchymal stem cells in chondrogenic medium to produce an auricular-shaped construct. This is supported by scanning electron microscopy, histological and immunofluorescence analysis revealing markers of chondrogenesis including collagen type II, SOX-9, glycosaminoglycan and elastin. To the best of our knowledge, this is the first report of stem cell application on an auricular-shaped scaffold for tissue engineering purposes. Although many obstacles remain in producing a functional auricle, this is a promising step forward.

The spectrum of pyruvate dehydrogenase complex deficiency: clinical, biochemical and genetic features in 371 patients.

CONTEXT: Pyruvate dehydrogenase complex (PDC) deficiency is a genetic mitochondrial disorder commonly associated with lactic acidosis, progressive neurological and neuromuscular degeneration and, usually, death during childhood. There has been no recent comprehensive analysis of the natural history and clinical course of this disease. OBJECTIVE: We reviewed 371 cases of PDC deficiency, published between 1970 and 2010, that involved defects in subunits E1α and E1ß and components E1, E2, E3 and the E3 binding protein of the complex. DATA SOURCES AND EXTRACTION: English language peer-reviewed publications were identified, primarily by using PubMed and Google Scholar search engines. RESULTS: Neurodevelopmental delay and hypotonia were the commonest clinical signs of PDC deficiency. Structural brain abnormalities frequently included ventriculomegaly, dysgenesis of the corpus callosum and neuroimaging findings typical of Leigh syndrome. Neither gender nor any clinical or neuroimaging feature differentiated the various biochemical etiologies of the disease. Patients who died were younger, presented clinically earlier and had higher blood lactate levels and lower residual enzyme activities than subjects who were still alive at the time of reporting. Survival bore no relationship to the underlying biochemical or genetic abnormality or to gender. CONCLUSIONS: Although the clinical spectrum of PDC deficiency is broad, the dominant clinical phenotype includes presentation during the first year of life; neurological and neuromuscular degeneration; structural lesions revealed by neuroimaging; lactic acidosis and a blood lactate:pyruvate ratio ≤ 20.

Tissue engineering: revolution and challenge in auricular cartilage reconstruction.

External ear reconstruction for congenital deformity such as microtia or following trauma remains one of the greatest challenges for reconstructive plastic surgeons. The problems faced in reconstructing the intricate ear framework are highly complex. A durable, inert material that is resistant to scar contracture is required. To date, no material, autologous or prosthetic, is available that perfectly mimics the shapely elastic cartilage found in the ear. Current procedure involves autologous costal cartilage that is sculpted to create a framework for the overlying soft tissues. However, this is associated with donor-site morbidity, and few surgeons worldwide are skilled in the techniques required to obtain excellent results. Various alloplastic materials have therefore been used as a framework. However, a degree of immunogenicity and infection and extrusion are inevitable, and results are often disappointing. Tissue-engineered cartilage is an alternative approach but, despite significant progress in this area, many problems remain. These need to be addressed before routine clinical application will become possible. The current tissue-engineered options are fragile and inflexible. The next generation of auricular cartilage engineering is promising, with smart materials to enhance cell growth and integration, and the application of stem cells in a clinical setting. More recently, the authors' team designed the world's first entirely synthetic trachea composed of a novel nanocomposite material seeded with the patient's own stem cells. This was successfully transplanted in a patient at the Karolinska Hospital in Sweden and may translate into a tissue-engineered auricle in the future.

The spectrum of pyruvate dehydrogenase complex deficiency: clinical, biochemical and genetic features in 371 patients.

CONTEXT: Pyruvate dehydrogenase complex (PDC) deficiency is a genetic mitochondrial disorder commonly associated with lactic acidosis, progressive neurological and neuromuscular degeneration and, usually, death during childhood. There has been no recent comprehensive analysis of the natural history and clinical course of this disease. OBJECTIVE: We reviewed 371 cases of PDC deficiency, published between 1970 and 2010, that involved defects in subunits E1α and E1ß and components E1, E2, E3 and the E3 binding protein of the complex. DATA SOURCES AND EXTRACTION: English language peer-reviewed publications were identified, primarily by using PubMed and Google Scholar search engines. RESULTS: Neurodevelopmental delay and hypotonia were the commonest clinical signs of PDC deficiency. Structural brain abnormalities frequently included ventriculomegaly, dysgenesis of the corpus callosum and neuroimaging findings typical of Leigh syndrome. Neither gender nor any clinical or neuroimaging feature differentiated the various biochemical etiologies of the disease. Patients who died were younger, presented clinically earlier and had higher blood lactate levels and lower residual enzyme activities than subjects who were still alive at the time of reporting. Survival bore no relationship to the underlying biochemical or genetic abnormality or to gender. CONCLUSIONS: Although the clinical spectrum of PDC deficiency is broad, the dominant clinical phenotype includes presentation during the first year of life; neurological and neuromuscular degeneration; structural lesions revealed by neuroimaging; lactic acidosis and a blood lactate:pyruvate ratio ≤20.