Vepoloxamer improves functional recovery in rat after traumatic brain injury: A dose-response and therapeutic window study.

Traumatic brain injury (TBI) is a major cause of death and disability worldwide. There are no effective therapies available for TBI patients. Vepoloxamer is an amphiphilic polyethylene-polypropylene-polyethylene tri-block copolymer that seals membranes and restores plasma membrane integrity in damaged cells. We previously demonstrated that treatment of TBI rats with Vepoloxamer improves functional recovery. However, additional studies are needed to potentially translate Vepoloxamer treatment from preclinical studies into clinical applications. We thus conducted a study to investigate dose-response and therapeutic window of Vepoloxamer on functional recovery of adult rats after TBI. To identify the most effective dose of Vepoloxamer, male Wistar adult rats with controlled cortical impact (CCI) injury were randomly treated with 0 (vehicle), 100, 300, or 600 mg/kg of Vepoloxamer, administered intravenously (IV) at 2 h after TBI. We then performed a therapeutic window study in which the rats were treated IV with the most effective single dose of Vepoloxamer at different time points of 2 h, 4 h, 1 day, or 3 days after TBI. A battery of cognitive and neurological tests was performed. Animals were killed 35 days after TBI for histopathological analysis. Dose-response experiments showed that Vepoloxamer at all three tested doses (100, 300, 600 mg/kg) administered 2 h post injury significantly improved cognitive functional recovery, whereas Vepoloxamer at doses of 300 and 600 mg/kg, but not the 100 mg/kg dose, significantly reduced lesion volume compared to saline treatment. However, Vepoloxamer at 300 mg/kg showed significantly improved neurological and cognitive outcomes than treatment with a dose of 600 mg/kg. In addition, our data demonstrated that the dose of 300 mg/kg of Vepoloxamer administered at 2 h, 4 h, 1 day, or 3 days post injury significantly improved neurological function compared with vehicle, whereas Vepoloxamer administered at 2 h or 4 h post injury significantly improved cognitive function compared with the 1-day and 3-day treatments, with the most robust effect administered at 2 h post injury. The present study demonstrated that Vepoloxamer improves functional recovery in a dose-and time-dependent manner, with therapeutic efficacy compared with vehicle evident even when the treatment is initiated 3 days post TBI in the rat.

A Novel Method to Determine the Longitudinal Antibacterial Activity of Drug-Eluting Materials.

Ultrahigh molecular weight polyethylene (UHMWPE) is widely used in total joint arthroplasties as a load-bearing surface. Periprosthetic joint infections, the majority of which occur shortly after joint replacement, constitute almost 25% of total knee revision surgeries, and the complete eradication of bacterial infection poses a major challenge. A promising way to tackle this problem is to ensure the local sustained delivery of antibiotic concentrations sufficient to inhibit the bacteria to support routine systemic antibiotic prophylaxis. There is increased research into the development of efficient local drug delivery devices. Although established antibacterial testing methods for drugs can be used to test the antibacterial efficacy of drug-eluting materials, they are lacking in terms of providing real-time and longitudinal antibacterial efficacy data that can be correlated to the elution profiles of antibiotics from these devices. Here, we report a direct and versatile methodology to determine the antibacterial efficacy of antibiotic-eluting UHMWPE implants. This methodology can be used as a platform to avoid bacterial culture at each time point of a lengthy experiment and can also be adapted to other local drug delivery devices.

Impact of Psychologic Burden on Surgical Outcome in Empty Nose Syndrome.

OBJECTIVES /HYPOTHESIS: Empty nose syndrome (ENS) is a complicated condition currently thought to be caused by excessive surgical resection of turbinate tissue. Patients with ENS experienced significant psychological symptoms, such as depression and anxiety. This study aimed to evaluate the impact of the psychological burden on the surgical outcome of ENS. STUDY DESIGN: Prospective case series in a tertiary medical center. METHODS: Patients with ENS were prospectively recruited between 2015 and 2018. Validated instruments including the Sinonasal Outcome Test-25 (SNOT-25), Beck Depression Inventory-II (BDI-II), and Beck Anxiety Inventory (BAI) were used to evaluate patients with ENS prior to and 3, 6, and 12 months after nasal reconstruction surgery with submucosal Medpor implantation. RESULTS: A total of 54 ENS patients were enrolled during the study period. All three evaluations revealed significant improvement, and symptoms stabilized 3 months after surgery. Six months post-operatively, SNOT-25 scores were significantly associated with the pre-operative BDI-II and BAI scores (ß = 0.64 and 0.87; P = .006 and <.001, respectively). Multivariate regression model revealed that only BAI scores were significantly associated with the six-month post-operative SNOT-25 scores (adjusted ß = 0.49, P = .036). Moreover, Spearman's correlation found close relationships between the post-operative SNOT-25 and the post-operative BDI-II and BAI scores (rs = 0.751 and 0.884, both P < .001). CONCLUSIONS: Psychological evaluation can help predict surgical outcomes and identify patients with residual disease. These findings emphasize the importance of screening for psychological symptoms and structuring care by including psychological therapy in addition to surgery. LEVEL OF EVIDENCE: 4. Laryngoscope, 131:E694-E701, 2021.

Lessons Learned From Two Survivors of Greater Than 90% TBSA Full-Thickness Burn Injuries Using NovoSorb Biodegradable Temporizing Matrix™ and Autologous Skin Cell Suspension, RECELL™: A Case Series.

Since autologous split-thickness skin grafts are scarce and lab skin growth requires a significant amount of time, there are limited available treatment approaches for patients with full-thickness burns greater than 90% TBSA. Additionally, to achieve the primary goal of skin coverage and resuscitation, there must exist a balance between fluid loss and metabolic derangement. Allografts and xenografts have traditionally been used early in the process to achieve these goals. Currently, novel approaches to treatment consider the additional use of synthetic dermal substitutes and autologous skin cell suspension to improve outcomes. This case series describes the treatment course of patients with greater than 90% TBSA full-thickness burn injuries using a staged, multifaceted approach of using NovoSorb Biodegradable Temporizing Matrix™ as the primary dermal substitute in conjunction with a RECELL™ Autologous Cell Suspensions Device applied with autograft and allograft to achieve improved resuscitation, limiting fluid loss, and finally skin coverage. Allograft and NovoSorb Biodegradable Temporizing Matrix™ were used early to cover excised burns, resulting in improved metabolic control by limiting the systemic inflammatory response syndrome and fluid loss. Both patients survived using this approach.

Antibacterial and anti-inflammatory ultrahigh molecular weight polyethylene/tea polyphenol blends for artificial joint applications.

Periprosthetic joint infection (PJI) is one of the main causes for the failure of joint arthroplasty. In view of the limited clinical effect of oral/injectable antibiotics and the drug resistance problem, there is a pressing need to develop antibacterial implants with therapeutic antimicrobial properties. In this work, we prepared a highly antibacterial ultrahigh molecular weight polyethylene (UHMWPE) implant by incorporating tea polyphenols. The presence of tea polyphenols not only improved the oxidation stability of irradiated UHMWPE, but also gave it the desirable antibacterial property. The potent antibacterial activity was attributed to the tea polyphenols that produced excess intracellular reactive oxygen species and destroyed the bacterial membrane structure. The tea polyphenol-blended UHMWPE had no biological toxicity to human adipose-derived stem cells and effectively reduced bacteria-induced inflammation in vivo. These results indicate that tea polyphenol-blended UHMWPE is promising for joint replacement prostheses with multifunctionality to meet patient satisfaction.

Randomized clinical trial of negative pressure wound therapy as an adjunctive treatment for small-area thermal burns in children.

BACKGROUND: The efficacy of negative pressure wound therapy (NPWT) in the acute management of burns remains unclear. The purpose of this trial was to compare standard Acticoat™ and Mepitel™ dressings with combined Acticoat™, Mepitel™ and continuous NPWT to determine the effect of adjunctive NPWT on re-epithelialization in paediatric burns. METHODS: This two-arm, single-centre RCT recruited children with acute thermal burns covering less than 5 per cent of their total body surface area. The primary outcome was time to re-epithelialization. Blinded assessments were performed using photographs captured every 3-5 days until discharge. Secondary measures included pain, itch, grafting, perfusion and scar management referrals. RESULTS: Some 114 patients were randomized. Median time to re-epithelialization was 8 (i.q.r. 7-11) days in the NPWT group and 10 (8-14) days in the control group. In a multivariable model, NPWT decreased the expected time to wound closure by 22 (95 per cent c.i. 7 to 34) per cent (P = 0·005). The risk of referral to scar management was reduced by 60 (18 to 81) per cent (P = 0·013). Four participants in the control group and one in the NPWT group underwent grafting. There were no statistically significant differences between groups in pain, itch or laser Doppler measures of perfusion. Adverse events were rare and minor, although NPWT carried a moderate treatment burden, with ten patients discontinuing early. CONCLUSION: Adjunctive NPWT hastened re-epithelialization in small-area burn injuries in children, but had a greater treatment burden than standard dressings alone. Registration number: ACTRN12618000256279 ( http://ANZCTR.org.au).

ANTECEDENTES: La eficacia del tratamiento de las heridas con presión negativa (negative pressure wound therapy, NPWT) en el tratamiento agudo de las quemaduras sigue sin estar claro. El propósito de este ensayo clínico fue comparar los apósitos estándar del tipo Acticoat™ y Mepitel™ con la combinación de Acticoat™, Mepitel™ y NPWT continua para determinar el efecto de la adición de NPWT en la reepitelización de las quemaduras en pediatría. MÉTODOS: Ensayo controlado y aleatorizado, con dos brazos y unicéntrico, que reclutó niños con quemaduras térmicas agudas que afectaban < 5% de la superficie corporal total. El resultado primario fue el tiempo hasta la reepitelización. Se realizaron evaluaciones a ciegas utilizando fotografías tomadas cada 3-5 días hasta el alta hospitalaria. Las medidas secundarias incluían dolor, picor, injerto, perfusión y derivación para el tratamiento de las cicatrices. RESULTADOS: Se aleatorizaron un total de 114 pacientes. La mediana de tiempo hasta la reepitelización fue 8 días (rango intercuartílico, interquartile range, IQR 7-11) en el grupo NPWT y 10 días (8-14) en el grupo control. En el modelo multivariable, el uso de NPWT disminuyó los días previstos hasta el cierre de la herida en un 22% (i.c. del 95% 7-34%; P = 0,005). El riesgo de ser derivado para el tratamiento de la cicatriz se redujo en un 60% (18-81%; P = 0,013). Cuatro participantes en el grupo control y uno en el grupo NPWT fueron sometidos a injertos. No hubo diferencias estadísticamente significativas en el dolor, picor, o mediciones de la perfusión con Doppler laser. Los eventos adversos fueron raros y menores, aunque NPWT conllevó una carga de tratamiento moderada con 10 pacientes que lo suspendieron precozmente. CONCLUSIÓN: El tratamiento complementario de la herida con presión negativa acelera el tiempo hasta la reepitelización en quemaduras de pequeña extensión en niños, pero implica una mayor carga de tratamiento.

2-year results of an RCT of 2 uncemented isoelastic monoblock acetabular components: lower wear rate with vitamin E blended highly cross-linked polyethylene compared to ultra-high molecular weight polyethylene.

Background and purpose - The long-term survival of arthroplasty components may be limited by polyethylene wear-related problems such as periprosthetic osteolysis and aseptic loosening. Highly cross-linked polyethylene (HXLPE) blended with vitamin E was introduced to improve oxidative stability and to avoid long-term embrittlement. This study clinically compares the tribological behavior and clinical outcome of vitamin E blended HXLPE with ultra-high molecular weight polyethylene (UHMWPE) in an isoelastic monoblock cup for uncemented total hip arthroplasty.Patients and methods - In this randomized controlled trial (RCT), 199 patients were included: 102 patients received the vitamin E blended HXLPE cup, 97 patients the UHMWPE cup. Clinical and radiographic parameters were obtained preoperatively, directly postoperative and at 3, 12, and 24 months. Wear rates were compared using the mean linear femoral head penetration (FHP) rate.Results - 188 patients (94%) completed the 2-year follow-up. Mean patient satisfaction was higher in the vitamin E blended HXLPE group (8.9 [1]) than in in the control group (8.5 [2], p = 0.03). The Harris Hip Score (HHS) was higher in the vitamin E blended HXLPE group (95 [8]) than in the control group (92 [11], p = 0.3). The FHP rate was lower in the vitamin E blended HXLPE group: 0.046 mm/year compared with 0.056 mm/year in the control group (p = 0.05). No adverse reactions associated with the clinical application of vitamin E blended HXLPE were observed during follow-up, with an excellent 2-year survival to revision rate of 98% for both cups.Interpretation - This study shows the superior performance of the HXLPE blended with vitamin E acetabular cup with lower linear femoral head penetration rates and better clinical results compared with the UHMWPE acetabular cup after 2 years.

A randomised bite force study assessing two currently marketed denture adhesive products compared with no-adhesive control.

Unlike other oral care products, there are limited technologies in the denture adhesive category with the majority based on polymethyl vinyl ether/maleic anhydride (PVM/MA) polymer. Carbomer-based denture adhesives are less well studied, and there are few clinical studies directly comparing performance of denture adhesives based on different technologies. This single-centre, randomised, three-treatment, three-period, examiner-blind, crossover study compared a carbomer-based denture adhesive (Test adhesive) with a PVM/MA-based adhesive (Reference adhesive) and no adhesive using incisal bite force measurements (area over baseline over 12 hr; AOB0-12) in participants with a well-made and at least moderately well-fitting complete maxillary denture. Eligible participants were randomised to a treatment sequence and bit on a force transducer with increasing force until their maxillary denture dislodged. This procedure was performed prior to treatment application (baseline) and at 0.5, 1, 3, 6, 9, and 12 hr following application. Forty-four participants were included in the modified intent-to-treat population. AOB0-12 favoured both Test adhesive to No adhesive (difference: 2.12 lbs; 95% CI [1.25, 3.00]; p < 0.0001) and Reference adhesive to No adhesive (difference: 2.76 lbs; 95% CI [1.89, 3.63]; p < 0.0001). There was a numerical difference in AOB0-12 for Test versus Reference adhesive (-0.63 lbs; [-1.51, 0.25]); however, this was not statistically significant (p = 0.1555). Treatments were generally well tolerated. Both PVM/MA and carbomer-based denture adhesives demonstrated statistically significantly superior denture retention compared with no adhesive over 12 hr, with no statistically significant difference between adhesives.

Can Fiber Application Affect the Fracture Strength of Endodontically Treated Teeth Restored with a Low Viscosity Bulk-Fill Composite?

OBJECTIVE: The aim of this study is to evaluate the effects of different fiber insertion techniques and thermomechanical aging on the fracture resistance of endodontically treated mandibular premolar teeth restored using bulk-fill composites. MATERIALS AND METHODS: Eighty human mandibular premolar teeth were randomly divided into eight groups: Group IN, Group BF, Group PRF1, Group PRF2, Group IN-TMA, Group BF-TMA, Group PRF1-TMA ,and Group PRF2-TMA. Group IN (intact) and Group IN-TMA (intact but subjected to thermomechanical aging) served as control groups. In the other six groups, endodontic treatment was performed and standardized mesio-occluso-distal (MOD) cavities were prepared. In BF, PRF1, and PRF2, the cavities were restored with bulk-fill composite only, bulk-fill/Ribbond, and bulk-fill/additional Ribbond, respectively. In BF-TMA, PRF1-TMA, and PRF2-TMA, the teeth were subjected to thermomechanical aging after the restorations. All of the teeth were fractured on the universal testing machine. Fracture surfaces were analyzed with a stereomicroscope. RESULTS: Control groups showed significantly higher fracture strengths than tested groups (P<0.05). No statistically significant difference was observed among the tested groups (P>0.05). Most of the favorable fractures were seen in PRF1, PRF2, and PRF2-TMA. Most of the unfavorable fractures were seen in BF-TMA. CONCLUSIONS: Although fiber insertion with different techniques did not increase the fracture strength of teeth restored with bulk-fill composites, it increased the favorable fracture modes. Thermomechanical aging did not change the fracture strength of the groups.

A rugged, self-sterilizing antimicrobial copper coating on ultra-high molecular weight polyethylene: a preliminary study on the feasibility of an antimicrobial prosthetic joint material.

We report here for the first time how the combination of a precursor solution and low temperature (170 °C) aerosol assisted chemical vapour deposition were used to bond a copper coating to ultra-high molecular weight polyethylene (UHMWPE) and promote robustness. This metallic thin film remained intact on the UHMWPE substrate after the Scotch tape test and showed notable wear-resistance after 10 cycles of sand paper-abrasion. Antimicrobial assays against both Escherichia coli and Staphylococcus aureus revealed potent dark bactericidal activity with 99.999% reduction in bacterial number within 15 minutes. These results suggest that the modified UHMWPE could be a potential candidate for antimicrobial plastics and in the long term may find application in prosthetic joint applications.

Facial Implants: Controversies and Criticism. A Comprehensive Review of the Current Literature.

BACKGROUND: Polyethylene (Medpor) and silicone are two of the most popular materials used today for facial skeleton implantation. Previous studies have identified common complications with the use of these implants, but patient follow-up has been short. This review of the literature examines complications and patient follow-up in cases using Medpor and silicone implants for reconstructive and aesthetic operations of the mid and lower face over the past 20 years. METHODS: A literature search was conducted through the PubMed database. Keywords used were as follows: ("mandible implants" or "malar implants" or "chin implants") AND ("reconstruction" or "augmentation") AND ("Medpor" or "silicone"). RESULTS: There were nine studies with 626 patients in the Medpor group and five studies with 365 patients in the silicone group. The silicone group had a higher incidence of infections and displacements. The Medpor group showed a higher incidence of prominence problems. Exposure/extrusion rates were low for both implant types. Chin and mandibular implants were the safest, whereas malar implants had a high incidence of prominence problems. The average follow-up for Medpor was 36.6 months and 24 months for silicone. There were wide ranges of follow-up times, from 2 weeks up to 15 years. A limited number of articles included an averaged time within their ranges. Reported follow-up times were not linked to specific complications. CONCLUSIONS: Medpor implantation is more common than silicone. Complication rates are low with the use of both materials. Patient follow-up is deficient and has not improved in the past 20 years, raising questions on the reliability of complication rates.

Investigation of mechanical compatibility of hernia meshes and human abdominal fascia.

OBJECTIVE: Understanding the biomechanical properties of hernia meshes is essential in facilitating their selection. The aim of this study was to evaluate the mechanical compatibility of hernia meshes and human abdominal fascia and assess their applicability in hernia repair. METHODS: Uniaxial tensile tests were performed. A total of eight hernia meshes were tested - three standard meshes (Surgimesh®, Surgipro™, TecnoMesh®) and five light-weight meshes (Optilene®, TiO2Mesh™, Parietex™, Vypro™ II, Ultrapro™). RESULTS: The secant modulus at 5% strain and the level of orthotropy (the ratio between tensile stress in the longitudinal and the transversal direction) at 5% strain were calculated from the stress-stretch ratio curves. The impact of pore size and thickness on the elastic properties of these meshes was determined. The relationships between density and elasticity as well as between elasticity and the strain developed at 16 N/cm load were presented. The resulting mechanical properties of meshes were compared to the elasticity, orthotropy and deformability of human abdominal fascia. CONCLUSIONS: Vypro™ II and Parietex™ brands display properties similar to those of fascia in both directions. The TiO2Mesh™ and Ultrapro™ display deformability close to the deformability at 16 N/cm of the fascia transversalis. Only the Vypro™ II brand's orthotropy is similar to that of fascia.

Biophysical characterization of layer-by-layer synthesis of aptamer-drug microparticles for enhanced cell targeting.

Targeted delivery of drug molecules to specific cells in mammalian systems demonstrates a great potential to enhance the efficacy of current pharmaceutical therapies. Conventional strategies for pharmaceutical delivery are often associated with poor therapeutic indices and high systemic cytotoxicity, and this result in poor disease suppression, low surviving rates, and potential contraindication of drug formulation. The emergence of aptamers has elicited new research interests into enhanced targeted drug delivery due to their unique characteristics as targeting elements. Aptamers can be engineered to bind to their cognate cellular targets with high affinity and specificity, and this is important to navigate active drug molecules and deliver sufficient dosage to targeted malignant cells. However, the targeting performance of aptamers can be impacted by several factors including endonuclease-mediated degradation, rapid renal filtration, biochemical complexation, and cell membrane electrostatic repulsion. This has subsequently led to the development of smart aptamer-immobilized biopolymer systems as delivery vehicles for controlled and sustained drug release to specific cells at effective therapeutic dosage and minimal systemic cytotoxicity. This article reports the synthesis and in vitro characterization of a novel multi-layer co-polymeric targeted drug delivery system based on drug-loaded PLGA-Aptamer-PEI (DPAP) formulation with a stage-wise delivery mechanism. A thrombin-specific DNA aptamer was used to develop the DPAP system while Bovine Serum Albumin (BSA) was used as a biopharmaceutical drug in the synthesis process by ultrasonication. Biophysical characterization of the DPAP system showed a spherical shaped particulate formulation with a unimodal particle size distribution of average size ∼0.685 µm and a zeta potential of +0.82 mV. The DPAP formulation showed a high encapsulation efficiency of 89.4 ± 3.6%, a loading capacity of 17.89 ± 0.72 mg BSA protein/100 mg PLGA polymeric particles, low cytotoxicity and a controlled drug release characteristics in 43 days. The results demonstrate a great promise in the development of DPAP formulation for enhanced in vivo cell targeting. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:249-261, 2018.

A Shift in the Orbit: Immediate Endoscopic Reconstruction After Transnasal Orbital Tumors Resection.

Endoscopic endonasal resection of orbital lesions is a safe and common approach. Nevertheless, medial orbital wall defects following the procedure are not routinely addressed, potentially leading to diplopia and enophthalmos. In this article, the authors propose a new technique for purely endoscopic endonasal reconstruction of orbital wall defects following endoscopic endonasal resection of orbital lesions.The patient, a 43-year-old male, suffering from right exophthalmos and diplopia due to a venous malformation of the right orbit underwent endoscopic endonasal resection of the mass. Excision was followed by immediate transnasal endoscopic reconstruction with a commercially available porous polyethylene mesh (Medpor).The postoperative course was uneventful. The patient did not report any residual orbital asymmetry or diplopia. No recurrence of the venous malformation, mesh infection, or reconstruction instability was reported during the follow-up.The authors believe that this new technique could spur head and neck surgeons in strategically rethinking their approach to orbital tumors, proposing reconstruction to patients on a routine basis, and developing even more reliable and manageable solutions.

Raman spectroscopy of biomedical polyethylenes.

With the development of three-dimensional Raman algorithms for local mapping of oxidation and plastic strain, and the ability to resolve molecular orientation patterns with microscopic spatial resolution, there is an opportunity to re-examine many of the foundations on which our understanding of biomedical grade ultra-high molecular weight polyethylenes (UHMWPEs) are based. By implementing polarized Raman spectroscopy into an automatized tool with an improved precision in non-destructively resolving Euler angles, oxidation levels, and microscopic strain, we become capable to make accurate and traceable measurements of the in vitro and in vivo tribological responses of a variety of commercially available UHMWPE bearings for artificial hip and knee joints. In this paper, we first review the foundations and the main algorithms for Raman analyses of oxidation and strain of biomedical polyethylene. Then, we critically re-examine a large body of Raman data previously collected on different polyethylene joint components after in vitro testing or in vivo service, in order to shed new light on an area of particular importance to joint orthopedics: the microscopic nature of UHMWPE surface degradation in the human body. A complex scenario of physical chemistry appears from the Raman analyses, which highlights the importance of molecular-scale phenomena besides mere microstructural changes. The availability of the Raman microscopic probe for visualizing oxidation patterns unveiled striking findings related to the chemical contribution to wear degradation: chain-breaking and subsequent formation of carboxylic acid sites preferentially occur in correspondence of third-phase regions, and they are triggered by emission of dehydroxylated oxygen from ceramic oxide counterparts. These findings profoundly differ from more popular (and simplistic) notions of mechanistic tribology adopted in analyzing joint simulator data. Statement of Significance This review was dedicated to the theoretical and experimental evaluation of the commercially available biomedical polyethylene samples by Raman spectroscopy with regard to their molecular textures, oxidative patterns, and plastic strain at the microscopic level in the three dimensions of the Euclidean space. The main achievements could be listed, as follow: (i) visualization of molecular patterns at the surface of UHMWPE bearings operating against metallic components; (ii) differentiation between wear and creep deformation in retrievals; (iii) non-destructive mapping of oxidative patterns; and, (iv) the clarification of chemical interactions between oxide/non-oxide ceramic heads and advanced UHMWPE liners.

Highly crosslinked polyethylene: a safe alternative to conventional polyethylene for dual mobility cup mobile component. A biomechanical validation.

PURPOSE: Dual mobility cup (DMC) consists of a cobalt-chromium (CoCr) alloy cup articulated with a polyethylene (PE) mobile component capturing the femoral head in force using a snap-fit technique. This biomechanical study was the first to evaluate and compare the generation of cracks in the retentive area of DMC mobile components made of highly crosslinked PE (XLPE) or conventional ultra-high molecular weight PE (UHMWPE). METHODS: Eighty mobile components designed for a 52-mm diameter Symbol® DMC (Dedienne Santé, Mauguio, France) and a 28-mm diameter femoral head were analyzed. Four groups of 20 mobile components were constituted according to the PE material: raw UHMWPE, sterilized UHMWPE, annealed XLPE and remelted XLPE. Ten mobile components in each group were impacted with a 28-mm diameter CoCr femoral head using a snap-fit technique. The occurrence, location and area of the cracks in the retentive area were investigated using micro-CT (Skyscan 1176®, Bruker, Aarsellar, Belgium) with a 35 µm nominal isotropic voxel size by two observers blinded to the PE material and impaction or not of the mobile components. RESULTS: Compared to conventional UHMWPE, the femoral head snap-fit did not generate more or wider cracks in the retentive area of annealed or remelted XLPE mobile components. CONCLUSION: This biomechanical study suggests that XLPE in DMC could be a safe alternative to conventional UHMWPE regarding the generation of cracks in the retentive area related to the femoral head snap-fit.

Steven Johnson Syndrome and Toxic Epidermal Necrolysis in a burn unit: A 15-year experience.

INTRODUCTION: The diffuse epidermal exfoliation seen in Steven Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) is similar to skin loss in second degree burns, and many of these patients are referred for treatment at burn centers. Treatment can differ markedly from center to center, and mortality can range from 25% to 70%, including a considerable morbidity. However, our experience over a 15-year period from 2000 to 2015 with 40 patients found a mortality rate of only 10% (4/40). The purpose of this paper is to discuss our treatment algorithm as a model for other centers treating SJS/TENs patients. METHODS: Records were reviewed for all patients admitted to the LAC+USC burn unit between 2000 and 2015 and 40 patients were identified with biopsy-proven SJS or TENS. These cases were reviewed for age, gender, initial and greatest TBSA, causative drug, pre-existing medical conditions, and morbidity and mortality. All data were entered into the SPSS statistical software package and all statistical analyses were performed using this program. RESULTS: Our treatment algorithm focused on early referral to a specialty burn unit, immediate discontinuation of the offending drug, fluid resuscitation, nutritional supplementation, and meticulous wound care. Average time to transfer to a burn unit was 3.36 days. Silver-releasing antimicrobial dressings were applied to the affected skin surface and changed every 3 days. Mupirocin coated petroleum gauze was used for facial involvement. Steroids were tapered and discontinued if initiated at an outside facility (58% of patients), and starting after 2001, all patients received a course of IVIG. All patients received fluid resuscitation and the majority received supplemental tube feedings (69%). Average length of total stay was 17.1 days and length of ICU stay 15.9 days. While 44% were transferred to another facility for further rehabilitative care, 37% of patients discharge to home. In patients discharged home with complete resolution of skin lesions, time to healing was an average of 14 days. DISCUSSION: With our 10% mortality rate in 40 patients, our study represents a relatively large study population while maintaining a relatively low mortality rate. The demographic data from our study largely aligns with the existing literature, and we therefore feel that our low mortality rate is due to our treatment algorithm, rather than to a less severe pathology in our patient population. This claim is supported by a standard mortality ratio of 1.68. This ratio proves a significantly improved mortality than would be expected based on disease severity on admission.

Application for MEDPOR Surgical Implant in Modified Penile Elongation: Review of 19 Cases.

OBJECTIVE: To investigate the application of MEDPOR surgical implant in modified penile elongation. METHODS: The suspensory ligaments were divided, and cavernous bodies of crus were partially mobilized, so as to release part of the cavernous bodies from inferior ramus of pubis. Then, the penis was elongated sufficiently. MEDPOR surgical implants (MEDPOR; high-density porous polyethylene, Howmedica Osteonics Corp. Newnan, Ga) were inserted between the cavernous bodies and pubic symphysis. Local fat flap was transposed to fill the front space of pubis to make sure of the effective elongation of penis and improve the appearance of mons pubis. RESULTS: Nineteen cases of micropenis were treated. The average length of the penis was 5.23 cm in the static state and 7.83 cm in erectile state before operation. After the operation, it increased to 8.63 cm in the static state and 11.36 cm in erectile state. CONCLUSIONS: Application for MEDPOR surgical implant in modified penile elongation can make sure of the effective elongation of penis and improve the appearance of mons pubis.

Wear products of total hip arthroplasty: The case of polyethylene.

Among the bearing surfaces involved in a total hip arthroplasty, ultra-high molecular weight polyethylene (UHMWPE) is the weak link. It is submitted to the friction of a harder bearing, producing wear particles, which, in turn, initiate an inflammatory reaction ultimately leading to osteolysis. This kind of bone deterioration sometimes turns out to an aggressive granuloma and may provoke implant loosening. Wear resistance of UHMWPE depends on its molecular weight and crystallinity. Some steps of the manufacturing process were improved to optimize its tribological properties and to slow down degradation resulting from mechanical (abrasion) and chemical (oxidation) phenomena. Its preparation and conservation must be performed in an inert atmosphere, i.e. without ambient oxygen. Its resistance to abrasion depends on its cross-linking degree. Its cross-linking rate was observed to increase proportionally to the irradiation doses, improving its wear resistance. However, its mechanical properties are impaired and moreover, it becomes oxidation sensitive. It is therefore necessary to submit it to a thermal treatment to eliminate free radicals that were produced during irradiation. More recently impregnation by vitamin E, a powerful anti-oxidant product, was proposed to preserve the polymer from in vivo oxidation while maintaining its mechanical properties. We raised the hypothesis that last-generation UHMWPE could offer the same wear resistance as the most performing bearings (ceramic-on-ceramic). Recent clinical results confirm the tribological performance of highly crosslinked UHMWPE in vivo. However, it remains to be seen whether this excellent wear resistance would persist under eccentric load such as edge loading, and if, in the long run, this kind of bearing proves capable of reducing the risk of osteolysis in young and active patients.

Comparison of Polyethylene Wear before and after Hip Revision with Liner Exchange Fixed with the Original Locking Mechanism.

OBJECTIVE: To compare the wear of conventional ultra-high molecular weight polyethylene (CUHMWPE) and highly cross-linked polyethylene (HCLPE) in hip revision with liner exchange fixed with original locking mechanism using analysis of history medical data. METHODS: From Jan. 1, 2000, to Dec. 31, 2007, 26 patients (with 29 involved hips) underwent liner exchange revision fixed with the original locking mechanism due to wear of CUHMWPE and/or osteolysis. The mean age was 53 ± 9 years at the time of the primary total hip arthroplasty (THA) and 64 ± 9 years at the revision. The exchanged liners (Marathon, Depuy) were made of HCLPE. Annual X-rays were used to measure linear wear and osteolysis. The annual linear penetration was measured using PolyWare® software (Draftware Inc.). Annual Harris Hip Scores(HSS) were recorded. RESULTS: The mean follow-up time between the primary and revision THAs was 11 ± 2 years and 8 ± 2 years after revision. The mean Harris Hip Score(HHS) before primary THA, 1 year after primary THA, before revision and 1 year after revision was 43±5, 85±5, 71±6, 83±7 individually. The mean penetration of the CUHMWPE and HCLPE liners occurring in the first year were 0.44 ± 0.28 mm and 0.38 ± 0.14 mm, respectively (p = 0.211). The mean annual linear penetration of CUHMWPE and HCLPE from the second year onward were 0.29±0.09 mm and 0.08 ± 0.03 mm respectively (p <0.01). All THAs with CUHMWPE showed osteolysis on acetabular and/or femoral side before revision. No HCLPE liner showed osteolysis at the last follow-up. Conclusion: The CUHMWPE liner had a significantly higher wear rate than did the HCLPE liner. The HCLPE liner showed a satisfactory liner penetration rate after revision with isolated liner exchange fixed with the original locking mechanism.