Comparison of Supraclavicular Regional Nerve Block Versus Infraclavicular Regional Nerve Block in Distal Radial Open Reduction and Internal Fixation: A Retrospective Case Series.

Background The management of pain in patients undergoing open reduction and internal fixation (ORIF) of distal radius fractures (DRFs) remains an area of debate for anesthesiologists due to a variety of block options and no definitive superior technique among these modalities. In this retrospective case series, we compare the efficacy of supraclavicular versus infraclavicular regional nerve blocks for surgical patients undergoing distal radial ORIF operations to determine if one approach was superior. Methodology This retrospective case series included patients undergoing ORIF of a DRF at a tertiary academic medical center between April 28, 2016, and August 23, 2021. In total, 54 patients undergoing ORIF of a DRF provided written consent for the nerve block(s) on the day of surgery. Of these 54 patients, 54 (100%) underwent primary procedures. Of the 54 primary ORIF patients, 28 (52%) received the supraclavicular block, while 26 (48%) received the infraclavicular nerve block. Results The infraclavicular and supraclavicular groups did not significantly differ regarding age, gender, American Society of Anesthesiologists, weight, or body mass index. The primary (intraoperative opioid use) and secondary (postoperative opioid use, postoperative nausea and vomiting in the post-anesthetic care unit, highest and average pain scores, and time to discharge) outcomes data were included in the study. The infraclavicular and supraclavicular groups did not significantly differ in any of the assessed outcomes except for time to discharge. Conclusions The supraclavicular block approach for distal radius ORIF offers an effective and non-inferior alternative to the infraclavicular block approach concerning effective analgesia and safety.

Establishing Age-calibrated Normative PROMIS Scores for Hand and Upper Extremity Clinic.

The purpose of our study is to investigate differences in normative PROMIS upper extremity function (PROMIS-UE), physical function (PROMIS-PF), and pain interference (PROMIS-PI) scores across age cohorts in individuals without upper extremity disability. METHODS: Individuals without upper extremity disability were prospectively enrolled. Subjects were administered PROMIS-UE, PROMIS-PF, and PROMIS-PI forms. Retrospective PROMIS data for eligible subjects were also utilized. The enrolled cohort was divided into age groups: 20-39, 40-59, and 60-79 years old. ANOVA, ceiling and floor effect analysis, and kurtosis and skewness statistics were performed to assess PROMIS scores trends with age. RESULTS: This study included 346 individuals. In the 20-39 age group, mean PROMIS scores were 56.2 ± 6.1, 59.8 ± 6.9, and 43.1 ± 6.7 for PROMIS-UE, PROMIS-PF, and PROMIS-PI, respectively. In the "40-59" age group, mean PROMIS computer adaptive test scores were 53.3 ± 7.5, 55.3 ± 7.6, and 46.6 ± 7.8 for PROMIS-UE, PROMIS-PF, and PROMIS-PI, respectively. In the 60-79 age group, mean PROMIS scores were 48.4 ± 7.6, 48.5 ± 5.6, and 48.7 ± 6.9 for PROMIS-UE, PROMIS-PF, and PROMIS-PI, respectively. Differences in mean PROMIS scores were significant across all PROMIS domains and age cohorts (P < 0.001). CONCLUSION: Younger individuals without hand or upper extremity disability show higher normative PROMIS-UE and PROMIS-PF scores and lower PROMIS-PI scores, indicating greater function and less pain than older counterparts. A universal reference PROMIS score of 50 appears suboptimal for clinical assessment and decision-making in the hand and upper extremity clinic.

Nanoengineered carbon scaffolds for hydrogen storage.

Single-walled carbon nanotube (SWCNT) fibers were engineered to become a scaffold for the storage of hydrogen. Carbon nanotube fibers were swollen in oleum (fuming sulfuric acid), and organic spacer groups were covalently linked between the nanotubes using diazonium functionalization chemistry to provide 3-dimensional (3-D) frameworks for the adsorption of hydrogen molecules. These 3-D nanoengineered fibers physisorb twice as much hydrogen per unit surface area as do typical macroporous carbon materials. These fiber-based systems can have high density, and combined with the outstanding thermal conductivity of carbon nanotubes, this points a way toward solving the volumetric and heat-transfer constraints that limit some other hydrogen-storage supports.

In vitro cytotoxicity of single-walled carbon nanotube/biodegradable polymer nanocomposites.

Injectable nanocomposites made of biodegradable poly(propylene fumarate) and the crosslinking agent propylene fumarate-diacrylate as well as each of three forms of single-walled carbon nanotubes (SWNTs) were evaluated for their in vitro cytotoxicity. Unreacted components, crosslinked networks, and degradation products of the nanocomposites were investigated for their effects on cell viability using a fibroblast cell line in vitro. The results did not reveal any in vitro cytotoxicity for purified SWNTs, SWNTs functionalized with 4-tert-butylphenylene, and ultra-short SWNTs at 1- 100 microg/mL concentrations. Moreover, nearly 100% cell viability was observed on all crosslinked nanocomposites and cell attachment on their surfaces was comparable with that on tissue culture polystyrene. The degradation products of the nanocomposites displayed a dose-dependent adverse effect on cells, which was partially due to increased osmolarity by the conditions of accelerated degradation and could be overcome at diluted concentrations. These results demonstrate that all three tested nanocomposites have favorable cytocompatibility for potential use as scaffolds for bone tissue engineering applications.

"Hairy" single-walled carbon nanotubes prepared by atom transfer radical polymerization.

"Hairy nano-objects" are hybrid nanostructures comprising a core surrounded by a "hairlike" corona of flexible polymer chains, the role of which is typically to improve the solubility of the core material or to improve its dispersability and adhesion in other polymer matrices. Both aspects could be particularly useful with carbon nanotubes, especially in their applications as reinforcing agents. The controlled synthesis of hairy carbon nanotubes is accomplished by chemical modification with 2-bromopropionate followed by extension with poly(n-butyl acrylate) through atom transfer radical polymerization. The obtained hairy nanotubes are visualized at nearly molecular resolution with tapping-mode atomic force microscopy, providing insight into the uniformity of grafted chain lengths and grafting density. The grafting densities vary from approximately 1.0-10.0 chains nm(-1) along the nanotubes. Such a wide range of grafting density may indicate some chemical heterogeneity along and between the nanotubes; it may be also an indication of the challenges associated with carrying out chemical modification of nano-objects having high tendency to aggregate.

Injectable nanocomposites of single-walled carbon nanotubes and biodegradable polymers for bone tissue engineering.

We have investigated the dispersion of single-walled carbon nanotubes (SWNTs) and functionalized SWNTs (F-SWNTs) in the unsaturated, biodegradable polymer poly(propylene fumarate) (PPF) and examined the rheological properties of un-cross-linked nanocomposite formulations as well as the electrical and mechanical properties of cross-linked nanocomposites. F-SWNTs were produced from individual SWNTs by a diazonium-based method and dispersed better than unmodified SWNTs in both un-cross-linked and cross-linked PPF matrix. Cross-linked nanocomposites with F-SWNTs were superior to those with unmodified SWNTs in terms of their mechanical properties. Specifically, nanocomposites with 0.1 wt % F-SWNTs loading resulted in a 3-fold increase in both compressive modulus and flexural modulus and a 2-fold increase in both compressive offset yield strength and flexural strength when compared to pure PPF networks, whereas the use of 0.1 wt % SWNTs gained less than 37% mechanical reinforcement. These extraordinary mechanical enhancements considered together with Raman scattering and sol fraction measurements indicate strong SWNT-PPF interactions and increased cross-linking densities resulting in effective load transfer. With enhanced mechanical properties and capabilities of in situ injection and cross-linking, these SWNT/polymer nanocomposites hold significant implications for the fabrication of bone tissue engineering scaffolds.

Biocompatibility of native and functionalized single-walled carbon nanotubes for neuronal interface.

Single-walled carbon nanotubes (SWNTs) have unique mechanical, electrical, and optical properties and can be easily chemically modified; features that make them excellent candidate materials for applications as sensors and stimulators in neuronal tissue engineering. The purpose of this study was to demonstrate that SWNTs can support neuronal attachment and growth, that simple chemical modifications can be employed to control cell growth, that SWNTs do not interfere with ongoing neuronal function, and that neurons can be electrically coupled to SWNTs. Growth and attachment of the neuroblastoma*glioma NG108, a model neuronal cell, was assessed on unmodified SWNT substrates or substrates from SWNTs modified with 4-benzoic acid or 4-tert-butylphenyl functional groups using a simple functionalization method. SWNT films support cell growth, but at a reduced level compared to tissue culture-treated polystyrene. The order of viability and cell attachment was tissue culture treated polystyrene > SWNTs > 4-tert-butylphenyl-functionalized SWNTs > 4-benzoic acid-functionalized SWNTs. Decreased cell growth after culture on untreated (non adherent) polystyrene suggested that cell attachment was a critical determinant of proliferation and cell growth on SWNTs. Fluorescence and scanning electron microscopy revealed decreased neurite outgrowth in NG108 grown on SWNT substrates. We are also among the first groups to demonstrate electrical coupling of SWNTs and neurons by demonstrating that NG108 and rat primary peripheral neurons showed robust voltage-activated currents when electrically stimulated through transparent, conductive SWNT films. Our data suggest that SWNTs are flexible resource materials for tissue engineering application involving electrically excitable tissues such as muscles and nerves.

Functionalization density dependence of single-walled carbon nanotubes cytotoxicity in vitro.

The cytotoxic response of cells in culture is dependant on the degree of functionalization of the single-walled carbon nanotube (SWNT). After characterizing a set of water-dispersible SWNTs, we performed in vitro cytotoxicity screens on cultured human dermal fibroblasts (HDF). The SWNT samples used in this exposure include SWNT-phenyl-SO(3)H and SWNT-phenyl-SO(3)Na (six samples with carbon/-phenyl-SO(3)X ratios of 18, 41, and 80), SWNT-phenyl-(COOH)(2) (one sample with carbon/-phenyl-(COOH)(2) ratio of 23), and underivatized SWNT stabilized in 1% Pluronic F108. We have found that as the degree of sidewall functionalization increases, the SWNT sample becomes less cytotoxic. Further, sidewall functionalized SWNT samples are substantially less cytotoxic than surfactant stabilized SWNTs. Even though cell death did not exceed 50% for cells dosed with sidewall functionalized SWNTs, optical and atomic force microscopies show direct contact between cellular membranes and water-dispersible SWNTs; i.e. the SWNTs in aqueous suspension precipitate out and selectively deposit on the membrane.

Green chemical functionalization of single-walled carbon nanotubes in ionic liquids.

Single walled carbon nanotubes (SWNTs) are exfoliated and functionalized predominantly as individuals by grinding them for minutes at room temperature with aryldiazonium salts in the presence of ionic liquids (ILs) and K(2)CO(3). This constitutes an extremely rapid and mild green chemical functionalization process for obtaining the individualized nanotube structures. A number of ILs and various reaction conditions were surveyed. Raman, XPS, UV/vis/NIR spectroscopies, thermogravimetric analysis, and atomic force and transmission electron microscopies were used to characterize the products.

Rheological behaviour and mechanical characterization of injectable poly(propylene fumarate)/single-walled carbon nanotube composites for bone tissue engineering.

This work investigated the effects of the use of a surfactant or the functionalization of single-walled carbon nanotubes (SWNTs) on their dispersion in uncrosslinked poly(propylene fumarate) (PPF) and the mechanical reinforcement of crosslinked composites as a function of the SWNT concentration. Rheological measurements showed good dispersion of SWNTs in uncrosslinked PPF at low concentrations of 0.05 wt% and SWNT aggregation for higher concentrations for all formulations examined. Mechanical testing demonstrated significant reinforcement in the compressive and flexural mechanical properties of crosslinked nanocomposites which peaked for low SWNT concentrations of the order of 0.05 wt%. For example, a 74% increase was recorded for the compressive modulus and a 69% increase for the flexural modulus of nanocomposites with functionalized SWNTs at a 0.05 wt% loading. Nevertheless, this reinforcement was not related to the use of a surfactant or the functionalization of the SWNTs tested. Scanning electron microscopy examinations of fractured nanocomposite surfaces revealed the formation of SWNT aggregates at higher concentrations corroborating the rheological and mechanical data. These results suggest that the dispersion of individual SWNTs in a uncrosslinked formulation is pivotal to the development of injectable nanocomposites for bone tissue engineering applications.

Water-soluble, exfoliated, nonroping single-wall carbon nanotubes.

The scalable superacid solvent, radical-initiated aryldiazonium functionalization process produces individual SWNTs without the need for surfactant wrapping, centrifugation, or sonication. This work provides a facile pathway to aryl sulfonic acid-functionalized SWNTs that are not roped or bundled, and the functionalized nanotubes are water soluble.