3D printing in fracture treatment : Current practice and best practice consensus.

The use of 3D printing in orthopedic trauma is supported by clinical evidence. Existing computed tomography (CT) data are exploited for better stereotactic identification of morphological features of the fracture and enhanced surgical planning. Due to complex logistic, technical and resource constraints, deployment of 3D printing is not straightforward from the hospital management perspective. As a result not all trauma surgeons are able to confidently integrate 3D printing into the daily practice. We carried out an expert panel survey on six trauma units which utilized 3D printing routinely. The most frequent indications are acetabular and articular fractures and malalignments. Infrastructure and manpower structure varied between units. The installation of industrial grade machines and dedicated software as well as the use of trained personnel can enhance the capacity and reliability of fracture treatment. Setting up interdisciplinary jointly used 3d printing departments with sound financial and management structures may improve sustainability. The sometimes substantial logistic and technical barriers which impede the rapid delivery of 3D printed models are discussed.

[3D printing in fracture treatment : Current practice and best practice consensus]. / 3D-Druck in der Frakturversorgung : Aktuelle Praxis und "Best-practice"-Konsens.

The use of 3D printing in orthopedic trauma is supported by clinical evidence. Existing computed tomography (CT) data are exploited for better stereotactic identification of morphological features of the fracture and enhanced surgical planning. Due to complex logistic, technical and resource constraints, deployment of 3D printing is not straightforward from the hospital management perspective. As a result not all trauma surgeons are able to confidently integrate 3D printing into the daily practice. We carried out an expert panel survey on six trauma units which utilized 3D printing routinely. The most frequent indications are acetabular and articular fractures and malalignments. Infrastructure and manpower structure varied between units. The installation of industrial grade machines and dedicated software as well as the use of trained personnel can enhance the capacity and reliability of fracture treatment. Setting up interdisciplinary jointly used 3d printing departments with sound financial and management structures may improve sustainability. The sometimes substantial logistic and technical barriers which impede the rapid delivery of 3D printed models are discussed.

Microdamage generation by tapered and cylindrical mini-screw implants after pilot drilling.

OBJECTIVE: To investigate the relationship between mini-screw implant (MSI) diameter (1.6 vs 2.0 mm) and shape (tapered vs cylindrical) and the amount of microdamage generated during insertion. MATERIALS AND METHODS: Thirty-six cylindrical and 36 tapered MSIs, 6 mm long, were used in this study. Half of each shape was 1.6 mm in diameter, while the other half was 2.0 mm. After pilot drilling, four and five MSIs were inserted, respectively, into fresh cadaveric maxillae and mandibles of dogs. Bone blocks containing the MSIs were sectioned and ground parallel to the MSI axis. Epifluorescent microscopy was used to measure overall cortical thickness, crack length, and crack number adjacent to the MSI. Crack density and total microdamage burden per surface length were calculated. Three-way analysis of variance (ANOVA) was used to test the effects of jaw, and MSI shape and diameter. Pairwise comparisons were made to control the overall significance level at 5%. RESULTS: The larger (2.0 vs 1.6 mm) cylindrical MSIs increased the numbers, lengths, and densities of microcracks, and the total microdamage burden. The same diameter cylindrical and tapered MSIs generated a similar number of cracks and crack lengths. More total microdamage burden was created by the 2.0-mm cylindrical than the 2.0-mm tapered MSIs. Although higher crack densities were produced by the insertion of 1.6-mm tapered MSIs, there was no difference in total microdamage burden induced by 1.6-mm tapered and 1.6-mm cylindrical MSIs. CONCLUSIONS: Pilot drilling is effective in reducing microdamage during insertion of tapered MSIs. To prevent excessive microdamage, large diameter and cylindrical MSIs should be avoided.

High-resolution imaging of the intramolecular structure of indomethacin-carrying dendrimers by scanning tunneling microscopy.

Dendrimers have shown great potential in drug delivery because of their enhancement of drug solubility in aqueous media, leading to an increase in in vivo circulation and efficacy to targets. The structure of drug-dendrimer complexes however, is not well-known owing to the difficulties associated with visualizing individual drug molecules attached to dendrimers. Scanning tunneling microscopy (STM) enables visualization of dendrimer intramolecular structures using our approach of metal ion tagging. This work extends the approach to reveal the hierarchical structure of indomethacin-loaded poly(amidoamine) hydroxyl-terminated dendrimers. STM imaging provides structural information such as their height, lateral dimensions, and volume. High-resolution STM images enable the identification and count of individual indomethacin molecules bound to the anterior of dendrimers. Removal of drug molecules by the STM tip allows the calculation of individual drug-dendrimer binding energy, which is consistent with 1-3 hydrogen bonds. These investigations provide new insight into the hierarchical structure and nature of indomethacin-dendrimer interactions and deepen our understanding of the stability and pharmacokinetic behavior of dendrimer-based drug delivery vehicles.

Current use of dietary supplementation in patients with age-related macular degeneration.

BACKGROUND: The Age-Related Eye Disease Study (AREDS) Research Group recently reported significant reduction in the progression of certain categories of age-related macular degeneration (AMD) with the use of high-dose antioxidant and zinc supplementation. We studied the current use of dietary supplementation in our patients with AMD to determine whether dosages recommended in the AREDS were being achieved. We also evaluated the easiest and most cost-effective method to reach recommended dosages using supplements currently available in Canada. METHODS: Cross-sectional descriptive study conducted by patient survey from Feb. 1 to Mar. 31, 2002. All patients with the diagnosis of AMD were surveyed during an office visit at a retinal specialty clinic in Edmonton. The following information was collected: demographic information, duration of AMD, smoking status and current use of dietary supplements. For patients using supplements, we also noted duration of use, reason for use, who recommended use, and type and dosage of supplements (including vitamin, mineral and herbal supplements). The exact dosages were confirmed by follow-up telephone interview. Cost estimates were determined by averaging retail prices from several local pharmacies. We compared methods of reaching the recommended dosages using various combinations of commercially available multivitamin formulations and individual beta-carotene, vitamin C and E, and zinc supplements. The goal was to match the dosage recommended in the AREDS (without exceeding it if possible) at maximum convenience and minimum cost and without increasing the risk of toxic effects. RESULTS: Of 108 patients with AMD surveyed, 85 (79%) were taking dietary supplements, and 73 (68%) were taking at least one AREDS ingredient. The mean dosages of beta-carotene, vitamins C and E, and zinc were all below those recommended in the AREDS. None of our patients met the recommended dosages for all four ingredients. We identified four methods of reaching recommended dosages using various combinations of ICAPS TR, Ocuvite and Vitalux as well as Centrum multivitamin and individual supplements. INTERPRETATION: Patients with AMD may not be receiving the dosages of beta-carotene, vitamins C and E, and zinc recommended in the AREDS. Until new formulations of high-dose antioxidant and zinc supplements are available in Canada, patients should be counselled to attempt to meet recommended dosages by using combinations of currently available supplements.