3D-printed spine surgery implants: a systematic review of the efficacy and clinical safety profile of patient-specific and off-the-shelf devices

Three-dimensional printing (3DP), or additive manufacturing, is an emergent fabrication technology for surgical devices. As a production method, 3DP enables physical realisation of surgical implants from geometrically complex digital-models in computer-aided design. Spine surgery has been an innovative adopter of 3DP technology for both patient-specific (PS) and market-available ‘Off-The-Shelf’ (OTS) implants. The present study assessed clinical evidence for efficacy and safety of both PS and OTS 3DP spinal implants through review of the published literature. The aim was to evaluate the clinical utility of 3DP devices for spinal surgery. A systematic literature review of peer-reviewed papers featured on online medical databases evidencing the application of 3DP (PS and OTS) surgical spine implants was conducted in accordance with PRISMA guidelines. Twenty-two peer-reviewed articles and one book-chapter were eligible for systematic review. The published literature was limited to case reports and case series, with a predominant focus on PS designs fabricated from titanium alloys for surgical reconstruction in cases where neoplasia, infection, trauma or degenerative processes of the spine have precipitated significant anatomical complexity. PS and 3DP OTS surgical implants have demonstrated considerable utility for the surgical management of complex spine pathology. The reviewed literature indicated that 3DP spinal implants have also been used safely, with positive surgeon- and patient-reported outcomes. However, these conclusions are tentative as the follow-up periods are still relatively short and the number of high-powered studies was limited. Single case and small case series reporting would benefit greatly from more standardised reporting of clinical, radiographic and biomechanical outcomes. These slides can be retrieved under Electronic Supplementary Material.     

Use of augmented reality for image-guided spine procedures

European Spine Journal - Because of its ability to superimpose imaging data on a patient, while anchoring the user’s view to the immediate surroundings, augmented reality (AR) has the...     

Circulant orbitals for atoms and molecules

Circulant orbitals ϕ_n for a closed-shell system are the orbitals obtained when the N canonical orthonormal Hartree-Fock orbitals λ_[unk] are subjected to a unitary transformation which is the discrete Fourier transformation: ϕ_n = 1/√N Σ_[unk]λ_[unk]ω^{(n-1)([unk]-1)}, where ω = exp(2πi/N). Electron densities associated with the orbitals ϕ_n are each close to the average total electron density. The Fock matrix, diagonal for canonical orbitals, for circulant orbitals is a Hermitian circulant matrix, ε_{m, m+q} = 1/N Σ_[unk]ε_[unk]ω^q([unk]-1), where the ε_[unk] are the canonical orbital energies. The states ^Fϕ_n are uniformly distributed on the surface of a sphere in Hilbert space.     

Chemical potential, Teller's theorem, and the scaling of atomic and molecular energies

For atoms and homonuclear diatomic molecules, it is argued that the electronic energies have the forms [Formula: see text] and [Formula: see text] [Formula: see text], respectively,where Z is the atomic number, N is the number of electrons, and R is the internuclear distance. By using the Lieb-Simon theorem that the Thomas-Fermi theory is exact in the limit of large atomic number and the Teller theorem that molecules are not bound in the Thomas-Fermi theory, it is then shown, among other results, that the electron-electron repulsion energy for neutral systems has no term in Z² and that the nucleus-nucleus repulsion energy for neutral molecules is probably [unk](Z^5/3). For neutral atoms, it is predicted and verified that the chemical potential (electronegativity) is [unk](Z^-1/3) for large Z. Tetrahedral and octahedral molecules are briefly discussed.     

Hardness, softness, and the fukui function in the electronic theory of metals and catalysis.

The concepts of hardness eta = (2E/N2)nu and fukui function f(r) = [rho (r)/N]nu, which have recently been associated with the theory of chemical reactivity in molecules, are extended to the theory of metals. It is shown that at T = 0, 1/eta = g(epsilon F) and f(r) = g(epsilon F, r)/g(epsilon F), where g(epsilon F), and g(epsilon F, r) are the density of states and the local density of states, at the Fermi energy epsilon F. Softness S and local softness s(r) are defined as 1/eta and Sf(r), respectively, and it is shown that (formula; see text) where the averages are over a grand canonical ensemble. It is pointed out that the postulate that f(r) or g(epsilon F, r) determines site selectivity for metals in chemisorption and catalysis is synonymous with the recent argument by Falicov and Somorjai [Falicov, L. M. & Somorjai, G. A. (1985) Proc. Natl. Acad. Sci. USA 82, 2207-2211] that such selectivity is determined by low-energy density fluctuations.     

El valor de la MAPA y de los parámetros de lesión subclínica de órgano diana en el diagnóstico de hipertensión refractaria

Introduction

We aimed to assess the effectiveness of ambulatory blood pressure monitoring (ABPM) and subclinical target organ damage parameters for diagnosis of resistant hypertension (RH).

Abnormal pattern of gastric emptying of liquid in chronic duodenal ulcer

Gastric emptying was measured in 12 patients with chronic duodenal ulceration and compared with the results from 10 healthy volunteers. The test meal of 300 ml 15% dextrose, labelled with 99mTc-DTPA, was ingested in increments over 6 min. Gamma camera imaging proceeded over 30 min, with a 1-min frame time. A direct correction was applied for the fraction emptying into the small bowel during the ingestion period. Gastric emptying at 6 min was significantly greater in the group with duodenal ulcer (14.4 +/- 2.7% vs. 4.2 +/- 0.9%: mean +/- SEM, p less than 0.01). From this time onwards there were no significant differences in the rates of gastric emptying. These results suggest that chronic duodenal ulcer is associated with an abnormal pattern of gastric emptying of liquid, characterised by an initial rapid phase.     

Detection and quantification of synthetic cathinones and selected piperazines in hair by LC-MS/MS

New psychoactive substances (NPS)—such as synthetic cathinones and piperazines—are defined as substances designed to replicate the effects of traditional illegal drugs, including cocaine, ecstasy and amphetamines. These substances are known to potentially be much more potent than their analogs. In the past, there were many poisonings and deaths associated with NPS. Because of this, NPS identification and quantification have become more important in forensic toxicology. The present work aimed to develop, validate and apply a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method capable of detecting 35 synthetic cathinones and piperazines in hair samples. All target analytes were resolved in a 12 min run time and identified based on the quantifier ion, at least one product ion and the retention time. Depending on the analyte, the calibration curves were linear over a maximal range of 0.01–3 ng/mg. The limits of detection and quantification were within the ranges of 0.006–0.052 ng/mg and 0.008–0.095 ng/mg, respectively. The precision, bias and matrix effect were all within acceptable GTFCh thresholds and the method was free from interferences. The validated method was successfully used to identify synthetic cathinones and piperazines in authentic hair samples (n = 40) from forensic cases, demonstrating its suitability for the screening and quantification of a wide number of new stimulants in hair specimens.     

Successful Aortic Valve Replacement Surgery in a Patient with Severe Haemophilia a with Low Titre Inhibitor

Acute leukemia, secondary myelodysplasia and paroxysmal nocturnal hemoglobinuria evolving from severe aplastic anemia (AA) following immunosuppressive therapy are well recognized. However, severe AA occurring after complete remission of acute promyelocytic leukemia (APL) has been documented only once in 2009. We report a case of 30-year-old male diagnosed with APL who achieved complete cytogenetic remission with all-trans retinoic acid based induction regimen and developed severe AA few months later during maintenance therapy.