Salvage of failed direct lateral sacroiliac joint fixation using a new percutaneous lateral-oblique transfixation technique with two variable-threaded screws: a multicenter case report of three cases.

Background: The direct lateral trans-gluteal muscle splitting transiliac approach was popularized to fixate the sacroiliac joint (SIJ) using three cannulated triangular titanium implants (TTIs) wedges. Publications support efficacy of the direct lateral approach but a paucity of literature to help surgeons revise these implants when they fail. Intuitively the implants can be removed but require an open incision and dissection through the gluteal muscles and scar tissue which can lead to muscle and neurovascular injuries. Our objective was to evaluate the clinical outcome, measured by patient-reported Visual Analog Score (VAS), of three patients who had failed direct lateral SIJ fusions each using three implants and describe a revision technique using a new percutaneous lateral-oblique transfixation technique with two variable-threaded screws while preserving the original implants. Case Description: Two separate orthopedic spine surgeons at different hospitals performed the technique using two SacroFuse® screws for SIJ revision fusion in three patients who had clinical symptoms and radiographic findings of SIJ pseudoarthrosis after direct lateral approach. One 61 years old male patient had a previous surgery with three lateral threaded screw implants. Two females with ages 47 and 40 years old had three TTI wedges. Follow-up from 10 to 26 months. Patients discharged home the same day. Mean procedure time of 20 minutes with blood loss less than five cc. Incision size was approximately 1 inch. Each patient had a 12 mm × 60 mm and a 12 mm × 50 mm screw filled with NanoFuse Biologics synthetic bioactive glass and demineralized bone matrix. Prior implants were left in place. There was an 89% decrease in mean VAS score of 9.5 to 1. Conclusions: This is a clinically valuable report because until now there was no reconstructive surgery to revise direct lateral implants other than removal with potential neurovascular risks. This is the first article to demonstrate a lateral-oblique transfixation technique with two variable-threaded screws for successful salvage of SIJ pseudoarthrosis after direct lateral fixation without implant removal. The Sacrix technique achieved immediate stability and long-term fusion documented on computed tomography (CT) scan as early as 6 months.

Effect of isopropyl side chain branching and different anions on electronic structure, vibrational spectra, and hydrogen bonding of isopropyl-imidazolium-based ionic liquids: Experimental and theoretical investigations.

In the present work, four branched methylated, 1,2-dimethyl-3-isopropyl-imidazolium (i-[C3Dmim+]) and protonated,1-methyl-3-isopropyl-imidazolium (i-[C3mim+])-based ionic liquids (ILs) with varying anion (Br-, BF4-, PF6-, and NTf2-) were synthesized and investigated by NMR, infrared (IR) and Raman spectroscopy. Based on infrared and Raman spectroscopy, complete vibrational assignments have been performed. The IR and Raman analysis revealed that the vibrational spectra are virtually unaffected upon methylation, while significant frequency changes were observed by changing anion. Furthermore, to determine the electronic structure, energetic stability, and vibrational properties of these i-[C3Dmim]Y, i-[C3mim]Y (Y = Br, BF4, PF6, and NTf2) ion pairs, quantum chemical calculations including the dispersion correction method are performed both on single ions and on ionic couples. The calculated electron density was analyzed to expose non-covalent intra- and interionic interactions by the quantum theory of atoms in molecules (AIM) and interpreted in terms of both anion dependence and type of interaction. Computational results suggest that for all ionic couples the most energetically stable configuration is obtained with the anions located close to the C2 position of the imidazolium cation. However, in the case of i-[C3mim]NTf2 and i-[C3Dmim]BF4, similar energies were obtained in configurations 2 and 3 where the anion is located above the imidazolium ring. For i-[C3mim]Br a stronger hydrogen bond is predicted than for other studied ILs. Calculations indicate that a red shift of the CH stretching bands should occur due to hydrogen bonding; indeed, such displacement of bands is experimentally observed.

Strong-field ionization of CH3Cl: proton migration and association.

Strong-field ionization of CH3Cl using femtosecond laser pulses, and the subsequent two-body dissociation of CH3Cl2+ along Hn+ (n = 1-3) and HCl+ forming pathways, have been experimentally studied in a home-built COLTRIMS (cold target recoil ion momentum spectrometer) setup. The single ionization rate of CH3Cl was obtained experimentally by varying the laser intensity from 1.6 × 1013 W cm-2 to 2.4 × 1014 W cm-2 and fitted with the rate obtained using the MO-ADK model. Additionally, the yield of Hn+ ions resulting from the dissociation of all charge states of CH3Cl was determined as a function of intensity and pulse duration (and chirp). Next, we identified four two-body breakup pathways of CH3Cl2+, which are H+ + CH2Cl+, H2+ + CHCl+, H3+ + CCl+, and CH2+ + HCl+, using photoion-photoion coincidence. The yields of the four pathways were found to decrease on increasing the intensity from I = 4.2 × 1013 W cm-2 to 2I = 8.5 × 1013 W cm-2, which was attributed to enhanced ionization of the dication before it can dissociate. As a function of pulse duration (and chirp), the Hn+ forming pathways were suppressed, while the HCl+ forming pathway was enhanced. To understand the excited state dynamics of the CH3Cl dication, which controls the outcome of dissociation, we obtained the total kinetic energy release distributions of the pathways and the two-dimensional coincidence momentum images and angular distributions of the fragments. We inferred that the Hn+ forming pathways originate from the dissociation of CH3Cl dications from weakly attractive metastable excited states having a long dissociation time, while for the HCl+ forming pathway, the dication dissociates from repulsive states and therefore, undergoes rapid dissociation. Finally, quantum chemical calculations have been performed to understand the intramolecular proton migration and dissociation of the CH3Cl dication along the pathways mentioned above. Our study explains the mechanism of Hn+ and HCl+ formation and confirms that intensity and pulse duration can serve as parameters to influence the excited state dynamics and hence, the outcome of the two-body dissociation of CH3Cl2+.

Stereotactic Ventriculostomy Guide.

Introduction Based on the anatomy of the frontal horn, a stereotactic ventriculostomy guidance system that does not need an elaborate setup and is suitable for ventricles of all sizes was developed. The objective of this paper is to describe this system and present the results of a cadaveric study in which this system was used. Method The system has a midline-based plate that is contoured to snugly fit the top of the head. It has two probe holders, one on each side at pre-set angles in coronal and sagittal planes, which enables the probe holders to point at the foramen of Monro. A cadaver study was done on eight donors. First, using the guidance system a 1.4 mm endoscope was inserted into the right frontal horn through a twist drill hole. Next, the scope was inserted into the right frontal horn on the same donors using the freehand method. Result With the guide, all eight ventricles were entered into on the first trial, and the foramen of Monro was visible end-on. With freehand technique: six ventricles were entered on the first try; however, the foramen of Monro was visible end-on only in one. In the other two, two to three attempts were needed. The guide facilitated 100% visibility for the end-on visibility of the foramen of Monro upon insertion and the results were statistically significant with t=7, df=7, p-value=0.000106. Conclusion This is a simple system, which is easy to use. The cadaveric study showed a high degree of accuracy to access the ventricles. The data shows significant improvement compared to the freehand technique.

A comprehensive multidisciplinary investigation on CO2 capture from diesel engine.

Climate change and global warming are the visible consequences of the increased amount of carbon dioxide (CO2) in the atmosphere. Among the various sources of anthropogenic CO2 emission, the diesel engine has a significant contribution. The development of a reliable system to efficiently minimize CO2 emissions from diesel engines to the safest level is lacking in the open literature. Therefore, a comprehensive multidisciplinary approach has been applied in this paper to investigate the efficacy of the post-combustion carbon capture (PCC) process for the diesel engine. The experiments have been performed on the exhaust of a direct injection diesel engine at five different brake powers with blends of aqueous ammonia (AQ_NH3), monoethanolamine (MEA), N,N-dimethylethanolamine (DMEA), and 1-ethyl-3-methylimidazolium tetrafluoroborate (C2mim BF4) ionic liquid (IL) as an absorbent for CO2 capture. The reaction mechanism of these absorbent with CO2 are also studied by the geometrical, energetical, MESP, frontier molecular orbitals, and NBO analysis using the first-principles density functional theory (DFT) calculations. The maximum CO2 absorption efficiency of almost 97% was achieved for the blend consisting of 67% of AQ_NH3 and 33% of MEA. Moreover, AQ_MEA and blend of AQ_NH3, DMEA, and C2mim BF4 ionic liquid showed 96% and 94% CO2 absorption efficiency, respectively.

Effectiveness of a Fully Impregnated Hydroxyapatite Polyetheretherketone Cage on Fusion in Anterior Cervical Spine Surgery.

Introduction Anterior cervical discectomy and fusion (ACDF) is the gold standard for the treatment of cervical spondylosis. However, new techniques, technologies, and improved implants have aided surgeons in reducing operative time with enhanced patient outcomes. Impregnated hydroxyapatite polyetheretherketone (HA PEEK) cages (Arena-C HA®, LESspine Inc. Malden, MA) are one such option that has aimed to increase the fusion rate. The authors herein aimed to assess the use of HA PEEK interbody cages by looking at outcomes, complications, and radiographic fusion.  Methods The medical records of 41 consecutive patients undergoing single-level ACDF with impregnated HA PEEK cages (group 1) were compared to the control group of 47 patients who had single-level ACDF without impregnated HA PEEK cages (group 2). Outcomes assessed included Visual Analog Scale (VAS) neck, Neck Disability Index (NDI) scores, radiographic fusion, and complication rates.  Results Of the 41 patients in group 1 (HA PEEK), 48% were female population with a mean age of 58.5+/- 1.7 years and BMI 29.7+/-1.2 kg/m2. Of the 47 patients in group 2 (non-HA PEEK), 53% were female with a mean age of 54.3+/- 1.2 years and BMI 27.8+/-0.8 kg/m2. Using t-test, there was a statistically significant intergroup difference in two-year VAS neck and NDI scores, p=0.007, and p=0.001, respectively. Radiographic fusion occurred as early as three months in the HA PEEK group.  Conclusions This study has demonstrated the equivalence of impregnated HA PEEK cages in single-level ACDF. Significant improvements were seen in VAS and NDI scores in the HA PEEK group. There was no incidence of heterotopic bone formation or reaction to HA PEEK cages. Additionally, a trend toward fusion was seen in HA PEEK patients as early as three to five months compared to seven to eight months for the ACDF group. We conclude that HA PEEK cages can be safely placed with excellent outcomes. However, further studies are required to look at added benefits.

CT Scan and Clinical Outcomes of Novel Lateral-Oblique Percutaneous Sacroiliac Joint (SIJ) Fixation: Technique and Literature Review.

Purpose The sacroiliac joint (SIJ) is estimated to be a source of pain in 15%-30% of patients presenting for the evaluation of low back pain. The SIJ may develop symptoms in an estimated 43% of patients who have had previous lumbar fusion surgeries. With increased awareness of SIJ as a pain source and for those patients who have intractable pain and who fail nonoperative treatment, surgery to stabilize the SIJ is becoming more common. Thus multiple different technologies and techniques need to be evaluated. The purpose of this study is to report on the clinical and radiographic follow-up of percutaneous lateral-oblique sacroiliac joint fusion with a threaded compression screw performed in an outpatient ambulatory surgery center (ASC). Methods Three consecutive patients were chosen for this technique, and after completion, were followed for at least 24 months as part of a pilot study to see how they responded to the treatment. The medical charts of these patients were reviewed along with follow-up radiographs and computed tomography (CT) scans to assess for radiographic fusion designated as bridging bone across the SIJ with no signs of implant loosening such as haloes around the screws, change in position, or screw breakage. The SacroFuse (Sacrix LLC, Boston, MA) SIJ screws were 12 mm x 60 mm at S1 and 12 mm x 50 mm at S2 with threads for compressive fixation and cannulated for percutaneous placement over a guidewire. We evaluated patients' demographics, the pain visual analog scale (VAS) score, and the Oswestry Disability Index (ODI) preoperatively and postoperatively. Results Our first patient was a 51-year-old male body mass index (BMI) 33.3 kg/m2 with a previous lumbar fusion. He underwent a two-staged SIJ fusion. The first surgery was done as an open direct lateral surgery, and the second stage was performed three months later using a direct percutaneous lateral-oblique technique for three months. The second and third patients, respectively, were 22-year-old female status prior L5-S1 anterior lumbar interbody fusion (ALIF) plus right posterior unilateral pedicle screws. She had a BMI of 38.3 kg/m2. The third patient was a 41-year-old male with a BMI of 29.5 kg/m2 who underwent lateral-oblique bilateral percutaneous SIJ fixation. The latest CT imaging of each patient demonstrated increased bone density adjacent and within implants with intra-articular osseous bridging. There were no implant failures or complications. Conclusion This pilot study demonstrated the feasibility and effectiveness of a new percutaneous lateral-oblique SIJ fusion technique with a threaded compression screw done safely in an ASC. Patients demonstrated early pain relief and long-term fusion of their SIJ. We introduced the Sacrix line as a key fluoroscopic landmark for the success of this percutaneous technique.

Sequential and cellular detection of copper and lactic acid by disaggregation and reaggregation of the fluorescent panchromatic fibres of an acylthiourea based sensor.

We report, for the first time, the self-assembly of an acyl-thiourea based sensor, N-{(6-methoxy-pyridine-2-yl) carbamothioyl}benzamide (NG1), with panchromatic fluorescent fibres and its dual-sensing properties for the sequential detection of Cu2+ ions and lactic acid. The panchromatic fibres formed by NG1 were disrupted in the presence of Cu2+ ions and this was accompanied by a visible colour change in the solution from colourless to yellow. The addition of lactic acid to the NG1 + Cu2+ solution, on the other hand, induced re-aggregation to fibrillar structures and the colour of the solution again changed to colourless. Hence, it may be surmised that the disaggregation and re-aggregation impart unique dual-sensing properties to NG1 for the sequential detection of Cu2+ ions and lactic acid. The application of NG1 as a selective sensor for Cu2+ ions and lactic acid has been assessed in detail by UV-visible and fluorescence spectroscopy. Furthermore, two structural variants of NG1, namely, NG2 and NG3, were synthesized, which suggest the crucial role of pyridine in imparting panchromatic emission properties and of both pyridine and acyl-thiourea side chain in the binding of Cu2+ ions. The O-methoxy group plays an important part in making NG1 the most sensitive probe of its structural analogs. Finally, the utility of NG1 for the sequential and cellular detection of Cu2+ ions and lactic acid was studied in human RPE cells. The experimental results of the interaction of NG1 with Cu2+ ions and lactic acid have also been validated theoretically by using quantum chemical calculations based on density functional theory (DFT). To the best of our knowledge, this is the first report wherein a dual sensor for Cu2+ ions and lactate ions is synthesized. More importantly, the aggregation properties of the sensor have been studied extensively and an interesting correlation of the photophysical properties of the probe with its self-assembling behavior has been elucidated.

Hybrid Structure of Ionic Liquid and TiO2 Nanoclusters for Efficient Hydrogen Evolution Reaction.

Hydrogen energy has received significant attention in the renewable energy sector due to its high energy density and environmentally friendly nature. For the efficient hydrogen generation from water, the hydrogen evolution reaction (HER) has to be optimized, which requires a highly efficient electrocatalyst. In this work, a hybrid structure of the ionic liquid (IL) 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (C2mim TfO) and (TiO2)n nanoclusters with n = 2-12 has been investigated in the pursuit of new catalyst materials for effective HER. We have employed state-of-the-art density functional theory (DFT) computations to depict the HER catalytic performance of IL/(TiO2)n hybrid systems through Gibbs free energy (ΔG) and an exchange-current-based "volcano" plot. We have explored the effect of the TiO2 nanoclusters on the structural and electronic characteristics of the IL, calculating the adsorption energy, the energies of the highest occupied (HOMO) and lowest unoccupied molecular orbitals (LUMO), the HOMO-LUMO band gap Eg, and the work function ϕ. The variation in size of the TiO2 nanocluster in the IL/(TiO2)n hybrid system was found to have a significant influence on the electronic properties. The obtained results suggest that the ΔG of the hydrogen adsorption is remarkably close to the ideal value (0 eV) for the IL/(TiO2)5 system, which also reflects from the volcano plot, suggesting that this complex is the best HER catalyst among the studied systems; it might be even better than the traditional Pt-based catalyst. Thus, the present work suggests ways for the experimental realization of low-cost and multifunctional IL-based hybrid catalysts for clean and renewable hydrogen energy production.

Strong-field ionization of polyatomic molecules: ultrafast H atom migration and bond formation in the photodissociation of CH3OH.

Strong-field ionization induces various complex phenomena like bond breaking, intramolecular hydrogen migration, and bond association in polyatomic molecules. The H-atom migration and bond formation in CH3OH induced by intense femtosecond laser pulses are investigated using a Velocity Map Imaging (VMI) spectrometer. Various laser parameters like intensity (1.5 × 1013 W cm-2-12.5 × 1013 W cm-2), pulse duration (29 fs and 195 fs), wavelength (800 nm and 1300 nm), and polarization (linear and circular) can serve as a quantum control for hydrogen migration and the yield of Hn+ (n = 1-3) ions which have been observed in this study. Further, in order to understand the ejection mechanism of the hydrogen molecular ions H2+ and H3+ from singly-ionized CH3OH, quantum chemical calculations were employed. The dissociation processes of CH3OH+ occurring by four dissociative channels to form CHO+ + H3, H3+ + CHO, CH2+ + H2O, and H2O+ + CH2 are studied. Using the combined approach of experiments and theory, we have successfully explained the mechanism of intramolecular hydrogen migration and predicted the dissociative channels of singly-ionized CH3OH.

Inter Spinal Fixation and Stabilization Device for Lumbar Radiculopathy and Back Pain.

INTRODUCTION: Generally, interspinal distractor fixation devices are used for severe low back pain associated with neurogenic claudication, and radiculopathy with central or lateral recess stenosis and/or foraminal narrowing. In this paper, the authors result in cases of severe low back pain and lumbar radiculopathy in whom this device was used with excellent results. METHOD: This is a retrospective study. Patients were contacted via phone call and their pain score and other data were recorded at different timelines. The final data presented in this paper are the data collected at the final follow-up that ranges from 14 months to 24 months. Surgeries were performed in the outpatient setting and although no identifiable patient information is included in this paper, yet, patients were asked for their verbal consent. The patient data are only included if verbal consent was obtained. RESULTS: Over the past 24 months, 13 patients with disc protrusion and/or central and/or foraminal spinal stenosis were treated with this procedure. Follow-up ranges from 14 months to 24 months with a median of 19 months, male/female ratio of 6/7, and a median age of 68 years. There were no complications or reoperation. Statistical analysis showed significant improvement in the Numeric Pain Rating Scale (NPRS) for back and radicular leg pain (p-value = 0.000552 for back pain and p-value = 0.000291 for radicular leg pain). CONCLUSION: The system reported in this paper is a solid fixation system that works both as a distractor and internal decompressor of the spinal canal. It is simple to use and safe. Though the number of patients is small, statistically significant improvement was reported at a median follow-up of 19 months.

Impact of alkyl chain length and water on the structure and properties of 1-alkyl-3-methylimidazolium chloride ionic liquids.

The influence of the length of the alkyl chain and water molecules on the hydrogen-bond interaction of the chloride anion and imidazolium-based cation of the ionic liquid (IL) Cnmim Cl (where n = 2, 4, 6, 8, and 10) was investigated by combining attenuated total internal reflection infrared (ATR-IR) spectroscopy and density functional theory (DFT) calculations. Here, for the first time, the conformational isomerism of the alkyl chain of Cnmim Cl (n = 2, 4, 6, 8, and 10) is identified by marker IR bands. The IR peak at 1470 cm-1 related to the alkyl chain vibration exhibits a significant perturbation in its intensity and further shows a red shift upon increasing alkyl chain length. This indeed might be a marker IR band for conformational isomerism and also an indication of the interaction of the alkyl chain with the chloride anion. Further, in the C-H vibration region of the IR spectra, a significant variation of the IR intensities was observed for the νs(CH2) and νas(CH2-CH3) modes at 2931 and 2976 cm-1, respectively. These bands can be considered as further markers for conformational isomerism of the alkyl chain. Moreover, the peak at 2976 cm-1 assigned to an alkyl chain vibration reveals the maximum red shift of 20 cm-1 for n = 10, which suggests charge redistribution among ion-pairs as a result of the alkyl chain variations. Noticeably, the C2-H vibration does not show any significant change of its wavenumber position, suggesting that the alkyl chain length does not interfere with the hydrogen bond interaction between C2-H and the Cl anion. This was also evident from the DFT-calculated bond strength between C2-H and Cl, which remains unchanged upon varying the alkyl chain length. In aqueous solutions, blue shifts of the v(C2-H) band by +65, +60, +67, +62 and +62 cm-1 for Cnmim Cl (n = 2, 4, 6, 8, and 10) are observed, respectively. These results point to a weakening of the hydrogen bond between cation and anion, which is also supported and validated by results of the solvent (water) effect obtained using the polarized continuum model (PCM) of the DFT calculations.

Impact of Size and Electronegativity of Halide Anions on Hydrogen Bonds and Properties of 1-Ethyl-3-methylimidazolium-Based Ionic Liquids.

The effect of the anion size and electronegativity of halide-based anions (Cl-, Br-, I-, and BF4-) on the interionic interaction in 1-ethyl-3-methylimidazolium-based ionic liquids (ILs) C2mim X (X = Cl, Br, I, and BF4) is studied by a combined approach of experiments (Raman, IR, UV-vis spectroscopy) and quantum chemical calculations. The fingerprint region of the Raman spectra of these C2mim X ion-pairs provides evidence of the presence of the conformational isomerism in the alkyl chain of the C2mim+ cation. The Raman and IR bands of the imidazolium C2-H stretch vibration for C2mim X (X = Cl, Br, I, and BF4) were noticeably blue-shifted with the systematic change in size of anions and the electronegativity. The observed blue shift in the C2-H stretch vibration follows the order C2mim BF4 > C2mim I > C2mim Br > C2mim Cl, which essentially indicates the strong hydrogen bonding in the C2mim Cl ion-pair. DFT calculations predict at least four configurations for the cation-anion interaction. On the basis of relative optimized energies and basis-set-superposition-error (BSSE) corrected binding energies for all ion-pair configurations, the most active site for the anion interaction was found at the C2H position of the cation. Besides information about the C2H position, our DFT results give insights into the anion interaction with the ethyl and methyl chain of the cation, which was also confirmed experimentally [ Chem. Commun. 2015 , 51 , 3193 ]. The anion interaction at the C2H site of the cation favors a planar geometry in C2mim X for X = Cl, Br, and I; however, for BF4, the system prefers a nonplanar geometry where the anion is located over the imidazolium ring. TD-DFT results were used to analyze the observed UV-vis absorption spectra in a more adequate way giving insights into the electronic structure of the ILs. Overall, a reasonable correlation between the observed and the DFT-predicted results is established.