Size selection and placement of pedicle screws using robot-assisted versus fluoroscopy-guided techniques for thoracolumbar fractures: possible implications for the screw loosening rate.

BACKGROUND: There has been increased development of robotic technologies for the accuracy of percutaneous pedicle screw placement. However, it remains unclear whether the robot really optimize the selection of screw sizes and enhance screw stability. The purpose of this study is to compare the sizes (diameter and length), placement accuracy and the loosening rate of pedicle screws using robotic-assisted versus conventional fluoroscopy approaches for thoracolumbar fractures. METHODS: A retrospective cohort study was conducted to evaluate 70 consecutive patients [34 cases of robot-assisted percutaneous pedicle screw fixation (RAF) and 36 of conventional fluoroscopy-guided percutaneous pedicle screw fixation (FGF)]. Demographics, clinical characteristics, and radiological features were recorded. Pedicle screw length, diameter, and pedicle screw placement accuracy were assessed. The patients' sagittal kyphosis Cobb angles (KCA), anterior vertebral height ratios (VHA), and screw loosening rate were evaluated by radiographic data 1 year after surgery. RESULTS: There was no significant difference in the mean computed tomography (CT) Hounsfield unit (HU) values, operation duration, or length of hospital stay between the groups. Compared with the FGF group, the RAF group had a lower fluoroscopy frequency [14 (12-18) vs. 21 (16-25), P < 0.001] and a higher "grade A + B" pedicle screw placement rate (96.5% vs. 89.4%, P < 0.05). The mean screw diameter was 6.04 ± 0.55 mm in the RAF group and 5.78 ± 0.50 mm in the FGF group (P < 0.001). The mean screw length was 50.45 ± 4.37 mm in the RAF group and 48.63 ± 3.86 mm in the FGF group (P < 0.001). The correction loss of the KCA and VHR of the RAF group was less than that of the FGT group at the 1-year follow-up [(3.8 ± 1.8° vs. 4.9 ± 4.2°) and (5.5 ± 4.9% vs. 6.4 ± 5.7%)], and screw loosening occurred in 2 out of 34 patients (5.9%) in the RAF group, and 6 out of 36 patients (16.7%) in the FGF group, but there were no significant differences (P > 0.05). CONCLUSION: Compared with the fluoroscopy-guided technique, robotic-assisted spine surgery decreased radiation exposure and optimizes screw trajectories and dimensions intraoperatively. Although not statistically significant, the loosening rate of the RAF group was lower that of than the FGT group.

A new method for establishing operative channels in unilateral biportal endoscopic surgery: Technical notes and preliminary results.

BACKGROUND: The unilateral biportal endoscopic (UBE) technique has been widely used in spine surgery. At present, a traditional rigid working channel is available for the UBE system. A metal semicircular canal is located in the working channel. However, due to the metal material of the working channel, arthroscopy and instruments are constrained from moving in UBE surgery. Additionally, an assistant is needed during the procedure to hold the traditional working channel. OBJECTIVE: For simplicity of operation and convenient movement of the arthroscopy and instrument, we describe a new method for establishing operative channels in UBE surgery. METHODS: We retrospectively reviewed 50 patients who underwent unilateral biportal endoscopic discectomy (UBED) from February 2020 to August 2020 via our new method. The Oswestry Disability Index (ODI) and visual analogue scale (VAS) score were measured preoperatively and 1 month, 3 months, 6 months and 12 months postoperatively. Statistical comparisons were made using analysis of covariance and paired t tests. RESULTS: The VAS scores for back pain at the five time points were 5.20 ± 2.57, 1.96 ± 0.95, 1.50 ± 0.84, 1.64 ± 1.08 and 1.18 ± 0.39. The leg pain VAS scores were 7.02 ± 2.25, 2.02 ± 1.27, 1.48 ± 0.89, 1.32 ± 0.79 and 0.88 ± 0.52. The ODI values were 51.08 ± 19.97, 19.62 ± 15.51, 8.26 ± 7.40, and 7.54 ± 6.42 to 3.24 ± 1.10. The postoperative ODIs and VAS scores of low back pain and leg pain were significantly lower than those before surgery, and differences were statistically significant (all p< 0.05). The pressure of the closed outflow was significantly higher than that of the open outflow (37.35 ± 13.11 mm Hg vs. 24.55 ± 12.64 mm Hg p= 0.003). After we tightened the infusion strap to open the outflow, the pressure decreased significantly (26.4 ± 14.08 mm Hg vs. 37.35 ± 13.11 mm Hg p= 0.015). There were 2 cases of complications, including 1 case of postoperative recurrence and 1 case of dural tears. CONCLUSION: This study demonstrates the technical feasibility, safety, and efficacy of modified channel establishment in UBE surgery.

Titanium-coated PEEK Versus Uncoated PEEK Cages in Lumbar Interbody Fusion: A Systematic Review and Meta-analysis of Randomized Controlled Trial.

STUDY DESIGN: Systematic review and meta-analysis. OBJECTIVE: This study was performed to compare the fusion and subsidence rate of titanium-coated polyetheretherketone (Ti-PEEK) versus polyetheretherketone (PEEK) cages after lumbar fusion and to investigate the clinical effect on patient-reported outcomes (PROMs). SUMMARY OF BACKGROUND DATA: Ti-PEEK cages have been developed to combine the advantages of both titanium alloy and PEEK, but whether they are superior to uncoated PEEK cages in bone fusion is still inconclusive. METHODS: PubMed, EMBASE, ISI Web of Science, CENTRAL, and CNKI were searched to identify randomized controlled trials that compared the efficacy of Ti-PEEK and PEEK cages in lumbar fusion. Difference in fusion rate and subsidence rate was indicated by risk ratio and its associated 95% confidence interval (95% confidence interval). Mean difference was calculated for Oswestry Disability Index and visual analogue scale for low back pain. Subgroup analysis was performed by time course after the surgery. The Grading of Recommendations, Assessment, Development and Evaluation approach was used to evaluate the certainty of evidence. RESULTS: Four randomized controlled trials involving 325 patients (160 patients in Ti-PEEK group and 165 patients in PEEK group) that underwent lumbar fusion were included by our current study. Low to moderate evidence suggested that Ti-PEEK and PEEK cages exhibited equivalent fusion rate and subsidence rate at any follow-up time. Low to moderate evidence suggested that there was no difference in PROMs except for visual analogue scale measured at 6 months (mean difference: -0.57, 95% confidence interval -0.94, -0.21; P =0.002) but the difference was not clinically relevant according to the minimal clinically important difference. CONCLUSION: Low to moderate evidence showed that Ti-PEEK and PEEK had equivalent effect in bone fusion and cages subsidence at any follow-up time after lumbar fusion surgeries. Low to moderate evidence showed no clinically important difference in PROMs.

The dramatic enhancement of ferromagnetism and band gap in Fe-doped In2O3 nanodot arrays.

Ordered Fe-doped In2O3 nanodot arrays with diameters between 35 nm and 80 nm are fabricated using pulsed laser deposition with the aid of ultrathin porous anodized aluminumoxide templates. The 5 at.% Fe doped In2O3 nanodot arrays are shown to consist of the cubic bixbyite structure of In2O3. The nanodot arrays are demonstrated to be doped by Fe ions with mixed valences of +2 and +3, ruling out the presence of cluster and secondary phase related to Fe. The nanodot arrays exhibit the ferromagnetism at room temperature, where the magnetic moment increases as the dot size is reduced, rising to a maximum of about 230 emu/cm3 (equivalent to an average moment on the Fe ions of 15.30 µB/Fe). This indicates an effect due to the surface of the nanodot arrays. The optical band width is also increased to 4.55 eV for the smallest dot array, thus indicating that the surface states are responsible for the magnetism and also enhance the band gap due to Burstein-Moss effect. Our results will be benefit for understanding the physical properties of oxide semiconductor nanostructures in the application of nano-spintronics devices.

Room temperature ferromagnetism in metallic Ti1-x V x O2 thin films.

Transition metal doped TiO2 diluted magnetic semiconductors have attracted considerable interest due to their room temperature ferromagnetism. However, most TiO2 films are highly insulating, and thus the magnetic properties can not be controlled by tuning the carrier concentration. This will limit their application in controlling magnetization via electrical gating. Here, we deposit rutile Ti1-x V x O2 (x = 0.03 and 0.05) films with the thickness between 30 and 245 nm by the pulsed laser deposition technique, and observe an obvious room temperature ferromagnetic behavior in all films. The high resolution X-ray photoelectron spectroscopy results indicate that V substituting Ti4+ ions in the TiO2 lattice, with the +3 valence state having two unpaired d electrons, is responsible for the local spin. More importantly, the systemic investigations of transport properties for Ti1-x V x O2 films reveal that the films are n-type and have metallic conductivity with a carrier density of about 1020/cm3. Further studies suggest that the oxygen vacancies play a dual role of contributing to the metallic conductivity of the Ti1-x V x O2 films, and also providing the free electrons to mediate the long-range ferromagnetic coupling between two magnetic polarons. These findings may offer promise for gate-tunable ferromagnetism in future semiconductor spintronics.

Interfacial Spin Glass State and Exchange Bias in the Epitaxial La0.7Sr0.3MnO3/LaNiO3 Bilayer.

We study the magnetic properties of an epitaxial growth bilayer composed of ferromagnetic La0.7Sr0.3MnO3 (LSMO) and paramagnetic LaNiO3 (LNO) on SrTiO3 (STO) substrates. We find that the stack order of the bilayer heterostructure plays a key role in the interfacial coupling strength, and the coupling at the LSMO(top)/LNO(bottom) interface is much stronger than that at the LNO(top)/LSMO(bottom). Moreover, a strong spin glass state has been observed at the LSMO/LNO interface, which is further confirmed by two facts: first, that the dependence of the irreversible temperature on the cooling magnetic field follows the Almeida-Thouless line and, second, that the relaxation of the thermal remnant magnetization can be fitted by a stretched exponential function. Interestingly, we also find an exchange bias effect at the LSMO/LNO bilayer below the spin glass freezing temperature, indicating that the exchange bias is strongly correlated with the spin glass state at its interface.

[Determination of 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside in the traditional Chinese preparation by high performance liquid chromatography with chemiluminescence detection].

Based on the chemiluminescence reaction of KMnO4-HNO3-2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside sensitized by HCHO, an analytical method for 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside by RP-HPLC with chemiluminescence detector was developed. The chromatographic conditions were optimized. AN ODS hypersil column(25 mm x 4.0 mm, 125 x 4.0 mm i.d. 5 microm) was used with acetonitrile--0.3% H3PO4 [25:75, (phi)] as mobile phase, and the flow rate was 0.8 mL x min(-1) at the column temperature of 40 degrees C. The linear range of calibration curve was from 15.75 to 136.5 microg x mL(-1), the detection limit was 11.83 microg x mL(-1) with a concentration of 21 microg x mL(-1) of 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside, and the recovery was 102%-108%. The relative standard deviation was 3.45% (Cs = 21.0 microg x mL(-1), n = 3). The method has been applied to the determination of 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside in a few Chinese medicines, and the results were satisfactory. The method was simple, rapid and highly selective.

Morphology and magnetic properties of Fe3O 4 nanodot arrays using template-assisted epitaxial growth.

Arrays of epitaxial Fe3O4 nanodots were prepared using laser molecular beam epitaxy (LMBE), with the aid of ultrathin porous anodized aluminum templates. An Fe3O4 film was also prepared using LMBE. Atomic force microscopy and scanning electron microscopy images showed that the Fe3O4 nanodots existed over large areas of well-ordered hexagonal arrays with dot diameters (D) of 40, 70, and 140 nm; height of approximately 20 nm; and inter-dot distances (D int) of 67, 110, and 160 nm. The calculated nanodot density was as high as 0.18 Tb in.(-2) when D = 40 nm. X-ray diffraction patterns indicated that the as-grown Fe3O4 nanodots and the film had good textures of (004) orientation. Both the film and the nanodot arrays exhibited magnetic anisotropy; the anisotropy of the nanoarray weakened with decreasing dot size. The Verwey transition temperature of the film and nanodot arrays with D ≥ 70 nm was observed at around 120 K, similar to that of the Fe3O4 bulk; however, no clear transition was observed from the small nanodot array with D = 40 nm. Results showed that magnetic properties could be tailored through the morphology of nanodots. Therefore, Fe3O4 nanodot arrays may be applied in high-density magnetic storage and spintronic devices.

[Spinal balancing intervention in the treatment of tinnitus: a randomized controlled study].

OBJECTIVE: To compare the differences in the clinical efficacy on tinnitus between the spinal balancing intervention and the conventional acupuncture. METHODS: The randomized controlled trial were adopted. One hundred and twenty cases of tinnitus were randomized into a spinal balancing group and a conventional acupuncture group, 60 cases in each one. In the spinal balancing group, the comprehensive therapy of acu-puncture and Tuina was applied to the spine, the Back-shu points, Jiaji (EX-B 2), Tinggong (SI 19), Yifeng (TE 17), Fengchi (GB 20), Yuzhen (BL 9), Tianzhu (BL 10), etc. for the balancing intervention. In the conventional acupuncture group, acupuncture was applied to the local points and the points along the affected meridians. In each group, after 3 sessions of treatment, the degree of tinnitus and the accompanied symptoms were scored and compared before and after treatment. The comprehensive efficacy was assessed. RESULTS: In the spinal balancing group, the clinical curative rate was 70.0% (42/60) and the total effective rate was 98.3% (59/60), which were significantly better than 45.0% (27/60) and 86.7% (52/60) in the conventional acupuncture group separately (P < 0.01, P < 0.05). After treatment, the degree of tinnitus and the accompanied symptom scores were all reduced in both groups (all P < 0.05), but the improvements in the spinal balancing group were better than those in the conventional acupuncture group (all P < 0.05). In 3-month follow-up visit after treatment, the recurrence rate in the spinal balancing group was lower than that in the conventional acupuncture group [5.1% (3/59) vs 13.5% (7/52)] (P < 0.05). CONCLUSION: The spinal balancing intervention therapy relieves the symptoms of the patients with tinnitus remarkably. Its clinical efficacy is superior significantly to that of the conventional acupuncture and the recurrence rate is lower.