The analysis of segmental lordosis restored by oblique lumbar interbody fusion and related factors: building up preoperative predicting model.

BACKGROUND: Oblique lumbar interbody fusion (OLIF) procedures have the potential to increase the segmental lordosis by inserting lordotic cages, however, the amount of segmental lordosis (SL) changes can vary and is likely influenced by several factors, such as patient characteristics, radiographic parameters, and surgical techniques. The objective of this study was to analyze the impact of related factors on the amount of SL changes in OLIF procedures and to build up predictive model for SL changes. METHODS: This is a retrospective study involving prospectively enrolled patients. A total of 119 patients with 174 segments undergoing OLIF procedure were included and analyzed. The lordotic cages used in all cases had 6-degree angle. Radiographic parameters including preoperative and postoperative segmental disc angle (SDA, preSDA and postSDA), SDA changes on flexion-extension views (ΔSDA-FE), CageLocation and CageInclination were measured by two observers. Interobserver reliability of measurements were ensured by analysis of interclass correlation coefficient (ICC > 0.75). Pearson correlation coefficient analysis and multivariate linear regression were employed to identify factors related to SDA changes and to build up predictive model for SDA changes. RESULTS: The average change of segmental disc angle (ΔSDA, postSDA-preSDA) was 3.9° ± 4.8° (95% confidence interval [CI]: 3.1°-4.6°) with preSDA 5.3° ± 5.0°. ΔSDA was 10.8° ± 3.2° with negative preSDA (kyphotic), 5.0° ± 3.7° with preSDA ranging from 0° to 6°, and 1.0° ± 4.1° with preSDA> 6°. Correlation analysis revealed a significant negative correlation between ΔSDA and preSDA (r = - 0.713, P < 0.001), CageLocation (r = - 0.183, P = 0.016) and ΔSDA-FE (r = - 0.153, P = 0.044). In the multivariate linear regression, preSDA and CageLocation were included in the predictive model, resulting in minimal adjusted R2 change (0.017) by including CageLocation. Therefore, the recommended predictive model was ΔSDA = 7.9-0.8 × preSDA with acceptable fit. (adjusted R2 = 0.508, n = 174, P < 0.001). CONCLUSIONS: The restoration of segmental lordosis through OLIF largely depends on the preoperative segmental lordosis. The predictive model, which utilized preoperative segmental lordosis, facilitates preoperative planning for corrective surgery using the OLIF procedure.

Ventral striatal islands of Calleja neurons bidirectionally mediate depression-like behaviors in mice.

The ventral striatum is a reward center implicated in the pathophysiology of depression. It contains islands of Calleja, clusters of dopamine D3 receptor-expressing granule cells, predominantly in the olfactory tubercle (OT). These OT D3 neurons regulate self-grooming, a repetitive behavior manifested in affective disorders. Here we show that chronic restraint stress (CRS) induces robust depression-like behaviors in mice and decreases excitability of OT D3 neurons. Ablation or inhibition of these neurons leads to depression-like behaviors, whereas their activation ameliorates CRS-induced depression-like behaviors. Moreover, activation of OT D3 neurons has a rewarding effect, which diminishes when grooming is blocked. Finally, we propose a model that explains how OT D3 neurons may influence dopamine release via synaptic connections with OT spiny projection neurons (SPNs) that project to midbrain dopamine neurons. Our study reveals a crucial role of OT D3 neurons in bidirectionally mediating depression-like behaviors, suggesting a potential therapeutic target.

Comparisons of oblique lumbar interbody fusion and transforaminal lumbar interbody fusion for degenerative spondylolisthesis: a prospective cohort study with a 2-year follow-up.

Objective: This study aimed to compare the clinical outcomes between oblique (OLIF) and transforaminal lumbar interbody fusion (TLIF) for patients with degenerative spondylolisthesis during a 2-year follow-up. Methods: Patients with symptomatic degenerative spondylolisthesis who underwent OLIF (OLIF group) or TLIF (TLIF group) were prospectively enrolled in the authors' hospital and followed up for 2 years. The primary outcomes were treatment effects [changes in visual analog score (VAS) and Oswestry disability index (ODI) from baseline] at 2 years after surgery; these were compared between two groups. Patient characteristics, radiographic parameters, fusion status, and complication rates were also compared. Results: In total, 45 patients were eligible for the OLIF group and 47 patients for the TLIF group. The rates of follow-up were 89% and 87% at 2 years, respectively. The comparisons of primary outcomes demonstrated no different changes in VAS-leg (OLIF, 3.4 vs. TLIF, 2.7), VAS-back (OLIF, 2.5 vs. TLIF, 2.1), and ODI (OLIF, 26.8 vs. TLIF, 30). The fusion rates were 86.1% in the TLIF group and 92.5% in the OLIF group at 2 years (P = 0.365). The OLIF group had less estimated blood loss (median, 200 ml) than the TLIF group (median, 300 ml) (P < 0.001). Greater restoration of disc height was obtained by OLIF (mean, 4.6 mm) than the TLIF group (mean, 1.3 mm) in the early postoperative period (P < 0.001). The subsidence rate was lower in the OLIF group than that in the TLIF group (17.5% vs. 38.9%, P = 0.037). The rates of total problematic complications were not different between the two groups (OLIF, 14.6% vs. TLIF, 26.2%, P = 0.192). Conclusion: OLIF did not show better clinical outcomes than TLIF for degenerative spondylolisthesis, except for lesser blood loss, greater disc height restoration, and lower subsidence rate.

The Necessity of Implant Removal after Fixation of Thoracolumbar Burst Fractures-A Systematic Review.

BACKGROUND: Thoracolumbar burst fractures are a common traumatic vertebral fracture in the spine, and pedicle screw fixation has been widely performed as a safe and effective procedure. However, after the stabilization of the thoracolumbar burst fractures, whether or not to remove the pedicle screw implant remains controversial. This review aimed to assess the benefits and risks of pedicle screw instrument removal after fixation of thoracolumbar burst fractures. METHODS: Data sources, including PubMed, EMBASE, Cochrane Library, Web of Science, Google Scholar, and Clinical trials.gov, were comprehensively searched. All types of human studies that reported the benefits and risks of implant removal after thoracolumbar burst fractures, were selected for inclusion. Clinical outcomes after implant removal were collected for further evaluation. RESULTS: A total of 4051 papers were retrieved, of which 35 studies were eligible for inclusion in the review, including four case reports, four case series, and 27 observational studies. The possible risks of pedicle screw removal after fixation of thoracolumbar burst fractures include the progression of the kyphotic deformity and surgical complications (e.g., surgical site infection, neurovascular injury, worsening pain, revision surgery), while the potential benefits of pedicle screw removal mainly include improved segmental range of motion and alleviated pain and disability. Therefore, the potential benefits and possible risks should be weighed to support patient-specific clinical decision-making about the removal of pedicle screws after the successful fusion of thoracolumbar burst fractures. CONCLUSIONS: There was conflicting evidence regarding the benefits and harms of implant removal after successful fixation of thoracolumbar burst fractures, and the current literature does not support the general recommendation for removal of the pedicle screw instruments, which may expose the patients to unnecessary complications and costs. Both surgeons and patients should be aware of the indications and have appropriate expectations of the benefits and risks of implant removal. The decision to remove the implant or not should be made individually and cautiously by the surgeon in consultation with the patient. Further studies are warranted to clarify this issue. LEVEL OF EVIDENCE: level 1.

Increased Carotid Siphon Tortuosity Is a Risk Factor for Paraclinoid Aneurysms.

Background: Geometrical factors associated with the surrounding vasculature can affect the risk of aneurysm formation. The aim of this study was to determine the association between carotid siphon curvature and the formation and development of paraclinoid aneurysms of the internal carotid artery. Methods: Digital subtraction angiography (DSA) data from 42 patients with paraclinoid aneurysms (31 with non-aneurysmal contralateral sides) and 42 age- and gender-matched healthy controls were analyzed, retrospectively. Morphological characteristics of the carotid siphon [the posterior angle (α), anterior angle (ß), and Clinoid@Ophthalmic angle (γ)] were explored via three-dimensional rotational angiography (3D RA) multiplanar reconstruction. The association between carotid siphon morphology and the formation of paraclinoid aneurysms was assessed through univariate analysis. After this, logistic regression analysis was performed to identify independent risk factors for aneurysms. Results: Significantly smaller α, ß, and γ angles were reported in the aneurysmal carotid siphon group when compared with the non-aneurysmal contralateral healthy controls. The ß angle was best for discriminating between aneurysmal and non-aneurysmal carotid siphons, with an optimal threshold of 18.25°. By adjusting for hypertension, smoking habit, hyperlipidemia, and diabetes mellitus, logistic regression analysis demonstrated an independent association between the carotid siphons angles α [odds ratio (OR) 0.953; P < 0.05], ß (OR 0.690; P < 0.001), and γ (OR 0.958; P < 0.01) with the risk of paraclinoid aneurysms. Conclusions: The present findings provide evidence for the importance of morphological carotid siphon variations and the likelihood of paraclinoid aneurysms. These practical morphological parameters specific to paraclinoid aneurysms are easy to assess and may aid in risk assessment in these patients.

Additional lateral plate fixation has no effect to prevent cage subsidence in oblique lumbar interbody fusion.

BACKGROUND: For lumbar degenerative diseases, cage subsidence is a serious complication and can result in the failure of indirect decompression in the oblique lumbar interbody fusion (OLIF) procedure. Whether additional lateral plate fixation was effective to improve clinical outcomes and prevent cage subsidence was still unknown. This study aimed to compare the incidence and degree of cage subsidence between stand-alone oblique lumbar interbody fusion (SA-OLIF) and OLIF combined with lateral plate fixation (OLIF + LP) for the treatment of lumbar degenerative diseases and to evaluate the effect of the lateral plate fixation. METHODS: This was a retrospective comparative study. 20 patients with 21 levels underwent SA-OLIF and 21 patients with 26 levels underwent OLIF + LP. We compared clinical and radiographic outcomes between two groups. Clinical evaluation included Visual Analog Scale (VAS) for back pain and leg pain, Japanese Orthopaedic Association (JOA) scores and Oswestry Disability Index (ODI). Radiographical evaluation included disc height (DH), segmental lordosis angle (SL), and subsidence rate on standing lateral radiographs. Cage subsidence was classified using Marchi's criteria. RESULTS: The mean follow-up duration was 6.3 ± 2.4 months. There were no significant differences among perioperative data (operation time, estimated intraoperative blood loss, and complication), clinical outcome (VAS, ODI, and JOA) and radiological outcome (SH and SL). The subsidence rate was 19.0% (4/21) in SA-OLIF group and 19.2% (5/26) in OLIF + LP group. 81.0% in SA-OLIF group and 80.8% in OLIF + LP group had Grade 0 subsidence, 14.3% in SA-OLIF group and 15.4% in OLIF + LP group had Grade I subsidence, and 4.8% in SA-OLIF group and 3.8% in OLIF + LP group had Grade II subsidence (P = 0.984). One patient with severe cage subsidence and lateral plate migration underwent revision surgery. CONCLUSIONS: The additional lateral plate fixation does not appear to be more effective to prevent cage subsidence in the oblique lumbar interbody fusion, compared with stand-alone technique. If severe cage subsidence occurs, it may result in lateral plate migration in OLIF combined with lateral plate fixation.

An Integrated Positioning and Attitude Determination System for Immersed Tunnel Elements: A Simulation Study.

Immersed tunnel elements need to be exactly controlled during their immersion process. Position and attitude of the element should be determined quickly and accurately to navigate the element from the holding area to the final location in the tunnel trench. In this paper, a newly-developed positioning and attitude determination system, integrating a 3-antenna Global Navigation Satellite System (GNSS) system, an inclinometer and a range-measurement system, is presented. The system is designed to provide the absolute position of both ends of the element with sufficient accuracy in real time. Special attention in the accuracy analysis is paid to the influence of GNSS multipath error and sound speed profile. Simulations are conducted to illustrate the performance of the system in different scenarios. If both elements are very close, the accuracies of the system are higher than 0.02 m in the directions perpendicular to and along the tunnel axis.

The mechanism for bacteriophage f2 removal by nanoscale zero-valent iron.

Nanoscale zero-valent iron (NZVI) has shown excellent performance for pathogenic microorganism removal but the inactivation mechanism has not been understood clearly enough. In this study, the bacteriophage f2 removal by NZVI under aerobic and anaerobic conditions was investigated, and various factors involved in f2 removal were analyzed in detail, including the ion products of NZVI (Fe(II), Fe(III)), solid phase products, the reactive oxygen species (ROS), O2 and H+. In addition, the morphologies of bacteriophage f2 during reaction were observed. The results showed that the removal efficiency of bacteriophage f2 was much higher under aerobic conditions than that in anaerobic systems, and oxygen and pH were determinants for f2 removal. The oxidation of Fe(II) was a fundamental step and played a significant role in bacteriophage f2 removal, especially in the aerobic systems. In the presence of oxygen, the virus removal was attributed to the generation of ROS (namely ·OH and ·O2-) and the oxidized iron, in which the ROS (·OH and ·O2-) made a predominant contribution. And the adsorption of iron oxide was responsible for the removal in oxygen depleted circumstance. In the anaerobic system, the virus removal was mainly attributed to the interaction between NZVI and bacteriophage f2. Besides, from the perspective of TEM images, the virus removal was mainly attributed to the damage of infective ability by NZVI at the initial stage of reaction, and later the virus was inactivated by the ROS generated.

Removing pentachlorophenol from water using a nanoscale zero-valent iron/H2O2 system.

Nanoscale zero-valent iron (nZVI) is an environmentally benign material that has been widely used as a reducing agent to treat environmental pollutants. In this study, nZVI was used as a heterogeneous Fenton catalyst in an nZVI/H2O2 system to remove pentachlorophenol (PCP) from water. The PCP degradation process in the nZVI/H2O2 system was completed within 1h. The relative Cl(-) concentration increased throughout the test period (6h), indicating that the performance of the oxidative system in terms of dechlorination was excellent. The initial H2O2 concentration significantly influenced the PCP removal rate, and nZVI performed better than commercial zero-valent iron as a catalyst. Moreover, magnetite (Fe3O4), which was the main product of the corrosion of nZVI, was found to perform well as an adsorbent and catalyst, so it allowed the nZVI to be effectively reused.