Search

There are many models of lumbar disc degeneration, but mechanical stress-induced lumbar disc degeneration is rare. Here we propose a mechanical stress-induced lumbar disc degeneration model to better understand the molecular mechanism of lumbar disc degeneration under stress stimulation. To design a new model of lumbar disc degeneration under mechanical stress. The anatomic approach of the oblique lateral approach to lumbar fusion surgery was used to design a longitudinal compression device across the vertebral body of the rabbit to impose longitudinal load on the lumbar disc. New Zealand white rabbits (n=30) were used. Screws were used to cross the rabbits' lumbar vertebral bodies, and both sides of the screws were pressurized. Continuous compression was then performed for 28 days. Adjacent unpressurized lumbar discs serve as controls for pressurized lumbar discs. At 28 days after surgery, micro-computed tomography (CT) and magnetic resonance imaging (MRI) were performed on the rabbits' lumbar discs. After the imaging examination, lumbar disc samples were removed, Safranin-O fast green and immunofluorescence was performed to detect the expression level of intervertebral disc degeneration-related proteins. The CT results showed that the disc height did not decrease significantly after mechanical loading. The MRI results showed that the signals in the pressurized disc decreased 28 days after loading. The results of Safranin-O fast green showed that the cartilage component of the intervertebral disc after mechanical compression was significantly reduced. The immunofluorescence results showed that the expression of ADAMTS5 and MMP13 protein in the nucleus pulposus of the intervertebral disc after mechanical compression increased, while the expression of SOX9 decreased, and the difference was statistically significant. Aggrecan's protein expression decreased, but was not statistically significant. This study designed a reliable model of disc degeneration in rabbits. It is more likely to mimic disc compression in the human body. This animal model can be used as a basic model to study the molecular physiological mechanisms of discogenic low back pain. [ABSTRACT FROM AUTHOR]

Reoperation, sometimes multiple, is common with progressively worse outcomes in patients with degenerative lumbar spine diseases. Lysophosphatidylcholine (LPC), a precursor of lysophosphatidic acid, in the cerebrospinal fluid (CSF) is a possible biomarker for neuropathic pain and discriminating neuropathic pain caused by lumbar spinal canal stenosis (LSCS) from other etiologies. This study aimed to explore this possible use of LPC species in the CSF. Patients with LSCS (n = 137) and persistent spinal pain syndrome (n = 22) were subjected in this multi-site observational study. The CSF was collected by lumbar puncture. Using liquid chromatography-tandem mass spectrometry, we measured 6 LPC species, (16:0), (18:0), (18:1), (18:2), (20:4), and (22:6), in the CSF. We compared the LPC values between the groups and determined the cutoff levels that could efficiently discriminate the groups with high accuracy. The levels of all measured LPC species were significantly higher in the LSCS group than the persistent spinal pain syndrome group. Four LPC species demonstrated more than 0.80 area under the curve obtained from the receiver operating characteristic curve analysis. Although the specificity of cutoff levels for the 6 LPC species was low to moderate, their sensitivity was consistently high. The existing diagnostic protocols combining physical examinations and morphological imaging studies for lumbar spinal pain have limited sensitivity. Measuring LPC species in the CSF is a promising objective laboratory test and could be suitable for detecting the presence of lumbar spinal stenosis and can help indications for surgery. [ABSTRACT FROM AUTHOR]

Spinal fusion is the mainstay treatment for various spinal conditions ranging from lumbar and cervical stenosis to degenerative spondylolisthesis as well as extensive deformity corrections. A new emerging category of allograft is cellular bone matrices (CBMs), which take allogeneic mesenchymal stem cells and incorporate them into an osteoconductive and osteoinductive matrix. This study reviewed the current spinal fusion options and new emerging treatment options. Articles were searched using PubMed. The search included English publications since January 1, 2014, using the search terms "cellular bone matrix," "mesenchymal stem cells spinal fusion," "spinal arthrodesis AND mesenchymal stem cells," and "spine fusion AND cellular bone matrix." Spinal fusion is accomplished through the use of allografts, autografts, and bone graft substitutes in combination or alone. An emerging category of allograft is CBMs, in which an osteoconductive and osteoinductive matrix is filled with mesenchymal stem cells. Studies demonstrate that CBMs have achieved equivalent or better fusion rates compared with traditional options for anterior cervical discectomy and fusions and posterolateral lumbar fusions; however, the studies have been retrospective and lacking control groups and therefore not ideal. Many treatment options have been successfully used in spinal fusion. Newer allografts such as CBMs have shown promising results in both animal and clinical studies. Further research is needed to determine the therapeutic dose of mesenchymal stem cells delivered within CBMs. [ABSTRACT FROM AUTHOR]

Background: Distal tibialis anterior tendinopathy (DTAT) is condition which is infrequently described in literature and is usually treated with conservative means. If resistant to a rehabilitation protocol and unloading, a surgical treatment could be proposed. The aim of this research is to report on the history and clinical image of DTAT and present the clinical results of a simple surgical decompression of the tendon with local debridement and release of the distal extensor retinaculum.Methods: Seventeen patients diagnosed with DTAT in 18 feet underwent surgery between 2008 and 2018. Upon initial presentation, all patients reported a persistent history of pain over the tibialis anterior (TA) insertion. Ultrasound was routinely performed to confirm the diagnosis. In patients with confirmed diagnosis of DTAT, persistent despite conservative treatment, we proceeded with surgical intervention during which we released the tendon by opening the distal extensor retinaculum. Retrospective chart review was performed, and functional outcomes were assessed using the AOFAS midfoot score. AOFAS score results were collected postoperatively with at least one-year follow-up.Results: All patients experienced pain on palpation of the distal aspect of the TA tendon. Most patients experienced pain at night and were frequent hikers. Our study population consisted of mostly female and overweight patients. All patients reported pain relief with a significant improvement of VAS for pain from 6.7 ± 1.1 preoperatively to 1.1 ± 1.2 postoperatively (p < 0.05). The postoperative AOFAS midfoot score was 97 ± 3.7. Fifteen patients were completely satisfied, two satisfied with minor reservations.Conclusion: Simple distal TA tendon release by division of a consistently present constricting distal extensor retinaculum represents a surgical alternative in the treatment of chronic DTAT. Our study shows good clinical outcomes with low complications.Level Of Evidence: Level IV - retrospective case series. [ABSTRACT FROM AUTHOR]

Aim Of the Study: Controlled sequential elevation of the head and thorax (CSE) during active compression decompression (ACD) cardiopulmonary resuscitation (CPR) with an impedance threshold device (ITD) has been shown to increase cerebral perfusion pressure and cerebral blood flow in previous animal studies as compared to the traditional supine position. The potential for this novel bundled treatment strategy to improve survival with intact neurological function is unknown.Methods: Female farm pigs were sedated, intubated, and anesthetized. Central arterial and venous access were continuously monitored. Regional brain tissue perfusion (CerO2) was also measured transcutaneous. Ventricular fibrillation (VF) was induced and untreated for 10 min. Pigs were randomized to (1) Conventional CPR (C-CPR) flat or (2) ACD + ITD CSE CPR that included 2 min of ACD + ITD with the head and heart first elevated 10 and 8 cm, and then gradual elevation over 2 min to 22 and 9 cm, respectively. After 19 min of CPR, pigs were defibrillated and recovered. A veterinarian blinded to the intervention assessed cerebral performance category (CPC) at 24 h. A neurologically intact outcome was defined as a CPC score of 1 or 2. Categorical outcomes were analyzed by Fisher's exact test and continuous outcomes with an unpaired student's t-test.Results: In 16 animals, return of spontaneous circulation rate was 8/8 (100%) with ACD + ITD CSE and 3/8 (25%) for C-CPR (p = 0.026). For the primary outcome of neurologically intact survival, 6/8 (75%) pigs had a CPC score 1 or 2 with ACD + ITD CSE versus 1/8 (12.5%) with C-CPR (p = 0.04). Coronary perfusion pressure (mmHg, mean ± SD) was higher with CSE at 18 min (41 ± 24 versus 10 ± 5, p = 0.004). rSO2 (%, mean ± SD) and ETCO2 (mmHg, mean ± SD) values were higher at 18 min with CSE (32 ± 9 versus 17 ± 2, p = 0.01, and 55 mmHg ± 10 versus 21 mmHg ± 4, p < 0.001), respectively.Conclusions: The novel bundled resuscitation approach of CSE with ACD + ITD CPR increased favorable neurological survival versus C-CPR in a swine model of cardiac arrest. [ABSTRACT FROM AUTHOR]

We aimed to compare the clinical and radiological outcomes of midline lumbar fusion (MIDLF) versus minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) in patients with degenerative spondylolisthesis and/or stenosis in L4-L5 two years after surgery. Consecutively treated patients with lumbar pathology who underwent MIDLF (n = 16) and a historical control group who underwent MI-TLIF (n = 34) were included. Clinical symptoms were evaluated using Oswestry Disability Index (ODI), the 36-Item Short-Form Health Survey, and visual analog scale (VAS) scores before surgery and 3, 6, 12, and 24 months after surgery. The mean operative time and hematocrit (HCT, Day 1) were significantly shorter and lower in MIDLF cases (174 min vs. 229 min, P < 0.001; 0.34 vs. 0.36, P = 0.037). The MI-TLIF group showed better improvement than the MIDLF group in ODI and VAS back and leg pain at 3 months postoperatively. VAS leg pain was higher in MIDLF than in MI-TLIF cases at 6 months. At 24 months follow-up, VAS back pain was higher in MI-TLIF than in MIDLF cases (P = 0.018). MIDLF is comparable to MI-TLIF at L4-5 in clinical outcomes and fusion rates, and the results verified the meaningful advantage of using MIDLF for the elderly with osteoporosis. [ABSTRACT FROM AUTHOR]

• Vascular smooth muscle cells are decompressed from hyperbaric exposure. • Mitochondrial motility and respiratory function are affected. • A succinate prodrug provides partial prophylaxis from these effects. Mitochondrial dysfunction occurring in response to cellular perturbations can include altered mitochondrial motility and bioenergetic function having intracellular heterogeneity. Exogenous mitochondrial directed therapy may correct these dysfunctions. Using in vitro approaches, we find that cell perturbations induced by rapid decompression from hyperbaric conditions with specific gas exposures has differential effects on mitochondrial motility, inner membrane potential, cellular respiration, reactive oxygen species production, impaired maintenance of cell shape and altered intracellular distribution of bioenergetic capacity in perinuclear and cell peripheral domains. Addition of a first-generation cell-permeable succinate prodrug to support mitochondrial function has positive overall effects in blunting the resultant bioenergy responses. Our results with this model of perturbed cell function induced by rapid decompression indicate that alterations in bioenergetic state are partitioned within the cell, as directly assessed by a combination of mitochondrial respiration and dynamics measurements. Reductions in the observed level of dysfunction produced can be achieved with application of the cell-permeable succinate prodrug. [ABSTRACT FROM AUTHOR]

A 3-year-old male with no past medical history presented with flaccid plegia of his upper extremities and significant weakness in his lower extremities after wrestling with his brother. Cervical spine magnetic resonance imaging was consistent with cord edema and intraparenchymal hemorrhage at C1-C2. A nonossified tissue mass at the expected location of the upper dens created narrowing of the canal at the C1-2 level and mass effect on the cord. Head computed tomography showed periventricular leukomalacia. Initial findings favored dysplasia of the odontoid with associated soft tissue mass/pannus caused by a possible underlying genetic or metabolic bone dyscrasia. The patient underwent suboccipital craniotomy/C1 laminectomy and occiput to C4 fusion, for decompression and stabilization. Genetic testing showed a COL2A1 collagen disorder, with the child harboring a de novo mutation for c.3455 G>T (p.G1152V). The patient was discharged to inpatient acute rehabilitation, with gradual improvement in strength in all 4 extremities. [ABSTRACT FROM AUTHOR]

Purpose: It has previously been shown that continuous intratracheal insufflation of oxygen (CIO) is superior to intermittent positive pressure ventilation (IPPV) regarding gas exchange and haemodynamics. The purpose of this study was to investigate gas exchange and haemodynamics with a new technique of phase-controlled intermittent insufflation of oxygen (PIIO) compared to CIO.Method: Twenty (20) pigs were used, stratified into two groups (CIO, PIIO), with 10 animals each. Upon induction of ventricular fibrillation, standard ventilator support was replaced by either of CIO or PIIO ventilation. Chest compressions were delivered by the LUCAS I mCPR device. Following 20 min of CPR in normothermia, defibrillation was attempted.Results: Return of spontaneous circulation (ROSC) occurrence was not significantly higher (P < 0.16) in the PIIO (9/10) than in the CIO (6/10) group. During the decompression phase the PIIO group showed significant increases in mean (P < 0.01), maximal (P < 0.02) and end-decompression (P < 0.01) coronary perfusion pressure (CPP), compared to the CIO group. PIIO resulted in increased compression phase aortic pressure (P < 0.03). Intratracheal pressure was 5-30 cmH2O within both groups during mCPR, with a significantly lower (P < 0.02) mean for the PIIO group. Arterial and venous blood gas analysis showed comparable results between the groups, when taking base line values into account. An exception was that PIIO resulted in significantly higher (P < 0.05) oxygen partial pressure during mCPR, and lower (P < 0.05) arterial lactate following ROSC.Conclusion: PIIO results in significantly higher CPP and compression phase aortic pressure during mCPR in a porcine population. Further studies are needed to validate these findings in humans. Study protocol conforming with ethic approval M174-15, issued by the Malmö/Lunds regionala djurförsöksetiska nämnd (REB). [ABSTRACT FROM AUTHOR]

Objective Postoperative C5 palsy is a well-known complication after cervical decompression with either a posterior or an anterior approach. Its cause has been discussed more regarding the posterior approach. The main hypothesis is that postoperative spinal cord shift causes root traction and palsy. However, the pathogenesis in anterior cases has not been fully described. Therefore, the purpose of this study was to clarify the risk factors for C5 palsy in the anterior approach through our C5 palsy cases. Methods A total of 149 surgical patients with an anterior cervical lesion were treated by a specific spinal surgeon under consistent same treatment strategy. Of these patients, 88 who satisfied the evaluation criteria were enrolled. Postoperative C5 palsy was defined as postoperative weakness of the deltoid with or without weakness of the biceps brachii. Risk factors of C5 palsy were extracted from clinical backgrounds, surgical approaches, and radiologic findings from patients with palsy. Results Four sides of 3 individuals (4.6%) who underwent multiple corpectomy developed C5 palsy. All paralyses became evident several days after the surgery and recovered. Older age, multiple corpectomy, postoperative spinal cord shift, and foraminal stenosis of C4-5 and C5-6 were statistically extracted as causative factor of C5 palsy. In the patients with palsy, distortion of the anterior nerve root as a result of a residual vertebral spur was observed with anterior spinal cord shift after anterior corpectomy. Conclusions Multiple corpectomy for patients with longer anterior lesions and locally developed kyphosis is related to a larger postoperative cord shift, which can cause the occurrence of C5 palsy. Moreover, C4-5 or C5-6 foraminal stenosis can accelerate tethering of the C5 or C6 nerve root. Older patients undergoing multiple corpectomy are susceptible to these risks of palsy. Appropriate patient selection and sufficient additional foraminotomy should be considered for extensive anterior lesions and locally developed kyphosis to avoid postoperative C5 palsy. Highlights • Spinal cord shift is associated with the occurrence of C5-palsy after ACDF/ACCF. • C4-5 or C5-6 foraminal stenosis can accelerate tethering of the C5 or C6 nerve root. • Patient selection and sufficient foraminotomy may help to avoid C5-palsy in extensive ACCF. [ABSTRACT FROM AUTHOR]

High pressure (HP) processing has high potential for bacterial spore inactivation with minimal thermal input. To advance HP germination and subsequent inactivation of spores, this study explored the physiological state of HP-treated spores using flow cytometry (FCM). Bacillus subtilis spores were treated at 550 MPa and 60 °C (very HP (vHP)) in buffer, incubated after the HP treatment, and stained for FCM analysis with SYTO16 indicating germination and propidium iodide (PI) indicating membrane damage. FCM subpopulations were analyzed depending on the HP dwell time (≤20 min), post-HP temperature (ice, 37 °C, 60 °C) and time (≤4 h), germination-relevant cortex-lytic enzymes (CLEs) and small-acid-soluble-proteins-(SASP)-degrading enzymes by using deletion strains. The effect of post-HP temperatures (ice, 37 °C) was additionally studied for moderate HP (150 MPa, 38 °C, 10 min). Post-HP incubation conditions strongly influenced the prevalence of five observed FCM subpopulations. Post-HP incubation on ice did not or only slowly shifted SYTO16-positive spores to higher SYTO16 levels. At 37 °C post-HP, this shift accelerated, and a shift to high PI intensities occurred depending on the HP dwell time. At 60 °C post-HP, the main shift was from SYTO16-positive to PI-positive subpopulations. The enzymes CwlJ and SleB, which are CLEs, seemed both necessary for PI or SYTO16 uptake, and to have different sensitivities to 550 MPa and 60 °C. Different extents of SASP degradation might explain the existence of two SYTO16-positive subpopulations. Shifts to higher SYTO16 intensities during post-HP incubation on ice or at 37 °C might rely on the activity and recovery of CLEs, SASP-degrading enzymes or their associated proteins from reversible HP-induced structural changes. These enzymes seemingly become active only during decompression or after vHP treatments (550 MPa, 60 °C). Based on our results, we provide a refined model of HP germination-inactivation of B. subtilis spores and an optimized FCM method for quantification of the safety-relevant subpopulation, i.e., vHP (550 MPa, 60 °C) superdormant spores. This study contributes to the development of mild spore inactivation processes by shedding light on overlooked parameters: post-HP incubation conditions. Post-HP conditions significantly influenced the physiological state of spores, likely due to varying enzymatic activity. This finding may explain inconsistencies in previous research and shows the importance of reporting post-HP conditions in future research. Furthermore, the addition of post-HP conditions as HP process parameter may open up new possibilities to optimize HP-based inactivation of spores for potential industrial applications in the food industry. • The temperature and time after high pressure (HP) treatment strongly affected the physiological state of spores. • The changes in the physiological state were reflected in propidium iodide and SYTO16 staining. • Germination enzyme activity depended not only on HP but also on post-HP conditions — previously overlooked parameters. • New insights in the temporal sequence of HP germination or inactivation steps were gained. [ABSTRACT FROM AUTHOR]

Dielectric elastomer actuator augmented aorta (DEA) represents a novel approach with high potential for assisting a failing heart. The soft tubular device replaces a section of the aorta and increases its diameter when activated. The hemodynamic interaction between the DEA and the left ventricle (LV) has not been investigated with wave intensity (WI) analysis before. The objective of this study is to investigate the hemodynamic effects of the DEA on the aortic WI pattern. WI was calculated from aortic pressure and flow measured in-vivo in the descending aorta of two pigs implanted with DEAs. The DEAs were tested for different actuation phase shifts (PS). The DEA generated two decompression waves (traveling upstream and downstream of the device) at activation followed by two compression waves at deactivation. Depending on the PS, the end-diastolic pressure (EDP) decreased by 7% (or increased by 5–6%). The average early diastolic pressure augmentation ( P dia ¯ ) increased by 2% (or decreased by 2–3%). The hydraulic work (W H) measured in the aorta decreased by 2% (or increased by 5%). The DEA-generated waves interfered with the LV-generated waves, and the timing of the waves affected the hemodynamic effect of the device. For the best actuation timing the upstream decompression wave arrived just before aortic valve opening and the upstream compression wave arrived just before aortic valve closure leading to a decreased EDP, an increased P dia ¯ and a reduced. W H. [ABSTRACT FROM AUTHOR]

Background Bow hunter's syndrome is a symptomatic vertebrobasilar insufficiency resulting from a rotational stenosis or occlusion of a dominant vertebral artery (VA). The VA is dynamically compressed by cervical osteoarthritis (discovertebral structure or osteophytes) during head rotation or neck extension. Diagnosis is based on dynamic computed tomography angiography and confirmed with dynamic catheter angiography. Surgery tends to be the best treatment option in most cases. Dynamic intraoperative assessment of VA decompression seems to improve surgical results but remains poorly evaluated in the literature. Case Description A 70-year-old man with bow hunter's syndrome related to left VA compression by C3-4 osteophyte protrusion presented with syncopal episodes during left head rotation. Bow hunter's syndrome was successfully managed with an anterior transuncal surgical decompression of the left VA and C3-4 fusion. Surgical decompression was guided by dynamic intraoperative catheter angiography and secured with an intra-arterial remodeling balloon placed just before surgery. The patient was symptom-free after surgery. Conclusions Surgical decompression guided by dynamic intraoperative catheter angiography leads to selective VA release and allows real-time assessment of the efficacy of the decompression. This multidisciplinary treatment involving neurosurgical and neuroradiologic teams is a simple and effective treatment. Dynamic intraoperative catheter angiography is an essential guide to perform selective decompression of the VA, and implementation of an intra-arterial remodeling balloon can improve the safety of surgery making this method valuable compared with other intraoperative assessment techniques, such as Doppler ultrasound and indocyanine green fluorescent videography. Highlights • BHS is a rare syndrome related to rotational compression of VA during head rotation. • Typical manifestations are vertigo or syncope spontaneously reversible after head reposition. • Surgery is indicated in most cases with good outcomes. • DIOA leads to selective VA release and allows real-time assessment of efficacy of decompression. • Implementation of an intra-arterial remodeling balloon can improve the safety of surgery. [ABSTRACT FROM AUTHOR]

Bubbles forming due to decompression of a liquid saturated with dissolved gas at elevated pressures when it enters a low pressure liquid pool can either limit or promote the efficiency of several ground and space applications. Among the experimental parameters influencing flow decompression degassing, dissolution pressure is the most studied, yet controversial, parameter. The present work aims to shed light on how dissolution pressure of a liquid affects the final size of bubbles and the generated gas fraction by conducting gas desorption (degassing) experiments of liquid jets that decompress passing though a nozzle to a vertical column filled with the same non-degassed liquid. Bubbles size distributions at different radial positions in the column are computed analyzing high resolution digital images. A patented electrical impedance technique is employed to measure instantaneously local volumetric gas fraction. Flow dispersion in the column is studied by residence time distributions using conductivity tracers. On-line continuous dissolved oxygen measurements yield the kinetics and final extent of degassing. Experimental results are discussed to comprehend why bubbles size distributions vary with dissolution pressures and how this variation affects gas fraction in the column. [ABSTRACT FROM AUTHOR]

Background: Cost-utility analysis of surgery for degenerative lumber spondylolisthesis (DS) is essential for healthcare providers and patients to select appropriate treatment. The purpose of this study was to review the cost-utility of decompression alone versus decompression with fusion for DS.Methods: A retrospective review of 99 consecutive patients who were treated for Meyerding grade 1 DS at two representative spine centers was performed. Patients with significant spinal instability were treated by decompression with fusion (F group, 40 patients); all others were treated by decompression surgery alone (D group, 59 patients). All patients were followed for three years. Demographic and radiographic data, health-related quality of life (HRQoL), and the direct cost for surgery were analyzed, and the incremental cost-effectiveness ratio (ICER) was determined using cost/quality-adjusted life years (QALY).Results: There were no differences between the groups in baseline demographics (D vs. F: age 68 ± 9 vs. 66 ± 7 years; 37% vs. 40% female) or HRQoL (ODI: D, 41 ± 16 vs. F, 46 ± 13%). The F group had a higher initial-surgery cost ($18,992 ± 2932) but lower reoperation frequency (7%) than the D group ($7660 ± 2182 and 12%, respectively). The three-year total direct cost was higher for F than for D ($19,222 ± 3332 vs. $9668 ± 6,168, p = .01). ICER was higher for F at one year ($136,408 ± 187,911 vs. $237,844 ± 212,049, p < .01), but was comparable for F and D at three years (D, $41,923 ± 44,503 vs. F, $51,313 ± 32,849, p = .17).Conclusion: At the three-year follow-up, the two methods had comparable cost-utility. Both methods were cost-effective (defined as an ICER within three times the per-capita gross domestic product). [ABSTRACT FROM AUTHOR]

Objective To examine a new abnormal muscle response (AMR) monitoring method during microvascular decompression (MVD) for hemifacial spasm. Methods 486 patients with hemifacial spasm were monitored for an AMR during MVD with a new method involving preoperative mapping and intraoperative centrifugal stimulation of the facial nerve. For the last 62 patients, we performed the AMR monitoring using both, the new and conventional methods simultaneously. Results Preoperative facial nerve mapping showed that the maximal AMR was detected most frequently (66.9%) at the “F” location (the direction towards the frontalis muscle). An intraoperative AMR was observed in 86.2% of the patients, which disappeared after MVD in 96.4% of the patients. A comparison of the new and conventional methods respectively showed that AMR disappearance after MVD was observed in 98.2% and 61.8% of the patients, no AMR in 0% and 9.1%, and persistent AMR after MVD in 1.8% and 29.1%. Conclusions The new AMR monitoring method demonstrated greater AMR monitoring efficacy and supports the finding that disappearance of an AMR is a good indicator of effective decompression during MVD surgery. Significance Preoperative mapping and intraoperative centrifugal stimulation of the facial nerve during MVD surgery in HFS patients showed greater efficacy of AMR monitoring. [ABSTRACT FROM AUTHOR]

Objective The aim of this study was to define the critical warning sign of real-time brainstem auditory evoked potential (BAEP) for predicting hearing loss (HL) after microvascular decompression (MVD) for hemifacial spasm (HFS). Methods Nine hundred and thirty-two patients with HFS who underwent MVD with intraoperative monitoring (IOM) of BAEP were analyzed. We used a 43.9 Hz/s stimulation rate and 400 averaging trials to obtain BAEP. To evaluate HL, pure-tone audiometry and speech discrimination scoring were performed before and one week after surgery. We analyzed the incidence for postoperative HL according to BAEP changes and calculated the diagnostic accuracy of significant warning criteria. Results Only 11 (1.2%) patients experienced postoperative HL. The group showing permanent loss of wave V showed the largest percentage of postoperative HL ( p  < 0.001). No patient who experienced only latency prolongation (≥1 ms) had postoperative HL. Loss of wave V and latency prolongation (≥1 ms) with amplitude decrement (≥50%) were highly associated with postoperative HL. Conclusions Loss of wave V and latency prolongation of 1 ms with amplitude decrement ≥50% were the critical warning signs of BAEP for predicting postoperative HL. Significance These findings elucidate the critical warning sign of real-time BAEP. [ABSTRACT FROM AUTHOR]

Using PS colloidal spheres as the template, 3DOM Ag/CeO 2 -ZrO 2 was synthesized by the sol–gel combined with the decompression filling method, which showed a good crystal structure with an orderly, open, transparent macroporous structure, and with a large specific surface area. The synergy of SPR effect and Z-scheme of Ag on 3DOM Ag/CeO 2 -ZrO 2 can evidently enhance the photocatalytic degradation and water splitting performance. [Display omitted] • Using PS colloidal spheres as the template, 3DOM Ag/CeO 2 -ZrO 2 was synthesized by the sol–gel combined with the decompression filling method. • 3DOM Ag/CeO2-ZrO2 showed a good crystal structure with an especial structure, and with a large specific surface area. • The synergy of SPR effect and Z-scheme of Ag on 3DOM Ag/CeO2-ZrO2 evidently enhanced the photocatalytic performance. • 3DOM Ag/CeO 2 -ZrO 2 showed preferably activities during multimode photocatalytic degradation and water splitting into hydrogen experiments. Using polystyrene spheres (PS) as a template, a kind of three-dimensionally ordered macroporous (3DOM) Ag/CeO 2 -ZrO 2 material was synthesized by the sol–gel combined with the decompression filling method. A series of characterization methods, such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (UV–vis/DRS), Scanning electron microscopy (SEM), High-resolution transmission electron microscopy (HR-TEM), and N 2 adsorption–desorption measurements were used to study its composition, structure, morphology, and surface physicochemical properties. The synthesized composite material 3DOM Ag/CeO 2 -ZrO 2 shows a good crystal structure, open and transparent arrangement in a three-dimensional space. Meanwhile, compared with the sample without PS treatment, the composite material has a smaller band gap energy value, which means under the excitation of light, it is easier to produce electron–hole pairs and enables to absorb more reactive molecules on the surface of the catalyst, thus improving the photocatalytic performance of the composite. And after loading Ag metal on the composite, the light absorption of the catalyst is extended to the visible region by the surface plasmon resonance effect (SPR), resulting in promoting the absorption efficiency of light. During multimode photocatalytic degradation experiments of Congo Red (CR), 3DOM Ag/CeO 2 -ZrO 2 composite exhibited an excellent photocatalytic performance. Under ultraviolet light, its catalytic performance was much better than that of both commercial catalyst P25 and the sample without loading Ag. At the same time, in the photocatalytic hydrogen evolution experiment, 3DOM Ag/CeO 2 -ZrO 2 showed a stronger ability of water splitting into hydrogen, whose hydrogen yield (53 μmol in 8 h) was about 4 times than that of P25, indicating 3DOM Ag/CeO 2 -ZrO 2 had the ability of photodegradation and photolysis of water. In addition, superoxide free radical (O 2 −), hydroxyl radical (OH), and hole (h+) were considered as main reactive groups in the photocatalytic process according to capture experimental results. Moreover, the transfer effect of Ag as Z-Scheme in the photocatalytic reaction was speculated as well. [ABSTRACT FROM AUTHOR]

Wilkie's syndrome or superior mesenteric artery (SMA) syndrome is a rare etiology of duodenal obstruction due to compression of the third portion of the duodenum between the superior mesenteric artery and the aorta. The aorta–SMA angle ranges from 38° to 65° and the distance between the two is 10-28 mm. The main anatomical feature of SMA syndrome is the narrowing of the aorta–SMA angle to < 25° and a decrease in the aortomesenteric distance < 10 mm, causing the specific duodenal obstruction symptoms. A 17-year-old female presented in our outpatient clinic with persistent epigastric pain, early satiety, pyrosis, and weight loss (cca. 8 kg) in the last year, that had worsened at the time of presentation. An abdominal ultrasound (US) was performed after 14 hours of fasting. It revealed gastric dilatation suggesting upper gastrointestinal outlet obstruction. We admitted the patient to our hospital where we performed gastric decompression via a nasogastric tube. Blood work was unremarkable. The abdominal computer tomography (CT) suggested duodenal stenosis, while the upper gastrointestinal endoscopy revealed mild gastritis and esophagitis without an obvious obstruction. SMA syndrome was included as a differential diagnosis and we performed another abdominal ultrasound, this time measuring the angle between the aorta and SMA which was 17°, and the distance between the two was 5 mm. We also asked the radiologist to perform the same measurements on the abdominal CT performed earlier and the results were compatible with our US findings. Thus, we establish the diagnosis of SMA syndrome, and the patient was managed conservatively. Results In this case, the abdominal US has proven to be the most useful tool in establishing the diagnosis and we suggest routine measurement of the aorta-SMA angle and distance in cases suggesting upper gastrointestinal obstruction. [ABSTRACT FROM AUTHOR]

Trauma and tumor compressing the brain distort underlying cortical neurons. Compressed cortical neurons remodel their dendrites instantly. The effects on axons however remain unclear. Using a rat epidural bead implantation model, we studied the effects of unilateral somatosensory cortical compression on its transcallosal projection and the reversibility of the changes following decompression. Compression reduced the density, branching profuseness and boutons of the projection axons in the contralateral homotopic cortex 1 week and 1 month post-compression. Projection fiber density was higher 1-month than 1-week post-compression, suggesting adaptive temporal changes. Compression reduced contralateral cortical synaptophysin, vesicular glutamate transporter 1 (VGLUT1) and postsynaptic density protein-95 (PSD95) expressions in a week and the first two marker proteins further by 1 month. βIII-tubulin and kinesin light chain (KLC) expressions in the corpus callosum (CC) where transcallosal axons traveled were also decreased. Kinesin heavy chain (KHC) level in CC was temporarily increased 1 week after compression. Decompression increased transcallosal axon density and branching profuseness to higher than sham while bouton density returned to sham levels. This was accompanied by restoration of synaptophysin, VGLUT1 and PSD95 expressions in the contralateral cortex of the 1-week, but not the 1-month, compression rats. Decompression restored βIII-tubulin, but not KLC and KHC expressions in CC. However, KLC and KHC expressions in the cell bodies of the layer II/III pyramidal neurons partially recovered. Our results show cerebral compression compromised cortical axonal outputs and reduced transcallosal projection. Some of these changes did not recover in long-term decompression. [ABSTRACT FROM AUTHOR]

We prospectively investigated in adults the decompression of dentigerous cysts associated with impacted third molars at high risk of iatrogenic damage during extraction. The computerised calculated volumetric postoperative reductions measured by cone-beam computed tomography at four and eight months were correlated with the duration of treatment, initial volume, and patient’s age. We prospectively monitored 14 adult patients with 14 dentigerous cysts that were associated with impacted third molars, for eight months after decompression. The mean (SD) reduction in volume during the first eight months was 71 (14) % (51% after the first four months and 20% after the second four months), with a monthly reduction rate of 9%. Both the total decrease in volume (a) and the monthly rate of reduction (b) were significantly associated (p < 0.01) and linearly correlated with the duration of decompression [r (a) = −0.89, r (b) = −0.61] and initial volume [r (a) = r (b) = 0.92], but not with the patient’s age (p = 0.49) [r (a) = r (b) = 0.04]. The trend towards reduction in volume within a period of eight months of treatment allowed us to better understand the duration of decompression required. [ABSTRACT FROM AUTHOR]

Patients with distal esophageal pathology such as perforation, trachea-esophageal fistulae, and/ or obstructing gastroesophageal junction tumor present a challenging situation in terms of feeding access where an esophageal stent is placed across the gastroesophageal junction. In order to allow simultaneous gastric decompression and post-pyloric feeds without significant reflux up through the stent, a gastrojejunostomy (GJ) tube is a viable option. We hereby describe a hybrid approach to placing these GJ tubes in this cohort of patients using simultaneous laparoscopy, endoscopy, and fluoroscopy with minimal manipulation of the stent itself. We have employed this technique of placing GJ tubes 2-3 days following placement of the esophageal stent in six consecutive patients. All patients tolerated the procedure well without any complications. Endoscopically guided laparoscopic GJ tubes are ideal for bridging patients, with distal esophageal pathology requiring esophageal stents, to oral intake. [ABSTRACT FROM AUTHOR]

Background Extreme lateral interbody fusion (ELIF) has gained popularity as a minimally invasive technique for indirect decompression. However, graft subsidence potentially threatens long-term success of ELIF. This study evaluated whether 26-mm-wide cages can eliminate subsidence and subsequent loss of decompression in ELIF. Methods Patients undergoing ELIF surgery using a 26-mm-wide cage were analyzed retrospectively. Patient demographics and perioperative data for radiographic and clinical outcomes were recorded. Radiographic parameters included regional sagittal lumbar lordosis and foraminal and disc height. Clinical parameters were evaluated using the Oswestry Disability Index and visual analog scale. Subsidence of 26-mm-wide cages was compared with previous outcomes of patients undergoing ELIF using 18-mm-wide and 22-mm-wide cages. Results There were 21 patients and 28 spinal segments analyzed. Radiographic outcome measures such as disc and foraminal height revealed significant improvement at follow-up compared with before surgery ( P = 0.001). Postoperative to last follow-up cage subsidence translated into 0.34 mm ± 0.26 and −0.55 mm ± 0.64 in disc and foraminal height loss, respectively. Patients with 26-mm-wide cages experienced less subsidence by means of disc (26 mm vs. 18 mm and 22 mm, P ≤ 0.05) and foraminal height (26 mm vs. 18 mm, P = 0.005; 26 mm vs. 22 mm, P = 0.208) loss compared with patients receiving 18-mm-wide and 22-mm-wide cages. Conclusions The 26-mm-wide cages almost eliminated cage subsidence in ELIF. Compared with 18-mm-wide and 22-mm-wide cages, 26-mm-wide cages significantly reduced cage subsidence in ELIF at midterm follow-up. A 26-mm-wide cage should be used in ELIF to achieve sustained indirect decompression. [ABSTRACT FROM AUTHOR]

Background Context: Laminectomy with posterior lumbar interbody fusion (PLIF) has been shown to achieve satisfactory clinical outcomes, but it leads to potential adverse consequences associated with extensive disruption of posterior bony and soft tissue structures.Purpose: This study aimed to compare the clinical and radiographic outcomes of bilateral decompression via a unilateral approach (BDUA) with transforaminal lumbar interbody fusion (TLIF) and laminectomy with PLIF in the treatment of degenerative lumbar spondylolisthesis (DLS) with stenosis.Study Design: This is a prospective cohort study.Patient Sample: This study compared 43 patients undergoing BDUA+TLIF and 40 patients undergoing laminectomy+PLIF.Outcome Measures: Visual analog scale (VAS) for low back pain and leg pain, Oswestry Disability Index (ODI), and Zurich Claudication Questionnaire (ZCQ) score.Methods: The clinical outcomes were assessed, and intraoperative data and complications were collected. Radiographic outcomes included slippage of the vertebra, disc space height, segmental lordosis, and final fusion rate. This study was supported by a grant from The National Natural Science Foundation of China (81572168).Results: There were significant improvements in clinical and radiographic outcomes from before surgery to 3 months and 2 years after surgery within each group. Analysis of leg pain VAS and ZCQ scores showed no significant differences in improvement between groups at either follow-up. The mean improvements in low back pain VAS and ODI scores were significantly greater in the BDUA+TLIF group than in the laminectomy+PLIF group. No significant difference was found in the final fusion rate at 2-year follow-up. The BDUA+TLIF group had significantly less blood loss, shorter length of postoperative hospital stay, and lower complication rate compared with the laminectomy+PLIF group.Conclusions: When compared with the conventional laminectomy+PLIF procedure, the BDUA+TLIF procedure achieves similar and satisfactory effects of decompression and fusion for DLS with stenosis. The BDUA+TLIF procedure appears to be associated with less postoperative low back discomfort and quicker recovery. [ABSTRACT FROM AUTHOR]

Background: Lumbar decompression surgery is often used to treat neurological symptoms of the lower extremity as a result of lumbar disease. However, this method also leads to the improvement of the accompanying low back pain (LBP). We studied the extent of LBP improvement after lumbar decompression surgery without fusion and the associated preoperative factors.Methods: Patients (n = 140) with lumbar spinal stenosis (n = 90) or lumbar disc herniation (n = 50) were included. To evaluate the change in LBP, VAS scores and the Oswestry disability index scores were measured before surgery and 2 weeks, 3 months, and 6 months after surgery. The predictors of residual LBP were investigated using logistic regression analyses.Results: In total, 140 patients were examined. The VAS scores for LBP before surgery and 2 weeks, 3 months, and 6 months after surgery were 4.4 ± 3.0 (mean ± standard deviation), 1.1 ± 1.5, 1.3 ± 1.8, and 1.9 ± 2.2, respectively. LBP significantly improved 2 weeks after surgery (P < 0.001), stabilized between 2 weeks and 3 months after surgery, but was significantly aggravated 3-6 months after surgery (P < 0.001). At 6 months after surgery, 67 (47.9%) patients had a VAS score of >1. The predictors of residual LBP included severe preoperative LBP, degenerative scoliosis and the size of the Cobb angle. The independent predictors, determined by multivariate analysis were degenerative scoliosis and the size of the Cobb angle.Conclusions: LBP was alleviated at 2 weeks after lumbar decompression surgery for lumbar disc herniation and lumbar spinal stenosis. The predictors of residual LBP after decompression included more severe LBP at baseline, degenerative scoliosis and the size of Cobb angle.Level Of Evidence: Level 3. [ABSTRACT FROM AUTHOR]

Background: The optimal treatment of neurological deficits following osteoporotic vertebral collapse (OVC) is controversial, owing to complications that result from fragile bone quality. In the present study, we assessed surgical results following posterior spinal fusion without decompression. We achieved stable fusion over a short segment of the spinal column using pedicle screws and spinous process plates, maximizing the use of the preserved posterior elements.Methods: We reviewed surgical data, perioperative complications, clinical outcomes, and radiographic data of 20 consecutively recruited patients with delayed neurological deficits following OVC, who experienced posterior short fusion without neural decompression. The average follow-up period was 24.3 months. The spine was typically stabilized with pedicle screws and spinous process plates from one level above to one level below the collapsed vertebrae, without using neural decompression or considerable correction of kyphosis.Results: All patients experienced relief from back pain and neurological improvements of at least one modified Frankel grade. Bone unions of the collapsed vertebrae were achieved in all patients, and spinal fusions of the instrumented segments were achieved in all but one patient. The mean loss of correction was 5.9°, and the average spinal canal compromise by bone fragments was 32.4% before surgery as against 26.0% at the final follow-up time point. Fractures in adjacent or upper instrumented vertebrae were observed in four cases (20%).Conclusions: Rigid augmentation by spinous process plates and an enough bed for the bone grafts were available in patients with severe osteoporosis, without neural decompression. All patients had satisfactory neurological recovery regardless of the extent of spinal canal remodeling, demonstrating that dynamic factors are the primary contributor to neurological deficits following OVC. [ABSTRACT FROM AUTHOR]

In the present work, a cryogenic mechanical property testing system conduction-cooled by two G-M cryocoolers was developed. The testing sample can be cooled from room temperature to 2.7 K within 7.5 h. The sample was first cooled down to 11.1 K directly by the two G-M cryocoolers and then cooled down to 2.7 K by decompressing the chamber. Instead of liquid helium, the cooling process is characterized by cooling with recycled helium gas as heat transfer medium. The heat load of the system was analyzed and optimizations were adopted in terms of material selections and design. The static load capacity of the system reaches 200 kN and the fatigue load capacity can reach 50 kN. This system can be installed onto an electronic universal testing machine or a fatigue testing machine to characterize static tension, fracture mechanics or fatigue properties at tunable low temperatures. Tensile properties of 316L austenitic stainless steels at 4.2 K were tested with the system and the results were compared with those obtained by cooled using liquid helium, which demonstrates high reliability. [ABSTRACT FROM AUTHOR]

Metapelitic rocks of the Jining Complex (sillimanite-cordierite-garnet (Sil–Crd–Grt) gneisses, sillimanite-garnet (Sil–Grt) gneisses and quartzofeldspathic rocks) are exposed in the eastern segment of the Khondalite Belt (KB) in the North China Craton (NCC). The Sil–Crd–Grt gneisses have preserved polyphase mineral assemblages and microstructural evidence of anatexis, resulting from biotite dehydration melting. Petrological observations revealed that the Sil–Crd–Grt gneisses contain three metamorphic assemblages: a peak assemblage of garnet porphyroblast and matrix biotite + sillimanite + K-feldspar + plagioclase + quartz + ilmenite + magnetite, a post-peak near-isothermal decompressional assemblage of garnet + cordierite + biotite + sillimanite + K-feldspar + plagioclase + quartz + ilmenite + magnetite, and a decompressional cooling assemblage of garnet + biotite + cordierite + K-feldspar + plagioclase + quartz + ilmenite + magnetite. A clockwise P – T path was defined involving the inferred peak stage followed by post-peak near-isothermal decompression and decompressional cooling stages, with P – T conditions of 790–825 °C and 9–10 kbar, 810–890 °C and 6.0–6.5 kbar, and 780–810 °C and 4.0–5.5 kbar, respectively. Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA–ICP–MS) U–Pb analyses of the Sil–Crd–Grt gneisses and Sil–Grt gneisses for the detrital and metamorphic zircons yielded a protolith age of ∼2.0 Ga and the late Paleoproterozoic metamorphic age of 1895–1885 Ma. The results reveal that the metapelitic rocks of the Jining Complex underwent continent–continent subduction or collision in the peak metamorphic stage, followed by a post-collisional exhumation event in the post-peak decompressional stage, and a subsequent decompressional cooling stage between the Yinshan and Ordos blocks to form the Paleoproterozoic KB. [ABSTRACT FROM AUTHOR]

Background Extreme lateral interbody fusion (ELIF) has gained popularity as a minimally invasive treatment allowing for indirect decompression of neural elements. However, evidence regarding the influence of facet degeneration (FD) and facet tropism (FT) toward indirect decompression is lacking. The aim of the study was to evaluate whether indirect decompression is impaired by FD and FT in patients undergoing ELIF. Methods Thirty-seven patients undergoing ELIF were included in a retrospective study. Radiographic parameters including disk height, segmental disk angle, foraminal area, FD, FT, and clinical outcome parameters (Oswestry Disability Index and Visual Analog Scale) were measured preoperatively and postoperatively. FD and FT were correlated with radiographic and clinical outcome parameters in order to determine predictors restricting indirect decompression. Results Thirty-seven patients with a total of 74 levels were analyzed. Clinical and radiographic outcome measures including central canal area (Δ = +17.2 mm 2 ), mean disk height (Δ = +3 mm), and foraminal area (Δ = +9.9 mm 2 ) revealed significant improvement compared with before surgery ( P ≤ 0.05). Patients with severe FD (grade 4) were more likely to have FT ≥ 12 degrees (32.3%) than patients without/mild (grades 0 and 1; 10%) or moderate FD (grades 2 and 3; 13%), P ≤ 0.05. FD and FT did not affect disk height restoration, foraminal area, canal surface area, or clinical outcome measures ( P ≥ 0.05). Conclusions Indirect decompression of neural elements in ELIF is not impaired by FD and FT are not relative contraindications in patients undergoing ELIF. [ABSTRACT FROM AUTHOR]

Background Even although microvascular decompression is the standard treatment for hemifacial spasm (HFS), the treatment is not always 100% successful. Some patients experience the reappearance of HFS after temporary relief after surgery. We analyzed our data to elucidate the reasons for and prognosis of HFS reappearance, specifically focusing on exact compressive location of the facial nerve. Methods The patients were divided into 2 groups: group A, the patients whose symptoms of spasm disappeared immediately after surgery but recurred within a month, and group B, the patients whose symptoms of spasm completely disappeared and never recurred. We adopted the terms of subdivision in the facial nerve root exit zone: RExP, root exit point; AS, attached segment; RDP, root detachment point; TZ, transition zone; and CP, distal cisternal portion. Results Among 115 patients, 56 (48.7%) belonged to group A and 59 (51.3%) to group B. In 54 of the 56 patients in group A (96.4%), the reappearing HFS disappeared gradually over several weeks. The precise location of compression in group A was at the RExP in 46.4% of the patients, AS in 33.9%, RDP in 16.1%, and TZ in 3.6%, and the RExP compression was significantly more frequent compared with in group B. Conclusions After microvascular decompression for HFS, almost half of the patients experienced transient HFS recurrence despite sufficient decompression of the facial nerve. However, in most cases, recurrent HFS gradually resolved over a period. Based on the compression location, the surgeon could anticipate recurrence of transient HFS. [ABSTRACT FROM AUTHOR]

Study Design: This is a systematic review.Purpose: The study aimed to evaluate whether spinal cord concussion (SCC) patients can safely return to play sports and if there are factors that can predict SCC recurrence or the development of a spinal cord injury (SCI).Background Context: Although SCC is a reversible neurologic disturbance of spinal cord function, its management and the implications for return to play are controversial.Methods: We conducted a systematic search of the literature using the keywords Cervical Spine AND Sports AND Injuries in six databases. We examined return to play in patients (1) without stenosis, (2) with stenosis, and (3) who underwent single-level anterior cervical discectomy and fusion (ACDF). We also investigated predictors for the risk of SCC recurrence or SCI.Results: We identified 3,655 unique citations, 16 of which met our inclusion criteria. The included studies were case-control studies or case series and reports. Two studies reported on patients without stenosis: pediatric cases returned without recurrence, whereas an adult case experienced recurrent SCC after returning to play. Seven studies described patients with stenosis. These studies included cases with and without recurrence after return to play, as well as patients who suffered SCI with permanent neurologic deficits. Three studies reported on patients who underwent an ACDF. Although some patients played after surgery without problems, several patients experienced recurrent SCC due to herniation at levels adjacent to the surgical sites. With respect to important predictors, a greater frequency of patients who experienced recurrence of symptoms or SCI following return to play had a "long" duration of symptoms (>24 hours; 36.36%) compared with those who were problem-free (11.11%; p=.0311).Conclusions: There is limited evidence on current practice standards for return to play following SCC and important risk factors for SCC recurrence or SCI. Because of small sample sizes, future prospective multicenter studies are needed to determine important predictive factors of poor outcomes following return to play after SCC. [ABSTRACT FROM AUTHOR]

Objective The scarcity of implants during the economic crisis partially has replaced decompression and instrumented fusion for the treatment of cervical spondylotic myelopathy with implant-less expansile cervical laminoplasty (ECL). The aim of the study was to compare the results obtained with instrumented anterior cervical corpectomy and fusion with implant-less ECL. Methods Patients suffering from cervical spondylotic myelopathy Nurick 3–5 with preoperative tethering and postoperative untethering were included. Exclusion criterion was kyphosis more than 10°. Patients were assessed according to 30-meter walking track (30mWT), Nurick, and modified Japanese Orthopaedic Association scale scores. Kinematic magnetic resonance imaging 3-dimensional subaxial spinal cord reconstructions were 3 dimensionally modeled to confirm preoperative pincer clamping and follow-up unclamping to measure subaxial spinal cord length and pia envelope area (PEA). Results A total of 35 patients divided in the ECL ( n = 19) and the anterior cervical corpectomy and fusion ( n = 16) groups were selected from 534 patients operated on between September 1, 2008, and August 31, 2013 as the result of degenerative cervical disorders. Patients improved according to Nurick and modified Japanese Orthopaedic Association scores without differences between groups. Follow-up 30mWT analysis showed greater decrease in steps number and time in ECL group, creating the basis for further imaging analysis. Magnetic resonance imaging analysis showed that spinal cord length (mm) shortened more (4.47 ± 1.87 vs. 1.5 ± 2.5, t = −4.02; P = 0.0003) and PEA (mm 2 ) shrank more (95.58 ± 43.73 vs. 22.94 ± 33.11, t = −5.45, P < 0.0001) in the ECL group. Multivariate logistic analysis showed that Δ 30mWT-time and Δ PEA were a very predictive model when area under the receiver operating characteristic curve is 0.98. Conclusions Our results created a nidus for further research of postdecompression spinal cord relaxation. [ABSTRACT FROM AUTHOR]

Purpose: Patients with pre-existing cervical spinal canal stenosis (CSCS) may have minimal or no symptoms. However, performing preventive decompression is controversial as the incidence of CSCS leading to severe cord injury is unknown. Hence, this study aims to revisit the threshold for surgery in "silent" CSCS by reviewing the neurologic outcomes of patients with undiagnosed CSCS who sustained a cervical spinal cord injury (CSCI).Methods: Two groups of subjects were recruited for analysis. Firstly, patients with trauma-induced CSCI without fracture or dislocation were included. Pre-existing CSCS was diagnosed by MRI measurements. The second group consisted of asymptomatic subjects recruited from the general population who also had MRIs performed. Canal sizes were compared between this control group and the patient group. Within the patient group, neurological assessments and outcomes by Frankel classification were performed in patients treated surgically or conservatively.Results: 32 patients with CSCS were recruited. The mean spinal canal sagittal diameter (disc-level) of all CSCS cases was 5.3 ± 1.4 mm (1.3-8.2). In comparison, the diameter was 10.5 ± 1.7 mm (6.6-14.6) in the 47 asymptomatic individuals recruited from the general population. Decompression was performed in 17 patients and conservative treatment in 15. Mean follow-up was 19.3 ± 17.0 months (6-84). At the final follow-up, 3 patients (9.3%) returned to their pre-injury Frankel grade, whereas 26 patients (83.3%) lost one or more neurological grade. Three patients (9.3%) died.Conclusions: Majority of patients with "silent" CSCS who sustained cervical cord injuries did not return to their pre-injury neurological status. All of these subjects have pre-existing canal stenosis hence the risk of cord injury. Given the poor neurological outcome of CSCS, a lower threshold for surgery could be indicated to avoid these disastrous injuries. However, before making any conclusive recommendation we must first identify the prevalence of "silent" CSCS in the general population and the risk of developing spinal cord injury with more prospective population-based studies. [ABSTRACT FROM AUTHOR]

To determine whether X90 steel pipe has enough crack arrest toughness or not, a damage model was suggested as crack arrest criterion with material parameters of plastic uniform percentage elongation and damage strain energy per volume. Fracture characteristic length which characterizes fracture zone size was suggested to be the largest mesh size on expected cracking path. Plastic uniform percentage elongation, damage strain energy per volume and fracture characteristic length of X90 were obtained by five kinds of tensile tests. Based on this criterion, a length of 24 m, Φ1219 × 16.3 mm pipe segment model with 12 MPa internal gas pressure was built and computed with fluid-structure coupling method in ABAQUS. Ideal gas state equation was used to describe lean gas behavior. Euler grid was used to mesh gas zone inside the pipe while Lagrangian shell element was used to mesh pipe. Crack propagation speed and gas decompression speed were got after computation. The result shows that, when plastic uniform percentage elongation is equal to 0.054 and damage strain energy per volume is equal to 0.64 J/mm 3 , crack propagation speed is less than gas decompression speed, which means the simulated X90 gas pipe with 12 MPa internal pressure can arrest cracking itself. [ABSTRACT FROM AUTHOR]

An original function describing the occurrence of indoor gas explosion in residential buildings has been presented in the paper. The function has been developed in order to simplify the description of explosion occurrence with its principal parameters, pressure and dynamics, being retained. It is a self-adaptative function, which means that its time function depends on the condition of construction elements, mainly decompressing areas called vents. The function consists of two parts. One is the phase of explosion pressure increase and the second is the decompression phase described by the f vent . modifier. The multiplication of the explosion pressure increase function and the f vent . modifier provides a final description of a pressure function for a vented explosion. The proposed function dependence enables an efficient dynamic analysis of three-dimensional models of building structures by means of the FEM. [ABSTRACT FROM AUTHOR]

Increasing venous return during cardiopulmonary resuscitation (CPR) has been shown to improve hemodynamics during CPR and outcomes following cardiac arrest (CA). We hypothesized that a high central venous pressure amplitude (CVP-A), the difference between the maximum and minimum central venous pressure during chest compressions, could serve as a robust predictor of return of spontaneous circulation (ROSC) in addition to traditional measurements of coronary perfusion pressure (CPP) and end-tidal CO 2 (etCO 2) in a porcine model of CA. After 10 min of ventricular fibrillation, 9 anesthetized and intubated female pigs received mechanical chest compressions with active compression/decompression (ACD) and an impedance threshold device (ITD). CPP, CVP-A and etCO 2 were measured continuously. All groups received biphasic defibrillation (200 J) at minute 4 of CPR and were classified into two groups (ROSC, NO ROSC). Mean values were analyzed over 3 min before defibrillation by repeated-measures Analysis of Variance and receiver operating characteristic (ROC). Five animals out of 9 experienced ROSC. CVP-A showed a statistically significant difference (p = 0.003) between the two groups during 3 min of CPR before defibrillation compared to CPP (p = 0.056) and etCO 2 (p = 0.064). Areas-under-the-curve in ROC analysis for CVP-A, CPP and etCO 2 were 0.94 (95% Confidence Interval 0.86, 1.00), 0.74 (0.54, 0.95) and 0.78 (0.50, 1.00), respectively. In our study, CVP-A was a potentially useful predictor of successful defibrillation and return of spontaneous circulation. Overall, CVP-A could serve as a marker for prediction of ROSC with increased venous return and thereby monitoring the beneficial effects of ACD and ITD. [ABSTRACT FROM AUTHOR]

Objective Post-operation of cervical decompression fusion and internal fixation (CDF) accelerated adjacent segment disc degeneration (ASD). It is not clear that whether instability of one single segmental accelerates the degeneration of adjacent segment disc. This study aims to explore the effect of cervical instability on the change of morphology and biochemistry in adjective segment (above) in the L5/6 cervical instability rabbit models. Methods Thirty-two mature New Zealand white rabbits (3000 ± 250 g) were randomly divided into two groups, control group (n = 8) and model group (n = 24). The animal models were established by destruction of partly annulus fibrosus and suction of nucleus pulposus. ASD was detected by X-ray after 4, 8 or 12 weeks surgery (8 model rabbits of each time). Animals were then euthanatized for cervical intervertebral disc tissue samples separation. Histomorphology, proteoglycan and collagen II of samples were detected. Results Histomorphology data showed that notochord cells were decreased in C4/5 cervical nucleus pulposus and were replaced by fibroblast-like cells; a small amount cartilage cells were emerged; intervertebral disc anulus fibrosus becomes rough, disorganized, hyaline degeneration and pigmentation, in which contained fibrocartilage cells and cracks between the inner and outer layers. Proteoglycan content of nucleus pulposus was significantly decreased. Meanwhile, type II collagen of nucleus pulposus and annulus was also apparently reduced. Conclusion Cervical instability can alter morphology and reduce the content of proteoglycan and collagen II in adjacent intervertebral disc, thereby contributes adjacent intervertebral disc degeneration. [ABSTRACT FROM AUTHOR]

Nanoscale gas bubbles are paid more and more attention due to their significant applications in different fields including the environmental remediation, plant and animal growth as well as medical diagnosis, etc. As reported, the local gas saturation plays an important role for the formation of surface nanobubbles (NBs) but is less importance for their stability. As for bulk NBs, few researches focused on the influence of dissolved gas on their generation and stability because it is thought generally that a limited amount of gas could dissolve into water. Herein, we reported for the first time the relationship of dissolved gases (Kr, O 2 and N 2) and the formation and stability of bulk NBs. Firstly, we developed a compression-decompression method to produce the water with super-high concentration of dissolved gas. About 60 mg/L oxygen dissolved gas was created to promote the formation of bulk NBs. It was showed that high bulk NB concentrations were produced using the compression-decompression method by controlling the loading pressure and time at the same time. The evolution process showed that the concentration of dissolved gas would decrease quickly with the deposited time. However, the concentration of formed bulk NBs did not follow the same way as dissolved gas concentration. It exhibited a complicated change over the time. Typically, first sharp increase to one order higher concentration than at the beginning and then decreased with a fluctuation within 72 h. More interestingly, the time of this sharp increase in nanobubble concentration depended on the type of gas, the krypton (Kr) gas system took longer time to reach the highest concentration and the oxygen (O 2) as well as nitrogen (N 2) gas system reached the highest concentration at about 4 h generally. The change of zeta potential of those NBs followed the same fluctuation as their concentration. Finally, we presumed a theoretical model to explain the evolution mechanism of bulk NBs. It indicated that there is a competition of different bubble behaviors (nucleation, clustering and coalescence) in different time periods. This study provides a new technique to produce high concentration of bulk NBs and dissolved gas in solution. Those results are very significance for further understanding the mechanism of formation and stability of bulk NBs under a super-high concentration of dissolved gas and may be used in some chemical reactions related with gas to promote the reaction efficiency. [Display omitted] [ABSTRACT FROM AUTHOR]

Background Microvascular decompression (MVD) represents the most effective and safe surgical option for the treatment of trigeminal neuralgia since it was first popularized by Jannetta 50 years ago. Despite several advances, complications such as cerebellar and vascular injury, hearing loss, muscular atrophy, cerebrospinal fluid (CSF) leak, postoperative cutaneous pain, and sensory disturbances still occur and may negatively affect the outcome. We propose some technical nuances of the surgical procedure that were used in our recent series. Methods We used a novel hockey stick−shaped retromastoid skin incision, preserving the major nerves of the occipital and temporal areas. Microsurgical steps were performed without the use of retractors. CSF leakage was prevented with a watertight dural closure and multilayer osteodural reconstruction. Results The refined surgical steps were perfected in the last consecutive 15 cases of our series. In these cases we did not record any cutaneous pain, sensory disturbances, or CSF leakage. The average diameter of the craniectomy was 18 mm. No patient reported major complications related to the intradural microsurgical maneuvers. In all cases the neurovascular conflict was found and solved with a good outcome in terms of pain disappearance. Conclusions Our minimally invasive approach was demonstrated to guarantee an optimal exposure of the cerebellopontine angle and minimize the rate of complications related to skin incision and muscular dissection, microsurgical steps, and closure. [ABSTRACT FROM AUTHOR]

Background The lumbar neural foraminal stenosis still is a challenging condition in minimally invasive spine surgery. Because of the anatomic situation a complete decompression of the nerve root often leads to a subtotal facetectomy associated with potential instability and the need for additional instrumentation of the decompressed segment. The iO-Flex system was introduced to address this problem by using a minimally invasive wire-guided microblade shaver to increase the neuroforaminal space by reducing the stenosis from intraforaminal while sparing bigger parts of the facet joint. In this study, we evaluated the feasibility and the surgical and radiological success in relation to the experience of the surgeon. Methods We performed decompression of the neuroforamen in 10 lumbar levels of 2 fresh-frozen human cadavers. Before and after decompression, we obtained high-resolution computed tomography data to evaluate the diameter of the neural foramen. Results The mean foraminal width (7.88–10.94 mm, P < 0.0001) and area (123.27–149.18 mm 2 , P < 0.003) increased significantly after the decompression, whereas the facet joints area (131.9–107.51 mm 2 , P < 0.005) and width (16.4–13.75 mm, P < 0.001) indeed decreased significantly but with an overall reduction of facet joint width by 16% and facet joint area by 18%. No complications such as nerve root damages or dural tears were observed. Conclusions The flexible micro blade shaver system is feasible with a steep learning curve and achieves sufficient decompression of the neuroforamen in this cadaveric study. [ABSTRACT FROM AUTHOR]

A novel approach to pre-slaughter stunning of chickens has been developed in which birds are rendered unconscious by progressive hypobaric hypoxia. Termed Low Atmospheric Pressure Stunning (LAPS), this approach involves application of gradual decompression lasting 280 s according to a prescribed curve. We examined responses to LAPS by recording behaviour, electroencephalogram (EEG) and electrocardiogram (ECG) in individual male chickens, and interpreted these with regard to the welfare impact of the process. We also examined the effect of two temperature adjusted pressure curves on these responses. Broiler chickens were exposed to LAPS in 30 triplets (16 and 14 triplets assigned to each pressure curve). In each triplet, one bird was instrumented for recording of EEG and ECG while the behaviour of all three birds was observed. Birds showed a consistent sequence of behaviours during LAPS (ataxia, loss of posture, clonic convulsions and motionless) which were observed in all birds. Leg paddling, tonic convulsions, slow wing flapping, mandibulation, head shaking, open bill breathing, deep inhalation, jumping and vocalisation were observed in a proportion of birds. Spectral analysis of EEG responses at 2 s intervals throughout LAPS revealed progressive decreases in median frequency at the same time as corresponding progressive increases in total power, followed later by decreases in total power as all birds exhibited isoelectric EEG and died. There was a very pronounced increase in total power at 50–60 s into the LAPS cycle, which corresponded to dominance of the signal by high amplitude slow waves, indicating loss of consciousness. Slow wave EEG was seen early in the LAPS process, before behavioural evidence of loss of consciousness such as ataxia and loss of posture, almost certainly due to the fact that it was completely dark in the LAPS chamber. ECG recordings showed a pronounced bradycardia (starting on average 49.6 s into LAPS), often associated with arrhythmia, until around 60 s into LAPS when heart rate levelled off. There was a good correlation between behavioural, EEG and cardiac measures in relation to loss of consciousness which collectively provide a loss of consciousness estimate of around 60 s. There were some effects of temperature adjusted pressure curves on behavioural latencies and ECG responses, but in general responses were consistent and very similar to those reported in previous research on controlled atmosphere stunning with inert gases. The results suggest that the process is humane (slaughter without avoidable fear, anxiety, pain, suffering and distress). In particular, the maintenance of slow wave EEG patterns in the early part of LAPS (while birds are still conscious) is strongly suggestive that LAPS is non-aversive, since we would expect this to be interrupted by pain or discomfort. [ABSTRACT FROM AUTHOR]

Core decompression is the most common procedure for treatment of the early stages of osteonecrosis of the femoral head. The purpose of this study was to compare the biomechanical performance of four different bone graft substitutes combined with core decompression. Subject-specific finite element models generated from computed tomography (CT) scan data were used for a comprehensive analysis. Two different contact conditions were simulated representing states of osseointegration at the interface. Our results showed that the use of a low-stiffness bone substitute did not increase the risk of femoral fracture in the early postoperative phase, but resulted in less micromotion and interfacial stresses than high-stiffness bone substitutes. [ABSTRACT FROM AUTHOR]

Objective Tarsal tunnel syndrome (TTS) is an entrapment neuropathy of the posterior tibial nerve in the tarsal tunnel. It is not known whether vascular or neuropathic factors are implicated in the cause of a cold sensation experienced by patients. Therefore, we studied the cold sensation in the pedal extremities of patients who did or did not undergo TTS surgery. Methods Our study population comprised 20 patients with TTS (38 feet); 1 foot was affected in 2 patients and both feet in 18 patients. We acquired the toe-brachial pressure index to evaluate perfusion of the sole and toe perfusion under 4 conditions: the at-rest position (condition 1); the at-rest position with compression of the foot dorsal artery (condition 2); the Kinoshita foot position (condition 3); and the Kinoshita foot position with foot dorsal artery compression (condition 4). Patients who reported abatement in the cold sensation during surgery underwent intraoperative reocclusion of the tibial artery to check for the return of the cold sensation. Results The toe-brachial pressure index for conditions 1 and 3 averaged 0.82 ± 0.09 and 0.81 ± 0.11, respectively; for conditions 2 and 4, it averaged 0.70 ± 0.11 and 0.71 ± 0.09, respectively. Among the 16 operated patients, the cold sensation in 7 feet improved intraoperatively; transient reocclusion of the tibial artery did not result in the reappearance of the cold sensation. Conclusions Our findings suggest that the cold sensation in the feet of our patients with TTS was associated with neuropathic rather than vascular factors. [ABSTRACT FROM AUTHOR]

Background Context: Degenerative lumbar stenosis (DLS) patients have been reported to lean forward in an attempt to provide neural decompression. Spinal alignment in patients with DLS may resemble that of adult spinal deformity (ASD). No previous studies have compared and contrasted the compensatory mechanisms of DLS and ASD patients.Purpose: This study aimed to determine the differences in compensatory mechanisms between DLS and ASD patients with increasing severity of sagittal spinopelvic malalignment. Contrasting these compensatory mechanisms may help determine at what severity sagittal malalignment represents a clinical sagittal deformity rather than a compensation for neural compression.Study Design/setting: This is a retrospective clinical and radiological review.Patient Sample: Baseline x-rays in patients without spinal instrumentation, with the clinical radiological and diagnoses of DLS or ASD, were assessed for patterns of spinopelvic compensatory mechanisms. Patients were stratified by sagittal vertical axis (SVA) according to the Scoliosis Research Society-Schwab [SRS-Schwab] classification.Outcome Measures: Radiographic spinopelvic parameters were measured in the DLS and ASD groups, including SVA, pelvic incidence-lumbar lordosis mismatch (PI-LL), T1 spinopelvic inclination (T1SPi), T1 pelvic angle (TPA), and pelvic tilt (PT).Methods: The two diagnosis cohorts were propensity-matched for PI and age. Each group contained 125 patients and was stratified according to the SRS-Schwab classification. Regional spinopelvic,lower limb, and global alignment parameters were assessed to identify differences in compensatory mechanisms between the two groups with differing degrees of deformity. No funding was provided by any third party in relation to carrying out this study or preparing the manuscript.Results: With mild to moderate malalignment (SRS-Schwab groups "0," or "+" for PT, PI-LL, or SVA), DLS patients permit anterior truncal inclination and recruit posterior pelvic shift instead of pelvic tilt to maintain balance, while providing relief of neurologic symptoms. Adult spinal deformity patients with mild to moderate deformity recruit pelvic tilt earlier than DLS patients. With moderate to severe malalignment, no significant difference was found in compensatory mechanisms between DLS and ASD patients.Conclusions: Patients with DLS permit mild to moderate deformity without recruiting compensatory mechanisms of PT, reducing truncal inclination and thoracic hypokyphosis to achieve neural decompression. However, with moderate to severe deformity, their desire for upright posture overrides the desire for neural decompression, evident by the adaptation of compensatory mechanisms similar to that of ASD patients. [ABSTRACT FROM AUTHOR]

The focus of the present work is the modeling of bubble growth on a hot plate during decompression (depressurization) of a volatile liquid at temperatures close to saturation and in the presence of dissolved gas. In particular, this work presents an organized attempt to analyze data obtained from an experiment under microgravity conditions. In this respect, a bubble growth mathematical model is developed and solved at three stages, all realistic under certain conditions but of increasing physical and mathematical complexity: At the first stage, the temperature variation both in time and space is ignored leading to a new semi-analytical solution for the bubble growth problem. At the second stage, the assumption of spatial uniformity of temperature is relaxed and instead a steady linear temperature profile is assumed in the liquid surrounding the bubble from base to apex. The semi-analytical solution is extended to account for the two-dimensionality of the problem. As the predictions of the above models are not in agreement with the experimental data, at the third stage an inverse heat transfer problem is set up. The third stage model considers an arbitrary average bubble temperature time profile and it is solved numerically using a specifically designed numerical technique. The unknown bubble temperature temporal profile is estimated by matching theoretical and experimental bubble growth curves. A discussion follows on the physical mechanisms that may explain the evolution of the average bubble temperature in time. [ABSTRACT FROM AUTHOR]

Aim: Chest compressions during cardiopulmonary resuscitation (CPR) increase arterial and venous pressures, delivering simultaneous bidirectional high-pressure compression waves to the brain. We hypothesized that this may be detrimental and could be partially overcome by elevation of the head during CPR.Measurements: Female Yorkshire farm pigs (n=30) were sedated, intubated, anesthetized, and placed on a table able to elevate the head 30° (15cm) (HUP) and the heart 10° (4cm) or remain in the supine (SUP) flat position during CPR. After 8minutes of untreated ventricular fibrillation and 2minutes of SUP CPR, pigs were randomized to HUP or SUP CPR for 20 more minutes. In Group A, pigs were randomized after 2minutes of flat automated conventional (C) CPR to HUP (n=7) or SUP (n=7) C-CPR. In Group B, pigs were randomized after 2minutes of automated active compression decompression (ACD) CPR plus an impedance threshold device (ITD) SUP CPR to either HUP (n=8) or SUP (n=8).Results: The primary outcome of the study was difference in CerPP (mmHg) between the HUP and SUP positions within groups. After 22minutes of CPR, CerPP was 6±3mmHg in the HUP versus -5±3 in the SUP (p=0.016) in Group A, and 51±8 versus 20±5 (p=0.006) in Group B. Coronary perfusion pressures after 22minutes were HUP 6±2 vs SUP 3±2 (p=0.283) in Group A and HUP 32±5 vs SUP 19±5, (p=0.074) in Group B. In Group B, 6/8 pigs were resuscitated in both positions. No pigs were resuscitated in Group A.Conclusions: The HUP position in both C-CPR and ACD+ITD CPR significantly improved CerPP. This simple maneuver has the potential to improve neurological outcomes after cardiac arrest. [ABSTRACT FROM AUTHOR]

Moldavites, tektites of the Central European strewn field, have been traditionally linked with the Ries impact structure in Germany. They are supposed to be derived mainly from the near-surface sediments of the Upper Freshwater Molasse of Miocene age that probably covered the target area before the impact. Comparison of the chemical composition of moldavites with that of inferred source materials requires recalculation of the composition of sediments to their water-, organic carbon- and carbon dioxide-free residuum. This recalculation reflects the fact that these compounds were lost almost completely from the target materials during their transformation to moldavites. Strong depletions in concentrations of many elements in moldavites relative to the source sediments (e.g., Mo, Cu, Ag, Sb, As, Fe) contrast with enrichments of several elements in moldavites (e.g., Cs, Ba, K, Rb). These discrepancies can be generally solved using two different approaches, either by involvement of a component of specific chemical composition, or by considering elemental fractionation during tektite formation. The proposed conceptual model of moldavite formation combines both approaches and is based on several steps: (i) the parent mixture (Upper Freshwater Molasse sediments as the dominant source) contained also a minor admixture of organic matter and soils; (ii) the most energetic part of the ejected matter was converted to vapor (plasma) and another part produced melt directly upon decompression; (iii) following further adiabatic decompression, the expanding vapor phase disintegrated the melt into small melt droplets and some elements were partially lost from the melt because of their volatility, or because of the volatility of their compounds, such as carbonyls of Fe and other transition metals (e.g., Ni, Co, Mo, Cr, and Cu); (iv) large positively charged ions such as Cs + , Ba 2+ , K + , Rb + from the plasma portion were enriched in the late-stage condensation spherules or condensed directly onto negatively charged melt droplets; (v) simultaneously, the melt droplets coalesced into larger tektite bodies. Steps (iii)–(v) may have overlapped in time. The still melted moldavite bodies reaching their final size were reshaped by further melt flow. This melt flow was related to moldavite rotation and escape (bubbling off) of the last portion of gaseous volatiles during their flight in a low-pressure region above the dense layer of the atmosphere. [ABSTRACT FROM AUTHOR]

Objective In surgery for acute subdural hematoma (ASDH), the bone flap can be fixed onto the skull, left riding to provide partial skull decompression, or removed. This study assessed whether removing the bone flap improved outcome. Methods We conducted an observational study on consecutive patients who were operated for ASDH in our hospital from July 2011 to June 2014. We retrospectively collected data on demographics, injury severity, and predicted and observed outcomes at 6 months. The cohort was divided into 2 groups based on whether the bone flap was replaced (fixed and riding flap craniotomy) or removed (decompressive craniectomy). The differences in functional status, postoperative control of intracranial hypertension, and number of cranial reoperations were analyzed. A subgroup analysis compared decompressive craniectomy with riding flap craniotomy alone. Results Data were obtained for 99 patients; 69 had decompressive craniectomy, 17 had riding flap craniotomy, and 13 had fixed flap craniotomy. The decompressive craniectomy group had statistically worse injuries, more predicted poor outcomes (69% vs. 57%, P = 0.013), more observed poor outcomes (59% vs. 37%, P = 0.037), equivalent control of intracranial hypertension, and a similar number of reoperations compared with the craniotomy groups. Subgroup analysis between decompressive craniectomy and riding flap craniotomy showed no significant difference in baseline characteristics and outcomes. Conclusions Our study concluded that removing the bone flap after ASDH evacuation was not associated with a better outcome. We recommend replacing the bone flap if brain conditions allow. Further research is required to evaluate the role of skull decompression in surgery for ASDH. [ABSTRACT FROM AUTHOR]

We propose a kinetic model that statistically describes the growth by decompression, exsolution and coalescence of a polydisperse population of gas bubbles in a silicate melt. The model is homogeneous in space and its main variable is a distribution function representing the probability to find a bubble of volume v and mass m at time t . The volume and mass growth rates are described by a simplification of the classical monodisperse bubble growth model. This simplification, which shortens computational time, removes the coupling between mass evolution and an advection–diffusion equation describing the behavior of the volatile concentration in the melt. We formulate three coalescence mechanisms: thinning of the inter-bubble planar films, film deformation by differential bubble pressure, and buoyancy-driven collision. Numerical simulations based on a semi-implicit numerical scheme show a good agreement between the coalescence-free runs and the monodisperse runs. When coalescence is introduced, numerical results show that coalescence kernels based on different physical mechanisms yield distinct evolutions of the size distributions. A preliminary comparison between runs and experimental data suggests a qualitative match of two out of the three proposed kernels. This kinetic model is thus a powerful tool that can help in assessing how bubble growth and coalescence occur in magmas. [ABSTRACT FROM AUTHOR]