Methane fueled lake pelagic food webs in a Cretaceous greenhouse world.

Methane (CH4) is a potent greenhouse gas but also an important carbon and energy substrate for some lake food webs. Understanding how CH4 incorporates into food webs is, therefore, crucial for unraveling CH4 cycling and its impacts on climate and ecosystems. However, CH4-fueled lake food webs from pre-Holocene intervals, particularly during greenhouse climates in Earth history, have received relatively little attention. Here, we present a long-term record of CH4-fueled pelagic food webs across the Cretaceous Oceanic Anoxic Event 1a (~120 Mya) that serves as a geological analog to future warming. We show an exceptionally strong expansion of both methanogens and CH4-oxidizing bacteria (up to 87% of hopanoid-producing bacteria) during this Event. Grazing on CH4-oxidizing bacteria by zooplankton (up to 47% of ciliate diets) within the chemocline transferred substantial CH4-derived carbon to the higher trophic levels, representing an important CH4 sink in the water column. Our findings suggest that as Earth warms, microbial CH4 cycling could restructure food webs and fundamentally alter carbon and energy flows and trophic pathways in lake ecosystems.

Evolution and Screening of Trichoderma reesei Mutants for Secreted Protein Production at Elevated Temperature.

The filamentous fungus Trichoderma reesei is a mesophilic ascomycete commercially used to produce industrial enzymes for a variety of applications. Strain improvement efforts over many years have resulted in more productive hosts, but also in undesirable traits such as the need for lower temperatures to achieve maximum protein secretion rates. Lower fermentation temperatures increase the need for cooling resulting in higher manufacturing costs. We used a droplet-based evolution strategy to increase the protein secretion temperature of a highly productive T. reesei whole cellulase strain from 25°C to 28°C by first isolating an improved mutant and subsequently tracing the causative high temperature mutation to one gene designated gef1. An industrial host with a gef1 deletion was found to be capable of improved productivity at higher temperature under industrially relevant fermentation conditions.

Impact of postoperative spinal malalignment on postoperative health-related quality of life after long-level fixation for degenerative lumbar scoliosis: does residual coronal angularity matter?

PURPOSE: This study evaluates the influence of spinal malalignment on health-related quality of life (HRQOL) in a long-level fusion spine. METHODS: This was a retrospective analysis of 121 consecutive patients with DLS after long-segment fusion. HRQOL and radiographic parameters were collected at final follow-up. For postoperative residual Cobb angle (CA), patients were divided as follows: group (0) (CA < 10°), group (+) (CA 10°âˆ¼20 °), and group (++) (CA > 20°). For postoperative coronal vertical axis (CVA), patients were separated as follows: group (0) (CVA < 2 cm), group (+) (CVA 2 ∼ 3 cm), and group (++) (CVA > 3 cm). Patients were also grouped by the sagittal modifiers as group (0), group (+), and group (++) according to the Scoliosis Research Society (SRS)-Schwab classification, respectively. RESULTS: Visual analog scale (VAS) for back was significantly lower in CA 10°âˆ¼20° group compared to other groups. Patients with remnant CA > 20° showed worse Oswestry Disability Index (ODI), SRS-22 and the 36-item Short Form Health Survey (SF-36) - physical component scores (PCS). Sagittal vertical axis (SVA) showed significant correlation with HRQOLs after surgery, and the statistical significance of ODI, SRS-22 and SF-36 scores was observed among subgroups. CONCLUSIONS: In long-level fused spine, residual CA > 20° resulted in worse clinical outcomes and was recommended to avoid during surgery. And 10° to 20° residual CA was acceptable in DLS patients and even better than Cobb angle < 10° in several HRQOLs, therefore strictly pursing upright alignment seems unnecessary. SVA also showed effectiveness in assessing HRQOL in the fixed spine.

Stiffness-related disability following long segmental posterior instrumentation and fusion: is it influenced by postoperative spinopelvic alignment?

PURPOSE: The aims of this study were to investigate the correlations between Chinese version of Lumbar Stiffness Disability Index (C-LSDI) and other clinical outcomes, and to identify the factors independently affecting stiffness-related disability after long-segment fusion in patients with degenerative lumbar scoliosis (DLS). METHODS: We performed a retrospective study of 118 consecutive surgically treated DLS cases at a single institute. Pre- and post-operative radiological parameters and postoperative health related quality of life (HRQOL) were examined to determine their correlation coefficients with postoperative C-LSDI. Patients were divided into two groups by the medium number of postoperative C-LSDI: low-stiffness group (C-LSDI < 48 points) and high-stiffness group (C-LSDI ≥ 48 points). Subsequently, differences between the two groups were assessed, and the presumed factors affecting C-LSDI evaluation were further analyzed. RESULTS: Coronal parameters and global sagittal parameters showed significant correlations with postoperative C-LSDI. The correlation coefficients between C-LSDI and Oswestry Disability Index (ODI), Japanese Orthopedic Association-29 (JOA-29), the Scoliosis Research Society-22 questionnaire (SRS-22) Function, and the Short Form-36 Health Survey (SF-36) Physical Component Scores were over 0.5. In multiple linear regression, postoperative sagittal vertical axis (ß = 0.084, p = 0.025), fusion levels (ß = 2.13, p = 0.012), and body mass index (ß = 0.867, p = 0.022) were independent related factors for C-LSDI. CONCLUSION: This study showed that all HRQOLs demonstrated the varying degree of correlations with C-LSDI, of which the ODI, JOA-29, SRS-22 Function, and SF-36 PCS were most relevant, with moderate strength of associations.Moreover, longer fusion levels, higher BMI, and greater postoperative SVA independently affect C-LSDI after long segmental posterior instrumentation and fusion for DLS.

Sizable spin-to-charge conversion in PLD-grown amorphous (Mo, W)Te2-xfilms.

We report on the spin-to-charge conversion (SCC) in Mo0.25W0.75Te2-x(MWT)/Y3Fe5O12(YIG) heterostructures at room temperature. The centimeter-scale amorphous MWT films are deposited on liquid-phase-epitaxial YIG by pulsed laser deposition technique. The significant SCC voltage is measured in the MWT layer with a sizable spin Hall angle of ∼0.021 by spin pumping experiments. The control experiments by inserting MgO or Ag layer between MWT and YIG show that the SCC is mainly attributed to the inverse spin Hall effect rather than the thermal or interfacial Rashba effect. Our work provides a novel spin-source material for energy-efficient topological spintronic devices.

Clinical progression of ossification of the ligamentum flavum in thoracic spine: a 10- to 11-year follow-up study.

BACKGROUND: Thoracic ossification of ligamentum flavum (TOLF) can be asymptomatic and progress insidiously. But, long-term follow-up results of clinical progression of TOLF are still unknown. METHODS: The clinical progression of 81 patients with TOLF at our center, followed for 10 to 11 (mean, 10.3) years from May 2010 to November 2021, were analyzed. Among them, 51 patients with thoracic myelopathy were caused by single- or multi-segment TOLF, and received partial TOLF resection (30 patients) or total TOLF resection (21 patients). The remaining 30 patients showed TOLF on imaging examinations, but TOLF was not the responsible compressing factor causing myelopathy and with no TOLF resection. The mJOA score (total 11 scores) and spinal operation were used to evaluate the clinical progression at follow-up. RESULTS: During the 10- to 11-year follow-up of 81 TOLF patients, 71 (87.7%) had no deterioration of neurological function, and 10 (12.3%) patients had deterioration of neurological function and had another spinal operation, including only 4 (4.9%) suffered thoracic myelopathy caused by the progression of TOLF; 6 (7.4%) for other spinal diseases: 2 (2.5%) had fall damage and acute spinal cord injury at the TOLF level; 2 (2.5%) had thoracic myelopathy caused by ossification of posterior longitudinal ligament (OPLL); 2 (2.5%) had cervical spondylosis and received cervical operation. CONCLUSIONS: Most TOLF (87.7%) patients had no clinical progression and received no reoperations for TOLF in the ten-year dimension (mean, 10.3 years). Narrow spinal canal for TOLF increases the risk of traumatic paraplegia.

Clinical and radiographic features of adult calcified thoracic disc herniation: a retrospective analysis of 31 cases.

PURPOSE: To analyze the clinical and radiographic characteristics of calcified thoracic disc herniation (CTDH) and explore the possible pathogeneses. METHODS: This is a retrospective clinical review of prospectively collected imaging data based at a single institute from 2004 to 2021. Clinical and radiographic parameters of CTDH patients were retrospectively collected and analyzed. RESULTS: All 31 patients included presented thoracic myelopathy with a 17.05-month preoperative disease duration. Three (9.7%) patients had a history of trauma, and the rest had insidious onset. The average spinal canal ventral-occupying ratio was 74.90 ± 15.16%. The most prominent radiographic feature was the calcification of the nucleus pulposus in the intervertebral disc and the calcified lesion contiguous with the disc space protruding into the spinal canal. Three main imaging forms of CTDH were found: calcium-ringed lesion (5), heterogeneous calcification lesion (19), and homogeneous calcification lesion (7). The radiographic manifestations, intraoperative findings, and postoperative pathologies of the three subtypes were different. The calcium-ringed lesion type was younger and had a shorter preoperative duration and significantly lower mJOA score. A special case was observed conservatively for five years, which suggested that a heterogeneous lesion could progress to a homogeneous lesion. CONCLUSIONS: Adult CTDH is a special thoracic disc disease with insidious onset, a long course, and a high spinal canal-occupying ratio. Calcium deposits in the spinal canal originate from the nucleus pulposus. The intraoperative findings and postoperative pathology of subtypes are different, which might indicate different pathological mechanisms.

Robot-assisted percutaneous vertebroplasty for osteoporotic vertebral compression fractures: a retrospective matched-cohort study.

PURPOSE: This study aims to introduce the principle, clinical efficacy, and learning curve of robot-assisted percutaneous vertebroplasty (PVP). METHODS: Forty-two patients who underwent robot-assisted single-level PVP were analyzed retrospectively and 42 age-matched patients using freehand technique were selected as the control group. The visual analog scale, operation time, radiation exposure, accuracy, and learning curve were analyzed. RESULTS: The puncture time and total operation time were significantly shorter, and the puncture and total fluoroscopy number were fewer in the robot group. The deviation between pre-operative planned and actual puncture trajectory well met clinical requirement. The puncture time, total operation time, and puncture fluoroscopy number were significantly more in early cases than in later cases in the robot group. CONCLUSION: The robot-assisted pedicle puncture technique shortens the operation time and reduces radiation exposure, and the accuracy meets the clinical requirement in PVP. The learning curve is short and not steep.

LGR5 regulates osteogenic differentiation of human thoracic ligamentum flavum cells by Wnt signalling pathway.

Thoracic ossification of the ligamentum flavum (TOLF) is ectopic ossification of the spinal ligaments. Histologically, the development of TOLF can be described as the process of endochondral ossification. However, the underlying aetiology has not been completely clarified. In this investigation, the gene expression profile associated with leucine-rich repeat-containing G-protein-coupled receptors (LGR) and Wnt signalling pathway in the thoracic ligamentum flavum cells (TLFCs) of different ossification stages was analysed via RNA sequencing. We further confirmed the significant differences in the related gene expression profile by Gene Ontology (GO) enrichment analysis. LGR5 was first identified in primary human TLFCs during osteogenic differentiation. To evaluate the effect of LGR5 on osteogenic differentiation, LGR5 has been knocked down and overexpressed in human TLFCs. We observed that the knockdown of LGR5 inhibited the activity of Wnt signalling and attenuated the potential osteogenic differentiation of TLFCs, while overexpression of LGR5 activated the Wnt signalling pathway and increased osteogenic differentiation. Our results provide important evidence for the potent positive mediatory effects of LGR5 on osteogenesis by enhancing the Wnt signalling pathway in TOLF.

Significance of body mass index on thoracic ossification of the ligamentum flavum in Chinese population.

PURPOSE: To investigate the risk factors for thoracic ossification of the ligamentum flavum (TOLF), especially the relationship between BMI and TOLF. METHODS: A total of 856 individuals consisting of 326 controls without ossification of spinal ligaments and 530 TOLF inpatients who underwent thoracic spine decompression surgery at our hospital between January 2013 and September 2020 were included. All subjects were classified into 4 grades: Grade 0) control; Grade 1) single-segment TOLF; Grade 2) multi-segment TOLF; and Grade 3) TOLF combined thoracic ossification of the posterior longitudinal ligament (T-OPLL). Logistic regression analysis was performed to identify the risk factors for TOLF. The TOLF index was calculated to assess the severity of TOLF, and its relationship with BMI was investigated by correlation analysis. RESULTS: Overall, TOLF patients are most numerous in the 50-59 age group. Age and gender were considered as independent risk factors for Grades 1 and 2. BMI was identified as an independent risk factor for TOLF. Furthermore, BMI was significantly higher in Grade 1 (26.1 VS 24.5 kg/m2, P = 0.0001), Grade 2 (28.2 VS 24.5 kg/m2, P < 0.0001), and Grade 3 (29.1 VS 24.5 kg/m2, P < 0.0001) than Grade 0. Notably, in TOLF patients without combined T-OPLL, BMI was positively correlated with TOLF index, while BMI was negatively correlated with age in younger individuals. CONCLUSION: BMI is a crucial risk factor for TOLF. It highlights the necessity of close follow-up of asymptomatic TOLF patients with high BMI to detect and treat their TOLF progression promptly.

Banner cloud sign: a novel method for the diagnosis of dural ossification in patients with thoracic ossification of the ligamentum flavum.

PURPOSE: Dural ossification (DO) is common in patients with ossification of the ligamentum flavum (OLF) and is the leading cause of dural tears. However, the methods used for DO diagnosis are limited. The purpose of this study was to propose a novel CT-based imaging sign, Banner cloud sign (BCs), and clarify its clinical characteristics and correlations with DO. METHODS: 57 OLF patients who underwent thoracic spine decompression surgery in our single-center between January- and October-2018 were recruited and divided into two groups based on the presence of DO. Patient demographics and radiographic data were analyzed. Hematoxylin-eosin staining and micro-CT were used to detect the micro-morphological changes of DO. The diagnostic value of BCs for DO was assessed by sensitivity and specificity. RESULTS: 12 patients with a total of 19 segments were diagnosed as DO. The incidence of DO was 21.1% (12/57) in OLF patients and 9.5% (19/200) in OLF segments. Patients with DO had a shorter disease duration and a higher incidence of cerebrospinal fluid leakage than those without DO. Hematoxylin-eosin staining and micro-CT showed that the dura mater was ossified and fused with ossified ligamentum flavum, and diffusion along the dura mater, like a banner cloud flying on the mountain. The sensitivity and specificity of BCs in DO diagnosis were 78.9 and 90.6%, respectively. CONCLUSION: BCs can vividly and intuitively describe the imaging features of DO and has high diagnostic accuracy. It could be a promising and valuable method for the diagnosis of DO.

Scoliosis in dysplastic spondylolisthesis: a clinical survey of 50 young patients.

BACKGROUND: Dysplastic spondylolisthesis is a rare spinal deformity that occurs mainly in young patients. Although its sagittal parameters had been well stated, coronal abnormalities in these patients were poorly studied. The purposes of this study were: (1) to investigate the prevalence of scoliosis in dysplastic spondylolisthesis;(2) to assess scoliosis resolution or persistence after surgery; and (3) to propose a modified classification of scoliosis associated with dysplastic spondylolisthesis. METHODS: Fifty patients (average age 14.9 ± 5.6 years) diagnosed with dysplastic spondylolisthesis who underwent surgical treatment were followed up and their data were analyzed. Standing posteroanterior and lateral full spine radiographs were used to measure the coronal and sagittal parameters. Patients with scoliosis, which was defined as a coronal Cobb angle greater than 10°, were divided into three groups according to their curve characteristics: "independent" scoliosis (IS) group, spasm scoliosis (SS) group, and olisthetic scoliosis (OS) group. SS and OS were spondylolisthesis-induced scoliosis. The radiographic parameters and patient-reported outcomes were collected before and after surgery and compared between groups. RESULTS: The average slip percentage was 62.8% ± 23.1% and the average follow-up time was 51.5 ± 36.4 months (range 3-168 months). Twenty-eight of the 50 (56%) dysplastic spondylolisthesis patients showed scoliosis, of which 8 were IS (24.7° ± 15.2°), 11 were SS (13.9° ± 3.0°), and 9 were OS (12.9° ± 1.9°). By the last follow-up, no scoliosis resolution was observed in the IS group whereas all SS patients were relieved. Of the nine patients with OS, four (44.4%) had scoliosis resolution after surgery. CONCLUSION: Distinguishing different types of scoliosis in dysplastic spondylolisthesis patients may help surgeons to plan treatment and understand prognosis. For patients with significant scoliosis, whether "independent" or spondylolisthesis-induced, treatment of spondylolisthesis should be performed first and scoliosis should be observed for a period of time and treated according to the corresponding principles.

Ecological dynamics of terrestrial and freshwater ecosystems across three mid-Phanerozoic mass extinctions from northwest China.

The Earth has been beset by many crises during its history, and yet comparing the ecological impacts of these mass extinctions has been difficult. Key questions concern the kinds of species that go extinct and survive, how communities rebuild in the post-extinction recovery phase, and especially how the scaling of events affects these processes. Here, we explore ecological impacts of terrestrial and freshwater ecosystems in three mass extinctions through the mid-Phanerozoic, a span of 121 million years (295-174 Ma). This critical duration encompasses the largest mass extinction of all time, the Permian-Triassic (P-Tr) and is flanked by two smaller crises, the Guadalupian-Lopingian (G-L) and Triassic-Jurassic (T-J) mass extinctions. Palaeocommunity dynamics modelling of 14 terrestrial and freshwater communities through a long sedimentary succession from the lower Permian to the lower Jurassic in northern Xinjiang, northwest China, shows that the P-Tr mass extinction differed from the other two in two ways: (i) ecological recovery from this extinction was prolonged and the three post-extinction communities in the Early Triassic showed low stability and highly variable and unpredictable responses to perturbation primarily following the huge losses of species, guilds and trophic space; and (ii) the G-L and T-J extinctions were each preceded by low-stability communities, but post-extinction recovery was rapid. Our results confirm the uniqueness of the P-Tr mass extinction and shed light on the trophic structure and ecological dynamics of terrestrial and freshwater ecosystems across the three mid-Phanerozoic extinctions, and how complex communities respond to environmental stress and how communities recovered after the crisis. Comparisons with the coeval communities from the Karoo Basin, South Africa show that geographically and compositionally different communities of terrestrial ecosystems were affected in much the same way by the P-Tr extinction.

Association Between Clinical Symptoms and Radiographic Features in Late-Stage Knee Osteoarthritis Using a New Radiographic Parameter.

OBJECTIVE: In this study, we proposed a new radiographic parameter, the plateau attrition index (PAI), and the PAI grades (PAIs) to explore the relationship between subchondral attrition of the tibial plateau and symptoms of knee osteoarthritis (OA) in patients with late-stage knee osteoarthritis. METHOD: One hundred nineteen patients with late-stage knee osteoarthritis were enrolled. The Kellgren and Lawrence (K/L) grades and hip-knee-ankle (HKA) angle were used to characterize the radiographic features of knee OA. The bone attrition of the tibial plateau was determined by the PAI and PAIs. The symptoms of knee OA were assessed by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), which is composed of the WOMAC pain (WOMP), WOMAC stiffness (WOMS), and WOMAC function (WOMF) subscores. WOMAC pain scores were divided into non-weight-bearing pain (NWBP) and weight-bearing pain (WBP) subcategories. The Pearson correlation coefficient was used to determine the relationship between the PAI, HKA angle, and WOMAC scores. The Spearman rank correlation coefficient was used to evaluate the correlation between the WOMAC score and the PAIs and K/L grades. RESULTS: The distribution of the WOMAC scores according to the PAIs was significant (P < .01). A positive correlation was identified between the PAI and the WOMAC, WOMP, WOMF and WBP scores (r = 0.29, 0.34, 0.26 and 0.34, P < .01, respectively). In addition, the PAIs was also significantly correlated with the WOMAC, WOMP, WOMF, and WBP scores (r = 0.37, 0.38, 0.35 and 0.44, P < .01, respectively). CONCLUSIONS: The attrition of tibial subchondral bone determined by the new parameter, the plateau attrition index, was correlated with symptoms, especially weight-bearing pain in late-stage knee OA.

Cost-Benefit Analysis of Using A Single Dose of Tranexamic Acid in Degenerative Lumbar Scoliosis Patients Undergoing Long-Segment Spinal Fusion Surgery: A Retrospective Study.

BACKGROUND Degenerative lumbar scoliosis (DLS) patients undergoing posterior long-segment spinal fusion surgery often require perioperative blood transfusions, and previous studies have reported that increased complications and additional costs accompany these transfusions. One method for decreasing transfusions is the administration of tranexamic acid (TXA). We sought to evaluate the costs and benefits of preoperative administration of 1 g of intravenous TXA, without maintenance, in DLS patients undergoing long-segment spinal fusion surgery. MATERIAL AND METHODS Patients who received TXA (TXA group) were compared with patients who did not receive TXA (NTXA group) with regard to blood loss, units of packed red blood cells (PRBC) transfused, hemostasis costs, and perioperative complications. The benefits and costs were estimated through analysis of the spending on NTXA and TXA patients, and were compared. The difference between the cost per patient in the 2 groups was designated as the net cost-benefit. Then, both groups were substratified into non-osteotomy and osteotomy subgroups for further analysis. RESULTS Of the 173 patients who met the inclusion criteria, 54 TXA patients had significantly reduced perioperative blood loss and total hemostasis costs compared with NTXA patients (n=119). In the group without osteotomy (n=72), TXA (n=13) reduced perioperative blood loss but did not significantly decrease PRBC units and hemostasis costs. However, in patients undergoing osteotomy (n=101), a remarkable net cost savings of ¥648.77 per patient was shown in the TXA group (n=41) (P<0.001). This was because patients undergoing osteotomy in the TXA group received fewer PRBC units (3.7 vs 5.7, P=0.001). CONCLUSIONS A single dose of TXA significantly decreased perioperative blood loss and total hemostasis costs for DLS patients undergoing osteotomy. Furthermore, TXA led to no additional net costs in patients without osteotomy.

Association analysis and functional study of COL6A1 single nucleotide polymorphisms in thoracic ossification of the ligamentum flavum in the Chinese Han population.

PURPOSE: Genetic factors play a crucial role in thoracic ossification of the ligamentum flavum (TOLF). This study aimed to better understand the association between single nucleotide polymorphisms (SNP) in functional regions of the collagen VI, alpha 1 gene (COL6A1) and TOLF, and to confirm COL6A1 as a TOLF susceptibility gene. METHODS: Ten tag SNPs in COL6A1 were genotyped using the SNaPshot assay, and allele and genotype frequencies were compared between TOLF patients and control individuals. The function of SNPs associated with disease was studied. For COL6A1 promoter SNPs, the transcriptional activity of each haplotype was determined by luciferase reporter assays. For COL6A1 exonic SNPs, the effect of nucleotide substitutions on COL6A1 expression was determined by western blotting. COL6A1 mRNA expression in ligamentum flavum tissues from TOLF patients with different genotypes was examined using reverse transcription real-time PCR. RESULTS: Four SNPs were associated or possibly associated with TOLF, with higher pathogenic allele and genotype frequencies seen in TOLF patients compared with controls. The rs17551710/rs7671-GG/GG genotype appeared to be related to disease severity. Nucleotide substitutions at rs17551710 and rs7671 increased COL6A1 transcriptional activity and nucleotide substitutions at rs1053312 and rs13051496 increased COL6A1 protein expression. COL6A1 mRNA expression was significantly up-regulated in individuals with rs17551710/rs7671-GG/GG and rs1053312/rs13051496-AA+AG/CC genotypes compared with other genotypes. CONCLUSION: SNPs in the COL6A1 promoter and exonic regions are associated with TOLF in the Chinese Han population, and lead to up-regulated COL6A1 expression. We confirmed COL6A1 as a TOLF susceptibility gene that may be involved in TOLF pathology.

Degenerative lumbar scoliosis patients with proximal junctional kyphosis have lower muscularity, fatty degeneration at the lumbar area.

PURPOSE: To assess the lumbar muscle conditions on the incidence of proximal junctional kyphosis (PJK) after long-level correction and instrumentation surgery for degenerative lumbar scoliosis (DLS) patients with a minimum 2-year follow-up. METHODS: Eighty-four DLS patients undergoing long instrumented fusion surgery (≥ 5 vertebrae) were retrospectively studied. According to the occurrence of PJK at the final follow-up, patients were divided into the PJK group and the Non-PJK group. Patient characteristics, surgical variables and radiographic parameters were analyzed statistically. The lumbar muscularity (cross-sectional area of muscle-disc ratio × 100) and fatty degeneration (signal intensity of muscle-subcutaneous fat ratio × 100) were evaluated on magnetic resonance imaging . RESULTS: The prevalence of PJK was 20.24%. Gender, age at surgery, body mass index, uppermost instrumented vertebrae level, fusions extending to the sacrum, and levels fused were not significantly different between the groups. Lower bone mineral density, smaller functional cross-sectional area (FCSA) of paraspinal extensor muscles (PSE), higher lean muscle-fat index and total muscle-fat index of PSE, greater preoperative thoracolumbar kyphosis (TLK), smaller preoperative sacral slope (SS), larger preoperative sagittal vertical axis were identified in PJK group. Logistic regression analysis showed that osteoporosis, preoperative TLK > 15°, SS > 24°, FCSA of PSE > 138.75, and total muscle-fat index of PSE > 4.08 were independently associated with PJK. The final follow-up VAS score for back pain was higher, and SRS-22 subcategories of pain, function, self-image, and total score were significantly lower in the PJK group. CONCLUSION: Osteoporosis, lower lumbar muscularity and higher fatty degeneration, preoperative greater TLK and smaller SS were found to be strongly associated with the presence of PJK in DLS.

Radiographic and clinical features of thoracic disk disease associated with myelopathy: a retrospective analysis of 257 cases.

PURPOSE: To analyze the clinical and radiographic characteristics of thoracic disk disease associated with myelopathy (TDM). METHODS: This is a retrospective clinical review of prospectively collected imaging data based at a single institute. Based on preoperative CT and MRI, we classified TDM as thoracic disk herniation (TDH), THD with ossification (THDO), TDH with posterior bony avulsions of the vertebrae (TDH with PBA), TDH with posterior vertebral osteophytes (TDH with PVO), giant thoracic osteophyte and calcific discitis with herniation (CDH). Patient characteristics and radiographic data were compared between different types of TDM. RESULTS: Among the 257 patients included, 12.06% of patients presented with symptoms after traumatic events. The most frequent complaint at onset and preoperative was back pain (29.2%) and subjective lower limb weakness (75.5%), respectively. All TDH with PBA is distributed at the lower thoracic segments, while CDH predominantly in the middle and lower thoracic segments. TDH with PBA was more frequent in men than TDH and CDH. Compared with TDH, TDHO, and TDH with PVO, TDH with PBA was younger in surgery age, and TDH and CDH had lower preoperative JOA scores than TDH with PBA. CDH had a larger ventral occupying ratio than TDH, TDHO, and TDH with PBA. CONCLUSIONS: The onset of TDM was generally insidious but may be triggered acutely by apparently trivial events. With a low prevalence, TDM varied clinical symptoms. Different types of TDM had various clinical features, which might indicate different pathological mechanisms.

Risk factors associated with post-operative neurological deterioration in patients with thoracic disc disorders with myelopathy.

PURPOSE: Post-operative neurological deterioration (ND) is a severe complication. However, limited literature exists on the ND in thoracic disc disorders with myelopathy (TDM). This study describes the risk factors of neurological deterioration in TDM with instrumentation and fusion. METHODS: A single-centre review of TDM with instrumentation and fusion during 2006-2019 was performed. Post-operative neurological deterioration was defined as the deterioration of pre-existing neurological function or the appearance of new neurological symptoms. Patients were then grouped into two groups depending on neurological deterioration (ND group) or not (non-ND group). Demographics, radiographic parameters, and surgical characteristics were compared between the two groups. RESULTS: A total of 257 cases were included, and neurological deterioration occurred in 16 (6.23%) cases. Multivariate analysis revealed spinal canal occupancy ratio > 75%, U-shaped compressed spinal cord in axial MRI, calcified herniated disc, anterior approach, and intra-operative blood loss > 1500 mL were associated with ND. Ten patients (62.5%) had complete neurological recovery within six months, and four patients (25%) had progressive neurological function improvement and equal or better than pre-operation within nine months. CONCLUSIONS: The rate of neurological deterioration is 6.23%, and a higher spinal canal occupancy ratio, U-shaped compressed spinal cord, calcified herniated disc, anterior approach, and massive intra-operative blood loss were associated with neurological deterioration. Long-term outcomes of neurological deterioration are favourable, and 62.5% of patients experienced complete neurological recovery within six months. Patients with TMD who undergo surgery should be properly informed of the potential risks of neurological deterioration, despite its usually transient nature in most patients.

Pseudomeningocele-a rare complication following thoracic spinal decompression surgery: clinical features, treatment guidelines, technical notes, and evaluation of results.

PURPOSE: Pseudomeningocele (PMC) is a rare complication following thoracic spinal decompression surgery. The aim of this study is to assess the clinical features and treatment of PMC and provide the technical notes with revision surgery. METHODS: Between January 2010 and December 2019, patients who developed PMC after posterior thoracic surgery were enrolled. An additional 25 patients who suffered cerebrospinal fluid leakage (CSFL) but did not develop PMC in the same period were randomly selected. General data, intra-operative factors, CSFL position, cost, modified Japanese Orthopaedic Association (mJOA) scores, patient satisfaction, and clinical features were recorded and compared between the two groups. RESULTS: Eighteen patients were diagnosed with PMC after thoracic spinal surgery. The average length, width, and depth were 16.25 ± 5.73 cm, 6.96 ± 3.61 cm and 4.39 ± 2.2 cm, respectively. The most common symptom was neurological deficits following incision problems and headache. Compared with the control group, the PMC group showed a longer duration of initial surgery, greater estimated blood loss, an increased rate of CSFL on the ventral side, reduced mJOA scores, and lower patient satisfaction at the final follow-up. CONCLUSION: PMC is a rare complication of thoracic surgery with an incidence of 1.12%. PMC typically occurs at the upper and lower thoracic spine, resulting in increased health care costs, poorer neurological recovery, and a lower rate of patient satisfaction. The management of PMC should be individualized depending on diagnosis time and symptoms.