Acute changes in hippocampal metabolism after anesthesia and surgery: Implications for perioperative neurocognitive disorder.

BACKGROUND: The risk of developing dementia is higher in individuals who suffer from perioperative neurocognitive disorder (PND), including postoperative cognitive dysfunction (POCD) and delirium. Recent studies have indicated correlations between anesthesia, surgery and PND. Acute metabolic changes induced by anesthesia and surgery may be related to cognitive impairments. Despite a paucity of research on acute metabolic changes in the hippocampus during surgery, there are conflicting about specific metabolites. METHODS: We developed a mouse model of cognitive impairment induced by isoflurane anesthesia and unilateral nephrectomy. Cognition was evaluated by Y maze and fear conditioning test (FCT). The hippocampus was harvested after the surgery. LC-MS (liquid chromatography-mass spectrometry) was performed. The differential metabolites involved in lipid, amino acid, nucleotide, carbohydrate metabolism were analyzed. RESULTS: Anesthesia and surgery exposure induced cognition decline. A total of 49 metabolites were significantly up-regulated and 122 down-regulated. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway of the metabolites identified purine, glutathione, nicotinate and nicotinamide metabolism. Metabolites involved in lipid, amino acid, nucleotide, carbohydrate metabolism were identified including nicotinamide adenine dinucleotide (NAD), 1-Methylnicotinamide, propionic acid, histidine, adenosine, and guanosine cyclic monophosphate. Some metabolites exhibited a consistent change trend in the hippocampus of aging mice. CONCLUSIONS: The study indicates that anesthesia and surgery can induce acute alterations in hippocampal metabolomics, including metabolites involved in lipid, amino acid, nucleotide, and carbohydrate metabolism. These metabolites may play a role in modulating PND through the regulation of neuroinflammation, oxidative stress, blood-brain barrier (BBB) permeability.

Can pelvic incidence affect changes in sagittal spino-pelvic parameters between standing and sitting positions in individuals with lumbar degenerative disease?

OBJECTIVE: The aim of this study was to explore the correlation between PI and standing-to-sitting changes of the sagittal alignment in patients with lumbar degenerative diseases, and investigate the differences in posture changes among Roussouly types. METHODS: A total of 209 patients with lumbar degenerative disease were retrospectively included in this study. All the patients received lateral full body imaging in both standing and sitting positions. Sagittal parameters including SVA, OD-HA, PT, PI, PT/PI, SS, LL, TK, Upper LL (L1-L4) and Lower LL (L4-S1) were measured in both standing and sitting position, and the parameters were compared between two positions. The correlations between PI and lumbo-pelvic changes were analyzed. The postural changes were compared among different Roussouly types. RESULTS: From standing to sitting, all the parameters except PI significantly changed, including SVA, OD-HA, PT, PT/PI, SS, LL, TK, Upper LL and Lower LL. The contribution of lower LL was greater to global LL than upper LL. PI had a significant correlation with ΔPT, ΔSS, ΔLL, ΔUpper LL and ΔLower LL. From standing to sitting, type 4 patients had the most pronounced ΔPT, ΔSS and ΔLL, and ΔLower LL of types 3 and 4 were greater than that of types 1 and 2. CONCLUSIONS: In patients with degenerative disease, PI plays an important role in determining the extent of lumbo-pelvic changes from standing to sitting. Among different Roussouly types, type 4 patients have the most pronounced changes of PT, SS and LL, suggesting the relatively greater flexibility of pelvis and lumbar spine.

The Role of Spinal Cord Compression in Predicting Intraoperative Neurophysiological Monitoring Events in Patients With Kyphotic Deformity: A Magnetic Resonance Imaging-Based Study.

OBJECTIVE: To establish a novel classification system for predicting the risk of intraoperative neurophysiological monitoring (IONM) events in surgically-treated patients with kyphotic deformity. METHODS: Patients with kyphotic deformity who underwent surgical correction of cervicothoracic, thoracic, or thoracolumbar kyphosis in our center from July 2005 to December 2020 were recruited. We proposed a classification system to describe the morphology of the spinal cord on T2-weighted sagittal magnetic resonance imaging: type A, circular/symmetric cord with visible cerebrospinal fluid (CSF) between the cord and vertebral body; type B, circular/oval/symmetric cord with no visible CSF between the cord and vertebral body; type C, spinal cord that is fattened/deformed by the vertebral body, with no visible CSF between the cord and vertebral body. Furthermore, based on type C, the spinal cord compression ratio (CR) < 50% was defined as the subtype C-, while the spinal cord CR ≥ 50% was defined as the subtype C+. IONM event was documented, and a comparative analysis was made to evaluate the prevalence of IONM events among patients with diverse spinal cord types. RESULTS: A total of 294 patients were reviewed, including 73 in type A; 153 in type B; 53 in subtype C- and 15 in subtype C+. Lower extremity transcranial motor-evoked potentials and/or somatosensory evoked potentials were lost intraoperatively in 41 cases (13.9%), among which 4 patients with type C showed no return of spinal cord monitoring data. The 14 subtype C+ patients (93.3%) had IONM events. Univariate logistic regression analysis showed that patients with a type C spinal cord (subtype C-: odds ratio [OR], 10.390; 95% confidence interval [CI], 2.215-48.735; p = 0.003; subtype C+, OR, 497.000; 95% CI, 42.126- 5,863.611; p < 0.001) are at significantly higher risk of a positive IONM event during deformity correction compared to those with a type A. In further multiple logistic regression analysis, the spinal cord classification (OR, 5.371; 95% CI, 2.966-9.727; p < 0.001) was confirmed as an independent risk factor for IONM events. CONCLUSION: We presented a new spinal cord classification system based on the relative position of the spinal cord and vertebrae to predict the risk of IONM events in patients with kyphotic deformity. In patients with type C spinal cord, especially those in C+ cases, it is essential to be aware of potential IONM events, and adopt standard operating procedures to facilitate neurological recovery.

Presence of compensatory curve predicts postoperative curve progression in congenital scoliosis after thoracolumbar hemivertebra resection and short fusion.

PURPOSE: To investigate the impact of preoperative compensatory curve on the postoperative curve progression in congenital scoliosis (CS) patients following thoracolumbar hemivertebra (HV) resection and short fusion. METHODS: This study retrospectively reviewed a consecutive cohort of patients with CS who underwent thoracolumbar HV resection and short fusion with a minimum of 2 years follow-up. According to the preoperative curve pattern, patients were divided into compensatory curve group non-compensatory curve group. Based on the postoperative coronal curve evolution, patients were further divided into the progressed group (Group P, with curve decompensation ≥ 20°) and the non-progressed group (Group NP, characterized by well-compensated curves). RESULTS: A total of 127 patients were included in this study, with 31 patients in the compensatory curve group and 96 patients in the non-compensatory curve group. The incidence of postoperative coronal curve progression was significantly higher in the compensatory curve group than that in non-compensatory curve group (35.5% vs. 13.5%, p = 0.007). In the compensatory curve group, patients who experienced postoperative curve progression showed fewer fusion segments (p = 0.001), greater preoperative UIV translation (p = 0.006), greater preoperative LIV tilt (p = 0.017), and larger postoperative UIV tilt (p < 0.001) compared with patients in group NP. Multiple logistic regression demonstrated that the shorter fusion segments and greater postoperative UIV tilt were two independent risk factors for postoperative curve progression. CONCLUSION: The presence of the compensatory curve was associated with a higher incidence of postoperative curve progression in patients with CS who underwent thoracolumbar HV resection and short fusion. Shorter fusion segments and greater postoperative UIV tilt were found to be the risk factors for postoperative curve progression.

The hyaluronic acid-gelatin hierarchical hydrogel for osteoporotic bone defect repairment.

Osteoporotic bone defects are serious medical problems due to their sparse bone structure, difficulty in restoration and reconstruction, and high recurrence rates, which also result in heavy economic and social burdens. Herein, we developed a hierarchical hydrogel composed of alendronate sodium (AS)/Mg2+-loaded inverse opal methylpropenylated gelatin (GelMA) hydrogel microspheres (IOHM-AS-Mgs) within methylpropenylated poly(hyaluronic acid) (HAMA) for osteoporotic bone defect treatment. The IOHM-AS-Mgs displayed good cytocompatibility and cell adhesion and strongly stimulated osteogenesis at the transcriptomic and protein levels. When this treatment was applied to the osteoporotic bone defect area, HAMA was used to fix the microspheres. The results of the microcomputed tomography (micro-CT) and histological analyses indicated that the hierarchical hydrogel had the best therapeutic effect. Therefore, this hydrogel is a new candidate for osteoporotic bone defect treatment.

Nuclear receptor Rev-erbα alleviates intervertebral disc degeneration by recruiting NCoR-HDAC3 co-repressor and inhibiting NLRP3 inflammasome.

Intervertebral discs (IVDs) are rhythmic tissues that experience daily low-load recovery. Notably, aging and abnormal mechanical stress predispose IVDs to degeneration due to dysrhythmia-induced disordered metabolism. Meanwhile, Rev-erbα acts as a transcriptional repressor in maintaining biorhythms and homeostasis; however, its function in IVD homeostasis and degeneration remains unclear. This study assessed the relationship between low Rev-erbα expression levels and IVD degeneration. Rev-erbα deficiency accelerated needle puncture or aging-induced IVD degeneration, characterized by increased extracellular matrix (ECM) catabolism and nucleus pulposus (NP) cell apoptosis. Mechanistically, Rev-erbα knockdown in NP cells aggravated rhIL1ß-induced NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome activation, exacerbating the imbalanced ECM and NP cell apoptosis. Meanwhile, blocking NLRP3 inflammasome activation mitigated Rev-erbα deficiency and needle puncture-induced IVD degeneration. Particularly, Rev-erbα mediated the transcriptional repression of the NLRP3 inflammasome via the ligand heme-binding of nuclear receptor co-repressor (NCoR) and histone deacetylase 3 (HDAC3) complex. Thus, the increased expression of Rev-erbα in NP cells following short-term rhIL1ß treatment failed to inhibit NLRP3 transcription in vitro owing to heme depletion. Pharmacological activation of Rev-erbα in vivo and in vitro alleviated IVD degeneration by altering the NLRP3 inflammasome. Taken together, targeting Rev-erbα may be a potential therapeutic strategy for alleviating IVD degeneration and its related diseases.

Prediction Model for Lumbar Curve Correction after Selective Thoracic Fusion in Lenke 1 and 2 Adolescent Idiopathic Scoliosis.

STUDY DESIGN: A retrospective study. OBJECTIVE: To identify independent risk factors and construct a prediction model for lumbar curve correction (LCC) after selective thoracic fusion (STF) in patients with Lenke 1 and 2 adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: STF has been widely applied in Lenke 1 and 2 AIS patients. However, LCC after STF is still controversial. METHODS: 128 patients undergoing STF with at least 2 years follow-up were included. Cases were divided into high-LCC group and low-LCC group according to a rounded-up median of 65%. 49 variables were taken into account. Logistic regression was applied to identify independent predictive factors. Prediction model was established by backward stepwise regression, and its evaluation was implemented on R. RESULTS: Five parameters showed independent predictive value for low LCC: Right shoulder higher before surgery [right shoulder higher vs. balanced: odds ratio (OR)=0.244, P=0.014], postoperative Cobb angle of lumbar curve (LC) (OR=1.415, P=0.001, cut-off value=11°), lowest instrumented vertebra (LIV) distal to end vertebra (no vs. yes: OR=4.587, P=0.013), postoperative LIV tilt (OR=0.686, P=0.010, cut-off value=6.85°) and postoperative LIV+1 tilt (OR=1.522, P=0.005, cut-off value=6.25°). The prediction model included six variables: lumbar modifier, preoperative shoulder balance, postoperative Cobb angle of LC, LIV position, postoperative LIV tilt and postoperative LIV+1 tilt. Model evaluation demonstrated satisfactory capability and stability [area under curve=0.890, 10-fold cross-validation accuracy=0.782]. CONCLUSION: Preoperative shoulder balance, Cobb angle of LC, LIV position, postoperative LIV and LIV+1 tilt could be used to prognosticate LCC after STF. A model with solid prediction ability was established, which could further our understanding of LCC and assist in making clinical decisions.

Regulating the activity of GABAergic neurons in the ventral pallidum alters the general anesthesia effect of propofol.

The full mechanism of action of propofol, a commonly administered intravenous anesthetic drug in clinical practice, remains elusive. The focus of this study was the role of GABAergic neurons which are the main neuron group in the ventral pallidum (VP) closely associated with anesthetic effects in propofol anesthesia. The activity of VP GABAergic neurons following propofol anesthesia in Vgat-Cre mice was observed via detecting c-Fos immunoreactivity by immunofluorescence and western blotting. Subsequently, chemogenetic techniques were employed in Vgat-Cre mice to regulate the activity of VP GABAergic neurons. The role of VP GABAergic neurons in generating the effects of general anesthesia induced by intravenous propofol was further explored through behavioral tests of the righting reflex. The results revealed that c-Fos expression in VP GABAergic neurons in Vgat-Cre mice dramatically decreased after propofol injection. Further studies demonstrated that chemogenetic activation of VP GABAergic neurons during propofol anesthesia shortened the duration of anesthesia and promoted wakefulness. Conversely, the inhibition of VP GABAergic neurons extended the duration of anesthesia and facilitated the effects of anesthesia. The results obtained in this study suggested that regulating the activity of GABAergic neurons in the ventral pallidum altered the effect of propofol on general anesthesia.

Opioid Use Prior to Adult Spine Deformity Correction Surgery is Associated With Worse Pre- and Postoperative Back Pain and Prolonged Opioid Demands.

STUDY DESIGN: Prospective multicenter database post-hoc analysis. OBJECTIVES: Opioids are frequently prescribed for painful spinal conditions to provide pain relief and to allow for functional improvement, both before and after spine surgery. Amidst a current opioid epidemic, it is important for providers to understand the impact of opioid use and its relationship with patient-reported outcomes. The purpose of this study was to evaluate pre-/postoperative opioid consumption surrounding ASD and assess patient-reported pain outcomes in older patients undergoing surgery for spinal deformity. METHODS: Patients ≥60 years of age from 12 international centers undergoing spinal fusion of at least 5 levels and a minimum 2-year follow-up were included. Patient-reported outcome scores were collected using the Numeric Rating Scale for back and leg pain (NRS-B; NRS-L) at baseline and at 2 years following surgery. Opioid use, defined based on a specific question on case report forms and question 11 from the SRS-22r questionnaire, was assessed at baseline and at 2-year follow-up. RESULT: Of the 219 patients who met inclusion criteria, 179 (81.7%) had 2-year data on opioid use. The percentages of patients reporting opioid use at baseline (n = 75, 34.2%) and 2 years after surgery (n = 55, 30.7%) were similar (P = .23). However, at last follow-up 39% of baseline opioid users (Opi) were no longer taking opioids, while 14% of initial non-users (No-Opi) reported opioid use. Regional pre- and postoperative opioid use was 5.8% and 7.7% in the Asian population, 58.3% and 53.1% in the European, and 50.5% and 40.2% in North American patients, respectively. Baseline opioid users reported more preoperative back pain than the No-Opi group (7.0 vs 5.7, P = .001), while NRS-Leg pain scores were comparable (4.8 vs 4, P = .159). Similarly, at last follow-up, patients in the Opi group had greater NRS-B scores than Non-Opi patients (3.2 vs 2.3, P = .012), but no differences in NRS-Leg pain scores (2.2 vs 2.4, P = .632) were observed. CONCLUSIONS: In this study, almost one-third of surgical ASD patients were consuming opioids both pre- and postoperatively world-wide. There were marked international variations, with patients from Asia having a much lower usage rate, suggesting a cultural influence. Despite both opioid users and nonusers benefitting from surgery, preoperative opioid use was strongly associated with significantly more back pain at baseline that persisted at 2-year follow up, as well as persistent postoperative opioid needs.

Deep Learning-Based Prediction Model for the Cobb Angle in Adolescent Idiopathic Scoliosis Patients.

Scoliosis, characterized by spine deformity, is most common in adolescent idiopathic scoliosis (AIS). Manual Cobb angle measurement limitations underscore the need for automated tools. This study employed a vertebral landmark extraction method and Feedforward Neural Network (FNN) to predict scoliosis progression in 79 AIS patients. The novel intervertebral angles matrix format showcased results. The mean absolute error for the intervertebral angle progression was 1.5 degrees, while the Pearson correlation of the predicted Cobb angles was 0.86. The accuracy in classifying Cobb angles (<15°, 15-25°, 25-35°, 35-45°, >45°) was 0.85, with 0.65 sensitivity and 0.91 specificity. The FNN demonstrated superior accuracy, sensitivity, and specificity, aiding in tailored treatments for potential scoliosis progression. Addressing FNNs' over-fitting issue through strategies like "dropout" or regularization could further enhance their performance. This study presents a promising step towards automated scoliosis diagnosis and prognosis.

Establishing mainstream partial nitrification in the membrane aerated biofilm reactor by limiting the oxygen concentration in the biofilm.

The proliferation of nitrite oxidizing bacteria (NOB) still remains as a major challenge for nitrogen removal in mainstream wastewater treatment process based on partial nitrification (PN). This study investigated different operational conditions to establish mainstream PN for the fast start-up of membrane aerated biofilm reactor (MABR) systems. Different oxygen controlling strategies were adopted by employing different influent NH4+-N loads and oxygen supply strategies to inhibit NOB. We indicated the essential for NOB suppression was to reduce the oxygen concentration of the inner biofilm and the thickness of aerobic biofilm. A higher NH4+-N load (7.4 g-N/(m2·d)) induced higher oxygen utilization rate (14.4 g-O2/(m2·d)) and steeper gradient of oxygen concentration, which reduced the thickness of aerobic biofilm. Employing closed-end oxygen supply mode exhibited the minimum concentration of oxygen to realize PN, which was over 46% reduction of the normal open-end oxygen mode. Under the conditions of high NH4+-N load and closed-end oxygen supply mode, the microbial community exhibited a comparative advantage of ammonium oxidizing bacteria over NOB in the aerobic biofilm, with a relative abundance of Nitrosomonas of 30-40% and no detection of Nitrospira. The optimal fast start-up strategy was proposed with open-end aeration mode in the first 10 days and closed-end mode subsequently under high NH4+-N load. The results revealed the mechanism of NOB inhibition on the biofilm and provided strategies for a quick start-up and stable mainstream PN simultaneously, which poses great significance for the future application of MABR.

Coronal deformity in ankylosing spondylitis with concomitant thoracolumbar kyphosis: patterns, manifestations and surgical strategies.

PURPOSE: To evaluate different patterns of coronal deformity secondary to ankylosing spondylitis (AS), to propose relevant treatment strategies, and to assess efficacy of asymmetrical pedicle subtraction osteotomy (APSO). METHODS: Coronal deformity was defined as coronal Cobb angle over 20º or coronal balance distance (CBD) more than 3 cm. 65 consecutive AS patients with concomitant coronal and sagittal deformity who underwent PSO were included. The average follow-up time was 40.4 months. Radiographic evaluation included coronal Cobb angle and CBD. Furthermore, sagittal parameters were used to assess magnitude and maintenance of kyphosis correction. RESULTS: Based on curve characteristics, coronal deformity caused by AS included four different radiologic patterns: Pattern I: lumbar scoliosis; Pattern II: C-shaped thoracolumbar curve; Pattern III: trunk shift without major curve; Pattern IV: proximal thoracic scoliosis. APSO was performed for patients in Pattern I to III while conventional PSO was applied for patients in Pattern IV. Significant improvement in all the sagittal parameters were noted in 65 patients without obvious correction loss at the last follow-up. Besides, significant and sustained correction of coronal mal-alignment was identified in 59 APSO-treated patients. Rod fracture occurred in four cases and revision surgery was performed for one case. CONCLUSION: According to radiologic manifestations, coronal deformity caused by AS could be categorized into four patterns. APSO proved to be a feasible and effective procedure for correction of Pattern I to III patients. Coronal deformity pattern, apex location, sagittal profile of lumbar spine and preoperative hip function should be considered for osteotomy level selection in APSO.

Impaired synaptic plasticity and decreased glutamatergic neuron excitability induced by SIRT1/BDNF downregulation in the hippocampal CA1 region are involved in postoperative cognitive dysfunction.

BACKGROUND: Postoperative cognitive dysfunction (POCD) is a common complication after anesthesia/surgery, especially among elderly patients, and poses a significant threat to their postoperative quality of life and overall well-being. While it is widely accepted that elderly patients may experience POCD following anesthesia/surgery, the exact mechanism behind this phenomenon remains unclear. Several studies have indicated that the interaction between silent mating type information regulation 2 homologue 1 (SIRT1) and brain-derived neurotrophic factor (BDNF) is crucial in controlling cognitive function and is strongly linked to neurodegenerative disorders. Hence, this research aims to explore how SIRT1/BDNF impacts cognitive decline caused by anesthesia/surgery in aged mice. METHODS: Open field test (OFT) was used to determine whether anesthesia/surgery affected the motor ability of mice, while the postoperative cognitive function of 18 months old mice was evaluated with Novel object recognition test (NORT), Object location test (OLT) and Fear condition test (FC). The expressions of SIRT1 and other molecules were analyzed by western blot and immunofluorescence staining. The hippocampal synaptic plasticity was detected by Golgi staining and Long-term potentiation (LTP). The effects of SIRT1 and BDNF overexpression as well as chemogenetic activation of glutamatergic neurons in hippocampal CA1 region of 18 months old vesicular glutamate transporter 1 (VGLUT1) mice on POCD were further investigated. RESULTS: The research results revealed that older mice exhibited cognitive impairment following intramedullary fixation of tibial fracture. Additionally, a notable decrease in the expression of SIRT1/BDNF and neuronal excitability in hippocampal CA1 glutamatergic neurons was observed. By increasing levels of SIRT1/BDNF or enhancing glutamatergic neuron excitability in the CA1 region, it was possible to effectively mitigate synaptic plasticity impairment and ameliorate postoperative cognitive dysfunction. CONCLUSIONS: The decline in SIRT1/BDNF levels leading to changes in synaptic plasticity and neuronal excitability in older mice could be a significant factor contributing to cognitive impairment after anesthesia/surgery.

Dynamic microphysiological system chip platform for high-throughput, customizable, and multi-dimensional drug screening.

Spheroids and organoids have attracted significant attention as innovative models for disease modeling and drug screening. By employing diverse types of spheroids or organoids, it is feasible to establish microphysiological systems that enhance the precision of disease modeling and offer more dependable and comprehensive drug screening. High-throughput microphysiological systems that support optional, parallel testing of multiple drugs have promising applications in personalized medical treatment and drug research. However, establishing such a system is highly challenging and requires a multidisciplinary approach. This study introduces a dynamic Microphysiological System Chip Platform (MSCP) with multiple functional microstructures that encompass the mentioned advantages. We developed a high-throughput lung cancer spheroids model and an intestine-liver-heart-lung cancer microphysiological system for conducting parallel testing on four anti-lung cancer drugs, demonstrating the feasibility of the MSCP. This microphysiological system combines microscale and macroscale biomimetics to enable a comprehensive assessment of drug efficacy and side effects. Moreover, the microphysiological system enables evaluation of the real pharmacological effect of drug molecules reaching the target lesion after absorption by normal organs through fluid-based physiological communication. The MSCP could serves as a valuable platform for microphysiological system research, making significant contributions to disease modeling, drug development, and personalized medical treatment.

Lumbar Apex Position as an Independent Risk Factor for Adjacent Segment Diseases in Patients Undergoing Short-level Transforaminal Lumbar Interbody Fusion.

STUDY DESIGN: Retrospective study. OBJECTIVE: To investigate whether lumbar apex position had an impact on the development of adjacent segment disease (ASD) following transforaminal lumbar interbody fusion (TLIF). SUMMARY OF BACKGROUND DATA: Previous studies have demonstrated that solely concentrating on lumbar lordosis value is not suitable and neglecting the significance of lumbar apex can lead to mechanical complications. However, the relationship between lumbar apex and ASD is still not well understood. METHODS: In this retrospective study, 234 consecutive patients who underwent L3-5 or L4-5 TLIF for degenerative diseases were reviewed. The study evaluated the associations between sagittal parameters and pelvic incidence (PI). Patients were labeled "matched" when lumbar apex position aligned with the theoretical target, and "mismatched" when it did not. Multivariate analysis was applied to find the independent risk factors of ASD. Additionally, a focused sub-analysis was performed based on the lumbar apex position (ideal match, cranial from ideal, and caudal from ideal). RESULTS: After an average follow-up period of 70.6 months, 68 cases were identified as having ASD. Postoperatively, 64.7% (44 out of 68) of the patients with ASD exhibited a mismatched lumbar apex, compared to 41% (68 out of 166) of those without ASD (p < 0.001). PI correlated significantly with proximal lordosis (PL) and lordosis distribution index (LDI), but not with distal lordosis (DL). Multivariate analysis identified age, L3-5 fusion, postoperative DL, and postoperative mismatched lumbar apex as independent risk factors of ASD. Upon the sub-analysis, it was discovered that there were unique compensatory strategies in the cranial and caudal groups, with notable variations in postoperative DL, PL, and LDI among three groups (all p value<0.05). CONCLUSION: Lumbar apex position significantly influenced the risk of ASD. To restore the lumbar apex to its ideal position, a proper value and distribution of DL should be attained.

Sagittal Imbalance in Degenerative Kyphosis: Prevalence and Implication on Postoperative Mechanical Failure.

BACKGROUND AND OBJECTIVES: To explore the patterns of sagittal imbalance in patients with lumbar or thoracolumbar degenerative kyphosis (DK) and determine its implication for the risk of mechanical complication (MC) after corrective surgery. METHODS: A total of 137 patients with DK who underwent corrective surgery were reviewed. The patients were divided into L group (with a kyphotic apex at L2 and below) and TL group (with kyphotic apex at L1 and above). Then, sacral slope (SS) (defined as S1 if SS > 0 in TL, or SS > 10 in L group) and sagittal vertical axis ≥ 5 cm (defined as +) were used as modifier sagittal balance. The Scoliosis Research Society (SRS)-22 questionnaire scores were analyzed, and the risk of mechanical failure was compared across groups. RESULTS: The distribution of subgroups was 38 (27.7%) in TLS1(-) group, 36 (26.3%) in TLS1(+) group, 16 (11.7%) in TLS0(-) group, and 5 (3.6%) in TLS0(+) group. For L group, the figure was 5 (3.6%) in LS1(-), 22 (16.1%) in LS1(+), 7 (5.2%) in LS0(-), and 8 (5.8%) in LS0(+). Patients in L group had significantly higher regional kyphosis, lower lumbar lordosis, and higher sagittal vertical axis, indicating a higher risk of global decompensation. The SRS function scores and pain scores were also lower in the L group compared with the TL group. At a minimum of 2 years of follow-up, χ2 test showed that the incidence of TLS0 (+), LS0 (-), and LS0 (+) had significantly higher rates of MC (>40%). In both TL and L groups, patients with MC were found to have significantly lower bone mineral density than those without. CONCLUSION: The findings decipher the distinct patterns of sagittal imbalance in severe DK patients with kyphotic apex at thoracolumbar or lumbar spine. Patients with kyphotic apex apex at L2 or below, low SS, and global imbalance showed the highest risk of postoperative mechanical failure.

Seismic noise in South China Sea: High-quality time-frequency analysis from 0.01 to 125 Hz.

An efficient and precise time-frequency analysis method for real-time ocean bottom seismometer (RTOBS) data in the South China Sea (SCS) is presented. Overcoming the limitations of conventional methods, the method involves temporal segmentation, unique frequency octaves, and Fourier transforms to generate power spectral density (PSD) and probability density function profiles. The method demonstrates superior precision, computational efficiency, and full-bandwidth (0 to Nyquist) capability compared to traditional techniques, as validated through theoretical and empirical evaluations. Applied to SCS RTOBS data, it unveils temporal PSD variations, shedding light on underwater noise sources like earthquakes, offshore blasting, ship-induced disturbances, and tidal effects. Establishing background noise levels in the SCS supports noise source categorization and ocean environment monitoring. Furthermore, comparing onshore and offshore seismic stations advances interdisciplinary research, fostering a comprehensive understanding of acoustics and seismology in the region.

Posterior Corrective Surgery for Type II Congenital Kyphosis: SRS-Schwab Grade 4 Osteotomy or Vertebral Column Resection?

OBJECTIVE: Surgical decision-making for congenital kyphosis (CK) with failure of anterior segmentation (type II) has been contradictory regarding the trade-off between the pursuit of correction rate and the inherent risk of the osteotomy procedure. This study was designed to compare the clinical and radiographic measurement in type II CK underwent SRS-Schwab Grade 4 osteotomy and vertebral column resection (VCR), the most-adapted osteotomy techniques for CK, and to propose the strategy to select between the two procedures. METHODS: This retrospective observational comparative study evaluated surgical outcomes in type II CK patients underwent VCR or SRS-Schwab Grade 4 osteotomy at our institution between January 2015 and January 2020. Patients operated with VCR and SRS-Schwab Grade 4 osteotomy were allocated to Group 1 and Group 2 respectively. Radiographic parameters and SRS-22 quality of life metrics were assessed at pre-operation, post-operation, and during follow-up visits for both groups, allowing for a comprehensive comparison of surgical outcomes. RESULTS: Thirty-one patients (19 patients in Group 1 and 12 patients in Group 2) aged 16.3 ± 10.4 years were recruited. Correction of segmental kyphosis was similar between groups (51.1 ± 17.6° in Group 1 and 48.4 ± 19.8° in Group 2, p = 0.694). Group 1 had significantly longer operation time (365.9 ± 81.2 vs 221.4 ± 78.9, p < 0.001) and more estimated blood loss (975.2 ± 275.8 ml vs 725.9 ± 204.3 mL, p = 0.011). Alert event of intraoperative sensory and motor evoked potential (SEP and MEP) monitoring was observed in 1 patient of Group 2. Both groups had 1 transient post operative neurological deficit respectively. CONCLUSION: SRS-Schwab Grade 4 osteotomy was suitable for kyphotic mass when its apex is the upper unsegmented vertebrae or the neighboring disc, or when the apical vertebrae with an anterior/posterior (A/P) height ratio of vertebral body higher than 1/3. VCR is suitable when the apex is located within the unsegmented mass with its A/P height ratio lower than 1/3. Proper selection of VCR and SRS-Schwab Grade 4 osteotomy according to our strategy, could provide satisfying radiographic and clinical outcomes in type II CK patients during a minimum of 2 years follow-up. Patients undergoing VCR procedure might have longer operation time, more blood loss and higher incidence of peri- and post-operative complications.

Quantifying Methane Influx from Sewer into Wastewater Treatment Processes.

Wastewater treatment contributes substantially to methane (CH4) emissions, yet monitoring and tracing face challenges because the treatment processes are often treated as a "black box". Particularly, despite growing interest, the amount of CH4 carryover and influx from the sewer and its impacts on overall emissions remain unclear. This study quantified CH4 emissions from six wastewater treatment plants (WWTPs) across China, utilizing existing multizonal odor control systems, with a focus on Beijing and Guiyang WWTPs. In the Beijing WWTP, almost 90% of CH4 emissions from the wastewater treatment process were conveyed through sewer pipes, affecting emissions even in the aerobic zone of biological treatment. In the Guiyang WWTP, where most CH4 from the sewer was released at the inlet well, a 24 h online monitoring revealed CH4 fluctuations linked to neighborhood water consumption and a strong correlation to influent COD inputs. CH4 emission factors monitored in six WWTPs range from 1.5 to 13.4 gCH4/kgCODrem, higher than those observed in previous studies using A2O technology. This underscores the importance of considering CH4 influx from sewer systems to avoid underestimation. The odor control system in WWTPs demonstrates its potential as a cost-effective approach for tracing, monitoring, and mitigating CH4.