ObjectiveWhether bacterial hypotoxic infection in the intervertebral disc is the cause of disc degenerative disease (DDD) is controversial. The mNGS technique can provide valuable insights by obtaining more comprehensive evidence of the presence of bacteria in the intervertebral disc. This study was designed to analyze the characteristics of intervertebral microbiome structure in patients with lumbar disc degenerative disease and its correlation with clinical indicators.MethodsA total of 104 patients with lumbar disc degenerative diseases were included in this study. The surgically removed lumbar intervertebral disc tissues were collected for clinical culture and metagenomic second-generation sequencing (mNGS), and the consistency of the two microbial detection methods was compared.According to the collected clinical information, patients were grouped according to the modified Pfirrmann grading, Modic typing and age, and the differences of microbial communities detected by mNGS among different groups were compared, including α diversity analysis, β diversity analysis, species abundance difference analysis, etc. Spearman correlation between clinical features and generic relative abundance was calculated.ResultsThe effective culture results of 104 intervertebral disc tissue samples were only 19 cases positive, with a positive rate of 18.3% (19/104), and the mNGS detection results were positive in 99 cases, with a positive rate of 95.2% (99/104). According to the 19 samples with positive culture, nearly half 47.4% (9/19) of staphylococcus species were positive, and all the positive species were basically epidermal common colonization species or environmental common bacteria. At the same time, we conducted two times of mNGS sequencing for these 19 samples, and the consistency rate between the two sequencing results and the culture results was 84.2% (16/19). According to the results of mNGS detection, 250 species from 110 genera were detected in 99 positive samples. The results of group analysis showed that patients with lower degree of disc degeneration (modified Pfirrmann ≤ 4) and young patients (age < 45 years) had more abundant microbial communities in disc tissue (P < 0.05). Correlation analysis showed that there was a positive correlation between Arcobacter skirrowii and improved Pfirrmann classification at the species level (P < 0.01). There was a negative correlation between pseudomonas thermotolerans and modified Pfirrmann classification (P < 0.05). There was a positive correlation between Staphylococcus hominis and Modic typing scores (P < 0.05). Staphylococcus arlettae was negatively correlated with age (P < 0.05). At the genus level, Arcobacter had a significant positive correlation with the modified Pfirrmann grade and Modic classification (P < 0.05), Corynebacterium had a significant negative correlation with the modified Pfirrmann grade (P < 0.05), and Pseudomonas had a significant negative correlation with age (P < 0.05). After our follow-up of six months to one year, two of the patients included in this study eventually developed severe lumbar disc infection, and the rest did not develop infection.ConclusionsThis study proves that hypotoxic infection may be involved in the degeneration of intervertebral disc, and the bacterial species that cause this occult infection may be more abundant than previously thought. In addition, there was a significant correlation between the biome structure of these bacteria and clinical indicators. The hypothesis of the cause of this insidious infection has the potential to change the way the disease is treated.

PurposeThe relationship between pain experience and biomechanical impairment in chronic low back pain (LBP) is unclear. Among the broader pain literature, sex-based differences in pain experience have been established. However, it is unknown if sex-based differences in pain experience relates to compromised movement patterns for patients with chronic LBP. This study examined sex differences and whether there are sex-based associations between pain experience and biomechanical function in patients with chronic LBP.MethodsTo capture the biomechanical variability among LBP patients, we quantified full-body movement quality based on the extent that 3D postural trajectories deviated from matched controls during a sit-to-stand task (Kinematic Composite Score, K-Score). For both males and females, the K-Score was compared to pain measures, including patient-reported metrics and quantitative sensory testing (pressure pain threshold, PPT).ResultsThere were significant sex-based differences in pain experience and biomechanical function in patients with LBP. Specifically, males exhibited ~ 8% lower trunk K-Scores, indicating biomechanical function that deviated more from controls when compared to female participants (p < 0.001). However, females exhibited PPT values 29% and 41% lower than males at the control and pain sites, respectively (p < 0.0001). There was a weak but significant negative association between PPT and K-Scores for males (R2 = 0.14, p < 0.01), while females lacked an association.ConclusionOverall, males with LBP exhibited worse movement quality, driven by trunk motion, but higher PPTs. Possible explanations include reduced interoceptive awareness or increased kinesiophobia in males, which may influence movement patterns. This research is an initial step in uncovering the complex relationship between patient-specific factors influencing LBP disability, laying the groundwork for further exploration, and paving the way for improving outcomes with patient-specific treatments.

PurposeTo development a nomogram based on clinical features and apparent diffusion coefficient (ADC) of the cervical spinal cord in surgical prognosis in patients with cervical spondylotic myelopathy (CSM).MethodsPatients with CSM who underwent decompression surgery between March and September 2023 were enrolled. Patients underwent conventional cervical spine MRI and sagittal position ZOOM-DWI before surgery. Recovery rate of neurological function was calculated based on the mJOA before and 6 months after surgery. According to recovery rate, patients were divided into good-recovery group (> 50%) and poor-recovery group (< 50%). Clinical- MRI factors model (Model 1) and Clinical-MRI-ADC factors model (Model2) were bulid by multivariate logistic regression to predict. Receiver operating characteristic curve (ROC), calibration curve, and decision curve analysis (DCA) were utilized to compare the predictive performance of the two models. A nomogram based on model 2 was constructed to predict poor recovery rate.Results100 CSM patients were included in this study, including 60 patients in the good-recover group and 40 patients in the poor-recover group. Compared with model 1, the nomogram based on model 2 had a better AUC (0.933vs0.864). The calibration curve of model 2 is closer to the reference line, which indicates that model 2 has better resolution and accuracy. The DCA curve analysis of model 2 also showed better clinical utility. The nomogram based on model 2 performs well in predicting poor recovery rates.ConclusionThe nomogram based on ADC values can effectively predict the outcome of postoperative neurological recovery in CSM patients.

PurposeThe aim of this study was to evaluate bony fusion with Low Dose CT (LDCT) over time following posterior scoliosis surgery in an all screw construct in patients with AIS with special focus on whether the spinal fusion process continue to develop beyond 2 years after scoliosis surgery and to evaluate if LDCT is an adequate radiological method to assess fusion maturation.MethodsTwenty five consecutive patients with mean age 17 (range 13–24) were operated on during 2009–2010 with index diagnosis AIS. Two neuroradiologists used a LDCT protocol to independently evaluate the occurrence and degree of bony fusion at 2 years and 5 years after surgery (ankylosed facet joints). The instrumented spine was divided in an upper, a middle and a lower third on each side in the 25 patients, leaving 150 regions to be assessed. Fusion in each region was classified based on the status of the facet joints as total, partial or non-fusion.ResultsProgression of fusion degree between 2 years and 5 years postoperatively occurred in 18 patients (72%). At 5 years follow-up, 60% showed evidence of total fusion and none showed non-fusion. The interobserver agreement in the classification of bony fusion 2 years postoperatively was almost perfect with a Kappa coefficient of 0.94 and between 2 and 5 years postoperatively a Kappa Coefficient of 0.90.ConclusionsThe fusion maturation progress continues beyond two years following posterior scoliosis surgery in AIS. LDCT is a reliable radiological method to reveal bony fusion maturation over time after posterior scoliosis surgery.

PurposePyogenic spondylodiscitis is a significant health concern, particularly in older individuals. Minimally invasive surgical techniques, such as posterior fixation, are promising for infection control; however, their mechanisms remain unclear. This study aimed to clarify how posterior fixation promotes infection control in an animal model.MethodsThirty female Wistar rats were used to create a pyogenic spondylodiscitis model by injecting methicillin-sensitive Staphylococcus aureus into the intervertebral space between the 6th and 7th coccygeal vertebrae. Three days post-injection, rats were divided into fixation and control groups. The fixation group underwent posterior fixation with an external fixator, whereas the control group underwent screw insertion alone. Bone destruction was assessed via microcomputed tomography on postoperative days (POD) 7, 14, and 21. Immunohistochemistry for cathepsin K and receptor activator of nuclear factor-kappa B ligand (RANKL) was performed on POD 7 samples to assess osteoclast activity.ResultsThe fixation group showed less bone destruction than the control group at POD 14 (35% vs. 56%, p = 0.0007) and POD 21 (30% vs. 52%, p < 0.0001). The cathepsin K-positive area was significantly reduced in the fixation group (p = 0.027). RANKL expression was localized within the intervertebral disc in the fixation group, whereas RANKL was strongly expressed on the bone surface adjacent to the disc in control. The RANKL-positive area was also reduced in the fixation group (p = 0.041).ConclusionsOur combined model of pyogenic spondylodiscitis and posterior fixation supports the theory that posterior fixation stability suppresses RANKL and osteoclast expression, promoting infection control.

PurposeIntervertebral disc degeneration progresses with normal aging; yet common disc grading schemes do not account for age. Degeneration progression also varies between spine levels and is similarly not accounted for by current grading schemes. These limitations inhibit differentiation between discs with normal and expected aging (non-pathological) and discs with accelerated degeneration (which may be pathological). We sought to develop a statistical model to quantify normal age and spine level dependent disc degeneration.MethodsEighty-four asymptomatic adult subjects ranging evenly from 18 to 83 years old underwent magnetic resonance imaging (MRI) of the lumbar spine. Subject traits, MRI-derived disc geometry, and MRI biomarkers of T2 relaxation time were evaluated and used to develop a statistical model to predict effective disc age, the age at which normal aging would produce a disc’s observed phenotype.ResultsAfter evaluating several models, a 4-predictor model utilizing 1) subject height, 2) nucleus pulposus T2 relaxation time, 3) disc mid-sagittal area and 4) disc 3D volume, optimally estimated effective disc age. The effective age closely tracked true age for spine levels L1-L5 (R2 ≈ 0.7, RMSE ≈ 10 years) and moderately tracked true age for L5-S1 (R2 = 0.4, RMSE = 14 years). The uncertainty in the effective disc age prediction was ± 3 years as assessed by fivefold cross validation.ConclusionWe offer a data-driven, quantitative tool to quantify normal, expected intervertebral disc aging. This effective age model allows future research to target discs with accelerated degeneration.

Background contextCauda Equina Syndrome (CES) is an emergency clinical syndrome with correlating radiological evidence of spinal compression. Urgent recognition and treatment is key. In many units, it lacks a clear pathway of investigation and referral, despite a constantly expanding evidence base for its management.PurposeThe aim of this article is to provide a systematic review of currently available guidelines internationally, and also an up-to-date review of current key evidence on topics central to the accurate assessment and investigation of CES.Study designA systematic review of the literature was carried out to identify all previously published or proposed pathways internationally for CES.MethodsIncluded articles were reviewed and data extracted and collected in excel format. Data extracted included year of publication, author, time to MRI in pathway, inclusion or exclusion of post void residual measurement and specific cauda equina red flags used. An evidentiary review was also carried out on key topics including digital rectal examination.ResultsFollowing removal of duplicates a total of 307 articles underwent title and abstract screening from which 9 were eventually included for data extraction. All included papers recommended urgent MRI with the presence of red flag findings. Red flags included in all papers were perianal/perineal/saddle sensory disturbance and bladder or bowel dysfunction of varying specifications. 8/9 papers included radicular/sciatic pain, 5/9 included new motor weakness, 4/9 included DRE findings and PVR was included in 5/9 papers. PVR and DR examinations retain clinical significance.ConclusionWhile specific guidelines show minor variability, overall the current literature presents a consensus that in cases of suspected cauda equina syndrome MRI should be carried out on an urgent basis.

PurposeThis study aimed to investigate the associations between electromyography (EMG) activity and key muscle quality parameters, including cross-sectional area (CSA), functional cross-sectional area (FCSA), fat area (FA), and fat infiltration (FI), in individuals with chronic low back pain (cLBP) and those without back pain (no-BP). The objective was to explore how variations in muscle quality affect muscle activation patterns in the erector spinae (ES) and multifidus (MF) muscles during a standardized lifting task in both groups.MethodsA total of 102 participants were enrolled, comprising 60 individuals with cLBP and 42 without back pain. Muscle activation was measured using a bipolar wireless EMG system during the performance of a 10 kg lifting task. Magnetic resonance imaging (MRI) was utilized to assess muscle quality indicators (CSA, FCSA, FA, and FI) at the L3 level for the ES muscle and the L5 level for the MF muscle. Linear regression models were applied to examine the associations between EMG activity and muscle quality metrics, with adjustments for age, sex, and body mass index (BMI).ResultsIn the no-BP group, significant negative associations were found between CSA, FCSA, and EMG activity in the ES muscles (p < 0.05). However, in the cLBP group, no significant associations were observed between CSA or FCSA and EMG activity. Instead, there was a significant negative association between EMG activity and FA/FI in the ES muscles of the cLBP group (p < 0.05).ConclusionMuscle quality, particularly fat infiltration, appears to have a greater impact on the amplitude of muscle activities in cLBP patients compared to CSA and FCSA. In contrast to the no-BP group, CSA and FCSA were not significantly associated with muscle activation in the cLBP group, highlighting the need for rehabilitation strategies focused on reducing fat infiltration to improve muscle performance in these patients.

PurposeThe rate of lumbar spine surgeries has increased and the postoperative course is influenced not only by physical but also psychological factors. Patients with pre-existing psychological disorders appear to be more likely to develop anxiety and depression, these factors could negatively affect pain perception, disability, and quality of life. A systematic review and metanalysis were performed to determinate which psychological factors impact on spinal postoperative clinical outcomes and how it can influence postoperative clinical outcomes in patients undergoing spinal surgery.MethodsA Systematic literature review was performed on the following databases: PubMed/ MEDLINE, Scopus, Psychinfo and Web of Science on October 2022. The quality of the included studies was assessed using the ROBINS-E tool (Risk Of Bias In Non-randomized Studies - of Exposures). This review was registered at Prospero CRD42022380777. Meta-analysis was performed to compare back pain, leg pain disability, quality of life between the group of patients with psychological issues and control groups as continuous outcomes.ResultsOf the identified 1756 studies, eventually 13 studies were included with a total of 5364 patients. Our results suggest that patients affected by anxiety and depression report worse back pain (MD 0.40, 95% CI 0.20 to 0.62, p = 0.0001) and disability (MD 9.58 95% CI 2.67 to 16.48, p = 0.007) levels after spine surgery than patients with healthy mental status. Instead quality of life and leg pain don’t show significant differences between the two groups.ConclusionOur findings demonstrate a correlation between presence of mental disease and the worsening of post-surgical clinical outcomes. Anxiety and depressive symptoms can influence pain and disability symptoms during the postoperative phase.