Degenerative disc disease (DDD) and chronic low back pain are prevalent in the general population and athletic populations exposed to high spinal loading. Environments with simulated microgravity, such as dry immersion, water immersion, and parabolic flight, may mimic the spinal unloading experienced in space and have shown potential in enhancing disc hydration, reducing axial stress, and promoting recovery. In this narrative review, we evaluate the therapeutic potential of short-term simulated microgravity exposure for spinal rehabilitation and athletic recovery, highlighting mechanisms and clinical applications. A comprehensive literature search was conducted in PubMed, EMBASE, Web of Science, and EBSCO, following the PICOS framework. Studies involving simulated or real microgravity and reporting outcomes related to disc hydration, extracellular matrix remodeling, biomechanical properties, or molecular signaling were included. A total of 9 original research articles met the inclusion criteria. Short-term microgravity exposure increases intervertebral disc hydration and disc height while stimulating the synthesis of proteoglycans in the matrix. Mechanistically, these effects are mediated by a reduction in axial loading, osmotic water influx, and the activation of pathways such as the transforming growth factor-β (TGF-β)/Smad3 pathway. Clinically, simulated microgravity may serve as a noninvasive modality for recovery in athletes with spinal overload, offering alternatives to conventional therapies via parabolic flight, aquatic therapy, or dry immersion. Simulated microgravity represents a novel, noninvasive modality that may aid in spinal rehabilitation by enhancing disc hydration and reducing mechanical stress. While early evidence is promising, further clinical trials are needed to validate the safety, efficacy, and integration of simulated microgravity into multidisciplinary sports medicine protocols.
Abbreviations: DDD = degenerative disc disease, ECM = extracellular matrix, GAG = glycosaminoglycan, LBP = low back pain, ODI = Oswestry Disability Index, PICOS = Population, Intervention, Comparison, Outcome and Study Design, RWV = rotating wall vessel.
Aggrecan is the principal determinant of water retention in the nucleus pulposus and a core regulator of intervertebral disc mechanics. This review synthesizes evidence on aggrecan alterations during intervertebral disc degeneration (IVDD), associated upstream drivers, and current approaches for assessment and therapy. Based on published literature, we present the first comprehensive, 4-part classification of aggrecan modifications observed across degeneration: (1) a reduced chondroitin sulfate–to–keratan sulfate ratio; (2) increased enzymatic cleavage of the core protein; (3) decreased core protein expression; and (4) exacerbated hyaluronic acid degradation. These shifts converge on loss of fixed charge density and osmotic pressure, reduced water content, and altered tissue mechanics in the degenerating disc. We further provide the first integrative synthesis of upstream drivers linked to these aggrecan alterations, systematizing them into a convergent set that includes hypoxia, metabolic dysregulation with lactate accumulation and acidosis, inflammatory cytokine signaling, and osmotic imbalance. For assessment, we outline conventional biochemical/chemical assays for proteoglycans and glycosaminoglycans and summarize emerging readouts that infer aggrecan or glycosaminoglycan content and may aid early evaluation. From a therapeutic standpoint, current strategies fall into 2 broad categories. Restorative approaches attempt to mitigate 1 or more modification domains—most commonly via anti-inflammatory signaling control or modulation of matrix-degrading enzymes—but typically focus on single targets and may not address the multifactorial nature of degeneration. Substitution approaches seek to supplement water-retaining function with aggrecan-mimicking materials; although several candidates reproduce key biophysical features in vitro, in vivo validation in disc models remains limited. Collectively, these findings position aggrecan as a molecular and biophysical anchor for understanding IVDD and designing interventions. Future work should prioritize multitarget repair strategies that address the convergent drivers identified here and support in vivo evaluation of aggrecan substitutes to restore osmotic function and matrix homeostasis in nucleus pulposus (NP).
Abbreviations: IVDD, intervertebral disc degeneration; NP, nucleus pulposus; AF, annulus fibrosus; ECM, extracellular matrix; GAG, glycosaminoglycan; CS, chondroitin sulfate; KS, keratan sulfate; HA, hyaluronic acid; MMP, matrix metalloproteinase; ADAMTS, a disintegrin and metalloproteinase with thrombospondin motifs; TNF-α, tumor necrosis factor-alpha; IL-1β, interleukin-1 beta; SDC4, syndecan-4; HYAL, hyaluronidase; gagCEST, glycosaminoglycan chemical exchange saturation transfer; HR-MAS NMR, high-resolution magic-angle spinning nuclear magnetic resonance; BPG, biomimetic proteoglycan.
Whether the first coronal reverse vertebrae (FCRV) can directly cause biomechanical changes in adjacent segments remains unclear. This study aimed to explore the biomechanical changes in adjacent discs of FCRV to better understand the stress distribution of degenerative lumbar scoliosis. According to the plain computed tomography scan data of the T11–L1 segment of a degenerative lumbar scoliosis patient, T12 was the FCRV, and a 3-dimensional finite element model was established accurately. The T11–12 segment disc was defined as the adjacent upper disc (UD), axial section as half of the UD. Similarly, T12–L1 disc was the adjacent lower disc (LD), axial section as half of the LD. The biomechanical changes in adjacent discs of the FCRV under different loads were assessed. Rotational load was the highest under different loads, but it is usually instantaneous. It was noted that the LD was subjected to significantly greater stress magnitudes under neutral standing. Although the adjacent discs of the FCRV did not differ significantly with regard to shear stress, a striking difference was noted when the concave and convex sides were considered individually. The concave sides of the adjacent disc were subjected to greater stress under the neutral standing or lateral bending compared with the convex side. Furthermore, the concave sides of the UD, half of the UD (HUD), and HLD were subjected to significantly greater stress under the neutral standing compared with the convex side. The distal adjacent disc of the FCRV may be at greater risk of degeneration because of taking on more force. These findings can contribute to further treatment planning for the patient and aid physicians' management decision-making. FCRV first coronal reverse vertebrae, DLS = degenerative lumbar scoliosis, UD = upper disc, HUD = half of the upper disc, LD = lower disc, HLD = half of the lower disc, FE = finite element, LLB = left lateral bending, RLB = right lateral bending, LAR = left axial rotation, RAR = right axial rotation, NS= neutral standing
Osteoporotic vertebral compression fractures (OVCFs) are common among the elderly, and percutaneous vertebroplasty (PVP) is the standard minimally invasive procedure for treating OVCF, but previous PVP mainly uses X-ray fluoroscopy, which poses additional radiation and complication risks to patients. To explore the clinical efficacy of PVP for treating OVCFs with the assistance of mixed reality (MR) navigation technology. Forty OVCF patients were tested in the prospective, randomized, and controlled study and were randomly grouped into MR-guided group and conventional fluoroscopy group with 20 patients, respectively. The indicators such as surgery duration, number of fluoroscopy, pain scores, and surgical complications between both groups were evaluated. The comparison between the MR-guided group and the control group in terms of surgical duration, number of fluoroscopy, bone cement dosage, and bone cement leakage showed that the MR-guided group (26.00 minutes [26.00–27.75]) had a significantly shorter surgical duration than that of the control group (29.00 minutes [27.25–34.25]) (p < 0.001). The MR-guided group (26.00 times [25.25–32.75]) had a fewer number of total fluoroscopy than that of the control group (35.00 times [31.00–41.00]) (p < 0.05), a higher bone cement dosage than that of the control group (p < 0.05), and the bone cement leakage rate is lower in the MR-guided group (10.00%) compared with the control group (30.00%); however, there was no statistically significant difference (p > 0.05). Pain relief and vertebral height restoration postoperative and during follow-up were comparable between the 2 groups (p > 0.05). MR-guided PVP surgery for the treatment of OVCF can significantly reduce surgical duration, the number of punctures, the number of fluoroscopy, radiation exposure to both patients and medical staff, and the risk of surgery-related complications and featured as a safe, precise, and efficient auxiliary technology that merits wider application in minimally invasive spinal surgery.
Anterior lumbar interbody fusion (ALIF) is a widely adopted technique for managing lumbar degenerative disorders. However, comprehensive analyses of its research trends, technological developments, and public engagement are still lacking. This study examines the research landscape, public perception, and innovation trends in ALIF, while also evaluating data extraction methods for managing ALIF-related information. ALIF-related data from Web of Science, YouTube, and Lens were analyzed. Bibliometric analysis explored international collaborations, key authors, and leading journals. Artificial intelligence models were used to extract information on surgical techniques, diseases, and evaluation metrics. Sentiment analysis categorized YouTube comments as positive, negative, or neutral, while patent data were assessed based on jurisdiction, application type, and legal status. A total of 660 publications, 1311 YouTube comments, and 53 patents were identified. Scientific output increased, peaking in 2021, with the United States (USA) leading in collaborations and author contributions. Neurosurgeons accounted for most ALIF-related publications. World Neurosurgery published the highest number of ALIF articles among top journals from 2017 to 2023. Patents were largely focused on ALIF implants, with half still active. YouTube comments peaked in 2022, with sentiment analysis showing 41.6% positive responses, 36.2% neutral, and 22.2% negative responses. ALIF research has grown significantly in academic output, technological innovation, and public engagement. The USA, China, and South Korea are major contributors, maintaining strong collaborations. Neurosurgeons possess extensive experience in ALIF surgical techniques, and the interest in ALIF-related articles in WORLD NEUROSURGERY has been progressively increasing. Artificial intelligence models demonstrated effectiveness in extracting surgical data, though challenges remain with disease-related information. The rise of ALIF-related YouTube content and sentiment analysis findings highlight growing public interest, with generally positive perceptions. AI = artificial intelligence; ALIF = anterior lumbar interbody fusion.
The recognition of shoulder imbalance in patients with adolescent idiopathic scoliosis (AIS) has garnered increasing attention among spine surgeons. Nevertheless, there is an inconsistency in the definitions of shoulder imbalance, and the relationships between radiological parameters and patient satisfaction remain inadequately explored. This study aimed to determine the correlated shoulder imbalance parameter leading to patient acceptable symptom state (PASS) for Lenke 1/2 AIS patients after correction surgery, based on Scoliosis Research Society-22r questionnaires. Lenke 1/2 type patients from 2 tertiary hospitals undergoing pedicle-screw fixation and correction surgery from 2017 to 2021 were enrolled. One patient who replied positively to both No. 21 and 22 questions was defined as achieving PASS. Basic patient information and shoulder imbalance parameters were calculated and compared pre-surgery and at follow-up (at least 24 months). Binary logistic regression analysis and receiver operating characteristic (ROC) curve were performed. One hundred twenty-eight patients (99 females, mean age 14.8 years) were enrolled. A total of 105 (82.0%) achieved PASS. Clavicle-chest cage angle difference (CCAD) was an independent risk factor correlated with treatment satisfaction (odds ratio = 0.674, p = 0.01), with a cutoff value of 7.3° (area under the curve: 0.75, 95% CI: 0.655–0.846; sensitivity: 91.7% and specificity: 64.4%). In Lenke 1/2 AIS patients, there was a significant correlation between CCAD and the state of PASS. Patients were more inclined to be satisfied with surgical treatment when the CCAD was less than or equal to 7.3°. AIS = adolescent idiopathic scoliosis, AUC = area under the curve, CA = clavicle angle, CCAD = clavicular–thoracic cage angle difference, CHD = coracoid height difference, CRID = clavicle-rib cage intersection difference, FRA = first rib tilt angle, MTC = main thoracic curve, PASS = patient acceptable symptom state, PSI = postoperative shoulder imbalance, ROC = receiver operating characteristic, RSH = radiographic shoulder height, SRS = Scoliosis Research Society, T1T = T1 tilt.
Crowned dens syndrome (CDS) is clinically characterized by acute cervical pain accompanied by peri-odontoid calcifications. Historically considered rare, recent literature and our clinical findings suggest CDS is not uncommon. This study aimed to evaluate the prevalence, etiology, clinical manifestations, imaging features, and treatment outcomes of CDS. We retrospectively analyzed clinical data from 50 CT-confirmed CDS patients admitted to Guangxi International Zhuang Medicine Hospital between January 2019 and March 2025. Patients were stratified into symptomatic CDS (n = 26) and asymptomatic CDS (n = 24) groups based on the presence of acute neck pain and restricted cervical mobility. Collected data included demographics (gender, age, and smoking/alcohol history), comorbidities (hypertension, diabetes), initial clinical departments, and imaging findings. All symptomatic patients were followed to document treatments and symptom recurrence. Among 50 radiologically confirmed CDS cases, 26 (52.0%) were symptomatic and 24 (48.0%) were asymptomatic. Calcifications were observed in all peri-odontoid regions on imaging. The overall male-to-female ratio was 19:31 (ratio = 0.61). Symptomatic CDS patients showed significantly higher proportions of females (p < 0.05) and older age (p < 0.05) compared with asymptomatic cases. Age and female gender correlated significantly with symptomatic CDS, while smoking, alcohol use, hypertension, and diabetes showed no significant association. All symptomatic patients achieved substantial symptom relief with nonsteroidal anti-inflammatory drugs or corticosteroid therapy, including recurrent cases. Current under-recognition of CDS contributes to high rates of misdiagnosis and underdiagnosis, suggesting its true incidence likely exceeds reported data. Computed tomography (CT) imaging provides definitive diagnostic evidence. Early intervention with nonsteroidal anti-inflammatory drugs or corticosteroids is critical for improving outcomes in symptomatic CDS patients. CDS = crowned dens syndrome, CPPD = calcium pyrophosphate dihydrate, CRP = C-reactive protein, CT = computed tomography, HU = Hounsfield units, NSAIDs = nonsteroidal anti-inflammatory, TLA = transverse ligament of the atlas.
Vertebral bone quality (VBQ), which critically influences spinal fusion outcomes, can be quantitatively assessed by the VBQ score—a radiation-free metric sensitive to marrow fat changes and increasingly used to predict postoperative complications such as implant failure. The study was aimed to evaluate the predictive value of the VBQ score for internal fixation failure after PLIF, and to explore factors influencing VBQ cut-off value. This study aimed to evaluate the predictive value of VBQ score for internal fixation failure (IFF) after posterior lumbar interbody fusion (PLIF), and to explore factors influencing VBQ cutoff value. A retrospective study was conducted on patients who underwent PLIF at Chinese People's Liberation Army General Hospital from January 2017 to December 2022. IFF requiring revision was used as the endpoint. Predictive performance was assessed using the receiver operating characteristic (ROC) curve and Youden index to determine the cutoff value. Logistic regression analyses were used to identify influencing factors. Pearson correlation was used to assess associations. A total of 256 patients were included in this study, with a mean age of 68.73 ± 6.32 years, and 74% were female. Sixty-seven patients experienced IFF, while 189 did not. The mean VBQ score was significantly higher in the IFF group compared to the nonfailure group (3.62 ± 0.46 vs. 2.97 ± 0.43, p < 0.001). Receiver operating characteristic curve analysis revealed that the VBQ score had good predictive value for IFF, with an area under the curve of 0.859 (95% confidence interval: 0.81–0.91). The optimal cutoff value was 3.3, with a sensitivity of 77.6% and specificity of 79.9%. Multivariate analysis confirmed that the VBQ cutoff value was not affected by demographic variables. VBQ score was associated with gender, chronic disease, and IFF. VBQ score is an excellent screening tool for predicting internal fixation failure following PLIF, which can provide a key basis for preoperative intervention in high-risk patients. BMD = bone mineral density, CI = confidence interval, CSF = cerebrospinal fluid, DEXA = dualenergy X-ray absorptiometry, IFF = internal fixation failure, MRI = magnetic resonance imaging, PLIF = posterior lumbar interbody fusion, QCT = quantitative computed tomography, ROC = receiver operating characteristic, SI = signal intensity, VBQ = vertebral bone quality.
Spinal neoplastic lesions are traditionally managed through staged procedures, potentially introducing delays in oncologic care. Single-stage percutaneous approaches may optimize treatment timelines while maintaining diagnostic accuracy and structural stability. This study aimed to evaluate whether single-stage percutaneous biopsy and stabilization reduce time to definitive oncologic therapy and improve patient-reported outcomes compared with staged procedures in adults with mechanically unstable spinal neoplastic lesions of uncertain histology. A retrospective cohort study analyzed 65 consecutive patients with spinal neoplastic lesions managed between November 2020 and May 2025. Patients were categorized into single-stage (n = 21) and staged (n = 44) groups based on whether percutaneous biopsy and stabilization were performed during the same operative session or as separate procedures. Primary outcome was the time from biopsy to initiation of definitive oncologic therapy. Secondary outcomes included changes in health-related quality of life assessed using visual analogue scale and Spine Oncology Study Group Outcomes Questionnaire, measured at baseline and at histopathological diagnosis availability. Baseline characteristics were comparable between groups. Mean time from biopsy to definitive therapy was significantly shorter in the single-stage cohort (30.2 days, 95% confidence interval: 24.5–35.9) versus staged cohort (40.1 days, 95% confidence interval: 36.7–43.5), representing a 9.9-day reduction (p = 0.008). At histopathological diagnosis, single-stage patients reported significantly lower pain scores (visual analogue pain assessment scale 4.3 vs 6.9, p < 0.001), superior physical function (77.7 vs 65.5, p = 0.002), and higher overall quality of life (SOSGOQ2.0 total 63.2 vs 57.0, p = 0.015). Adverse event rates were comparable between groups, with no significant difference in complications or repeat procedures. Single-stage percutaneous biopsy and stabilization accelerate oncologic care initiation and improve early patient-reported outcomes without compromising safety, representing a preferred pathway for managing mechanically unstable spinal neoplastic lesions. CI = confidence interval, HRQoL = health-related quality of life, SINS = Spinal Instability Neoplastic Score, VAS = visual analogue pain assessment scale.