Search Results (160)

Adjacent segment degeneration remains a major biomechanical concern after lumbar fusion, whereas fully dynamic topping-off constructs may provide an alternative strategy by preserving segmental motion and unloading degenerated discs. In this study, a three-dimensional nonlinear finite element model of the L1-L5 lumbar spine with L3-L5 double-segment degeneration was developed to compare transforaminal lumbar interbody fusion (TLIF)-based pedicle screw fixation systems (PSFS) and Bioflex-based pedicle screw dynamic stabilization systems (PSDSS). Three interspinous process spacers, namely DIAM, Wallis, and Coflex-F, were implanted at L3-L4, and three pedicle screw diameters of 6.5, 5.5, and 4.5 mm were evaluated under flexion and extension to quantify screw-rod parameter sensitivity. The results showed that both TLIF- and Bioflex-based topping-off constructs reduced intradiscal pressure (IDP) and restricted excessive range of motion (ROM) at the transition segment, especially during extension, with a maximum L3-L4 IDP reduction of 39.49% compared with the degenerated model. Compared with fusion-based constructs, Bioflex-based PSDSS provided greater surgical-segment unloading, reducing L4-L5 IDP by 55.07% in extension and 25.30% in flexion. However, this motion-preserving effect was accompanied by higher pedicle screw stress sensitivity; in the 4.5 mm Bioflex model, the average L4 screw stress reached 15.62 MPa in flexion, representing a 51.71% increase compared with the 6.5 mm screw. In contrast, PSFS constructs showed greater stress variation in the rigid connecting rods. Overall, under the present modeling assumptions, Bioflex-based fully dynamic topping-off constructs showed more favorable disc unloading and transition-segment motion regulation than fusion-based configurations, but their biomechanical benefit should be balanced against diameter-dependent pedicle screw stability. Full article

Background: Posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) is a standard procedure with recognized long-term complications that may emerge years after surgery. Informed consent requires disclosure of material risks, but it is unclear whether these long-term sequelae are consistently communicated. This study systematically reviewed publicly available consent materials to assess disclosure of evidence-based long-term complications of PSF for AIS. Methods: Official websites of spine, orthopedic, and neurosurgical societies, along with major hospitals across North America, South America, Europe, and Australia, were searched for publicly available informed consent forms and patient information leaflets related to PSF for AIS. Documents were assessed for explicit mention of predefined long-term complications: chronic pain/health-related quality of life, pseudoarthrosis, adjacent segment degeneration, future surgery, pulmonary function impact, late infection, local tissue reaction to metal debris, and pregnancy-related issues. Disclosure frequencies were calculated. Results: Thirty-one documents from ten countries were included. Immediate perioperative risks were almost universally reported, whereas long-term complications were inconsistently disclosed. Reporting frequencies were: pseudoarthrosis, 80.6% (n = 25); future surgery, 67.7% (n = 21); adjacent segment degeneration, 51.6% (n = 16); chronic pain, 48.4% (n = 15); local tissue reaction to metal debris, 38.7% (n = 12); late infection, 25.8% (n = 8); pregnancy-related issues, 22.6% (n = 7); and pulmonary impact, 9.7% (n = 3). Conclusions: Publicly available consent materials for AIS surgery incompletely disclose long-term complications compared with the published evidence. However, written information sheets and consent forms represent only one component of the consent process. Consistently with the patient-centered standard articulated in Montgomery v Lanarkshire Health Board, informed consent should include discussion of material risks, benefits, reasonable alternative treatments including standard care, and the option of no treatment, with disclosure tailored to what matters to the patient and family. Updating written materials to better reflect lifelong risks may strengthen one important component of informed consent and shared decision-making for patients and families. Full article

Background and Objectives: Low back pain (LBP) is a leading cause of disability worldwide and is frequently associated with intervertebral disc degeneration (IVDD). Current therapeutic strategies are primarily symptomatic and do not restore native disc biology, largely due to the avascular nature of the intervertebral disc and the hostile inflammatory and mechanical microenvironment that characterizes degeneration. The aim of this study is to provide an updated and clinically oriented overview of the pathophysiology of IVDD and to evaluate the current evidence on mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP)-based therapies. Materials and Methods: A focused narrative literature review was performed to evaluate current evidence on MSC- and PRP-based therapies for intervertebral disc degeneration (IVDD). The search was conducted in PubMed. Only studies in English were considered eligible. Results: Mesenchymal stem cells (MSCs) demonstrated regenerative and immunomodulatory effects primarily through paracrine mechanisms, enhancing extracellular matrix synthesis and reducing inflammation and apoptosis. MSC-derived extracellular vesicles emerged as a promising cell-free alternative, potentially overcoming limitations related to cell survival and safety. Platelet-rich plasma (PRP) showed anabolic and anti-inflammatory properties, promoting disc cell proliferation and matrix production, particularly in early-stage degeneration. Clinical studies, including randomized trials, reported significant improvements in pain and function for both MSC and PRP therapies, with favourable safety profiles. However, heterogeneity in treatment protocols and limited long-term data remain significant limitations. Orthobiologic therapies represent a minimally invasive option for patients with discogenic low back pain refractory to conservative treatment. Patient selection is crucial and should consider degeneration stage, disc viability, and clinical presentation. PRP is primarily indicated in early-stage degeneration (Pfirrmann II–III), whereas MSC-based therapies may be considered in selected patients with more advanced but still viable discs. Based on current evidence, a stepwise approach is proposed, progressing from conservative management to PRP, MSCs, and ultimately surgery. Orthobiologics should be integrated within a multimodal strategy including rehabilitation. Conclusions: MSCs and PRP represent a promising and, eventually, complementary orthobiologic therapies for IVDD. PRP is primarily effective in early degenerative stages as a biologic stimulator, whereas MSCs may provide regenerative benefits in more advanced but still viable discs. Further studies are necessary to standardize protocols and confirm long-term efficacy and safety. Full article

Objective: Back pain is a multifactorial condition commonly associated with degenerative spinal changes. Spondylophytes are frequent outgrowths of the vertebral bodies that may be influenced by arterial hypertension via a possible increased pulsation of the aorta and its effects on bone remodeling. If it can be demonstrated that an increased pulse pressure in the aorta due to hypertension promotes the growth of spondylophytes and thereby increases the likelihood of back pain, future studies may investigate how the effectiveness of blood pressure management can be improved in order to reduce the prevalence of degenerative changes in the spine and, consequently, prevent back pain. This study investigated the association between arterial hypertension and thoracic spondylophyte formation using whole-body MRI data from the population-based Study of Health in Pomerania (SHIP). Materials and Methods: Spondylophyte presence and area were assessed for their association with hypertension status in 859 SHIP-START-3 participants who underwent whole-body MRI. Right-sided spondylophytes at T8-T11 were measured on axial T2-weighted sequences. Hypertension was defined by self-report or antihypertensive medication use; a sensitivity analysis was conducted using the 2024 European Society of Cardiology definition (systolic blood pressure ≥ 140 mmHg). Multivariate regression models adjusted for age, sex, obesity, and smoking were used to assess associations. Machine learning algorithms were applied for validation. Results: Spondylophytes were present in 87.7% of participants. Hypertension was significantly associated with spondylophyte presence (OR = 2.07, 95% CI: 1.15–3.81) but not consistently associated with spondylophyte size. Spondylophyte size increased from T8 to T11, and was associated with age, male sex, and obesity. Sensitivity analyses widely confirmed robustness of the analysis. Conclusions: This population-based MRI study investigates the still insufficiently studied relationship between arterial hypertension and the formation of thoracic spondylophytes. The findings are consistent with the hypothesis that hypertension may be associated with spinal bone remodelling, though causal inference remains limited by the cross-sectional study design. Further longitudinal studies are needed to clarify causality and clinical relevance for spinal degeneration and back pain. Full article

Finite element analysis is widely used to study spinal biomechanics and to compare surgical strategies under controlled loading conditions. By allowing variation in alignment, fixation, and implant design, these models provide insight into stress redistribution and motion changes that are difficult to isolate experimentally. This review examines spine surgery-focused finite element studies published between 2018 and 2024, with emphasis on interbody fusion techniques, adjacent segment mechanics, and implant-related stress behavior. Across lumbar fusion models, constructs incorporating anterior column support demonstrate lower posterior instrumentation stress than posterior-only approaches, with lateral lumbar interbody techniques showing reduced rod and screw stresses across multiple loading conditions compared with posterior lumbar interbody or posterolateral fusion constructs. In the cervical spine, comparisons of plated and zero-profile anterior cervical discectomy and fusion devices show smaller increases in adjacent-level motion and intradiscal pressure with zero-profile constructs, alongside higher localized stress at fixation interfaces. More recent studies apply finite element methods to implant optimization, alignment planning, and patient-specific modeling. Together, these findings suggest that finite element analysis is increasingly used to support surgical planning and implant design, with continued advances in validation and patient-specific simulation likely to strengthen its clinical relevance. Full article

Cervical spondylosis is a common cause of spinal cord dysfunction, and anterior cervical discectomy and fusion (ACDF) is widely employed when conservative treatment fails. Conventional implant systems such as the cervical cage with plate (CCP) and zero-profile stand-alone cage (ZPSC) are commonly used to enhance spinal stability and promote fusion, but they are associated with complications including dysphagia and adjacent segment degeneration. To address these limitations, a novel flexible plate cage system (FPCS) has been developed to optimize biomechanical performance while minimizing surgical risk. In this study, a finite element model of the C3–T1 cervical spine was constructed to simulate ACDF at the C5–C6 level using CCP, ZPSC, and FPCS implants. Under standardized loading conditions, von Mises stress was analyzed in the bone, intervertebral disc, endplates, cage, and screws, using the mean of the top 5% stress values to ensure accuracy. All surgical models showed increased stress compared to the intact reference spine. The ZPSC model exhibited the highest stress in the cage and screws, suggesting a more concentrated load path. The CCP model showed a more evenly distributed stress profile, particularly affecting the inferior adjacent segment. The FPCS model demonstrated moderate cage stress, reduced screw stress, and the highest plate stress, indicating a design that effectively redirects mechanical load from the screw-bone interface toward the anterior plate. This may be related to the unique structural configuration of the FPCS, which secures screws horizontally into the anterior vertebral body without penetrating the endplates. These findings suggest that the FPCS may offer a biomechanically favorable alternative to existing ACDF implants. Full article

Total hip arthroplasty (THA) reliably restores function, yet instability remains a clinically relevant complication. Increasing evidence indicates that postoperative stability is strongly influenced by the dynamic spine–pelvis–hip interaction, which modulates functional acetabular orientation across postures. This narrative review summarizes current evidence on postoperative spinopelvic alignment changes after THA with emphasis on temporal patterns, underlying mechanisms, and predictive factors. Early after THA, restoration of hip motion can partially normalize hip-driven compensatory patterns, however substantial interindividual variability persists. Mid- to long-term follow-up shows that pelvic orientation continues to evolve, particularly progressive posterior pelvic tilt in standing, largely driven by aging and spinal degeneration, with acceleration in older patients and those with spinal pathology. Prediction of postoperative pelvic behavior requires integrated assessment of pelvic orientation, spinal alignment and mobility, contralateral hip status, and whether imbalance is hip-driven versus spine-driven. Although classification- and model-based approaches can estimate postoperative pelvic tilt, clinically meaningful prediction uncertainty remains, supporting a strategy focused on risk stratification and adaptive preoperative planning. Full article

Background: Hypermobile Ehlers–Danlos syndrome (hEDS) can present as a complex interplay of widespread symptomatology and multisystem involvement, posing diagnostic and treatment challenges. Objective characterization of cervical spine and neurovascular findings in hEDS has been limited. Previous studies have emphasized upper cervical spine complications in hEDS, yet the relevance and mechanisms underlying associated symptomatology have not been elucidated. This study examined objective test findings in patients with hEDS at an outpatient neck clinic to explore cervical spine and neurovascular pathology that could contribute to further understanding the clinical profile of a subset of patients with hEDS. Methods: This single-center, retrospective observational study included patients with hEDS aged 20–50 years from 1 January 2022–31 December 2024, at an outpatient neck center. It excluded previous neck surgery, traumatic events, or related injury. Demographic, clinical, and diagnostic data were collected through a retrospective chart review, including measurements from standard clinical diagnostic protocols: digital motion X-ray (videofluoroscopy), cone beam CT, Doppler ultrasound, and tonometry. Results: More than 71% of patients reported ≥29 symptoms. Nearly all patients exhibited co-occurring forward head, decreased depth of curve, ligamentous cervical instability, and decreased internal jugular vein (IJV) and vagus nerve cross-sectional area (CSA). Vagus nerve CSA was found to be significantly smaller than the comparative healthy/normal population. IJV CSA was significantly smaller at C1 than at C4–C5, suggesting evidence of carotid sheath compression at C1. Conclusions: This study offers novel evidence that cervical spine pathology, IJV compression, and vagus nerve degeneration are uniformly prevalent in hEDS, which may contribute to, or be an etiological basis for, the multisystem involvement in a subset of patients with this disorder. These findings provide hypothesis-generating data to inform future mechanistic and therapeutic studies, including exploration of new diagnostic and treatment targets. Full article

Background: Children’s behavior and lifestyle are changing rapidly, potentially exceeding the capacity of physiological adaptation. Contemporary lifestyles may negatively affect spinal development and contribute to dysfunction and premature degeneration. Despite the increasing prevalence of postural changes, cervical spine disorders in adolescents remain under-researched. Methods: This narrative review is based on a comprehensive search of PubMed/MEDLINE and Scopus. The search strategy included a broad review of anatomical and biomechanical literature from the past 25 years and a focused review of studies from the last 15 years to reflect recent generational changes. Results: The immature spine has distinct structural and biomechanical characteristics that increase susceptibility to maladaptive responses to unbalanced forces. High screen time is associated with sedentary behavior and increased consumption of ultra-processed foods, which may affect metabolic health and musculoskeletal development. Childhood and adolescent obesity are increasingly prevalent and may influence spinal development, including through myosteatosis. Data on the consequences of cervical and lumbar lordosis loss in adolescents remain limited. Although degenerative spinal disorders are well recognized in adults, their identification in younger populations may be inadequate. Conclusions: Modern lifestyle factors pose a growing risk to children’s spinal health through complex interactions among behavioral, metabolic, and biomechanical mechanisms. The developing spine’s vulnerability and the coexistence of multiple, interrelated risk factors support the need for integrated preventive strategies rather than single-factor interventions. Future studies should focus on models capturing these interactions and their long-term consequences. Full article

Diagnosing cervical spine instability with flexion-extension radiographs is challenging, as current guidelines are based on limited cadaver studies and do not adequately account for level, vertebral size, or patient effort. There is a need for automated cervical instability metrics anchored to normative reference data, accompanied by evidence on how often abnormal findings occur in real clinical populations and which soft-tissue injury patterns they can detect. We developed and evaluated fully automated, radiographic-based cervical intervertebral motion (IVM) metrics—adapted from prior lumbar methods—using an FDA-cleared analysis pipeline that segments C2–C7 and derives rotation, translation, disc heights, and regression-based instability indices. Normative reference data were first established from flexion-extension radiographs of 341 asymptomatic volunteers after excluding radiographically degenerated levels. Abnormality prevalence was then estimated in two symptomatic cohorts: pooled preoperative clinical-trial radiographs and 881 patients with symptoms attributed to motor-vehicle accidents, excluding levels with <5° rotation to reduce unreliable data due to insufficiently stressed spines. Finally, potential diagnostic performance was assessed in a controlled cadaveric ligament-sectioning model (12 cadavers) using ROC analysis and Youden’s J thresholds. Across clinical cohorts, objective IVM abnormalities were uncommon. Prevalence increased when studies demonstrated adequate total C2–C7 motion, emphasizing the importance of patient effort. In cadavers, vertical instability metrics were most discriminative (AUC 0.96–0.97) with high sensitivity (0.89) and perfect specificity at optimal thresholds, whereas translation changed minimally with sectioning. These results support regression-based instability indices as promising candidates for standardized, physiology-guided cervical instability assessment. Full article

This study presents a finite element (FE) investigation of intervertebral disc (IVD) degeneration in the human lumbar spine (L1–L3 segment). The model, based on CT-derived geometry and isotropic hyperelastic representation of disc tissues, incorporates controlled simplifications, detailed in the limitations section. Degenerative changes were parametrically simulated across healthy, mild, moderate, and severe stages by reducing disc height (up to 60%), nucleus pulposus volume (up to 70%), and adjusting tissue stiffness to reflect dehydration and fibrosis. Displacement-controlled compressive loading was applied to assess von Mises stress distributions, reaction forces, and load transfer mechanisms. Results indicate significant load redistribution: annulus fibrosus stresses increased by up to 175% in severe degeneration, while nucleus pulposus stresses decreased by ~70%, indicating a diminished compressive load-bearing contribution of the nucleus. Model predictions were validated against cadaveric and in vivo data, confirming trends in intradiscal pressure (IDP) reductions (40–70%) and stress elevations. The parametric framework elucidates interactions between geometric and material changes, providing clinicians with insights into degeneration progression and guiding biomedical engineers in implant design and interventions. Full article

Muscle degeneration is the hallmark of muscular dystrophies—genetically heterogeneous disorders traditionally approached through the lens of molecular pathogenesis or symptomatic management in isolation. Here, we present a deliberately interdisciplinary synthesis that bridges molecular genetics, clinical phenotyping, and evidence-based orthopedic decision-making to address a significant critical gap: the lack of genotype-informed, function-oriented frameworks for musculoskeletal complications. We re-evaluate disease entities—not only by their molecular etiology (e.g., DMD, LMNA, DUX4 dysregulation), but through the prism of orthopedic manifestations as diagnostic gateways and therapeutic milestones. For instance, early rigid spine in LMNA-related dystrophy is not merely a sign of contracture, but a red flag demanding cardiac risk stratification before surgical planning, in alignment with current consensus. Similarly, scoliosis management in Duchenne muscular dystrophy is discussed through quantitative decision thresholds (Cobb angle ≥ 20–30°, FVC ≥ 30–35%) derived from long-term outcome studies, rather than general clinical recommendations. Critically, we confront challenges posed by disease-modifying therapies: patients now survive into their 30s and 40s, yet develop novel, therapy-exacerbated orthopedic phenotypes (e.g., steroid-induced osteoporosis, atypical spinal rigidity). Therefore, we argue that precision orthopedics—tailored surveillance, genotype-stratified intervention timing (e.g., D4Z4 repeat-guided monitoring in FSHD, and realistic functional goal-setting (e.g., scapular arthrodesis for overhead function)—should become the gold standard of care. For example, desminopathies may show marked phenotypic variability even within the same mutation. Our review thus serves not only as a molecular overview, but as a practical roadmap for neurologists, geneticists, orthopedic surgeons, and rehabilitation specialists seeking to translate genomic insights into durable functional outcomes. Full article

Spinal fusion remains a common surgical treatment for degenerative cervical spine pathology. By eliminating segmental motion, fusion alters spinal biomechanics and redistributes mechanical loads to adjacent levels. These changes contribute to adjacent segment degeneration (ASD). Motion-preserving spinal implants have been developed to address these limitations. Cervical disc arthroplasty (CDA) is the most widely used example. Such devices aim to maintain physiologic kinematics while preserving segmental stability. Their biomechanical behavior varies with implant design, material properties, and constraint characteristics. Previous research does not holistically compare fusion with motion-preserving treatments on the spine, resulting in an incomplete understanding of when motion-preserving devices should be considered in treatment over fusion constructs and which specific motion-preserving implants are most appropriate. This narrative review synthesizes experimental, computational, and clinical studies comparing rigid fusion constructs to motion-preserving technologies in the cervical spine. Emphasis is placed on segmental range of motion, load transmission, intradiscal pressure, facet joint forces, and adjacent-segment mechanics. By comparing effectiveness across motion-preserving treatments, alongside their effectiveness to fusion constructs, we found that CDA more closely preserves near-physiologic motion compared to fusion. Taken together, this review underscores the importance of biomechanics-informed implant design for guiding future innovation in spinal implant technologies. Full article

Intervertebral disc degeneration (IVDD) initiates a cascade of structural and biological changes that compromise mechanical function, often leading to chronic pain. While small animal models have provided insight into inflammatory and nociceptive mechanisms of IVDD, translational studies require large animal models that more closely replicate human spine anatomy and physiology. This study induced cervical disc degeneration via intradiscal chondroitinase ABC (ChABC) injection in a large animal model and evaluated the associated disc pathology and neuroinflammatory responses across IVDs and within spinal cord and dorsal root ganglia (DRG) tissues. Results confirmed structural degeneration at ChABC-injected levels and revealed additional evidence of adjacent segment degeneration. Neuroinflammatory analyses revealed innervation, via deposition of PGP9.5 and NFH, throughout both ChABC-injected and adjacent IVDs. Monocyte markers were significantly increased in ChABC-degenerated IVDs. Across experimental groups, the level of monocyte (Ly6C) and macrophage (CD68) markers correlated with worsened histological scores and with reduced mechanical integrity. Similarly, increased production of the neuropeptide, Substance P, in IVDs was significantly positively correlated with compromised IVD mechanical function. Finally, we observed elevated production of the microglia marker, Iba1, and Substance P production in the spinal cord, with similar trends in DRGs, in degenerative spines. By establishing quantitative relationships between disc pathology, immune responses, and neural activation, this work established possible disease-contributing neuroinflammatory activation and further validated a clinically relevant model for preclinical evaluation of regenerative and therapeutic strategies. Full article

Background/Objectives: Adult degenerative scoliosis (ADS) is a spinal disease causing pain and reduced mobility, often occurring with degenerative lumbar spinal stenosis (DLSS). While fusion stabilizes the spine, it has drawbacks like loss of motion and adjacent segment degeneration. Minimally invasive techniques, such as tubular unilateral laminotomy for bilateral decompression (tULBD), provide a less invasive alternative, but their impact on ADS with DLSS is underexplored. This study examines the short-term effects of navigated tULBD on radiological and clinical outcomes in this patient population. Methods: This retrospective single-center study analyzed patients aged ≥18 years with DLSS and ADS (Cobb angle ≥ 10°), with or without grade I spondylolisthesis, who underwent navigated tULBD between June 2019 and October 2022. Radiological parameters were assessed pre- and post-operatively using AI-powered FXA™ Version 1.33, Raylytic Software GmbH, Leipzig, Germany, while clinical outcomes were evaluated using the Oswestry Disability Index (ODI) and Numeric Rating Scale (NRS) for back and leg pain. Statistical analyses were conducted with R Studio. Results: This study included 20 patients (mean age 74.6 ± 7.6 years, body mass index [BMI] 26.08 ± 3.7 kg/m²), with a median follow-up of 2 months. Most underwent single-level decompression (45%), with a median of 2 surgical levels (IQR: 1–3). Radiological parameters showed no significant changes (p > 0.05). Clinically, the median NRS back improved from 5 (IQR: 3–9) preoperatively to 2 (IQR: 0–2) postoperatively (p = 0.009) and 1 (IQR: 0–4.5) at follow-up (p = 0.004). NRS leg scores dropped from 3.5 (IQR: 0–5) to 0 postoperatively and at follow-up (p = 0.02, p = 0.04). ODI improved from 37.8 (IQR: 29–42.5) preoperatively to 17.5 (IQR: 5–24) at follow-up (p = 0.04). There were no neurological complications. Conclusions: Navigated tULBD is a promising, minimally invasive option for mild ADS and DLSS. It provides significant pain and disability relief without adversely affecting stability and alignment. Long-term studies are needed to confirm durability and efficacy, particularly in severe cases. Full article