Background: Lumbar spondylolysis is commonly evaluated initially with lumbar radiography, but radiographs may miss pars interarticularis defects, particularly at L5. This study aimed to characterize radiographic and morphological features associated with bilateral L5 spondylolysis and to develop and externally evaluate an X-ray-based screening nomogram for radiographic risk stratification. Methods: This cross-sectional study included patients who underwent lumbar radiography and computed tomography (CT) between 2018 and 2025. Patients with CT-confirmed bilateral L5 spondylolysis were compared with controls without spondylolysis. Radiographic parameters and CT-based morphological features were measured and analyzed separately, and interobserver reliability was assessed. Propensity score matching (PSM) (1:1) was used to balance baseline characteristics. Factors associated with L5 spondylolysis were identified using multivariable logistic regression, and an X-ray-only nomogram was constructed using significant radiographic variables. Model performance in the development cohort was assessed using discrimination, calibration, decision curve analysis (DCA), and clinical impact curves (CICs) with internal bootstrap validation. External validation applied the original development-cohort coefficients without refitting and primarily assessed discrimination in an independent dataset. Results: After PSM, 114 patients were included in the development cohort, with 57 patients in each group. Compared with controls, patients with L5 spondylolysis had larger sacral slope (SS), L5 lamina inclination angle (L5 LIA), and pedicle internal inclination angle, as well as smaller sacral inclination (SI) and L5 lumbar index. Multivariable analysis identified smaller SI, smaller L5 lumbar index, larger SS, larger L5 LIA, and larger pedicle internal inclination angle as factors independently associated with L5 spondylolysis. L5 LIA showed the strongest individual diagnostic performance (area under the curve [AUC] = 0.879; 95% CI, 0.813–0.944). The X-ray screening model incorporating the L5 lumbar index, SI, SS, and L5 LIA achieved excellent discrimination in the development cohort (AUC = 0.916; bootstrap-corrected concordance index = 0.911) and maintained strong discrimination in the external validation dataset when the development-cohort coefficients were applied without refitting (AUC/C-index = 0.949; 95% CI, 0.922–0.977). Conclusions: An X-ray-based nomogram incorporating key sagittal alignment and morphological parameters showed strong diagnostic discrimination for bilateral L5 spondylolysis in both the development cohort and the external validation dataset. This model should be interpreted as a radiographic screening and risk-stratification aid rather than a tool for prospective prognosis. CT-based analysis also showed that patients with L5 spondylolysis had a larger pedicle internal inclination angle, a morphological difference with potential relevance to preoperative planning.
Unilateral biportal endoscopy (UBE) has emerged as an effective alternative to open surgery for the treatment of adjacent segment pathology (ASP) -induced lumbar spinal stenosis (LSS), offering advantages such as minimal invasiveness and accelerated recovery. An 84-year-old female patient who underwent lumbar 4–5 (L4–L5) vertebral fusion 13 years ago presented with intermittent claudication over the past year; visual analog scale (VAS) score was 9. She was diagnosed with ASP and LSS. The patient was treated with UBE surgery at our institution. During spinal endoscopic surgery, when dural tears or partial dural defects are encountered, intact but dissociated cauda equina nerve roots can be observed floating loosely within the spinal canal intraoperatively—a phenomenon we termed the cauda equina floating sign (CEFS). After adequate decompression of the spinal canal, a medical absorbable collagen membrane was applied to cover and protect the cauda equina. The procedure was successfully completed with an estimated blood loss of 50 mL and an operative time of 2.5 h. Postoperatively, the patient’s lower limb symptoms were significantly relieved. She was able to ambulate on postoperative day 5 and was discharged on day 8. Her VAS score was 3. At the 6-month follow-up, her symptoms had substantially improved, and she had resumed normal daily activities. Magnetic resonance imaging at the 1-year postoperative follow-up demonstrated adequate spinal canal decompression. The patient’s low back and lower limb pain were also significantly relieved, with a VAS score of 1. The combination of UBE and a medical absorbable collagen membrane may represent an effective therapeutic strategy for CEFS and could potentially reduce the risk of cerebrospinal fluid leakage.
The intervertebral disc (IVD) is a complex structure vital for spinal function, whose degeneration is a leading cause of low back pain. While research has traditionally focused on the nucleus pulposus (NP) and annulus fibrosus (AF), the cartilaginous endplate (CEP)—the critical interface between the disc and vertebral body—has been historically underappreciated and often anatomically conflated with the adjacent bony endplate (BEP). This review aims to systematically synthesize current knowledge to clarify the unique attributes of the CEP and establish its role as the primary initiator of the IVD degenerative cascade. We first elucidate the fundamental biology of the CEP, distinguishing its distinct histological identity and dual “mechanical and nutritional” functions, which are essential for disc homeostasis. Subsequently, we detail the morphological progression and functional consequences of CEP degeneration, emphasizing its strong clinical relevance to discogenic pain and treatment outcomes. A core section critically examines the mechanisms of degeneration, focusing on the traditional “nutrient deprivation hypothesis” linked to reduced CEP permeability and a newer perspective highlighting the paramount importance of CEP–BEP interfacial integrity as a potential initiator of pathological cascades. We then evaluate the characteristics and limitations of various animal models used in CEP research, providing guidance for model selection based on specific scientific questions. Furthermore, we summarize recent advances in the molecular and cellular mechanisms driving CEP degeneration, including dysregulated matrix metabolism, aberrant mechanotransduction, oxidative stress, and epigenetic regulation. In conclusion, this review positions the CEP not as a passive structure but as an active hub whose health dictates IVD fate. Recognizing CEP degeneration as a pivotal driver offers significant translational relevance, shifting the clinical focus toward early-stage diagnosis and disease-modifying therapeutic strategies. Future interventions targeting CEP matrix health and interfacial integrity hold the potential to halt or reverse disc degeneration at its source, providing a paradigm shift in the management of chronic low back pain.
Spinal deformity is a relatively common and serious disease. Due to the complexity of the disease and the risk of treatment, it is important to develop effective assessment, screening, treatment, and prediction tools. As a new type of productivity, the application of artificial intelligence (AI) in the medical field is expanding and deepening, bringing revolutionary changes to clinical work. AI has changed the whole process of spinal deformity from early evaluation and screening to surgical decision-making and assistance by improving diagnostic accuracy, work efficiency, and personalized diagnosis and treatment. Through automated standardized imaging parameter measurements, AI has significantly enhanced diagnostic efficiency and consistency. Combined with cluster analysis and multimodal data, AI has strengthened the objectivity and scientific rigor of spinal deformity classification. Moreover, AI’s potential in surgical planning and risk prediction is increasingly evident, driving the development of personalized treatment. AI-integrated robotic navigation systems not only improve surgical outcomes but also accelerate physicians’ professional growth. However, key bottlenecks in clinical AI applications remain data universality, algorithmic interpretability, and ethical regulatory constraints. Future research should focus on high-quality, multicenter, long-term clinical validation studies to provide robust evidence for AI’s effectiveness and safety. Accelerating the development of explainable AI will help demystify decision-making processes and build clinical trust. Improving regulatory frameworks and standardized supervision mechanisms is crucial for delivering tangible patient benefits. AI’s vast potential lies in ushering spinal deformity management into a new era of precision medicine and data-driven approaches, becoming an indispensable force in spinal deformity prevention and treatment.
Chordomas are rare malignant tumors arising from remnants of the notochord, accounting for approximately 1% to 4% of all skeletal malignancies. These tumors are typically slow-growing and most commonly involve the sacrum, skull base, and spine. Their management is particularly challenging because of their proximity to critical neural and vascular structures. Although chordomas have a relatively low risk of distant metastasis, they are characterized by a high rate of local recurrence, necessitating aggressive, carefully planned treatment strategies. A narrative review of the literature was conducted to evaluate current approaches to the management of spinal chordomas, with a particular focus on surgical techniques and the role of adjuvant radiotherapy (RT). Relevant studies were identified through electronic database searches, including MEDLINE, Scopus, ProQuest, and Google Scholar. The selected literature was analyzed to assess surgical approaches, associated complications, oncological and functional outcomes, and the evolving role of RT in treatment. Surgical resection remains the cornerstone of treatment, with en bloc excision and negative margins as the gold standard. However, achieving complete resection, especially in the cervical spine, is often technically demanding due to anatomical constraints. For sacral chordomas, sacrectomy is frequently employed, while en bloc spondylectomy is considered for thoracolumbar lesions. Despite aggressive surgical strategies, complete tumor removal is not always feasible. In such cases, advancements in RT, particularly proton beam therapy and carbon ion therapy, have emerged as promising adjuncts. These modalities offer improved dose delivery while sparing surrounding critical structures. Nevertheless, the overall benefit of adjuvant RT remains a subject of ongoing debate in the literature. Postoperative complications are not uncommon and may include wound infections, neurological deficits, and mechanical instability, underscoring the complexity of managing these tumors. Given these challenges, a multidisciplinary approach involving neurosurgeons, orthopedic surgeons, radiation oncologists, and rehabilitation specialists is essential. In conclusion, the management of spinal chordomas requires an individualized and balanced approach that considers surgical feasibility, preservation of neurological function, and long-term disease control. While en bloc resection remains the mainstay of treatment, emerging RT techniques may enhance outcomes in selected patients. A coordinated multidisciplinary strategy is crucial to improving both prognosis and quality of life.
