Vascularization of the human intervertebral disc: A scoping review
Bibliographic record
Abstract
Intervertebral discs (IVDs) are often referred to as the largest avascular structures of the human body, yet a collective resource characterizing the vascularization of the IVD does not exist. To address this gap, the objective of this study was to conduct a comprehensive search of the literature to review and summarize current knowledge of the prevalence and localization of blood supply in human IVDs, with a scoping review. A comprehensive search of peer-reviewed publications on the topic of IVD vascularization in humans was conducted across six electronic databases: PubMed, EMBASE, MEDLINE, Scopus, Web of Science, and BIOSIS Previews. Studies of humans were included regardless of age, sex, ethnicity, and health status, with the exception of IVD herniation. Two independent reviewers screened titles and abstracts and full-texts according to eligibility criteria. The review was conducted and reported according to Preferred Reporting Items for Systematic Reviews Extension for Scoping Reviews guidelines. Our search yielded 3122 articles, with 22 articles meeting the inclusion criteria. The study samples ranged in age from fetal to >90 years and included both sexes, various health statuses, and used different methodologies (eg, histology, medical imaging, and gross dissection) to assess vasculature. Overall, consistent observations were that (a) the nucleus pulposus of the IVD is avascular throughout life, (b) both the cartilage endplates and annulus fibrosus receive considerable blood supply early in life that diminishes over the lifespan, and (c) vascular ingrowth into the cartilage endplates and inner layers of the annulus fibrosus is commonly associated with damaged or disrupted tissue, irrespective of age. Histology and immunohistochemistry are often used to report vascularization of the IVD. The body of the current literature suggests that the IVD should not be generalized as an avascular tissue. Instead, vascularization of the IVD differs based on the constituent tissues, their age, and state of degeneration or damage.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.009 | 0.043 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.005 | 0.004 |
| Bibliometrics | 0.021 | 0.017 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.005 | 0.003 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.003 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".