Navigating spine conditions and regenerative treatment options may feel overwhelming, especially when clinical terminology is unfamiliar. This patient-friendly glossary defines the core anatomical structures, common disc conditions, and biologic treatment concepts our clinical team uses every day—so you can approach your evaluation and care decisions from a position of knowledge. Individual candidacy is always assessed on a case-by-case basis; outcomes vary.

Spinal Anatomy

Vertebra

A vertebra is one of the individual bones that form the spinal column. The human spine contains 33 vertebrae stacked in sequence and separated by intervertebral discs. Vertebrae protect the spinal cord and nerve roots, support the body’s weight, and allow a wide range of motion. Regional groupings include 7 cervical (neck), 12 thoracic (mid-back), 5 lumbar (lower back), 5 fused sacral, and 4 fused coccygeal bones. Understanding how these segments are organized is foundational for interpreting any spinal diagnosis.

Intervertebral Disc

An intervertebral disc is a cushion-like structure positioned between adjacent vertebrae throughout the spinal column, from the cervical spine down to the lumbar region. Each disc absorbs shock, enables spinal flexibility, and distributes compressive loads evenly. Every disc has two distinct components: the annulus fibrosus (tough outer ring) and the nucleus pulposus (gel-like inner core). With age, injury, or cumulative stress, discs may develop annular tears, herniation, or degenerative changes—common root causes of chronic back and neck pain.

Annulus Fibrosus

The annulus fibrosus is the tough, multi-layered fibrous outer ring of an intervertebral disc. Composed of interwoven collagen fibers, it contains the nucleus pulposus and provides the disc with structural integrity under load. When these fibers sustain a rip or fissure—referred to as an annular tear—inflammatory chemicals from inside the disc may leak out and irritate nearby nerve tissue, often generating chronic discogenic pain. Because disc tissue has a limited blood supply, annular tears may not heal spontaneously in many patients, making targeted repair an important focus of biologic disc repair approaches. Learn more at our overview of annular tears as a root cause of back pain.

Nucleus Pulposus

The nucleus pulposus is the soft, highly hydrated gel-like core located within the annulus fibrosus. Rich in water-attracting proteoglycans, it provides the disc with its primary shock-absorbing capability, cushioning the vertebrae during everyday movement. When the surrounding annulus fibrosus sustains a tear, nuclear material may migrate toward spinal nerve roots, potentially triggering pain, inflammation, numbness, or limb weakness depending on the affected spinal level. Preserving the integrity of the nucleus pulposus through a healthy outer annulus is central to long-term disc health.

Foramen

The foramen (plural: foramina) refers to the natural bony openings in and around the spinal column through which nerve roots exit to travel to the rest of the body. The intervertebral foramen, located between adjacent vertebrae, is the most clinically relevant passageway for disc-related conditions. When disc herniation, bone spurs, or thickened ligaments narrow these openings—a process called foraminal stenosis—the exiting nerve root may become compressed, producing symptoms such as pain, numbness, tingling, or weakness in the arms or legs.

Common Disc Conditions

Annular Tear

An annular tear is a rip or fissure in the annulus fibrosus, the strong outer layer of an intervertebral disc. These tears are a frequent and clinically significant source of chronic discogenic pain. Inflammatory mediators inside the disc can leak through the tear, sensitizing nearby nerve fibers and triggering persistent pain even without frank nerve compression. Because discs receive minimal direct blood supply, annular tears are often slow to heal on their own. Identifying and addressing these tears is central to our approach at Valor Spine; intra-annular fibrin injection is one option our clinical team evaluates for appropriate candidates. For a deeper dive, see annular tear causing chronic lower back pain.

Expert Take

Annular tears are among the most under-diagnosed causes of axial back pain. Standard MRI may underestimate their presence, which is why a detailed clinical evaluation and, in some cases, a provocative discographic study may be warranted before finalizing a treatment plan. Candidacy for repair procedures is determined individually.

Degenerative Disc Disease (DDD)

Despite its name, degenerative disc disease (DDD) is a condition rather than a true disease—it describes the progressive structural breakdown of one or more intervertebral discs, often associated with aging, cumulative mechanical stress, or prior injury. DDD involves a loss of disc height, reduced hydration within the nucleus pulposus, and the gradual development of annular tears. Some individuals with imaging findings of DDD experience little or no discomfort; for others, DDD contributes to chronic back or neck pain, stiffness, and nerve compression. Our clinical team evaluates each presentation individually to determine which regenerative or conservative options may be appropriate. See also: DDD causes and when to seek alternatives.

Herniated Disc

A herniated disc occurs when the nucleus pulposus—the soft inner core—protrudes through a tear or weakness in the annulus fibrosus, potentially encroaching on adjacent spinal nerves or the spinal cord. Also described as a ruptured or slipped disc, a herniation is a common contributor to radicular pain, sciatica, and sensory or motor changes in the extremities. The severity of symptoms depends on the size and direction of the herniation as well as the patient’s individual anatomy. Regenerative approaches focused on stabilizing and repairing the underlying disc may be evaluated for appropriate candidates. For related reading, visit bulging disc vs herniated disc: understanding your pain.

Sciatica

Sciatica describes radiating pain that follows the distribution of the sciatic nerve—the longest nerve in the body—from the lower back through the buttock and down one leg. Characteristic features include sharp, shooting pain, burning, numbness, or tingling along the nerve pathway. Sciatica is most often caused by compression or irritation of a lumbar nerve root, frequently due to a herniated disc, spinal stenosis, or bone spurs. Addressing the underlying disc pathology, rather than only managing symptoms, is a focus of biologic disc repair in qualifying candidates. Learn more about common misconceptions at 10 myths about sciatica and non-surgical relief.

Radiculopathy

Radiculopathy describes the constellation of symptoms that arise when a spinal nerve root is compressed, inflamed, or injured. Pain, numbness, tingling, or weakness radiates along the specific nerve’s distribution: cervical radiculopathy typically produces arm and hand symptoms, while lumbar radiculopathy produces leg and foot symptoms. Common causes include herniated discs, foraminal stenosis, and osteophytes (bone spurs). Our clinical team works to identify the precise anatomical source of nerve compression before recommending any intervention, as treatment candidacy varies by individual presentation.

Diagnostic Tools

Annulargram (Discogram)

An annulargram—also called a discogram or discography—is a specialized provocative diagnostic procedure used to confirm the presence of annular tears and to determine whether a specific disc is generating a patient’s pain. Under fluoroscopic (live X-ray) guidance, a contrast agent is carefully injected into the center of the suspected disc. If dye leaks into the annulus, a tear is visualized; if the injection reproduces the patient’s familiar pain pattern (concordant pain), that disc is identified as a symptomatic pain source. This information may help our clinical team determine whether a patient is an appropriate candidate for fibrin disc treatment or other targeted interventions. Candidacy is always evaluated individually. See also: glossary of diagnostic imaging and evaluation terms.

Regenerative & Biologic Treatment Concepts

Regenerative Medicine

Regenerative medicine is a field of care focused on stimulating or augmenting the body’s intrinsic healing mechanisms to restore the structure and function of damaged tissues. In spine care, regenerative approaches aim to address the root cause of disc pathology—such as annular tears or disc degeneration—rather than relying solely on symptom management or structural removal. Valor Spine specializes in regenerative spine care, including biologic disc repair procedures designed to support the disc’s own healing environment. Outcomes and candidacy vary by individual; not every patient is a suitable candidate for regenerative procedures. For a broader overview, see 5 non-surgical disc treatments for chronic back pain.

Fibrin

Fibrin is a naturally occurring structural protein central to the body’s wound-healing cascade. When tissue is injured, fibrin polymerizes into a mesh-like scaffold that helps arrest bleeding and provides a matrix for cellular repair and tissue regeneration. In the context of biologic disc repair, concentrated fibrin is used as a biologic sealant delivered directly into a damaged intervertebral disc. The fibrin scaffold may support the sealing of annular tears and create a favorable environment for tissue healing within the disc. This approach leverages materials compatible with the body’s own biology, and candidacy for the fibrin procedure is assessed individually.

Intra-Annular Fibrin Injection

Intra-annular fibrin injection—also referred to as the fibrin procedure or fibrin disc treatment—is a minimally invasive biologic disc repair technique in which concentrated fibrin is delivered precisely into or around an annular tear under fluoroscopic guidance. The goal is to seal the tear, reduce the leakage of inflammatory disc contents, and create a supportive environment for disc healing. Unlike epidural steroid injections that target the space around the nerve, this approach treats the disc structure directly. Our clinical team evaluates each patient’s imaging, symptoms, and history to determine whether intra-annular fibrin injection may be an appropriate option. For candidacy information, visit am I a candidate for biologic disc repair?

Intradiscal Injection

An intradiscal injection is a procedure in which a therapeutic substance is delivered directly into the interior of an intervertebral disc under image guidance, most commonly fluoroscopy. This approach targets the disc itself rather than the surrounding epidural space, making it suitable for conditions that originate within the disc—such as annular tears or internal disc disruption. Intra-annular fibrin injection is one type of intradiscal procedure. As with any intervention, patient selection and precise technique are critical variables that our clinical team considers on a case-by-case basis.

Expert Take

Precise image guidance is essential for intradiscal procedures. Fluoroscopic confirmation of needle placement helps ensure the therapeutic agent reaches the intended target within the disc. Each treatment plan is individualized; our clinical team reviews imaging, symptom history, and prior treatment responses before recommending any intradiscal approach.

Biologic Disc Repair

Biologic disc repair is an umbrella term for minimally invasive procedures that use biological or biocompatible materials—such as fibrin—to restore disc structure and promote healing from within. The approach contrasts with traditional surgical interventions (such as discectomy or spinal fusion) by preserving disc tissue rather than removing or immobilizing it. Candidates for biologic disc repair are evaluated based on their specific disc pathology, symptom profile, prior treatment history, and overall health. Outcomes vary; many patients who are appropriate candidates report meaningful improvements, while recovery timelines and results differ by individual. For a comparison with surgical options, see biologic disc repair vs. traditional spine surgery.

Post-Surgical Considerations

Failed Back Surgery Syndrome (FBSS)

Failed back surgery syndrome (FBSS) describes chronic, persistent pain that continues or recurs after one or more spine surgeries, even when the original surgical objectives appeared to have been met. FBSS can stem from multiple factors, including scar tissue formation, adjacent segment disease, persistent nerve compression, or an incomplete identification of the original pain source. For patients experiencing FBSS, regenerative options such as biologic disc repair may be worth evaluating to address underlying disc damage that prior surgery did not fully resolve. Candidacy depends on the individual’s specific anatomy, surgical history, and current disc status. See also: after failed back surgery: is biologic disc repair your next step?

Expert Take

Patients with FBSS often benefit from a comprehensive re-evaluation that includes updated imaging and a detailed symptom history. In some cases, annular tears that were not identified or addressed during the initial surgical episode may be contributing to ongoing pain. Regenerative options may be appropriate for select candidates following thorough assessment; individual outcomes vary.

Frequently Asked Questions

What is the difference between an annular tear and a herniated disc?

An annular tear is a fissure confined to the outer fibrous ring (annulus fibrosus) of the disc, whereas a herniated disc involves the inner nucleus pulposus actually pushing through the annulus and into the spinal canal or foramina. Both conditions may cause significant pain, but they represent different stages and patterns of disc injury. Treatment options differ accordingly, and candidacy for specific interventions is evaluated individually.

Can annular tears heal on their own?

Because intervertebral discs receive a limited direct blood supply, spontaneous healing of annular tears is often slow and incomplete in many patients. Conservative measures such as physical therapy, activity modification, and anti-inflammatory care may help manage symptoms in some individuals; however, structural repair of the tear itself may require a targeted biologic approach for those who do not improve adequately. Each case is assessed on its own merits.

What makes fibrin disc treatment different from an epidural steroid injection?

Epidural steroid injections deliver anti-inflammatory medication into the space surrounding the spinal nerves to reduce inflammation and temporarily relieve symptoms. They do not address the structural disc defect itself. In contrast, intra-annular fibrin injection targets the disc directly, aiming to seal the annular tear and support the disc’s healing environment. While epidurals may offer short-term symptom relief in some patients, fibrin disc treatment is designed to address the underlying structural source of discogenic pain. Outcomes and suitability differ by individual.

Who is a candidate for intra-annular fibrin injection?

Candidacy is determined through a thorough clinical evaluation that typically includes a review of symptoms, prior treatment history, and advanced imaging. In some cases, a provocative discogram (annulargram) may be used to confirm the symptomatic disc level. Not every patient with an annular tear or disc degeneration is an appropriate candidate; our clinical team evaluates each presentation individually to determine which options may be suitable.

What is the role of regenerative medicine in spine care compared with spinal fusion?

Spinal fusion immobilizes a painful spinal segment by permanently connecting adjacent vertebrae, which eliminates motion at that level and may transfer stress to neighboring discs over time. Regenerative approaches, by contrast, aim to restore disc tissue function and reduce pain while preserving natural spinal motion. Neither approach is universally appropriate; the right option depends on the patient’s specific pathology, overall spine stability, prior treatments, and individual goals. Candidates for either pathway are evaluated on a case-by-case basis. For further reading, visit 7 best spinal fusion alternatives: a patient’s guide.