Navigating spine care becomes easier when patients understand the terminology their clinical team uses. This glossary defines key anatomical structures, common disc conditions, and regenerative treatment concepts relevant to pain management and rehabilitation. Individual candidacy and treatment outcomes vary — our clinical team evaluates each patient’s imaging, symptoms, and history before recommending any approach.

Annulus Fibrosus

The annulus fibrosus is the tough, fibrous outer ring of an intervertebral disc. Composed of multiple layers of collagen fibers, it encases the gel-like nucleus pulposus within, providing structural integrity and stability to the spine. When healthy, the annulus fibrosus allows the spine to withstand significant pressure and movement. Tears in this outer ring — often caused by injury or degeneration — are a common source of chronic back pain. These annular tears can allow inflammatory substances to leak out, irritating nearby nerves, and may lead to more severe disc problems if unaddressed. Our clinical team focuses on repairing these tears to support disc health.

Nucleus Pulposus

The nucleus pulposus is the soft, gel-like center of an intervertebral disc. Rich in water content, its primary function is to act as a shock absorber, distributing pressure evenly across the vertebrae during movement and weight-bearing activities. It works in conjunction with the annulus fibrosus to provide both flexibility and cushioning to the spinal column. When the annulus fibrosus is compromised by a tear, the nucleus pulposus may bulge or herniate — pushing through the tear and potentially compressing adjacent spinal nerves. Understanding the nucleus pulposus is key to comprehending disc injuries and how treatments aim to support the disc’s natural function.

Intervertebral Disc

An intervertebral disc is a cushion-like structure located between each vertebra in the spinal column, from the neck down to the sacrum. These discs serve as crucial shock absorbers, protecting the vertebrae from impact, and also facilitate spinal flexibility across a wide range of motion. Each disc consists of two main parts: the tough outer annulus fibrosus and the gel-like inner nucleus pulposus. Over time, or due to injury, discs can degenerate, lose hydration, develop tears, or herniate — leading to significant pain and reduced mobility. Our clinical team specializes in non-surgical treatments aimed at repairing and supporting damaged intervertebral discs in appropriate candidates.

Annular Tear

An annular tear is a rip or fissure in the annulus fibrosus, the strong outer layer of an intervertebral disc. These tears range from small fissures to larger radial tears that extend deeper into the disc. Annular tears are a significant source of chronic back pain because they allow inflammatory chemicals from the nucleus pulposus to leak out and irritate nearby spinal nerves. Unlike many tissues, the annulus fibrosus often struggles to heal on its own due to the disc’s limited blood supply. Our advanced biologic disc repair treatments — including intra-annular fibrin injection — are designed to seal these tears and promote the disc’s natural healing process in appropriate candidates.

Degenerative Disc Disease (DDD)

Degenerative Disc Disease (DDD) refers to the natural, progressive breakdown of spinal discs over time. Despite the name, it is a condition rather than a disease, and it represents a normal part of aging. DDD is characterized by discs losing height, hydration, and elasticity, making them less effective at cushioning and absorbing shock. While many people with DDD experience no symptoms, others develop chronic pain, stiffness, and related conditions such as bulging discs, herniated discs, or spinal stenosis. Our clinical team offers treatments that may help mitigate the effects of DDD by promoting disc repair and regeneration — candidacy is evaluated on an individual basis.

Herniated Disc

A herniated disc occurs when the nucleus pulposus — the gel-like center of a spinal disc — pushes through a tear in the outer annulus fibrosus. This extruded disc material can press on nearby spinal nerves, producing symptoms such as sharp pain, numbness, tingling, or weakness in the arms or legs depending on the herniation’s location. Often called a “ruptured disc” or “slipped disc,” a herniation differs from a bulging disc in that it involves a breach of the outer annulus. Our non-surgical approaches aim to address the underlying annular tears that allow discs to herniate, supporting healing and reducing nerve compression in eligible patients.

Bulging Disc

A bulging disc is a common spine condition where the intervertebral disc extends beyond its normal boundary, but the outer annulus fibrosus remains intact without a full tear. The disc material spreads outward, creating a bulge that may press on nearby nerves or the spinal canal. While a bulging disc can be asymptomatic, it can cause pain, numbness, or weakness when it irritates or compresses a nerve root. It differs from a herniated disc, where the nucleus pulposus has broken through the annulus. Our treatments aim to support disc integrity and reduce pressure in candidates where this approach is clinically appropriate.

Sciatica

Sciatica is a type of pain that radiates along the path of the sciatic nerve — the longest nerve in the body, running from the lower back through the buttock and down the back of each leg. It typically affects only one side of the body and is often caused by compression or irritation of the nerve roots that form the sciatic nerve, most commonly due to a herniated disc, bone spur, or spinal stenosis in the lower back. Symptoms may include shooting pain, numbness, tingling, or muscle weakness. Our clinical team focuses on addressing root causes of nerve compression — such as repairing annular tears that contribute to disc herniation — to help relieve sciatic symptoms in appropriate candidates.

Radiculopathy

Radiculopathy describes a condition where a nerve root in the spine becomes pinched, compressed, or inflamed, causing symptoms that radiate along the nerve’s pathway — including pain, numbness, tingling, or weakness. Depending on the location, different areas of the body are affected: cervical radiculopathy impacts the neck and arms, while lumbar radiculopathy affects the lower back and legs (commonly called sciatica). Common causes include herniated discs, bone spurs, and spinal stenosis. Our non-surgical interventions, by supporting disc health and reducing nerve compression, may help alleviate radiculopathy symptoms in eligible patients — outcomes vary by case.

Discogenic Pain

Discogenic pain refers specifically to pain that originates from a damaged intervertebral disc itself, rather than from nerve compression caused by a disc problem. This type of pain is often a deep, aching discomfort in the lower back that may worsen with sitting, bending, lifting, or coughing. It is typically caused by internal disc disruption — often due to an annular tear that allows inflammatory chemicals to irritate pain receptors within the disc. Diagnosing discogenic pain can be challenging but is crucial for effective treatment planning. Our clinical team’s expertise in biologic disc repair directly addresses the source of discogenic pain by sealing annular tears and supporting disc structure repair in appropriate candidates.

Fibrin

Fibrin is a natural protein found in blood that plays a crucial role in the body’s healing and clotting processes. When tissue is damaged, fibrin forms a mesh-like scaffold that helps stop bleeding and provides a framework for new cells to grow and repair the injury. In regenerative disc treatment, fibrin is injected into damaged intervertebral discs to seal annular tears. It acts as a biologic sealant and scaffold, encouraging the disc’s own cells to support repair of torn tissue — with the goal of restoring disc integrity. Our clinical team harnesses fibrin’s natural properties to support healing in patients who are candidates for this approach.

Intra-annular Fibrin Injection

Intra-annular fibrin injection is a minimally invasive treatment for chronic back pain caused by annular tears and degenerative disc disease. The procedure involves injecting a specially prepared fibrin biologic directly into the damaged annulus fibrosus of an intervertebral disc. The fibrin acts as a natural sealant for annular tears and provides a scaffold, encouraging the body’s healing mechanisms to support disc tissue repair. Treatment aims to restore the disc’s structural integrity, prevent further leakage of inflammatory mediators, and reduce pain by addressing the root cause of disc pathology — offering a regenerative alternative to traditional surgical approaches for appropriate candidates.

Regenerative Medicine

Regenerative medicine is an innovative field focused on developing treatments that stimulate the body’s natural ability to heal, repair, and replace damaged or diseased tissues and organs. In spine care, regenerative medicine seeks to support disc repair by promoting the growth of healthy cells and tissues within intervertebral discs. Rather than managing symptoms alone or removing damaged parts, regenerative treatments aim to support restoration of the disc’s structure and function over time. Our clinical team applies regenerative medicine principles — including biologic disc repair — to offer non-surgical solutions for chronic spine pain in eligible patients.

Annulargram

An annulargram, also known as a discogram or provocative discography, is a specialized diagnostic procedure used to identify tears in the annulus fibrosus and confirm whether a specific disc is the source of a patient’s back pain. During the procedure, a small amount of contrast dye is injected directly into the intervertebral disc under fluoroscopic (live X-ray) guidance. The dye helps visualize tears or damage within the annulus that may not appear clearly on an MRI. If the injection reproduces the patient’s typical pain, it suggests that particular disc may be pain-generating. This diagnostic tool is important for evaluating candidacy for biologic disc repair treatments such as intra-annular fibrin injection.

Failed Back Surgery Syndrome (FBSS)

Failed Back Surgery Syndrome (FBSS) is a term used to describe chronic pain that persists or recurs after one or more surgical procedures on the spine — often performed for conditions like disc herniation or spinal stenosis. Despite surgery, patients with FBSS continue to experience significant pain, sometimes worse than before the procedure. FBSS can result from various factors, including persistent nerve compression, scar tissue formation, or adjacent segment disease. For patients struggling with FBSS, traditional surgical options may no longer be viable or desirable. Our clinical team offers non-surgical, regenerative treatments that may provide an alternative pathway — candidacy is evaluated individually based on imaging and clinical history.

For related definitions, we recommend: Key Terms in Spine Anatomy Relevant to Disc Conditions