Spine conditions come with specialized terminology that can be difficult to navigate without a guide. This glossary covers the most common terms patients encounter when exploring non-surgical treatment options — including biologic disc repair and annular tear repair. Candidacy for any treatment is assessed individually, and outcomes vary by patient and condition.
Annulus Fibrosus
The annulus fibrosus is the tough, fibrous outer ring of an intervertebral disc. Composed of multiple layers of collagen fibers, its primary role is to contain the disc’s gel-like center (nucleus pulposus) and to provide structural stability and flexibility to the spine. When this outer ring develops tears — often due to injury, age, or repetitive stress — it can allow inflammatory chemicals from the nucleus to leak out, irritating nearby spinal nerves and contributing to chronic back pain. These annular tears are a common underlying cause of disc-related pain and may be addressed with treatments like intra-annular fibrin injection to promote healing and help restore disc integrity.
Nucleus Pulposus
The nucleus pulposus is the soft, gel-like core located in the center of each intervertebral disc. Rich in water content, this inner material acts as the primary shock absorber for the spine, distributing pressure evenly across the vertebrae during movement and weight-bearing activities. When the surrounding annulus fibrosus tears, the nucleus pulposus can push through — a process called herniation — potentially leading to pressure on spinal nerves. The chemicals within the nucleus pulposus can also be highly inflammatory if they contact nerves outside the disc, causing pain, numbness, or weakness in the back, arms, or legs.
Intervertebral Disc
Intervertebral discs are the specialized cushions located between the vertebrae (bones) of the spine, from the neck down to the lower back. These structures serve two main functions: absorbing shock during movement and allowing the flexibility that enables bending and twisting. Each disc consists of a tough outer layer called the annulus fibrosus and a soft, gel-like inner core known as the nucleus pulposus. Over time, discs can undergo degeneration, lose hydration, or suffer injuries like tears and herniations — leading to conditions that often result in chronic pain and limited mobility.
Foramen
The foramen, or neural foramen, refers to the small bony opening on each side of the spinal column through which spinal nerves exit the spine to branch out to various parts of the body. These nerves transmit sensation, movement, and vital functions. If a spinal disc bulges or herniates, or if bone spurs develop due to arthritis, these structures can narrow the foramen. This narrowing can compress or “pinch” the exiting spinal nerve, leading to symptoms such as pain, numbness, tingling, or weakness in the areas supplied by that nerve — often in the arms or legs.
Facet Joint
Facet joints are small, paired joints located at the back of each vertebra, connecting adjacent spinal bones. They guide and limit spinal movement, ensuring stability while allowing for flexion, extension, and rotation. Like other joints in the body, facet joints can develop arthritis (osteoarthritis) over time due to wear and tear, injury, or inflammation. When these joints become inflamed or damaged, they can be a significant source of back or neck pain that may worsen with certain movements. Pain from facet joints is distinct from disc-related pain, although both can contribute to overall spinal discomfort.
Annular Tear
An annular tear is a rip or fissure in the annulus fibrosus — the tough outer ring of an intervertebral disc. These tears can occur due to sudden injury, repetitive stress, or age-related degeneration. When the annulus tears, it weakens the disc’s structure and may allow inflammatory chemicals from the nucleus pulposus to leak out and irritate nearby spinal nerves. Unlike many other tissues, annular tears often struggle to heal on their own due to the disc’s limited blood supply. Treatments like intra-annular fibrin injection are specifically designed to address these persistent tears and support the body’s natural healing process.
Degenerative Disc Disease (DDD)
Despite its name, Degenerative Disc Disease (DDD) is not actually a disease but a condition where the intervertebral discs between your vertebrae break down over time. This process is a natural part of aging for many people, though for some it may lead to chronic pain. DDD involves discs losing hydration, height, and elasticity — making them less effective as shock absorbers. This degeneration can contribute to disc bulging, herniation, annular tears, or conditions like spinal stenosis. Our clinical team evaluates each patient’s specific disc presentation to determine whether regenerative treatments may help restore disc function, rather than simply managing symptoms.
Herniated Disc
A herniated disc occurs when the soft, gel-like nucleus pulposus pushes through a tear in the annulus fibrosus and extends outside its normal boundary. This extruded material can then press on nearby spinal nerves or the spinal cord, causing symptoms that may include sharp pain, numbness, tingling, or weakness in the area served by the affected nerve — often radiating into an arm or leg. Also referred to as a “ruptured disc” or “slipped disc,” herniations are a significant cause of chronic back and neck pain in many patients. Regenerative options like biologic disc repair may help seal the tear and reinforce the disc structure; candidacy is evaluated on a case-by-case basis.
Bulging Disc
A bulging disc is a common spinal condition where the intervertebral disc extends beyond its normal perimeter, but unlike a herniation, the outer annulus fibrosus remains intact, containing the nucleus pulposus. The disc essentially “bulges” circumferentially or in a localized area without a complete rupture of the outer layers. While generally less severe than a herniated disc, a bulging disc can still cause significant pain in many patients. This pain arises from the bulging material pressing on nearby spinal nerves, irritating surrounding tissues, or contributing to narrowing of the spinal canal or nerve root openings (foramen) — leading to symptoms like localized back pain, sciatica, or radiculopathy.
Sciatica
Sciatica is a specific type of nerve pain characterized by discomfort that radiates along the path of the sciatic nerve. This nerve originates from nerve roots in the lower back, travels through the buttock, and extends down the back of each leg. Sciatica typically affects only one side of the body and may manifest as a shooting pain, burning sensation, numbness, or tingling that extends from the lower back through the hip, buttock, and into the leg or foot. It is most often caused by a herniated disc, spinal stenosis, or bone spurs compressing part of the sciatic nerve.
Radiculopathy
Radiculopathy describes a collection of symptoms that occur when a spinal nerve root is compressed, inflamed, or damaged. This compression can result from various factors, including a herniated disc, bulging disc, bone spurs, spinal stenosis, or thickened ligaments. The symptoms of radiculopathy typically travel along the specific nerve’s pathway, often radiating away from the spine. Depending on the location, cervical radiculopathy affects the neck and arms — causing pain, numbness, or weakness — while lumbar radiculopathy impacts the lower back and legs, often presenting as sciatica or general leg pain and weakness. Identifying the exact nerve root involved is important to effective treatment planning.
Discogenic Pain
Discogenic pain refers specifically to pain that originates directly from a damaged or degenerated intervertebral disc itself, rather than from nerve root compression. This type of pain is often described as a deep, aching discomfort in the back, typically localized to the area of the affected disc. It may worsen with activities that increase pressure on the disc, such as prolonged sitting, bending, lifting, or twisting. Discogenic pain can occur even without a major herniation or nerve impingement, often stemming from inflammation within the disc or irritation of nerve endings in the outer annulus fibrosus due to tears. Fibrin disc treatment directly targets these damaged discs to address the underlying source of pain.
Spinal Stenosis
Spinal stenosis is a condition characterized by the narrowing of the spinal canal — the space that houses the spinal cord and nerve roots — or the narrowing of the nerve root openings (foramen). This narrowing can put pressure on the spinal cord and nerves, leading to symptoms such as pain, numbness, tingling, or weakness in the legs, arms, or back. The most common causes include degenerative changes like bulging discs, bone spurs (osteophytes), thickened ligaments, and arthritis of the facet joints. For a detailed overview of how this condition presents, see our guide on common spinal stenosis symptoms.
Failed Back Surgery Syndrome (FBSS)
Failed Back Surgery Syndrome (FBSS), also known as post-laminectomy syndrome, refers to chronic pain that persists or returns after one or more spine surgeries — particularly for lumbar disc problems. Despite undergoing surgery, patients with FBSS may continue to experience significant pain, sometimes worse than before their operation, or develop new pain in different areas. There are many possible contributing factors, including incomplete decompression, nerve damage, scar tissue formation, instability, or the original diagnosis not being fully addressed. Our clinical team offers non-surgical regenerative options that may address underlying disc pathology without further invasive procedures — though candidacy is evaluated individually.
Fibrin
Fibrin is a natural, insoluble protein that plays a critical role in the body’s healing and clotting processes. When tissue is injured, fibrin forms a mesh-like scaffold that helps stop bleeding and provides a framework for new cells to grow and repair the damaged area. In regenerative spine treatments, medical-grade fibrin is used for its adhesive and biological properties. In intra-annular fibrin injection specifically, it is carefully delivered into damaged intervertebral discs to help seal annular tears and provide a biological scaffold that may encourage the body’s natural healing mechanisms, supporting disc repair over time.
Regenerative Medicine
Regenerative medicine is an innovative field of healthcare focused on harnessing the body’s ability to heal, repair, and regenerate damaged tissues and organs. Rather than merely managing symptoms or surgically removing damaged parts, regenerative treatments aim to restore the structure and function of diseased or injured tissues. In spine care, this approach involves using biological substances — often derived from the patient’s own body, such as fibrin — to stimulate natural healing processes within the intervertebral discs, joints, and ligaments. Our clinical team specializes in biologic disc repair as a potential non-surgical alternative; outcomes vary by patient and condition.
Intradiscal Injection
An intradiscal injection is a medical procedure where substances are directly injected into the center of an intervertebral disc, allowing for targeted delivery of therapeutic agents precisely where they are needed. Unlike epidural injections that deliver medication around the nerves, intradiscal injections aim to treat the disc itself. Our clinical team uses this technique to perform advanced regenerative treatments such as biologic disc repair (fibrin disc treatment). By injecting fibrin directly into the disc, we may help seal annular tears, support healing, and potentially restore disc integrity — offering a non-surgical pathway for carefully selected patients with chronic discogenic pain.
For a deeper look at these conditions in context, we recommend our guide: A Comprehensive Guide to Lumbar Spine Conditions and Regenerative Disc Repair.
