What Is Adjacent Segment Disease?

Adjacent segment disease (ASD) is accelerated degeneration of the spinal discs and joints immediately above or below a prior surgical fusion. The fused segment transfers mechanical stress to neighboring levels, speeding their breakdown. It develops in a subset of fusion patients within 5–10 years of surgery and is among the leading causes of revision surgery — lumbar fusion revision rates exceed 20% within 10 years, individual outcomes vary.

For patients who have had spinal fusion and are now experiencing new or worsening back or leg pain, ASD is one of the first conditions a spine specialist will evaluate. Understanding what it is — and why it happens — is essential before deciding whether a second surgery is the right next step. This article explains the definition, the biomechanics, how ASD is diagnosed, what treatment options exist, and the questions worth asking your care team.

What Does Adjacent Segment Disease Actually Mean?

Adjacent segment disease describes pathological changes — disc degeneration, facet arthritis, listhesis, herniation, or stenosis — at the spinal level immediately next to a fused segment. The key word is disease: ASD is not simply normal aging. It is an accelerated process driven by altered spinal mechanics.

Two related terms appear in the clinical literature and are worth distinguishing:

• Adjacent segment degeneration (ASDeg): Radiographic changes visible on MRI or CT that are not yet producing symptoms. These changes are common; studies find imaging evidence in a substantial proportion of fusion patients within five years.
• Adjacent segment disease (ASD): The symptomatic subset — patients who have radiographic changes and new or worsening clinical symptoms attributable to the adjacent level.

The distinction matters clinically. Many fusion patients have some radiographic adjacent-level changes; far fewer have symptomatic ASD that warrants further intervention.

How Does Adjacent Segment Disease Develop?

The spine is a kinetic chain. Each vertebral level contributes a share of flexion, extension, and rotation. When a surgeon fuses one or more levels with hardware and bone graft, motion at that segment is permanently eliminated. The spine compensates by distributing that lost motion to the segments above and below the fusion — primarily to the adjacent levels.

This redistribution produces three compounding effects:

1. Increased range of motion at adjacent levels: The adjacent disc and facet joints move through a larger arc with each step, bend, and lift than they would in an unfused spine. Over years, this cumulative over-motion accelerates wear.
2. Elevated intradiscal pressure: Biomechanical studies demonstrate measurably higher pressure in the disc immediately adjacent to a fusion construct during routine loading tasks.
3. Altered facet joint loading: The facet joints at the adjacent level bear greater compressive and shear forces, accelerating arthritic change and contributing to foraminal narrowing over time.

In susceptible patients, a disc that was marginally healthy before fusion — with some annular disruption or early dehydration — can progress to symptomatic herniation, stenosis, or instability within years rather than decades.

Why Does Adjacent Segment Disease Lead to Revision Surgery?

ASD matters because its conventional treatment trajectory often leads toward another fusion — extending the construct to the adjacent level — which shifts the mechanical stress problem one level higher or lower, potentially repeating the cycle.

The data are sobering. Back surgery carries roughly a 40% failure rate as measured by Failed Back Surgery Syndrome outcomes in the peer-reviewed literature, and revision surgery rates can exceed 20% within 10 years of lumbar fusion. A meaningful share of those revisions involve adjacent segment pathology. Individual outcomes vary.

Nearly 1 in 5 patients told they need spine surgery choose not to have it. For patients facing an ASD diagnosis, a growing body of research examines whether structural interventions at the disc level — specifically targeting annular tears — can stabilize adjacent-level degeneration before another fusion becomes necessary.

For a deeper look at what happens when fusion does not achieve lasting relief, see: What Is Failed Back Surgery Syndrome? Causes, Symptoms, and Recovery Options.

What Are the Risk Factors for Adjacent Segment Disease?

Not every fusion patient develops symptomatic ASD. Several factors increase the likelihood that adjacent-level degeneration will become clinically significant:

How Is Adjacent Segment Disease Diagnosed?

Diagnosis of ASD requires correlation between imaging findings and symptoms — imaging changes alone are not sufficient. The evaluation typically includes:

• MRI: The primary tool for visualizing disc degeneration, herniation, canal stenosis, and foraminal narrowing at the adjacent level. T2-weighted sequences show disc hydration and annular integrity.
• Standing X-ray: Assesses alignment, sagittal balance, and signs of instability such as listhesis at the adjacent level under axial load.
• CT scan: Useful for evaluating bone changes, facet arthritis, and fusion hardware integrity when MRI is equivocal or the patient has implanted hardware that limits MRI quality.
• Annulogram: An imaging-guided diagnostic procedure that injects contrast dye into each disc under fluoroscopy. When dye leaks through a tear, the specific annular defects are confirmed. For patients with adjacent-level disc pain, an annulogram identifies whether structural disc damage — not just degeneration — is present and where.
• Clinical examination: Neurological testing, pain pattern assessment, and functional evaluation remain essential. A clinical evaluation is the only way to know for certain whether ASD is the source of a patient’s symptoms.

What Are the Treatment Options for Adjacent Segment Disease?

Treatment depends on the severity of symptoms, the degree of structural compromise at the adjacent level, and the patient’s overall health and goals. The options range from conservative care to surgical revision.

Conservative and Interventional Non-Surgical Options

• Physical therapy: Targeted to improve core stability, sagittal alignment, and load distribution across remaining mobile segments. Effective for mild-to-moderate ASD without neurological compromise.
• Epidural steroid injections: Address acute inflammatory flares but an AAFP systematic review found them not effective for chronic low back pain as a standalone intervention. Individual outcomes vary.
• Biologic disc repair (intra-annular fibrin injection): For patients whose adjacent-level symptoms are driven by annular tears confirmed on annulogram, a fibrin disc treatment uses an FDA-approved fibrin sealant to seal the tears under imaging guidance. The procedure takes under one hour, requires no incisions, and is performed under local anesthesia or light sedation. It is designed to address the structural source of disc pain rather than mask it. Individual outcomes vary; a clinical evaluation is required to determine candidacy.

For patients who have already experienced one failed spinal surgery, the decision about whether to pursue revision requires careful consideration of all structural options. See: How to Evaluate Spine Repair Options After Surgery.

Surgical Options

• Extension of fusion construct: The most common surgical response to symptomatic ASD — adding the adjacent level to the fusion. This eliminates motion at the new level and shifts stress further along the chain. It carries the same ASD risk at the next level and revision surgery risks including infection, hardware failure, and adjacent-level re-injury.
• Decompression without fusion: When stenosis rather than instability is the primary driver, decompression alone (laminectomy or foraminotomy) may relieve symptoms without extending the fusion. Candidacy depends on whether instability is present.
• Motion-preserving implants: Artificial disc replacement or dynamic stabilization at the adjacent level — explored in research settings as alternatives to rigid fusion extension. Evidence for long-term outcomes remains evolving.

Is Biologic Disc Repair an Option for Adjacent Segment Disease?

For a subset of ASD patients, the primary driver of pain is not stenosis or instability but annular tears at the adjacent level — structural damage that allows disc material and inflammatory mediators to leak and irritate surrounding nerves. In these patients, annular tear repair using an intra-annular fibrin injection addresses the disc at the structural level.

Among the most-tracked outcomes in the fibrin procedure registry — over 7,000 procedures with long-term follow-up — the reported success rate is 83%, with individual outcomes varying. VAS pain scores in fibrin outcome studies dropped from a baseline of 72.4 mm to 33.0 mm at 104 weeks. More than 13,000 of these procedures have been performed nationally. For post-fusion patients specifically, outcome data show 80% of patients who had failed a prior surgery reported positive outcomes with fibrin injection — individual outcomes vary.

The fibrin sealant used in the procedure is FDA-approved as a sealant. Specific clinical applications, candidacy, and outcomes vary by patient. A clinical evaluation and annulogram are the only ways to determine whether the adjacent-level disc tears are present, confirmed, and appropriate for this approach.

See illustrative outcomes in patients who pursued this path: 70% Pain Reduction with Fibrin Disc Repair: How a Post-Fusion Patient Achieved Mobility Without Revision Surgery and 80% Pain Reduction After Failed Fusion: How a Retired Construction Worker Recovered with Intra-Annular Fibrin Injection. (These are illustrative composite scenarios drawn from outcome patterns; they are not specific patient records.)

What Questions Should You Ask Your Care Team?

For patients navigating an ASD diagnosis, these questions help clarify the options before committing to revision surgery:

1. Is my adjacent-level change radiographic only, or is it confirmed as the source of my symptoms?
2. Has an annulogram been performed to identify whether annular tears are present at the adjacent level?
3. If revision fusion is recommended, what is the plan for the level above or below the new construct?
4. What non-surgical structural options have been evaluated, and why were they ruled in or out?
5. What does the evidence show for my specific type of adjacent-level pathology — disc herniation, stenosis, or instability?
6. If I choose not to have surgery now, what monitoring is appropriate?

For additional guidance on navigating care after a prior spine surgery, see: How to Get Answers for Your Post-Surgery Back Pain.

Frequently Asked Questions About Adjacent Segment Disease

How common is adjacent segment disease after spinal fusion?

Radiographic adjacent-level changes are common — studies find them in a substantial proportion of fusion patients within five years. Symptomatic ASD that requires further intervention is less common but is among the leading causes of revision surgery, with lumbar fusion revision rates exceeding 20% within 10 years. Individual outcomes vary.

Is adjacent segment disease the same as failed back surgery syndrome?

They overlap but are not identical. Failed back surgery syndrome (FBSS) describes persistent or new pain after any spine surgery. ASD is a specific mechanism — accelerated adjacent-level degeneration caused by fusion mechanics. ASD can be a cause of FBSS, but FBSS has other causes including scar tissue, hardware issues, and incomplete decompression. See: What Is Failed Back Surgery Syndrome?

Can adjacent segment disease be treated without surgery?

For patients whose ASD is driven primarily by annular tears at the adjacent level — confirmed on annulogram — non-surgical biologic disc repair is evaluated as an alternative to revision fusion. Physical therapy and targeted interventional care are also part of the non-surgical spectrum. A clinical evaluation is the only way to determine which approach fits a specific patient’s anatomy and findings.

How is an annulogram different from an MRI for diagnosing ASD?

An MRI visualizes disc structure and signal but cannot confirm whether a tear is actively leaking or causing pain. An annulogram injects contrast dye directly into each disc under fluoroscopy — when dye leaks through a tear, it confirms the structural defect and its location. For patients being evaluated for biologic disc repair, the annulogram is the diagnostic step that confirms candidacy.

Does extending the fusion fix adjacent segment disease?

Extending the fusion to include the adjacent level eliminates motion there but transfers mechanical stress to the next level up or down. This is a documented pattern in the revision surgery literature. For some patients with instability or severe stenosis, extension may be necessary; for others, structural disc-level interventions or conservative care are evaluated first. The decision depends on individual anatomy, symptom severity, and clinical findings.

Is fibrin disc treatment covered by VA benefits for veterans with adjacent segment disease?

Under the Mission Act, the procedure may be a covered VA benefit when the VA cannot provide timely or appropriate care. VA coverage is determined case-by-case by the VA, not by Valor Spine. The Valor team works directly with VA referral coordinators and handles the paperwork — veterans do not have to navigate that process alone. A clinical evaluation determines whether a veteran meets the candidacy criteria for the procedure. See how one veteran navigated this path: Cervical Adjacent Segment Disease Relief with Fibrin: How a Retired Army Crew Chief Avoided Revision Fusion. (Illustrative composite scenario.)

This content is for general informational purposes only and does not constitute medical advice, diagnosis, or treatment. It is not a substitute for evaluation by a qualified physician. Treatment decisions depend on your individual medical history and clinical findings. Schedule a consultation to discuss whether the procedure is right for you.

The fibrin sealant used in the procedure is FDA-approved as a sealant. Specific clinical applications, candidacy, and outcomes vary by patient.

VA coverage is determined case-by-case under Mission Act criteria by the VA, not by Valor Spine. Valor coordinates the referral process; the VA makes coverage decisions.