Adjacent Segment Disease (ASD)

Top 5 Facts You Must Know About Adjacent Segment Disease (ASD)

What is Adjacent Segment Disease?
ASD as a Consequence of Spinal Fusion
Risk Factors for ASD
Diagnosing Adjacent Segment Disease
Treatment Options
Prevention Strategies
Summary & Takeaways

What is Adjacent Segment Disease?

Adjacent Segment Disease (ASD) refers to the degeneration or pathology that develops at spinal segments adjacent to a previously fused segment—typically in the lumbar or lumbosacral region. Once considered rare, it is now recognized as a frequent long-term complication of spinal fusion surgery. ASD can lead to new symptoms such as lower back pain, leg weakness, numbness, and may even require additional surgery if symptoms worsen.

Instrumented spinal fusion increases the risk of ASD due to altered spinal biomechanics. As motion is eliminated at the fused segment, increased stress is transferred to the neighboring, unfused segments—accelerating their degeneration.

Learn more about spinal fusion and related complications on our page about Lumbar Spine Pain.

ASD as a Consequence of Spinal Fusion

Adjacent Segment Disease is a well-documented consequence of spinal fusion surgery, yet it is often not thoroughly discussed with patients during preoperative planning. Fusion, while effective at stabilizing a problematic segment, alters the biomechanics of the spine. This change results in additional mechanical stress and mobility demand on the segments immediately above and below the fusion site.

A widely cited study by Ghiselli et al. (Spine, 2004) followed patients for over 10 years after lumbar fusion and found that the incidence of clinically significant ASD was approximately 16.5% at 5 years and increased to over 36% at 10 years.

Another long-term follow-up study by Park et al. (Spine Journal, 2004) showed that non-instrumented fusions had significantly lower rates of ASD (5.6%) compared to instrumented fusions (18.5%) over 13+ years.

Despite this data, discussions about ASD are often brief or overlooked in surgical consultations. This may be due to the delayed nature of ASD onset—typically developing years after the initial surgery—and the urgency to address the primary pathology.

At Dr. Amit Sharma’s Spine Practice, we take a comprehensive and transparent approach to spinal care. We educate our patients not just about the immediate surgical outcome, but also about long-term implications like ASD.

Risk Factors for ASD

Several factors increase the likelihood of developing ASD:

Fusion length – especially three or more spinal levels
Sagittal malalignment – improper alignment after surgery
Facet joint injury during instrumentation
Advanced age
Pre-existing degenerative disease in adjacent segments
High body mass index (BMI)
Osteoporosis or poor bone quality

Visit our guide on non-surgical spine care to explore options for managing back pain and avoiding unnecessary surgery.

Diagnosing Adjacent Segment Disease

Diagnosis typically includes:

– Detailed physical exam and medical history
– X-rays or MRI to assess adjacent spinal levels
– Rule-out of non-surgical causes of back pain

Radiographic evidence of degeneration at adjacent levels doesn’t always equate to symptoms. Therefore, it’s essential to correlate imaging with clinical findings before deciding on further treatment.

Treatment Options

Initial treatment is often non-surgical and may include:

– Physical therapy to offload stress on adjacent segments
– Anti-inflammatory medications
– Epidural steroid injections
– Chiropractic care or acupuncture, when appropriate

If conservative treatment fails, surgical options like decompression and extension of the fusion may be necessary—although outcomes for these revisions are typically more modest compared to primary surgery.

Learn about minimally invasive spine procedures we use to help avoid extended fusion.

Prevention Strategies

Prevention focuses on both surgical technique and patient-specific risk factors:

– Limiting the fusion length when possible
– Preserving sagittal balance
– Avoiding injury to adjacent facet joints during instrumentation
– Considering non-instrumented fusion in select cases
– Managing weight and underlying bone conditions

A patient-centered surgical plan, like those offered at our Long Island locations, ensures the best outcomes and reduces avoidable complications like ASD.

Summary & Takeaways

Adjacent Segment Disease is a common, well-documented, but often under-discussed long-term consequence of spinal fusion. While it doesn’t affect everyone, understanding your personal risk factors can help you and your provider make informed choices.

At Dr. Amit Sharma’s SpinePain Solutions, we provide honest, data-driven consultation before any procedure. We also maintain close relationships with physical therapists, chiropractors, acupuncturists, and spine surgeons—making us your ideal spine care partner in Nassau and Suffolk Counties.

If you’re experiencing new symptoms after a spinal fusion or exploring alternatives to surgery, contact us today to schedule your personalized consultation.

Sources:
Park et al., Spine Journal, 2004
Ghiselli et al., Spine, 2004
Surgical Neurology International – ASD Review