Adjacent Segment Disease
What is adjacent segment disease?
Adjacent segment disease is characterized by a degenerative process adjacent to a previously fused spine segment, with new onset of clinical symptoms such as radiculopathy, myelopathy, or instability.
Adjacent segment disease, also known as adjacent segment degeneration or adjacent segment pathology, is a condition in orthopedic surgery characterized by the degeneration of spinal segments adjacent to a previously fused vertebral segment. This degeneration can result in a range of symptoms and complications, and it is a significant consideration for patients undergoing spinal fusion procedures.
The risk of adjacent segment disease is an important consideration during decision-making for lumbar and cervical spinal fusion. While the development of this condition occurs in a wide variety of situations and each patient is unique, the typically quoted risk of developing breakdown above or below a lumbar or cervical fusion is 2-3% per year. This means that for most patients undergoing surgery, the 10-year risk of developing symptoms due to ASD is around 25-30%.
The primary cause of adjacent segment disease is believed to be the altered biomechanics of the spine following spinal fusion surgery. When a segment of the spine is fused, the normal motion and load distribution of the spine are disrupted. This can place increased stress on the spinal segments immediately above and below the fusion site, potentially leading to accelerated wear and degeneration of these adjacent segments. It can affect the lumbar or cervical spine.
The exact mechanisms behind adjacent segment disease are complex and multifactorial. Factors that may contribute to the development of adjacent segment disease include:
- Biomechanical Stress: Increased motion and stress at the adjacent segments can lead to accelerated degeneration.
- Genetic Predisposition: Some individuals may have a genetic predisposition to degenerative changes in the spine.
- Surgical Technique: The type of fusion, the extent of fusion, and the surgical approach can influence the risk of developing adjacent segment disease.
- Patient Factors: Age, body mass index, smoking status, and pre-existing degenerative changes also play a role.
Patients with adjacent segment disease may experience a variety of symptoms, which can vary depending on the location and severity of the degeneration. Common symptoms include:
- Back or Neck Pain: Persistent or worsening pain in the area adjacent to the fusion.
- Radiculopathy: Pain, numbness, or weakness radiating down the arms or legs, depending on the location of the affected segment.
- Neurological Deficits: In severe cases, patients may experience neurological deficits, such as loss of sensation or motor function.
Diagnosis typically involves a combination of clinical evaluation and imaging studies. A thorough patient history and physical examination are crucial. Imaging modalities such as X-rays, magnetic resonance imaging (MRI), and computed tomography (CT) scans can help visualize degenerative changes in the adjacent segments and assess the stability of the fusion.
The treatment option depends on the severity of the symptoms and the extent of degeneration. Treatment options range from conservative management to surgical intervention.
Conservative Management
- Physical therapy to strengthen the muscles supporting the spine and improve flexibility.
- Nonsteroidal anti-inflammatory drugs (NSAIDs), analgesics, and muscle relaxants to manage pain and inflammation.
- Epidural steroid injections or facet joint injections to reduce pain and inflammation.
Surgery
- In cases where conservative measures fail, or symptoms are severe, surgical intervention may be necessary. This may involve extending the fusion to include the degenerated adjacent segments.
- If there is significant nerve compression, surgical decompression of nerve roots or the spinal cord may be necessary.
In some cases, adjacent segment disease is unavoidable. The best prevention is consulting with a surgeon like Dr. Matthew Colman, who has the skills and expertise to discuss with you nonfusion alternatives as well as meticulous surgical techniques to help reduce the risk of adjacent segment disease. In other words, if fusion can be avoided, that is typically the best defense. If fusion is required, there are a variety of specialized techniques Dr. Colman employs to avoid the complication of ASD.
Schedule a consultation
Matthew Colman, MD, is an orthopedic surgeon at Northwestern Medicine in Chicago, Illinois. He specializes in degenerative spine conditions, spine trauma, spinal deformities, and spine oncology. His patients find him to be a kind, caring, and thorough surgeon, who has a wonderful bedside manner, and is knowledgeable and trustworthy. They note that he takes time to listen to his patients, explains conditions well and answers their questions.
Dr. Colman’s care philosophy is that surgery should be a last resort. He feels strongly that conservative treatments including physical therapy and anti-inflammatory medications and injections should be pursued to their fullest extent before entertaining surgery.
Contact him at Northwestern Medicine in Chicago, Illinois to schedule a consultation to receive the correct diagnosis and all your treatment options today.
References
- McDonald CL, Alsoof D, Glueck J, Osorio C, Stone B, McCluskey L, Diebo BG, Daniels AH, Basques BA. Adjacent Segment Disease After Spinal Fusion. JBJS Rev. 2023 Jun 12;11(6). doi: 10.2106/JBJS.RVW.23.00028. PMID: 37307327.
- Maragkos GA, Atesok K, Papavassiliou E. Prognostic Factors for Adjacent Segment Disease After L4-L5 Lumbar Fusion. Neurosurgery. 2020 Jun 1;86(6):835-842. doi: 10.1093/neuros/nyz241. PMID: 31245812.
At a Glance
Dr. Matthew Colman
- Internationally recognized expertise and thought leadership for a diverse range of spinal problems
- Patient-specific and humanistic approach which uses the latest technology and techniques
- Team centered approach prioritizes availability, communication, and support
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