Baastrup’s disease, also known as “kissing spine syndrome,” is a spinal condition where the spinous processes, bony protrusions at the back of the vertebrae, come into close contact or rub against each other. This contact can be a source of back pain. While often underdiagnosed, Baastrup’s disease is a treatable condition that can affect a person’s comfort and mobility.
The Nature of Pain in Baastrup’s Disease
Individuals with Baastrup’s disease experience midline pain in the lower back. This pain can feel like localized tenderness, a deep ache, or a sharp sensation. Activities or positions involving spinal extension, such as prolonged standing, walking, or arching the back, tend to worsen the pain. Direct pressure on the affected area can also reproduce or intensify the pain.
The pain can sometimes extend to the buttocks or thighs, but generally does not radiate below the knee. Its intensity varies widely, from mild irritation to severe pain that limits daily activities. Flexing the spine often provides relief.
Why Baastrup’s Disease Causes Pain
The pain in Baastrup’s disease stems from mechanical irritation and inflammation caused by the close approximation of adjacent spinous processes, often called “kissing spines.” This repetitive friction can lead to changes in soft tissues and bone. These include inflammation, bone marrow edema, and bursitis, which is the inflammation of fluid-filled sacs that can develop between the rubbing bones.
Over time, constant contact can also result in degenerative bone changes, such as flattening, sclerosis (hardening), and the development of small cysts. An increased lumbar lordosis, an excessive inward curve of the lower back, or age-related degenerative changes in the spine are contributing factors increasing the likelihood of spinous processes coming into contact. These inflammatory processes and structural alterations directly contribute to the pain.
Confirming the Pain’s Origin
Diagnosing Baastrup’s disease as the pain source involves clinical evaluation and imaging studies. A physical examination reveals tenderness when pressure is applied over the affected spinous processes, and pain often worsens with spinal extension. Imaging confirms the condition.
X-rays can show the close approximation or enlargement of the spinous processes. Computed tomography (CT) scans offer more detailed views of bony changes, while magnetic resonance imaging (MRI) detects inflammation, bone marrow edema, and bursitis in soft tissues. A diagnostic injection of a local anesthetic into the suspected interspinous space can provide temporary pain relief, further supporting Baastrup’s disease as the cause.
Relieving the Pain
Managing the pain associated with Baastrup’s disease begins with conservative approaches. Rest and activity modification, avoiding pain-aggravating movements, are often recommended. Physical therapy is used to strengthen core muscles, improve posture, and reduce excessive lumbar lordosis, decreasing mechanical stress. Over-the-counter pain relievers, such as nonsteroidal anti-inflammatory drugs (NSAIDs), reduce inflammation and pain.
If conservative measures are insufficient, targeted interventions may be considered. Corticosteroid injections directly into the interspinous space or bursa reduce inflammation and provide pain relief. For longer-lasting relief, radiofrequency ablation, a minimally invasive procedure that uses heat to disrupt pain signals from specific nerves, may be an option. Surgical intervention, which might involve removing a portion of the affected spinous process or interspinous decompression, is generally reserved as a last resort for severe, persistent pain that has not responded to other treatments.