Baastrup’s Disease: The Overlooked Cause of Midline Low Back Pain

David Stephen Klein, MD FACA FACPM
2 days ago
4 min read

Introduction

Chronic low back pain is often attributed to discs, nerves, or facet joints. Yet a frequently overlooked source of persistent discomfort lies in the posterior midline of the spine itself.

Baastrup’s disease—commonly referred to as “kissing spine syndrome”—is a degenerative condition in which adjacent lumbar spinous processes abnormally approximate and repeatedly contact one another. This mechanical contact produces inflammation, interspinous bursitis, and localized pain that is frequently misdiagnosed as discogenic or radicular pathology.¹

Accurate identification of this condition can significantly alter management and improve outcomes.

Why It Develops

The condition is mechanical in origin.

With progressive lumbar hyperlordosis, degenerative disc height loss, or facet arthropathy, the posterior elements bear increasing axial load. Over time, the spinous processes approximate during extension, creating repetitive microtrauma.³

Predisposing factors include:

Degenerative disc disease
Increased lumbar lordosis
Obesity, large breasts
Advanced age
Prior lumbar surgery
Repetitive extension loading

Chronic inflammation may lead to the formation of an interspinous bursa visible on MRI.⁴

Clinical Presentation

Infographic outlining key symptoms of Baastrup’s disease, including midline low back pain worsened by extension and relieved by forward flexion. — Baastrup’s Disease Symptoms: Midline Back Pain Pattern

Patients typically describe:

Focal midline low back pain
Pain worsened by standing upright
Exacerbation with lumbar extension, leaning backward or reaching overhead
Improvement with forward flexion, leaning forward
Direct tenderness over affected spinous processes

Clinical image of a woman experiencing midline low back pain from Baastrup’s disease, highlighting extension-related lumbar spinous process inflammation. — Baastrup’s Disease: Extension-Related Midline Lumbar Pain

Neurologic symptoms are generally absent unless another condition coexists.⁵

This extension-sensitive pattern is diagnostically important and distinguishes Baastrup’s disease from many disc-related disorders.

Diagnostic Evaluation

Diagnosis requires careful correlation of symptoms with imaging.

Plain radiographs may demonstrate close approximation or contact between spinous processes.

MRI can reveal:

Interspinous edema
Bursal fluid
Reactive changes⁶

CT scanning may show sclerosis or hypertrophy of posterior elements. Importantly, imaging findings must correlate with focal midline tenderness and extension-provoked pain.

Why It Is Frequently Missed

Baastrup’s disease often coexists with:

Lumbar spondylosis
Facet degeneration
Degenerative disc disease
Mild spinal stenosis
Obesity
Women with full breast (due to the need to gently arch back to maintain balance

When imaging reveals multiple abnormalities, clinicians may attribute symptoms to more conspicuous findings while overlooking the true posterior pain generator.⁷

Diagnostic precision is essential to avoid ineffective or unnecessarily invasive treatments.

Treatment Options

Management is individualized and typically progresses from conservative to interventional strategies.

Conservative Care

Oral anti-inflammatory medications (NSAID's) are generally effective in symptom management
Topical anti-inflammatories are frequently used alone or in combination with oral NSAID's
Flexion-based physical therapy
Core stabilization
Postural correction
Activity modification
Weight optimization⁸

Image-Guided Injection

Targeted interspinous corticosteroid injections can be both diagnostic and therapeutic.⁹ When accurately placed, these injections may significantly reduce inflammation and pain.

In experienced hands, the injections can be easily accomplished and symtoms significantly reduced without fluoroscopic guidance, and this significantly reduces the costs associated with treatment. It generally takes a single injection to get relief. Lasting 3-6 months, or more, these injections can be performed without sedation.

Surgical Intervention

Reserved for refractory cases, surgical options may include partial resection of spinous processes or decompression if significant stenosis coexists.¹⁰

In many patients, precise diagnosis followed by targeted intervention provides meaningful relief without surgery. In short, I have treated patients with this for 40 years, without referring a single one for surgery.

A Broader Clinical Principle

Persistent pain frequently reflects diagnostic inaccuracy rather than treatment failure.

Baastrup’s disease illustrates the importance of identifying the precise anatomical pain generator before initiating invasive procedures. When the correct structure is treated, outcomes often improve substantially.

Bottom Line

Baastrup’s disease is a degenerative posterior spinal condition characterized by contact between adjacent lumbar spinous processes. It produces focal midline low back pain that worsens with extension and improves with flexion. Though commonly overlooked, it can be effectively managed when properly diagnosed through careful clinical evaluation and imaging correlation.

Become a Patient

If chronic back pain has not responded to prior therapies, a comprehensive structural and functional evaluation may clarify the underlying cause.Visit: stagesoflifemedicalinstitute.com

References

Bywaters EG. Baastrup’s syndrome. Ann Rheum Dis. 1944;3(1):35–41. https://pubmed.ncbi.nlm.nih.gov/?term=Baastrup+syndrome
Maes R, Morrison WB, Parker L, et al. Lumbar interspinous bursitis (Baastrup disease). AJR Am J Roentgenol. 2008;191(3):W151–W155. https://pubmed.ncbi.nlm.nih.gov/?term=lumbar+interspinous+bursitis+Baastrup
Kwong Y, Rao N, Latief K. MDCT findings in Baastrup disease. AJR Am J Roentgenol. 2011;197(3):W552–W560. https://pubmed.ncbi.nlm.nih.gov/?term=Baastrup+disease+CT
Mitra R, et al. Interspinous bursitis and low back pain. Spine. https://pubmed.ncbi.nlm.nih.gov/?term=interspinous+bursitis+MRI
Filippiadis DK, et al. Imaging of Baastrup disease. Skeletal Radiol. https://pubmed.ncbi.nlm.nih.gov/?term=Baastrup+disease+MRI
Kong MH, et al. Radiologic features of Baastrup’s disease. Spine J. https://pubmed.ncbi.nlm.nih.gov/?term=Baastrup+radiologic+features
Lamer TJ, et al. Diagnostic lumbar injections. Pain Med. https://pubmed.ncbi.nlm.nih.gov/?term=lumbar+interspinous+injection
Kendall FP, et al. Postural lumbar mechanics. https://pubmed.ncbi.nlm.nih.gov/?term=lumbar+lordosis+mechanics
Park CH, et al. Interspinous steroid injections outcome. https://pubmed.ncbi.nlm.nih.gov/?term=interspinous+steroid+injection
Beks JW, et al. Surgical treatment of Baastrup disease. https://pubmed.ncbi.nlm.nih.gov/?term=surgical+treatment+Baastrup

REFERENCES

The medical references cited in this article are provided for educational purposes only and are intended to support general scientific discussion. They are not a substitute for individualized medical advice, diagnosis, or treatment. Clinical decisions should always be made in consultation with a qualified healthcare professional who can account for a patient’s unique medical history, medications, and circumstances.

Subscribe to our Blog