central spinal stenosis

Central vs. Lateral Hypertrophy in Central Lumbar Spinal Canal Stenosis: New Insights from a Comparative Study


Central Lumbar Spinal Canal Stenosis (CLSCS) is a prevalent spinal disorder causing pain and discomfort, especially in the elderly. Ligamentum flavum hypertrophy is recognized as a significant contributor to this condition. A recent study1 further delves into the variations of hypertrophy in different regions of the ligament and their implications.


Prevalence, symptoms, and causes of CLSCS

Central Lumbar Spinal Canal Stenosis (CLSCS) is a widespread spinal disorder primarily affecting the aging population. This condition, characterized by the narrowing of the spinal canal in the lumbar region, can lead to a variety of distressing symptoms, impacting individuals’ quality of life. Let’s delve deeper into the prevalence, symptoms, and underlying causes of CLSCS to understand this complex spinal condition comprehensively.

Prevalence of CLSCS: CLSCS is a prevalent spinal disorder with a significant place within the spectrum of age-related degenerative conditions. Studies have reported a prevalence rate of approximately 27.2% within the general population, emphasizing its substantial impact on individuals as they grow older. This prevalence increases notably among the elderly, aligning with the natural progression of degenerative changes that occur within the spine over time.

Symptoms of CLSCS: CLSCS can vary in nature and intensity, but they often center around discomfort and pain within the lower back and lower extremities. Some of the common symptoms include:

  • Low Back Pain: Individuals with CLSCS frequently experience chronic low back pain, ranging from mild discomfort to more severe, persistent pain. This pain often worsens with physical activity and standing for prolonged periods.
  • Gluteal Pain: Pain that radiates to the buttocks and gluteal region is another hallmark of CLSCS. This discomfort can be accompanied by a sense of heaviness or pressure in the area.
  • Neurogenic Claudication: Neurogenic claudication refers to the radiating pain that extends down the legs. This pain may be described as sharp, shooting, or tingling, typically occurring during walking or prolonged standing. Individuals often find relief when sitting or bending forward.


CLSCS is a multifactorial condition, meaning multiple factors contribute to its development. Some of the fundamental underlying causes include:

  • Arthritic Changes: Degenerative changes in the facet joints connect the vertebrae and can lead to arthritic conditions. These changes contribute to the narrowing of the spinal canal and subsequent nerve compression.
  • Disc Herniation and Osteophytes: Intervertebral discs cushion the spinal vertebrae can degenerate over time, leading to herniation or bulging. Additionally, the growth of bony outgrowths known as osteophytes further contributes to spinal canal narrowing and nerve compression.
  • Ligamentum Flavum Hypertrophy: The ligamentum flavum (LF) is a ligament that helps maintain spinal stability. However, with age and degeneration, the LF can become hypertrophied or thicker. This hypertrophy contributes significantly to nerve root compression, spinal canal narrowing, and the associated symptoms.
  • Loss of Disc Height: Disc degeneration can lead to a loss of intervertebral disc height. This reduction in disc space contributes to the narrowing of the spinal canal and further exacerbates nerve compression.
  • Inflammatory Changes: Inflammation within the spinal structures can accelerate the degenerative cascade, leading to structural changes that contribute to CLSCS.

Understanding the prevalence, symptoms, and underlying causes of CLSCS provides a solid foundation for comprehending the complexity of this condition. As research continues to uncover more insights into the interplay of various factors, medical professionals can refine diagnostic and treatment approaches, ultimately improving the lives of individuals affected by CLSCS. If you suspect you might have CLSCS or experience related symptoms, consulting a healthcare provider is crucial for accurate diagnosis and tailored management strategies.


The ligamentum flavum (LF), an essential component of the spinal anatomy, plays a significant role in the development and progression of Central Lumbar Spinal Canal Stenosis (CLSCS). This ligament, situated within the spinal canal, serves crucial functions in maintaining spinal stability and protecting vital neural structures. However, in the context of CLSCS, the LF’s role becomes twofold: on the one hand, it contributes to stability, and on the other, its hypertrophy can lead to nerve compression and subsequent symptoms. Let’s explore the multifaceted role of the LF in the context of CLSCS in greater detail.

Maintaining Spinal Stability

The ligamentum flavum is a fibrous connective tissue that spans between adjacent vertebrae within the spinal column. It forms part of the posterior aspect of the vertebral canal and aids in maintaining the integrity and stability of the spinal column. Acting as a reinforcement structure, the LF helps prevent excessive movement between vertebrae, especially during activities involving bending, twisting, or supporting the body’s weight. This stability is crucial to protect the delicate spinal cord and nerve roots from potential trauma or injury.

Contributing Factors to LF Hypertrophy

As the spine undergoes degenerative changes due to factors such as aging, wear and tear, and inflammation, the LF can undergo hypertrophy, or an abnormal increase in thickness. Several factors contribute to LF hypertrophy in the context of CLSCS:

  • Mechanical Stress: Over time, mechanical stress due to factors like repeated movement and poor posture can lead to microtrauma within the LF. This can trigger an inflammatory response and, subsequently, fibrotic changes that cause the LF to become thicker.
  • Degenerative Changes: Degeneration of adjacent spinal structures, including facet joints and intervertebral discs, can influence the LF. As these structures deteriorate, they may stimulate an inflammatory response in the LF, contributing to fibrosis and hypertrophy.
  • Loss of Elastic Fibers: The normal LF structure consists of elastic fibers and collagen fibers. However, in CLSCS, there is a shift toward increased collagen fibers and decreased elastic fibers. This change affects the LF’s flexibility and can lead to stiffness and thickening.

Hypertrophy and Nerve Compression

While the LF’s hypertrophy is partly a response to protect the spinal structures, it can inadvertently lead to nerve compression and spinal canal narrowing. The thickened LF can impinge upon the nerve roots and the dural sac, which encases the spinal cord and nerves. As a result, the nerve roots become compressed, leading to pain, discomfort, and other symptoms associated with CLSCS, including lower back pain, radiating leg pain, and neurogenic claudication.

Implications for Diagnosis and Treatment

Understanding the LF’s dual role in spinal stability and the pathogenesis of CLSCS is crucial for accurate diagnosis and effective treatment. Imaging techniques such as Lumbar Magnetic Resonance (L-MR) play a pivotal role in assessing LF hypertrophy and its impact on nerve compression. Healthcare professionals can tailor treatment strategies to alleviate symptoms and improve overall spinal health by identifying the extent and location of hypertrophy.

In conclusion, the ligamentum flavum’s involvement in Central Lumbar Spinal Canal Stenosis exemplifies the intricate balance between spinal stability and pathological changes. Recognizing its role in both contexts offers insights that can guide medical interventions, helping individuals affected by CLSCS find relief and enhanced quality of life.


  • Differences in CLFT and LLFT:
    • Mean CLFT is significantly lower than mean LLFT in the control group
    • Implication: Variations in hypertrophy exist between central and lateral areas of LF
  • Association with CLSCS:
    • Both CLFT and LLFT are significantly associated with CLSCS
    • Faster increase rate of CLFT compared to LLFT in the CLSCS group
  • Predictive Accuracy:
    • CLFT is a more sensitive predictor of CLSCS than LLFT
    • Validity confirmed through ROC curve analysis with high sensitivity and specificity
  • Asymmetric Hypertrophy:
    • Imaging confirmation of asymmetric LF hypertrophy in CLSCS
    • The study suggests lifelong asymmetric mechanical stress as a potential cause

Clinical Implications and Future Considerations

  • Improved diagnostic criteria for CLSCS: Considering both CLFT and LLFT
  • Tailoring treatment approaches: Recognizing variations in hypertrophy for more effective interventions
  • Potential research directions: Exploring other anatomic causes and including multiple morphologic parameters for diagnosis

Study’s Methodology and Limitations

  • Use of Lumbar Magnetic Resonance (L-MR) imaging for measurement
  • Strict control for age, focusing on the L4 to 5 level
  • Retrospective control evaluation with a relatively small sample size


  • This study sheds new light on the intricacies of Central Lumbar Spinal Canal Stenosis by examining the variations in ligamentum flavum hypertrophy. The findings highlight the significance of both central and lateral regions of LF, indicating that the location of hypertrophy influences the prediction and manifestation of CLSCS symptoms. The study underscores the importance of considering multiple parameters in diagnosis and treatment planning, potentially leading to enhanced clinical outcomes for individuals affected by CLSCS. As research in this field progresses, a more comprehensive understanding of the condition’s complexities could pave the way for advanced diagnostic methods and personalized therapeutic strategies.