The Functionally Unstable Spine

A functionally unstable spine may be the cause of a person's back pain. It is a painful disorder thought to result from a loss of the spine’s ability to maintain appropriate mechanical stiffness throughout it's NORMAL range of movements. In biomechanical terms, spinal stiffness refers to the spine’s ability to prevent unwanted movement or buckling. People often think of stiffness as a bad thing. It isn't always. When a muscle contracts, it creates both force and stiffness. Spinal stiffness is necessary to perform basic daily movements. With minimal amount of force, muscles around the spine act as guy wires, a tensioned cable designed to add stability to a free-standing structure.

It is important to note that a functionally unstable spine is not synonymous with hypermobility or radiographic instability. Hypermobility and radiographic instability is where spinal joint motion is excessive BEYOND normal joint movement. This is typically demonstrated on appropriate imaging.

Some indicators that a functionally unstable spine may be the cause of a person's back pain often include:

• Multiple unpredictable episodes triggered by sudden or trivial movements or sustained postures
• Reports of catching or locking associated with a feeling of giving way or consistent clicking or clunking noises which may be followed by a minor aching for a few days
• Immediate pain with transitional movements like sit to stand
• Temporary response to adjustments
• Decreased response to adjustments over time

40-60% of typical back pain patients experience recurrence or low level chronic symptoms, but a pattern of sudden flare ups caused by minimal loading events may be linked in this instability phenomena. The theory behind this is that poor stability increases the risk of a “spinal buckling” under minimal weight, often just bodyweight movements, and triggers episodes. This accumulative repetitive buckling makes it difficult for the patient to truly feel a healing of their back pain. 

The safest and most effective conservative treatment for patients with a functionally unstable spine is through an effective spine stabilization exercise routine. Stabilization exercises are designed to improve spinal stability, relieve pain and increase movement performance. A large number of muscles cross the spine, and all contribute to the modulation of lumbar stability and movement to some extent. Multiple imaging studies have demonstrated muscle atrophy in patients with chronic back pain. A stabilization exercise routine is designed to target these areas of muscle atrophy to improve strength and reduce muscle fatigue over time.

Some of the muscles that are most commonly weakened and atrophied in patients with a functionally unstable spine are:

• Multifidus
• Quadratus lumborum
• Transverse Abdominis
• Internal and External Abdominal Obliques
• Gluteus Maximus
• Gluteus Medius
• Diaphragm

Most people are surprised to learn that the diaphragm, which is mainly involved in breathing, is a key muscle in creating spinal stability. As the roof of the cylinder of muscles that surround the spine and assist with stability, the diaphragm is a major contributor to intraabdominal pressure and therefore lumbar stability. The diaphragm contributes to this spinal stiffness before the initiation of large limb movements to assist with spinal stability and greater strength of the arms or legs.

Some of the most effective stabilization exercises studied include:

• Learning to find and maintain a neutral spinal position
• Isometric contractions of the multifidus and transverse abdominis
• Dead bug
• Supine pelvic bridge
• Side bridge
• Bird dog
• Bear crawl
• Reverse Hyperextension
  
• Planking with variations

Once these exercises are mastered, a person suffering from a functionally unstable spine can gradually progress to various bodyweight loading strategies that would ordinarily be seen a training weight training environment. This type of training of the spine will carry over into the performance of functional activities, daily living activities, and work ultimately resulting in reduced episodes of functionally unstable back pain.

If you feel your back pain is the result of a functionally unstable spine, please click the link below to request an appointment!

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