Low Back Degenerative Disc Disease, Disc Herniation, Spinal Stenosis

General Anatomy of the Spine

The spine or backbone is made up of a series of bones known as “vertebrae”. The spine is divided into 5 major sections:

  1. Cervical spine (neck): contains 7 vertebrae labeled C1 to C7
  2. Thoracic spine (mid-back): contains 12 vertebrae labeled T1-T12
  3. Lumbar spine (low-back): contains 5 vertebrae labeled L1 to L5
  4. Sacrum (part of the pelvis): contains 5 fused sacral vertebrae
  5. Coccyx (tailbone): a triangular bone that makes up the end of the spinal column

The vertebrae of the lumbar spine are the largest in size. This allows for the low back to function as the major weight-bearer of the spine. In addition to carrying the weight of the torso and head, the structure of the lumbar spine also permit significant range of motion. While low back segments L4 and L5 allow a great deal of spinal rotation, they also take on the largest amount of weight from the body. This places the L4/L5 segment at high risk for damage. 


Located between each set of spinal vertebrae are small cushions known as “intervertebral discs.” These discs function to prevent bone-on-bone contact between the vertebrae and act as shock-absorbers for stresses placed on the spine.

The vertebrae of the spine surround and protect the spinal cord, which is located within the spinal canal. Connecting to the spinal cord and exiting from between each vertebra are the “spinal nerves.” There are both sensory and motor spinal nerves that carry information between the brain and different parts of the body. Sensory nerves, which exit from the left and right side of each vertebra, connect to various patches of skin and provide us with the sense of touch. Motor nerves also exit on the left and right of each spinal segment and carry signals from our brain to specific muscle groups, allowing movement to occur.        

Conditions Affecting the Back

  1. DEGENERATIVE DISC DISEASE (DDD):

DDD, also known as “osteoarthritis” (OA) of the spine, is a condition associated with the natural aging process and describes a general wear-and-tear that occurs over time. DDD is similar to rust formation in the joints and can result due to damage of intervertebral discs, decreased joint cartilage, and/or development of bone spurs.

DDD can cause decreased joint mobility, spinal instability, and decreased space between vertebrae. With reduced space, spinal nerves become compressed which can cause symptoms such as back pain, radiating symptoms into the leg, tingling/numbness, sensory loss, muscle weakness, loss of reflexes, and/or bowel and bladder dysfunction in more severe cases.

  1. DISC HERNIATION:

Intervertebral discs consist of an outer ring and soft, inner centre. A disc herniation occurs when the central portion bulges out into the damaged outer layers. Herniated discs can result from degenerative changes with age, trauma, or lifting injuries. When a disc herniation causes compression of the spinal cord or nerve root, it can result in symptoms such as back pain, radiating symptoms into the leg, tingling/numbness, loss of sensation, muscle weakness, loss of reflexes, and/or bowel and bladder dysfunction in more severe cases. 

  1. SPINAL STENOSIS:

Spinal stenosis is a condition that occurs due to abnormal narrowing of the spinal canal. This can be caused by age-related degeneration within the spine or “spondylolysthesis” (i.e. when one vertebra slips forward/backward on another). Symptoms of spinal stenosis can include back pain, buttock pain, radiating symptoms into the legs, tingling/numbness, loss of sensation, muscle weakness, loss of reflexes, and/or bowel and bladder dysfunction in more severe cases.



Common Symptoms

  1. PAIN AND STIFFNESS
  2. MUSCLE SPASM
  3. LOSS IN RANGE OF MOTION
  4. NEUROLOGICAL SYMPTOMS
    • Tingling
    • Numbness
    • Sensory loss
    • Muscle weakness
    • Loss of reflexes
    • Bowel and bladder dysfunction

Treatment Options:


Prognosis

Degenerative disc disease (DDD), disc herniation, and spinal stenosis are all chronic conditions of the back. As such, with the exception of surgery, there is no cure because the areas that have developed “rust” cannot be replaced. Therefore, the focus of conservative treatment is to reduce and control current symptoms and prevent further decline. While symptoms may improve (e.g. less pain, better range of motion, less neurological symptoms), depending on the individual and condition severity, recovery may plateau at a certain level.

Ideally, the level of recovery should be sufficient for day-to-day functioning. However, if the level where one plateaus is not adequate, limitations in daily activities may occur and more invasive treatment (i.e. injection)  may be considered.