Degenerative Disc Disease (DDD)
What are the three major functions of the disc?
1) Spacer 2) Accommodate Movement 3) Distribute load
What is a Radiograph? What does it examine? Benefits?
An X-Ray. Even though discs are not visible, you can still establish the discs height. It will also show osteophytes + changes to the endplates that are characteristic of DDD
Describe the basic composition of the disc
Annulus Fibrosus: Tough outer layer of woven cartilage fibers. Contains the nucleus Nucleus Pulposus: Central portion of the disc. Jelly-like material that acts as a shock absorber Cartilaginous Endplates: Layers of collagen that exist on the superior and inferior aspects of the vertebral body. The discs are securely attached to the endplates
What is the Invertebral Foramen?
Between each pair of vertebrae, an opening that allows the spinal nerve to exit
What is an osteophyte? (Bone spurs)
Boney outgrowth associated w/ degeneration of cartilage at joints
Where is the dens located, and what is it's purpose?
C2 Extends cranially into C1 Acts as a pivot point for C1
Describe the common treatment options for DDD (2 Types)
Conservative Therapy- Non-surgical means Ex: Rest, physical therapy, weight management Decompression (direct and indirect) Direct: Physically removing the pieces of tissue exerting pressure onto neural element. Ex: Removal of disc herniation or an osteophyte coming in contact w/ a spinal nerve. Indirect: Increasing the amount of room for neural structures by restoring height of the disc space. Ex: Placing a graft
What are the two types of decompression?
Direct and indirect
What is indirect decompression? Example?
Increasing the amount of room for the neural structures by increasing or restoring the height of the disc space Placing a graft/ spacer
What is a Discography?
Ink injected into the disc. If dye leaks, indication of tears in the annulus
What is a CT scan? What does it show?
Multiple views: axial, lateral, and coronial. 3D reconstructed images. Allows surgeons to see the openness of vertebral+ invertebral foramina, as well as the condition of the facet joints.
Describe the degenerative disc process and its conditions (3 phases, DIS)
Phase 1: Dysfunction- Degenerative cascade begins to get small tears in the annulus. Experience acute or chronic pain, usually relieved by rest. Phase 2: Instability: Multiple annular tears, internal disc disruption and loss of disc height. From loss of height, spinal nerves may become pinched. Disc herniations may occur. Phase 3: Stabilization- Further disc deterioration, narrowing endplate destruction and osteophyte formation. The body tries to stabilize the degenerated spinal segment by fusing the vertebrae together. Fewer episodes of pain, unless the entrapment of spinal nerves occurs.
What is direct decompression? What are some examples?
Physically removing the pieces of tissue that are exerting pressure onto a neural element. Removal of a disc herniation Removal of an osteophyte
What are the symptoms of degenerative disc disease? (2 Types) What are the effects?
Radicular Symptoms: Indicate impingement of a spinal nerve. Numbness, tingling, weakness, paresthesia (pins and needles). Region corresponds w/ dermatome. Myelopathic Symptoms: Indicate impingement of the spinal cord. Gait disturbances, bowl+ bladder dysfunction and generalized weakness. Occur over a larger non-specific area, often on both sides of the body.
What is a Foraminotomy? Why might a Foraminotomy be performed? Advantages? Disadvantages?
Removal of sections of the Lamina + Facet to increase the volume of the invertebral foramen A Foraminotomy decompresses the spinal nerve by increasing the diameter of the invertebral foramen Advantages- Decompresses the neural elements without fusion. Disadvantages- Not effective for myelopathy and pathology toward the midline. May lead to spinal instability.
What is a Laminectomy? Why might a Laminectomy be performed? Advantages? Disadvantages?
Removal of the Lamina Commonly done to decompress the spinal cord Hardware may need to be placed to re establish stability Advantages-Increases the volume of the vertebral foramen Disadvantages- May destabilize the spine if performed over multiple levels, requiring instrumentation.
What is a Discectomy + Fusion? What are the steps?
Removal of the disc 1) Remove the disc 2) Place spacer 3) Graft Augmentation: additional bone graft is placed in and around the spacer 4) Stabilization 5) Fusion -6-9 months to become stable - Up to 7 years to completely remodel - Instrumentation may fail if fusion does not occur
What is a Laminoplasty? What does it do? Advantages? Disadvantages?
Reshaping the lamina to increase the volume of the vertebral foramen Generally requires instrumentation to maintain the lamina in new position Advantages- Increases the volume of the vertebral foramen over multiple levels without removing protective function. Disadvantages- Technically more demanding than a Laminectomy.
What is an MRI? What does it show? Benefits?
Shows water content Examines the soft tissues of the body Sagittal + axial views Examine the health and hydration of the discs. (Black disc disease) Examine any constricted neural elements (nerves, spinal cord)
Spondylosis
Spondylolisthesis is the forward displacement of one vertebra over another.
What is a Laminotomy? Why might a Laminotomy be performed? Advantages? Disadvantages?
The removal of part of the lamina - May be done to relieve compression of a neural element, or to gain access to the disc or spinal nerve Advantage- Allows access to neural elements and disc from posterior approach Disadvantage- Not often a stand alone procedure
What is a Microdiscectomy and why might one be performed?
The removal of the herniated portion of a disc Portions of the lamina or facet may be removed to gain access
