Degenerative Disc Module Flashcards
Contains collagen fibers and proteoglycans
Nucleus pulposus
Water attracting proteins
Proteoglycans
What is the role of the annulus?
To contain the nucleus
True or false: intervertebral discs are avascular
True
How does the disc receive nutrients?
Vertebral route (through endplates from vessels in vert body)
Annular route (small vessels in outer third of annulus)
What are the nerve endings in the outer third of nucleus called?
Sinuvertebral nerves
Three major functions of disc
Spacer
Distribute Load
Accommodate movement
Phases of degenerative cascade
Dysfunction
Instability
Stabilization
Describe dysfunction phase of degen cascade
Small tears develop in annulus - acute or chronic back pain resolves with rest
Describe instability phase of degen cascade
Multiple annular tears, internal disc disruption, loss of height results in hyper mobility of motion segment
Describe stabilization phase of degen cascade
Further disc deterioration, disc space narrowing, endplate disruption, and osteophyte formation
Can result in general laxity in annulus
Bulging disc
Nucleus begins to protrude through a year in annulus in one area
Herniated disc
The type of herniation in which a portion of disc that has protruded through the annulus remains attached to remain material
Extruded disc herniation
Protruding portion of disc detached from remainder of disc
Sequestration disc herniation
Herniation towards midline putting pressure on spinal cord or cauda equina
Central herniation
Can result in weakness and numbness in lower extremities, bowel/bladder dysfunction, difficulty walking
Central herniation
May experience localized numbness, weakness, and tingling
Far lateral herniation
Generally affects spinal nerve
Far lateral herniation
When a herniation affect both spinal cord and spinal nerve
Paracentral herniation
When disc herniates through endplate
Schmorl’s Node
Condition that develops when the ligaments and posterior elements hypertrophy, enlarge, and the vertebral foramen narrows
Spinal stenosis
Numbness and tingling
Paresthesia
Intermittent pain or paresthesia in the legs that is brought on by standing and relieved by sitting
Neurogenic claudification
Compression of multiple spinal nerves within cauda equina
Cauda equina syndrome
Symptoms of cauda equina syndrome
Caused by lumbar stenosis or central herniation causing bilateral leg pain and parathesia, bowel and bladder dysfunction, and saddle anesthesia (loss of sensation restricted to area of buttocks and perineum)
Type of spondylolisthesis caused by abnormality in formation of Spine
Type 1 - Congenital
This type of spondylolisthesis is caused by a defect in pars articularis
Type 2 - Isthmic
Type of spondylolisthesis caused by degenerative changes in disc and facet
Type 3 - Degenerative
Type of spondylolisthesis secondary to severe injury that fractures any part of the vertebrae other than the pars interarticularis
Type 4 - Traumatic
Type of spondylolisthesis secondary to a general disease such as a tumor
Type 5 - Pathologic
Spondylo means what in Greek
Vertebra
Listhesis means what in Greek
To slide on an incline
What is spondylolysis
When the pars fractures completely
0-25 % slipped
Grade 1
25-50% slipped
Grade 2
50-75% slipped
Grade 3
75-100% slipped
Grade 4
Spondyloloptis (vb falls off the anterior edge of the vertebral body below)
Grade 5
What are radicular symptoms
Numbness, tingling, weakness, and/or paresthesia
Radicular symptoms typically correspond to what?
A dermatome
What do myelopathic symptoms typically indicate?
Impingement of spinal cord
What are myelopathic symptoms?
Gait disturbances, bowel and bladder dysfunction, and or/generalized weakness
Pain that is felt in the back itself
Axial back pain
Theory as to why axial back pain occurs
Chemicals formed in the disc during degenerative process has irritated the sinuvertebral nerves
Uses radiation to create a picture of the tissues of the body
Radiography
Uses a computer to compile multiple views of the body
CT scan
Uses magnets and radio waves to create an image based on water content of the tissues
MRI (magnetic resonance imaging)
When radiopaque die is injected into multiple discs and the patient is prompted to notify the surgeon if they are experiencing concordant pain
Discography
Can be used to assess disc height, volume of intervertebral foramen, osteophytes and changes to endplate
Radiograph
Allows surgeon to assess patency (openness) of the vertebral and intervertebral foramina as well as condition of facet joints
CT Scan
Allows surgeon to examine the health and water content of discs
MRI
First step in treating DDD
Conservative therapy
Success rate for treating severe lumbar radiculopathy with conservative therapy
50%
% of back pain patient who never need surgery
90%
Removal of bone or soft tissue putting pressure on neural elements
Decompression
Physically removing the pieces of tissue that are exerting pressure onto a neural element
Direct decompression
Increasing the amount of room for the neural structures by increasing or restoring the height of the disc space
Indirect decompression
A procedure that increases the diameter of the intervertebral foramen
Foraminotomy
A procedure in which sections of the lamina and the facet are removed
Foraminotomy
Indications for foraminotomy
Radiculopathy caused by pressure on spinal nerve by disc herniation or osteophytes
Advantages of foraminotomy
Decompress neural elements without fusion, relief of cervical radiculopathy in 90% of patients
Disadvantages of foraminotomy
Not effective for myelopathy or pathology toward midline
May lead to spinal instability
Removal of part of the lamina to relieve compression on a neural element or to gain access to other anatomical structures
Laminotomy
Often done in conjunction with a foraminotomy, microdiscectomy, or posterior lumbar interbody fusion
Laminotomy
Indications for laminotomy
Herniated disc, compressed nerve root
Advantages of laminotomy
allows access to neural elements and disc from a posterior approach
Disadvantages of laminotomy
Not often a stand alone procedure
A procedure that involves the removal of the herniated portion of a disc, performed through a small incision, usually with the assistance of a microscope to enhance visualization
Microdiscectomy
Indications for microdiscectomy
Lumbar disc herniation with radicular symptoms or cauda equina syndrome
Advantages of microdiscectomy
Minimally invasive, small incision, no fusion
Disadvantages of microdiscectomy
Simply removes herniation, does not repair the disc or restore lost height of the disc
A procedure in which the lamina is removed
Laminectomy
Commonly performed to decompress the spinal cord
Laminectomy
Indications for laminectomy
Spinal stenosis
Advantages of laminectomy
Increases volume of vertebral foramen
Disadvantages of laminectomy
May destabilize the spine if performed over multiple levels, requiring instrumentation
Contraindications for laminectomy
Contraindicated if kyphotic deformity is present
A procedure that involves reshaping the lamina to increase the volume of the vertebral foramen and decompress the spinal cord without removing the protective function of the lamina
Laminoplasty
Indications for laminoplasty
Cervical and upper thoracic spinal stenosis
Advantages of laminoplasty
Increases the volume of the vertebral foramen over multiple levels without removing the protective function of the lamina or significantly destabilizing the spinal segment
Disadvantages of laminoplasty
Technically more demanding than a laminectomy and limited to cervical and upper thoracic spine
Contraindications for laminoplasty
Contraindicated if spine is in kyphosis
Removal of the disc
Discectomy
Inducing the body to grow a bridge of bone from one vertebra to another
Fusion
Five basic steps of discectomy and fusion
Removal of disc Placement of spacer in disc space Graft Augmentation Stabilization Fusion
This device attempts to achieve the goals of a fusion (decompression, relief of symptoms) while maintaining motion at the spinal segment
Disc replacement
Comprised of spinal instrumentation that may allow for controlled flexion, extension, lateral bending, and axial rotation while resisting unwanted shear motion of the spinal segment
Dynamic stabilization
Limit extension in patients suffering from spinal stenosis
Interspinous spacer
Replaces a diseased, painful facet
Facet replacement
