Chapter 43 Overview of Low Back Pain Disorders Flashcards
1
Q
Pain originating from the spine usually manifests as
A
pain in the low back and neck, and infrequently as pain in the upper lumbar and mid back areas.
2
Q
Spinal pain (SP) can be grouped into three broad categories:
A
acute pain when the pain duration is between 2 to 4 weeks; subacute pain when the pain persists for up to 12 weeks; chronic pain, when the pain continues for more than 12 weeks
3
Q
The risk factors associated with SP have been classified into three broad categories:
A
biomechanical, psychosocial,
and personal.
4
Q
The biomechanical risk factors of spinal pain
A
are determined by spinal loading, and typically include parameters such as physical stress and the asymmetry of physical tasks
5
Q
The psychosocial risk factors of spinal pain
A
pertain to psychogenic stress and are often related to job satisfaction,
responsibility, and variety
6
Q
Personal risk factors of spinal pain
A
have
been acknowledged as physical, familial, anthropometric,
gender, and personality traits
7
Q
The following risk factors have been associated with the development of spinal pain:
A
- Jobs that are stressful and that require heavy lifting and use of heavy equipment
- Cigarette smoking
- Psychiatric, emotional, and personality issues
- Obesity
- Spinal deformities and endplate injury
- Genetic predisposition
- Peripheral vascular disease
8
Q
The human vertebral column consists of
A
7 cervical, 12 thoracic,
5 lumbar, 5 sacral, and 3 to 5 coccygeal vertebrae.
9
Q
comprise a vertebral motion segment
A
two adjacent vertebral bodies and an intervening
intervertebral disc
10
Q
The linear array of adjacent spinal motion segments
forms the continuum of the spinal column that houses dorsally the
A
neural elements of spinal cord and nerve roots of
the cauda equina.
11
Q
nerve roots of the cauda equina are encompassed dorsally and laterally by
A
the neural arch
12
Q
Components of neural arch
A
comprised of spinous
processes, spinal laminae and the ligamenta flava posteriorly, and pedicles and intervertebral foraminae laterally
13
Q
In addition to the linkage of the vertebral bodies by intervertebral discs, the adjacent vertebral bodies are articulated
A
dorsally by a pair of synovial joints, the zygapophysial or
facet joints.
14
Q
The most significant of the spinal ligaments
include
A
the anterior and posterior longitudinal ligaments
and ligamentum flavum
15
Q
The incredible forces applied to the spinal column are transmitted to the lower extremities by
A
two large synovial-fibrous joints, the sacroiliac joints
16
Q
The vertebral bodies are largely composed of
A
cancellous bone housed in a thin layer of cortical bone.
17
Q
*The intervertebral discs (IVDs) are made of
A
annulus fibrosus (AF), nucleus pulposus (NP), and vertebral endplates
18
Q
*Distinction of annulus fibrosus (AF) and nucleus pulposus (NP)
A
Both the NP and AF are populated by sparsely present cells immersed in abundant intercellular matrix. Cells populating the NP are found in clusters and are chondrocyte-like,
whereas the cells found in AF have fibrocytic features.
19
Q
*Distinction of annulus fibrosus (AF) and nucleus pulposus (NP) Matrix
A
NP matrix is jelly-like, and is made of high concentration of water and proteoglycans, whereas matrix constituting AF is high in collagen arranged in the form of interlacing lamellae. These collagenous lamellae are firmly attached to the adjacent vertebral bodies and are most dense anteriorly.
20
Q
*Although the cancellous vertebral bodies and the spinal canal contents are highly vascular, the IVDs are mostly
A
avascular and the largest avascular structure in the body. The normal NP and inner third of the AF completely lack any vasculature; moreover, the avascular cartilaginous endplates act as a barrier separating
the vertebral body vasculature from the IVD contents
21
Q
*Innervation of the IVDs and the neural canal contents is mainly by
A
nerve plexuses along the anterior and posterior longitudinal ligaments. The nerve plexus along the posterior longitudinal ligament receives its
input mainly from the sinuvertebral nerve and the gray rami communicans, while the plexus along the anterior longitudinal ligament is contributed to mainly by the gray rami communicans
22
Q
*The sinuvertebral nerve originates from
A
the segmental spinal nerve as it exits the intervertebral foramen; it re-enters the vertebral canal and contributes mostly to the posterior longitudinal plexus. it also receives contribution from the gray rami communicans.
23
Q
*The posterior longitudinal ligament plexus innervates
A
the ventral half of the vertebral column, including the anterior dura and posterior intervertebral discs.
24
Q
*The gray ramus communicans nerve emerges from
A
the spinal segmental nerve; soon after, it enters the intervertebral
foramina and runs anteriorly along the inferior third of the
vertebral body.
25
*The gray ramus communicans nerve connects to the
sympathetic trunk before branching into lateral and anterior branches to innervate the lateral and anterior disc annulus of the disc levels above and below
26
The posterior primary ramus, soon after its division from the anterior primary ramus, branches into
medial and lateral branches
27
The medial branch of the posterior primary ramus supplies
most dorsal spinal column components, including facet joints, posterior neural arch components, and spinous processes
28
The annulus fibrosus (AF) of the intervertebral
| discs (IVD) has complex innervation from several sources and multiple spinal segments, including contributions from the
sinuvertebral nerves, segmental spinal nerve, gray ramus communicans nerve, and the sympathetic trunk; thus, a normal IVD has rich autonomic connections
29
the pain receptors—
| mostly mechanoreceptors—are found mainly
in the spinal ligaments, paraspinal muscles, vertebral body periosteum, and the outer third of the AF and facet joints
30
The flexibility and remarkable range of motion exhibited by an active spine depend almost entirely on
the cumulative plasticity
| exhibited by the individual IVDs
31
the plasticity of IVD
The individual IVD is only moderately plastic and the NP, like the vertebral body, is practically incompressible due to its high water content. The compressive forces applied to the IVD are borne by the NP and are distributed equally to
the AF as a tensile force
32
NP incompressibility is maintained almost exclusively
| by the
hydrostatic pressure generated by its proteoglycan content, which is a function of intricate metabolic processes.
33
Being mostly avascular, IVD obtains metabolic
| requirements almost exclusively by
diffusion from capillary
plexuses in adjacent vertebral bodies and the outer AF.
Discal catabolic activities are in addition facilitated by
discal matrix metalloproteinases (MMPs)
34
Dysfunction and decline in the viable NP cells, enhanced MMP activity, and increased disc cytokines and proinflammatory mediator concentration can start a vicious cycle that can reduce
NP proteoglycan and water content and consequent loss
| of disc hydrostatic pressure
35
The ensuing laxity of the NP
| exposes the AF to
direct compressive forces
36
Thecumulative effect of increased AF stress and collagen loss may lead to
eventual AF failure with the consequent development
| of annular tears and fissures
37
Structural changes within the IVD alter its biomechanical properties and cause it to
shrink and become less plastic.
These changes in the IVD dynamics increases stress on
adjacent vertebral motion segment and may propagate
degenerative changes in several contiguous spinal structures.
38
degenerative changes in several contiguous spinal structures
sclerosis and hypertrophic
new bone formation in adjacent vertebral bodies---Modic changes, accelerated degenerative changes in the adjacent IVDs, hypertrophy and arthritis of the facet joints, sacroiliac joint dysfunction, and paraspinal myofascial syndrome.
39
Hypertrophic changes in the discs, facet joints and ligamenta flava may leads to
narrowing of the spinal canal and the intervertebral foraminae. These stenotic changes may cause symptoms from compression of the spinal cord and the spinal nerve roots
40
Etiology of Mechanical Spinal Pain
- Herniated discs
- Spondylosis or degenerative disc disease
- Discogenic pain, internal disc disruption, or annular tears
- Spondylolisthesis or displacement of one vertebral body over the other
- Spondylolysis or defect in pars interarticularis without the vertebral slippage
- Spinal instability or anomalous movement between the contiguous vertebral bodies
- Foraminal stenosis or skeletal hypertrophy causing symptoms of nerve root compression
- Spinal canal stenosis or neurogenic claudication or myelopathic symptoms and signs
- Facet arthropathy
- Musculoligamentous strains or sprains
- Myofascial pain syndrome
- Congenital spinal conditions such as kyphosis or scoliosis
41
Etiology of Nonmechanical Spinal Pain
- Primary and metastatic neoplasms of the spine or its neural contents
- Infections, such as osteomyelitis of the vertebral bodies, septic discitis, paraspinal or epidural abscess
- Noninfectious inflammatory spinal disorders such as ankylosing spondylitis, Reiter’s syndrome, psoriatic spondylitis, and inflammatory bowel disease
- Traumatic or pathologic fractures such as vertebral body compression fractures and dislocations
- Metabolic disorders of the spine such as Paget’s disease
- Miscellaneous conditions such as Scheuermann’s disease or
osteochondrosis, and hemangiomas
42
Etiology Referred or Visceral Spinal Pain
- Pelvic visceral disorders such as prostatitis, endometriosis, or pelvic inflammatory disease
- Renal disease such as nephrolithiasis, pyelonephritis, or perinephric abscess
- Vascular disease such as abdominal aortic aneurysm
- Gastrointestinal disease such as pancreatitis, cholecystitis, or
perforated bowel
43
Mechanical SP
is ubiquitous and may be defined as pain emanating from the benign degenerative conditions afflicting the various spinal structures, such as IVDs, facet joints, and the neural
elements, or the immediately adjacent paraspinal structures,
such as muscles, ligaments, periosteum and blood
vessels.
44
range of terms used to
| describe mechanical SP
lumbago, spondylosis,
segmental or somatic dysfunction, ligamentous strain,
subluxation, and facet joint, sacroiliac, or myofascial
syndromes.
45
A detailed history of SP patient should note the following
- Location and any radiation of pain, especially in the dermatomal distribution
- Characteristics of pain, such as burning, lancinating, or aching quality
- Severity of pain, especially patient’s ability to function and to sleep at night
- Circumstances of onset of pain such as history of trauma
- Factors aggravating and relieving the pain
- Patient’s age
- Presence of any constitutional symptoms such as fever, malaise, or weight loss
- Special pain features such as night pains, bone pain, morning stiffness, and history of claudication
- Neurologic symptoms such as numbness, tingling, and weakness, along with any bowel or bladder dysfunction; especially urinary retention and urinary or fecal incontinence
- History of any previous treatments and their efficacy
- Patient’s detailed past medical and surgical history
- Assessment of social and psychological factors that may affect patient’s pain
- Functional impact of pain on patient’s work and activities of daily living
46
A comprehensive general physical and a detailed neurologic examination should be performed in all the patients with SP. Specific spinal examination should include:
l Assessment of gait.
l Range of spinal motion.
l Determination of local spinal and paraspinal tenderness.
l Specific tests for the clinical diagnosis of various SP
syndromes, including those for nerve root irritation, facet syndrome, and sacroiliac joint dysfunction
47
“Red Flags” in Patient’s Clinical Evaluation
guidelines to recognize clinical features that would signify the presence of conditions such as fractures, tumors, and infections that can pose significant threat to life or neurologic
function
Age50 years
Symptoms over 3 months indicate a less serious
etiology
History of significant traumatic injury, or mild
trauma in an elderly patient or in a patient with a serious medical condition
Presence of constitutional
symptoms: Fever, chills, malaise, night sweats, unexplained weight loss,
History of cancer, recent bacterial infections,
intravenous drug abuse, immunosuppression,
organ transplantation, and corticosteroid use are at higher risk for pathologic fractures, epidural and vertebral body abscesses, and metastasis.
Pain not relieved with rest, supine position, and analgesics suggesting a a serious pathologic conditions
Presence of cauda equina
syndrome
48
cauda equina syndrome etiology
Caused by acute compression of the spinal cord or the nerve roots of the cauda equina. caused by massive midline disc herniation or rarely by spinal metastases, hematoma, epidural abscess, traumatic compression, acute transverse myelitis, and abdominal aortic dissection.
49
cauda equina syndrome symptoms
Symptoms include bilateral, but often unequal, lower extremity radicular pains and weakness, gait disturbances, abdominal discomfort and overflow incontinence.
50
cauda equina syndrome physical examination
Physical examination
exhibits neurologic dysfunction, saddle anesthesia, diminished anal sphincter tone, and urinary bladder retention. In addition to the positive findings on neurologic examination, the patient’s physical examination typically exhibits saddle
anesthesia—diminished sensation in the buttocks and perineum—diminished anal sphincter tone, and the evidence of urinary bladder retention.
51
cauda equina syndrome diagnosis and treatment
Due to the possibility of spinal cord compression at higher levels, dx must be made by imaging the entire spine. Treatment is urgent decompressive surgery in order to reduce permanent neurologic disability
52
In general, patients with benign mechanical SP should have pain mainly with
spinal movements such as sitting, bending, lifting, or twisting, and the pain should improve over the course of few days to weeks.
53
Why is age a red flag?
Patients less than 20 or over 50 years of age are suspect, as younger patients have a higher incidence of congenital and developmental anomalies, while older patients have a greater likelihood of neoplasms, pathologic fractures, serious infections, and life-threatening extraspinal pathologic conditions.
54
as SP conditions are commonly self-limiting and benign, in the absence of “red flags” in the clinical history, diagnostic testing
is not recommended for SP of less than 4 to 6 weeks
55
Plain radiography allows evaluation of
the bony spinal anatomy. It can reliably diagnose pathologic spinal lesions such as fractures, deformities, transitional vertebra, and spondylolisthesis.
56
Subtle spinal abnormalities seen on plain radiography
lumbar lordosis, disc space narrowing, arthritic changes, ossification of the vertebral end plates, and abnormal range of spinal movements or spinal instability
57
Major drawbacks of plain spinal radiography
inability to visualize the soft tissue structures and
| their abnormalities, such as herniated disc, neural element compression, and soft tissue neoplasms.
58
Traditional plain radiography sequences includes
Anteroposterior (AP), lateral, and oblique views.
59
In the AP view indicators of normal spinal morphology include
vertical alignment of the spinous processes, smooth undulating borders created by lateral masses, and uniformity among the disc spaces.
60
Misalignment of the spinous processes
| suggests a
rotational injury such as unilateral facet dislocation
61
The AP view of the lumbar spine should include
the entire pelvis to allow the assessment of acetabulum and femoral heads and the lower portion of the thoracic spine due to the high occurrence of injury between T12 and L2 spinal levels.
62
The lateral views provides
| a superior image of the
vertebral bodies, facet joints, lordotic spinal curvature, disc space height, and spondylolisthesis.
63
Oblique views, taken with the x-ray tube angled at (45 degrees), provide
enhanced views of the neural foraminae and pars interarticularis. These views best demonstrate foraminal abnormalities and spondylosis
64
Flexion-extension views
| are typically used to
demonstrate spinal instability as a cause of chronic pain. However, these views can also be used in trauma patients to assess ligamentous injury.
65
Bone scintigraphy creates images by
scanning for the presence of radiographic compounds such as technetium-99m phosphate or gallium-67 citrate
66
Bone scintigraphy vs. plain radiography
| and computerized and magnetic resonance
plain radiography and computerized and magnetic resonance scanning reveals simple morphologic changes, bone scintigraphy detects biochemical osseous processes and is valuable when clinical findings are suspicious of spinal osteomyelitis, neoplasms, or occult fracture
67
Primary spinal tumors, that are typically benign and show as active lesions on bone scintigraphy
osteoid osteoma, osteoblastoma, aneurysmal bone
| cyst and osteochondroma
68
on Bone scintigraphy Osseous spinal metastases typically appear as
multiple foci of increased tracer uptake that are asymmetrically scattered
69
What pathology yield a negative bone scan
aggressive bony tumors, such as myeloma, that does not invoke an osteoblastic response
70
Lesions affecting the pedicles and facet joint lesions
Lesions affecting the pedicles are typically malignant, while facet joint lesions are apt to be benign
71
Bone scintigraphy with the addition of single-photon
| emission computed tomography (SPECT) provides
a three-dimensional spinal image and enhanced topographic tumor location
72
SPECT has been used to distinguish
benign from malignant osseous neoplasms
73
Computed tomography (CT) uses radiologic data to
generate contiguous, overlapping axial images of the scanned area.
74
Spinal CT is most useful in evaluating
osseous details of the spine in an axial plane particularly the facet joints and the lateral recesses. It is most valuable in diagnosing fractures, tumors involving the spine, and in showing the relative position of one osseous structure to another, such as partial or complete dislocations and spondylolisthesis
75
The resolution of the soft tissue structures on spinal CT is inferior to
magnetic resonance imaging (MRI). The routine use of spinal CT for the diagnosis of the soft tissue intraspinal canal lesions is therefore discouraged.
76
Spinal CT cannot reliably distinguish between
herniated IVD and epidural scar tissue and amongst various spinal canal lesions such as neoplasms of the spinal cord or the nerve roots.
77
substitute when MRI is contraindicated
CT myelogram
78
significant limitation of spinal CT
motion artifact- the ensuing indistinct images and the chance of imprecise diagnosis of
less distinguishing lesions, such as nondisplaced fractures.
Radiation exposure is another significant hazard that limits the extent to which spinal CT can be employed.
79
Spiral CT reduces
exposure time, radiation hazard and motion artifact.
80
Three-dimensional CT
provides higher resolution three dimensional images of the spine. This modality is currently being used only for complicated spinal problems such as failed back surgery syndrome.
81
How an image of various soft tissues created
powerful magnetic fields generated in the MRI scanner align the water molecules or protons, constituting the bulk of the body mass, in the direction of the magnetic fields applied. Brief bursts of radiofrequency (RF) waves are then applied and the resulting electromagnetic
fields alter the proton alignment. Cessation of the RF field results is the protons decaying to their original state and releasing energy as photons, which are detected by the MRI scanner. The protons in the various tissues return to the equilibrium state at dissimilar rates and an image of various soft tissues is therefore created.
82
the contrast between the various body tissues can be altered in MRI
By changing timing of the various scanner sequences, like the echo time (TE) and the repetition time (TR)
83
T2 weighted images use
a spin echo (SE) sequence, with long TE and long TR intervals, and the water-containing
tissues appear, whereas while fat-rich or water-deprived tissues appear dark.
84
T1 weighted images use
a gradient echo (GRE) sequence, with short TE and short TR sequencing, and the tissue contrast on T1 weighted images is the opposite of the T2 weighted images.
85
cerebrospinal fluid image on T1 weighted images and on T2 weighted images
cerebrospinal fluid appears dark on T1 weighted images,
| and it appears white on T2 weighted images
86
IVD image on T1 weighted images and on T2 weighted images
On T1 weighted images a normal IVD appears dark and homogenous, whereas it appears brighter on T2 weighted images—the NP with its greater water content appears brighter than the AF.
87
considered the gold standard in spinal imaging
Although high quality osseous images can be achieved with spinal CT, MRI is currently considered the gold standard in spinal imaging.
88
Why MRI is superior to spinal CT?
MRI provides sharper distinction between the various soft tissues, and the overall soft tissue
resolution is superior. MRI offers excellent images of the spinal canal and its neural contents, the neural foraminae and the exiting nerve roots, and the disc spaces and its contents. MRI also allows evaluation of complete spine in various planes.
89
when greater distinction between various soft
tissues is required, such as differentiation between scar tissue and recurrent IVD herniation in patients with a history of previous spine surgery
A contrast enhanced MRI can be performed
90
Spinal CT and MRI uses what radiopaque contrast agents
in contrast to spinal CT, which uses radiopaque contrast agents such as iodine or barium comprised of higher atomic weight elements than the surrounding tissues, MRI uses contrast agents such as gadolinium and manganese that enhance tissue resolution by their paramagnetic properties
91
Limitations of MRI
lengthy examination time, claustrophobia, and its effects on metallic objects
92
MRI is contraindicated
in the presence of ferromagnetic implants, such as cardiac pacemakers, intracranial aneurysm
clips, mechanical heart valves, and intraocular foreign bodies.
93
Metallic stabilization in MRI
Metallic stabilization devices used in spinal
| surgery cast artifacts and may render spinal imaging almost unattainable.
94
Electrodiagnostic studies encompass the following:
Electromyography (EMG)
Nerve conduction studies (NCV)
Evoked potentials
The studies are useful in localizing the pathologic lesion, determining the extent of the neural
injury, predicting the course of recovery, and in determining whether the radiologic abnormalities observed are the likely source of patient’s symptoms
95
Electromyography (EMG)
Study of spontaneous or evoked skeletal muscle electrical activity
96
Nerve conduction studies (NCV)
Study of conductive abilities of the motor and sensory nerves
97
Evoked potentials
Study of brain electrical activity evoked from various nervous system locations, such as somatosensory-evoked potentials (SSEPs) and motor evoked potentials (MEPs).
98
Electrodiagnostic studies useful when the
clinical evaluation is inconclusive in distinguishing between radicular and peripheral neuropathic symptoms.
99
Screening for nonphysical factors is crucial in the management of SP patients
Psychological, occupational, and socioeconomic factors can complicate both the assessment and the treatment of SP patients
100
variety of other diagnostic and laboratory tests
complete blood count (CBC), urine analysis (UA),
erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RH-factor), anti-nuclear antibodies (ANA) and HLA-B27 antigen, are useful when nondegenerative conditions, such as tumors, infections, and rheumatologic disorders, are considered a cause of SP
101
Noninvasive Treatments for Spinal Pain
Rest (continuation of daily activities and early return to work has been reported to shorten the chronic disability and duration of work absence), Pharmacologic therapy, Physical therapy, Acupuncture, Spinal manipulation
102
Pharmacologic therapy for Spinal Pain
```
Nonsteroidal anti-inflammatory drugs
Narcotics
Muscle relaxants
Corticosteroids
Calcitonin (beneficial
for pain ensuing from spinal stenosis caused by Paget disease)
```
103
Physical therapy for Spinal Pain
```
Body mechanics, ergonomics, posture
awareness, and activities of daily living
(ADL) training
Strengthening and stretching exercises
Organized functional training programs
Therapeutic massage
Joint mobilizations and manipulations
Mechanical traction
Biofeedback
Electrical muscle stimulation
Transcutaneous electrical nerve stimulation (TENS)
Application of superficial and deep thermal modalities
Cryotherapy
Work hardening
```
104
Minimally Invasive Treatments for Spinal Pain-
| Injection therapy
- Epidural steroid injections
- Facet joint injections
- Sacroiliac joint injection
- Trigger pain injections
105
Minimally Invasive Treatments for Spinal Pain-
| Neuroablative procedures
- Chemical neurolysis
- Cryoablation
- Radiofrequency ablation
106
Minimally Invasive Treatments for Spinal Pain-
| Intradiscal procedure
Discography
Percutaneous disc decompression
Intradiscal electrothermal therapy
Intradiscal bioculoplasty
107
Spinal Surgery for Spinal Pain- Decompression surgery
```
Discectomy
Microdiscectomy
Endoscopic discectomy
Decompression for fixed osseous
stenosis
```
108
Spinal Surgery for Spinal Pain- Fusion
```
Anterior fusion
Posterior fusion
Circumferential fusion
Transforaminal lumbar interbody
fusion
```
109
Spinal Surgery for Spinal Pain- Disc arthroplasty
SB Charite III
ProDisc
Maverick
Flexcore
110
The treatment goals of various physical therapy modalities
| include:
```
l Pain relief
l Reduction in muscle spasm
l Improved range of spinal motion (ROM)
l Improved strength
l Postural correction
l Improvement in functional status
```
111
Biofeedback Treatments
entails external feedback, which translates
physiologic muscle activity (often using EMG) into visual or auditory signals that help the patient reduce muscle tension and pain
112
Disc decompression surgery is typically reserved for patients with
a herniated IVD, with distinctive symptoms
of persistent radicular pain, positive straight leg raise test, and the imaging studies confirming the presence of herniated IVD
113
discectomy involves
the procedure in essence involves laminectomy or laminotomy, release of ligamentum flavum, removal of the herniated disc fragments, and a vertical annulotomy for the removal of nonherniated disc material.
114
In older patients the nerve root compressive symptoms are often the result of
local degenerative changes involving the disc, facet joints, and the local ligaments. Such changes may include disc bulges and herniations, facet and ligamentous hypertrophy, osteochondral spurs, and spondylolisthesis.
115
Common indications, for spinal fusion surgery
| include
ensuing instability after decompressive spinal
surgery and diverse causes of mechanical SP such as spondylolysis, spondylolisthesis, degenerative arthritis, spinal instability, discogenic pain and scoliosis
116
During the spinal fusion surgery
the dysfunctional spinal motion segments—including the incriminating disc and the
painful degenerative joints—may be resected and the spine is characteristically rigidly stabilized by using various mechanical fusion devices such as pedicular screws interpedicular fixation plates, and intervertebral spacers such as cylindrical cages
117
Mechanical spinal instrumentation, however, is subject to fatigue failure and eventual fracture unless
osseous spinal fusion is attained by osteogenesis, classically by the use of bone graft in the
vascularized tissue bed.
118
The key elements required for spinal osteogenesis include
precursor cells capable oftransformation into bone-forming osteoblasts, osteoconductive materials that would serve as scaffolds for the formation of new bone, and osteoinductive growth factors that will promote differentiation of progenitor cells into
osteoblasts.
119
In spinal fusion gold standard osteogenetic material
Autologous bone graft remains the gold standard osteogenetic material because it contains all three essential elements (osteoblasts, osteoconductive materials, and osteoinductive growth factors.
120
Limitations of autologous bone graft
the amount of available graft material and the morbidity associated with harvesting autologous bone graft.
121
other osteogenetic materials including bone graft extenders
demineralized bone matrix, calcium carbonate,
hydroxyapatite-tricalcium phosphate, bone graft substitutes, and, more recently, osteoinductive substitutes, such as recombinant human bone morphogenic protein (BMP).
122
Disadvantage of Spinal Fusion
spinal fusion surgery remains a salvage procedure, as it reduces spinal mobility and increases stress and consequently degeneration at adjacent spinal levels.
123
Describe Disc Arthroplasty and difference to fusion
During disc arthroplasty the offending disc is surgically removed and replaced by an artificial disc. When compared to spinal fusion, the major benefit of disc replacement surgery
include preservation of spinal range of motion and decreased adjacent spinal segment degeneration
124
The primary indication for disc arthroplasty
recalcitrant disabling LBP secondary to discogenic disc disease, which is confirmed by MRI and discography.
125
Contraindication for disc arthroplasty
The exclusion criteria include evidence of nerve root compression, facet, and sacroiliac joint arthropathy.
126
types of artificial discs for disc arthroplasty
B Charite III, ProDisc, Maverick, and Flexcore. SB Charite III consists of two cobalt-chrome endplates, with a sliding polyethylene core. The endplates are anchored to the vertebral bodies by teeth and later by the bony in-growth
127
Spinal reconstruction is contemplated when the
disease progression either destroys the structural integrity of the spine or produces deformity that alters its normal biomechanics
128
The principles of spinal reconstruction surgery
| include
resection of diseased tissues, soft tissue, and
bony release to allow spinal realignment and rigid fixation to maintain spinal stability until the biologic fusion is achieved. Proper spinal realignment must restore the physiologic lumbar lordosis and thoracic kyphosis. An appropriate graft or implant length must be selected to maintain this sagittal balance.
129
Conditions requiring spinal reconstruction surgery
| may include
traumatic spine injuries, spinal infections and tumors, and spinal deformities such as scoliosis and kyphosis. adverse consequences of failed prior spinal surgery are a major cause of spinal reconstruction
surgery
130
Spinal reconstruction typically
| involves
anterior release in the form of vertebral body
| (corpectomy) and disc (discectomy) resection and posterior release that incorporates chevron osteotomies.
131
Once the spinal segment is appropriately realigned it must be
rigidly fixed to maintain the alignment, until the successful osseous fusion is achieved
