9. Aggrecans – side chains
negative charged, hydrophilic
Replaced by non aggregated
glycoproteins in ageing
Anabolic and catabolic
process in dynamic state
Disrupted in degeneration
19. POSTERIOR TENSION BAND
• A combination of osseous and
ligamentous structures
• including the supraspinous
ligaments, interspinous
ligaments, articular facet
capsules, and ligamentum flava
26. TYPES OF INSTABILITY
Overt instability is defined as
the inability of the spine to
support the torso during
normal activity.
Limited instability is defined
as the loss of either ventral
or dorsal spinal integrity with
preservation of the other,
which is sufficient to support
some normal activities
28. • Glacial instability
• is defined as spinal instability that is not
overt and that does not pose a significant
risk for the rapid development or
progression of kyphotic, scoliotic, or
translational deformities; however, like the
motion of a glacier, the deformity progresses
gradually, although substantial external
forces do not cause immediate movement or
progression of deformity
36. ENDPLATE CHANGES
Loss of vascularity
Cartilage disorganisation
Microfractures in subchondral bone
New bone formation with sclerosis of endplate
37.
38. SPONDYLOSIS
Progressive pathologic process
Disc degeneration, facet arthropathy,
hypertrophy and calcification of Posterior
Longitudinal Ligament and Ligamentum Flavum
Ligament laxity
Capsule laxity
Biomechanical stress on endplates and
uncovertebral joints – osteophyte formation
39. BIOMECHANICAL CHANGES
Loss of lordosis
Force vector shifted anteriorly, more
stress on disc posteriorly leading to
posterior disc bulge
Mobility of spine – increased initially,
then decreased
44. BIOMECHANICS
OF FSU
Neutral zone – smaller loads result
in larger displacements
Elastic zone – larger loads result in
smaller displacements
NZ + EZ = ROM
ROM of FSU increases up to grade 3
of degeneration, then decreases
46. NEURAL INJURY AT MOLECULAR LEVEL
Oligodendrocytes more vulnerable
Apoptosis – inflammation mediated
Antiapoptotic agents use – antioxidants – controversial
Methyl pred – antiapoptotic action
Cystic cavitation, gliosis, axonal dropout, Wallerian degeneration
47. Spinal Canal
Stenosis
Sagittal diameter less than 12 mm
Pavlov's ratio less than 0.8
Dynamic compression due to pincer phenomenon
Kyphosis – can produce sagittal bowstring effect
Dynamic effects – increased axolemmal permeability, disruption of
axoplasmic flow, deformed sodium channels with pathological
calcium influx
48. SPINAL CORD ISCHAEMIA
• Compression of radicular
arteries
• Compression of venous plexus
• Compression of perforating
arteries
• AP flattening – early ischaemia
to anterior corticospinal tracts
53. RADIOLOGY
• Bulging
• PROTRUSION
• - described as localized (more than 25%
of the circumference of the disc)
displacement of disc material and the
distance between the corresponding
edges of the displaced portion must not
be greater than the distance between
the edges of the base of the displaced
disc material at the disc space of origin
54. EXTRUSION
• is a herniated disc in
which, in at least one
plane, any one distance
between the edges of
the disc material beyond
the disc space is greater
than the distance
between the edges of
the base of the disc
material beyond the disc
space in the same plane
or when no continuity
exists between the disc
material beyond the disc
space and that within
the disc space
55. Extrusion
Types
Extrusion with sequestration is a
focal disc displacement when
extruded disc material that has
no continuity with the disc of
origin
2 types – subligamentous and
transligamentous
72. ROLE OF CT
the bony anatomy
determining whether compressive
pathology is soft or hard
Identifying the presence of ossification of
the posterior longitudinal ligament (OPLL)
Assessing spondylosis in the facet joints or
auto-fusions
73. NCS AND
EMG
Guideline:
EMG needle examination:
a) needle examination of at least 1 muscle innervated by C5, C6, C7, C8 and T1 spinal roots in a symptomatic limb
b) cervical paraspinal muscles at 1 or more levels (except in patients with prior posterior approach cervical surgery
c) if abnormalities are identified, perform studies of 1 or 2 additional muscles innervated by the suspected root and different
peripheral nerve
2. Guideline:
At least 1 motor and 1 sensory nerve conduction study (NCS) in the clinically involved limb to determine if there is
concomitant polyneuropathy or nerve entrapment. Motor and sensory NCS of median and ulnar nerves if symptoms and signs
suggest CTS or ulnar neuropathy. If 1 or more NCS are abnormal or if clinical features suggest polyneuropathy, further
evaluation may include NCS of other nerves in the ipsilateral and contralateral limb
74. Suspected
cases….
• sensitivity of 50-71% for the needle EMG
examination and correlation between
positive needle EMG and radiologic
findings of 65-85%.
75. Radiculopathy
…conservative
• 90% of patients can improve without
surgeryand regression of an extruded
cervical disc has been demonstrated
radiographically by CT and MRI.
• The recovery period may be made more
tolerable by adequate pain medication, anti-
inflammatory medication (NSAIDs or short-
course tapering steroids) and intermittent
cervical traction (e.g. gradually escalating
up to 10–15 lbs. for 10–15 minutes, 2–3
×daily).
76. Conservativ
e
managemen
t
1. physical therapy, which may also include
cervical traction.
2. Interventional pain management
a) Trigger point injections
b) Facet blocks
c) Epidural steroid injection: not used as
often and with lumbar spine
77. Indications
for surgery
those that fail to improve
those with progressive neurologic deficit while
undergoing non-surgical management
Management of central cord syndrome associated with
acute cervical disc herniation is controversial, since the
natural history is favorable in most cases. However, some
patients have poor recovery and experience permanent
deficits even with emergency surgery
78. Surgical options
• 1. anterior cervical discectomy +/- Corpectomy
• a) without any prosthesis or fusion: rarely used today
• b) combined with interbody fusion: the most common approach
• ● without anterior cervical plating
• ● with anterior cervical plating or with zero profile
• c) with artificial disc AKA cervical disc arthroplasty
• 2. posterior approaches
• a) cervical laminectomy: not typically used for a herniated cervical disc, more common for
cervical
• spinal stenosis, OPLL
• ● without posterior fusion
• ● with lateral mass fusion
• b) keyhole laminotomy: sometimes permits removal of disc fragment
79. Indications for
spine
stabilisation
(1) to restore clinical stability to a spine in which
the structural integrity has been compromised
(2) to maintain alignment after correction of a
deformity
(3) to prevent progression of a deformity
(4) to alleviate pain
80. Advantages
of fusion
maintenance of cervical lordosis
indirect decompression by increasing foraminal
dimensions
prevention of recurrent spondylosis or neural
compression at the operated level and stabilization of the
operated level to prevent progressive spondylosis in the
posterior elements (osteophytes from the superior
adjacent process)
81. ACDF
Usually used for C3 – C7 levels
Advantages over posterior (nonfused) approach:
1. safe removal of anterior osteophytes
2. fusion of disc space affords immobility (up to 10%
incidence of subluxation with extensive posterior approach)
3. only viable means of directly dealing with centrally
herniated disc
82. Disadvantages over posterior approach
immobility at fused
level may increase
stress on adjacent disc
spaces.
Multiple level ACDF can
devascularize the
vertebral body (or
bodies) between
discectomies.
90. CONSTRUCT
SELECTION
1) the graft and implant must correct the specific preoperative instability
(2) the long-term success of a cervical construct ultimately relies on the
quality of the osseous fusion.
cervical spine constructs are generally applied in the neutral mode
cervical constructs conform to one of five fundamental load-bearing types:
(1) distraction fixation
(2) tension-band fixation
(3) three-point bending
(4) fixed moment arm cantilever beam
(5) nonfixed moment arm cantilever beam fixation
95. Plating or
not….
• 1 level ADCF:
• The addition of an anterior plate to an ACDF is
recommended to reduce the pseudarthrosis rate
and graft problems (Level D Class III) and to
maintain lordosis (Level C Class II)
• but it does not improve clinical outcome alone
(Level B Class II)
• 2 level ADCF:
• Plating is recommended to improve arm pain.
• Plating does not improve other outcome parameters
96. Choice
of
graft
material Autologous bone (usually from iliac
crest)
non-autologous bone (cadaveric)
bone substitutes (e.g.
hydroxylapatite17) or synthetics (e.g.
PEEK or titanium cage) filled with
osteogenic material
99. Use of bone
morphogeni
c proteins
(BMP)
• not FDA approved, but has been used off
label.
• Complication rates as high as 23–27% have
been reported (including post-op swallowing
or respiratory difficulties as a result of
edema which is usually temporary
110. UTILITY
OF
DYNAMIC
CERVICAL
FIXATION
no difference in clinical outcomes
no differences in the fusion rates between dynamic and static plates
for single level
Improved fusion rates and clinical outcomes have been reported
with the use of dynamic plates for multilevel fusions.
Fewer implant complications and faster graft incorporation have
generally been reported when dynamic plates
Loss of cervical alignment (lordosis) has been reported with the use
of dynamic cervical plates.
With regard to adjacent level surgery (degeneration), there does not
appear to be any difference between dynamic and static plates
the use of a shorter plate with longer angulating screws has been
shown to significantly reduce adjacent level ossification
114. Subsidence
• has dual meanings and implications.
• It can refer to the loss of height that occurs normally with aging as
the axial skeleton shortens.
• it can also refer to the loss of height at an operative site after
surgery on the spine.
120. Adjacent segment disease (ASD)
• degeneration that develops at a motion segment adjacent to a previous
fusion.
• Findings include: disc degeneration, stenosis, facet hypertrophy, scoliosis,
listhesis and instability.
• After ACDF, ASD occurred at a rate of 2.9% per year over 10 years
observation
• 25% of patients will develop symptomatic adjacent level changes within 10
years of surgery.
• higher with single level fusion at C5–6 or C6–7 than it was with
multilevel fusion
• natural progression of the disease was felt to be a significant contributor
121. Cervical disc arthroplasty
• An alternative to fusion.
• Uses an artificial disc to preserve motion at the level of the discectomy.
• .
• Cervical Disc Herniation
• 70
123. Contraindications :
• isolated axial neck pain,
• ankylosing spondylitis
• Pregnancy
• rheumatoid arthritis
• autoimmune disease, diffuse idiopathic skeletal hyperostosis
• severe spondylosis with bridging osteophytes or OPLL,
• disc height loss > 50%
• spinal infection
• metal allergy to components of the prosthesis
• severe osteoporosis/osteopenia
• active malignancy, metabolic bone disease, trauma, segmental instability
3 or more levels requiring treatment
124. Posterior approach
• Options include:
• 1. laminectomy alone laminectomy/arthrodesis (i.e. laminectomy +lateral mass fusion): Class III
• (this procedure was found to be effective, the class shows the strength of the evidence
2. laminoplasty (Class III; this procedure was found to be effective, the class shows the strength of
the evidence): methods include unilateral (“open door”) and midline enlargement (“French door”)
• 3. multilevel foraminotomies: usually not adequate for central canal stenosis
125. Situations
where a
posterior
approach
would
generally be
the initial
approach
• 1. congenital cervical stenosis where removing
osteophytes will still not provide at least ≈ 12 mm of
AP canal diameter
• 2. disease over ≥ 3 levels (although up to 4 may
occasionally be dealt with anteriorly)
• 3. primary posterior pathology (e.g. in folding of
ligamentum flavum)
• 4. some cases of OPLL (anterior approach has higher
risk of dural tear)
126. Disadvantages of the posterior approach
• 1. laminectomy without fusion
• a) degeneration and osteophytes continue to progress following surgery
• b) risk of subsequent subluxation or progressive kyphotic angulation (“swan neck”
deformity)
• 2. more painful initially post-op and sometimes more prolonged rehabilitation
• 3. long-term complaints of a heaviness of the head possibly associated with atrophy of
the paraspinal
• Muscles
• 4. contraindicated with pre-existing swan neck deformity, and not recommended in the
presence of reversal of the normal cervical lordosis presence of ≥ 3.5 mm subluxation or
>20° rotation in the sagittal plane46 and caution must be exercised in hyperlordosis
139. Post laminectomy kyphosis
• The reported rate of post-op spinal deformity is 25–42%.
• Neurologic worsening has been reported in 2% in some series
• To avoid significant destabilization of the cervical spine:
• 1. during the dissection, do not remove soft tissue overlying the facet joints (to preserve their
blood supply)
• 2. take the laminectomy only as far lateral as the extent of the spinal canal, carefully
preserving the facet joints
• 3. avoid removing a total of one facet at any given level
144. Entry sites
• Figure 70-9. Photograph of a
cervical spine model
demonstrating bone entry sites. A,
Transuncal approach as originally
described by Jho. B, Upper
transcorporeal approach as
described by Jho. C, Lower
transcorporeal approach. D, Upper
transcorporeal approach as
described by Choi and colleagues
145. Outcome
• Once CSM is clinically apparent, complete remission almost never
occurs.
• The prognosis with surgery is worse with increasing severity of
involvement at the time of presentation and with longer duration of
symptoms (48% showed clinical improvement or cure if operated within 1
yr of onset, whereas only 16% responded after 1 yr7).
• The success of surgery is also lower in patients with other degenerative
diseases of the CNS
• Progression of myelopathy may be arrested by surgical decompression
