Transcript Document

Spinal injuries:
Recognition and Therapy
Ian Scott Feb 6 2002
Definition

(Stedmans 1998)
The Spine:
A short sharp process of bone; a
spinous process
 A thorn
 Columna Vertebralis

Really not much help
Ian Scott Feb 6 2002
The Spinal Column
C-Spine (44%)
Thoracic Spine (41%)
Lumbar Spine
(15%)
Sacral Spine
Ian Scott Feb 6 2002
Cervical Spine
The most vulnerable yet most
common site of injury.
Data from the UK (1993-95)
44% of all spine trauma
occurs at the cervical level
Ian Scott Feb 6 2002
Incidence of SCI



20-40 cases per million per year
US data 10 000 cases per year
Of these 10 000 cases

40% are “complete”
 No
sensory or motor function
below the lesion
• 4 000 cases per year of
tetra/paraplegia
Ian Scott Feb 6 2002
Incidence of SCI cont.

Disease of the young male

85% male
 Age

usually between 15-35 years
Mechanisms of injury (UK vs. Can)
MVA
 Sport
 Domestic/Work
 Assault

Ian Scott Feb 6 2002
36% / 36%
20% / 14%
37% / 44%
6.5% / 6%
Cost of Spinal Cord Injury

Lifetime direct medical costs range
between $325 000 - $1 350 000



Varies according to age at injury as
well as severity of injury
High Tetraplegics account for over
80% of expenditures
$7.7 Billion per year in USA
Ian Scott Feb 6 2002
Spinal Injuries

The devastating effects on the
patient, as well as the burdensome
effect on health care dollars has
created an urgency for a cure.

WHAT CAN BE DONE?
Ian Scott Feb 6 2002
Spinal Injuries

The patient with potential spine injury.
Injury prevention
 Pre-hospital care
 Emergency triage
 Surgical Management
 Medical Management
 Rehabilitation

Ian Scott Feb 6 2002
Spinal Injuries

The patient with potential spine injury.
Injury prevention
 Pre-hospital care
 Emergency triage
 Surgical Management
 Medical Management
 Rehabilitation

Ian Scott Feb 6 2002
SCI pre-hospital care

We are instructed to maintain
potential SCI patients “in a Neutral
position” for fear of worsening the
initial injury


“Pithing the Frog”
Cervical Hard collar is North
American Standard of Care.
Ian Scott Feb 6 2002
Identifying the SCI patient

Emergency medical personnel
are usually the first on the
scene.

Who should be placed in spinal
precautions?
Ian Scott Feb 6 2002
Who should get spinal precautions?


Stroh & Braude (Ann Emerg Med June 2001)
Retrospective chart review


Fresno County EMS Spine
protocol
861 patients discharged from
hospital with SCI from 1990-96

504 patients brought by EMS


495 were in Spinal precautions
What about the 9 patients that
weren’t?
Ian Scott Feb 6 2002
Fresno County EMS policy #530
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Spinal immobilization
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Implement spinal immobilization under following
circumstances:






Spinal pain or tenderness, include any neck pain with hx of
trauma
Significant Multi trauma
Severe facial/head trauma
Numbness/weakness after trauma
Loss of consciousness caused by trauma
If altered mental status and
• No hx available
• Found in setting of possible trauma
• Near drowning with hx or probability of diving
Ian Scott Feb 6 2002
Fresno Protocol

Of the 9 patients not immobilized
2 refused immobilization AMA
 2 could not be immobilized


The remaining 5 patients however:

2 patients had criteria BUT were not immobilized
 Protocol


violation
3 patients were missed by protocol
This leaves a 499/504 ratio 99% sensitivity
Ian Scott Feb 6 2002
Pre-hospital immobilization

An interesting point:

Do ANY patients
with suspected SCI
need immobilization?
(Hauswald Acad Emerg Med Mar 1998)
Ian Scott Feb 6 2002
Out of Hospital spinal immobilization: its effect
on neurologic injury


5 year retrospective chart review
Effect of emergent immobilization
on neurologic outcome, comparing
two different University hospitals

University of Malaya, Malaysia
 120

patients
University of New Mexico
 334
patients
Ian Scott Feb 6 2002
Who Cares?

Malaysia




New Mexico
Similar hospital
Similar Staff
NO SPINAL
PRECAUTIONS

Ian Scott Feb 6 2002
Universal
precautions
Who Cares?

Malaysia





New Mexico
Similar hospital
Similar Staff
NO SPINAL
PRECAUTIONS

Universal
precautions
Out of hospital
immobilization
has little effect on
outcome
Less neurologic
disability in
malaysian
patients at
discharge
Ian Scott Feb 6 2002
Of course we can’t!

A retrospective study has many significant pitfalls
but it suggests a few things

Spinal cord injury is primarily the result of the initial
impact.
 Secondary
damage may be caused by swelling,
ischemia etc, but NOT necessarily by unrestricted
movement post injury
 There may be unrecognized morbidities associated
with spinal immobilization.
Ian Scott Feb 6 2002
Morbidity associated with Spinal
immobilization

Several studies have questioned
the wisdom of routine spinal
immobilization
Pain and discomfort
 Respiratory compromise
 Increased intracranial pressure
 Actual worsening of symptoms

(numerous references)
Ian Scott Feb 6 2002
Identifying potential SCI: Clearing
the Spines

There is no easy solution.


We must recognize that MANY
people will be immobilized in the
hopes of preventing further injury
to those patients with true spinal
injury.
Efforts must be made to “clear” low
risk patients quickly and efficiently.
Ian Scott Feb 6 2002
Spinal injury

To identify the 10 000 people
each year with spinal injury,
emergency physicians will
screen approximately 800
000 patients with spinal
radiography.

Two recent papers address
this situation
Ian Scott Feb 6 2002
NEXUS: National emergency Xradiography Utilization Study



Hoffman et al NEJM 2000 343:94-99
Prospective observational study to validate decision rule
for low risk patients
Decision instrument as follows:

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Absence of tenderness in posterior midline
Absence of neurologic deficit
Normal level of alertness (GCS 15)
No evidence of intoxication
No distracting pain elswhere
Ian Scott Feb 6 2002
NEXUS

Patients who fulfilled all five criteria
were considered low risk for Cspine injury and therefore do not
require C-spine radiography

If patients had any of the 5 criteria,
they would have radiographic
imaging in the form of 3 views

AP, lateral and odontoid views
Ian Scott Feb 6 2002
NEXUS


34 069 patients enrolled
818 patients had significant c-spine
injury
810 were identified as potential
spinal injury patients by the
decision rule
 8 patients were identified as low
risk, but in fact had radiographic
injury

Ian Scott Feb 6 2002
NEXUS
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Sensitivity 99%
Negative predictive value 99.8%
Specificity 12.9%
Positive predictive value 2.7%
Radiographic imaging could have been avoided in
4309 patients (12.6%) of the 34 069 patients
Ian Scott Feb 6 2002
Ian Scott Feb 6 2002
NEXUS

Several concerns have been
raised regarding NEXUS

Screening C-spines with three
views may not be sensitive enough
to detect all spinal injuries in the
study population
 Many
centres advocate use of
bilateral oblique views also (5
views)
Ian Scott Feb 6 2002
NEXUS

Many emergency physicians also
feel the criteria are too vague and
open for interpetation
Distracting injuries
 Presence of intoxication


Enter the Canadian C-spine rules..
Ian Scott Feb 6 2002
Canadian C-spine rules (JAMA Oct 17 2001)

Brought to fruition by same group who
developed the Ottawa Ankle rules

Prospective cohort study, patients
evaluated for 20 standardized clinical
findings PRIOR to radiography
Hx of blunt trauma to head/neck,
hemodynamically stable, with GCS 15

Ian Scott Feb 6 2002
Canadian C-spine rules
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8924 patients enrolled
151 patients had important c-spine
injury (1.7%)

Derived Decision rule as follows:
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Ian Scott Feb 6 2002
Canadian Rules…
Ian Scott Feb 6 2002
Canada Rules
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1) Any High risk factor that mandates radiography?

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Age>65, dangerous mechanism, paresthesias
2) Any low risk factors that allow safe assessment of
range of motion
Simple rear end MVC, sitting position in ER, Ambulatory
at any time, delayed onset of neck pain, absence of
midline tenderness
 3) Able to rotate neck?

 45
degrees left and right
Ian Scott Feb 6 2002
Canadian C-spine rules


100% sensitivity
42.5% specificity

Potential radiography order rate
58.2%
Unfortunately, these rules do not
apply to the usual ICU patients
Ian Scott Feb 6 2002
Spinal Radiography in critically ill


No clear consensus.
Full agreement that patients with
trauma and decreased LOC must
be assumed to have spinal fracture
until cleared clinically and/or
radiographically
Ian Scott Feb 6 2002
C-spine radiography

Bare Minimum:
Cross table lateral
 Anteroposterior view
 Open mouth odontiod


If adequate views NOT attainable,
patient requires CT scan
reconstructions of disputed areas
Ian Scott Feb 6 2002
Lateral c-spine view
Lateral views
have a
sensitivity of
approx 80% to
identify c-spine
fractures
Ian Scott Feb 6 2002

Ian Scott Feb 6 2002
Disruption of
all spinal lines
with obvious
anterior
dislocation
Vertebral Burst
fractures
Ian Scott Feb 6 2002
SCIWORET worth a mention

SCIWORET is Spinal cord injury without
radiographic evidence of trauma
First described in pediatric population (SCIWORA)
 In adults, tends to affect the elderly

 Much
more prevalent in cervical spine as opposed to
the thoracolumbar area.
• Related to the degenerative changes in the c-spine
Ian Scott Feb 6 2002
Pathophysiology of Spinal Cord injury

Primary mechanisms


Initial crush, shear impingement of
cord with the inciting trauma.
Secondary mechanisms
Vascular insults/insufficiency
 Edema
 Cell toxicity
 Apoptosis

Ian Scott Feb 6 2002
Secondary Injury
Electrolytes
Cell toxicity
Vascular
CELL DEATH
Decreased
energy
(ATP)
Edema
Apoptosis
Ian Scott Feb 6 2002
Secondary Mechanisms
Ian Scott Feb 6 2002
Secondary Mechanisms

Electrolytes


Cell toxicity

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Glutamate release, arachidonic acid metabolites, free
radical generation
Apoptosis


Calcium release
Programmed cell death
Vascular

Disautoregulation, hypotension, neurogenic shock
Ian Scott Feb 6 2002
Secondary mechanisms

Numerous mediators of spinal cord damage have
been identified experimentally.

The hope is that through simple pharmacologic
interventions, the secondary damage can be limited,
or even potentially reversed.

Unfortunately very little clinical progress has been
made to date.
Ian Scott Feb 6 2002
Steroids

Several studies have reported success with high
dose steroid infusions, limiting progression of spinal
cord damage in trauma.

NASCIS II and III (NEJM 1990, JAMA 1997)
 Two
highly publicized studies demonstrating small but
clinically significant improvement with neurologic
recovery following administration of high dose methylprednisolone
• NASCIS II placebo controlled
• NASCIS III dose varied. Not placebo controlled
Ian Scott Feb 6 2002
NASCIS II

Steroid bolus 30mg/kg over 15min in 1st hour,
then 5.4mg/kg/hr for 23 hours


An average 70Kg patient would receive 23
GRAMS of steroid over 24 hours
NASCIS II was in fact a negative study.

Only on post hoc sub group analysis did steroid
yield a “benefit”
 Only
patients who received steroid in the first 8
hours post injury demonstrated a benefit

What degree of benefit however?
Ian Scott Feb 6 2002
The Controversy


Unfortunately, the degree of “statistically significant
benefit” has no clinical relevance
Motor score improvements were 17 .2 and 12.0 for
steroid and placebo groups respectively (out of a
total possible score of 70), which gives a difference
of 5.2.

A difference of 5.2 simply put could be gained if a
patient regained the ability to shrug his shoulders.
Ian Scott Feb 6 2002
Important Papers

NASCIS II


NASCIS III
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
JAMA 1997 277:1597-1604
Revisiting NASCIS II & III


NEJM 1990 322:1405-11
J. Trauma 1998 45:6 1088-93
Methylprednisolone for acute spinal injury….

J. Neurosurg (Spine 1) 2000:93:1-7
Ian Scott Feb 6 2002
Future Directions

Glutamate receptor inhibition

Peripheral nerve transplants

Glial cell regeneration

Axon growth, guidance and
synaptogenesis
Ian Scott Feb 6 2002
Ian Scott Feb 6 2002