ian scott feb 6 2002 spinal injuries: recognition and therapy

Ian Scott Feb 6 2002

Spinal injuries: Recognition and Therapy


Definition (Stedmans 1998)

The Spine: A short sharp process of bone; a

spinous process A thorn Columna Vertebralis

Really not much help


The Spinal ColumnC-Spine (44%)

Thoracic Spine (41%)

Lumbar Spine

Sacral Spine

(15%)


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


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


Incidence of SCI cont.

Disease of the young male 85% male

Age usually between 15-35 years

Mechanisms of injury (UK vs. Can) MVA 36% / 36% Sport 20% / 14% Domestic/Work 37% / 44% Assault 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


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?


Spinal Injuries

The patient with potential spine injury. Injury prevention Pre-hospital care Emergency triage Surgical Management Medical Management Rehabilitation


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.


Identifying the SCI patient Emergency medical personnel

are usually the first on the scene.

Who should be placed in spinal precautions?


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?


Fresno County EMS policy #530 Spinal immobilization

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


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


Pre-hospital immobilization

An interesting point: Do ANY patients

with suspected SCI need immobilization?

(Hauswald Acad Emerg Med Mar 1998)


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


Who Cares?

Malaysia Similar hospital Similar Staff NO SPINAL

PRECAUTIONS

New Mexico Universal

precautions


Who Cares?

Malaysia Similar hospital Similar Staff NO SPINAL

PRECAUTIONS

Less neurologic disability in malaysian patients at discharge

New Mexico Universal

precautions

Out of hospital immobilization has little effect on outcome


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.


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)


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.


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


NEXUS: National emergency X-radiography 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:

Absence of tenderness in posterior midline Absence of neurologic deficit Normal level of alertness (GCS 15) No evidence of intoxication No distracting pain elswhere


NEXUS

Patients who fulfilled all five criteria were considered low risk for C-spine 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


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


NEXUS

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


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)


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..


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


Canadian C-spine rules

8924 patients enrolled 151 patients had important c-spine

injury (1.7%)

Derived Decision rule as follows:


Canadian Rules…


Canada Rules 1) Any High risk factor that mandates radiography?

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


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


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


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


Lateral c-spine view

Lateral views have a sensitivity of approx 80% to identify c-spine fractures


Disruption of all spinal lines with obvious anterior dislocation


Vertebral Burst fractures


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


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


Secondary Injury

Electrolytes

Cell toxicity

Decreased energy(ATP)

Edema

Vascular

Apoptosis

CELL DEATH


Secondary Mechanisms


Secondary Mechanisms Electrolytes

Calcium release Cell toxicity

Glutamate release, arachidonic acid metabolites, free radical generation

Apoptosis Programmed cell death

Vascular Disautoregulation, hypotension, neurogenic shock


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.


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 methyl-prednisolone

• NASCIS II placebo controlled• NASCIS III dose varied. Not placebo controlled


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?


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.


Important Papers

NASCIS II NEJM 1990 322:1405-11

NASCIS III JAMA 1997 277:1597-1604

Revisiting NASCIS II & III J. Trauma 1998 45:6 1088-93

Methylprednisolone for acute spinal injury…. J. Neurosurg (Spine 1) 2000:93:1-7


Future Directions

Glutamate receptor inhibition

Peripheral nerve transplants

Glial cell regeneration

Axon growth, guidance and synaptogenesis

ian scott feb 6 2002 spinal injuries: recognition and therapy

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