An Overview of Cervical
Facet Injury Due to RearImpact Automobile
Collisions
DR. BARRY L. MARKS
PRACTICE OF CHIROPRACTIC
--EMPHASIS ON
AUTOMOBILE & INDUSTRIAL INJURIES
ORANGE, CALIFORNIA
(714) 938-0575
“S” Shape Spine the Source of Damage to
Cervical Facet Joints in “Whiplash”
Injuries
In 1997 MM Panjabi and JN Grauer of the Dept. of
Orthopaedics and Rehabilitation at Yale University School of
Medicine conducted “whiplash” studies on human cadavers.
The cadavers were subjected to forces simulating a rearimpact automobile collision while high speed motion x-rays
caught the effects on film. Researchers made a startling new
discovery. It was always thought that hyperextension
occurred in the neck, which resulted in “whiplash” injuries.
This study in 1997 found that the lower vertebrae of the neck
(C5-6) actually changed their axis of motion and spun
backwards causing their posterior joints (facets) to collide,
while the top of the neck was bent forward momentarily. At a
given point into the collision, the neck actually formed an “Sshape”.[1]
This study found much attention and in 1998 Panjabi MM,
Cholewicki J, Nibu K, Grauer JN, Babat LB, Dvorak J and
Bar HF repeated the study at the Yale University School of
Medicine only this time using live human subjects. The
principles of the 1997 study were able to replicate the results
of the previous test on live human volunteers. The same “Sshaped” configuration was noted and the lower cervical facet
extension was noted. The test was performed at various
collision speeds to find the human tolerance for such an
injury. The results were shocking. The “S-shape”
configuration was observed in speeds as low as 2.5 mph.[2]
In 1999 Koji Kaneoka, Koshiro Ono, Satoshi Inami and
Koichiro Hayashi of the Department of Orthopedic Surgery at
the University of Tsukuba, Japan repeated the second
Panjabi study, again on live human volunteers. The results
were the same. This third study confirmed for the world of
spinal researchers the mechanism by which human spines
are damaged in rear-impact automobile collisions.[3]
Analysis & Summary of Panjabi & Kaneoka Studies
Human subjects were placed in vehicles that were subjected
to rear-impact collisions at various speeds. The spine was
recorded using high-speed motion X-rays, called
cineradiography.
At 50 milliseconds into the impact, the lower cervical
vertebrae at C5-6-7, rotate into extension causing stretching
and tearing of ligaments in front of the spine and
compressing of facet joints resulting in facet joint surface
damage.
At maximum extension of C5-6-7, the upper vertebrae flex
forward making an S-shape curve, stretching and tearing
soft tissues of the back of the neck.
The damage occurs in fractions of a second, before the
patient is aware of the collision.
The tests proved:
1. The spine deforms into an S-shape
2. Damage of the facets occurs in rear-impact collisions
due to the rotation of the lower vertebrae into extension
without “hyperextension”
3. The damage occurs prior to consciousness and before
reflexes can protect the neck
4. Damage occurs at very low speeds, as low as 2.5 mph
“The study of Kaneoka et al now fills a critical gap
in the story of cervical facet pain. It provides the
missing biomechanical link. Theirs is the most
significant advance in biomechanics of whiplash
since the pioneering studies of Severy et al in 1955”
“As a result of this study, we no longer rely on
inference or speculation; we have a direct
demonstration of the mechanism of injury in
whiplash.”[4]
Nikolai Bogduk, MD, PhD, DSc, FAFRM
Dept. of Anatomy and Musculoskeletal Medicine
University of Newcastle
Newcastle Bone and Joint Institute
Royal Newcastle Hospital
Newcastle, New South Wales, Australia
The Facet Joints are the Primary Area of
Damage and Pain in the Neck from
Whiplash Injuries
“Cervical (facet) joint pain is common among
patients with chronic neck pain after whiplash…
and has proven to be of major clinical
importance”[5]
Nikolai Bogduk, MD, PhD, DSc, FAFRM
Due to the S-shape deformation of the cervical spine on
impact, the facet joints are severely compressed causing
damage to the articular cartilage surface. This results in
predictable pain patterns that are readily identified on
physical examination.
The pattern of pain from an injured facet joint has been
referred to as “Sclerotomal” pain. Unlike dermatomal pain,
which describes pain from a nerve root to it’s corresponding
body part like in a herniated cervical disc radiating pain into
the arm or hand, Sclerotomal pain corresponds with
embryonic origin of tissues so that a source of pain may be
widely separated from it’s radiation pattern and has no
corresponding neurologic connection. In the cervical spine
facet joints, damage sends pain to the lateral aspect of the
neck and down into the scapula region. It can be aggravated
for diagnostic purposes by bending the neck laterally and
into extension, compressing the facets and reproducing the
pain pattern.
Facet joint injuries CANNOT be found on MRI or
electrodiagnostic tests like EMG and NCV, but objective
proof can be found if the practitioner knows how to find it.
Sclerotomal pain pattern of the cervical
facet joints as described by Dwyer, Fracs,
Aprill and Bogduk in December 1989
Annals of Surgery
Delay in Onset of Symptoms Is Common
and Can Affect Prognosis
Delayed onset of symptoms is common according to the
scientific literature.[6],[7],[8] More severe injuries, such as disc
herniation and severe ligament tearing usually become
symptomatic very quickly. Other less destructive injuries may
take over 48 hours to materialize. A Spanish study found
that 31.5% of rear impact crash victims reported to an ER
between one and three days after the crash. [9] Later onset of
symptoms has actually been linked to longer treatment
duration and poorer prognosis. Richter et al found that
symptoms lasted nearly twice as long as average for those
with a delay in onset of more than 24 hours.[10]
Another aspect related to delayed symptoms is the “second
wave” phenomenon. This has been described by several
authors. Wherein a whiplash victim initially complains of
neck pain and then later, weeks, and even months later, a
“second wave” or second phase of symptoms emerge. Bring
and Westman (450) reported a second wave of symptoms
occurring many months later. Gargan and Bannister (456)
reported a late onset of neck pain, extremity pain or
paresthesia, interscapular pain, tinnitus, headache,
dizziness, and visual disturbance after 1 week supporting the
“second wave” phenomenon.
This accounts for those patients who are initially treated,
found to be stationary and released only to return later with a
return of old symptoms and often new complaints such as
carpal tunnel syndrome, tedninopathies, post concussion
syndrome, disc derangements, and others.
Documenting Facet Joint Injuries
As we have seen cervical facet joints are the leading factor
in neck pain form automobile collisions. We have also
learned that they occur even in very low speed collisions and
that they cannot be visualized on MRI or with EMG or NCV
tests.
The documentation of facet joint injury and damage is done
in two manners:
1. Clinical examination
Subjective pain patterns for facet joints are predictable and
reproducible. Careful documentation of the patient’s
complaints leads to a suspicion of facet joint damage after a
MVC.
Objective examination procedures that provoke the facet
joints can be employed and is a reproducible means of
locating facet joint damage. Particularly, simultaneous lateral
flexion and extension of the suspected joint will yield the
characteristic pain pattern described earlier. Other
compressive type tests, such as foramina compression and
maximum cervical compression may also elicit the tell-tale
findings.
2. Imaging
Digital Motion Fluoroscopy is the imaging procedure used by
Panjabi and Kaneoka in their landmark studies on whiplash
injuries. It is a high speed x-ray that is able to display the
skeleton as it actually moves. In essence, it is a live x-ray
video. The images can then be analyzed by a radiologist for
defects in motion. The most common defects found are of
the alar and accessory ligaments of the C1-C2 vertebrae,
which manifests as excessive lateral movement of the C1
segment and the facet capsular ligaments of C2 through C7,
which appears as excessive gapping of the involved facet
joint(s).
Chiropractic Treatment Best for
Whiplash Injuries
Facet joint injuries require appropriate treatment to minimize
or prevent later complications such as arthritis.
A 1996 study by renowned researchers Gargan and
Bannister, indicated:
"…benefits can occur in over 90% of patients
undergoing chiropractic treatment for chronic
'whiplash' injury."
"No conventional (medical) treatment has proven to
be effective in these established chronic cases."
[11]
Therefore, chiropractic care is the patient's best chance of
improving when suffering from whiplash injuries, even late or
chronic whiplash.
Chiropractic treatment benefits the patient with damaged
facet joints by restoring normal motion and mechanics to the
cervical facet joints through manipulation and rehabilitative
therapies and exercises.
Croft Guidelines for Whiplash
Severity & Treatment
In 1993, Arthur Croft, D.C., M.S., M.P.H., F.A.C.O.,
F.A.C.F.E., published a set of management guidelines in the
ACA Journal. These guidelines have also been published in
Whiplash Injuries: the Cervical Acceleration/Deceleration
Syndrome, second edition, in 1995 and in a recent Canadian
practitioner's guide to whiplash injuries, sanctioned by the
Canadian Chiropractic Association.
The Croft Guidelines have been a part of our literature now
for eight years. No competing guidelines relative to CAD
treatment have been published during that time, with the
exception of the Quebec Task Force Guidelines on WAD,
but these are only applicable for patients who remain on
disability. Several American state chiropractic organizations
and associations, as well as in at least one Canadian
province, have now adopted the Croft Guidelines.
Grades of Severity of Injury
Grade 1 - Minimal; No limitation of motion; No ligamentous
injury; No neurological findings
Grade 2 -Slight; Limitation of motion; No ligamentous injury;
No neurological findings
Grade 3 - Moderate; Limitation of motion; Ligamentous
instability; Neurological findings may be present
Grade 4 - Moderate to Severe; Limitation of Motion; Some
ligamentous injury; Neurological findings present; Fracture or
disc derangement
Grade 5 - Severe; Requires surgical management and/or
stabilization
Guidelines for Frequency and Duration of Care in
Cervical Acceleration/Deceleration Trauma
Daily
TN
Grade I
<21
Grade II
<33
Grade III
Grade IV
Grade V
3x/wk
2x/wk
1x/wk
1 wk
1-2wk
2-3 wk
<4 wk
1 wk
<4 wk
<4 wk
<4 wk
1x/mo
--1
TD
<11 wk
<4 mo <29wk
1-2 wk <10 wk
<10 wk
<10 wk <6 mo<56 wk
<76
2-3 wk <16 wk
<12 wk
<20 wk
--2 --2
--2
Surgical stabilization necessary - chiropractic care is post-surgical
TD = treatment duration; TN = treatment number
1 = Possible follow-up at 1 month
2 = May require permanent monthly or p.r.n. treatment
The most common whiplash injuries are Grade II and Grade
III. Occasionally, Grade IV’s will present, but they are fairly
rare. Grade V’s are seen only after extensive and invasive
treatment has been performed through an orthopedic or
neuro surgeon.
Grade I’s are fairly rare also as the pain level may not be
enough to prompt the patient to seek evaluation and/or they
have been examined by another medical provider who did
not recognize the need for care in these patients.
Duration of Care for Whiplash Injuries
Medical researchers point to the fact that a minimum of 25%
of all motor vehicle collisions result in chronic pain that may
take up to 2 years before becoming stabilized.[12] Other
authors have stated the figure to be over 40%.[13]
Schofferman and Wasserman in SPINE Vol 19, Number 9,
1994 found the “average” collision induced injury to take 7
months and 1 week before becoming stable. They
mentioned “tough” cases take approximately 108 weeks or
about 2 years. Lastly, Ryan and Taylor, et al found 66% of
patients had not recovered 6 months post-accident.[14]
These figures roughly approximate the Croft Guidelines and
can be simplified to generalize that:
Grade I injuries can take up to 3 months to stabilize
Grade II injuries can take up to 7 months to stabilize
Grade III injuries can take up to 14 months to stabilize
Grade IV injuries can take up to 2 years to stabilize
Poor Prognosis for Chronic Whiplash
“25% of whiplash injuries will progress to chronic
symptoms. These patients injured their discs or facet
joints. These patients will not resolve spontaneously
and they do become chronic. They may improve
over a period of 2 years, but are unlikely to improve
after 2 years.”
“10% of patients with whiplash injuries develop
constant severe indefinite neck pain.”[15]
Other studies have found the chronic cases number to be
even higher. A consensus of recent research found the
chronicity rate to be 38%[16]
Osteoarthritis 6 Times More Likely
After Whiplash
Damage to the facet joint surface leads to breakdown of the
tissue and permanent arthritic changes.
Studies by Hohl and Miyamoto et al. report increase
incidence of osteoarthritis following whiplash that is
permanent often leaving the victim with years or perhaps a
lifetime of residual pain and disability.[17],18,19
Summary
The latest scientific and medical research indicates that it is
the "S" configuration of the spine tat results in damage to the
neck in rear-impact motor vehicle collisions. These injuries
can occur at very low speeds. The facet joints are the most
commonly damaged structures within the neck from these
collisions. There may be a delay of symptoms from hours to
days and in some cases even longer. Clinical and
radiological tests can readily detect these injuries.
Chiropractic has been shown to be the preferable treatment
of these injuries and is particularly helpful in chronic or late
whiplash. Late whiplash occurs in up to 38% of cases and
increases the chance to develop early osteoarthritis.
References
[1]
Panjabi MM, Grauer JN (1997): "Whiplash produces a S-shape curvature of the neck with
hyperextension at lower levels. " Spine 22 (21): 2489-94.
[2]
Panjabi MM, Cholewicki J, Nibu K, Grauer JN, Babat LB, Dvorak J, Bar HF (1998-12-01):
"[Biomechanics of whiplash injury]." Orthopade 1998 Dec; 27(12): 813-9.
[3]
Koji Kaneoka, Koshiro Ono, Satoshi Inami and Koichiro Hayashi (99-04-15). "Motion analysis
of cervical vertebrae during whiplash loading." Spine 24(8): 763-770
[4]
[5]
Spine 1996; 21: 1737-1745
Pain, 54 (1993) 213-217
Gotten N: Survey of one hundred cases of whiplash injury after settlement of litigation. JAMA
162(9):865-867, 1956.
[7] Deans GT, Magalliard JN, Kerr M, Rutherford WH: Neck sprain--a major cause of disability
following car accidents. Injury 18:10-12, 1987.
[8] Braaf MM, Rosner S: Symptomatology and treatment of injuries of the neck. NY State J Med
55:237-242, 1955.
[9] Loro MBG-M, Yuste PG, Perez CG, Garcia MTM, Lorenzo AH. Epidemiology of traffic crashes
in a general hospital. 43rd Annual Proceedings of the Association for the Advancement of
Automotive Medicine. September 20-21, 1999, Barcelona, Spain, 437-438.
[10] Richter M, Otte D, Pohlemann T, Krettek C, Blauth M. Whiplash-type neck distortion in
restrained car drivers: frequency, causes and long-term results. European Spine Journal 9:109117, 2000.
[11]
Injury 27(9): pp. 643-645
[12]
Barnsley, Lord, Bogduk, Whiplash Injury Clinical Review, Pain 58, 1994, pp. 283-307
[13]
Woodward, Cook, Gargan and Bannister (1996) "Chiropractic treatment of chronic 'whiplash'."
Injury 27(9): pp. 643-645.
[14]
Ryan, G., V. Taylor, et al. (1994). “Neck strain in car occupants: injury status after 6 months
and crash-related factors.” Injury: International Journal of the Care of the Injured 25 (8): 533-537.
[6]
[15]
Whiplash Injury Clinical Review Lord, Barnsley and Bogduk Pain 58, 1994, 283-307
9th Annual SRISD Scientific Conference, Coronado, CA November 2004
[17]
Foreman, D. and Croft, A., Whiplash: The Cervical Acceleration/Deceleration Syndrome,
1989, Williams & Wilkins
18
Hohl M: Soft tissue injuries of the neck. Clin Orthop Rel Res 109:42-49, 1975
19
Miyamoto S: Spine 16(10):5495-5500, 1991
[16]