Download Fractures of the Articular Processes of the Cervical Spine

239
Fractures of the Articular
Processes of the Cervical
Spine
John H. Woodring'
Steven J. Goldstein'
Fractures of the articular processes occurred in 16 (20.8% ) of 77 patients with
cervical spine fractures as demonstrated by multidirectional tomography. Plain films
demonstrated the fractures in only two patients. Acute cervical radiculopathy occurred
in five of the patients with articular process fractures (superior process, two cases;
inferior process, three cases). Persistent neck pain occurred in one other patient
without radiculopathy. Three patients suffered spinal cord damage at the time of injury,
which was not the result of the articular process fracture itself. In the other seven
cases, no definite sequelae occurred. However, disruption of the facet joint may
predispose to early degenerative joint disease and chronic pain; unilateral or bilateral
facet dislocation was present in five patients. In patients with cervical trauma who
develop cervical radiculopathy , tomography should be performed to evaluate the
articular processes.
Fractures of the articular processes of the cervical spine have received little
attention in the literature. In one recent review of cervical spine traum a, they
were dismissed as occurring in fewer than 3 % of patients with cervical spine
fractures [1]. In our experience , the incidence of these fractures is much greater
and they may be associated with significant radiculopathy. We review the c lini cal
and radiographic manifestations of articular process fractures and emphasize the
value of tomography in the diagnosis of this entity.
Materials and Methods
During a 3 year period, 120 consecutive patients underwent multidirec ti onal tomography
for evaluation of cervical spin e trauma. Th ese patients either had fractures evident on
preliminary plain film s or were c linicall y suspected of having a fracture despite negati ve
plain film s.
The pl ain film s and tomograms were retrospectively and independentl y interpreted by
two observers . Agreement between th e two observers was excellent. The c lini ca l record of
each patient with an articular process fracture was also reviewed with specia l attention to
initial c linical presentation , treatment , and seq uela of the injury.
Results
This article appears in the May / June 1982
issue of AJNR and the AU9ust 1982 issue of
AJR.
' Departm ent of Di ag nostic Radiology, University of Kentucky Medica l Center, 800 Rose St.,
Lexington, KY 40536. Address reprint requests to
J. H. Woodring .
AJNR 3:239-242, May / June 1982
0195-6108 / 82 / 0303-0239 $00.00
© American Roentgen Ray Society
Of th e 120 patients who underwent to mog raphy , 43 had no fractu re. In 77 patients, one
or more frac tures were seen on tomography . Of th ose 77 patients with ce rvical spin e
fractures, 16 had arti cu lar process fra ctures and 6 1 had frac tures of oth er parts of the
vertebral bodies. Th e arti c ular process fractures we re best demonstrated by mu ltid irectional
tomography . Th e preliminary pl ain film s we re diag nosti c of an arti c ular proce ss frac ture in
only two pati ents.
Five of th e 16 pati ents with an arti c ular process fracture had an acute cerv ica l rad ic ulopath y at th e level of the fractu re (fig . 1). One pati ent had rad ic ul ar pain onl y, two patient s
had upper extremity weakness wi th out pain. Th e radicu lopathi es in th ese patients in vo lved
neural distributions co rresponding to the level of arti c ular process frac ture. Th e rad icu lo-
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WOODRING AND GOLDSTEIN
3
2
Fi g. 1.- Lateral tomog ram. Fract ure through left superi or arti c ul ar process o f C6 (arrow) with an teri or displacement of frag men t, w hi ch im pinged on
prox imal C7 nerve root produ cing rad icular pain and mu sc ul ar weakness.
s = superi or arti c ular process.
Fig . 2.-Frac ture through base of ri ght superior arti cular process (arrow)
o f C4 separating arti cular process from lateral mass. Transient Brown-
pathy was associated with fracture of a superi or artic ular process
in two cases and of an inferior process in three cases. In two of th e
three pati ents with radic ular pain, th e pain resolved at 6 weeks and
14 month s after injury, respec tively. Th e third patient was lost to
follow-up 6 month s after injury still co mpl aining of radicular pain. In
th e fo ur pati ents with upper extrem ity weakness, the symptoms
persisted until th e patients were lost to follow-up (average leng th of
follow-up was 9 months; range 6-18 months). Of those 61 patients
in o ur se ri es w ith fractures of parts of th e vertebral bodies other
th an the arti c ular processes, on ly four had a rad icu lopathy accompanying th eir injury. Th erefore, nerve root compress ion would appear to be about five tim es more likely in cases of arti c ular process
fracture co mpared with oth er frac ture s of the ce rvical spine.
In one ot her case without radiculopathy, the patient comp lained
of severe nec k pain at th e fracture site for 8 months before being
lost to follow-up . The se six of 16 patients with articu lar process
frac tures in our se ri es had c linica ll y sign ifica nt sequelae of their
frac ture. In add ition, two patients with bilateral face t di slocation
were rendered qu ad ripl eg ic at the tim e of injury and one patient
with hyperextension injury to th e cervical co rd developed transient
Brown-Seq uard syndrome. Th e neurologic deficits in th ese three
pati ents did not seem di rectly related to th eir articu lar process
frac ture; no specific seq uelae of th e articular process fracture itself
occurred . In th e ot her seven pati ents, th e articul ar process fracture
was asymptom ati c. In 10 patients the cerv ical spine was considered
to be stabl e; six patients required su rgical fu sion because of in stability.
In th e 16 patients with artic ular process fractures, a total of 18
frac tures was identified . Nine of th e fractures were limited to either
th e superi or or inferior arti c ular p rocess (fig s. 2 and 3). Th e oth er
nine fractures ex tensively involved th e lateral mass. In five patients ,
th e frac tures were associated wi th unil ateral or bil ateral facet di slocation . Th e level of fracture was as follows: C2 in two cases; C3 ,
C4, and C5 in one case eac h; C6 in 10 cases ; and C7 in three
cases. In two pati ent s, frac tures occurred at two adjacent levels
(C5 and C6 in one; C6 and C7 in th e other) .
AJNR:3, May / Jun e 1982
Sequard syndrom e deve loped secondary to hyperextension injury.
Fig . 3. -Unil ateral facet dislocation of C6 on C7 . Post reduction tomograms in lateral projection . Chip fracture (arrow) of left inferi or arti c ular
process of C6 with posteri or displacement of fracture fragment. i = inferior
arti c ul ar process.
Discussion
Fractures of the articular processes of the cervical spine
have been reported as occurring in 3 % -11 % of patients
with cervical fractures [1, 2] on the basis of a series of
patients evaluated by conventional plain films . In our series,
using multidirectional tomography , we found articular process fractures in 16 (20 .8%) of 77 patients with cervical
fractures . The plain films were diagnostic of articular process fractures in only two patients; therefore, it would seem
likely that the high percentage of patients with articular
process fractures in our series was due to the improved
accuracy afforded by tomography [3 , 4]. If plain films alone
had been relied upon, 87.5 % of these fractures would not
have been detected.
Most articular process fractures occurred in the lower
cervical spine. Thirteen of 16 fractures occurred at C6 and
C7. The other fractures were evenly distributed between C2
and C5. These figures are in accordance with those previously reported [2,5]. No fractures of the articular processes
of C 1 [6] were identified in our series. The fractures that
occurred between C3 and C7 were best demonstrated by
tomography in the lateral projection (figs. 1-4); however,
those fractures at the C2 level were best demonstrated in
the anteroposterior projection (fig. 5). In two of our patients,
articul ar process fractures occurred at two levels (C5 and
C6 in one and C6 and C7 in the other) . To our knowledge,
the occurrence of articular process fractures at two adjacent
levels has not been previously reported .
Fractures of the arti c ular processes may be isolated to
the articu lar process itself or extend to involve the lateral
mass of the vertebra as well [7]. In our series , half of the
fractures were limited to either the superior or inferior artic-
AJNR :3 . May / June 1982
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ARTICULAR PROCESSES FRACTURES
5
241
6
Fig . 4 .-Bilateral fac et di slocati on of C6 on C7 with assoc iated quadriplegia. Postredu ction tomograms in lateral projection . Fracture through base of
lell inferi or arti c ul ar process of C6 (arrow) . Fragment se parated from laleral
mass. posteri orl y displaced . and angul ated . Abnorm al w idening of facet joint
(arrowheads ).
Fig. 5. -Anteroposteri or tomogram of C2. Basilar fraclure o f od ontoid
process extends into rig hl superi or arli c ul ar process (arrow) .
Fig. 6. - Lateral tomog ram of pali ent w ith nec k pain aft er in ju ry 10 cervica l
spin e. Loss of height. sclerosis. and hype rtr ophic spurrin g (arrowh eads )
invo lving arti cular processes al C5- C6 level. s = superi or articular process;
i = inferi or arti cul ar process.
ular process; in the other half, the fracture also involved the
lateral mass.
Acute cervical radiculopathy has been reported as a
complication of articu lar process fracture in 6 % -39 % of
patients [2, 8]. In our series , five patients (31 .3 % ) developed
acute cervical radiculopathy associated with fractures of the
articular processes (fig. 1). Although radiculopathy has been
reported as occurring more often in fractures of the superior
articular process [2, 5 , 7], radiculopathy may occur from
fractures of either the superior or inferior articular processes
[2]. This is explai ned by the close anatomic relation of the
superior and inferior articular processes and the nerve root
exiting the intervertebral foramen. The superior and inferior
articular processes form the lateral margin of the intervertebral foramen. A fracture through the superior process with
anterior displacement of the fragment can result in compression of the nerve root as it lies against the superior process
[2 , 5, 7]. In cases of inferior process fracture with radiculopathy, there is usually no evidence of anterior displacement
of the fracture fragm ent si nce the superior process of the
vertebra below prevents anterior displacement of the inferior
process fragment [2]. Transient sublu xation at the time of
injury or assoc iated hematoma may compress the nerve
root as it courses near the inferior process in these cases .
This occurs in some cases of superior process fracture as
well. Although Nieminen [2] reported a lower occurrence of
radiculopathy in cases of inferior articular process fracture,
it was more common in our series. However, there does
appear to be a greater propensity for the radiculopathy to
resolve in cases of inferior articu lar process fracture compared with radiculopathy associated with superior process
fractures [2].
It would seem prudent that all patients with cervical spine
trauma who develop an acute cervical radiculopathy undergo multidirectional tomography to evaluate the arti c ul ar
processes at the affected level [5]. While many of th ese
patients may be treated nonsurgically [2] , surgical removal
of bony fragments from the intervertebral foramen may aid
in the recovery of neurologic deficits [2 , 5]. Most of th ese
patients are believed to have stable injuries ; however, associated instability has led to surgical fusion in som e [ 2]. In
our series , six patients (37.5 % ) required surgi ca l fu sion
because of associated instability.
Fracture of the cervical articu lar processes has been
shown to be a cause of persistent posttraumatic nec k pain
due to hypertrophic changes in the apophyseal joints and
chronic neck pain [7 , 9]. Although we were unabl e to obtain
long-term follow-up to determin e th e inc idence of pos ttraumatic degenerative disease in our patients , we recently
evaluated one patient with prior trauma who developed
severe degenerative disease of the involved joints (fi g. 6) .
Articular process fractures are gen erally acce pted as
being produced by forced hyperextension [2 , 10] of th e
cervical spine . The association of articul ar process fractures
with bilateral and unilateral facet dislocation in injuri es produced by forced fle xion and forced fle xion-rotation , res pectively [11], has rec eived little attention . In a se ri es of 3 00
patients with acute cervi c al injuri es, Bohlman [8] desc rib ed
four patients with arti c ul ar process fractures associated with
unilateral or bil ateral facet di slocati on. In our se ri es of 16
patients, five were assoc iated with unil ateral o r bil ateral
facet dislocation (fig . 3) sugg esting th at th e coinc id ence
may be frequent.
Three patients in our seri es had ce rvi cal cord injury. Two
had bilateral facet di slocation assoc iated with qu adripl eg ia;
one patient had a hyperextensi o n injury with transient
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WOODRING AND GOLDSTEIN
Brown-Sequard syndrome. The spinal cord injuries in these
patients were not believed to be the d irect result of the
articular process fractures.
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1978;1 3 0: 659-663
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5 . Renaudin J, Snyder M . Chip fracture through the superior
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AJNR:3 , May/ June 1982
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