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198
13 Miscellaneous C2 Fractures
recommended surgical intervention in cases with
severe malalignment of the atlantoaxial joint.
German et al. [4] reported 21 cases (9.7%) of vertical axis fractures (16 coronal, 5 sagittal) in 208 cases
of upper cervical trauma. Some of coronal cases would
surely be classified as atypical hangman’s fractures by
other authors. The authors claimed good results with
conservative management but provide no patient-based
outcome measures.
Korres et al. [10] published axis body fractures in
11% of 172 cases of axis trauma. Additionally, these
authors also distinguish isolated fractures of the “lateral mass” (2%) and “miscellaneous” fractures (19%).
The treatment involved skeletal traction in bed for
2–6 weeks followed by immobilization in Minerva or
halo-vest. They obtained satisfactory results, however,
no functional outcome measures were provided.
Another article by the same author [11] reported 14
cases of avulsion fractures due to extension injury
treated conservatively by external immobilization.
Benzel et al. [1] reviewed 15 cases of axis body fractures (12 coronal and 3 sagittal) and dealt with possible
biomechanics involved in traumatic mechanisms. Based
on evaluation of these two groups, the authors proposed
a three-category classification. They suggested adding
type III odontiod fractures and atypical hangman type
fractures into the category of C2 body fractures. No
recommendations concerning treatment strategy based
on such classification have been proposed.
Taller et al. [23] included two cases of complete avulsion of posterior axis wall into the series of hangman’s
fractures. CT-guided transisthmic posterior fixation using
lag screws allowed safe reduction of fracture gap running
through C1/C2 joints and provided immediate stability.
Burke et al. [2] reports 31 miscellaneous fractures
including 21 tear drop fractures. This number stands
out in terms of incidence and it is most probably a matter of classification criteria.
with approximately 20–25% of them with concomitant
craniocerebral injury.
13.3 Radiology
Radiological evaluation is similar to other UCS injuries. Plain radiographs are performed in self-presenting
patients as a first-line assessment and usually only
identify dislocations but never delineate the exact fracture pattern (Fig. 13.1). Again, thin sliced CT
with reconstructions is the mainstay when it comes to
defining the exact fracture and dislocation morphology
(Fig. 13.2). MRI evaluation is mandatory to depict
the status of ligamentous structures and to exclude neural compromise and/or other level soft tissue injury
(Fig. 13.3). Other more sophisticated investigations
(dynamic films in cooperating individuals, dynamic CT
and/or MRI, MRA, and CTA) are added if necessary.
13.4 Treatment Strategy and Our Preference
Most authors prefer conservative treatment in so called
“miscellaneous fractures”; however, their approach
slightly differs according to specific fracture pattern.
13.2 Clinical Symptoms
As with other UCS injuries, the majority of admitted
patients may only have nonspecific neck pain frequently
radiating to the occiput and some range of motion
limitation. Some of them guard their neck against pain
by holding their head up with hands. Neurological
deficits are rarely seen, however, if present, can vary
from mild cranial nerve palsies to pentaplegia and/or
coma. This is more often seen in polytrauma victims
Fig. 13.1 Plain laterogram showing fracture of C2 body with
anterior C2-3 dislocation
13.4 Treatment Strategy and Our Preference
ab
Fig. 13.2 Axial CT depicting the course of oblique fracture.
The same patient from Fig. 13.1
As mentioned previously, our strategy is more
aggressive in case of instability visible on admission
radiographs or provoked by dynamic films in cooperating patients. Nonreducible fracture dislocations, especially those extending into articular surfaces or
compressing neural structures have to be considered for
199
surgical correction with regard to long-term outcome
and correct coronal and sagittal spine profile. Generally,
we divide miscellaneous fractures into two main groups
– fractures of C2 vertebral body and the others.
13.4.1 Coronal Axis Body Fractures
Many authors consider these patterns as “atypical” or
“unusual” hangman’s fractures [15, 20, 21, 23]; some
separate them as a distinct category of C2-body trauma
[1, 4]. Hangman’s fractures often involve at least some
part of posterior wall of the C2 body and therefore, a
clear border separating both categories cannot be identified. The exact site of the fracture ranges from small
infractions of the inferolateral aspects of the axis anterior column (Fig. 13.4) to complete posterior wall
avulsions with anterior extensions through superior
facet joints, transverse processes/vertebral foramina
(Fig. 13.5). The superior fracture line leaves the dens
attached to the anterior fragment. The inferior line runs
through the inferior endplate. Fractures running
through the anterior aspect of the axis should be considered either as a transverse fracture of C2 body or
type III fractures of the dens (Fig. 13.6). With the
majority of these fractures presenting with asymmetry,
Fig. 13.3 Sagittal MRI in T2
sequence in two different
patients. (a) Simultaneous
comminutive fracture of C2
body and luxation fracture at
the level of C7-T1 causing a
transverse spinal cord lesion.
(b) Unstable comminution of
C2 body endangering the
spinal cord
200
a b
a
b
Fig. 13.4 CT of coronal
fracture of C2 with partial
involvement of posterior wall
(more atypical hangman’s
type). (a) Only partial one
sided posterior wall
involvement. (b) Nearly all
the posterior wall is abrupted
13 Miscellaneous C2 Fractures
Fig. 13.5 Stable coronal C2
fracture involving important
part of posterior body wall
(more fracture of the C2
body) which was successfully
treated in Philadelphia collar.
(a) Sagittal MRI. (b) Axial
CT scan
Fig. 13.6 CT in coronal plane showing transverse C2 body frac-
ture (can be classified as deep type III odontoid fracture)
cases with no clear classification can easily be
encountered.
13.4.1.1 Our Preference
Vertical fractures of C2 vertebra (i.e., hangman’s fractures, atypical hangman’s fractures, and coronal C2
body fractures) are clearly a group of trauma with
smooth spectrum of patterns and corresponding biomechanics. Although there is an obvious tendency towards
external immobilization in the English-speaking literature, we prefer early anterior surgery in unstable cases
[21]. It provides immediate stability and also a chance to
reduce any displaced fragments (Fig. 13.7). In stable
fractures (disc not injured) with fracture distraction
greater than 3 mm on initial CT scans, reduction of
13.4 Treatment Strategy and Our Preference
a
c
b
Fig. 13.7 Coronal split
fracture of C2 body treated
with anterior graft and plate
fusion. (a) CT sagittal
reconstruction demonstrating
the fracture dislocation.
(b) MRI in T2 sequence
showing the traumatic C2-3
disc involvement. (c) Anterior
graft and plate fusion. Note
bicortical screw purchase
201
fracture gap can be better achieved by posterior approach
using transpedicular lag screws [12]. We [23] showed a
very safe method of CT-guided screw placement, however, indications for posterior procedure remain limited
(as was described in Chap. 12).
and/or oblique (Fig. 13.8). Superior aspect of the fracture
plane is located close to the base of dens or within the
medial aspect of the superior facet joint whereas inferiorly, the fracture often involves the C2-3 disc space. High
velocity axial load through the vertex of the skull is the
major causative force and severe craniocerebral trauma
is a common-associated injury [4]. However, pure axial
loading usually results in Jefferson burst fracture of the
13.4.2 Sagittal Axis Body Fractures
atlas. This means that additional shear forces [8], pre-
impact lateral bending or rotation in C1-2 joints are necSagittal pattern is not limited to the axis body, but it often
involves true axis pedicles and also the area covered by
superior facet joint. The fracture is frequently unilateral
essary to create this injury. These forces leave traces such
as infractions of the base of the dens, unilaterality of frac-
ture site and anteroposterior displacement of fragments.
202
a
cd
b
Fig. 13.8 Sagittally oriented
C2 body fracture. (a) Axial
CT scan. (b) Vertebral body
split visible on coronal CT
reconstruction. (c) Fusion in
malposition on axial CT scan
(d) “Fat C2 body sign” and
incomplete spontaneous C2/3
fusion on lateral radiograph 6
months after the injury
13 Miscellaneous C2 Fractures
13.4.2.1 Our Preference
Frequently, fracture union can be achieved by conservative means [3] as there is a large portion of cancellous bone involved. However, cases of severely
malaligned C1-C2 joint should be considered for C1-C2
fusion due to poor functional outcomes (Fig. 13.9).
13.4.3 Transverse Axis Body Fractures
“Deep” type III odontoid fractures should be mentioned
here as several authors [1, 4] advocate their re-assign-
ment to the group of axis body fractures. These fractures
surely run through the superior part of the C2 body, however, they separate the dens from the posterior elements
and clinical consequences of this functional issue provide
a strong argument for their assignment to the odontoid
group. True transverse axis fractures are extremely rare,
Fig. 13.9 Axial CT of oblique sagittal C2 body fracture extend-
ing to the upper facet
13.4 Treatment Strategy and Our Preference
abc
203
they usually involve extension mechanisms and leave the
odontoid process connected to the posterior elements [9].
The major difference between the groups is a potential
for dislocation (and thus, spinal cord compression). Type
III odontoid fractures are quite stable, but true transverse body fractures are frequently unstable. Extension
mechanism of injury makes them prone to associated
discoligamentous disruptions of the C2/3 intervertebral
connection. To illustrate the aforementioned diversity of
axis fractures, it is interesting to include a case of Maki
[14] with a “chance-type” fracture produced by bending
over anterior fulcrum (steering wheel).
13.4.3.1 Our Preference
As mentioned in Chap. 11, our inclusion criterion for a
fracture to be considered a type III odontoid fracture,
is that the fracture line has to reach at least one superior articular surface, cranially. However, the caudal
border distinguishing between type III odontoid fracture and horizontal fracture of the body has not been
established up to now. Perhaps, those injuries, where at
least one fracture line is located below the C2 upper
facet, can be classified as C2 body fractures as well.
Despite a large fracture surface area, they are often
unstable and incapable of maintaining sagittal alignment. In unstable injuries where the horizontal fracture
line does not reach the C2-3 disc space simultaneously
but with lack of substantial amount of bone available at
the C2 base for direct odontoid screw purchase, we
prefer a posterior fixation and fusion (Fig. 13.10). If
there is sufficient inferior bone present at the base of
C2 body, then the double screw anterior odontoid
fixation can be performed. Additional anterior graft
and plate can supplement the construct in cases of
simultaneous C2-3 disc rupture. Limits of previously
described procedures are written in the section
“Specific techniques” of Chap. 6.
13.4.4 Burst Fractures of Axis Body
Multiple fragment injuries are a result of extreme axial
loading as a primary force. Axis body and the pedicles
are strong and this pattern is rare as most axial loads
result in Jefferson fractures of atlas or subaxial spinal
injury. As in sagittal patterns, shear forces and/or rota-
tion and/or lateral bending help to transfer enough
force through the lateral masses of the atlas. High
velocity increases the probability of burst fractures,
even in cases with concurrent disruption of atlas ring.
13.4.4.1 Our Preference
Conservative treatment using external immobiliza-
tion is often a reasonable treatment option; however,
in polytrauma patients who are unconscious and/or
dependent on mechanical ventilation, posterior surgical
stabilization can dramatically increase their mobility
when compared to restrictions offered by cranial trac-
tion or halo-vest fixation. The other important positive
factor is much improved respiratory care (Figs. 13.11
and 13.12). Also, in elderly patients, surgical fixation
and fusion (Fig. 13.13) can offer a significant advan-
tage over a halo-vest immobilization (See Chap. 6).
Fig. 13.10 Unstable horizontal fracture of C2 body disconnect-
ing the odontoid from posterior elements treated with posterior
graft and transarticular screw fusion. (a) Fracture reduced under
traction. (b) Redislocation of the fracture after traction release.
(c) Postoperative status
204
a
b
c
abc
13 Miscellaneous C2 Fractures
Fig. 13.11 Comminution of C2 body extending from odontoid
to the vertebral base in an unconscious polytrauma patient with
unstable chest on ventilatory support. (a) Axial CT showing the
comminution. (b) Intraoperative image. (c) C1-3 fixation with
modular fixator
Fig. 13.12 Another polytrauma, unconscious patient with C2
body comminution and dominant odontoid type fracture and AA
instability. (a) CT in sagittal reconstruction. (b) CT in coronal
plane. (c) Permanent fixation C1-3 with prolonged Harms fix-
ator to C3 lateral mass screws
13.4 Treatment Strategy and Our Preference
a
c
d
b
Fig. 13.13 Comminuted C2
fracture in old patient who
refused the halo-vest offer.
(a) Sagittal reconstruction
showing C2 body comminution. (b) Coronal reconstruction depicting concurrent left
side facet damage. (c)
Intraoperative view with
fixator in place augmented by
posterior interlaminar
autologous bone grafts. (d)
Postoperative lateral film
205
13.4.5 Tear Drop Fractures
stable. The ability to support head is not significantly
altered and there is no danger of spinal cord injury.
Flexion with axial loading or extension with distraction are the major causes of tear drop fractures.
Treatment is focused on the discoligamentous injury at
the C2/3 segment and C2-3 fixation and fusion is a
method of choice (Fig. 13.14). Despite this, some
authors prefer external immobilization [11].
13.4.6 Non-Hangman Injuries to Lamina
and Spinous Process
Direct trauma is probably the only cause in otherwise
healthy individual. The spinous process of axis supports extensive muscular structures, but fractures
located posterior to inferior facet joints are considered
Treatment with a hard collar is sufficient as there is no
risk of joint incongruence and later degeneration.
These fractures are, probably, highly underreported in
the literature as they usually do not require a referral to
a specialized center.
Their follow-up is also unclear.
13.4.7 Fractures of the Superior Facet Area
Fracture lines often run through the area supporting
superior facet surface (some authors speak about “lateral mass,” “articular mass,” or “superior articular process”). Apart from transverse/coronal fracture line
206
ab
Fig. 13.14 Tear drop
fracture with posterior
dislocation. (a) Preoperative
lateral film. (b) Graft and
plate fusion on lateral X-rays
13 Miscellaneous C2 Fractures
extensions and sagittal/burst local patterns, there is
also a distinct type of unilateral impression fracture.
Trabecular bone mass underlying the superior facet
joint collapses and becomes dense on plain x-ray. This
is needed to hold appropriate alignment in coronal
plane. In such situations, it is reasonable to consider a
temporary C1-3 fixation in order to maintain adequate
alignment.
fracture is a result of milder axial loads in cases similar
to sagittal/burst fractures. It is likely to be underdiagnosed as a standalone injury; however, there is a strong
association with odontoid fractures with lateral displacement, according to the literature [8, 18]. The pri-
13.4.8 Fractures Through the Transverse Foramen
mary treatment is usually conservative. Cases with
odontoid fractures can be treated by anterior odontoid
screw fixation. C1-C2 fusion is reserved for cases with
painful C1/2 joint due to incongruence and/or subsequent degenerative changes.
Extensions into the transverse process and vertebral
foramen are a frequent finding, especially in coronal
fracture patterns. Although mostly asymptomatic,
there are reports of severe consequences of a vertebral
artery injury [13, 16, 17, 19]. Some authors performed
intraoperative angiograms to detect the injury and to
13.4.7.1 Our Preference
increase the safety of fragment reposition [22].
The majority of fractures of superior facets are a part
of differently classified injury. As mentioned earlier,
type III odontoid and atypical hangman-type fractures
13.5 Combination C1-2 Fractures
often involve the articular surface. However, although
rare, there is also an injury pattern where the axial
load is transferred symmetrically to the articular pillars of C2 (without atlantal bursting) and fracturing
of only the upper facets with eventual body extension (Fig. 13.15). Those can be hardly treated conservatively because stable symmetrical distraction
As it is described in Chap. 14, the treatment choice of
combined C1-2 fractures is dictated by the most important instability in each individual case. If the miscellaneous fracture type is the more unstable part of the
injury, then the treatment follows the above-mentioned
recommendations.
References
a
de
bc
207
Fig. 13.15 Simultaneous injury of C2 and subaxial spine (patient from Fig. 13.3a). (a) Fracture of C2 body and posterior C3 arch on CT
reconstructed image. (b) C2 stability in flexion. (c) Extension showing instability – dislocation. (d) CT in coronal plane reconstruction
clearly documenting both articular pillar fractures. (e) Plain lateral radiograph showing C1-3 temporal fixation in reduced position. The
360° reduction-fixation for luxation fracture at the level C7-T1 performed during the first stage procedure
References
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3. Fujimura, Y., Nishi, Y., Kobayashi, K.: Classification and
treatment of axis body fractures. J Orthop Trauma 10,
536–540 (1996)
4. German, J.W., Hart, B.L., Benzel, E.C.: Nonoperative management of vertical C2 body fractures. Neurosurgery 56,
516–521 (2005). discussion 516–521
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axis fractures. Analysis of management and outcome in 340
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(1997)
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