In October 2001, a forty-nine-year-old man with a thirty-year
history of ankylosing spondylitis presented with severe torticollis, a
chin-on-chest deformity, and a protruded tongue. These conditions had
developed three months before admission and had progressed rapidly over the
preceding four weeks. The patient reported no history of trauma to the head or
neck in the preceding months.
Neurological examination revealed generalized hyper-reflexia, sustained
ankle clonus, and positive Babinski signs. Muscle power was decreased (grade 3
of 5) throughout both the upper and lower extremities. The bowel and bladder
sphincters were not affected. In addition to the spinal deformity, the most
striking finding was that the tongue protruded, was immobile despite voluntary
efforts to move it, and was coated with thick layers of whitish secretions. No
wasting or fasciculation was detected. The patient was unable to speak, chew,
or swallow and he continuously drooled saliva. Because of the tilt and
rotation of the head, the face was so disfigured that the patient could not
raise the eyelid of the right eye. Nutrition was provided with nasogastric
feeding, and the airway was secured by constant suction.
A lateral plain radiograph showed severe anterior dislocation of the atlas
on the axis that markedly compromised the spinal canal
(Fig. 1-A). A sagittal
reconstruction of a computed tomographic scan revealed marked anterior and
vertical migration of the dens with substantial cervicomedullary compression
(Fig. 1-B). A coronal computed
tomographic reconstruction showed extensive erosion of the C1-C2 facet joints
with marked rotatory subluxation (Fig.
1-C).
We decided to gradually correct the multiple-plane deformity. First,
halo-dependent traction was used with 2 kg of weight applied anterolaterally
to correct the rotational displacement. Three days later, 2 kg of vertical
traction was added anteriorly to correct the chin-on-chest deformity while the
anterolateral traction was decreased to 1.5 kg to maintain the corrected
position. On the thirteenth day, the patient was able to retract the tongue
completely and open the right eye, as the head tilt and rotation had been
corrected. He could move the tongue freely and was able to speak again.
Sixteen days following the commencement of traction, he underwent
craniocervical arthrodesis from the occiput to C6 with the use of allografts,
plates, and wires. Following reduction and surgery, the signs of cervical
myelopathy (weakness and clonus) and hypoglossal nerve palsy (dysphagia,
dysarthria, and dysphonia) all rapidly resolved. The patient was able to eat
solid foods without choking and could articulate clearly. Two weeks after the
craniocervical arthrodesis, lumbar osteotomies were performed to correct a
thoracolumbar kyphosis. He continued to wear a body cast that incorporated the
halo ring for a total of 4.5 months. At 2.5 years after surgery, he was able
to walk with the aid of a walker, and radiographs confirmed a solid
occipitocervical fusion without loss of correction
(Fig. 2).
The precise mechanism of the hypoglossal nerve palsy in our patient
is not known. It may have been caused by either mechanical traction on or
vascular insufficiency of the hypoglossal nerve. The hypoglossal nerve exits
the skull base anterior to the occipital condyle. It then travels through the
hypoglossal foramen, following a vertical course inferiorly just lateral to
the jugular foramen to cross the anterior aspect of the lateral masses of
C1-C217. Macedo et
al.15 reported two
cases of bilateral hypoglossal nerve palsy due to vertical migration of the
dens as a result of late-stage rheumatoid arthritis. They proposed that the
hypoglossal nerves were directly compressed at the level of the C1 transverse
process. Kenrick et
al.13 contended
that anterior subluxation of C1 could injure the hypoglossal nerves
bilaterally as they exit from their canals while not affecting cranial nerves
IX, X, and XI, which emerge from the more lateral jugular foramen. Shim et
al.9 reported on a
patient with ankylosing spondylitis who had vertical migration of the dens,
and they concluded that vascular insufficiency was the main cause of the
medullary ischemia and bulbar symptoms. In our patient, the signs and symptoms
may have been due to mechanical traction on the hypoglossal nerves. When the
head tilt, rotation, and chin-on-chest deformity first developed, the patient
complained of a thick tongue with slurred speech. As the deformity progressed,
the paralyzed tongue was gradually forced out of the mouth. Subsequently, the
airway became markedly obstructed, placing the patient at risk for suffocation
and aspiration. Soon after successful reduction was accomplished with halo
traction, he was able to retract the tongue and the dysphagia and dysarthria
improved dramatically, suggesting that the tension on the hypoglossal nerve
had been relieved.
Graziano et
al.18,19
and Mehdian et
al.20 reported
successful reduction of cervical deformity with halo traction in patients with
rheumatoid arthritis and ankylosing spondylitis. Halo traction was used for
our patient for several reasons. First, it made it possible to address the
devastating deformity with readily available equipment. Second, judging from
the disease course, the dislocation had been present for a relatively short
duration (four weeks at the most), suggesting that the deformity was still
supple. Third, reduction in the presence of marked atlantoaxial rotatory
dislocation can be
risky21 and can be
hampered by difficulty with
intubation22.
Accordingly, the rotational deformity of the head was first corrected with the
anterolateral traction, after which the vertical traction was applied to
correct the anterior and upward displacement of the dens. During the
application of the traction, the patient was monitored closely with serial
neurological examinations to avoid additional cranial nerve or cord
injury23. The
weight and the vector force of the traction were adjusted frequently according
to the extent of the reduction and the patient's tolerance. We placed emphasis
on the duration and vector force of the traction rather than simply increasing
longitudinal traction to extend and derotate the neck.
In summary, gradual correction with halo-dependent traction followed by
occipitocervical arthrodesis was a safe and effective method for treating this
life-threatening atlantoaxial rotatory dislocation. ?
The authors did not receive grants or outside funding in support of their
research or preparation of this manuscript. They did not receive payments or
other benefits or a commitment or agreement to provide such benefits from a
commercial entity. No commercial entity paid or directed, or agreed to pay or
direct, any benefits to any research fund, foundation, educational
institution, or other charitable or nonprofit organization with which the
authors are affiliated or associated.