Background
A 60-year-old Caucasian male came to the chiropractic clinic with neck pain during movement, especially upon lateral bending. He also complained of frequent tingling and numbness down his left arm for the past three years. There was no history of recent significant trauma. The patient had been in an auto accident about 20 years ago, and another about 30 years ago. The patient was being treated for Meniere's syndrome at the time.
The patient demonstrated a visible cervical scoliosis. Orthopedic examination revealed a positive cervical compression test with pain on the left at C7 and on the right at C6. Positive Adson's test on the left was judged to be due to taut scaleneus muscle groups on the left. Neurologic examination was unremarkable, and deep tendon reflexes were graded +2/+4 bilaterally. No loss of sensation or muscle strength was found in the extremities. The remainder of the physical examination was unremarkable.
From radiographs of the cervical spine, a left lateral listhesis of Cl upon C2 of approximately 5 mm was visualized, a result of hypoplasia or agenesis of the odontoid process of C2. (Figure 1) Left lateral bending results in accentuated left lateral listhesis of Cl upon C2. The left lateral mass of Cl projects over the left superolateral margin of C2 by a measurement of 8 mm. The right lateral mass migrates to the left and measures 10 mm of movement from the right superolateral margin of C2. The right lateral mass of Cl is shown to override the rudimentary odontoid process in the left lateral bending position. (Figure 2) Right lateral bending shows a 5-mm right lateral listhesis of C1 over C2. (Figure 3) When considering the total translation of Cl upon C2 from the left lateral flexed position, a total of 15-mm translation is noted. Synostosis of C2, C3, and possibly CA is also noted, and there is a suspected right lateral hemivertebra at C3, resulting in an acute right lateral cervical curvature. (Figures 4 and 5) There is minimal anterolisthesis of C1 upon C2 noted in flexion. (Figure 6) Approximately 10-12 mm of retrolisthesis of
Cl upon C2 is present in extension. (Figure 7) Discogenic spondylosis is noted at CA-C7.
Diagnosis
1. Odontoid agenesis or hypoplasia with resultant instability of C1 upon C2 in left and right lateral bending and upon extension.
2. Klippel-Feil Syndrome.
3. Lower cervical discogenic spondylosis.
Treatment
The attending chiropractor informed the patient of treatment options for the odontoid agenesis, consisting of surgical intervention. The patient refused referral to a neurosurgeon or an orthopedic surgeon and reported that he would not undergo surgery. Conservative manipulative procedures were instituted for the lower cervical and upper thoracic degenerative changes. The patient has responded well to these treatments and is now seen only intermittently, on an as-needed basis.
Discussion
Odontoid process hypoplasia or agenesis may be seen as an isolated condition or in combination with other findings that are related to a known syndrome, such as Klippel-Feil syndrome, Down's syndrome, Morquio's syndrome, or spondyloepiphyseal dysplasia. Odontoid hypoplasia is regarded as a rudimentary odontoid that projects just cephalad to the level of the C1/C2 joint. Agenesis of the dens is noted as complete absence of the dens.1,2
A physical description of the patient with Klippel-Feil syndrome is a short, webbed neck (pterygium coli), a low posterior hairline, and decreased range of motion. The full triad is seen in 52 percent of cases.1 Vertebral anomalies consist of two or more blocked vertebrae in the cervical and upper thoracic regions.1,3,4 The blocked vertebrae are responsible for a scoliosis, which is the most common feature in Klippel-Feil syndrome. (KFS) Platybasia of the skull and congenital elevation of the scapula (Sprengel's deformity) are also seen in one quarter of the cases.1 The etiology of hypoplasia or agenesis of the odontoid process of C2 is controversial. Developmental under-growth is one proposed theory. Another theory is early childhood trauma, resulting in aberrant growth (in the case of Os Odontoideum, trauma is thought to be a cause, with resultant nonunion of the fracture fragments).1,4,5
Stability of the upper cervical region must be assessed due to the possibility of neurologic compromise. Hypoplasia, or agenesis of the dens, can be associated with lateral translation of C1 upon C2 in the neutral posture. Lateral-bending AP open-mouth radiographs are utilized to assess the degree of instability, in the coronal plane, that may be present at the level of C1/C2. Normal lateral translation of Cl upon C2 measures no greater than 1.0 mm. Flexion and extension lateral cervical radiographs are useful to evaluate for sagittal translation of CT upon C2. Stress hypertrophy of the anterior arch of the atlas may be present as a result of the increased mechanical forces created in the upper cervical junction. Plain film radiographs are usually sufficient to make the diagnosis. Magnetic resonance imaging (MRI) or computed tomography (CT) are indicated when neurologic signs and symptoms are present to evaluate for associated or resultant central nervous system disorders.1,6,7,8 Neurologic disorders that may be found include Chiari malformations, syringomyelia, spinal cord atrophy in the event of spinal canal stenosis created by instability, and even splitting of the cervical spinal cord.9 Vertebral artery aneurysm complicating a case of KFS, as a result of instability at C1/C2, has been reported. This is a rare occurrence with only two cases having been reported.10 Abnormalities of the middle ear with conductive hearing loss due to middle ear malformations in patients with KFS have also been reported." Acute respiratory failure has been noted as the first sign of Arnold-- Chiari malformation in a patient with associated syrgomeyelia, Klippel-Feil syndrome, basilar impression, and platybasia.12
Treatment options for the case presented included:
1. Conservative management, excluding manipulation of the upper cervical region, as manipulation is contraindicated due to the presence or possibility of instability.
2. Surgical arthrodesis of the upper cervical vertebrae (ClC3) in the presence of ominous symptoms or hard neurologic findings.
Prophylactic arthrodesis was once practiced, but subsequent studies have found that the outcome assessments show no statistical difference in groups of patients managed conservatively and those that had arthrodesis. In a recent paper by Ramos et al., three cases of Os Odontoideum are discussed, with all patients being referred for orthopedic or neurosurgical consultation. One was recommended for arthrodesis. This patient had visual symptoms ("purple spots" upon extension of the cervical spine) but no positive orthopedic or neurologic findings. The other two patients presented in the paper had neck pain without positive orthopedic or neurologic findings.5 A study of long-term follow-up of patients with KFS and congenital scoliosis reported that o/dy (emphasis added) 22 percent (seven) of 32 patients had cervical or cervical-related symptoms. Two patients in the study required surgery due to cervical lesions. There was no significant difference in the degree of deformity and the average number of cervical vertebral fusions in symptomatic and asymptomatic patients. However, patients who had fusion to the cervicothoracic junction and patients with congenital stenosis of the cervical canal had greater incidence of symptoms.13
Conclusion
A case of odontoid hypoplasia or agenesis with Klippel-Feil syndrome was presented. The features of Klippel-Feil syndrome, associated spinal anomalies, and central nervous system abnormalities were briefly described. Findings of lateral instability of the upper cervical spine were present on left and right lateral bending A-P open-mouth radiographs, and its importance discussed. Treatment options available to patients with Os Odontoideum, dens hypoplasia, and upper cervical instability were discussed. Practicing chiropractors and their patients with Klippel-- Feil syndrome would be well served to utilize advanced imaging (specifically, MRI) to confirm or negate the presence of associated or co-existing abnormalities of the central nervous system. This should be done prior to commencement of manipulative therapy. An argument could also be made to utilize advanced imaging to exclude CNS abnormalities in all patients with Klippel-Feil syndrome who seek treatment from providers of manipulative therapy since the majority of these patients remain asymptomatic.13 Those who become symptomatic and present for care may be more likely to exhibit the associated CNS abnormalities as described above, have fusion into the cervicothoracic junction,13 or have secondary degenerative changes related to the synostosis.
References--
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10 David KM Copp AJ, Stevens JM, Hayward RD, Crockard HA. "Split Cervical Spinal Cord with Klippel-Feil Syndrome: Seven Cases. " Brain 1996 Dec; 11 9(Pt 6): 1859-1872.
11. Shimizu S, Kojima T, Morooka Y, Tanaka K Nakagau,nY, Kuroki M.
"Ertracraial1 Vertebral Artery Aneurysm Complicating Klippel FeiI Syndrome; Case Report. "No Shinkei Geka 1996 Oct;24(10):933-937.
12. Alverez D, Pequena I, Arias M, Valdez L, Pereiro I, De la Torre R. "Acute Respiratory Failure as the First Sign of Arnold-Chiari Malformation Associated with Syringomyelia. "Eur Respir J. 1995 Apr,8(4).661-663.
13. Theiss Sm, Smith MD, Winter RB. "The Long-Term Follow-Up of Patients with Klippel-Feil Syndrome and Congenital Scoliosis. "Spine 1997 Jun 1,22(11). 1219-1222.
Copyright American Chiropractic Association Jun 1999
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