Klippel-Feil syndrome associated with pneumatocyst of the right cervical rib.

Abstract: A patient with Klippel-Feil syndrome reported with a pneumatocyst of the proximal epiphysis of a right cervical rib. There was no additional skeletal abnormality except for fusion of the C3 and C4 vertebral bodies. To the best of our knowledge, this is the first reported instance of this particular association.

Key Words: cervical rib syndrome, cervical vertebral anomalies, Klippel-Feil syndrome

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Klippel-Feil syndrome (KFS) is a congenital fusion of the cervical vertebrae that may involve two segments: a congenital block vertebra, or the entire cervical spine. Typically, KFS results from failure of the normal segmentation of the somites during weeks 3 to 8 of gestation. The prevalence of KFS is unknown, possible because it is not often expressed clinically.

Although congenital segmentation defect or fusion of any of the cervical vertebral bodies is commonly referred to as KFS, this syndrome is a clinical and radiologic entity with numerous associated anomalies and a variety of complications including those of the cardiovascular, renal, and musculoskeletal systems. Cervical ribs have also occasionally been reported in the context of KFS. (1)

Pneumatization of calvarial and upper cervical bones is a rare entity that commonly results from habitual Valsalva maneuvers. (2) Some pathologic processes, including osteomyelitis, osteonecrosis, neoplasm, or trauma, can cause intraosseous gas collection. Pneumatocyst is another form of intraosseous gas collection that has been reported in the ilium, sacrum, and vertebrae (3-5) and yet is rarely found in other bones. (6,7) We present a case with cervical vertebral fusion at a single level associated with a pneumatocyst of the right cervical rib. To the best of our knowledge, this is the first reported instance of this particular association.

Case Report

A 17-year-old female patient who presented with pain and limited movement in her neck was admitted for CT evaluation. Neurologic examination did not indicate any abnormality. A lateral cervical radiograph revealed fusion of C3 and C4 vertebral bodies (Fig. 1) suggesting Klippel-Feil syndrome. The other vertebrae and all posterior elements were normal. An anteroposterior radiograph of the cervical region revealed a right cervical rib and a pneumatocyst of the proximal epiphysis (Fig. 2). CT confirmed the right cervical rib and its articulation with the C7 vertebra. CT also showed a medullary air density homogenous and well-demarcated cyst, 11 X 11 mm in size, in the proximal epiphysis of the right cervical rib. No additional bone or soft tissue abnormality was seen except for fusion of the C3 and C4 vertebral bodies on CT (Fig. 3). No systemic or hematologic abnormality was detected on clinical and laboratory examinations.

Discussion

Feil (8) distinguished the KFS into three morphologic groups in 1919: Type 1 is described as massive fusion of the cervical spine, type 2 is present when fusion of one or two vertebrae occurs, and type 3 occurs when thoracic and lumbar spine anomalies are associated with type 1 or type 2 KFS. The extent of vertebral fusion along the spine was the basis for Feil's original classification of KFS. Although a few authors have maintained that a patient must exhibit the full clinical triad as well as possess fused cervical vertebrae to merit this designation, some references report that any patient who has failure of segmentation of two or more cervical vertebrae may be categorized as affected by KFS. (9) However, in a more recent and meticulous study, Clarke et al (10) suggested a new classification for KFS, based on underlying cause. In their description of four new KFS types, any isolated cervical fusion, including single fusion at variable positions, except C1-C2, is referred to as KFS class 3, corresponding to type 2 KFS in previous classifications.

[FIGURE 1 OMITTED]

Many patients with KFS have a normal appearance, and the syndrome is diagnosed through incidental roentgenograms. Deafness, synkinesia, and genitourinary and cardiorespiratory abnormalities are common associating manifestations of KFS. Among the many associated malformations that have been described in patients with KFS are Sprengel deformity, cervical ribs, webbed neck (pterygium colli), hemivertebrae, spina bifida, and kyphosis or scoliosis. Cervical ribs occur in 12 to 15% of patients with KFS. (11) When evaluating a patient with neurologic symptoms, the presence of a cervical rib and associated thoracic outlet syndrome should be investigated.

[FIGURE 2 OMITTED]

The cervical rib is a supernumerary rib arising from a cervical vertebra or elongated transverse process of the 7th cervical vertebra articulated to the first rib or ended freely. Cervical ribs may vary in length and may be connected to the first rib by a fibrous band. A cervical rib may cause symptoms by narrowing the space between the posterior aspect of the first rib and anterior scalene muscle through which the nerves and subclavian artery pass to enter the axilla.

Pneumatocyst in various bones has been previously reported; (3-7) however, to the best of our knowledge, there is no report regarding pneumatocyst in the ribs or cervical ribs. Calvarial hyperpneumatization and associated pneumatization of the first three cervical vertebral bodies were reported by Turowski et al. (2) In addition, there are reports detailing pneumatization of the calvarial bones, but pneumatization or pneumocyst of the bones in patients with KFS has not, to our knowledge, been reported. Since our patient had no additional systemic or hematologic disease, it is not possible to predict the exact cause of this entity. The young age of the patient and non-weight-bearing factor, combined with the absence of osteodegenerative changes in this accessory articulation (between the cervical rib and vertebra) exclude a probable degenerative pathology. Being aware of variable manifestations of this syndrome, a pneumatocyst in the cervical rib may be an associated finding in KFS. However, precise confirmation of this suggestion requires new additional cases.

[FIGURE 3 OMITTED]

To the best of our knowledge, this is the only case demonstrating a pneumatocyst of a cervical rib in association with KFS. It is possible that a pneumatocyst in a cervical rib may be manifested as in the other numerous anomalies in KFS. Although its clinical significance may be debated, this unique abnormality is worthy of recognition.

References

1. Konstantinou DT, Chroni E, Constantoyiannis C, et al. Klippel-Feil syndrome presenting with bilateral thoracic outlet syndrome. Spine 2004;29:E189-E192.

2. Turowski B, Juergen R, Raab P, et al. Cutaneous emphysema and craniocervical bone pneumatization. AJNR Am J Neuroradiol 2001;22:1398-1400.

3. Arslan G, Ceken K, Cubuk M, et al. Vertebral pneumatocysts. Acta Radiol 2001;42:20-23.

4. Catalano O, De Rosa, F, Muto M. Intraosseous pneumatocyst of the ilium: CT findings in two cases and literature review. Eur Radiol 1997;7:1449-1451.

5. De Rosa F, Catalano O. Intraosseous pneumatocyst of the sacrum: report of a case. Radiol Med (Torino) 1996;91:805-806.

6. Linker CS, Peterfy CG, Helms CA. Case report 844. Intraosseous pneumatocyst of the clavicle. Skeletal Radiol 1994;23:315-316.

7. Kamba M, Ohuchi Y, Ogawa T, et al. Intraosseous pneumatocyst of the scapula. Br J Radiol 2000;73:658-660.

8. Feil A. L'absence et la diminuation des vertebres cervicales (etude cliniqueet pathogenique): le syndrome dereduction numerique cevicales. Theses de Paris, 1919.

9. Ulmer JL, Elster AD, Ginsberg LE, et al. Klippel-Feil syndrome: CT and MR of acquired and congenital abnormalities of cervical spine and cord. J Comput Assist Tomogr 1993;17:215-224.

10. Clarke RA, Catalan G, Diwan AD, et al. Heterogeneity in Klippel-Feil syndrome: a new classification. Pediatr Radiol 1998;28:967-974.

11. Warner WC. Pediatric Cervical Spine: Campbell's Operative Orthopedics. Canale ST (ed.). Philadelphia, Mosby, 10th ed, 2003. pp 1737-1742.

We must be willing to let go of the life we have planned, so as to have
the life that is waiting for us.
--Joseph Campbell

Alpay Haktanir, MD, Bumin Degirmenci, MD, Ramazan Albayrak, MD, Murat Acar, MD, and Aylin Yucel, MD

From the Department of Radiology, Afyon Kocatepe Universitesi, Afyon, Turkey.

Reprint requests to Dr. Alpay Haktanir, Afyon Kocatepe Universitesi, Tip Fakultesi, Radyoloji AD, Yzmir yolu 7. km, 03120, Afyon, Turkiye. Email: [e-mail]

Accepted July 7, 2005.

RELATED ARTICLE: Key Points

* Pneumatization in bones is a very rare entity that commonly results from habitual valsalva maneuvers and some pathological processes including osteomyelitis, osteonecrosis, neoplasm, or trauma.

* Klippel-Feil syndrome is a clinical and radiologic entity with numerous associated anomalies and a variety of complications including cervical ribs.

* Pneumatization of a cervical rib, as far as we know, was not reported before solely or in association with Klippel-Feil syndrome; therefore, our case may have coincidental findings and the confirmation of any association requires new additional cases.