Elsevier

The Spine Journal

Volume 9, Issue 7, July 2009, Pages e1-e5
The Spine Journal

Case Report
Posterior arch defects of the cervical spine: a comparison between absent pedicle syndrome and spondylolysis

https://doi.org/10.1016/j.spinee.2009.01.006Get rights and content

Abstract

Background context

Abnormalities of the posterior arch are rare entities that are usually found incidentally on neck radiographs. Their radiographic appearance may cause them to be confused with more serious entities such as fractures, locked facets, and tumor-induced bony erosions. It is important to distinguish these posterior arch abnormalities from the other entities because the treatment is very different.

Purpose

Posterior arch defects of the cervical spine, including cervical spondylolysis and absent pedicle syndrome, occur rarely. In this case report, we describe three cases of posterior arch defects and present a review of the literature concerning the distinguishing features between spondylolysis and absent pedicle syndrome.

Study design

A case report and literature review of the posterior arch defects.

Methods

Two patients are presented who developed posterior neck pain after trauma. They had no neurologic deficits, but cervical radiographs suggested that they had a traumatic injury. Cervical spine computed tomography (CT) revealed absent pedicle syndrome and they were treated conservatively. Another patient is presented who developed worsening posterior neck pain and left shoulder pain. She had no history of significant neck injury. Cervical radiographs and CT showed bilateral spondylolysis of C6 vertebra and subluxation of C6 on C7. Because her symptoms were not relieved by conservative measures, we performed anterior cervical discectomy and fusion.

Results

We treated two patients with absent pedicle syndrome by conservative measures and one patient with cervical spondylolyis by surgical treatment.

Conclusions

Posterior arch defects were often confused with other disease entities. But, they have some distinctive features and such distinctive features may be helpful in confirming diagnosis and planning treatment. Furthermore, three-dimensional CT scan reconstruction provides comprehensive anatomic evaluation of the structures with an absent pedicle and the associated bony abnormalities.

Introduction

Abnormalities of the posterior arch are rare entities that are usually found incidentally on neck radiographs. Their radiographic appearance may cause them to be confused with more serious entities such as fractures, locked facets, and tumor-induced bony erosions. It is important to distinguish these posterior arch abnormalities from the other entities because the treatment is very different. There are two complexes of abnormalities related to posterior arch defects of the cervical spine. One is a congenital spondylolytic spondylolisthesis (spondylolysis), and the other is absent pedicle syndrome [1].

We report three cases of posterior arch defects and present a review of the literature concerning the distinguishing features between spondylolysis and absent pedicle syndrome.

Section snippets

Case 1

A 47-year-old woman was presented with posterior neck pain and right arm pain after a traffic accident. She had no history of posterior neck pain before the accident. Cervical spine films showed an enlarged neural foramen extending from C4 to C5 on the right side (Fig. 1, top left). Also, two-dimensional (2D) computed tomography (CT) showed the findings of right unilateral facet dislocation (Fig. 1, bottom left). But, three-dimensional (3D) CT scan revealed the absence of the right pedicle and

Review of the literature

Since bilateral cervical spondylolysis was first described by Perlman and Hawes [2] in 1951, only one hundred cases have been reported in the literature. Although cervical spondylolysis has been reported at all vertebral levels except C1 and C7, most reported cases have occurred at C6. The abnormality is almost always bilateral rather than unilateral and is associated with spondylolisthesis and spina bifida.

There have been fewer than one hundred published cases of absent pedicle syndrome since

Discussion

Spondylolysis and absent pedicle syndrome of the cervical spine are actually a complex of abnormalities in posterior arch development. They are similar to each other, but there are some distinctive differences between them.

Conclusion

Spondylolysis and absence of the pedicle are congenital anomalies of the posterior cervical spine. Their roentgenographic findings may be confused with other more serious entities that require either emergent therapy or extensive diagnostic testing and treatment. However, spondylolysis and absence of the pedicle have some distinctive features. These distinctive features may be helpful in confirming the diagnosis and planning treatment. Furthermore, 3D CT scan reconstruction provides

Acknowledgments

The authors thank the Department of Radiology, Chonbuk National University Medical School/Hospital for technical assistance.

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