CASE REPORT Kor J Spine 4(1):37-40, 2007 Congenital Spondylolytic Spondylolisthesis of Cervical Spine - A Case Report and Review of the Literature - Sung-Ku Park, M.D., Jung-Kil Lee, M.D., Yeon-Seong Kim, M.D., Soo-Han Kim, M.D. Department of Neurosurgery, Chonnam National University Hospital & Medical School, Gwangju, Korea Cervical spondylolytic spondylolisthesis is a rare congenital anomaly, defined as a corticated defect in the pars interar- ticularis with anterolisthesis of the same vertebra. Accompanied spina bifida and dysplastic changes of the vertebra firmly support the possibility for its congenital origin. Accurate diagnosis and discrimination of this rare congenital condition from traumatic injury or other pathological conditions in patients with neck pain is very important, especially after a trivial traumatic event, because the traumatic injury and pathological conditions are more serious and need more aggressive treatments. Thorough radiological evaluation with precautions mentioned above is essential. Conservative treatments are considered in the majority of the congenital spondylolytic spondylolisthesis, and surgical treatments are reserved for symptomatic and mechanically unstable lesions. The authors report a case of congenital spondylolytic spondylolisthesis of the sixth cervical vertebra which was treated by a conservative strategy based on mild symptoms and mechanical stability, with review of the literatures. Key Words: SpondylolysisㆍSpondylolisthesisㆍCongenitalㆍCervical spine INTRODUCTION logical examination was normal. Plain radiographs of the cervical spine revealed bilateral spondylolysis and spina bifida Cervical spondylolytic spondylolisthesis (CSS) is a rare clinical of C6 with grade I spondylolisthesis of C6 on C7 (Fig. 1), entity, that is, usually occurr at C62,3,12). It is very important but there was no evidence of mechanical instability on fle- to distinguish this congenital anomaly from traumatic injury xion and extension radiographs (Fig. 2). CT scan clearly or pathological bony erosion by neoplastic disease, because demonstrated well-corticated margins of the spondylolytic the latter condition is more serious and needs more definite defects and hypoplastic change of both pedicles with spina treatment than the former1,16). The exact diagnosis by meti- bifida of C6 (Fig. 3). The findings of acute fracture were culous radiological evaluation, especially with aid of simple not discovered in CT scan. The evidence of myelopathy or radiographs and computerized tomographic (CT) scan, is paravertebral soft tissue injury was not observed in cer- essential for adequate treatment4,14). vical magnetic resonance images (MRI), either (Fig. 4). The authors describe a case of congenital spondylolytic We performed conservative treatment on the base of the spondylolisthesis of C6 which was treated by a conserva- neurological and radiological stability. At two-year follow-up, tive therapy and review the clinical and radiological features he was free from posterior neck pain and resumed normal with consideration for optimal treatment options. activity. CASE REPORT DISCUSSION A 15-year-old male visited our institute for intermittent CSS is defined as a well-corticated cleft in the pars inte- posterior neck pain after trivial traffic accident 9 months rarticularis of the respective cervical vertebra, resulting in before. He was well-developed, and had no external defo- anterolistheisis of the same vertebra. The incidence of CSS rmity or trauma evidence on physical examination. Neuro- is very lower than that of lumbar spondylolisthesis, which Corresponding Author: Jung-Kil Lee, M.D. Address of reprints: Department of Neurosurgery, Chonnam National University Hospital, 8 Hak-Dong, Dong-Ku, Gwangju, 501-757, Korea Tel: +82-62-220-6606, Fax: +82-62-224-9865, E-mail: [email protected] 37 Kor J Spine 4(1) March 2007 Fig. 3. Axial CT scan (A) of the C6 (bone window) clearly indicates the well-corticated, smooth bony defects of the pars interarti- cularis (small arrows) and accom- panied spina bifida (large arrow). Sagittal 2-D reconstruction(bone window) images (B) of the cervical spine demonstrate bilateral linear defects at the pars interarticularis of C6 (arrow heads) with sclerotic borders. Fig. 1. Lateral (A) and both oblique (B) radiographs of the cervical spine show 3mm anterolisthesis at the C6-7 level (small arrow in A) associated with linear radiolucent defects at the pars interarticularis of C6(large arrows in A and B) with sclerotic borders. Anteroposterior (AP) view (C) shows associated spinal bifida at C6 (arrow head). Fig. 4. Abnormal high signal intensity in spinal cord or evi- dence of paravertebral soft tissue injury is not demonst- rated in axial (A) and sagittal (B) T2WI MRI of the cervical spine. hundred cases have been reported in the English language literature12). Generally, it is diagnosed as a incidental finding in the course of the routine radiological examinations for neck pain, especially after minor trauma5). Though the majority of the patients with CSS were within the normal range at neurological examination, they revealed various symptoms, Fig. 2. Cervical spine dynamic series of flexion(A) and extension (B) reveal no evidence of mechanical instability ranging from asymptomatic or mild neck pain to more serious 5,9) between C6 and C7. conditions in the previously reported cases . Although CSS has been reported to occur at any level except C1 and C7, 16) the most cases occurred at C6 with bilateral spondylolytic has been present in 5% of the general population . Since defect rather than unilateral, and mild spondylolisthesis and bilateral cervical spondylolysis with spondylolisthesis was first spina difida were accompanied in most reported cases13). described by Perlman and Hawes in 1951, only about one 38 Congenital Spondylolytic Spondylolisthesis of Cervical Spine SK Park et al. Radiological images including simple radiographs and CT by tumor14). scan, are essential for the diagnosis of CSS. A well-margin- Most patients with CSS have been treated effectively by ated articular mass cleft oriented obliquely to the plane of conservative measures including cervical collar brace and the facet joint, triangular pillar fragments, hypoplasia of the anti-inflammatory medication on the base of mechanical stability ipsilateral pedicle, and spina bifida were common findings in and their mild symptoms1,9,16). Surgical treatments should the literature4,16). Compensatory hypertrophy of the articular be reserved for cases of failed conservative measures, inst- process in the adjacent vertebrae and spondylolisthesis, us- ability due to the defect itself or secondary to trauma, cord ually less than 3 mm, were found7,13). Despite the inceasing or root involvement, and prevention of spondylolisthesis. use of MRI for trauma and various pathological conditions Anterior cervical fusion technique would be the favorable in spine, MRI was not helpful in the diagnosis of CSS. method6,10,11). However, prophylatic surgery is still controversial. However, it is useful for exclusion of other diseases4,14). Though the exact etiology for CSS is still open to argument, CONCLUSION many authors have supported its congenital origin1,5,8,13). Embr- yologically, a cervical vertebra develops from six chondrifica- CSS is a rare congenital anomaly involving mainly C6, tion centers during sixth week of gestation. The vertebral and most patients present with the mild posterior neck body is formed by two centers, whereas, four centers form pain without neurological deficit. Recognition of CSS from the posterior arch. At ten weeks' gestation, the four chond- traumatic injury is extremely important for preventing ina- rification centers of the posterior arch unite to form two ppropriate treatment and unnecessary surgery. Conserva- ossification centers on opposite sides of the midline. Each tive treatments are successful in the majority of patients, of these ossification centers forms a pedicle, a lateral mass, and the surgical intervention should be considered if cons- and a half of the lamina. Ossification proceeds with posterior ervative treatment is ineffective or there is a evidence of fusion of the lamina at age two years, and bony fusion of mechanical instability in the neuroradiological evaluation. the posterior arch with the vertebral body occurs between three and six years of age. Defects in this normal sequence of REFERENCES ossification result in the formation of posterior arch ano- malies. Therefore, the most likely etiology for the complex 1. 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