Radiographic assessment of congenital C2-3 synostosis

Are Congenital Cervical Block Vertebrae a Risk Factor for Adjacent Segment Disease? A Retrospective Cross-Sectional CT and MR Imaging Study

Adjacent segment disease (ASDI) is a well-described complication of spinal fusion surgery that may ultimately lead to spinal stenosis and repeated surgical intervention. Although congenital block vertebrae also present with degenerative changes in the adjacent segments, this has not yet been systematically investigated. The aim of this study was to assess the presence and degree of ASDI in congenital cervical block vertebrae. Methods: A total of 51 patients with congenital vertebral fusion in one cervical segment were analysed in this IRB-approved retrospective cross-sectional study using available CT/MR imaging. Exclusion criteria were prior spinal surgery and the presence of additional hereditary abnormalities. We assessed the severity of degenerative changes using a sum score. The sum score for adjacent and non-adjacent segments was then divided by the highest possible degeneration score, which resulted in a ratio of severity for adjacent and remaining segments (ranging from 0 to 1). Results: Overall, 35 of 51 patients (68.6%) showed evidence of ASDI, and 34 of 51 patients (66.7%) also showed degenerative changes in the remaining segments. The severity score was significantly higher (p = 0.025) in the segments adjacent to the congenital block vertebrae (mean value 0.307) compared to the non-adjacent segments (mean value 0.188). Conclusions: Our results suggest that ASDI is also caused by congenital block vertebrae of the cervical spine.

Effect of Congenital C4-5 Synostosis on Adjacent Mobile Segments: Radiographic Assessment

STUDY DESIGN

Prospective case series.

PURPOSE

To assess the corporal morphology of the fused body and adjacent segment conditions.

OVERVIEW OF LITERATURE

It is known that two fused vertebral bodies take the similar shape of the single body with inwaisting, with or without caudal flaring of the fused body, and that the fused body can cause the fusion disease at the adjacent segment that can be a risk factor for potential neurological compromise.

METHODS

Radiograms of the 11 study subjects (six men and five women), aged 22-90 years who visited the outpatients' clinic for various neck complaints without trauma history were examined. C4-5 synostosis was an incidental finding in all the subjects.

RESULTS

All the fused bodies were inwaisted and had anterior caudal breaking but no interior corporal flaring. Adjacent segment disease was not found in eight patients aged <40 years. Disk degeneration was found at C3-4 and C5-6 in three patients each and at C6-7 in two patients. Disk degeneration was limited to the adjacent segments.

CONCLUSIONS

Degenerative disk changes are associated with the natural aging process, and the corporal morphology of the fused vertebral becomes inwaisted similar to that in the single vertebrae.

Radiological Assessment of the Effect of Congenital C3-4 Synostosis on Adjacent Segments

Study Design

Retrospective case series.

Purpose

To assess the effect of non-kyphotic aligned congenital C3-4 synostosis on the adjacent segment in 10 patients.

Overview of Literature

In the cervical spine, fusion disease at the adjacent motion segments may be a risk factor for potential neurological compromise and death.

Methods

Radiograms of 10 patients 13 to 69 years of age presenting with neck/shoulder discomfort or pain with or without trauma history were examined. C3-4 synostosis was found incidentally in all patients on routine examination radiographs of cervical spine.

Results

Adjacent segment disease (ASD) was not found in the three patients younger than 39 years of age. Five of the 10 (50%) patients, including a 67-year-old man, did not develop spondylosis in any of the cervical mobile segments. Spondylosis was observed only in the caudal 1-2 mobile segments in the remaining five patients. The youngest was a 40-year-old male who had spondylosis in the two caudal mobile segments (C4-5 and C5-6). Spondylosis was limited to the two close caudal mobile segments and was not in the cranial segments. Flaring of the lower part of synostotic vertebra associated with advanced narrowed degenerate disc was evident in five patients.

Conclusions

Mobile segment spondylosis in the individuals with congenital monosegment C3-4 synostosis over age of 40 years may be a natural manifestation of aging and is not solely an adjacent segment disease directly and fully related with congenital C3-4 synostosis.

Radiographic Assessment of Effect of Congenital Monosegment Synostosis of Lower Cervical Spine between C2-C6 on Adjacent Mobile Segments

Study Design

A prospective radiographic study of cervical spine with congenital monosegment fusion.

Purpose

To evaluate the effect of cervical synostosis on adjacent segments and the vertebral morphology.

Overview of Literature

There are numerous clinical studies of adjacent segment disease (ASD) after monosegment surgical fusion. However, there was no report on ASD in the cervical spine with congenital monosegment synostosis.

Methods

Radiograms of 52 patients, aged 5 to 90 years, with congenital monosegment synostosis (CMS) between C2 and C6, who complained of neck/shoulder discomfort or pain were studied. 51 were normally aligned and one was kyphotically aligned.

Results

Spondylosis was not found in the patients below 35 years of age. Only 12 out of 24 patients with normally aligned C2-3 synostosis had spondylosis in 19 more caudal segments, and only one at C3-4. A patient with kyphotic C2-3 had spondylolysis at C3-4. In 8 patients with C3-4 synostosis, spondylosis was found in only 9 caudal segments (4 at C4-5, 4 at C5-6, and 1 at C6-7). The caudate C4-5 disc was the most liable to degenerate in comparison with other caudate segments. Caudal corporal flaring and inwaisting of the synostotic vertebra were the features that were the most evident. In 2 of 9 C4-5 and 7 out of 10 C5-6 synostosis patients, spondylosis was found at the two adjacent cephalad and caudate segments, respectively. Only corporal inwaisting without flaring was found. In all cases, spondylosis was confined to the adjacent segments. More advanced spondylosis was found in the immediate caudal segment than the cephalad one.

Conclusions

It is concluded that spondylosis at the mobile segments in a synostotic spine is thought to be a fusion-related pathology rather than solely age-related disc degeneration. Those data suggested that CMS definitely precipitated the disc degeneration in the adjacent segments.

Progressively unstable c2 spondylolysis requiring spinal fusion: case report

Cervical spondylolysis is a rare condition defined as a corticated cleft at the pars interarticularis in the cervical spine. This is the case of C2 spondylolysis demonstrating progressive significant instability, which was successfully treated by anterior cervical discectomy and fusion (ACDF) with cervical anterior plate. We describe a 20-year-old female with C2 spondylolysis presenting with progressive worsening of neck pain associated with progressive instability at the C2/3 segment. The progression of instability was well-documented on flexion-extension cervical spine x-rays. She was successfully treated by C2/3 ACDF with anterior cervical plate. Her preoperative significant neck pain resolved immediately after the surgical intervention. She was completely free from neurological symptoms at 1-year postoperative follow-up. We also review the literature and discuss 24 reported cases with C2 spondylolysis. When planning treatment, we should make sure to differentiate this pathology from acute traumatic fracture, which is a hangman's fracture. Assessment of C2/3 instability associated with neurological deficits is extremely important to consider management properly. C2/3 ACDF with cervical plate is biomechanically viable, less invasive, and provides adequate surgical stabilization for unstable C2 spondylolysis.