Craniocervical junction abnormalities(CJA) in pediatric patients with a genetic disorder

Cantürk A., Yarol R. C., Yaşar E., Güleryüz Uçar H.

European Congress of Radiology, Vienna, Avusturya, 1 - 05 Mart 2023, cilt.1, sa.1, ss.1-2

  • Yayın Türü: Bildiri / Tam Metin Bildiri
  • Cilt numarası: 1
  • Doi Numarası: 10.26044/ecr2023/c-16806
  • Basıldığı Şehir: Vienna
  • Basıldığı Ülke: Avusturya
  • Sayfa Sayıları: ss.1-2
  • Dokuz Eylül Üniversitesi Adresli: Evet

Özet

Title :

Craniocervical junction abnormalities(CJA) in  pediatric patients with a genetic disorder

 

PURPOSE:

To evaluate craniocervical junction abnormalities(CJA) in pediatric patients with a genetic disorder

 

 

METHODS or BACKGROUND:

The craniovertebral junction connects the skull and cervical spine. İt is a biomemechanically complex articulation consist of the occipital condyles (Oc) the atlas (C1) and axis (C2) [1].

 

Children are more susceptible to craniocervical instability due to their larger head size, flexible joints and ligaments, and a shallower facet joint. [2] .

 The distance between the anterior surface of the dens and the posterior surface of the tubercle in children should be less than 5 mm. This space is also known as 'Predentate space'. If the predentate space is measured more than 5 mm, we should consider atlantoaxial instability. However, in chronic atlantoaxial conditions (eg.Down syndrome, congenital anomalies), the predentate space is less valuable [1]. (Figure 1 )

 

 

There are several ways a subluxation can occur . Anteroposterior subluxation , rotatory subluxation,  vertical subluxation and lateral subluxation [3] . Rotatory subluxation is characterized into four different types according to the the Fielding and Hawkins classification (Figure 2 )

 

CJA  are generally due to one of three biomechanical features , instability, deformity and neuraxial compression[1] . İnstability   occurs when the structural compromise of the Oc-C1-C2 articulation allows movement outside physiological limit [1]  . Generally, ligament laxity is responsible for instability and this condition more common in atlantoaxial joint [4] . Espicially in the Down Syndrome population the ligament laxity due to intrinsic collagen defects or chronic inflammation leading to weakness and cause instabiliy[2] (Figure 3 ) .

  Anatomical and rotational deformity can also contribute to craniocervical junction abnormalities[1]

In achondroplasia there is a marked discrepancy in relative size between skull vault and the skull base [1] . Since  the skull base forms by endochondral ossification whereas the skull vault by membranous ossification, As a result of this size discrepancy, stenosis occurs in the foramen magnum, and interruption of normal cerebrospinal fluid (CSF) flow may lead to hydrocephalus (Figure 4 ) .

 Neuraxial compression is often caused by basilar impression  and intussusception[5] . İf the dens is positioned above the caudal borders ,basilar impression occurs. Basilar invagination is diagnosed when the dens protrudes  superior to McRae’s line [6] . Neuraxial compression can cause serious neurologic damage because of brain stem compression .  Basilar invagination, basilar impression, and platybasia  have been observed in 37% of patients with Osteogenesis Imperfecta ( Figure 5).

 

 

RESULTS or FİNDİNGS:

The risk of craniocervical junction stenosis is increased in genetic disorders (Table 1 )

We describe the craniocervical junction stenosis that we detected in asymptomatic patients who have no trauma history . We present craniocervical junction stenosis cases with Down syndrome (Figure 6), Achondroplasia(Figure 7) and  Osteogenesis Imperfecta(Figure 5 ).

 

 

CONCLUSİON :

Although craniocervical junction stenosis is not always symptomatic, it is important to recognize to prevent further physical and possible neurological damage.