Craniovertebral Abnormalities in Down’s Syndrome

Abstract

The ligamentous laxity associated with atlantoaxial subluxation has been assumed as a normal occurrence in 15–20% of Down’s syndrome patients. The occipitoatlantoaxial instability that accompanies this entity has been poorly recognized. The medical records and radiographic findings of 18 symptomatic patients with Down’s syndrome and cervicomedullary compromise were reviewed (1979–1991). All patients were evaluated prospectively under protocol for abnormalities of the cranial vertebral junction. There were 11 males and 7 females (age 3–42). ‘Fixed’ atlantoaxial luxation was seen in 8 (5 developed precipitous onset of cervical medullary compression). Occipitoatlantoaxial instability was present in 9 and associated rotary luxation in 9. The average predental space was 8 mm in the neutral position in 18 individuals. Two adolescents had previously undergone atlantoaxial dorsal fusion with subsequent progressive basilar invagination due to unrecognized occipitoat-lantal instability. An os odontoideum was seen in 3 patients. Irreducible invagination in 2 was treated with anterior decompression followed by dorsal occipital cervical fixation. The occipital cervical fixation was utilized in 10 individuals. Atlantoaxial dorsal fusion was made in 7 and 2 patients with acute rotary luxation of C1 and C2 were treated with immobilization. Halo immobilization in two individuals following a dorsal occipital cervical fixation produced an anterior fusion at the cranial vertebral complex indicating active vertebral ligamentous pathology. The review focuses on increased incidence of occiput cervical instability in the spectrum of craniovertebral junction abnormalities associated with Down’s syndrome. A large percentage has an odontoid ossicle probably as a result of repeated minor trauma. The results of surgical stabilization have been shown to be excellent.

Pediatric Occipitocervical Arthrodesis

“…Most techniques have been developed and discussed for the adult population [1, 13, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28]. In general, methods for posterior occipitocervical arthrodesis in adults can be categorized into (1) onlay grafts, with [19, 20, 21, 22, 23, 28, 29, 30, 31]or without [13, 17, 18]wiring, and (2) rigid internal fixation using methylmethacrylate [12, 32, 33], plates and screws [9, 11, 24, 34, 35], and malleable rods with segmental wire fixation [18, 27, 36, 37, 38, 39, 40, 41].…”

“…An anterior occipitocervical fusion technique in a 13-year-old using a free osteocutaneous flap has recently been reported by Smith et al [47]. Some investigators have included an occasional adolescent in an evaluation of a rigid internal fixation device [1, 24, 37, 40], and reports of occipitocervical arthrodesis obtained through nonspecific techniques for traumatic [4]and nontraumatic [2]atlanto-occipital disorders in the pediatric age group exist. However, to our knowledge, only 4 published reports (totaling 24 subjects) have evaluated rigid internal fixation techniques for occipitocervical arthrodesis exclusively in children [43, 44, 45, 46].…”

“…Nevertheless, disruption of the normal bony and ligamentous complex comprising the craniocervical junction can occur traumatically, with inflammatory processes, and iatrogenically, as with skull base tumor resections or ventral craniocervical decompression for spinal anomalies. Additionally, various congenital diseases such as the mucopolysaccharidoses, spondyloepiphyseal dysplasia, Down’s syndrome and Klippel-Feil deformities may all predispose children to craniocervical instability [1, 2, 3, 4, 5]. …”

Superior odontoid migration in the Klippel–Feil patient

“…Excessive SOM could increase the threat of neurologic compromise and potentially death [11,12,30,39,50]. SOM has been associated with various disorders, such as rheumatoid arthritis [13,17,35,42,48], Down's syndrome [34,52], osteogenesis imperfecta [30,47], and Klippel-Feil syndrome (KFS) [1,10,18].…”

Occiput-cervical fusion for symptomatic atlantoaxial subluxation in a 32-month-old child with Down syndrome: a case report

“…3 Both patients made a good neurological recovery. Similarly, a 48-month-old girl was treated with posterior arthrodesis and postoperative halo immobilization.…”