Larsen's syndrome is a rare inherited defect of connective tissue that is transmitted in both an autosomal dominant and recessive pattern. First described by Larsen [1], its cardinal findings consist of multiple congenital joint dislocations, usually of the hips, knees and elbows. Facially, there is frontal bossing, a depressed nasal bridge, hypertelorism and a flat facies. Deformities of the fingers (spatulate) and calcaneus (a double ossification centre), and spinal anomalies that may lead to major spinal instability and spinal cord injury, are important characteristics. Although abnormalities of the cervical spine were not emphasized in the original description of the syndrome [1], they may lead to serious complications.
Of the 9 affected infants followed by Johnston et al. [9], 5 were noted to have cervical kyphosis because of marked hypoplasia of 1 or 2 vertebral bodies (usually the fourth or fifth cervical vertebra, or both) at the apex of the kyphosis; the infants were successfully managed by posterior cervical arthrodesis alone. Johnston et al. [9], suggested that the prevalence of cervical kyphosis in Larsen syndrome has probably been underestimated, but may easily be documented because no dynamic studies or cooperation by the patients are necessary.
Laville et al. [2], reviewed thirty-eight patients with Larsen syndrome who came from an isolated geographical area and did not find any who had cervical kyphosis. In that series, however, the absence of the accessory calcaneal apophysis, which is a characteristic radiographic finding in classic Larsen syndrome, casts doubt on the diagnosis and, hence, on the validity of the failure to observe cervical deformity. It might however just have been underdiagnosed. The potential morbidity and mortality from this deformity are obvious. Indeed, one of the patients of Micheli et al. [7], died at the age of twenty-six months as a result of compression of the spinal cord, before the deformity of the neck could be treated. Also, one of the original patients of Larsen et al, [1, 2] died at the age of one year after open reduction of a dislocation of the knee. The death was attributed to so-called respiratory anaesthetic complications.
Diverse treatment options in patients with Larsen syndrome, including conservative observation and surgical correction, have been reported for patients who present with cervical spine pathophysiology. Differences in surgical approaches, timing of the correction, and pre- or postoperative bracing have been reported [10]-[12].
Lachman [13] described the poor ossification and or developmental failure of the cervical vertebrae has been described exclusively in patients with skeletal dysplasias. Lethal and non-lethal types have been described such as, campomelic dysplasia, diastrophic dysplasia, chondrodysplasia punctata, opsismodysplasia, Desbuquois dysplasia, achondrogenesis type IA and IB and achondrogenesis type II and others.