Successful cranio-cervical fusion in a patient with Down syndrome C.S. Johnson a , D.N. Wilson b,⇑ , R.J. Mobbs a a Prince of Wales Hospital, Barker Street, Randwick, Sydney, New South Wales, Australia b Royal North Shore Hospital, Reserve Road, St Leonards, Sydney, New South Wales, Australia article info Article history: Received 12 September 2011 Accepted 3 March 2012 Keywords: Cranio-cervical fusion Cranio-cervical instability Cranio-vertebral junction Down syndrome abstract We present a patient with Down syndrome with neck pain and severe cervical myelopathy. Imaging revealed occipito-atlantal and atlanto-axial instability with severe spinal cord compression. There are no standardized radiological or clinical guidelines to aid in managing this unique subset of patients. We demonstrate a successful occiput–C3 internal fixation and fusion without complication. Due to the largely unknown natural history and ongoing management difficulties in this population, we demon- strate a case that may aid future decision making for this specialized field. We also discuss an approach to reduce this deformity, which, to our knowledge, has not been published before. Ó 2012 Published by Elsevier Ltd. 1. Introduction Down syndrome is the most common human chromosomal abnormality, and has been associated with myelopathy from cra- niovertebral instability. It is felt that symptomatic patients should be offered surgical stabilization. This report demonstrates a suc- cessful surgical approach in a young female with myelopathy and instability. 2. Case report A 14-year-old female patient with Down syndrome presented with a 2-year history of neck pain; progressive ataxia; limb weak- ness and in coordination. Clinically she had minimal neck rotation, was hyperreflexic with sustained clonus, and had mild limb weak- ness. Lateral cervical radiographs showed occipito-atlantal and atl- anto-axial subluxation. Subsequent investigations confirmed subluxation of C1/2 with an atlanto-dens interval (ADI) of 10 mm and vertical subluxation of the odontoid process, and subluxation of occiput/C1, with foramen magnum and spinal canal narrowing (Fig. 1). MRI confirmed myelomalacia. The patient underwent a 7-hour occiput–C3 internal fixation and fusion. Through a suboccipital approach, internal fixation was achieved with C1 lateral mass, C2 pars and C3 lateral mass screws, including an occipital plate and rod with iliac crest bone graft bilat- erally. Subtraction osteotomy of the C2 pars was performed to re- duce the lateral mass of C1 onto the superior facet of C2 (Fig. 2). An iliac crest bone graft with tricalcium phosphate was used. Immobilization in a Miami-J orthosis for 3 months was used post- operatively. CT scans showed solid fusion at 6 months (Fig. 3). 3. Discussion The etiology of craniovertebral abnormalities is diverse and can be a result of acquired, traumatic or inflammatory causes. It is associated with achondroplasia, mucopolysaccaridosis, and Klippel Feil syndrome 1 Craniovertebral abnormality has been associated with Down syndrome since first described in 1961. 2 The natural history is poorly understood, but the consensus is that the instability is chronic and progressive. 3 The variety of abnormalities includes atlanto-axial subluxation, occipito-atlantal instability and os odontoideum. Neurological sequelae, through sudden or progressive neurological deficit, has raised interest since the special olympics ruling for mandatory cervical spine imaging in Down syndrome athletes participating in ‘‘high risk’’ sporting activities. 4,5 There is no standardized link between radiological instability and patient symptomatology, and longitudinal studies have been unable to predict patient outcomes. 5,6 Studies have shown atlan- to-axial instability (AAI) present in 10% to 30% of this population, yet only 1% to 2% of this population show signs of neurological compromise. 5 Tredwell et al. 7 report occipito-cervical hypermobil- ity in 60% of patients with Down syndrome; however, no patient showed signs of neurological compromise. Early studies into craniovertebral instability assessed AAI, with ligamentous laxity and odontoid process abnormalities. Konttinen 8 showed that patients with anterior atlanto-axial subluxation from transverse ligament rupture displayed mild myelopathy only, whereas alar ligament disruption leads to disruption of C1/2 facet joints and vertical subluxation of the odontoid process causing progressive neurological deficit. Recent studies highlight abnormal bony anatomy in patients with Down syndrome as a factor in progressive myelopathy. Taggard et al., 9 and more recently Matsunaga et al., 10 demon- strated C1 hypoplasia as a factor in progressive cervical myelop- athy in these patients. Furthermore, in this study the difference in ADI was not statistically significant between patients with Down syndrome and controls, whereas hypoplasia of C1 was, suggesting bony abnormalities of the craniovertebral skeleton in patients with Down syndrome are more significant risk fac- tors for progressive neurological deficit than appreciated previously. Studies published on outcomes of stabilization are few and, in earlier years, advocated extreme caution. Doyle et al. 4 reported a 73% complication rate in 15 patients with Down syndrome who underwent posterior cervical fusion for AAI, with 40% requiring reoperation. They achieved fusion in 80%, but only a 20% symptom- atic improvement. These findings were supported by Segal et al., who found a 100% complication rate with surgery. 11 The evolution of cervical instrumentation has improved surgical outcomes and more recent reviews show fusion rates as high as 58% to 95%. 3 In addition, as in our patient, surgical stabilisation was achieved without fixed external immobilisation. Our patient highlights the successful treatment of a young fe- male patient with severe progressive cervical myelopathy due to ⇑ Corresponding author. Postal address: 14 Lawson Street, Bondi Junction, Sydney, New South Wales, 2022, Australia. Fax: +61 2 8382 2531. E-mail addresses: cjoh65796@gmp.usyd.edu.au (C.S. Johnson), davidnwilson@ hotmail.com (D.N. Wilson). Case Reports / Journal of Clinical Neuroscience 20 (2013) 329–330 329