Spinal fractures in patients with ankylosing spondylitis.
Thirty-one consecutive patients with ankylosing spondylitis and spinal fractures were reviewed. There were 6 women and 25 men with a mean age of 60 +/- 11 years; 19 had cervical and 12 had thoracolumbar injuries. Of the patients with cervical fracture, two had an additional cervical fracture and one had an additional thoracic fracture. Three trauma mechanisms were identified: high-energy trauma in 13 patients, low-energy trauma in 13 and insufficiency fracture in 5. One-third of the patients suffered immediate neurological impairment, a further one-third developed neurological impairment before coming for treatment and only one-third remained intact. Two patients with thoracolumbar fractures had deteriorated neurologically due to displacements during surgery at other hospitals. All patients were treated operatively except the two patients with two-level cervical fractures, who were managed in halo vests. In the cervical spine both anterior and posterior approaches were employed. In the thoracolumbar spine the majority of the patients were initially treated using a posterior approach only. Complications were common. Of the 27 patients with neurological compromise, 10 had remained unchanged; 12 had improved one Frankel grade; 4 had improved by two Frankel grades; 1 had improved by four Frankel grades. We conclude that even minor trauma can cause fracture in an ankylosed spine. A high proportion of patients with spinal fractures and ankylosing spondylitis have neurological damage. The risk of late neurological deterioration is substantial. As the condition is very rare and the treatment is demanding and associated with a very high risk of complications, the treatment of these patients should be centralised in special spinal trauma units. A combined approach that stabilises the spine from both sides is probably beneficial.