The change of anterior atlanto-dense interval in atlantoaxial instability patients: preoperative vs postoperative

ABSTRACT

BACKGROUND: Atlantoaxial subluxation (AAS) is a frequent manifestation of rheumatoid arthritis (RA). The instability of the cervical spine caused by AAS is potentially fatal condition under intubation for surgery. Anterior atlanto-dens interval (AADI) is a mirror of the risk for neural injury. We evaluated the change of AADI in atlantoaxial instability patients, before and after surgery. METHODS: The present study included 56 patients who underwent surgical procedures by AAS. Lateral radiographs were checked at preoperative, postoperative, 1 month later and 6 month later. AADI was measured using picture archiving communication system (PACS) system in each lateral radiograph. RESULTS: The value of AADI is 8.40 +/- 2.29 mm in preoperative period, 2.72 +/- 0.53 mm in postoperative, 2.68 +/- 0.53 mm in 1 month, and 2.70 +/- 0.51 mm in 6 months later. After cervical fusion, AADI immediately decreased 5.68 +/- 2.24 mm. There were significant decreased in postoperative, 1 month and 6 months, when compared with preoperative AADI. CONCLUSIONS: After the cervical fusion of AAS, the neurological and radiological stability was achieved by decrement of AADI. We concluded that the cervical fusion of AAS provide more safety during endotracheal intubation by decreased AADI.