Posterior atlas limited internal fixation for atlas unstable fractures

English Keywords:Atlas fractures  Internal fixation  Outcome

English Abstract:

  【Abstract】 Objectives: To investigate the surgical outcomes of posterior C1 screw-rod system for C1 unstable fractures． Methods: From April 2008 to October 2010, 10 patients with C1 unstable fractures underwent posterior C1 screw-rod system. There were 7 males and 3 females with the average age of 37.5 years(range, 20-60 years). All patients complained of neck pain, stiffness, and decreased range of motion without neurologic deficit． Six patients had bilateral posterior arch fractures associated with unilateral anterior arch fractures(posterior 3/4 Jefferson fracture, Landells type Ⅱ), and four had unilateral anterior and posterior arch fractures(half-ring Jefferson fracture, Landells type Ⅱ). Seven patients had intact transverse ligament, and three patients had fractures and avulsion of the attachment of transverse ligament(Dickman type Ⅱ)． Preoperative skull traction was used routinely. Results: A total of 20 screws were inserted safely. 3 cases had pedicle screw placed in lateral mass due to posterior arch breakage in 1 case, entry point breakage in 1 case , and the height of posterior arch at the entry point less than 4mm in 1 case. The remaining 7 cases had screw placed in pedicle. The operative time was 60-90min, with a mean of 70.5min, and the intraoperative blood loss ranged from 100-300ml, with a mean of 150ml. 1 case was complicated with veiniplex injury with no heavy blood loss due to successful hemostasia． No spinal cord or vertebral artery injury during surgery was noted. Postoperative roentgenograph and CT scan showed transverse foramen penetration in 1 case, and breakage of medial wall of spinal canal in 1 case, but no neurovascular injury was noted．The remaining screws were in good position. All patients were followed up for 12-36 months, with a mean of 20.2 months． All cases were completely painfree and had full range of motion of the cervical spine 3-6 months later after surgery. Bony fusion was achieved 6 months later. During the follow-up period, good cervical alignment was maintained with no instrument failure and C1-2 recurrent instability. Conclusions： In the premise of strictly select surgical indications, posterior C1 screw-rod fixation system is a better way for treatment of C1 unstable fractures, which can preserve the function of the craniocervical junction.