Posterior osteosynthesis with monoaxial lateral mass screw-rod system for unstable c1 burst fractures

Publication date: Available online 21 July 2017
Source:The Spine Journal
Author(s): Yin-shun Zhang, Jian-xiang Zhang, Qing-guo Yang, Wei Li, Hui Tao, Cai-liang Shen
Background ContextSurgical treatment for unstable atlas fractures has evolved in recent decades from C1-C2 or C0-C2 fusion to motion-preservation techniques of open reduction and internal fixation (ORIF). However, regardless of transoral or posterior approach, the reduction is still not satisfactory.PurposeThe article describes and evaluates a new technique for treating the unstable atlas fractures by using a monoaxial screw-rod system.Study DesignThis is a retrospective studyPatient SampleThe sample includes adult patients with unstable C1 fractures treated with a posterior monoaxial screw-rod system.Outcome MeasuresVisual analog pain scale (VAS),radiographic reduction (lateral mass displacement), maintenance of reduction, C1-C2 instability (anterior atlanto-dens interval), and complications.MethodsFrom August 2013 to May 2016, 9 consecutive patients with unstable atlas fractures were retrospectively reviewed. All patients were treated with posterior ORIF by using a monoaxial screw-rod system. The medical records and the preoperative and postoperative radiographs were reviewed. The preoperative and postoperative computed tomography (CT) scans were used to specify the fracture types and to assess the reduction.ResultsAll 9 patients with a mean age of 50.3 years successfully underwent surgery with this technique, and a follow-up of 17.4±9.3 months was performed. Transverse atlantal ligament (TAL) injury was found in 8 of the 9 patients: 1 of type I and 7 of type II. The preoperative lateral mass displacement averaged 7.0±2.2 mm and was restored completely after surgery; all the fractures achieved bony healing without loss of reduction or implant failure. None of the patients had complications of neurological deficit, vertebral artery injury, or wound infection associated with the surgical procedure. Two patients complained of greater occipital nerve neuralgia after the operation, which gradually disappeared in 1 month. All patients had a well-preserved range of motion of the upper cervical spine at the final follow-up.ConclusionsPosterior osteosynthesis with a monoaxial screw-rod system is capable of almost anatomical reduction for the unstable atlas fractures. The TAL incompetence may be not a contraindication to ORIF for C1 fractures, but the long-term effect of C1-C2 instability remains to be further investigated.



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