Guidance value of TOI classification for treatment of traumatic T-type atlantoaxial dislocation

Abstract

Objective To investigate the guidance value of TOI classification in treating traumatic T-type atlantoaxial dislocation (ADD). Methods A retrospective case series study was made on 32 cases of traumatic TOI T-type ADD treated between January 2012 and December 2015. There were 19 males and 13 females, aged (38.4±14.7)years. Fifteen cases of T1-type underwent external fixation or internal fixation without fusion, while 17 cases of T2-type underwent internal fixation with fusion. Symon-Lavender clinical standard, Japanese orthopedic association score (JOA), visual analogue scale (VAS), atlas-dens interval (ADI) and space available for the cord (SAC) were used to evaluate the therapeutic effect. Results Patients were followed up for 6-54 months (mean, 32.4 months). At final follow-up, ADI was decreased to (2.3±1.4)mm from preoperative (5.6±1.6)mm, but SAC was increased to (15.4±1.9)mm from preoperative (12.0±2.9)mm (P<0.01). At final follow-up, cervical axial rotation range of motion was 102°-154° in T1-type cases and 57°- 93° in T2-type cases. Range of motion for atlantoaxial joint was preserved in T1-type cases, but lost in T2-type cases. According to the Symon-Lavender clinical standard, there were 14 cases of mild disability, nine moderate disability, eight severe disability and one extremely severe disability before operation; there were 21 cases of mild disability, nine moderate disability and two severe disability at last follow-up. Significant difference was observed in the grades according to the Symon-Lavender clinical standard before operation and at last follow-up (P<0.05). At last follow-up, JOA score was increased to (14.6±2.9)points from preoperative (9.9±3.2)points, and VAS was decreased to (2.7±1.3)points from preoperative (6.0±1.6)points (P<0.01). Conclusions By using TOI classification, reconstruction of stability and improved neurological function can be achieved in treatment of traumatic T-type atlantoaxial dislocation. Non-fusion treatment of T1-type atlantoaxial dislocation can preserve range of motion for atlantoaxial joint. Key words: Atlanto-axial joint; Dislocations; Classification