Study Of An Improvement Of Hangman's Fracture Classification And Its Clinical Preliminary Application

Objective Through assessing C2/3 intervertebral disc injury after the Hangman's fractures by using MRI (analyzing the morphological and signal changes of C2/3 intervertebral organizations), we proposed a clinical improvement classification of Hangman's fracture, and probed the significance of guidance of the modified classificantion in the clincal treatment of Hangman's fractures.Methods 45 cases of Hangman's fractures were collected during 7 years(from April,2004 to April,2010). firstly,according to Levine-Edwards classification,we have determined the type of each case;combining the classification of Levine-Edwards with the morphological changes on MRI imaging of each case after injury,the classification of form was drawn up simply;secondly,according to singnal changes of the MRI T2 films of interverbral tissues injury,the degree of damages were definited.Finaly,we analyzed the relationships each other: the proposed classification , the Levine-Edwards'classification, the classification of forms on MRI imaging performance and the grades of the intervertebral tissues injury.Study of clinical application:according to the difference of the MRI T₂ singnal changes of intervertebral tissues injury,we randomly selected 22 cases to treat follow the guide of the classification of Levine-Edwards and definited group A: type-â… with conservative treatmeant,type-â…¡,â…¡a andâ…¢with surgical treatment,and type-â…¡and type-â…¡a maily taked by posterior approach, type-â…¢mainly taked by anterior approach[1-2];while the other 23 cases were treatde follow the guide of the improved classification and definited group B: type- A with conservative treatment, type- B taked by anterior or posterior surgery,and type- C ( containing two subtypes type- C₁ and type-C₂ ) taked by anterior surgery. Each case after treatment was followed 12 to 48 months (means 25±2 months). To compare the execellent rate of clinical treatment under the guidance of the improved classification with the excellent rate of clinical treatment under the guidance of the Levine-Edwards'classification, the therapeutic effects were studyed according to the Rasmussen assessment criteria.Physical symptoms of the patient,fracture healing and spinal stability were all concerned. And analysed the correlation between the injury extent of intervertebral tissues with the excellent rate of the clinical treatment.We applied the SPSS 13.0 software to deal with the conversion data.Statistical significance was accepted at the P<0.05 level.Results1. Through analysing the clinical manifestations and the characteristics of distribution of the morphology and signal changes of the MRI films,we has proposed the improved classification of Hangman's fracture based on the Levine-Edwards'classification:Type-A—simple vertebral arch fracture:no displacement and angulation between C2 with C3 , C2/3 intervertebral space , anterior and (or) posterior longitudinal ligament was no significant morphological changes, and MRI T₂ images without singnal changes . comparing with adjacent segment disc ,signal was no significant difference.Type- B—vertebral arch fracture with intervertebral disc injury:C2/3 interverteb- ral tissues no significant shift or the height out of proportion of the 1/3 posterior intervertebral disc ,but with disc injury,the MRI T₂ images often has spots or flakes high signal change(disc high signal zone is often less than disc radiu),and sometimes the posterior longitudinal ligmant was fractured.Type- C—vertebral arch fracture with intervertebral disc injury and displacement (including two subtype : type-C₁ ,type- C₂ ):Type- C₁—the height out of proportion of the 1/3 posteroir intervertebral disc or all disc height decreased, and parts of the intervertebral disc with more serious injury moved to beyond the front of C3 vertebral body,there has flake high signal change on MRI T₂ image (disc high signal zone is often greater than disc radiu),and sometimes there is anterior and (or) posterior longitudinal ligament rupture shadow. Type-C2—intervertebral disc height completely loss and completely dislocate, with severe injury of intervertebral disc; MRI T2 image often has coherent high signal change, anterior and posterior longitudinal ligment often ruptured.2.the effects of clinical treatment of 22 patients by the guidance of the Levine-Edwards'classification (execellent rate of clinical treatment ) is 64%:clinical efficacy of various types : type-â… 50%,type-â…¡70% , type-â…¡_a 60% and type-â…¢100%.3.The effects of clinical treatment of 23 patients by the guidance of the improved classification ( execellent rate of clinical treatment ) is 100%: clinical efficacy of various types: type- A 100%, type- B 100%, type - C 100%..4.The correlation between the degrees of intervertebral tissues injuryed and the excellent rate of the clinical treatment:r=0.562 ,p=0.003. the degrees of C2/3 intervertebral tissues injury and the excellent rate of the clinical treatment exists correlations.Conclusion1.The signal and morphological changes of the C2/3 intervertertebral disc and anterior and ( or) posterior longitudinal ligment of Hangman'fracture on MRI can be objective to understand the degrees of the intervertebral tissues injury,and has proposed the improvement of Hangman's fracture classification:type-A—simple vertebral arch fracture; type- B—vertebral arch fracture with intervertebral disc injury in situ; type-C—vertebral arch fracture with intervertebral disc injury and displacement (including two subtypes: type-C₁ ,type-C₂):2. The improved classification has some significance in the guidance of clinical treatment of Hangman's fracture .According to the new classification of Hangman's fracture,the treatment can achieve satisfactory clinical efficacy by different way,and suggests it greatly consider the severity of soft tissue injury and take a postive surgical measure to intervene that.