The state of the sagittal balance of the injured cervical spine depending on the nature of the damage to the subaxial level

Abstract

Background. Three main interrelated principles form the basis for modern surgery of traumatic cervical spine injuries, namely decompression, reconstruction and stabilization. Restoration of the sagittal profile is one of the basic tasks of the reconstructive stage. Currently, there are no clear recommendations for surgical management in traumatic injuries depending on the degree of deformation, and the state of sagittal balance of the injured cervical spine in the preoperative period has practically not been studied. The purpose of the work is to study the state of the sagittal profile and the degree of segmental deformation of the cervical spine following traumatic injury at the subaxial level, to determine the relationship between them and the type of injury. Materials and methods. We performed a retrospective analysis of X-ray data from 140 patients with subaxial cervical spine traumatic injury who were hospitalized at the Department of Spinal Cord Pathology of the Romodanov Neurosurgery Institute of the National Academy of Medical Sciences of Ukraine in the period from 2008 to 2018. We calculated indicators of segmental kyphosis and general cervical lordosis and determined the type of damage according to AO Spine Subaxial Cervical Spine Injury Classification System. Results. We found that the type of the damage affects the degree of segmental deformation (p < 0.001). Type A1, A2 and C injuries show the maximum kyphotic angulation: 13.51° (8.18; 20.07), 21.8° (20.12; 22.96) and 20.01° (17.52; 21.99), respectively. Injuries of type A2 and C statistically significantly differ from other types of lesions. We registered maximum values of deviations from the normal sagittal circuit in patients with injuries types A2 and C: ‒26.77° (‒32.78; ‒20.91) and ‒26.70° (‒36.30; ‒16.77), respectively. The parameters of segmental kyphosis and general cervical lordosis reveal high interdependence (r2=0.766, p < 0.001). We found maximum correlation in type A3, A4 and B3 injuries: ‒0.93, ‒0.91 and ‒0.97, respectively (p < 0.001). And types A1 and A2 injuries demonstrated statistically insignificant relationship (p > 0.05). Conclusions. The results show that traumatic injury of the subaxial cervical spine is characterized by a wide range of kyphotic segmental angulation values, which is largely determined by the type of injury. General cervical lordosis tends to flatten in most cases, but the degree of physiological curvature loss correlates with local deformation to some extent.