Classified reduction based on CT two-dimensional images for the surgical treatment of single segment facet joint dislocation in subaxial cervical spine / 中华创伤杂志

ABSTRACT

Objective:To investigate the efficacy of the classified reduction based on CT two-dimensional images for the surgical treatment of single segment facet joint dislocation in subaxial cervical spine.Methods:A retrospective case series study was made on 105 patients with single segment facet joint dislocation in subaxial cervical spine admitted to Zhengzhou Orthopedic Hospital from January 2015 to October 2022. There were 63 males and 42 females, with the age range of 22-78 years [(47.5±3.6)years]. Preoperative American Spinal Cord Injury Association (ASIA) classification was grade A in 23 patients, grade B in 45, grade C in 22, grade D in 15 and grade E in 0. The classification of surgical approach was based on the presence or not of continuity between anterior and posterior subaxial cervical structures and the movability of the posterior cervical facet joint on CT two-dimensional images, including anterior cervical surgery if both were presented and posterior facet joint resection plus anterior cervical surgery if there was discontinuity between anterior and posterior subaxial cervical structures or posterior facet joint fusion. Reduction procedures were applied in accordance with the type of facet joint dislocation classified based on the position of the lower upper corner of facet joint, including skull traction or manipulative reduction for the dislocation locating at the dorsal side (type A), intraoperative skull traction and leverage technique for the dislocation locating at the top (type B) and intraoperative skull traction and leverage technique with boosting for the dislocation locating at the ventral side (type C). If the dislocation of two facet joints in the same patient was different, the priority of management followed the order of type C, type B and type A. The reduction success rate, operation time and intraoperative blood loss were recorded. The cervical physiological curvature was evaluated by comparing the intervertebral space height and Cobb angle before operation, at 3 months after operation and at the last follow-up. The fusion rate of intervertebral bone grafting was evaluated by Lenke grading at 3 months after operation. The spinal cord nerve injury was assessed with ASIA classification before operation and at 3 months after operation. Japanese Orthopedic Association (JOA) score was applied to measure the degree of cervical spinal cord dysfunction before operation and at 3 months after operation, and the final follow-up score was used to calculate the rate of spinal cord functional recovery. The occurrence of complications was observed.Results:All patients were followed up for 3-9 months [(6.0±2.5)months]. The reduction success rate was 100%. The operation time was 40-95 minutes [(58.6±9.3)minutes]. The intraoperative blood loss was 40 to 120 ml [(55.7±6.8)ml]. The intervertebral space height was (4.7±0.3)mm and (4.7±0.2)mm at 3 months after operation and at the last follow-up, significantly decreased from preoperative (3.1±0.5)mm (all P<0.01), but there was no significant difference in intervertebral space height at 3 months after operation and at the last follow-up ( P>0.05). The Cobb angle was (6.5±1.3)° and (6.3±1.2)° at 3 months after operation and at the last follow-up, significantly increased from preoperative (-5.4±2.2)° (all P<0.01), but there was no significant difference in Cobb angle at 3 months after operation and at the last follow-up ( P>0.05). The fusion rate of intervertebral bone grafting evaluated by Lenke grading was 100% at 3 months after operation. The ASIA grading was grade A in 15 patients, grade B in 42, grade C in 29, grade D in 12 and grade E in 7 at 3 months after operation. The patients showed varying degrees of improvement in postoperative ASIA grade except that 15 patients with preoperative ASIA grade A had partial recovery of limb sensation but no improvement in ASIA grade. The JOA score was (13.3±0.6)points and (13.1±0.6)points at 3 months after operation and at the last follow-up, significantly improved from preoperative (6.8±1.4)points (all P<0.01), but there was no significant difference in JOA score at 3 months after operation and at the last follow-up ( P>0.05). The rate of spinal cord functional recovery was (66.3±2.5)% at the last follow-up. All patients had no complications such as increased nerve damage or vascular damage. Conclusion:The classified reduction based on CT two-dimensional images for the surgical treatment of single segment facet joint dislocation in subaxial cervical spine has advantages of reduced facet joint dislocation, recovered intervertebral space height and physiological curvature, good intervertebral fusion and improved spinal cord function.