| Part one:A novel anterior-only surgical approach for reduction and fixation of subaxial cervical facet dislocation:technique notes and case series.Objectives: To report a novel anterior-only surgical approach for reduction and fixation in patients with cervical facet dislocation,even for severe vertebral fracture,articular process fracture and delayed surgical management.Methods:Between January 2014 and December 2017,63 patients with cervical facet dislocations were admitted to and treated surgically in the investigator's group(Z.Z.).For these 63 patients(55 males and 8 females),the ages ranged from 21 to 73 years old(average 48.8 ± 12.2);the distribution of spine level was from cervical(C)3/4 to C7/thoracic(T)1(including C3/4=4,C4/5=9,C5/6=26,C6/7=22,C7/T1=2);the etiologic diagnosis included 22 unilateral and 41 bilateral facet dislocations;traumatic disc herniation was found in 18 patients on magnetic resonance imaging(MRI);vertebra fracture was found in 20 patients and articular process fracture was found in 14 patients on computed tomography(CT);the neurologic status comprised 17 patients with American Spinal Injury Association(ASIA)grade A,3 with ASIA B,3 with ASIA C,23 with ASIA D,and 17 with ASIA E.The preoperative time was from 3 to 64 days(average 9.5±8.5 days),and follow-up ranged from 12 to 24 months(average 16.1±4.5 months)after the surgery.After discectomy in all patients,anterior kyphotic paramedian distraction reduction with Caspar pins plus vertebral screw plate fixation were performed.If the reduction failed,anterior facetectomy reduction plus anterior cervical pedicle screw plate fixation were introduced.The parameters were as follows: the success rate of reduction,operation time,intraoperative blood loss,the improvement of ASIA grade and fusion rate.Results:Among the 63 patients treated.52 patients(82.5%)achieved successful reduction with the technique of kyphotic paramedian distraction with Caspar pins,including 22 cases of unilateral facet dislocation,30 cases of bilateral facet dislocation,15 cases with vertebra fracture and 7 cases with articular process fracture.The preoperative time was less than 2 weeks in 46 cases and 2-4 weeks in 6 cases.The mean operative time was 76.2±21.9 minutes and the mean blood loss was 66.3±37.0 ml.The other 11 patients with failed reduction were bilateral facet dislocation,including 2 cases with C7/T1 facet dislocation,5 cases with severe vertebral fracture,and 7 cases with articular process fracture.The preoperative time was 16.5±16.4 days(including 2 to 4 weeks in 3 cases and more than 4 weeks in 1 case),which needed to be assisted with anterior facetectomy,and all of them were successfully reduced.At the last follow-up,20(38.5%)of 52 patients with successful reduction by anterior kyphotic paramedian distraction technique increased the ASIA grade by at least one grade(These included 3 cases with preoperative grade A raised to grade B in 2 cases and grade C in 1 case,3 cases from grade C to grade D,and 14 cases from grade D to grade E),and none of the patients had grade decline.Three of the 11 patients with successful reduction by anterior facetectomy technique increased the ASIA grade by one grade(These included 1 case from grade A to grade B,1 case from grade B to grade C,and 1 case from grade D to grade E).all patients achieved satisfactory fusion,and there was no implant failure.Conclusions:1.Anterior kyphotic paramedian distraction technique for reduction of subaxial cervical facet dislocation has the advantages of high success rate,simple operation,small trauma,safe and effective clinical result.2.Anterior-only surgical procedure including kyphotic paramedian distraction with Caspar pins,anterior facetectomy and anterior pedicle screw plate fixation techniques is safe and effective for subaxial cervical facet dislocations.This technique is especially useful for severe vertebral fracture,articular process fracture or delayed surgical management to avoid a posterior procedure.Part two : Comparison of a novel anterior-only approach and conventional posterior-anterior approach for cervical facet dislocationObjectives: compared the surgical trauma and clinical results of a novel anterior-only approach and with those of the conventional posterior-anterior approach to obtain an optimal method to treat the subaxial cervical facet dislocation.Methods:From January 2012 to December 2017,93 patients with subaxial cervical facet dislocations were enrolled in the study.There were 80 males and 13 females,with an average age of 48.2 ± 11.9 years(ranging from 21 to 73 years).The causes of injury included: motor vehicle accident for 24 cases,falling for 28 cases,and other causes for 41 cases.The distribution of injury segments was: C3-C4 in 6 cases,C4-C5 in 13 cases,C5-C6 in 33 cases,C6-C7 in 33 cases,and C7-T1 in 8 cases.Dislocation types included: unilateral facet dislocation in 34 cases and bilateral facet dislocation in 59 cases.The spinal cord injury(ASIA)grades at admission were: ASIA A in 29 cases,ASIA B in 3 cases,ASIA C in 6 cases,ASIA D in 36 cases,ASIA E in 19 cases.The follow-up ranged from 12 to 24 months(average 15.9±4.8 months)after the surgery.According to the surgical approach,they were divided into two groups as: 63 cases in the anterior-only approach group and 30 cases in the posterior-anterior approach group.For anterior-only approach group,two reduction techniques including kyphotic paramedian distraction with Caspar pins and anterior facetectomy were used in sequence if the former was failed.The parameters were compared as follow: the operation time,intraoperative blood loss,the number of fixed segment,the fusion rate,and the improvement of ASIA grade and JOA score.Results:All the patients(63 cases in the anterior-only approach group and 30 cases in the posterior-anterior approach group)underwent the operation successfully.The success rate of reduction was 100%.In the anterior-only approach group,52 cases were directly reduced by anterior kyphotic paramedian distraction technique,and the other 11 patients with failed reduction were successfully reduced by the anterior facetectomy technique.There was no significant difference in age,sex,causes of injury,distribution of injure segments,dislocation types,initial ASIA grade and JOA score between the two groups.The mean operation time in the posterior-anterior approach group(274.0 ± 114.7 minutes)was significantly longer than that in the anterior-only approach group(88.6 ± 35.0 minutes)(p = 0.000).The mean blood loss during the surgery and the number of fixed segments in the posterior-anterior approach group(275.0 ± 183.2 ml;1.4 ± 0.7,respectively)were significantly greater than those in the anterior-only approach group(92.5 ± 84.0 ml,p = 0.000;1.2±0.5,p = 0.030,respectively).A 100% fusion rate was observed in both groups after 12 months follow-up.There were no significant differences between the two groups regarding the improvement in the ASIA grade(p=0.900)or JOA score(p=0.717).Conclusions:Compared with the conventional posterior-anterior approach,the novel anterior-only approach with two reduction techniques,including kyphotic paramedian distraction with Caspar pins and anterior facetectomy,achieved a 100% reduction success rate and induced less surgical trauma,indicating that this method can be recommended as an alternative for subaxial cervical facet dislocation. |
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