Comparison Of Two Different Fusion Methods In The Treatment Of Adjacent Segment Disease After Anterior Cervical Discectomy And Fusion

Background and objectiveAnterior cervical discectomy and fusion(ACDF)is one of the most widely used and mature operations,which was first proposed by Robinson and Smith,and is one of the most commonly used procedures for the treatment of cervical diseases.Since it has immediate stability,high fusion rate,restore normal physiological curvature,spinal cord and nerve root decompression thoroughly and can maintain or even to rebuild the cervical stability,at the same time,the learning curve is short,easy to grasp,it has been widely used in cervical spine diseases such as trauma,disc herniation,spinal diseases and tumors since its introduction in the 1950s,and is the preferred treatment for cervical degenerative diseases by the majority of orthopedic surgeons.However,the biggest disadvantage of ACDF is that it changes the biomechanical properties of the cervical spine.Clinical and biomechanical studies have shown that increased mobility,intervertebral disc pressure,and stress in adjacent segments after ACDF surgery may accelerate the Adjacent segment degeneration(ASD).ASD is a relatively common degenerative condition that occurs above or below the fusion level after cervical spine surgery.Clinical symptoms are caused by compression of nerve roots and spinal cord.Compressive agents may include disc herniation,hyperosteogeny,and ligamentous thickening.With the in-depth study of large-scale clinical cases and the continuous extension of follow-up time,reports on the postoperative ASD of ACDF,are also increasing year by year,which affects the long-term effect of surgery.Moreover,the occurrence of ASD is one of the important reasons for re-hospitalization of patients after ACDF surgery.Data from clinical studies confirm that most ASD patients receive only conservative treatment.Therefore,ASD patients with failure of conservative treatment or progression of disease and consistent clinical symptoms and signs with imaging evidence should receive re-surgical treatment.However,there are many treatment methods for adjacent segment disease,including re-ACDF,zero-profile interbody fusion and fixation(zero-P),anterior cervical corpectomy fusion(ACCF),simple Cage implantation and total disc replacement(TDR).However,there is no unified standard surgical method at present.Zero-profile fusion and titanium plate combined with cage fusion are the two most widely used revision strategies in clinical practice at present,but there is a lack of a large number of data to support their clinical efficacy.The purpose of this study was to analyze the imaging and clinical efficacy of zero-profile interbody fusion and titanium plate combined with cage fusion in the treatment of symptomatic ASD.Therefore,there are three purposes of this study:①To investigate the general clinical features of ASD after ACDF surgery;②To investigate the imaging and clinical efficacy of zero-profile interbody fusion and conventional titanium plate combined with Cage fusion for symptomatic ASD after ACDF surgery;③ To investigate the advantages of zero-profile interbody fusion and fixation in the treatment of symptomatic ASD after ACDF.MethodsRetrospective analysis was performed on 26 patients who underwent ACDF and readmission due to concurrent symptomatic ASD from October 2014 to June 2019.included 17 males and 9 females,aged 54.15±8.60(range 41～68)years.The index level included C2/3 1 case,C3/4 3 cases,C4/5 9 cases,C5/6 6 cases,C6/7 7 cases.Among them,12 cases underwent anterior cervical decompression with zero-p intervertebral fusion and fixation(zero-p group),included 8 males and 4 females,aged 52.33±8.41 years;and 14 cases underwent anterior cervical decompression with titanium plate combined with cage fusion and fixation(titanium plate group),included 9 males and 5 females,aged 55.71±8.75 years.Gender,age,operative time,intraoperative blood loss,Preoperative,postoperative and final follow-up Japanese Orthopaedic Association(JOA)score,visual analogue scale(VAS),neck disability index(NDI),dysphagia Bazaz grade,bone graft fusion Eck grade,C2-C7 Cobb angle,and related complications were compared between the two groups.ResultsThe operation was performed successfully in all the patients.All the 26 patients were followed up for more than 12 months.The patients were followed up for averagely 33.38±21.26(range 12-71)months.There was no significant difference in gender and age between the two groups(P<0.05).The operation duration was 95.83±5.47(range 89-105)min in the Zero-p group,which was shorter than 121.28±8.24(range 106-131)min in the titanium plate group.The Bazaz classification of dysphagia in the Zero-p group was superior to the titanium plate group at 1 month after operation(W=126.00,P=0.022).There was no statistically significant difference between the two groups in the bone graft fusion Eck grade at the last follow-up(W=179.00,P=0.504).The JOA scores,VAS score,NDI,C2-C7 Cobb Angle of the zero-p group and the titanium plate group at 3 months after surgery and the last follow-up were significantly different from those before surgery(P<0.05).However,there was no statistically significant difference between the two groups(P>0.05).During the follow-up period,all the patients did not have a rupture of the settler screw and esophageal injury and other related diseases.Neither group had dysphagia 3 months after surgery.Conclusions1.ASD after ACDF is more common at the upper level of the fused segment,and C4/5,C5/6 and C6/7 levels are associated with a higher risk of developing symptomatic ASD than at other segments2.Both anterior cervical decompression and zero-profile intervertebral fusion and titanium plate combined with Cage fusion and internal fixation can effectively effectively restore and maintain the physiological curvature of cervical vertebra to a certain extent,and relieve spinal cord and nerve compression in the treatment of symptomatic ASD,and achieve satisfactory clinical results.3.Compared with the traditional ACDF fused with titanium plate and cage,the ACDF fused with zero profile can significantly shorten the operation time and reduce soft tissue injury in the treatment of symptomatic ASD,and further reduce the occurrence of early postoperative dysphagia.