“膜-壁分离”现象对颈椎前路植骨融合内固定术治疗平山病疗效的影响

The impact of the loss of attachment in Hirayama disease patients treated with anterior cervical discectomy and fusion

目的探讨平山病患者颈椎屈曲位MRI特异性“膜-壁分离”现象(loss of attachment)对颈椎前路融合内固定术后疗效的影响。方法2014年2月至2016年11月共纳入接受双节段颈椎前路融合内固定术治疗的平山病患者26例。术前均行颈椎中立位及屈曲位MR检查,术后3个月复查颈椎屈曲位MRI。“膜-壁分离”现象测量包括横向分离程度与纵向分离范围,横向分离程度选择颈椎屈曲位MRI上颈脊髓前移最明显节段的横断面进行测量,参数包括颈脊髓后缘至椎管后壁距离(x)、椎管前-后壁间距离(y)、颈脊髓前后径(a)、颈脊髓横径(b),根据上述参数计算颈脊髓变细程度(中立位a/b),颈脊髓变形程度(屈曲位a/b),以及颈脊髓前移程度(屈曲位x/y-中立位x/y);纵向分离范围在颈椎屈曲位MRI矢状面测量“膜-壁分离”现象涉及颈胸椎活动节段数。所有患者在术前及术后1年评估双手握力及上肢功能障碍评定量表(disabilities of arm,shoulder and hand,DASH)评分。根据DASH评分结果将患者分为术后改善组(术后DASH评分减少)和术后无改善组(术后DASH评分不变或增加)。采用Logistic回归及ROC曲线分析平山病患者颈椎前路融合内固定术后疗效的影像学影响因素。结果平山病患者术后颈椎屈曲位x/y明显减小(t=10.25,P=0.001)、颈椎屈曲位a/b则明显增大(t=4.27,P=0.001)。术后23例(88.5%)患者“膜-壁分离”现象完全消失,重侧握力(P=0.36),轻侧握力(P=0.42)及与DASH评分(P=0.06)较术前均无明显改变。“膜-壁分离”纵向累及范围(t=-5.56,P=0.001)、颈脊髓变形程度(t=3.06,P=0.005)及颈脊髓前移程度(t=-3.76,P=0.001)在术后改善组(17例,65.4%)与术后无改善组(9例,34.6%)的差异有统计学意义。以上述3个参数为自变量进行Logistics回归分析,结果显示“膜-壁分离”现象纵向累及范围(OR=6.963)为平山病患者术后疗效的影响因素(P=0.001),以其为研究对象绘制ROC曲线,AUC为0.902,约登指数为0.83,临界值为4.5。结论颈椎前路融合内固定术能有效地改善平山病患者异常的“膜-壁分离”现象,阻止上肢运动功能障碍的持续进展。“膜-壁分离”现象是颈椎前路融合内固定术后疗效的影响因素,且当纵向分离范围≥5个颈椎活动节段时,可能需要更长节段的融合,来进一步改善此类患者的手术疗效。

Objective To investigate the impact of the loss of attachment on the outcomes in Hirayama disease(HD)patients treated with anterior cervical discectomy and fusion(ACDF).Methods A total of 26 patients(23 males and 3 females)who were diagnosed as HD and received 2 levels of ACDF surgery from February 2014 to November 2016 were enrolled in the present study.All patients took the MRI at both flexion and neutral position pre-operation and MRI at flexion position post-operation.The measured parameters related to performance of"loss of attachment"include:the distances between the posterior edge of the spinal cord and the cervical spinal canal(x),the anterior and posterior wall of the cervical spinal canal(y),the anterior-posterior(a)and the transverse diameter(b)of spinal cord cross sections.The value of the cervical spinal cord deformation(flexion position a/b)and the cervical spinal cord forward movement(flexion position x/y-neutral position x/y)were calculated,and the centrums refer to the performance of"loss of attachment"were also recorded.DASH scores and grip strength on both sides were recorded before and 1 year after operation.The 26 patients were divided into two groups,17 patients(17/26,65.4%)in improvement group with the decreased DASH scores and the other 9 patients(9/26,34.6%)in no improvement group.Logistic regression and ROC curve were used to analyze the influence factor of anterior cervical discectomy and fusion(ACDF)surgery on patients with Hirayama disease.Results After surgery,the value of a/b significantly increased(t=4.27,P=0.001)and x/y significantly decreased(t=10.25,P=0.001).The performance of"loss of attachment"in 88.5%(23 of 26)patients disappeared after surgery,while the DASH score(P=0.06),and the grip strength of severe and mild side(P=0.36 and P=0.42)shew no obvious change.65.4%(17 of 26)patients shew a decrease in DASH scores after operation,the remaining 34.6%(9 of 26)patients shew no obvious change,several even with a mild increase.The segments refer to performance of"loss of attachment",the value of the cervical spinal cord deformation and the cervical spinal cord forward movement shew a difference between the two group(t=-5.56,P=0.001;t=3.06,P=0.005;t=-3.76,P=0.001).The logistics regression analysis with the above three independent variable confirmed that the value of segments that refer to"loss of attachment"was the factor of the post-operative efficacy of ACDF surgery on patients with Hirayama disease(OR=6.963,P=0.001).And the ROC curve shew AUC=0.902,Jordan index=0.83,critical value=4.5.Conclusion The anterior cervical discectomy and fusion(ACDF)surgery can effectively improve the loss of attachment at the surgical segments,and prevent the progress of upper limb dyskinesia.And range of the longitudinal separation refers to"loss of attachment"can impact the outcomes of ACDF surgery,more segments for fusion may be need in order to improve the outcomes of those patients with the range more than 5 segments.