Abstract
目的
评估肩袖组织损伤程度与肱骨头上移距离之间的关系。
方法
选取2015年9月至2016年5月北京大学人民医院创伤骨科收治的肩袖损伤患者30例,均已行患侧肩关节磁共振及X线检查。将患者根据X线正位片测量所得的肱骨头上移系数(upward migration index,UMI),即肱骨头中心至肩峰距离与肱骨头半径的比值分为3个小组,每组10人,组1:1.2≥UMI >1,组2:1.4≥UMI >1.2,组3:UMI >1.4,进行Spearman等级相关分析,判定不同的UMI值与肩袖组织脂肪变程度、肩袖撕裂范围、撕裂处冈上肌厚度之间的关系。
结果
在X线正位片上,平均UMI值为1.33(范围1.02~1.51,标准差为±0.22),UMI值与肩袖组织撕裂的大小呈负相关(R=-0.584,P<0.01),与冈上肌脂肪变程度呈负相关(R=-0.312,P=0.033),而与磁共振上撕裂处冈上肌厚度并无相关性(R=0.127,P=0.071)。
结论
UMI与肩袖撕裂及肩袖脂肪变程度存在相关性,UMI值与肩袖组织撕裂大小和冈上肌脂肪化程度呈负相关,其数值减小是肩袖撕裂及脂肪化退变的可靠标志。当患者因急性肩痛就诊时,门诊医师可结合临床表现、体格检查及X线影像学检查结果作出初步判断,对初步筛查肩袖损伤及指导进一步治疗具有重要意义。
Keywords: 肩袖损伤, 肱骨, 肩关节, 肩痛, 腱损伤, 诊断显像
Abstract
Objective
To evaluate the association between rotator cuff tear and the proximal migration of humeral head.
Methods
In this research, we retrospectively selected 30 patients with unilateral rotator cuff tear in Peking University People’s Hospital from September 2015 to May 2016, who received magnetic resonance imaging (MRI) and X-ray of the painful shoulder before enrollment in this study, the duration between the two examinations was no longer than 1 week, and also there was no past history of surgery in the selected shoulders. There was no other exclusion criteria. Upward migration index (UMI) was the ratio between the distance of humeral head center to the lower surface of acromion, and the radius of humeral head circle, which could help to minimize the effect of anatomy difference and imaging magnification, compared with the traditional acromiohumeral distance (AHD). Then we introduced this index to stratify the selected 30 patients into 3 groups , and each group contained 10 patients, UMI of group 1 was >1 and ≤1.2, UMI of group 2 was >1.2 and ≤1.4, UMI of group 3 was >1.4. As the supraspinatus was most commonly affected by pathological change among the four rotator cuff tendons, we took it as the research object. Then we used the Spearman correlation analysis to evaluate the relationship between UMI and fatty degeneration, rotator cuff tear size and the thickness of ruptured supraspinatus tendon from X-ray and MRI.
Results
In the A-P view, the average UMI was 1.33 (1.02-1.51, SD: ±0.22). UMI and the tear size had a significant negative correlation (R=-0.584, P<0.01), and also there was a negative correlation between the fatty degeneration of the supraspinatus (R=-0.312, P=0.033). However, there was no correlation between UMI and the thickness of ruptured supraspinatus (R=0.127, P=0.071).
Conclusion
UMI is related with the fatty degeneration of supraspinatus and the tear size. The reduction of UMI is a predictable and reliable mark of rotator cuff tear and degeneration in clinic. Physicians can use physical examination and X-ray first when facing the patients with shoulder pain, which is convenient and helpful for evaluating rotator cuff tears.
Keywords: Rotator cuff injuries, Humerus, Shoulder joint, Shoulder pain, Tendon injuries, Diagnostic imaging
肱骨头上移是晚期肩袖损伤患者中常见的现象[1,2],但出现肱骨头移位的具体机制不明,可能的原因包括肌腱断裂后的空间缺损、对抗三角肌牵拉力量减弱等。磁共振成像(magnetic resonance imaging,MRI)是目前临床中主要的确诊手段,但检查费用昂贵且预约时间长。当患者因急性肩痛就诊时,X线片由于其便捷和直观的特性,常成为首先进行的辅助检查方式。肩关节外科医师可通过临床表现、体格检查结合X线影像学检查,初步筛查肩袖损伤,并指导进一步治疗[3,4,5]。目前肱骨头上移大小的测量主要是靠测量肱骨肩峰距离(acromio-humeral distance, AHD)实现的,即肩峰下缘到肱骨头软骨下皮质的最短距离。有研究表明,在正位片上AHD小于7 mm提示肩袖撕裂[3,4],另有一些研究表明,肱骨肩峰间隙的变窄与肩袖组织退变相关[1,6]。目前仍然不清楚肱骨头上移后肩袖损伤位置、撕裂大小、肩袖肌肉脂肪化退变中哪一项是最主要的结构改变,且很少有研究对此作出具体数值化的定量分析。冈上肌在肩峰下间隙走行,是最易受损伤的肩袖肌腱[7]。本文以冈上肌为研究对象,目的是评估肩袖组织损伤程度与X线片上肱骨头-肩峰间隙之间的关系,对今后门诊、急诊临床初步判断肩袖损伤具有重要意义。
1. 资料与方法
1.1. 一般资料
本研究纳入北京大学人民医院创伤骨科2015年9月至2016年5月单侧肩袖损伤患者30例(12例男性,18例女性,50~70岁,平均年龄58.6岁)。患者就诊前均具有不同程度的患侧肩关节疼痛,结合肩关节体格检查,高度怀疑冈上肌损伤,后进一步行影像学检查证实。纳入标准:入选前半年内行MRI及X线检查,证实存在肩袖撕裂。X线检查患者前臂中立位摄取正位片,同时摄取冈上肌出口位,而MRI扫描时间不能超过摄取X线平片后1个月,同时没有患侧肩关节手术史。
纳入患者共分为3组,每组10人(4例男性、6例女性), 3组间年龄经单因素方差分析差异无统计学意义(F=0.853,P=0.437)。由于不同性别、年龄、人种的肱骨头大小可能存在差异,为避免不同人的解剖差异及X线片的放大作用等因素对肩峰下间隙距离的影响,我们引入了肱骨头上移系数(upward migration index,UMI)以评估肱骨头上移程度,方法为在肱骨头周围绘制同心圆,以确定肱骨头中心,CA测量值为X线图像中测得的肱骨头中心与肩峰前角下方之间的直线距离,再除以肱骨头同心圆半径R,即得到UMI(CA/R),具体见图1[8]。
1.
通过正位X线片测定肱骨头半径及肱骨头中心至肩峰距离
Measurement of CA distance and the radius of humeral head on X-ray
A, acromion; R, radius of humeral head; C, center of humeral head; CA, the distance between the center of humeral head and anterio-lateral acromion.
将3组根据X线正位片上测量所得的UMI分层,组1:1.2≥UMI >1,组2:1.4≥UMI >1.2,组3:UMI >1.4。影像学检查数据均由电子数据库内提取。
1.2. MRI检查
以冈上肌为研究对象,MRI分析肩袖撕裂大小、位置以及肌肉脂肪化程度等。撕裂的程度是在斜矢状位及斜冠状位缺损最大的部位测量的,计量单位为cm2。肌肉脂肪化退变程度使用由Goutallier等[9]定义的分型,这种分型基于与肌肉相关的脂肪含量,0级提示无脂肪退化,1级有脂肪变倾向,2级脂肪含量少于肌肉含量,3级肌肉含量和脂肪含量相当,4级脂肪含量多于肌肉含量。Goutallier等[9]的分型原本是为了描述CT表现,之后由Fuchs等[10]对MRI结果进行了描述。如果冈上肌和肩胛下肌前部脂肪变退化的程度不同,级别最高的区域可用于分型。最后测量冈上肌撕裂处残存部分肌腱的厚度,取数值最大的层面。对于肌腱完全断裂的病例,则测量肌腱撕裂断端上、下表面的最大距离,同样取数值最大的层面,记录相应数值。
1.3. 数据分析
应用SPSS 15.0软件进行Spearman等级相关分析,判定不同的UMI值与肩袖组织脂肪化退变程度数据之间的关系,也用于判定UMI值与撕裂程度、冈上肌厚度间的关系。
2. 结果
2.1. UMI测定
在传统X线正位片上,平均UMI值为1.33(范围1.02~1.51,标准差为±0.22),在出口位片上平均UMI值为1.29(范围1.03~1.54,标准差为±0.27)。
2.2. 不同组冈上肌全层撕裂情况
在组1里,冈上肌腱全层撕裂出现于70%的患者(7/10), 组2和组3中全层撕裂的概率明显低于组1(表1)。各组患者冈上肌损伤试验(Jobe试验)阳性的例数为:组1中8例,组2中8例,组3中7例。
1.
不同组冈上肌全层撕裂及体格检查情况比较
Comparison of full-thickness tear and physical examination between different groups
| UMI | Full-thickness tear of supraspinatus |
Jobe test positive |
| UMI, upward migration index. | ||
| 1<UMI≤1.2 (n=10) | 7 (70%) | 8 (80%) |
| 1.2<UMI≤1.4 (n=10) | 3 (30%) | 8 (80%) |
| UMI>1.4 (n=10) | 2 (20%) | 7 (70%) |
2.3. 不同组间肩袖撕裂范围比较
组1肩袖撕裂的范围为1.3~38.5 cm2 (平均18.8 cm2),组2肩袖撕裂的范围为4.0~29.5 cm2 (平均6.4 cm2),组3肩袖撕裂的范围为0.4~17.3 cm2 (平均3.3 cm2)。
2.4. 不同组间肌肉脂肪化退变程度
30例患者中有10例出现冈上肌肌肉潜在的脂肪化退变(Goutallier 2级以上),其中组1有5例,组2有3例,组3有2例(表2)。
2.
不同组间冈上肌脂肪化退变程度比较
Comparison of fatty degeneration between different groups
| UMI | Fatty degeneration (Goutallier classification) |
||||
| 0 | 1 | 2 | 3 | 4 | |
| UMI, upward migration index. | |||||
| 1<UMI≤1.2 (n=10) | 2 | 3 | 4 | 0 | 1 |
| 1.2<UMI≤1.4 (n=10) | 5 | 2 | 2 | 1 | 0 |
| UMI>1.4 (n=10) | 6 | 2 | 2 | 0 | 0 |
2.5. 冈上肌肌腱厚度比较
测量撕裂处冈上肌肌腱的厚度(取最大值),组1的冈上肌厚度为1.3~3.5 cm (平均2.2 cm), 组2的冈上肌厚度为1.6~3.3 cm(平均2.8cm), 组3的冈上肌厚度为1.2~4.0 cm (平均2.5 cm)。
2.6. 不同MRI表现与UMI之间的关联
通过Spearman等级相关分析,将X线平片上UMI值与肩袖结构及MRI影像结果之间进行相关性分析(表3)。UMI值与肩袖组织撕裂的大小有较高的关联系数(R=-0.584,P<0.01),呈负相关;UMI值与冈上肌退变程度同样呈负相关(R=-0.312, P=0.033);UMI值与肩袖MRI上冈上肌厚度并无相关性(R=0.127,P=0.071)。
3.
不同MRI表现与UMI之间的关系
Correlation between MRI and UMI
| Items | UMI | Tear size | Fatty degeneration |
Thickness of supraspinatus |
| a, significance at 0.01 level (bilateral); b, significance at 0.05 level (bilateral). MRI, magnetic resonance imaging; UMI, upward migration index. | ||||
| Correlation coefficent | 1.000 | -0.584a | -0.312b | 0.127 |
| Significance level (bilateral) |
- | <0.01 | 0.033 | 0.071 |
3. 讨论
1970年,Weiner等[11]首先描述了缩小的AHD距离和肩袖撕裂之间的关系。盂肱关节动力学改变常出现于肩袖撕裂的进展期[12]。一项基于关节镜检查的研究发现,完整的平均AHD距离是10.5 mm,然而当出现肩袖肌腱撕裂时,平均距离只有8.2 mm[13]。但由于不同人的解剖差异及X线片的放大作用等因素对AHD距离存在影响,我们认为在X线正位片上单纯直接测量AHD是不准确的,因此我们引入了UMI以评估肱骨头上移程度。UMI为比例数值,可以纠正体位、个体差异及缩放比例等带来的影响,通过它判断肱骨头上移程度是可靠和准确的。
在过去的数十年内,有许多研究强调了早期诊断及治疗肩袖撕裂的重要性,以提升修复后的效果[14,15]。B超及MRI在诊断肩袖撕裂时具有高度的特异性和准确性,是目前主要的确诊手段,但当患者因急性肩痛就诊时,X线片由于其便捷和直观的特性,且可以同时观察骨性结构,常成为首先进行的辅助检查方式,因而,正确摄取X线片成为明确诊断及进一步检查和治疗的关键。体格检查也是重要的术前判断依据,其中Jobe试验在检测冈上肌撕裂中有较高的敏感性和特异性。检查时患者肩关节外展90°前屈30°并拇指向下,双上肢完全伸直,对抗检查者施加的向下压力,对比双侧的力量。检查时出现疼痛并伴有明显的力量减弱为阳性。本研究纳入的患者均存在不同程度的冈上肌肌腱损伤,其中有近80%的患者存在Jobe试验阳性。这种体格检查只能初步判断损伤性质,即有无肩袖损伤,而单纯通过肌力水平判断肩袖组织损伤的具体程度则存在较大的不准确性。因此,在门诊初诊过程中,如正位X线片上出现UMI值减小,结合体格检查阳性体征时,可初步判断肩袖损伤程度,为早期准确诊断及制定后续治疗方案提供重要参考。
本研究结果表明,UMI值和肩袖肌肉脂肪化退变相关,但肩峰下间隙同冈上肌退变之间的关联比之前报道的要小。在一项CT的研究中,Nové-Josserand等[6]发现冈上肌肌肉脂肪退变后有100%的间隙缩窄。本研究中,正常肩峰下间隙也可以在冈上肌2期或3期脂肪化退变的患者中见到,具体原因仍不明了,需要在今后临床工作中进一步观察分析。
一些人为的干预措施,如肩峰成形术及其他肩袖损伤后的康复治疗措施,主要目的是增大肱骨头肩峰间隙,以期能够改善肩痛症状及肩关节功能[7]。肩关节外科医师通过传统的X线平片评估肩峰下间隙,以评估成功修复肩袖组织的可能性。以往Goutallier等[16]的研究表明,AHD小于6 mm可提示肩袖较大范围撕裂,且不适于手术修复,但本研究中的病例出现了例外情况,肩峰下间隙小于6 mm的9例患者中有2例为部分肩袖撕裂。本研究中UMI<1.2的患者中有超过70%的患者出现冈上肌腱全层撕裂,冈上肌全层撕裂的数量随着UMI增大(1.2以上)而下降。在各组中均出现了巨大肩袖撕裂或肌肉脂肪化退变,表明传统X线平片上UMI值缩小可以为我们提供肩袖组织完整性的信息,协助诊断及制定治疗方案,但这不能作为诊断及肩袖修复手术决定的唯一标准,影响最终预后的因素尚包括年龄、肌肉力量、性别等[17],需要外科医师综合多方面因素考虑,做出准确的判断。
本研究具有一定局限性,纳入的患者共30例,样本量较小,存在不均一性;另外,本研究为理论性结论,今后尚需进一步临床验证及生物力学研究。
UMI与肩袖撕裂及肩袖脂肪退化程度存在相关性,UMI值与肩袖组织撕裂大小和冈上肌脂肪化退变程度呈负相关,其数值减小是肩袖撕裂及脂肪化的可靠标志。当患者因急性肩痛就诊时,门诊医师可结合临床表现及X线影像学检查结果,对初步筛查肩袖损伤及指导进一步治疗具有重要意义。
(本文编辑:任英慧)
Funding Statement
国家重点基础研究发展计划(973计划)（2014CB542201）; 国家高技术研究发展计划(863计划)（SS2015AA020501）; 国家自然科学基金（31571235）; 国家自然科学基金（31571236）; 国家自然科学基金（31271284）; 国家自然科学基金（31171150）
the National Basic Research Program of China(973 Program)(2014CB542201); the National High Technology Research and Development Program of China(863 Program)(SS2015AA020501); the National Natural Science Foundation of China(31571235); the National Natural Science Foundation of China(31571236); the National Natural Science Foundation of China(31271284); the National Natural Science Foundation of China(31171150)
Contributor Information
张 培训 (Pei-xun ZHANG), Email: zhangpeixun@126.com.
姜 保国 (Bao-guo JIANG), Email: jiangbaoguo@vip.sina.com.
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