青少年脊柱側彎患者之肩帶動態學、體表肌電變化及功能之改變

Abstract

青少年脊柱側彎在原發性的脊柱側彎(idiopathic scoliosis)族群中約佔了85%，許多青少年甚至不清楚自己是否有脊柱側彎的情形。脊柱側彎除了脊柱在身體冠狀面的側彎外，椎體本身也會產生旋轉。脊柱側彎不僅會影響個體在發育中的外觀，也會使得青少年本身胸廓構造形成畸形，在胸椎側彎角度過大時，往往會因胸廓的變形，進一步影響藉由肌肉附著於胸腔外的肩胛骨位置，使側彎凸側之肩胛骨隆起。推測長期肩胛骨位置的不對稱，會造成肩帶(shoulder girdle)肌群張力的不協調，進而使肌肉收縮產生動作時發生異常，但過去卻很少有文獻直接探討脊柱側彎與肩帶活動之間的相關性。本研究目的在比較青少年脊柱側彎的個案與脊柱正常青少年在肩帶之動態學、體表肌電圖與功能之異同之處，及脊柱側彎患者中，其兩側肩帶之動態學、體表肌電圖與功能的不同。研究方法：搜尋青少年(12~25歲)脊柱側彎患者，於X光片影像學上胸椎側彎大於二十度以上的患者為受測對象，另外並搜尋無脊柱側彎之青少年做為對照組。使用磁場定位系統(Electromagnetic-based Measurement System, FASTRAK System)測試兩組於肩關節前屈(flexion)、肩胛骨面外展(scaption)及冠狀面外展(abduction)的動作測試，針對肩帶動態學作比較；另外，同時以體表肌電圖(Surface Electromyography)偵測上斜方肌、下斜方肌，前鋸肌及中段三角肌在前述肩關節三個動作進行時，其肌肉收縮的動作前置時間(pre-motor time)與收縮程度比例；並填寫肩關節功能性指數評估表(FLEX-SF) 評估肩關節之功能。統計方法為1.) 利用independent t-test比較脊柱側彎組之脊椎凸側、凹側與對照組同側肩帶之動態學、體表肌電圖及功能的差異；2.) 利用paired t-test比較脊柱側彎組之兩側肩帶在動態學及體表肌電圖上的差異；及3.)以相關檢定脊柱側彎組中，胸椎側彎之肩帶動態學及肌電變化與功能之相關。結果發現：1.)在脊柱側彎組中，脊柱側彎凹側之肩胛骨位移明顯較凸側來得少，且在測試過程中，除肩關節前屈外，肩胛骨面外展及冠狀面外展時的受測肌群在側彎凹側的肌肉也較慢產生肌電位的變化，而在此側穩定肩胛骨的肌肉也有較多的介入；2.)脊柱側彎組側彎凹側的肩關節，較對照組同側的功能還差；兩組受測者兩側肩帶的動態學並無太大的差異，然而在側彎凹側的肩關節與正常人同側的體表肌電變化上，仍有些不同之處；3.)針對脊柱側彎組在側彎凹側的肩帶動態學及體表肌電變化與功能的相關上，在肩帶動態學與其功能並無顯著的相關性；而在肌電變化與功能的相關上，下斜方肌在外展動作下，與肩關節功能有中度以上的相關性，中段三角肌及前鋸肌也在部分動作中與其有輕度的相關。結論與討論：脊柱側彎族的確影響肩帶的功能運作，在臨床上建議增加側彎凹側之上斜方肌與前鋸肌及側彎凸側之前鋸肌的肌力訓練，並減少側彎凹側下斜方肌的肌肉收縮程度，如此，一方面使側彎凸側肩胛骨的位置趨於正常，另一方面則對側彎凹側肩胛骨的活動做再教育(re-education)訓練，預期希望能改善肌肉電位的異常。雖然我們的結果在肩帶動態學變化與其功能的相關性並不顯著，但在未來的研究，可以擴大脊柱側彎受試族群，依不同之脊柱側彎程度分級討論，並考量肩關節附近肌群肌力的影響及深層肌肉的肌肉電位變化情形。

Eighty-five percent idiopathic scoliosis present in adolescent stage. Scoliosis is a side-to-side curvature of the spine in coronal plane. It usually happens with rotation of the vertebrae body. The effects of scoliosis are not only in the outside looking of the body, but also loss of both volume and function of the thorax. Severe scoliosis may result in the deformity of the rib cage and associated muscles. So, the convex side of spine in the scoliosis will make the scapula humping. It is supposed muscles’ tension around shoulder girdle is imbalanced because of asymmetric position of scapula. And that would result in abnormal muscle contraction and shoulder motion. There were few studies discussed about the relationship between the scoliosis and the motion of shoulder girdle. The purpose of the study was to compare the shoulder kinematics, surface electromyography(sEMG), and function of shoulder girdle between both sides of the adolescent idiopathic scoliosis(AIS) group and between the AIS group and normal subjects. The AIS group with Cobb angle more than 20 degree and the control group without scoliosis were recruited in this study. With FASTRAK motion system, they performed shoulder flexion in sagittal plane, abduction in scapular plane and coronal plane. At the same time, the muscular activities of upper trapezius, lower trapezius, serratus anterior and middle deltoid were detected by sEMG. Additionally, the shoulder function was evaluated by Flexilevel Scale of Shoulder Function. The collected data was analyzed by SPSS 11.0. Independent t-test was used to compare those outcomes between the AIS group and control group. Paired t-test was used to compare those outcomes of both shoulder girdles in AIS group. Pearson correlation was used to demonstrate the relationship between kinematics, sEMG and function of shoulder girdle in the AIS group. The results showed that 1.) the scapular movement during arm elevation was less in concave side than in convex side in AIS group. During tests, the onset of the muscles activities around shoulder in concave side was longer than that in convex side. And the higher muscular activities around shoulder in concave side compared to convex side. 2.) Comparison between the shoulders in AIS group and in the same side of normal group, there were some significant differences in sEMG, but not in kinematics. 3.) There was no relationship between shoulder function and kinematics in concave side in AIS. But, there was moderate to good relationship between shoulder function and sEMG finding of lower trapezius in concave side. Additionally, serratus anterior and middle deltoid have fair relationship with shoulder function in sEMG premotor time in abduction and scaption in concave side. Thus shoulder dysfunction was evident through our investigation. In clinical implication, we suggest that to increase the muscle power of serratus anterior on both sides and upper trapezius of concave side and to relax lower trapezius of concave side. It’s for improving the mal-alignment of scapula in convex side and re-education for the shoulder motion in concave side. In the future study, we should increase the sample size in AIS and consider the influence of muscle power in shoulder girdle. And also, the deep layer muscle group around shoulder may be the effective factors on function.