慢性頸痛患者上頸椎背側肌群之厚度變化量─超音波影像量測

Abstract

背景：過去研究顯示頸部深淺層肌群功能角色不同。慢性頸痛患者之頸部腹側肌群發現有淺層肌群過度活化、深層肌群低度活化的現象，雖於下頸椎背部肌群有類似現象，上頸椎背側肌群尚未有研究。上頸椎背側肌群有深、中、淺三層，慢性頸痛是否改變各層間活化關係則不清楚。利用動態超音波能以非侵入方式量測不同深淺層肌肉於動作時型態學變化，觀察肌肉活化情形。以動態超音波量測下頸椎背側肌群之厚度已顯示有很好的信度，但量測上頸椎背側肌群厚度之方法學尚未建立。此外，上頸椎背側肌群厚度參數與其他因子之相關性，如性別、兩側差異、人體測量學參數、情緒分數、頭前傾角度等，亦尚未完全了解。 目的： （1）檢測以動態超音波量測上頸椎背側肌群之同天施測者內信度；包括靜態及50%最大上頸椎伸直力量時厚度；（2）比較靜態及50%最大上頸椎伸直力量時厚度之差異；（3）建立上頸椎背側肌群之厚度量測與性別、兩側差異、人體測量學參數、情緒分數、頭前傾角度等因子之相關性；（4）比較慢性頸痛患者與無頸痛受試者其上頸椎背側肌群之厚度參數之差異。 方法：信度實驗徵召10名無頸痛受試者，主要實驗另徵召慢性頸痛患者與無頸痛受試者各29名。上頸椎背側肌群之厚度以動態超音波（HDI 5000, ATL, USA）量測。上頸椎背側肌群可分為三層，包含深層之頭大直肌（RCPM）與頭上斜肌（OCS）、中層之頭半棘肌（SScap）、及淺層之頭夾肌（SPcap）。厚度參數包含頸椎未承重（趴姿，Tpr）、頸椎承重下（坐姿，Tsr）之靜態厚度，50%最大上頸椎伸直力量動作時厚度（Tsm），及從休息到50%最大上頸椎伸直力量之收縮厚度變化量（Tcc），與從未承重至承重姿勢改變時厚度變化量（Tcp）。信度以組內相關係數、測量標準誤、受試者間變異係數檢定；以Pearson相關係數分析上頸椎背側肌群之厚度量測參數與各因子之相關性，以逐步迴歸分析找出對各量測參數最具影響力之參數。分別以獨立t檢定及配對t檢定檢驗性別及測試邊之差異。以共變數分析檢測控制干擾因子下不同組別與不同肌肉之厚度量測參數差異。 結果：靜態（Tsr）及50%最大上頸椎伸直力量時厚度（Tsm）之組內相關係數分別為0.77-0.99及0.82 to 0.97；測量標準誤分別為0.16 mm-0.61 mm及0.32 mm-0.70 mm；受試者間變異係數分別為3.5%-6.1%及3.7%-6.4%。上頸椎背側肌群Tsm皆大於相對應之Tsr （p< 0.005-0.029）。未承重及承重下靜態厚度皆為男性大於女性（Tpr，p<0.0005-0.004；Tsr，p<0.0005-0.011），但兩側無顯著差異（p>0.05）。體重（Tpr，r=0.37-0.61，p<0.0005-0.004；Tsr， r=0.46-0.65，p<0.0005）及身高（Tpr，r=0.37-0.59，p<0.0005-0.001；Tsr，r=0.36-0.53，p<0.0005-0.006）皆與Tpr及Tsr相關，但與Tcc及Tcp無顯著相關或僅有低度相關性。身體質量指數與厚度參數之相關性則皆較身高及體重低。情緒分數中僅有貝氏焦慮量表分數與淺層之頭夾肌之靜態厚度（r=0.36-38，p=0.003-0.006）相關。逐步迴歸分析顯示體重為Tpr及Tsr最重要的影響因子，疼痛為Tcc最重要的影響因子。因此，比較慢性頸痛患者與無頸痛受試者組間差異時，將靜態及最大上頸椎伸直力量時厚度50%厚度以體重標準化，並將貝氏焦慮量表分數以共變數控制。控制焦慮影響後，慢性頸痛患者相較於無頸痛受試者其體重標準化之未承重（Tpr/w）、承重情況下（Tsr/w）之靜態厚度無顯著差異；上頸椎淺層頭夾肌之Tcc較大（慢性頸痛患者與無頸痛受試者分別為0.06 ± 0.04cm與0.03 ± 0.02cm，p=0.007），中間層頭半棘肌（慢性頸痛患者與無頸痛受試者分別為0.13 ± 0.06cm與0.20 ± 0.07cm，p<0.0005）及深層頭大直肌（慢性頸痛患者與無頸痛受試者分別為0.20 ± 0.08cm與0.31 ± 0.12cm，p=0.001）與頭上斜肌（慢性頸痛患者與無頸痛受試者分別為0.11 ± 0.10cm與0.22 ± 0.12cm，p=0.010）之Tcc較小；無論深淺層肌群之Tcp則皆較無頸痛受試者小（p=0.048）。 結論：無論是靜態或動態，以動態超音波量測上頸椎背側肌群有良好信度。無論是非承重或承重情況下，體重與性別皆顯著影響其靜態時厚度，但不影響厚度變化量。焦慮程度會影響淺層頭夾肌之靜態厚度。在控制焦慮影響下，慢性頸痛患者於上頸椎伸直動作時，上頸椎淺層背側肌群之收縮厚度變化量增加、中間層及深層之收縮厚度改變量減少，此結果可提供肌肉控制失能之證據。未來研究可建立慢性頸痛患者肌肉控制失能之治療計畫。

Background: Functional role of deep muscles in cervical region has been suggested to provide spinal stabilization. Patients with chronic neck pain have been found enhanced superficial and reduced deep muscle activation of their ventral neck muscles. Similar pattern of change in muscle activation has been demonstrated in the dorsal neck muscles in lower cervical spines. Whether the adaptive change of dorsal muscles in upper cervical spines would show in patients with chronic neck pain was unknown. Using real-time ultrasonography could measure the morphological changes of the superficial, intermediate, and deep layers of dorsal neck muscles in a non-invasive way. Measuring the thickness of the lower dorsal neck muscles during contraction using ultrasonography has been demonstrated good reliability. The methodology for thickness measurements for the upper dorsal neck muscles, however, has not been established. Whether the gender, side-to-side difference, anthropometry measures, psychological scores, and forward head posture influence the thickness measurements remained unclear. Purposes: (1) To examine the intraday-intrarater reliability of measuring thickness of the upper dorsal neck muscles at static condition as well as at 50% MVC of upper cervical extension using real-time ultrasonography. (2) To compare the thickness at static condition (Tsr) and at 50% MVC (Tsm). (3) To determine the relationship among the thickness measurements, gender, side-to-side difference, anthropometric measures, psychological scores and forward head posture. (4) To compare the thickness measurements between patients with chronic neck pain and asymptomatic subjects. Methods: Ten subjects (aged 21-30 years) without neck pain and headache in recent 3 months were recruited in the reliability study. Twenty-nine patients with chronic neck pain aged 24.3 ± 4.2 years old and twenty-nine asymptomatic subjects aged 27.0 ± 3.9 years old were recruited in the main study. Their upper dorsal neck muscles were measured using ultrasonography (HDI 5000, ATL, USA), including the splenius capitis (SPcap), semispinalis capitis (SScap), rectus capitis posterior major (RCPM), and oblique capitis superior (OCS). The thickness measurements included static thickness in unloading (prone position, Tpr) and loading of the cervical spines (sitting position, Tsr) conditions, the thickness at 50% MVC (Tsm) of upper cervical extension as well as the change in thickness from static condition to 50% maximal voluntary contraction (MVC, Tcc) and between unloading and loading conditions (Tcp). Intraclass correlation of coefficient (ICC), standard error of measurement (SEM), and within-subject coefficient of variation (CVw) were used to examine the reliability. Pearson correlation coefficient was used to examine the relationship among the thickness measurements of the upper dorsal neck muscles, age, anthropometric measures, psychological scores, and forward head posture. Stepwise regression model was used to find out the most influential factor for each thickness measurement. The differences of the thickness measurements between genders and between sides were examined by independent t-test and paired t-test, respectively. Analysis of covariance (ANCOVA) was used to compare the difference on thickness measurements between groups and muscles with controlling the confounders. Results: The ICC3,1 values were ranged from 0.77 to 0.99 for Tsr, and from 0.82 to 0.97 for Tsm of the upper dorsal neck muscles. The SEMs for Tsr and Tsm were 0.16 mm-0.61 mm and 0.32 mm-0.70 mm, respectively, while the CVws were 3.5%-6.1% and 3.7%-6.4%, respectively. The thicknesses of the upper dorsal neck muscles at 50% MVC (Tsm) were all significantly higher than the corresponding ones at static condition (Tsr, p<0.005-.029). Tpr (p<0.0005-0.004) and Tsr (p<0.0005-0.011) of the upper dorsal neck muscles were significantly different between genders, but not when normalized for body weight. The side-to-side differences of the thickness measurements were not significant or small. The correlation of body weight (Tpr: r=0.37~0.61, p<0.0005~0.004, Tsr: r=0.46~0.65, p<0.0005) and body height (Tp: r=0.37~0.59, p<0.0005~0.001, Tr: r=0.36~0.53, p<0.0005~0.006) with Tpr and Tsr were significant, whereas the correlation with Tcc and Tcp were small or not significant. The correlation of BMI with thickness measurements seemed weaker than body weight and height. Among the psychological scores, only score of the Beck Anxiety Inventory was correlated with the static thickness for SPcap. Body weight was the most influential factor for Tpr, Tsr, and Tsm, whereas neck pain was the most influential factor for Tcc and Tcp. The between-group comparison on the thickness measurements was therefore normalized with weight (for Tpr, Tsr, and Tsm) and controlled with the effect of anxiety (for all thickness measurements). After controlling the effect of anxiety, no significant difference of the normalized static thickness either in unloading (Tpr/w) or loading (Tsr/w) condition between groups. Patients with chronic neck pain had larger (p=0.007) Tcc for the superficial dorsal neck muscle (SPcap, 0.06 ± 0.04cm and 0.03 ± 0.02cm for symptomatic and asymptomatic subjects, respectively), and smaller Tcc (p<0.0005-0.010) for the intermediate (SScap, 0.13 ± 0.06cm and 0.20 ± 0.07cm for symptomatic and asymptomatic subjects, respectively), and the deep ones (RCPM, 0.20 ± 0.08cm and 0.31 ± 0.12cm for symptomatic and asymptomatic subjects, respectively; OCS, 0.11 ± 0.10cm and 0.22 ± 0.12cm for symptomatic and asymptomatic subjects, respectively) than asymptomatic subjects. Tcp was significantly smaller (p=0.048) in patients with chronic neck pain than asymptomatic subjects. Conclusion: Measuring the thicknesses of the upper dorsal neck muscles using ultrasonography was reliable both at static condition and during contraction. Significant influence of body weight and gender on the static thicknesses was demonstrated both in unloading and loading conditions, but not for the change in thickness from static condition to 50% MVC. Anxiety was correlated to the static thickness of the superficial dorsal neck muscle, the SPcap. After controlling the effect of anxiety, the changes in thickness during upper cervical extension in patients with chronic neck pain were increased for the superficial muscles (SPcap) and were decreased for the deeper ones (SScap, RCPM and OCS). This altered relationship of change in thickness between superficial, intermediate and deep muscles in upper dorsal neck muscles may provide an evidence of the muscle dysfunction in patients with chronic neck pain. Future studies may develop a treatment program for the muscle dysfunction in patients with chronic neck pain.