慢性下背痛病人腹橫肌之前後肌肉筋膜交點型態學變化—動態超音波研究

Abstract

背景：腹橫肌是提供脊椎穩定最深層之腹肌。腹橫肌藉由胸腰筋膜連結至脊椎上而形成了一個「肌肉-筋膜腰帶系統」。藉著此系統，腹橫肌可調節腹內壓及脊椎節間動作的控制並達成脊椎的穩定。下背痛病人的腹橫肌表現較正常人差，且胸腰筋膜上呈現沾黏等退化情形。但前人的研究主要探討腹橫肌前側端點的表現，將後側端點視為固定端，而忽略了肌肉-筋膜腰帶系統的完整性。此外，筋膜放鬆術應可改善筋膜的沾黏情形並回復肌肉筋膜腰帶系統的張力平衡。 目的：本實驗的目的為：1) 建立以超音波影像測量後側腹橫肌信度；2) 探討 腹橫肌前後端點之間超音波測量參數之相關性；3) 比較慢性下背痛病人與無症狀受試者之腹橫肌前後筋膜肌肉交點肌肉厚度、滑動及肌肉長度；4) 在一分鐘的筋摸放鬆術後，腹橫肌表現的立即改變。 方法：信度實驗收取10位無下背痛之健康受試者，在腹部內縮的動作下，建立以超音波測量後側腹橫肌單一測試者信度。主要實驗收取20位慢性下背痛及20位無下背痛之健康人。受試者於雙腳屈膝躺姿下，進行腹部內收動作並量測腹橫肌前後端點的休息及收縮肌肉厚度、肌肉筋膜交點移動及肌肉長度改變。在施予筋膜放鬆術於胸腰筋膜中點一分鐘後，立即量測放鬆後腹橫肌前後端點表現及筋膜交點移動模式變化。信度實驗以組內相關係數(Intraclass correlation coefficient, ICC(3,3)來分析。腹橫肌前後端點之間超音波測量參數之相關性以Pearson correlation分析。以三尾變異數分析(3-way ANOVA)作在兩組之間在前後側肌肉厚度、筋膜端點滑動之差異比較。兩組間放鬆前後肌肉長度變化及筋膜交點移動模式將使用雙尾變異數分析。α值設在0.05。 結果：以超音波量測無下背痛受試者中，腹橫肌後側的肌肉厚度變化及肌肉筋膜交點滑動呈現良好的信度 (ICC(3,3)=0.888-0.978)。本次實驗收錄的健康受試者中，腹橫肌前後端點之間超音波測量參數呈現中度至高度相關(Pearson correlation(r)=0.41-0.74)。在組間的比較中，下背痛的受試者的前後側肌肉收縮厚度、厚度變化及肌肉筋膜交點的滑動，在筋膜放鬆前後皆較無症狀受試者小(p<0.005)。兩組在筋膜放鬆後在肌肉收縮厚度、厚度變化及肌肉筋膜交點的滑動在兩側皆有顯著有進步(p<0.001)。下背痛的病人的前後肌肉肌膜交點在放鬆後皆往前側(腹側)移動(p<0.001)；兩組肌肉長度無論放鬆前後皆無變化(p=0.09)。比較不同位置下的量測，前側的滑動及肌肉厚度變化皆較後側量測值大。 結論：量測後側的腹橫肌提供了肌肉起始位置的資訊，發現了下背痛的受試者中，放鬆後的腰帶系統呈現往前側移動的情形，但無肌肉長度的變化。表示下背痛受試者的腹橫肌於放鬆前應處於較後側的位置上,且效果的並非來自於肌肉長度的改變。一端點的放鬆能影響整個腰帶系統的表現，使系統的張力達到新的平衡，使腹橫肌前後側的測量參數都有進步的表現，支持了肌肉肌膜張力重新分布的概念。臨床上可將張力平衡概念應用於肌肉骨骼系統，以調整改善局部張力的方式進行整體的評估及治療，提供另一個臨床思考的方向。

Background: The transversus abdominis (TrA) is the deepest abdominal muscle which is proposed to contribute to lumbar stability. The TrA connected to the lumbar spine via thoracolumbar fascia (TLF) and forms a musculofascial corset to modulate intra-abdominal pressure and control segmental movement of the spine. Subjects with chronic low back pain demonstrated a deficit in the performance of the TrA. Previous studies focus on measuring sliding of the anterior muscle-fascia junction but ignoring the integrity of the corset system. Purposes: The purposes of this study are (1) to establish the intra-rater reliability of measuring the sliding of posterior muscle-fascia junction of the TrA; (2) to investigate the relationship between the anterior and posterior sites of the TrA in the muscle thickness and sliding of muscle-fascia junctions; (3)to compare the sliding of two muscle-fascia junctions (ΔX), change in thickness (ΔT) and length (ΔL) of the TrA in subjects with or without LBP; (4) to evaluate the immediate effect of manual release on the sliding of muscle-fascia junctions, the change in thickness, muscle length and pattern of displacement of muscle-fascia junctions of the TrA. Methods: Ten participants without LBP were included in the reliability study. Forty subjects with or without chronic LBP were included. The real-time US viewed in B-mode with 5-12 MHz linear transducer was used. Participants were positioned in hook-lying to perform abdominal drawing-in maneuver (ADIM). The outcome variables included the resting thickness (Thr), the thickness during contraction (Thc), ΔT, ΔX, ΔL and displacement pattern (ΔD) of the TrA at anterior and posterior muscle-fascia junctions. Myofascial release was applied at the middle point of TLF for one minute. The reliability was analyzed using Intra-class correlation coefficient (ICC). The relationship between the US measurements of the anterior and posterior muscle-fascia junctions of the TrA were analyzed with Pearson correlation. Between participants with and without LBP, three-way analysis of variance (3-way ANOVA) was used to analyze the Thr, Thc, ΔT, ΔX, between the anterior and posterior regions before and after release of the TLF. Two-way ANOVA was used to analysis the ΔL and ΔD before and after release between two groups. The α-value is set at 0.05. Results: Measuring the thickness and sliding of muscle-fascia junction of posterior site of the TrA showed good reliability (ICC(3,3)=0.888-0.978). The correlation between the measurements between the anterior and posterior sites of the TrA were moderate to good (Pearson correlation (r)=0.41-0.74). Comparing between groups, participants with LBP revealed less thickness during contraction, change in thickness and sliding of muscle-fascia junctions at both sites (p<0.005). After myofascial release, both groups improved the change in thickness and sliding of muscle-fascia junctions at both sites (p<0.001).The LBP group demonstrated an anterior-shift pattern of the muscle-fascia junctions at both end (p<0.001). The muscle length were not statistical different after release in both groups (p=0.09). The measurements at posterior site were all smaller than the anterior site. Conclusion: Both groups improved after myofascial release, the result supported the tensegrity concept that the imbalanced tension could be adjusted from remote site. Furthermore, measuring the resting location at both site provide the evidence that the anterior-shift pattern of the musculofascial corset system in LBP group is not due to change in muscle length. Treating patients with musculoskeletal problems may need a comprehensive evaluation of the whole body, to identify the imbalance of the tension, therefore may provide an optimal treatment for patients with musculoskeletal problems.