單側下背痛病人於腹橫肌收縮時外側縫之剛性增加

Abstract

背景: 肌筋膜提供身體跨關節的肌群連續之整體性，且對所相連之肌肉骨骼有張力調節的作用，肌肉-筋膜變化存在於下背痛病人中。胸腰筋膜中的外側縫為側腹三層肌肉-筋膜與豎脊肌群之集合處，過去的研究中已探討超音波影像量測下背痛患者腹橫肌的收縮表現較正常人差，且發現筋膜型態為厚度增加與腹橫肌肌筋膜滑動減少，然而腹橫肌收縮時的筋膜張力如何傳遞仍沒有研究探討，力的傳遞在肌肉骨骼系統將影響組織受力與受傷程度。近年運用彈性造影超音波量測筋膜剛性，可反映筋膜受力後機械特性改變，然而彈性造影超音波量測筋膜剛性之信度仍未建立。筋膜剛性在無症狀者及單側下背痛病人於腹橫肌收縮時是否增加、是否對稱，及兩組之差異亦未知。 目的: 本實驗目的為: (1) 建立彈性造影超音波在休息與腹橫肌收縮狀態時外側縫剛性之信度; (2) 比較無症狀者於不同狀態之差異與左右兩側外側縫剛性的對稱性; (3) 比較單側下背痛者於不同狀態之差異與痛側/非痛側外側縫剛性的對稱性; (4) 比較兩組於休息與腹橫肌收縮狀態下之外側縫剛性差異。 方法:信度實驗收取14位無症狀者(22.4±2.8歲)。主要實驗收取42位，包含20位無症狀者(26.5±4.1歲)及22位單側下背痛患者(29.7±6.7歲)。受試者於趴姿下做腹部內收(腹橫肌收縮)，測試者以彈性超音波(SuperSonic Imagine, Aix en Provence, France)量取外側縫剛性，測量參數包含身體兩側休息及收縮狀態時的剛性。信度實驗以組內相關係數(ICC(3,3))分析；組內間之狀態差異與兩側對稱性以混和設計變異數分析檢定；以二因子混合共變數分析比較於不同狀態時，兩組外側縫剛性之差異，α值設在0.05。 結果: 以彈性造影超音波量測無症狀者之外側縫剛性呈現良好信度(ICC(3,3) =0.77-0.96)；不同分析者之影像間信度為0.85-0.88(ICC(3,1))。信度受試者之兩側與狀態交互作用不顯著，兩側無差異(左:17.18±9.47kPa；右:19.73±8.42kPa, p=0.427)，不同狀態下也無差異(休息:18.51±7.70kPa；收縮:18.40±10.18kPa, p=0.939)。背痛組之兩側與狀態交互作用不顯著，兩側無差異(痛側:22.30±10.05 kPa；非痛側:22.69±8.99 kPa, p=0.879)，但不同狀態下有差異(休息: 19.48±7.61 kPa；收縮:25.51±10.95kPa, p<0.00008)。主要實驗受試者之組別與狀態交互作用顯著(F=15.762，p=<0.0005)，組別因子之事後分析為腹橫肌收縮時，背痛組之外側縫剛性較無症狀者大 (下背痛:26.12±12.87 kPa；無症狀:19.40±8.07 kPa, p=0.001)。 結論: 量測外側縫剛性提供了量化筋膜的方法，且信度良好。無症狀者腹橫肌收縮時外側縫剛性與休息時相比不變且兩側外側縫剛性對稱。單側下背痛者腹橫肌收縮時外側縫剛性比休息時大。疼痛側及非疼痛側間剛性無差異。下背痛組之外側縫剛性於腹橫肌收縮時，較無症狀組大。本實驗探討於動態收縮下之筋膜機械特性改變，支持下背痛病人肌肉筋膜張力動態失衡之現象。

Background: Myo-fascia provides a continuous network of restricting but adjustable tension around muscles and bones. Muscle-fascia tenderness is noted in patients with low back pain (LBP). The lateral raphe (LR), part of thoracolumbar fascia, is the junction connecting lateral abdominal muscles and paraspinal muscles. Participants with LBP demonstrate a morphological deficit during the contraction of the transverse abdominals, which is termed abdominal draw-in maneuver (ADIM), decreased change of muscle thickness and muscle-fascia sliding, as well as increased fascia thickness. However, the investigation is few in tension transmission during contraction, which is an important issue related to tissue loading and lesion in musculoskeletal systems. The technology of shear wave elastography (SWE) could provide the measurement of the stiffness of soft tissue through the calculation of young's module. However, the reliability of fascia stiffness measured by SWE is unknown. Whether the fascia stiffness is symmetry in sides, increased during ADIM in asymptomatic participants and patients with unilateral LBP is unknown, neither the difference between groups. Purposes: The purposes of this study were (1) to establish the intra-rater reliability of LR stiffness under resting and ADIM conditions by using SWE, (2) to compare the differences of LR stiffness under these conditions and between sides in asymptomatic participants, (3) to compare the LR stiffness under resting and ADIM conditions, and between painful and non-painful sides in participants with unilateral LBP, and (4) to compare the LR stiffness under resting and ADIM conditions between asymptomatic participants and patients with unilateral LBP. Method: 14 asymptomatic participants (22.4±2.8 y/o) were included in the reliability study. Patients with unilateral LBP (n=22, 29.7±6.7 y/o) and asymptomatic participants (n=20, 26.5±4.1 y/o) were recruited in the main study. The SWE (SuperSonic Imagine, Aix en Provence, France) with 5-12MHz linear transducer was used to measure the stiffness of LR. Participants were positioned in prone and asked to perform ADIM. The outcome variables included the LR stiffness of bilateral sides in resting and ADIM condition. The reliability was analyzed using intra-class correlation coefficient (ICC(3,3)). Two-way repeated ANOVA was used to analysis the stiffness of LR between bilateral sides and in resting and ADIM condition. Two-way repeated measures ANCOVA was used to analysis the difference of LR stiffness between asymptomatic participants and patients with unilateral LBP in resting and ADIM condition. Result: The intra-rater reliability of measuring the LR stiffness in resting and ADIM condition was in the range of good to excellent (ICC(3,3)=0.77-0.96); the reliability of measuring the same images by different raters were 0.85-0.88(ICC(3,1)). In participants enrolled in reliability study, no interaction between sides and conditions. The main effect of sides (left: 17.18±9.47 kPa; right: 19.73±8.42 kPa, p=0.427) and conditions (resting: 18.51±7.70 kPa; ADIM: 18.40±10.18 kPa, p=0.939) was not significant. No interaction between sides and conditions in LBP group. The main effect of sides was not significant (painful: 22.30±10.05 kPa; non-painful: 22.69±8.99 kPa, p=0.879), yet, the main effect of conditions was significant (resting: 19.48±7.61 kPa; ADIM: 25.51±10.95 kPa, p<0.00008). There was significant interaction between groups and conditions (F=15.762，p=<0.0005). Post hoc for group demonstrated that LR stiffness was greater in LBP group during ADIM (LBP: 26.12±12.87 kPa; asymptomatic: 19.40±8.07 kPa, p=0.001). Conclusion: Measuring the LR stiffness in resting and ADIM condition using SWE is reliable. The LR stiffness in asymptomatic participants was symmetrical. The LR stiffness between resting and ADIM condition was unchanged in asymptomatic group. Whereas the stiffness of both painful and non-painful sides in patients with unilateral LBP is increased during ADIM. Furthermore, LR stiffness in patients with unilateral LBP in resting was not different from asymptomatic group. The result of the present study investigating the fascia property in dynamic condition supports the concept of dynamic myo-fascial tension imbalance in patients with LBP.