岡下肌肌筋膜疼痛綜合征的特點(diǎn)
王娟 譯
目的
探討岡下肌MTrP的特點(diǎn),，評(píng)估MTrP注射的治療效果。
方法
本研究對(duì)297名患者（221名女性,；年齡,，53.9 /-11.3歲）的岡下肌MTrP的醫(yī)療記錄進(jìn)行回顧分析。 對(duì)總共380例岡下肌存在MTrP的病人都進(jìn)行了研究（214例在單側(cè),，83例雙側(cè)都有）,。收集的具體特征包括主訴區(qū)、牽涉痛模式,、局部抽搐反應(yīng)的數(shù)量和肌肉中MTrP的分布,。統(tǒng)計(jì)分析用配對(duì)t檢驗(yàn)比較第一次注射前和注射后兩周的視覺模擬量表。
結(jié)果
岡下肌上的MTrP最常見出現(xiàn)在肩胛區(qū),。牽涉痛最常見的地方是手臂的前外側(cè)（肘部上方）,。岡下肌中活化的MTrP多見多個(gè)出現(xiàn),，單一的比較少見,，并且經(jīng)常出現(xiàn)在肌肉的中心,。
在岡下肌MTrP注射可以顯著地降低疼痛強(qiáng)度,。與基線相比,，第一次注射后視覺模擬量表評(píng)分明顯下降（7.11與3.74；p＜0.001）。
結(jié)論
評(píng)估MTrP的特點(diǎn)及注射療效,。這些發(fā)現(xiàn)可以為臨床醫(yī)生診斷和治療岡下肌肌筋膜疼痛綜合征提供有用的信息,。
關(guān)鍵詞
岡下肌，肌筋膜疼痛綜合征，MTrP，疼痛,，注射
介紹
肩胛骨附近的非特異性的疼痛非常常見,，可能是由頸椎或肩關(guān)節(jié)紊亂引起的。但是有時(shí)候肩胛骨附近的疼痛似乎與頸椎或肩關(guān)節(jié)沒有任何關(guān)系,，這時(shí)候就需要用臨床研究來揭示可能的疼痛原因并找到有效的治療方法。
激痛點(diǎn)(MTrPs)可以為肩胛疼痛的病理生理機(jī)制提供另一種解釋,。雖然激痛點(diǎn)很少是疼痛的主要來源[1,2],，但有證據(jù)表明激痛點(diǎn)是由另一種軟組織的病變引起的或與之有關(guān),，如脊柱紊亂或肩袖疾病[2,3],。激痛點(diǎn)是對(duì)壓力高度敏感的局部點(diǎn)。
激痛點(diǎn)的觸診可以產(chǎn)生疼痛,、肌肉功能紊亂和交感亢進(jìn)等相關(guān)特征。激痛點(diǎn)分為活化的和失活的兩種。活化的激痛點(diǎn)表現(xiàn)為臨床疼痛,，伴有或不伴有緊繃帶的壓痛，而失活的激痛點(diǎn)在臨床上是不活動(dòng)的,，只有在觸診時(shí)才會(huì)疼痛,。
根據(jù)我們的臨床經(jīng)驗(yàn),，許多有脊椎或肩袖疾病或者沒有這些疾病的患者也有岡下肌產(chǎn)生的肩胛痛,。岡下肌是一種厚三角肌，占據(jù)了下凹窩的主要部分,，并協(xié)助手臂的外旋和肱骨在手臂運(yùn)動(dòng)時(shí)的穩(wěn)定[7],。這塊肌肉中活化的激痛點(diǎn)會(huì)引起局部和肩區(qū)相關(guān)疼痛，并向下到手臂的前面和外側(cè)[5],。
岡下肌上經(jīng)常出現(xiàn)激痛點(diǎn),。在一項(xiàng)對(duì)126名患者進(jìn)行的研究中，在31%的病例中,，肩胛下肌引起相關(guān)肩區(qū)疼痛的頻率僅次于肩胛提肌(55%)[8],。另一項(xiàng)研究也報(bào)告了類似的結(jié)果[9],。在年輕,、無疼痛的成人中，岡下肌是緊隨肩胛提肌(20%)和上斜方肌(35%)[10]的第三大廣泛存在失活激痛點(diǎn)的肌肉(18%),，,。
通過詳細(xì)的病史和體格檢查評(píng)估，我們最近觀察到許多患者符合在岡下肌中存在激痛點(diǎn)的標(biāo)準(zhǔn),。在治療這些病人的過程中,，我們發(fā)現(xiàn)了一些與之前的研究[11]的差異：主訴區(qū)域，牽涉痛模式,，激痛點(diǎn)的分布,，以及觸發(fā)點(diǎn)注射的治療效果。本研究的目的是報(bào)告岡下肌上的激痛點(diǎn)的特點(diǎn),。
材料和方法
參與者
在機(jī)構(gòu)審查委員會(huì)批準(zhǔn)后,，我們回顧分析了在2013年3月至2015年11月期間訪問西富蘭斯醫(yī)院門診部的446名疑似岡下肌上存在激痛點(diǎn)的患者的醫(yī)療記錄，以確定所有符合條件的病人(4 -2015- 1049),。診斷活化的激痛點(diǎn)是根據(jù)之前的標(biāo)準(zhǔn),包括岡下肌的痛處,，按壓痛處引起相應(yīng)疼痛的兼容模式,限制范圍的肩膀的運(yùn)動(dòng)，和在緊繃的最敏感的地方明顯的或可見的局部抽搐反應(yīng)(LTRs),。在觸發(fā)點(diǎn)注射過程中,，LTRs被誘導(dǎo)和評(píng)估。由于針刺在識(shí)別LTRs時(shí)比手動(dòng)觸診更加敏感,，因此選擇針刺方法來確認(rèn)激痛點(diǎn)的存在,。
在岡下肌有激痛點(diǎn)的患者中，符合下列標(biāo)準(zhǔn)的包括:肌肉和筋膜的激痛點(diǎn),，獨(dú)有的肌腱病;在0-10的數(shù)值范圍的視覺模擬量表(血管)測(cè)量的疼痛分?jǐn)?shù)大于2(≥3);并且有一個(gè)觸發(fā)點(diǎn)注射,。排除有以下情況的患者:(1)在干預(yù)前2周接受治療,，并通過隨訪期，有可能影響到結(jié)果(如止痛藥,、物理治療或其他注射治療);(2)存在一些其他可能出現(xiàn)相同癥狀的全身疾病(如:纖維肌痛);(3)有神經(jīng)學(xué)肩/肩胛痛(如:,，頸椎病或周圍神經(jīng)損傷;(4)既往使用過利多卡因或類固醇，或者在注射過程中可能使病人有重大風(fēng)險(xiǎn)的狀況或情況,。
然而,，如果患者符合在岡下肌有激痛點(diǎn)的標(biāo)準(zhǔn)，即使他們有肩袖和/或頸椎疾病的病史,，也不會(huì)被排除在外,。岡下肌筋膜疼痛綜合征的特點(diǎn)。
MTrP注射
所有注射均在超聲(US)引導(dǎo)下進(jìn)行,。然而,，這項(xiàng)研究的回顧性設(shè)計(jì)并不是評(píng)估超聲指導(dǎo)下的岡下肌注射的有用性?？紤]到本研究的岡下肌的激痛點(diǎn),，我們對(duì)先前報(bào)告的超聲指導(dǎo)的下背部肌肉、深骨盆肌肉和臂肌觸發(fā)點(diǎn)注射方法進(jìn)行了改良(12 - 14),。我們使用一臺(tái)Accuvix V10 超聲機(jī)器(麥迪遜,首爾,韓國(guó))在無菌環(huán)境,、目標(biāo)肌肉周圍的一個(gè)5到12 mhz的線性陣列傳感器上進(jìn)行了b模式的實(shí)時(shí)超聲。一名有8年以上肌肉骨骼超聲經(jīng)驗(yàn)的物理治療師執(zhí)行了所有超聲指導(dǎo)的注射手術(shù),。
病人俯臥于檢查床,患臂做延伸,、內(nèi)旋、內(nèi)收動(dòng)作并盡力夠到胸椎,也就是在類似于手術(shù)“折臂固定”的位置進(jìn)行注射手術(shù)(圖1),。這個(gè)位置,我們可以通過分離肩胛骨周圍組織簡(jiǎn)單而又安全地到達(dá)岡下肌,。
我們通過對(duì)肌群的超聲掃描將三角肌、斜方肌,、大圓肌,、小圓肌、背闊肌和岡下肌區(qū)分開來,，并通過觸診肌肉在皮膚上標(biāo)記壓痛點(diǎn),。通過對(duì)標(biāo)記點(diǎn)的探頭定位，將探頭轉(zhuǎn)向最佳視角,，可以看到目標(biāo)區(qū)域的圖像(圖1,、2)。使用彩色多普勒?qǐng)D像來避開神經(jīng)血管束,。在超聲指導(dǎo)下連接一根25尺,、2.6厘米的針頭與一個(gè)含有4毫升0.5%利多卡因與1毫升40毫克去炎松的5毫升注射器，在觸到壓痛點(diǎn)的岡下肌上進(jìn)行注射,。在一個(gè)肌肉有多個(gè)壓痛點(diǎn)的情況時(shí),，所有的壓痛點(diǎn)都要重復(fù)注射,。
在每次治療期間，注射部位的順序都是根據(jù)觸診壓痛點(diǎn)時(shí)疼痛嚴(yán)重程度的下降順序確定的,。每個(gè)壓痛點(diǎn)的注射量為0.5 mL,，如果準(zhǔn)備好的5毫升溶液全部用完(最多每次治療10個(gè)注射點(diǎn))或觸診沒有發(fā)現(xiàn)有壓痛點(diǎn)，就不再進(jìn)行注射,。利用離面法,，我們可以看到針穿過皮膚和脂肪組織進(jìn)入肌肉。物理治療師超聲下觀察LTRs并進(jìn)行觸發(fā)點(diǎn)注射,。重復(fù)針刺來引出盡可能多的LTRs,。如果嘗試10次后沒有觀察到LTR，就停止針刺,，并注射混合溶液,。按壓注射部位以確保術(shù)后止血。所有肌肉的觸發(fā)點(diǎn)注射都在2周的間隔內(nèi)進(jìn)行,。如果病人對(duì)減少不適或疼痛程度的效果感到滿意,，或者不想再次注射，則不考慮額外注射,。教導(dǎo)病人做拉伸運(yùn)動(dòng)(每天重復(fù)10到20次),，避免任何可能會(huì)加重癥狀的不良姿勢(shì),。
數(shù)據(jù)收集
收集年齡,、性別、患側(cè)及癥狀持續(xù)時(shí)間等人口統(tǒng)計(jì)學(xué)和臨床數(shù)據(jù),。記錄疼痛強(qiáng)度,、癥狀持續(xù)時(shí)間、主訴區(qū),、牽涉痛模式,、注射次數(shù)、LTRs的數(shù)量,，肌肉上激痛點(diǎn)的分布建立在超聲指導(dǎo)下注射的LTRs那側(cè)(圖3),。
疼痛強(qiáng)度用10厘米水平的從0(沒有疼痛)到10(最難以想象的疼痛)視覺模擬評(píng)分法測(cè)量。在每次注射的基線和2周后用視覺模擬評(píng)分法進(jìn)行評(píng)估,。
系統(tǒng)分析
我們對(duì)病人信息和岡下肌上激痛點(diǎn)的特點(diǎn)進(jìn)行了描述性分析,。
對(duì)于雙側(cè)岡下肌均存在激痛點(diǎn)的患者，每一側(cè)的疼痛強(qiáng)度,，癥狀持續(xù)時(shí)間,，主訴區(qū)域，牽涉痛模式,，注射次數(shù),，以及LTRs的數(shù)量都進(jìn)行了評(píng)估,。觸發(fā)點(diǎn)注射效果的評(píng)估使用了在基線和第一次注射的2周后獲得的視覺評(píng)分模擬數(shù)據(jù)的夏皮羅-威爾克檢驗(yàn)，以查明該分布是否正常,。使用夏皮羅-威爾克檢驗(yàn)顯示這些參數(shù)的正態(tài)分布的同時(shí),，采用配對(duì)t 檢驗(yàn)來比較第一次觸發(fā)點(diǎn)注射前與注射兩周后的參數(shù)。統(tǒng)計(jì)學(xué)意義為p值< 0.05,。SPSS版本21.0軟件(IBM,Armonk,NY,USA)用于所有統(tǒng)計(jì)分析,。
結(jié)果
在2013年3月至2015年11月期間，我們回顧了446例疑似岡下肌上有激痛點(diǎn)的患者的醫(yī)療記錄,。其中297名患者(221名女性和76名男性)符合參加這項(xiàng)研究的條件,。
因?yàn)橛?3例患者在雙側(cè)岡下肌中存在激痛點(diǎn)，有380例岡上肌存在激痛點(diǎn)的符合納入標(biāo)準(zhǔn),。
在83例雙側(cè)岡下肌存在激痛點(diǎn)的患者中,，雙側(cè)肌肉都在持續(xù)時(shí)間、疼痛嚴(yán)重程度,、主訴區(qū)域和牽涉痛模式上分別進(jìn)行評(píng)估,。表1總結(jié)了297例患者的人口統(tǒng)計(jì)學(xué)和臨床數(shù)據(jù)，并總結(jié)了380例有激痛點(diǎn)的岡下肌的臨床特征,。
297名患者中有103名患者有肩部疾病的病史,，包括肩袖疾病(n = 103,34.7%)，運(yùn)動(dòng)傷或工傷而沒有肩部和勁椎疾病(n = 89,30.3%),，頸椎疾病(n = 61,20.5%),，肩病合并頸椎病(n = 44,14.8%)。在工傷患者中,，我們發(fā)現(xiàn)17人(5.7%)在照顧孩子,。
在380例岡下肌存在激痛點(diǎn)患者中，最常見的主訴區(qū)域?yàn)榧珉螀^(qū);其次是在肩膀的前面深處(表1),。有一百三十一例病人提到除了主要的主訴區(qū)域外的疼痛;最常見的區(qū)域是手臂的前外側(cè)(肘部上方)(表2).
根據(jù)所有380例岡下肌確定了對(duì)診斷激痛點(diǎn)必須的LTRs ,。然而，在醫(yī)學(xué)圖表中,，LTRs的數(shù)量只有153例,。其中38例(24.8%)少于5個(gè)LTRs。6 - 10,、11 - 15,、16 - 20和> 10 LTRs分 別為45(29.4%)、46(30.1%),、24(15.7%)和70(45.8%),。
圖3總結(jié)了297例患者肩胛骨下肌筋膜的分布情況。在一共380例患者中,，發(fā)現(xiàn)了1468個(gè)激痛點(diǎn),，平均每塊肌肉有4.9個(gè)激痛點(diǎn),。
在380例病例中，對(duì)135例進(jìn)行了觸發(fā)點(diǎn)注射的治療,。這135例患者,，有16例(11.9%)注射1針，2周內(nèi)注射2次,，88例(65.2%),，31例患者每2周注射3例(23.0%)。與基線相比,，第一次注射后兩周VAS有明顯的下降(p < 0.001),。在第一次治療后，平均值從7.11(SD = 1.45)預(yù)處理到3.74(SD = 1.53),。
討論
這項(xiàng)研究有三個(gè)重要的發(fā)現(xiàn),。首先，岡下肌激痛點(diǎn)的主要癥狀之一是產(chǎn)生肩胛骨疼痛,。第二,，活化的激痛點(diǎn)幾乎總是多個(gè)出現(xiàn)的，而非在患側(cè)岡下肌單獨(dú)出現(xiàn),。第三,，岡下肌的活化激痛點(diǎn)的失活會(huì)明顯降低疼痛強(qiáng)度。
在早期的研究[9,15 - 18]中,，岡下肌激痛點(diǎn)的主要癥狀是在肩前深部的疼痛,，包括前三角肌區(qū)。雖然激痛點(diǎn)的疼痛經(jīng)常發(fā)生在肩前的深部,，但在這項(xiàng)研究中肩關(guān)節(jié)部位的疼痛更加普遍,。這些發(fā)現(xiàn)可能取決于激痛點(diǎn)定義的差別,，病人的數(shù)量,，以及在體檢中詢問病人的問題的正確性。
首先,，激痛點(diǎn)可以存在于骨骼肌組織,，肌肉的腱膜(筋膜)，或肌腱,，但這項(xiàng)研究?jī)H限于岡下肌組織和/或肌筋膜內(nèi)的激痛點(diǎn),，即最普遍形式的激痛點(diǎn)[19]。
其次,，我們并沒有排除那些符合岡下肌存在激痛點(diǎn)的標(biāo)準(zhǔn)但有頸椎病史或肩損傷病史的患者,。第三，由于患者可能不能區(qū)分肩胛骨疼痛和肩痛,，理療師在體檢時(shí)提出了一些問題,，來確認(rèn)疼痛是出現(xiàn)在肩胛骨區(qū)域,。如果理療師并沒有特別詢問肩胛疼痛，病人就可能會(huì)認(rèn)為這個(gè)問題是關(guān)于肩痛的,。
牽涉痛是一種疼痛感,，并不是真正的原發(fā)部位[20]。在本研究中,，來自岡下肌的激痛點(diǎn)所提到的疼痛位置在頻率上依次是手臂的前外側(cè)(肘部以上),，外側(cè)前臂，上后頸,，和手的放射狀區(qū)域(包括一個(gè)手指),。我們的結(jié)果與對(duì)193例患者的研究結(jié)果相似，其中手臂的前外側(cè)部分(46%)是最常出現(xiàn)的疼痛部位,，其次是前臂外側(cè)(21%),，后頸(14%)，手的橈側(cè)(13%)[9,11,15,16,18,21,22],。如果牽涉痛在手部的放射狀區(qū)域時(shí),，將其區(qū)別于頸椎病尤為重要，主要是C5或C6級(jí)[23],。
牽涉痛的范圍和部位取決于岡下肌激痛點(diǎn)的位置和強(qiáng)度,，以及需要進(jìn)一步的研究。岡下肌和小圓肌的激痛點(diǎn)經(jīng)常會(huì)一起出現(xiàn),，而且經(jīng)常被錯(cuò)誤地評(píng)估為肩袖損傷或頸椎間盤源性疼痛,。另外，岡下肌的激痛點(diǎn)經(jīng)常被錯(cuò)誤地評(píng)估為肩關(guān)節(jié)炎,，肩胛上神經(jīng)的壓迫或者肱二頭肌肌腱炎[19],。還有，岡下肌激痛點(diǎn)應(yīng)與大圓肌,、岡上肌,、、前三角肌,、肩胛下肌和胸肌[19]區(qū)別開來,。
這項(xiàng)研究的主要貢獻(xiàn)之一是發(fā)現(xiàn)了在疼痛側(cè)的岡上肌上有多個(gè)活化的激痛點(diǎn)，而不僅僅是單個(gè),。此外,，每塊岡下肌上有多個(gè)LTRs，我們已經(jīng)觀測(cè)到很多有十多個(gè)LTRs的例子(45.8%),。如果在注射過程中誘導(dǎo)出LTRs,，尤其使用快進(jìn)快出手法后，疼痛經(jīng)常可以得到迅速的緩解[24,25],。反之如果在觸發(fā)點(diǎn)注射時(shí)沒有引起LTRs,，病人就不能體驗(yàn)到迅速完全的疼痛緩解。
注射了一個(gè)反應(yīng)點(diǎn)后,，其他的LTRs可以被激發(fā)出來,。重復(fù)這些步驟，直到所有(或盡可能多)反應(yīng)點(diǎn)被注入[26],。據(jù)我們所知,，LTRs的數(shù)量之前沒有報(bào)告過。因此,，這些結(jié)果強(qiáng)調(diào)了在岡下肌肌筋膜疼痛綜合征患者的一塊肌肉中尋找多個(gè)活化的激痛點(diǎn)區(qū)域和LTRs的重要性,。在同一塊肌肉中的多個(gè)激痛點(diǎn)每一個(gè)都可能導(dǎo)致整體的牽涉痛模式。
岡下肌的觸發(fā)點(diǎn)注射治療效果非常好,，并且治療后VAS評(píng)分也降低了,。我們建議，對(duì)于岡下肌上有激痛點(diǎn)的病人,，如果懷疑他的肩胛骨疼痛是由岡下肌引起的,，對(duì)其進(jìn)行岡下肌觸發(fā)點(diǎn)的注射則對(duì)于診斷和治療都會(huì)有效。
岡下肌的激痛點(diǎn)通常是由急性壓力或多次負(fù)荷過多的壓力激活的,。這些激痛點(diǎn)可能會(huì)在特定的持續(xù)因素的影響下變得活化然后誘發(fā)疼痛,，例如重復(fù)性和持續(xù)的肩部活動(dòng)[27,28]。這可能是那17名沒有肩膀損傷但是照顧孩子的病人患病的原因,。當(dāng)肩膀外展和彎曲時(shí),，岡下肌顯示的活動(dòng)比岡上肌的少[29]。然而,，在外展超過140°以后岡下肌活動(dòng)顯著增加,。因此，當(dāng)病人長(zhǎng)時(shí)間肩帶超過肩峰水平的負(fù)重時(shí),，,，就會(huì)損傷岡下肌。這些機(jī)制可以解釋那些沒有潛在疾病但是經(jīng)常參與照顧孩子的婦女案例,。不同于岡上肌,，岡下肌更容易在不尋常和短暫的運(yùn)動(dòng)中被激活，而且急性負(fù)荷可能比持續(xù)負(fù)荷的任務(wù)更容易產(chǎn)生激痛點(diǎn)[11],。
肌肉的不平衡也會(huì)使激痛點(diǎn)活躍,并引起復(fù)發(fā)性疼痛。既然激痛點(diǎn)可以誘導(dǎo)正常的肌肉活化模式和后續(xù)的運(yùn)動(dòng)功能障礙的改變,，那么識(shí)別和滅活激痛點(diǎn)應(yīng)該能夠改善運(yùn)動(dòng)功能,緩解肌肉僵硬,恢復(fù)肩部的正常生物力學(xué)[30],。
了解在岡下肌中激痛點(diǎn)的常見部位很重要，以便為這塊肌肉的激痛點(diǎn)的臨床識(shí)別提供指導(dǎo)。仔細(xì)觸診可以容易發(fā)現(xiàn)岡下肌的多個(gè)痛點(diǎn),，也被認(rèn)為是多個(gè)病變,。在以往的研究中，最常見的激痛點(diǎn)區(qū)域是在肩胛骨脊柱緣最內(nèi)側(cè)和鄰近區(qū)域四分之一長(zhǎng)的交界處(上內(nèi)側(cè)病變)[11],。第二個(gè)最常見的激痛點(diǎn)區(qū)域?yàn)榧珉喂羌怪壷悬c(diǎn)尾部[11],。在本研究中，常見的激痛點(diǎn)區(qū)域與Travel發(fā)現(xiàn)的相似,，但定位更廣泛,，且肩胛骨的下角更為常見。因?yàn)樵隗w檢過程中,，岡下肌面積廣泛,，全部觸診可能會(huì)很耗時(shí)，本研究可以為識(shí)別岡下肌的激痛點(diǎn)提供有用的指導(dǎo),。
超聲指導(dǎo)注射對(duì)檢測(cè)肌肉中位置深的LTRs和在注射時(shí)對(duì)更不容易接觸的肌肉深度進(jìn)行控制很有用,。超聲指導(dǎo)也可以減少因針頭放置不當(dāng)造成的意外傷害。但在岡下肌觸發(fā)點(diǎn)注射時(shí)沒有必要使用超聲引導(dǎo),，因?yàn)閷录∥恢帽頊\,，而且針頭不太可能在不經(jīng)意間傷害周圍的組織，比如肺,。然而,，通過使用超聲引導(dǎo)的注射，我們可以觀察到更多的LTRs來提高注射的效果并且區(qū)分鄰近的大圓肌,三角肌和斜方肌,，以便更準(zhǔn)確地診斷,，并通過記錄內(nèi)置視頻來提供治療反饋。這些優(yōu)勢(shì)可能值得關(guān)注,。
我們的研究有一些局限性,。首先，因?yàn)檫@項(xiàng)研究是回顧性的,，我們可能錯(cuò)過準(zhǔn)確分析所需的信息,。
其次，我們總結(jié)的觸發(fā)點(diǎn)注射的療效沒有對(duì)照組比較,。不過,，在短期治療中，我們不能忽視視覺評(píng)分模擬量表注射量的顯著減少(超過3分),。
第三,，每個(gè)案例我們只研究了一種牽涉痛模式。如果存在多個(gè)痛點(diǎn),，則可能會(huì)有許多不同的疼痛模式,，這些都取決于痛點(diǎn)的位置、數(shù)目和疼痛的嚴(yán)重程度。這也是一個(gè)回顧性研究的局限性,，可以通過進(jìn)一步的前瞻性研究來補(bǔ)充,。
第四，觸發(fā)點(diǎn)注射治療效果的隨訪時(shí)間相對(duì)較短,。雖然沒有長(zhǎng)期隨訪,，但對(duì)岡下肌內(nèi)激痛點(diǎn)的觸發(fā)點(diǎn)注射的長(zhǎng)期效果與其他肌肉并不會(huì)有什么區(qū)別。如果不能消除潛在的病原病灶,，一個(gè)觸發(fā)點(diǎn)注射的效果通常會(huì)持續(xù)2周[13],。然而，活化的激痛點(diǎn)的失活對(duì)某些情況是必要的,，包括出現(xiàn)嚴(yán)重的,、無法忍受的疼痛,、干擾功能活動(dòng)的疼痛和不適,，以及持續(xù)的疼痛和緊張。同樣的原理可以應(yīng)用于岡下肌,。
第五,，選擇組的患者不均勻。特別是一些有肩或頸椎損傷的患者參與了這項(xiàng)研究,。激痛點(diǎn)可繼發(fā)于病理狀態(tài),，如慢性重復(fù)小肌肉拉傷、不良坐姿,、全身疾病,、肌肉骨骼損傷(如應(yīng)變、扭傷,、神經(jīng)炎,、粘液囊炎、關(guān)節(jié)炎,、椎間盤損傷)[2,3],。但對(duì)于我們研究中有肩部或頸椎損傷病史的患者，其病變并不是其就診的主要原因,。此外，他們的癥狀符合了激痛點(diǎn)標(biāo)準(zhǔn),，具有諷刺意味的是,，他們的激痛點(diǎn)并不比沒有肩部或頸椎損傷病史的患者更少[1],。
綜上所述,，岡下肌激痛點(diǎn)的發(fā)現(xiàn)和觸發(fā)點(diǎn)注射的療效,，可以為臨床醫(yī)生診斷和治療岡下肌肌筋膜疼痛綜合征提供有用的信息,。
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原文鏈接：
http://www./journal/viewJournal.html?year=2017&vol=041&page=573
Characteristics of Myofascial Pain Syndrome
of the Infraspinatus Muscle
Objective
To report the characteristics of myofascial trigger points (MTrPs) in the infraspinatus muscle and evaluate the therapeutic effect of trigger-point injections.
Methods
Medical records of 297 patients (221 women; age, 53.9±11.3 years) with MTrPs in the infraspinatus muscle were reviewed retrospectively. Because there were 83 patients with MTrPs in both infraspinatus muscles, the characteristics of total 380 infraspinatus muscles with MTrPs (214 one side, 83 both sides) were investigated. Specific characteristics collected included chief complaint area, referred pain pattern, the number of local twitch responses, and distribution of MTrPs in the muscle. For statistical analysis, the paired t-test was used to compare a
visual analogue scale (VAS) before and 2 weeks after the first injection.
Results
The most common chief complaint area of MTrPs in the infraspinatus muscle was the scapular area. The most common pattern of referred pain was the anterolateral aspect of the arm (above the elbow). Active MTrPs were multiple rather than single in the infraspinatus muscle. MTrPs were frequently in the center of the muscle.
Trigger-point injection of the infraspinatus muscle significantly decreased the pain intensity. Mean VAS score decreased significantly after the first injection compared to the baseline (7.11 vs. 3.74; p<0.001).
Conclusion
Characteristics of MTrPs and the therapeutic effects of trigger-point injections of the infraspinatus muscle were assessed. These findings could provide clinicians with useful information in diagnosing and treating myofascial pain syndrome of the infraspinatus muscle.
Keywords
Infraspinatus, Myofascial pain syndromes, Trigger points, Pain, Injections
INTRODUCTION
Nonspecific complaints of pain near the scapula are commonly encountered, and may originate from any disorder of the cervical spine or shoulder joint. In some cases, however, pain near the scapula appears without any relation to the cervical spine or shoulder, and additional clinical studies are required to reveal possible causes of pain and to find the effective treatments.
Myofascial trigger points (MTrPs) may offer an alternative explanation for the pathophysiological mechanism of scapular pain. Although MTrPs are rarely a primary origin of pain [1,2], evidence suggests that MTrPs are caused by or related to a lesion in another soft tissue, such as spine disorder or rotator cuff disease [2,3]. MTrPs are local points that are highly sensitive to pressure.
Their palpation causes characteristic referred sensations, including pain, muscle dysfunction, and sympathetic hyperactivity [4-6]. MTrPs are classified into active and latent. Active MTrPs present clinical pain with or without activity associated with tenderness in a taut band, whereas latent MTrPs are clinically quiescent and are painful only when palpated.
Based on our clinical experiences, many patients with or without spine or rotator cuff diseases also have scapular pains that originate in the infraspinatus muscle. The infraspinatus muscle, a thick and triangular muscle, occupies the chief part of the infraspinatus fossa and assists external rotation of the arm and stabilization of the humerus head during an arm movement [7]. Active MTrPs in this muscle cause both local pain and referred pain in the shoulder region and down to the frontal and lateral side of the arm [5].
The infraspinatus muscle frequently harbors MTrPs. In one study with 126 patients, referred pain to the shoulder region arose from the infraspinatus muscle in 31% of the cases, a frequency second only to that of the levator scapulae (55%) [8]. Another study reported similar results [9]. Among young, pain-free adults, the infraspinatus muscle was the third (18%) in the prevalence of latent MTrPs, following the levator scapulae (20%) and the upper trapezius (35%) [10].
We recently observed many patients who were compatible with the criteria of MTrPs in the infraspinatus muscle, as assessed by careful history taking and physical examination. In treating these patients, we found some differences from previous studies [11] in the chief complaint area, referred pain pattern, distribution of MTrPs, and therapeutic effect of trigger-point injection.The objectives of this study were to report on the characteristics of MTrPs in the infraspinatus muscle.
MATERIALS AND METHODS
Participants
After Institutional Review Board approval, we retrospectively reviewed the medical records of 446 patients with suspected MTrPs in the infraspinatus muscle who had visited the outpatient clinic of Severance Hospital between March 2013 and November 2015 in order to identify all eligible patients (4-2015-1049).Diagnosis of active MTrPs was based on prior criteria, including tender spots in the infraspinatus muscle, a compatible pattern of referred pain elicited when tender spots were compressed, restricted range of motion of the shoulder, and palpable or visible local twitch responses (LTRs) at the most sensitive spot in the taut band. LTRs were elicited and assessed during trigger-point injections. Since needling is more sensitive than manual palpation in identifying LTRs, the needling method was chosen to confirm the presence of MTrPs.
Among patients with MTrPs in the infraspinatus muscle, those who met the following criteria were included in this study: MTrPs of muscle and fascia, exclusive of enthesopathy; pain score measured by a visual analog scale (VAS) greater than 2 (≥3) on a numeric scale of 0?10; and
having a trigger-point injection. Patients were excluded if they had: (1) received treatment that could affect the result (such as pain killers, physical therapy, or other injection therapy) from 2 weeks before intervention and through the follow-up period; (2) some other systemic disease that could present the same symptom (e.g., fibromyalgia); (3) neurologic shoulder/scapular pain (e.g., cervical radiculopathy or peripheral nerve injury); and (4) previous history of an adverse effect of lidocaine or steroid, or any conditions or situations that might place the patient at significant risk during the injection.
However, if the patient met the criteria of MTrPs in the infraspinatus muscle, they were not excluded even if they had a history of the rotator cuff and/or cervical spine disease.Characteristics of Myofascial Pain Syndrome of the Infraspinatus Muscle.
Trigger-point injection
All injections were performed under ultrasound (US)-guided injection. However, this retrospective design of the sdeep pelvic muscles, and the brachialis muscles was modified for MTrPs in the infraspinatus muscles [12-14]. We performed B-mode, real-time US in a sterile environment using an Accuvix V10 US machine (Medison, Seoul, Korea) interfaced with a 5- to 12-MHz linear array transducer around the target muscle. A physiatrist with more than 8 years of experience in the musculoskeletal US carried out all the US-guided injection procedures.
The patients lay prone on an examination bed with the affected arm extended, internally rotated, and adducted, and try to reach the thoracic spine—that is, in a position similar to the surgical “chicken wing” position for injection procedures (Fig. 1). With this position, we could easily and safely approach the infraspinatus muscle by separating the scapular bone from the surrounding tissues.
We differentiated the infraspinatus muscle from the deltoid, trapezius, teres major, teres minor, and latissimus dorsi muscles by US scanning and marked the tender points on the skin by palpating the muscle. By positioning the probe on the marked points and turning the probe for the best view, we obtained the image of the target area (Figs. 1, 2). Color Doppler images were used to avoid the neurovascular bundle. Under US guidance, a 25-gauge, 2.6-cm needle connected to a 5-mL syringe containing a mixture of 4 mL of 0.5% lidocaine and 1 mL of 40 mg of triamcinolone was inserted into the infraspinatus muscle at the region where the tender spot was palpated. In the case of multiple tender spots in one muscle, the injections were repeated for all tender spots.
The sequence of the injection sites was determined at each treatment period in terms of the decreasing order of pain severity in the tender points when palpated. The injection volume per tender point was 0.5 mL. No more injections were done once all the prepared solution of 5 mL had been used up (at most, there could be 10 injections per treatment session) or when no more palpated tender point were found. With the use of an out-of-plane method, we could see the needle passing through the skin and adipose tissue to penetrate the muscle. The physiatrist observed the LTRs on the US while performing the trigger-point injections. The needling was repeated to elicit as many LTRs as possible. If no LTR was observed after 10 attempts, the needling was stopped and a mixture solution was injected. The injection site was pressed to ensure proper hemostasis after the procedure. Trigger point injections were carried out in all MTrPs of the muscle at 2-week intervals. Additional injections were not considered if patients were satisfied with the reduction in discomfort or pain severity, or if patients did not want another injection for some reason. The patients were taught to do stretching exercise (repeated 10?20 times daily) and to avoid any posture that might aggravate the symptoms.
Data collection
Demographic and clinical data including age, gender, affected side, and the duration of symptoms were collected. Pain intensity, duration of symptoms, chief complaint area, referred pain pattern, the number of injections, and the number of LTRs were recorded, and the distribution of MTrPs in the muscle was established in terms of the sites of LTRs that were given US-guided injections (Fig. 3).
Pain intensity was measured by using a 10-cm horizontal VAS, which ranged from 0 (no pain) to 10 (worst imaginable pain). VAS was assessed at baseline and at 2 weeks after each injection.
Statistical analyses
We carried out descriptive analyses of patient informa-tion and characteristics of MTrPs in the infraspinatus muscle. For patients with MTrPs in both infraspinatus muscles, pain intensity, duration of symptoms, chief complaint area, referred pain pattern, the number of injections, and the number of LTRs were evaluated on each side. Evaluation of the effect of the trigger-point injections used the Shapiro-Wilk test of the VAS data acquired at baseline and at 2 weeks after the first injection to find out whether the distribution was normal. When the Shapiro-Wilk test showed a normal distribution for these parameters, a paired t-test was used to compare parameters before and 2 weeks after the first injection. Statistical significance was set at a p-value of <0.05. SPSS ver. 21.0 software (IBM, Armonk, NY, USA) was used for all statistical analyses.
RESULTS
We reviewed the medical records of 446 patients with suspected MTrPs in the infraspinatus muscles between March 2013 and November 2015. Of these, 297 patients (221 females and 76 males) were eligible for this study.
Because there were 83 patients with MTrPs in both infraspinatus muscles, there were 380 cases of infraspinatus muscles with MTrPs that satisfied the inclusion criteria.
In 83 patients with MTrPs in both infraspinatus muscles, both muscles were evaluated separately for the duration, pain severity, chief complaint area, and pattern of referred pain. The demographic and clinical characteristics of 297 patients and the clinical characteristics of the 380 infraspinatus muscles with MTrPs are summarized in Table 1.
Among the 297 patients, there were 103 with a medical history of shoulder disease, including rotator cuff disease (n=103, 34.7%), sports or work-related injury without shoulder and cervical spine disease (n=89, 30.3%). cervical spine disease (n=61, 20.5%), and shoulder disease combined with cervical spine disease (n=44, 14.8%). Among the patients with work-related injury, we found that 17 (5.7%) took care of the children.
In the 380 infraspinatus muscles with MTrPs, the most common chief complaint area was the scapular area; the next most common was deep in the front of the shoulder (Table 1). One hundred thirty-one cases had referred pain except in the areas of chief complaint; the most common area was the anterolateral aspect of the arm (above the elbow) (Table 2).
The LTRs necessary for diagnosing MTrPs were identified in all 380 infraspinatus muscles. However, the number of LTRs was recorded in the medical charts for only 153 cases. Of these, 38 cases (24.8%) had fewer than 5 LTRs. Cases with 6–10, 11–15, 16–20, and >10 LTRs were 45 (29.4%), 46 (30.1%), 24 (15.7%), and 70 (45.8%), respectively.
Fig. 3 summarizes the distribution of MTrPs in the infraspinatus muscles based on the scapular bone in 297 patients. For all 380 cases, 1,468 MTrPs were found, averaging 4.9 MTrPs per muscle.
Among the 380 cases, the effect of the trigger-point injections was assessed for 135 cases. One injection was given to 16 (11.9%) of the 135 patients, 2 injections at an interval of 2 weeks for 88 patients (65.2%), and 3 injections every 2 weeks for 31 patients (23.0%). There was a significant decrease in the VAS at 2 weeks after the first injection compared to the baseline (p<0.001). The mean value decreased significantly from 7.11 (SD=1.45) pretreatment to 3.74 (SD=1.53) after the first treatment.
DISCUSSION
There are three important findings in this study. First, one of the main symptoms of MTrPs in the infraspinatus muscle is scapular pain. Second, active MTrPs were almost always multiple rather than single in the infraspinatus muscle on the painful side. Third, inactivation of active MTrPs in the infraspinatus muscle significantly decreased pain intensity.
The main symptom of MTrPs in the infraspinatus muscle was pain deep in the front of the shoulder, including the anterior deltoid area, in previous studies [9,15-18]. Although the pain from MTrPs was frequent deep in the front of the shoulder, pain in the scapular area was more
common in this study. These findings may depend on the differences in the definition of the MTrPs, the patient population, and the exactitude of the questions asked to patients during the medical examination.
First, MTrPs can exist within skeletal muscle tissue, aponeurosis (fascia) of the muscle, or the tendon, but this study was restricted to MTrPs within the infraspinatus muscle tissue and/or fascia of the muscle, which is the most common type of MTrPs [19].
Second, we did not exclude patients who had a history of cervical spine disease or shoulder lesion if the patients met the criteria of MTrPs in the infraspinatus muscle. Third, because patients may not be able to distinguish scapular pain from shoulder pain, the physiatrist asked questions to find out if the pain presented exactly around the scapular area during the medical examination. If the physiatrist did not ask specifically about scapular pain, a patient could have thought the question was about shoulder pain.
Referred pain is a pain felt in other than the true site of origin [20]. In this study, the locations of referred pain from MTrPs in the infraspinatus muscle were, in order of frequency, the anterolateral aspect of the arm (above the elbow), the lateral forearm, the upper posterior neck, and the radial aspect of the hand (including a finger). Our
results were similar to those of a study of 193 patients, in which the anterolateral aspect of the arm (46%) was the most frequent site of the referred pain, followed by the lateral forearm (21%), the posterior neck (14%), and the radial aspect of the hand (13%) [9,11,15,16,18,21,22].
When the referred pain is on the radial aspect of the hand, it was especially important to differentiate it from cervical radiculopathy, mainly at the C5 or C6 level [23].
The range and site of the referred pain can depend on the location and intensity of the MTrPs in the infraspinatus muscle, and further study is required. MTrPs in the infraspinatus and teres minor muscles often occur together and are often incorrectly assessed as rotator cuff lesions or cervical discogenic pain. In addition, MTrPs in the infraspinatus muscle are often incorrectly assessed as osteoarthritis of the shoulder joint, entrapment of the suprascapular nerve, or bicipital tendinitis [19]. Also, MTrPs in the infraspinatus muscle should be differentiated from those in the teres major, supraspinatus, anterior deltoid, subscapularis, and pectoralis major muscles [19].
One of the main contributions of our study is the finding that there were multiple, not just single, active MTrPs in the infraspinatus muscle on the painful side. Furthermore, there are many LTRs per infraspinatus muscle, and cases of more than 10 LTRs were frequently observed (45.8%). If LTRs are elicited during injection, especially if the fast-in–fast-out technique was used, immediate pain relief could be achieved more often [24,25]. Patients can fail to experience immediate and complete pain relief if the LTRs are not elicited during a trigger-point injection.
After injection into one responsive locus, other LTRs can be elicited. These procedures should be repeated until all (or as many as possible) responsive loci are injected [26]. To our knowledge, the number of LTRs has not been reported previously. Therefore, these results highlight the importance of searching for multiple active MTrPs regions and LTRs within one muscle in patients with myofascial pain syndrome in the infraspinatus muscle. Multiple MTrPs in the same muscle can each contribute to the overall referred pain pattern.
Trigger-point injection of the infraspinatus muscle resulted in excellent outcomes, and VAS scores decreased after treatment. We suggest that, in a patient with MTrPs in the infraspinatus muscle, trigger-point injection of the infraspinatus is effective for both diagnosis and treatment when the scapular pain is suspected to originate from the
infraspinatus muscle.
MTrPs in the infraspinatus are usually activated by an acute stress or by multiple overload stresses. These MTrPs may become active and induce pain under the influence of certain perpetuating factors, such as repetitive and sustained shoulder activities [27,28]. This could be the explanation for the 17 patients without shoulder lesion who took care of children. When the shoulder is abducted and flexed, the infraspinatus muscle shows less activity than the supraspinatus muscle [29]. However,
there is a marked increase of infraspinatus activity at over 140°of abduction. Therefore, when the patient carries heavy loads for a long time with the shoulder abducted above the acromion level, the infraspinatus muscle could be damaged. These mechanisms could explain the cases of MPS in women without underlying disease who were actively involved in child care. Since the infraspinatus muscle, unlike the supraspinatus muscle, is likely to be strongly activated in movements that are unusual and transient, acute overload could be much more likely to develop MTrPs than tasks that impose a sustained overload [11].
The muscle imbalance may also keep the MTrPs active and induce recurrent pain. Since MTrPs can induce changes in normal muscle-activation patterns and subsequent motor dysfunction, identifying and inactivating MTrPs should improve motor function, release muscle stiffness, and restore normal biomechanics of the shoulder [30].
It is important to know the common sites of MTrPs in the infraspinatus muscle in order to provide guidance on the clinical identification of MTrPs in this muscle. Careful palpation frequently discloses multiple tender spots in the infraspinatus muscle as indicated by the multiple lesions. In previous studies, the most common MTrPs region was caudal to the junction of the most medial and adjacent quarter of the length of the scapular spine (upper medial lesion) [11]. The next most common MTrPs region was caudal to the midpoint of the scapular spine (lateral upper lesion) [11]. In this study, the common MTrPs region was similar to that found by Travel, but was more broadly positioned, and the inferior angle of the scapula was more frequently observed. Because the infraspinatus muscle is quite broad and palpating all of it during the physical examination could be time-consuming, this study could provide a helpful guideline for identifying MTrPs in the infraspinatus muscle.
US-guided injection is useful for detecting LTRs in deeply located muscles and for controlling the depth during injection for even less-accessible muscles. US guidance can also reduce inadvertent injuries that could be caused by improper needle placement. It might seem unnecessary to use US-guided injection, because the infraspinatus muscle is located superficially, and the needle is less likely to injure surrounding tissues, such as the lung, inadvertently. However, by using US-guided injection, we could observe more LTRs to improve the effects of injection, differentiate the neighboring teres major, deltoid, and trapezius muscles in order to diagnose more accurately, and provide feedback for the treatment by recording with built-in video. These strengths could be worthy of attention.
There are some limitations to be considered in our study. First, because the study was retrospective, we could have missed information required for accurate analysis.
Second, we conclude the therapeutic effects of trigger point injections without comparison to a control group. Nevertheless, we could not ignore the significant decrease in the VAS scale (more than 3 points) from injections during short-term treatment.
Third, we investigated only one referred pain pattern per case. If multiple tender points exist, there could be many different referred pain patterns depending on the location, number, and pain severity of the tender points. This is also a limitation of a retrospective study, which could be complemented by further prospective studies. Fourth, the follow-up period of the therapeutic effect of the trigger-point injections was relatively short. Although there was no long-term follow-up, the long-term effects of trigger-point injections for MPS in the infraspinatus
muscle would not differ from those for other muscles. If the underlying etiologic lesion cannot be eliminated, the effect of one trigger-point injection usually lasts about 2 weeks [13]. Inactivation of active MTrPs, however, is necessary for some situations, including the presence of severe and intolerable pain, pain or discomfort that interferes with functional activities, and persistent pain and tightness. The same principle can be applied to the infraspinatus muscle.
Fifth, the selected group of patients was not homogeneous. In particular, some patients with shoulder or cervical spine lesions were included in this study. MTrPs could be secondary to pathologic conditions such as chronic repetitive minor muscle strain, poor posture, systemic diseases, and musculoskeletal lesions (such as strain, sprain, enthesopathy, bursitis, arthritis, and spinal disc lesion) [2,3]. But for the patients with a history of shoulder or cervical spine lesion in our study, their lesions were not their main reason for visiting a clinic. In addition, their symptoms satisfied MTrPs criteria and, ironically, their MTrPs were less frequent than for patients without a history of shoulder or cervical spine lesion [1].
In conclusion, our findings of MTrPs in the infraspinatus muscle and the therapeutic effect of trigger-point injections in that muscle may provide clinicians with useful information in diagnosing and treating myofascial pain syndrome of the infraspinatus muscle.
CONFLICT OF INTEREST
No potential conflict of interest relevant to this article was reported.
