肌肉注射對於顳顎關節炎緩解後咬肌疼痛的治療

Abstract

目的︰ 在口顏部疼痛的病人中，咬肌(masseter)疼痛十分常見，但是往往難以有效地治療。許多治療方式可用以減輕其症狀，但並不一定有哪一種是特別有效，因為咬肌疼痛有可能來自不同病理生理原因。臨床上常見顳顎關節炎的病人，在服用非類固醇消炎藥物(NSAIDs)之後,顳顎關節炎疼痛症狀減緩，但是咬肌疼痛情形卻沒有改善，甚至更趨明顯，並可在咬肌的肌肉中摸到緊繃肌帶(taut band)，我們假設這種局部性的肌肉疼痛，是顳顎關節炎引發周邊肌肉神經敏感化所導致。臨床上此類病人局部肌肉疼痛以激痛點肌肉注射(trigger point injection)治療往往有不錯的效果, 此項研究的目的，便是限制在如此的適應症時，激痛點肌肉注射是否能有效地治療減輕病人的症狀。 材料和方法︰ 本實驗受測者共有50位18至45歲之女性，分為實驗組25位 (平均年齡為29.52±6.16歲)及對照組25位(平均年齡27.28±6.95歲)，受測者納入條件為：經臨床檢查起初有顳顎關節炎症狀，經服用NSAIDs治療一個禮拜後，顳顎關節炎症狀緩解，咬肌有疼痛結節（taut band）者。經病患同意，其中25位符合條件之病患安排復健科主治醫師進行咬肌之激痛點肌肉注射1% Xylocaine&reg; (Lidocain) (Hong C-Z, 1994)，為實驗組，另25位進行放鬆練習、居家按摩和熱敷，為對照組。牙科醫師以壓痛測試計(Algometer)於患者咬肌的緊繃肌帶上進行肌肉疼痛閾值(PPT)的量測，並記錄之，同時記錄患者主觀疼痛強度值(VAS)及最大開口度(MMO)。牙科醫師於注射後20分鐘，ㄧ個禮拜，兩個禮拜，ㄧ個月，追蹤測量記錄這些數值的改變，以評估激痛點注射後之效果。 結果: 比較實驗組和對照組，實驗組於一個月後之PPT值大於實驗前，大於對照組，恢復到和正常人差不多，且具統計顯著性(p<0.05)。VAS值小於實驗前，小於對照組，且具統計顯著性(p<0.05)。MMO值大於實驗前，大於對照組，恢复到和正常人差不多，且具統計顯著性(p<0.05)。對照組在一個月後之PPT值VAS值和MMO值與實驗開始前相比沒有明顯改變。實驗組和對照組相比，進行激痛點肌肉注射一個月後，疼痛程度降低，張口程度增加。 結論: 在短期治療顳顎關節炎緩解後之局部咬肌疼痛，肌肉激痛點注射產生疼痛緩解和恢復接近全距運動範圍的療效。

Objectives: Among orofacial pain patients, masseter myalgia is a common but also a frustrated problem. Many treatments have been proposed to alleviate the symptom, however, no single treatment can yield a constant positive outcome. Patients presenting masseter myalgia might have different underlying patho-physiologies; such mechanism heterogeneity might account for the embarrassment of treatments. It is commonly seen clinically that the local masseter maylagia appeared following initial reduction of TMJ arthralgia after taking NSAIDs. Interestingly hardly further improvement can be seen by taking more NSAIDs; and painful taut bands can be easily revealed within masseter muscle. We hypothesized that such local myalgia might be a consequence of sensitization due to inflammation within or around TMJ. Some patients have received trigger point injection in the masseter muscle and showed very positive responses. The aim of this study was thus to evaluate the effects of muscle injections in treating local masseter myalgia confined to a restricted indication. Materials & Methods: Patients who met the following inclusion criteria were suggested to have muscle injection therapy. The chief complaint of first visit was the pre-auricular pain, which could be provocated either by maximal mouth opening or palpation on TMJ. This pain should respond well with NSAID of anti-rheumatic usage, mostly Votaren 100 mg/day for a week. When further medication won’t result in more pain reduction, and at least in the ipsilateral masseter muscle should present painful taught bands. These patients were then sent to an experienced physician in the clinic of physical therapy for muscle injection. 1% xylocaine without epinephrine was used for muscle injection through standard trigger point injection technique (Hong C-Z, 1994). If patient met the inclusion criteria but didn’t want to accept muscle injection, self-care protocols including relaxation exercises, hot packing, and muscle massage were instructed and served as controls. Pressure-pain threshold (PPT) and visual analog scale (VAS) mouth opening (mmo) were measured at baseline, 1 week, 2 weeks, and 1 month. An additional measurement was done 20 minutes after injection. Results: 25 female patients (mean age 29.45±6.16 years) received muscle injection treatment and 25 female patients (mean age 27.3 ±6.95years) were as controls. Treatment outcomes of muscle injection and self-care program represented by PPT and VAS are shown from Fig. 1 to Fig. 4. After the injection, the severity of local myalgia was worsen initially, but in one month it reduced significantly in comparison with the baseline (Paired t-test, p<0.05 for both PPT and VAS). In the control group, there was no significant difference between PPT measured at baseline and one month (Paired t-test, p>0.05). The VAS scoring was no significant difference between one month follow up and baseline (Paired t-test, p>0.05). All subjects received injection showed increased mmo at one month, however, only 8 controls had mmo increasing at one month. Conclusions: Muscle injection seems to be effective, at least short-term, in treating local masseter muscle pain after TMJ inflammation has been controlled.