全身關節不穩定性與顳顎關節結構紊亂關係之探討

Abstract

實驗目的： 顳顎關節內部紊亂與關節盤異位有關，由核磁共振影像顯示異位的關節盤其位置與型態會隨著時間而改變，造成不同程度的運動障礙，範圍從單純的關節聲響到張口受限。然而顳顎關節的內部結構紊亂與臨床功能障礙之間的關聯性很低，而內部的結構紊亂應該被當成是診斷的標準，所以在本實驗中顳顎關節結構紊亂的鑑定及分類，都是經由核磁共振影像的判讀來確定。 對於顳顎關節結構紊亂及與其合併產生的退行性關節疾病，其盛行率女性高於男性，而且好患年齡層可降低到青春期。對於這類異位的關節盤，關節盤韌帶應該先損害，接著才是關節盤的移位，所以我們假設全身性或局部性的關節鬆弛，可能是造成顳顎關節結構紊亂的致病因子，由文獻中得知經由測量全身性關節運動範圍並無法得到與顳顎關節結構紊亂關係一致的結果，其中原因可能包括他們都是以臨床功能障礙來當成判斷顳顎關節結構紊亂的診斷標準，量測全身性關節運動範圍方法不一致或是缺少對照組。此外經由顳顎關節動態核磁共振影像，可見在一個連續的張口運動中，不可復位的關節盤會持續壓迫及摩擦下顎髁骨，我們假設在關節盤與下顎髁骨間的這種不利接觸的機械作用將會引發骨骼變性，如果髁骨的本身機械強度低，則可能傾向於髁骨破壞。 因為顳顎關節結構紊亂及與其合併產生的退行性關節疾病呈現獨特的人口統計學分佈，我們假設有顳顎關節結構紊亂的年輕女性，可能起因於肌肉骨骼系統的不穩定性，所以在本篇論文中，我們評估幾種可代表肌肉骨骼系統不穩定性的參數，包括全身性關節的運動範圍、骨密度及體質指數等，探究其與顳顎關節結構紊亂之間的相關性。 實驗方法： 這是一個橫段面性的實驗，實驗組包括66位病患(均為女性)，他們的顳顎關節在核磁共振影像中顯示為結構紊亂，控制組包括30位年齡相符的無症狀女性(平均年齡為23.2 ± 2.6 歲)，他們的顳顎關節於核磁共振影像中顯示為正常，歸為正常組。根據核磁共振影像再將實驗組分為兩組，一組為不可回復的關節盤異位組 (50 人，平均年齡為22.6 ± 2.7 歲)，包括至少一個顳顎關節為不可回復的關節盤異位；另一組為可回復的關節盤異位組 (16人，平均年齡為22.3 ± 2.7 歲)，包括至少一個顳顎關節為可回復的關節盤異位，而無任一顳顎關節為不可回復的關節盤異位。對於評估全身性關節鬆弛度，我們量測第五手指的伸展(被動性)、手腕向內彎曲後手拇指與前臂的貼和程度(被動性)、手肘伸展(主動性)、膝關節伸展(主動性) 、軀幹前下彎(主動性)及踝關節屈曲(主動性)。同時也量測代表全身的骨密度(包括腰椎、全髖及股頸部)及體質指數(體重/身高2) (公斤/公尺2)。統計方法使用單因子變異數分析、皮爾森線性相關分析、卡方統計及邏輯式回歸分析。 實驗結果: 左側膝關節伸展及軀幹前下彎，在正常組 (分別為 -0.9 度及23.5 公分) 顯著小於不可回復的關節盤異位組 (分別為2.3 度及29.1 公分) (p< 0.05, ANOVA)，其餘的關節伸展或屈曲程度，在正常組與顳顎關節結構紊亂組彼此之間，並無顯著差異 (p> 0.05, ANOVA)。腰椎及全髖骨密度在正常組 (1.002 g/cm2) 顯著大於不可回復的關節盤異位組 (0.924 g/cm2) (p< 0.05, ANOVA)。體質指數在正常組 (20.7 kg/m2) 顯著大於可回復的關節盤異位組 (19.4 kg/m2)及不可回復的關節盤異位組 (18.9 kg/m2) (p< 0.05, ANOVA)。左右兩側全身性關節運動範圍的相關性很高 (相關係數從手肘伸展的0.723到踝關節屈曲的0.889)，例外者為具弱相關的膝關節伸展 (相關係數為0.520)。左右兩側第五手指伸展與手拇指-前臂貼和程度之間具有弱負相關性 (相關係數從 -0.269 到 –0.414)。 左右兩側手拇指-前臂貼和程度與踝關節屈曲間有弱正相關 (相關係數從0.320 到0.372)。利用邏輯式回歸模型，以體質指數及腰椎骨密度當作自變數，其正確預測正常組的百分比為56.7%，而正確預測顳顎關節結構紊亂組的百分比為92.4%。 結論： 與顳顎關節正常者相比較，患有顳顎關節不可回復關節盤異位者，將會有較高的機會，擁有前下彎時較僵硬的軀幹，較低的體質指數及較低的腰椎骨密度。

Objectives: Temporomandibular joint (TMJ) internal derangement (ID) is believed to be associated with the displaced or misaligned disc. MRI Image evidences have indicated that the position as well as the morphology of the displaced discs could change over time and resulted in varied degrees of movement interferences, ranging from simple joint noise to permanent mouth opening limitation. However, the relationship between the structural derangement and functional derangement of the TMJ was low and the structural TMJ derangement should be used as the diagnostic gold standard. Therefore, in this study the TMJ ID was defined as the structural TMJ derangement according to MRI findings. Females have higher prevalence of TMJ ID and the ID associated degenerative joint disease (DJD) than males have. These differences were noticeable as early as in the age of adolescents. For the misaligned discs, impairment of the disc attachments was supposed to be occurred even prior to the disc displacement. Therefore, ligament laxity, systemically or locally, was hypothesized as a risk factor predisposing to systemic joint instability and the TMJ ID. Most clinical trials by measuring the range of motion (ROM) of single or multiple joints had no consistent results to support this hypothesis. Since the functional derangement is not able to represent the structural derangement, the measuring method of ROM was not consistent or the control group was usually missing. True dynamic TMJ MRI has revealed that the condyle pressed/rubbed with the non-reduced disc continuously during mouth opening. The unfavorable contact mechanics between the condyle and the misaligned disc was hypothesized to initiate the degeneration. If the mechanical strength of the bony counterparts was low, they might prone to be destructed. Because the ID and DJD of the TMJ showed a unique demographic distribution, we hypothesized that young female patients having the structural TMJ derangement might be attributed to instability of the musculoskeletal system. To test this hypothesis, we tried to evaluate the relationship between certain corporal parameters, which might represent the instability of the musculoskeletal system, including range of motion (ROM) of body joints, bone mineral density (BMD), and body mass index (BMI) etc., and structural TMJ derangement, which was diagnosed and graded according to their manifestations revealed by MRI. Materials and methods In this cross-sectional study, 66 female subjects, whose TMJs were proved with MRI to have structural derangement, have been selected as experimental group to participate in this study. Thirty age-matched female asymptomatic subjects (mean age 23.1 ± 2.6 Y/O) whose TMJs were also normal revealed by MRI, were included as the control and named as Normal group. According to the MRI, the experimental group were further divided into 2 subgroups, namely disc displacement without reduction (DDw/oR) (50 subjects, mean age 22.6 ± 2.7 Y/O) and disc displacement with reduction (DDwR) (16 subjects, mean age 22.3 ± 2.7 Y/O). ROM of the fifth finger extension, thumb apposition, elbow extension, knee extension, trunk flexion, and ankle dorsal flexion, were measured to assess the body joint hypermobility. BMD of lumbar spines, total hip, and femoral neck and BMI (weight / height2) (kg/m2) were also measured. ANOVA, Pearson’s linear correlation, chi-square test, and binary logistic regression analysis were used for statistic analyses. Results: ROM of the individual measured joints, except the left knee extension and trunk flexion, is not significant difference among Normal, DDwR, and DDw/oR groups (p> 0.05, ANOVA). The degrees of left knee extension and trunk flexion of Normal group (-0.9 degree and 23.5 cm, respectively) were significantly lower than that of DDw/oR group (2.3 degree and 29.1 cm) (p<0.05, ANOVA). BMD of lumbar and total hip were significantly higher in Normal group (1.002 g/cm2) than that of DDw/oR group (0.924 g/cm2) (p< 0.05, ANOVA). BMI of Normal group (20.7 kg/m2) were significantly higher than those of DDwR (19.4 kg/m2) and DDw/oR (and 18.9 kg/m2) (p< 0.05, ANOVA). There were strong positive correlations between right and left joint flexibility (from r= 0.723 for elbow extension to r= 0.889 for ankle dorsal flexion) except knee extension (r= 0.520). There were weak negative correlations between the fifth finger extension and thumb apposition of both hands (r= -0.269 to –0.414). There were weak positive correlation between both side thumb apposition and ankle dorsal flexions (r= 0.320 to 0.372). There was a moderate to high percentage of correct in prediction of Normal (56.7%) and ID (92.4 %) with logistic regression model on variables of BMI and lumbar BMD. Conclusion: Compared with subjects with normal TMJ, patients with DDw/oR will have a higher chance to possess stiff trunk to flexion, lower BMI and lower lumbar BMD.