梨状肌出口综合征的病因学研究

Pathogenesis of piriformis syndrome： a magnetic resonance imaging-based comparison study

目的通过磁共振成像（MRI）评估梨状肌出口综合征（Ps）患者梨状肌的形态差异探讨Ps的病因学。方法纳人2015年9月至2016年10月南方医科大学南方医院30例可疑Ps患者和30例正常对照。采集Ps患者可疑病因，根据压痛点解剖位点将患者区分成亚组，通过MRI测量各亚组患者和对照组的梨状肌形态学参数：厚度（cm）、面积（cm^2）、体积（cm^3）。运用独立样本￡检验分析评估各亚组与对照组、各亚组间梨状肌形态的差异，进而分析梨状肌是否参与坐骨神经损伤，探讨坐骨神经损伤机制。结果26例患者诊断为PS。16例（61．5％）患者存在不良坐姿习惯，臀部／髋关节创伤率为0。15例（57．7％）患者压痛点位于梨状肌上缘区域（sPF组），11例（42．3％）位于梨状肌区域（PM组）。PM组患者患侧梨状肌厚度、面积、体积与对照组相比差异均有统计学意义[分别为（2．24±0．46）比（1．66±0．30）cm、（14．4±2．2）比（8．8±2．1）cm^2、（23．9±3．8）比（15．2±2．6）cm^2，t=4．699、7．437、8．291，均p〈0．05]，与sPF组相比[分别为（1．62±0．20）cm、（8．7±1．6）cm、（14．1±4．8）cm^3]差异亦均有统计学意义（t=4，640、7．631、5．589，均P〈0．05）。sPF组患者患侧梨状肌厚度、面积、体积与正常对照组比较差异均无统计学意义（t=-0．439、-0．102、-1．083，均P〉0．05）。结论臀部压痛点能够提示PS患者损伤位点。压痛点位于梨状肌上孔患者除外梨状肌压迫因素，坐骨神经及其分支的损伤可能源于不良坐姿诱因下梨状肌上孔区域软组织间接挤压。

Objective To assess the morphological parameters of the piriformis muscle through magnetic resonance imaging（MRI） so as to further elucidate the pathogenesis of piriformis syndrome （PS）. Methods From September 2015 to October 2016, 30 suspected PS patients and 30 normal controls were enrolled in this study from the Nanfang Hospital, Southern Medical University. The possible causative factors of the PS in the patients were obtained, and the PS patients were divided into subgroups according to the anatomic site of the tender regions. The parameters of the maximum thickness （ cm）, area （ cm2 ） and the volume （ cm3 ） of the piriformis muscle of both groups were measured by MRI and were statistically compared between the groups with the independent-sample t test so as to investigate the pathogenesis of injured sciatic nerve. Results Twenty-six patients were verified with PS, unhealthy sitting postures presented in 16 patients （61.5%） and no trauma history was recorded in these patients. Fifteen cases （57. 7% ） with tenderness located at the suprapiriformis foramen region （ SPF group, n = 15）, 11 patients （42. 3% ） with tenderness at the piriformis muscle （ PM group, n = 11 ）. The thickness, area and volume of the pathological side piriformis muscle in the PM group were all significantly higher than the corresponding indexes in the control group[（2.24±0.46） vs （1.66＋0.30） cm, （14.4±2.2） vs （8.8±2.1） cm2, （23.9±3.8） vs （ 15.2 ± 2. 6） cm3, respectively, t = 4. 699, 7. 437, 8. 291, all P 〈 0. 05 ] and were all higher remarkably than those in the SPF group[ （ 1.62 ± 0. 20） cm, （8.7 ± 1.6） cm2, （ 14. 1 ± 4. 8 ） em3, respectively, t = 4. 640, 7. 631, 5. 589, all P 〈 0. 05 I. No significant difference was observed in the up-mentioned indexes between the SPF and the control group （ t = - 0. 439, - 0. 102, - 1. 083, all P 〉 0. 05 ）. Conclusions Tender region at the buttock indicates the lesion site in the PS patients. The PS patients with tenderness at the suprapiriformis region might originate from another pathogenesis independent of piriformis muscle compression, the injury of the sciatic nerve or its branch maybe due to the indirect crush by the soft tissue of the suprapiriformis region under an unhealthy sitting posture.