A&R：AS患者的背痛是一种包含有神经性疼痛在内的混合性疼痛

AS患者足背机械阈值和寒冷敏感性较健康对照组相比下降

AS患者的初级体觉皮质区、岛叶皮层、前扣带皮层、前中扣带皮层及辅助运动区的脑皮质变薄，而脑灰质的体积在丘脑及豆状核壳中增加

AS患者的疼痛检测积分与初级体觉皮质区脑灰质的减少相关，与运动皮质区、前扣带皮层、前额皮质、丘脑及纹状体中脑灰质的增加相关

强直性脊柱炎（AS）的病变主要累及中轴脊柱，是引起下腰背痛症状的常见疾病。为明确AS患者的背痛是否含有神经性疼痛并描绘与AS病情相关的脑灰质异常，来自多伦多西部医院西部研究所的Qi Wu博士等人进行了一项研究。研究结果发表于2013年6月的《关节炎与风湿病》（ARTHRITIS & RHEUMATISM）杂志上。研究发现，AS患者的背痛是一种包含有神经性疼痛在内的混合性疼痛。

该研究纳入了17例AS患者，其背痛症状均由AS病情引起，且均未使用过生物制剂。同时研究还纳入了17例在年龄和性别方面与患者组相匹配的健康受试者。对所有研究对象使用疼痛检测仪（积分≤12表明其存在神经性疼痛的可能性较小）和McGill疼痛调查问卷进行测试。所有研究对象的机械阈值和温度阈值均被测定，其脑灰质通过3T磁共振成像进行评估。

17例AS患者中有11例患者的疼痛检测积分＞12分。患者组的足背机械阈值和寒冷敏感性均下降，但其疼痛阈值未发生改变。与对照组相比，AS患者的初级体觉皮质区、岛叶皮层、前扣带皮层、前中扣带皮层及辅助运动区的脑皮质变薄，而脑灰质的体积在丘脑及豆状核壳中增加。AS患者的疼痛检测积分与初级体觉皮质区脑灰质的减少相关，与运动皮质区、前扣带皮层、前额皮质、丘脑及纹状体中脑灰质的增加相关。

以上的研究结果支持AS患者合并有神经性疼痛。此外，脑灰质及与神经性疼痛相关的神经中枢异常，也与AS患者临床中出现的感觉障碍、情绪障碍、神经性疼痛综合征等临床现象相一致。这些研究结果提示，AS患者的背痛是一种包含有神经性疼痛在内的混合性疼痛。

Neuropathic pain in ankylosing spondylitis: a psychophysics and brain imaging study.
OBJECTIVE
To determine whether there is a neuropathic component in ankylosing spondylitis (AS) back pain and to delineate gray matter brain abnormalities associated with AS.
METHODS
Seventeen patients with back pain secondary to AS who were not receiving biologic agents and 17 age- and sex-matched healthy controls consented to participate in the study and were assessed using the painDETECT instrument (scores of ≤12 indicating low probability of neuropathic pain) and the McGill Pain Questionnaire. Mechanical and thermal thresholds were determined in all subjects, and brain gray matter was assessed by 3T magnetic resonance imaging.
RESULTS
Eleven of the 17 AS patients had painDETECT scores of >12. The patients had decreased mechanical and cold sensitivity on the dorsum of their feet but did not have altered pain thresholds. Compared to controls, the AS patients exhibited cortical thinning in the primary somatosensory, insular, anterior cingulate, and anterior mid-cingulate cortices and the supplemental motor area, and increased gray matter volume in the thalamus and putamen. Scores on the painDETECT in AS patients were correlated with decreased gray matter in the primary somatosensory cortex and with increased gray matter in the motor cortex, anterior cingulate cortex, prefrontal cortex, thalamus, and striatum.
CONCLUSION
The present findings indicate that neuropathic pain occurs in AS. Furthermore, abnormal brain gray matter and neural correlates of neuropathic pain are concordant with the clinical picture of AS, which includes sensorimotor and mood deficits as well as neuropathic pain symptoms. These results suggest that back pain in AS is a mixed pain condition that includes a neuropathic pain component.