Division of Nuclear Medicine, Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA.
Clin Ther. 2011 Dec;33(12):1894-903. doi: 10.1016/j.clinthera.2011.10.013. Epub 2011 Nov 17.
Single-photon emission computed tomography (SPECT) has been employed in the study of altered regional cerebral blood flow (CBF) in experimental and chronic pain. CBF patterns have not been evaluated in patients with acute postoperative pain.
The purpose of this pilot study was to employ SPECT to measure CBF distribution associated with postoperative dental pain and to compare these CBF patterns to subsequent images in the same patients who were experiencing pain relief versus continued or worsening pain who had received active or placebo analgesic interventions. The primary outcome measure was the percentage change in blood flow in various regions of interest.
Twenty-two healthy individuals (10 males and 12 females, age range 20-29 years) who underwent the removal of ≥1 partial or full bony impacted mandibular third molars were evaluated for pain intensity as the local anesthesia dissipated, employing a 0 to10 numeric rating scale (0 = no pain; 10 = worst imaginable). When the subjects' pain level reached ≥4/10, they were injected intravenously with 260 MBq of technetium Tc 99m bicisate (ethyl cysteinate dimer). Under double-blind conditions and 10 minutes before being placed in the SPECT scanner, the first 10 subjects were randomized to receive intravenous ketorolac 15 mg or saline while the remaining 12 subjects were randomized to receive by mouth either ibuprofen 400 mg, ibuprofen 200 mg, acetaminophen 1000 mg, or placebo. One hour after drug administration, subjects were reevaluated for pain, injected with 925 MBq of technetium Tc 99m bicisate, given rescue medication if required, and then rescanned. CBF ratios were obtained for regions of interest and by normalizing to average whole brain activity.
Subjects generally had a moderate degree (mean [SD], 7.3% [4.0%]) of thalamic asymmetry on initial scans with pain; after treatment, subjects reporting worsening pain regardless of the intervention had higher thalamic asymmetry (8.1% vs 2.8%) than those reporting relief of pain. Subjects who reported reduced pain after the intervention had significantly different (P < 0.05) mean CBF changes compared with those reporting worsening pain in the left prefrontal cortex, left sensorimotor area, right anterior cingulate, and right caudate.
Acute postoperative dental pain was associated with moderate thalamic asymmetry that improved following successful pain management. Sustained or worsening pain was associated with increased CBF in brain regions associated with pain pathways, whereas pain relief was associated with decreased activity in the same areas.
单光子发射计算机断层扫描（SPECT）已被用于研究实验性和慢性疼痛中的局部脑血流（CBF）改变。尚未在急性术后疼痛患者中评估 CBF 模式。
本初步研究旨在使用 SPECT 测量与术后牙科疼痛相关的 CBF 分布，并将这些 CBF 模式与同一患者的后续图像进行比较，这些患者在接受积极或安慰剂镇痛干预后经历疼痛缓解或持续或加重疼痛。主要观察指标为各感兴趣区域的血流百分比变化。
22 名健康个体（10 名男性和 12 名女性，年龄 20-29 岁）接受了≥1 颗部分或完全骨内埋伏下颌第三磨牙的切除，在局部麻醉消退时评估疼痛强度，采用 0 到 10 数字评分量表（0 = 无痛；10 = 可想象的最严重疼痛）。当患者的疼痛水平达到≥4/10 时，静脉注射 260MBq 锝 Tc 99m 双半胱氨酸（乙基半胱氨酸二聚体）。在双盲条件下，在放入 SPECT 扫描仪前 10 分钟，前 10 名受试者随机静脉注射酮咯酸 15mg 或生理盐水，而其余 12 名受试者随机口服布洛芬 400mg、布洛芬 200mg、对乙酰氨基酚 1000mg 或安慰剂。给药后 1 小时，对患者进行疼痛评估，如果需要，给予解救药物，然后重新扫描。获得感兴趣区域的 CBF 比值，并通过平均全脑活动进行归一化。
受试者在有疼痛的初始扫描时通常表现出中等程度的丘脑不对称（平均[标准差]，7.3%[4.0%]）；治疗后，无论干预措施如何，报告疼痛恶化的受试者的丘脑不对称程度更高（8.1%比 2.8%），而报告疼痛缓解的受试者则较低。与报告疼痛加重的受试者相比，报告疼痛减轻的受试者的左前额叶皮质、左感觉运动区、右前扣带回和右尾状核的 CBF 变化有显著差异（P<0.05）。
急性术后牙科疼痛与中度丘脑不对称相关，在成功管理疼痛后改善。持续或加重的疼痛与与疼痛通路相关的脑区 CBF 增加有关，而疼痛缓解与同一区域的活动减少有关。
