Can chronic neuropathic pain
following thoracic surgery be
predicted
during the postoperative period?
Robert D. CardioVascular and Thoracic Surgery 9(2009)999-1002
Introduction
1.Chronic pain following thoracic surgery is
common(>50%)
2. This pain has a significant impact on
patient `s live(>40% report that pain is their
Worst thing and it limited their daily live)
The reason of the chronic pain
following thoracic surgery
The course is not fully understood
But, intercostal nerve damage and subsequent dysfunction has long been implicated
intercostal nerve damage
Pressure related to
rib retraction
Traction on the nerve
The studies about the chronic
neuropathic pain(CNP)
Steegers et al. used a questionnaire
to determine the incidence of CNP following
Thoracic surgery, concluding 53% had
neuropathic pain
However,these studies were retrospective
postal surveys and with no information on the
existence of neuropathic pain before
the operation
The aim of the study
1. The incidence of ANP and CNP
2. hypothesized that the occurrence of ANP
Would be associated with CNP characteristics
at three months follow-up
Methods
Prospective ,observational cohort study
Video assisted thoracic surgery
Include
Posterolateral thoracotomy
Undergone VATS or thoracotomy
Exclude
Previously diagnosed neuropathic pain
Pregnant
Validated neuropathic pain
screening tools
1.Leeds Assessment of Neuropathic Symptoms
and Signs (LANSS)
2. self-complete version(S-LANSS)
LANSS Pain scale
S-LANSS Pain scale
Include patients
The day before
scheduled surgery
withdrawn
LANSS score
postoperative
Positive LANSS scores
24h after regional or local
anaesthetic infusion or
injection had ceased
Repeated the LANSS score
Three months
following operation
S-LANSS questionnaire
LANSS or S-LANSS
score >12
neuropathic
Those failing to return the post were
telephoned after a further two weeks
and by telephone interview
Statistic
1. Relative risks between ANP and CNP with
Fisher`s exact test
2. Any possible relationships between CNP
and other factors using stepwise logistic
regression analysis with the statistical
package STATA
Result
The postoperative LANSS score
was performed anaverage of
3 days following Surgery
19 (22%)
had CNP
87 of these 100 patients completed
S-LANSS ,of these 87 patients, 19
(22%) had CNP
85 of the 100 patients completed
53 (62%) had
the NRS, 53 (62%) had chronic
chronic pain
pain,and of those patients18 (21%)
had a pain score of between 5 and
10 on the NRS scale
18 (21%) had a
pain score of
between 5-10
87 of these 100
patients completed
S-LANSS
complete
lost
85 of the 100
patients completed
the NRS
complete
lost
Result
Had a surgically placed catheter and
continuous infusion of plain bupivicain
eduring the postoperative period
Result
Result
Item1,Does your pain
feel like strange,
unpleasant sensation
in your skin? Words
like prickling, tingling, Patients with ANP were
pinsand needles was more likely to have CNP
more predictive of 3 at 3 months than those
without ANP
months CNP
[5/8(62.5%)vs17/79(1
A relative risk of
8%) relative risk
4.5(95%CI 2.33.5(95%CI 1.7-7.2)]
8.7)
Patients with CNP had higher average LANSS
scores during the postoperative period
(median=7) than those who didn`t develop
chronic pain (median=3, P=0.007 MannWhitney U-test)
There was no correlation between CNP and
gender,type of operation or whether the
underlying disease diagnosis was malignant or
benign
Result
Old patients were more likely to have CNP
(P=0.04)
No single analgesic technique was associated
with the subsequent development of CNP.
Result
There was a correlation between the total
postoperative LANSS score and the later three
months S-LANSS total r-value of 0.33
(P>0.001)
Patients with CNP (S-LANSS≧12) had higher
NRS (medians5) than those with nociceptive
pain (median=2, P=0.002 Mann-WhitneyUtest) at 3 months follow-up
Discussion
We found that 8% of patients under going
thoracic surgery developed ANP in the
immediate postoperative period and that 22%
of patients have CNP 3 months after their
operation
Discussion
Our results show a small but significant proportion
of thoracic surgery patients have ANP characteristics
and importantly that this predicts the development
of CNP.
However,3 patients with ANP didn`t develop CNP,
suggesting that the natural history of ANP symptoms
and signs may be that over a third of cases
spontaneously resolve in the first three months
Discussion
The majority who developed CNP (74%) didn`t
have NP in the immediate postoperative period,
although they had significantly higher average
LANSS scores.
It is not clear whether this reflects a different
pathophysiological process, or if it reflects a
reduction in the sensitivity of the LANSS score
when used in the early postoperative period.
Discussion
It has not been specifically designed for use in
the early postoperative period.
More work is needed to develop a validated
tool to aid diagnosis of neuropathic pain in
the immediate postoperative period
Discussion
Our study demonstrates that the presence of
acute pain of predominantly neuropathic
origin is significantly associated with
development of CNP characteristics three
months later
术后神经病理性疼痛
国际疼痛研究会（IASP）将这种由于外周或中
枢神经系统直接损伤功能紊乱引起的疼痛称为
神经病理性疼痛。
外周神经损伤引起的神经病理性疼痛，表现为
痛觉过敏，异常痛敏，感觉缺失和自发性疼痛。
其中中枢和外周敏化在神经病理性疼痛测产生
和维持中发挥重要的作用（Millar MJ-1999）。
神经病理性疼痛发生机制
1.外周机制
1.1
1.2
1.3
1.4
1.5
多数的学者支持疼痛产生于受损伤的轴突和邻
研究发现受损伤的神经纤维钠通
近的背根神经节传播来的异位冲动；有研究表
P2X受体为配体门控离子通道，属于P2受体家族。
道的重新分布对神经病理性疼痛
明异常传入放电是感觉异常、感觉迟钝、和慢
P2X受体的配体是ATP，胞外ATP结合时P2X受体
的产生发挥重要的作用。因此钠
性神经病理性疼痛的重要原因
通道打开，允许阳离子(Na+、Ca2+等)通过。多
外周神经损伤后，重新形成的轴突末梢
通道是未来神经病理性疼痛治疗
种伤害性刺激均可引起细胞内释放ATP，ATP激
可以在被切断神经的皮肤区域重新出芽，
药物开发的重要靶点
活P2X受体引起疼痛。
但这种出芽作用在术后神经病理性疼痛
的发生中到底起何种作用，尚不完全明
确。
自发放电
离子通道表达的改变
P2X的作用
初级传入末梢的间接出芽
前炎症介质对伤害性感受器的敏化
神经病理性疼痛发生机制
2.中枢机制
Aβ 纤维传入末梢出芽
NMDA受体作用
2.1 神经病理性疼
痛的脊髓机制
抑制性中间神经元作用
细胞因子的作用
中枢敏化
胶质细胞的作用
2.2 神经病理性疼
痛的脊髓上机制
疼痛下行抑制系统的削弱和下行易化系统
的增强在中枢敏化的发生中起到一定的作
用；延髓腹内侧区（RAM）是下行易化系
统的上位中枢，外周神经损伤后其对脊髓
背角神经元的作用增强。
神经病理性疼痛诊断
1.病史和体格检查
神经病理性疼痛量表 （ Neuropathic
pain scale,NPS） 包括10项疼痛描述
符号（剧烈、尖锐、灼热、钝样、寒冷、
敏感、不舒服、瘙痒、深部和体表），
是精确有效的评估工具 。
2. NPS的疼痛性质
定量感觉测量（Quantitative
3.感觉异常、疼痛过敏、总和和感觉后效应
sensory testing，QST）：通过
对冷和冷/痛以及热和热/痛的域值
检测评估C纤维的功能
4. QST评估C纤维功能
神经病理性疼痛药物治疗进展
摘自2008第12届世界疼痛大会
三环类抗抑郁药能够减轻多发性神经病变患
者的疼痛；且曲马多与多虑平联合用药具有
协同效应；但其治疗作用需要一段时间体现。
1.抗抑郁药物
2.抗癫痫药物
3.局麻药
新的抗癫痫药物加巴喷丁同其他抗癫痫和抗
抑郁药物比较，副作用较小，效果确切。
局部利多卡因贴剂（Lidoderm）是FDA批准用
于治疗神经痛的新药，无全身性副作用，具有
广阔的应用前景 。
4.阿片类药物
5.非甾体类抗炎药物
阿片类药物治疗急性疼痛效果明确，治疗神经
病理性疼痛目前仍有争议，长期给予阿片类药
物引起副作用也是限制其应用的原因之一。
Moini等认为CCI模型大鼠痛觉过敏和痛觉异常，是
由于脊髓释放前列腺素和细胞因子所致。免疫细胞
在慢性疼痛的产生和维持中起到了很大作用 。
Thanks!!!