Osteoporosis is often cited as a contraindication for pedicle screw fixation.是什么意思？

Osteoporosis is often cited as a contraindication for pedicle screw fixation.

骨质疏松一直被列为椎弓根螺钉固定的禁忌症.

is

vt.& vi. 是（be的三单形式；n. 存在；

例句
Bollinger 'RD' is a rare, highly prized wine.
博林格RD香槟是一种名贵的备受推崇的葡萄酒。

often

adv. 常常，经常，时常，再三；

例句
Genetic abnormalities are more often associated with faults in paternal DNA than in maternal DNA.
相对于母本DNA,基因畸变往往更多地与父本DNA上的缺陷相关。

cited

v. 引用( cite的过去式和过去分词 )，传唤，记起，[军事]传（或通）令嘉奖；

例句
The officer cited the federation's rule on affiliation.
该官员引用了联邦政府对于隶属关系的规定。

as

adv. 同样地，一样地，例如；prep. 作为，以…的身份，如

例句
As far as I can recall, Patti was a Smith.
我记得帕蒂是姓史密斯的。

contraindication

n. 禁忌征候；

例句
Osteoporosis is often cited as a contraindication for pedicle screw fixation.
骨质疏松一直被列为椎弓根螺钉固定的禁忌症.

for

prep. 为，为了，倾向于，关于，当作；conj. 因为，由于；

例句
I've come looking for a bit of advice.
我特来讨教。

screw

n. 螺丝钉，螺旋桨，螺旋状物，（螺丝的）转，扭，吝啬

例句
There should be no exposed screw heads...
螺钉顶端不应该外露。

fixation

n. <心>固着，固恋；

例句
The country's fixation on the war may delay a serious examination of domestic needs.
该国对这场战争的执迷可能会令其不能及时认真地审视国内需求。