脊椎手術後の早期感染症予測における未熟顆粒球数の応用価値

[Application value of immature granulocyte count in predicting early infection after spinal operation].

• Rui-Li Wu
• Xiao-Bin Li
• Bin Wang
• Li Lian

抄録

目的:

脊髄損傷患者の術後感染症における未熟顆粒球（IG）の早期予測値を評価すること。

OBJECTIVE: To evaluate the early predictive value of immature granulocytes(IGs) in postoperative infection in patients with spinal injury.

方法:

2016年10月から2018年10月までに手術を受けた脊髄損傷患者78例の臨床データを収集した。年齢は男性57人、女性21人で、平均年齢は45～63歳、（55.2±6.1歳）であった。受傷原因として最も多かったのは、脊髄外傷または変性症であった。米国脊髄損傷協会（ASIA）の脊髄損傷の分類によると、完全損傷（グレードAとB）が37例、不完全損傷（グレードCとD）が41例であった。78例はいずれも深部感覚障害と浅部感覚障害の程度が異なり、入院後にCT、MRI検査を受けた。術後1週間以内に二次感染が発生したかどうかにより、感染群と非感染群に分けた。入院時および術後1、3、6日目の未熟顆粒球絶対値（IG#）、未熟顆粒球率（IG％）、C反応性蛋白（CRP）、プロカルシトニン（PCT）、インターロイキン-1β（IL-1β）、インターロイキン-6（IL-6）、腫瘍壊死因子-α（TNF-α）を検出し、術後1週間以内に二次感染が発生したかどうかをROC曲線を用いて予測し、術後1週間以内に二次感染が発生したかどうかを比較した。ROC曲線を用いて、術後感染症の早期発見におけるIG%, IG#, PCTの予測値を比較した。IG％、IG#、PCT間の相関をスピアマン相関検定を用いて分析した。

METHODS: The clinical data of 78 patients with spinal cord injury underwent surgery from October 2016 to October 2018 were collected. There were 57 males and 21 females, aged from 45 to 63 years old with an average of (55.2±6.1) years. The most common cause of injury was spinal trauma or degeneration. According to the American Spinal Cord Injury Association (ASIA) classification of spinal cord injury, 37 cases were complete injury(grade A and B) and 41 cases were incomplete injury (grade C and D). All the 78 patients showed different degrees of deep and shallow sensory disturbances, and underwent CT and MRI examinations after admission. According to whether the secondary infection occurred within 1 week after surgery, the patients were divided into infected group and non-infected group. At the time of admission and 1, 3, 6 days after surgery, the immature granulocyte absolute value(IG#), immature granulocyte percentage(IG%), C-reactive protein(CRP), procalcitonin(PCT), interleukin-1β(IL-1β), interleukin-6(IL-6), and tumor necrosis factor-α (TNF-α) were detected. Using ROC curve to compare the predictive value of IG%, IG#, and PCT in early detection of postoperative infection. The correlation between IG%, IG# and PCT was analyzed using the Spearman correlation test.

結果:

術後1週間で33例が感染、45例が無感染（感染群、非感染群）であった。すべての患者は退院時に重篤な合併症や死亡例がないことを確認した。完全損傷の割合は感染群が非感染群に比べて有意に高く(3.979、0.046)、頸椎、胸椎の損傷が感染群で多く、非感染群は腰椎の損傷が多かった(6.226、0.044)。術後1日後のPCT、IG%、IG#の値は、感染群では0.71±0.10 ng/ml、1.08±0.10、0.20±0.05であったが、非感染群では0.51±0.05ng/ml、1.08±0.10ng/ml、0.20±0.05ng/ml、0.20±0.05ng/mlであった。51±0.08）ng/ml、0.82±0.13、0.13±0.04であり、両群間に有意差が認められた（<0.001）。術後3日目のCRP、PCT、IL-6、IL-1β、TNF-α、IG%、IG#の値はそれぞれ80.47±15.74mg/L、(2.39xB1;0.27mg/L)であった。39±0.27）ng/ml、（15.74±3.85）pg/ml、（16.47±4.75）pg/ml、（2.18±0.57）ng/ml、（0.28±0.10）ng/ml、（1.38±0.10）ng/ml、（2.39±0.27）ng/ml、（15.74±3.85）pg/ml、（16.47±4.75）pg/ml、（2.18±0.57）ng/ml、（0.28±0.10）ng/ml、（0.28±0.10）ng/ml、（1.38±0.05）ng/mlであった。54、非感染群では(62.42±14.68)mg/L、(0.89±0.21)ng/ml、(13.10±3.87)pg/ml、(14.57±3.87)pg/ml、(14.57±3.35)pg/mlであった。57±3.35）pg/ml、（1.63±0.37）ng/ml、0.09±0.01、0.83±0.24と2群間で有意差があった（<0.001）。術後6日目の臨床検査値は、感染群の方が非感染群よりも有意に高かった(<0.001)。ROC曲線分析では、PCT、IG%、IG#は脊髄損傷後の早期感染を予測でき(<0.001)、IG#の曲線下面積(AUC)はPCT、IG%に比べて有意に低かった(それぞれ0.847、0.947、0.934、<0.05)。相関分析の結果、IG%、IG#、PCTは有意に相関しており、相関係数はそれぞれ0.724、0.472(<0.001)であった。

RESULTS: At a week after operation, 33 patients occurred infection and 45 patients occurred no infection(infected group and non-infected group). All patients were followed up to no serious complications and deaths at the time of discharge. The proportion of complete injury in the infected group was significantly higher than that in the non-infected group(3.979, 0.046), and the cervical and thoracic vertebrae were more common in the infected group, and the non-infected group was mostly lumbar injury(6.226, 0.044). One day after surgery, PCT, IG%, IG# were resectively(0.71±0.10) ng/ml, 1.08±0.10, 0.20±0.05 in infected group, while in non-infected group were(0.51±0.08) ng/ml, 0.82±0.13, 0.13±0.04, there was significant difference between two groups(<0.001). At 3 days postoperatively, CRP, PCT, IL-6, IL-1β, TNF-α, IG%, IG# were resectively (80.47±15.74) mg/L, (2.39±0.27) ng/ml, (15.74±3.85) pg/ml, (16.47±4.75) pg/ml, (2.18±0.57) ng/ml, 0.28±0.10, 1.38±0.54 in injected group, while in non-infected group were(62.42±14.68) mg/L, (0.89±0.21) ng/ml, (13.10±3.87)pg/ml, (14.57±3.35) pg/ml, (1.63±0.37) ng/ml, 0.09±0.01, 0.83±0.24, there was significant difference between two groups(<0.001). At 6 days postoperatively, the laboratory parameters of the infected group were significantly higher than those of the non-infected group(<0.001). ROC curve analysis showed that PCT, IG%, and IG# could predict early infection after spinal cord injury(<0.001), and the area under the curve (AUC) of IG# was significantly lower than PCT and IG%(respectively 0.847, 0.947, 0.934, <0.05). Correlation analysis showed that IG%, IG# and PCT were significantly correlated, and the correlation coefficients were 0.724 and 0.472, respectively(<0.001).

結論:

手術後 24 時間以内の脊髄損傷患者における IG%, IG#, PCT の値の上昇は、初期の二次感染を予測するための感度と特異性が高い。術後にこれらの指標を定量化することで、感染リスクの高い患者の早期同定に役立つ。

CONCLUSIONS: The elevated levels of IG%, IG# and PCT in patients with spinal cord injury within 24 hours after surgery have high sensitivity and specificity for predicting early secondary infection. Postoperative quantification of these indicators helps early identification of patients with high risk of infection.

Copyright© 2019 by the China Journal of Orthopaedics and Traumatology Press.