三次元CTとインドシアニングリーン（ICG）蛍光イメージングを用いた胸腔鏡下肺区域切除術

Thoracoscopic Segmentectomy Using Three-dimensional Computed Tomography and Indocyanine-green Fluorescence Navigation

近年，末梢小型肺癌や転移性肺腫瘍などに対し区域切除術が多く行われるようになった．安全性，根治性を担保しつつ肺機能を温存することが可能であれば最適の選択肢となりうるが，そのためには手術適応の判断および実際の手術手技に十分な注意を払うことが必要である．当科では三次元CTとインドシアニングリーン（ICG）蛍光イメージングを用いた完全胸腔鏡下肺区域切除術を行っている．三次元CTは，術前に切除マージンの確保が可能かどうか予測する際に有用であり，術中には血管や気管支の解剖を把握する際に役立つ．ICG蛍光イメージングは，正確な区域間の同定を可能とし，切除マージンの確保に有用である．本術式の適応と手技上の工夫，手術成績について報告する．

Background：We investigated the feasibility and efficacy of thoracoscopic segmentectomy using 3-dimensional computed tomography （3D-CT） and indocyanine-green （ICG） fluorescence navigation.

Methods：ICG fluorescence-navigated thoracoscopic segmentectomy was performed in 149 patients during 2013 and 2017. Each patient underwent preoperative evaluation by thin-section enhanced CT, which provided 3-dimensional simulations of vascular and bronchial structures. During the procedure, low-dose ICG （0.15～0.25 mg/kg） was injected systemically after the target segmental pulmonary arteries and bronchus were divided. Under near-infrared thoracoscopic guidance, an intersegmental plane was clearly observed as a border between dark target region and bright residual region. The ICG fluorescent line was marked by electrocautery, followed by division of lung parenchyma along the line by endoscopic staples.

Results：An intersegmental line was visible in 98％ of patients by ICG fluorescence navigation. No ICG-related adverse events occurred. No operative mortality was observed and morbidity rate was 8.7％. The 5-year overall survival rate and the 5-year recurrence free probability of 101 patients with primary lung cancer were 92％ and 98％, respectively. Local recurrence at the resected site occurred in no patient with lung cancer and 1 patient with pulmonary metastasis.

Conclusion：Thoracoscopic segmentectomy using 3D-CT and ICG fluorescence navigation is a useful therapeutic option.