Two features of our case are of interest here: the identification of displaced B3, which stemmed from right middle lobe bronchus, and the delineation of intersegmental plane using IDT. To our best knowledge, this is the first surgical case in which the intersegmental plane was determined by IDT in a patient with lung cancer with displaced B3 and A3.
Numerous bronchial anomalies have been described previously. According to Yaginum1, the prevalence of bronchial variation is 0.76%, and the majority (84.8%) of bronchial abnormality involves right upper lobe region, however, there have been few surgical cases pertinent to B3 variation reported. This variation is considered extremely rare, especially in patients with lung cancer. One similar case was reported by Nakanishi2, in which they performed a right upper lobectomy in a patient with lung cancer and displaced B3.
Various intersegmental plane detecting methods was developed recently. Generally, the majority of them is homogeneous to the “hilum first, fissure last” technique, which is frequently applied when incomplete interlobar fissure is encountered in a lobectomy. Different from Nakanishi et. al, who used intravenous indocyanine green (ICG) with fluorescence imaging2 to recognize intersegmental plane, IDT5 is routinely performed in our center. IDT is able to distinctly delineate the proper intersegmental plane in about 10 minutes, bears no risk of anaphylactic reaction and doesn’t require fluorescence imaging.
Evidences have been gathering suggesting the equivalency between segmentectomy and lobectomy in early-stage NSCLC provided that margin handling and lymph node harvesting be executed properly6,7. It is generally accepted that segmentectomy with adequate lymph node dissection is appropriate for tumor ≤ 2 cm8. Therefore, the apical-posterior segmentectomy with systemic lymph node sampling was deemed the procedure of choice for this patient.
In conclusion, the variations of major structures similar to our case warrant particular attention. An appropriate way to address rare abnormalities is to routinize preoperative 3D-CTBA. Surgeons must stay aware of both the common and uncommon patterns of bronchus and pulmonary vessels.