RTPVs are mainly reported by radiologists, cardiologists, and surgeons. Webb, a radiologist, first reported this anomalous vein using 2-dimensional CT . Since atrial fibrillation is caused by electrical activity originating from the pulmonary veins, an accurate understanding of the pulmonary vein anatomy is important for catheter ablation therapy [6–8]. In our review of the relevant literature, the incidence of RTPV ranged from 0.28 to 9.3%. Inflow sites included the right superior pulmonary vein (RSPV), the right inferior pulmonary vein (RIPV), the LA, and the V6, with the RSPV being relatively common and the V6 being very rare (Table. 1). The location of the RTPV in relation to the right bronchus is mostly in the right intermediate bronchus. Cases such as ours, in which the RTPV runs dorsal to the right main bronchus, are very rare. Akiba et al. categorized the RTPV into six types based on their inflow site and route, and reported that most types cross the intermediate bronchus and drain into the LA or pulmonary vein . On the other hand, Miyamoto et al. classified the RTPV into four types based on the inflow site, and reported that the type that drained into the inferior pulmonary vein was the most common . Thoracic surgeons should be aware of these classifications and their frequency when performing radical esophagectomy, in which subcarinal lymph node dissection is mandatory.
Only 5 case reports in the literature have described the association of RTPV and SCLN dissection in esophagectomy [11–15] (Table 2). The operative methods included open thoracotomy, thoracoscopy, and laparoscopic transhiatal approach, and—in all cases—the RTPV could be preserved during SCLN dissection. In thoracoscopic esophagectomy, it has been reported that the prone position is better for securing a good surgical field of view to identify the RTPV because the posterior upper lobe segment (S2) is located in the dorsal side of the right upper lobe . It has been reported that retrosternal reconstruction may be a better method to avoid damaging the RTPV while pulling up the gastric tube ; we therefore chose this route. In addition, an increased incidence of incomplete fissure and displaced bronchus (DB) has been reported in patients with RTPV . It is important to recognize the presence of the RTPV preoperatively because DB may lead to difficulty during differential lung ventilation and can lead to bronchial and vascular injury . Preoperative simulation and intraoperative navigation with 3D images, which can be freely rotated and interactively visualized from any angle, are useful methods to enhance the surgeon’s understanding of the anatomy [18–20]. The use of 3D imaging enabled the preoperative diagnosis of three cases, including the present case.
An important step in SCLN dissection in thoracoscopic esophagectomy is to recognize the posterior plane of the pericardium, and release the ventral fixation of the SCLNs to the free space at the back side. This procedure is important, even in the RTPV cases. After confirming the rise of the RTPV, careful encirclement of the RTPV then results in mesenterization of the SCLN, leaving only its fixation to the right main bronchus.
In our review of the relevant literature, the mean vascular diameter was 7.0 mm at the maximum and 2.2 ± 0.72 mm at the minimum (Table 1). The diameter of the RTPV may be correlated with the amount of venous blood flow from the right upper lobe (S2) . If the RTPV is injured, hemostasis is required in the narrow surgical field due to the massive blood flow from the LA or pulmonary vein , and may cause cardiac tamponade . It is also reported that if the large RTPV is ligated, the RTPV should be reconstructed or the S2 should be resected because it is considered to drain the entire venous flow from the S2, which may cause congestion of the S2 . On the other hand, a case has been reported in which the RTPV was ligated and cut during right superior segmentectomy . Although the article did not describe the diameter of the RTPV, no serious complications occurred. It was also reported that no symptoms suggestive of upper lobe congestion occurred after ligation if the RTPV was 4.5 mm or smaller . Based on our review of the relevant literature, an RTPV larger than 4.5 mm should be noted in order to prevent injury and ligation should be avoided. The preoperative recognition of this abnormal vessel using 3D imaging was very useful for radical SCLN dissection during thoracoscopic esophagectomy.