Left common pulmonary venous trunk—better be careful than sorry

Abstract 

Pulmonary vein abnormalities are very commonly encountered in general thoracic surgical practice. While performing a lobectomy, ideally all the pulmonary veins should be identified before ligating the corresponding vein. Failing to recognize a common pulmonary vein may lead to an unwarranted pneumonectomy which may end up morbid for the patient. In this report, we present a patient with left lower lobe bronchiectasis who underwent a left lower lobectomy and was identified to have a common left pulmonary venous trunk intra-operatively.

Introduction 

Lobectomy is one of the most commonly performed lung surgery especially for malignancy. A sound knowledge of the pulmonary venous anatomy is needed to perform these procedures. A lot of variations can be encountered during these procedures [1]. In the left side, the most common variation noted is the common venous trunk draining the whole left lung [2]. Usually, there are 2 types of this common trunk, the longer one and the shorter one [3]. In our case, this venous trunk was present in the location of the inferior pulmonary vein and if not careful enough, the whole trunk could have been ligated which would have resulted in a more morbid pneumonectomy for the patient.

Case report

This 25-year-old lady presented with recurrent hemoptysis and on evaluation was found to have left lower lobar bronchiectasis. As the disease was localized to one lobe, it was decided to perform a left lower lobectomy. The pre-operative imaging did not report any arterial or venous abnormalities. After entering the chest through a postero-lateral thoracotomy, the lower lobar pulmonary arterial branches were ligated and divided. It was noticed that an unusually large vein was present in the fissure which looked like it was draining posteriorly into the left inferior pulmonary vein. It was also noted that the superior pulmonary vein was not present in the usual anterior location. So, the lower lobe bronchus was stapled and divided to better access the venous anatomy. On further dissection, the larger tributary was identified as the superior pulmonary vein which was coursing in the fissure and continuing posteriorly as the common trunk draining into the left atrium (Fig. 1). The tributaries draining the lower lobe were very small and were individually ligated to prevent any mishap. The patient made an uneventful recovery.

Fig. 1.

Intra-operative photograph post left lower lobectomy showing the left superior pulmonary vein (white arrow) continuing as the common trunk posteriorly near the descending aorta (blue star). Dense adhesions were there between the lower lobe and the diaphragm (yellow star). The upper lobe is indicated by a black star

Discussion

The classical teaching while performing a lobectomy is to identify all the pulmonary veins before ligating the offender [4]. In the current era of video-assisted thoracoscopic surgery (VATS), sometimes this teaching may be overlooked which can end up in disaster in patients with a single pulmonary vein [4]. The most common venous anatomy encountered is the presence of four pulmonary veins, the right superior and inferior veins (RSPV and RIPV) and the left superior and inferior pulmonary veins (LSPV and LIPV) [1]. The variations in the right side are more common and complex in nature. The most common variation in the right side is the presence of a middle pulmonary vein [1]. The most common variation in the left side is the presence of a common trunk. The incidence of left common pulmonary trunk is reported to be around 10 to 15% [2]. The superior pulmonary veins are usually anterior and the inferior pulmonary veins are posterior in location [5]. In our case, the common trunk was posterior in the usual location of the inferior pulmonary vein. If not careful enough, it could have been ligated resulting in a pneumonectomy. Usually, 3 tributaries from the lower lobe drain into the inferior pulmonary vein [6]. In our case, there was a large vein present in the fissure coursing anterior to posterior raising suspicion which was confirmed when the superior pulmonary vein was not seen anteriorly in its usual location. On further dissection, it was identified that this vein was the superior pulmonary vein and it continued posteriorly as the common trunk with 3 small tributaries draining the lower lobe joining it (Fig. 2a, b). Retrospectively, the imaging was reviewed which clearly showed this variation (Fig. 3a, b). If the knowledge of this variation was known pre-operatively, necessary precautions could have been taken during the surgery. VATS was not tried for this patient as the imaging suggested dense adhesions.

Fig. 2.

a Intra-operative photograph post left lower lobectomy showing the 3 small ligated tributaries which were draining the lower lobe (white arrows). The left superior pulmonary vein is marked with a yellow star and the left common pulmonary vein is marked with a black star. b Line diagram showing the anatomy in the previous intra-operative photograph. The left superior pulmonary vein is marked with a blue star and the left common pulmonary vein with a black star. The lower lobe tributaries are shown by the blue arrow

Fig. 3.

a CT coronal section at the level of the superior pulmonary veins entering the left atrium. The right superior pulmonary vein (yellow star) drains normally. The middle pulmonary vein (blue arrow) drains into the right superior pulmonary vein. In the left side, there was a blind ending outpouching (white arrow) where the let superior pulmonary vein usually drains. b CT coronal section at the level of the inferior pulmonary veins entering the left atrium. The right inferior pulmonary vein (blue arrow) drains normally. In the left side, a single pulmonary vein (yellow arrow) drains into the left atrium which was coming from the upper lobe, the left superior pulmonary vein continuing as the left common pulmonary vein. The tributaries to the lower lobe are not made out probably due to the lesion masking it. The bronchiectatic lung was densely adherent to the diaphragm (black star)

Conclusion

It is imperative to locate all pulmonary veins before ligating any vein during an anatomical lung resection. The radiologists have to be more vigilant in reporting pulmonary venous abnormalities as they are not uncommon. We wish to publish this case report with the radiological and intra-operative images to help the thoracic surgeon community.

Author contribution

All the authors contributed to the study conception and design. Material preparation and intra-operative photographs were taken by Nishok David. The manuscript was written by Santhosh Regini Benjamin. The surgery was done by Birla Roy Gnanamuthu.

Funding

None.

The manuscript is original and has not been submitted to any other journal for simultaneous consideration and never been published elsewhere in any form or language.

Declarations

Ethics approval

The approval of the institutional review board is not required.

Informed consent statement

Written consent for studies and publication was obtained from the patient prior to the procedure.

Conflict of interest

None of the authors declares any conflict of interest. There are no potential conflicts of interest that are directly or indirectly related to this publication, financial or otherwise.

Statement of human and animal rights

The study has been performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. This article does not contain any studies with animals performed by any of the authors.