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A Dangerous Venous Variation in Thoracoscopic Right Lower Lobectomy
A Dangerous Venous Variation in Thoracoscopic Right Lower Lobectomy Shunsuke Endo, MD, Hiroyoshi Tsubochi, MD, Tomoyuki Nakano, MD, and Yasunori Sohara, MD Department of General Thoracic Surgery, Saitama Medical Center, Jichi Medical University, Omiya-ku, Saitama, Japan
Anatomical variations of the pulmonary vessels present a potential risk of intraoperative bleeding and damage to pulmonary circulation during pulmonary resection. We present details of a dangerous variation of the superior pulmonary vein associated with thoracoscopic right lower lobectomy that could potentially be divided if there was no preoperative foreknowledge of individual vessel configurations. (Ann Thorac Surg 2009;87:e9 –10) © 2009 by The Society of Thoracic Surgeons
T
he branching patterns of pulmonary vessels vary. Some patterns have a risk of unexpected intraoperative bleeding or damage to pulmonary circulation. We reported thoracoscopic procedures of a right lower lobectomy for a lung cancer patient with a right upper lobe vein posterior to the bronchus intermedius. Modi-
Accepted for publication August 20, 2008. Address correspondence to Dr Endo, Department of General Thoracic Surgery, Saitama Medical Center, Jichi Medical University, 1-847 Amanuma, Omiya-ku, Saitama, 330-8503, Japan; e-mail: [email protected].
fied surgical procedures based on preoperative identification of anomalous venous drainage were necessary. An 85-year-old woman with lung cancer, an adenocarcinoma, underwent a right lower lobectomy. A preoperative enhanced chest computed tomographic (CT) scan showed a right upper lobe vein posterior to the bronchus intermedius (Fig 1A). It was direct to the inferior pulmonary vein (Figs 1B–D). No other superior pulmonary vein apart from a right middle lobe vein was directed to the left atrium. Bronchoscopy showed pulsatile protrusion of the membranous portion of the bronchus intermedius caused by the venous variation. Video-assisted thoracoscopic lobectomy was performed under general anesthesia. Five accesses ports were established under selective ventilation: (1) at the third intercostal space of the anterior-axillary line, (2) at the sixth intercostal space at the posterior-axillary line, (3) at the mid-axillary line, (4) at the mid-clavicular line, and then (5) at the eighth intercostal space at the posterior-axillary line during selective ventilation. The division of the inferior pulmonary vein followed by divisions of pulmonary arteries and bronchus during the ordinal procedures for thoracoscopic lobectomy would have occluded the upper lobe venous drainage. Therefore, the divisions of the pulmonary artery and the lower bronchus were done prior to the division of the lower pulmonary vein. The posterior aspect of the major fissure, the pulmonary artery to the lower lobe, and the lower bronchus were carefully divided with mechanical staplers after identification of the venous variation. The lower Fig 1. Serial enhanced computed tomographic scans showing (A, B) a right upper lobe vein (UPV) posterior to the bronchus intermedius directed to the inferior pulmonary vein (IPV). (C) A right upper lobe vein anterior to the bronchus anterior to the bronchus is not identified. (D) The middle lobe vein (MPV) is directed to left atrium.
© 2009 by The Society of Thoracic Surgeons Published by Elsevier Inc
0003-4975/09/$36.00 doi:10.1016/j.athoracsur.2008.08.051
e10
CASE REPORT ENDO ET AL DANGEROUS PV VARIATION
pulmonary vein was divided with care taken not to damage the upper lobe venous drainage. Mediastinal nodal sampling was performed. Operation time was 125 minutes, and operative blood loss was 200 mL. The postoperative course was uneventful.
Comment Pulmonary vein variations affecting surgical procedures are usually those seen in the common pulmonary vein and the middle lobe vein into the inferior pulmonary vein or left atrium. There are only a few CT studies of the upper lobe vein posterior to the bronchus intermedius [1– 4]. The frequency is reported to range from 1.7% to 5.7%. Subgroups have been stratified by drainage pattern; and by superior pulmonary, inferior, and superior segmental vein types. The inferior vein type makes up 41.5% of all upper lobe vein variations. Using CT to identify pulmonary vessels, especially at the hila, can sometimes be very difficult because of the complex anatomy. The CT finding of an elliptical tumor behind a bronchus intermedius and the bronchoscopic finding of a membranous pulsatile protrusion in the bronchus intermedius hinted at this venous variation. The most careful operative procedure is a dissection of the posterior aspect of the major fissure. The upper lobe vein posterior to the bronchus intermedius can be divided when there is
Ann Thorac Surg 2009;87:e9 –10
another upper lobe venous drainage. In our case, however, it could not be divided because there was no other upper lobe vein. The thoracoscopic procedure was thus modified during the division of the inferior pulmonary vein. Recently, thoracoscopic lobectomy has been gaining in popularity as a potential alternative to conventional thoracotomy for early-stage lung cancer. Initial division of an inferior pulmonary vein during a right lower lobectomy, which is essential in cancer surgery, can occlude the upper lobe venous drainage. A safe and accurate right thoracoscopic lower lobectomy based on preoperative knowledge of individual vessel configurations is necessary when the chest CT shows a vessel behind the bronchus intermedius.
References 1. Asai K, Urabe N, Yajima K, Suzuki K, Kazui T. Right upper lobe venous drainage posterior to the bronchus intermedius: preoperative identification by computed tomography. Ann Thorac Surg 2005;79:1866 –71. 2. Kim JS, Choi D, Lee KS. CT of the bronchus intermedius: frequency and cause of a nodule in the posterior wall on normal scans. AJR 1995;165:1349 –52. 3. Webb WR, Hirji M, Gamsu G. Posterior wall of the bronchus intermedius: radiographic correlation. AJR 1984;141:907–11. 4. Jardin M, Remy J. Segmental bronchovascular anatomy of the lower lobes: CT analysis. AJR 1986;147:457– 68.
Anatomical variations of the pulmonary vessels present a potential risk of intraoperative bleeding and damage to pulmonary circulation during pulmonary resection. We present details of a dangerous variation of the superior pulmonary vein associated with thoracoscopic right lower lobectomy that could potentially be divided if there was no preoperative foreknowledge of individual vessel configurations. (Ann Thorac Surg 2009;87:e9 –10) © 2009 by The Society of Thoracic Surgeons
T
he branching patterns of pulmonary vessels vary. Some patterns have a risk of unexpected intraoperative bleeding or damage to pulmonary circulation. We reported thoracoscopic procedures of a right lower lobectomy for a lung cancer patient with a right upper lobe vein posterior to the bronchus intermedius. Modi-
Accepted for publication August 20, 2008. Address correspondence to Dr Endo, Department of General Thoracic Surgery, Saitama Medical Center, Jichi Medical University, 1-847 Amanuma, Omiya-ku, Saitama, 330-8503, Japan; e-mail: [email protected].
fied surgical procedures based on preoperative identification of anomalous venous drainage were necessary. An 85-year-old woman with lung cancer, an adenocarcinoma, underwent a right lower lobectomy. A preoperative enhanced chest computed tomographic (CT) scan showed a right upper lobe vein posterior to the bronchus intermedius (Fig 1A). It was direct to the inferior pulmonary vein (Figs 1B–D). No other superior pulmonary vein apart from a right middle lobe vein was directed to the left atrium. Bronchoscopy showed pulsatile protrusion of the membranous portion of the bronchus intermedius caused by the venous variation. Video-assisted thoracoscopic lobectomy was performed under general anesthesia. Five accesses ports were established under selective ventilation: (1) at the third intercostal space of the anterior-axillary line, (2) at the sixth intercostal space at the posterior-axillary line, (3) at the mid-axillary line, (4) at the mid-clavicular line, and then (5) at the eighth intercostal space at the posterior-axillary line during selective ventilation. The division of the inferior pulmonary vein followed by divisions of pulmonary arteries and bronchus during the ordinal procedures for thoracoscopic lobectomy would have occluded the upper lobe venous drainage. Therefore, the divisions of the pulmonary artery and the lower bronchus were done prior to the division of the lower pulmonary vein. The posterior aspect of the major fissure, the pulmonary artery to the lower lobe, and the lower bronchus were carefully divided with mechanical staplers after identification of the venous variation. The lower Fig 1. Serial enhanced computed tomographic scans showing (A, B) a right upper lobe vein (UPV) posterior to the bronchus intermedius directed to the inferior pulmonary vein (IPV). (C) A right upper lobe vein anterior to the bronchus anterior to the bronchus is not identified. (D) The middle lobe vein (MPV) is directed to left atrium.
© 2009 by The Society of Thoracic Surgeons Published by Elsevier Inc
0003-4975/09/$36.00 doi:10.1016/j.athoracsur.2008.08.051
e10
CASE REPORT ENDO ET AL DANGEROUS PV VARIATION
pulmonary vein was divided with care taken not to damage the upper lobe venous drainage. Mediastinal nodal sampling was performed. Operation time was 125 minutes, and operative blood loss was 200 mL. The postoperative course was uneventful.
Comment Pulmonary vein variations affecting surgical procedures are usually those seen in the common pulmonary vein and the middle lobe vein into the inferior pulmonary vein or left atrium. There are only a few CT studies of the upper lobe vein posterior to the bronchus intermedius [1– 4]. The frequency is reported to range from 1.7% to 5.7%. Subgroups have been stratified by drainage pattern; and by superior pulmonary, inferior, and superior segmental vein types. The inferior vein type makes up 41.5% of all upper lobe vein variations. Using CT to identify pulmonary vessels, especially at the hila, can sometimes be very difficult because of the complex anatomy. The CT finding of an elliptical tumor behind a bronchus intermedius and the bronchoscopic finding of a membranous pulsatile protrusion in the bronchus intermedius hinted at this venous variation. The most careful operative procedure is a dissection of the posterior aspect of the major fissure. The upper lobe vein posterior to the bronchus intermedius can be divided when there is
Ann Thorac Surg 2009;87:e9 –10
another upper lobe venous drainage. In our case, however, it could not be divided because there was no other upper lobe vein. The thoracoscopic procedure was thus modified during the division of the inferior pulmonary vein. Recently, thoracoscopic lobectomy has been gaining in popularity as a potential alternative to conventional thoracotomy for early-stage lung cancer. Initial division of an inferior pulmonary vein during a right lower lobectomy, which is essential in cancer surgery, can occlude the upper lobe venous drainage. A safe and accurate right thoracoscopic lower lobectomy based on preoperative knowledge of individual vessel configurations is necessary when the chest CT shows a vessel behind the bronchus intermedius.
References 1. Asai K, Urabe N, Yajima K, Suzuki K, Kazui T. Right upper lobe venous drainage posterior to the bronchus intermedius: preoperative identification by computed tomography. Ann Thorac Surg 2005;79:1866 –71. 2. Kim JS, Choi D, Lee KS. CT of the bronchus intermedius: frequency and cause of a nodule in the posterior wall on normal scans. AJR 1995;165:1349 –52. 3. Webb WR, Hirji M, Gamsu G. Posterior wall of the bronchus intermedius: radiographic correlation. AJR 1984;141:907–11. 4. Jardin M, Remy J. Segmental bronchovascular anatomy of the lower lobes: CT analysis. AJR 1986;147:457– 68.