A single left fourth intercostal thoracotomy approach for resolution of idiopathic chylothorax with thoracic duct ligation and pericardiectomy: a preliminary clinical study in two dogs

Abstract

Open surgical treatment of idiopathic chylothorax via thoracic duct ligation and pericardiectomy requires a lengthy procedure with two thoracotomy incisions. The objectives of this report were to describe an approach for thoracic duct ligation and pericardiectomy via a single thoracotomy at the left fourth intercostal space and to describe the clinical outcome in two dogs with idiopathic chylothorax. Dogs were prospectively enrolled in a pilot study to evaluate the clinical efficacy of thoracic duct ligation at the left fourth intercostal space, combined with subphrenic pericardiectomy performed through the same incision. Dogs had a preoperative CT lymphangiogram to evaluate the anatomy of the thoracic duct and its branching pattern prior to surgery. Recheck radiographs were performed every 2-4 weeks until effusion resolved. Pleural effusion became non-chylous by 5 days postoperatively. Pleural effusion volume decreased by day 5 postoperatively, allowing removal of thoracostomy tube and discharge from the hospital. Radiographically, effusion resolved within 6 weeks without a need for further drainage after discharge. Dogs remained symptom-free at last follow up (>11 months postoperatively). CT lymphangiograms were repeated >11 months postoperatively and revealed no recurrence of pleural effusion. No intraoperative or postoperative complications directly related to surgery were noted for either dog. Collateral lymphatic vessels were not identified on recheck CT lymphangiograms. The left fourth intercostal approach to thoracic duct ligation and pericardiectomy has potential to be a safe and effective alternative to an open approach requiring two lateral thoracotomies. Further investigation of this approach using open or minimally invasive techniques is warranted.

Keywords: fourth intercostal space; idiopathic chylothorax; pericardiectomy; pleural effusion; thoracic duct ligation.

Figure 1

Preoperative CT lymphangiogram transverse images Case #1. (A) Level of the fourth intercostal space. A single left sided thoracic duct (white arrow) is present lateral to the esophagus (black arrowhead) and dorsal to the descending aorta (star). (B) Caudal thorax. Multiple thoracic duct branches are present (between black arrows) dorsal to the aorta (star). Left is to the right of the images.

Figure 2

Intraoperative photograph Case #1. Following dissection through the mediastinum dorsal to the aorta, the thoracic duct (arrows) is easily elevated from the lateral surface of the esophagus. Mediastinal thickening was more pronounced in this case. The arrowhead indicates the phrenic nerve. Cranial is to the left of the image, dorsal is to the top of the image.

Figure 3

Intraoperative photograph at the left fourth intercostal space. Case #2: The methylene blue-stained thoracic duct can be seen (arrow) with the mediastinum on the lateral surface of the esophagus. Cranial is to the left of the image, dorsal is to the top of the image.

Figure 4

Intraoperative photograph Case #2: The thoracic duct has had clips applied and the intervening portion of the thoracic duct sealed and removed using a harmonic scalpel. The arrowhead indicates the cranial clip and the arrow indicates the caudal clips. Cranial is to the left of the image, dorsal is to the top of the image.

Figure 5

Intraoperative photograph Case #2: Subphrenic pericardiectomy was performed to remove as much pericardium as possible through access via the left intercostal thoracotomy. The arrow indicates the ligated, sealed and transected thoracic duct. Cranial is to the left of the image, dorsal is to the top of the image.

Figure 6

CT lymphangiogram transverse images of Case #1 13 months postoperatively. (A) Fourth intercostal space. The caudal most hemoclip (arrow) is lateral to the esophagus and dorsal to the aorta. (B) Fourth intercostal space 3 mm caudal to the image in panel (A). A single thoracic duct branch (arrow) can be seen lateral to the esophagus (asterisk) and dorsal to the descending aorta (star). (C) Ninth intercostal space. Three thoracic duct branches (arrows) can be seen dorsal and right lateral to the aorta. Left is to the right of the images.

Figure 7

Sagittal CT lymphangiogram images of Case # 1. (A) Preoperative image showing contrast in the region of the cisterna chyli (arrow). (B) 13 month postoperative image showing relatively unchanged abdominal lymphatics. No additional lymphatic collaterals were noted. Thoracic duct ligation site (asterisk). Cranial is to the left of the images.