Anatomical basis for the development of a thoracic duct cannulation model without thoracotomy in Large White pigs

To collect lymph draining the lungs provides a useful strategy for tracing pulmonary microvascular fluid and protein biology. A methodology that allows for in vivo sampling of efferent pulmonary lymph in real-time in sheep by cannulating the thoracic duct without entering the thoracic cavity was previously established. To develop a similar thoracic duct cannulation model without thoracotomy in pigs, we investigated the anatomy of the left cervico-thoracic regions of 15 Large White (Yorkshire or Yorkshire-dominated) piglets (aged 4-7 weeks).

The thoracic duct, together with the left tracheal trunk, joined the cardiovascular system (the ampulla of the thoracic duct) at a site located craniomedial to the first rib on the left in 80 % (12/15) of the piglets.

As the location of the ampulla of the thoracic duct was consistent in most of the piglets, Large White piglets appear to be suitable for the development of a thoracic duct cannulation model without thoracotomy. The anatomical findings in this study will enable the development of further surgical procedures for cannulating the thoracic duct without thoracotomy, with minimal damage to local tissue, and without transecting any major blood vessels, nerves or muscle bellies. The establishment of a thoracic duct cannulation model for collecting in vivo, in situ efferent lymph, including pulmonary lymph, in pigs without entering the thoracic cavity would be invaluable for many immunological studies, studies on pulmonary immune responses in particular.