A Cadaveric Study of Intercostal Neurovascular Bundle Variation in Intercostal Spaces: Chest Tube Insertion Approaches
Authors: Dash Suneeti , Talley Celine , Fadanelli Kara 
Published: May 2022

Introduction/Objective

Chest tube placement is a common but often overlooked procedure. A tube thoracostomy is performed when air or fluid is present inside the pleural space causing difficulty breathing. A tube thoracostomy is typically placed in the mid‐axillary line of the 5th intercostal space (ICS) superior to the inferior rib. This approach avoids damaging the intercostal neurovascular bundle located in the superior portion of the ICS. However, if a clinician doesn't know the normal anatomy and common variations of the intercostal neurovascular bundle they can damage structures. In addition, the 4th and 6th ICS can be used to place a chest tube but are not ideal locations. Therefore, the purpose of this study is to document the intercostal neurovascular bundle in the 4th‐6th ICS at the anterior axillary and mid‐axillary line. The data will clarify how to avoid complications and explore the optimal location where chest tubes should be inserted.

Materials/Methods

Dissections were performed on formalin‐embalmed cadavers housed in the gross anatomy labs of Kansas City University. A total of 51 (n=51) cadavers were examined in this study. The cadavers were prepped using markers to mark the location of the anterior axillary and mid‐axillary lines on both sides. Afterwards, the anterior chest wall was removed by using an oscillating saw to cut through the rib cage. The neurovascular bundle was then located from the internal aspect of the anterior chest wall by identifying its location between the innermost intercostal and internal intercostal muscle. Typically, the most common order of the neurovascular bundle from superior to inferior is vein, artery, and nerve. The 4th, 5th, and 6th ICS were identified and the neurovascular bundle structures were marked using paint for photography purposes. A ruler was present in all pictures to mark the total distance of the ICS and the distance of the intercostal neurovascular bundle. Measurements of the total ICS and distance of the neurovascular bundle were taken from photographs using ImageJ software.

Results

Variations of the order of the neurovascular bundle were noted during dissection. The most common permutation was vein, artery, nerve. Measurements of the ICS showed on average that the 4th ICS was the largest.

Conclusion

The data supports conclusions drawn from past studies of the ICS and the intercostal neurovascular bundle. It is imperative for physicians to not overshoot the safe zone of the ICS when inserting a chest tube. The intercostal neurovascular bundle typically runs in the superior portion of the ICS but can present variably in the lower portion of the ICS. Clinicians should be aware of this possibility when inserting a chest tube to decrease the trauma to the anterior chest wall.

Significance/Implication

The results are noteworthy because they can help reduce the risk of complications in patients receiving a tube thoracostomy. Based on the anatomical variations of the intercostal neurovascular bundle, clinicians should be conservative when placing a chest tube and inserting it as close as possible to the inferior rib forming the ICS. Future research should focus on applying the knowledge from this study in clinical practice and evaluating if post‐procedure complications are reduced.