Figure 7The thoracoscope is reinserted into the right chest and directed to the anterior chest wall. A retractor is inserted into the subcutaneous tunnel, and the tunnel elevated in an antero-medial direction. A tonsil vascular clamp is advanced into the subcutaneous tunnel up to the “X” where it is used to create a thoracostomy opening between the ribs at the point marked with an “X.” The tonsil clamp is withdrawn, and the appropriate size introducer is inserted into the subcutaneous tunnel with the tip facing posteriorly. The introducer is advanced into the tunnel until it is at the point marked “X.” The tip of the introducer is gently pushed through the newly created thoracostomy under thoracoscopic guidance taking care to avoid injury to the underlying structures. Once the introducer has entered the chest cavity, it is turned over so that the tip faces anteriorly. From this point onward, the tip should be kept under constant view through the thoracoscope. The introducer is slowly advanced to the mediastinum, and then by first using an anterior to posterior or “pawing” motion, the pleura and pericardium are carefully peeled off the under surface of the sternum. When a tissue plane has been established and the foamy mediastinal tissue is visualized, then the introducer may also be moved in a side to side or superior to inferior motion thereby enlarging the tunnel. At no time should this tunneling procedure be done as a blind technique. The EKG monitor should be audible to both the surgical and anesthetic staff to immediately recognize arrhythmia. As the careful dissection continues, the introducer is slowly advanced across the mediastinum and then pushed through the corresponding intercostal space on the left side at the point marked with an “X,” and then advanced out through the left subcutaneous tunnel. The pericardium and substernal tunnel are carefully inspected before proceeding to the next step. EKG = electrocardiogram. When the tip of the introducer has emerged through the X in the intercostal muscles on the left side, it is advisable to attach a bone hook, wire suture, or towel clamp to the hole in the end of the introducer and have the assistant pull in a vertical or anterior direction while the surgeon applies transverse pressure, which prevents stripping the intercostal muscles on the left side.