Nuss first described the minimally invasive pectus excavatum repair in 1998. Modifications of the original repair occurred over the first decade of use, resulting in the technique depicted in Figures 140-9 to 140-14.9–12
An epidural catheter is usually placed in the operating room for perioperative pain control. Preoperative antibiotics are given and Foley catheter is placed. The patient is supine on the operating table with arms abducted.
Each side of the thorax is marked at the level of maximal pectus depth under the sternum, which is the horizontal plane for bar insertion. Measurement from right to left mid-axillary line in the horizontal plane of bar insertion is made to determine the length of the stainless steel Lorenz pectus bar (Walter Lorenz Surgical Inc., Jacksonville, FL) to be used in the operation. The bar should be 2 cm shorter than the measurement from right to left mid-axillary lines (Fig. 140-9). The intercostal spaces that are in the same horizontal plane as the deepest point of the pectus deformity are identified. The planned entry and exit points are marked, which are located on right and left sides of the sternum respectively, medial to the peak of the costochondral ridge. This allows for the pectus bar to be supported by the chest wall while elevating the sternum.9,12
Chest wall is marked bilaterally at the level of maximal pectus depth under the sternum. Measurement from right to left mid axillary line is made to determine pectus support bar length. Support bar should be 2 cm shorter than this length.
After sterile preparation and draping, the bar is bent in a convex shape, leaving a 2 to 4 cm flat middle section to support the sternum. The bar should fit the lateral chest wall on each side without compression or protrusion. If desired, the bar can be pre- shaped by the manufacturer based on the patient's CT measurements. Two small transverse incisions are made between mid- and anterior axillary lines bilaterally in the intercostal spaces at the level of maximum pectus depth (Fig. 140-10). A tunnel is created above the pectoral fascia extending anteromedially to the marked entry points of the peak of the pectus ridge bilaterally. Subcutaneous pockets are also created in the lateral portion of the incisions in order to accommodate the ends of the pectus bar and stabilizer.9–11
The intercostal space that corresponds to the level of maximum pectus depth is marked on the right and left sides of the chest for entry and exit, respectively. Bilateral transverse incisions are made at mid to anterior axillary lines in the intercostal space previously marked. Subcutaneous tunnels are made from each incision to their respective entry and exit points. A 5-mm incision is made 1 to 2 interspaces below the right incision for placement of the thoracoscope.
A small 5-mm incision is then made in the right chest 1 to 2 interspaces below the incision for insertion of the thoracoscope. A Veress needle is inserted and CO2 is insufflated to a pressure of 5 mm Hg to collapse the lung. A trocar is inserted into the right thoracic cavity and a 30-degree thoracoscope is used for visualization of the right hemithorax and mediastinum. Under direct vision, a Kelly clamp is inserted into the right thoracic cavity at the marked entry site just medial to the peak of the pectus ridge. It is important to enter the chest medial to the costochondral ridge, to allow the pectus bar to be supported by the ribs. Entering lateral to the costochondral ridge will cause the transmitted force of the bar by the sternum to be applied to the intercostal muscles without bony support, which will result in muscle tearing and bar slippage. The Lorenz introducer is then inserted into the thoracic cavity at this level and it slowly traverses the mediastinum under the peak of the sternal deformity (Fig. 140-11). During this maneuver, the electrocardiogram is monitored closely for signs of arrhythmia. The introducer is advanced slowly across the mediastinum with the point of the introducer pointing anteriorly and riding directly along the undersurface of the sternum, in the plane between the pericardium and sternum. The introducer is advanced to the contralateral intercostal space at the previously marked exit site, medial to the costochondral ridge, and out through the skin.9,12
The introducer is inserted through the right tunnel into the chest at the entry site under direct vision with the thoracoscope. It is gently advanced across the mediastinum directly under the sternum at the level of maximum pectus depression.
Once the introducer is completely across the mediastinum to the left side, it is used to elevate the sternum (Fig. 140-12). An umbilical tape, or two heavy silk ties are tied to the end of the introducer, which is slowly pulled out, across the mediastinum under direct thoracoscopic guidance (Fig. 140-13A,B). The umbilical tape remains across the substernal tunnel and is tied to the pectus bar, which has been shaped to form the patient's corrected thoracic cavity, and guided through the substernal tunnel under direct vision using the tape for traction (Fig. 140-13C). The pectus bar is inserted with the convexity facing posteriorly. Once the bar is in position across the thorax, it is rotated 180 degrees with the bar flipper (Fig. 140-13D,E). The bar should conform to the shape of the chest wall on each side, without protruding out of the skin or compressing the chest wall (Fig. 140-13F). If further bending of the bar is required, it is flipped and bent using the small Lorenz bar bender. A second bar may be required for adequate correction. This may be inserted one interspace above or below the first bar (Fig. 140-14).9,13
The introducer is advanced across the mediastinum and is used to elevate the sternum.
A. An umbilical tape is tied to the end of the introducer. B. The introducer is slowly retracted through the substernal tunnel into the right chest under direct vision, leaving the umbilical tape across the mediastinum. C. The umbilical tape is tied to the pectus support bar (shaped to the conformation of the patient's chest wall). D. Pectus bar is slowly pulled across the mediastinum into the left chest under direct vision, with the convexity of the bar facing posteriorly. E. Bar flipper is used to turn the pectus bar 180 degrees. F. The pectus bar should be positioned closely to the chest wall on either side of the thorax.
A second bar may be required for adequate correction of the pectus deformity. Inset: A stabilizer is placed at the end of the bar on the left side or bilaterally. It is secured with a number 3 surgical steel wire or heavy nonabsorbable suture.
After adequate positioning of the bar(s) for correction of the pectus deformity, bar stabilization is performed by placing a stabilizer on the left side and securing it into place with number 3 surgical steel in a figure-of-eight pattern. Alternatively a heavy nonabsorbable suture such as polypropylene is used with the titanium bar for those with metal allergy (Fig. 140-14, inset). Several heavy 0 or 1 absorbable sutures are used for pericostal suture placement to secure the bar to the underlying rib on the right side. This can be performed under direct vision with the thoracoscope. Additional absorbable 0 sutures are used to secure the fascia of the chest wall to the holes in the bar and stabilizer.9,12
Once the bars are secured in place, the incisions are closed in multiple layers. The residual pneumothorax is evacuated after the incisions are closed, by leaving the trocar in the chest, cutting the gas tubing, and placing the tubing in a bowl of saline to create a water seal. The anesthesiologist applies positive pressure ventilation until the CO2 is evacuated, which is evident by cessation of bubbling in the bowl of saline. The trocar is then removed and site closed in two layers. A chest radiograph is obtained postoperatively to evaluate for residual pneumothorax and baseline bar position.9–13