Pectus excavatum, also known as funnel chest, trichterbrust, or thorax en entonnoir, is the most common anterior chest wall anomaly and results from posterior depression of the sternum and the inferior costal cartilages. The male:female ratio is 3:1, and 90% of cases are appreciated by age 1.1 The etiology of this deformity is unknown. Theories include intrauterine pressure, rickets, and abnormalities of the diaphragm.2–4 Pectus excavatum has been seen in association with agenesis of the diaphragm and congenital diaphragmatic hernia, especially after surgical repair.5 There is an association between pectus excavatum and other musculoskeletal anomalies, particularly scoliosis and Marfan's syndrome. A family history has been reported in up to 37% of patients, which may indicate a genetic predisposition.1
Surgical repair of pectus excavatum was first achieved by Meyer in 19116 and Sauerbruch in 1913.7 The method of repair has evolved over the years with increasing experience and as the primary components of the deformity became clear. Early improvements were described by Ochsner and DeBakey in 1939.8 In 1949, Ravitch described a new technique that involved excision of all the deformed costal cartilages including the perichondrium, division of the xiphoid from the sternum, division of the intercostal bundles from the sternum, and transverse sternal osteotomy, by which the sternum was angled anteriorly and secured initially with Kirschner wires and later in the series with silk sutures.9 In 1958, Welch reported his technique based on Ravitch's work,10 and this was further modified and improved, culminating in the series reported by Shamberger and Welch in 1988,11 which is the basis for the current open repair.12
Evaluation and Therapeutic Plan
Treatment of pectus excavatum has two parts: the surgical repair and an exercise and posture program. When pectus excavatum patients are evaluated clinically, they are classified as having mild, moderate, or severe deformities. Patients with mild to moderate deformities are placed on an exercise and posture program and then reevaluated at 12-month intervals. Roughly two-thirds of patients may be treated in this fashion nonoperatively. Patients with severe deformities undergo an evaluation to determine whether they are candidates for surgery. The workup includes pulmonary function studies; a cardiology evaluation, including electrocardiogram and echocardiogram; and a CT scan of the chest. The recommended technique for this CT scan is that it be performed during quiet respirations, not during maximal inspiration.
Surgical correction is recommended if the child has two or more of the following criteria: (1) progressive or symptomatic pectus excavatum, (2) restrictive lung disease as measured by pulmonary function studies, (3) a CT scan showing cardiac compression or displacement, pulmonary atelectasis, and a Haller CT index greater than 3.25, (4) cardiac abnormalities including mitral valve prolapse or bundle-branch block, and (5) recurrent pectus excavatum after a failed repair.
Surgical Technique: Open Repair
The Shamberger and Welch technique, based on that of Ravitch, is shown in Figs. 119-1, 119-2, 119-3, 119-4, 119-5, 119-6, 119-7, and 119-8.1,12 A transverse incision is made below and within the nipple lines, preferably at the site of the future inframammary crease (in females) (Fig. 119-1). With the aid of electrocautery, the skin flaps are elevated and mobilized up to the angle of Louis superiorly and down to the xiphoid inferiorly. The pectoralis major muscle is elevated off the sternum, along with some of the pectoralis minor and serratus anterior muscles. This plane can be appreciated by finding the free area just anterior to the costal cartilages at their junction with the sternum. An empty knife handle is helpful for beginning the development of this plane (Fig. 119-2). The lateral extent of the muscle dissection is defined by the costochondral junctions of the third through fifth ribs. To prevent bleeding, careful attention should be paid to avoiding injury of the intercostal bundles. The subperichondrial resection is started by incising the perichondrium anteriorly.
Incision and landmarks for open repair of pectus excavatum.
Skin flaps are elevated, and the muscle attachments to sternum are divided.
The perichondrium is divided.
The costal cartilage is removed.
After the two wedge osteotomies are created, the excess bone is removed.
Method for fixing the sternum in a forward position without the use of struts.
Technique for inserting retrosternal or presternal struts.
A parasternal catheter is placed before the muscles are reattached to the sternum.
The dissection continues in the bloodless plane between the perichondrium and the costal cartilage. Dividing the perichondrium at 90 degrees in each direction at its junction with the sternum permits visualization of the back wall of the costal cartilage (Fig. 119-3). The cartilages are separated from the junction of the sternum with a knife. One can protect the mediastinum by holding a Welch perichondrial elevator posteriorly to the cartilage during this maneuver. The divided cartilage then is held with an Allis clamp and elevated, and the dissection is continued laterally near to the bone and cartilage junction, where it is excised (Fig. 119-4). In this fashion, the bilateral third, fourth, fifth, sixth, and seventh cartilages are removed.
A sternal osteotomy is performed superior to the last deformed cartilage at the posterior angulation of the sternum (Fig. 119-5). This angle is usually located just above the insertion of the third cartilage, but occasionally it lies just above the second. Two transverse sternal osteotomies are created through the anterior cortex with a Hall air drill (Zimmer USA, Inc., Warsaw, IN) 2–4 mm apart. The small segment of anterior cortex between the two osteotomies is removed along with the underlying cancellous bone. The technique diverges at this point depending on whether or not a prosthetic strut is used to reinforce the forward position of the sternum.
The base of the sternum and the rectus muscle flap are elevated with two towel clips, and the posterior aspect of the sternum is fractured (Fig. 119-6A). The xiphoid is divided from the sternum with electrocautery, which permits entry into the retrosternal space. This step can be avoided with the use of a retrosternal strut (described below). If a strut is not used, the osteotomy is closed with heavy silk sutures while keeping the sternum elevated (Fig. 119-6B,C).
The techniques for strut placement are depicted in Fig. 119-7. Either retrosternal or presternal (Rehbein) struts may be used. The retrosternal strut is placed behind the sternum and secured to the rib ends laterally to prevent migration (Fig. 119-7B). Alternatively, Rehbein struts are inserted into the marrow cavity of the third or fourth rib ends and then joined to each other medially to create a metal arch anterior to the sternum (Fig. 119-7C). The sternum then is sewn to the arch to secure it in a forward position.
After the position of the sternum has been secured by one of the previously described methods, a closed suction drain is brought through the inferior skin flap to the left of the sternum and placed in a right parasternal location at the level of the highest costal cartilage resection (Fig. 119-8). The pectoral muscle flaps are sewn to the midline of the sternum such that the entire sternum is covered. The rectus muscle flap, if it was divided previously, is joined to the pectoral muscle flaps. The remainder of the wound is closed in layers in standard fashion with a subcuticular skin closure.
Surgical Technique: Thoracoscopic Minimally Invasive (Nuss) Repair
The surgical technique of minimally invasive pectus surgery was developed by Nuss.13,14 The procedure begins with an estimation of the length of the pectus bar that will be required for the procedure. This is accomplished by measuring the distance from the right to the left midaxillary line and then subtracting 2 cm from this measurement (Fig. 119-9). The patient is brought to the OR and placed under general endotracheal anesthesia. Placement of a thoracic epidural catheter is also very helpful and may be continued for 3–5 days postoperatively. A Foley catheter is placed, as is a nasogastric tube, and the patient receives IV antibiotic coverage. The patient is positioned with both arms abducted at the shoulder with protective gel pads.
Estimating the length of the pectus bar.
After the patient is prepped and draped, the Lorenz pectus support bar (Walter Lorenz Surgical, Jacksonville, FL) is shaped into a semicircle, save for the central 2-cm section, which remains flat. The deepest point of the pectus excavatum is marked on the patient with a marking pen. The intercostal spaces that are in the same horizontal plane as the deepest point of the pectus then are identified. These planned entry and exit points are located on either side of the sternum and should be medial to the top of the costochondral ridge. The proposed incision sites on each lateral chest wall then are identified. A thoracoscope is inserted through the right lower lateral chest wall approximately two interspaces inferior to the proposed skin incision (Fig. 119-10). With aid of the thoracoscope, a thorough inspection is made of the right hemithorax and mediastinum. Bilateral thoracic skin incisions are made, and a deep subcutaneous tunnel is raised anteriorly toward the intercostal space previously marked, medial to the top of the pectus ridge. A pocket is also created for the distal end of the pectus bar and stabilizer.
Marking the chest for thoracoscopic correction of pectus defect and placement of pectus bar.
Under direct thoracoscopic visualization, a Lorenz introducer of appropriate size for the patient is inserted through the right intercostal space at the top of the pectus ridge at the location previously marked. During this maneuver, the electrocardiogram audio signal is monitored carefully for ectopy. The pericardium is gently dissected off the undersurface of the sternum. The introducer is slowly advanced across the mediastinum under thoracoscopic guidance, with the point facing anteriorly and in direct contact with the sternum. When the substernal tunnel has been completed, the introducer is advanced through the contralateral intercostal space at the previously marked exit site and advanced out from the skin incision (Fig. 119-11).
Insertion of Lorenz introducer.
The introducer then is used to elevate the sternum. The surgeon lifts the introducer on the right side while the assistant lifts on the left side (Fig. 119-12). This lifting maneuver is repeated until the sternum has been elevated out of its depressed position, and the pectus excavatum defect has been corrected. An umbilical tape is attached to the end of the introducer, which is then pulled out, leaving umbilical tape passing through the substernal tunnel. The previously prepared pectus bar then is tied to the umbilical tape and guided through the substernal tunnel by the surgeon using the tape for traction and assisted by thoracoscopic vision (Fig. 119-13). The bar is inserted with its convexity facing posteriorly. Once the bar is in position, it is rotated 180 degrees with the bar flipper. If the bar requires further bending or adjustment, it is turned over and molded where required using the small Lorenz bar bender. If one bar is inadequate, a second bar may be inserted one interspace below or above the first one. Two bars provide a more stable correction, especially in older children. A slight overcorrection is preferable to prevent recurrence after the bar is removed.
Lorenz introducer is used to elevate the sternum to the appropriate position.
The introducer is replaced by the metal bar, and then the bar is rotated by 180 degrees.
The bar then must be stabilized. This is done by placing an inserter onto the left end of the bar and wiring it to the bar with no. 3 surgical steel wires (Fig. 119-14). Heavy absorbable 0 or 1 PDS sutures are placed around the bar and the underlying rib using an endoclose laparoscopic needle under thoracoscopic vision on the right side. Once the bar has been stabilized, the incisions are closed in layers, and the pneumothorax is evacuated using the trocar attached to suction or with a chest tube. A chest radiograph is obtained to check for residual pneumothorax.
Stabilizing the pectus bars.