140: Primary Repair of Pectus Excavatum

Pectus excavatum is the most common congenital anterior chest wall defect, characterized by a posterior depression of the sternum and inferior costal cartilages. The deformity can be present at birth or develop during childhood. The sternal depression may worsen as the child grows, often peaking during pubertal growth. Incidence is reported at 1 per 1000 children. It is more common in males; the male to female ratio is 4:1. The etiology of the defect is unknown, although there is a suggestion of an intrinsic abnormality of costochondral cartilage due to the occurrence of pectus excavatum in patients with connective tissue disorders. Scoliosis is present in up to 20% of patients with pectus excavatum. In addition, a family history of pectus excavatum is present in up to 40% of patients, suggesting a genetic predisposition. Approximately one third of all children with pectus excavatum have a severe deformity that warrants evaluation for surgical repair.¹

Meyer first attempted surgical repair in 1911 and Sauerbruch in 1913.¹ In 1939, Ochsner and DeBakey reviewed the techniques of repair and reported outcomes with high morbidity and mortality.¹ Ravitch² described a technique in 1949 involving division of xiphoid from sternum, excision of deformed costal cartilages, division of intercostal bundles from sternum, transverse sternal osteotomy at junction of manubrium; angling of sternum anteriorly and suturing in position. Welch modified this technique in 1958, emphasizing the preservation of perichondrial sheaths of costal cartilages and preservation of intercostal bundles. This modified Ravitch technique is the basis of current open repair performed 50 years later.^3,4

In 1998, Nuss reported his 10-year experience with a minimally invasive technique for pectus excavatum repair. This procedure involves placement of an internal stainless steel bar to reshape the chest wall without excision of costal cartilages or sternal osteotomy.¹ The Nuss minimally invasive pectus excavatum repair has become an appealing surgical option to the traditional open repair, with excellent outcomes and a low morbidity.

Pectus excavatum includes a spectrum of severity from mild to severe. Mild to moderate deformities can benefit from an exercise and posture program, and yearly follow-up. Those patients with severe deformities should undergo a complete evaluation to define the degree of deformity and physiologic impairments which will aid in determining candidacy for surgical intervention. Approximately two-thirds of patients are treated nonoperatively.^1,4,5

Although pectus deformities may be present at birth and noticeable in early childhood, it is usually not until older childhood or teenage years that children and their parents seek evaluation and treatment. During puberty, the pectus deformity often deepens and becomes more symptomatic. Patients may describe symptoms of dyspnea on exertion, shortness of breath, exercise intolerance, air hunger, decreased endurance, and pain at the sternal border. Teenagers also present with issues with body image, which can have debilitating and life-altering psychosocial effects.^1,4–6

The operative technique performed is surgeon dependent. The minimally invasive Nuss procedure has gained widespread acceptance; however, the open technique is still performed and has comparable results. Direct comparisons of outcomes of open and minimally invasive techniques have not been performed in randomized control trials, but there have been several retrospective reviews comparing the two techniques. A meta-analysis by Nasr evaluating the published data comparing the two techniques illustrated that both open and minimally invasive repairs are acceptable techniques, with no significant difference in rate of complication, outcome, postoperative pain management, and hospital length of stay.⁷

Kelly et al. published early results of the Pectus Multicenter Study in 2007, which is a prospective study among 11 centers in the United States, attempting to compare the open and Nuss procedures with respect to complications, effect of repair on cardiopulmonary function, effect on self-image and quality of life, and patient satisfaction with pain management. The study revealed that the majority of centers were performing the Nuss procedure (284 patients) compared to open repair (43 patients). However, early results from this study demonstrated equivalent median hospital length of stay of 4 days, similar complication rates, and successful pain management in both groups.⁸

Extensive workup is performed for those patients in whom operative intervention is sought. Patient selection for operative repair is determined by performing a thorough history and physical examination to evaluate the degree of deformity and impairment. Symptoms suggesting cardiorespiratory compromise, pain, or body image issues should be investigated. On physical examination, attention to the depth of depression and associated findings of number of costal cartilages involved, rounded shoulders, protuberant abdomen (due to laxity of rectus abodminis), and presence of scoliosis should be assessed.^1,5

For those patients who appear to have a moderate-to-severe pectus excavatum deformity, further investigation is warranted. The workup includes CT scan of chest, pulmonary function testing, and echocardiogram. Echocardiogram is used to evaluate right heart function, which may be compromised due to external compression of the sternal deformity. In addition, mitral valve prolapse is associated with up to 35% of patients with pectus excavatum.^3,5 Pulmonary function testing is used to assess baseline function. It may demonstrate decrease in forced vital capacity, forced expiratory volume at 1 second, and decreased oxygen delivery, indicative of restrictive airway disease.^4,5

Chest CT allows for detailed evaluation of the degree of depression of the sternum, cardiac shift, and compression, as well as providing means to calculate the Haller index. The Haller index is a measure of pectus excavatum severity by measuring the width of the chest between the ribs at the lowest level of the pectus defect in centimeters divided by the height of the chest from the anterior spine to the back of the lowest part of the sternal defect. The quotient of this division is the Haller index. An index greater than 3.25 is considered a severe defect, warranting consideration for repair.⁴

Surgical correction of pectus excavatum is indicated with the presence of two or more of the following criteria: progressive or symptomatic pectus deformity, restrictive disease on pulmonary function testing, chest CT demonstrating cardiac compression or atelectasis, Haller index >3.25, cardiac abnormalities including mitral valve prolapse, decreased diastolic filling due to right heart compression, and recurrence after failed repair (Table 140-1).⁴ Although repair of pectus excavatum has been reported from 5 to 29 years of age, the recommended timing of repair is in the middle teenage years. During this time period, the chest wall remains malleable and allows for chest wall maturation while the support bar is still in place. Those patients who have support bars removed before puberty have an increased risk of recurrence.^9,10

If a Nuss repair is planned, the preoperative evaluation should also investigate for metal allergy, especially nickel, chromium and copper, or a family history of metal allergy. The standard Lorenz pectus bar is stainless steel, which has been shown to cause allergic reactions in those individuals with metal allergy. Those with a metal allergy and those with history of eczema should have a titanium bar and stabilizer placed instead of the standard stainless steel bar. Titanium bars are shaped by manufacturers in advance of the surgery date.⁹

The open technique described by Shamberger and Welch, is depicted in Figures 140-1 to 140-8. Preoperative antibiotics are given and continued for 24 hours postoperatively. A transverse incision is made below and within the nipple lines at the level of the inframammary crease (Fig. 140-1). Skin flaps are elevated and mobilized utilizing electrocautery to the angle of Louis superiorly and xiphoid inferiorly. The pectoral muscle flaps are elevated off the sternum and costal cartilages. This plane is defined by identifying the free area just anterior to the costal cartilages at the junction with the sternum. An empty knife handle is used to develop this plane, and muscle flap is retracted anteriorly with small right angle retractor. The muscle is dissected laterally to the level of the costochondral junctions (Fig. 140-2). The perichondrium is incised anteriorly on the third through fifth ribs, and the pectus elevator is used to preserve the perichondrial sheaths (Fig. 140-3). The cartilage is divided at the sternal junction, held with an Allis clamp, elevated, and excised from the costochondral junction. The costal cartilages of the third through seventh cartilages bilaterally are resected to the costochondral junctions (Fig. 140-4).^3,4

After removing the costal cartilages, a sternal wedge osteotomy is created above the last deformed cartilage at the posterior angulation of the sternum. The wedge osteotomy is accomplished by creating two transverse sternal osteotomies through the anterior cortex with a Hall air drill (Zimmer USA, Inc., Warsaw, IN), approximately 2 to 4 mm apart, and subsequently removing the anterior cortex and cancellous bone (Fig. 140-5).^3,4

At this point, the procedure diverges depending on whether or not prosthetic struts are used. There is no consensus on the optimal method of reconstruction. The no-strut technique is illustrated in Figure 140-6. The procedure continues by dividing the attachment of the rectus muscle to the sternum with electrocautery and elevating the sternum with towel clips. The xiphoid is divided to allow entry into the retrosternal space. The sixth and seventh perichondrial sheaths are divided in order to elevate the sternum anteriorly. The sternum is supported anteriorly by the assistant's finger, intentionally overcorrecting the sternum, and the osteotomy is closed with heavy silk sutures.⁴

The two techniques for strut placement are illustrated in Figure 140-7A–C. Either retrosternal or Rehbein (presternal) struts may be placed. If a retrosternal strut is used, the perichondrial sheath to the third or fourth rib is divided at the sternal junction. Blunt dissection is performed to develop a retrosternal space for the strut to pass. The strut is secured laterally with two pericostal sutures (Fig. 140-7B). The Rehbein struts are inserted into the marrow of the third or fourth rib and joined to each other medially over the sternum. The sternum is sewn to the arch of the struts to secure the sternum in an anterior position (Fig. 140-7C).⁴

The wound is then irrigated, and a closed suction drain is placed in a right parasternal location at the level of the highest costal cartilage resection and brought through the inferior skin flap to the left of the sternum (Fig. 140-8). The pectoral muscle flaps are sewn to the midline of the sternum. The remaining wound is closed in layers and subcuticular skin closure.³

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

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

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

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

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

Postoperative care following either open or minimally invasive pectus excavatum repair focuses around pain control and physical therapy. Postoperative pain control regimens vary among institutions, but utilize multiple drug regimens for adequate pain control. The combination of narcotics, muscle relaxants and NSAIDs are integral to a successful postoperative pain regimen. Epidural catheters are frequently used for patients undergoing pectus repair. The epidural catheter usually remains in place for 3 to 4 days, at which time the transition to oral pain medication is made. A Foley catheter is placed in the operating room and remains until the epidural is removed. Some institutions use patient-controlled analgesia instead of epidural catheters for the initial postoperative period and transition to oral pain medication on the third or fourth postoperative day. Ketorolac is an effective adjunct to the pain regimen. Attention to adequate IVF hydration and monitoring of renal function is necessary during ketorolac administration.^11,13

An incentive spirometer is used to encourage deep breathing and prevent atelectasis. Physical and occupational therapies are instituted on the first postoperative day to aid in ambulation and assistance with activities of daily living. Activity restrictions are enforced in the postoperative period to prevent bar slippage. Specific restrictions include restriction from turning on side, twisting, overhead reaching, or use of pillows or anything under shoulders.^7,11

Chest radiograph is performed postoperatively to evaluate for pneumothorax, pleural effusion, and in case of Nuss repair, bar placement. Perioperative antibiotics continue for 24 hours postoperatively. Clear liquid diet is started on the first operative day and diet is advanced as tolerated on postoperative day one.^4,7,11

Those undergoing open repair will have a closed suction catheter in the parasternal location in order to prevent fluid accumulation. This is removed when daily output is less than 15 mL over an 8-hour period.⁴ Those patients undergoing minimally invasive repair do not require drainage catheters or chest tube placement.^9,11

Length of hospitalization ranges from 3 to 6 days for both procedures. At the time of discharge, all patients are ambulating, performing activities of daily living, and on oral pain medication and bowel regimens. Pain medications are scheduled to wean off by 2 to 3 weeks postoperatively. Activity restrictions upon discharge include no sports or physical education for 6 weeks. Children may return to school after 2 to 3 weeks, however no lifting or carrying backpacks for 8 weeks postoperatively. Competitive sports are allowed after 3 months.¹¹

Following the Nuss procedure, bar removal is performed between 2 and 4 years after placement.¹¹ Rehbein or retrosternal struts are removed 6 months following open repair.⁴

Early complications of Nuss repair are outlined in Table 140-2. The most common complication is pneumothorax with spontaneous resolution. Other complications of note are atelectasis, Horner syndrome, which is a reversible side effect of epidural infusion, pneumothorax requiring chest tube decompression, medication reaction, and suture site infection. Less frequent early complications include pleural effusion, hemothorax, pneumonia, and pericarditis. Late complications (Table 140-3) include bar displacements, bar displacements requiring revision, overcorrection, bar allergy, recurrence, and bar infection.^8,11 Complications of patients undergoing open repair are outlined in Table 140-4. The most frequent complications include atelectasis, pneumothorax, Horner syndrome, wound infection, pneumonia, pleural effusion, and recurrence.^3,8

The repair of pectus excavatum in children is performed safely with no mortality and minimal morbidity with either open repair or the Nuss minimally invasive pectus excavatum repair.^3,7,8 Outcome measures of interest are adequate postoperative pain management and satisfactory surgical result. Although there is no consensus on the optimal pain regimen, multiclass drug regimens for postoperative pain management have been successful in achieving adequate pain control.^11,13 Patients and their parents report significant postoperative change in both physical and psychosocial functioning following pectus excavatum repair.⁶ Surgical repair of pectus excavatum can significantly improve body image and limitations on physical activity experienced by patients and should be considered when assessing a patient for surgical repair.⁶ Success, as measured by functional improvement, patient satisfaction, and cosmetic results, are generally reported as good to excellent by both patients and providers.^7,11 Review studies evaluating both open and minimally invasive repair demonstrate comparable outcomes with no significant difference in postoperative pain, complications, or duration of hospitalization.^7,8 Therefore, either the open or minimally invasive Nuss pectus excavatum repair can be safely performed with excellent results for those who meet criteria for surgical repair of this congenital chest wall defect.

This chapter represents a comprehensive review of both open repair and minimally invasive Nuss repair for correction of pectus excavatum. The operative detail given for both approaches is detailed and extremely helpful, given the rarity of these cases in the average thoracic surgery practice and training.