Treatment of Pectus Excavatum in Patients over 20 Years of Age

Introduction

The ideal time to operate on pectus excavatum (PE) using the Nuss technique is between 12 and 18 years of age, when there is still good elasticity and flexibility of the anterior thoracic wall.^1,2 The great casuistics from Nuss and other surgeons have shown that it is more difficult to bend the sternum in older patients and that they tend to have more postoperative pain and complications. However, there are few specific studies analyzing this particular group of patients, who keep coming to us for surgical treatment.^1,3

Many strong adolescents and some young adults can indeed benefit from this minimally invasive technique, and after adequate preoperative evaluation, this operation has been successfully accomplished with some modifications in the materials and techniques, including combined costocondral incisions and other tricks.^4–6 We have used some strategies that have kept the original principle of Nuss, avoiding incisions of bone and cartilage in almost all adults up to 30 years of age.

The aim of this study was to present a prospective analysis of patients with PE operated on after 20 years of age, with the Nuss technique, analyzing technical improvements, new tricks, modifications on the bar, and preliminary outcomes.

Materials and Methods

From May 2003 to September 2009, 19 patients presenting PE (group 1) were operated on at ages 20–27 years (average: 22.6 ± 1.5), including 12 men and 7 women. Associated syndromes included Marfan (2) and Ehlers-Danlos (1). Two cases had associated cardiac abnormalities: ventricular arrhythmia (1) and right bundle branch block (1). Mild functional respiratory compromise due to reduced vital capacity was evident in 2 patients. Nine presented the punch-type deformity and 10 presented the plate type. Thirteen were symmetrical and 6 were asymmetrical.

Preoperative evaluation included a multidisciplinary approach, including radiological study of the thoracic anomaly, sternal thickness, cartilage ossification, respiratory tests, cardiological, psychological, and physiatric evaluation. The latter was important to check the flexibility and expansibility of the anterior thoracic wall. Two patients aged 28 and 30 years were considered to have a thick sternum or hard, calcified anterior ribs, and hence, they were not elected for the Nuss procedure (NP), but instead had a combined Nuss-transverse-sternotomy operation and were not included in this study.

All patients had epidural continuous anesthesia for 3 days. Under general anesthesia, a mini-invasive repair was performed using a modified Nuss technique, using the 30° or 45° scope at the 6–8th right intercostal space in 9 cases and at the axilla in 10 patients. The first 3 cases demanded repeated modeling of the metallic bars because of intense pressure on the sternum, which tended to straighten the bar and to leave the extremities too prominent laterally under the skin. In the following patients, the metallic bar was prepared by hyperconvex modeling at the site expected to raise the deepest part of the sternal defect, and a more intense internal curving of the bar's extremities before its rotation (Fig. 1). Two bars were used in 1 patient with Marfan syndrome.

OPEN IN VIEWER

FIG. 1.

Diagram showing the expected final shape of the bar at the right, and how the bar should be modeled at the left. Arrows show the effects of the sternal pressure on the bar, changing its shape.

To guarantee a more constant shape and the efficiency of the prosthesis, a new metallic bar was designed with a 30% thicker central segment (two-thirds of the bar) and larger holes at the tips to facilitate fixing the extremities with sutures. These new bars could be manipulated by the same gear used to model the classical bars and were applied in the last 5 cases (patent is pending). Two stabilizers fixed the bar bilaterally to the thoracic wall in 11 cases, and only one stabilizer at the right side in 8 cases, tied with nonabsorbable and absorbable sutures. Additional stabilization was accomplished with polydioxanone or polyglicolic stitches passed percutaneously around the bar and a rib underneath, using a 1-mm grasper through a needle or using an Endoclose™ needle (Autosuture; Covidien Ltd.).

Postoperative pain management included oral tramadol, tenoxicam or ketoprofen, dipirone, occasionally ketorolac, or subcutaneous morphine. Some patients with advanced costal margin or an associated mild carinatum defect required external dynamic compression, initiated ∼6 months after the operation. Two patients with moderate scoliosis used spinal straightening devices. Normal activities were allowed after 3–4 months.

The bars were planned to be removed after 3 years. Informed consent was obtained from all patients and families. Group 1 patients were compared with a group of 26 adolescents under 20 years of age (group 2) operated on during the same period (Table 1). Statistical analysis included Student's t-test, chi-square test, and Mann–Whitney test, with alpha risk of 0.05, plotted in SPSS 17.

Results

All operations could be performed despite the more intense rigidity of the anterior thoracic wall in group 1 by using the described bar bending modifications. Operative time ranged between 65 and 130 minutes (average: 96.5 minutes). It was easier and faster in the last 5 patients who received thicker bars (range: 65–93 minutes, mean: 78 minutes, p = 0.04).

Passing the bar under the sternum requires an intercostal gap at both sides, and some force is applied along this space by rotating the bar to invert the sternal curvature. We have observed that less intercostal damage would be caused by the bar if it was rotated in a counterclockwise direction, when looking from the right side of the patient.

Using the 30° or a 45° thoracoscope at the axilla proved to be a very good access, instead of putting it near the liver, especially when the deepest point of the defect was near the xiphoid zone, at the same level as the liver. When viewing through the axilla, rotating the angle of the scope could monitor the substernal advance of the dissector, and we had more space to manipulate the dissector and the bar without dueling with the camera at the lower thoracic region. The resultant scar would be hidden at the axilla giving a better cosmetic result.

After the third postoperative day, the operations were more painful in group 1, requiring more potent analgesic drugs and for a longer period of time; however, the adults were more tolerant and complained less than most teenagers from group 2 (Table 1). Patients from group 1 were more enthusiastic to perform the operations and referred higher percentages of satisfaction with the procedures than those from group 1. There were no differences between the groups in operative times, complications, or hospitalization. One patient in group 1 had infection at the left incision and resolved clinically.

The 3 patients with dynamic external compression of the costal margin and the one with compression of a small carinatum defect succeeded after a compression period of 6–12 months.

When the bar was removed after 30 months or longer (4 patients in group 1; 3 cases in group 2), there were still no differences in these same parameters. One patient in group 2 but none in group 1 has shown a small tendency toward recurrence after bar removal, 3 years after the operation.

Discussion

The minimally invasive repair of pectus excavatum (MIRPE) using a curved substernal bar is the gold standard operation for this deformity, after the first description by Nuss. ¹ After many years of practice and testing, Nuss, as well as other colleagues following him, preferred to do the operation on patients under the age of 18 because the anterior thoracic wall is more elastic with greater postoperative comfort. However, most surgeons dealing with MIRPE are operating older patients, because they have realized that many adults could have this same operation with very satisfactory results, although with a variable degree of difficulty.^5–7

There are some reports regarding MIRPE in adults, all of them using the classical NP and the commercially available 2-mm-thick bar, and evidencing some of the expected problems.^4–8 We believe that the ideal age limit seems to be around 30–35 years of age, above which an open Ravitch, sternotomy, or a combined Nuss-Ravitch procedure is recommended. Of course there will be occasional favorable cases in older adults. Luu et al. ⁵ reported a successful NP in a 54-year-old patient.

During the operation, the sternum is initially overstretched, correcting the pectus defect by the passage of the thick metallic dissector in all cases. At this time, a firm massage of the chest and ribs increases the flexibility of the anterior thoracic wall and allows the surgeon to check the feasibility of the procedure. ¹ The problem is keeping the sternum flat over a thinner metallic bar for an additional long time. Nagasao et al. ⁹ studied the mechanical effects of the bar on the sternum and ribs, showing higher stress forces on bones and cartilages in adults, compared with teenagers.

Most casuistics include adults and asymmetrical defects as factors for higher risk of bar displacement, because of the high pressures involved between bone and steel.^4,5,9 It has been demonstrated that adults tend to have more complications and longer operative times than teenagers. ³

Considering the original management of the bar, as has been taught worldwide by Nuss for application in patients younger than 18–20 years of age, our personal experience has shown us that some modifications of the technique and material can lead to very good results in patients up to 30 years of age or perhaps older than that, comparable to those in young patients. Some authors have described complementary procedures, such as using two bars, ¹ seagull bars, ² a shorter bar, ¹⁰ metallic wires or parasternal fixations, ¹¹ sternocondral incisions, ¹² etc., aiming to reduce the reasonable rates of bar displacement or rotation.^3,6,8 Our bar bending modifications and the use of a thicker bar, coupled with two stabilizers in difficult cases, have so far resulted in no rotation of the prosthesis.

The careful selection of patients following our multidisciplinary preoperative management approach described above is important to prevent a disappointing result. The NP is not indicated for all pectus defects.^4,5 We recommend that the informed consent form includes the possibility of changing the operation into an open or combined procedure, in case an NP is selected and then the defect proves not to be correctable solely by this technique.

An annoying problem that may occur in patients presenting hard pectus defects is the necessity of repeat unrotating the bar to repeatedly adjust the curvature of the bar extremities when they have the tendency to stay too prominent under the skin laterally at the thoracic incisions. This happens because the pressure of the sternum at the central site of the curved bar bends it into a straight shape again. ⁹ The energy is transmitted to the extremities of this rigid bar, opening the original modeled shape, a fact that usually does not occur in young adolescents with a more flexible sternum bone.

Keeping the tip of the bar prominent under the skin is something to be avoided, because it is aesthetically unacceptable, can hurt the skin, cause pain, and lead to extrusion or infection of the bar. Moreover, the repeated bending and unbending of the metallic bar weakens the material in the central part of the prosthesis, reducing its efficiency in holding the sternum in position. This happened with 1 patient, for whom we had to change to another brand new bar, appropriately remodeled as described, with excellent results.

In these older patients we decided to increase the curvature of the bar extremities into an inward overcurved position while performing the initial modeling, expecting that the sternal pressure would leave them in the ideal vertical shape, as Nuss described to fit to the lateral thoracic wall. In addition, the use of the new bar with a thicker central part has allowed us a faster procedure without repeated bending of the prosthesis, not requiring an exaggerated overcurving of the bar tip.

The main concern in older patients is postoperative pain, proportional to the pressure applied to the thoracic bones.^3,6 This uncomfortable symptom is expected to happen, as it is in any major orthopedic procedure, but it should not be a contraindication for the operation. Adequate epidural blockage and further analgesic treatment can be achieved in many ways, as we have observed in our patients. The patients from group 2 received fewer analgesics for a shorter period of time than did the adults in group 1. Interestingly, the adults were more satisfied with the operation in the end than the teenagers (although without statistical significance), despite having to use more drugs to control pain. Our psychologists concluded that the adults had more desire and enthusiasm for a flat thorax, because of a longer period of low self-esteem, and were thus probably more willing to sacrifice themselves than the adolescents.

We conclude that patients with PE can be operated on during the third decade of life by the Nuss technique, facilitated by modified manipulations of the bar, thickening of the central part of the bar, and use of potent analgesics, leading to outcomes similar to those in younger patients.