Developmental Chest Wall Defects

Transcription

1 Developmental Chest Wall Defects J. L. Ehrenhaft, M.D., Nicholas P. Rossi, M.D., and M. S. Lawrence, M.D. D evelopmental anomalies and the resulting deformities of the thoracic cage have always been of great interest to pediatricians and orthopedic surgeons. Embryological and prenatal pathological investigations have clarified some of the factors involved and have in part explained some of the bizarre deformities encountered in later life. In recent years thoracic surgeons have been asked to see and treat some of these patients. More importance has been attached to the treatment of the defects, either to improve immediate function or to prevent severe disfigurement in the growing child. The factor of growth plays an important part, for the deformities may become very severe due to an imbalance created by the congenital anomaly per se or due to forces, mainly of a muscular nature, acting upon the same developmental defect. The normal growth of the thoracic cage depends upon development of several closely related bony and muscular systems, e.g., the vertebral column, spinal processes, ribs, and sternum. Abnormal muscular development of either the upper limb bud or of the diaphragm and intrinsic muscles of the chest wall can produce deformities which are progressive in the growing individual and present themselves as fixed deformities in the adult. Frequently, more than one developmental defect may be present, but if not, any single congenital anomaly may have some deforming effect on other closely associated systems. Intrathoracic visceral disease can change the contour of the developing and growing thoracic spine and rib cage. Scoliosis, congenital or due to acquired disease, if not controlled and stabilized during the growth period has a severe deforming effect upon the entire thorax, resulting at times in marked physiological changes in the respiratory and vascular systems. The possibility of alleviating deformities and preventing secondary effects resulting from them, before they become fixed when the growth period has ended, makes surgical correction at the proper time impor- From the Division of Thoracic Surgery, Department of Surgery, University of Iowa Hospitals, Iowa City, Iowa. Presented at the Second Annual Meeting of The Society of Thoracic Surgeons, Denver, Colo., Jan , THE ANNALS OF THORACIC SURGERY

2 Chest Wall Defects tant in selected patients. Some deformities defy correction, and in other, less severe ones, correction may not be necessary. In many the indication is only psychological or cosmetic, but even so if one can improve the appearance of the patient one should seriously consider it. We describe below some of the chest wall deformities which have come to our attention. Not all required surgical intervention. DEVELOPMENTAL DEFECTS OF VERTEBRAE AND RIBS Supernumerary ribs at the cervical or lumbar areas, minor deformities, fused or bifid ribs are rather common. Total absence of a single or several ribs is uncommon; it always is associated with other skeletal abnormalities of the vertebral column, such as lateral wedge vertebrae, fusion of the vertebral bodies, and other variations, which points out the close embryological developmental relationship between vertebral bodies and ribs [31. The ribs develop from the costal processes arising as paired ventral projections from the embryonic vertebral bodies (sclerotomes). During the chondrogenous period the transverse processes and the cartilaginous center of each rib are continuous, but later they are separated by a joint cavity. This process occurs independently of the development of the vertebral body itself [4]. This explains the fact that all ribs are usually present in all variations of vertebral body anomalies, but they are missing if the transverse processes are absent. J. B. C. ( ), now a 6s-year-old boy, had been seen since the age of six months with a bizarre chest deformity due to absence of ribs and lateral hemivertebrae. Examination revealed an unstable right hemithorax with two large, fused ribs acting as a strut and protruding in a grotesque manner, preventing adduction of the upper extremity. There was marked paradoxical motion of the unsupported chest cage above and below the rib struts. The scapula was carried high (Fig. 1). At the age of 3% years this deformity was partly corrected by subperiosteal resection of the protruding ribs. The chest cage was reconstructed by carrying out multiple osteotomies. Considerable cosmetic improvement and better stabilization of the chest wall was obtained. There also was some improvement of the scoliosis. The distal ends of the thoracic costal processes grow rapidly in a ventral direction during the chondrogenic stage. The contour of the cartilaginous ribs is fashioned by the heart and liver. They fuse into the sternal plate anteriorly on each side. The sternal plates unite with the sternal bands and with each other, forming the cartilaginous sternum [4]. During the mesenchymal and chondrogenic state of development, faulty fusion or anomalous chondrification may give rise to unusual fusion deformities of the ribs. S. K. ( ), a 10-year-old girl, was seen for congenital scoliosis of the thoracic spine. Multiple anomalies of the ribs with bilateral platelike fusions of VOL. 2, NO. 3, MAY,

3 EHRENHAFT, ROSSI, AND LAWRENCE A FIG. 1. A and B. Appearance of chest wall deformity and chest roentgenogram of patient J. B. C. at age 2. B FIG. 2. Fusion anomalies of ribs of patient S. K. at age 10. the ribs and hemivertebrae were resent. The motion of the thoracic cage was markedly restricted. Pulmonary Knction studies revealed inspiratory capacity was 41% of normal; expiratory reserve was 54%; vital capacity was 44%; and maximum breathing capacity was 67%. These studies indicate impairment of mobility of the thoracic cage and its effect on the respiratory function (Fig. 2). Faulty union of the sternal plates may produce an incornplete or complete bifid sternum. 386 THE ANNALS OF THORACIC SURGERY

4 Chest Wall Defects ABSENCE OF PECTORAL MUSCLES AND ANTERIOR RIB CAGE AND UPPER LIMB BUD ANOMALIES The progression of the results of this defect during the growth period has been observed in 5 of 7 patients (Table 1). The anomaly present in all of the children was the absence of the thoracic portion of the pectoralis major and the pectoralis minor muscles (Fig. 3). The defect in the chest cage was variable, but in most there was absence or TABLE 1. DEVELOPMENTAL RESULT OF ABSENCE OF THORACIC PECTORAL MUSCLES IN SEVEN CASES Age at Case Observation Chest Wall Defect Hand Deformities 1. R. B. ( ) Male 2. K. H. (Peds. O.C.) Male 3. S. B. ( ) Male 4. J. S. ( ) Male 5. R. H. ( ) Male 6. K. U. ( ) Female 7. A. S. ( ) Male 13 2% 2 weeks to 9 yr. 6 mo. to 8 yr. 4 to 8 yr. 9 mo. to 7 yr. 12 days to 6 mo.; died at 7 mo. Absent pectoralis major and minor, left; absent ribs, 2d-4th anteriorly Absent pectoralis major and minor, right; abnormal 1st & 5th ribs; mild pectus carinatum Absent pectoralis major and minor, right; absent 3d-4th ribs anteriorly; lung hernia Absent pectoralis major and minor, left; absent 3d-5th ribs anteriorly Absent pectoralis major and minor, right; absent 3d-6th ribs anteriorly; lung hernia Absent pectoralis major and minor; right hypoplastic ribs 2d4th anteriorly; breast deformity; lung hernia Absent pectoralis major and minor, right; absent 2d-5th ribs anteriorly; lung hernia Hypoplastic hand and arm; syndactylism, absence of middle phalanges Hypoplastic forearm and hand; syndactylism, absence of some phalanges and carpal bones Syndactylism, absent middle phalanges and short metacarpals VOL. 2, NO. 3, MAY,

5 EHRENHAFT, ROSSI, AND LAWRENCE A B FIG.?. Appearance of chest wall deformity and chest roentgenograms in Case? of Table 1 as seen at age 6. only rudimentary development of the anterior portions of the 2nd to 5th ribs and the corresponding rib cartilages. There was no deformity of the sternum. Some minor instability of this portion of the chest wall, which consists only of a fibromuscular membrane and skin, was present in all. Lung herniation could be demonstrated only by forceful respiratory efforts or Valsalva maneuvers. This curious anomaly, first described by Poland in 1841 [5], has not been completely explained embryologically. It has frequently and erroneously been classified as an asymmetric lateral pectus excavatum. About 10% to 20% of patients reported, and in our series 3 of 7 patients, had associated anomalies of the forearm or hand [l] (Fig. 4). Syndactylism, intrinsic anomalies of the skeleton of the hand and wrist, and hypoplasia of the forearm are part of this developmental defect. The shoulder girdle and scapula may be carried higher on the affected side. Supernumerary nipples and hypoplasia of the breast in girls are seen. The anomaly has not been reported to involve both sides. As the thoracic cage enlarges with age, the deformity becomes more pronounced, but the defect of the chest wall becomes more stable. There is no incapacity associated with it, and no surgical correction seemed necessary in our patients. The only operations were directed toward the hand deformities when present. The embryological pathology of this deformity is best explained by faulty development of part of the upper limb bud. In the 9 mm. embryo the undifferentiated mesenchyme of the limb bud which forms the pectoral muscles is located in the lower cervical region. This mass extends lower over the distal rib ends as the development progresses. In the 15 mm. embryo it splits into clavicular, pectoral, and sternal components [4]. Faulty or failure of attachment of this primitive mass to the 388 THE ANNALS OF THORACIC SURGERY

6 Chest Wall Defects FIG. 4. Right upper extremity and chest wall deformity in Case 6 of Table 1 as seen at age 7. upper rib cage and sternum (then in the process of formation) may thus explain this deformity. The unattached muscle mass disappears, and secondary atrophic changes occur in the area of the cartilaginous rib cage, which usually is covered by this now absent muscle mass. The 5th to the 8th myotomes are the ones involved. Embryological accidents in those myotomes can also explain the hand and forearm deformities. DEVELOPMENTAL DEFORMITIES OF THE STERNUM We have not had the opportunity to correct a partial or complete bifid sternum, which is indeed a rare anomaly. PECTUS EXCAVATUM The most common anterior chest wall deformity is the pectus excavatum. Opinions differ as to the cause of this anomaly. Disturbances of fetal development are cited by some, while others attribute it to mechanical factors alone. The most likely primary cause is congenitally foreshortened central tendon of the diaphragm and, at times, anomalous attachments to the lower ribs anteriorly. This restraining force is present at birth. Mechanical factors are mainly responsible for the progression of the deformity during the further growth of the thoracic cage. The point of fixation at the lower end of the sternum prevents proper respiratory excursion. The thoracic cage is maintained in the position of semiexpiration. In the infant and young child the cartilages and ribs are pliable and easily shaped by forces of motion, pressure, and growth. VOL. 2, NO. 3, MAY,

7 EHRENHAFT, ROSSI, AND LAWRENCE The apparent retraction so often mentioned in these infants is actually only a restraining of proper movement of the lower sternum in relation to the remaining, more freely mobile rib cage. After the rib cage and cartilages become less pliable, the now depressed sternum becomes permanently fixed in its lower portion. With further growth the expanding chest cage must conform to the restraint at the lower end of the sternum. The heart and mediastinal structures are in some cases compressed, or usually displaced to the left. The rib cage is forced to expand in a lateral direction, producing shortening of the anteroposterior diameter and a flattened contour. Acute inward angulation of the costal cartilages, which at times show some secondary hyperplastic changes, exaggerates the deformity. An asthenic habitus, dorsal kyphosis, forward placement of the shoulders, and protrusion of the upper abdomen are part of the clinical picture. In infants and children the deformity is usually symmetrical. During further growth severe asymmetry of the chest cage and of the sternal depression itself may result. Some deformities are mild, nonprogressive, and could not be improved greatly by operation. Others are cosmetically and psychologically unacceptable. We believe that many patients in the older age group with marked pectus excavatum deformities have physiological changes which can be demonstrated by pulmonary function studies and cardiac catheterization. Exertional fatigue and dyspnea are not uncommon in the adolescent and adult patient. At times severe intrathoracic derangement and disease result from this deformity. N. McG. ( ), a 3-year-old girl, was seen with the complaint of cough, wheezing, and frequent upper respiratory infections. A pectus excavatum was known since birth. Examination demonstrated shift of the trachea to the right, wheezes and diminished breath sounds over the entire left hemithorax, and asymmetry with evidence of some bulging of the left hemithorax. Roentgenograms revealed a severely emphysematous left lung with displacement of the mediastinal structures to the right. The right lung appeared normal. It was thought that the pulmonary changes were secondary to the unusual displacement of the mediastinal structures to the right with secondary compression of the left mainstem bronchus. Bronchoscopy revealed a narrowed and elongated left main-stem bronchus. Bronchogram showed only filling of a small amount of pulmonary tissue in the midlung field. Pulmonary angiocardiogram revealed a normal right pulmonary artery. The left pulmonary artery was considerably smaller, and all the branches were sparse and attenuated (Fig. 5). It was decided that the left lung had been destroyed due to long-standing obstructive emphysema secondary to displacement of the mediastinal structures to the right, which had resulted in stretching and compression of the left mainstem bronchus. Left exploratory thoracotomy and pneumonectomy carried out in March, 1965, corroborated this impression. The pectus excavatum has not been corrected as yet. Indications for and many different methods of correction for pectus excavatum have been described. Ravitch s method [6] is most commonly employed today and is applicable in the infant, child, and adult. 390 THE ANNALS OF THORACIC SURGERY

8 Chest Wall Defects A B C FIG. 5. (A, B) Posteroanterior and lateral chest roentgenograms demonstrating mediastinal compression and displacement to the right. Left bronchogram (C) and pulmonary arteriogram (D) demonstrating secondary changes of entire left lung. D We have operated upon 82 patients; the male-to-female ratio was 3 : 1. The youngest patient was four months, and the oldest, 32 years of age. Twenty-five patients were under 2 years old, and in most of them the deformity was very severe and the anterior chest wall was still mobile. Thirty-eight patients were between 3 and 10 years of age. The sternal deformity was already fixed in most patients in this group. The remainder of the patients were above 10 years of age, and 5 were above 20 years. We have carried out total correction in all. The partial release of the diaphragmatic attachments to the sternum in infants is an incomplete and unsatisfactory approach to the problem, in our opinion. Three patients had unsatisfactory results VOL. 2, NO. 3, MAY,

9 EHRENHAFT, ROSSI, AND LAWRENCE W FIG. 6. Schematic drawing of reconstructive method for pectus excavatum. and reoperation became necessary. The method devised and used in most of our patients varies somewhat from the ones reported by others. The lower sternum and xiphoid processes are freed from the diaphragmatic attachments. The perichondrium is stripped widely bilaterally from the third to the seventh costal cartilages. The cartilages are incised in a stair-step fashion. A transverse wedge osteotomy at the junction of the manubrium and the depressed body of the sternum is carried out. The sternal body is fixed in an anterior position with sutures at the site of osteotomy. The costal cartilages are always too long and can now be shortened and fashioned using the described stair-step method. The anterior chest cage is reconstructed with numerous fine wire sutures. (Fig. 6). This results in a nicely corrected and well-supported, stable anterior chest wall. External support by wire traction was used only in a few patients with extreme, wide, and often asymmetric deformities, and then only for a few days. This method of repair has given satisfactory cosmetic results in small children and adults. Early correction seems advisable to prevent progressive, severe deformity, and asymmetry of the entire chest cage during the active growth period. The evaluation of the postoperative cosmetic results can best be done with the aid of preoperative and postoperative casts of the anterior chest cage. We have used permanent resin casts for our comparative evaluation. PECTUS CARINATUM Anterior displacement and bulging of the sternum with an increase of the anteroposterior diameter of the thorax is frequently present in young patients with congenital cardiac or with pulmonary disease. The fixation of the sternum in an anteriorly tilted position with secon THE ANNALS OF THORACIC SURGERY

10 Chest Wall Defects dary changes of the rib cartilages is uncommon as the only anomaly. It most commonly is the counterpart of a pectus excavatum with a fixation point at the lower end of the sternum. Nonsegmentation, premature obliteration of the sternal sutures, and synostosis of all sternal segments also has been described as a possible cause of this deformity [Z]. The progressive growth causes the ribs and costal cartilages to buckle below the level of the manubrium and body of the sternum. In this manner the sternum is pushed forward. This again results in a fixed, immobile sternum with bilateral parallel depressions of the costal cartilages. The anteroposterior thoracic diameter is increased, the lateral excursion of the ribs restrained, and the lateral chest diameter decreased. The dorsum rotundum and anterior shoulder girdle displacement is present, but protrusion of the upper abdomen is not. Correction of this deformity has been performed by us in 3 patients (Fig. 7). The method of correction previously described for pectus excavatum was employed. More than one transverse osteotomy of the A B C D FIG. 7. Preoperative (top) and postoperative appearance of the chest in a 15-yearold boy with a severe pectus carinatum. VOL. 2, NO. 3, MAY,

11 EHRENHAFT, ROSSI, AND LAWRENCE sternum may be required and should be performed on the posterior surface of the sternum whenever necessary. scol.iosis Changes in the contour of the rib cage are entirely secondary to changes of the alignment of the spine. Curvatures and rotation of the spinal column, especially if they involve the thoracic spine, distort and angulate the bony cage and rib cartilages. Normal respiratory excursions of the ribs are frequently impaired. Treatment is primarily an orthopedic surgical problem. In exceptional patients some improvement in appearance can be obtained by resection and reshaping portions of the deformed bony rib cage (Fig. 8). FIG. 8. Preoperative appearance (left) and postoperatiue improvement (right) after correction of the razorback deformity. K. K. B. ( ), a 19-year-old girl with a paralytic scoliosis, had had a spinal fusion, T3 to T12, at age 12. A severe razorback deformity of the ribs to the right of the dorsal spine resulted which was cosmetically unacceptable to the patient. Partial correction of this deformity was carried out by subperiosteal resection of the 3rd to the 9th ribs posteriorly along the extent of the deformity. SUMMARY Deformities of the thoracic cage due to either congenital or acquired disease can and should be corrected in selected patients. The prevention of progressive deformities during the growth period or improvement of physiological function or appearance of the patient are the main indications. The etiology of the deformities in four different groups of patients has been discussed, and the progression of severity of the deformities during the growth period has been demonstrated. Operations 394 THE ANNALS OF THORACIC SURGERY

12 Chest Wall Defects have been advised and carried out in patients with large, unstable chest wall defects, with anomalies of the sternum, and in occasional patients with scoliotic deformities. A different method of reconstruction and stabilization of sternal deformities has been described. REFERENCES 1. Brown, J. B., and McDowell, F. Syndactylism with absence of the pectoralis major. Surgery 7:599, Carrarino, G., and Silverman, F. M. Premature obliteration of the sternal sutures and pigeon-breast deformity. Radiology 70: 532, Ehrenhaft, J. L. Development of the vertebral column as related to certain congenital and pathological changes. Surg. Gynec. Obstet. 76: 1, Keibel, F., and Mall, F. P. Human Embryology. Philadelphia: Lippincott, Pp. 331,455, Poland, A. Deficiency of the pectoral muscles. Guy. Hosp. Rep. 6:191, Ravitch, M. M. The operative treatment of pectus excavatum. Ann. Surg. 129:429, DISCUSSION DR. LYMAN A. BREWER (Los Angeles, Calif.): The authors have presented an excellent review of chest wall deformities. We have been interested in chest wall defects at the Orthopedic Hospital in Los Angeles for some time. There are three main groups: first, the sternal deformities, which I will discuss later; second, the rib and the chest wall muscle deformities, similar to the ones presented; and third, the spinal deformities. The last are traditionally the province of the orthopedic surgeon. However, the thoracic surgeon can be of great help in correcting these deformities, particularly in kyphosis where we have had excellent results with anterior spinal fusions. I hope the thoracic surgeons in this audience will be able to persuade their orthopedic confreres to make the correction on these spinal deformities a joint venture because the thoracic surgeon has a great deal to contribute to the care of these cases. Sternal deformities are the main surgical problem, as the authors have pointed out. Our own series is now over 100 cases, 90% of which have been pectus excavatum and 10% of which have been pectus carinatum. The physiological disturbances from pectus excavatum are most difficult to assess. We have done pulmonary function studies and cardiac catheterizations without detecting any marked physiological disturbance. However, we have been impressed by the increased vigor and activity, the increase in appetite, and the increase in growth that follows the repair of severe pectus excavatum. This is especially true in the age group of 4 to 6 years when the psychic factors of the deformity are minimal. Yet in the preadolescent and teenager psychic factors are tremendous and may be a main reason for operation. These teenagers shun athletics, swimming, and surfing, and attempts at psychiatric care are not accepted. Physiological impairment in the adult life is not common, and we have only seen a few patients that sought correction. Yet we are seeing more and more inadequately repaired pectus excavatum deformities that need reoperation. The surgical technique is not difficult if one sticks to certain cardinal principles. First is the complete freeing of the sternum and the deformed costal cartilages from the mediastinum, anterior chest wall, and diaphragm, as was illustrated by the authors. Second is the return of the sternum to the optimal cosmetic and functional position. Third is the firm fixation of the sternum; and fourth, which was not mentioned by the authors, is proper posture and exercise following opera tion. VOL. 2, NO. 3, MAY,

13 EHRENHAFT, ROSSI, AND LAWRENCE We have been working on our technique since World War I1 and have made a number of changes through the years. Originally, we were impressed by the tremendous pull of the pectoralis major muscle and relied on that mainly to hold the sternum. We removed the cartilages and sternum subperiosteally putting in bone chips. This gave a good correction, but there were some late depressions of the sternum. We now free the sternum up completely, dividing the superior portion of the sternum posteriorly which leaves the anterior sternal periosteum as a hinge, after the manner of Ravitch. This gives better fixation and cosmetic appearance after surgery. An innovation that we have made is posterior division of the lateral costal cartilages, which provides lateral support and mobility. More and more we are using threaded Kirschner steel wires to fix the sternum. These are left in for 6 to 12 months with excellent fixation of the sternum. They are removed under local anesthesia very easily. Finally, we use a brace postoperatively to keep the shoulders back and the carriage straight. This is quite important, because very frequently the result of the operation is jeopardized by poor carriage of the patient. Furthermore, we have incorporated a light plastic shield in front which protects these youngsters from trauma to the anterior thoracic cage. One boy who had had a recent repair of a pectus excavatum fell out of an upper bunk bed landing on top of a chair. His sternum was forced inward and he had to have a second operation. If he had had his brace on, he would have had complete protection. DR. IRVING M. MADOFF (Brookline, Mass.): I wish to discuss one technical point. I would agree first with Dr. Brewer with regard to his remarks concerning pulmonary function and cardiac catheterization. We have not been able to demonstrate any measurable change in people who had repair of pectus excavatum, although patients have reported that they have better exercise tolerance postoperatively. We have been interested, in addition, in correcting pectus carinatum. Our technique of repair consists of removing the cartilages subperichondrially from the level of the sternum laterally to the junction with osseous rib. Even with an adequate osteotomy we find that the distal end of the sternum cannot be deflected posteriorly sufficiently for a good cosmetic result; therefore, a portion of the sternum is removed to subperiosteum. This technique is not original with me. This was originally described, to me at least, by Dr. Charles Lester of New York back in 1953, and I find that it works very well. At the end of two weeks postoperatively one finds that the sternum has become firm. All the cartilages, even though they have been removed to the subperichondrium, become completely hard. Recently, in repairing a pectus excavatum, I removed the distal deformed portion of the sternum to subperiosteum rather than do a wedge osteotomy to correct the short segment. This worked very well, bone replacement was prompt, and the patient had a most satisfactory result. DR. JOSEPH GORDON (Albuquerque, N.M.): I would like to bring to your attention a procedure, sternum turnover for pectus excavatum, which was originally recommended by Dr. Juro Wada of Sapporo, Japan. The procedure was tried in patients who were over 30 years of age. The results have been satisfactory. I now have a follow-up of up to 3 years on 3 patients. One of the more characteristic findings of pectus excavatum is a density on the x-ray to the right of the midline which is usually from compressed lung and marked displacement of the heart to the left side. These changes account for some of the symptoms noted, especially in older patients. There is a great deal of narrowing of the chest seen in the lateral x-ray projection, and this is often the cause of irregularity of cardiac function and difficulty in respiratory function as well. In postoperative films much of the density which one saw before the operation disappears. One patient had a diagnosis of pneumonia made repeatedly because of the abnormality seen to the right of the heart, but the diagnosis was made only because she was seen during lower respiratory infections. 396 THE ANNALS OF THORACIC SURGERY

14 Chest Wall Defects The marked depression seen in this area before operation becomes a generous space anteriorly after surgery. It gives the heart the room that it needs for normal function, and respiratory activity is easy and comfortable. In our correction procedure, a single incision is made down the midsternum to just beyond the level of deformity. The muscles are retracted laterally, and the entire part of the deformity is resected in one piece, removed, turned over, and replaced so that it will correct the depression into more normal alignment. Fine steel wire is used to appose the rib edges and to reaffix the sternum. When the correction is done there is no risk of the sternum causing further retraction at a late postoperative period, which has been one of the faults of many of the other operative procedures. DR. RICHARD KING (Atlanta, Ga.): Dr. James E. Dailey in 1949 reported the use of a rib strut to correct pectus excavatum. I used this procedure in several cases with satisfactory results, but due to the lack of an available source of ribs and also to avoid removing a rib from the patient, I switched over to the use of a Steinmann pin or a Rush nail. The second through the seventh or eighth cartilages are removed subperichondrially, and after performing a wedge osteotomy there is adequate mobility of the sternum. The sternum is broken forward at the site of the osteotomy and the periosteum is sutured with interrupted silk. If one stops at this stage, which was recommended by Brown quite some time ago, I believe this is an inadequate procedure, because I believe some type of strut is necessary. While inserting the Steinmann pin I believe it is very helpful to insert a grooved director into the anterior mediastinum from the opposite side, so that the point of the pin is in the groove and can be pushed through to the other side without injury to any structures. For the past two years, I have felt that some type of anterior traction is necessary. One type consists of a molded, perforated Plexiglas shield which is held in place by leather straps over the shoulders as well as straps to the back. There is an adjustable bracket with two set screws, and the bracket can be placed at any level so that the adjustable rod coincides with the level of the pin under the sternum. Rubber bands are placed on the ends of the rod and pin, and this produces a more anterior projection of the sternum. The removal of the pin is an office procedure and can be done very quickly without producing any pain. The pin is removed four to six weeks after insertion. The child continues to wear the shield from six months to one year, not only for anterior protection but to help in developing a better posture. A different type of brace consists of two perpendicular metal bars with telescopic longitudinal slots. The cross bars can be adjusted so that they will coincide with the pin under the sternum. Rubber bands on each end give an added anterior projection of the sternum and I believe a better result can be obtained in this manner. When dealing with a pectus carinatum the sternum is broken backwards at the site of the wedged osteotomy and the Steinmann pin is placed anterior to the sternum through the ends of the fourth or fifth ribs, in order to hold the sternum at its new posterior level. It certainly is not necessary to remove the sternum to correct pectus carinatum. DR. DAVID H. WATERMAN (Knoxville, Tenn.): All of these comments today have been excellent contributions. I would like to mention one additional type of rather rare congenital abnormality of the sternum. This is bifid sternum, resulting from failure of the two sides of the embryonic sternum to unite. The mediastinal structures tend to herniate anteriorly, and correction of the defect is strongly indicated to protect the mediastinal structures. Surgical correction is accomplished easily by suturing the two halves of the sternum together after roughening up the edges. This should be carried out as early as possible after birth. The parents of our first case unfortunately had been

15 EHRENHAFT, ROSSI, AND LAWRENCE advised not to have the condition corrected at birth, and the baby was two months old at the time we saw her. We have seen and corrected more cases of pectus carinatum than excavatum. We have not used a strut in any of our carinatum cases but have simply resected the cartilages to subperichondrium, performed a wedge osteotomy of the sternum, and then placed a compression dressing with Elastoplast over the operative site. We have not found an additional shield necessary. In addition to the sternal prominence in pectus carinatum, there is also an unsightly flare of the costal arch. This can be corrected by removal of the protruding cartilages through separate, small, 3 or 4 cm. incisions on either side. I agree with all four of the fundamental principles that Dr. Brewer has outlined, and also agree with Dr. King that a strut is advisable in the correction of pectus excavatum. One or two stainless-steel bars can be placed beneath the sternum and above the anterior curve of the ribs on either side of the thorax. No external shield or continued external dressing is required, as nothing protrudes through the skin. Removal of the struts is easily accomplished about six weeks postoperatively by simply nicking the skin and pulling out the struts under Pentothal anesthesia. DR. RICHARD M. PETERS (Chapel Hill, N.C.): I would like to discuss briefly three things: First, I think we are probably measuring the wrong aspect of pulmonary function in patients with chest wall defects. If we measured the compliance of the chest, one would see some change postoperatively. Since this is a mechanical deformity of the chest, if we were to study chest wall mechanics, the abnormality might be identified. There are new methods of doing this which are fairly simple, and from these we may get an answer. My second point is that surgery for chest deformity is a cosmetic procedure. The modern young lady and man wear very little. A transverse incision, which is just as useful, would be much more acceptable for beach display. Third, a simple method of bracing these children, particularly the boys, is to instruct them to keep their hands in their back pockets all the time. This acts, as Dr. Brewer has suggested was important, to hold their shoulders back. You can judge how well the instructions are followed by seeing if they wear out the back pockets of their pants before the other portions. DR. EHRENHAFT: There are a few additional points I would like to make. The type of repair we have been carrying out for correction of pectus excavatum or carinatum as has been outlined has given very adequate postoperative results. External traction devices have only been employed in rare instances in very severe types of deformities, and then only for six to eight days. We have found that no further traction device was necessary thereafter. The type of Z-plasty employed and the reconstruction of the chest cage gives a very nicely fixed, reconstructed anterior thorax which maintains its contour without difficulty. On occasional patients pulmonary function studies and cardiac catheterizations have shown definite improvement following repair of the pectus excavatum. We have seen patients with superior vena cava obstruction who have had symptoms due to compression of the right ventricle and cardiac arrhythmias secondary to compression. Reconstruction of the pectus excavatum has relieved these symptoms. We have never completely excised the sternum and used it in a turned-over position. Submammary incisions are used in girls to obtain a better cosmetic result. 398 THE ANNALS OF THORACIC SURGERY