Surgical Correction of Pectus Excavatum

Surgical Correction of Pectus Excavatum

Surgical Correction of Pectus Excavatum JOE D. MORRIS, M.D., F.A.C.S. Associate Professor of Surgery (Thoracic), University of Michigan Medical School...

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Surgical Correction of Pectus Excavatum JOE D. MORRIS, M.D., F.A.C.S. Associate Professor of Surgery (Thoracic), University of Michigan Medical School, Ann Arbor

SURGICAL CORRECTION of pectus excavatum has received wide acceptance on the strength of physiological and psychological benefits gained by the patient. A variety of operations for correction of the deformity has been described. This in itself indicates that all of the problems of surgical correction of pectus excavatum have not yet been resolved. From experience gained in the surgical treatment of 30 cases of pectus excavatum an operation has evolved which in our hands has proved successful. This embodies several technical points which have previously been emphasized, not only with regard to pectus excavatum but in association with other thoracic operations. Definition Pectus excavatum, or funnel chest, is a developmental deformity of the chest characterized by posterior displacement of the sternum and lower costal cartilages. Older termlil applied to this entity include trichterbrust and chonechondrosternon. The deformity usually involves the body of the sternum, xiphoid and the lower costal cartilages bilaterally. The manubrium and the first and second anterior cartilages are normal in relationship and appearance. Starting at the manubriosternal junction the body of the'sternum slants posteriorly, the nadir of the depression being the xiphoid or the sternum just superior to it. The costal cartilages at, or medial to, the costochondral junction angle sharply posteriorly and join the deeply recessed sternum; the sharpest declivity is exhibited by the fifth and sixth cartilages. The displaced sternum may initially compress the heart against the anterior aspect of the vertebral column, but as the deformity progresses the heart is displaced into the left chest. The contour of the depression is characterized by a more gradual slope of the right costal cartilages as compared to the more vertical slant of the left costal cartilages. The deformity may be symmetrical or asymmetrical. In the latter,

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the deformity involves the right hemithorax more extensively than the left. In this circumstance, the anteroposterior diameter of the right chest may measure less than the same dimension of the left chest, possibly because of the shift of the heart into the left hemithorax. In the asymmetrical deformity, the sternum is deformed and presents a partial rotation so that the anterior surface faces to the right and the chondrosternal junctions on the right are deeper than on the left. The spiral rotation of the sternum may progress further than 90 degrees. ETIOLOGY

Although a number of valid causal factors can be cited, it is safe to say that the pathogenesis of pectus excavatum is not completely understood. Heredity plays a role in the deformity, as witnessed by the history of chest deformity existing in some other member of the immediate family of approximately 10 per cent of patients seeking treatment for pectus excavatum. The occasional existence of a pectus carinatum or pigeon breast deformity in a near relative leads to the speculation that a common denominator exists in both malformations. Three additional intrinsic factors have been stressed by various authors as the chief cause of the deformity. They are: (1) exaggerated tension of the substernal-diaphragmatic ligament; (2) overgrowth of the costal cartilages reSUlting in progressive displacement of the sternum toward the vertebral bodies; and (3) chronic airway obstruction producing retraction. 9 An extrinsic factor of causal importance is trauma which may be acute or chronic in nature. The classic example of the latter is the pectus excavatum deformity acquired by young persons in the cobblers' trade from bracing a leather-cutting tool forcibly against the lower sternum. The deformity, according to many authors, is apparent during the first year of life. Approximately half of this group of infants will show steady progression of the deformity while the remainder exhibit improvement. Hausmann 6 states that a prognostic sign is paradoxical movement or retraction which is present in those patients destined to suffer progression of the malformation. He favors operation at an early date in this group of patients before fixation of the deformity has occurred. Release of the sternodiaphragmatic ligament may be all that is necessary at this time, thereby avoiding the more extensive chondrosternoplasty. The experience in this series differs from the above observation in that the patients have ranged in age from 22 months to 22 years. One of these patients had undergone the more conservative operation of division of the sternodiaphragmatic ligament during infancy as advocated by Brown3 and represented a failure of this technique. The more extensive ehondrosternoplasty to be described was necessary to reduce the deformity.

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Fig. 1. Transverse section of thorax at level of fifth dorsal vertebra showing visceral deformity produced by pectus excavatum. 2

SYMPTOMS AND EFFECTS

Careful consideration of the anatomical nature of the deformity which is accompanied by loss of lung volume and restriction of chest wall mobility, as well as anterior-posterior compression of the base of the heart, leads to the inescapable conclusion that this deformity represents a serious encroachment upon normal cardiopulmonary physiology. It is surprising that in spite of this most children will not admit any subjective symptoms of disability. A history of recurrent respiratory infections of a severe nature during the first year of life is frequently obtainable. These episodes may be marked by noisy respirations and bronchitis. Those patients suffering from a severe degree of deformity may exhibit dyspnea and breathlessness. A systolic murmur heard in the left second anterior interspace is not unusual. Explanation may lie in the fact that compression of the great vessels at the base of the heart results in turbulence (Fig. 1). A diastolic murmur, on the contrary, points to the possibility of congenital heart disease. Adults may complain of faintness, palpitation and precordial pain of an anginal nature. The extent of the symptomatology is better appreciated after surgical correction of the deformity has been achieved. All patients notice a greater freedom of respiratory effort immediately after operation. A notable increase in stamina and endurance occurs. Parents notice that children are more vigorous and require less sleep as they fatigue less readily due to an increase in exercise tolerance. The psychological implications of this problem are not to be ignored, especially in boys. Under six years of age normal attitudes usually prevail. Older boys, seven to nine years of age, may exhibit excessive shyness

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and a cool reticence in their interpersonal relationships. This fact alone provides an indication for surgical correction of pectus excavatum before school age when possible. TECHNIQUE

Pectus excavatum has long fascinated surgeons concerned with disorders of the chest and a number of techniques for its surgical correction have been described, all championed enthusiastically by their originators. Early experience with chondrosternoplasty and external fixation at this Center was satisfactory but the operation was abandoned in favor of more conservative operations. Subsequently these proved disappointing in view of a high rate of recurrence and poor initial correction of the excavatum deformity, and the more extensive chondrosternoplasty was reinstated as the operation of choice. This was accompanied by external fixation provided by a body brace and temporary sternal traction. ANESTHESIA. Anesthesia should be conducted with the aid of an intratracheal tube, thus providing complete control of respiration by the anesthesiologist. This is important as small tears in the pleura may be encountered in the course of resecting the deformed costal cartilages. The use of noninflammable anesthetic agents permits the use of electrocoagulation assuring more perfect hemostasis. INCISION AND EXPOSURE. The midline presternal incision has been replaced by a transverse inverted V incision because of the reduced chance of keloid formation and a better cosmetic appearance of the wound. 7 The apex of the incision is curvilinear and centered at the level of the sternum midway between the manubrium and the xiphoid. The superior and inferior flaps are developed superficial to the pectoralis and rectus muscle fascia. Careful hemostasis can be best achieved using electrocoagulation which eliminates the necessity of foreign body suture material. The flap dissection should be carried in all directions to the margins of the chest wall depression. The xiphoid process is freed from the linea alba and excised. To achieve adequate exposure of the deformed costal cartilages it is necessary to reflect the medial insertion of the rectus abdominus muscle from the costal arch. The upper deformed cartilages are obscured by the origins of the pectoralis major muscles. In place of reflecting these muscles laterally for exposure, it has been simpler to make appropriate linear incisions along the path of the costal cartilages to be resected. All deformed cartilages bilaterally are freed subperichondrially from the chondrosternal junction medially to the point of angulation laterally, which is ordinarily the costochrondral junction (Fig. 2). The third cartilage may not be involved by the deformity and need not be resected in such a case. All cartilages below the level of the third cartilage must be

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Fig. 2. Composite sketch showing transverse curvilinear incision. The superior and inferior skin flaps are being retracted. Xiphoid has been excised. Deformed cartilages are being freed subperichondrially.

freed. A small periosteal elevator works well for developing the subperichondrial dissection which should be completed before resecting any one cartilage. This maintains the rigidity of the intact chest wall, facilitating the subperichondrial freeing. Care is taken to avoid violation of the underlying pleura. All deformed cartilages are then resected and blunt dissection is carried out to free the posterior aspect of the sternum from the anterior mediastinal structures. With a finger behind the sternum for support, a transverse osteotomy is carried out at the level of the sternomanubrial junction, using a small handsaw (Fig. 3). The cut is carried through both tables of bone to the posterior periosteum. Should the sternum present a deep midline groove or trough deformity, a midline sternotomy leaving the posterior peri-

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Fig. 3. Diced cartilage being packed into reconstructed perichondrial tubes. Incisions in pectoralis major have been repaired. Insert, Transverse osteotomy of sternum with use of small handsaw.

osteal membrane intact is performed in similar fashion. This permits the deformed sternum to be molded into a normal contour. THE PLASTY AND ApPLICATION OF TRACTION SLINGS. Reconstruction of the cartilages is carried out by packing the perichondrial sheaths with diced fragments of cartilage to 3 mm. in size (Fig. 3). The perichondrium is then closed with a continuous 4-0 chromic suture, making perichondrial tubes packed with malleable cartilage. These tubes furnish semirigid continuity from the costal ends to the sternal margin and promote an early recovery of chest wall stability. Gauge 22 wire is then passed around the sternum at the level of the fifth costal cartilage, avoiding the internal thoracic artery. This wire can be easily positioned by passing a large curved needle, blunt end first, alongside the sternum into the retrosternal space. A finger behind the sternum can guide the blunt end of the needle so that its eye can be visualized at the lower end of the sternum in the region of the resected xiphoid. One end of the wire can be threaded through the needle eye and the needle withdrawn, bringing one end of the wire out alongside the sternum at the desired level. The same operation is repeated on the opposite side of the sternum, withdrawing the opposite end of the wire, thus providing a wire sling around the sternum medial_to

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Fig. 4. Aluminum brace in position supporting soft anterior chest wall by elastic traction. Retrosternal drainage tube connected to water-seal drainage at negative pressure (15 cm. water).

the internal thoracic vessels. Traction on the wire sling provides complete reduction of the bony deformity. Relaxation on the wire permits the sternum to settle back, indicating that external support is mandatory for proper maintenance of the correction at this stage. Should a rotational deformity of the sternum exist, an auxiliary traction wire can be placed about the stump of a resected cartilage on the downside of the sternum so that traction may be used to reduce the rotation deformity. This has been necessary in only two cases. The incised pectoralis muscle sheath is closed with absorbable suture and the wound irrigated. DRAINAGE. Drainage is imperative in such a broad area of dissection. It is accomplished by placing a 22 F. Robinson catheter, having an open tip and several side holes, into the substernal space. The proximal end of the catheter is brought out through the end of the incision or through a small stab wound in the midline at the base of the lower wound flap. Following closure of the skin by interrupted fine silk technique, the drainage tube is connected to water-seal drainage and negative pressure equivalent to 15 cm. of water. This eliminates any hazard of pneumothorax resulting from an inadvertent opening of the pleura. ExTERNAL FIXATION. Following completion of the wound closure, a tailored brace is applied to the patient's chest (Fig. 4). The brace consists of a padded aluminum band designed to embrace the posterolateral

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portion of the upper thorax bilaterally from anterior axillary line to anterior axillary line. Across the open anterior end of the brace a double aluminum arch is secured by bolts and wing nuts at the end of the brace. The sternal traction wire is closed into a loop and adjustable elastic traction used to link the loop to the anterior arch of the brace. The direction and force of traction can be adjusted to produce the desirable correction of the deformity. COMPLICATIONS

The most serious complication seen in this series of 30 patients was one wound infection progressing to osteomyelitis of the sternum. Healing occurred slowly following adequate drainage and antibiotic therapy. This hazard stresses the importance of excellent hemostasis and the value of careful electrocoagulation. The use of nonabsorbable suture material has been avoided on the basis that it may prolong a minor infection. Overcorrection of the pectus deformity has been the only other serious complication and its prevention demands constant supervision and adjustment of the traction in the early postoperative period. Atelectasis necessitating bronchoscopy occurred in one patient in this series, and underscores the fact that problems of increased bronchial secretions may be encountered in such patients. Operation is to be avoided during any phase of a respiratory infection. SUMMARY

Correction of pectus excavatum of moderate severity has been of demonstrated value on the basis of benefits to be gained, both physiological and psychological. Dissatisfaction with the more conservative methods of surgical correction due to recurrence have resulted in the adoption o(chondrosternoplasty and reconstruction of the depressed costal cartilages. The sternal excavation is corrected by removing all deformed cartilages. The perichondrial sheaths, however, are left in place. The cartilages are diced, packed within the open sheath, and the perichondrial incision closed. Immediately after operation, costal cartilages reconstructed in this fashion are firm but not entirely stable. Temporary support to maintain full correction of the deformity is necesuntil final stability is achieved. This is readily accomplished by an adjustable body brace, featuring an anterior arch, from which wire traction is applied to the sternum. Thirty patients treated in this manner have shown satisfactory results. Wound infection with osteomyelitis of the sternum was the only serious complication. Overcorrection of the deformity occurred in one case and revision chondrosternoplasty was successful. The elective age for operation is three to five years.

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REFERENCES 1. Adkins, P. C. and Gwathmey, 0.: Pectus Excavatum: An Appraisal of Surgical Treatment. J. Thoracic Surg. 36: 714, 1958. 2. Bien, G.: Zur Anatomic und Atiologie der Trichterbrust. Beitr. Path. Anat. 52: 567,1912. 3. Brown, A. L.: Pectus Excavatum (Funnel Chest). J. Thoracic Surg. 9: 164, 1939. 4. Dailey, J. E.: Repair of Funnel Chest Using Substernal Osteoperiosteal Rib Strut; Report of Case with Four Year Follow-up. J.A.M.A. 150: 1203, 1952. 5. Gross, R. E.: Surgery of Infancy and Childhood. Philadelphia, W. B. Saunders Co., 1953. 6. Hausmann, P. F.: Surgical Management of Funnel Chest. J. Thoracic Surg. 29: 636,1955. 7. Howard, R.: Funnel Chest Experience with Treatment of 100 Cases. M. J. Australia 27: 1092, 1955. 8. Humphreys, G. H. and Connolly, J. E.: Surgical Technique for Correction of Pectus Excavatum. J. Thoracic Surg. 40: 194, 1960. 9. Lester, C. W.: Etiology and Pathogenesis of Funnel Chest, Pigeon Breast and Related Deformities of the Anterior Chest Wall. J. Thoracic Surg. 34: 1-10, 1957. 10. Lindskog, F. G. and Felton, W. L.: Considerations in Surgical Treatment of Pectus Excavatum. Ann. Surg. 142: 654, 1955. 11. Ravitch, M.: Operative Treatment of Pectus Excavatum. Ann. Surg. 129: 429, 1949. 12. Ravitch, M.: Pectus Excavatum and Heart Failure. Surgery 30: 178, 1951. 13. Welch, K. J.: Satisfactory Surgical Correction of Pectus Excavatum Deformity in Childhood. J. Thoracic Surg. 36: 697, 1958.