Although median sternotomy incisions are widely

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1 Pectoralis Major Muscle Flap for Deep Sternal Wound Infection in Neonates Eldad Erez, MD, Miriam Katz, MD, Erez Sharoni, MD, Yaakov Katz, MD, Amos Leviav, MD, Bernardo A. Vidne, MD, and Ovadia Dagan, MD Department of Cardiothoracic Surgery and the Pediatric Cardiac Surgery Intensive Care Unit, Imaging and Roentgenology Institute, and Departments of Pediatric Anesthesia, and Plastic Surgery, Schneider Medical Center for Children, Petah-Tikva and Kaplan Medical Center, Rehovot, Israel Background. Deep sternotomy wound infections during the neonatal period, their management utilizing the pectoralis major muscle flap (PMF), and their follow-up are reported. Methods. Seven hundred-twenty consecutive pediatric cardiac operations performed from 1995 to mid 1998 in 108 neonates and 612 infants are reviewed. Nine children (1.25%), 6 neonates and 3 infants, developed deep sternotomy wound infections and underwent PMF reconstruction. The 6 neonates are reviewed. Their follow-up includes growth and development reports, physical examination, and computerized tomographic scans of the chest. Results. The incidence of sternal wound complications in our neonatal patients (5.5%, 6 of 108) was significantly higher than in the infantile group (0.5%, 3 of 612), (p , odds ratio 11.94). Five neonates were treated with a unilateral, turnover PMF reconstruction. One patient was treated by a bilateral rotational PMF. All sternal wounds healed successfully, and all patients survived. In a follow-up period, ranging from 6 to 31 months (mean 16.5 months), the growth and development of all operated neonates was as expected for their age. There were no signs of chronic sternal infection in any of them. Conclusions. Early recognition of sternal wound complications should facilitate surgical treatment. Utilizing the PMF promotes rapid wound healing and preservation of life in these severely ill neonates, with minimal developmental problems. (Ann Thorac Surg 2000;69:572 7) 2000 by The Society of Thoracic Surgeons Accepted for publication July 12, Address reprint requests to Dr Vidne, Department of Cardiothoracic Surgery, Rabin Medical Center (Beilinson Campus), Petah-Tikva, Israel. Although median sternotomy incisions are widely used in pediatric cardiac operation, there have been only a few reports dealing with the diagnosis and management of median sternotomy wound complications in children and even fewer in neonates. Deep sternal wound infection is a severe complication occurring in 0.4% to 5% of both child and adult patients, with a generally accepted rate of 1% to 2% [1 4]. The infection is defined as deep or severe, when the sternum or mediastinal structures are involved, and it demands effective surgical and antimicrobial therapy. Deep sternal wound complications in adults are routinely treated with a pectoralis major muscle flap (PMF) with good results [5]. Limited information is available regarding the treatment of pediatric poststernotomy wound complications [6 8], especially in neonates. This last group with congenital heart defects is a uniquely ill population with an immature immune system, having to cope with an early surgical intervention. Thus, their fragility in the neonatal and postoperative period makes deep sternal wound infection a life-threatening complication. In this report we review our experience with the PMF in treating mediastinal wound infection in 6 neonates during the period 1995 to mid Besides the immediate postoperative results, we also report our follow-up and delayed outcome of these neonatal patients. Patients and Methods A retrospective review of 720 consecutive pediatric cardiac surgical procedures from 1995 to mid 1998 at the Schneider Medical Center for Children was performed. All patients were computer registered. Their ages ranged from 1 day to 16 years, and they included 108 neonates and 612 infants. Of this total group, 9 developed deep sternotomy wound infection (1.25%) and were treated by wound opening, debridement, and dressing changes for several days to clean the wound prior to PMF reconstruction. Six were neonates and 3 were older children. During the period of the study, neonatal sternal closure was performed using an absorbable suture (vicryl) as opposed to sternal wire closure in older children. There was no other differences in sternal closure technique between the neonates and the older children. The neonates ranged in age from 2 to 11 days (mean 5.5 days). Their preoperative data is reported in Table 1. Two patients had mediastinitis. One underwent emergency resternotomy because of cardiac compression and low cardiac output. One patient out of 39 (2.5%) had deep sternal wound infection after delayed primary closure of the sternum. Three had undergone atrial septostomy 2000 by The Society of Thoracic Surgeons /00/$20.00 Published by Elsevier Science Inc PII S (99)

2 Ann Thorac Surg EREZ ET AL 2000;69:572 7 PMF FOR MEDIASTINAL WOUND INFECTION 573 Table 1. Preoperative Data No. Sex Age Weight Patient History Operation 1 Male 2 days 2.6 kg Preterm, TGA, S/P atrial septostomy Arterial switch 2 Male 7 days 4.1 kg TGA, S/P atrial septostomy Arterial switch 3 Female 4 days 4 kg TGA, S/P atrial septostomy Arterial switch 4 Male 11 days 3.4 kg TGA, VSD Arterial switch, VSD closure 5 Female 5 days 3 kg ASD, VSD, coarctation of aorta ASD and VSD closure, coarctation repair 6 Female 4 days 2.5 kg VSD, interrupted aortic arch VSD closure, repair of interruption ASD atrial septal defect; S/P status post; TGA transposition of the great arteries; VSD ventricular septal defect. prior to operation. All patients were treated with prostaglandin E1 and antibiotics preoperatively. The postoperative outcome of all the neonates is reported in Table 2. Their follow-up included growth and development according to the Denver development scale [9], physical examination, and helical computerized tomography (CT) of the chest. A 2 test was used to determine a 2-tailed statistically significant difference between proportions in a two-by-two table. A p value less than or equal to 0.05 was considered statistically significant. Results The incidence of sternal wound complications in our patients was significantly higher in the neonatal group (5.5%, 6 of 108) compared to older children (0.5%, 3 of 612), ( p , odds ratio 11.94). Five neonates with mediastinal wound complications were treated with unilateral, turnover PMF reconstruction. One patient was treated by bilateral, medial detachment of the PMF, joined in the midline. All sternal wounds healed successfully and all patients survived, although it was associated with a prolonged hospital stay (mean 49, range 23 to 150 days). Follow-up ranged from 6 to 31 months with an average of 16.5 months. At follow-up there were no signs of chronic sternal infection, and all wounds healed well. All patients were between 25 to 75 percentile in their weight and height nomograms and appropriately developed for their age according to the Denver development scale [9]. No limitations in upper trunk or limb movement were noted. The patient, who underwent a rotation PMF, and 2 of the 5 patients with turnover PMF repairs, had stable chest walls. Two patients had a mildly deformed anterior chest wall, with a small area of instability over the lower third of the sternum, without respiratory compromise. One patient had moderate instability of the anterior chest wall, without respiratory compromise. He will probably require reoperation to achieve chest wall stability. Comment Deep sternal wound infection after cardiac operation is a severe complication associated with increased morbidity and mortality [1, 2]. In adults there is extensive experience with sternal wound complications and their treatment by vascularized muscle flaps. Depending on the size and location of the defect, various methods of reconstruction have been described and the treatment of these complications by PMF has become routine and with good efficacy [10 14]. There is, however, scant information regarding the use of these techniques in small children, and only sporadic case reports on neonates, with no reported follow-up. Backer and colleagues [6] reported on 8 children, including 3 neonates, undergoing chest wall reconstruction. All the neonates underwent heart transplantation because of a hypoplastic left heart syndrome. Backer and colleagues used three different reconstruction approaches: unilateral PMF, bilateral PMF, and a rectus abdominis muscle flap, with 1 case of mortality in the neonatal group. Stahl and Kopf [7] reported on 4 infants, 3 of them neonates undergoing bilateral PMF with preservation of the humeral attachments; a technique used for superficial operative wound complications. The principles of deep sternal wound reconstruction are adequate debridement and resection of all infected Table 2. Postoperative Data No. Complication Time From Repair Pathogen Time to PMF Reconstruction Technique Hospital Stay Follow-up Period 1 Mediastinitis 23 days Culture ( ) 47 days Right pectoralis turnover flap 150 days 20 months 2 Mediastinitis 5 days Culture ( ) 7 days Right pectoralis turnover flap 23 days 18 months 3 Sternal wound dehiscence, 8 days Enterobacter spp. 14 days Right pectoralis turnover flap 35 days 17 months sepsis 4 Sternal wound dehiscence, 8 days Culture ( ) 14 days Left pectoralis turnover flap 28 days 31 months sepsis 5 Sternal wound dehiscence 7 days Pseudomonas 14 days Bilateral pectoralis rotation 34 days 6 months aeruginosa flaps 6 Sternal wound dehiscence 12 days Klebsiella spp. 19 days Left pectoralis turnover flap 42 days 7 months PMF pectoralis major muscle flap.

3 574 EREZ ET AL Ann Thorac Surg PMF FOR MEDIASTINAL WOUND INFECTION 2000;69:572 7 Fig 1. Patient 4, on axial thoracic computed tomographic (CT) scan after 31 months of follow-up, taken on different levels, there is (upper left) symmetric good apposition of the ossification centers at the manubrium sterni level (A), (upper right, lower left) complete fusion at the body of the sternum (B) (C), (lower right) and a single ossification center of the xiphoid process (D). In all panels the pectoralis major muscle flap (PMF) is probably not seen because it atrophied. (Arrow Split sternum with remnant PMF.) (E) The three-dimensional spiral CT reconstruction of the thorax showing the relationship of the sternal ossification centers to the thoracic components. Note the manubrium is split (arrow).

4 Ann Thorac Surg EREZ ET AL 2000;69:572 7 PMF FOR MEDIASTINAL WOUND INFECTION 575 nonviable tissue, well-vascularized coverage for optimal wound healing, anterior mediastinal protection, and chest wall stability. These conditions are all fulfilled by the PMF technique. The pectoralis major, a large flat muscle, takes part of its origin from the nearby sternum. The dominant blood supply is based on the thoracoacromial artery with a secondary supply through segmental pedicles from the internal mammary artery located 2 to 3 cm lateral to the sternum. In addition there are branches of the lateral thoracic and intercostal arteries that contribute to its blood supply. This rich blood supply has led to the development of various techniques for PMF reconstruction and even with possible preservation of form and function [13, 14]. With the lateral humeral insertion detached, and based on the internal mammary artery perforators, the muscle can be turned on itself and used to fill mediastinal defects after partial or complete sternectomy. This turnover technique was used successfully in 5 of our patients. When, in addition to this technique, the medial rib origins are also detached, the muscle can be easily moved to fill defects in the superior mediastinum, or it can be taken through a window in the anterior ribs to fill the upper chest cavity [15]. In cases of superficial sternal wound complications, the medial rib origins alone can be detached, usually bilaterally, with the two muscles joined at the midline, as was done successfully in one of our patients. Finally, Nahai and associates [14] reported a modified technique using the PMF as a turnover flap, and with preservation of the lateral one third of the muscle with its dominant vascular pedicle and motor nerves. This technique preserves the contour of the chest wall, producing a better cosmetic result, and possibly results in less growth disturbance. If the placement of one muscle does not completely close the defect, the opposite pectoralis major muscle can be similarly rotated. In adults it is well accepted that the placement of one or both pectoralis major muscles produces minimal functional disability. The positive results seen in adults for mediastinal wound reconstruction have been duplicated in single-stage operations in children. In the few reports available, it appears that the PMF works well in children, yet there are some issues of concern when dealing with small infants and neonates. Neonates with congenital heart defects are a uniquely ill population. The neonatal period is a highly vulnerable time for the infant, who is completing many of the physiologic adjustments required for extrauterine existence. Infections are a frequent cause of morbidity and mortality in the neonatal period, with up to 10% of infants being infected during delivery or during the first month of life. In addition to an immature immune system, several risk factors contribute to the frequency and severity of neonatal infections: prematurity, low birth weight, traumatic delivery, prolonged rupture of membranes, congenital defects, diagnostic and/or therapeutic procedures [16]. All these risk factors appeared in our small series of neonatal patients, and accordingly they all were treated with antibiotics preoperatively. These risk factors are most probably the main cause of the significantly higher rate of postoperative wound infections seen in neonates compared to older infants [17 19]. In this study we also found a significantly increased incidence of mediastinal wound complications in neonates compared to older children requiring PMF reconstruction. The different sternal closure technique in our group of neonates could also contribute to this high incidence of sternal complications. In addition, delayed closure of the sternum is a relatively common early postoperative technique to prevent compression of the myocardium, and in our experience has not resulted in a significant increase in sternal infection. In the vast majority of these cases, primary closure can be accomplished early, after myocardial edema has subsided. In neonates, patient size and ongoing development are important considerations in the reconstruction for deep sternotomy wound complications. The sternum and ribs are small, highly cartilaginous, and offer a poor defense against contamination. Debridement should be done conservatively, with resection of only obviously infected, nonviable tissue, minimizing future growth disturbance. All of our patients were operated on by the same plastic surgeon. The operative technique involved minimal excision, with maximum preservation of as much viable tissue as possible. This approach leads to the preservation of ossification centers and remodeling of the sternum. The PMF dissection is more difficult in neonates than in older patients due to their small size, thin and delicate nature of the neonatal musculature, less distinctive tissue planes, and the fact that the smaller vascular pedicles are less compliant. Thus minimal insults, which in adults would be insignificant, can pose a major risk to PMF survival in a suboptimal physiologic state, often characterized by some degree of cardiac failure and decreased oxygen carrying capacity of the blood. Deep sternal wound infection in neonates is a lifethreatening complication requiring prompt intervention in order to decrease mortality and shorten the need for intensive care support. During the period of the study, all patients with deep sternal wound infections underwent PMF reconstruction, and all patients survived. One patient, who was treated with a less traumatic antibiotic irrigation technique, for a long period prior to undergoing PMF reconstruction, ended up with more complications and a significantly longer hospital stay. Once these patients survive and their wounds heal, there are concerns regarding possible negative growth and development of sequelae resulting from surgical excision of the sternum and the extensive dissection and transposition of the PMF in neonates. Although our follow-up period was not very long, it covered most of the early physical development of these neonates. We found no evidence of any upper limb or upper truncal motor deficit. Using an approach which carefully excised only devitalized tissue, we found on follow-up that there is

5 576 EREZ ET AL Ann Thorac Surg PMF FOR MEDIASTINAL WOUND INFECTION 2000;69:572 7 Fig 2. Patient 1, axial computed tomographic (CT) scans of the thorax after 20 month of follow-up, at the relevant levels and by soft tissue window shows the two ossification centers at the sternal body completely separated and at (upper left) different levels (B), (upper right) prominent left upper hemithorax, and (lower left and right) prominent right lower hemithorax with rolled-up pectoralis major muscle flap (arrow). (C, D). (E) The three-dimensional spiral CT reconstruction of the thorax at follow-up showing the splitted sternum on its entire length and the paired ossification centers which are not at the same level.

6 Ann Thorac Surg EREZ ET AL 2000;69:572 7 PMF FOR MEDIASTINAL WOUND INFECTION 577 remodeling of the sternum and the PMF atrophies, resulting in a stable, well developed sternum (Fig 1A E). Unfortunately, we had 3 patients with less positive results (Fig 2A E), which could be attributed to the occurrence in these patients of more severe infections (2 had mediastinitis and 1 had sepsis). In female patients, the potential exists for disturbance of future breast development when raising a PMF, and for this a longer period of follow-up is needed. Reoperation through the reconstructed sternum has not been necessary in any of our patients, but based on our experience, this would be feasible in adults. There could possibly be an increased risk, since only a very small amount of tissue is initially placed over the mediastinum. However, on follow-up there is evidence of sternal growth with better coverage of the anterior mediastinum. From our experience, early recognition of sternal wound complications facilitates surgical reconstruction, utilizing the PMF and promoting rapid wound healing and preservation of life in these severely ill neonates, with minimal growth and development problems. References 1. Sarr MG, Gott VL, Townsend TR. Mediastinal infection after cardiac surgery. Ann Thorac Surg 1984;38: Oakley RM, Wright JE. Postoperative mediastinitis: classification and management. Ann Thorac Surg 1996;61: Pollock EMM, Ford-Jones EL, Rebeyka I, et al. Early nosocomial infections in pediatric cardiovascular surgery patients. Crit Care Med 1990;18: Edwards MS, Baker CJ. Median sternotomy wound infections in children. Pediatr Infect Dis 1983;2: Hugo NE, Sultan MR, Ascherman JA, et al. Single-stage management of 74 consecutive sternal wound complications with pectoralis major myocutaneous advancement flaps. Plast Reconstr Surg 1994;93: Backer CL, Pensler JM, Tobin GR, Mavroudis C. Vascularized muscle flaps for life threatening mediastinal wounds in children. Ann Thorac Surg 1994;57: Stahl RS, Kopf GS. Reconstruction of infant thoracic wounds. Plast Reconstr Surg 1988;82: Grant RT, Breitbart AS, Parnell V. Muscle flap reconstruction of pediatric poststernotomy wound infect. Ann Plast Surg 1997;38: Frankenburg WK, Dodds J, Archer P, et al. Denver II screening manuel. Denver: Denver Development Materials Inc, Jurkiewicz MJ, Bostwick J, Hester TR, Bishop JB, Craver J. Infected median sternotomy wounds. Ann Surg 1980;191: Arnold PG, Pairolero PC. Chest wall reconstruction experience with 100 consecutive patients. Ann Surg 1984;199: Jurkiewicz MJ, Arnold PG. The omentum: an account of its use in the reconstruction of the chest wall. Ann Surg 1977; 185: Arnold PG, Pairolero PC. Use of pectoralis major muscle flaps to repair defects of anterior chest wall. Plas Reconstr Surg 1979;63: Nahai F, Morales L, Bone DK, Bo J. Pectoralis major muscle turnover flaps for closure of the infected sternotomy wound with preservation of form and function. Plast Reconstr Surg 1982;70: De la Rocha AG, Robertson GA. Stealing the postpneumoectomy space: use of a pectoralis major myodermal flap. Ann Thorac Surg 1984;38: Behrman RE, Kliegman RM, Arvin AM, eds. Nelson textbook of pediatrics, 15th ed. Philadelphia: WB Saunders Co, Sharma LK, Sharma PK. Postoperative wound infection in a pediatric surgical service. J Pediatr Surg 1986;21: Bhattacharyya N, Kosloske AM, Macarthur C. Nosocomial infection in pediatric surgical patients: a study of 608 infants and children. J Pediatr Surg 1993;28: Davenport M, Doig CM. Wound infection in pediatric surgery: a study in 1094 neonates. J Pediatr Surg 1993;28: INVITED COMMENTARY The pectoralis major reconstruction of sternal wounds is a great life saving procedure. Nevertheless, when being performed in neonates, the resulting functional deficits and the implications on future professional careers or sport activity choices have to be taken in consideration. The preservation of the neurovascular pedicle, utilizing the thoracoacromial vessels instead of the internal mammary supply, may keep the muscle in a more anatomical and functional position. Julio Hochberg, MD Section of Plastic Surgery West Virginia University PO Box 9238 Morgantown, WV by The Society of Thoracic Surgeons /00/$20.00 Published by Elsevier Science Inc PII S (99)