Chest Wall Reconstruction 

Updated: Jul 03, 2018
Author: David Jansen, MD, FACS; Chief Editor: Jorge I de la Torre, MD, FACS 

Overview

History of the Procedure

The history of chest wall reconstruction illustrates the challenges associated with this type of repair. In 1778, Aimar resected the first osteosarcoma of the ribs. In 1820, Cittadini reported a case of bony chest wall tumor resection. Parham, in 1899, was the first in the United States to report resection of a bony chest wall tumor involving 3 ribs. This apparently caused a pneumothorax, which was controlled with soft tissue coverage. In the early 1900s, Fell and O'Dwyer described intubation techniques and positive-pressure ventilation.[1, 2]

The image below is a postoperative photo of chest wall reconstruction.

Postoperative photo, chest wall reconstruction. Postoperative photo, chest wall reconstruction.

In 1906, Tansini used the latissimus dorsi myocutaneous flap, apparently for the first time, for coverage of radical mastectomy defects.[3] Hutchins and Campbell shared this approach.[4, 5] Graham and Singer were the first to successfully perform a pneumonectomy in the early 1930s.[6] In the 1940s, Watson and James used the fascia lata for closure of skeletal wound defects.[7] Bisgard and Swenson described the use of ribs for closure of sternectomies.[8]

Pickrell offered techniques in chest wall resection for breast cancer,[9] and Maier described his use of cutaneous flaps for patients with breast cancer postresection.[10] The 1950s and 1960s included refinement of the reconstructive techniques and the implementation of multistaged procedures. Other pioneers of mention include Arnold and Pairolero, whose studies concluded that chest wall reconstruction is safe, durable, and associated with long-term survival.[11] For the past 25 years, chest wall reconstruction has undergone a vast growth in technique and alternatives. Flaps often used for this task are the latissimus dorsi, pectoralis major, serratus anterior, rectus abdominis, external oblique, and omentum.

The congenital defect of the thorax, Poland syndrome, was described by Sir Alfred Poland in 1841.[12] He noted restricted musculature on one side of the thorax on a single autopsy. In his report entitled "Deficiency of the pectoralis muscle," he described absence of the sternocostal portion of the pectoralis major, an absent pectoralis minor, and a severely hypoplastic serratus anterior and external oblique.[12] de Haan associated the defects of Poland syndrome to the overlooked concomitant deformities of the ipsilateral upper extremity and hand.[13]

Etiology

One of the most common acquired chest wall deformities is sequela from infection. This may be the result of mediastinitis, trauma, or empyema. The resulting defects, from debridement of the chest wall or the pleural space and its contents, may require fill procedures with flaps of thoracic or abdominal origin, sterilization procedures, or collapse procedures as in thoracoplasty. Tumor radiation injury promoting scar and nonfunctional tissue also may require debridement and reconstructive measures. Resection of large chest wall, pulmonary, or mediastinal tumors, as well as defects created by trauma, may merit chest wall reconstruction.[14]

The etiology of Poland syndrome, a congenital defect of the chest wall, is unclear, yet the current theory describes hypoplasia of the ipsilateral subclavian artery in utero. The subclavian artery supply disruption sequence (SASDS) described by Parker et al illustrates the kinking of the upper extremity artery as the ribs grow forward and medially.[15] The reduction in lumen diameter and thus flow impedes distal growth, which supports the theory that more proximal blocked flow results in more severe deformity. The incidence of Poland syndrome is 1 in 30,000. The right side in Poland syndrome is affected twice as often as the left and it is considered to be autosomal dominant with low penetrance.

Möbius syndrome involves the anomalies observed in Poland syndrome in addition to bilateral facial paralysis and the inability to abduct the eyes. Möbius syndrome is observed in 1 individual per 500,000.

The etiologies of pectus excavatum and pectus carinatum are unknown. Pectus excavatum is the most common congenital anomaly of the chest (90%). The male-to-female ratio is 3:1.

Pathophysiology

The muscles of inspiration, an active action, involve primarily the diaphragm, which contracts inferiorly and creates a negative intrapleural pressure, thus inducing inhalation. Secondary muscles involved in inspiration are termed accessory muscles and are the sternocleidomastoids, which aid in raising the sternum superiorly and outward; the scalene muscles, which elevate the upper ribs; and the external intercostal muscles, which elevate all the ribs.

Expiration is a passive process. The intrinsic elasticity of the lung and musculature promotes exhalation. The muscles mentioned above relax and initiate the expiratory phase of breathing. Pulmonary function tests that measure forced expiratory volume in 1 second (FEV1), tidal volume, and the ratio of FEV1 to forced vital capacity ratio also are beneficial, yet these values are not critical in the face of mandatory surgical intervention. Lung disease takes on two broad categories, obstructive and restrictive. With obstructive disease, expiration is impeded by proximal obstruction of the bronchioles and bronchi, causing air trapping, increased functional residual capacity and residual volume, and decreased FEV1 and vital capacity.

Restrictive lung disease is an interstitial process that causes lung tissue to be less compliant, thus reducing the ability of the lung to expand. This promotes reduced lung volumes. Flail chest refers to a segment of chest wall, usually 5 cm in diameter, which loses continuity with the surrounding chest wall, resulting in a paradoxic respiratory pattern and inefficient ventilation. Adequate fixation of this segment is necessary to correct this phenomenon and restore proper respiratory physiology and ventilation.

The size of the defect above which bony stabilization is required is not clear. Two-rib segmental loss may be repaired with soft tissue reconstruction. While Dingman cautions that a 4-rib loss results in flail,[16] Arnold argues that complete sternectomy or resection of 4-6 ribs at the cartilage level does not result in flail or respiratory instability. McCormack and Picciocchi et al agree that defects less than 5 cm in diameter or resection of 3 ribs or fewer do not merit skeletal stabilization.[17, 18]

Indications

Chest wall defects are grouped into 2 general categories, acquired and congenital defects. Acquired defects include tumor (primary or recurrent), infection, radiation injury, and trauma.[19, 20] This group entails most cases that require an operative plan that balances function, durability, and aesthetics in the reconstructive effort.[21]

Congenital defects, although less common, also can be a reconstructive challenge. This article focuses on the congenital defects of Poland syndrome, pectus excavatum, and pectus carinatum.

Remember that prior to undertaking the challenge of chest wall reconstruction, the status of the pleural cavity, the requirement for skeletal support, and the extent of the soft tissue defect must be understood.

Relevant Anatomy

The paired internal thoracic arteries, the deep epigastric systems, provide the main blood supply to the ventral aspect of the chest. This system connects the major vessels of the neck to those in the groin. Many flaps are based on understanding this vascular supply. Collateral blood supply from the acromiothoracic axis is also important to recognize.

  • Latissimus dorsi muscle: The thoracodorsal artery and vein supply the anterior two thirds of the latissimus dorsi muscle (LDM). Posteriorly, the LDM relies on perforators. The thoracodorsal nerve is the only nerve supply. The LDM is the largest flat muscle, extending from the lower 6 thoracic vertebrae posteromedially, the crest of the ileum inferiorly, wrapping around anterosuperiorly with the teres major muscle to form the posterior axillary fold, and attaching to the intertubercular sulcus of the humerus.

  • Pectoralis major muscle: The pectoralis major muscle (PMM) is a fan-shaped muscle that covers the anterior superior portion of the chest and forms the anterior axillary fold. The proximal attachments are the medial half of the clavicle, the anterior surface of the sternum, the superior 6 costal cartilages, and the aponeurosis of the external oblique muscle. The distal attachments include the lateral lip of the intertubercular groove of the humerus. Blood supply includes perforators from the internal thoracic artery, intercostal arteries, and from the thoracoacromial artery. Innervation is supplied by the lateral and medial pectoral nerves.

  • Serratus anterior muscle: Located in the lateral portion of the thorax overlying the intercostals, the proximal attachments of the serratus anterior muscle (SAM) include the lateral external surfaces of ribs 1-8; the distal attachment is the anterior surface of the medial border of the scapula. Innervation and blood supply are provided via the long thoracic nerve and artery.

  • Rectus abdominis muscle: This long, broad, strap muscle is the principal vertical muscle of the anterior abdominal wall. Its origin is at the pubic symphysis and crest and its insertion is the xiphoid process and fifth to seventh costal cartilages. The innervation to the rectus abdominis muscle (RAM) includes the ventral rami of the inferior 6 thoracic nerves. The arterial supply is mainly from the inferior and superior deep epigastric arteries, supplemented by branches of the subcostal arteries.

  • External oblique muscle: The external oblique muscle (EOM) is located in the anterolateral portion of the abdominal wall. Its origin is the external surfaces of ribs 5-12 and its insertion is the linea alba, pubic tubercle, and the anterior half of the iliac crest. Its innervation is from the inferior 6 thoracic nerves, including the subcostal. The blood supply primarily involves the small arteries that arise from anterior and collateral branches of the posterior intercostal arteries in the 10th and 11th intercostal spaces and from anterior branches of the subcostal arteries.

  • Intercostal muscles: Comprising the external, internal, and innermost layers, the intercostal muscles, located between ribs, are used for inspiration and expiration. The innervation and blood supply to these muscles involve the intercostal nerves and arteries.

  • Omentum: Located intra-abdominally, the omentum drapes off of the greater curvature of the stomach. The omentum is a highly vascular and versatile sheet of adipose supplied by the gastroepiploic arteries.

Poland syndrome is characterized by abnormalities of the costal cartilages and anterior rib ends and total absence of the anterolateral ribs, resulting in herniation of the lung and deformities of the chest wall and musculature. This may manifest as absence of the sternal head of the pectoralis major (pectoralis minor may be absent), hypoplasia or aplasia of the nipple or breast, lack of subcutaneous fat and axillary hair, and shortening of the ipsilateral upper extremity along with brachysyndactyly and potential complete absence of the middle phalanges.

Pectus excavatum, also known as funnel chest, is characterized by a depressed sternum, which is held posteriorly and sunken by rib cartilage overgrowth. This explains the worsening of the condition as the child grows. Rounded sloping shoulders and mild kyphosis also are evident as well as the cardiopulmonary dysfunction that is associated with this deformity.

Pectus carinatum is due to overgrowth of the rib cartilages. This results in a protrusion of the lower sternum and xiphoid in the chondroglandular type and of the upper sternum and manubrium in the chondromanubrial type.

Contraindications

The procedure is for reconstruction, thus the contraindications are related to operative risk and flap design. The former is discussed in a separate article titled Flaps, Muscle and Musculocutaneous Flaps, and the latter is discussed in the Surgical Therapy section.

 

Workup

Laboratory Studies

Obtain routine preoperative studies.

Imaging Studies

Obtain baseline chest radiographs. Consider performing a CT scan.

Other Tests

To successfully perform chest wall reconstruction, a good understanding of the mechanics of breathing and the baseline preoperative pulmonary status are necessary.

 

Treatment

Surgical Therapy

Specific surgical strategies are discussed in the sections below.

Closure of Postpneumonectomy Empyema Cavities

Miller and colleagues have devised a protocol for achieving complete flap closure of empyema cavities.[22] They support administration of antibiotics, entry into the chest through the original incision, and wide debridement. They also support the identification of bronchopleural fistulas (see the images below), their closure with an omental flap, and obliteration of the pleural cavity with appropriate muscle flaps starting with the LDM first, SAM second, PMM third, omentum fourth, and the RAM as the last choice.

Right lateral photo of a patient who underwent pne Right lateral photo of a patient who underwent pneumonectomy, which was complicated by a bronchopleural cutaneous fistula. The photograph is of the fistula tract.
Fistulogram. Fistulogram.

Arnold and Pairolero have created a treatment similar to Miller's, using the SAM as their first choice; however, they disagree with the necessity of completely obliterating the pleural cavity.[23] Bronchopleural fistulas were packed with muscle and frequent moist dressing changes were instituted. The chest was closed secondarily.

Failed extrathoracic flaps for bronchopleural fistulas often merit free flap transfers. Hammond et al reconstructed complex intrathoracic defects with several free flaps (ie, LDM, RAM, omentum) anastomosed to the thoracodorsal, common carotid, or transverse cervical artery and vein.[24]

Butler et al have used AlloDerm over lung with flap reconstruction for contaminated wounds of the chest.[25] These wounds cannot be covered with prosthetic mesh; thus, AlloDerm (which is decellularized human cadaveric dermis) was used. It becomes vascularized and remodeled into autologous tissue after implantation.

Closure of postpneumonectomy empyema cavities also can be achieved by thoracoplasty. This procedure involves the resection of multiple ribs to allow the collapse of the chest wall and obliterate the cavity. Thoracoplasty initially was used in the treatment of active tuberculosis in the preantibiotic era and later was applied to nontuberculous postpneumonectomy empyemas. Thoracoplasty has been controversial because of the more appealing nonmutilating techniques, such as pedicled muscle transplants and open-space sterilization.

Thoracoplasty is reserved for instances when pedicled muscle flaps are unavailable (divided or devascularized) or when the empyema is chronic and caused by antibiotic-resistant organisms. Gregoire et al presented data that support thoracoplasty for patients with chronic postpneumonectomy empyemas, resulting in an excellent outcome.[26]

Treatment of Infected Sternums

The type of sternal defect determines stability and physiologic integrity. The physiologic deficit is minimal with loss of the upper sternal body and associated ribs, is moderate with loss of the entire sternal body and associated ribs, and is severe with loss of the manubrium and upper sternal body and associated ribs. In 1957, Julian was the first to describe the median sternectomy for access to the vital midline structures of the chest. Infection rates were as high as 5%; mortality was as high as 70%.

A delay in diagnosis of sternal wound infection poses a threat to underlying anastomoses, valves, and grafts. Early recognition of an infected sternum is critical. This may be accomplished with CT scan, as illustrated below, or exploration. If the diagnosis is delayed, often large sections of bone and cartilage are lost.

CT scan showing large right-sided empyema. CT scan showing large right-sided empyema.

Historically, treatment of sternal wound infections involved debridement and the wound was left open to granulate. This method of treatment had a high incidence of morbidity and mortality and increased hospital stay. Mortality was reduced to 20% when a closed irrigation system followed by debridement and closure was devised.

Debreceni et al have used vacuum-assisted closure systems for the treatment of sternal wounds.[27] This method has been shown to facilitate early cleanup of infected sternotomy wounds and to decrease the recurrence rate significantly. This method helps prepare the wound bed for flap closure.

Additionally, Agarwal et al have also used vacuum-assisted closure therapy on sternal wounds and have demonstrated decreased wound edema, decreased time to definitive closure, and reduced wound bacterial colony counts.[28] They have implemented this therapy as the first-line management of these types of wounds. See the images below.

Infected and open sternal wound after coronary art Infected and open sternal wound after coronary artery bypass graft.
Sternal wound debridement with vacuum-assisted clo Sternal wound debridement with vacuum-assisted closure therapy.

In 1976, Lee introduced transfer of the omentum to the mediastinum as a vascularized flap,[29] while Jurkiewicz devised muscle flap closure of sternal wounds.[30] These innovations have been paramount in chest wall reconstruction secondary to infected sternal wounds.

Muscle flaps used for sternal defects are the pectoralis turnover flap, rotation-advancement pectoralis flap, segmental pectoralis flap, RAM flap, EOM flap, LDM flap, and the omentum. The omentum usually is reserved for large sternal wounds and/or the prior sacrifice of bilateral internal mammary arteries (IMAs) secondary to debridement or harvest. See the images below.

Omental flap for obliteration of the empyema cavit Omental flap for obliteration of the empyema cavity.
Sternal wound with omental flap. Sternal wound with omental flap.
Healed sternal wound appearance after omental flap Healed sternal wound appearance after omental flap and split-thickness skin graft.

The most common flap uses the pectoralis muscle. The split pectoralis turnover flap entails transecting the muscle from the lateral attachments, dissecting the flap off the anterior chest wall, and turning the muscle over its medial attachment to fit into the sternal defect. The blood supply relies on the IMA and intercostal perforators.

The rotation-advancement pectoralis flap is elevated from medial to lateral, sacrificing the medial blood supply and relying on the thoracoacromial pedicle. The flap is detached from the humerus and advanced medially and rotated superiorly. This flap is ideal for upper sternal defects. When possible, Nahai et al recommend harvesting the superior part of the PMM for turnover in the management of sternal wounds and keeping the inferior part of this muscle intact, thus resulting in much less chest wall deformity.

The segmental pectoralis flap is used if the IMA has been eliminated. This flap is a combination of the split pectoralis turnover flap for the lower half of the muscle and the rotation-advancement pectoralis flap for the upper half of the muscle. The lower half relies on its intercostal blood supply. The rectus abdominis can be harvested and rotated about its superior epigastric pedicle and placed in the sternal defect.

The contralateral side also may be used if the IMA is taken; however, this flap may be used ipsilaterally in light of IMA absence due to intercostal perforators. Other flaps, which are not as popular for sternal wounds, are those using the EOM and the LDM. These are used mainly for chest wall reconstruction or when the flaps mentioned above are unavailable.

Soft Tissue Reconstruction of the Chest Wall

Partial-thickness defects most commonly are treated with skin grafting, preferably split-thickness grafting for larger surface areas. These grafts tend to heal well and provide adequate coverage. However, their limitation necessitates a well-vascularized bed. Full-thickness muscle flaps are chosen based on the skin requirements of the defect, stability of the thoracic wall, the need to protect the thoracic viscera, and donor site considerations. The most common muscle flaps used are the LDM, PMM, and RAM.

Latissimus dorsi muscle

This is a versatile and reliable muscle for chest wall reconstruction. It has a sturdy vascular pedicle and can be elevated and rotated through a generous arc to reach the entire ipsilateral chest as well as the mid line and contralateral axillary fold. This flap is durable and its neurovascular pedicle has been demonstrated to remain intact even after irradiation or ipsilateral axillary lymph node dissection.[31, 32]

McCraw has detailed the transfer technique of this flap.[33] Distal skin islands taken from regions overlying the lumbodorsal fascia have been described by Matsuo to reach the contralateral axillary regions with minimal incidence of flap loss.[34] When no vascular pedicle to the LDM can be demonstrated, May also has proven a double musculocutaneous unit comprising the LDM and underlying teres major and its vascular collateral to be successful.[35]

The serratus artery branch to the LDM also has been proven to be an adequate vascular supply to the LDM when ligation of the thoracodorsal artery has occurred. When the LDM is used, minimal functional impairment is appreciated. Only forceful backward extension and adduction of the arm are noted as mildly-to-moderately compromised.

Pectoralis major muscle

This muscle flap also has been proven to be versatile in anterior chest wall reconstruction, mainly by Arnold and Pairolero.[36] This muscle can be detached from its origin and insertion, leaving its neurovascular pedicle as its only attachment; the muscle then can be rotated into the defect. Small skin islands also can be harvested with the muscle, leaving donor sites for primary or split-thickness skin graft closure. Harvesting the pectoralis from the nondominant chest is preferable, if possible, to minimize functional impairment.

Rectus abdominis muscle

This muscle flap has been an issue of controversy. It poses a greater risk than the LDM or PMM. The morbidity associated with this flap includes abdominal wall herniation, especially below the arcuate line. Nevertheless, Moon and Taylor describe the techniques associated with RAM transfer and delineate a few important principles.[37]

These include evaluation of the skin paddle harvested with the muscle (vertical and upper transverse flaps have the best blood supply), communication of the deep inferior and superior epigastric arteries in the paraumbilical region by means of choke vessels, inclusion of a strip of anterior rectus fascia, and risks of splitting the muscle.[38] When raising a musculocutaneous flap, the skin paddle should incorporate the paraumbilical region for optimal blood supply and survival of the skin paddle.

The transverse rectus abdominis myocutaneous flap (TRAM), when based superiorly, has an arc of rotation that reaches bilateral nipples. The question remains: After bilateral IMA harvest, can the rectus still be used? Fernando and Nahai et al have successfully described the use of the rectus in this scenario specifically and have confirmed the importance of collateral circulation from the intercostal vessels near the rib margin.[39] Furthermore, the costomarginal artery is a critical blood supply to the rectus, especially when the epigastric system is compromised.

Omentum

Fix et al place emphasis on the omentum flap for chest wall reconstruction, especially for most radiation injuries. Its use may be for protection of visceral injuries or anastomoses as well as protection of vascular conduits. The omentum is a dependable and versatile flap that allows coverage of virtually all chest wall defects and is associated with low morbidity and minimal deformity. Its pitfall primarily focuses on performing a celiotomy, yet the harvest of the omentum is routinely done laparoscopically.

The left and right gastroepiploic vessels and the collateral circulation via the gastroepiploic arch and Barkow marginal artery are important vessels to recognize. The omental attachments to the transverse colon and greater curvature need to be taken down, rendering a bipedicle flap (both sets of gastroepiploic vessels). A single pedicle flap increases the arc of transposition and more so reliance on Barkow marginal artery solely for flap viability.

Ghazi et al have shown that the omental flap, though reliable and well indicated, appears to be a marker for increased mortality.[40] This association exists especially in salvage procedures and is related to the complexity of the clinical situation rather than the type of flap.

Other flaps

The external oblique muscle may be used, yet is reserved for defects below the fourth costal interspace due to its limited superior rotation. The serratus anterior muscle also has been described for small defects in the chest wall and for bronchopleural fistulas. The triceps brachii, namely the long head, has been a muscle used especially in conjunction with partial TRAM failure. The skin island overlying the triceps is usually adequate. Subjectively, the functional impairment is minimal.

Fasciocutaneous flaps

The advantages of fasciocutaneous flaps include (1) no need exists for repositioning the patient, (2) the abdominal donor site can be closed primarily, and (3) a low incidence exists of abdominal wall herniation since the rectus muscle remains intact. Harvesting the anterior rectus fascia provides better vascularity to the skin. Flaps with a base-to-length ratio greater than 1:3 have been reported to survive.

Teich-Alasia demonstrated flaps more than 40 cm long spanning subscapula to pubis when closure of donor sites involved extensive abdominal wall undermining.[41] When harvesting these fasciocutaneous flaps, perforators from the superficial epigastric system must be preserved proximally to ensure viability of the flap.

Osteocutaneous flaps

The intercostal flap with an underlying rib based on its neurovascular pedicle may be used to close small defects and retain sensory properties. Cases have been reported in which osteomusculocutaneous flaps such as the LDM, 11th and 12th ribs, and the posterior parietal pleura have been used with success.

Free flaps

The indications to use free flaps in the face of several local and/or regional flaps are unavailability of the local flap (used, divided), the large surface area of the defect, or its distant reach. Free flaps used by Hidalgo have been primarily the RAM and the LDM.[42]

In addition to free muscle flaps, free perforator flaps have also been used to reconstruct large chest wall defects. Sullivan et al have found the free deep inferior epigastric perforator (DIEP) flap to be durable and reliable with minimal donor site morbidity.[43]

Autogenous and Alloplastic Material - Reconstructive Technique of the Skeletal Structure

As stated by Pairolero and Arnold, on reviewing 205 patients with chest wall defects, reconstruction of the defect depends on the presence of infection, radiation injury, size of the defect, and location.[11] The size threshold for which a defect needs to be repaired remains unclear. The current suggestion is to reconstruct defects that produce a physiologic flail and/or a compromise in breathing mechanics. This threshold is often a defect larger than 5 cm in diameter. Defects smaller than 5 cm may be closed using soft tissue alone and rigid replacement is not necessary.

Several choices of materials are available, each with advantages and disadvantages. Consideration of which material to use involves availability of the prosthesis, ease of use, durability, adaptability, nonreactivity, resistance to infection, and translucency to x-rays. If the defect is clean, prosthetic material is indicated for the repair of skeletal defects. The list includes alloplastic material such as stainless steel, titanium, Lucite, and fiberglass; synthetic materials include Prolene mesh, Vicryl mesh, Gore-Tex, polypropylene, nylon, silicone, Teflon, acrylic, and silastic.[44] Composite synthetic materials comprise Marlex mesh and methyl methacrylate.

The use of ribs as bone grafts has proven success and durability. Grafts should be placed so that they overlap as much surrounding trabecular bone as possible to prevent resorption and fibrous capsular replacement. New osteocytes replace the bone graft with new bone. Remembering to widely débride necrotic tissue and cartilage is critical. Ribs can be harvested whole or split longitudinally. The latter option poses no defects at the donor site.

The disadvantages of using ribs are pain and/or instability at the donor site. Other sites for bone harvest are the iliac crest, fibula, and tibia. Phased-out options for skeletal patching are the fascia lata (prone to infection, predictable instability secondary to inherent flaccidity, and pain at the donor site), fascia lata with bone chips (minimal stability attained with complete bone absorption), Lyodura (dura mater), and ox fascia (becomes flaccid with time and cannot be molded).

Marlex often is used. Sutured tightly, it provides semirigid support that usually can be removed, leaving the fibrous capsule as an adequate and reliable chest wall layer. Since Marlex mesh has a tendency to fragment, combining it with methyl methacrylate solves this problem. McCormack reviewed methyl methacrylate composite.[17] The alloplast is allowed to remain in the chest for 6-8 weeks. This is enough time to allow a fibrous capsule to form. The composite is removed at this time. Infection is the most common complication. Seromas that develop around the Marlex mesh are better left untapped to prevent seeding and infection. Antibiotics must be started if an infection ensues, which may require prosthesis removal.

Although the use of Marlex for skeletal stabilization has been demonstrated to decrease respirator time and hospital stay, the incidence of infection was higher in the group that received Marlex versus the group that did not. Gore-Tex often is preferred to Marlex because of its malleability, flexibility, durability, conformability, and impermeability. In the event of infection, the patch often can be removed, and a fibrous capsule remains as adequate support. Absorbable polydioxanone (PDS) prosthesis also has been used with excellent results.

Poland Syndrome

Treatment of Poland syndrome is primarily for aesthetic reasons since the functional impairment is minimal. Assess the ipsilateral LDM because it most likely is the donor muscle for transpositional repair. Also, exclude Möbius syndrome by inspecting cranial nerves VI and VII.

The mainstay of Poland syndrome chest wall reconstruction involves harvesting the ipsilateral LDM, detaching it from the lumbodorsal region, and reflecting the muscle about its thoracodorsal pedicle to cover the anterior superior chest wall. In females, since development of the silicone shell saline-filled breast prosthesis, the ability to create a near-normal breast depends on a few factors. Many advocate skeletal reconstruction prior to muscle transposition and soft tissue contouring. This topic is controversial and some studies suggest that mild-to-moderate deformities can be managed satisfactorily by latissimus dorsi transposition alone.

If an implant is incorporated into the LDM transposition without prior stabilization of the skeletal structure, a high incidence exists of prosthetic dislodgment and unsatisfactory breast projection and symmetry. The initial step should be reinforcement of the anterior chest wall with a synthetic overlay of Marlex or Prolene mesh prior to muscle flap transposition.

At a second operation, the flap and implant are constructed. Most rib cages in patients with Poland syndrome are normal but in those with extreme skeletal deformities, the sternum is rotated considerably toward the deformed side, and the contralateral anterior chest involves a carinate deformity. This correction entails a contralateral subperichondrial split-rib cartilage resection and grafting and sternal osteotomy to allow anterior displacement and orthorotation of the sternum.

Two schools of thought exist regarding timing of the operation. Anderl and Kerschbaumer are among the authors that advocate early repair of Poland syndrome.[45] They theorize that muscle transposition at a young age facilitates a patient's learning to use the muscle in its new position and stimulates adjacent skeletal and soft-tissue structures to develop and function normally. Psychological reasons also favor early repair to avoid social and personal image conflicts.

In the ideal situation, surgery in young adolescent girls should be postponed until full breast maturity at aged 18 or 19 years, thus minimizing postoperative breast asymmetry. One solution to early operation that maintains breast symmetry, suggested by Argenta et al and Versaci et al, involves using a tissue expander inserted during early childhood that is gradually expanded as the child progresses through puberty.[46, 47] Finally, the expander is replaced by an implant and LDM transposition. Capsular contracture remains the leading cause of asymmetry in these patients.

Pectus Excavatum

Silicone implants are best used in patients who are beyond their growth spurt and are asymptomatic. This aesthetic elective procedure falls under the category "camouflaging procedures" first described by Murray.[48] Reconstructive procedures involve infants with severe compromising cardiopulmonary abnormalities. When the transverse chest to narrowest anteroposterior diameter exceeds 3.25:1, this is believed to indicate surgical repair.

According to Haller et al, reconstruction is encouraged prior to the completion of puberty, ideally when the patient is aged 4-6 years, to "relieve structural compression of the chest and allow normal growth of the thorax, to prevent pulmonary and cardiac dysfunction in teenagers and adults, and to obviate the cosmetic impact that may cause a child to avoid sports and gymnastics."[49]

The various techniques involved in repairing pectus excavatum range from internal braces to external braces, metal struts to absorbable struts, and minimal dissection to complete resection. Ravitch describes his technique, which demonstrates resecting the involved costal cartilages, performing a transverse osteotomy of the anterior and posterior table of the sternum, and implanting a wedge bone graft to correct the angulation.[50]

Haller has modified this technique to create a "tripod fixation" involving removal of 3-4 overgrown costal cartilages, anterior repositioning of the sternum after osteotomy, and placement of a posterior internal sternal support created by the child's lowest normal ribs.[49] A temporary bar is inserted below the sternum to facilitate anterior sternal displacement. This final step was modified by Hayashi et al to include a vascularized rib graft to replace the temporary metal bar.[51]

Poly-L-lactide (PLLA) was instituted by Matsui and has demonstrated good results when used as an absorbable strut to aid in anterior displacement of the sternal plate.[52] PLLA retains 90% of its mechanical strength for more than 3 months after implantation. Controversy over the procedure described by Wada,[53] involving complete resection of the sternum including transection of bilateral IMAs and complete turnover of the entire complex, led Doty and Hawkins and Ishikawa to preserve one or both mammary arteries during this maneuver.[54, 55]

The sacrifice of the arteries increases the potential for avascular necrosis and secondary infection of the sternum. Similar to the implanted metal strut described previously, Wolf devised an external modified Jewett brace that would support the sternum after cartilage resection and sternal osteotomy by transcutaneous wires.[56]

The advantages to this technique are comparable results, no need for a second major operation to remove the supportive strut, and reduced operative time. The major disadvantage is the cumbersome brace that is worn for 6 weeks postoperatively.

A study by Udholm et al found that pectus excavatum correction did not lead to improvement of cardiopulmonary function in adults. Neither cardiac output nor maximum oxygen uptake were significantly changed in the study’s 15 patients at 1-year follow-up.[57]

Complications

The primary complication encountered with chest wall reconstruction is associated with infection, whether from initial wound contamination and inadequate debridement or secondary infection. Poor planning when harvesting the pedicle flap and careless sacrificing of essential arterial perforators may result in muscle flap necrosis and skin paddle epidermolysis. Closed system drains also are essential for both donor and recipient sites. Infection is controlled with wide debridement and irrigation and coverage with well-perfused viable tissue. Consequently, the incidence of infection associated with allografts and artificial material is higher. Osteomyelitis is also a difficult infection to treat and often requires debridement that may render the defect worse than the initial presentation.

Removal of skeletal elements may cause an alteration in pulmonary physiology, thus resulting in respiratory compromise. Extrusion of allografts, primarily the struts and bars made of surgical steels, often is observed with time, especially when the ends of the support are placed beneath a pressure point. Perform shortening, pedicle flap padding, or removal of the prosthesis in these instances.

Muscle flap harvest rarely leaves the patient with debilitating functional impairment, yet extensive resection, usually with multiple operations, results in poor cosmetic outcome. Keloid scars and contractures also are observed in a small group of patients, but these minor complications are usually subtle compared to the causative insult. Harvest of the serratus anterior muscle for procedures such as thoracoplasty may result in scapular flare. Harvesting muscles closely associated to the thoracic cage presents a slight risk of pneumothorax. Inadequate closure and reinforcement of the abdominal wall fascia after harvest of the RAM has been demonstrated to increase the incidence of abdominal wall hernias.

A study by Kozlow et al indicated that an increased visceral fat area and other abdominal factors lead to a greater risk of complications from sternal reconstruction with vascularized flaps. Using computed tomography (CT) scans of the abdomen from 34 patients who underwent sternal reconstruction, the investigators found that the incidence of complications was increased in patients with relatively greater visceral and subcutaneous fat areas, as well as a greater total body area and circumference and an increased fascia area and circumference.[58]

Outcome and Prognosis

Chest wall defects frequently are encountered in all regions of the chest. Reconstruction may be required after resection of malignant tumors, radiation injuries, trauma, or infection. The ideal reconstruction should provide enough stability in the chest wall to allow adequate and spontaneous ventilation, protect intrathoracic organs, and be aesthetically appropriate. Chest wall resection and reconstruction continue to provide a formidable challenge; however, recent surgical techniques have provided ways to repair defects of almost any size with minimal functional impairment. The initial assessment in chest wall reconstruction includes evaluation of the location, extent, and etiology of the defect.

Options for soft tissue reconstruction include pedicle flap transposition and microvascular free flap transfer. Defects limited to partial thickness readily are covered with split-thickness grafts provided the recipient bed is vascular. Local muscle or musculocutaneous flaps are reserved for full-thickness transthoracic wall defects, often related to extensive debridement from osteomyelitis or osteoradionecrosis. Extensive full-thickness defects requiring skeletal support often are treated with whole or split grafts, which are preferred for elective sterile defects. Allografts such as Marlex, Gore-Tex, and Prolene mesh can provide stability and support for complex defects. Free flap tissue transfer usually is left as a last option when local or musculocutaneous flaps are unavailable.

With a given chest wall defect, the surgeon must properly devise a plan that balances function, durability, and aesthetics in the reconstructive effort.

Future and Controversies

Today, infected wound beds of the chest are debrided, and vacuum-assisted closure is used. This has decreased wound size, edema, and bacterial counts, which facilitates wound closure with various flaps.

AlloDerm (devascularized cadaveric dermis) has been used in chest wall reconstruction in an infected field with success. Prosthetic mesh cannot be used in this setting.

In addition to using muscle flaps, plastic surgeons are using fasciocutaneous and perforator flaps in the reconstruction of the chest wall.[59] The deep inferior epigastric perforator (DIEP) flap, the anterolateral thigh flap, and the superior gluteal artery flap have been used in recent years.

A literature review by Florczak et al indicated that perforator pedicled propeller flaps (PPPFs) are an effective tool for chest reconstruction. The study, in which most patients required chest reconstruction due to oncologic surgery (34.5%) or infection (11.5%), reported that complications were found in 9.9% of patients, with wound dehiscence and hematoma/seroma occurring at the highest rates (4.4% and 2.2%, respectively). The investigators stated that donor site morbidity for PPPF was lower than that for muscle flaps. Subfascial dissection was used in 78.5% of cases.[60]

Advances in research and microvascular techniques will continuously add to the armamentarium of the plastic surgeon in the reconstruction of the chest.