136: Sternal and Clavicular Chest Wall Resection and Reconstruction

Sternal resection is primarily required for primary or secondary malignancy, infection, or radiation osteonecrosis (radiation osteitis).^1,2 The resulting chest wall defect involving loss of skeleton and often overlying soft tissue depends on tumor extent and type, and severity of infection or radiation necrosis. Full-thickness sternal resections can compromise chest wall stability or have paradoxical respiratory movements, highlighting the importance of proper reconstruction of the thoracic wall and sternum.

Primary tumors of the thoracic skeleton are rare, accounting for 4.5% to 8% of published series of primary bone tumors with 11% in the sternum and 9% in the clavicles.³ Sternal tumors are classified as primary tumors (i.e., benign or malignant), adjacent tumors with local invasion (i.e., lymphoma or primary neoplasm of lung, breast, pleura, or mediastinum), metastases (i.e., primary neoplasm of breast, lung, or thyroid), and nonneoplastic lesions (i.e., inflammatory masses or bone cysts). The majority of sternal tumors are malignant and frequently represent metastasis or direct invasion by adjacent tumor.^1,4,5 The majority of primary sternal malignancies are bony or cartilaginous in origin.^3–5 The most common primary malignancy of the sternum is chondrosarcoma, and other common primary malignancies include osteosarcoma, solitary plasmacytoma, and Ewing sarcoma.^3–5 Although primary benign tumors of the sternum are rare, the most common benign tumors of the sternum are chondroma and osteochondroma.⁶

Most clavicle tumors are malignant and much more likely to be metastases than primary tumors. Primary neoplasms of the clavicle are rare. The most common primary malignancy of the clavicle is solitary plasmacytoma.⁷ Isolated clavicular resection is rare. Indications for resection include (1) exposure of the base of the neck, superior mediastinum, or brachial plexus, (2) tumor, infection, or injury/trauma of the clavicle itself or in association with sternal/chest wall resection, and (3) dysfunction of the sternoclavicular and acromioclavicular joints.⁸ Distal clavicle pathology generally entails dysfunction of the acromioclavicular joint which is usually managed by orthopedic surgeons specializing in shoulder reconstruction. The distal end of the clavicle is commonly resected for arthritis and dislocation of the acromioclavicular joint. Partial, medial clavicular resection is required during an anterior approach to superior sulcus tumor resection (Chapter 80).⁹ In addition, clavicular resection may be sufficient to provide exposure of the ipsilateral superior mediastinum during head and neck operations obviating the need for a partial or complete median sternotomy.

Careful preoperative evaluation, including assessment of cardiopulmonary reserve, is critical for successful outcome. A detailed history should identify comorbid factors such as advanced age, malnutrition, overall debilitation, and cardiopulmonary disease. Severe respiratory insufficiency is considered a contraindication for extensive sternal resection. There should be a clear understanding of the patient's prior operations with attention to location of previous incisions and radiation treatment history, including location and dosage of exposure. This information is critical in establishing the reconstructive plan, particularly when assessing availability and usability of muscle and omental flaps.

An extent of disease workup to determine appropriateness of resection should be thoroughly investigated. Given the high propensity for metastases to occur in the sternum and clavicle, there should be investigation for a primary tumor elsewhere. Our preference is a whole body PET/CT scan with intravenous contrast to assess for extrathoracic disease. CT scan of the chest with intravenous contrast is the single best radiographic modality to localize and characterize the sternum, clavicle, and chest wall. Thorough knowledge of the extent of involvement by sternal or clavicular pathology (e.g., mediastinal structures, pulmonary parenchyma, ribs, sternum, clavicles, and overlying soft tissues) is readily obtained through CT scanning. Although MRI of the chest is not mandatory in every case, it can be quite helpful in evaluating invasion of the thoracic inlet, brachial plexus, and subclavian vasculature. MRI is also useful in characterizing cartilage and soft tissue, and is more sensitive in evaluating bone marrow edema and replacement than CT. Image guided (CT or ultrasound) core needle biopsy of chest wall and sternal tumors has been shown to be a safe and highly accurate diagnostic modality to determine malignancy, histological subtype, and high-grade differentiation of musculoskeletal tumors.¹⁰ Preoperative tissue diagnosis should be obtained to determine presence and type of malignancy and also to consider neoadjuvant or definitive chemotherapy depending on the tissue diagnosis.¹⁰ On this basis, imaged guided needle biopsy is routinely performed before resection, and incisional biopsy is rarely needed.¹⁰

Given the rarity of sternal and clavicular mesenchymal tumors, a multidisciplinary team approach to guide management and treatment plans is recommended.¹⁰ Preoperative treatment may be appropriate in some situations (i.e., metastases, high-grade soft tissue sarcoma, osteosarcoma, Ewing sarcoma, and mesenchymal or dedifferentiated chondrosarcoma). Consultation with a plastic surgeon to devise plans for soft tissue reconstruction may be necessary for complex situations, such as those requiring extensive myocutaneous flaps (Chapter 138).

General Principles

The sternum provides structural support for the thoracic skeletal structures and stabilizes the shoulder girdle through the clavicles. In addition, it provides a protective barrier to the mediastinum, particularly the great vessels and the heart. Surgical principles governing resection of the sternum or clavicle emphasize the importance of a complete resection with clear margins. Repair or reconstruction of these bony defects requires the selection of appropriate prosthetic and/or autologous replacement material. It is important to stabilize the chest wall and sternum to maintain the normal dynamics of respiration and to protect mediastinal structures. Current techniques most often entail the use of rigid prostheses and soft tissue (muscle or omentum) coverage to ensure adequate healing. The use of soft tissue reconstructive techniques is imperative in any irradiated field to prevent incisional dehiscence and wound infection. Local wound complications have attendant risks for prosthetic contamination and may delay initiation of adjuvant therapy depending on the tumor type.

Anesthesia

Preoperative placement of a thoracic epidural is used routinely for postoperative pain management unless contraindications exist, such as coagulopathy, systemic infection, anticipated cardiopulmonary bypass (CPB), or immediate need for postoperative therapeutic anticoagulation. Antibiotic prophylaxis is administered prior to incision. Subcutaneous heparin and pneumatic compression stockings are used for deep vein thrombosis prophylaxis, especially since the majority of patients have an underlying malignancy. General anesthesia is induced with initial single-lumen intubation for bronchoscopic examination followed by exchange to a double-lumen endotracheal tube to facilitate resection in the supine position. Single lung isolation is useful especially if there is involvement of adjacent lung parenchyma, concomitant chest wall or rib resection, or to facilitate resection of the sternochondral junction during sternectomy.

Positioning of the Patient

Sternectomy or claviculectomy generally requires the patient to be in the supine position. The chest and abdomen should be prepped widely to provide adequate access to potential muscle or omental flaps. The thighs should be prepped if skin grafting becomes necessary. Prior to tumor resection, there should be consideration for initial harvest of the pedicled latissimus dorsi muscle flap in the full lateral decubitus position through a vertical incision along the anterior edge of the muscle to the axilla or through a standard posterolateral thoracotomy incision. Sterile prepping of the entire ipsilateral upper extremity can facilitate dissection of the latissimus dorsi muscle but is not mandatory. In this case, all intravenous or arterial catheters should be placed in the contralateral arm. The lateral decubitus position is essential for adequate exposure for optimal latissimus dorsi muscle flap harvest. The dissected muscle flap can be tucked into the axilla and later retrieved during sternal or clavicular resection in the supine position. The latissimus dorsi muscle is our preferred flap for soft tissue coverage following sternectomy or claviculectomy. If the latissimus dorsi muscle is not available or suitable, then the pectoralis major muscle (ipsilateral and/or contralateral), transverse rectus abdominus myocutaneous (TRAM) flap, or omentum are alternatives, and can be harvested in the supine position during or after tumor resection. The pectoralis muscle is ideally suited for upper chest wall/sternal defects. The TRAM and omental flaps can reach essentially any part of the anterior and lateral thorax and sternum. However, the use of a superiorly based pedicled TRAM flap is limited given the need for preservation of ipsilateral internal mammary artery, which is generally resected in total sternectomy.

Supine positioning is the ideal position for sternal or clavicular resection. A transverse shoulder roll can be helpful to allow mild neck extension (Fig. 136-1A). In addition, a slight elevation or lateral decubitus position at 30- to 45-degree rotation ipsilateral to the clavicular resection or concomitant chest wall rib resection will provide a wider field for the tumor resection and ease retrieval of the latissimus dorsi muscle flap from the axilla (Fig. 136-1B). The ipsilateral arm should be tucked to the side. This positioning also facilitates the insertion of a thoracoscope when there is involved lung that requires en bloc resection or to evaluate the entry point into the chest wall lateral to the sternum to ensure that adequate margins are achieved in cases of concomitant sternal and chest wall tumor resection or when there is a significant intrathoracic/mediastinal component compared to the extrathoracic sternal part of the tumor.

Incisions

A variety of incisions can be used depending on the location of the tumor. For a sternal or manubrial tumor, a vertical midline incision is made centered over the portion of the involved manubrium or sternum (Fig. 136-2A). For a clavicular/manubrial tumor, or upper sternal tumor, a reverse hockey stick incision can be made (Fig. 136-2B). For a lower sternal tumor involving the sternochondral junctions or chest wall ribs, a partial hemiclamshell incision (Fig. 136-2C) or lower midline vertical incision can be made. In women, the hemiclamshell incision can be extended from the midline sternum to along the ipsilateral breast crease to permit utilization of the ipsilateral pectoralis muscle and breast tissue for soft tissue coverage during reconstruction. Any previous incisional biopsy scars should be excised in an elliptical manner incorporating the entire open biopsy site.

Total Sternectomy (Resection of Costal Cartilages and Sternum)

Strict adherence to aseptic technique is mandatory to avoid incisional wound and prosthetic infection. Perioperative antibiotics are administered within 1 hour before incision. Antimicrobial surgical drapes with an iodophor impregnated adhesive (3M™ Ioban™ 2 Antimicrobial Incise Drape, 3M, St. Paul, MN) is used to maintain adherence of the drape to the patient and prevent contamination of the operative field. This also prevents contact of prosthetic materials to the patient's skin and flora.

A midline sternotomy incision is made from the sternal notch to the xyphoid. If the tumor extends close or invades the skin, then the overlying skin is resected en bloc with the sternal tumor. Subcutaneous flaps are created circumferentially by dissecting down onto the fascia of the pectoralis major muscles bilaterally. If the tumor invades the pectoralis major muscle, then en bloc resection of the muscle with the tumor is performed with a wide soft tissue margin of at least 4 cm for high-grade, primary sternal malignancies. Otherwise, the pectoralis major muscles are elevated as flaps off the sternum and costal cartilages bilaterally. Dissection is extended to expose the costal cartilages and the sternochondral junctions. Blunt dissection on the inner table of sternum at the sternal notch and at the xyphoid level is performed to release strap muscle attachments and the diaphragm attachments from the inner table of the sternum, respectively. The costal cartilages are divided from a caudal to cranial direction allowing for at least a 4-cm margin (Fig. 136-3A,B). The bilateral pleural cavities are entered. The inferior epigastric arteries are ligated bilaterally. The intercostal neurovascular bundles are ligated and divided. The lower part of the sternum is lifted anteriorly allowing visualization of the sternal undersurface. The anterior mediastinal/pericardial fat, thymus, or pericardium can be resected en bloc if tumor invasion is present. The internal mammary arteries are identified, ligated, and divided bilaterally in the upper sternal area. When the entire sternum is involved by tumor or total sternectomy is required to achieve margin negativity, the sternum is resected in its entirety with the manubrium with or without resecting the clavicular heads. When the manubrium must be resected in its entirety, the sternoclavicular joint can be disarticulated with preservation of the medial clavicular heads bilaterally. In general, the extent of margin clearance is determined primarily by tumor type and grade. For benign and metastatic lesions, negative margins are adequate. For low- and high-grade primary sternal sarcomas, 2- and 4-cm margins are required, respectively. For associated sternal and chest wall tumor resections, one rib above and below the tumor are resected to achieve adequate margins.

Partial Sternectomy

A partial resection of the sternum with or without chest wall and ribs may be sufficient for smaller tumors and is accomplished either by division of the ribs or cartilages bilaterally for centrally located tumors or by division of the ribs or cartilages on the ipsilateral side of an eccentrically located sternal tumor (Fig. 136-4A,B). The tumor is resected with the same principles as described for a complete sternectomy. If complete resectability is not compromised, preservation of at least part of the manubrium or lower part of the sternum can provide chest wall stability and facilitate an easier reconstruction.

Reconstruction Options

Reconstruction after sternal resection is necessary to provide chest wall stability for support of respiration and to protect the underlying organs (e.g., heart and great vessels). Reconstruction is performed at the time of sternal resection unless there is associated infected tissue requiring dressing changes and systemic antibiotics before definitive reconstruction with autologous grafts. Sternal reconstructions entail autologous soft tissue transpositions and prosthetic substitutes.^2,5 Autologous tissue transpositions include omentum and muscle flaps that can be harvested with or without overlying skin (Chapter 138). Prosthetic substitutes include polytetrafluoroethylene (PTFE), methyl methacrylate (MMC), and polypropylene mesh.^2,5

Preferential use of autologous tissue rather than prosthetic substitutes in sternal reconstruction is not clearly established except in cases of infection. Exclusive use of prosthetic materials in cases of active or deep tissue infection is contraindicated for final reconstruction but is appropriate occasionally for interim stabilization during dressing changes. In many instances, definitive reconstruction requires the combined use of prosthetic material and autologous tissue flaps.

PTFE is flexible and durable, and easily conforms to the contour of the chest wall. Although not an essential characteristic, it is impermeable to fluids and gases. It is available in a variety of thicknesses. Gore DualMesh (2-mm thickness) is used most often for chest wall reconstructions and in combined chest wall and partial sternal reconstructions. The radiolucency of this prosthesis permits easier radiographic surveillance for cancer recurrence.

Prolene or Marlex mesh, a double-stitch knit mesh with relative rigidity, is a commonly used polypropylene mesh. It is semipermeable, permitting fibroblast in growth, which is responsible for tenacious incorporation into the surrounding soft tissues.

MMC is a flammable liquid. When activated by an appropriate resin, it develops into a semisolid prosthetic substance that remains malleable for only a brief period (approximately 2 minutes) before it hardens. Since the exothermic reaction can reach temperatures of 50°C, causing necrosis of surrounding tissue, it should be molded to the appropriate contour and allowed to harden without making direct contact with the patient's tissues. Studies have proved that the rigidity and limitation of chest wall movement caused by this prosthetic material do not impair postoperative pulmonary function. MMC is radiolucent. It is commonly used in combination with polypropylene mesh in a sandwich technique discussed in detail below.

Reconstruction for sternal tumors begins with an assessment of size and location of the defect. These factors guide the choice for sternal prosthetic substitutes or autologous tissue transpositions.

Reconstruction for Total Sternectomy

Complete sternectomy requires reconstruction with rigid prosthesis to provide sturdy support to the chest wall and protection of the mediastinum and soft tissue coverage of the prosthesis. The polypropylene/MMC sandwich technique is employed. A Prolene mesh (30 cm × 30 cm) is folded over itself creating a double-layered polypropylene mesh (Fig. 136-5A). The viscera retainer should be placed over the anterior mediastinum to protect the heart and great vessels from the exothermic reaction of the MMC hardening process (Fig. 136-5B). There should be at least a 2- to 3-cm redundant overlap of polypropylene mesh from the resected sternal edge circumferentially (Fig. 136-5B). Interrupted #1 Prolene sutures are placed through each transected costal cartilage or resected rib and the clavicles to anchor the polypropylene mesh to the resected sternal edges. Use of a power drill through the ribs or clavicle may be necessary to allow suture placement through bone. The Prolene sutures are tied down in three of the four sides of the sternal defect (except for the left or right parasternal area) (Fig. 136-5C). The mesh should be tight to allow a rigid prosthetic reconstruction to prevent flail chest and respiratory complications. The clavicles should be sutured to the prosthesis to provide stability to the chest wall and improve shoulder function. Refinements to the prosthesis size and shape are carried out during the anchoring process so that it is sculpted and anchored to bony structures, producing a taut cover over the defect. The MMC cement is administered between the two layers of polypropylene mesh to create at least a 5- to 10-mm thick MMC layer (Fig. 136-5C). As the MMC hardens, it is molded into the shape of the patient's native sternum. The sternal notch should be contoured and created from the hardening MMC. Angiocatheters (14 or 16 gauge) are placed through and through the double-layered polypropylene mesh and MMC sandwich creating holes in the prosthesis to facilitate drainage of any postoperative seroma over the prosthesis into the mediastinum, alleviating the need to place any drains directly over the prosthesis (Fig. 136-5D). The viscera retainer provides protection of the heart during angiocatheter placement and heat created from the MMC. The needles are removed from the angiocatheters while the MMC is hardening. Upon completion of the exothermic reaction from the MMC, the angiocatheters and the viscera retainer are removed, and the remaining untied interrupted Prolene sutures are tied down (Fig. 136-5E).

The choice of autologous tissue for sternal reconstruction depends not only on the resulting sternal defect, but also on the patient's previous operations and incisions. The viability of muscle and omental transposition, advancement, and island flaps depends on a specific blood supply, which may have been disrupted during past surgical procedures or damaged from radiation exposure (Chapter 138).

The muscle or omental flap is then placed over the sandwiched prosthesis to provide soft tissue coverage. In Figure 136-5F, the use of the right latissimus dorsi muscle is depicted after being brought out from the right axilla, placed over the sternal prosthesis, and sutured to the mobilized bilateral pectoralis major muscles and rectus abdominis muscles inferiorly (Fig. 136-5F,G). Blake (19F) drains (Ethicon, Somerville, NJ) are placed over the muscle layer in the sternal reconstruction site to prevent seroma development. Drains are not placed directly over the prosthesis given the presence of holes within the prosthesis created by the angiocatheters. Drains should also be placed in the muscle harvest sites. The overlying skin is closed over the muscle flap (Fig. 136-5G). Bilateral chest tubes (28F) should be placed for pleural drainage.

Reconstruction for Partial Sternectomy

If resection has been limited to a partial sternectomy, then a rigid prosthesis may not be required depending on the location. The advantage of a partial sternectomy is that it provides the chest wall with stability due to the intact remaining thoracic skeleton. Although resection of the manubrium alone does not require reconstruction, placement of a prosthetic mesh may assist in improving the cosmetic outcome. Our preference in this instance is placement of a PTFE patch and local advancement of the bilateral pectoralis major muscles or use of the latissimus dorsi muscle for soft tissue reinforcement. The PTFE patch is fenestrated to allow seroma drainage into the pleural cavity and mediastinum. If the partial sternectomy involves the sternomanubrial junction with partial resections of the first and second ribs, then prosthetic reconstruction with the polypropylene/MMC sandwich technique is recommended to provide chest wall stability. If less than one third of the lower sternum is resected, then reconstruction is not necessary. However, our preference is placement of a PTFE patch to improve cosmetic outcome. Larger resections of the sternum will expose the heart necessitating reconstruction with the prosthetic sandwich technique. Combined partial sternal and right parasternal chest wall resections can be reconstructed usually with PTFE patch placement. However, combined partial sternal and left parasternal chest wall resections usually require reconstruction with a rigid prosthesis to provide protection of the heart mandating the prosthetic sandwich technique.

Postoperative Care and Complications

The most common complications of sternal resection and reconstruction are seroma formation, wound infection, flap necrosis, reconstruction dehiscence, and respiratory complications (i.e., pneumonia and respiratory failure).^2,5 Seroma development can occur over prosthetic materials, especially after reconstruction with PTFE. The key to seroma management is prevention by fenestrating the PTFE patch or creation of holes through the prosthetic sandwich to allow seroma drainage into the mediastinum and pleural space. In general, we do not place drains directly over the PTFE patch or prosthetic sandwich reconstruction site. However, drains are placed over the muscle flap at the reconstruction and harvest sites until drainage is less than 30 mL per day for 2 consecutive days. Seromas usually resorb over weeks but may occasionally require aspiration with strict sterile technique. This can take 2 to 4 weeks from surgery before removal, particularly at the latissimus dorsi muscle harvest site. A first generation cephalosporin antibiotic is given until drain removal.

Postoperative wound infection is a significant concern given the attendant risk of prosthetic contamination. If a wound infection occurs, then aggressive local wound care and intravenous antibiotics directed against cultured organisms are warranted. Removal of the prosthetic material is generally required, particularly in the early postoperative period. If the prosthesis requires removal, a biologic material can be used for temporary reconstruction to maintain chest wall stability, such as Alloderm (Lifecell Inc., Branchburg, NJ), along with soft tissue flap coverage.

Muscle graft failure is rare.^2,5 During harvesting of the flap, preservation of the associated vascular supply is critical to preventing graft necrosis. Loss of muscle flap viability generally requires reconstruction with another flap. Omental transposition is an excellent alternative in situations of muscle flap related complications. Avoidance of vasopressor utilization and optimizing the patient's hemodynamic status perioperatively are beneficial. Tension should be avoided when soft tissue flaps are anchored to neighboring tissues to prevent reconstruction dehiscence.

Respiratory complications are infrequent but contribute significantly to perioperative mortality.^2,5 The occurrence of pulmonary atelectasis and pneumonia are minimized with aggressive postoperative pain management with routine placement of preoperatively placed thoracic epidural catheters, early patient mobilization, frequent ambulation, and chest physiotherapy. Therapeutic suctioning of airway secretions with liberal use of flexible bronchoscopy is encouraged when patients have a difficult time coughing up secretions and when aspiration pneumonia is suspected.

General Principles

Resection of the medial (inner) two thirds of the clavicle will provide sufficient exposure of the axillary and subclavian vessels, brachial plexus, and superior mediastinum. Medial resection of the clavicle may also suffice for sternoclavicular joint infections/clavicle osteomyelitis, sternoclavicular joint dislocation, and medial clavicular or sternoclavicular tumors. However, complete clavicular resection may be needed in extensive tumors and severe osteomyelitis. Severely comminuted fractures, and malunion or nonunion of the clavicle may also warrant complete resection by disarticulating the sternoclavicular and acromioclavicular joints. It has been well documented that the clavicle can be partially or completely resected without resultant disability if performed with proper technique.⁸

The sternoclavicular and acromioclavicular joints of the clavicle are stabilized by the ligaments between the clavicle and the first rib (costoclavicular ligament) and the clavicle and the coracoid process (coracoclavicular ligament), respectively (Fig. 136-6A,B). The clavicle has four primary functions: (1) acts as a prop to hold the scapula away from the body during shoulder motion, (2) provides bony framework for muscle origins and insertions (Fig. 136-6A), (3) provides bony protection of the axillary and subclavian vessels and brachial plexus, and (4) transmits the supporting force of the trapezius muscle to the scapula.⁸ The sternoclavicular and acromioclavicular joints of the clavicle are stabilized by the ligaments between the clavicle and the first rib (costoclavicular ligament) and the clavicle and the coracoid process (coracoclavicular ligament), respectively (Fig. 136-6B). The costoclavicular ligament prevents lateral displacement of the clavicle by intimately binding the medial part of the clavicle to the first rib. Loss of this ligament results in malfunction and degeneration of the sternoclavicular joint.⁸ Based on this anatomic understanding, several sites of resection can be performed with consideration of preserving the shoulder girdle functions balanced by the indication for clavicular resection (Fig. 136-7); the most common resections involving the medial two-thirds of the clavicle (Fig. 136-7B), midclavicle resection with preservation of all ligaments (Fig. 136-7D), and complete clavicular resection (Fig. 136-7E).

In situations where only the medial clavicle is resected, the transection line should extend up to the coracoclavicular ligament. Resection of the costoclavicular ligament will result in anterior displacement of the remaining clavicle with protrusion onto the skin if resection is not performed sufficiently lateral to the coracoclavicular ligament (Fig. 136-7B).

With complete clavicular resection, the functions of acting as a prop to hold the scapula away from the body during shoulder motion and bony protection of the axillary and subclavian vessels and brachial plexus are lost. However, the remaining two functions can be maintained with proper surgical techniques.⁸

Complete Clavicular Resection Technique

The patient is placed in the supine position with a transverse roll between the shoulders. The shoulder ipsilateral to the operative side is gently pulled down with moderate traction. Incision is made along the clavicle from the sternoclavicular to the acromioclavicular joint (Fig. 136-8A). Skin flaps are created superiorly and inferiorly to expose the fascia of the sternocleidomastoid, pectoralis major, deltoid, and trapezius muscles and their attachments to the clavicle. These muscles are detached from the clavicle or resected en bloc with the clavicle (Fig. 136-8B). With mobilization of the sternocleidomastoid and pectoralis major muscles, the medial aspect of the clavicle is dissected and the sternoclavicular joint is disarticulated by incising the capsule, and exposing the articular disc (Fig. 136-8C,D). The disc is severed resulting in disarticulation of the sternoclavicular joint, and the costoclavicular ligament is transected separating the first rib from the medial part of the clavicle. The clavicle is elevated and the exposed subclavius muscle is dissected off the clavicle or resected en bloc with the clavicle if indicated for complete tumor resection (Fig. 136-8C). The clavicle is resected with complete removal of the bone and associated periosteum. If the subclavius muscle is resected, then cautious dissection should be performed to prevent inadvertent injury to the underlying axillary/subclavian vasculature or brachial plexus, which is covered by the omohyoid and clavipectoral fascia (Fig. 136-8D). At the lateralmost aspect, trapezius and deltoid muscles have been detached from the clavicle. The lateral aspect of the clavicle is mobilized by incising the acromioclavicular joint. The clavicle is further elevated by transecting the trapezius and conoid segments of the coracoclavicular ligament which completes the total clavicular resection (Fig. 136-8E). In order to preserve proper muscle function, the trapezius to deltoid muscles, and the sternocleidomastoid to pectoralis major muscles are sutured together, respectively (Fig. 136-8F).

There is no attempt at reconstructing the resected bony clavicle with prosthesis. However, if there has been extensive resection of the surrounding soft tissue and musculature with resultant defect, then there should be consideration for initial harvesting of the ipsilateral latissimus dorsi muscle prior to clavicle resection as described earlier, or mobilization of the ipsilateral pectoralis major muscle following resection to provide soft tissue coverage of the resection site. The use of muscle flap coverage is encouraged if there is a large soft tissue defect and routinely performed in situations of prior radiation to reduce risk of wound complications.

Sternal resection is primarily required for primary or secondary malignancy, infection, or radiation osteonecrosis. The majority of sternal tumors are malignant and frequently represent metastasis or direct invasion by adjacent tumor. The sternum provides structural support for the thoracic skeletal structures and stabilizes the shoulder girdle through the clavicles. In addition, it provides a protective barrier to the mediastinum, particularly the great vessels and the heart. Surgical principles governing resection of the sternum or clavicle emphasize the importance of a complete resection with clear margins. Repair or reconstruction of these bony defects requires the selection of appropriate prosthetic and/or autologous replacement material. It is important to stabilize the chest wall and sternum to maintain the normal dynamics of respiration and to protect mediastinal structures. Current techniques most often entail the use of rigid prostheses and soft tissue (muscle or omentum) coverage to ensure adequate healing. The use of soft tissue reconstructive techniques is imperative in any irradiated field to prevent incisional dehiscence and wound infection. Local wound complications have clear attendant risks for prosthetic contamination and may delay initiation of adjuvant therapy depending on the tumor type. Full-thickness sternal resections can be performed with no compromise in chest wall stability or respiratory movements and acceptable morbidity if proper technique in reconstruction of the thoracic wall and sternum are applied.

Most clavicle tumors are malignant and much more likely to be metastases than primary tumors. Isolated clavicular resection is rare. Indications for resection include (1) exposure of the base of the neck, superior mediastinum, or brachial plexus, (2) tumor, infection, or injury/trauma of the clavicle itself or in association with sternal/chest wall resection, and (3) dysfunction of the sternoclavicular and acromioclavicular joints. Complete understanding of the clavicular anatomy with associated ligaments and musculature are imperative in surgical planning and preservation of clavicular function.

The authors have done an excellent job highlighting that the sternum and clavicle are not merely bony structures but rather play important functional roles which must be restored as much as possible through meticulous reconstruction. The detailed anatomical considerations and step-by-step approaches to sternal and clavicular resection and reconstruction demonstrated in this chapter are valuable additions to the repertoire of all thoracic surgeons.