N.N. Priorov National Medical Research Center of Traumatology and Orthopedics, Moscow, Russia
Published Date: 20/01/2021.
*Corresponding author: Machak GN, National Medical Research Center of Traumatology and
Orthopedics, Moscow, Russia
A clinical case of surgical treatment of a 54-year-old female patient with a localized form of chondrosarcoma of the sternum is presented. During the process of preoperative planning, 3D additive technologies were used, allowing to determine the optimal volume of bone resection and reconstruction of the resulting defect of the chest wall with an individualized titanium costosternal implant. The patient underwent successful surgery with no early or long-term complications. Respiratory function after surgery was not impaired. With a follow-up period of more than four years, no signs of local recurrence or metastases were observed. The presented case demonstrates the current possibilities of reconstructive surgery of costosternal tumors using individualized 3D implants with excellent long-term clinical, functional and cosmetic results.
Keywords: chondrosarcoma, sternum, stereo-lithographic model, individualized titanium plate, surgical treatment, case report
Tumors of the sternum constitute only 0.45% - 1% of all primary bone tumors [1-4], and most of them are malignant (5, 6). The most frequently diagnosed malignant tumor of the sternum is chondrosarcoma [1,2,7], followed by osteosarcoma, myeloma, and malignant bone lymphoma . Radical resection is considered the primary treatment option for grade II-III chondrosarcomas. Chest wall tumor surgery is technically complicated due to the difficulties of extended tumor resection without compromising skeletal stability and the need for simultaneous reconstruction of the chest . Extensive thoracic wall defects require pleural cavity and/or mediastinum closure as well as the restoring of chest wall rigidity. The latter is of paramount importance, as it helps to prevent the development of cardio-respiratory disorders in the early postoperative period and reduce mortality. Many methods have been proposed to replace a chest wall defect after resection: auto- and allografts, rib complexes, various implants, made of synthetic materials and metal [1-3,9-21] At the same time, a number of authors have noted a high rate of complications, associated with sternocostal resection and reconstruction [16,21]. With the development of modern technology, it has become possible to replace large defects of the chest wall with individualized metal implants. This approach allows to effectively restore the chest wall framework and to reduce the duration of the surgery. The current article describes a successful case of surgical treatment of a patient with a chondrosarcoma of the sternum using additive technology for surgical planning and post-resection chest wall reconstruction with an individualized titanium sternocostal implant.
A 54 y.o. patient in 2012 has discovered a bulging of the sternal area during self-examination. She had not seeked medical help for more than a year. Only in 2014, after noting an increase in the dimensions of the lesion, she underwent a tumor biopsy at a thoracic surgery department of a large medical institution, after which she was diagnosed with a chondroma. Due to the need for a sternal resection and a complex reconstruction of the chest wall, the patient was referred to our institute in 2015. Upon admission, the patient complained of a tumor-like growth in the sternum. The patient’s general condition was satisfactory. Normosthenic physique, with an increased BMI was noted. No respiratory or hemodynamic disorders were noted. In the middle third of the sternal body, a painless, dense, immobile tumor mass, measuring 70 x 40 mm and protruding 35 mm above the skin surface could be palpated. Computed tomography of the chest (Figure 1A&B) revealed a focus of osteolytic destruction located in the body and upper part of the xiphoid process of the sternum, measuring 70.8 x 25.2 x 18 mm.
Figures 1A: CT images of the patient’s thoracic cavity demonstrating a focus of osteolytic destruction located in the body and upper part of the xiphoid process of the sternum, measuring 70 x 25 x 18 mm.
Figures 1B: CT images of the patient’s thoracic cavity demonstrating a focus of osteolytic destruction located in the body and upper part of the xiphoid process of the sternum, measuring 70 x 25 x 18 mm.
Figures 1C: MRI of the thorax demonstrating an extensive lesion (70 x 25 x 18 mm) with uneven, irregular contours on the right side in the area of articulation of the ribs and sternum. The lesion invades the cortical layer of the sternum and spreads into the adjacent soft tissues.
Figures 1D: MRI of the thorax demonstrating an extensive lesion (70 x 25 x 18 mm) with uneven, irregular contours on the right side in the area of articulation of the ribs and sternum. The lesion invades the cortical layer of the sternum and spreads into the adjacent soft tissues.
The cortical layer was unevenly thinned, moderately swollen, eroded along the anterior and posterior surfaces, with a soft tissue component extending beyond the bone tissue. The contours of the soft tissue component were irregular. The structure of the lesion was heterogeneous due to inclusions of higher density. In the preserved areas of the cortical layer, periosteal stratifications could be visualized. The CT findings corresponded to a cartilaginous tumor of the sternum, most likely a chondrosarcoma. Magnetic resonance imaging of the chest (Figure 1C&D) demonstrated an extensive lesion measuring up to 70 x 25 x 18 mm with uneven, irregular contours on the right side in the area of articulation of the ribs and sternum. The lesion invaded the cortical layer of the sternum and spread into the adjacent soft tissues. The MR findings corresponded to a chondrosarcoma of the sternum.
For staging purposes, a magnetic resonance diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) was performed revealing a focus of hyperintense signal in the sternum. No other lesions were detected. Upon revision of the biopsy specimens the diagnosis of chondrosarcoma was confirmed (IB, G1, according to Enneking staging system).
Figures 2A: Stereolithographic 3D model of the sterno-costal complex of the patient, planned zone of resection and individualized titanium plate; C – intraoperative photograph after plate fixation.
Figures 2B: Stereolithographic 3D model of the sterno-costal complex of the patient, planned zone of resection and individualized titanium plate; C – intraoperative photograph after plate fixation.
Figures 2C: Intraoperative photograph after plate fixation.
To better evaluate the case and to elect the optimal method of surgical treatment, a stereolithographic 3D model of the patient’s sterno-costal complex was produced using CT data in a 1:1 ratio (Figure 2A&2B). With the help of the 3D model the extent of resection was determined and an individualized titanium costosternal plate was manufactured (Figure 2C). To minimize the risk of recurrence and maximize the rigidity of plate fixation, it was planned to respect the cartilaginous ends of the ribs.
Unique traits of this custom implant include the relative simplicity of its production, solid structure, and large surface area, which make it robust and versatile in terms of freedom of fixation to the ribs. The selected implant thickness of 1,5 mm provides sufficient rigidity and strength, but, at the same time, preserves relative elasticity of the metal, allowing for some mobility of the thoracic wall. After meticulous planning, a subtotal resection of the sternum with anterior chest wall reconstruction using an individualized titanium plate was performed (Figure 2C).
Surgical details: with the patient in the supine position, under general endotracheal anesthesia in combination with high epidural anesthesia, a 15 cm incision was made along the midline of the sternum with excision of the scar from a previously performed biopsy of the sternum. The pectoral muscles were mobilized, followed by 10 mm parasternal subperichondrial resection of the II-VII costal cartilages. The sternum was intersected with an oscillating saw 1 cm proximally to the manubriosternal joint and 1 cm distally to the xiphisternal joint. The sternum was removed with a tumor in a single block. The defect of the anterior chest wall was reconstructed with an individualized titanium plate. The proximal end of the plate was inserted into the notch in the sternal manubrium and fixed to the underlying ribs with a titanium wire. The surgical site was drained and the wound closed in layers. Intraoperative blood loss amounted to 300 ml. The patient was put in a thoracic brace. In the early postoperative period, antibacterial, infusion, anticoagulant therapy, as well as multimodal analgesia (a combination of prolonged epidural anesthesia with opioid analgesics and NSAIDs) were administered. Three hours after surgery, the patient was extubated and transferred to spontaneous breathing with oxygen support. On the second day after surgery, the patient was transferred back to the ward from the intensive care unit. On the fourth day, the patient returned to sitting in bed and walking around the ward.
Figure 3A: Gross pathology – sternal section with chondrosarcoma tissue.
Figure 3B: Lobular structure with individual lobules of the tumor separated by fibrous tissue, total destruction of the cortical plate, extension of the tumor into adjacent soft tissues. H&E stain. Х 200.
Figure 3C: Nested distribution of chondroid cells of the chondrosarcoma with large hyperchromic nuclei, numerous binuclear cells and signs of chondroid matrix myxomatosis. H&E stain. Х 200
Figure 3D: Binuclear chondroid chondrosarcoma cell. H&E stain. Х 900; E - Infiltrative extension of the chondrosarcoma into adjacent bone and soft tissue. H&E stain. Х 400.
Figure 3E: Infiltrative extension of the chondrosarcoma into adjacent bone and soft tissue. H&E stain. Х 400.
Pathological investigation of the tumor gross specimen showed dense bone tissue having an irregular nodular surface attached to fatty tissue, with dimensions of 11,0 x 4,5 x 4,0 cm. Bone section showed semi-translucent, relatively dense mostly gray hyaline cartilage with lobular structure and focal points of bone density, with overall dimensions of 7.3 x 3.8 x 3.3 cm (Figure 3A). Histological analysis demonstrated a cartilage-forming tumor of lobular structure with individual lobules of the tumor separated by fibrous tissue (Figure 3B). Cartilage cells with weakly and moderately expressed polymorphism and morphological atypism could be seen interspersed in the chondroid matrix of the tumor (Figure 3C). The cells were large, with a reduced nuclear-cytoplasmic ratio. The cell nuclei were enlarged, sometimes atypical in shape, hyperchromic, with numerous binuclear cells (Figure 3D). The chondroid matrix of the tumor showed signs of myxomatosis, microfocal necrosis. The tumor freely occupied the bone marrow space, eroding the bone trabeculae, infiltrating Volkmann's and Haversian canals, and eroding the cortical bone layer. Regions of complete destruction of the cortical plate with infiltrative tumor growth into adjacent soft tissues were observed (Figure 3E). Regions characteristic of enchondroma were not detected. Histological report: taking into account the MR and CT imaging data, the diagnosis corresponds to a chondrosarcoma (G2) with the destruction of the cortical plate and infiltrative growth into the adjacent soft tissues (stage IIB according to Enneking). The tumor has been removed within the healthy tissue margins (type of resection - R0).
The patient regularly underwent follow-up examinations. Four years after surgery, the patient had no complaints or foreign body sensations. No signs of respiratory dysfunction were observed. The anterior chest wall had a normal configuration and there were no signs of implant instability. A good cosmetic (Figure 4A&4B) and oncologic (Figure 4C&4D) result was achieved
Figure 4A: Appearance of the patient 4 years after surgery (anterior and side views).
Figure 4B: Appearance of the patient 4 years after surgery (anterior and side views).
Figure 4C: Follow-up CT and radiography evaluation showed no signs of local relapse or metastases at four years of follow-up.
Figure 4D: Follow-up CT and radiography evaluation showed no signs of local relapse or metastases at four years of follow-up.
Bone chondrosarcomas are malignant tumors whose cells produce a cartilage matrix. In terms of the frequency of occurrence, chondrosarcoma takes the second place among primary malignant bone tumors after osteosarcoma, and, according to various authors, accounts for 10 to 25% of all primary bone sarcomas [4,22,23]. It is found in the age group from 5 to 90 years, mainly in middle and old age - most often between 40 and 60 years (about 60% of patients). It has a slightly higher frequency of occurrence in men. Any bone of cartilaginous origin can be affected. The most frequent localization (three quarters of patients) is in the bones of the trunk (pelvis, ribs) and the proximal ends of the femur and humerus . Among the malignant tumors that affect the sternum, chondrosarcomas are diagnosed most frequently [1,2,7]. Among 458 common chondrosarcomas diagnosed during the period from 1987 to 2009 at the pathology department at our institute, only 5 (1%) were localized in the sternum . Among the 2004 primary bone tumors in the registry of the St. James’s University Hospital (Leeds, West Yorkshire, England), 9 (0.45%) were localized in the sternum, of which 6 (0.3%) were chondrosarcomas .
The progression of chondrosarcomas varies from slowly growing tumors to aggressive metastatic sarcomas. Morphologically chondrosarcomas are divided into tumors of low (I), medium (II) and high (III) degrees of malignancy [4,22,23,26]. Almost 60–90% of chondrosarcomas belong to the category of low and moderate degree of malignancy . In the case presented in this article, a chondrosarcoma (G2, stage IIB according to Enneking) was diagnosed based on histopathological examination. Numerous approaches to reconstructive surgery of the anterior chest wall after resection of the sternum have been described in literature [7,10,12-15,19].
Titanium is a biocompatible, inert material with physical characteristics that allow to design robust individualized implants that closely replicate the shape of the sternum and chest wall. The implant structure can also be perforated without sacrificing stiffness, which facilitates its fixation. Additionally, titanium does not interfere with computed tomography or magnetic resonance imaging, allowing for safe and informative postoperative evaluation .
Gonfiotti and Santini (2009) described a case of surgical treatment of a patient with a chondrosarcoma, in which, after a total resection of the sternum, the defect was reconstructed with 4 metal plates attached to the ribs with titanium clips . А polytetrafluoroethylene sheet, which was fixed to the plates with non-absorbable suture material, was used to separate the chest organs from the metal plate. The postoperative period was uneventful. Six months after surgery, the implant was clinically and radiologically stable, there was no tumor recurrence, and no respiratory dysfunction was noted. In a study by Rocco et al, reconstruction of the anterior chest wall defect was performed using three metal plates and an omental flap. This approach allowed the authors to achieve full stability and to avoid complications .
Voronovich and Pashkevich (2011) reported on a case, where a perforated titanium plate was used for chest wall reconstruction after total sternum resection in a patient with a chondrosarcoma . The plate had a thickness of 15 mm and was manufactured in advance based on the patient’s radiographs. The follow-up period was 2 years. The patient had a complicated case of chondrosarcoma recurrence, which required surgical removal of the recurrent tumor nodes twice. No plate instability was observed during the course of treatment. The patient died due to metastatic spread of the tumor.
Demondion et al reported on a case of a 28-year-old patient with intraductal invasive carcinoma of the left breast with metastases to the sternum . After four courses of chemotherapy, the patient underwent radical mastectomy on the left, axillary lymphadenectomy and subtotal resection of the sternum. Reconstruction of the anterior chest wall was performed using an individualized titanium plate, manufactured based on a 3D model and CT data. Six months after surgery, the implant was clinically and radiologically stable, there were no signs of respiratory dysfunction. He and Huang reported on a case of a primary chondrosarcoma of the sternum in a 37-year-old woman . The patient underwent resection of the sternum with defect reconstruction using a titanium mesh and steel wire. At a 12-month follow-up the clinical and radiological results were good.
Aranda reported on the use of an individualized titanium prosthetic costo-sternal complex, also manufactured using additive technology and CT data, in a patient with a primary chondrosarcoma . No complications were observed in the early postoperative period. Mansour reported on 47 patients (24%) who underwent such surgeries and had complications during the hospital stay . The most common complications were pneumonia (27 patients, 14%), acute respiratory distress syndrome (ARDS) - 11 patients (6%) and flap loss - 10 patients (5%).
Weyant et al (2006) noted that severe complications, such as infection, splitting, flap loss and hematomas, were reported to occur in 8%–20% of cases . In our case, utilization of a stereo-lithographic model, 3D modeling, and manufacturing of an individualized titanium plate yielded excellent long-term clinical and cosmetic results, comparable to those of other authors. We believe that the described approach, as well as constantly developing technological advances can significantly improve the results of surgical treatment of patients with tumors of the sternum.
Additive technology allows to plan and execute the reconstructive stage following procedures involving major resection of the anterior chest wall due to aggressive tumors, leading to functionally and cosmetically excellent results and low rates of cardio-pulmonary complications.
At the last follow-up the patient was completely satisfied with the results of the surgery. She had no complaints of pain, or loss of function in her upper extremities. There were no complications associated with the surgery. The patient leads an active lifestyle and is very satisfied with the cosmetic effect. Full informed consent to undergo the described intervention was obtained from the patient.