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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_747_Библиотеки_им_академика_М_И_Перельмана
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34 Chest wall tumors
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Reconstruction
After completion of the resection, skeletal stabilization is carried out, followed by the soft tissue coverage if needed. Basic
surgical principles include adequate hemostasis and drainage
of the pleural cavity, protection of the pedicle flap from
extrinsic compression, approximation of tissues without tension, and measures that prevent air-leak.
In planning the reconstruction of chest wall defects several
factors should be considered:
1 The structure of the underlying defect
2 The location and size of the defect
3 The aim of the operation (palliation or cure)
4 The general condition of the patient
5 Previous surgical operation that may interfere with the
choice of the flap for reconstruction
6 Prior radiation therapy that may change the quality of the
skin and may require full thickness resection of the irradiated field.
SKELETAL RECONSTRUCTION
For limited resections of 5 cm or less, no rigid replacement is
necessary because usually no physiological effects will occur
after the resection. Larger defects can require some rigid support to obtain sufficient chest wall stabilization in a vulnerable area for respiratory function, to provide additional
support for the heart and lungs, to reduce the paradoxical respiration, and to maintain optimal chest function in patients
with a long life expectancy. Anterior or inferior defects of
more than three ribs usually need skeletal reconstruction.
Posterior defects under the scapula and the large muscles of
the back usually do not require bony stabilization. Sternal
and sternoclavicular resection causes significant paradox, and
reconstruction should be carried out also to protect the
underlying mediastinal structures.
Many different types of autogenous or synthetic materials
have been used over the years for skeletal reconstruction. The
ideal characteristics of the material for skeletal reconstruction
should be durability, availability, adaptability to any size and
shape, nonreactivity, resistance to infections, translucency to
X-rays, incorporation by body tissue, and ease of use. Bone
grafts have proved to be very durable. The ribs offer the best
bone grafts for chest wall reconstruction, they are rigid and
not rejected by the body. The disadvantages of using autogenous bone grafts are pain and the possible instability in the
area of the harvesting. A variety of alloplastic materials have
been used such as metal, stainless steel, tantalium, lucite, and
fiberglass. Although all these prostheses are able to prevent
flail chest, they are extremely rigid, in contrast to the chest
wall, and this issue creates special problems (erosion, destruction of the contiguous structure) and even extrusion through
the overlying skin or interiorly. Recently, synthetic materials
have been preferred, in the form of flexible meshes (Prolene,
Marlex). These prostheses differ in caliber and construction.
Marlex is a single knit fabric, rigid in only one direction and
stretchable in the opposite direction. Prolene is a double
stitch knit and is rigid in all directions. These meshes can be
sutured to the defect margins, tightly enough to be semirigid.
The mesh is incorporated into the chest wall by infiltration of
its interstices with fibrous tissue. Goretex is a soft tissue patch
impervious to air and water, ideal for a large defect associated
with pneumonectomy.
When a rigid chest wall replacement is necessary, the
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5
Marlex sandwich can be used. Two pieces of Marlex
mesh are prepared slightly larger than the defect. Methyl
methacrylate is then activated and mixed until it begins to gel
and then is spread over the one layer to a size smaller than the
defect. The second layer of mesh is placed over the methyl
methacrylate. The composite is now complete, and it will take
5–10 minutes to harden. During this time, the mesh can be
molded to the shape of the defect and sutured to the edges.
Muscle and skin closure are then performed. Seroma formation requiring long-term drainage has been associated with
the Marlex sandwich technique. Infection, if it occurs in alloplastic materials, dictates immediate removal of the prosthesis. In the meshes or the composite, infections first can be
treated conservatively using drainage and irrigation which is
usually effective most of the time. If removal is required after
6–8 weeks, a thick fibrous capsule formed by the body can be
rigid enough to prevent flail chest in most of the cases.
Operation 35
Polypropylene mesh
Methyl
methacrylate
cement
Methyl
methacrylate
mesh
'sandwich'
sewn in
place
SOFT TISSUE RECONSTRUCTION
After completion of the skeletal stabilization, if primary closure cannot be performed, muscle transposition is best to
accomplish soft tissue reconstruction. The most commonly
used muscle flaps are pectoralis major, latissimus dorsi, and
5
transverse rectus abdominis muscle (TRAM). Size and location of the chest wall defect and preservation of the blood
supply to the flap dictate the appropriate reconstruction.
Schematically, the thorax can be divided into three areas:
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In the sternal region the defects are usually full
6a–c
reconstruction because of the proximity of the skin to the
underlying bone. Pectoralis major is the most frequent flap
used in such defects. The pectoralis can be taken as a muscle
flap or as a myocutaneous flap because of the multiple perforators entering the skin through the muscle. The pectoral
branch of the thoracoacromial artery is the major blood supply. Release of the humeral tendon of the muscle provides a
wider mobilization and rotation. For larger defects located
over the mid sternum, pectoral muscle can be used bilaterally.
When the pectoralis major is not available and one of the
superior epigastric vessels is preserved, a transverse or vertical
rectus abdominis flap is a good alternative.
thickness and require skeletal and soft tissue
Thoracoacromial
artery
Lateral
thoracic
artery
Internal thoracic
artery
6a
6b
6c
Operation 37
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Anterior and lateral defects are the most
7a,b
flap of choice is the latissimus dorsi that can be used as a
myocutaneous flap or as a muscular flap. The thoracodorsal
artery, a terminal branch of the subscapular artery, is the
major blood supply, but it can be carried on the serratus collateral vascular plexus. Because of its long pedicle, a latissimus
dorsi flap can be used to cover any area of the chest.
common after chest wall tumor resection. The
7a
7b
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Posterior defects are infrequent because of the small
8
number of primary chest wall lesions in this area.
Moreover, more than one musculofascial layer separates the
skin from the chest wall, decreasing the need for additional
soft tissue coverage. The flap of choice is the latissimus dorsi.
The trapezius remains an alternative to cover small defects
located over the upper half of the back.
8
A. Right gastroepiploic
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artery pedicle
Operation 39
When muscle flaps are not available or large
9a–d
left epiploic vessels can be placed over bone grafts or mesh.
This tissue is very vascular; and when adequately mobilized, it
can reach any area of the thorax. The main disadvantage is the
need to open the abdomen to prepare it. Omentum will not
provide chest wall stability.
enough, the omentum based on the right or
9a
B. Left gastroepiploic
artery pedicle
9b
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C. Bipedicle
9c
9d
Further reading 41
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POSTOPERATIVE CARE
Although these patients generally require major chest wall
resection and reconstruction, the postoperative morbidity
and mortality rate are low. Complications are usually due to
infection and partial graft failure. Total graft failure is
uncommon. In the postoperative management three areas
require special attention: cardiovascular, respiratory, and
nutritional.
Common cardiovascular problems are blood pressure
irregularities, arrhythmias, congestive heart failure, and
myocardial infarction. Hypotension should be avoided and
can result in irreversible ischemia of the flaps used in reconstruction. Arrhythmias are common, especially in older
patients and are usually correlated to electrolyte imbalances,
hypoxia, and fluid overload. Congestive heart failure is usually the result of fluid overload. Pulmonary management is
directed to maintaining adequate respiratory function and to
recognizing and treating eventual complications. Early extubation, aggressive pulmonary toilet and physiotherapy, pain
control and prophylaxis for deep venous thrombosis represent the goals of postoperative care. The patient must be provided with excellent nutritional support; and if necessary,
supplemental parenteral or enteral nutrition can be
employed.
OUTCOME
Once the histological type of the tumor has been determined,
the appropriate therapeutic plans must be prepared. Most of
the primary chest wall tumors can be treated by surgical
resection as first line of treatment. In selected cases, preoperative or adjuvant chemotherapy, radiation, or a combination
of both can play an important role.
Chondrosarcoma is the most common malignant tumor,
representing 20% of all chest wall tumors. Chondrosarcomas
are usually solitary and localized at the level of the costochondral or sterno-chondral junction. The natural history of
this tumor usually consists of slow growth and local recurrence after resection. The 10-year overall survival rate of a
series from Memorial Sloan Kettering was 64%; 96% for
patients undergoing wide excision, 65% after local excision,
and only 14% after palliative resection. This tumor is
extremely radio- and chemo-resistant.
Osteogenic sarcoma occurs mainly during childhood and
adolescence, and it is associated with typical cortical destruction, periosteal elevation, and extra-osseous extension. This
tumor is highly vascularized; and when vascular invasion
occurs, it leads to early pulmonary metastases. For these rea-
sons, protocols of neoadjuvant chemotherapy and adjuvant
chemotherapy plus radiation protocols have been proposed.
Although survival advantages have not been documented, a
decrease in local recurrence rate has been observed with a
multi-modality therapy regimen.
Plasmacytoma represents 15–30% of all chest wall tumors,
presenting often in middle-age to older patients. This tumor
is very responsive to chemotherapy and radiation, and the
only role for surgery is the diagnosis. The majority of patients
unfortunately develop multiple myeloma. Overall 5-year survival rate ranges from 37% to 45%.
Soft-tissue sarcomas represent 20% of malignant lesions
of the chest wall. Surgery alone is associated with a high rate
of local recurrence (20%). Recent investigations have evaluated the impact of adjuvant therapies (radiation with or without chemotherapy). In the National Cancer study, the overall
survival after a multimodality approach was 59% at 5 years
with a local recurrence rate of 16%.
Desmoid tumors (low grade fibrosarcoma) are well-differentiated fibrosarcomas. After radical resection, the 10-year
survival rate is 95% with a recurrence rate of 30% at 5 years.
Ewing’s sarcoma is relatively radiation-sensitive. This
tumor is markedly vascular with large areas of necrosis.
Despite radiosensitivity, the prognosis before the advent of
chemotherapy was poor (5–15% 5-year survival). Currently,
surgery is considered the first line therapy followed by local
radiation and chemotherapy. Local control of the disease is
usually excellent, and disease-free survival rate is about 50%
after 3 years.
FURTHER READING
Abbas AE, Deschamps C, Cassivi SD, Nichols FC 3rd, Allen MS, Schleck
CD, Pairolero PC Chest-wall desmoid tumors: results of surgical
intervention. Annals of Thoracic Surgery 2004; 78: 1219–23;
discussion 1219–23.
Allen MS. Chest wall resection and reconstruction for lung cancer.
Thoracic Surgery Clinics 2004; 14: 211–16.
Gross JL, Younes RN, Haddad FJ, Deheinzelin D, Pinto CA, Costa ML.
Soft-tissue sarcomas of the chest wall: prognostic factors. Chest
2005; 127: 902–8.
Mansour KA, Thourani VH, Losken A, Reeves JG, Miller JI Jr, Carlson GW,
Jones GE. Chest wall resections and reconstruction: a 25-year
experience. Annals of Thoracic Surgery 2002; 73: 1720–5; discussion
1725–6.
Shrager JB, Wain JC, Wright CD, et al. Omentum is highly effective in
the management of complex cardiothoracic surgical problems.
Journal of Thoracic and Cardiovascular Surgery 2003; 125: 526–32.
Warzelhan J, Stoelben E, Imdahl A, Hasse J. Results in surgery for
primary and metastatic chest wall tumors. European Journal of
Cardiothoracic Surgery 2001; 19: 584–8.
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Anterior mediastinal lesions
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SHINICHIRO MIYOSHI MD, PhD
Professor and Chairman, Department of Cardiothoracic Surgery, Dokkyo University School of Medicine, Mibu, Tochigi, Japan
4
Anterior mediastinal lesions requiring surgical treatment are
usually myasthenia gravis (MG) or thymic tumors. A thymectomy is most frequently used, and occasionally a resection of
the surrounding organs is performed in advanced malignancy. This chapter describes extended thymectomy for MG
patients and surgical treatment for an invasive thymoma,
with special reference to resection and reconstruction of the
great vessels.
HISTORY
The effectiveness of a thymectomy for MG was first reported
by Blalock in 1939. Because he used a median sternotomy,
this approach was adopted and used for a long period of time.
A transcervical thymectomy was later advocated in 1966 by
the Mount Sinai Hospital group as a less invasive procedure.
In 1973, at Osaka University Hospital, Masaoka et al. established the ‘extended thymectomy’ – en bloc resection of anterior mediastinal adipose tissue, including the thymus, by
means of a median sternotomy. Since then, extended thymectomies have been performed as a standard procedure at our
institution.
PRINCIPLES AND JUSTIFICATION FOR
MYASTHENIA GRAVIS
Although the exact role of the thymus gland in the pathogenesis of MG has not been elucidated, several lines of evidence
suggest that it plays a central role in MG, and a thymectomy
has been reported to be effective in treating the disease.
A transcervical thymectomy yields a favorable outcome in
terms of the cosmetic results of the incision, low morbidity,
and minimal hospital stay required. This approach, however,
achieves a less complete thymectomy than a transsternal
thymectomy. Masaoka et al. reported that repeated operations after ineffective cervical thymectomies revealed a residual thymus in all cases, and complete removal produced
clinical improvement in MG. In 1975, they also noted the
frequent existence of thymic tissue in anterior mediastinal
adipose tissue around the thymus and advocated an extended
thymectomy through a median sternotomy. In 1981, the
results of this procedure were compared with those for a
transsternal thymectomy without adipose tissue resection
and a transcervical thymectomy. That study demonstrated
the superiority of an extended thymectomy over other procedures.
Since 1987, Jaretzki and colleagues have advocated a ‘max-
imal thymectomy’, which adds a resection of fatty tissue
in the cervical and hilar regions through a T-shaped
cervical/sternal incision. We do not favor enlarging the
amount of adipose resection beyond that of an extended
thymectomy, because maximal thymectomy has not been
shown to produce better results than extended thymectomy.
Controversy remains regarding the indication of thymectomy for elderly patients, pediatric patients, patients with an
ocular type of lesion, or patients with a long duration of disease. An extended thymectomy has been reported to be effective in these patients; however, and those factors do not seem
to be a contraindication. An extended thymectomy through a
median sternotomy can also be used for thymoma resection,
which is frequently performed in MG patients.
PREOPERATIVE ASSESSMENT AND
PREPARATION FOR MYASTHENIA GRAVIS
Weakness and fatigue with activity are the hallmarks of MG.
The ocular muscles are most frequently affected, which leads
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