Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5181_Библиотеки_им_академика_М_И_Перельмана.pdf
5 Orthopedic Infections
101
Chen AF, et al. What’s new in musculoskeletal infec-
tion: update across orthopaedic subspecialties. JBJS.
2017;99(14):1232–43.
Kocher MS, Zurakowski D, Kasser JR. Differentiating
between septic arthritis and transient synovitis of the hip
in children: an evidence-based clinical prediction algo-
rithm. J Bone Joint Surg Am. 1999;81(12):1662–70.
https://doi.org/10.2106/00004623-199912000-00002.
PMID: 10608376.
Olsen MA, et al. Risk factors for surgical site infec-
tion following orthopaedic spinal operations. JBJS.
2008;90(1):62–9.
Rasouli MR, et al. Risk factors for surgical site infec-
tion following total joint arthroplasty. JBJS.
2014;96(18):e158.
Connell MC. In: Wiesel SW, Delahay JN, editors.
Essentials of orthopedic surgery, vol. 615. NewYork:
Springer; 2007.
Flow Investigators. A trial of wound irrigation in the ini-
tial management of open fracture wounds. N Engl J
Med. 2015;373(27):2629–41.
Tumors oftheMusculoskeletal
System
JonathanDay andBrockAdams
6
Background
Both benign and malignant tumors can arise
from mesenchymal soft tissue or bone of the
extremities and axial skeleton. All tumors of
the musculoskeletal system arise from one of
the following histological tissues: bone (osteoid forming tumors), cartilage (chondroid
forming tumors), muscle, or brous connective
tissue. In addition, tumors can rarely arise from
arteries or nerves.
The vast majority of tumors are benign.
Malignant tumors of the musculoskeletal system
are termed sarcomas, which comprise about 80
different types arising from mesenchymal or
connective tissues [1]. It is estimated that roughly
16,000 new cases and 6000 deaths are attributed
to sarcomas annually in the USA. Still, this
J. Day
MedStar Georgetown Orthopedic Institute,
Georgetown University School of Medicine,
Washington, DC, USA
Department of Orthopedics, MedStar Georgetown
University Hospital, Washington, DC, USA
B. Adams (*)
MedStar Georgetown Orthopedic Institute,
Georgetown University School of Medicine,
Washington, DC, USA
Department of Orthopedics, MedStar Washington
Hospital Center, Washington, DC, USA
e-mail: Brock.W.Adams@gunet.georgetown.edu
accounts for less than 1% of all malignant cancer
diagnoses [2].
Contrary to most malignant diagnoses that
occur in the later decades of life, most bone sarcomas (osteosarcoma and Ewing’s sarcoma)
occur during childhood or adolescence. Soft tissue sarcomas tend to be found starting in the third
decade of life and become more common as age
increases. Bone tumors typically present with
pain, while soft tissue tumors tend to present as a
painless mass.
It is fundamental for orthopedic surgeons to
have a sound understanding of musculoskeletal
tumors. This includes an understanding of the
general workup and to the ability to determine
which patients should be referred to a subspecialized orthopedic oncologist. Early detection,
combined with proper techniques of diagnosis
and treatment, can dramatically improve the
chances of achieving functional limb salvage
and minimizing morbidity. Advances in imaging, chemotherapy, and radiation therapy, coupled with a better understanding of the
biological behavior of mesenchymal neoplasms, have led to a rational basis for diagnosis, staging, and treatment.
The aim of this chapter is to provide an up-todate, comprehensive review of the most common
benign and malignant tumors of the musculoskeletal system, as well as the general workup, diagnosis, treatment options, and prognosis.
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2024
W. F. Postma et al. (eds.), Essentials of Orthopedic Surgery,
https://doi.org/10.1007/978-3-031-66215-7_6
103
104
J. Day and B. Adams
Natural History ofBone andSoft
Tissue Tumors
Mesenchymal tumors have characteristic patterns
of behavior and growth that help distinguish it
from other tumors. These unique features form
the basis for tumor staging and treatment.
Biology andGrowth
Sarcomas grow in a centrifugal fashion with the
youngest and most viable cells toward the
periphery. They tend to push the normal tissue
away as they expand as opposed to many carcinomas, which inltrate and invade the surrounding tissue. In contrast to benign lesions that often
are surrounded by a true capsule, malignant
lesions are surrounded by a pseudocapsule
formed by compressing the normal tissue surrounding the lesion as it grows. This is composed
of a brovascular zone of reactive tissue that
contains some tumor cells within it. The thickness of this layer can vary by degree of malignancy and histologic subtype.
High-grade sarcomas characteristically have
poorly dened reactive zones. In addition, tumor
nodules that are not in continuity with the main
tumor may be present in tissue that appears normal. Low-grade sarcomas rarely form tumor nodules beyond the reactive zone.
Local anatomy inuences the growth of sarcomas by setting natural boundaries to extension. In
general, sarcomas take the path of least resistance. Fascial boundaries such as the periosteum,
compartmental fascia, or a vascular sheath form
effective barriers. Bone tumors grow via three
mechanisms: compression of normal tissue,
resorption of bone by reactive osteoclasts, and
direct destruction of normal tissue. Benign bone
tumors grow and expand via the rst two mechanisms, whereas malignant ones expand via direct
tissue destruction. In addition, benign tumors are
usually unicompartmental, meaning they remain
conned to and may expand the bone in which
they reside. In contrast, malignant bone tumors
are often bicompartmental, meaning they destroy
the overlying cortex and push directly into the
adjacent soft tissue. With this concept in mind,
soft tissue tumors may start in one compartment
(intracompartmental) or between compartments
(extracompartmental). This determination of
anatomic compartments is especially important
when considering limb-preservation surgery.
Five Patterns ofTumor Behavior
On the basis of biologic considerations and natural history, all bone and soft tissue tumors, benign
and malignant, may be classied into ve categories, each of which shares certain clinical characteristics and radiographic patterns. Treatment of
tumors is also similar for tumors in each group.
The ve categories are as follows:
1. Benign/Latent
These lesions grow slowly during the nor-
mal development of the individual. As the
growth of the individual stops, the growth of
the lesion stops and sometimes resolves spontaneously. These lesions are typically not
symptomatic and as a general rule do not
progress to malignancy. Observation is the
most common course of treatment. Examples
include lipomas and brous cortical defects.
2. Benign/Active
These lesions exhibit progressive growth
and bone lesions are often symptomatic.
Treatment is with excision for soft tissue lesions
or curettage for bone lesions. It is not necessary
to remove the reactive zone. Chondroblastoma
and osteoid osteoma are examples.
3. Benign/Aggressive
These lesions are locally aggressive but do
not metastasize (with the notable exception
below). Tumor can extend beyond the capsule
and into the reactive zone. Treatment aims to
remove the reactive zone by resecting a cuff
of normal tissue for soft tissue tumors. For
bone lesions this is approximated by removing the reactive zone with a high-speed burr
and using a physical or chemical adjuvant to
kill remaining tumor cells. Giant cell tumor of
bone (benign but can metastasize) and bromatosis are in this group (Fig.6.1).
6 Tumors oftheMusculoskeletal System
Fig. 6.1 A giant cell tumor of bone with a secondary
aneurysmal bone cyst. This represents an aggressive
benign lesion. Note the easily recognizable sharply
dened border. Plain radiographs are the most important
study in the diagnosis of bone tumors
4. Malignant, Low Grade
These lesions have the ability to metasta-
size but do so at a low rate. Tumor can expand
beyond the compartment and tumors cells are
present in the reactive zone. Treatment
involves removal of the lesion with a cuff of
normal tissue, but no adjuvant therapy is
necessary. Examples are parosteal osteosarcoma and low-grade soft tissue sarcomas.
5. Malignant, High Grade
These lesions grow rapidly and metasta-
size early and at a high rate. These tumors
may have a poorly dened pseudocapsule
and tumor nodules can extend beyond the
reactive zone into the normal tissue. Excision with a cuff of normal tissue is necessary
for surgical treatment. Chemotherapy is
required for bone tumors and some soft tissue tumors to lessen the rate of metastasis.
Radiation is required for soft tissue tumors to
reduce the chance of local recurrence. Classic intramedullary osteosarcoma and undifferentiated pleomorphic sarcoma (UPS) are
in this category.
105
Mechanisms ofTumor Spread
Unlike carcinomas, bone and soft tissue sarcomas disseminate almost exclusively hematogenously. Because of this, the lungs are by far the
most common site of metastatic spread with
80–90% of metastases found in the lungs. Bone
is the next most common site of metastasis. Both
bone and soft tissue sarcomas can spread via the
lymphatic system to regional lymph nodes. The
rate of lymphatic spread varies by disease entity,
but in general is just under 5%.
The histologic hallmark of malignant sarcomas is their potential to break through the pseudocapsule to form satellite lesions. Discontinuous
tumor, commonly referred to as a skip metastasis,
is a tumor nodule located in the same bone or
compartment as the primary tumor but is not contiguous with it.
The mechanism of spread and common sites
of metastatic spread are important to keep in
mind when evaluating a patient with a sarcoma
and guide the choice of imaging studies necessary to determine the stage of disease.
Clinical andRadiographic
Evaluation
Clinical Evaluation
It is often said that the importance of the clinical
history and physical examination should not be
overlooked, and this is certainly true in the evaluation of musculoskeletal tumors. The location of
a tumor, the rate at which it is growing, pain, or
any history of trauma are all key points to obtain
from the history. On examination it is important
to note the size of the mass, its relation to surrounding structures, whether it appears to be
supercial or deep, tenderness, the appearance of
the overlying skin, and whether it is rm or soft.
While mesenchymal tumors spread hematogenously for the most part, an examination of the
regional lymph nodes should be included.
Special attention should be paid to the characteristics of pain. In bone tumors, pain is an
important feature distinguishing aggressive or
106
J. Day and B. Adams
malignant tumors from more latent lesions. Pain
that arises from a bone lesion typically is
described as a dull aching type pain. It is often
present at rest as well as with activity and classically wakes the patient up at night. This is in
contrast to more common musculoskeletal
sources of pain which are typically worse with
certain types of activity and improve with rest.
A lesion in the proximal humerus of a patient
presenting with vague, dull pain waking them
up at night and full range of motion of the shoulder is worrisome. A lesion in the proximal
humerus of a patient presenting with pain with
overhead activity after an injury is not worrisome. Interestingly, the same does not hold true
for soft tissue tumors. The most common presentation of a soft tissue sarcoma is a painless,
enlarging mass. While there are more painful
benign soft tissue tumors than malignant ones,
both benign and malignant soft tissue tumors
may present as painless or painful masses.
Radiographic Evaluation
X-Rays
Conventional anteroposterior (AP) and lateral
radiographs remain essential in the initial characterization and diagnosis of musculoskeletal
tumors. Further advanced imaging is often dictated by initial plain radiographic ndings. Proper
interpretation of a lesion on X-rays can be guided
by answering four classic questions proposed by
Dr. William F.Enneking:
1. What is the anatomic location and extent of
the lesion?
2. What is the lesion doing to the bone?
3. What is the bone doing to the lesion?
4. What is the tissue type of the lesion?
Distinctions between benign, aggressive,
and frankly malignant lesions can be made on
the basis of this analysis. Benign lesions have
well- dened borders often with a surrounding
rim of sclerotic bone and do not penetrate the
cortex. In contrast, malignant lesions have
poorly dened sometimes permeative borders
and can destroy the cortex. Many bone lesions
in particular have a characteristic appearance
on X-ray and a diagnosis can often be made
based off the X-ray along. In general, plain
radiographs are the most important imaging
study when determining the type of bone tumor
(Fig.6.2).
Computed Tomography
Computed tomography (CT) allows highresolution cross-sectional imaging of bone.
While it can be used to evaluate soft tissue structures, soft tissue tumors, and the extent of a tumor
both in the intramedullary space and in the soft
tissue, CT is most helpful looking at the calcied
portions of the bone. Thinning or scalloping of
the cortex and subtle periosteal reaction are best
seen on CT. Similarly, faint matrix production
may be difcult to discern on plain X-ray, but
relatively easy to see on CT.CT can also be helpful for preoperative planning purposes, especially
in more complex structures such as the pelvis. A
CT of the chest is often used for staging
purposes.
Magnetic Resonance Imaging
Magnetic resonance imaging (MRI) provides
detailed multiplanar information of both bone
and soft tissue. It gives great visualization of anatomic compartments, vessels, other soft tissues,
and bone. MRI shows the extent of the tumor in
both the bone and soft tissue and its relation to
the surrounding structures in great detail. It is
valuable for preoperative planning. While MRI
can be helpful from a diagnostic standpoint, diagnosis typically cannot be made on the basis of the
MRI characteristics alone. An MRI done to evaluate a tumor should include a true T1 sequence, a
T2 sequence with fat suppression, and a T1 postcontrast image with fat suppression (Fig.6.3).
Nuclear Medicine
Bone scintigraphy can be helpful in assessing
the primary lesion and to screen for distant
metastasis. The delayed phase of a technetium-99 scan is used most commonly. While
a
6 Tumors oftheMusculoskeletal System
Adamantoma
Osteoid osteoma
Diaphysis
Chondromyxoid
fibroma
107
Round cell lesions:
Ewing sarcoma
Histiocytic lymphoma
Myeloma
Fibrous dysplasia
Fibrosarcoma
Osteosarcoma
Metaphysis
UPS
Physis
Epiphysis
Chondroblastoma
Fig. 6.2 Schematic of typical locations of common bone
tumors. The anatomic location, whether diaphyseal,
metaphyseal, or epiphyseal, is one of the most important
the level of uptake compared to the surrounding bone can be used to distinguish between
latent and more aggressive lesions, the level of
discrimination is relatively low. Because of
this, bone scan is used primarily to screen for
metastatic disease.
Positron Emission Tomography (PET) is used
to measure the metabolic activity of a lesion.
F-18 ouro-2-deoxy-D-glucose (FDG) is most
commonly used. Similar to bone scan, there is a
correlation between uptake on PET and how
aggressive the tumor is. It can be used to assess
treatment response. PET is used less frequently
for staging in sarcoma than some other malignancies, owing to the relatively predictable pattern of
spread, but use of PET for sarcoma is becoming
more widespread.
Enchondroma
Osteochondrom
ABC
GCT
determinants of tumor type. Cortical, medullary, or eccentric location is also important. One should always pay special attention to the presence of matrix formation
Ultrasound
Ultrasound can be used to evaluate soft tissue
tumors. While it is operator dependent, it can
often be obtained more quickly than axial imaging. Using Doppler, it can be used to assess the
vascularity of the lesion. Ultrasound can also be
used to guide needle placement for biopsy.
Angiography
While the need for true angiography has
decreased as the image quality and availability of
MRI has improved, it is sometimes still the best
way to assess the vascularity or intravascular
involvement of a tumor. Preoperative embolization of highly vascularized tumors prior to surgical resection can signicantly reduce blood loss
and intraoperative morbidity.
108
a b d
c
J. Day and B. Adams
Fig. 6.3 Radiographic (a), T1 weighted coronal MRI (b),
axial CT (c), and whole body technetium bone scan (d) of
a patient with a grade-2 chondrosarcoma. While the plain
radiograph is most important diagnostically (black arrow),
MRI shows the tumor extent in the bone and soft tissue
Staging
Staging of a bone or soft tissue sarcoma is the
process of determining the local extent of the
tumor and any potential sites of distant metastasis. If there is clinical or radiographic suspicion
of an aggressive or malignant tumor, staging
studies should be performed prior to biopsy.
Staging can guide proper location and method of
biopsy. X-rays should always be a part of the
local imaging. Beyond this, initial staging typically includes MRI of the entire bone or region
affected, CT of the chest, and a technicium-99
whole body bone scan.
(white arrows), CT shows the faint chondroid matrix and
abnormal cortex (red arrow), while bone scan shows
increased uptake at the lesion and screens for additional
lesions (blue arrow)
Staging Systems
The purpose of a surgical staging system is to
organize patients into groups that correlate with
overall outcome and survival. This has prognostic value and can guide treatment decisions for
both physicians and patients. There are two
widely used staging systems in orthopedic oncology. Historically, the most widely used system is
the Musculoskeletal Tumor Society (MSTS) system based on the system proposed by William
Enneking [3]. The system from the American
Joint Committee on Cancer (AJCC) is the other
widely used system and is the most common sys-
6 Tumors oftheMusculoskeletal System
109
tem used in specialties outside of orthopedics.
Stage in both systems correlates with overall survival with higher stage having a worse
prognosis.
The MSTS system takes three factors into
account. i.e., the tumor grade, local extent, and
the presence or absence of metastatic disease.
The same system is used for both bone and soft
tissue sarcomas.
1. Surgical Grade
The histological grade of a lesion correlates with its growth rate or aggressiveness.
Tumors are divided into two groups—low
grade versus intermediate and high-grade.
Low-grade lesions are malignancies with low
potential to metastasize.
Table 6.1 AJCC (8th edition) staging system for soft tis-
sue sarcomas
G, Histologic
grade
T, Primary
tumor
N, Regional
node
M, Distant
metastasis
Stage groups IA G1, T1, N0, M0
G1 Well-differentiated, low grade
G2 Moderately differentiated,
high grade
G3 Poorly differentiated, high
grade
T1
≤5cm in greatest dimension
T2
>5cm and ≤10cm in greatest
dimension
T3
>10cm and ≤15cm in
greatest dimension
T4 Tumor >15cm in greatest
dimension
N0 No regional lymph node
metastasis
N1 Regional lymph node
metastasis
M0 No distant metastasis
M1 Distant metastasis
IB G1, T2/3/4, N0, M0
II G2/3, T1, N0, M0
IIIA G2/3, T2, N0, M0
IIIB G2/3, T3/4, N0, M0
IV Any G, Any T, N1, M0
Any G, Any T, Any N, M1
2. Surgical Site
Anatomic site is either intracompartmental
or extracompartmental. A compartment is
dened as an anatomic space bound by natural barriers to tumor extension such as a single
bone. More aggressive tumors tend to expand
outside of their original compartment.
3. Metastatic Disease
The presence of metastatic disease is a
poor prognostic factor. The 8th edition of the
AJCC staging system is slightly different for
bone and soft tissue sarcomas [4]. It uses
grade, tumor size, the presence of discontinuous tumor (for bone sarcomas), and the presence of lymph node or distant metastasis
(Tables 6.1 and 6.2). Recent literature has proposed alternative staging systems which con-
Table 6.2 AJCC (8th edition) staging system for bone
sarcomas
G, Histologic
grade
T, Primary
tumor
N, Regional
node
M, Distant
metastasis
Stage groups IA G1, T1, N0, M0
G1 Well-differentiated, low grade
G2 Moderately differentiated,
high grade
G3 Poorly differentiated, high
grade
T1
≤8cm in greatest dimension
T2 >8cm in greatest dimension
T3 Discontinuous tumor in
primary bone site
N0 No regional lymph node
metastasis
N1 Regional lymph node
metastasis
M0 No distant metastasis
M1a Distant metastasis—lung
M1b Distant metastasis—other
sites
IB G1, T2/3, N0, M0
IIA G2/3, T1, N0, M0
IIB G2/3, T2, N0, M0
III G2/3, T3, N0, M0
I VA Any G, Any T, N0, M1a
IVB Any G, Any T, Any N, M1b
110
J. Day and B. Adams
sider other factors such as histologic grade,
tumor size, and anatomic depth [5].
Biopsy
Biopsy Techniques
The planning and technique of a biopsy are very
important. Biopsies should be performed after
staging studies are obtained [6]. Biopsy should be
done in the plane of eventual tumor resection and
should be closely coordinated by the treating physician. Biopsy should be taken from the periphery
of the lesion where the most viable tissue and
immature cells are found. In a bone lesion, the
soft tissue component should be biopsied if present. Care should be taken not to contaminate
potential tissue planes or aps that will compromise the management of the lesion. A poorly
planned biopsy can result in delayed diagnosis,
larger denitive procedures, increased need for
ap coverage, and higher rate of amputation [7].
Core-Needle Biopsy
To minimize contamination and morbidity, coreneedle biopsy of soft tissue and bone sarcomas is
generally recommended over incisional biopsy
(Fig.6.4). Core-needle biopsy provides adequate
tissue for diagnosis with accuracy similar to open
biopsy. The risk of seeding the biopsy tract is
lower [8]. In contrast to ne-needle aspiration,
core-needle biopsy preserves the intercellular
architecture in addition to the cellular appearance, which is important in the histologic diagnosis of mesenchymal neoplasms.
Imaging should be performed prior to biopsy.
Image guidance with either CT or ultrasound can
be used as needed and can be useful in tumors in
close proximity to neurovascular structures, areas
of complex anatomy, or when signicant heterogeneity or evidence of necrosis is present on
imaging.
Incisional Biopsy
While a core-needle biopsy is sufcient in the
majority of cases, an open, or incisional, biopsy
may still be indicated when core-needle biopsy is
not diagnostic or a high volume of tissue is necessary. This requires proper technique to minimize
contamination. While the biopsy should always
be done in the plane of eventual resection, this is
most important in an open biopsy. A tourniquet is
generally advised to help facilitate visualization
of tumor and meticulous hemostasis should be
maintained. Tissue dissection should be minimized, and dissection of neurovascular structures
should be avoided.
Excisional Biopsy
Some small, supercial lesions may be removed
as an excisional biopsy. This involves excising
the lesion with a wide margin or a cuff of normal
tissue. Criteria to consider excisional biopsy
include small size, supercial location or relatively close to the fascia, minimal morbidity, and
neoadjuvant therapy would not change surgical
approach or outcomes.
Fig. 6.4 Clinical photograph of core-needle and specimen. Multiple specimens from different portions of the
tumor can be obtained through one biopsy site. The orthopedic oncologist should either perform or oversee placement of the needle
Overview ofSurgical Procedures
Surgical removal—including curettage, resection, and amputation—is the mainstay of treating
musculoskeletal tumors (Fig.6.5). The extent of
the surgical procedure necessary is determined
by both tumor type and the local anatomy. A classication scheme of surgical procedures based on
6 Tumors oftheMusculoskeletal System
Radical
Wide
Marginal
Intralesional
Fig. 6.5 Schematic diagram illustrating different resection types
the surgical plane as well as method of resection
is summarized below. This provides a standardized terminology when discussing surgical treatment of both bone and soft tissue tumors and is
widely used in clinical practice as well as the
published literature.
1. Intralesional procedures involve opening the
pseudocapsule and removing the tumor in
piecemeal fashion. Biopsies are by denition
intralesional. Most benign bone tumors are
treated with an intralesional procedure or
curettage.
2. Marginal procedures involve opening the
pseudocapsule and removing the mass in a
single piece. This leaves the pseudocapsule
behind. Marginal resections are not used for
sarcomas since tumor cells are known to
reside in the pseudocapsule. Low-grade lipomatous soft tissue masses are typically
removed with a marginal resection.
3. Wide (intracompartmental) procedures,
also referred to as en bloc resections, involve
resecting the entire lesion including the
surrounding pseudocapsule and a cuff of normal tissue. There is no specic thickness of
normal tissue necessary to perform a wide
resection. As opposed to carcinomas, which
often require a specic margin measured in
111
centimeters, a wide margin in sarcoma is
dened as at least single layer of cells.
4. Radical (extracompartmental) procedures
involve resection of the entire compartment
(or compartments) involved by the tumor.
Although this term still appears in the literature, it most often is used because of differences in terminology and billing codes and
does not reect a true radical resection. A true
radical resection at this point is primarily historical in nature and is not necessary unless
done to achieve a wide margin as described
above.
It is important to note that all the above can be
performed via a limb-sparing approach or via
amputation. Amputation does not automatically
provide a wide margin. Both the local tumor
extent and the local anatomy dictates how a particular margin can be obtained.
In general, benign bone tumors can be adequately treated with either intralesional procedure (curettage) or a marginal excision. For
benign bone lesions, this typically involves making a cortical window and using curets to remove
the lesional material. A high-speed burr is then
used to remove the reactive zone. An adjuvant is
then often used to kill any remaining tumor cells.
This may be a cryoablation to freeze the tumor
cavity, use of an argon beam, or a chemical adjuvant such as phenol. Removing the reactive zone
and use of an adjuvant are important in reducing
the recurrence rate, which can be as high as 50%
for some tumors after a simple curettage
(Fig.6.6).
Malignant tumors as a rule should be excised
with a wide margin. Most tumors, 90–95%, can
be excised with a limb-sparing operation, but if a
wide margin cannot be safely obtained, amputation should be considered. As mentioned above,
there is no specic thickness of normal tissue that
must be maintained around the tumor to achieve
a wide margin. That being said, the biology of the
individual tumor type and its propensity for local
recurrence and the effectiveness of adjuvant
treatment in the form or radiation or chemotherapy should be taken into account when deciding
how aggressively to pursue limb salvage.