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248
Fig. 19.1 Plain lateral film of C2 body destruction by metasta-
sis of breast cancer in a 50 year old woman
19 Tu mor s
the vertebral artery (VA) (Fig. 19.4) [53], adjacent neu-
ral structures, and the oropharynx (Fig. 19.5) [77].
19.1.2 Therapeutic Remarks
Depending on tumor staging, histology, age, and
general patient status the consequent patient risk versus
benefit ratio can be evaluated. The final therapeutic
protocol can vary from observation with no therapy
(life expectancy less than 6 weeks) to radical, aggressive
surgery followed by radiation and chemotherapy.
Given the surgical focus of this book, it is important to
emphasize that any excision of tumor may impact the
statodynamic properties of the spine and in such cases,
necessitates appropriate spinal column reconstruction.
19.1.3 Surgical Oncologic Terms
compression, and is also good to determine multilevel
spine involvement. The use of gadolinium on
T1-weighted images enhances the tumor tissue and
allows delineation of normal and abnormal processes.
Evaluation of cervical tumors not only requires defining the extent of the lesion but also its relationship to
The terms used to describe the extent of surgical resection are a constant source of confusion. Often, one can
read that the resection was performed: “en bloc,”
“gross total,” or that there was a “radical resection.”
Also, the term “margin” often mixes concept of surgical margin with histological margins.
Fig. 19.2 Destruction of C2 by renal carcinoma metastasis. (a) Coronal plane CT reconstruction. (b) Anterior view 3D CT
19.1 Extradural UCS Tumors
249
Fig. 19.3 C2 affected by metastasis of renal carcinoma, notice
the canal compromise (patient from Fig. 19.2)
Fig. 19.5 Displacement of oropharynx in a case of anterior
prevertebral C2 chordoma spread shown on lateral contrast
swallow study
It is difficult to adapt the oncologic definitions used
in long bone and soft tissue pathologies for spine
surgery purposes. Single-piece removal of the whole
vertebra in the UCS is not possible due to the spinal
cord. Also, definition of an extracompartmental margin
of resection fails if the tumor reaches the extradural
space, which is in continuity through the whole spine.
It is clear that the surgical margin is the surgeon’s
subjective definition of the border of the tumor formed
by either a capsule or pseudocapsule of reactive tissue, or by a layer of healthy tissue surrounding infiltrative neoplasms. Conversely, the histological margin
can be objectively confirmed as tumor-free only by
the laboratory investigations of the specimen after
removal.
In concordance with others, we would like to define
the meaning of each term [45, 49, 133].
Respecting the surgical margin of the tumor during
resection:
Fig. 19.4 Narrowed vertebral artery passing through C2 chor-
doma with extracompartmental extend depicted on vertebral
angiogram
• Intra or endolesional (means the surgical margin of
the tumor is disrupted during the procedure)
• Marginal (means single-piece tumor removal along
its surgical border without margin violation)
• Wide (means single-piece removal of tumor sur-
rounded by continuous layer or cuff of healthy tissue)
250
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According to the method of resection, one can distinguish:
• Piecemeal resection (means successive, step wise
tumor removal - typical example is curettage)
• En bloc resection (means, tumor removal in one
piece regardless of its margins)
• Spondylectomy (means, removal of the whole verte-
bra regardless of the method used to do it)
In summary, if the tumor spreads from the body posterior through both pedicles, the oncologic wide margin
resection is not possible. Moreover, if the whole vertebra is considered as the malignant tumor compartment,
en bloc resection is not feasible in UCS (but is sometimes possible in lumbar region and may damage the
cauda equina, which can be justified in certain lesions
e.g.: osteogenic sarcoma or chordoma if the patient
accepts such morbidity).
19.1.4 Primary Bone Tumors of UCS
Primary bone tumors of the spine are relatively rare
comprising about 4.2% of all spine tumors [1, 16].
19.1.4.1 Benign Primary Bone Tumors
Benign lesions are less frequent than malignant
lesions in the UCS [14, 43, 77]. They occur predominantly in the second and third decades of life and
affect males twice as often as females [77]. The
tumors most commonly seen in the region of the cervical spine are osteomas (44%), osteoblastomas
(15%), and aneurysmal bone cysts (15%). Less frequently seen are eosinophilic granulomas (12%),
giant cell tumors (5%), and osteochondromas (5%)
[77]. Much rarer, and described in case reports are:
hemangiomas, fibrous dysplasia, and a few cases of
Gorham disease [76, 77]. Both, the atlas and axis
can be involved; however, C2 due to the larger cancellous bone content is much more frequently
affected.
Although benign tumors that occur in the cervical
spine are from a wide range of histological types, they
have many common as well as differentiating features
that will be described below.
Classification, Grading, and Staging
In order to properly evaluate the prognosis, treatment
feasibility and methods to follow outcomes, benign
tumors should be divided into similar groups. Therefore,
systems classifying tumors are necessary. The oncologic
staging of primary bone tumors, based on clinical features, radiographic patterns, and histological behavior
described for long bone neoplasms by Enneking et al.
[44, 45] has been adopted for benign primary bone spinal tumors [21, 77]. It distinguishes three stages of
benign and six stages of malignant primary spine tumors.
The classification system is named after Enneking.
Enneking Staging of Primary Benign Spine Tumors
S I first stage, latent, asymptomatic, well-bordered by a
true capsule
S II second stage, slowly growing, symptomatic, thin
capsule with reactive tissue
S III third stage, aggressive, rapid growth, symptomatic,
capsule discontinuous – absent, or reactive
pseudocapsule, invades neighboring compartments
A reproducible classification system that describes the
tumor extent, localization, and surgical accessibility
was proposed originally by Weinstein and was modified by Boriani et al. is named WBB surgical staging
(Weinstein-Boriani-Biagini surgical classification,
WBB) [21, 131].
WBB Surgical Staging
WBB system divides the transverse extension of vertebral tumors into 12 radiating zones (numbered 1–12 in
a clockwise order with no. 1 on the left side of the
spinous process) and 5 concentric layers (A–E concentric zones from the paravertebral extraosseous compartments (A) to the dural involvement (E) and the VA
foramen area (F)). These staging systems were tested
for observer reliability with very good intra-observer
reliability results; however, the inter-observer reliability was only moderate [34].
The Enneking and WBB staging status, together
with tumor histology obtained by biopsy can give us
an idea of potential treatment possibilities, the patient’s
19.1 Extradural UCS Tumors
251
prognosis and can also allow comparison of treatment
strategies, and outcomes between centers.
For example, a small osteoma of the right posterior
C2 arch can be classified as: osteoma, Enneking S1,
and WBB 11 B. This information is comprehensive
enough to consult the oncologic center, establish prognosis and treatment strategy. If dimensions of the
lesion measured on CT images are added, the information is complete for long-term follow-up and observation in conservatively treated patients.
Clinical Symptoms
The clinical symptoms of primary bone tumors are
nonspecific. The first symptom can be a constant or
episodic neck pain unusual in a young individual. The
symptoms are dependent on tumor location, its extent,
and the likely eventual pathologic vertebral fracture,
which can cause a simple radiculopathy or extend to
create significant myelopathy. In osteoid osteomas,
nocturnal pain is very characteristic and occurs in about
50% of patients [101]. Extracompartmental tumor
spread, such as from aneurysmal bone cyst, can cause
torticollis or even a palpable posterior neck mass.
Radiology
lesions (S2-3) necessitate early surgical management
to prevent clinical symptoms. Depending on the histology and surgical accessibility, radical tumor resection
is preferred. Puncture biopsy is often helpful prior to
the surgical procedure. In some lesions, endolesional
or marginal resection is sufficient; however, in aggressive tumors with a known tendency to recur, radical
resection to the extent that is allowed by anatomic
UCS complexity should be performed. Wide resections involving the stabilizing structures (body, pedicle, and facets) have to be followed by a single stage
UCS reconstruction. As many of the tumors can present in childhood, the growing potential of the immature spine must be considered. In these situations,
using largely autologous bone that is fixed without
growing restraints (wires often better than screws)
is required. All the approaches described in Chap. 4.
(posterior midline, high anterolateral, lateral, and transoral) can be used to reach the tumor mass. Direct or
indirect embolization can help in the treatment of vascularized tumors. Despite some tumors being benign,
there is often a tendency to recur and in some tumors
adjuvant therapy is recommended. Although evidence
is limited, focused radiotherapy is recommended in
osteoblastomas, aneurysmal bone cysts, and LCH
by some authors, especially in recurrent tumors [31,
47, 70]. Standard chemotherapy has not shown much
effect in these tumors although bisphosphonates are
sometimes tried.
Aggressive osteolytic neoplasms can easily be seen on
plain radiographs, usually as a result of deformity or
vertebral body collapse; however, most of the benign
tumors are more accurately detected by CT or MRI. The
CT scan with bone windows defines bony pathology
precisely. The MRI is less effective in evaluating bony
anatomy but can clearly depict the relationship of the
tumor to the adjacent soft tissue and neural structures.
In growing tumors with a reactive pseudocapsule, a
radioisotope bone scan can reveal the hot spot leading to
further investigations. As in other pathologies of the
UCS, all the anatomy must be clearly understood if surgical decompression and reconstruction are planned.
General Treatment Strategy
S1 tumors usually do not need treatment until a pathologic fracture or severe pain occurs; however, growing
Osteoid Osteomas and Osteoblastomas
Osteoid-producing tumors such as osteoid osteomas
and osteoblastomas are rare lesions in the UCS level.
Osteoblastomas are seen less frequently than osteoid
osteomas with an incidence of 10–25% of primary
osseous spine tumors [6]. They affect young people
with a male predominance of 2:1. Osteomas occur predominantly within the posterior elements, the arches,
facet joints, and pedicles [18, 77] but are occasionally
found in the vertebral body [118]. Both types of tumors
are histologically similar, however osteoblastomas are
more aggressive, larger (more than 20 mm), often
involve both the anterior and posterior vertebral segments and can recur in up to 20% [76]. There is only
one report of osteoma conversion to osteoblastoma in
the literature [25], and in reviewing the literature there
is not a clear definition of the differences between the
252
two tumor types. Only the extremes, small osteomas
and large, spreading osteoblastomas can be distinguished clearly from their radiological appearance.
Diagnosis
The clinical symptoms are often non-specific. The
patients present with neck pain, classically with nocturnal peaks that responds to salicylates and NSAIDs.
Osteoblastomas can be often visible on plain X-rays as
an osteolytic lesion and can frequently cause vertebral
body deformity (Fig. 19.6), however the small osteoid
osteomas do not. CT scan is very useful in distinguishing the tumor type. While osteoma can typically be
seen as sclerotic bone with a round radiolucent ovoid
exophytic mass (Fig. 19.7), osteoblastoma is detected
as a multilocular, cavernous lytic structure (Fig. 19.8)
or as aggressive large osteoma (larger than 20 mm)
without a sclerotic border.
Treatment Strategy
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Fig. 19.7 Osteoma of the C2 lamina with an internal exophytic
extend shown on axial CT
Currently, intralesional excision (curettage) of the
nidus is the widely accepted treatment of osteomas,
even in the UCS area [89]. Nevertheless, radiofrequency ablation has been successfully used in their
treatment [28, 29, 74]. Those who are asymptomatic or
respond to pharmacological management with aspirin
or NSAIDs can be simply observed [26, 91].
Osteoblastomas also typically involve the posterior elements of the spine, but due to their larger size
and aggressive behavior may extend into the pedicle,
Fig. 19.6 Osteoblastoma of C6 in a 16 year-old female. Osteolytic
process led to body collapse – “vertebra plana” appearance
Fig. 19.8 Osteoblastoma of C6 (patient from Fig. 19.6) show-
ing the whole vertebra involvement and honeycomb structure.
Axial CT scan
19.1 Extradural UCS Tumors
vertebral body, and can compromise the spinal canal
[59]. In 1964, Lichtenstein and Sawyer first reported a
series of 20 osteoblastomas and concluded that these
tumors throughout the skeletal system should generally be treated, conservatively. However, they emphasized that osteoblastomas located in the spinal axis
should be surgically decompressed and then irradiated
[79]. The recurrence rate for osteoblastomas after simple resection has been reported between 10% and 19%
[66, 81]. In the largest review of 306 spinal osteoblastoma cases collected at Mayo Clinic over 17.5 years,
complete treatment and clinical follow-up was only
available for 75 patients. In this study, intralesional
resection had a significant recurrence rate of 19.0%
(10/52), marginal resection 5.6% (1/18), and surprisingly en bloc resection 20.0%. However, these radical
resections were probably not wide-margin resections.
The authors noted that these lesions have the potential
for local recurrence after subtotal resection [81]. From
the available literature it can be summarized that intralesional resection is recommended for nonaggressive
osteoblastomas (Enneking 2) and wide-margin resection for aggressive osteoblastomas (Enneking 3) [59].
The role of radiation therapy in recurrent or incompletely resected tumors is controversial, with the
majority of cases showing no advantage, but a minority
demonstrating a benefit [134]. Marsh et al. concluded
in their review of 197 osteoblastoma cases that “radiotherapy does not alter the course of the disease and
appears to be contraindicated” [83]. Adjunctive radiation therapy with primary surgery probably can be beneficial in the case of stage 3 osteoblastomas as well as
in recurrent tumors [18, 59]. Chemotherapy has a limited role in recurrent aggressive osteoblastomas and
there are only a few case reports in the literature [59].
Our Preference
In concordance with the Harrop et al. systematic review
[59], we prefer to observe osteomas without clinical
symptoms and located in noneloquent statodynamic
spine areas. If patient becomes symptomatic, either
radiofrequency CT-guided ablation [9] or enucleation
of the osteoma is performed (Fig. 19.9).
In nonaggressive osteoblastomas (Enneking stage
S2), a radical resection is performed if anatomically
possible, although endolesional tumor removal can be
sufficient. Growing and aggressive tumors (Enneking
253
Fig. 19.9 Osteoma capsule after high-speed drill bone removal.
Intraoperative picture
S3) should be resected as radically as possible. We
have not had a patient with an S3 osteoblastoma in
UCS region; however, we have had a good outcome
after total spondylectomy of C6 osteoblastoma in a
16-year-old girl who has survived more than 7 years
without recurrence (Fig. 19.10).
Aneurysmal Bone Cysts
Aneurymal bone cysts (ABCs) are non-neoplastic in
nature, but are expansile, composed of thin-walled
cystic areas filled with blood. They were initially
described by Jaffe and Lichtenstein in 1942 [67] and
represent approximately 15% of all primary spine
tumors but are found most frequently in flat bones
(pelvis) [3, 39]. In 10–30% of ABC cases, the spine is
involved. Commonly, they are located in the thoracic
and lumbar spine [61], but around 25% of the time
they can arise in the cervical spine [30, 77]. ABCs generally occur in first two decades of life without gender
predilection. They are usually localized to posterior
spine elements but circumferential vertebral involvement is not uncommon. They can reach enormous size
without clinical consequences. Spontaneous resolution
of ABC has been described; however, progression is
more common [30, 61, 77, 127].
254
Fig. 19.10 Plain radiographs 7 years after total spondylectomy
for osteoblastoma showing a good bone fusion without recurrence
(patient from Figs 19.6 and 19.8). (a) Lateral projection. (b) AP
19 Tu mor s
(Fig. 19.12). Selective angiography can be performed
for embolization and can reveal the common arterial
feeders to the spinal cord.
Treatment Strategy
Simple curettage with or without bone grafting, complete resection, embolization only, radiation therapy or
combination of these methods were used for treatment
of ABCs [59]. En bloc resection appears to have the
highest rate of cure; however, achieving complete excision is very difficult in ABCs, especially in the UCS.
Boriani et al. reported only 2/41 cases in which they performed en bloc resection without adjuvant radiation
[19]. Gross total endolesional resection using a highspeed drill has also been reported as effective with longterm cures [3, 19, 40, 61]. However, according to other
authors, intralesional, incomplete excision is associated
with a relatively high progression rate of up to 25%
within the first 2 years after surgery in 90% of patients
[19, 30, 61, 128]. Radiation therapy has limited primary
indications and remains an adjuvant for patients with
inoperable lesions, aggressive recurrent disease, and
medical conditions that place them at a high surgical
risk or in patients with incomplete excision. Boriani et al
reported four patients without local disease progression
after radiation alone [19]. Capanna et al. has seen three
local progressions in six irradiated patients [30]. The
successful use of preoperative, selective arterial embolization has been documented for ABCs of the pelvis
and long bones, but its role as the sole mode of therapy
in the spine is more questionable [76, 88]. Embolization
alone may be considered in patients with a recurrent
lesion after previous surgeries, or in patients who cannot
medically tolerate surgery and only if pathological fracture, spinal deformity, instability, and neurologic compromise are absent [19]. It is important to note that
fatalities have been reported with embolization procedures, particularly with cervical spine lesions [96].
Diagnosis
Clinically, ABCs can be silent with only neck pain, but
can present with vertebral collapse, deformity or signs
of neural compression. Plain radiographs can demonstrate an osteolytic lesion with “ballooning out” of the
bone cortex. This is confirmed by a typical CT appearance (Fig. 19.11) of thin-walled cavities deforming the
vertebral bony borders filled with blood. MRI demonstrates the relationship to the spinal canal contents
Our Preference
As we have only very limited experience with this type
of primary bone lesion in the UCS, we have to follow
the recommendations of Harrop et al. in their systematic review [59]. The aneurysmal bone cyst should be
removed as radically as possible to prevent further disease progression. Due to anatomic restrictions, this
goal can be difficult to achieve in the UCS, especially
19.1 Extradural UCS Tumors
255
Fig. 19.11 CT of aneurysmal bone cyst of C2 in a 7 year old girl. (a) Coronal plane reconstruction. (b) Sagittal reconstruction
showing extracompartmental extend. (c) Axial scan
if the lesion involves vertebral structures circumferentially. As these lesions often destroy stabilizing structures, reconstruction of the spine is necessary. This has
to be done with respect to the age of patient, keeping in
mind they frequently are not finished with bone growth.
Therefore, dynamically fixed (wires) autologous bone
grafts seem to be more reasonable than stable “nongrowing” constructs. Other possibilities can include
temporary metal-bone fixation with hardware removal
at a later date. Selective arterial or direct percutaneous
puncture embolization can precede the surgery to
decrease perioperative blood loss.
Adjuvant, focused radiotherapy can be added if radical resection is not achievable and/or in recurrence but
its benefit is questionable. The recurrence rate is reported
as high as 25%; however, this is probably not true recurrence but progression of residual neoplastic tissue
growth left in place after nonradical surgery. Complete
cure is reached if the resection zone is remineralized
and without CT visible tumor at 4 years follow-up.
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primary bone tumors with 10% of them affecting the
spine [38]. The cervical spine is rarely involved and in
the UCS even less frequently. Usually, they originate
from the vertebral body but gradually involve the posterior structures as well. Prognosis of GCT in spine is
unclear with a high recurrence rate whatever treatment is used.
Diagnosis
Diagnosis is often delayed as the initial symptom is
often pain with neurological deficit occurring later.
GCTs present as purely lytic lesions on plain films and
the CT is non-specific showing differing areas of osteolysis and reactive tissue with new bone formation.
MRI (Fig. 19.13), usually, does not add more diagnostic information and thus free-hand or CT-guided biopsy
is performed. The tissue histologically reveals giant
osteoclastic cells with spindle-shaped cells and regions
of fibrous tissue [87]. Because of frequent reactive
hypervascularization the bone scintigraphy is nearly
always positive.
Fig. 19.12 MRI of aneurysmal bone cyst (patient from
Fig. 19.11) and its relationship to neural structures and external
spread. (a) Axial image showing canal compromise. (b) Frontal
plane T1 image
Giant Cell Tumors (GCT )
GCTs are locally aggressive bone tumors originating
from histiofibroblastic elements. Their behavior is
unpredictable, transforming to malignant forms in
10% and occasionally having pulmonary metastases
[48, 76]. Contrary to other primary bone tumors, they
occur more frequently in females with a peak incidence in the third decade. They comprise 4–8% of
Treatment Strategy
All treatment modalities have been used to treat GCTs.
Despite some papers describing long-term success of
radiation therapy alone [33] or embolization only [62],
Fig. 19.13 MRI of recurrent giant cell tumor (Courtesy of Dr
Fricˇ, Rikshospitalet HF, Oslo, Norway)
19.1 Extradural UCS Tumors
257
the combination of radical surgery, when feasible, and
adjuvant therapy seem to be the most effective [59].
Radiotherapy can be recommended in partial resections.
Langerhans Cell Histiocytosis (LCH) – Eosinophilic Granulomas, Histiocytosis X
This lesion, often called eosinophilic granuloma is a
benign osteolytic bone process caused by reticuloendotheliosis of unknown origin. The first description
is credited to Otani and Ehrlich and to Lichtenstein
and Jaffe [78, 95]. It is more common in the first two
decades of life with a male predilection. The incidence
of LCH is approximately 1:1,500,000 inhabitants [93].
Spinal localization may be solitary or multiple and usually involves only the vertebral body. Wilner and other
authors conclude that in cases of spinal LCH the thoracic
vertebrae are involved most often (54%), followed by
the lumbar (35%), and cervical vertebrae (11%) [132].
Bertram et al. conducted a meta-analysis of their own
patients and 53 other cases of cervical LCH reported in
the literature till 2002. The UCS was involved in 54% of
adults and in 40% of children. In both groups, the vertebral body was affected in the majority of cases [12].
observation to resection and/or filling the lesion with
bone cement.
Gorham disease is an extremely rare osteolytic process that has spontaneous resolution and has been
reported in the UCS area also [76]. Osteochondroma is
derived from hamartous tissue and is extremely rare in
the UCS; however, if present and growing, can cause
neurological compression or even death [76, 106].
Fibrous dysplasia is another hamartomatous condition, which leads to weakening of trabecular bone
structure and occasionally to body collapse. It usually
resolves spontaneously; however, when causing deformity, surgical correction is indicated.
19.1.4.2 Malignant Primary Bone Tumors
Primary malignant bone tumors are more common in
older age groups than benign lesions with the peak
incidence occurring in the fourth–sixth decades of life.
The cervical spine is involved in about 20% of all spine
primary bone malignant tumors and approximately
25% of these occur in the UCS region, particularly in
the C2 vertebra. Males are affected three times more
frequently than females [20].
Diagnosis
Cervical pain, limitation of movement, and torticollis
are the most frequent symptoms. Only the osteolytic
lesion can be seen radiographically and often only
biopsy can confirm the diagnosis.
Treatment Strategy
Reported treatment of cervical LCH varies from simple
immobilization, radiotherapy, and local steroid injections, to surgical removal with anterior spine reconstruction. The outcome was good in most of the published
cases independently of the choice of treatment [12]. In
general, surgery is indicated only in cases of body collapse with deformity and/or neurological deficit.
Other Benign Tumors and Tumor-Like Lesions
Hemangiomas can rarely occur in the UCS region.
Their treatment is dependent upon the symptoms and
structural involvement. Therapy can vary from
Diagnosis
These tumors are diagnosed often late in the course of
the disease and complete vertebral involvement and/or
spreading to adjacent compartments is common. This
is caused either by slow asymptomatic growth or, alternately, by extremely fast progression. The clinical
complaints are nonspecific with neck pain and muscular spasms being most common and the tumor is often
not discovered until the adjacent soft and/or neurovascular structures are involved. The patient’s status can
dramatically worsen during rapid tumor growth with
progressive neurologic deficit, swallowing difficulties
in the case of anterior extra-compartmental extension,
or intractable pain that forces the patient to support his
head manually. Plain films often show only an osteolytic lesion (Fig. 19.14); however, if the tumor spreads
anteriorly, pharyngeal (Fig. 19.5) and even tracheal
dislocation or a neoplastic mass shadow located prevertebrally can be seen. Nonetheless, for diagnosis,
prognostic, and surgical considerations, CT and MRI
are essential. Frequently bone scintigraphy or, more
commonly, PET are used to evaluate possible multiple