Percutaneous treatment of insufficiency fractures
Principles, technique and review of literature
Douglas P. Beall & Abhijit Datir & Sharon L. D’Souza &
Logan S. D’Souza & Divya Gunda & John Morelli &
Michael Brandon Johnson & Nima Nabavizadeh
Received: 23 February 2009 /Revised: 6 May 2009 /Accepted: 14 May 2009
# ISS 2009
Abstract Insufficiency fractures of the pelvis, sacrum,
spine, and long bones are painful, debilitating, and are
common consequences of osteoporosis. Conventional treat-
ment for these fractures varies from conservative therapy to
surgery with plate and screw fixation. The former fails to
address the underlying problem of fracture and frequently
does not alleviate symptoms, while the latter is invasive and
not always possible in older populations with low bone
density and numerous co-morbidities. Osseous augmenta-
tion with polymethylmethacrylate (PMMA) has been used
for over two decades to treat fractures related to osteopo-
rosis, but has not been commonly used to treat fractures
outside of the vertebral bodies. Osseous augmentation with
PMMA is an image-guided procedure and various techni-
ques have been utilized to treat fracture in different
locations. We describe various techniques for image-
guided osseous augmentation and treatment of insufficiency
fractures with bothPMMA and allograft bone for fractures
of the pelvis including sacrum, acetabulum, pubic symphy-
sis, pubic rami ilium; appendicular skeleton including distal
radius, proximal femur, and vertebral body. We also
describe the potential risks and complications associated
with percutaneous treatment of insufficiency fractures and
techniques to avoid the pitfalls of the various procedures.
We will present the process for patient follow-up and data
regarding the pre- and postprocedure pain response in
patients undergoing treatment for pelvic insufficiency
Compression fractures occur when the combined forces
acting upon a vertebral body exceed its inherent strength.
Reduction in bone strength may be a result of benign or
malignant tumors or, more commonly, due to alteration of
internal architecture from bone mineral loss. Osteoporosis,
which may be primary (age-related) or secondary (through
steroid use, etc.), is estimated to affect approximately 1.5
million people in the United States with worldwide costs of
hip fractures alone projected to reach $131.5 billion by
Conventional, conservative treatments for osteoporotic
vertebral compression fractures focus on pain relief through
use of narcotics, analgesics, bed rest, and external bracing.
Rehabilitative mobilization and exercise are subsequently
undertaken. Despite early conservative treatment with the
above-described measures, pain relief and return to prior
mobility may take anywhere from a few weeks to several
months . For several decades, acrylic cements have been
D. P. Beall:S. L. D’Souza:L. S. D’Souza:D. Gunda:
J. Morelli:M. B. Johnson:N. Nabavizadeh
University of Oklahoma Health Science Center,
Oklahoma City, OK 73104, USA
D. P. Beall
Clinical Radiology of Oklahoma,
Edmond, OK 73083, USA
Department of Radiology, Royal National Orthopaedic Hospital,
Middlesex HA7 4LP, UK
D. P. Beall (*)
610 NW 14th Street,
Oklahoma City, OK 73103, USA
used for the augmentation of weakened or fractured osseous
The percutaneous administration of polymethylmetha-
crylate (PMMA) and allograft bone for treatment of
insufficiency fractures located in the vertebral bodies has
been shown by numerous independent researchers to be a
safe, effective means of providing pain relief [2–5]. In this
paper, we will discuss principles and techniques for image-
guided osseous augmentation for insufficiency fractures of
the axial and appendicular skeleton. We also describe the
potential risks, complications, and techniques to achieve
Percutaneous vertebroplasty was originally described in
1987 when Galibert and Deramond utilized PMMA in the
treatment of a vertebral hemangioma in the C2 vertebral
body . Since the initial report published in 1987, the use
of PMMA has become widespread, particularly with regard
to the treatment of vertebral compression fractures resulting
from osteoporosis, metastatic disease, or primary osseous
malignancies (Fig. 1). Vertebroplasty has been shown to
effectively stabilize fractured bone, decrease pain, and
subsequently increase mobility . The idea of treating a
vertebral compression fracture (VCF) by creating a void
within the bone and restoring vertebral body height was
conceived by an orthopedic surgeon, Dr. Mark Reiley, in
the early 1990s. The initial biomechanical investigations of
the inflatable balloon tamp were performed as a combined
effort by this orthopedic surgeon and a neuroradiologist
familiar with percutaneous vertebroplasty [7, 8]. This
procedure, known as kyphoplasty, utilizes an inflatable
balloon (or bone tamp) to create a cavity within the
vertebral body, which is then filled with PMMA (Fig. 2)
. More recently, continued innovation and technological
advancements have led to vertebral augmentation with
allograft bone (known as spineoplasty). This method of
treating vertebral compression fractures involves the force-
ful insertion of allograft bone into a mesh containment
device through a tube by using a plunger and mallet strikes.
Patient selection and preparation
Percutaneous vertebral augmentation procedures have gen-
erally been reserved for patients with painful osteoporotic
VCFs in whom conservative therapy has failed. It has been
postulated that the ideal patient presents within 4 months of
fracture with midline, nonradiating back pain exacerbated
by weight-bearing and reproduced by pressure upon the
involved spinous process . Brown et al. studied the
clinical benefit of vertebroplasty in symptomatic chronic
vertebral fractures more than 1 year old, and concluded that
the quality of pain relief and improvement in mobility may
be slightly lower than those fractures treated in an acute
setting . However, there have also been reports that
refute this claim, stating that vertebral augmentation is
highly efficacious regardless of fracture age or extent of
collapse [12, 13].
Vertebral augmentation is contraindicated in patients
with uncorrected coagulopathy and active infection. Tradi-
tional relative contraindications such as vertebra plana,
presence of radiculopathy, and the presence of spinal cord
impingement may be relative contraindications as more
success with relatively complex cases is being reported as
operators become more comfortable with the procedures
Fig. 1 Vertebroplastyinapatientwithspinalmetastasis(white arrow in a).
a Axial computed tomography (CT) image demonstrates a kyphoplasty
cannula that has been inserted into the T2 vertebral body (black arrow)
and an inflatable bone tamp within the vertebral body itself (black
arrowhead). b PMMA has been deposited within the vertebral body
(black arrowhead). Two cannulae are seen in the upper left portion of
the thoracic (black arrows), placed within adjacent levels
[13–15]. In general, the treating physician uses the patient
history, physical examination information, results of the
various imaging studies, and operator experience to guide
the choice of the particular therapeutic procedure.
Most interventionalists administer intravenous antibiot-
ics prior to the start of the procedure , although the
antibiotics may also be mixed into the cement and
administered directly. The patient is placed prone on the
table for thoracic and lumbar procedures and supine for
cervical interventions. The patient is then prepped, draped,
and provided with local anesthetic with stringent adherence
to sterile technique. Optimal fluoroscopic equipment plays
an important role in these procedures and both biplane and
single plane fluoroscopy have been used. In more complex
cases or with anatomy that is difficult to visualize computed
tomography (CT) may also be used. Computed tomography
may be combined with CT fluoroscopy or conventional
fluoroscopy to provide additional real-time visualization, if
The vertebral bodies of the thoracic and lumbar spine are
accessed via either a transpedicular or parapedicular
approach . Currently, the transpedicular method is most
commonly widely used as it affords the benefit of needle
placement within bone for the duration of the procedure,
thus limiting the risk of injury to adjacent structures .
Surgeons are also accustomed to this approach from their
placement of pedicle screws.
The transpedicular route may be either unipedicular or
bipedicular. A bipedicular approach may be necessary in
Fig. 2 Lateral fluoroscopic
view of the T3 vertebral body
shows an 11-gauge kyphoplasty
cannula within the vertebral
body (black arrow in a) and the
catheter that has been inserted
into the vertebral body (white
arrow in a) through the cannula.
The balloon (black arrowhead
in b) is deployed from the distal
portion of the catheter and the
PMMA is then injected into the
vertebral body (white arrow-
heads in c and d) via a bone
filler cannula (black arrow in c)
order to place the cement throughout the vertebral body.
Once the needle is placed on one side, the contralateral
pedicle is accessed and the second needle is advanced into
the vertebral body. The needles are commonly placed in the
anterior one half to anterior one third of the vertebral body
and PMMA is injected through the needle directly into the
bone (Fig. 3). This method, when compared with uni-
pedicular vertebroplasty, is slightly more invasive and may
take longer to perform because of the requirement of
placing a second needle, but this is an optimal technique to
ensure PMMA distribution throughout the vertebral body
and bilateral needle placement may be necessary in
vertebral levels that are too compressed or deformed to
allow for midline access of a unilaterally placed needle
. In the majority of cases when the vertebral body is not
significantly compressed, a unilateral approach is sufficient
for adequate cement administration. Notably, literature data
indicate that unipedicular and bipedicular vertebroplasty
demonstrate no statistically significant difference in clinical
outcome [18, 19].
A parapedicular approach is a safe and effective
alternative to the transpedicular approach when the appro-
priate anatomic landmarks are utilized . The skin entry
site is farther lateral compared with transpedicular access
and a superoinferior trajectory should be established by
drawing a line from the contralateral inferior vertebral body
corner through the ipsilateral superior vertebral body corner
(Fig. 4). The initial insertion is performed with the needle
angled 45° (relative to the patient’s back) and the needle is
placed adjacent to the vertebrae at the body/pedicle junction
using anteroposterior (AP) fluoroscopic visualization. Care
should be taken not to direct the needle too far anteriorly.
When the needle tip approaches the medial wall of the
pedicle, needle tip location within the posterior portion of
the vertebral body should be confirmed on the lateral
view. The needle tip should never transgress the medial wall
of the pedicle prior to penetrating the posterior cortical wall
of the vertebral body. This technique allows for a safe and
reproducible method of accessing the vertebral body .
Various other approaches have also been described for
needle placement in vertebroplasty depending on fracture
location and may be used especially when the pedicle is too
small or too damaged for safe needle placement . These
include a paravertebral approach (in which the needle tip
overlies the lateral pedicular cortex), a costovertebral
approach in the thoracic spine (with needle placement
between the pedicle and rib and using the rib as a safeguard
against pneumothorax), or a transoral approach in the
cervical spine .
Treatment of cervical lesions is less common than
treatment of thoracic and lumbar lesions and is achieved
via an anterolateral percutaneous approach instead of the
posterior parapedicular or transpedicular approaches used at
thoracic or lumbar levels (Fig. 5) . The anterolateral
approach is often the only viable option, given the
limitations of regional anatomy and vascular structures.
Literature reports have also identified a transoral approach
for injecting the C2 vertebral body in cases of a neoplasm
or fracture (Fig. 6) [6, 21].
Some operators prefer to perform venography prior to
the injection of PMMA. The venogram allows for visual-
ization of the vascular anatomy adjacent to the needle tip
and may predict the flow of PMMA when it is injected.
This technique requires additional time and has become less
prevalent in recent years as data have shown no statistically
significant difference in clinical outcomes .
A number of PMMA (bone cement) preparations are
commercially available with a variety of different working
times but the basic components are the same as are the
Fig. 4 The skin entry point (white arrow) for the parapedicular access
is one vertebral body width superolateral to the vertebra of interest in a
line drawn from the ipsilateral superior corner to the contralateral
inferior vertebral body corner
Fig. 3 Anteroposterior fluoroscopic image showing two cannulae
(black arrows) placed into the T10 vertebral body via the trans-
pedicular route. PMMA was injected into the vertebral body (white
arrows) via these needles and placed into the anterior one half to one
third of the vertebral body
principles for mixing the cement. A polymer powder is
mixed with a liquid monomer and opacifying agents such
as barium sulfate powder, powdered tungsten or tantalum.
Some practitioners also choose to add an antibiotic, such as
tobramycin or vancomycin, directly to the cement mixture,
although there is no compelling evidence to suggest that
this reduces the infection rate . Any additions to the
cement, however, can alter its viscosity and/or change the
working time so any modifications to the PMMA prepara-
tion must be made with this in mind [23, 24].
Several cement delivery systems are available and the
injection of PMMA should always be performed concur-
rently with direct fluoroscopic visualization. Such visuali-
zation allows for real-time visualization of the PMMA
location and care must be taken to avoid extravasation. The
cement is injected either continuously or in several short
bursts, followed by careful observation until sufficient
cement has been added to the vertebral body. The literature
shows a wide variation in the incidence of cement
extravasation outside the vertebral body during a vertebro-
plasty procedure with reported extravasation rates varying
between 26% and 97% . The injection is terminated if
the cement extravasates into the spinal canal, neural
foramina, vasculature or if there is excessive disc penetra-
tion [6, 25]. Careful monitoring of the position of the
cement is especially warranted as it enters the posterior one-
third of the vertebral body.
Following vertebral augmentation procedures a sterile
dressing is applied to the puncture site and the patient is
instructed to remain supine for approximately 1–2 h.
Patients may be monitored overnight or may also be
discharged the same day, if there are no apparent immediate
complications. Typical follow-up includes a visit at 24 h
after the procedure and then again at 2 weeks. Patients are
also instructed to call or return if they experience excessive
bleeding, fever, or pain. Vertebroplasty has been shown
repeatedly to produce significant, often immediate, post-
procedure pain reduction with subsequent improvement in
the patients’ mobility and participation in activities of daily
Kyphoplasty is a variant of vertebroplasty that also
provides stabilization of a compressed vertebral body via
the introduction of bone cement (Fig. 2). Kyphoplasty
entails a rather similar method of patient selection and
preparation, vertebral body access, and cement preparation.
The primary difference between these two procedures is
that kyphoplasty attempts to restore vertebral body height
and create an intraosseous void via an inflatable balloon
tamp placed within the vertebral body. The balloon cavities
are then filled with PMMA. It has been suggested that
kyphoplasty carries less risk of cement leaks as a result of
reduced pressure required for cement injection; however,
several researchers have shown the difference in clinical
outcomes between vertebroplasty and kyphoplasty to be
Volume and placement of PMMA
The total amount of cement that should be injected into a
vertebral body is controversial and has not yet been fully
characterized . Strength and stiffness are two factors
that can be measured via biomechanical testing, particularly
when standardizing parameters such as bone quality. In an
ex vivo study, Belkoff et al. performed bilateral injections
of bone cement into fractured osteoporotic vertebral bodies
. They found that with a total injected volume of only
2 ml they were able to restore pre-injury strength, but a total
of 4–8 ml was necessary to restore pre-injury stiffness
depending on the type of cement and the vertebral body
level. Kosmopoulos et al. (unpublished data from the 10th
Annual Symposium on Computational Methods in Ortho-
paedic Biomechanics, Texas 2002) used a two-dimensional
model for an osteopenic T10 vertebral body to look at
apparent modulus and stress changes in the trabecular
tissue. They observed various placements of the PMMA
within the vertebral body and found that PMMA placed
anteriorly and near the inferior endplate resulted in the
greatest increase in the apparent modulus of the injured
vertebral body. They concluded that their results showed
that restoration of apparent stiffness with vertebroplasty is
Fig. 5 Lateral fluoroscopic image demonstrates an 11-gauge outer
cannula placed within the C6 vertebral body (black arrow) with
PMMA (white arrow) injection within the mid to posterior portion of
the C6 vertebral body
best attained if 3–5 ml of PMMA is properly placed in the
vertebral body. It was also observed that complete
replacement of the marrow volume resulted in an apparent
stiffness above pre-injury levels.
The relief of pain may require less volume of PMMA;
Barr et al. reported that patients had 97% pain relief with 2–
3 ml injected into thoracic vertebrae and 3–5 ml injected
into lumbar vertebrae . Berlemann et al. used a set
volume of approximately 23% of vertebral body volume
(which ranged from 6 to 7 ml) and showed a significant
increase in the mechanical strength and stiffness of
osteoporotic vertebral bodies . Similarly, Heini et al.
reported an average vertebroplasty injection volume clini-
cally to be 5.9 ml (range 4–8 ml) .
The placement of the cement into the vertebral body may
be more important that the amount of cement that is
injected. Dean et al. found an asymmetrical flow pattern of
cement when using a standard unilateral vertebroplasty
technique to inject cadaveric vertebral bodies . The
strength of the injected vertebral bodies was greater than
the non-injected control group, but the magnitude of
strength increase did not correlate with the amount of
cement injected. It was suggested that a well-placed column
between the endplates could be more important for
strengthening the vertebral body than simply stiffening the
trabecular matrix with cement.
The technique of placement of PMMA for both
vertebroplasty and kyphoplasty has been debated with
regard to biomechanical stability and adequacy .
Unipedicular access has been shown to be as effective
as the bipedicular procedure in re-establishing strength
and stiffness, as well as pain relief clinically. The
indication to carry out a bipedicular approach is dependent
on the degree of compression and on the adequacy of the
flow of cement across the midline via a unipedicular
Fig. 6 a Sagittal reconstructed
CT image demonstrating a frac-
ture through the base of the
odontoid process (black arrow-
head) of the C2 vertebra. b
Lateral fluoroscopic view shows
a transoral approach to the C2
vertebral body with the 11-
gauge needle and bone filler
cannula in place (black arrow),
and PMMA (white arrowhead)
present within the C2 vertebra. c
Axial and d coronal recon-
structed CT images demonstrate
PMMA within the interstices of
the fracture (area between
arrowheads, d dens, b base of
the odontoid process)
Spineoplasty is a method of treating vertebral compression
fractures with a biological fill material (allograft bone).
Vertebral augmentation with allograft bone began with the
development of a mesh implant designed for the purpose of
interbody fusion. When used intrabody, morselized allo-
graft bone is placed within a knitted multi-strand polyester
mesh that contains the graft material .
Tools were created to allow for placement of the implant
within the vertebral body and for the filling of these
cavities. The delivery system also contains a force
dissipation plate to absorb impact from mallet strikes. The
morselized allograft bone may be mixed with demineralized
bone matrix or bone marrow mixture to change its
consistency (Fig. 7). As the allograft bone material is
biologic, no exothermic reaction or toxicity effects are
observed, as might be seen with vertebroplasty or kypho-
plasty. The polyester mesh containment device is inserted into
the vertebral body, where itisthenfilledunder pressurewith a
mallet and plunger technique. One such commercially
available product for performing spineoplasty is the Opti-
mesh® (Spineology©, St. Paul, MN, USA) system, which
works via the principles of granular mechanics—the granules
contained. This solid bone pack provides structural support by
stabilizing the vertebral body and providing an intravertebral
strut that can bear an axial loading force [33, 34].
Pelvic fractures can be extremely debilitating, particularly
as traditional therapy entails extended bed rest and
analgesics that can lead to further complications of
immobility including pneumonia and pulmonary embolism.
Sacral insufficiency fractures are a known and relatively
common cause of back pain in elderly patients .
The superior pubic ramus, though most commonly
fractured as the result of direct trauma, is susceptible to
osteoporotic insufficiency fractures, especially when asso-
ciated with sacral insufficiency fractures (as these fractures
commonly occur together). Though sacral and superior
pubic rami fractures generally heal uneventfully without
operative intervention, elderly patients often require hospi-
talization for pain management and progressive mobiliza-
tion [36, 37]. Analysis of the length of hospital stay and
home care services indicate that this population utilizes
substantial healthcare resources after sustaining such
fractures . Though the long-term results are not known,
a number of studies have shown sacroplasty to be an
effective means of pain reduction and subsequent early
mobility and at least one report of pubic ramoplasty
suggests that this is a viable alternative to conservative
therapy for the percutaneous fixation of pubic rami
fractures when other conservative therapies fail [35, 39].
Different image-guidance methods have been described in
the literature for performing a sacroplasty procedure and
can be performed under conventional fluoroscopy  or
CT guidance  or a combination of both [5, 37]. The
cannula is typically placed between the sacral foramina and
the sacroiliac joint from a vertebral bodyerior approach for
direct injection (Fig. 8). Sacroplasty can also be performed
using a modified balloon kyphoplasty technique in which a
kyphoplasty balloon is positioned and inflated at the
presumed site of cement injection (Fig. 9) . Although
balloon inflation may be useful in compacting the bone at
the periphery of the fracture to reduce the incidence of
Fig. 7 a Photograph obtained during spineoplasty procedure shows
the working cannula (black arrow) being put into place with a mallet
(white arrow) and an impactor (black arrowheads). The force
dissipation plate (white arrowheads) absorbs and distributes the force
from the mallet strikes. b Lateral fluoroscopic view obtained during
insertion of morselized allograft bone into the L1 vertebral body
shows the working cannula (white arrow) and the diverted fill tube
(white arrowhead) as well as the bone graft pack (black arrowheads)
within the vertebral body. Note that the allograft bone pack is much
less radio-opaque and less conspicuous than PMMA
cement extravasation, it is unlikely that any meaningful
degree of height restoration or fracture reduction can be
Percutaneous injection into insufficiency fractures of the
ilium and acetabulum is much less commonly performed
and, to our knowledge, no clinical data have been recorded
to date as to the efficacy of these procedures. Insufficiency
fractures of the ilium are often related to osteoporosis
combined with increased biomechanical stress (i.e. from an
ilium bone graft donor site that weakens the ilium; Fig. 10).
Insufficiency fractures of the acetabulum are typically seen
in patients with severe osteoporosis. Patients with acetab-
ular insufficiency fractures present with hip pain that may
be acute or insidious in its onset. These fractures are
typically treated conservatively with rest and analgesics, but
injection of PMMA directly into the fracture has been
reported to provide immediate relief of pain (Fig. 11) .
Fractures of the superior pubic ramus may occur in
conjunction with fractures of the sacrum and may also be
treated by injecting PMMA directly into the interstices of
the bone and across the fracture sites (Fig. 12) . An
early report has shown that this may be a viable option for
treatment of superior pubic ramus insufficiency fractures
especially in those patients who are not optimal surgical
These pelvic procedures may prove technically difficult
because of the curvilinear shape of the osseous structures,
the lack of established access pathways to the fracture sites,
and the relatively decreased amount of cancellous bone (in
comparison to the lumbar vertebral bodies). Fluoroscopic
guidance in accessing the sacrum has been well docu-
mented, but there are no standard fluoroscopically guided
Fig. 9 Fluoroscopically-guided sacroplasty in a patient with previous
cervical cancer surgery and sacral insufficiency fracture following
radiotherapy using modified balloon kyphoplasty technique. a Lateral
fluoroscopic view of the sacrum showing two overlapping 11-gauge
cannulae placed into the inferior portion of the sacrum directed
superiorly (black arrow) with two balloons (white arrow) within the
body of S1. A solitary cavity with an approximate volume of 4.5 cm3
was created on each side with maximum balloon pressure of 200 psi.
Surgical clips are seen within the pelvis from previous surgery for
cervical carcinoma. b Anteroposterior fluoroscopic view of the pelvis
shows bilateral placement of balloons within the sacrum (white
Fig. 8 CT-guided sacroplasty in a patient with sacral insufficiency
fracture . a Axial STIR MR image demonstrates an increased signal
within the sacral ala bilaterally (white arrows) with increased signal
within the left ilium (white arrowhead) from a previous iliac bone
graft donor site. b Axial prone CT image shows an 11-gauge needle in
the patient’s right sacral ala (black arrow). Polymethylmethacrylate is
seen within the sacral ala bilaterally (black arrowheads) as a result of
direct injection of the PMMA into the cancellous bone of the sacrum
approaches to the pubic rami, the acetabular ilium or the
superior pubic root . The use of fluoroscopy alone,
therefore, can be challenging, but CT guidance or perhaps
guidance with CT fluoroscopy may be effective alterna-
tives. It is also uncertain as to the implications of cement
extravasation as the pelvic fracture sites are typically
located farther away from critical neural structures than
when performing vertebral augmentation with PMMA.
Extravasation into the hip joint, around the lumbosacral
plexus or into the sacral foramina would be obvious
untoward events, but the implications of extravasation into
many of the surrounding soft tissue structures of the pelvis
remain uncertain . The risk of cement extrusion may
also be elevated given the ease with which cement fills the
fracture site and its adjacent structures without encounter-
ing significant feedback pressure from the injection system,
a problem particularly pronounced in the sacrum . Real-
time visualization with fluoroscopy or CT fluoroscopy
could allow for improved monitoring of the PMMA during
injection, but the extravasation rates for these procedures
and the implication of this extravasation are yet to be
In our institution, we have examined a total of 40
consecutive pelvic insufficiency fracture cement augmenta-
tion procedures (patient age range = 8–77 years). These
included sacral (n = 26) and nonsacral (n = 14) fracture
treatment groups. The nonsacral group included 10 ramo-
plasties, 3 ilioplasties, and 1 acetabuloplasty. We recorded
the visual analog score (VAS) for pain status at the baseline
and at 24-h postprocedure. In the sacral group, the VAS
score was reduced from a mean of 8.9 (preprocedure) to
2.0, and in the nonsacral group, from a mean of 8.0 to 2.7.
The difference in VAS score was found to be significant in
both groups (p < 0.001). No major procedure-related
complications such as infection, injury to adjacent struc-
tures or hematoma were seen.
While further data are needed on the percutaneous
treatment of insufficiency fractures of the pelvis, initial
results indicate that osseous augmentation could be a
valuable tool in the treatment of fractures of the sacrum,
superior pubic rami, parasymphyseal pubis, and the
acetabulum, particularly within the elderly population.
A natural extension of the previously described techniques
for using acrylic cement and allograft bone in the treatment
of axial skeleton fractures would be the use of these
techniques in the appendicular skeleton. This is not
unprecedented as a prospective, randomized trial of
approximately 300 patients with distal radius fractures
found that fixation with Norian SRS cement improved grip
strength, range of motion, digital motion, and use of the
Fig. 11 CT-guided acetabuloplasty in a 91-year-old male patient with
an osteoporotic insufficiency fracture of the right acetabulum. a
Coronal T1-weighted MR image shows decreased signal in the right
acetabulum (white arrow). b Axial CT image shows an 11-gauge
needle (black arrowhead) placed into the right acetabulum and
PMMA within the cancellous trabeculae (black arrow)
Fig. 10 CT-guided ilioplasty. Axial CT image obtained with the patient
in the prone position shows a cannula inserted into the right ilium (black
arrow) with PMMA injection (black arrowhead). A small amount of
PMMA is seen medial to the ilium after having extravasated from the
ilium fracture site. Not shown is the patient’s iliac bone graft donor site
located immediately adjacent to the fracture site
hand at 6–8 weeks postoperatively over closed reduction
with casting or external fixation (Fig. 13) . In this study,
the significant clinical differences seen initially were
normalized by the end of 3 months except for digital
motion, which remained significantly better in the group
treated with Norian SRS. However, at the end of 1 year, no
clinical differences were detected in these two groups. Also,
percutaneous fixation with cement was associated with
fewer infectious complications than external fixation or
with fixation with Kirschner wires. Similar findings have
been observed in smaller studies with PMMA [46, 47].
Further exploration of this therapeutic option in osteoporotic
individuals needs to be investigated, but the use of bone
cement in the appendicular skeleton appears promising.
Similarly, a fracture through the proximal femur or
femoral neck can be treated with PMMA augmentation of
the fracture site, especially in patients with difficult access
for orthopedic screw fixation due to the short length of the
available proximal fracture/bone segment. We recently
performed a cement fixation of subcapital femoral neck
Fig. 12 CT-guided pubic ramo-
plasty. a Axial CT image shows
a fracture through the superior
pubic ramus and the parasym-
physeal region of the pubis
(white arrow) along with an 11-
gauge needle (black arrowhead)
that has been inserted into the
junction between the superior
pubic ramus and the parasym-
physeal pubis. b Axial CT im-
age shows PMMA within the
interstices of the right pubic
bone (black arrow). c Postpro-
cedure coronal CT reconstructed
image demonstrates the PMMA
within the right pubic bone
filling the fracture site (black
Fig. 13 Fluoroscopically guid-
ed injection of PMMA into a
distal radial fracture. a Antero-
posterior and b lateral fluoro-
scopic images of the wrist show
PMMA within the distal radius
(white arrow) in this patient
with a nondisplaced distal radius
fracture with PMMA using an anterolateral approach in a
77-year-old woman (Fig. 14). Following the procedure, the
patient was able to walk with support from a non-
ambulatory status, and at the end of 6-month follow-up,
the patient remained ambulatory without any additional
support. To our knowledge, reports of the use of PMMA
augmentation for proximal femoral fractures have not been
published in the literature.
Procedural planning and potential complications
As with any invasive procedure, potential complications
that may be associated with the percutaneous treatment of
insufficiency fractures include risks of bleeding at the
puncture site, infection, pulmonary embolism, pneumonia,
and damage to the adjacent anatomical structures. Other
complications associated with the percutaneous injection of
PMMA into fractures include monomer toxicity, PMMA
emboli, thermal injury due to the exothermic reaction
associated with the PMMA and direct mass effect of the
PMMA on adjacent neural structures. As previously
described, proper patient selection, preprocedure evalua-
tion, adequate monitoring, and proper technique can
significantly reduce these risks.
Percutaneous osseous augmentation is contraindicated in
patients with uncorrected coagulopathy and with active
infection. Preoperatively, appropriate coagulation studies
including PT, PTT and INR should be obtained. A thorough
history and directed physical exam should be performed, and
current medications and history ofallergic reactionsshouldbe
noted. It may be appropriate to withhold certain medications
such as anticoagulants before the procedure or perhaps to
premedicate the patient with analgesics, anxiolytics or
antihistamines, depending on the individual case. Anticoagu-
lants must be temporarily discontinued prior to the procedure
as this will serve to decrease the risk of procedure-related
hemorrhage. In patients with co-morbidities and requiring
anti-coagulation,the anticoagulant may bestoppedjustbefore
the procedure and restarted shortly after the procedure.
Antiplatelet agents should be discontinued 3 days before the
procedure and low molecular weight heparin medications
should be discontinued at least 1 day prior to the procedure.
The risk of infection can similarly be reduced by
stringent adherence to sterile techniques during the proce-
dure and may be further reduced by the prophylactic use of
intravenous antibiotics prior to the procedure and/or by
including antibiotics in powdered form to the cement
mixture itself. The addition of antibiotics to the PMMA
preparation must be done with knowledge of how this
manipulation of the cement will affect the working time of
the PMMA, as the addition of antibiotic material to the
cement preparation may have a substantial affect on the
working time of the cement.
Fig. 14 Fluoroscopically guid-
ed injection of PMMA into a
subcapital femoral fracture. a
Fluoroscopic image showing a
subcapital fracture (between the
white arrows) and an anterolat-
erally placed cannula. b Injec-
tion of PMMA into the fracture
site. c Anteroposterior and d
cross-table lateral postprocedure
views of the fracture site (white
arrows in d) occupied with
The risk of damage to adjacent structures can be limited
by utilizing an appropriate technique for accessing the bone
in question, real-time visualization of the osseous structures
with high quality fluoroscopic equipment, and confirmation
of appropriate needle tip placement prior to the injection of
the substance into the bone that will provide stabilization of
the fractures. One of the most important technical precau-
tions to be fastidious about is the appropriate needle
placement by close visualization of the needle tip to ensure
the structures in the neural foramina and spinal canal are
not injured by an errant approach. A parapedicular or
transpedicular approach may be used in the vertebrae and
needle placement may be guided by fluoroscopy or CT
. Care must be taken to avoid violating the medial wall
of the pedicle (on A-P projection) prior to observing the
needle tip within the lateral portion of the vertebral body.
Other than neurological injury, the most serious compli-
cation related to the percutaneous treatment of insufficiency
fractures is a cement leak. This is particularly important in
spinal procedures as cement can leak into adjacent
vasculature, around the paraspinal soft tissues, into the
intervertebral disks, or overflow into the epidural space,
resulting in severe neural foraminal narrowing or spinal
cord compression . Most PMMA leaks are not
clinically significant, but the risk of pulmonary embolism
of cement may be as high as nearly 5% in patients
undergoing treatment for vertebral compression fractures
. The risk increases with the amount of PMMA
extravasated, and can be minimized by careful fluoroscopic
monitoring of cement filling and by using cement that is
adequately radiopaque and of appropriate viscosity .
Some authors suggest the risk of cement extravasation in
vertebroplasty is increased when cement is injected under
higher pressures and techniques such as kyphoplasty may
provide a viable alternative as the flow of cement into the
cavity created during kyphoplasty may provide a pathway
of least resistance for the cement . Cavity creation is
also seen in spineoplasty, but this cavity allows for the
filling of the corticocancellous allograft bone and the
primary responsibility for extravasation control lies with
the mesh implant that the allograft is injected into, rather
than with the cavity itself.
The risk of cement extravasation has not been adequate-
ly characterized in fracture treatment outside of the
vertebral bodies, but there have been no serious complica-
tions associated with sacroplasty and the largest study of
sacroplasty has documented no permanent complications
associated with the procedure . The technical consid-
erations of cement extravasation are different in the pelvis
and appendicular skeleton compared with the spine and
further research will be required to accurately characterize
the frequency of extravasation-related injury and the most
common injuries associated with this type of extravasation.
An adjacent level fracture is also an adverse event that
may be related to vertebral augmentation procedures. This
is controversial, as various studies have shown the rate of
adjacent level fractures with vertebroplasty to be less than
that of kyphoplasty  or greater with kyphoplasty than
the native rate of adjacent level fractures in patients who
have not undergone vertebral augmentation . Addition-
al data with alternate fill material (i.e., allograft bone,
ceramic materials, resin polymer glues, etc.) will likely be
available soon and may provide adequate vertebral body
stabilization with a lower rate of adjacent level fractures.
Although rare, toxicities of PMMA have been described
in animal models and high levels of PMMA have been
shown to decrease pulmonary function and systemic blood
pressure . Acute reversible bronchospasm during a
vertebroplasty has also been reported in a technologist who
had a history of asthmatic attacks, but had never before
been exposed to PMMA .
The risk of thermal injury due to the exothermic reaction
of PMMA polymerization is another possible source of
injury. This is a consideration especially when using
PMMA preparations that have high exothermic reaction
temperatures. These risks vary according to the type of
PMMA used and may be avoided altogether by using
allograft bone or an alternate fill material without signifi-
cant exothermic reaction characteristics.
Complications related to vertebral augmentation can further
be reduced with appropriate postprocedure activities and
follow-up. At the conclusion of the procedure, the patient is
instructed to remain recumbent for 1–2 h. During this time,
the patient is monitored and a neurological examination is
performed. Once ambulatory, patients are generally dis-
charged on the same or the following day and are instructed
to return for follow-up at 24 h and 1 week postprocedure.
This follow-up protocol allows for early detection of
potential complications and facilitates early recognition
and treatment of any complications that may arise.
Visual Analog Scale scores are usually obtained at
baseline (preprocedure), at 24 h, 3 months and at the end
of 6 months. Patient-rated ADL (activities of daily living)
scores may also be obtained.
Summary and conclusion
Osteoporosis is common and osteoporotic fractures are very
common and are generally under-recognized and under-
treated. Conservative medical treatments are aimed at
decreasing pain and generally involve several weeks to
even months of immobilization. This limited mobility may,
in itself, be detrimental and may be associated with
increased morbidity and mortality. Traditional surgical
treatments are often not an option given the weakened
state of the involved bone and the fact that osteoporotic
patients are very often elderly and may be poor surgical
candidates because of other co-morbidities. Percutaneous
administration of acrylic cements and other fill materials
will likely continue to be a viable treatment option to
address pain and restore function. Extensive research
regarding the percutaneous treatment of vertebral compres-
sion fractures has shown these methods to be safe and
effective at alleviating pain, stabilizing the bone, and
decreasing the debilitation of the patient. Additional
techniques involving the percutaneous stabilization of
osteoporotic fractures outside of the spine have shown
excellent potential to provide pain relief and decrease
patient debilitation. Additional research, new technique
descriptions and clinical trials will be necessary before
these techniques become as well established as the
techniques for percutaneous vertebral augmentation, but
the early applications in the appendicular skeleton and the
nonvertebral axial skeleton appear promising.
Edmond, OK, USA, and performed by the personnel of Clinical
Radiology of Oklahoma.
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