Open Journal of Radiology, 2013, 3, 152-158
http://dx.doi.org/10.4236/ojrad.2013.33025 Published Online September 2013 (http://www.scirp.org/journal/ojrad)
Image Findings Following Vertebroplasty in Os teoporotic
Vertebral Compression Fractures: Bone Healing and
Sagittal Alignment
Hirotaka Ikeda1*, Misako Nishio1, Shin Matsuoka1, Brandon D. Lohman1,
Shoichiro Matsushita1, Yukihisa Ogawa1, Shingo Hamaguchi1, Yasuo Nakajima1,
Atsushi Kojima2, Yoshiaki Torii2, Yutaka Sasao2
1Department of Radiology, St. Marianna University School of Medicine, Kawasaki, Japan
2Department of Orthopedic Surgery, St. Marianna University School of Medicine, Kawasaki, Japan
Received June 11, 2013; revised July 11, 2013; accepted July 18, 2013
Copyright © 2013 Hirotaka Ikeda et al. This is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ABSTRACT
Purpose: To clarify the effect of percutaneous vertebroplasty for vertebral compression fracture by assessing the changes
of radiographic and CT image findings. Materials and Methods: A retrospective radiological analysis comprising 101
vertebrae of 48 patients who underwent percutaneous vertebroplasty for painful osteoporotic vertebral compression
fracture was conducted. Whole spine radiographs and CT images were compared in patients preoperatively and 6
months postoperativey. Sagittal Cobb angles in three regions, sagittal vertical axis, and pelvic tilt were measured using
whole spine lateral radiographs. CT findings due to the vertebral compression fracture, its healing process, and compli-
cations were evaluated. Results: On radiographs, sagittal alignment had an average gain of no more than 2.5˚ in each
region. Sagittal vertical axis and pelvic tilt did not show significant change. Out of 68 vertebrae that demonstrated cor-
tical disruption on preoperative CT, 37 (54%) demonstrated fusion of disrupted cortex on postoperative CT. Conclusion:
No significant difference was observed between preoperative and postoperative spinal sagittal alignment on radiographs.
However, CT did reveal healing process through fusion of disrupted cortex, intervertebral bridging, and increased den-
sity of cancellous bone. It is suggested that cement in the space of fracture may play a role in both mechanical stability
and bone union.
Keywords: Vertebroplasty; Polymethylmetacrylate; CT; Sagittal Alignment; Bone Union
1. Introduction
Osteoporotic vertebral compression fracture (VCF) is a
common cause of back pain in the elderly population and
is known to be associated with neurologic compromise,
permanent disability and spinal deformity [1]. In addition
to these commonly associated ailments, VCF may also
progress into spinal kyphosis which in fact, may alter
spinal biomechanics consequently affecting spinal erec-
tor muscles and therefore causing severe fatigue and pain.
It may also involve various bodily systems and cause
respiratory dysfunction, gastro-esophageal reflux disease,
loss of appetite and decrease both lung capacity and ab-
dominal space [2].
To this end, percutaneous vertebroplasty (PVP) ap-
pears to be the treatment of choice where conservative
management has failed [3,4]. PVP is a minimally inva-
sive procedure that effectively addresses severe back
pain associated with VCF and helps prevent kyphosis
progression. Theoretically, restoring the overall spinal
sagittal alignments in VCF patients is believed to hold
obvious benefits. However, although several authors re-
ported that PVP effectively reduced local kyphosis in
fractured vertebrae [5,6], few have yet reported PVP’s
role in improving overall sagittal alignment. Additionally,
multi-detector computed tomography (MDCT) effectively
evaluates any morphological changes and overall fracture
healing process [7,8].
To our knowledge, no report has yet analyzed post-
PVP osteoporotic VCF healing process from CT imaging
and the purpose of this present study was to assess over-
all spinal alignment changes as well as examine VCF
bony healing process based on pre and post-PVP MDCT.
*Corresponding author.
C
opyright © 2013 SciRes. OJRad

H. IKEDA ET AL. 153
2. Materials and Methods
2.1. Patients
Over a three-year period (February 2009 to March 2011)
our institution retrospectively assessed 162 post-PVP cases
for osteoporotic VCF. The inclusion criteria were pre-
and 6 months post-PVP interventions with both spine CT
in the supine position and whole spine lateral radiographs
in the standing position. Exclusion criteria consisted of
additional PVP treatment or surgery within 6 months after
PVP (n = 4), as well as imaging artifacts (n = 1). Out of
the 162 patients who underwent PVP, 53 met the inclu-
sion criteria, 5 were excluded, and 48 with a total number
of 101 vertebral compression fractures were enrolled to
this study. Baseline characteristics of the patients are
shown in Table 1. Our institutional review board ap-
proved this study and waived the need for informed con-
sent.
2.2. PVP Procedures
The PVP procedures were performed by 4 interventional
radiologists (K.T., S.H., Y.O., M.N.) with at least 4 years
of experience, using a single C-arm fluoroscopy and
consisted of transpedicular bone cement injection under
the isocenter puncture method (ISOP) [9]. In the fluo-
roscopy suite patients underwent sedation with intrave-
nous administration of 25 mg hydroxyzine hydrochloride
and 15 mg pentazocine in which subsequently a 23-
gauge needle with 10 mL 1% Lidocaine was inserted in
the vicinity of the targeted vertebra. A 13- or 15-gauge
bone biopsy needle was placed transpedicularly in the
anterior two thirds of the fractured vertebral body. Bar-
ium-opacified polymethylmethacrylate (PMMA) bone
cement was injected under continuous fluoroscopic im-
aging. The injection was terminated when the cement
spread to the posterior quarter of the vertebra or cement
leakage occurred. The needle was removed and the pa-
tients rested in the supine position for at least 2 hours.
Table 1. Characteristics of patients.
Characteristics Value
Age (year old) 76 ± 6
Sex (Female/Male) 35/13
Height (cm) 145.6 ± 19.6
Body weight (kg) 49.0 ± 7.9
Body Mass Index (kg/cm2) 22.2 ± 4.1
History of Parkinson’s disease
(number of cases) 4
History of cerebral vascular accident
(number of cases) 0
History of rheumatoid arthritis
(number of cases) 0
steroid use more than 5mg/day
(number of cases) 4
Indications for PVP were as follows: 1) older than 60
years of age; 2) continuous pain lasting for a period of
over 6 weeks despite conservative therapy with bed rest,
physical therapy, and analgesics; 3) bone edema or pseu-
doarthrosis at fractured vertebrae on CT or MRI; and 4)
VCF at T5 or lower. The exclusion criteria were as fol-
lows: 1) infection; 2) coagulopathy; 3) severe cardio-
pulmonary comorbidity; 4) suspected underlying malig-
nancy; 5) destroyed posterior wall with neurological
symptoms; and 6) severe biconcave type fracture formed
consent.
2.3. Imaging Analysis
2.3.1. Whole Spine Radiographs & Spinal CT
Lateral whole spine radiographs in the standing position
were obtained both pre- and six months post-PVP pro-
cedures. Two diagnostic radiologists (H.I. and S.M.) then
performed imaging analysis using imaging viewer (Yo-
kogawa Electronic Corporation, Japan) and compared sa-
gittal tilt angle of 3 separate regions following the Cobb
method; (thoracic kyphosis (T5-T12), lumbar lordosis
(T12-S1) and thoracolumbar kyphosis (T10-L2)) as well
as sagittal vertical axis (SVA) and pelvic tilt (PT) [10,11]
(Figure 1).
All patients were scanned with a 64-MDCT scanner
(Aquilion 64, Toshiba Medical Solutions). The scanning
parameters were as follows: 120 kVp; a 0.5 mm colli-
mation; a 0.75-second rotation time; a pitch of 0.64;
3-mm-thick reconstructions; and 3-mm reconstruction
increments with a bone reconstruction algorithm (FC31).
Sagittal and coronal images were reconstructed and
compared from the data sets obtained pre- and post-PVP
with MDCT using a ZIO workstation (ZIOSOFT, Japan).
2.3.2. Semi quantitative Meth od
Vertebral fractures were assessed following the semi-
quantitative method which was originally established by
Genant et al. [12] and consists of a visual evaluation of
collapsed vertebrae. This method is documented to have
higher inter- and intra-observer agreement when com-
pared to the more widely utilized quantitative method
[12]. Grade I represents deformity with vertebral height
reduction ranging from 20% to 25%, Grade II reduction
from 25% to 40% and Grade III reduction >40%. The
semiquantitative method can also grade vertebral fracture
from MDCT remodeled sagittal views and can be as use-
ful as a traditional lateral radiographs [13,14].
2.3.3. CT Ima gi ng
CT imaging of the pre- and post-PVP procedures can
clearly delineate the healing processes involved within
and around the fracture zone of the vertebral body. For
this purpose we divided the findings according to: 1)
findings from fracture, 2) findings from healing process

H. IKEDA ET AL. 154
Figure 1. 50-year-old healthy woman with whole spine radiograph that shows the ways of measurements. (a) Thoracolumbar
(T10-L2) and lumbar (T12-S1) lordotic angle measurement lines using Cobb method are shown. (b) Thoracic kyphotic angle
(T5-T12) measurement lines using Cobb method are shown. (c) Sagittal balance that is the distance from posterior edge of
sacral endplate to C7 vertical axis is measured. (d) Pelvic tilt angle is defined as the angle between a vertical line and a line
connecting the midpoint of bilateral femor al he ads and the midpoint of sacr al endplate .
and 3) complications.
1. Findings from fracture are characterized with 1) the
minimal spinal canal diameter at the fractured level on
sagittal reconstructed CT data, inspecting how much of
the spur or PMMA protruded into spinal canal (Figure 2);
2) Cortical bone disruption was observed in the supe-
rior/inferior endplate, anterior, posterior and/or lateral
wall of vertebra. (Figure 3(a)).
2. Findings from healing process describe 1) the fu-
sion of disrupted cortex that can be detected on follow-up
CT and compared with the pre-PVP CT images (Figure
3(b)); 2) Intervertebral bony bridging structures attach
the PVP-treated fractured vertebra with the immediately
adjacent superior or inferior vertebra with the help of
elongated and fused spurs often found in the anterior
surface of the vertebrae (Figure 4); 3) Increased cancel-
lous bone density may be representative of cancellous
bone stiffness resulting from intravertebral ossification
from the union of a fractured vertebral body (Figure 5).
Figure 2. Minimal spinal diameters of sagittal reconstructed
images of both preoperative (a) and 6 months postopera tive
(b) CT were measured.
3. Finally, Complications were generally associated
with cement leakage from the treated vertebral body (Fig-
ure 3(b)) and also additional vertebral fractures that ap-
pear on follow-up CT imaging.
2.4. Statistical Analysis Figure 3. 78-year-old woman with osteoporotic vertebral
compression fractures who underwent percutaneous verte-
broplasty at T10-T12. (a) Sagittal reconstruction of preop-
erative spine CT shows disrupted cortex at the fractured
vertebra (circle). (b) Fusion of disrupted cortex was seen at
the same vertebra on the CT taken 6 months after PVP
(dashed circle). Cement leakage from the treated vertebra
was also seen in the intervertebral space (arrow).
The results of imaging analysis of the whole spine radio-
graph are provided as mean ± standard deviation of
measured angles and length. The results of CT image
analysis are provided as the percentage of the vertebrae
where each finding was obtained. Statistical analysis was
performed using commercially available software (JMP,

H. IKEDA ET AL. 155
Figure 4. 80-year-old woman with osteoporotic vertebral
compression fractures who underwent percutaneous verte-
broplasty at T12-L1. (b) Sagittal reconstructed CT image 6
months postoperatively shows anterior bony bridging con-
necting the T12 vertebrae on which PVP was performed
and its adjacent T11 vertebra (arrow). (a) Bony bridging
was not seen on the CT taken before the PVP procedure.
Figure 5. 82-year-old woman with osteoporotic vertebral
compression fractures who underwent percutaneous verte-
broplasty at L3. (b) Increased cancellous bone density
(dashed circles) seen at the structure surrounding the in-
jected PMMA cement on the reconstructed axial image of
spine CT taken 6 months postoperatively, compared to CT
taken preoperatively (a).
version 8.0.2, SAS Institute). The t-test was applied to
determine whether the results of the measurements on
whole spine radiographs and the minimal spinal diameter
on CT were significantly different pre- and post-PVP. A
p value of less than 0.01 was considered to indicate sta-
tistical significance.
3. Results
The mean age of the patients was 76 ± 6 years (35
women and 13 men). The mean follow-up period was 6.2
± 0.7 months (5 - 7 months). The treated levels were dis-
tributed from T7 to L5: 2 in T7, 1 in T8, 2 in T9, 4 in
T10, 6 in T11, 21 in T12, 22 in L1, 22 in L2, 11 in L3, 7
in L4, and 3 in L5.
On whole spine radiographs, we found no significant
difference (p < 0.01) between thoracic, thoracolumbar
kyphosis, lumbar lordosis, SVA, and PT angle in pre-
and post-PVP imaging investigations (Table 2).
Out of a total of 101 VCF in 48 patients, 97 vertebrae
Table 2. The result of measurements using lateral whole
spine radiograph.
Measurements PreoperationPostoperation Δpost - prep value
Thoracic (T5-12)
kyphotic angle 36.4 ± 17.437.4 ± 18.8 0.9 ± 8.30.611
Thoracolumbar
(T10-L2) kyphotic
angle
34.5 ± 16.736.9 ± 17.3 2.5 ± 7.10.013
Lumbar (T12-S1)
kyphotic angle −23.6 ± 18.6−24.4 ± 19.0 −0.8 ± 10.00.695
Sagittal balance
(mm) 78.7 ± 47.282.5 ± 52.9 3.8 ± 31.90.383
Pelvic tilt angle33.8 ± 11.034.2 ± 11.0 0.4 ± 5.40.473
Positive value of Cobb angle indicate kyphosis, negative values of Cobb
angle indicate lordosis. None of the measurements showed statistically
significant difference between pre- and 6 months post-PVP.
retained the same type of deformity while 94 vertebrae
demonstrated identical degree of severity on both pre-
and post-PVP CT analysis.
Following a semi-quantitative method inspection, we
did not identify any significant differences in morphol-
ogy and severity of fracture on sagittal reconstructed
images of CT (Figure 6).
The mean minimum spinal diameter was 11.2 mm ±
2.4 on pre-PVP CT and 10.9 mm ± 2.6 on post-PVP CT,
which did not show any significant difference (p = 0.03).
The mean preoperative and postoperative loss of spinal
canal diameter was 0.3 mm ± 1.4 (Table 3).
Out of 101 vertebrae, 68 vertebrae (68%) showed cor-
tical disruption on Pre-PVP CT in which 37 vertebrae
(54%) demonstrated fusion of disrupted cortex on Post-
PVP CT.
Furthermore, of the 101 vertebrae, 26 (26%) were
identified with increased cancellous bone density and 11
(11%) demonstrated intervertebral bridging. However 47
vertebrae (47%) displayed PMMA leakage while new
fractures were identified in 18 (38%) of 48 cases (Table
4).
4. Discussion
To our knowledge, this is the first report describing post-
PVP healing process of vertebral compression fractures
with CT imaging as well as its accompanying spinal sta-
bilization.
As a matter of fact, Post-PVP CT imaging demon-
strated clear healing process findings containing cortical
fusion, intervertebral bridging formation and increased
cancellous bone density. However, no significant differ-
ences between morphological changes, severity of verte-
bral fracture could be obtained from pre- and post-PVP
CT imaging analysis. From these evaluations, PVP
proved to provide effective internal fixation to the frac-
tured vertebrae and maintain spinal alignment stabiliza-
tion hence resulting in pain reduction. Albeit the lack of

H. IKEDA ET AL. 156
0
5
10
15
20
25
30
wedge
mild
wedge
mo dera te
wedge
severe
biconcave
mild
biconcave
moderate
biconcave
severe
crush
mild
crush
moderate
crush
severe
number of vertebrae
p
reoperation
p
ostoperation
Figure 6. Distribution patterns of morphology and severity of vertebral compression fracture regarding the Semiquantitative
method.
Table 3. CT findings of vertebral compression fracture and
its number of vertebrae (%).
Preoperation Postoperation
CT findings Positive Better Worse No change
Cortical
disruption 68 (67.3) 37 (36.6) 18 (17.8) 46 (45.5)
Hyperdense
cancellous bone 68 (67.3) 26 (25.7) 18 (17.8) 59 (58.4)
Minimal spinal
diameter (mm) 11.1 ± 2.4 10.9 ± 2.6
Table 4. Postoperative CT findings and its number of ver-
tebrae (%).
Fingings of healing process
Fusion of disrupted cortex 37 (36.6)
Intervertebral bridging 11 (10.9)
Increased density of cancellous bone26 (25.7)
Findings of complications
Cement leakage 47 (46.5)
New fracture 18 (37.5)
significant improvement in Cobb angle [thoracic
(T5-T12), thoracolumbar (T10-L2) and lumbar (T12-S1)],
sagittal vertebral axis (spinal balance parameter) and
pelvic tilt (spinopelvic parameter) (Table 2); it is note-
worthy to mention that among all CT studies, cortical
fusion was most commonly observed and represented
complete union of fractured vertebrae after PVP (Figure
3(b)).
The PVP cementing action creates an intervertebral
bridging consisting of elongated spur formations that
appear to enhance the biomechanical stability of the ver-
tebral unit including not only the treated vertebra in
question but also the adjacent vertebrae (Figure 4(b)).
Furthermore, CT studies of PVP-treated vertebrae dis-
played marked increased density within cancellous bone,
most likely resulting from bony tissue reaction to PMMA
which thereby, precipitate into a callus formation that
would lead to the vertebral fracture fixation (Figure 5).
In concordance with Braunstein et al. whom reported
microscopic callus formations within woven bone sur-
rounding the injected PMMA in human osteoporotic
VCF [15], we likewise detected post-PVP hyperdensities
in cancellous bones in 26 vertebrae representing fracture
healing. However, hyperdense cancellous formations
were also detected in 68 pre-PVP vertebrae and may re-
present normal healing process occurring within the zones
of fracture. Although it has not been elucidated yet whe-
ther PMMA actually fuses with human vertebrae [15-18],
it appears to play a role as an inducing agent in the nor-
mal process of fracture healing. Studies comparing the
histomorphometry and CT findings of PMMA injected
vertebrae with non-PMMA injected vertebrae are war-
ranted in order to clarify and confirm with certainty this
bony reaction.
In addition, we evaluated the minimal spinal diameter
within the sagittal spinal canal in order to assess the risk
of neural complication from PVP. Indeed, intra-vertebral
cement injection during PVP procedure has been re-
ported to cause spinal canal narrowing, thereof forming
protruding bony fragments within the spinal canal which
potentially may increase the risk of neurological deficits
[19,20]. The authors of this study did not identify any
significant changes in minimal spinal diameter on both
pre- and post-PVP and assumed that the spinal canal
narrowing held a low risk of neural complications (Fig-
ure 2).
In comparison to previous reports, contrarily to our
expectations, this study exhibited, a noticeably high
number of newly detected vertebral fractures upon fol-
low-up examinations. We attributed this prevalence to
the fact that the newly diagnosed VCFs were detected
with CT imaging in contradistinction with recent reports
which identified post-PVP fractures utilizing radiographic

H. IKEDA ET AL. 157
images [21,22]. CT imaging identifies with higher sensi-
tivity and more accuracy the occurrence of newly devel-
oped VCF that would not be detected otherwise [14].
PVP is recognized to improve local kyphosis [5,6] how-
ever our study indicated no significant improvement in
overall kyphosis or sagittal balance. Actually, it appears
that the results of this present study rather demonstrated
that progression of kyphosis may have possibly increased
slightly during the follow-up period, presumably as ky-
phosis, when left untreated, would follow its natural
course and aggravate.
Admittedly, kyphosis correction improves quality of
life and SVA is a critical element known to improving
health-related quality of life [23]. However our data did
not show any improvement of SVA values. It has been
reported that local kyphotic angle tend to worsen within
2 years after deformity reduction [24,25]. It is therefore
our contention that PVP may hold value only in correct-
ing local kyphosis by decreasing fracture mobility but
may not decidedly contribute to the overall sagittal align-
ment and PVP’s role may limit itself to the fixation of
vertebral body fractures.
After examining pre-and post-PVP stability of overall
sagittal alignment and vertebral fracture union our results
indicated that mechanical stabilization of the spine by
internal fixation of fractured vertebrae appeared to be the
dominant factor in pain reduction in post-PVP proce-
dures.
Detailed analysis of the fracture healing process is of-
ten difficult to detect on MRI or spine radiographs, and
more so during the early stage of the bone healing proc-
ess, at a time when a definite evaluation of the imple-
mented PVP is crucial to determine subsequent manage-
ment procedures. To this effect, follow-up CT imaging
can be a viable alternative although the risk of radiation
associated with CT deserves judicious planning and cau-
tion.
Given the retrospective nature of this study, we ac-
knowledge that there are a number of inherent limitations,
including the small sample size, lack of a control group
as well as pathological investigation of bone healing. We
initially aimed to define which imaging data pertained
most relevantly to pre- and post-PVP in order to set the
ground for future studies that would correlate such inves-
tigation with clinical outcomes. In fact, a longer fol-
low-up period and a clinical assessment addressing the
degree of pain reduction and quality of life improvement
could provide valuable insight regarding PVP treatment
during VCF. A prospective analysis confirming these
findings in future studies is warranted
5. Conclusion
In conclusion, percutaneous vertebroplasty in case of
vertebral compression fracture does not significantly im-
prove overall spinal sagittal alignment as previously re-
ported with local kyphotic angle in radiographic imag-
ing. However, CT investigations determined the presence
of cortical fusion, inter-vertebral bridging formation and
increased cancellous bone density. PVP appears to be in-
volved in both mechanical stability and bone union of
vertebral compression fractures.
6. Acknowledgements
The authors are grateful to Dr. Kenji Takizawa who su-
pervised this project.
REFERENCES
[1] J. J. Verlaan, F. C. Oner and W. J. Dhert, “Anterior Spi-
nal Column Augmentation with Injectable Bone Ce-
ments,” Biomaterials, Vol. 27, No. 3, 2006, pp. 290-301.
doi:10.1016/j.biomaterials.2005.07.028
[2] S. R. Garfin, H. A. Yuan and M. A. Reiley, “New Tech-
nologies in Spine: Kyphoplasty and Vertebroplasty for
the Treatment of Painful Osteoporotic Compression Frac-
tures,” Spine (Phila Pa 1976), Vol. 26, No. 14, 2001, pp.
1511-1515.
[3] M. O. Baerlocher, P. L. Munk, D. M. Liu, G. Tomlinson,
M. Badii, et al. “Clinical Utility of Vertebroplasty: Need
for Better Evidence,” Radiology, Vol. 255, No. 3, 2010,
pp. 669-674. doi:10.1148/radiol.10092107
[4] W. T. Ploeg, A. G. Veldhuizen, B. The and M. S. Sietsma
“Percutaneous Vertebroplasty as a Treatment for Osteo-
porotic Vertebral Compression Fractures: A Systematic
Review,” European Spine Journal, Vol. 15, No. 12, 2006,
pp. 1749-1758. doi:10.1007/s00586-006-0159-z
[5] M. Krauss, H. Hirschfelder, B. Tomandl, G. Lichti and I.
Bar, “Kyphosis Reduction and the Rate of Cement Leaks
after Vertebroplasty of Intravertebral Clefts,” European
Radiology, Vol. 16, No. 5, 2006, pp. 1015-1021.
doi:10.1007/s00330-005-0056-6
[6] M. B. Pitton, U. Koch, P. Dreesand and C. Duber, “Mid-
term Follow-Up of Vertebral Geometry and Remodeling
of the Vertebral Bidisk Unit (VDU) after Percutaneous
Vertebroplasty of Osteoporotic Vertebral Fractures,” Car-
dioVascular and Interventional Radiology, Vol. 32, No. 5,
2009, pp. 1004-1010. doi:10.1007/s00270-009-9521-y
[7] C. R. Krestan, H. Noske, V. Vasilevska, M. Weber, G.
Schueller, et al., “MDCT versus Digital Radiography in
the Evaluation of Bone Healing in Orthopedic Patients,”
American Journal of Roentgenology, Vol. 186, No. 6,
2006, pp. 1754-1760. doi:10.2214/AJR.05.0478
[8] J. E. Kuhlman, E. K. Fishman, D. Magid, W. W. Scott Jr.,
A. F. Brooker and S. S. Siegelman, “Fracture Nonunion:
CT Assessment with Multiplanar Reconstruction,” Radi-
ology, Vol. 167, No. 2, 1988, pp. 483-488.
[9] S. Sakaino, K. Takizawa, M. Yoshimatsu, Y. Ogawa, K.
Yagihashi and Y. Nakajima, “Percutaneous Vertebro-
plasty Performed by the Isocenter Puncture Method,” Ra-
diation Medicine, Vol. 26, No. 2, 2008, pp. 70-75.
doi:10.1007/s11604-007-0197-4

H. IKEDA ET AL. 158
[10] M. F. O’Brien, T. R. Kuklo, K. M. Blanke, et al., “Ra-
diographic Measurement Manual,” Spinal Deformity
Study Group (SDSG), Medtronic SofamorDanek, 2004.
[11] P. Roussouly and C. Nnadi, “Sagittal Plane Deformity:
An Overview of Interpretation and Management,” Euro-
pean Spine Journal, Vol. 19, No. 11, 2010, pp. 1824-
1836. doi:10.1007/s00586-010-1476-9
[12] H. K. Genant, C. Y. Wu, C. van Kuijk and M. C. Nevitt,
“Vertebral Fracture Assessment Using a Semiquantitative
Technique,” Journal of Bone and Mineral Research, Vol.
8, No. 9, 1993, pp. 1137-1148.
doi:10.1002/jbmr.5650080915
[13] D. Muller, J. S. Bauer, M. Zeile, E. J. Rummeny and T.
M. Link, “Significance of Sagittal Reformations in Rou-
tine Thoracic and Abdominal Multislice CT Studies for
Detecting Osteoporotic Fractures and Other Spine Ab-
normalities,” European Radiology, Vol. 18, No. 8, 2008,
pp. 1696-1702. doi:10.1007/s00330-008-0920-2
[14] J. S. Bauer, D. Muller, A. Ambekar, M. Dobritz, M. Ma-
tsuura, et al., “Detection of Osteoporotic Vertebral Frac-
tures Using Multidetector CT,” Osteoporosis Interna-
tional, Vol. 17, No. 4, 2006, pp. 608-615.
doi:10.1007/s00198-005-0023-8
[15] V. Braunstein, C. M. Sprecher, A. Gisep, L. Benneker, K.
Yen, et al., “Long-Term Reaction to Bone Cement in Os-
teoporotic Bone: New Bone Formation in Vertebral Bod-
ies after Vertebroplasty,” Journal of Anatomy, Vol. 212,
No. 5, 2008, pp. 697-701.
doi:10.1111/j.1469-7580.2008.00883.x
[16] M. Libicher, J. Hillmeier, U. Liegibel, U. Sommer, W.
Pyerin, et al., “Osseous Integration of Calcium Phosphate
in Osteoporotic Vertebral Fractures after Kyphoplasty:
Initial Results from a Clinical and Experimental Pilot
Study,” Osteoporosis International, Vol. 17, No. 8, 2006,
pp. 1208-1215. doi:10.1007/s00198-006-0128-8
[17] I. A. Grafe, M. Baier, G. Noldge, C. Weiss, K. Da Fon-
seca, et al., “Calcium-Phosphate and Polymethylmetha-
crylate Cement in Long-Term Outcome after Kyphoplasty
of Painful Osteoporotic Vertebral Fractures,” Spine (Phila
Pa 1976) , Vol. 33, No. 11, 2008, pp. 1284-1290.
[18] E. M. Ooms, J. G. Wolke, M. T. van de Heuvel, B.
Jeschke and J. A. Jansen, “Histological Evaluation of the
Bone Response to Calcium Phosphate Cement Implanted
in Cortical Bone,” Biomaterials, Vol. 24, No. 6, 2003, pp.
989-1000. doi:10.1016/S0142-9612(02)00438-6
[19] M. Hoshino, H. Nakamura, H. Terai, T. Tsujio, M. Na-
beta, et al., “Factors Affecting Neurological Deficits and
Intractable Back Pain in Patients with Insufficient Bone
Union Following Osteoporotic Vertebral Fracture,” Euro-
pean Spine Journal, Vol. 18, No. 9, 2009, pp. 1279-1286.
doi:10.1007/s00586-009-1041-6
[20] T. Hashimoto, K. Kaneda and K. Abumi, “Relationship
between Traumatic Spinal Canal Stenosis and Neurologic
Deficits in Thoracolumbar Burst Fractures,” Spine (Phila
Pa 1976), Vol. 13, No. 11, 1988, pp. 1268-1272.
[21] M. J. Nieuwenhuijse, H. Putter, A. R. van Erkel and P. D.
Dijkstra, “New Vertebral Fractures after Percutaneous
Vertebroplasty for Painful Osteoporotic Vertebral Com-
pression Fractures: A Clustered Analysis and the Rele-
vance of Intradiskal Cement Leakage,” Radiology, Vol.
266, No. 3, 2013, pp. 862-870.
[22] N. Tanigawa, S. Kariya, A. Komemushi, M. Nakatani, R.
Yagi, et al., “Percutaneous Vertebroplasty for Osteo-
porotic Compression Fractures: Long-Term Evaluation of
the Technical and Clinical Outcomes,” American Journal
of Roentgenology, Vol. 196, No. 6, 2011, pp. 1415-1418.
doi:10.2214/AJR.10.5586
[23] V. Lafage, F. Schwab, A. Patel, N. Hawkinson and J. P.
Farcy, “Pelvic Tilt and Truncal Inclination: Two Key Ra-
diographic Parameters in the Setting of Adults with Spi-
nal Deformity,” Spine (Phila Pa 1976), Vol. 34, No. 17,
2009, pp. E599-606.
[24] Y. Sasao, A. Kojima, M. Kaneko, A. Fujii, Y. Torii, et al.,
“Short-Term Outcome of Percutaneous Vertebroplasty
(PVP),” Journal of St. Marianna University, Vol. 1, 2010,
pp. 83-91.
[25] D. H. Heo, J. H. Choi, M. K. Kim, H. C. Choi, J. H.
Jeong, et al., “Therapeutic Efficacy of Vertebroplasty in
Osteoporotic Vertebral Compression Fractures with Avas-
cular Osteonecrosis: A Minimum 2-Year Follow-Up
Study,” Spine (Phila Pa 1976) , Vol. 37, No. 7, 2012, pp.
E423-429.