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Vertebroplasty-percutaneous cement augmentation of osteoporotic vertebrae is an efficient procedure for the treatment of painful vertebral fractures. From a prospectively monitored series of 70 patients with 193 augmented vertebrae for osteoporotic and metastatic lesions, we analysed a group of 17 patients suffering from back pain due to osteoporotic fractures. The reinforcement of 45 vertebral bodies in these patients led to a significant and lasting pain reduction (P < 0.01). The presented technique is useful, as, in one session, at least four injections can be performed when required, allowing the prophylactic reinforcement of adjacent vertebrae as well. The use of a low-viscosity polymethyl methacrylate (PMMA) in combination with a non-ionic liquid contrast dye provides a reliable and safe procedure. Extraosseous cement leakage was seen in 20% of the interventions; however, none of them had clinical sequelae.
Eur Spine J (2000) 9 : 445450 Springer-Verlag 2000ORIGINAL ARTICLEP. F. HeiniB. WlchliU. BerlemannPercutaneous transpedicular
vertebroplasty with PMMA:
operative technique and early resultsA prospective study for the treatment
of osteoporotic compression fracturesReceived: 31 January 2000Revised: 18 May 2000
Accepted: 22 May 2000P. F. Heini () B. Wlchli U. BerlemannDepartment of Orthopaedic Surgery,
Spine Service, Inselspital,
University of Bern, Switzerland
e-mail: [email protected],
Tel.: +41-31-6322111,
Fax: +41-31-6323600P. F. HeiniDepartment of Orthopaedic Surgery,
Inselspital Bern, Freiburgstrasse,
3010 Bern, SwitzerlandAbstract Vertebroplasty-percutaneous cement augmentation of osteoporotic vertebrae is an efficient procedure for the treatment of painful
vertebral fractures. From a prospectively monitored series of 70 patients
with 193 augmented vertebrae for
osteoporotic and metastatic lesions,
we analysed a group of 17 patients
suffering from back pain due to osteoporotic fractures. The reinforcement of 45 vertebral bodies in these
patients led to a significant and lasting pain reduction (P < 0.01). The
presented technique is useful, as, in
one session, at least four injections
can be performed when required, allowing the prophylactic reinforcement of adjacent vertebrae as well.
The use of a low-viscosity polymethyl methacrylate (PMMA) in
combination with a non-ionic liquid
contrast dye provides a reliable and
safe procedure. Extraosseous cement
leakage was seen in 20% of the interventions; however, none of them
had clinical sequelae.Key words Vertebroplasty PMMA
Osteoporosis AugmentationIntroductionThe technique of percutaneous vertebroplasty with polymethylmethacrylate (PMMA) was first introduced as an
augmentation procedure for the treatment of vertebral angiomas by Galibert et al. in 1987 [9]. Following encouraging early clinical results, particularly with respect to
pain relief, indications for PMMA augmentation were extended and comprise at present the treatment of metastatic
osteolytic bone disease, myeloma, and, more recently, osteoporotic compression fractures of the spine as well [6, 8,
11, 18]. Biomechanical studies have shown significant increases in stability parameters following augmentation
with PMMA and also calcium phosphate cements [1, 3,
15, 16, 17]. Clinical experiences, however, are still sparse.This study reports our technique and experience with
percutaneous transpedicular vertebroplasty in the treatment of patients suffering from severe disabling focal
back pain due to osteoporotic insufficiencies and vertebral
compression fractures.Materials and methodsOperative techniqueThe presented technique allows four injections to be carried out in
one session under local anaesthesia, i.e. either four vertebrae unipedicularly or two vertebrae bipedicularly.Patients are placed in a prone position on a radiolucent operating table. An i.v. line is established with an anaesthetist on standby, continuously monitoring the vital signs. Following fluoroscopic localisation of the levels to be augmented, the skin and soft
tissues over the pedicles are anaesthetised with 1% mepivacaine
hydrochloride, with deep injections down to the periosteum (Fig. 1 a).
Under fluoroscopic anteroposterior control, a skin stab incision is
established and a 2.0-mm K-wire is guided into the pedicle of each
vertebra to be reinforced. In severe osteoporosis, the wire can be
advanced by hand, otherwise some gentle hammer blows may be
necessary (Fig. 1 b). Under lateral projection control, the wires are
adjusted to the appropriate depth, i.e. the centre of the vertebral
body. Bone marrow biopsy needles (7 or 8 G, Somatex, Berlin,
Germany) are guided over the K-wires, which are then removed
(Fig. 1 c). The free passage in front of the needle is checked by a
blunt probe.The augmentation material consists of a low-viscosity bone cement (Palacos E-flow, Essex Chemie, Lucerne, Switzerland). In446Fig. 1 Intraoperative setting:
a localisation of the pedicles
and local anaesthesia of the
skin and soft tissue; b placement of K-wires under image
control; c bone marrow biopsy
needles in place; d injection of
bone cement by 2 cc syringesa bc dorder to enhance the radiographic visibility, a non-ionic liquid contrast dye is added to the cement during the mixing procedure
(Iopamiro 300, Bracco, Milan, Italy) in the ratio of 10 cc of contrast dye per one portion of PMMA. The material is filled into 2-cc
standard syringes.Two minutes into the cement curing, filling of the vertebral bodies is commenced under continuous fluoroscopic control in the lateral view (Fig. 1 d). The cement remains injectable for the following
2 or 3 min. The simultaneous filling of two vertebral bodies is possible. The flow of the cement must be monitored very carefully, and
should behave like a growing cloud (Fig. 2). Cement leaks posteriorly into the spinal canal and anteriorly through the nutritional
vessels must particularly be avoided. The maximum amount of cement to be injected is determined during the procedure, as with any
cement extrusion the filling is stopped. However, in these cases the
needle position can be slightly altered, which may allow further filling with less liquid cement. In cases of normal filling (growing
cloud) the augmentation is stopped with visible filling of the entire
vertebral frame. Prior to withdrawal of the needles, the material
should be allowed to fully cure to avoid dragging of cement into the
soft tissues.Additional analgesia may be needed either during placement of
the K-wires and needles or, particularly, during the injection of cement, which sometimes is felt as regional low back pain. In these
cases i.v. administration of morphine (Rapifen = alfentanilhydrochloride) also helps the patients to maintain the prone position
for the required 4560 min of the entire procedure.PatientsAt present, our prospectively monitored series contains 70 patients
with 193 augmented vertebrae treated for osteoporosis and metastatic lesions of the lumbar and thoracic spine. The paper presented
here analyses the first 45 percutaneous vertebroplasties for osteoporotic fractures, with a minimum follow-up of 1 year (Table 1,
Table 2). This includes 17 consecutive patients, 15 women and
2 men, aged 5086 years (mean 74 years). All patients were suffering from disabling back pain refractory to conservative treatment for at least 4 weeks, including analgesics, physiotherapy, and
braces in three cases. Most of the patients had initially been treated
at other institutions, and were referred because of persistent pain.
All patients had radiographic evidence of progressive or new vertebral compression fractures. This was related to the exacerbation
of pain after a minor trauma (simple fall, sitting down suddenly).
Further, during physical examination, in our patients the region of
pain seemed equivalent to the radiological changes. However, the
exact clinical determination of a painful level is difficult. Twelve
patients showed fractures due to age-related osteopoenia, three patients had received long-term oral steroids for chronic conditions,447a bFig. 2 a, b Clinical example. An 80-year-old female, smoker, otherwise healthy, with disabling back pain due to fractures of the
midthoracic vertebrae (a). After augmentation of the fractured and
adjacent vertebrae, the patient presents painfree (b)Table 1 Data on the patients
treated in this series (VAS visual
analogue scale, FU follow-up)Initials Age/sex Levels Levels augmented VAS score VAS score VAS score
fractured preop postop at 3 mo./1 year FUS. W. 86/M L3 L3 Bi 10 0 0/1B. B. 86/F L1 T11L2 Mono 8 1 0/2Z. E. 84/F L1L3 L1L3 Bi 6 5 2/2B. I. 81/F T11L1 T11L2 Mono 10 6 3/3F. M. 80/F L1L3 L1L4 Mono 7 3 0/3H. M. 78/F L4 L4 Bi 8 2 6/4B. E. 77/F L3, L4 L3, L4 Bi 6 0 4/4S. H. 75/M L2L5 L2L5 Mono 6 5 2/3S. R. 75/F L1L3 L1L4 Mono 8 4 2/4S. I. 72/F L4 L3L5 Mono 8 6 2/3C. A. 71/F L1 L1 Mono 6 1 1/2K. A. 61/F T11, L1 T11L1 Mono 9 8 6/6F. R. 59/F T12L2, L4 T12L2, L4 Mono 8 5 3/2S. B. 50/F T11 T11 Mono 7 2 6/6G. A. 81/F L2, L4 L2, L4 Mono 5 1 1/1E. H. 72/F L3, L4 L3, L4 Mono 7 5 7/7F. P. 80/F T6T7 T6T9 Mono 9 1 2/2448Table 2 Distribution of levels augmentedLevel No. of segments augmentedT6, T7, T8, T9 4 (1 each)T11 4T12 3L1 7L2 8L3 8L4 9L5 2Total 45Fig. 3 Box plot representing the visual analogue (VA) scale of
pain assessment prior to treatment, 1 day after, 3 months later and
1 year postoperatively. There is significant pain relief immediately
after the procedure (Wilcoxon signed rank test P < 0.01)and one patient had severe osteopenia due to secondary hyperthyroidism. Plain radiographs were obtained prior to intervention
in all patients. Three patients were further evaluated with computed tomography (CT) to assess the spinal canal and the posterior
vertebral wall. Clinical and radiological follow-up controls were
performed at 1 day, 12 weeks and 1 year post intervention. Pain intensity was assessed using a numerical scale (010), 0 points corresponding to no back pain at all and 10 points corresponding to
the most severe pain ever experienced.In four patients only one level was reinforced, in three patients
two levels, and in a further three patients three levels were treated,
with the remaining seven patients being augmented at four levels
(Table 1). The extent of augmentation was decided according to
the radiological appearance of the spine, i.e. in cases with a singlelevel fracture and normal vertebral shape of the adjacent levels,
one vertebra was augmented only. Patients were mobilised a few
hours after the procedure. For local pain control, all patients received mild pain medication (paracetamol) for 2448 h.ResultsAll 17 procedures were successfully performed under local anaesthesia in combination with slight sedation monitored by the anaesthetist. None of the procedures lasted
more than 1 h. Four patients reported discomfort with local low back pain upon PMMA injection.Thirty-eight of the 45 vertebral bodies were augmented
through one pedicle; six bodies were injected through
both pedicles. The mean volume of filling per vertebra
was 5.9 ml PMMA (48 ml). Extraosseous cement leakage was noted in eight vertebral bodies (20%), five times(12.5%) into the paravertebral soft tissues, twice (5%)
into the spinal canal and once (2.5%) into a segmental
vein. All of these cement extrusions remained without
clinical sequelae.All patients reported a considerable pain benefit following the procedure. The median scores of pain intensity
were reduced significantly (P < 0.01, Wilcoxon signed
rank test) (Fig. 3). With the exception of one patient, all
patients were able to get out of bed 34 h after intervention, and the mean hospital stay was 2.6 days (15 days).At 3 months follow-up, radiographs revealed further
compression of an augmented vertebral body in one case.
The clinical rating stayed unchanged. At 1 year follow-up,
all injected vertebrae seemed radiologically stable; however, at this stage, additional new compressions of nonreinforced vertebral bodies were noted in two patients
with secondary osteoporosis at T9 and T10 respectively.
Again, at this time the pain scale remained unchanged.DiscussionThe spine is the most common site of fracture in patients
with osteoporosis. In the United States, 25% of women
over the age of 70 and 50% of women over the age of
80 years show evidence of vertebral fractures, the majority of which occur in the midthoracic region and the thoracolumbar junction [12,13]. The morbidity associated
with osteoporosis and vertebral fractures has an enormous
socio-economic impact [2].Percutaneous vertebroplasty (PVP) with PMMA offers
an efficient tool in augmenting vertebral bodies, which
has been clearly demonstrated in biomechanical studies
[12,13]. Clinical experience of more than 10 years in the
treatment of haemangiomas, metastatic lesions and, more
recently, osteoporotic deficiencies are also encouraging
[5, 8, 9, 10, 11, 14,18]. Our series confirms these results,
as all patients reported pain relief following augmentation. The intervention can be performed under local
anaesthesia and slight sedation as an outpatient procedure,
despite the fact that mainly elderly patients are treated.
The average stay of 2.6 days for our patients is only due
to the fact that prior to our intervention most patients had
been treated as in-patients in the internal department. The
presented technique allows for the reinforcement of four
vertebrae in less than 1 h. In contrast to other reports, no
CT-guided puncture of the vertebral pedicles, nor a
venography prior to cement injection, was used [4, 5, 7,9].
Care has to be taken concerning the distribution of cement, and continuous monitoring of cement flow at any
time during the injection procedure is mandatory. Never-449theless, extravasation of cement did occur in 20% of our
cases. However, no serious clinical sequelae were observed, as the vast majority extravasations seem clinically
irrelevant [11]. With advanced destruction of the vertebral
body, the risk of cement leakage increases [19]. Cotten et
al. observed extrusions in 29 out of 40 injected vertebral
bodies with metastatic diseases, and two patients out of
37 required decompressive back surgery for severe neurological complications [5].The minimum amount of cement required for a therapeutic effect is not exactly known. In a series of 37 patients, Cotten observed a reduction of pain after filling
vertebral bodies with between 5.5 and 7 cc cement, but no
correlation between the volume of filling and the amount
of pain relief was found [5]. The antalgic effect of PMMA
is most probably based on its mechanical effect, through
reinforcement of the trabecular pattern at the fracture site[18]. A thermal or chemical destruction of nerve endings
also seems feasible. In our series, pain was reduced with a
mean of 5.9 cc PMMA per vertebral body and, with the
exception of one vertebra, further collapse was prevented.
This single case of collapse may have been due to an insufficient filling, of 2.5 cc PMMA. Thirty-four of the
40 vertebrae were injected through one pedicle only. We
did not see any collapse of the non-injected side, which
confirms the results of a recent biomechanical study reporting a comparable biomechanical efficacy of unipedicular versus bipedicular vertebroplasties [17].A further question to be discussed is whether the reinforcement of the affected and already fractured vertebrae
alone is sufficient, or whether a more extensive treatment
including the adjacent levels should be performed. The
reported experience in the literature is based on the treatment of fractured vertebrae in most cases a single vertebra only, and focusses on acute pain relief. So far,
long-term follow-up and consequences of vertebroplasties on the overall alignment of the spine have not been
addressed. At 1 year follow-up, two of our patients
showed vertebral fractures adjacent to the augmentation
area. We do not know whether these fractures were
caused by the underlying disease or whether an increased
stiffness and stress arising adjacent to an augmented area
plays a role.Also, limits and timing of cement augmentation are
difficult to determine. As a consequence of the present
study, we started to augment acute osteoporotic fractures
as well, in order to prevent collapse and achieve immediate pain relief. However, if the patients pain seems more
related to an advanced kyphotic deformation and loss of
spinal balance, more aggressive measures, such as multisegment correction and stabilization may be indicated. In
these cases, as with already collapsed single vertebrae, the
technique of vertebroplasty reaches a limit, as the cement
injection does not restore vertebral height. In addition, in
advanced kyphosis, we recommend magnetic resonance
imaging (MRI) evaluation of the thoracic spinal canal before considering cement augmentation. In cases of narrowing of the spinal canal, any indication for vertebroplasty should be considered very cautiously, as cement
leakage posteriorly may have severe consequences. In order to define these factors more clearly, a randomised controlled trial is planned to analyse the effect of preventive
reinforcement.At present, the only suitable material for injection is a
low-viscosity PMMA. Injectable calcium phosphate (CaP)
cements are already available, but for percutaneous application in the spine, their radio-opaqueness is insufficient
and does not allow a safe procedure. The corresponding
adaptations seem technically difficult to achieve. However, once available, these materials could represent an
improved solution for patients at risk of osteoporotic
spine fractures, as the potential disadvantages of PMMA,
e.g. toxicity, heat generation, etc, can be avoided. Also,
the osteoconductive properties of CaP materials could
bear potential benefits in the long term. This should be investigated further, including long-term assessment of augmentation materials in vivo.The results of the present study justify the generous
use of PMMA percutaneous vertebroplasty as a complementary therapy to standard medical therapy for patients
suffering from severe pain on the basis of osteoporotic
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