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Vascular and Interventional Radiology |
1 From the Department of Diagnostic and Interventional Neuroradiology (H.M.B, J.V., D.L., E.C., B.J., J.C.), Department of Anesthesiology (M.R.), and Department of Public Health (P.A.), Groupe Hospitalier Pitié-Salpêtrière, Assistance Publique des Hôpitaux de Paris, Université Pierre-et-Marie Curie Paris VI, 47-83 boulevard de l'Hôpital, 75651 Paris Cedex 13, France. Received May 9, 2004; revision requested July 20; final revision received February 10, 2005; final version accepted March 9. H.M.B. supported by the Collège de Médecine des Hôpitaux de Paris, Paris, France; the Consejo Nacional de Ciencia y Tecnología de México, Mexico City, Mexico; and the Secretaría de Salud de México, Mexico City, Mexico. Address correspondence to H.M.B. (e-mail: hector.barragan{at}psl.ap-hop-paris.fr).
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
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Materials and Methods: This study had institutional review board approval; patient informed consent for the review of records and images was not required. In 2 years, 117 patients (38 men [32.5%] and 79 women [67.5%]; mean age, 58.2 years) underwent 159 fluoroscopy-guided PV procedures to treat 304 vertebrae. Spinal metastases included osteolytic, osteoblastic, and mixed lesions. Complications were characterized as local or systemic. Evaluated data included immediate imaging findings (on radiographs and computed tomographic scans) and clinical findings at 30-day follow-up. 
2 or Fisher exact testing was performed for univariate analysis of variables.
Results: The primary cancers were breast cancers (45.3%), lung cancers (14.5%), myeloma (7.7%), or other cancers (32.5%). Among the 423 cement leakages identified, 332 (78.5%) were vascular and 91 (21.5%) were nonvascular. Vascular leaks were classified as venous epidural leaks, paravertebral and foraminal plexus leaks, and leaks to the vena cava, while nonvascular leaks included puncture trajectory leaks, paravertebral soft tissue leaks, and diskal leaks. Patients with nonvascular leaks were asymptomatic. Eight (6.8%) patients experienced complications, and seven of these complications were symptomatic. Among these eight patients, six (5.1%) had local complications (puncture site hematoma in two patients and radicular pain [successfully treated with nonsteroidal anti-inflammatory drugs or corticosteroids] in four patients), and two (1.7%) had systemic complications (pulmonary embolism resulting from cement migration through the vena cava). One of the latter patients died. Univariate analyses revealed a significant association between cement migration through the vena cava and pulmonary embolism (P = .001) but not between foraminal venous leakage and radicular pain (P = .123).
Conclusion: Despite numerous technical incidents (leaks), PV-induced complications were rare, leading to the hypothesis that systemic complications are a consequence of intravascular leakage while local complications are a consequence of cement-related irritation, compression and/or ischemia, and/or needle-induced trauma.
© RSNA, 2006
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
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Since our evaluation of the overall rate of complications of PV for the treatment of spinal metastases early in our experience (3,5), more than 1000 PVs have been performed in our department. Thus, the aim of this study was to retrospectively evaluate the complications of PV performed with polymethylmethacrylate (PMMA) cement for treatment of the pain caused by spinal metastases.
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MATERIALS AND METHODS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
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Patients
Consecutively treated patients with cancer involving spinal metastases were included over a 2-year period (2001–2002). Each patient was referred to our department by his or her attending clinician, oncologist, radiotherapist, or orthopedist for the treatment of pain related to spinal metastasis. Indications for PV were excruciating pain and when adverse effects (constipation, urinary retention, and/or confusion) to opioid treatment or opioid tolerance developed in patients with controlled pain. All patients had clinical and imaging evidence of spinal metastases. Imaging studies included spine magnetic resonance (MR) imaging, technetium 99m pertechnetate bone scintigraphy, and computed tomography (CT). The pre-PV work-up included physical examination, 1.5-T MR imaging (Signa LX; GE Medical Systems, Milwaukee, Wis) of the spine with sagittal T1-weighted images acquired before and after the intravenous administration of a gadolinium chelate (Dotarem; Guerbet, Roissy-Charles-de-Gaulle, Île de France, France) (6–8), and CT (Somatom Plus 4; Siemens, Erlangen, Germany) focused on the symptomatic vertebral level and performed with standard and bone windows. The CT findings enabled us to classify spinal metastases as osteolytic, osteoblastic, or mixed lesions. Whenever doubt persisted, the lesion was sampled for biopsy during the PV procedure.
We excluded patients in whom PV was not appropriate—for example, patients with diffuse nonfocal back pain, complete vertebral destruction, posterior arch malignancies, spinal cord compression, epidural involvement documented at spinal MR imaging, local infection at the puncture site, septicemia, and/or a contraindication to neuroleptanalgesia. Relative contraindications included transient chemotherapy-induced hematologic anomalies such as a low white blood cell count (<2.5 x 103/µL [2.5 x 109/L]), a low platelet count (<100.0 x 103/µL [100.0 x 109/L]), a partial thromboplastin time greater than 1.5 times the upper limit of the normal value, and an international normalized ratio higher than 1.5; patients underwent PV only after these values had returned to normal levels (9).
A total of 159 PV procedures were performed to treat 304 vertebral bodies in 117 consecutive patients: 38 (32.5%) men and 79 (67.5%) women (male-female ratio, 0.48). The mean age of the entire patient cohort at the time of PV was 58.2 years ± 12.5 (standard deviation) (range, 26.6–88.2 years). For men, the mean age was 62.9 years ± 10.4 (range, 45.9–88.2 years), while for women, it was 55.9 years ± 12.8 (range, 26.6–81.7 years).
PV Procedure
PV was performed with a digital subtraction angiography unit with a C-arm (Angiostar; Siemens) while patients were in a state of neuroleptanalgesia that had been induced with intravenous propofol (Diprivan; Astra-Zeneca, Rueil-Malmaison, France) alone or in combination with intravenous alfentanyl (Rapifen; Janssen-Cilag, Issy-les-Moulineaux, France) and midazolam hydrochloride (Hypnovel; Roche, Neuilly, France). Local anesthesia (1% lidocaine, Xilocaïne; Astra, Sodertalje, Sweden) was also administered subcutaneously with fluoroscopic guidance. General anesthesia with orotracheal intubation was used only when the anesthesiologist (M.R.) considered it necessary.
Anatomic landmarks and structures differ according to the vertebral level. In the cervical spine, a right anterolateral approach was used. The carotid-jugular complex was displaced gently downward and laterally with the fingertips and separated from the trachea and esophagus to expose an entry site for the needle. Depending on the site of the lesion in the thoracic and lumbar regions, four different approaches were possible: the transpedicular approach, with reliance on vertebral pedicles as landmarks; the posterolateral approach, which was initiated at a point located 10 cm outside the midline that corresponded to the vertebral spinous process and was identified with fluoroscopic guidance; the intercostovertebral approach, which was used when the pedicles were too small; and the anterolateral approach, which was used to treat lesions located in the first and second thoracic vertebrae.
Beveled 10–15-gauge bone needles with no handle (Escoffier Frères, Thonons-les-Bains, France) were inserted into the vertebral body with fluoroscopic guidance provided by the digital subtraction angiography unit. A bilateral transpedicular approach was used at the thoracolumbar spine in all the patients in whom it was possible; however, when the lesion involved the pedicles, a posterolateral approach was selected. In the cervical spine, the right anterolateral approach was used.
When the imaging findings were not conclusive as to the cause of the lesion, a bone biopsy was performed before PMMA injection by using a coaxial system with a 14-gauge, 19-cm-long bone biopsy needle (Cook, Bloomington, Ind). Then, PMMA cement (Surgical Simplex P; Striker-Howmedica, Limerick, Ireland) mixed with tungsten powder (Balt, Montmorency, France), which enhances the cement's radio-opacity, was injected with fluoroscopic guidance until homogeneous filling of the target vertebra was achieved. During the intervention, the following information was carefully monitored and recorded in each patient's medical file: the approach used, whether or not biopsy was performed, the total volume (in milliliters) of the injected cement, and whether cement leakage or migration occurred. If leakage through the epidural veins; the anterior, anterolateral, or lateral part of the paravertebral plexus; or the foraminal veins developed, the injection was stopped temporarily and restarted a few seconds later. If the leakage increased, the needle was rotated 180° or pulled back 1–2 cm before the injection was restarted and continued until homogeneous vertebral filling was achieved. The injection was definitively stopped if cement migration through the vena cava was observed. All PV procedures were performed by the same physician (J.C., who had 11 years of experience in performing PV).
Immediately after PMMA injection, standard anteroposterior and lateral radiographs were obtained. Afterward, patients were transferred to the surveillance unit, where they remained for 30 minutes to 2 hours. When they had fully recovered from neuroleptanalgesia, patients underwent transverse helical CT scanning with a collimation of 2 mm, a pitch of 1, 1.5-mm reconstruction intervals, 140 kV, 206 mAs, and a 170-mm field of view. All images were reconstructed with a bone algorithm; a multiplanar reconstruction algorithm was also used for the sagittal and coronal images.
Follow-up
Patients could be discharged from the hospital as early as 24 hours after the PV procedure. All patients were examined 30 days after PV so that clinical results and treatment-related complications could be evaluated. Clinical complications were evaluated during and after PV by the same anesthesiologist (M.R., who had 11 years of experience in treating this condition). Technical incidents were assessed by the physician who performed the PV procedures (J.C.).
Record Review
Clinical and imaging records acquired before and after PV were reviewed by the same observer (H.M.B.). Data collected included those related to histopathologic confirmation of the primary malignancy site and the anesthesia protocol used, those acquired during periprocedural surveillance performed during the patient's hospitalization for PV (from the time of admission to the time of discharge from the hospital), and those related to post-PV complications (local, systemic, or both). Complications were considered immediate when they developed within 24 hours after PV and late when they appeared up to 30 days after PV. Local complications were defined as puncture site hematoma, abscess, transitory deglutition impairment, radicular pain, neurologic deficit (caused by spinal cord or radicular compression), and increased degree of pain at the treated vertebral body. Systemic complications were defined as pulmonary embolism (PE), septic shock, respiratory failure, and cardiogenic shock. The following clinical variables 30 days after PV were considered: increased pain in the treated vertebral body, radicular pain, PE, and death. Technical incidents were assessed according to the level of the treated vertebra, while local and systemic complications were evaluated on a per-procedure basis.
The data collected included the following: the number of PV procedures per patient; the number of vertebrae treated per PV procedure; the level of each treated vertebra (cervical, thoracic, lumbar, or first sacral); the CT classification of the vertebral metastasis as osteolytic, osteoblastic, or mixed; the presence or absence of cortex disruption; the presence or absence of posterior wall rupture; the gauge of the needle used at PV; the approach used at PV; and the degree of PMMA filling (measured in milliliters and estimated as a percentage on the basis of findings on transverse, sagittal, and coronal CT images). Additionally, we recorded the presence or absence of cement leaks, which were classified on a topographic basis as vascular leaks or nonvascular leaks. Vascular leaks (if present) were reported as epidural venous leaks, paravertebral venous plexus leaks (which were subclassified as anterior, anterolateral, or lateral venous leaks), foraminal venous plexus leaks, and leaks to the vena cava. Nonvascular leaks were reported as puncture trajectory leaks, disk leaks, and/or spinal canal leaks. All immediate post-PV data were obtained by evaluating standard spinal radiographs in anteroposterior and lateral views and transverse helical CT scans with sagittal and coronal multiplanar reconstructions.
Statistical Analysis
First, a descriptive statistical analysis was performed. Dichotomous and categorical data are reported as numbers and percentages. Continuous data are reported as means ± standard deviations and ranges when the distribution was normal and as medians and interquartile ranges (ie, 25th and 75th percentiles) when the distribution was not normal. Sex, age, events that occurred during the peri-PV surveillance period, primary malignancy site, and immediate and late complications were recorded for every patient. The anesthesia protocol and the number of treated vertebrae were evaluated on a per-PV-procedure basis. The CT appearance of metastases, the presence or absence of anterior or lateral cortex rupture, the presence or absence of posterior wall rupture, the treated vertebral level, and technical incidents were evaluated on a per-vertebral-body basis.
Second, univariate analyses were performed to search for statistically significant associations between cement leakage and clinically relevant complications (defined as complications requiring medical surveillance or intervention). According to this rationale, the following paired dichotomous variables were tested: cement leakage through the foraminal veins and radicular pain (Fig 1) and cement leakage through the vena cava and PE (dichotomous variables) (Fig 2). We used a 2 test for categorical variables (SPSS, version 11.0 for Macintosh operating system X; SPSS, Chicago, Ill) and Fisher exact tests when the expected values in the 2 x 2 contingency table for the 2 test were less than 5 in at least one cell (StataCorp 2001, release 7.0 for Macintosh; Stata, College Station, Tex). For continuous variables, the Student t test for independent samples (SPSS) was used. A P value of less than .05 was considered to indicate a significant difference.
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RESULTS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
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The mean volume of PMMA injected into a vertebral body was 4.7 mL ± 1.55, while the mean percentage of filling (evaluated on transverse, coronal, and sagittal CT images) was 59.2% ± 20.72. Filling was considered to be excellent (percentage of filling, 67%–100%) in 150 (49.3%) of the 304 treated vertebrae, good (percentage of filling, 34%–66%) in 109 (35.9%) of the vertebrae, and poor (percentage of filling, 0%–33%) in 45 (14.8%) of the vertebrae.
Technical Incidents
During the 159 PV procedures performed, we identified a total of 423 leakages of PMMA cement from the 304 treated vertebrae, with a median of 2.0 (range, 1–5) extravertebral leakages per treated vertebra. Three hundred thirty-two (78.5%) leakages, all of which were located in the venous network, were classified as vascular leakages, while the remaining 91 leakages (21.5%) were nonvascular. Among the 423 treated leakages, venous cement leakage was located topographically in the epidural veins in 148 (35.0%), in the paravertebral plexus veins in 103 (24.3%), in the anterolateral paravertebral plexus veins in 39 (9.2%), in the lateral paravertebral plexus veins in 18 (4.3%), and in the foraminal veins (posterolateral paravertebral plexus) in 19 (4.5%). All five (1.2%) cement leakages that led to migration through the vena cava were directly observed during the procedure because all PV procedures were performed with fluoroscopic guidance.
Among the 91 nonvascular extravertebral cement leakages, 22 (5.2%) were classified as being topographically located in the puncture trajectory; 34 (8.0%), as being located in the paravertebral soft tissue (Fig 3); and 29 (6.9%), as being located in the disk (Fig 4). The remaining six (1.4%) leakages were thought to constitute an extradural localization of spinal canal leakage. None of the patients with nonvascular cement leakage reported any symptoms during the immediate post-PV period or at clinical follow-up 30 days later.
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Local complications.—A puncture-site soft-tissue hematoma was detected in two patients (1.7%) clinically and with CT imaging; neither patient developed hemodynamic instability, and both hematomas resolved spontaneously during the following 2 weeks. Radicular pain occurred in four (3.4%) patients and was attributed to ipsilateral foraminal venous cement leakage in two patients. Neither vascular nor nonvascular cement leakages were identified as responsible for the radicular pain in the other two patients. A regimen of 100 mg of ketoprofen (Profenid; Sanofi-Aventis, Paris, France) two or three times daily or a single intravenous bolus of 120 mg/dL of methylprednisolone (Solu-Medrol; Pfizer, Sandwich, England) followed by 32 mg per day by mouth (Médrol; Pfizer) for 5 days was prescribed, and, at 30 days after PV, the radicular pain had resolved in the four patients and none of them required surgical debulking of cement. No patient developed a neurologic deficit related to spinal cord compression or radicular compression in this study.
Systemic complications.—Two patients developed PE that was identified within 30 days of follow-up, but only one patient was symptomatic, even though PMMA cement migration from the paravertebral venous plexus through the vena cava had been detected in both patients during PV and their postprocedure chest radiographs and CT scans showed hyperintensities related to the presence of PMMA cement in the arterial pulmonary vascular network. One of the patients who developed PE—a patient with breast cancer—did not develop pulmonary or hemodynamic signs or symptoms of PE, and no treatment was prescribed. The other patient, who had lung adenocarcinoma, developed ventilatory and hemodynamic symptoms of PE; despite treatment with oral anticoagulants, this patient died 8 days after PV. No evidence of coexistent deep venous thrombosis was identified with Doppler ultrasonography performed as part of the standard work-up for PE in either patient.
Although cement migration–attributed PE was symptomatic in only one patient, it was recorded as a complication in both patients. Considering all these data, at 30 days after PV, the per-procedure and per-patient morbidity rates were 5.0% (eight of 159 procedures) and 6.8% (eight of 117 patients), while the single death recorded meant that the procedural and patient mortality rates were 0.6% (one of 159 procedures) and 0.9% (one of 117 patients).
According to results of our univariate analysis, radicular pain and foraminal venous cement leakage were not associated with each other (P = .123, Fisher exact test) (Table 3). However, cement migration through the vena cava was significantly associated with PE (P = .001, Fisher exact test) (Table 4). No variable was associated with increased pain at the treated vertebral body after PV.
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
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Spinal metastases are expected to develop in 27% of cancer patients (13). The metastasis rate depends on the type of primary cancer—for example, dissemination occurs in 80% of men with prostate cancer, in 50% of women with breast cancer, and in 30% of patients with lung, thyroid, or kidney cancer (13). The clinical manifestations of spinal metastases range from asymptomatic lesions to pathologic vertebral fractures, radicular pain, motor and/or sensory deficits caused by radicular compression, and/or spinal cord compression (14). Management of spinal metastases consists of bed rest and the use of braces, nonsteroidal anti-inflammatory drugs, opioids, radiation therapy, and/or surgical decompression (15–17), as well as PV with PMMA cement, a technique developed in France by Galibert et al (18).
Within the first 48 hours after the procedure, PV achieves an analgesic effect that persists for at least 6 months (19). This effect is attributed to the stabilization that results from preventing the micromovements responsible for vertebral pain. Likewise, PV may halt the progression of vertebral collapse by strengthening the vertebral body. Other hypotheses for the effect of PV are the destruction of nerve endings by the exothermic reaction occurring during polymerization and the idea that PMMA has an inherent tumoricidal or cytotoxic effect (20). Factors favoring the rapid development of PV include the high reproducibility of the results of this procedure when it is performed by well-trained teams, the minimally invasive nature of this procedure (as compared with surgical stabilization) in patients with comorbidities and limited physiologic reserves, and a short and well-tolerated recovery.
The relatively common technical incidents and the rate of complications at PV have previously been discussed (3,4,19,21,22). Deramond et al (4) and Chiras and Deramond (5) reported that PV-associated complications were more common in metastatic lesions (at a rate of 5%–10%) than in osteoporotic lesions (1%–3%) or vertebral hemangiomas (2%–5%). Our findings are in agreement with theirs.
In an earlier study (3) of 37 patients treated with PV, five (13.5%) experienced local complications. Three patients experienced radicular pain, which resolved after treatment with nonsteroidal anti-inflammatory drugs in two patients; the remaining patient required surgical PMMA removal. Deglutition was transiently impaired in two other patients (5.4%).
Our local complication rate was 5.1% (six of 117 patients). Local complications mainly consisted of radicular pain (in four [3.4%] patients), and no deglutition impairment occurred after 32 cervical vertebrae were treated with PV. A possible explanation for the diminution in the rate of local complications in the present study could be the good opacification of PMMA accomplished with tungsten; opacification has already been reported to be a key factor in the prevention of complications (3,5).
Cotten et al (21) evaluated the clinical results of PV with CT and observed complications in 30 patients with osteolytic metastases and 10 patients with myeloma. Technical incidents or PMMA leaks were very common, occurring in 29 (72.5%) of the 40 patients, and were distributed as follows: 51.7% (15 of 29 patients) in the spinal canal, 27.6% (eight of 29 patients) in the neural foramina, 27.6% (eight of 29 patients) in adjacent disks, 72.4% (21 of 29 patients) in the paravertebral tissue, and 6.9% (two of 29 patients) in the lumbar venous plexus. The posterior wall ruptured in 13 patients (32.5%). Only three (7.5%) of the leaks were symptomatic; these leaks manifested as radicular pain. One of the leaks resolved with nonsteroidal antiinflammatory drug treatment, and the other two necessitated decompression surgery. Asymptomatic vertebral disk leakage occurred in eight (27.6%) of 29 patients. Finally, 14 (48.27%) paravertebral leakages were a consequence of cortical osteolysis. Our findings agree with these findings of Cotten et al.
In our study, we were able to establish that local PE was significantly associated with intravascular leakage of PMMA cement. On the other hand, local complications may have different causes that include foraminal venous leakage (which causes radicular irritation owing to polymerization-generated heat or ischemia), soft-tissue leakages through the pedicle into the conjugate foramen (resulting in compression of the nerve root), and an inflammatory response to the trauma of needle insertion. The fact that none of our patients who experienced radicular pain required surgical removal of cement and the fact that their pain resolved with nonsteroidal antiinflammatory drugs or corticosteroids support these hypotheses. Other authors (23,24) have also reported that some cases of radicular pain could be associated with cortical leakage of cement into the foraminal space.
Furthermore, we observed that cement migration through the vena cava could be asymptomatic or associated with clinically full-blown PE. PE management can require different strategies, ranging from clinical follow-up (22,25) to the use of oral anticoagulative drugs (26,27) or even embolectomy in selected cases (28,29). However, our knowledge about the appropriate treatment of PMMA-associated PE is limited, and additional studies are needed to establish the optimal approach to management of this potentially life-threatening complication.
Our study had some limitations. First of all, owing to the retrospective design of the study, selection bias was unavoidable because we selected patients with spinal metastases who were treated in a referral center. However, by reporting findings in all of the consecutive patients treated over a 2-year period, we have attempted to minimize this methodologic weakness. Second, the occurrence of only two PEs precludes the use of multivariate analysis. Nevertheless, we report our experience in the treatment of 117 patients with spinal metastases, among whom nine (7.7%) had myeloma. Our findings indicate that PV with PMMA can be an effective tool for combating the excruciating pain associated with spinal metastases, including myeloma.
In conclusion, local and systemic complications of PV with PMMA were rare, and only one death was recorded. Furthermore, we were able to establish a significant association between cement migration through the vena cava and PE. However, the absence of an association between foraminal venous leakage of cement and radicular pain might support the hypothesis that the local and systemic complications observed in our study originated from different leakage pathways.
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ACKNOWLEDGMENTS |
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FOOTNOTES |
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Abbreviations: PE = pulmonary embolism • PMMA = polymethylmethacrylate • PV = percutaneous vertebroplasty
Authors stated no financial relationship to disclose.
Author contributions: Guarantor of integrity of entire study, J.C.; study concepts, J.C., E.C., H.M.B.; study design, H.M.B., D.L., M.R.; literature research, D.L.; clinical studies, M.R.; data acquisition, H.M.B., J.V.; data analysis/interpretation, E.C., P.A., J.V.; statistical analysis, P.A.; manuscript preparation, H.M.B.; manuscript definition of intellectual content, J.C., H.M.B.; manuscript editing, J.V.; manuscript revision/review, B.J., J.C., J.V.; manuscript final version approval, J.C., H.M.B.
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