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Percutaneous polymethylmethacrylate vertebroplasty in the treatment of pain induced by metastatic spine tumor
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Surgical Neurology 70 (2008) S1:78 – S1:84 www.surgicalneurology-online.com
Pain
Percutaneous polymethylmethacrylate vertebroplasty in the treatment of pain induced by metastatic spine tumor Yuan-Yun Tseng, MD a , Yang-Lan Lo, MD a , Lih-Huei Chen, MD b , Po-Liang Lai, MD b , Shun-Tai Yang, MD a,⁎ a
b
Department of Neurosurgery, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan, 333, ROC Department of Orthopaedic Surgery, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan, 333, ROC Received 26 May 2008; accepted 29 August 2008
Abstract
Background: Metastases to the spine are a common problem in the large oncology center and represent a challenging problem in oncology practice. Patients with osteolytic metastases often experience intractable local and/or radicular pain. Therapeutic intervention can alleviate pain, preserve or improve neurologic function, achieve mechanical stability, and improve quality of life. Percutaneous polymethylmethacrylate vertebroplasty is an effective and relatively easy method of relieving patients' pain. Method: Between January 2002 and December 2006, 57 patients (78 vertebrae) with spinal metastatic tumor treated with PMMA vertebroplasty were enrolled in this study. The main indication for treatment was pain. Result: The mean value of VAS was 8.1 ± 0.67 preoperatively, and it significantly decreased to 3.8 ± 1.9 (1-8, P b .015) 1 day after vertebroplasty. The mean VAS value 6 months after vertebroplasty was 2.8 ± 2.0 (P b .001). The mean amounts of preoperative nonnarcotic analgesic and narcotic analgesic were 1.98 ± 1.4 and 1.19 ± 0.73, respectively. Postoperatively, the mean amounts of nonnarcotic and narcotic analgesic decreased to 1.35 ± 0.70 (P b .05) and 0.65 ± 0.53 (P b .05). A statistically significant reduction of nonnarcotic analgesic use was noticed in our study. Conclusions: Percutaneous vertebroplasty is a minimally invasive procedure that offers a remarkable advantage of effective and immediate pain relief with few complications. © 2008 Elsevier Inc. All rights reserved.
Keywords:
Vertebroplasty; Spinal metastatic tumor; Spinal instability; Pain
1. Introduction The skeletal system is the third most common site of metastases, with the spine being the most common site of skeletal metastasis [1]. Between 5% and 10% of all cancer patients develop spinal metastases during the course of their disease. Serious back pain, the most common presenting symptom in patients with metastatic spinal tumor, frequently Abbreviations: MRI, magnetic resonance imaging; PMMA, percutaneous polymethylmethacrylate; PVP, percutaneous vertebroplasty; VAS, visual analog scale. ⁎ Corresponding author. Tel.: +886 3 328 1200x2119; fax: +886 3 328 5818. E-mail address: [email protected] (S.-T. Yang). 0090-3019/$ – see front matter © 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.surneu.2008.08.078
precedes the development of other neurologic symptoms [5]. All physicians should recognize that spinal cord compression occurs not uncommonly as the initial manifestation of malignancy, and not only in the setting of established malignancy [25,16]. A correct and complete diagnosis of neurologic symptoms is necessary to give appropriate therapy. Magnetic resonance imaging has revolutionized assessment of metastatic spinal tumor. Magnetic resonance imaging is the most sensitive and specific modality for imaging spinal metastases; screening images of the entire spine reveal bone, epidural, and paraspinal tumors [26]. Percutaneous transpedicular vertebroplasty is a procedure in which PMMA bone cement is injected into a vertebral
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body. Vertebroplasty was developed in France in the late 1980s for the treatment of vertebral angiomas [11]. Initial success with this interventional procedure in hemangiomas has led to its use in the treatment of osteoporotic and osteolytic lesions [4,11,23]. Vertebroplasty is a minimally invasive procedure resulting in prompt pain relief and has a low complication rate [13,18,19]. The benefits of vertebroplasty for treatment of neoplastic disease were reported in a prior series. The aim of this retrospective observational study was to investigate whether the pain induced by spinal metastatic tumor and the narcotic and nonnarcotic drug use differed in spinal metastatic tumor patients before and after vertebroplasty. 2. Materials and methods 2.1. Patients In all study patients, at least several weeks of conservative therapy had failed, or they had been rendered nonambulatory by serious pain refractory to analgesics. Serious back pain was the sole indication for treatment in this study. No patient showed a tumor-related neurologic deficit. Mostly, intractable pain related to body movement limited the mobility of the patients. Preoperatively, an intensive diagnostic workup was performed in all patients, including spinal MRI for diction of tumor extension, localization, and infiltration of spinal canal and paravertebral tissue. If the primary cancer is unknown before vertebroplasty and is in a pathologic fracture suspicious for metastases, biopsy sample should be acquired intraoperatively. All these patients have tissue proof to be spinal metastatic tumors. The degree of metastatic infiltration of the vertebral body was analyzed using the semiquantitative visual grading of vertebral deformities devised by Genant et al [14]. Vertebral fracture result from metastasis was graded as normal (grade 0), mildly deformed (grade 1, with 20%-25% reduction in anterior, middle, and/or posterior height), moderately deformed (grade 2, with 25%40% reduction in anterior, middle, and/or posterior height), or severely deformed (grade 3, with 40% or greater reduction in any height). 2.2. Operative technique The procedure was usually performed under general anesthesia, but some patients accepted vertebroplasty under conscious sedation because of their clinical condition being poor and not suitable for general anesthesia. The patient must be lying in prone position for the duration of the intervention. Fluoroscopic C-arm guidance is essential throughout the procedure. A vertebral puncture is initiated by an approach specific to the involved vertebral level. A biopsy sample should be acquired if the primary cancer is unknown and is in a pathologic fracture suspicious for metastases. The PMMA is prepared and pushed into the vertebral body slowly and manually under continuous lateral fluoroscopic control to prevent leakage of cement into the spinal canal. If necessary,
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a second needle is inserted into the contralateral part of the vertebral body and the procedure is repeated. Two or 3 vertebrae may be treated during the same procedure. 2.3. Pain assessment The VAS was used to estimate the patients' pain perception before, 1 day, and 6 months after vertebroplasty. This scale with a range of 0 to 10 is a standard method in pain analysis, with 0 standard for no pain and 10 for intolerable pain. Visual analog scale is an objective evaluation of pain. Rolling/sitting ability and ambulation days were also used to evaluate the pain reduction of patients; the earlier the patient could sit more than 1 hour or walk, the more effective the pain reduction. There are many different kinds of analgesic with different effect of pain relief. It is really difficult to evaluate the pain reduction by analgesic. In 40 of 57 patients we enrolled, their analgesic was not changed before or after procedure. If a patient experienced significant pain relief after vertebroplasty, the analgesic was deleted gradually. To evaluate the reduction of analgesic drug use before and after vertebroplasty, we categorized the analgesic agent as narcotic and nonnarcotic agent and separately calculated the number of narcotic and nonnarcotic agents before and 48 hours after vertebroplasty. The reduction of analgesic agent in patients was evaluated. 2.4. Statistical analysis The VAS value before, 1 day, and 6 months after vertebroplasty were compared using the Wilcoxon signed rank nonparametric test for paired date. One-way analysis of variance was used to check for effects of different factors influencing the VAS change and analgesic use before and after vertebroplasty. Statistical significance was accepted for P ≤ .05. 3. Results 3.1. Characteristics of the patients Fifty-seven patients with 78 vertebrae (43 lumbar, 34 thoracic, and 1 cervical) were treated during the period from January 2002 to December 2006. Back pain was the sole indication for vertebroplasty in this study. Table 1 presents a summary of clinical data and the results for the 57 patients. Mostly, terrible pain related to body movement limited the mobility of the patients. Fifteen patients showed an infiltration of more than one vertebral body. In 4 of them, 3 vertebral bodies were affected, and in 1, 4 vertebral bodies were affected. The patients included 32 women and 25 men (age range, 40-86 years; mean age, 65.18 years). 3.2. Histology The primary tumor was histologically confirmed in all patients. Primary tumor sites were lungs, colon, urinary tract, gastrointestinal tract, and prostate in 33.3%, 15.8%, 14%,
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Table 1 Summary of data for the 57 patients with spinal metastatic tumor who underwent PMMA vertebroplasty Factor
Value/no. of patients
Mean age (range) (y) Sex ratio Mean preoperative VAS value (range) Mean postoperative VAS value (range) Mean 6-month VAS value (range) Location Cervical (%) Thoracic (%) Lumbar (%) Primary tumor Lung Colon Urinary tract Prostate Gastrointestinal Thyroid Breast Other Vertebral deformity grade (Genant) Grade 0 Grade 1 Grade 2 Grade 3 No. of affected vertebrae 1 2 3 4 Mean ambulatory day (mode) Mean walk day (mode) Complication Minor extravasation Major extravasation Postoperative hematoma
65.2 (40-86) 25 males/32 females 8.1 (6-10) 3.8 (1-8) 2.7 (0-9) 1 (0.01) 33 (42.31%) 44 (56.41%) 19 9 8 4 4 3 3 7 5 22 39 12 42 10 4 1 2.2 (0.5) 3.1 (1) 14 (17.9%) 3 (0.04%) 2 (0.08%)
7%, and 7% of patients, respectively. One patient had a C6 vertebral collapse due to a lymphoma in the vertebrae. Most patients received standard treatment of the primary tumor, including surgery and combined radiochemotherapy before vertebroplasty, and 9 patients had been diagnosed with spinal metastatic tumor before the primary tumor being diagnosed.
Fig. 1. The mean value of VAS was 8.1 ± 0.67 preoperatively and significantly decreased to 3.8 ± 1.9 one day after vertebroplasty. The mean VAS value 6 months after vertebroplasty was 2.8 ± 2.0 (P b .001). Significant reduction of VAS was demonstrated. VP indicates vertebroplasty; 1D, 1 day; 6M, 6 months.
tively, the amount of nonnarcotic and narcotic analgesic decreased to 1.35 ± 0.70 (P = .049) and 0.65 ± 0.53 (P N .05). The reduction of nonnarcotic agent reached statistical significance (Fig. 2). Seven patients were free of pain, and no analgesic was necessary. The amount of PMMA injected into vertebral body in our study ranged between 2 and 9 mL (mean, 5.16 ± 1.63). The amount of PMMA was not associated with pain reduction (P N .05). The grade (semiquantitative visual grading of vertebral deformities devised by Genant et al) of vertebral fracture result from metastasis was noticed associated with pain relief (VAS change) (P N .05). 3.4. Safety Extravasation of PMMA outside the vertebral margins was observed in 17 vertebrae (21.8%). Extravasation without neurologic deficit was defined as minor extravasation, and extravasation with neurologic deficit was defined as major extravasation. Fourteen (17.9%) vertebrae extravasation without neurologic deficit and 3 vertebral extravasation
3.3. Analgesic effect According to the VAS, the mean pain value preoperatively was 8.1 ± 0.67; 1 day after intervention, the VAS revealed a great reduction of pain. The mean pain value decreased significantly to 3.8 ± 1.9 (1-8, P b .015), and 6 months after vertebroplasty, the mean pain value was 2.8 ± 2.0 (0-9, P b .001) (Fig. 1). Most patients regained rolling and sitting functions more than 1 hour within 24 hours after vertebroplasty (mode, 0.5 days) and could walk within 48 hours after vertebroplasty (mode, 1 day). Preoperative analgesic drug use was reduced obviously 48 hours after vertebroplasty. The mean amounts of preoperative nonnarcotic analgesic and narcotic analgesic were 1.98 ± 1.4 and 1.19 ± 0.73, respectively. Postopera-
Fig. 2. Mean amounts of preoperative and postoperative analgesic. Both narcotic analgesic and nonnarcotic analgesic were decreased after vertebroplasty.
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Fig. 3. A 60-year-old male patient with a case of parotid malignant lymphoma with T10, T11, and L1 spinal metastatic tumors. Prevertebroplasty MRI and postvertebroplasty x-ray lateral view was illustrated. A: A T1-weighted MRI demonstrating low signal lesion at T10, T11, and L1 vertebrae. B: T1-weighted with enhancement MRI revealed high signal lesion at T10, T11, and L1 vertebrae. C: A lateral radiography showed that radiopaque cement is visible within the T10, T11, and L1 vertebrae.
(in 3 different patients) developed neurologic symptoms and needed decompression surgery. Two patients received laminectomy and internal fixation with transpedicle screw, and one patient receive laminectomy only. Two patients died because of postoperative sepsis: one was a patient who accepted laminectomy with transpedicle screw and the other accepted laminectomy only. Postoperative hematoma was observed in 2 patients, and 1 patient accepted surgical intervention to remove hematoma and recovered well after surgery. Two patients died during hospitalization because of medical disease: one was due to ischemic heart disease and the other was the case of lung cancer and died because of respiratory failure. Five patients died because of cancer progression during the follow-up period. During the follow-up period, no evidence of cancer spread to paraspinal muscle, subcutaneous tissue, and adjacent vertebrae. In our 57 patients, no new adjacent vertebral fracture was noticed. Fig. 3 shows examples of a parotid malignant lymphoma with T10, T11, and L2 pathologic vertebral fractures. Prevertebroplasty MRI and postvertebroplasty x-ray lateral view was demonstrated. As the
other 10 patients (total 11 patients in our 57 patients, 19.3%), metastatic spinal tumor was highly suspected, but there was no pathologic proof before vertebroplasty. Bone marrow (vertebrae) biopsy was performed during vertebroplasty, and all of these 11 patients have tissue proof for metastatic spinal tumor finally. After vertebroplasty, the intractable back pain was subsided and the primary tumor was diagnosed after a series of examinations. 4. Discussion Two different kinds of back pain are encountered in patients with metastatic spinal tumors: tumor related and mechanical. Tumor-related pain is predominantly nocturnal or occurs early morning, and it generally improves with activity during the day. This pain may be caused by inflammatory mediators or tumor stretching the periosteum of the vertebral body [5]. Mechanical pain results from a structural destruction of the spine, such as a pathologic compression fracture resulting in instability. This pain is movement related and may be exacerbated by increasing the axial load on the spine [3]. Pain likely initiates in
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intraosseous or periosteal nerves aggravated by motion at the fracture site [7,27]. In patients with malignancies, the infiltrating tumor destroys the integrity of the vertebrae, which is followed by vertebral collapse causing severe pain. Regardless of the primary tumor, vertebral compression fracture leads to disabling pain in all patients. This pain has been treated with analgesics, bed rest, and external bracing before the vertebroplasty was introduced. However, these treatments provided only little efficiency [9]. Treatment options available for metastatic spine tumors include radiation therapy, surgery, and chemotherapy. The appropriate treatment of an individual patient requires a multidisciplinary review input from a medical oncologist, internist, radiologist, radiation oncologist, neurologist, and surgeon. Surgery is indicated in selective groups of patients with metastatic tumors to spine [3]. Surgery in patients with metastatic spine tumor is high risk and is associated with a significant number of complications [15]. Results using laminectomy as initial therapy either alone or with adjuvant radiation yielded relatively poor outcome. Laminectomy does not provide exposure to resect lateral and anterior epidural or vertebral body tumor. In addition, resection of the posterior element without instrumentation often leads to progressive kyphosis and increased neurologic deficits. Vertebroplasty provides an immediate anterior stabilization of the vertebral column, which may avoid an anterior approach. The immediate analgesic effect of vertebroplasty can be explained by the so-called in situ immobilization of vertebral body fracture. Pathophysiologically, the cement is inserted into the bone and stabilizes the bone immediately [2,22]. The internal stabilization provided by vertebroplasty probably prevents micromotion and subsequent pain and provides a stable environment for healing [6]. The best results are seen in patients who present a severe, focal, and mechanical back pain related to a neoplastic vertebral collapse without epidural involvement [27,29]. Winking et al [29] reported that 19 (86%) of 22 patients had a significant pain reduction. Vertebroplasty was highly beneficial for patients with pain related to local instability of the spine. Weill et al [30] reveled a clear improvement of pain in 24 (73%) of 33 procedures in a series of patients treated for metastatic lesion by vertebroplasty. Yang et al [28] collected 110 patients with metastatic spinal tumor and divided them into 55 patients in the treatment group and 55 patients in the control group. The treatment group was treated by PVP. The statistics showed a significant difference between the 2 groups, specifically, changes in the quality of life and evaluation of bone pain (P b .05, t1 = 2.74, t2 = 9.02). Vertebroplasty can effectively alleviate pain of metastatic spinal tumors in patients [25]. In this study, a total of 57 patients (78 vertebrae) with intractable back pain due to osteolytic metastasis of various primary tumors were treated with vertebroplasty. The mean pain value preoperatively was 8.1 ± 0.67; 1 day after intervention, the VAS revealed a great reduction of pain. The
mean pain value decreased significantly to 3.8 ± 1.9 (1-8, P b .015), and 6 months after vertebroplasty, the mean pain value was 2.8 ± 2.0 (0-9, P b .001). In our study, preprocedural pain, measured by the VAS, was 8.13, decreasing to 3.78 one day after the procedure and 2.77 six months after the procedure. A significant reduction of pain could be achieved, and the total amount of analgesic was also reduced. Alvarez et al [3] reported results of PVP with PMMA of vertebral metastases evaluated by a retrospective review of a consecutive series of 21 patients; the patients' preprocedural pain, measured by VAS, was 9.1, decreasing to 3.2 after the procedure and 2.8 at the last follow-up visit. Analgesic use was restricted in 40 of our 57 patients, and postoperative analgesics were not changed before or after vertebroplasty. We only deleted or decreased dose of analgesics after vertebroplasty when significant reduction of pain was reached. Preoperative analgesic drug use was reduced obviously 48 hours after vertebroplasty. The mean amounts of preoperative nonnarcotic analgesic and narcotic analgesic were 1.98 ± 1.4 and 1.19 ± 0.73, respectively. Postoperatively, the amounts of nonnarcotic and narcotic analgesic decrease to 1.35 ± 0.70 (P = .049, b.05) and 0.65 ± 0.53 (P N .05). The reduction of nonnarcotic agent reached statistical significance. Seven patients were free of pain, and no analgesic was necessary for them. Sixty-five percent to 76% of the patients in all studies got prompt relief of pain and experienced persisted pain relief. Both conventional fractionated and nonfractionated radiotherapy are associated with similar rates of pain control. Pain relief after radiotherapy, however, is often delayed 10 to 20 days, and there was minimal vertebral strengthening of the vertebral column, which may limit painful vertebral collapse [7,29]. As defined by Panjabi et al [24], spinal stability is the degree of motion that prevents pain, neurologic deficit, and abnormal angulation. Instability caused by tumor appears to be different from that associated with traumatic injury. Current classification proposals have divided each vertebra into 2, 3, or 6 columns but have failed to predict accurately future neuroimaging and/or clinical confirmation of progression consistent with instability [10,25]. The goal of PMMA injection is to provide adequate support for the anterior column [21]. Vertebral stiffness recovery after vertebroplasty is strongly influenced by the volume fraction of the implanted cement. Only a small amount of bone cement (average, 14% fill or 3.5 mL) is necessary to restore stiffness of the damaged vertebral body [8,12,15]. In our study, the average amount of implanted bone cement was 5.16 ± 1.63 mL (range, 2-9.0 mL), enough to recover vertebral stiffness. Review of multiple series shows complication rate from surgery for metastatic spinal tumor ranging from 10% to 52% [17,20]. Complications include medical issue such as deep venous thrombosis, myocardial infarct, and pneumonia. Surgical complication included failed fixation requiring revision and postoperative hematoma. Wound dehiscence and infection are complications seen in up to 15% of cases [7,20]. In our study, a total of 57 patients with
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spinal metastatic tumor were treated with PVP; 3 patients had bone cement extravasation with neurologic deficit and needed further surgical intervention. One patient experienced postprocedural subcutaneous hematoma and need operation to remove hematoma. Compared with previous surgical treatment of spinal metastatic lesion, this new minimally invasive technique provides immediate strengthening of the anterior column, which may limit painful vertebral body collapse and achieve significant pain relief with minor and infrequent complications. 5. Conclusion Because of the highly individualized nature of spinal metastatic tumors, a multidisciplinary approach is recommended. Surgery in these patients is high risk and is associated with a significant number of complications and are more prevalent in patients who received prior radiotherapy. Percutaneous vertebroplasty is a minimally invasive radiologically guided procedure in which bone cement is injected into structurally weakened or destructed vertebrae to achieve additional biomechanical stability. Increased mobility and pain reduction lead to improvement of life quality. As a treatment option for patients with malignant destruction of the vertebral column, it provides fast and effective pain relief and significant reduction of nonnarcotic analgesic use. Immediate and effective pain relief after treatment restores the patients' quality of life and shortens the hospitalization days. References [1] Aaron AD. The management of cancer metastatic to bone. JAMA 1994;272:1206-9. [2] Ahn H, Mousavi P, Roth S, et al. Stability of the metastatic spine pre and post vertebroplasty. J Spinal Disord Tech 2006;19:178-82. [3] Alvarez L, Perez-Higueras A, Quinones D, et al. Vertebroplasty in the treatment of vertebral tumors: postprocedural outcome and quality of life. Eur Spine J 2003;12:356-60. [4] Barr JD, Barr MS, Lemley TJ, et al. Percutaneous vertebroplasty for pain relief and spinal stabilization. Spine 2000;25:923-8. [5] Barron KD, Hirano A, Araki S, et al. Experiences with metastatic neoplasms involving the spinal cord. Neurology 1959;9:91–106. [6] Belkoff SM, Mathis JM, Jasper LE, et al. The biomechanics of vertebroplasty. The effect of cement volume on mechanical behavior. Spine 2001;26:1537-41. [7] Bilsky MH, Lis E, Raizer J, et al. The diagnosis and treatment of metastatic spinal tumor. Oncologist 1999;4:459-69. [8] Chen HH, Wang WK, Li KC, et al. Biomechanical effects of the body augmenter for reconstruction of the vertebral body. Spine 2004;29: E382-7. [9] Cortet B, Cotten A, Boutry N, et al. Percutaneous vertebroplasty in the treatment of osteoporotic vertebral compression fractures: an open prospective study. J Rheumatol 1999;26:2222-8. [10] Denis F. The three column spine and its significance in the classification of acute thoracolumbar spinal injuries. Spine 1983;8: 817-31. [11] Deramond H, Depriester C, Galibert P, et al. Percutaneous vertebroplasty with polymethylmethacrylate. Technique, indications, and results. Radiol Clin North Am 1998;36:533-46.
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[12] Farooq N, Park JC, Pollintine P, et al. Can vertebroplasty restore normal load-bearing to fractured vertebrae? Spine 2005;30:1723-30. [13] Gangi A, Kastler BA, Dietemann JL. Percutaneous vertebroplasty guided by a combination of CT and fluoroscopy. AJNR Am J Neuroradiol 1994;15:83-6. [14] Genant HK, Wu CY, van Kuijk C, et al. Vertebral fracture assessment using a semiquantitative technique. J Bone Miner Res 1993;8: 1137-48. [15] Ghogawala Z, Mansfield FL, Borges LF. Spinal radiation before surgical decompression adversely affects outcomes of surgery for symptomatic metastatic spinal cord compression. Spine 2001;26:818-24. [16] Gokaslan ZL, York JE, Walsh GL, et al. Transthoracic vertebrectomy for metastatic spinal tumors. J Neurosurg 1998;89:599-609. [17] Harringon K. Anterior decompression and stabilization of the spine as a treatment for vertebral body collapse and spinal cord compression for metastatic malignancy. Clin Orthop 1988;233:177-97. [18] Jensen ME, Evans AJ, Mathis JM, et al. Percutaneous polymethylmethacrylate vertebroplasty in the treatment of osteoporotic vertebral body compression fractures: technical aspects. AJNR Am J Neuroradiol 1997;18:1897-904. [19] Jensen ME, Kallmes DE. Percutaneous vertebroplasty in the treatment of malignant spine disease. Cancer J 2002;8:194-206. [20] Klekamp J, Samii H. Surgical results for spinal metastases. Acta Neurochir(Wien) 1998;140:957-67. [21] Kostuik JP, Errico TJ, Gleason TF, et al. Spinal stabilization of vertebral column tumors. Spine 1988;13:250-6. [22] Liebschner MA, Rosenberg WS, Keaveny TM. Effects of bone cement volume and distribution on vertebral stiffness after vertebroplasty. Spine 2001;26:1547-54. [23] Nicola N, Lins E. Vertebral hemangioma: retrograde embolizationstabilization with methyl methacrylate. Surg Neurol 1987;27:481-6. [24] Panjabi MM, Thibodeau LL, Crisco JJ, et al. What constitutes spinal instability? Clin Neurosurg 1988;34:313-39. [25] Schiff D, O'Neill BP, Suman VJ. Spinal epidural metastasis as the initial manifestation of malignancy: clinical features and diagnostic approach. Neurology 1997;49:452-6. [26] Schiff D, O'Neill BP, Wang CH, et al. Neuroimaging and treatment implications of patients with multiple epidural spinal metastases. Cancer 1998;83:1593-601. [27] Siddall PJ, Cousins MJ. Spinal pain mechanisms. Spine 1997;22:98-104. [28] Yang Z, Xu J, Jin C, et al. Clinical study of the treatment of patients with a metastatic spinal tumor by percutaneous vertebroplasty under the guidance of DSA. Chin J Clin Oncol 2005;2:870-5. [29] Winking M, Stahl JP, Oertel M, et al. Polymethylmethacrylatevertebroplasty in patients with malignant vertebral destruction of thoracic and lumbar spine. German Med Sci 2003;1:Doc08. [30] Weill A, Chiras J, Simon JM, et al. Spinal metastases: indications for and results of percutaneous injection of acrylic surgical cement. Radiology 1996;199:241-7.
Commentary The skeletal system is the third most common site of cancer metastasis after lung and liver. Several factors favor bone metastasis, such as high blood flow in red marrow and many growth factors containing in bone—both of which create a fertile microenvironment for metastasis. The spinal vertebrae are notoriously prone to metastasis. Symptoms of night pain and rest pain should prompt a study of malignant etiology. Spinal metastases usually indicate a poor prognosis. The major complaint of the patients is pain, which is usually severe and often intractable. These patients need multidisciplinary care
Surgical Neurology 70 (2008) S1:78 – S1:84 www.surgicalneurology-online.com
Pain
Percutaneous polymethylmethacrylate vertebroplasty in the treatment of pain induced by metastatic spine tumor Yuan-Yun Tseng, MD a , Yang-Lan Lo, MD a , Lih-Huei Chen, MD b , Po-Liang Lai, MD b , Shun-Tai Yang, MD a,⁎ a
b
Department of Neurosurgery, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan, 333, ROC Department of Orthopaedic Surgery, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan, 333, ROC Received 26 May 2008; accepted 29 August 2008
Abstract
Background: Metastases to the spine are a common problem in the large oncology center and represent a challenging problem in oncology practice. Patients with osteolytic metastases often experience intractable local and/or radicular pain. Therapeutic intervention can alleviate pain, preserve or improve neurologic function, achieve mechanical stability, and improve quality of life. Percutaneous polymethylmethacrylate vertebroplasty is an effective and relatively easy method of relieving patients' pain. Method: Between January 2002 and December 2006, 57 patients (78 vertebrae) with spinal metastatic tumor treated with PMMA vertebroplasty were enrolled in this study. The main indication for treatment was pain. Result: The mean value of VAS was 8.1 ± 0.67 preoperatively, and it significantly decreased to 3.8 ± 1.9 (1-8, P b .015) 1 day after vertebroplasty. The mean VAS value 6 months after vertebroplasty was 2.8 ± 2.0 (P b .001). The mean amounts of preoperative nonnarcotic analgesic and narcotic analgesic were 1.98 ± 1.4 and 1.19 ± 0.73, respectively. Postoperatively, the mean amounts of nonnarcotic and narcotic analgesic decreased to 1.35 ± 0.70 (P b .05) and 0.65 ± 0.53 (P b .05). A statistically significant reduction of nonnarcotic analgesic use was noticed in our study. Conclusions: Percutaneous vertebroplasty is a minimally invasive procedure that offers a remarkable advantage of effective and immediate pain relief with few complications. © 2008 Elsevier Inc. All rights reserved.
Keywords:
Vertebroplasty; Spinal metastatic tumor; Spinal instability; Pain
1. Introduction The skeletal system is the third most common site of metastases, with the spine being the most common site of skeletal metastasis [1]. Between 5% and 10% of all cancer patients develop spinal metastases during the course of their disease. Serious back pain, the most common presenting symptom in patients with metastatic spinal tumor, frequently Abbreviations: MRI, magnetic resonance imaging; PMMA, percutaneous polymethylmethacrylate; PVP, percutaneous vertebroplasty; VAS, visual analog scale. ⁎ Corresponding author. Tel.: +886 3 328 1200x2119; fax: +886 3 328 5818. E-mail address: [email protected] (S.-T. Yang). 0090-3019/$ – see front matter © 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.surneu.2008.08.078
precedes the development of other neurologic symptoms [5]. All physicians should recognize that spinal cord compression occurs not uncommonly as the initial manifestation of malignancy, and not only in the setting of established malignancy [25,16]. A correct and complete diagnosis of neurologic symptoms is necessary to give appropriate therapy. Magnetic resonance imaging has revolutionized assessment of metastatic spinal tumor. Magnetic resonance imaging is the most sensitive and specific modality for imaging spinal metastases; screening images of the entire spine reveal bone, epidural, and paraspinal tumors [26]. Percutaneous transpedicular vertebroplasty is a procedure in which PMMA bone cement is injected into a vertebral
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body. Vertebroplasty was developed in France in the late 1980s for the treatment of vertebral angiomas [11]. Initial success with this interventional procedure in hemangiomas has led to its use in the treatment of osteoporotic and osteolytic lesions [4,11,23]. Vertebroplasty is a minimally invasive procedure resulting in prompt pain relief and has a low complication rate [13,18,19]. The benefits of vertebroplasty for treatment of neoplastic disease were reported in a prior series. The aim of this retrospective observational study was to investigate whether the pain induced by spinal metastatic tumor and the narcotic and nonnarcotic drug use differed in spinal metastatic tumor patients before and after vertebroplasty. 2. Materials and methods 2.1. Patients In all study patients, at least several weeks of conservative therapy had failed, or they had been rendered nonambulatory by serious pain refractory to analgesics. Serious back pain was the sole indication for treatment in this study. No patient showed a tumor-related neurologic deficit. Mostly, intractable pain related to body movement limited the mobility of the patients. Preoperatively, an intensive diagnostic workup was performed in all patients, including spinal MRI for diction of tumor extension, localization, and infiltration of spinal canal and paravertebral tissue. If the primary cancer is unknown before vertebroplasty and is in a pathologic fracture suspicious for metastases, biopsy sample should be acquired intraoperatively. All these patients have tissue proof to be spinal metastatic tumors. The degree of metastatic infiltration of the vertebral body was analyzed using the semiquantitative visual grading of vertebral deformities devised by Genant et al [14]. Vertebral fracture result from metastasis was graded as normal (grade 0), mildly deformed (grade 1, with 20%-25% reduction in anterior, middle, and/or posterior height), moderately deformed (grade 2, with 25%40% reduction in anterior, middle, and/or posterior height), or severely deformed (grade 3, with 40% or greater reduction in any height). 2.2. Operative technique The procedure was usually performed under general anesthesia, but some patients accepted vertebroplasty under conscious sedation because of their clinical condition being poor and not suitable for general anesthesia. The patient must be lying in prone position for the duration of the intervention. Fluoroscopic C-arm guidance is essential throughout the procedure. A vertebral puncture is initiated by an approach specific to the involved vertebral level. A biopsy sample should be acquired if the primary cancer is unknown and is in a pathologic fracture suspicious for metastases. The PMMA is prepared and pushed into the vertebral body slowly and manually under continuous lateral fluoroscopic control to prevent leakage of cement into the spinal canal. If necessary,
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a second needle is inserted into the contralateral part of the vertebral body and the procedure is repeated. Two or 3 vertebrae may be treated during the same procedure. 2.3. Pain assessment The VAS was used to estimate the patients' pain perception before, 1 day, and 6 months after vertebroplasty. This scale with a range of 0 to 10 is a standard method in pain analysis, with 0 standard for no pain and 10 for intolerable pain. Visual analog scale is an objective evaluation of pain. Rolling/sitting ability and ambulation days were also used to evaluate the pain reduction of patients; the earlier the patient could sit more than 1 hour or walk, the more effective the pain reduction. There are many different kinds of analgesic with different effect of pain relief. It is really difficult to evaluate the pain reduction by analgesic. In 40 of 57 patients we enrolled, their analgesic was not changed before or after procedure. If a patient experienced significant pain relief after vertebroplasty, the analgesic was deleted gradually. To evaluate the reduction of analgesic drug use before and after vertebroplasty, we categorized the analgesic agent as narcotic and nonnarcotic agent and separately calculated the number of narcotic and nonnarcotic agents before and 48 hours after vertebroplasty. The reduction of analgesic agent in patients was evaluated. 2.4. Statistical analysis The VAS value before, 1 day, and 6 months after vertebroplasty were compared using the Wilcoxon signed rank nonparametric test for paired date. One-way analysis of variance was used to check for effects of different factors influencing the VAS change and analgesic use before and after vertebroplasty. Statistical significance was accepted for P ≤ .05. 3. Results 3.1. Characteristics of the patients Fifty-seven patients with 78 vertebrae (43 lumbar, 34 thoracic, and 1 cervical) were treated during the period from January 2002 to December 2006. Back pain was the sole indication for vertebroplasty in this study. Table 1 presents a summary of clinical data and the results for the 57 patients. Mostly, terrible pain related to body movement limited the mobility of the patients. Fifteen patients showed an infiltration of more than one vertebral body. In 4 of them, 3 vertebral bodies were affected, and in 1, 4 vertebral bodies were affected. The patients included 32 women and 25 men (age range, 40-86 years; mean age, 65.18 years). 3.2. Histology The primary tumor was histologically confirmed in all patients. Primary tumor sites were lungs, colon, urinary tract, gastrointestinal tract, and prostate in 33.3%, 15.8%, 14%,
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Table 1 Summary of data for the 57 patients with spinal metastatic tumor who underwent PMMA vertebroplasty Factor
Value/no. of patients
Mean age (range) (y) Sex ratio Mean preoperative VAS value (range) Mean postoperative VAS value (range) Mean 6-month VAS value (range) Location Cervical (%) Thoracic (%) Lumbar (%) Primary tumor Lung Colon Urinary tract Prostate Gastrointestinal Thyroid Breast Other Vertebral deformity grade (Genant) Grade 0 Grade 1 Grade 2 Grade 3 No. of affected vertebrae 1 2 3 4 Mean ambulatory day (mode) Mean walk day (mode) Complication Minor extravasation Major extravasation Postoperative hematoma
65.2 (40-86) 25 males/32 females 8.1 (6-10) 3.8 (1-8) 2.7 (0-9) 1 (0.01) 33 (42.31%) 44 (56.41%) 19 9 8 4 4 3 3 7 5 22 39 12 42 10 4 1 2.2 (0.5) 3.1 (1) 14 (17.9%) 3 (0.04%) 2 (0.08%)
7%, and 7% of patients, respectively. One patient had a C6 vertebral collapse due to a lymphoma in the vertebrae. Most patients received standard treatment of the primary tumor, including surgery and combined radiochemotherapy before vertebroplasty, and 9 patients had been diagnosed with spinal metastatic tumor before the primary tumor being diagnosed.
Fig. 1. The mean value of VAS was 8.1 ± 0.67 preoperatively and significantly decreased to 3.8 ± 1.9 one day after vertebroplasty. The mean VAS value 6 months after vertebroplasty was 2.8 ± 2.0 (P b .001). Significant reduction of VAS was demonstrated. VP indicates vertebroplasty; 1D, 1 day; 6M, 6 months.
tively, the amount of nonnarcotic and narcotic analgesic decreased to 1.35 ± 0.70 (P = .049) and 0.65 ± 0.53 (P N .05). The reduction of nonnarcotic agent reached statistical significance (Fig. 2). Seven patients were free of pain, and no analgesic was necessary. The amount of PMMA injected into vertebral body in our study ranged between 2 and 9 mL (mean, 5.16 ± 1.63). The amount of PMMA was not associated with pain reduction (P N .05). The grade (semiquantitative visual grading of vertebral deformities devised by Genant et al) of vertebral fracture result from metastasis was noticed associated with pain relief (VAS change) (P N .05). 3.4. Safety Extravasation of PMMA outside the vertebral margins was observed in 17 vertebrae (21.8%). Extravasation without neurologic deficit was defined as minor extravasation, and extravasation with neurologic deficit was defined as major extravasation. Fourteen (17.9%) vertebrae extravasation without neurologic deficit and 3 vertebral extravasation
3.3. Analgesic effect According to the VAS, the mean pain value preoperatively was 8.1 ± 0.67; 1 day after intervention, the VAS revealed a great reduction of pain. The mean pain value decreased significantly to 3.8 ± 1.9 (1-8, P b .015), and 6 months after vertebroplasty, the mean pain value was 2.8 ± 2.0 (0-9, P b .001) (Fig. 1). Most patients regained rolling and sitting functions more than 1 hour within 24 hours after vertebroplasty (mode, 0.5 days) and could walk within 48 hours after vertebroplasty (mode, 1 day). Preoperative analgesic drug use was reduced obviously 48 hours after vertebroplasty. The mean amounts of preoperative nonnarcotic analgesic and narcotic analgesic were 1.98 ± 1.4 and 1.19 ± 0.73, respectively. Postopera-
Fig. 2. Mean amounts of preoperative and postoperative analgesic. Both narcotic analgesic and nonnarcotic analgesic were decreased after vertebroplasty.
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Fig. 3. A 60-year-old male patient with a case of parotid malignant lymphoma with T10, T11, and L1 spinal metastatic tumors. Prevertebroplasty MRI and postvertebroplasty x-ray lateral view was illustrated. A: A T1-weighted MRI demonstrating low signal lesion at T10, T11, and L1 vertebrae. B: T1-weighted with enhancement MRI revealed high signal lesion at T10, T11, and L1 vertebrae. C: A lateral radiography showed that radiopaque cement is visible within the T10, T11, and L1 vertebrae.
(in 3 different patients) developed neurologic symptoms and needed decompression surgery. Two patients received laminectomy and internal fixation with transpedicle screw, and one patient receive laminectomy only. Two patients died because of postoperative sepsis: one was a patient who accepted laminectomy with transpedicle screw and the other accepted laminectomy only. Postoperative hematoma was observed in 2 patients, and 1 patient accepted surgical intervention to remove hematoma and recovered well after surgery. Two patients died during hospitalization because of medical disease: one was due to ischemic heart disease and the other was the case of lung cancer and died because of respiratory failure. Five patients died because of cancer progression during the follow-up period. During the follow-up period, no evidence of cancer spread to paraspinal muscle, subcutaneous tissue, and adjacent vertebrae. In our 57 patients, no new adjacent vertebral fracture was noticed. Fig. 3 shows examples of a parotid malignant lymphoma with T10, T11, and L2 pathologic vertebral fractures. Prevertebroplasty MRI and postvertebroplasty x-ray lateral view was demonstrated. As the
other 10 patients (total 11 patients in our 57 patients, 19.3%), metastatic spinal tumor was highly suspected, but there was no pathologic proof before vertebroplasty. Bone marrow (vertebrae) biopsy was performed during vertebroplasty, and all of these 11 patients have tissue proof for metastatic spinal tumor finally. After vertebroplasty, the intractable back pain was subsided and the primary tumor was diagnosed after a series of examinations. 4. Discussion Two different kinds of back pain are encountered in patients with metastatic spinal tumors: tumor related and mechanical. Tumor-related pain is predominantly nocturnal or occurs early morning, and it generally improves with activity during the day. This pain may be caused by inflammatory mediators or tumor stretching the periosteum of the vertebral body [5]. Mechanical pain results from a structural destruction of the spine, such as a pathologic compression fracture resulting in instability. This pain is movement related and may be exacerbated by increasing the axial load on the spine [3]. Pain likely initiates in
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intraosseous or periosteal nerves aggravated by motion at the fracture site [7,27]. In patients with malignancies, the infiltrating tumor destroys the integrity of the vertebrae, which is followed by vertebral collapse causing severe pain. Regardless of the primary tumor, vertebral compression fracture leads to disabling pain in all patients. This pain has been treated with analgesics, bed rest, and external bracing before the vertebroplasty was introduced. However, these treatments provided only little efficiency [9]. Treatment options available for metastatic spine tumors include radiation therapy, surgery, and chemotherapy. The appropriate treatment of an individual patient requires a multidisciplinary review input from a medical oncologist, internist, radiologist, radiation oncologist, neurologist, and surgeon. Surgery is indicated in selective groups of patients with metastatic tumors to spine [3]. Surgery in patients with metastatic spine tumor is high risk and is associated with a significant number of complications [15]. Results using laminectomy as initial therapy either alone or with adjuvant radiation yielded relatively poor outcome. Laminectomy does not provide exposure to resect lateral and anterior epidural or vertebral body tumor. In addition, resection of the posterior element without instrumentation often leads to progressive kyphosis and increased neurologic deficits. Vertebroplasty provides an immediate anterior stabilization of the vertebral column, which may avoid an anterior approach. The immediate analgesic effect of vertebroplasty can be explained by the so-called in situ immobilization of vertebral body fracture. Pathophysiologically, the cement is inserted into the bone and stabilizes the bone immediately [2,22]. The internal stabilization provided by vertebroplasty probably prevents micromotion and subsequent pain and provides a stable environment for healing [6]. The best results are seen in patients who present a severe, focal, and mechanical back pain related to a neoplastic vertebral collapse without epidural involvement [27,29]. Winking et al [29] reported that 19 (86%) of 22 patients had a significant pain reduction. Vertebroplasty was highly beneficial for patients with pain related to local instability of the spine. Weill et al [30] reveled a clear improvement of pain in 24 (73%) of 33 procedures in a series of patients treated for metastatic lesion by vertebroplasty. Yang et al [28] collected 110 patients with metastatic spinal tumor and divided them into 55 patients in the treatment group and 55 patients in the control group. The treatment group was treated by PVP. The statistics showed a significant difference between the 2 groups, specifically, changes in the quality of life and evaluation of bone pain (P b .05, t1 = 2.74, t2 = 9.02). Vertebroplasty can effectively alleviate pain of metastatic spinal tumors in patients [25]. In this study, a total of 57 patients (78 vertebrae) with intractable back pain due to osteolytic metastasis of various primary tumors were treated with vertebroplasty. The mean pain value preoperatively was 8.1 ± 0.67; 1 day after intervention, the VAS revealed a great reduction of pain. The
mean pain value decreased significantly to 3.8 ± 1.9 (1-8, P b .015), and 6 months after vertebroplasty, the mean pain value was 2.8 ± 2.0 (0-9, P b .001). In our study, preprocedural pain, measured by the VAS, was 8.13, decreasing to 3.78 one day after the procedure and 2.77 six months after the procedure. A significant reduction of pain could be achieved, and the total amount of analgesic was also reduced. Alvarez et al [3] reported results of PVP with PMMA of vertebral metastases evaluated by a retrospective review of a consecutive series of 21 patients; the patients' preprocedural pain, measured by VAS, was 9.1, decreasing to 3.2 after the procedure and 2.8 at the last follow-up visit. Analgesic use was restricted in 40 of our 57 patients, and postoperative analgesics were not changed before or after vertebroplasty. We only deleted or decreased dose of analgesics after vertebroplasty when significant reduction of pain was reached. Preoperative analgesic drug use was reduced obviously 48 hours after vertebroplasty. The mean amounts of preoperative nonnarcotic analgesic and narcotic analgesic were 1.98 ± 1.4 and 1.19 ± 0.73, respectively. Postoperatively, the amounts of nonnarcotic and narcotic analgesic decrease to 1.35 ± 0.70 (P = .049, b.05) and 0.65 ± 0.53 (P N .05). The reduction of nonnarcotic agent reached statistical significance. Seven patients were free of pain, and no analgesic was necessary for them. Sixty-five percent to 76% of the patients in all studies got prompt relief of pain and experienced persisted pain relief. Both conventional fractionated and nonfractionated radiotherapy are associated with similar rates of pain control. Pain relief after radiotherapy, however, is often delayed 10 to 20 days, and there was minimal vertebral strengthening of the vertebral column, which may limit painful vertebral collapse [7,29]. As defined by Panjabi et al [24], spinal stability is the degree of motion that prevents pain, neurologic deficit, and abnormal angulation. Instability caused by tumor appears to be different from that associated with traumatic injury. Current classification proposals have divided each vertebra into 2, 3, or 6 columns but have failed to predict accurately future neuroimaging and/or clinical confirmation of progression consistent with instability [10,25]. The goal of PMMA injection is to provide adequate support for the anterior column [21]. Vertebral stiffness recovery after vertebroplasty is strongly influenced by the volume fraction of the implanted cement. Only a small amount of bone cement (average, 14% fill or 3.5 mL) is necessary to restore stiffness of the damaged vertebral body [8,12,15]. In our study, the average amount of implanted bone cement was 5.16 ± 1.63 mL (range, 2-9.0 mL), enough to recover vertebral stiffness. Review of multiple series shows complication rate from surgery for metastatic spinal tumor ranging from 10% to 52% [17,20]. Complications include medical issue such as deep venous thrombosis, myocardial infarct, and pneumonia. Surgical complication included failed fixation requiring revision and postoperative hematoma. Wound dehiscence and infection are complications seen in up to 15% of cases [7,20]. In our study, a total of 57 patients with
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spinal metastatic tumor were treated with PVP; 3 patients had bone cement extravasation with neurologic deficit and needed further surgical intervention. One patient experienced postprocedural subcutaneous hematoma and need operation to remove hematoma. Compared with previous surgical treatment of spinal metastatic lesion, this new minimally invasive technique provides immediate strengthening of the anterior column, which may limit painful vertebral body collapse and achieve significant pain relief with minor and infrequent complications. 5. Conclusion Because of the highly individualized nature of spinal metastatic tumors, a multidisciplinary approach is recommended. Surgery in these patients is high risk and is associated with a significant number of complications and are more prevalent in patients who received prior radiotherapy. Percutaneous vertebroplasty is a minimally invasive radiologically guided procedure in which bone cement is injected into structurally weakened or destructed vertebrae to achieve additional biomechanical stability. Increased mobility and pain reduction lead to improvement of life quality. As a treatment option for patients with malignant destruction of the vertebral column, it provides fast and effective pain relief and significant reduction of nonnarcotic analgesic use. Immediate and effective pain relief after treatment restores the patients' quality of life and shortens the hospitalization days. References [1] Aaron AD. The management of cancer metastatic to bone. JAMA 1994;272:1206-9. [2] Ahn H, Mousavi P, Roth S, et al. Stability of the metastatic spine pre and post vertebroplasty. J Spinal Disord Tech 2006;19:178-82. [3] Alvarez L, Perez-Higueras A, Quinones D, et al. Vertebroplasty in the treatment of vertebral tumors: postprocedural outcome and quality of life. Eur Spine J 2003;12:356-60. [4] Barr JD, Barr MS, Lemley TJ, et al. Percutaneous vertebroplasty for pain relief and spinal stabilization. Spine 2000;25:923-8. [5] Barron KD, Hirano A, Araki S, et al. Experiences with metastatic neoplasms involving the spinal cord. Neurology 1959;9:91–106. [6] Belkoff SM, Mathis JM, Jasper LE, et al. The biomechanics of vertebroplasty. The effect of cement volume on mechanical behavior. Spine 2001;26:1537-41. [7] Bilsky MH, Lis E, Raizer J, et al. The diagnosis and treatment of metastatic spinal tumor. Oncologist 1999;4:459-69. [8] Chen HH, Wang WK, Li KC, et al. Biomechanical effects of the body augmenter for reconstruction of the vertebral body. Spine 2004;29: E382-7. [9] Cortet B, Cotten A, Boutry N, et al. Percutaneous vertebroplasty in the treatment of osteoporotic vertebral compression fractures: an open prospective study. J Rheumatol 1999;26:2222-8. [10] Denis F. The three column spine and its significance in the classification of acute thoracolumbar spinal injuries. Spine 1983;8: 817-31. [11] Deramond H, Depriester C, Galibert P, et al. Percutaneous vertebroplasty with polymethylmethacrylate. Technique, indications, and results. Radiol Clin North Am 1998;36:533-46.
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[12] Farooq N, Park JC, Pollintine P, et al. Can vertebroplasty restore normal load-bearing to fractured vertebrae? Spine 2005;30:1723-30. [13] Gangi A, Kastler BA, Dietemann JL. Percutaneous vertebroplasty guided by a combination of CT and fluoroscopy. AJNR Am J Neuroradiol 1994;15:83-6. [14] Genant HK, Wu CY, van Kuijk C, et al. Vertebral fracture assessment using a semiquantitative technique. J Bone Miner Res 1993;8: 1137-48. [15] Ghogawala Z, Mansfield FL, Borges LF. Spinal radiation before surgical decompression adversely affects outcomes of surgery for symptomatic metastatic spinal cord compression. Spine 2001;26:818-24. [16] Gokaslan ZL, York JE, Walsh GL, et al. Transthoracic vertebrectomy for metastatic spinal tumors. J Neurosurg 1998;89:599-609. [17] Harringon K. Anterior decompression and stabilization of the spine as a treatment for vertebral body collapse and spinal cord compression for metastatic malignancy. Clin Orthop 1988;233:177-97. [18] Jensen ME, Evans AJ, Mathis JM, et al. Percutaneous polymethylmethacrylate vertebroplasty in the treatment of osteoporotic vertebral body compression fractures: technical aspects. AJNR Am J Neuroradiol 1997;18:1897-904. [19] Jensen ME, Kallmes DE. Percutaneous vertebroplasty in the treatment of malignant spine disease. Cancer J 2002;8:194-206. [20] Klekamp J, Samii H. Surgical results for spinal metastases. Acta Neurochir(Wien) 1998;140:957-67. [21] Kostuik JP, Errico TJ, Gleason TF, et al. Spinal stabilization of vertebral column tumors. Spine 1988;13:250-6. [22] Liebschner MA, Rosenberg WS, Keaveny TM. Effects of bone cement volume and distribution on vertebral stiffness after vertebroplasty. Spine 2001;26:1547-54. [23] Nicola N, Lins E. Vertebral hemangioma: retrograde embolizationstabilization with methyl methacrylate. Surg Neurol 1987;27:481-6. [24] Panjabi MM, Thibodeau LL, Crisco JJ, et al. What constitutes spinal instability? Clin Neurosurg 1988;34:313-39. [25] Schiff D, O'Neill BP, Suman VJ. Spinal epidural metastasis as the initial manifestation of malignancy: clinical features and diagnostic approach. Neurology 1997;49:452-6. [26] Schiff D, O'Neill BP, Wang CH, et al. Neuroimaging and treatment implications of patients with multiple epidural spinal metastases. Cancer 1998;83:1593-601. [27] Siddall PJ, Cousins MJ. Spinal pain mechanisms. Spine 1997;22:98-104. [28] Yang Z, Xu J, Jin C, et al. Clinical study of the treatment of patients with a metastatic spinal tumor by percutaneous vertebroplasty under the guidance of DSA. Chin J Clin Oncol 2005;2:870-5. [29] Winking M, Stahl JP, Oertel M, et al. Polymethylmethacrylatevertebroplasty in patients with malignant vertebral destruction of thoracic and lumbar spine. German Med Sci 2003;1:Doc08. [30] Weill A, Chiras J, Simon JM, et al. Spinal metastases: indications for and results of percutaneous injection of acrylic surgical cement. Radiology 1996;199:241-7.
Commentary The skeletal system is the third most common site of cancer metastasis after lung and liver. Several factors favor bone metastasis, such as high blood flow in red marrow and many growth factors containing in bone—both of which create a fertile microenvironment for metastasis. The spinal vertebrae are notoriously prone to metastasis. Symptoms of night pain and rest pain should prompt a study of malignant etiology. Spinal metastases usually indicate a poor prognosis. The major complaint of the patients is pain, which is usually severe and often intractable. These patients need multidisciplinary care