- Email: [email protected]
Kyphoplasty and Vertebroplasty for the Treatment of Spinal Metastases
Volume 3, Number 1 • October 2005
comprehensive review
Key words: Minimally invasive treatment, Spinal surgery, Vertebral augmentation
Kyphoplasty and Vertebroplasty for the Treatment of Spinal Metastases A. Jay Khanna,1 Phillip Neubauer,1 Daisuke Togawa,2 Mary Kay Reinhardt,2 Isador H. Lieberman2
Abstract Advances in the detection and treatment of many cancers have led to prolonged life and improved quality of life for patients with localized and metastatic cancer; however, the improved survival of patients with osseous lesions, coupled with the destructive nature of metastatic disease and the medications to treat these lesions, has increased the likelihood of vertebral body collapse. Conventional surgical techniques are often poorly tolerated by this patient population, whereas nonoperative management can lead to continued pain and diminished function in the terminal years of life. Vertebroplasty and kyphoplasty are minimally invasive vertebral augmentation techniques used to treat pain in such patients while maintaining a positive safety profile. Vertebroplasty and kyphoplasty are tools in a spectrum of treatments for vertebral compression fractures secondary to osteoporosis and metastatic disease and are not mutually exclusive. Additional research in this area in large cohorts of patients is needed to establish these techniques as safe and clinically cost-effective methods of treating patients with vertebral compression fractures secondary to spinal metastases.
Introduction
body collapse, occurs in as many as 70% of patients with multiple myeloma or metastatic cancer.10,11 As many as 50% of these destructive lesions are clinically silent, yet pain is the most common presenting symptom in as many as 90% of patients. Advances in the detection and treatment of many cancers have led to prolonged life and improved quality of life (QOL) for patients with localized and metastatic cancer. The improved survival of patients with osseous lesions, coupled with the destructive nature of metastatic disease and the medications used to treat these lesions, has increased the like-
The spine is the most common site for metastasis to bone in patients with cancer.1,2 Approximately 70% of spinal metastases occur in the thoracic spine, whereas the lumbar and cervical spine account for approximately 20% and 10% of cases, respectively.3,4 Spinal metastatic disease can occur in the paraspinal regions, in the osseous vertebral column, or in the epidural and subarachnoid spaces. The vast majority of spinal metastatic disease occurs as a result of breast, lung, and prostate cancer and from lymphoma and myeloma.5-9 Destruction of the vertebral body, manifested as vertebral
1Johns Hopkins Orthopaedics at Good Samaritan Hospital, Baltimore, MD 2Cleveland Clinic Spine Institute and Minimally Invasive Surgery Center,
Address for correspondence: A. Jay Khanna, MD, c/o Elaine P. Henze, Medical Editor, Department of Orthopaedic Surgery, Johns Hopkins Bayview Medical Center, 4940 Eastern Ave, #A672, Baltimore, MD 21224-2780 Fax: 410-550-2899; e-mail: [email protected]
Cleveland Clinic Foundation, OH
Submitted: May 18, 2005; Revised: Jun 26, 2005; Accepted: Sep 26, 2005 Supportive Cancer Therapy, Vol 3, No 1, 21-25, 2005
Electronic forwarding or copying is a violation of US and International Copyright Laws. Authorization to photocopy items for internal or personal use, or the internal or personal use of specific clients, is granted by Cancer Information Group, ISSN #1543-2912, provided the appropriate fee is paid directly to Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923 USA 978-750-8400.
21
Supportive Cancer Therapy
Kyphoplasty and Vertebroplasty for Spinal Metastases
Figure 1
ment of vertebral body hemangiomas. Later, its use was expanded to the treatment of pain associated with vertebral compression fractures. Vertebroplasty stabilizes a compression fracture but does not directly restore the vertebral body height. In many circumstances, vertebroplasty can be performed with the patient under light sedation and local anesthesia. Relative contraindications for vertebroplasty are vertebral collapse of > 60%, destruction of the posterior cortex of the vertebral body, and coagulopathy.13,14 Because the PMMA used is of low viscosity and is injected into a collapsed vertebral body, extravasation from the vertebral body can occur and can lead to cord compromise, necessitating emergent decompression.13-15 However, it should be noted that the incidence of symptomatic complications secondary to these cement extravasations is reported to be low.15-17 Although the incidence rate is small, the potential exists for PMMA to extravagate into perivertebral veins, leading to pulmonary cement embolism.18-20 Vertebroplasty has been shown to be safe and effective for the treatment of pain in patients with osteoporotic compression fractures, osteolytic metastases, hemangiomas, and multiple myeloma.13,14,21-24 Barr et al21 and others22,23 have reported a success rate of > 90% in the treatment of pain in patients with osteoporotic compression fractures, with a long-term follow-up of 10 years in some cases. Barr et al retrospectively reviewed the results of 38 patients with vertebral compression fractures treated with vertebroplasty and found that 36 of those patients experienced immediate pain relief.21 Of the 38 patients treated, 8 had compression fractures resulting from a malignant neoplasm, 4 of whom experienced pain relief.13 Weill et al treated 37 patients who had metastatic compression fractures with vertebroplasty and found that 24 of 37 experienced some degree of pain relief.24 Cotten and colleagues treated 40 patients who had compression fractures and reported that 94% stated they had relief from their pain.14
Images from a Patient with Renal Cell Carcinoma and Low Back Pain A
C
B
(A) Lateral preoperative radiograph and (B) sagittal T2-weighted magnetic resonance image show a lesion within the L1 vertebral body. (C) A postkyphoplasty lateral radiograph shows containment of the cement at the L1 level.
lihood of vertebral body collapse. Because patients with metastatic cancer are living longer, an effort must be made to maintain or improve their QOL by emphasizing the treatment of cancer- and medication-related complications such as compression fractures. If left untreated, vertebral body compression fractures can progress to adjacent level collapse, cord compromise, and intractable pain. Many clinicians have argued that such patients should be treated much like a patient with osteoporosis and a compression fracture.12 Minimally invasive surgical interventions, such as vertebroplasty and kyphoplasty, have shown promise in the treatment of vertebral compression fractures in patients with cancer.
Kyphoplasty Kyphoplasty is an advanced minimally invasive surgical technique designed to restore spinal alignment and stabilize vertebral fractures. The surgical technique has some components similar to those of vertebroplasty, primarily relating to the method of access to the vertebral body. Under fluoroscopic guidance, the surgeon places a cannula into the vertebral body, through which an inflatable bone tamp is inserted. The inflatable bone tamp is essentially a balloon that is used in an effort to elevate the compressed endplates toward their original height and create a cavity into which the PMMA can be deposited. Kyphoplasty offers 2 theoretical advantages over vertebroplasty. First, realignment of the vertebral body can reduce the transmission of abnormally high forces to the adjacent verte-
Vertebroplasty Percutaneous vertebroplasty is a minimally invasive technique in which polymethylmethacrylate (PMMA) is injected into a compressed vertebral body under fluoroscopic guidance. The technique was originally used for the treat-
22
Volume 3, Number 1 • October 2005
A. Jay Khanna et al
1980s, whereas kyphoplasty was introduced in 1997. Only recently has kyphoplasty been studied as a treatment for vertebral compression fractures that result from multiple myeloma and spinal metastases. We discuss in the following sections our experience with the use of kyphoplasty for patients with these 2 disease processes.
bral bodies (caused by the kyphotic posture) and can decrease the risk of adjacent level collapse, which would improve patient functional outcome.25 This procedure also reduces pain by stabilizing the fracture and restoring near-normal biomechanical forces. Second, the surgeon reduces the risk of extravasation by using partially cured high-viscosity cement, which is deposited into the cavity (Figure 1). In the United States, > 30,000 kyphoplasty procedures have been performed since 1998. Published data have shown > 90% improvement in patients’ pain scores and a substantial improvement in patients’ spinal alignment and QOL.26-28 The current indication for kyphoplasty in the United States is a painful, progressive vertebral body compression fracture resulting from osteoporosis or osteolysis. Contraindications to kyphoplasty are local osteomyelitis, osteoblastic lesions, sepsis, prolonged bleeding times, or any systemic condition that could prohibit the safe completion of the technique under general anesthesia.26-28 Relative contraindications to kyphoplasty include burst fractures and compression fractures that have obliterated the posterior cortex of the vertebral body. The primary goals of kyphoplasty are to restore stability, gain anatomic alignment, and reduce pain while maintaining a positive patient safety profile. Because most vertebral compression fractures heal eventually,21 the argument can be made that any invasive procedure, even a minimally invasive one, is unwarranted. An equally compelling argument for kyphoplasty can be made based on the fact that a collapsed vertebra alters spinal biomechanics and increases the incidence of adjacent vertebral body collapse by a factor of 5.25 A vicious cycle of altered forces leading to increased stress throughout the spinal column can cause eventual collapse of multiple vertebral bodies, thus increasing patient morbidity and mortality.25,29-32 If one believes in the orthopedic principle that restoration of normal alignment restores normal mechanical function, which ultimately leads to better patient outcome, then kyphoplasty offers a unique method for breaking the cycle of collapse and biomechanical imbalance. With this in mind, protection of anatomic alignment and sagittal balance becomes a principal indication for kyphoplasty, and the relief of pain becomes an added benefit rather than a primary indication driving intervention.
Multiple Myeloma Multiple myeloma is a monoclonal malignancy of plasma cells that produce and secrete proinflammatory cytokines. The cytokines cause bone resorption that, together with the highly vascularized nature of the tumor, leads to a high rate of compression fractures. Dudeney et al have reported satisfactory results after kyphoplasty as treatment for osteolytic vertebral compression fractures secondary to multiple myeloma.27 To date, we have used kyphoplasty to treat 80 patients with multiple myeloma and associated vertebral body compression fractures (unpublished data, 2005).35 The mean age of our patients at the time of the procedure was 60.6 years (range, 35-85 years). Preoperative and postoperative Short Form–36 (SF-36) QOL scores were available for 61 of 80 patients with a mean follow-up of 15.6 months (range, 2-59 months). No major complications related to the technique have been observed. Significant (P < 0.05) improvement in SF-36 scores (preoperative vs. postoperative, respectively) were observed for the following areas: bodily pain, 23 versus 44.4 (P < 0.001); physical function, 25.5 versus 36.6 (P = 0.034); vitality, 30.3 versus 38.1 (P = 0.039); and social functioning, 35.4 versus 67.5 (P < 0.001). Mental health scores showed an improvement of 60.3 versus 66.2 (P < 0.001), whereas role emotion and general health were essentially unchanged (P = 0.086 and P = 0.054, respectively). We believe these results suggest that kyphoplasty is efficacious in the treatment of vertebral body compression fractures secondary to multiple myeloma. Spinal Metastases Kyphoplasty for the treatment of compression fractures resulting from spinal metastases also has shown favorable results. We have treated 21 patients during a 3-year period in an ongoing study evaluating kyphoplasty for the treatment of spinal metastases (unpublished data, 2005).36 The mean age of the patients was 60.8 years (range, 40-88 years). The indication for the kyphoplasty procedure was painful osteolytic vertebral body compression fracture. Symptomatic levels were identified with plain radiographs and magnetic resonance imaging. The primary sources of the metastases included breast cancer (n = 9), lymphoma (n = 4), lung cancer (n = 3), and cancer of unknown location (n = 5). Postoperative evaluation showed that the procedure was well tolerated, with alleviation of pain that resulted in early mobilization in all 21 patients. Preoperative and postoperative SF36 data were available for 14 of the 21 patients, with a mean follow-up of 50 weeks (range, 3-206 weeks). Significant
Vertebroplasty and Kyphoplasty for the Treatment of Osteolytic Vertebral Collapse Vertebroplasty12,15,24,33,34 and kyphoplasty12,34 have been shown to produce good results when treating pain in patients with osteolytic vertebral collapse secondary to multiple myeloma and metastatic disease. To date, more patients have been treated with vertebroplasty than with kyphoplasty, partly because vertebroplasty has been in use since the
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Supportive Cancer Therapy
Kyphoplasty and Vertebroplasty for Spinal Metastases
treatment for vertebral compression fractures secondary to osteoporosis or metastatic disease, should not be considered mutually exclusive.
improvement (preoperative vs. postoperative SF-36 scores, respectively) was noted in the following areas: physical function, 20.9 versus 33.5 (P = 0.036); vitality, 31.2 versus 42.9 (P = 0.012); and social function, 37.5 versus 66.1 (P = 0.011). Nonsignificant changes occurred in mental health (60 vs. 62), role emotion (55.5 vs. 51.3), general health (52.1 vs. 46), bodily pain (31.6 vs. 39), and pain, as measured by the visual analog scale (6.5 vs. 3.9). All 21 patients tolerated the procedure well, and there were no substantial systemic complications. The fact that we found statistically significant improvements in only 3 SF-36 subscores might be a result of the relatively small number of patients currently available. Because there was a trend toward decreased pain after kyphoplasty, we anticipate that, as our study continues, we will be able to report results similar to those in patients with multiple myeloma. It is important to note that our primary indications for the treatment of these patients were palliation and the avoidance of conventional surgical procedures that could have a negative impact on the general QOL of these patients with multiple medical comorbidities and limited life expectancies. The fact that we were able to show a decrease in visual analog scale pain scores from 6.5 to 3.9, although not statistically significant, suggests that there was a trend toward pain control.
Future Directions Research continues in the use of vertebroplasty and kyphoplasty for the treatment of patients with spinal metastases. Currently, the use of these procedures in conjunction with radiation therapy is being evaluated as a potential method of attacking the malignant process biomechanically and biologically. In addition, the access portals that permit the placement of working cannulas into the vertebral body for a vertebral augmentation procedure can also be used to instill chemotherapeutic agents or to perform brachytherapy-type procedures. As with other areas of investigation, the potential benefits of these procedures must be weighed against the potential deleterious effects of delivering various chemotherapeutic and radioactive agents in close proximity to the neural elements.
Conclusion Vertebral body compression fractures associated with osteoporosis or osteolysis are a major problem that will continue to increase in frequency as our ability to diagnose and treat neoplasms improves and as the population ages. Although most compression fractures are clinically silent, they are not without potential for serious complications, including pain, deformity, and neurologic and respiratory compromise. Vertebroplasty is a minimally invasive procedure that has been shown to be safe and effective for the treatment of osteoporotic and malignant osteolytic compression fractures. The safety profile of vertebroplasty has been established, with most complications being minor or clinically insignificant and resulting from the cement used in the procedure rather than the placement of the cannula. Kyphoplasty represents an alternative to vertebroplasty that might offer improvement in efficacy and safety. Our preliminary results with kyphoplasty for the treatment of vertebral compression fractures in patients with multiple myeloma and metastatic spinal malignancies suggest the procedure is well tolerated and efficacious. Statistically significant improvement was seen in physical functioning, vitality, and social functioning when measured by the SF-36 outcomes instrument. Although more data are needed to evaluate the use of kyphoplasty for the treatment of malignant compression fractures, the evidence is compelling that kyphoplasty can be used safely in the treatment of metastatic lesions of the vertebral body in patients who were previously considered poor surgical candidates because of limited life expectancy or the presence of other medical comorbidities. Vertebroplasty and kyphoplasty offer minimally invasive techniques that can improve outcomes and the QOL in the terminal years for patients who might not be able to tolerate conventional surgical procedures.
Vertebroplasty Versus Kyphoplasty As noted in our review, the literature supports the premise that kyphoplasty and vertebroplasty provide pain relief to patients with painful vertebral body compression fractures. It is the clinician’s role to decide which technique offers the greatest overall benefit to the patient. By restoring vertebral body height, kyphoplasty has the theoretical advantage of restoring normal spinal alignment and biomechanics. The restoration to near-normal alignment decreases abnormal forces throughout the spinal cord, thus potentially decreasing the incidence of adjacent-level vertebral body collapse. Kyphoplasty also has a lower rate of PMMA extravasation than vertebroplasty34,37 and thus a lower risk of neurologic compromise. Fourney et al reported that in 97 patients with cancer treated with vertebroplasty or kyphoplasty, asymptomatic cement leakage occurred at 6 of 65 (9.2%) levels treated with vertebroplasty, whereas no cement extravasation was seen at the 32 levels treated with kyphoplasty.34 The mean percentage of restored vertebral body height provided by kyphoplasty in that study was 42% ± 21%. Another study of osteoporotic vertebral compression fractures has shown 46.8% height restoration in 70% of vertebral bodies treated with kyphoplasty.28 Although vertebroplasty might not restore vertebral body height directly, the procedure might be more appropriate than kyphoplasty for stabilization of an at-risk vertebral body with a subclinical metastasis or a vertebral body with minor, minimally displaced endplate fractures. Vertebroplasty and kyphoplasty, tools in a spectrum of
24
Volume 3, Number 1 • October 2005
A. Jay Khanna et al
References
tebroplasty with polymethylmethacrylate. Spine 2004; 29:E294-E297. 21. Barr JD, Barr MS, Lemley TJ, et al. Percutaneous vertebroplasty for pain relief and spinal stabilization. Spine 2000; 25:923-928. 22. Deramond H, Depriester C, Galibert P, et al. Percutaneous vertebroplasty with polymethylmethacrylate. Technique, indications, and results. Radiol Clin North Am 1998; 36:533-546. 23. 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; 18:1897-1904. 24. Weill A, Chiras J, Simon JM, et al. Spinal metastases: indications for and results of percutaneous injection of acrylic surgical cement. Radiology 1996; 199:241-247. 25. Kayanja MM, Ferrara LA, Lieberman IH. Distribution of anterior cortical shear strain after a thoracic wedge compression fracture. Spine J 2004; 4:76-87. 26. Coumans JVCE, Reinhardt MK, Lieberman IH. Kyphoplasty for vertebral compression fractures: 1-year clinical outcomes from a prospective study. J Neurosurg 2003; 99:44-50. 27. Dudeney S, Lieberman IH, Reinhardt MK, et al. Kyphoplasty in the treatment of osteolytic vertebral compression fractures as a result of multiple myeloma. J Clin Oncol 2002; 20:2382-2387. 28. Lieberman IH, Dudeney S, Reinhardt MK, et al. Initial outcome and efficacy of “kyphoplasty” in the treatment of painful osteoporotic vertebral compression fractures. Spine 2001; 26:1631-1638. 29. Harrop JS, Prpa B, Reinhardt MK, et al. Primary and secondary osteoporosis’ incidence of subsequent vertebral compression fractures after kyphoplasty. Spine 2004; 29:2120-2125. 30. Hasserius R, Karlsson MK, Nilsson BE, et al. Prevalent vertebral deformities predict increased mortality and increased fracture rate in both men and women: a 10-year population-based study of 598 individuals from the Swedish cohort in the European Vertebral Osteoporosis Study. Osteoporos Int 2003; 14:61-68. 31. Lindsay R, Silverman SL, Cooper C, et al. Risk of new vertebral fracture in the year following a fracture. JAMA 2001; 285:320-323. 32. Silverman SL. The clinical consequences of vertebral compression fracture. Bone 1992; 13:S27-S31. 33. Chow E, Holden L, Danjoux C, et al. Successful salvage using percutaneous vertebroplasty in cancer patients with painful spinal metastases or osteoporotic compression fractures. Radiother Oncol 2004; 70:265-267. 34. Fourney DR, Schomer DF, Nader R, et al. Percutaneous vertebroplasty and kyphoplasty for painful vertebral body fractures in cancer patients. J Neurosurg 2003; 98:21-30. 35. Khanna AJ, Reinhardt MK, Togawa D, et al. Clinical and functional outcomes of kyphoplasty for vertebral compression fractures. Presented at the Annual Meeting of the North American Spine Society (NASS); October 29, 2004; Melville, NY. 36. Khanna AJ, Reinhardt MK, Togawa D, et al. Functional outcomes of kyphoplasty for the treatment of spinal metastases. Presented at the International Meeting on Advanced Spinal Technologies (IMAST); July 3, 2004; Southampton, Bermuda. 37. Phillips FM, Wetzel TF, Lieberman I, et al. An in vivo comparison of the potential for extravertebral cement leak after vertebroplasty and kyphoplasty. Spine 2002; 27:2173-2178.
1. Gokaslan ZL. Spine surgery for cancer. Curr Opin Oncol 1996; 8:178-181. 2. Steinmetz MP, Mekhail A, Benzel EC. Management of metastatic tumors of the spine: strategies and operative indications. Neurosurg Focus 2001; 11:1-6. 3. Barron KD, Hirano A, Araki S, et al. Experiences with metastatic neoplasms involving the spinal cord. Neurology 1959; 9:91-106. 4. Gerszten PC, Welch WC. Current surgical management of metastatic spinal disease. Oncology (Huntingt) 2000; 14:1013-1024. 5. Adams M, Sonntag VK. Surgical treatment of metastatic cervical spine disease. Contemp Neurosurg 2001; 23:1-5. 6. Byrne TN. Spinal cord compression from epidural metastases. N Engl J Med 1992; 327:614-619. 7. Gilbert RW, Kim JH, Posner JB. Epidural spinal cord compression from metastatic tumor: diagnosis and treatment. Ann Neurol 1978; 3:40-51. 8. McLain RF, Weinstein JN. Tumors of the spine. Semin Spine Surg 1990; 2:157-180. 9. Wong DA, Fornasier VL, Macnab I. Spinal metastases: the obvious, the occult, and the impostors. Spine 1990; 15:1-4. 10. McLain RF, Weinstein JN. Tumors of the Spine. In: Herkowitz HN, Garfin SR, Balderston RA, et al, eds. Rothman-Simeone: The Spine, 4th ed. Philadelphia: WB Saunders, 1999:1171-1206. 11. Sundaresan N, Krol G, Digiacinto GV, et al. Metastatic tumors of the spine. In: Sundaresan N, Schmidek HH, Schiller AL, et al, eds. Tumors of the Spine: Diagnosis and Clinical Management. Philadelphia: WB Saunders, 1990:279-304. 12. Lieberman I, Reinhardt MK. Vertebroplasty and kyphoplasty for osteolytic vertebral collapse. Clin Orthop Rel Res 2003; 415(suppl):S176-S186. 13. Bai B, Jazrawi LM, Kummer FJ, et al. The use of an injectable, biodegradable calcium phosphate bone substitute for the prophylactic augmentation of osteoporotic vertebrae and the management of vertebral compression fractures. Spine 1999; 24:1521-1526. 14. Cotten A, Boutry N, Cortet B, et al. Percutaneous vertebroplasty: state of the art. Radiographics 1998; 18:311-323. 15. Cotten A, Dewatre F, Cortet B, et al. Percutaneous vertebroplasty for osteolytic metastases and myeloma: effects of the percentage of lesion filling and the leakage of methyl methacrylate at clinical follow-up. Radiology 1996; 200:525-530. 16. Grohs JG, Matzner M, Trieb K, et al. Minimal invasive stabilization of osteoporotic vertebral fractures: a prospective nonrandomized comparison of vertebroplasty and balloon kyphoplasty. J Spinal Disord Tech 2005; 18:238-242. 17. Mathis JM, Barr JD, Belkoff SM, et al. Percutaneous vertebroplasty: a developing standard of care for vertebral compression fractures. AJNR Am J Neuroradiol 2001; 22:373-381. 18. Choe DH, Marom EM, Ahrar K, et al. Pulmonary embolism of polymethyl methacrylate during percutaneous vertebroplasty and kyphosplasty. AJR Am J Roentgenol 2004; 183:1097-1102. 19. Jang JS, Lee SH, Jung SK. Pulmonary embolism of polymethylmethacrylate after percutaneous vertebroplasty: a report of three cases. Spine 2002; 27:E416-E418. 20. Yoo KY, Jeong SW, Yoon W, et al. Acute respiratory distress syndrome associated with pulmonary cement embolism following percutaneous ver-
25
comprehensive review
Key words: Minimally invasive treatment, Spinal surgery, Vertebral augmentation
Kyphoplasty and Vertebroplasty for the Treatment of Spinal Metastases A. Jay Khanna,1 Phillip Neubauer,1 Daisuke Togawa,2 Mary Kay Reinhardt,2 Isador H. Lieberman2
Abstract Advances in the detection and treatment of many cancers have led to prolonged life and improved quality of life for patients with localized and metastatic cancer; however, the improved survival of patients with osseous lesions, coupled with the destructive nature of metastatic disease and the medications to treat these lesions, has increased the likelihood of vertebral body collapse. Conventional surgical techniques are often poorly tolerated by this patient population, whereas nonoperative management can lead to continued pain and diminished function in the terminal years of life. Vertebroplasty and kyphoplasty are minimally invasive vertebral augmentation techniques used to treat pain in such patients while maintaining a positive safety profile. Vertebroplasty and kyphoplasty are tools in a spectrum of treatments for vertebral compression fractures secondary to osteoporosis and metastatic disease and are not mutually exclusive. Additional research in this area in large cohorts of patients is needed to establish these techniques as safe and clinically cost-effective methods of treating patients with vertebral compression fractures secondary to spinal metastases.
Introduction
body collapse, occurs in as many as 70% of patients with multiple myeloma or metastatic cancer.10,11 As many as 50% of these destructive lesions are clinically silent, yet pain is the most common presenting symptom in as many as 90% of patients. Advances in the detection and treatment of many cancers have led to prolonged life and improved quality of life (QOL) for patients with localized and metastatic cancer. The improved survival of patients with osseous lesions, coupled with the destructive nature of metastatic disease and the medications used to treat these lesions, has increased the like-
The spine is the most common site for metastasis to bone in patients with cancer.1,2 Approximately 70% of spinal metastases occur in the thoracic spine, whereas the lumbar and cervical spine account for approximately 20% and 10% of cases, respectively.3,4 Spinal metastatic disease can occur in the paraspinal regions, in the osseous vertebral column, or in the epidural and subarachnoid spaces. The vast majority of spinal metastatic disease occurs as a result of breast, lung, and prostate cancer and from lymphoma and myeloma.5-9 Destruction of the vertebral body, manifested as vertebral
1Johns Hopkins Orthopaedics at Good Samaritan Hospital, Baltimore, MD 2Cleveland Clinic Spine Institute and Minimally Invasive Surgery Center,
Address for correspondence: A. Jay Khanna, MD, c/o Elaine P. Henze, Medical Editor, Department of Orthopaedic Surgery, Johns Hopkins Bayview Medical Center, 4940 Eastern Ave, #A672, Baltimore, MD 21224-2780 Fax: 410-550-2899; e-mail: [email protected]
Cleveland Clinic Foundation, OH
Submitted: May 18, 2005; Revised: Jun 26, 2005; Accepted: Sep 26, 2005 Supportive Cancer Therapy, Vol 3, No 1, 21-25, 2005
Electronic forwarding or copying is a violation of US and International Copyright Laws. Authorization to photocopy items for internal or personal use, or the internal or personal use of specific clients, is granted by Cancer Information Group, ISSN #1543-2912, provided the appropriate fee is paid directly to Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923 USA 978-750-8400.
21
Supportive Cancer Therapy
Kyphoplasty and Vertebroplasty for Spinal Metastases
Figure 1
ment of vertebral body hemangiomas. Later, its use was expanded to the treatment of pain associated with vertebral compression fractures. Vertebroplasty stabilizes a compression fracture but does not directly restore the vertebral body height. In many circumstances, vertebroplasty can be performed with the patient under light sedation and local anesthesia. Relative contraindications for vertebroplasty are vertebral collapse of > 60%, destruction of the posterior cortex of the vertebral body, and coagulopathy.13,14 Because the PMMA used is of low viscosity and is injected into a collapsed vertebral body, extravasation from the vertebral body can occur and can lead to cord compromise, necessitating emergent decompression.13-15 However, it should be noted that the incidence of symptomatic complications secondary to these cement extravasations is reported to be low.15-17 Although the incidence rate is small, the potential exists for PMMA to extravagate into perivertebral veins, leading to pulmonary cement embolism.18-20 Vertebroplasty has been shown to be safe and effective for the treatment of pain in patients with osteoporotic compression fractures, osteolytic metastases, hemangiomas, and multiple myeloma.13,14,21-24 Barr et al21 and others22,23 have reported a success rate of > 90% in the treatment of pain in patients with osteoporotic compression fractures, with a long-term follow-up of 10 years in some cases. Barr et al retrospectively reviewed the results of 38 patients with vertebral compression fractures treated with vertebroplasty and found that 36 of those patients experienced immediate pain relief.21 Of the 38 patients treated, 8 had compression fractures resulting from a malignant neoplasm, 4 of whom experienced pain relief.13 Weill et al treated 37 patients who had metastatic compression fractures with vertebroplasty and found that 24 of 37 experienced some degree of pain relief.24 Cotten and colleagues treated 40 patients who had compression fractures and reported that 94% stated they had relief from their pain.14
Images from a Patient with Renal Cell Carcinoma and Low Back Pain A
C
B
(A) Lateral preoperative radiograph and (B) sagittal T2-weighted magnetic resonance image show a lesion within the L1 vertebral body. (C) A postkyphoplasty lateral radiograph shows containment of the cement at the L1 level.
lihood of vertebral body collapse. Because patients with metastatic cancer are living longer, an effort must be made to maintain or improve their QOL by emphasizing the treatment of cancer- and medication-related complications such as compression fractures. If left untreated, vertebral body compression fractures can progress to adjacent level collapse, cord compromise, and intractable pain. Many clinicians have argued that such patients should be treated much like a patient with osteoporosis and a compression fracture.12 Minimally invasive surgical interventions, such as vertebroplasty and kyphoplasty, have shown promise in the treatment of vertebral compression fractures in patients with cancer.
Kyphoplasty Kyphoplasty is an advanced minimally invasive surgical technique designed to restore spinal alignment and stabilize vertebral fractures. The surgical technique has some components similar to those of vertebroplasty, primarily relating to the method of access to the vertebral body. Under fluoroscopic guidance, the surgeon places a cannula into the vertebral body, through which an inflatable bone tamp is inserted. The inflatable bone tamp is essentially a balloon that is used in an effort to elevate the compressed endplates toward their original height and create a cavity into which the PMMA can be deposited. Kyphoplasty offers 2 theoretical advantages over vertebroplasty. First, realignment of the vertebral body can reduce the transmission of abnormally high forces to the adjacent verte-
Vertebroplasty Percutaneous vertebroplasty is a minimally invasive technique in which polymethylmethacrylate (PMMA) is injected into a compressed vertebral body under fluoroscopic guidance. The technique was originally used for the treat-
22
Volume 3, Number 1 • October 2005
A. Jay Khanna et al
1980s, whereas kyphoplasty was introduced in 1997. Only recently has kyphoplasty been studied as a treatment for vertebral compression fractures that result from multiple myeloma and spinal metastases. We discuss in the following sections our experience with the use of kyphoplasty for patients with these 2 disease processes.
bral bodies (caused by the kyphotic posture) and can decrease the risk of adjacent level collapse, which would improve patient functional outcome.25 This procedure also reduces pain by stabilizing the fracture and restoring near-normal biomechanical forces. Second, the surgeon reduces the risk of extravasation by using partially cured high-viscosity cement, which is deposited into the cavity (Figure 1). In the United States, > 30,000 kyphoplasty procedures have been performed since 1998. Published data have shown > 90% improvement in patients’ pain scores and a substantial improvement in patients’ spinal alignment and QOL.26-28 The current indication for kyphoplasty in the United States is a painful, progressive vertebral body compression fracture resulting from osteoporosis or osteolysis. Contraindications to kyphoplasty are local osteomyelitis, osteoblastic lesions, sepsis, prolonged bleeding times, or any systemic condition that could prohibit the safe completion of the technique under general anesthesia.26-28 Relative contraindications to kyphoplasty include burst fractures and compression fractures that have obliterated the posterior cortex of the vertebral body. The primary goals of kyphoplasty are to restore stability, gain anatomic alignment, and reduce pain while maintaining a positive patient safety profile. Because most vertebral compression fractures heal eventually,21 the argument can be made that any invasive procedure, even a minimally invasive one, is unwarranted. An equally compelling argument for kyphoplasty can be made based on the fact that a collapsed vertebra alters spinal biomechanics and increases the incidence of adjacent vertebral body collapse by a factor of 5.25 A vicious cycle of altered forces leading to increased stress throughout the spinal column can cause eventual collapse of multiple vertebral bodies, thus increasing patient morbidity and mortality.25,29-32 If one believes in the orthopedic principle that restoration of normal alignment restores normal mechanical function, which ultimately leads to better patient outcome, then kyphoplasty offers a unique method for breaking the cycle of collapse and biomechanical imbalance. With this in mind, protection of anatomic alignment and sagittal balance becomes a principal indication for kyphoplasty, and the relief of pain becomes an added benefit rather than a primary indication driving intervention.
Multiple Myeloma Multiple myeloma is a monoclonal malignancy of plasma cells that produce and secrete proinflammatory cytokines. The cytokines cause bone resorption that, together with the highly vascularized nature of the tumor, leads to a high rate of compression fractures. Dudeney et al have reported satisfactory results after kyphoplasty as treatment for osteolytic vertebral compression fractures secondary to multiple myeloma.27 To date, we have used kyphoplasty to treat 80 patients with multiple myeloma and associated vertebral body compression fractures (unpublished data, 2005).35 The mean age of our patients at the time of the procedure was 60.6 years (range, 35-85 years). Preoperative and postoperative Short Form–36 (SF-36) QOL scores were available for 61 of 80 patients with a mean follow-up of 15.6 months (range, 2-59 months). No major complications related to the technique have been observed. Significant (P < 0.05) improvement in SF-36 scores (preoperative vs. postoperative, respectively) were observed for the following areas: bodily pain, 23 versus 44.4 (P < 0.001); physical function, 25.5 versus 36.6 (P = 0.034); vitality, 30.3 versus 38.1 (P = 0.039); and social functioning, 35.4 versus 67.5 (P < 0.001). Mental health scores showed an improvement of 60.3 versus 66.2 (P < 0.001), whereas role emotion and general health were essentially unchanged (P = 0.086 and P = 0.054, respectively). We believe these results suggest that kyphoplasty is efficacious in the treatment of vertebral body compression fractures secondary to multiple myeloma. Spinal Metastases Kyphoplasty for the treatment of compression fractures resulting from spinal metastases also has shown favorable results. We have treated 21 patients during a 3-year period in an ongoing study evaluating kyphoplasty for the treatment of spinal metastases (unpublished data, 2005).36 The mean age of the patients was 60.8 years (range, 40-88 years). The indication for the kyphoplasty procedure was painful osteolytic vertebral body compression fracture. Symptomatic levels were identified with plain radiographs and magnetic resonance imaging. The primary sources of the metastases included breast cancer (n = 9), lymphoma (n = 4), lung cancer (n = 3), and cancer of unknown location (n = 5). Postoperative evaluation showed that the procedure was well tolerated, with alleviation of pain that resulted in early mobilization in all 21 patients. Preoperative and postoperative SF36 data were available for 14 of the 21 patients, with a mean follow-up of 50 weeks (range, 3-206 weeks). Significant
Vertebroplasty and Kyphoplasty for the Treatment of Osteolytic Vertebral Collapse Vertebroplasty12,15,24,33,34 and kyphoplasty12,34 have been shown to produce good results when treating pain in patients with osteolytic vertebral collapse secondary to multiple myeloma and metastatic disease. To date, more patients have been treated with vertebroplasty than with kyphoplasty, partly because vertebroplasty has been in use since the
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Supportive Cancer Therapy
Kyphoplasty and Vertebroplasty for Spinal Metastases
treatment for vertebral compression fractures secondary to osteoporosis or metastatic disease, should not be considered mutually exclusive.
improvement (preoperative vs. postoperative SF-36 scores, respectively) was noted in the following areas: physical function, 20.9 versus 33.5 (P = 0.036); vitality, 31.2 versus 42.9 (P = 0.012); and social function, 37.5 versus 66.1 (P = 0.011). Nonsignificant changes occurred in mental health (60 vs. 62), role emotion (55.5 vs. 51.3), general health (52.1 vs. 46), bodily pain (31.6 vs. 39), and pain, as measured by the visual analog scale (6.5 vs. 3.9). All 21 patients tolerated the procedure well, and there were no substantial systemic complications. The fact that we found statistically significant improvements in only 3 SF-36 subscores might be a result of the relatively small number of patients currently available. Because there was a trend toward decreased pain after kyphoplasty, we anticipate that, as our study continues, we will be able to report results similar to those in patients with multiple myeloma. It is important to note that our primary indications for the treatment of these patients were palliation and the avoidance of conventional surgical procedures that could have a negative impact on the general QOL of these patients with multiple medical comorbidities and limited life expectancies. The fact that we were able to show a decrease in visual analog scale pain scores from 6.5 to 3.9, although not statistically significant, suggests that there was a trend toward pain control.
Future Directions Research continues in the use of vertebroplasty and kyphoplasty for the treatment of patients with spinal metastases. Currently, the use of these procedures in conjunction with radiation therapy is being evaluated as a potential method of attacking the malignant process biomechanically and biologically. In addition, the access portals that permit the placement of working cannulas into the vertebral body for a vertebral augmentation procedure can also be used to instill chemotherapeutic agents or to perform brachytherapy-type procedures. As with other areas of investigation, the potential benefits of these procedures must be weighed against the potential deleterious effects of delivering various chemotherapeutic and radioactive agents in close proximity to the neural elements.
Conclusion Vertebral body compression fractures associated with osteoporosis or osteolysis are a major problem that will continue to increase in frequency as our ability to diagnose and treat neoplasms improves and as the population ages. Although most compression fractures are clinically silent, they are not without potential for serious complications, including pain, deformity, and neurologic and respiratory compromise. Vertebroplasty is a minimally invasive procedure that has been shown to be safe and effective for the treatment of osteoporotic and malignant osteolytic compression fractures. The safety profile of vertebroplasty has been established, with most complications being minor or clinically insignificant and resulting from the cement used in the procedure rather than the placement of the cannula. Kyphoplasty represents an alternative to vertebroplasty that might offer improvement in efficacy and safety. Our preliminary results with kyphoplasty for the treatment of vertebral compression fractures in patients with multiple myeloma and metastatic spinal malignancies suggest the procedure is well tolerated and efficacious. Statistically significant improvement was seen in physical functioning, vitality, and social functioning when measured by the SF-36 outcomes instrument. Although more data are needed to evaluate the use of kyphoplasty for the treatment of malignant compression fractures, the evidence is compelling that kyphoplasty can be used safely in the treatment of metastatic lesions of the vertebral body in patients who were previously considered poor surgical candidates because of limited life expectancy or the presence of other medical comorbidities. Vertebroplasty and kyphoplasty offer minimally invasive techniques that can improve outcomes and the QOL in the terminal years for patients who might not be able to tolerate conventional surgical procedures.
Vertebroplasty Versus Kyphoplasty As noted in our review, the literature supports the premise that kyphoplasty and vertebroplasty provide pain relief to patients with painful vertebral body compression fractures. It is the clinician’s role to decide which technique offers the greatest overall benefit to the patient. By restoring vertebral body height, kyphoplasty has the theoretical advantage of restoring normal spinal alignment and biomechanics. The restoration to near-normal alignment decreases abnormal forces throughout the spinal cord, thus potentially decreasing the incidence of adjacent-level vertebral body collapse. Kyphoplasty also has a lower rate of PMMA extravasation than vertebroplasty34,37 and thus a lower risk of neurologic compromise. Fourney et al reported that in 97 patients with cancer treated with vertebroplasty or kyphoplasty, asymptomatic cement leakage occurred at 6 of 65 (9.2%) levels treated with vertebroplasty, whereas no cement extravasation was seen at the 32 levels treated with kyphoplasty.34 The mean percentage of restored vertebral body height provided by kyphoplasty in that study was 42% ± 21%. Another study of osteoporotic vertebral compression fractures has shown 46.8% height restoration in 70% of vertebral bodies treated with kyphoplasty.28 Although vertebroplasty might not restore vertebral body height directly, the procedure might be more appropriate than kyphoplasty for stabilization of an at-risk vertebral body with a subclinical metastasis or a vertebral body with minor, minimally displaced endplate fractures. Vertebroplasty and kyphoplasty, tools in a spectrum of
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Volume 3, Number 1 • October 2005
A. Jay Khanna et al
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