Vertebroplasty and Kyphoplasty in Spinal Trauma

Abstract Kyphoplasty and vertebroplasty have become recognized procedures for the treatment of vertebral fractures, especially in patients with osteoporosis. In most cases of osteoporotic spinal vertebral fracture in elderly patients, polymethylmethacrylate (PMMA) cement is used to fill the defect and stabilize the vertebral body. The techniques of vertebroplasty and kyphoplasty differ in the possibility of realignment and reconstruction of the vertebral body and spinal column. Long-term results in terms of integration of the cement and bioreactivity of the vertebral body are still lacking; so, these procedures are still no options in the treatment of younger patients. Vertebroplasty and kyphoplasty show different success in the management of fresh traumatic spine fractures. The acute traumatic vertebral fracture has to be classified sensitively, to find the right indication for cement augmentation. Mild acute compression fractures can be treated by vertebroplasty or kyphoplasty, severe compression and burst fractures by combination of internal fixation and kyphoplasty. The indications for use of biological or osteoinductive cement in spinal fracture management must still be regarded as restricted owing to the lack of basic biomechanical research data. Such cement should not be used except in clinical studies.     

气囊扩张椎体后凸成形术的初步报告

目的:初步评价气囊扩张后突成形术治疗骨质疏松性椎体压缩骨折的手术操作、安全性、及疗效。方法:观察21例骨质疏松患者,30节椎体,新鲜骨折24椎节,陈旧性骨折6椎节,均有局部腰背疼痛,无神经症状。C-arm透视下,两侧同时经皮穿刺,气囊扩张骨折复位后,骨水泥灌注入椎体。随访4～7月。记录患者局部止痛的疗效,骨折的复位,及并发症等情况。结果:完全止痛14例,部分止痛7例,24节新鲜骨折气囊扩张的复位率是28.2％,6节陈旧性骨折复位率是2.1％。并发症2例,骨水泥外漏到椎间隙。其他椎体再次骨折2例,余无疼痛复发及椎体高度丢失。结论:气囊扩张后突成形术能恢复脊柱的稳定性,部分矫正脊柱后突,止痛疗效好,创伤小,并发症少,值得推广。     

Percutaneous vertebral augmentation: an elevation in adjacent-level fracture risk in kyphoplasty as compared with vertebroplasty.

BACKGROUND CONTEXT: Osteoporotic vertebral compression fractures (VCFs) are being increasingly treated with minimally invasive bone augmentation techniques such as kyphoplasty and vertebroplasty. Both are reported to be an effective means of pain relief; however, there may be an increased risk of developing subsequent VCFs after such procedures. PURPOSE: The purpose of this study was to compare the effectiveness and complication profile of kyphoplasty and vertebroplasty in a single patient series. STUDY DESIGN/SETTING: A clinical series of 36 patients with VCFs treated by vertebral augmentation procedures was retrospectively analyzed for surgical approach, volume of cement injected, cement extravasation (symptomatic and asymptomatic), the occurrence of subsequent adjacent level fracture, and pain relief. PATIENT SAMPLE: Thirty-six patients with 46 VCFs underwent either kyphoplasty or vertebroplasty after failing conservative therapy. The mean patient age was not significantly different between the kyphoplasty group (70; range, 46-83) and vertebroplasty group (72; range, 38-90) (p=.438). OUTCOME MEASURES: Outcomes were assessed by using self-report measures (a comparative pain rating scale) and physiologic measures (pre- and postoperative radiographs). METHODS: Thirty-six patients with VCFs underwent 46 augmentation procedures (17 patients had 20 fractures treated via kyphoplasty, and 19 patients had 26 fractures treated via vertebroplasty). Seventeen patients in this series underwent kyphoplasty using standard techniques involving bone void creation with balloon tamps, followed by cement injection. Nineteen patients underwent a percutaneous vertebroplasty procedure using a novel cannulated, fenestrated bone tap developed to direct cement anteriorly into the vertebral body to avoid backflow of cement onto neural elements. RESULTS: Pain improvement was seen in >90% of patients in both groups. Mean cement injection per vertebral body was 4.65 mL and 3.78 mL for the kyphoplasty and vertebroplasty groups, respectively (p=.014). Ninety-five percent of the kyphoplasty procedures were performed bilaterally, whereas only 19% of the vertebroplasty procedures required bilateral augmentation (p<.001). There was no cement extravasation resulting in radiculopathy, or myelopathy in either group. Asymptomatic cement extravasation was seen in 5 of 46 (11%) of the total series (3/20 [15%] and 2/26 [7.7%] of kyphoplasty and vertebroplasty, respectively) (p=.696). Within a 3-month period, there were 5 new adjacent level fractures seen in 3 patients who underwent a kyphoplasty procedure (5/20 [25%]) and none in the vertebroplasty group (p<.05). CONCLUSIONS: Vertebroplasty appears to offer a comparable rate of postoperative pain relief as kyphoplasty while using less bone cement more often via a unilateral approach and without the attendant risk of adjacent level fracture.     

Balloon kyphoplasty in the therapy of vertebral fractures

Approximately 500,000 vertebral fractures occur as a result of osteoporosis every year in Europe. One third of the patients thus affected complain of severe back pain and seek treatment. In the past, the treatment of such fractures was limited to conservative methods, such as the use of braces and analgesics and long-term immobilisation followed by physiotherapy. Since 1998 balloon kyphoplasty, a minimally invasive procedure, has also been available for their treatment. During balloon kyphoplasty a balloon system is introduced into a fractured vertebral body to achieve bitranspedicular augmentation, after which low-viscosity bone cement is injected into the vertebral body, where it sets very quickly. In general the patient can be fully mobilized 24-48 h after the procedure and in most cases the symptoms are then considerably attenuated; many patients are actually free of pain. Published studies and our own experience indicate that balloon kyphoplasty is a safe method of treating painful vertebral compression fractures sustained in various ways and that complications are rare with this procedure.     

Balloon kyphoplasty in the treatment of vertebral fractures

Approximately 500,000 vertebral fractures occur as a result of osteoporosis every year in Europe. One third of the patients thus affected complain of severe back pain and seek treatment. In the past, the treatment of such fractures was limited to conservative methods, such as the use of braces and analgesics and long-term immobilisation followed by physiotherapy. Since 1998 balloon kyphoplasty, a minimally invasive procedure, has also been available for their treatment. During balloon kyphoplasty a balloon system is introduced into the fractured vertebral body to achieve bitranspedicular augmentation, after which low-viscosity bone cement is injected into the vertebral body, where it sets very quickly. In general the patient can be fully mobilized 24-48 h after the procedure and in most cases the symptoms are then considerably attenuated; many patients are actually free of pain. Published studies and our own experience indicate that balloon kyphoplasty is a safe method of treating painful vertebral compression fractures sustained in various ways and that complications are rare with this procedure.     

Ballonkyphoplastie in der Therapie von Wirbelkörperfrakturen

Approximately 500,000 vertebral fractures occur as a result of osteoporosis every year in Europe. One third of the patients thus affected complain of severe back pain and seek treatment. In the past, the treatment of such fractures was limited to conservative methods, such as the use of braces and analgesics and long-term immobilisation followed by physiotherapy. Since 1998 balloon kyphoplasty, a minimally invasive procedure, has also been available for their treatment. During balloon kyphoplasty a balloon system is introduced into the fractured vertebral body to achieve bitranspedicular augmentation, after which low-viscosity bone cement is injected into the vertebral body, where it sets very quickly. In general the patient can be fully mobilized 24–48 h after the procedure and in most cases the symptoms are then considerably attenuated; many patients are actually free of pain. Published studies and our own experience indicate that balloon kyphoplasty is a safe method of treating painful vertebral compression fractures sustained in various ways and that complications are rare with this procedure.     

Percutaneous treatment of vertebral body pathology

Percutaneous vertebral body injection procedures currently are used to stabilize and reinforce weakened or fractured bone resulting from metastatic disease and severe osteoporosis. Both vertebroplasty and kyphoplasty can reinforce the structure of a vertebral body and provide pain relief, but the procedures have technical differences. Kyphoplasty improves vertebral height to varying degrees in nearly three quarters of patients. Kyphosis is improved more effectively when the procedure is performed within 3 months from the onset of fracture pain. To date, it is unknown whether vertebroplasty with preprocedure postural reduction can provide similar improvement of deformity. Complications are relatively infrequent with both vertebroplasty and kyphoplasty. Cement leakage from the vertebral body is more likely with vertebroplasty than with kyphoplasty. Leakage is more common in the treatment of pathologic fractures resulting from metastatic disease. Clinical complications caused by cement leakage and neural compression are infrequent. Specific indications for these injection procedures need to be more clearly refined. Long-term outcomes, including the fate of the injected material and the effect on adjacent vertebrae, have yet to be determined.     

Vertebroplastie: ein Update

Percutaneous cement augmentation (kyphoplasty and vertebroplasty) has become established as a procedure for treatment of painful osteoporotic vertebral fractures and certain neoplastic changes. The injection of cement ensures rapid stabilization of the vertebra and prevents further sintering. This also results in pain improvement. Nonetheless, based on two placebo-controlled trials, this treatment approach has been called into question. However, these studies did not take the technical aspects of the treatment into consideration, and it appears probable that the amount of filler material chosen was too small so that the treatment group also received placebo. Furthermore, it is likely that mostly older fractures were treated so that the effect can no longer be expected to be as pronounced. A randomized, controlled trial comparing kyphoplasty to conservative management provided good evidence that cement augmentation is of benefit within the first year. Newer procedures for kyphoplasty are very promising, but their clinical significance still needs verification.     

Sandwich Vertebral Fracture in the Study of Adjacent-level Fracture After Vertebral Cement Augmentation

The literature is inconclusive on the development of adjacent-level vertebral fracture after initial cement augmentation. A preliminary hypotheses is that cement injection exaggerates force transmission to the adjacent vertebral bodies, thereby predisposing those levels to future fractures. A sandwich vertebra is an intact vertebral body located between 2 previously cemented vertebrae. The purpose of this study was to determine whether the risk of adjacent-level fracture increased due to load shift after a cement injection procedure. The authors retrospectively investigated the rate of adjacent-level fracture after sandwiching compared with conservative treatment and determined the potential causative factors of sandwich vertebral fracture. Age, sex, weight, height, body mass index, follow-up period, and location of sandwich level (T10-L2 or nonT10-L2 junction) were assessed. Surgical variables, including surgical procedure (vertebroplasty or balloon kyphoplasty), surgical approach (through uni- or bilateral pedicle), volume of cement injected into the painful vertebrae, cement leakage into the intervertebral disk, cumulative number of treated levels, and pre- and postoperative kyphotic angulation of the sandwich region, were also analyzed. Nine of 42 sandwiched levels developed fatigue fractures, whereas 11 of 71 patients treated with conservative therapy sustained new vertebral fractures adjacent to the treated levels. Only preoperative kyphotic angulation was the variable positively associated with sandwich vertebral fracture at follow-up (P=.021). Although subjected to double load shifts, the sandwich vertebra was not prone to structural failure. Thus, cement augmentation protocol does not increase the incidence of adjacent vertebral fracture.     

Unsuspected lymphoma diagnosed with use of biopsy during kyphoplasty

BACKGROUND: Vertebral augmentation procedures are currently widely performed to treat vertebral compression fractures. In selecting appropriate patients for these procedures, it is important to distinguish the pain caused by a fracture from other causes of back pain. The purpose of this study was to determine the frequency of underlying, previously unrecognized malignant tumors in a consecutive series of patients undergoing kyphoplasty to treat vertebral compression fractures. Our hypothesis was that an unsuspected malignant tumor will exist and that a bone-marrow aspiration from the iliac crest would enhance our ability to detect a malignant tumor. METHODS: A prospective histological evaluation of vertebral body biopsy specimens from presumed osteoporotic vertebral compression fractures and a concurrent bone-marrow aspiration from the iliac crest were performed in order to identify latent hematopoietic dyscrasias. Over a four-year period, vertebral body biopsies from 523 vertebral levels as well as iliac crest bone-marrow aspirations were performed in 238 patients. Both specimens were evaluated histologically, and the prevalence of an underlying occult malignant neoplasm was determined. RESULTS: All specimens from the vertebral bodies showed signs of bone-remodeling and/or fracture-healing. However, in three patients, both the bone biopsy specimen and the bone-marrow aspirate showed evidence of B-cell lymphoma. The bone-marrow aspirate did not provide any additional information compared with the vertebral body biopsy specimen, and multiple myeloma was not identified in any patient. CONCLUSIONS: Lymphoma is an uncommon cause of a vertebral compression fracture, but on the basis of our experience in this series, we recommend that vertebral body biopsy specimens be obtained in all patients managed with kyphoplasty and vertebroplasty to rule out an unsuspected malignant tumor. However, we do not recommend the routine use of an additional bone-marrow aspiration from the iliac crest during vertebral augmentation procedures because doing so did not appear to enhance our ability to detect a malignant tumor.     

Preliminary outcomes and efficacy of the first 360 consecutive kyphoplasties for the treatment of painful osteoporotic vertebral compression fractures.

BACKGROUND CONTEXT: Osteoporosis is a major cause of morbidity in worldwide elderly populations. Patients may become susceptible to vertebral compression fractures (VCFs) from low-impact situations. For patients who have failed conventional, palliative medical therapy, kyphoplasty not only reduces pain associated with vertebral fractures, but also offers a minimally invasive procedure with the potential to address fracture reduction and spinal sagittal alignment. Kyphoplasty involves expanding an inflatable balloon tamp to create a cavity within a vertebral body before cement deposition. PURPOSE: To evaluate the safety and efficacy of kyphoplasty to reduce and fix painful osteoporotic VCFs. STUDY DESIGN/SETTING: A retrospective, single-arm cohort study of consecutive kyphoplasty patients treated at a single center. PATIENT SAMPLE: Three hundred sixty VCFs were treated during 254 kyphoplasty procedures on 222 osteoporotic patients (mean age, 76 years [range, 28-98]; 28% male and 72% female). OUTCOME MEASURES: Patient-reported pain ratings were examined. Cement extravasation was monitored by intraoperative fluoroscopy and on postoperative radiographs. Anterior and midline vertebral height were assessed from standing, lateral radiographs obtained preoperatively and postoperatively. The number of patients who returned with symptomatic, new fractures was monitored. Perioperative complications were recorded. Mean follow-up occurred 21 months after kyphoplasty (range, 6 months through 36 months). RESULTS: Immediate pain relief was reported by 89% of patients by the first follow-up visit. One patient experienced postoperative pain as a result of radiculopathy related to bone filler leakage into the foramen. The remaining patients had persistent pain and were diagnosed with either a new fracture or underlying degenerative disc disease. Greater than or equal to 20% restoration of lost vertebral height (anterior) was observed in 63% of fractures with an overall mean restoration of 30%, and > or = 20% restoration of lost vertebral height (midline) was detected in 69% of fractures with an overall mean restoration of 50%. In this cohort, 12% (30/254) of the patients required additional kyphoplasty procedures to treat 36 symptomatic, new adjacent and remote fractures. No device-related complications occurred. CONCLUSIONS: Kyphoplasty is a safe and effective, minimally invasive procedure for relief of pain associated with VCF. In our series we also demonstrated some restoration of vertebral height and partial correction of sagittal alignment.     

Kyphoplastik im konventionellen und halboffenen Verfahren

Kyphoplasty is a young method which was developed for the minimally invasive augmentation of osteoporotic vertebral fractures. In contrast to vertebroplasty, the kyphoplasty technique allows an age-dependent fracture reduction through the inflation of a special balloon in the fractured cancellous bone of the vertebral body. The cancellous bone of the fracture zone is compressed by the balloon, so that a cavity remains in the vertebral body after removing the balloon, which is filled with highly viscous augmentation material. The reduced risk of serious complications, for example epidural leakage of augmentation material, justifies progressively expanding the indications for this technique to traumatic fractures with involvement of the posterior vertebral wall and neoplastic vertebral collapse due to osteolytic metastasis. Besides the indications for the conventional percutaneous approaches, the microsurgical interlaminary approach allows the use of kyphoplasty in more complex fractures involving compression of the neural structures. Kyphoplasty induces swift pain relief and allows rapid mobilisation of patients due to the immediate stabilisation of the affected vertebral bodies. Apart from the operative intervention, the medical treatment of the primary disease and the rehabilitation of the individual patient should be optimised through an interdisciplinary approach.     

Initial outcome and efficacy of "kyphoplasty" in the treatment of painful osteoporotic vertebral compression fractures.

STUDY DESIGN: An Institutional Review Board-approved Phase I efficacy study of inflatable bone tamp usage in the treatment of symptomatic osteoporotic compression fractures. OBJECTIVES: To evaluate the safety and efficacy of inflatable bone tamp reduction and cement augmentation, "kyphoplasty," in the treatment of painful osteoporotic vertebral compression fractures. SUMMARY OF BACKGROUND DATA: Osteoporotic compression fractures can result in progressive kyphosis and chronic pain. Traditional treatment for these patients includes bed rest, analgesics, and bracing. Augmentation of vertebral compression fractures with polymethylmethacrylate, "vertebroplasty," has been used to treat pain. This technique, however, makes no attempt to restore the height of the collapsed vertebral body. Kyphoplasty is a new technique that involves the introduction of inflatable bone tamps into the vertebral body. Once inflated, the bone tamps restore the vertebral body back toward its original height while creating a cavity that can be filled with bone cement. PATIENTS AND METHODS: Seventy consecutive kyphoplasty procedures were performed in 30 patients. The indications included painful primary or secondary osteoporotic vertebral compression fractures. Mean duration of symptoms was 5.9 months. Symptomatic levels were identified by correlating the clinical data with MRI findings. Perioperative variables and bone tamp complications or issues were recorded and analyzed. Preoperative and postoperative radiographs were compared to calculate the percentage height restored. Outcome data were obtained by comparing preoperative and latest postoperative SF-36 data. RESULTS: At the completion of the Phase I study there were no major complications related directly to use of this technique or use of the inflatable bone tamp. In 70% of the vertebral bodies kyphoplasty restored 47% of the lost height. Cement leakage occurred at six levels (8.6%).SF-36 scores for Bodily Pain 11.6-58.7, (P = 0.0001) and Physical Function 11.7-47.4, (P = 0.002) were among those that showed significant improvement. CONCLUSIONS: The inflatable bone tamp was efficacious in the treatment of osteoporotic vertebral compression fractures. Kyphoplasty is associated with early clinical improvement of pain and function as well as restoration of vertebral body height in the treatment of painful osteoporotic compression fractures.     

Percutaneous vertebral body cement augmentation for back pain related to occult osteomyelitis/diskitis

Although complications related to vertebroplasty or kyphoplasty are few, we treated 2 patients with vertebroplasty or kyphoplasty for pain, presumed to be due to vertebral compression fractures, which were subsequently found to be due to occult osteomyelitis/diskitis. The onset of their infections appeared to have preceded their vertebral body augmentation procedures and was possibly due to prior interventional procedures for histories of back pain.An 86-year-old woman had had 3 prior kyphoplasty procedures for fractures at T10, T11, and L1. She reported continued severe pain, and subsequent magnetic resonance imaging was misinterpreted for another fracture at T12, resulting in her fourth kyphoplasty. She became septic and had some improvement with antibiotics, but she declined specialty care and died. A 74-year-old man with chronic back pain had recently undergone lumbar facet joint injections. Computed tomography and subsequent bone scan found uptake at both L2 and L3. Despite abnormal erythrocyte sedimentation rate and C-reactive protein level and normal radiographic vertebral height, he underwent a vertebroplasty. His pain increased, and subsequent workup found L2-3 diskitis. He recovered with antibiotics and specialty care. Similar to prior reports of spondylodiskitis, both patients had multiple medical comorbidities.This article emphasizes the need for clinical reevaluation and scrutiny in the interpretation of imaging studies, including for infection in patients with continued pain after spinal procedures. The differential diagnosis of infectious etiology is an important consideration prior to vertebral cement augmentation for presumed fragility fracture.     

Routine needle biopsy during vertebral augmentation procedures. Is it necessary?

Vertebral augmentation procedures are currently widely performed to treat vertebral compression fractures. The purpose of this study was to determine the frequency of underlying previously unrecognized etiology in a consecutive series of patients undergoing kyphoplasty to treat vertebral compression fractures. A prospective histological evaluation of vertebral body biopsy specimens from presumed osteoporotic vertebral compression fractures were performed in order to identify aforementioned causes. Over a 2-year period, vertebral body biopsies from 154 vertebral levels were performed in 75 patients undergoing kyphoplasty for vertebral compression fractures. All patients received a preoperative workup that included plain radiographs, MRI, whole body bone scan, and laboratory examinations. Bone specimens were obtained from affected vertebral bodies and submitted for histologic evaluation to identify the prevalence of an underlying cause. All specimens demonstrated fragmented bone with variable amounts of unmineralised bone, signs of bone-remodeling and/or fracture-healing. In 11 patients underlying pathology other than osteoporosis was identified (prostate cancer, 1; pancreatic cancer, 1; colon cancer, 1; breast cancer, 2; multiple myeloma, 3; leukemia, 1; and lung cancer, 2). In all but one patient the results of the biopsy confirmed the diagnosis suspected from the preoperative workup. For the last patient, namely the one with pancreatic cancer, the workup did not identify the origin of the primary tumor, although the patient was considered to have a compression fracture secondary to metastatic disease of unknown origin, the vertebral biopsy suggested the presence of adenocarcinoma which eventually was proven to be pancreatic cancer. In augmentation procedures for vertebral compression fractures, bone biopsy should be reserved for the patients where the preoperative evaluation raises the suspicion of a non-osteoporotic etiology.     

Percutaneous vertebral augmentation.

BACKGROUND CONTEXT: With the aging of the population, painful osteoporotic compression fractures are becoming more common. PURPOSE: To review the physiologic implications of these injuries as well as treatment options and outcomes, especially with reference to newer, percutaneous "augmentation" procedures, that is, vertebroplasty and kyphoplasty. STUDY DESIGN/SETTING: A literature review. METHODS: No direct, randomized studies comparing vertebroplasty, kyphoplasty and standard, nonoperative care are available. RESULTS: The growing literature suggests a role for kyphoplasty and vertebroplasty in the management of patients with intractable pain or progressive vertebral collapse after vertebral compression fracture. Both procedures likely offer similar rates of pain relief. Kyphoplasty, although more expensive, may allow fracture reduction. The void created with the balloon tamp allows a more viscous cement to be applied, thereby decreasing the risk of extravasation. CONCLUSIONS: More study is required to understand the ideal role of these new techniques in the management of spinal osteoporosis and associated fractures. However, for carefully selected cases, current data suggest that the complication rates are low and pain relief can be profound.     

Combined percutaneous transpedicular tumor debulking and kyphoplasty for pathological compression fractures. Technical note

Percutaneous balloon kyphoplasty has become a widely adopted treatment option for patients with pain due to pathological compression fractures. One potential risk of the procedure is the displacement of tumor into the spinal canal and resulting spinal cord or cauda equina injury during inflation of the balloon prior to polymethylmethacrylate (PMMA) placement. In addition, the presence of any remaining tumor between the PMMA and the fractured cortical bone can lead to suboptimal improvement in stabilization and subsequent pain relief. The authors describe a technique to remove tumor from within the vertebral body (VB) through a percutaneous working channel prior to kyphoplasty balloon inflation and augmentation. The technique was successfully used in all three patients who had presented with pain, and the pain improved in all three cases. There was no extravasation of PMMA into the spinal canal in any case. A combined VB tumor debulking and kyphoplasty technique offers the ability to improve the placement of PMMA within the diseased vertebral body, potentially leading to increased safety as well as clinical effectiveness for stabilization of these fractures.     

Spinal loads after osteoporotic vertebral fractures treated by vertebroplasty or kyphoplasty

Vertebroplasty and kyphoplasty are routine treatments for compression fractures of vertebral bodies. A wedge-shaped compression fracture shifts the centre of gravity of the upper body anteriorly and generally, this shift can be compensated in the spine and in the hips. However, it is still unclear how a wedge-shaped compression fracture of a vertebra increases forces in the trunk muscle and the intradiscal pressure in the adjacent discs. A nonlinear finite element model of the lumbar spine was used to estimate the force in the trunk muscle, the intradiscal pressure and the stresses in the endplates in the intact spine, and after vertebroplasty and kyphoplasty treatment. In this study, kyphoplasty represents a treatment with nearly full fracture reduction and vertebroplasty one without restoration of kyphotic angle although in reality kyphoplasty does not guarantee fracture reduction. If no compensation of upper body shift is assumed, the force in the erector spine increases by about 200% for the vertebroplasty but by only 55% for the kyphoplasty compared to the intact spine. Intradiscal pressure increases by about 60 and 20% for the vertebroplasty and kyphoplasty, respectively. In contrast, with shift compensation of the upper body, the increase in muscle force is much lower and increase in intradiscal pressure is only about 20 and 7.5% for the vertebroplasty and kyphoplasty, respectively. Augmentation of the vertebral body with bone cement has a much smaller effect on intradiscal pressure. The increase in that case is only about 2.4% for the intact as well as for the fractured vertebra. Moreover, the effect of upper body shift after a wedge-shaped vertebral body fracture on intradiscal pressure and thus on spinal load is much more pronounced than that of stiffness increase due to cement infiltration. Maximum von Mises stress in the endplates of all lumbar vertebrae is also higher after kyphoplasty and vertebroplasty. Cement augmentation has only a minor effect on endplate stresses in the unfractured vertebrae. The advantages of kyphoplasty found in this study will be apparent only if nearly full fracture reduction is achieved. Otherwise, differences between kyphoplasty and vertebroplasty become small or vanish. Our results suggest that vertebral body fractures in the adjacent vertebrae after vertebroplasty or kyphoplasty are not induced by the elevated stiffness of the treated vertebra, but instead the anterior shift of the upper body is the dominating factor.     

Extended kyphoplasty indications for stabilization of osteoporotic vertebral compression fractures

OBJECTIVES: Percutaneous vertebroplasty with polymethylmethacrylate allows minimally invasive stabilization of osteoporotic vertebral fractures. Fracture reduction is, however, not possible and the risk of uncontrolled epidural cement leakage with burst fractures is increased. Kyphoplasty, in contrast, allows a degree of fracture reduction and provides an extended spectrum of indications through open approaches, which enable spinal decompression and augmentation of incomplete burst fractures. METHODS. In kyphoplasty a contrast-filled balloon is inflated in the vertebra until a cavern is created. A degree of reposition may be achieved depending on fracture age. Augmentation is performed with high-viscosity polymethylmethacrylate under low pressure. In cases of neural compression, interlaminary spinal decompression and kyphoplasty through the posterior wall is performed. With anterior spinal procedures, kyphoplasty can be performed without extending the approach. RESULTS: Vertebral augmentation was performed by percutaneous, interlaminary, and anterior approaches for incomplete burst fractures. Four representative cases are presented from a collective of 120 augmentations. CONCLUSIONS: Percutaneous kyphoplasty, supplemented by open approaches, enables augmentation of osteoporotic incomplete burst fractures.     

骨质疏松性椎体压缩性骨折椎体强化术后再骨折相关因素研究

目的探讨骨质疏松性椎体骨折椎体强化术(椎体成形PVP和椎体后凸成形PKP)术后椎体再骨折发生的临床特点和危险因素。方法回顾性分析2008年8月～2011年8月在我院行经皮椎体强化术的171例患者,其中再发椎体骨折19例27个椎体(A组),未再发骨折152例作为对照(B组)。所有患者获得随访6～16个月,平均13个月。记录患者临床资料、骨水泥注入量、测量椎体前缘椎体高度及Cobb角变化等并进行多因素Logistic回归分析;记录再次手术前、后第1天及末次随访VAS评分。结果 16个椎体发生在PVP术后相邻椎体(84.2%),其中9个椎体术后2个月内发生;骨水泥向椎间盘渗漏在A、B组间有显著性差异(P<0.05);椎体强化术在再骨折术前、后VAS评分有显著性差异(P<0.05)。结论骨质疏松性椎体再骨折发生具有一定危险因素,椎体强化术可以取得满意的治疗效果,同时应该加强骨质疏松药物治疗。