Study design Literature review Objectives To describe new treatments for painful osteoporotic compression fractures in light of available scientific literature and clinical experience Summary of background data Painful vertebral osteoporotic compression fractures lead to significant morbidity and mortality This relates to pulmonary dysfunction, eating disorders (nutritional deficits), pain, loss of independence, and mental status change (related to pain and medications) Medications to treat osteoporosis (primarily antiresorptive) do not effectively treat the pain or the fracture, and require over 1 year to reduce the degree of osteoporosis Kyphoplasty and vertebroplasty are new techniques that help decrease the pain and improve function in fractured vertebrae Methods This is a descriptive review of the background leading to vertebroplasty and kyphoplasty, a description of the techniques, a review of the literature, as well as current ongoing studies evaluating kyphoplasty Results Both techniques have had a very high acceptance and use rate There is 95% improvement in pain and significant improvement in function following treatment by either of these percutaneous techniques Kyphoplasty improves height of the fractured vertebra, and improves kyphosis by over 50%, if performed within 3 months from the onset of the fracture (onset of pain) There is some height improvement, though not as marked, along with 95% clinical improvement, if the procedure is performed after 3 months Complications occur with both and relate to cement leakage in both, and cement emboli with vertebroplasty Conclusion Kyphoplasty and vertebroplasty are safe and effective, and have a useful role in the treatment of painful osteoporotic vertebral compression fractures that do not respond to conventional treatments Kyphoplasty offers the additional advantage of realigning the spinal column and regaining height of the fractured vertebra, which may help decrease the pulmonary, GI, and early morbidity consequences related to these fractures Both procedures are technically demanding

New technologies in spine: kyphoplasty and vertebroplasty for the treatment of painful osteoporotic compression fractures.

Transpedicular vertebroplasty for the treatment of compression fractures of the thoracic and lumbar spine has been well described, and the reported complication rates are low. In this paper we present two cases of patients treated with vertebroplasty despite a history of prior infection. Osteomyelitis and abscess developed in these patients and they underwent corpectomy with anterior reconstruction and posterior stabilization. Great care should be taken when using vertebroplasty to treat patients who have a history of infection, because they may suffer osteomyelitis.

Report of two cases and review of the literature

Objective. To assess the immediate and long-term efficacy and safety of percutaneous vertebroplasty with polymethylmethacrylate (PMMA) for the treatment of refractory pain resulting from osteoporotic vertebral fractures. Methods. A retrospective, open study of percutaneous vertebroplasty (PV) was conducted with long-term follow-up. PV with PMMA was carried out between 1990 and 1996 in 40 patients with symptomatic osteoporotic vertebral fracture(s) that had not responded to maximum medical therapy. In 1997, each patient was asked to come back to our institution for a physical and spinal X-ray examination. Efficacy was assessed by changes over time in pain on Huskisson's visual analogue scale (VAS). Results. Thirty-four vertebrae treated by PV in 25 patients were evaluated with long-term follow-up. The mean duration of follow-up was 48 months (range 12-84 months). Pain assessed by the VAS significantly (P < 0.05) decreased from a mean of 80 mm ± 16 (S.D.) before PV to 37 ± 24 mm after 1 month and 34 ± 28 mm at the time of maximal follow-up. There was no severe complication related to this treatment, and no progression of vertebral deformity in any of the injected vertebrae. However, there was a slight but significantly increased risk of vertebral fracture in the vicinity of a cemented vertebra (odds ratio 2.27, 95% confidence interval 1.1-4.56). The odds ratio of a vertebral fracture in the vicinity of an uncemented fractured vertebra was 1.44 (0.82-2.55). Conclusion. PV appears to be a safe and useful procedure for the treatment of focal back pain secondary to osteoporotic vertebral fracture when conservative treatment has failed.

Long‐term observations of vertebral osteoporotic fractures treated by percutaneous vertebroplasty

The disclosure relates to devices and methods for implantation of an orthopedic device between skeletal segments using limited surgical dissection. The implanted devices are used to adjust and maintain the spatial relationship(s) of adjacent bones. Depending on the implant design, the motion between the skeletal segments may be increased, limited, modified, or completely immobilized.

Devices and methods for inter-vertebral orthopedic device placement

Object The current North American experience with minimally invasive vertebro- and kyphoplasty is largely limited to the treatment of benign osteoporotic compression fractures. The objective of this study was to assess the safety and efficacy of these procedures for painful vertebral body (VB) fractures in cancer patients. Methods The authors reviewed a consecutive group of cancer patients (21 with myeloma and 35 with other primary malignancies) undergoing vertebro- and kyphoplasty at their institution. Ninety-seven (65 vertebro- and 32 kyphoplasty) procedures were performed in 56 patients during 58 treatment sessions. The mean patient age was 62 years (+/- 13 years [standard deviation]) and the median duration of symptoms was 3.2 months. All patients suffered intractable spinal pain secondary to VB fractures. Patients noted marked or complete pain relief after 49 procedures (84%), and no change after five procedures (9%); early postoperative Visual Analog Scale (VAS) pain scores were unavailable in four patients (7%). No patient was worse after treatment. Reductions in VAS pain scores remained significant up to 1 year (p = 0.02, Wilcoxon signed-rank test). Analgesic consumption was reduced at 1 month (p = 0.03, Wilcoxon signed-rank test). Median follow-up length was 4.5 months (range 1 day-19.7 months). Asymptomatic cement leakage occurred during vertebroplasty at six (9.2%) of 65 levels; no cement extravasation was seen during kyphoplasty. There were no deaths or complications related to the procedures. The mean percentage of restored VB height by kyphoplasty was 42 +/- 21%. Conclusions Percutaneous vertebro- and kyphoplasty provided significant pain relief in a high percentage of patients, and this appeared durable over time. The absence of cement leakage-related complications may reflect the use of 1) high-viscosity cement; 2) kyphoplasty in selected cases; and 3) relatively small volume injection. Precise indications for these techniques are evolving; however, they are safe and feasible in well-selected patients with refractory spinal pain due to myeloma bone disease or metastases.

Percutaneous vertebroplasty and kyphoplasty for painful vertebral body fractures in cancer patients

Study Design. Ex vivo biomechanical study using osreoporotic cadavetic vertebral bodies. Objective. To determine the association between the volume of compent injected during percutaneous vertebroplasty and the restoration of strength and stiffness in osteoporotic vertebral bodies, two investigational cements were studied: Orthocomp (Orthovita, Malvern, PA) and Simplex 20 (Simplex P with 20% by weight barium sulfate content: Stryker-Howmedica-Osteonics, Rutherford, NJ). Summary of Background Data. Previous biomechanical studies have shown that injections of 8-10 mL of cement during vertebroplasty restore or increase vertebral body strength and stiffness; however, the doseresponse association between cement volume and restoration of strength and stiffness is unknown. Methods. Compression fractures were experimentally created in 144 vertebral bodies (T6-L5) obtained from 12 osteoporotic spines harvested from female cadavers. After initial strength and stiffness were determined, the vertebral bodies were stabilized using bipedicular injections of cement totaling 2, 4, 6, or 8 mL and recompressed, after which post-treatment strength and stiffness were measured. Strength and stiffness were considered restored when post-treatment values were not significantly different from initial values. Results. Strength was restored for all regions when 2 mL of either cement was injected. To restore stiffness with Orthocomp, the thoracic and thoracolumbar regions required 4 mL, but the lumbar region required 6 mL. To restore stiffness with Simplex 20, the thoracic and lumbar regions required 4 mL, but the thoracolumbar region required 8 mL. Conclusion. These data provide guidance on the cement volumes needed to restore biomechanical integrity to compressed osteoporotic vertebral bodies.

The biomechanics of vertebroplasty. The effect of cement volume on mechanical behavior.

Acrylic cements have been used for the augmentation of weakened or partially destroyed bones for decades [(1)][1]. The term vertebroplasty originally described an open surgical procedure that introduces bone graft or acrylic cement to mechanically augment weakened vertebral bodies.

http://www.ajnr.org/content/ajnr/22/2/373.full.pdf

Percutaneous vertebroplasty : a developing standard of care for vertebral compression fractures

Temperature elevation caused by bone cement polymerization during vertebroplasty.

Study design Cadaveric study on the biomechanics of osteoporotic vertebral bodies augmented and not augmented with polymethylmethacrylate cement. Objectives To determine the strength and stiffness of osteoporotic vertebral bodies subjected to compression fractures and 1) not augmented, 2) augmented with unipedicular injection of cement, or 3) augmented with bipedicular injection of cement. Summary of background data Percutaneous vertebroplasty is a relatively new method of managing osteoporotic compression fractures, but it lacks biomechanical confirmation. Methods Fresh vertebral bodies (L2-L5) were harvested from 10 osteoporotic spines (T scores range, -3.7 to -8.8) and compressed in a materials testing machine to determine intact strength and stiffness. They were then repaired using a transpedicular injection of cement (unipedicular or bipedicular), or they were unaugmented and recrushed. Results Results suggest that unipedicular and bipedicular cement injection restored vertebral body stiffness to intact values, whereas unaugmented vertebral bodies were significantly more compliant than either injected or intact vertebral bodies. Vertebral bodies injected with cement (both bipedicular and unipedicular) were significantly stronger than the intact vertebral bodies, whereas unaugmented vertebral bodies were significantly weaker. There was no significant difference in loss in vertebral body height between any of the augmentation groups. Conclusions This study suggests that unipedicular and bipedicular injection of cement, as used during percutaneous vertebroplasty, increases acute strength and restores stiffness of vertebral bodies with compression fractures.

Biomechanical efficacy of unipedicular versus bipedicular vertebroplasty for the management of osteoporotic compression fractures.

of compression fracture. Methods. Compression fractures were experimentally created in 16 osteoporotic VBs assigned to either the tamp or percutaneous vertebroplasty group. The tamp treatment consisted of inserting balloon-like devices into the vertebral body, inflating the bone tamp, and filling the void with Simplex P (Howmedica, Rutherford, NJ) bone cement. The percutaneous vertebroplasty treatment consisted of directly injecting Cranioplastic bone cement (CMW, Blackpool, UK) into the vertebral body. Pre- and posttreatment heights were measured, and the repaired vertebral bodies were recompressed to determine posttreatment strength and stiffness values. Results. The tamp treatment resulted in significant restoration (97%) of vertebral body height lost after compression, whereas percutaneous vertebroplasty treatment resulted in a significantly lower restoration of lost height (30%) (P , 0.05). Both treatments resulted in significantly stronger vertebral bodies relative to their initial state (P , 0.05). The tamp treatment restored vertebral body stiffness to initial values, but the percutaneous vertebroplasty treatment did not (P , 0.05). Conclusions. Tamp treatment resulted in significantly greater height restoration than did percutaneous vertebroplasty, without loss of vertebral body strength or stiff

Stephen M. Belkoff

Papers

The biomechanics of vertebroplasty. The effect of cement volume on mechanical behavior.

Percutaneous vertebroplasty : a developing standard of care for vertebral compression fractures

Temperature elevation caused by bone cement polymerization during vertebroplasty.

Biomechanical efficacy of unipedicular versus bipedicular vertebroplasty for the management of osteoporotic compression fractures.

An ex vivo biomechanical evaluation of an inflatable bone tamp used in the treatment of compression fracture.