A prospective randomized FDA-IDE trial comparing Cortoss with PMMA for vertebroplasty: a comparative effectiveness research study with 24-month follow-up.

STUDY DESIGN: Randomized, controlled, prospective (AAOS therapeutic level I) trial conducted under Food and Drug Administration Investigational Device Exemption hypothesized noninferiority of a novel bioactive composite material to polymethylmethacrylate (PMMA). OBJECTIVE: To determine the safety and efficacy of a new, nonresorbable bioactive composite (Cortoss) compared with PMMA, the standard treatment of vertebral compression fractures (VCFs). SUMMARY OF BACKGROUND DATA: Vertebroplasty with PMMA, the widely adopted treatment for VCFs nonresponsive to conservative care, provides effective, immediate pain relief, but the material has received criticism for its properties. A new bioactive composite material designed specifically for vertebroplasty showed promising results in animals and nonrandomized clinical studies and was subsequently compared with PMMA in a randomized study. This study represents the first prospective study evaluating vertebroplasty comparing PMMA with another material with 24-month follow-up. METHODS: Using 2:1 randomization, vertebroplasty was performed with Cortoss on 162 patients and PMMA on 94 patients. Inclusion criteria were painful osteoporotic VCFs with a visual analogue scale pain score of at least 50 mm on a 100-mm scale and at least 30% disability as measured by the Oswestry Disability Index. Evaluations at pretreatment, treatment day, and 7 posttreatment intervals out to 24 months included pain, disability, neurological status, adverse events, quality of life, patient satisfaction, analgesic use, and independently reviewed radiographs. RESULTS: Noninferiority of Cortoss relative to PMMA was observed, with Cortoss-treated patients experiencing significant pain relief at 3 months (P = 0.0395) and better maintenance or improvement in function at 24 months (P = 0.0299). Incidence of serious device-related adverse events was 4.3% in both groups; none were life threatening. CONCLUSION: Vertebroplasty using either Cortoss or PMMA provides effective, immediate, and lasting pain relief and prevents further loss of function. Both materials performed comparably at most time points; Cortoss demonstrated better results for pain reduction at 3 months and for function at 24 months.

Vertebral body reconstruction: techniques and tools.

Vertebral augmentation techniques use image guidance for the percutaneous placement of spinal implants that stabilize a painful osteoporotic or pathologic vertebral compression fracture. The initial implant, acrylic bone cement, was injected through a bone needle into the vertebral body, a procedure referred to as vertebroplasty. A modification of this procedure, kyphoplasty, entails the temporary use of an inflatable balloon tamp before cement injection. Other techniques and the equipment required to perform these vertebral augmentation procedures have evolved significantly during the past two decades. It is now possible to perform vertebral body reconstruction in patients with painful fractures of compromised vertebrae with excellent outcomes in terms of sustainable pain relief and marked reduction in patient morbidity.

Sacral fractures and sacroplasty.

Pain from sacral insufficiency fractures or metastatic tumor to the sacrum, refractory to radiation and/or chemotherapy, can be extremely debilitating to affected patients. Conservative medical therapy with rest, limited ambulation, and pain medication has been the mainstay of treatment. Open surgical fixation is reserved for severe fracture that does not heal with rest. A minimally invasive treatment, sacroplasty, is gaining popularity and uses image-guided, percutaneous injection of surgical cement into the fracture. This article reviews the incidence, causes, diagnosis, presentation, and treatment options for sacral fractures, and describes detailed technical steps of the sacroplasty procedure.

Percutaneous therapy for symptomatic synovial cysts.

Synovial cysts have long been known to create radicular pain in the spine, with the clinical effect mimicking a disk herniation. These cysts have traditionally been treated with open surgical therapy. Now a minimally invasive, image-guided approach to treatment is available to relieve this problem, using a simple percutaneous needle stick and injection. This article describes the technical aspects and precautions needed for this intervention.

Epidural steroid injections.

Epidural steroid injections have been used for decades as part of a rehabilitation program to relieve back or neck pain and the associated radicular nerve component that often accompanies these problems. These injections are minimally invasive and offer many patients substantial relief without the need for more invasive procedures. Although effective and generally simple, they must be performed accurately and properly for maximum benefit and complication avoidance. This article discusses the various technical aspects of the procedure that must be observed by the operator to accomplish these ends.

Pharmaceuticals used in image-guided spine interventions.

As image-guided (nonvascular) spine interventions have become progressively more common in the interventional radiologic community, there is a growing need for physician expertise regarding the materials and pharmaceuticals that are used for these procedures. This article is intended to provide information to address these needs.

A biomechanical comparison of lateral and posterior approaches to sacroplasty.

STUDY DESIGN: Biomechanical cadaveric bench study. OBJECTIVE: To measure the augmentation effect and extravasation risk of posterior and lateral approaches to sacroplasty. SUMMARY OF BACKGROUND DATA: The biomechanical stabilizing effect of sacroplasty is unknown. METHODS: Using a sacral insufficiency fracture model, we performed sacroplasty in 15 osteoporotic cadaveric pelves. Five served as controls, and 10 were each injected with 4 mL of a polymethylmethacrylate cement (5 via a posterior approach, 5 via a lateral approach). Cement extravasation was assessed using computed tomography. Restored strength and stiffness were defined as the ratios of treatment to initial strength and to stiffness, respectively. Between-group differences in restoration parameters were checked for significance (P < 0.05) using an analysis of variance followed by Tukey's test. RESULTS: We found no significant differences between groups in terms of restored strength ( approximately 61%) and stiffness ( approximately 77%). Both injection methods produced extravasation into the anterior sacrum, the posterior sacrum, the sacroiliac joint, and the neural foramens. CONCLUSION: Sacroplasty with 4 mL of cement does not restore the strength or stiffness of the sacrum in a cadaveric model, regardless of the approach used.

The strength of the osteoporotic sacrum.

STUDY DESIGN: Biomechanical cadaveric bench study. OBJECTIVE: To determine the strength of the osteoporotic sacrum subjected to vertical force. SUMMARY OF BACKGROUND DATA: Sacral insufficiency fractures are thought to be caused by vertical shear forces acting in the sacral ala. The force required to fracture the osteoporotic sacrum is unknown. METHODS: Eighteen osteoporotic cadaveric pelves were potted and mounted on a materials testing machine so that the anterior superior spine was aligned with the symphysis in the sagittal plane. The lumbar spine (L3-L4) was displaced vertically downward until failure occurred. Failure loads were recorded, and fracture patterns were identified via computed tomography. RESULTS: Mean (+/-SD) failure load was 3200 +/- 1262 N. In 3 of 18 specimens, sacral fractures were not apparent on computed tomography. In 15 of 18 specimens, fractures were produced lateral to the neural foramina. Of those 15 specimens, 8 were unilateral (1 with horizontal extension) and 7 were bilateral. In 13 of 15 cases, fractures were located in Denis Zone 1. CONCLUSION: The osteoporotic sacrum failed under vertical forces of approximately 4.5 times body weight. Imaged fracture patterns resembled sacral insufficiency fractures seen clinically. In 1 case, a horizontal fracture line was produced. Vertical compression forces appear to cause insufficiency fractures in the osteoporotic sacrum.

Vertebroplasty and kyphoplasty: techniques for avoiding complications and pitfalls.

The purpose of this article is to present a series of common complications and pitfalls associated with vertebroplasty and kyphoplasty, with discussions on how to avoid those problems in a practical, case-based essay.

Vertebroplasty and kyphoplasty: rapid pain relief for vertebral compression fractures.

Vertebroplasty and kyphoplasty are minimally invasive procedures aimed at relieving symptoms associated with vertebral compression fractures. They have become accepted, highly effective, safe procedures, and are known for their high patient satisfaction rates. Although they are image-guided percutaneous spine therapies, differences do exist. They have each arisen from different backgrounds and are championed by different subspecialties and each involves slightly different techniques. In addition, a prospective, randomized trial comparing the two techniques has yet to be performed. This lack of objective data allows market forces and opinions to have a large influence on utilization and patient referral.

Percutaneous vertebroplasty: technical considerations.

Percutaneous vertebroplasty has now been in use in the United States for 10 years. Standards of practice are available from the American College of Radiology. The performance of this procedure is becoming routine for most interventional practices, and it has become the general standard of care for pain associated with vertebral compression fractures of the spine. This article describes routine procedural technique and considerations and is intended to review the authors' knowledge of the procedure and provide reliable methods for good outcomes and complication avoidance.

The effect of vertebral body percentage fill on mechanical behavior during percutaneous vertebroplasty.

STUDY DESIGN: An ex vivo biomechanical study was conducted using osteoporotic cadaveric vertebral bodies. OBJECTIVE: To determine the relationship between the percentage of osteoporotic vertebral body volume filled with polymethylmethacrylate cement during percutaneous vertebroplasty and the percentage restoration of strength and stiffness. SUMMARY OF BACKGROUND DATA: A previous biomechanical study reported a weak relationship between the volume of cement injected and restoration of vertebral body strength and stiffness. Vertebral bodies vary considerably in size among regions and among spines, and the weak correlation may be attributed to the fact that the volume of vertebral bodies was not explicitly considered. METHODS: The volume of 120 vertebral bodies (T6-L5) harvested from 10 osteoporotic female cadaver spines was determined by Archimedean displacement. Compression fractures were experimentally created, and initial strength and stiffness were determined. The vertebral bodies were stabilized using bipedicular injections of 2-8 mL of cement and then recompressed, after which posttreatment strength and stiffness were measured. Linear regression was used to analyze the relationship between percentage of volume fill and percentage of restored stiffness and strength. RESULTS: The correlations between percentage of fill and restored strength and stiffness were weak: r2 = 0.21 and r2 = 0.27, respectively. On average, restoration of strength and stiffness required vertebral body cement fills of 16.2% and 29.8%, respectively. CONCLUSION: Strength and stiffness are weakly correlated with the percentage fill volume of cement injected during vertebroplasty.

Ex vivo biomechanical comparison of hydroxyapatite and polymethylmethacrylate cements for use with vertebroplasty.

BACKGROUND AND PURPOSE: Little is known about the mechanical stabilization afforded by new materials proposed for use with vertebroplasty. This comparative ex vivo biomechanical study was designed to determine the strength and stiffness of osteoporotic vertebral bodies (VBs) subjected to compression fractures and stabilized with bipedicular injections of Cranioplastic altered in a manner consistent with the practice of vertebroplasty or BoneSource cement. METHODS: VBs T8-T10 and L2-L4 from 10 fresh spines were harvested from female cadavers (aged 91.5 years +/- 3.9 at death). These were screened for bone density (t score, -4.9 +/- 1.4; bone mineral density, 0.61 g/cm(2) +/- 0.19), disarticulated, and compressed to determine initial strength and stiffness. The fractured VBs were stabilized with bipedicular injections of a predetermined quantity and type of cement and then re-crushed. RESULTS: At both the thoracic and lumbar levels, VBs repaired with altered Cranioplastic resulted in significantly greater strength (P <.05) than that in their prefracture states, whereas those repaired with BoneSource were restored to their initial strength. Cranioplastic resulted in significantly stronger repairs than BoneSource in the thoracic region; however, repair strengths in the lumbar region were not significantly different. The repaired stiffness was significantly lower than the initial stiffness in all treatments and in both regions. Differences in the repaired stiffness between the treatment groups in either region and differences in the mechanical parameters obtained by adding an additional 2 mL of BoneSource were not significant. CONCLUSION: Both materials in the volumes used either restored or increased VB strength, but none restored stiffness.