Biomechanical comparison of kyphoplasty versus a titanium mesh implant with cement for stabilization of vertebral compression fractures

A novel device with pedicular anchorage provides better biomechanical properties than balloon kyphoplasty for the treatment of vertebral compression fractures

PURPOSE

To compare the biomechanical behavior of vertebrae with vertebral compression fractures (VCF) treated by a novel system with pedicular anchorage (dowelplasty) versus balloon kyphoplasty.

METHODS

Four cadaveric spines (T12-L5) were harvested, cleaned from soft tissues, and separated into vertebrae. Axial compressive loads were applied to each vertebra until a VCF was generated. Half of the vertebrae (n = 11) were instrumented using the "dowelplasty" system, consisting of a hollow titanium dowel anchored into the pedicle, through which a cannulated titanium nail is inserted and locked and through which cement is injected. The other half (n = 11) were instrumented using balloon kyphoplasty. Axial compressive loads were re-applied to each vertebra until fracture. Fracture load and fracture energy were calculated from load-displacement data for the pre- and post-treatment states.

RESULTS

Compared to balloon kyphoplasty, dowelplasty granted greater net change in fracture load (373N; 95%CI,-331-1076N) and fracture energy (755Nmm; 95%CI,-563-2072Nmm). A sensitivity analysis was performed without L4 and L5 vertebrae from the dowelplasty group, since the length of the cannulated nails was too short for these vertebrae: compared to balloon kyphoplasty, dowelplasty granted an even greater net change in fracture load (680N; 95%CI,-96-1457N) and fracture energy (1274Nmm; 95%CI,-233-2781Nmm).

CONCLUSION

Treating VCFs with dowelplasty grants increased fracture load and fracture energy compared to the pre-treatment state. Furthermore, dowelplasty grants greater improvement in fracture load and fracture energy compared to balloon kyphoplasty, which suggests that dowelplasty may be a good alternative for the treatment of VCF.

LEVEL OF EVIDENCE

level IV.

Innovative minimally invasive implants for osteoporosis vertebral compression fractures

With increasing population aging, osteoporosis vertebral compression fractures (OVCFs), resulting in severe back pain and functional impairment, have become progressively common. Percutaneous vertebroplasty (PVP) and percutaneous kyphoplasty (PKP) as minimally invasive procedures have revolutionized OVCFs treatment. However, PVP- and PKP-related complications, such as symptomatic cement leakage and adjacent vertebral fractures, continue to plague physicians. Consequently, progressively more implants for OVCFs have been developed recently to overcome the shortcomings of traditional procedures. Therefore, we conducted a literature review on several new implants for OVCFs, including StaXx FX, Vertebral Body Stenting, Vesselplasty, Sky Bone Expander, Kiva, Spine Jack, Osseofix, Optimesh, Jack, and V-strut. Additionally, this review highlights the individualized applications of these implants for OVCFs. Nevertheless, current clinical studies on these innovative implants remain limited. Future prospective, randomized, and controlled studies are needed to elucidate the effectiveness and indications of these new implants for OVCFs.

A Preliminary Study on the Morphological Changes of an NiTi-Shaped Memory Alloy Stent in the Vertebral Body

OBJECTIVE

At present, the most commonly used filler polymethyl methacrylate (PMMA) has the disadvantages of monomer toxicity, heat and leakage, and cannot be applied in young people. Therefore, finding a minimally invasive and good tissue-compatible alternative material has been a research hotspot in spine surgery in recent years. The aim of this study is to explore whether the memory alloy stent can avoid the complications of bone cement or not.

METHODS

Four non-adjacent vertebral bodies of the thoracic and lumbar spine in the 18 10-month-old pigs were selected as the surgical site and were randomly divided into the scaffold group and the bone cement group. The memory alloy scaffold and PMMA (polymethyl methacrylate) bone cement were placed via percutaneous puncture, and intraoperative fluoroscopy and micro-CT were used to observe the changes in the height of scaffolds and bone cement in the vertebral body immediately, 6 weeks, and 12 weeks after operation, the microstructural parameters of the bone trabeculae (bone volume fraction, bone surface volume ratio, bone trabeculae number) were also measured.

RESULTS

The memory alloy stent could expand in the vertebral body, and its height gradually increased with time; additionally, the height of the bone cement mass did not change with time (p = 0.00). New bone trabeculae could grow into the scaffold along the gap, and the volume fraction of bone, the volume ratio of bone surface area, and the number of bone trabeculae increased gradually (p = 0.00). However, the volume fraction of bone, the volume ratio of bone surface area, and the number of trabeculae in the cement block decreased gradually (p = 0.00).

CONCLUSIONS

Memory alloy scaffolds have dynamic expansion characteristics in vivo, which can effectively avoid the complications of bone cement. Thus, it is beneficial to explore this minimally invasive treatment for vertebral compression fractures.

Three generations of treatments for osteoporotic vertebral fractures: what is the evidence?

The management of vertebral compression fractures (VCFs) is based on conservative treatment and minimally invasive vertebral augmentation procedures. However, the role of vertebral augmentation is now being questioned by clinical trials and extensive studies. The aim of this review is to report the most relevant evidences on effectiveness, safety, and indications of the currently available vertebral augmentation techniques. Conservative treatment with bracing is effective in reducing acute but it has no effect on segmental kyphosis progression and pseudoarthrosis can occur. Percutaneous vertebroplasty (PV) was the first vertebral augmentation technique to be proposed for the treatment of VCFs. Two blinded and randomized clinical trials compared PV to a sham procedure and no significant differences in terms of efficacy were reported. More recent studies have suggested that PV can still benefit patients with acute VCFs and severe pain at onset. Balloon kyphoplasty (BK) was developed to improve the segmental alignment restoring the height of collapsed vertebrae. BK allows similar pain relief and disability improvement, as well as greater kyphosis correction compared to PV, moreover BKP seems to reduce cement leakage. Vertebral body stenting (VBS) and the KIVA system are third generation techniques of vertebral augmentation. VBS aims to increase the effectiveness in restoring the segmental alignment, while the KIVA system can prevent cement leakage. These techniques are effective and safe, even if their superiority to BK has yet to be proven by studies with a high level of evidence.

A 20-Year Review of Biomechanical Experimental Studies on Spine Implants Used for Percutaneous Surgical Repair of Vertebral Compression Fractures

A vertebral compression fracture (VCF) is an injury to a vertebra of the spine affecting the cortical walls and/or middle cancellous section. The most common risk factor for a VCF is osteoporosis, thus predisposing the elderly and postmenopausal women to this injury. Clinical consequences include loss of vertebral height, kyphotic deformity, altered stance, back pain, reduced mobility, reduced abdominal space, and reduced thoracic space, as well as early mortality. To restore vertebral mechanical stability, overall spine function, and patient quality of life, the original percutaneous surgical intervention has been vertebroplasty, whereby bone cement is injected into the affected vertebra. Because vertebroplasty cannot fully restore vertebral height, newer surgical techniques have been developed, such as kyphoplasty, stents, jacks, coils, and cubes. But, relatively few studies have experimentally assessed the biomechanical performance of these newer procedures. This article reviews over 20 years of scientific literature that has experimentally evaluated the biomechanics of percutaneous VCF repair methods. Specifically, this article describes the basic operating principles of the repair methods, the study protocols used to experimentally assess their biomechanical performance, and the actual biomechanical data measured, as well as giving a number of recommendations for future research directions.

Therapeutic Efficacy of Third-Generation Percutaneous Vertebral Augmentation System (PVAS) in Osteoporotic Vertebral Compression Fractures (OVCFs): A Systematic Review and Meta-analysis

Purpose

This study aimed to assess whether the third-generation PVAS was superior to percutaneous vertebroplasty (PVP) or percutaneous kyphoplasty (PKP) in treating patients with OVCFs.

Methods

Databases, including Pubmed, Embase, and Cochrane library, were searched to identify relevant interventional and observational articles in vivo or in vitro comparing the third-generation PVAS to PVP/PKP in OVCFs patients. A meta-analysis was performed under the guidelines of the Cochrane Reviewer's Handbook.

Results

11 in vivo articles involving 1035 patients with 1320 segments of diseased vertebral bodies and 8 in vitro studies enrolling 40 specimens with 202 vertebral bodies were identified. The vivo studies indicated no significant differences were found in visual analog scale (VAS), Oswestry Disability Index (ODI), operation time, or injected cement volume (P > 0.05). The third-generation PVAS was associated with significant improvement in vertebral height and Cobb angle (P < 0.05) and also with a significantly lower risk of cement leakages and new fractures (P < 0.05). The vitro studies suggest that the third-generation PVAS was associated with better anterior vertebral height (AVH) and kyphotic angle (KA) after deflation and cement. No significant differences were found in stiffness or failure load after cement between the two groups (P > 0.05).

Conclusion

Based on current evidence, although providing similar improvement in VAS and ODI, the third-generation PVAS may be superior to PVP/PKP in local kyphosis correction, vertebral height maintenance, and adverse events reduction. Further high-quality randomized studies are required to confirm these results.

Expandable Intravertebral Implants: A Narrative Review on the Concept, Biomechanics, and Outcomes in Traumatology

Expandable intravertebral implants are self-expanding devices applied percutaneously by the posterior transpedicular approach. These devices introduce the concept of anatomical restoration of vertebral body endplates and direct anatomical reduction performed from the interior of the vertebral body with a compression fracture. This paper aims to provide a narrative review on the concept, indications, biomechanical characteristics, as well as functional and radiographic outcomes of the main expandable intravertebral implants currently available, in terms of their application to thoracolumbar spine traumatology. To this end, we performed a search in July 2021 on the MEDLINE/PubMed platform with the words "expandable intravertebral implant", "armed kyphoplasty", "Vertebral Body Stenting" or "stentoplasty" and "SpineJack". The search yielded 144 papers, and of those, we included 15 in this review. We concluded that percutaneous transpedicular posterior access, the ability to reduce vertebral body fractures, particularly of the vertebral endplates and to maintain the vertebral body height, makes the application of expandable intravertebral implants an attractive option in the treatment of thoracolumbar vertebral compression fractures. However, more prospective, randomized, and large-scale blinded studies are still warranted, especially comparative studies between treatments and about the preferential use of an expansive implant over others, in order to gain definitive insights into the effectiveness and indications of each of these devices.

A novel vertebroplasty technique using a larger-diameter needle for thoracolumbar osteoporotic vertebral compression fracture

Percutaneous vertebroplasty (VP) and kyphoplasty (KP) are well-established minimally invasive surgical procedures for the treatment of osteoporotic vertebral compression fractures (OVCF). However, some drawbacks have been reported regarding these procedures, including height loss, cement leakage, and loss of the restored height after balloon deflation. We performed a novel VP technique to minimize these limitations of conventional procedures. This study aimed to compare radiological and clinical outcomes of our method using a larger-diameter needle versus conventional VP (using a smaller needle) for thoracolumbar OVCF.From April 2016 to May 2017, 107 consecutive patients diagnosed with thoracolumbar OVCF were enrolled. Patients were divided into two groups: group 1 underwent conventional VP, i.e., using a smaller diameter needle, and group 2 underwent VP through a modified method with a larger-diameter needle. For radiological evaluation, parameters related to anterior vertebral height (AVH) and segmental angle were assessed using plain standing radiographs, and patient-reported outcomes were evaluated using the visual analog scale. Cement injection amount and leakage pattern were also analyzed. Group 2 showed a larger anterior vertebral height change than group 1 immediately postoperatively and one year postoperatively. The 1-year postoperatively-AVH maintained better in group 2 than in group 1. Group 2 showed more significant improvement of segmental angle immediately postoperatively than group 1 (3.15° in group 1 vs 9.36° in group 2). IYPo-visual analog scale significantly improved in both groups, with greater improvement in group 2 (3.69 in group 1 vs 5.63 in group 2). A substantially larger amount of cement was injected, with a lower leakage rate in group 2 than in group 1.A novel VP technique using a larger-diameter needle showed superior radiological and clinical outcomes than conventional VP. Therefore, it can be considered a useful treatment option for OVCF.

The outcome of expandable titanium mesh implants for the treatment of multi-level vertebral compression fractures caused by multiple myeloma

BACKGROUND

Painful vertebral compression fractures (VCFs) in myeloma patients severely reduce quality of life. Currently, the International Myeloma Working Group (IMWG) and National Institute of Clinical Excellence NICE advocate the use of either balloon kyphoplasty or vertebroplasty in the management of these fractures.

METHODS

All patients with VCFs and myeloma who adhered to the IMWG indications for vertebral augmentation were treated with the Osseofix^® implant. Visual analogue scores (VAS) and Oswestry disability index (ODI) were taken preoperatively and at least one year following surgery. Cobb angle and implant migration were measured on lateral standing radiographs.

RESULTS

Sixteen patients (average age 62, SD = 11.6) consisting of 82 levels (range 3-8) were stabilised with no perioperative complications or revisions at one year. There was an improvement in patient-reported outcomes with the median preoperative VAS of 8.6 (IQR 7.3-10.0) reducing to 3 (IQR 1.0-4.0) after one year (P < 0.001) whilst an average improvement of 31.4 (SD = 19.6) points in the ODI scores was reported (P < 0.001). There was no significant collapse or implant failure at one year with a greater improvement in the VAS/ODI score, when more implants were used (P = 0.049 and 0.008, respectively). The average length of stay was 2.2 days (SD = 1.7).

CONCLUSION

The use of the Osseofix^® implant in VCFs caused by multiple myeloma has shown a statistically significant improvement in both pain and outcome scores. There were no complications or significant radiological deterioration of spinal alignment over the course of a year.

Advances in Vertebral Augmentation Systems for Osteoporotic Vertebral Compression Fractures

Osteoporotic vertebral compression fracture (OVCF) is a common cause of pain and disability and is steadily increasing due to the growth of the elderly population. To date, percutaneous vertebroplasty (PVP) and percutaneous kyphoplasty (PKP) are almost universally accepted as appropriate vertebral augmentation procedures for OVCFs. There are many advantages of vertebral augmentation, such as short surgical time, performance under local anaesthesia, and rapid pain relief. However, there are certain issues regarding the utilization of these vertebral augmentations, such as loss of vertebral height, cement leakage, and adjacent vertebral refracture. Hence, the treatment for OVCF has changed in recent years. Satisfactory clinical results have been obtained worldwide after application of the OsseoFix System, the SpineJack System, radiofrequency kyphoplasty of the vertebral body, and the Kiva VCF treatment system. The following review discusses the development of the current techniques used for vertebral augmentation.

Improved biomechanics of two alternative kyphoplasty cementation methods limit vertebral recollapse

The clinical efficacy of vertebral cement augmentation for compression fractures (VCFs) remains undetermined. Recent studies have shown that refracture and progression of deformity may occur after augmentation with significant clinical consequences. Vertebral body height loss following kyphoplasty has also been observed with cyclic loading. We hypothesized that height loss is partly due to lack of cement fill past the margin of cancellous bone created by balloon expansion with subsequent failure under load. The biomechanical characteristics of two alternative cementation techniques were compared to standard kyphoplasty in cyclically loaded cadaveric VCF constructs. Sectioned osteoporotic thoracolumbar cadaveric spines were compressed to 75% of anterior vertebral height. Specimens were then allocated to standard kyphoplasty, balloon pressurization (BP), with reinflation of the balloon after 50% cement injection, or endplate post (EP), with perforation of the cavity rim using an articulating curette prior to injection. Following cementation, each specimen was preconditioned and loaded over 100,000 cycles. All techniques improved vertebral height (p's < 0.005). The EP and BP techniques provided greater cement fill than the standard technique (p's ≤ 0.01). Normalized vertebral height loss following 100,000 cycles was reduced with the EP technique versus standard kyphoplasty (p < 0.04). Height loss was inversely correlated with cement fill (p < 0.03). No vertebral recollapse occurred with the EP technique in blinded radiographic analysis. Statement of clinical significance: The EP technique demonstrated improved biomechanical characteristics versus the standard technique in cadaveric osteoporotic VCF constructs with decreased recollapse following cementation. This technique may have increased efficacy in cases when kyphoplasty more substantially improves vertebral body height. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:3225-3230, 2018.

Comparative biomechanical study of a new transpedicular vertebral device and vertebroplasty for the treatment or prevention of vertebral compression fractures

BACKGROUND

A comparative study was performed between a novel transpedicular implant (V-STRUT©, Hyprevention, France) and vertebroplasty. This study aims to assess the biomechanical efficacy of this implant in resurrecting and fortifying the osteoporotic vertebra following a vertebral body fracture.

METHODS

A total of 17 vertebrae from 3 human osteoporotic spine segments (T9-L5) were selected. Vertebral compression fractures were generated by eccentric compressive loading until a height reduction of 25%. Then the vertebrae were either fixed using vertebroplasty technique (control group; n = 8) or implanted with V-STRUT© implant combined with bone cement (device group; n = 9). A new compressive loading was performed in the same conditions. Maximal load and stiffness, as well as total energy to fracture were measured.

FINDINGS

Fracture force and energy to fracture were both increased either after V-STRUT© implantation or vertebroplasty compared to when the initial fracture was generated. Mean increase percentage between the initial value and the post-treatment value for each parameter were +77% vs +39% regarding fracture load and +126% vs +99% for energy to fracture, for the device group vs vertebroplasty group respectively. No pedicle fractures were observed in both groups, nor implant breaking or bending in the device group.

INTERPRETATION

These results show the ability of V-STRUT© combined with bone cement to reinforce the vertebral body strength, with an at least equivalent biomechanical performance as vertebroplasty. Further clinical investigation needs to be undertaken to demonstrate any clinical superiority of V-STRUT© over vertebroplasty.

Effect of an Outer Sleeve on an Inflatable Balloon Tamp in Terms of Height Restoration Under Simulated Physiological Load

STUDY DESIGN

An in vitro biomechanical study.

OBJECTIVE

The aim of this study was to determine the effect of an optional sleeve on height restoration and compare it with the fracture reduction achieved by a commercially available inflatable bone tamp under simulated physiological load (110 N).

SUMMARY OF BACKGROUND DATA

Loss of reduction after bone tamp deflation before cement injection still remains a concern. The optional sleeve surrounds the bone tamp to help maintain height during the kyphoplasty procedure while filling the created cavity with bone cement on the contralateral side.

METHODS

Eighteen osteoporotic vertebral bodies (VBs) (T11-L4) were alternately assigned to 1 of the 2 treatment groups: group A: KYPHON (Kyphon Inc.) and group B: AFFIRM with sleeve (Globus Medical Inc.). The VBs were compressed axially at a rate of 5 mm/min until compressed to 40% of the initial anterior height. The fractured VBs then underwent kyphoplasty with cement augmentation while still maintaining load (110 N). The augmented VBs were then recompressed and anterior VB height (mm) and wedge angle (degrees) were measured initially after mechanically creating an anterior wedge fracture, and after repairing the compression fracture. The effect of kyphoplasty on vertebral height, kyphotic angle, cement volumes, and inflation pressures were compared between the treatment groups. Failure load (N) data were compared between intact and repaired VBs.

RESULTS

Average percentage of lost VB height restored in group A was 30%, compared with 56% for group B. The mean changes in wedge angle were similar to those of vertebral height measurements. No significant difference in mean inflation pressures (group A: 175±37 psi; group B: 160±36 psi) were found between the 2 groups. Average percentage increase in failure load was 241% and 212% in groups A and B, respectively.

CONCLUSIONS

Some height restoration was observed using the commercially available bone tamp in fractured VBs under simulated physiological load. The use of an outer sleeve significantly enhanced height restoration compared with the inflatable bone tamp alone.

An In Vitro Evaluation of Fracture Reduction Achieved by Inflatable Bone Tamps Under Simulated Physiological Load

STUDY DESIGN

An in vitro biomechanical study.

OBJECTIVE

To determine the fracture reduction achieved by a novel inflatable bone tamp under simulated physiological load.

SUMMARY OF BACKGROUND DATA

Previous biomechanical studies have showed that kyphoplasty allows near-total restoration of lost vertebral height in unloaded conditions and partial height restoration under simulated physiological loads. Clinically, loss of reduction has been observed after bone tamp deflation, before cement injection. The present study evaluated fracture reduction achieved by an inflatable bone tamp during kyphoplasty while maintaining physiological load. Comparison to commercially available inflatable bone tamp was also performed.

MATERIALS AND METHODS

Eighteen osteoporotic vertebral bodies (T11-L4) were alternately assigned to one of the 2 treatment groups: group A-AFFIRM (Algea Thearpies, a division of Globus Medical Inc., Audubon, PA); and group B-KYPHON (Kyphon Inc., Sunnyvale, CA). The vertebral bodies were compressed axially on an MTS Bionix 858 machine at a rate of 5 mm/min until compressed to 40% of the initial anterior height. Load versus displacement was recorded. The fractured VBs then underwent kyphoplasty with cement augmentation. The augmented vertebral bodies were then recompressed and anterior vertebral body height (mm) and wedge angle (degrees) was measured initially, after mechanically creating an anterior wedge fracture, and after repairing the compression fracture. Each vertebral body was subjected to 111 N load to simulate in vivo physiological loading during inflation and cement augmentation. The vertebral height, wedge angle, cement volume, and inflation pressures were compared between the treatment groups using an unpaired t test (P<0.05). Failure loads were compared between intact and repaired VBs using a paired t test (P<0.05).

RESULTS

Average lost height restored in group A was 29%, and 30% in group B compared to the compressed state. Similar trends were observed in the mean changes of vertebral body wedge angle in both the groups. No significant difference in mean inflation pressures (group A 182±33 psi; group B 175±37 psi) were found between the 2 groups. Average percentage increase in failure load was 218% and 241% for groups A and B, respectively. Mean injected cement volume was 6.65±0.65 and 6.73±0.41 mL for groups A and B, respectively.

CONCLUSIONS

Some height restoration was observed using the 2 bone tamps in fractured vertebral bodies under simulated physiological load. The fracture reduction achieved by the 2 inflatable bone tamps was equivalent. No significant difference between mean inflation pressures and failure load was demonstrated between the 2 groups.

Evaluation of surgical outcome of Jack vertebral dilator kyphoplasty for osteoporotic vertebral compression fracture-clinical experience of 218 cases

Background

Osteoporotic vertebral compression fracture is a serious complication of osteoporosis. Various vertebral kyphoplasty surgeries, which have their own unique features, are commonly used for osteoporotic vertebral compression fracture. Based on the anatomic property of the thoracolumbar vertebral pedicle that its horizontal diameter is twice that of the vertical diameter, we designed Jack vertebral dilator for better restoration of the vertebral height by manipulating the mechanical force.

Methods

A total of 218 patients (236 vertebrae) with osteoporotic vertebral compression fracture were treated with Jack vertebral dilator. Surgery was successfully completed in all cases, and all the 218 patients were followed up for an average of 14.2 months (range 3 to 30 months).

Results

Bone cement leakage occurred in 12 cases, but no symptoms were reported. No other complications were noticed. The VAS scores were 8.2 ± 1.3, 1.7 ± 0.9, and 1.8 ± 0.8 and the ODI was 78.2 ± 13.3 %, 18.5 ± 7.3 %, and 20.9 ± 6.8 % before surgery and 1 week after surgery and at the final follow-up, respectively. The anterior vertebral body height was 19.3 ± 3.2, 25.1 ± 2.6, and 24.9 ± 2.6 mm and the central vertebral body height was 18.7 ± 3.0, 24.8 ± 3.0, and 24.5 ± 2.9 mm before surgery and 1 week after surgery and at the final follow-up, respectively. Cobb angle was 16.2° ± 6.6°, 8.1° ± 5.6°, and 8.5° ± 5.6° before surgery and 1 week after surgery and at the final follow-up, respectively.

Conclusions

Jack vertebral dilator kyphoplasty for osteoporotic vertebral compression fracture is safe, feasible, and effective and has the prospect of further broad application in the future.

Electronic supplementary material

The online version of this article (doi:10.1186/s13018-016-0371-4) contains supplementary material, which is available to authorized users.

Cementless Titanium Mesh Fixation of Osteoporotic Burst Fractures of the Lumbar Spine Leads to Bony Healing: Results of an Experimental Sheep Model

Introduction. Current treatment strategies for osteoporotic vertebral compression fractures (VCFs) focus on cement-associated solutions. Complications associated with cement application are leakage, embolism, adjacent fractures, and compromise in bony healing. This study comprises a validated VCF model in osteoporotic sheep in order to (1) evaluate a new cementless fracture fixation technique using titanium mesh implants (TMIs) and (2) demonstrate the healing capabilities in osteoporotic VCFs. Methods. Twelve 5-year-old Merino sheep received ovariectomy, corticosteroid injections, and a calcium/phosphorus/vitamin D-deficient diet for osteoporosis induction. Standardized VCFs (type AO A3.1) were created, reduced, and fixed using intravertebral TMIs. Randomly additional autologous spongiosa grafting (G1) or no augmentation was performed (G2, n = 6 each). Two months postoperatively, macroscopic, micro-CT and biomechanical evaluation assessed bony consolidation. Results. Fracture reduction succeeded in all cases without intraoperative complications. Bony consolidation was proven for all cases with increased amounts of callus development for G2 (58.3%). Micro-CT revealed cage integration. Neither group showed improved results with biomechanical testing. Conclusions. Fracture reduction/fixation using TMIs without cement in osteoporotic sheep lumbar VCF resulted in bony fracture healing. Intravertebral application of autologous spongiosa showed no beneficial effects. The technique is now available for clinical use; thus, it offers an opportunity to abandon cement-associated complications.

Fracture care using percutaneously applied titanium mesh cages (OsseoFix®) for unstable osteoporotic thoracolumbar burst fractures is able to reduce cement-associated complications--results after 12 months

Background

Despite the known demographic shift with expected doubled rate of vertebral body fractures by the year 2050, a standardized treatment concept for traumatic and osteoporotic incomplete burst fracture of the truncal spine does not exist. This study aims to determine whether minimally invasive fracture care for incomplete osteoporotic thoracolumbar burst fractures using intravertebral expandable titanium mesh cages is a suitable procedure and may provide improved safety in terms of cement-associated complications in comparison to kyphoplasty procedure.

Methods

In 2011/2012, 15 patients (10 women, 5 men; mean age 77) with 15 incomplete osteoporotic thoracolumbar burst fractures (T10 to L4) were stabilized using intravertebral expandable titanium mesh cages (OsseoFix®) as part of a prospective study. X-ray, MRI and bone density measurements (DXA) were performed preinterventionally. The clinical and radiological results were evaluated preoperatively, postoperatively and after 12 months according to the visual analogue scale (VAS), the Oswestry Disability Index (ODI), X-ray (Beck Index, Cobb angle) and CT analyses. Wilcoxon rank sum test, sign test and Fischer’s exact test were used for statistical evaluation.

Results

A significant reduction in pain intensity (VAS) from preoperative 8.0 to 1.6 after 12 months and significant improvement in activity level (ODI) from preoperative 79.0 to 30.5 % after 12 months were revealed. Radiologically, the mean kyphotic angle according to Cobb showed significant improvements from preoperative 9.1° to 8.0° after 12 months. A vertebral body subsidence was revealed in only one case (6.7 %). No changes in the position of the posterior wall were revealed. No cement leakage or perioperative complications were seen.

Conclusion

As a safe and effective procedure, the use of intravertebral expandable titanium mesh cages presents a valuable alternative to usual intravertebral stabilization procedures for incomplete osteoporotic burst fractures and bears the potential to reduce cement-associated complications.

Trial registration

German Clinical Trials Register (DKRS) DRKS00008833.

Intrabody application of eptotermin alpha enhances bone formation in osteoporotic fractures of the lumbar spine; however, fails to increase biomechanical stability - results of an experimental sheep model

This study analyses the effect of eptotermin α application into fractured vertebrae. It is hypothesized that eptotermin α is capable to enhance bony healing of the osteoporotic spine. In 10 Merino sheep osteoporosis induction was performed by ovariectomy, corticosteroid therapy and calcium/phosphorus/vitamin D-deficient diet; followed by standardized creation of lumbar vertebral compression fractures (VCFs) type A3.1 and consecutive fracture reduction/fixation using expandable mesh cages. Randomly, intravertebral eptotermin α (G1) or no augmentation was added (G2). Macroscopic, micro-CT, and biomechanical evaluation assessed bony consolidation two months postoperatively: Micro-CT data revealed bony consolidation for all cases with significant increased callus development for G2 (60%) and BV/TV (bone volume/total volume 73.45%, osteoporotic vertebrae 35.76%). Neither group showed improved biomechanical stability. Eptotermin α enhanced mineralisation in VCFs in an experimental setup with use of cementless augmentation via an expandable cage. However, higher bone mineral density did not lead to superior biomechanical properties.

Efficacy and safety of vertebral stenting for painful vertebral compression fractures in patients with metastatic disease

BACKGROUND AND PURPOSE

Painful vertebral compression fractures in cancer patients reduce quality of life and may limit survival. We assessed pain relief, vertebral height restoration, and kyphosis correction following vertebral augmentation using a novel expandable titanium stent implant in cancer patients with painful vertebral compression fractures.

MATERIALS AND METHODS

Patients >18 years of age with metastatic disease who presented symptomatic compression fractures of vertebral bodies T5-L5, with or without a history of osteoporosis, were included in the study. Back pain at presentation, immediately after vertebral stenting, and at 1-, 3-, 6-, and 12-month follow-up was estimated using the visual analog scale (VAS). Vertebral height and local kyphotic angle (alpha angle) were measured on lateral standing X-ray before and 1-3 months after stenting.

RESULTS

Forty-one cancer patients with painful vertebral compression fractures underwent vertebral stenting procedures at 55 levels. There was no perioperative mortality and no significant complication. Median preoperative VAS was 8.0 (range 8-10), falling to 2.0 immediately postop (range 1-6, P  =  0.000) and 0 at all subsequent follow-up (P ≤ 0.012). Mean preoperative vertical height loss was 25.8% (range 0-84.0%) versus a postoperative mean of 18.0% (range 0-66.0%, P  =  0.000). Median pre- and postoperative kyphotic angle improved from 8.3° (range 0.2°-54.0°) to 7.1° (range 0.2°-25.0°, P  =  0.000). Wilcoxon signed rank test or student's t-test was used for comparisons.

CONCLUSIONS

Vertebral augmentation using a novel vertebral stenting system provided immediate and enduring pain relief and improved vertebral height loss and kyphotic angle.

Cementless fixation of osteoporotic VCFs using titanium mesh implants (OsseoFix): preliminary results

INTRODUCTION

Vertebral compression fractures (VCFs) affect 20% of people over the age of 70 with increasing incidence. Kypho-/vertebroplasty as standard operative procedures are associated with limitations like cement leakage, limited reduction capabilities, and risk for adjacent fractures. To address these shortcomings, we introduce a new minimal invasive cementless VCF fixation technique.

METHODS

Four patients (72.3 years, range 70-76) with VCFs type AO/Müller A1.3 and concomitant osteoporosis were treated by minimal invasive transpedicular placement of two intervertebral mesh cages for fracture reduction and maintenance. Follow-up included functional/radiological assessment and clinical scores and averaged 27.7 months (24-28).

RESULTS

Endplate reduction was achieved in all cases (mean surgery time: 28.5 minutes). Kyphotic (KA) and Cobb angle revealed considerable improvements postoperatively (KA 14.5° to 10.7°/Cobb 10.1° to 8.3°). Slight loss of vertebral reduction (KA: 12.6°) and segment rekyphosis (Cobb: 10.7°) were observed for final follow-up. Pain improved from 8.8 to 2.8 (visual analogue scale). All cases showed signs of bony healing. No perioperative complications and no adjacent fractures occurred.

CONCLUSION

Preliminary results in a small, selected patient collective indicate the ability of bony healing for osteoporotic VCFs. Cementless fixation using intravertebral titanium mesh cages revealed substantial pain relief, adequate reduction, and reduction maintenance without complications. Trial registration number is DRKS00005657, German Clinical Trials Register (DKRS).

Percutaneous Stabilization System Osseofix® for Treatment of Osteoporotic Vertebral Compression Fractures - Clinical and Radiological Results after 12 Months

Study Design

A prospective consecutive cohort study (follow-up study).

Objective

Our study investigated whether implantation of an expandable titanium mesh cage (Osseofix®) is a successful and safe minimally invasive therapy for osteoporotic vertebral compression fractures (VCF). Our experiences, clinical and radiological findings after 12 months follow-up are presented. Kypho- and vertebroplasty are well-established minimally invasive procedures for the treatment of osteoporotic VCF. The main complications associated with both procedures are uncontrolled bone cement leakage. Therefore a suitable alternative has been investigated.

Methods

During June 2010 to May 2011 24 patients were included with 32 osteoporotic VCF (T6 to L4). All of them were stabilized with the Osseofix® system. Preinterventionally we performed X-ray, MRI, and bone density measurements (DXA). Clinical and radiological results were evaluated preop., postop. and after 12 months postop. based on the Oswestry Disability Index (ODI) and the Visual Analogue Scale (VAS), X-ray (Beck Index, Cobb-angle) and CT.

Results

There was a significant improvement in the mean ODI (70,6% to 30,1%) as well as a significant reduction in pain intensity (VAS) (7,7 to 1,4) after 12 month. The mean kyphotic angle according to Cobb showed significant improvements (11,7° to 10,4°) after 12 months. Postinterventional imaging showed only one case of loss of height in a stabilized vertebral body (3.1%). We saw no changes in posterior vertebral wall or adjacent fractures. Except for one pronounced postoperative hematoma we saw no surgical complications including no cement leakage.

Conclusions

Stabilization of symptomatic osteoporotic VCF with Osseofix® system is a safe and effective procedure, even in fractures with posterior wall involvement. The clinical mid-term results are good at a very low complication rate. The Osseofix® system is an interesting alternative to the established procedures of cement augmentation.

Vertebral augmentation with nitinol endoprosthesis: clinical experience in 40 patients with 1-year follow-up

PURPOSE

This study was designed to assess the clinical outcomes of patients treated by vertebral augmentation with nitinol endoprosthesis (VNE) to treat painful vertebral compression fractures.

METHODS

Forty patients with one or more painful osteoporotic VCF, confirmed by MRI and accompanied by back-pain unresponsive to a minimum 2 months of conservative medical treatment, underwent VNE at 42 levels. Preoperative and postoperative pain measured with Visual Analog Scale (VAS), disability measured by Oswestry Disability Index (ODI), and vertebral height restoration (measured with 2-dimensional reconstruction CT) were compared at last follow-up (average follow-up 15 months). Cement extravasation, subsequent fractures, and implant migration were recorded.

RESULTS

Long-term follow-up was obtained in 38 of 40 patients. Both VAS and ODI significantly improved from a median of 8.0 (range 5-10) and 66 % (range 44-88 %) to 0.5 (range 0-8) and 6 % (range 6-66 %), respectively, at 1 year (p < 0.0001). Vertebral height measurements comparing time points increased in a statistically significant manner (ANOVA, p < 0.001). Overall cement extravasation rate was 9.5 %. Discal and venous leakage rates were 7.1 and 0 % respectively. No symptomatic extravasations occurred. Five of 38 (13.1 %) patients experienced new spontaneous, osteoporotic fractures. No device change or migration was observed.

CONCLUSIONS

VNE is a safe and effective procedure that is able to provide long-lasting pain relief and durable vertebral height gain with a low rate of new fractures and cement leakages.

CT fluoroscopy-guided vertebral augmentation with a radiofrequency-induced, high-viscosity bone cement (StabiliT(®)): technical results and polymethylmethacrylate leakages in 25 patients

OBJECTIVE

To assess the technical results of CT fluoroscopy-guided, radiofrequency-induced vertebral augmentation (StabiliT®) in terms of vertebral height restoration and polymethylmethacrylate (PMMA) leakages, occurring in 25 individual patients with vertebral compression fractures and osteolysis.

MATERIALS AND METHODS

From 07/2010 to 08/2011, 25 patients (16 women, nine men; age 71 ± 14; range 41-89) with painful vertebral compression fractures due to osteoporosis (n = 19), metastases (n = 2) or multiple myeloma (n = 4) underwent vertebral augmentation with a radiofrequency-activated, high-viscosity polymethylmethacrylate (PMMA) bone cement (StabiliT® Vertebral Augmentation system; DFINE Europe GmbH, Mannheim) under local anesthesia. Thirty-four vertebrae (Th5-L5) were treated in 27 sessions under CT fluoroscopy guidance (128-row CT, Somatom Definition AS, Siemens, Erlangen) using a unilateral access and a cavity-creating osteotome prior to remote-controlled, hydraulically driven cement injection. 1/2/3 levels were treated in 21/5/1 session(s). Vertebral height change in the midsagittal plane (anterior, midvertebral, posterior endplate distance) and PMMA leaks were retrospectively evaluated using the postinterventional CT.

RESULTS

All patients were successfully treated in the first session. Mean (MV ± SD) procedure time and amount of injected PMMA were 56 ± 14 min and 4.5 ± 1.4 ml, respectively. Mean anterior/midvertebral/posterior height gain was +7.1/+9.7/+0.4%. Small local vertebral leaks were observed in 18/34 vertebrae (53%) without any clinical sequelae. No major complications occurred.

CONCLUSIONS

CT fluoroscopy-guided, RF-induced vertebral augmentation with a high-viscosity bone cement (StabiliT®) was safe and technically successful in all patients. Using a hydraulic cement injection technique, a moderate restoration of anterior and midvertebral height was seen while the system was not markedly superior to standard vertebroplasty regarding the frequency of minor asymptomatic PMMA leaks.

An ex vivo biomechanical comparison of a novel vertebral compression fracture treatment system to kyphoplasty

BACKGROUND

Vertebral compression fracture repair aims to relieve pain and improve function by restoring vertebral structure and biomechanics, but is still associated with risks arising from polymethylmethacrylate cement extravasation. The Kiva® Vertebral Compression Fracture Treatment System, a stacked coil implant made of polyetheretherketone and delivered over a guide-wire, is a novel device designed to provide height restoration and mechanical stabilization, while improving cement containment and minimizing disruption of cancellous bone. The objective of this study was to determine whether the Kiva system is as effective as balloon kyphoplasty at restoring mechanical properties in osteoporotic vertebral compression fractures.

METHODS

Wedge fractures were created in the middle vertebra of fourteen osteoporotic three-vertebra spine segments and then repaired with either the Kiva or kyphoplasty procedure. Height, stiffness and displacement under compression of the spine segments were measured for four conditions: intact, fractured, augmented, and post-cyclic eccentric loading (50,000cycles, 200-500N, 30mm anterior lever arm).

FINDINGS

No significant differences were seen between the two procedures for height restoration, stiffness at high or low loads, or displacement under compression. However, the Kiva System required an average of 66% less cement than kyphoplasty to achieve these outcomes (mean 2.6 (SD 0.4) mL v. mean 7.5 (SD 0.8) mL 0; P<0.01). Extravasations and excessive posterior cement flow were also significantly lower with Kiva (0/7 v. 4/7; P<.05).

INTERPRETATION

Kiva exhibits similar biomechanical performance to balloon kyphoplasty, but may reduce the risk of extravasation through the containment mechanism of the implant design and by reducing cement volume.

Vertebral body reconstruction system B-Twin® versus corset following non-osteoporotic Magerl A1.2 thoracic and lumbar fracture. Functional and radiological outcome at 12 month follow-up in a prospective randomized series of 50 patients

INTRODUCTION

Kyphoplasty and percutaneous vertebroplasty are two effective procedures for osteoporotic vertebral compression fractures, but there have been few publications on their use in non-osteoporotic forms. B-Twin(®) vertebral body reconstruction is a new minimally invasive vertebral body reconstruction technique developed for non-osteoporotic vertebral compression fractures of the thoracolumbar junction and lumbar spine.

OBJECTIVES

The present study describes this novel technique and assessed efficacy compared to a conservative method.

PATIENTS AND METHODS

Inclusion criteria were: Magerl type A1.2 non-osteoporotic thoracolumbar or lumbar spinal compression fractures in patients aged over 18 years, free of neurologic compromise. Patients were randomized to management by corset (group 1) or by the B-Twin(®) spacer (group 2). Follow-up used a visual analog scale (VAS) to assess pain, the Oswestry Disability Index (ODI) and, on radiology, the vertebral (VK) and regional (RK) kyphosis angles and anterior and medial height indices at baseline, 3 months and 12 months.

RESULTS

Group 1 comprised 26 patients; group 2 comprised 24 patients, with 44 implants. In group 1, mean VK was 10.7° (± 1.73°) at baseline, 11.9° (± 1.56°) at 3 months and 12.3° (± 1.6°) at 12 months. Mean RK was respectively 9.7° (± 0.97°), 11.10° (± 1.07°) and 11.8° (± 1.27). Mean medial height (medial-to-posterior [MH/PH] height ratio was respectively 0.75 [±0.05], 0.70 [±0.06] and 0.65 [±0.04]). Mean anterior height (anterior-to-posterior [AH/PH] height ratio) was respectively 0.79 [± 0.06], 0.76 [± 0.05] and 0.73 [± 0.05]). Mean VAS score was respectively 8.6 (± 0.52), 3.8 (± 0.82) and 2.3 (± 0.83). In group 2, mean VK was 13.8° (± 0.47°) at baseline, 4.88° (± 0.65°) at 3 months and 4.88° (± 0.65°). Mean RK was respectively 9.82° (± 1.67°), 4.47° (± 0.86°) and 4.82° (± 0.98°). Mean MH/PH ratio was respectively 0.69 (± 0.05), 0.86 (± 0.03) and 0.86 (± 0.03). Mean AH/PH ratio was respectively 0.73 (± 0.04), 0.90 (± 0.03) and 0.90 (± 0.03). Mean VAS score was 8.88 (± 0.47) at baseline, 2 (± 1) at 1-day post-surgery, 1.71 (± 0.88) at 3 months and 1.12 (± 0.23) at 12 months. The increase in vertebral body height in patients managed by B-Twin(®) was maintained at 6 and 12 months (P<0.0001). The study showed better results with the vertebral spacer than on conservative treatment, with a 95% reduction in bed-rest: 4-6 weeks in the conservative group vs. 2-3 days in the surgical group.

CONCLUSIONS

The vertebral body reconstruction technique provided anatomic vertebral body reconstruction and quick return to household activity without resort to a corset. Deformity was durably reduced. At 12-month follow-up, pain reduction and stasis were achieved. The risk of injected cement leakage was slight.