[Balloon kyphoplasty]. / Ballonkyphoplastie.

Kyphoplasty is a reliable, minimally invasive method to stabilize fractured vertebral bodies. Under economic aspects kyphoplasty seems advantageous compared with conservative treatment in patients with osteoporotic fractures as well as in younger persons after traumatic spine fractures. Both groups show a better outcome after kyphoplasty regarding pain, function and recovery of height of the treated vertebral body. Specifically young trauma patients benefit from this technique with short hospitalization and early return to work.

[Filling of metaphyseal defects with nanocrystalline hydroxyapatite (Ostim) for fractures of the radius]. / Verwendung von nanokristallinem Hydroxyapatit (Ostim) bei der Versorgung von Radiusfrakturen.

AIM OF THE STUDY: In this study, innovative bone replacement material was tested after complicated metaphyseal radius fractures with the affected joints. MATERIAL AND METHODS: In all, 11 C 2, 11 C 3 and 3 A 3 radius fractures were treated by surgery combining an angularly stable palmar plate osteosynthesis with defect filling using nanocrystalline hydroxyapatite. Examinations were conducted preoperatively and postoperatively after 4 weeks, 12 weeks and 9-12 months. RESULTS: After 10.5+/-1.4 months, inclination angles of 8.7+/-1.8 degrees (dorsopalmar) and 18.8+/-2.9 degrees (radioulnar) were measured at the treated fractures, the ulnar drift was 0.6+/-1.8 mm. According to the Gartland/Werley scale, 10 therapeutic results were considered "excellent", 12 "good" and 3 "fair". CONCLUSION: An angularly stable plate osteosynthesis with metaphyseal defect filling using nanocrystalline hydroxyapatite for the treatment of A 3, C 2 and C 3 radius fractures showed satisfactory radiological and clinical results.

[In vitro studies on various PMMA bone cements: a first comparison of new materials for arthroplasty]. / In-vitro-Untersuchung unterschiedlicher PMMA-Knochenzemente--ein erster Vergleich neuer Materialien für die Endoprothetik.

AIM: Two clinically established PMMA bone cements (Refobacin Palacos R and Palacos R + G) and two newer cements not yet in widespread clinical use (Refobacin Bone Cement R and SmartSet GHV) were tested in vitro for practically relevant differences. METHODS: The tests included chemical analyses, handling properties and testing according to the ISO standard for PMMA bone cements. RESULTS: The results obtained indicate clearly that the copolymers used in Refobacin Bone Cement R and SmartSet GHV differ from those used in the Palacos cements. There were also significant differences in viscosity behaviour and waiting time (p < 0.01 for Palacos cements versus Refobacin Bone Cement R) as an expression of different handling properties. The hardening times under ISO 5833 conditions also differed significantly (p < 0.01 and p < 0.05 for Palacos cements compared with Refobacin Bone Cement R and p < 0.01 for Refobacin Bone Cement R compared with SmartSet GHV). CONCLUSION: In view of these differences in material properties, the clinical data from long-term use of the bone cements Refobacin Palacos R and Palacos R + G cannot be extrapolated to the newly developed PMMA cements Refobacin Bone Cement R and Smart GHV. Before broad clinical use of these cements, prospective clinical studies using RSA or DEXA and, as a second step, statistically powerful prospective comparative studies should be performed. Until these data are available, patients in whom Refobacin Bone Cement R and SmartSet GHV are used should be informed that the material employed deviates from the standard procedures for cemented joint replacement in the Scandinavian arthroplasty registers and that the long-term consequences cannot, in the final instance, be foreseen. This is essential in order to avoid later malpractice claims on the grounds of inadequate information.

[Balloon kyphoplasty in the treatment of back pain]. / Die Ballonkyphoplastie in der Behandlung des Rückenschmerzes.

BACKGROUND: Experience of just under 5 years has shown that balloon kyphoplasty can be just as successfully employed as the longer-stablished vertebroplasty for the treatment of back pain due to recent or prior osteoporotic fractures as well as new traumatic fractures. MATERIAL AND METHOD: Among 345 patients with a total of 690 treated vertebral bodies, the change in pain symptomatology was analyzed for a follow-up period of 12 months in 40 study patients who underwent kyphoplasty and a control group of 20 patients. In addition, the pain experienced by a further 29 patients with new traumatic vertebral body fractures was monitored over a 12-month period. These fractures were partly managed by fixateur interne alone and by a combination of fixateur interne and kyphoplasty. RESULTS: The 40 patients treated by kyphoplasty had a baseline VAS score of 26.2+/-2.00, which increased to 44.4+/-3.11 after 12 months, while the respective scores for the control group were 33.6+/-4.21 and 34.3+/-4.35. In the 29 patients with new traumatic vertebral body fractures, the initial VAS score was 62 and after 12 months a distinct reduction of pain was noted with a score of 20 (100 = maximum pain, 0 = no pain). The number of times that the 40 patients managed by kyphoplasty had to consult their general practitioner was significantly reduced by the pain therapy. CONCLUSION: Balloon kyphoplasty verifiably improved the pain symptomatology after vertebral fracture over a period of 12 months. Comparison with the control group, which received the same osteoporosis drug therapy, confirmed the effect of this minimally invasive treatment form.

Osseous integration of calcium phosphate in osteoporotic vertebral fractures after kyphoplasty: initial results from a clinical and experimental pilot study.

INTRODUCTION: This study evaluated the radiological changes at the bone-cement interface of calcium phosphate cement (CPC) and polymethylmethacrylate (PMMA) 12 months after kyphoplasty. In a pilot experiment, we additionally performed a histomorphometric analysis in osteopenic foxhounds to analyze the process of osseous integration of CPC and PMMA. METHODS: Twenty postmenopausal female patients with 46 vertebral compression fractures (VCF) were treated by kyphoplasty, utilizing CPC (N=28) or PMMA (N=18) for intravertebral stabilization. After a 12-month follow-up, we measured the density changes of border voxels at the bone-cement interface by computed tomography (CT) using dedicated software algorithms. We defined the border-voxel density (BVD) as a parameter of cement resorption at the interface. We also investigated the bone-implant interface in three osteopenic foxhounds by histomorphometry 3, 6, and 12 months after cement implantation. RESULTS: Twelve months after kyphoplasty, only CPC showed a significant decrease of the BVD compared to PMMA (p<0.01), indicating a slow progress of resorption at the interface. Histomorphometry of the dog vertebrae showed near total bone coverage of CPC implants, whereas the PMMA surface exhibited only 30% direct bone contact (p<0.01). We also observed a time-dependent increase in the number of discernable osteons close to the interface of CPC, but no bone tissue within PMMA (p<0.01). CONCLUSIONS: The decrease of the BVD 12 months after kyphoplasty may indicate osseous integration of CPC by: (1) the ingrowth of bone tissue and (2) osteonal penetration close to the interface.

Open reduction and palmar plate-osteosynthesis in combination with a nanocrystalline hydroxyapatite spacer in the treatment of comminuted fractures of the distal radius.

In a prospective study, we used the nanocrystalline hydroxyapatite paste Ostim (Osartis, Obernburg, Germany) in combination with a palmar plate to treat comminuted radius fractures with a metaphyseal and articular component in order to examine the clinical use of Ostim as a bone substitute. Twenty-one patients with 22 radius fractures of AO types C2 and C3 were included in the study. The measurements, taken 10.2+/-1.3 months after the initial treatment, revealed a dorsopalmar tilt of 8.8+/-3.7 degrees , a radioulnar inclination of 18.8+/-2.8 degrees and an ulnar variance of 0.8+/-1.8mm. According to the Gartland and Werley evaluation, eight of the treated fractures attained an excellent, 11 a good and the remaining three a fair result. The study demonstrates that Ostim, in combination with angularly stable osteosynthesis, can be used as an acceptable bone substitute for the treatment of type C2 and C3 radial fractures.

CT volumetry of intravertebral cement after kyphoplasty. Comparison of polymethylmethacrylate and calcium phosphate in a 12-month follow-up.

This study was intended to measure the volume of intravertebral cement after balloon kyphoplasty with high resolution computed tomography (CT) and dedicated software. Volume changes of biocompatible calcium phosphate cement (CPC) were detected during a follow-up of 12 months. Measurements were compared with a control group of patients treated with polymethylmethacrylate (PMMA). Twenty-three vertebrae (14 CPC, 9 PMMA) of 12 patients were examined with CT using an identical imaging protocol. Dedicated software was used to quantify intravertebral cement volume in subvoxel resolution by analyzing each cement implant with a density-weighted algorithm. The mean volume reduction of CPC was 0.08 ml after 12 months, which corresponds to an absorption rate of 2 vol%. However, the difference did not reach significance level (P>0.05). The mean error estimate was 0.005 ml, indicating excellent precision of the method. CT volumetry appears a precise tool for measurement of intravertebral cement volume. CT volumetry offers the possibility of in vivo measurement of CPC resorption.

[The evaluation of balloonkyphoplasty for osteoporotic vertebral fractures. An interdisciplinary concept]. / Die Wertigkeit der Ballonkyphoplastie bei der osteoporotischen Wirbelkörperfraktur. Ein interdisziplinäres Konzept.

BACKGROUND DATA: Patients with osteoporotic vertebral compression fractures frequently complain of pain and a loss of function and mobility. Such fractures are associated with an increased mortality. The common treatment with bed rest, bracing or osteosynthesis does not lead to satisfying results. With two new surgical techniques, vertebroplasty and kyphoplasty, an internal stabilisation of osteoporotic vertebral fractures is possible. METHODS: All patients were treated by kyphoplasty. With a minimal invasive dorsal approach, an inflatable bone tamp is placed in the fractured vertebral body. This tamp can restore the vertebral body height and create a cavity, which is filled with bone cement under low pressure. The advantage of kyphoplasty compared to vertebroplasty is the restoration of the vertebral height and a decreased cement leakage rate. We performed a prospective, interdisciplinary study with a follow-up of 12 months. We treated 192 vertebral fractures in 102 patients. Augmentation was performed with polymethylmethacrylate in 138 cases and with a new injectable calcium phosphate-cement in 54 vertebral bodies. Outcome data were obtained with two different spine-scores and by the radiomorphometric evaluation of x-rays before and after treatment. RESULTS: We noticed a significant improvement in pain and function in 89% of the patients. All patients showed a regain of vertebral height of on average 17%. In 7% of all treated vertebral bodies, we noticed cement leakage, which was, however, far below the rates published for vertebroplasty (20-70%). There were two complications, bleeding due to an unknown coagulopathy and a violation of the myelon by malpunction. CONCLUSION: Kyphoplasty is a reliable and minimally invasive method for stabilizing fractured osteoporotic vertebral bodies. Improvement of pain and function and a regain in height of the treated vertebral body can be accomplished.

[Balloon kyphoplasty of vertebral compression fractures with a new calcium phosphate cement]. / Augmentation von Wirbelkörperfrakturen mit einem neuen Calciumphosphat-Zement nach Ballon-Kyphoplastie.

QUESTION: Can the same levels of pain reduction and increase in function be achieved in kyphoplasty procedures with Calcibon as with polymethylmethacrylate (PMMA) cement? PATIENTS AND METHODS: In a prospective, interdisciplinary single-center study, 99 patients (173 vertebral fractures) were treated with kyphoplasty. Augmentation was performed with PMMA in 66 cases (127 vertebral bodies) and with Calcibon in 33 patients (46 vertebral bodies). Outcome data were obtained with a VAS spine score and by radiomorphometric evaluation of X-rays before and after treatment. RESULTS: Pain and function improved in 87% of the patients; an average of 16% of the lost vertebral height was regained. A 9% cement leakage rate was observed with PMMA and 10% with Calcibon. There was no significant difference in pain reduction and radiomorphometric evaluation between the two techniques. CONCLUSION: Kyphoplasty is a reliable, minimally invasive method to stabilize fractured vertebral bodies. Augmentation with Calcibon improves pain and function and enables the treated vertebral body to regain of height.

[Kyphoplasty and vertebroplasty in fractures in the elderly: effort and effect]. / Kyphoplastie und Vertebroplastie bei Frakturen im hohen Lebensalter. Aufwand und Ergebnisse.

Kyphoplasty and vertebroplasty are two minimally invasive percutaneous techniques used for treatment of osteoporotic vertebral compression fractures in the thoracic and lumbar spine. The injection of polymethylmetacrylate (PMMA) is often a final attempt at therapeutic treatment of complications due to such fractures. Vertebroplasty involves injection of cement via one or both pedicles under high pressure, thus filling and stabilizing the vertebra without reduction of fracture. Extravertebral cement leakage is a common complication: an intact posterior wall normally prevents cement leakage into the epidural space. Kyphoplasty involves transpedicular inflation of balloon tamps, thus creating a cavity which is then filled with PMMA under low pressure. Restoration of vertebral height is possible and the potential for extravertebral cement leakage lessened.