Florian Geiger

The effect of platelet-rich plasma on healing in critical-size long-bone defects

The role of platelet-rich plasma (PRP) as a promoter of bone healing remains controversial. The hypothesis investigated was that PRP improves bone healing of a critical-size diaphyseal radius defect in a rabbit model. The bone defect was filled with a high-surface ceramic scaffold, calcium-deficient hydroxyapatite (CDHA), with the addition of allogenic PRP, mesenchymal stem cells (MSC) or both. PRP yielded better bone formation than the empty CDHA scaffold as determined by both histology and micro-computer tomography (p<0.05) after 16 weeks, whereas no difference was observed on biomechanical testing. Similar behavior was found in samples with MSC; however, the combination of MSC and PRP did not further improve bone healing. Furthermore, the resorption of CDHA was improved by the addition of PRP, MSC and MSC/PRP, but there were no differences between the groups. The areas of bone formation were greater in areas adjacent to the bone resection areas and towards the intact ulna. In conclusion, PRP improves bone healing in a diaphyseal rabbit model on CDHA and the combination of CDHA. This study supports the allogenic use of PRP for bone healing as an off-the-shelf therapy.

Reduction of radiation dose during facet joint injection using the new image guidance system SabreSource™: a prospective study in 60 patients

Interventional procedures are associated with high radiation doses for both patients and surgeons. To reduce the risk from ionizing radiation, it is essential to minimize radiation dose. This prospective study was performed to evaluate the effectiveness in reducing radiation dose during facet joint injection in the lumbar spine and to evaluate the feasibility and possibilities of the new real time image guidance system SabreSource™. A total of 60 patients, treated with a standardized injection therapy of the facet joints L4–L5 or L5–S1, were included in this study. A total of 30 patients were treated by fluoroscopy guidance alone, the following 30 patients were treated using the new SabreSource™ system. Thus a total of 120 injections to the facet joints were performed. Pain, according to the visual analogue scale (VAS), was documented before and 6xa0h after the intervention. Radiation dose, time of radiation and the number of exposures needed to place the needle were recorded. No significant differences concerning age (mean age 60.5xa0years, range 51–69), body mass index (mean BMI 26.2, range 22.2–29.9) and preoperative pain (VAS 7.9, range 6–10) were found between the two groups. There was no difference in pain reduction between the two groups (60 vs. 61.5%; Pxa0=xa00.001) but the radiation dose was significantly smaller with the new SabreSource™ system (reduction of radiation dose 32.7%, Pxa0=xa00.01; reduction of mean entrance surface dose 32.3%, Pxa0=xa00.01). The SabreSource™ System significantly reduced the radiation dose received during the injection therapy of the lumbar facet joints. With minimal effort for the setup at the beginning of a session, the system is easy to handle and can be helpful for other injection therapies (e.g. nerve root block therapies).

PMMA‐hydroxyapatite composite material retards fatigue failure of augmented bone compared to augmentation with plain PMMA: In vivo study using a sheep model

Polymethylmethacrylate (PMMA) is the most commonly used void filler for augmentation of osteoporotic vertebral fracture, but the differing mechanical features of PMMA and osteoporotic bone result in overload and failure of adjacent bone. The aim of this study was to compare fatigue failure of bone after augmentation with PMMA-nanocrystalline hydroxyapatite (HA) composite material or with plain PMMA in a sheep model. After characterization of the mechanical properties of a composite material consisting of PMMA and defined amounts (10, 20, and 30% volume fraction) of HA, the composite material with 30% volume fraction HA was implanted in one distal femur of sheep; plain PMMA was implanted in the other femur. Native non-augmented bone served as control. Three and 6 months after implantation, the augmented bone samples were exposed to cyclic loading and the evolution of damage was investigated. The fatigue life was highest for the ovine native bone and lowest for bone-PMMA specimens. Bone-composite specimens showed significantly higher fatigue life than the respective bone-PMMA specimens in both 3- and 6-month follow-up groups. These results suggest that modification of mechanical properties of PMMA by addition of HA to approximate those of cancellous bone retards fatigue failure of the surrounding bone compared to augmented bone with plain PMMA.

Anterior vertebroplasty of adjacent levels after vertebral body replacement.

The aim of this study was to evaluate the feasibility of a new method, which should help to avoid cage subsidence after vertebrectomy in short fusions. After implantation of an extendable vertebral body replacement (VBR) the two adjacent endplates to the fractured or destroyed vertebra were augmented with bone cement using the anterior approach in 20 patients with short circumferential fusion. All patients were followed up for 2xa0years clinically and radiographically. X-rays were reviewed for kyphosis, cage subsidence, presence of a solid fusion mass and instrumentation failure. Changes in every day activities (Oswestry Disability Index-ODI) and visual analogue scale (VAS), pain score, as well as technique-related complications were examined. The mean amount of kyphosis correction was 12.8° (±6.4°) and changed by only 0.3° (±0.4°) until last follow-up. Pain (VAS) and ODI scores were significantly improved and did not change until last follow-up. In all but two cases, the authors observed solid union with incorporation of the cage. No surgery-related complications were recorded. In one case revision was advised because of non-union due to septic loosening. The augmentation of the adjacent vertebras after anterior VBR provides an enhancement of the interface between cage and vertebra in cases with poor bone quality and in revision surgery. The technique is simple and safe, as the needles can be placed under visual control. Cement augmentation of the endplates may reduce interbody device subsidence.

Cement distribution in vertebroplasty pedicle screws with different designs

ZusammenfassungDie Auswirkungen der verminderten Knochendichte machen sich im Falle einer Spondylodese besonders bemerkbar. Zur besseren Fixierung der Schrauben im Knochen wurde die Zementaugmentation zum Gegenstand vieler Studien, die die biomechanische Überlegenheit und den erhöhten Auszugswiderstand der zementaugmentierten Schrauben nachgewiesen haben. Aufgrund inadäquater, aber auch gefährlicher Zementverteilungen im Wirbelkörper, bestand die Notwendigkeit zur Entwicklung alternativer Applikationsformen im Vergleich zu der konventionellen Technik. Pedikelschrauben mit seitlichen Öffnungen und einem zentralen Bohrloch wurden eigens für diese Anwendung entwickelt. Diese neuen Schrauben erlauben eine gute Zementaugmentation und vergrößern den Schraubendurchmesser, aber auch die Oberflächenkohäsion zwischen den drei Komponenten (Schraube-Zement-Knochen). Die Zementverteilung kann durch die Auswahl der seitlichen Öffnungen (Größe und Lage) entsprechend beeinflusst werden. Schrauben mit konisch zulaufendem Kerndurchmesser und distal gelegenen weiten Öffnungen führen zur Entstehung einer uniformen Zementwolke.AbstractThe effects of deteriorated bone density become particularly apparent in cases where spinal instrumentation is needed. Cement augmentation of pedicle screws for better bone purchase became the subject of many studies, which proved the biomechanical superiority and the increased pullout strength of cement augmented screws. Inadequate, and sometimes dangerous, cement distribution made the need for development of special implants inevitable. Pedicle screws with side openings and a central drill hole allow cement augmentation through the implant and increase not only the screw diameter but also the interfacial strength between the three components (screw-cement-bone). Accordingly cement distribution can be affected by the selection of the side openings (size and position). Screws with conical core and distally situated side openings facilitate the development of uniform cement dough.The effects of deteriorated bone density become particularly apparent in cases where spinal instrumentation is needed. Cement augmentation of pedicle screws for better bone purchase became the subject of many studies, which proved the biomechanical superiority and the increased pullout strength of cement augmented screws. Inadequate, and sometimes dangerous, cement distribution made the need for development of special implants inevitable. Pedicle screws with side openings and a central drill hole allow cement augmentation through the implant and increase not only the screw diameter but also the interfacial strength between the three components (screw-cement-bone). Accordingly cement distribution can be affected by the selection of the side openings (size and position). Screws with conical core and distally situated side openings facilitate the development of uniform cement dough.

Zementverteilung bei Vertebroplastieschrauben unterschiedlichen Designs

ZusammenfassungDie Auswirkungen der verminderten Knochendichte machen sich im Falle einer Spondylodese besonders bemerkbar. Zur besseren Fixierung der Schrauben im Knochen wurde die Zementaugmentation zum Gegenstand vieler Studien, die die biomechanische Überlegenheit und den erhöhten Auszugswiderstand der zementaugmentierten Schrauben nachgewiesen haben. Aufgrund inadäquater, aber auch gefährlicher Zementverteilungen im Wirbelkörper, bestand die Notwendigkeit zur Entwicklung alternativer Applikationsformen im Vergleich zu der konventionellen Technik. Pedikelschrauben mit seitlichen Öffnungen und einem zentralen Bohrloch wurden eigens für diese Anwendung entwickelt. Diese neuen Schrauben erlauben eine gute Zementaugmentation und vergrößern den Schraubendurchmesser, aber auch die Oberflächenkohäsion zwischen den drei Komponenten (Schraube-Zement-Knochen). Die Zementverteilung kann durch die Auswahl der seitlichen Öffnungen (Größe und Lage) entsprechend beeinflusst werden. Schrauben mit konisch zulaufendem Kerndurchmesser und distal gelegenen weiten Öffnungen führen zur Entstehung einer uniformen Zementwolke.AbstractThe effects of deteriorated bone density become particularly apparent in cases where spinal instrumentation is needed. Cement augmentation of pedicle screws for better bone purchase became the subject of many studies, which proved the biomechanical superiority and the increased pullout strength of cement augmented screws. Inadequate, and sometimes dangerous, cement distribution made the need for development of special implants inevitable. Pedicle screws with side openings and a central drill hole allow cement augmentation through the implant and increase not only the screw diameter but also the interfacial strength between the three components (screw-cement-bone). Accordingly cement distribution can be affected by the selection of the side openings (size and position). Screws with conical core and distally situated side openings facilitate the development of uniform cement dough.The effects of deteriorated bone density become particularly apparent in cases where spinal instrumentation is needed. Cement augmentation of pedicle screws for better bone purchase became the subject of many studies, which proved the biomechanical superiority and the increased pullout strength of cement augmented screws. Inadequate, and sometimes dangerous, cement distribution made the need for development of special implants inevitable. Pedicle screws with side openings and a central drill hole allow cement augmentation through the implant and increase not only the screw diameter but also the interfacial strength between the three components (screw-cement-bone). Accordingly cement distribution can be affected by the selection of the side openings (size and position). Screws with conical core and distally situated side openings facilitate the development of uniform cement dough.

Reduction of radiation dose during radiofrequency denervation of the lumbar facet joints using the new targeting system SabreSource™: a prospective study in 20 patients

Background and aimsFacet joint denervation is a frequently performed technique to treat facet joint syndrome. Most often this technique is used under fluoroscopic guidance implicating high radiation doses for both patients and surgeons. This prospective study was performed to evaluate the effectiveness in reducing radiation dose during radiofrequency ablation therapy of the lumbar facet joints and to evaluate the feasibility and possibilities of the new real time image guidance system SabreSource™.Materials and methodsAs much as 20 consecutive patients with radiofrequency ablation therapy of the facet joints L4 to S1 were included. Ten patients were treated by fluoroscopic control alone; the following 10 patients were treated with the SabreSource™ image guidance system. A total of 40 thermal ablations to the facet joints were performed. Each patient was given one thermal ablation on both sides of the vertebral segment, either to the facet joints of L4–L5 or of L5–S1. Pain, according to the visual analogue scale (VAS), was documented before and 6xa0h after the intervention. Radiation dose, time of radiation and the number of shots needed to place the radiofrequency cannula were recorded.ResultsNo complications occurred. Before therapy, the mean VAS in all patients was 7.6 (range 6–10). After therapy the mean VAS in all patients was 3.4 (range 0–5). Compared to the fluoroscopy-guided thermal ablation therapy the SabreSource™ system significantly reduced the number of fluoroscopy exposures (reduction 23.53%, pxa0=xa00.02), the time of radiation exposure (reduction 21.2%, pxa0=xa00.03) and the mean entrance surface dose (reduction 30.46%, pxa0=xa00.01).ConclusionThe SabreSource System reduces radiation exposure and radiation dose in the radiofrequency denervation therapy of the lumbar facet joints and can be applied for other minimally invasive techniques.

Sinterungsprophylaxe eines Wirbelkörperersatzes

Due to the increasing number of elderly patients with osteoporosis, the incidence of more complex operations demanding a vertebral body replacement is increasing in this population. Cement augmentation of pedicle screws helps to prevent screw pullout. Similarly it is possible to augment the end plates in anterior spine surgery in order to prevent cage subsidence. The technique is simple, quick and safe, as needles can be placed under visual control. In a series of 20 patients neither surgery-related complications nor aseptic loosening were found.ZusammenfassungAufgrund der steigenden Zahl an alten und osteoporotischen Patienten steigt auch die Inzidenz komplexer Wirbelsäulenoperationen, bei denen ein Wirbelkörperersatz in diesem Kollektiv notwendig wird. Durch den Einsatz zementaugmentierter Schrauben konnte die Lockerungsrate bei dorsalen Eingriffen deutlich reduziert werden. Gleichsam ist es bei ventralen Eingriffen möglich die Endplatten so mit Zement zu verstärken, dass Cagesinterungen vermindert werden können. Die Technik ist einfach, schnell und sicher, da die Nadeln unter visueller Kontrolle gesetzt werden können. In einer ersten Serie von 20xa0Patienten konnten weder operationsspezifische Komplikationen noch aseptische Lockerungen festgestellt werden.AbstractDue to the increasing number of elderly patients with osteoporosis, the incidence of more complex operations demanding a vertebral body replacement is increasing in this population. Cement augmentation of pedicle screws helps to prevent screw pullout. Similarly it is possible to augment the end plates in anterior spine surgery in order to prevent cage subsidence. The technique is simple, quick and safe, as needles can be placed under visual control. In a series of 20 patients neither surgery-related complications nor aseptic loosening were found.

[Sintering prophylaxis of a vertebral body replacement: anterior cement augmentation of vertebral end plates].

Due to the increasing number of elderly patients with osteoporosis, the incidence of more complex operations demanding a vertebral body replacement is increasing in this population. Cement augmentation of pedicle screws helps to prevent screw pullout. Similarly it is possible to augment the end plates in anterior spine surgery in order to prevent cage subsidence. The technique is simple, quick and safe, as needles can be placed under visual control. In a series of 20 patients neither surgery-related complications nor aseptic loosening were found.ZusammenfassungAufgrund der steigenden Zahl an alten und osteoporotischen Patienten steigt auch die Inzidenz komplexer Wirbelsäulenoperationen, bei denen ein Wirbelkörperersatz in diesem Kollektiv notwendig wird. Durch den Einsatz zementaugmentierter Schrauben konnte die Lockerungsrate bei dorsalen Eingriffen deutlich reduziert werden. Gleichsam ist es bei ventralen Eingriffen möglich die Endplatten so mit Zement zu verstärken, dass Cagesinterungen vermindert werden können. Die Technik ist einfach, schnell und sicher, da die Nadeln unter visueller Kontrolle gesetzt werden können. In einer ersten Serie von 20xa0Patienten konnten weder operationsspezifische Komplikationen noch aseptische Lockerungen festgestellt werden.AbstractDue to the increasing number of elderly patients with osteoporosis, the incidence of more complex operations demanding a vertebral body replacement is increasing in this population. Cement augmentation of pedicle screws helps to prevent screw pullout. Similarly it is possible to augment the end plates in anterior spine surgery in order to prevent cage subsidence. The technique is simple, quick and safe, as needles can be placed under visual control. In a series of 20 patients neither surgery-related complications nor aseptic loosening were found.

Zementverteilung bei Vertebroplastieschrauben unterschiedlichen Designs@@@Cement distribution in vertebroplasty pedicle screws with different designs

ZusammenfassungDie Auswirkungen der verminderten Knochendichte machen sich im Falle einer Spondylodese besonders bemerkbar. Zur besseren Fixierung der Schrauben im Knochen wurde die Zementaugmentation zum Gegenstand vieler Studien, die die biomechanische Überlegenheit und den erhöhten Auszugswiderstand der zementaugmentierten Schrauben nachgewiesen haben. Aufgrund inadäquater, aber auch gefährlicher Zementverteilungen im Wirbelkörper, bestand die Notwendigkeit zur Entwicklung alternativer Applikationsformen im Vergleich zu der konventionellen Technik. Pedikelschrauben mit seitlichen Öffnungen und einem zentralen Bohrloch wurden eigens für diese Anwendung entwickelt. Diese neuen Schrauben erlauben eine gute Zementaugmentation und vergrößern den Schraubendurchmesser, aber auch die Oberflächenkohäsion zwischen den drei Komponenten (Schraube-Zement-Knochen). Die Zementverteilung kann durch die Auswahl der seitlichen Öffnungen (Größe und Lage) entsprechend beeinflusst werden. Schrauben mit konisch zulaufendem Kerndurchmesser und distal gelegenen weiten Öffnungen führen zur Entstehung einer uniformen Zementwolke.AbstractThe effects of deteriorated bone density become particularly apparent in cases where spinal instrumentation is needed. Cement augmentation of pedicle screws for better bone purchase became the subject of many studies, which proved the biomechanical superiority and the increased pullout strength of cement augmented screws. Inadequate, and sometimes dangerous, cement distribution made the need for development of special implants inevitable. Pedicle screws with side openings and a central drill hole allow cement augmentation through the implant and increase not only the screw diameter but also the interfacial strength between the three components (screw-cement-bone). Accordingly cement distribution can be affected by the selection of the side openings (size and position). Screws with conical core and distally situated side openings facilitate the development of uniform cement dough.The effects of deteriorated bone density become particularly apparent in cases where spinal instrumentation is needed. Cement augmentation of pedicle screws for better bone purchase became the subject of many studies, which proved the biomechanical superiority and the increased pullout strength of cement augmented screws. Inadequate, and sometimes dangerous, cement distribution made the need for development of special implants inevitable. Pedicle screws with side openings and a central drill hole allow cement augmentation through the implant and increase not only the screw diameter but also the interfacial strength between the three components (screw-cement-bone). Accordingly cement distribution can be affected by the selection of the side openings (size and position). Screws with conical core and distally situated side openings facilitate the development of uniform cement dough.