Publications by authors named "Thomas Vordemvenne"

28 Publications

  • Page 1 of 1

Spongostan Leads to Increased Regeneration of a Rat Calvarial Critical Size Defect Compared to NanoBone and Actifuse.

Materials (Basel) 2021 Apr 14;14(8). Epub 2021 Apr 14.

Molecular Neurobiology, Bielefeld University, Universitätsstrasse 25, 33615 Bielefeld, Germany.

Bone substitute materials are becoming increasingly important in oral and maxillofacial surgery. Reconstruction of critical size bone defects is still challenging for surgeons. Here, we compared the clinically applied organic bone substitute materials NanoBone (nanocrystalline hydroxyapatite and nanostructured silica gel; = 5) and Actifuse (calcium phosphate with silicate substitution; = 5) with natural collagen-based Spongostan™ (hardened pork gelatin containing formalin and lauryl alcohol; = 5) in bilateral rat critical-size defects (5 mm diameter). On topological level, NanoBone is known to harbour nanopores of about 20 nm diameter, while Actifuse comprises micropores of 200-500 µm. Spongostan™, which is clinically applied as a haemostatic agent, combines in its wet form both nano- and microporous topological features by comprising 60.66 ± 24.48 μm micropores accompanied by nanopores of 32.97 ± 1.41 nm diameter. Micro-computed tomography (µCT) used for evaluation 30 days after surgery revealed a significant increase in bone volume by all three bone substitute materials in comparison to the untreated controls. Clearly visual was the closure of trepanation in all treated groups, but granular appearance of NanoBone and Actifuse with less closure at the margins of the burr holes. In contrast, transplantion of Spongostan™ lead to complete filling of the burr hole with the highest bone volume of 7.98 ccm and the highest bone mineral density compared to all other groups. In summary, transplantation of Spongostan™ resulted in increased regeneration of a rat calvarial critical size defect compared to NanoBone and Actifuse, suggesting the distinct nano- and microtopography of wet Spongostan™ to account for this superior regenerative capacity. Since Spongostan™ is a clinically approved product used primarily for haemostasis, it may represent an interesting alternative in the reconstruction of defects in the maxillary region.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ma14081961DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8070843PMC
April 2021

Effects of the first lockdown of the COVID-19 pandemic on the trauma surgery clinic of a German Level I Trauma Center.

Eur J Trauma Emerg Surg 2021 Apr 15. Epub 2021 Apr 15.

Protestant Hospital of Bethel Foundation, Department of Trauma Surgery and Orthopaedics, University Hospital OWL of Bielefeld University, Campus Bielefeld-Bethel, Burgsteig 13, 33617, Bielefeld, Germany.

Purpose: The effects of the first pandemic wave on a German Level I Trauma Center should be evaluated to find ways to redistribute structural, personnel, and financial resources in a targeted manner in preparation for the assumed second pandemic wave.

Methods: We examined the repercussions of the first wave of the pandemic on the trauma surgery clinic of a Level I Trauma Center and compared the data with data from 58 other trauma clinics. The results could aid in orientating the distribution of structural, financial, and human resources (HR) during the second wave. The period between March 16 and April 30, 2020 was compared with the data over the same period during 2019. Information was collected from the HR department, central revenue management, and internal documentation.

Results: The proportion of trauma surgical patients in the emergency room decreased by 22%. The number of polytrauma cases increased by 53%. Hospital days of trauma surgery patients in the intensive and intermediate care wards increased by 90%. The number of operations decreased by 15%, although the operating time outside of normal working hours increased by 44%. Clinics with more than 600 beds recorded a decrease in cases and emergencies by 8 and 9%, respectively, while the Trauma Center showed an increase of 19 and 12%. The results reflect the importance of level I trauma centers in the lockdown phase.

Conclusion: To reduce the risk of an increased burden on the healthcare infrastructure, it suggests the care of trauma and COVID-19 patients should be separated locally, when possible.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00068-021-01635-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8048337PMC
April 2021

Removal of cement-augmented screws in distal femoral fractures and the effect of retained screws and cement on total knee arthroplasty: a biomechanical investigation.

J Orthop Traumatol 2021 Feb 27;22(1). Epub 2021 Feb 27.

AO Research Institute Davos, Clavadelerstrasse 8, 7270, Davos, Switzerland.

Background: Given the increasing number of osteoporotic fractures of the distal femur, screw augmentation with bone cement is an option to enhance implant anchorage. However, in implant removal or revision surgeries, the cement cannot be removed from the distal femur without an extended surgical procedure. Therefore, the aims of this study were to investigate (1) whether cement augmentation has any influence on screw removal and removal torque, and (2) whether the implantation of a femoral component of a knee arthroplasty and its initial interface stability are affected by the remaining screws/cement.

Material And Methods: Eight pairs of fresh-frozen human female cadaveric distal femurs (mean age, 86 years) with a simulated AO/OTA 33 A3 fracture were randomized in paired fashion to two groups and fixed with a distal femoral locking plate using cannulated perforated locking screws. Screw augmentation with bone cement was performed in one of the groups, while the other group received no screw augmentation. Following biomechanical testing until failure (results published separately), the screws were removed and the removal torque was measured. A femoral component of a knee arthroplasty was then implanted, and pull-out tests were performed after cement curing. Interference from broken screws/cement was assessed, and the maximum pull-out force was measured.

Results: The mean screw removal torque was not significantly different between the augmented (4.9 Nm, SD 0.9) and nonaugmented (4.6 Nm, SD 1.3, p = 0.65) screw groups. However, there were significantly more broken screws in in the augmented screw group (17 versus 9; p < 0.001). There was no significant difference in the pull-out force of the femoral component between the augmented (2625 N, SD 603) and nonaugmented (2653 N, SD 542, p = 0.94) screw groups.

Conclusion: The screw removal torque during implant removal surgery does not significantly differ between augmented and nonaugmented screws. In the augmented screw group, significantly more screws failed. To overcome this, the use of solid screws in holes B, C, and G can be considered. Additionally, it is possible to implant a femoral component for knee arthroplasty that retains the initial anchorage and does not suffer from interference with broken screws and/or residual cement.

Level Of Evidence: 5.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s10195-021-00568-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7914321PMC
February 2021

Local bone quality measure and construct failure prediction: a biomechanical study on distal femur fractures.

Arch Orthop Trauma Surg 2021 Feb 15. Epub 2021 Feb 15.

Department of Trauma and Orthopedic Surgery, Protestant Hospital of Bethel Foundation, University Hospital OWL of Bielefeld University, Campus Bielefeld Bethel, Burgsteig 13, 33617, Bielefeld, Germany.

Introduction: The aim of this investigation was to better understand the differences in local bone quality at the distal femur and their correlation with biomechanical construct failure, with the intention to identify regions of importance to optimize implant anchorage.

Materials And Methods: Seven fresh-frozen female femurs underwent high-resolution peripheral quantitative computed tomography (HR-pQCT) to determine bone mineral density (BMD) within three different regions of interest (distal, intermedium, and proximal) at the distal femur. In addition, local bone quality was assessed by measuring the peak torque necessary to break out the trabecular bone along each separate hole of a locking compression plate (LCP) during its instrumentation. Finally, biomechanical testing was performed using cyclic axial loading until failure in an AO/OTA 33 A3 fracture model.

Results: Local BMD was highest in the distal region. This was confirmed by the measurement of local bone quality using DensiProbe. The most distal holes represented locations with the highest breakaway torque resistance, with the holes on the posterior side of the plate indicating higher values than those on its anterior side. We demonstrated strong correlation between the cycles to failure and local bone strength (measured with DensiProbe) in the most distal posterior screw hole, having the highest peak torque.

Conclusion: The local bone quality at the distal femur indicates that in plated distal femur fractures the distal posterior screw holes seem to be the key ones and should be occupied. Measurement of the local bone strength with DensiProbe is one possibility to determine the risk of construct failure, therefore, thresholds need to be defined.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00402-021-03782-7DOI Listing
February 2021

Grave thoraco-intestinal complication secondary to an undetected traumatic rupture of the diaphragm: a case report.

Eur J Med Res 2021 Feb 8;26(1):19. Epub 2021 Feb 8.

Department of General and Visceral Surgery, University Hospital OWL of the University Bielefeld, campus Bielefeld-Bethel, Bielefeld, Germany.

Background: Diaphragmatic lesions as a result of blunt or penetrating trauma are challenging to detect in the initial trauma setting. This is especially true when diaphragmatic trauma is part of a polytrauma. Complications of undetected diaphragmatic defects with incarcerating bowel are rare, but as in our patient can be serious.

Case Presentation: A 57-year-old female presented to the Emergency Room of our Hospital in a critical condition with 3 days of increasing abdominal pain. The initial clinical examination showed peritonism with tinkling peristaltic bowel sounds of mechanical obstruction. A thoraco-abdominal CT scan demonstrated colon prolapsed through the left diaphragmatic center with a large sero-pneumothorax under tension. As the patient was hemodynamically increasingly unstable with developing septic shock, an emergency laparotomy was performed. After retraction of the left colon, which had herniated through a defect of the tendinous center of the left diaphragm and was perforated due to transmural ischemia, large amounts of feces and gas discharged from the left thorax. A left hemicolectomy resulting in a Hartmann-type procedure was performed. A fully established pleural empyema required meticulous debridement and lavage conducted via the 7-10 cm in diameter phrenic opening followed by a diaphragmatic defect reconstruction. Due to pneumonia and recurring pleural empyema redo-debridement of the left pleural space via thoracotomy were required. The patient was discharged on day 56. A thorough history of possible trauma revealed a bicycle-fall trauma 7 months prior to this hospitalization with a surgically stabilized fracture of the left femur and conservatively treated fractures of ribs 3-9 on the left side.

Conclusion: This is the first report on a primarily established empyema at the time of first surgical intervention for feco-pneumothorax secondary to delayed diagnosed diaphragmatic rupture following abdomino-thoracic blunt trauma with colic perforation into the pleural space, requiring repetitive surgical debridement in order to control local and systemic sepsis. Thorough investigation should always be undertaken in cases of blunt abdominal and thoracic trauma to exclude diaphragmatic injury in order to avoid post-traumatic complications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s40001-021-00488-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7871382PMC
February 2021

Differentiation of Traumatic Osteoporotic and Non-Osteoporotic Vertebral AO A3 Fractures by Analyzing the Posterior Edge Morphology-A Retrospective Feasibility Study.

J Clin Med 2020 Dec 2;9(12). Epub 2020 Dec 2.

Department of Trauma, Hand and Reconstructive Surgery, University Hospital Muenster, Albert-Schweitzer-Campus 1, Building W1, 48149 Muenster, Germany.

Background: Differentiation between traumatic osteoporotic and non-osteoporotic vertebral fractures is crucial for optimal therapy planning. We postulated that the morphology of the posterior edge of the cranial fragment of A3 vertebral fractures is different in these entities. Therefore, the purpose of this study is to develop and validate a simple method to differentiate between osteoporotic and non-osteoporotic A3 vertebral fractures by morphological analysis.

Methods: A total of 86 computer tomography scans of AO Type A3 (cranial burst) vertebral body fractures (52 non-osteoporotic, 34 osteoporotic) were included in this retrospective study. Posterior edge morphology was analyzed using the sagittal paramedian slice with the most prominent shaped bulging. Later, the degree of bulging of the posterior edge fragment was quantified using a geometric approach. Additionally, the Hounsfield units of the broken vertebral body, the vertebra above, and the vertebra below the fracture were measured.

Results: We found significant differences in the extent of bulging comparing osteoporotic and non-osteoporotic fractures in our cohort. Using the presented method, sensitivity was 100%, specificity was 96%. The positive predictive value (PPV) was 94%. In contrast, by evaluating the Hounsfield units, sensitivity was 94%, specificity 94% and the PPV was 91%.

Conclusions: Our method of analysis of the bulging of the dorsal edge fragment in traumatic cranial burst fractures cases allows, in our cases, a simple and valid differentiation between osteoporotic and non-osteoporotic fractures. Further validation in a larger sample, including dual-energy X-ray absorptiometry (DXA) measurements, is necessary.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/jcm9123910DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7760871PMC
December 2020

Analysis of risk factors in thoracic trauma patients with a comparison of a modern trauma centre: a mono-centre study.

World J Emerg Surg 2020 07 31;15(1):45. Epub 2020 Jul 31.

Division of Accident & Emergency, Protestant Hospital of Bethel Foundation, Burgsteig, 13, Bielefeld, Germany.

Objectives: Thoracic trauma (TT) is the third most common cause of death after abdominal injury and head trauma in polytrauma patients. Its management is still a very challenging task. The purpose of this study was to analyse the risk factors affecting the outcome in a high-volume trauma centre and the efficacy of a specialised trauma team in level 1 trauma centres.

Patients And Methods: Between January 2003 and December 2012, data of all patients admitted to the accident and emergency (A&E) department were prospectively collected at the German Trauma Registry (GTR) and thereafter retrospectively analysed. Patients with chest trauma, an Injury Severity Score (ISS) ≥ 18 and an Abbreviated Injury Scale (AIS) > 2 in more than one body region were included. Patients were divided into two groups: group I included patients presenting with thoracic trauma between January 2003 and December 2007. The results of this group were compared with the results of another group (group II) in a later 5-year period (Jan. 2008-Dec. 2012). Univariate and multivariate analyses were performed, and differences with p < 0.05 were considered statistically significant.

Results: There were 630 patients (56%) with thoracic trauma. A total of 540 patients (48%) had associated extrathoracic injuries. Group I consisted of 285 patients (197 male, mean age 46 years). Group II consisted of 345 patients (251 male, mean age 49 years). Overall 90-day mortality was 17% (n = 48) in group I vs. 9% (n = 31) in group II (p = 0.024). Complication rates were higher in group I (p = 0.019). Higher Injury Severity Scores (ISSs) and higher Abbreviated Injury Acale (AIS) scores in the thoracic region yielded a higher rate of mortality (p < 0.0001). Young patients (< 40 years) were frequently exposed to severe thoracic injury but showed lower mortality rates (p = 0.014). Patients with severe lung contusions (n = 94) (15%) had higher morbidity and mortality (p < 0.001). Twenty-three (8%) patients underwent emergency thoracotomy in group I vs. 14 patients (4%) in group II (p = 0.041). Organ replacement procedures were needed in 18% of patients in group I vs. 31% of patients in group II (p = 0.038).

Conclusions: The presence of severe lung contusion, a higher ISS and AIS score and advanced age are independent risk factors that are directly related to a higher mortality rate. Management of blunt chest trauma with corrective chest tube insertion, optimal pain control and chest physiotherapy results in good outcomes in the majority of patients. Optimal management with better survival rates is achievable in specialised centres with multidisciplinary teamwork and the presence of thoracic surgical experience.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13017-020-00324-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7393329PMC
July 2020

Bone Regeneration: A Novel Osteoinductive Function of Spongostan by the Interplay between Its Nano- and Microtopography.

Cells 2020 03 7;9(3). Epub 2020 Mar 7.

Molecular Neurobiology, Bielefeld University, Universitätsstrasse 25, 33615 Bielefeld, Germany.

Scaffold materials for bone regeneration are crucial for supporting endogenous healing after accidents, infections, or tumor resection. Although beneficial impacts of microtopological or nanotopological cues in scaffold topography are commonly acknowledged, less consideration is given to the interplay between the microscale and nanoscale. Here, micropores with a 60.66 ± 24.48 µm diameter ordered by closely packed collagen fibers are identified in pre-wetted Spongostan, a clinically-approved collagen sponge. On a nanoscale level, a corrugated surface of the collagen sponge is observable, leading to the presence of 32.97 ± 1.41 nm pores. This distinct micro- and nanotopography is shown to be solely sufficient for guiding osteogenic differentiation of human stem cells in vitro. Transplantation of Spongostan into a critical-size calvarial rat bone defect further leads to fast regeneration of the lesion. However, masking the micro- and nanotopographical cues using SiO nanoparticles prevents bone regeneration in vivo. Therefore, we demonstrate that the identified micropores allow migration of stem cells, which are further driven towards osteogenic differentiation by scaffold nanotopography. The present findings emphasize the necessity of considering both micro- and nanotopographical cues to guide intramembranous ossification, and might provide an optimal cell- and growth-factor-free scaffold for bone regeneration in clinical settings.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/cells9030654DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7140719PMC
March 2020

Complex biomechanical properties of non-augmented and augmented pedicle screws in human vertebrae with reduced bone density.

BMC Musculoskelet Disord 2020 Mar 6;21(1):151. Epub 2020 Mar 6.

University Hospital Münster, Department of Trauma, Hand and Reconstructive Surgery, Albert-Schweitzer-Campus 1, 48149, Münster, Germany.

Background: In osteoporotic bone, the quality of the bone-to-implant interface is decreased, which may lead to early implant failure. Screw anchorage can be improved by augmentation. This effect is mainly investigated with a pull-out test. To our knowledge, the effect of cement augmentation in an in vivo physiological setup focusing on screw movement has not been investigated to date. The aim of this work was to investigate and compare augmented and native screw behavior in a physiologically related setup.

Methods: Twelve fresh-frozen human lumbar vertebrae were divided into two groups. Each vertebra was bilaterally instrumented with either non-augmented or augmented pedicle screw systems and loaded in a recently developed test setup that provided cyclic conditions comparable to a physiological gait. The cyclic loading should test the primary implant stability, comparable to the postoperative period of two months in a worst-case scenario in the absence of osseous remodeling. Screws were tracked optically, and screw movement and failure patterns were observed.

Results: Mutual influence between the left and right sides resulted in a successive, rather than simultaneous, failure. Augmentation of the screws in vertebrae with poor bone quality reduced screw subsidence and thus improved the rigidity of the screw-to-implant interface by up to six-fold. The non-augmented condition was significantly related to early screw failure.

Conclusions: Pedicle screw system failure involves a complex bilateral-coupled mechanism. The cyclic loading based on physiological conditions during walking has allowed the postoperative conditions and clinical failure mechanisms to be simulated in vitro and clarified. Future implant systems should be investigated with a physiologically related setup.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12891-020-3158-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7060638PMC
March 2020

A Role for NF-κB in Organ Specific Cancer and Cancer Stem Cells.

Cancers (Basel) 2019 May 11;11(5). Epub 2019 May 11.

Department of Cell Biology, Bielefeld University, Universitätsstrasse 25, 33615 Bielefeld, Germany.

Cancer stem cells (CSCs) account for tumor initiation, invasiveness, metastasis, and recurrence in a broad range of human cancers. Although being a key player in cancer development and progression by stimulating proliferation and metastasis and preventing apoptosis, the role of the transcription factor NF-κB in cancer stem cells is still underestimated. In the present review, we will evaluate the role of NF-κB in CSCs of glioblastoma multiforme, ovarian cancer, multiple myeloma, lung cancer, colon cancer, prostate cancer, as well as cancer of the bone. Next to summarizing current knowledge regarding the presence and contribution of CSCs to the respective types of cancer, we will emphasize NF-κB-mediated signaling pathways directly involved in maintaining characteristics of cancer stem cells associated to tumor progression. Here, we will also focus on the status of NF-κB-activity predominantly in CSC populations and the tumor mass. Genetic alterations leading to NF-κB activity in glioblastoma, ependymoma, and multiple myeloma will be discussed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/cancers11050655DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6563002PMC
May 2019

Natural and synthetic nanopores directing osteogenic differentiation of human stem cells.

Nanomedicine 2019 04 14;17:319-328. Epub 2019 Feb 14.

Department of Cell Biology, Bielefeld University, Bielefeld, Germany; Molecular Neurobiology, Bielefeld University, Bielefeld, Germany; Bielefeld Institute for Nanoscience (BINAS), Bielefeld University, Bielefeld, Germany. Electronic address:

Bone regeneration is a highly orchestrated process crucial for endogenous healing procedures after accidents, infections or tumor therapy. Changes in surface nanotopography are known to directly affect the formation of osteogenic cell types, although no direct linkage to the endogenous nanotopography of bone was described so far. Here we show the presence of pores of 31.93 ± 0.97 nm diameter on the surface of collagen type I fibers, the organic component of bone, and demonstrate these pores to be sufficient to induce osteogenic differentiation of adult human stem cells. We further applied SiO nanoparticles thermally cross-linked to a nanocomposite to artificially biomimic 31.93 ± 0.97 nm pores, which likewise led to in vitro production of bone mineral by adult human stem cells. Our findings show an endogenous mechanism of directing osteogenic differentiation of adult stem cells by nanotopological cues and provide a direct application using SiO nanocomposites with surface nanotopography biomimicking native bone architecture.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.nano.2019.01.018DOI Listing
April 2019

Treatment of Odontoid Fractures: Recommendations of the Spine Section of the German Society for Orthopaedics and Trauma (DGOU).

Global Spine J 2018 Sep 7;8(2 Suppl):12S-17S. Epub 2018 Sep 7.

Schön Klinik Nürnberg Fürth, Fürth, Germany.

Study Design: Narrative review.

Objective: To establish recommendations for the treatment of odontoid fractures based on current literature and the knowledge of the experts of the Spine Section of the German Society for Orthopaedics and Trauma (DGOU).

Methods: Narrative review of the literature. Analyzing treatment algorithms of German trauma and spine centers as members of the Spine Section of the German Society for Orthopaedics and Trauma (DGOU).

Results: There are many influencing factors leading to appropriate treatment of odontoid fractures such as age, bone quality, arthrosis, classification, and type of the fracture. Conservative nonoperative treatment is appropriate for stable undislocated displaced odontoid fractures. Anterior osteosynthesis with 1 or 2 screws leads to good results in the classical unstable type II odontoid fracture in patients with good bone quality. However, modifiers have been identified by the working group leading to higher complication and failure rates. For these cases, more stable constructs and/or posterior approaches are indicated.

Conclusions: Operation seems to be standard treatment for odontoid fractures. However, in the aged population, conservative treatment should be considered as morbidity and mortality rise significantly in the group of >75 years. Conservative treatment may also be started within stable nondislocated fractures, but then regular controls have to be performed. If operation is indicated, many influencing factors have to be considered for appropriate approach and technique. The classification of Anderson and D'Alonzo is still standard. To create an adequate treatment algorithm, dislocation displacement and instability have to be identified. Stable odontoid fractures are treated conservatively non-operatively, but if so regular controls have to be performed. Unstable and/or dislocated displaced odontoid fractures are treated by anterior osteosynthesis with 1 or 2 screws. The technique is demanding and leads to elevated complication and failure rates if modifiers are apparent. In these cases, posterior instrumentation or fusion of C1 and C2 is favorable. In the aged population (>80 years), operative therapy is critical as postoperative morbidity complication and mortality rates rise significantly. As there is still some bias in the treatment algorithms, the working group recommends establishment of a prospective study to result in more objective statements.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/2192568218768227DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6130105PMC
September 2018

Biomechanical characteristics of pedicle screws in osteoporotic vertebrae-comparing a new cadaver corpectomy model and pure pull-out testing.

J Orthop Res 2017 01 6;35(1):167-174. Epub 2016 Apr 6.

Department of Trauma and Orthopedic Surgery, Evangelical Hospital Bielefeld, Burgsteig 13, 33617, Bielefeld, Germany.

Currently, evaluation of the stability of spinal instrumentations often focuses on simple pull-out or cyclic loading. However, the loading characteristics and the specimen alignment rarely simulate physiological loading conditions, or the clinical situation itself. The purpose of this study was to develop an alternative setup and parameters to compare static and dynamic characteristics of pedicle screws at the bone-implant interface in lumbar osteoporotic cadavers. A corpectomy model development was based on ASTM-1717 standard, allowing a deflection of the cranial and caudal element under loading. Twelve human osteoporotic vertebrae (L1-L4) were analyzed for morphological CT-data and T-Score. For group A (n = 6) loads were simulated as in vivo measurements during walking, representing 2 months postoperatively. A subsequent pull-out was performed. Group B (n = 6) was tested with pure pull-out. Screw loosening at the tip/head was optically measured and analyzed with respect to clinical patterns. Correlations between CT-data, T-Score, and in vitro parameters were determined. For group A, the subsidence for the head/tip was measured towards the upper/lower endplate, resulting in visible deflections. The progress of the subsidence was greatest within the first and last cycles until failure. The predominant patterns were pure rotation and toggling. However, the pull-out between groups was not significantly different. Pedicle-angle and cyclic-subsidence correlated with R = 0.806/0.794. T-Score and pull-out correlated only in group A. With the corpectomy setup, clinically observed wipe effects and a loss of correction could be simulated. The presented parameters facilitate analysis of the complex changing load distributions and interactions between the left and right bone-implant interface. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:167-174, 2017.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jor.23237DOI Listing
January 2017

Answer to the Letter to the Editor of A. Goel concerning "biomechanical evaluation of the Facet Wedge: a refined technique for facet fixation" by R. Hartensuer et al.; Eur Spine J (2014) 23:2321-2329.

Eur Spine J 2015 Feb 11;24(2):405. Epub 2014 Dec 11.

Department of Trauma-, Hand- and Reconstructive Surgery, Wilhelms-University of Muenster, Albert-Schweitzer-Campus 1, W1, 48149, Münster, Germany,

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00586-014-3712-1DOI Listing
February 2015

How does free rod-sliding affect the posterior instrumentation for a dynamic stabilization using a bovine calf model?

Spine (Phila Pa 1976) 2015 Feb;40(3):E133-40

*Department of Trauma, Hand and Reconstructive Surgery, and †Institute for Experimental Musculoskeletal Medicine, University of Muenster, Muenster, Germany; and ‡ACES GmbH, Esslingen, Germany.

Study Design: A biomechanical cadaveric study in lumbar calf spine.

Objective: Evaluation of the effects of selected degrees of freedom (df) on the dynamic stabilization of the spine in terms of segmental range of motion (RoM), center of rotation (CoR), and implant loadings.

Summary Of Background Data: For dorsal stabilization, rigid implant systems are becoming increasingly complemented by numerous dynamic systems based on pedicle screws and varying df. However, it is still unclear which df is most suitable to accomplish a physiologically related dynamic stabilization, and which loadings are induced to the implants. Human and calf specimens are reported to show certain similarities in their biomechanics. Young healthy calf specimens are not degenerated and show less interindividual differences than elderly human specimens. However, the existing differences between species limit the conclusions in a preclinical setting.

Methods: Six calf specimens from level L3-L4 were analyzed in flexion and extension with a 6-df robotic spine simulator. A clinical functional radiological examination tool was used and parameters such as RoM, CoR, and implant loadings were determined for 6 configurations: (1) intact, (2) defect, (3) rigid fixation, (4) free craniocaudal (CC) rod-sliding, (5) free polyaxiality, and (6) combined free rod-sliding and free polyaxiality. The location of the CoR was determined relative to vertebral body dimensions. A CoR repositioning was defined as sufficient when its median differed less than 5% of the vertebral body dimensions.

Results: Free rod-sliding in the CC direction restored the CoR from the defect back to the intact condition. The RoM could be significantly reduced to approximately 1/2 of the intact condition. Compared with the rigid condition, the implant bending moments increased from 0.3/-0.8 Nm (flexion/extension) to 1.3/-1.2 Nm for the free CC rod-sliding condition.

Conclusion: Free CC rod-sliding restores the intact conditions of the tested kinematic parameters most suitably and at the same time reduces the RoM. Stabilization toward the intact condition could decrease the risk of stress shielding and the progress of segment degeneration.

Level Of Evidence: N/A.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/BRS.0000000000000702DOI Listing
February 2015

Biomechanical evaluation of the Facet Wedge: a refined technique for facet fixation.

Eur Spine J 2014 Nov 26;23(11):2321-9. Epub 2014 Aug 26.

Department of Trauma-, Hand- and Reconstructive Surgery, Wilhelms-University of Muenster, Albert-Schweitzer-Campus 1, W1, 48149, Münster, Germany,

Purpose: Purpose of this paper is to evaluate the primary stability of a new approach for facet fixation the so-called Facet Wedge (FW) in comparison with established posterior fixation techniques like pedicle screws (PS) and translaminar facet screws (TLS) with and without anterior cage interposition.

Methods: Twenty-four monosegmental fresh frozen non-osteoporotic human motion segments (L2-L3 and L4-L5) were tested in a two-arm biomechanical study using a robot-based spine tester. Facet Wedge was compared with pedicle screws and translaminar screws as a stand-alone device and in combination with an anterior fusion cage.

Results: Pedicle screws, FW and translaminar screws could stabilize an intact motion segment effectively. Facet Wedge was comparable to PS for lateral bending, extension and flexion and slightly superior for axial rotation. Facet Wedge showed a superior kinematic capacity compared to translaminar screws.

Conclusions: Facet Wedge offers a novel posterior approach in achieving primary stability in lumbar spinal fixation. The results of the present study showed that the Facet Wedge has a comparable primary stability to pedicle screws and potential advantages over translaminar screws.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00586-014-3533-2DOI Listing
November 2014

Management of an extended clivus fracture: a case report.

BMC Res Notes 2013 Dec 23;6:554. Epub 2013 Dec 23.

Department for Trauma-, Reconstructive- and Handsurgery, University Muenster, Albert-Schweitzer-Campus 1 Gebäude W1, Münster 48149, Germany.

Background: Clivus fractures are highly uncommon. The classification by Corradino et al. divides the different lesions in longitudinal, transverse and oblique fractures. Longitudinal types are associated with the highest mortality rate between 67 - 80%. Clivus fractures are often found after high velocity trauma, especially traffic accidents and falls. The risk of neurologic lesions is high, because of the anatomic proximity to neurovascular structures like the brainstem, the vertebrobasilar artery, and the cranial nerves. Longitudinal clivus fractures have a special risk of causing entrapment of the basilar artery and thus ischemia of the brainstem.

Case Presentation: This lesion in our patient was a combination-fracture of the craniocervical junction with a transverse clivus fracture. In this case, the primary closed reduction of the clivus fracture and the immobilization with a halo device was the therapy of choice and led to consolidation of the fracture.

Conclusion: Therapy advices and examples in the literature are scarce. We present a patient with a clivus fracture, who could be well treated by a halo device. Through detailed research of the literature a therapy algorithm has been developed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1756-0500-6-554DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3878031PMC
December 2013

Biomechanical evaluation of combined short segment fixation and augmentation of incomplete osteoporotic burst fractures.

BMC Musculoskelet Disord 2013 Dec 21;14:360. Epub 2013 Dec 21.

Department of Trauma-, Hand-, and Reconstructive Surgery, Westfälische Wilhelms-University Münster, Albert-Schweitzer-Campus 1, W1, Münster 48149, Germany.

Background: Treating traumatic fractures in osteoporosis is challenging. Multiple clinical treatment options are found in literature. Augmentation techniques are promising to reduce treatment-related morbidity. In recent years, there have been an increasing number of reports about extended indication for augmentation techniques. However, biomechanical evaluations of these techniques are limited.

Methods: Nine thoracolumbar osteoporotic spinal samples (4 FSU) were harvested from postmortem donors and immediately frozen. Biomechanical testing was performed by a robotic-based spine tester. Standardized incomplete burst fractures were created by a combination of osteotomy-like weakening and high velocity compression using a hydraulic material testing apparatus. Biomechanical measurements were performed on specimens in the following conditions: 1) intact, 2) fractured, 3) bisegmental instrumented, 4) bisegmental instrumented with vertebroplasty (hybrid augmentation, HA) and 5) stand-alone vertebroplasty (VP). The range of motion (RoM), neutral zone (NZ), elastic zone (EZ) and stiffness parameters were determined. Statistical evaluation was performed using Wilcoxon signed-rank test for paired samples (p = 0.05).

Results: Significant increases in RoM and in the NZ and EZ (p < 0.005) were observed after fracture production. The RoM was decreased significantly by applying the dorsal bisegmental instrumentation to the fractured specimens (p < 0.005). VP reduced fractured RoM in flexion but was still increased significantly (p < 0.05) above intact kinematic values. NZ stiffness (p < 0.05) and EZ stiffness (p < 0.01) was increased by VP but remained lower than prefracture values. The combination of short segment instrumentation and vertebroplasty (HA) showed no significant changes in RoM and stiffness in NZ in comparison to the instrumented group, except for significant increase of EZ stiffness in flexion (p < 0.05).

Conclusions: Stand-alone vertebroplasty (VP) showed some degree of support of the anterior column but was accompanied by persistent traumatic instability. Therefore, we would advocate against using VP as a stand-alone procedure in traumatic fractures. HA did not increase primary stability of short segment instrumentation. Some additional support of anterior column and changes of kinematic values of the EZ may lead one to suppose that additive augmentation may reduce the load of dorsal implants and possibly reduce the risk of implant failure.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1471-2474-14-360DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3878408PMC
December 2013

Radiographic and safety details of vertebral body stenting: results from a multicenter chart review.

BMC Musculoskelet Disord 2013 Aug 8;14:233. Epub 2013 Aug 8.

Background: Up to one third of BKP treated cases shows no appreciable height restoration due to loss of both restored height and kyphotic realignment after balloon deflation. This shortcoming has called for an improved method that maintains the height and realignment reached by the fully inflated balloon until stabilization of the vertebral body by PMMA-based cementation. Restoration of the physiological vertebral body height for pain relief and for preventing further fractures of adjacent and distant vertebral bodies must be the main aim for such a method. A new vertebral body stenting system (VBS) stabilizes the vertebral body after balloon deflation until cementation. The radiographic and safety results of the first 100 cases where VBS was applied are presented.

Methods: During the planning phase of an ongoing international multicenter RCT, radiographic, procedural and followup details were retrospectively transcribed from charts and xrays for developing and testing the case report forms. Radiographs were centrally assessed at the institution of the first/senior author.

Results: 100 patients (62 with osteoporosis) with a total of 103 fractured vertebral bodies were treated with the VBS system. 49 were females with a mean age of 73.2 years; males were 66.7 years old. The mean preoperative anterior-middle-posterior heights were 20.3-17.6-28.0 mm, respectively. The mean local kyphotic angle was 13.1°. The mean preoperative Beck Index (anterior edge height/posterior edge height) was 0.73, the mean alternative Beck Index (middle height/posterior edge height) was 0.63. The mean postoperative heights were restored to 24.5-24.6-30.4 mm, respectively. The mean local kyphotic angle was reduced to 8.9°. The mean postoperative Beck Index was 0.81, the mean alternative one was 0.82. The overall extrusion rate was 29.1%, the symptomatic one was 1%. In the osteoporosis subgroup there were 23.8% extrusions. Within the three months followup interval there were 9% of adjacent and 4% of remote new fractures, all in the osteoporotic group.

Conclusions: VBS showed its strengths especially in realignment of crush and biconcave fractures. Given that fracture mobility is present, the realignment potential is sound and increases with the severity of preoperative vertebral body deformation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1471-2474-14-233DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3751159PMC
August 2013

[First aid and management of multiple trauma: in-hospital trauma care].

Anasthesiol Intensivmed Notfallmed Schmerzther 2012 Nov 12;47(11-12):716-23. Epub 2012 Dec 12.

Klinik für Anästhesiologie, operative Intensivmedizin und Schmerztherapie am Universitäts klinikum Münster.

Injuries remain the leading cause of death in children and young adults. Management of multiple trauma patients has improved in recent years by quality initiatives (trauma network, S3 guideline "Polytrauma"). On this basis, strong links with preclinical management, structured treatment algorithms, training standards (ATLS®), clear diagnostic rules and an established risk- and quality management are the important factors of a modern emergency room trauma care. We describe the organizational components that lead to successful management of trauma in hospital.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1055/s-0032-1331369DOI Listing
November 2012

Retrograde nail for tibiotalocalcaneal arthrodesis as a limb salvage procedure for open distal tibia and talus fractures with severe bone loss.

J Foot Ankle Surg 2012 Sep-Oct;51(5):675-9. Epub 2012 May 22.

Department of Trauma, Hand, and Reconstructive Surgery, University Hospital, Muenster, Germany.

The treatment of complex fractures of the distal tibia, ankle, and talus with soft tissue damage, bone loss, and nonreconstructable joints for which the optimal timing for reduction and fixation has been missed is challenging. In such cases primary arthrodesis might be a treatment option. We report a series of multi-injured patients with severe soft tissue damage and bone loss, who were treated with a retrograde tibiotalocalcaneal arthrodesis nail as a minimally invasive treatment option for limb salvage. After a median follow-up of 5.4 years, all patients returned to their former profession. The ankle and bone fusion was complete, with moderate functional results and quality of life. Calcaneotibial arthrodesis using a retrograde nail is a good treatment option for nonreconstructable fractures of the ankle joint with severe bone loss and poor soft tissue quality in selected patients with multiple injuries, in particular, those involving both lower extremities, as a salvage procedure.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1053/j.jfas.2012.04.015DOI Listing
January 2013

Experimentally induced incomplete burst fractures - a novel technique for calf and human specimens.

BMC Musculoskelet Disord 2012 Mar 25;13:45. Epub 2012 Mar 25.

Department of Trauma-, Hand-, and Reconstructive Surgery, Westfälische Wilhelms-University Münster, Waldeyerstrasse 1, Münster 48149, Germany.

Background: Fracture morphology is crucial for the clinical decision-making process preceding spinal fracture treatment. The presented experimental approach was designed in order to ensure reproducibility of induced fracture morphology.

Results: The presented method resulted in fracture morphology, found in clinical classification systems like the Magerl classification. In the calf spine samples, 70% displayed incomplete burst fractures corresponding to type A3.1 and A3.2 fractures. In all human samples, superior incomplete burst fractures (Magerl A3.1) were identified by an independent radiologist and spine surgeon.

Conclusions: The presented set up enables the first experimental means to reliably model and study distinct incomplete burst fracture patterns in an in vitro setting. Thus, we envisage this protocol to facilitate further studies on spine fracture treatment of incomplete burst fractures.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1471-2474-13-45DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3326708PMC
March 2012

Evaluation of a robot-assisted testing system for multisegmental spine specimens.

J Biomech 2012 May 3;45(8):1457-62. Epub 2012 Mar 3.

Department of Trauma, Hand and Reconstructive Surgery, University of Muenster, Albert-Schweitzer Campus 1, 48149 Münster, Germany.

Mono- and multi-segmental testing methods are required to identify segmental motion patterns and evaluate the biomechanical behaviour of the spine. This study aimed to evaluate a new testing system for multisegmental specimens using a robot combined with an optical motion analysis system. After validation of the robotic system for accuracy, two groups of calf specimens (six monosegmental vs. six multisegmental) were mounted and the functional unit L3-4 was observed. Using rigid body markers, range of motion (ROM), elastic zone (EZ) and neutral zone (NZ), as well as stiffness properties of each functional spine unit (FSU) was acquired by an optical motion capture system. Finite helical axes (FHA) were calculated to analyse segmental movements. Both groups were tested in flexion and extension. A pure torque of 7.5 Nm was applied. Statistical analyses were performed using the Mann-Whitney U-test. Repeatability of robot positioning was -0.001±0.018 mm and -0.025±0.023° for translations and rotations, respectively. The accuracy of the optical system for the proposed set-up was 0.001±0.034 mm for translations and 0.075±0.12° for rotations. No significant differences in mean values and standard deviations of ROM for L3-4 compared to literature data were found. A robot-based facility for testing multisegmental spine units combined with a motion analysis system was proposed and the reliability and reproducibility of all system components were evaluated and validated. The proposed set-up delivered ROM results for mono- and multi-segmental testing that agreed with those reported in the literature. Representing the FHA via piercing points determined from ROM was the first attempt showing a relationship between ROM and FHA, which could facilitate the interpretation of spine motion patterns in the future.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jbiomech.2012.02.013DOI Listing
May 2012

Cooperative effects in differentiation and proliferation between PDGF-BB and matrix derived synthetic peptides in human osteoblasts.

BMC Musculoskelet Disord 2011 Nov 21;12:263. Epub 2011 Nov 21.

Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Germany.

Background: Enhancing osteogenic capabilities of bone matrix for the treatment of fractures and segmental defects using growth factors is an active area of research. Recently, synthetic peptides like AC- 100, TP508 or p-15 corresponding to biologically active sequences of matrix proteins have been proven to stimulate bone formation. The platelet-derived growth factor (PDGF) BB has been identified as an important paracrine factor in early bone healing. We hypothesized that the combined use of PDGF-BB with synthetic peptides could result in an increase in proliferation and calcification of osteoblast-like cells.

Methods: Osteoblast-like cell cultures were treated with PDGF and synthetic peptides, singly and as combinations, and compared to non-treated control cell cultures. The cultures were evaluated at days 2, 5, and 10 in terms of cell proliferation, calcification and gene expression of alkaline phosphate, collagen I and osteocalcin.

Results: Experimental findings revealed that the addition of PDGF, p-15 and TP508 and combinations of PDGF/AC-100, PDGF/p-15 and PDGF/TP508 resulted in an increase in proliferating osteoblasts, especially in the first 5 days of cultivation. Proliferation did not significantly differ between single factors and factor combinations (p > 0.05). The onset of calcification in osteoblasts occurred earlier and was more distinct compared to the corresponding control or PDGF stimulation alone. Significant difference was found for the combined use of PDGF/p-15 and PDGF/AC-100 (p < 0.05).

Conclusions: Our findings indicate that PDGF exhibits cooperative effects with synthetic peptides in differentiation and proliferation. These cooperative effects cause a significant early calcification of osteoblast-like cells (p < 0.05). We suggest the combination of synthetic peptides and PDGF as a potential clinical approach for accelerating bone healing or coating osteosynthesis materials.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1471-2474-12-263DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3231994PMC
November 2011

A method to perform spinal motion analysis from functional X-ray images.

J Biomech 2011 Jun 17;44(9):1740-6. Epub 2011 Apr 17.

Department of Trauma, Hand and Reconstructive Surgery, University of Muenster, Germany.

Identifying spinal instability is an important aim for proper surgical treatment. Analysis of functional X-ray images delivers measurements of the range of motion (RoM) and the center of rotation (CoR). In today's practice, CoR determination is often omitted, due to the lack of accurate methods. The aim of this work was to investigate the accuracy of a new analysis software (FXA™) based on an in vitro experiment. Six bovine spinal specimens (L3-4) were mounted in a robot (KR125, Kuka). CoRs were predefined by locking the robot actuator tool center point to the estimated position of the physiologic CoR and taking a baseline X-ray. Specimens were deflected to various RoM(preset) flexion/extension angles about the CoR(preset). Lateral functional radiographs were acquired and specimen movements were recorded using an optical motion tracking system (Optotrak Certus). RoM and CoR errors were calculated from presets for both methods. Prior to the experiment, the FXA™ software was verified with artificially generated images. For the artificial images, FXA™ yielded a mean RoM-error of 0.01 ± 0.03° (bias ± standard deviation). In the experiment, RoM-error of the FXA™-software (deviation from presets) was 0.04 ± 0.13°, and 0.10 ± 0.16° for the Optotrak, respectively. Both correlated with 0.998 (p < 0.001). For RoM < 1.0°, FXA™ determined CoR positions with a bias>20mm. This bias progressively decreased from RoM = 1° (bias = 6.0mm) to RoM = 9° (bias<1.5mm). Under the assumption that CoR location variances <5mm are clinically irrelevant on the lumbar spine, the FXA™ method can accurately determine CoRs for RoMs > 1°. Utilizing FXA™, polysegmental RoMs, CoRs and implant migration measurements could be performed in daily practice.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jbiomech.2011.03.040DOI Listing
June 2011

Influence of synovial fluid on human osteoblasts: an in vitro study.

ScientificWorldJournal 2007 Dec 18;7:2012-20. Epub 2007 Dec 18.

Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Münster, Germany.

Osseous graft healing at the tendon bone interface after anterior cruciate ligament (ACL) reconstruction is unsatisfactory in 10-25%, depending on the evaluation criteria or the kind of graft used for reconstruction. Mechanical as well as biological aspects are currently discussed. Since osteoblasts play an important role in the osseous integration of an ACL graft, we hypothesize that synovial fluid (SF), when entering the bone tunnel, has an inhibitory effect on osteoblasts. In order to verify this hypothesis, human osteoblasts (p3) were incubated in the presence of SF or partially purified SF. Proliferation was assayed using MTT or BrdU assay. Gene expression of osteoblast markers (alkaline phosphatase, collagen I, and osteocalcin) were determined by TaqMan analysis. In the control group, SF was exchanged by fetal calf serum (FCS). The results showed osteoblast proliferation in the presence of SF as well as in partially purified heat-pretreated synovial fluid. Native SF induced alkaline phosphatase and collagen I gene expression. No induction of the osteocalcin gene was observed in the experiment. These results were comparable to that obtained with FCS. These findings suggest that SF stimulated proliferation of osteoblasts in vitro. This effect is mediated, in part, by heat-stable components of SF. In addition, the expression of osteoblast marker genes alkaline phosphatase and collagen I, but not osteocalcin, was induced by SF. Therefore, problems associated with cruciate ligament reconstruction might be due to the inhibition of osteoblast differentiation. If so, this is not a specific attribute of SF, but also applies to serum.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1100/tsw.2007.282DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5901141PMC
December 2007

Proliferating and differentiating effects of three different growth factors on pluripotent mesenchymal cells and osteoblast like cells.

J Orthop Surg Res 2007 Dec 20;2:27. Epub 2007 Dec 20.

Center for Musculoskeletal Surgery, Charité-Universitätsmedizin Berlin, Germany.

Growth factors are in clinical use to stimulate bone growth and regeneration. BMP-2 is used in long bone and spinal surgery, PDGFbb for the treatment of periodontal defects and children with growth hormone receptor deficiency are treated with IGF-I.Aim of the present study was the comparative analysis of the effect of these growth factors released from a local drug delivery system on cells of the osteogenic lineage at differing differentiation stages.The experiments with the mesenchymal cell line C2C12 revealed a proliferating effect of all three growth factors and a differentiating effect of BMP-2 with a dramatic increase in alkaline phosphatase activity. None of the growth factors stimulated cell migration.Human osteoblast like cells showed similar results with an increase in proliferation after stimulation with IGF-I or PDGFbb. The enzymatic activity of alkaline phosphatase was enhanced only in the cells stimulated with BMP-2. This group showed also more mineralized matrix compared to the other groups.In conclusion, the growth factors IGF-I and PDGFbb delivered with a local drug delivery system stimulated cell proliferation, whereas BMP-2 showed a dramatic effect on differentiation on osteoblast precursor cells and osteoblast like cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1749-799X-2-27DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2234398PMC
December 2007

Long-term results after primary microsurgical repair of ulnar and median nerve injuries. A comparison of common score systems.

Clin Neurol Neurosurg 2007 Apr 18;109(3):263-71. Epub 2006 Dec 18.

Department of Trauma and Hand Surgery, University Hospital of Münster, Waldeyerstr. 1, 48149 Münster, Germany.

Objective: The aim of this retrospective study was to analyze the long-term results of primary repair of median and ulnar nerve lesions. Clinical influence factors for nerve reconstruction were investigated. Furthermore, current score systems were inquired and evaluated on their effectiveness to illustrate the success of repair.

Patients And Method: Sixty-five patients with 71 lesions of the median and ulnar nerve were assessed on average 8.2 years after reconstruction. The results were classified according to the DASH (disability of arm, shoulder, and hand) Score, the Rosen's hand protocol and the Highet Scale.

Results: On average the patients regained 70% of their original hand function (evaluated by Rosen Score: median nerve 2.2/for ulnar nerve 1.92 out of 3.0). Although we noticed inferior motor recovery in ulnar nerve lesions, no significant differences between the overall results of both nerves were observed. Neither accompanying artery and flexor tendon injuries nor the suture technique influenced the recovery. The age of the patient was confirmed as an important influence factor. The results of the DASH Score, Rosen Score and Highet Score correlated significantly.

Conclusion: For a sufficient outcome measurement we underline the importance of evaluation of patient's estimation of their impact on their activities of daily living. For this a combination of the functional Rosen Score and the DASH Score is suggested.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.clineuro.2006.11.006DOI Listing
April 2007