Biomedical subjects

A J Verbout

Publications and source records attributed to A J Verbout.

At least 19 recordsLinked to original sources

PubMed2006

Altered in vitro chondrogenic properties of chondrocytes harvested from unaffected cartilage in osteoarthritic joints.

OBJECTIVE: In vitro models of chondrogenesis often depart from chondrocytes harvested from less-affected areas of osteoarthritic joints. However, there are indications that these chondrocytes are phenotypically different from chondrocytes from healthy joints and thus might differ in their capacity to generate hyaline cartilage. The goal of this study was to compare the chondrogenic capacity of chondrocytes from healthy and OA joints. DESIGN: Chondrocytes isolated from nine healthy and nine OA knee joints were expanded in monolayer for two passages. Chondrocytes from passages 1 and 2 were analyzed for expression of (de)differentiation and hypertrophy markers and were seeded at passage 2 on collagen-coated filters for redifferentiation culture to study cartilage matrix formation. RESULTS: The collagen II/I mRNA ratio, reflecting differentiation, decreased from passage 1 to 2 in both chondrocytes from OA joints and chondrocytes from healthy joints (P<0.05), without a significant difference between the two donor types. At passage 1, levels of the cartilage transcription factors Sox-5, Sox-6 and Sox-9 appeared to be higher in chondrocytes from OA joints (n.s.), but this was not seen at passage 2. However, a clear difference was observed in collagen type X expression, which was high in chondrocytes from OA joints at both passages, while undetectable in chondrocytes from healthy joints (P<0.01). Tissue generated by chondrocytes from healthy joints redifferentiated for 28 days, showed a significantly better morphology, as assessed by histological scoring (P<0.01) and higher proteoglycan content (P<0.05), compared to chondrocytes from OA joints. Matrix turnover parameters, i.e., proteoglycan synthesis and degradation rate, were not significantly affected by donor tissue origin. CONCLUSIONS: These results suggest that clear differences between chondrocytes from healthy and OA joints exist and that these are not completely abolished during the process of de- and redifferentiation. Therefore, in vitro cartilage regeneration models, which use chondrocytes from OA joints, should be interpreted with care.

Aged↗

PubMed2006

Impact of expansion and redifferentiation conditions on chondrogenic capacity of cultured chondrocytes.

Cartilage regeneration based on isolated and culture-expanded chondrocytes is studied in a variety of in vitro models, but with varying morphological quality of tissue synthesized. The goal of the present study was to investigate the extent of the influence of expansion and redifferentiation conditions on final tissue morphology by comparing 2 expansion and redifferentiation methods. Chondrocytes from 9 human donors were expanded in medium without growth factor supplementation (basic expansion condition [BEC]) or in medium with basic fibroblast growth factor (bFGF) supplementation (growth factor supplemented expansion condition [GFSEC]). After expansion, cells were either redifferentiated in pellet culture or seeded on collagen type II-coated filters. Post-expansion mRNA levels of collagen type I and II and Sox-5, -6, and 9, measured by semiquantitative real-time polymerase chain reaction (PCR), suggested that expansion in GFSEC results in increased dedifferentiation compared to BEC. However, after 28 days of redifferentiation culture, morphology of tissue synthesized by GFSEC-expanded chondrocytes scored significantly higher on the Bern scale compared to BEC (6.4 +/- 0.3 points vs. 4.5 +/- 0.3 points in pellet culture and 6.0 +/- 0.4 points vs. 4.5 +/- 0.3 points on collagen-coated filters; p < 0.05). Expansion in GFSEC compared to BEC increased proteoglycan (PG) synthesis rate at day 9 (4.0-fold in pellet culture and 1.9-fold on collagen-coated filters; p < 0.01), PG release (6.7-fold in pellet culture and 3.2-fold on collagen-coated filters; p < 0.001), and final PG content at day 28 (1.6-fold in pellet culture and 1.5-fold on collagen-coated filters; p < 0.05). Redifferentiation on collagen-coated filters compared to pellet culture increased PG synthesis rate at day 9 (5.2-fold in BEC-expanded chondrocytes and 2.6-fold in GFSEC-expanded chondrocytes; p < 0.01), PG release (4.2-fold in BEC-expanded chondrocytes and 3.1-fold in GFSECexpanded chondrocytes; p < 0.01), and final PG content (1.3-fold in BEC-expanded chondrocytes and 1.9- fold in GFSEC-expanded chondrocytes; p < 0.01). Moreover, as visualized via electron microscopy, chondrocytes and organization of extracellular matrix cultured on filters was more similar to those found for hyaline cartilage. In conclusion, chondrocyte expansion in GFSEC and redifferentiation on collagen-coated filters resulted in most optimal chondrogenesis.

Cartilage, Articular↗

PubMed2004

Surgical treatment of traumatic fractures of the thoracic and lumbar spine: a systematic review of the literature on techniques, complications, and outcome.

STUDY DESIGN: A systematic review of the literature, pertaining surgical treatment of traumatic thoracic and lumbar spine fractures, was performed. OBJECTIVES: To provide information on surgical techniques for traumatic spine fracture management, their respective performance and complication rates, based on previously published information. SUMMARY OF BACKGROUND DATA: The treatment of traumatic fractures of the thoracic and lumbar spine remains controversial. There is insufficient evidence in the literature to choose between the various surgical options. In absence of conclusive studies, a systematic review can be an alternative to obtain more convincing information. METHODS: Full-text papers from 1970 until 2001 were included if strict inclusion criteria were met. Five surgical subgroups were recognized: posterior short-segment (PS), posterior long-segment (PL), reports on both posterior short- and long-segment (PSL), anterior (A), and anterior combined with posterior (AP) techniques. Clearly defined and generally accepted parameters were scored and subsequently analyzed. The preoperative injury severity of the surgical groups was compared. The neurologic, radiologic, and functional outcome and complications of all groups were assessed. RESULTS: A total of 132 papers, the majority being retrospective case-series, were included representing 5,748 patients. The preoperative injury severity revealed an inequality between the subgroups. Partial neurologic deficits had the potential to resolve irrespective of treatment choice. None of the five techniques used was able to maintain the corrected kyphosis angle. The functional outcome after surgery seems to be better than generally believed. Complications are relatively rare. CONCLUSIONS: In general, surgical treatment of traumatic spine fractures is safe and effective. Surgical techniques can only be compared using randomized controlled trials.

Adult↗

PubMed2004

Design and fabrication of standardized hydroxyapatite scaffolds with a defined macro-architecture by rapid prototyping for bone-tissue-engineering research.

This investigation describes the production and characterization of calcium phosphate scaffolds with defined and reproducible porous macro-architectures and their preliminary in vitro and in vivo bone-tissue-engineered response. Fugitive wax molds were designed and produced using a rapid prototyping technique. An aqueous hydroxyapatite slurry was cast in these molds. After sintering at 1250 degrees C and then cleaning, dimensional and material characterizations of the scaffolds were performed. The resulting scaffolds represented the design, and their dimensions were remarkably consistent. A texture inherent to the layer-by-layer production of the mold was impressed onto the vertical surfaces of the scaffolds. The surface roughness (R(a)) of the textured surfaces was significantly greater than that of the nontextured surfaces. Material analyses revealed a beta-TCP phase in addition to hydroxyapatite for the molded ceramics. Non-molded control ceramics exhibited only hydroxyapatite. Thirty scaffolds were seeded with culture-expanded goat bone-marrow stromal cells (BMSCs) and implanted subcutaneously in nude mice for 4 or 6 weeks. Histology revealed mineralized bone formation in all the scaffolds for both implantation periods. After 4 weeks, bone was present primarily as a layer on scaffold surfaces. After 6 weeks, the surface bone formation was accompanied by bone budding from the surface and occasional bridging of pores. This budding and bridging bone formation almost always was associated with textured scaffold surfaces. However, the area percentage of bone in pores was similar for the 4- and 6-week implantation periods.

Animals↗

PubMed2004

Genetic marking with the DeltaLNGFR-gene for tracing goat cells in bone tissue engineering.

The use of bone marrow derived stromal cells (BMSC's) for bone tissue engineering has gained much attention as an alternative for autologous bone grafting. Little is known however, about the survival and differentiation of the cells, especially in the clinical application. The aim of this study was to develop a method to trace goat BMSC's in vivo. We investigated retroviral genetic marking, which allows stable expression of the label with cell division. Goat BMSC's were subjected to an amphotropic envelope containing a MoMuLV-based vector expressing the human low affinity nerve growth factor receptor (DeltaLNGFR). Labeling efficiency and effect on the cells were analyzed. Furthermore, transduced cells were seeded onto porous ceramic scaffolds, implanted subcutaneously in nude mice and examined after successive implantation periods. Flow cytometry indicated a transduction efficiency of 40-60%. Immunohistochemistry showed survival and subsequent bone formation of the gene-marked cells in vivo. Besides, marked cells were also found in cartilage and fibrous tissue. These findings indicate the maintenance of the precursor phenotype following gene transfer as well as the ability of the gene to be expressed following differentiation. We conclude that retroviral gene marking with DeltaLNGFR is applicable to trace goat BMSC's in bone tissue engineering research.

Animals↗

PubMed2004

Bone tissue engineering and spinal fusion: the potential of hybrid constructs by combining osteoprogenitor cells and scaffolds.

In this paper, we discuss the current knowledge and achievements on bone tissue engineering with regard to spinal fusion and highlight the technique that employs hybrid constructs of porous scaffolds with bone marrow stromal cells. These hybrid constructs potentially function in a way comparable to the present golden standard, the autologous bone graft, which comprises besides many other factors, a construct of an optimal biological scaffold with osteoprogenitor cells. However, little is known about the role of the cells in autologous grafts, and especially survival of these cells is questionable. Therefore, more research will be needed to establish a level of functioning of hybrid constructs to equal the autologous bone graft. Spinal fusion models are relevant because of the increasing demand for graft material related to this procedure. Furthermore, they offer a very challenging environment to further investigate the technique. Anterior and posterolateral animal models of spinal fusion are discussed together with recommendations on design and assessment of outcome parameters.

Animals↗

PubMed2004

Patient-reported outcome in total hip replacement. A comparison of five instruments of health status.

Our aim was to define the minimum set of patient-reported outcome measures which are required to assess health status after total hip replacement (THR). In 114 patients, we compared the pre-operative characteristics and sensitivity to change of the Oxford hip score (OHS), the Western Ontario and McMaster Universities osteoarthritis index (WOMAC), the SF-36, the SF-12 (derived from the SF-36), and the Euroqol questionnaire (EQ-5D). At one year after operation, very large effect sizes were found for the disease-specific measures, the physical domains of the SF-12, SF-36 and the EQ-5Dindex (1.3 to 3.0). Patients in Charnley class A showed more change in the OHS, WOMAC pain and function, the physical domains of the SF-36 and the EQ-5Dvas (p < 0.05) compared with those in the Charnley B and C group. In this group, the effect size for the OHS more than doubled the effect sizes of WOMAC pain and physical function. We found high correlations and correlations of change between the OHS, the WOMAC, the physical domains of the SF-12 and the SF-36 and EQ-5Dindex. The SF-36 and EQ-5D scores at one year after operation approached those of the general population. Furthermore, we found a binomial distribution of the pre-operative EQ-5Dindex score and a pre-operative discrepancy and post-operative agreement between the EQ-5Dvas and EQ-5Dindex. We recommend the use of the OHS and SF-12 in the assessment of THR. The SF-36 may be used in circumstances when smaller changes in health status are investigated, for example in the follow-up of THR. The EQ-5D is useful in situations in which utility values are needed in order to calculate cost-effectiveness or quality-adjusted life years (QALYs), such as in the assessment of new techniques in THR.

Aged↗

PubMed2004

Histologic changes after vertebroplasty.

BACKGROUND: Vertebroplasty with use of polymethylmethacrylate cement is gaining popularity in the treatment of some specific painful lesions of the spine. It remains unclear, however, what possible side effects this type of cement might have upon the vertebral body. We performed a histologic and radiographic analysis of the end plate and disc to determine whether there was a difference between vertebroplasty with polymethylmethacrylate cement and vertebroplasty with calcium phosphate cement in the surrounding tissue of the goat spine. Furthermore, we assessed whether a defect in the end plate, simulating end-plate fracture and allowing for direct contact of cement with disc tissue, had any effect on end-plate or disc degeneration. METHODS: Twenty-four mature goats were divided between two follow-up periods (six weeks and six months). All animals underwent a bilateral transpedicular vertebroplasty at two lumbar levels, where one of the following treatments was applied: vertebroplasty with calcium phosphate cement with or without an end-plate defect, and vertebroplasty with polymethylmethacrylate cement with or without an end-plate defect. The effect of the various treatments on the integrity of the intervertebral disc, end plate, and surrounding tissue was examined with semiquantitative histologic analysis and radiography. RESULTS: No sign of disc or end-plate degeneration was seen in any of the analyzed sections. The mean disc height did not decrease from the postoperative period to the time that the animals were killed in any group, thereby supporting the histologic findings. A mild inflammatory reaction was found in four vertebral bodies in the polymethylmethacrylate groups only. CONCLUSIONS: Calcium phosphate cement and polymethylmethacrylate cement both seem to be adequate bone-void fillers in terms of biological behavior in the vertebral body.

Animals↗

PubMed2003

The interaction between Sillence type and BMD in osteogenesis imperfecta.

Clinical studies with bisphosphonates in children with osteogenesis imperfecta (OI) show an increase in BMD and a decrease in fracture rate. Bone strength in children with OI is not only influenced by changes in BMD but also by changes in collagen I structure of the organic bone matrix. Therefore, we studied the interaction between these two factors in a cross-sectional, single center study including 54 children. We assumed that vertebral deformities in OI represent an unbalance between load and bone strength. Body weight was considered to be a well quantifiable load on vertebral bodies. BMD served as a marker, representing the amount of bone tissue available for vertebral load bearing, and the Sillence classification, either type I or III/IV, as a marker representing the quality of the organic bone matrix. Independent associations were observed between the prevalence of vertebral deformities and (1) Sillence type (OR: 5.7, 95%Cl:1.2-26.8), (2) BMD (OR: 0.003, 95%Cl: 0-0.25) and (3) body weight (OR: 1.15, 95%Cl: 1.05-1.25). Regarding the anthropometrical differences among the different types of OI, the BMD/body weight ratio was introduced to evaluate the BMD in relation to body size. Prevalent vertebral deformities were associated with low BMD/body weight ratios (OR: 0.04, 95%Cl: 0.008-0.2) in OI type I, but no association was found in type III/IV. It was concluded that BMD and Sillence type have independent relationships with vertebral deformities. The BMD/body weight ratio correlates with vertebral deformities in children with OI type I. Its meaning in types III/IV needs further research with larger samples because of the relatively high prevalence of vertebral deformities in this group.

Absorptiometry, Photon↗

PubMed2003

Application and limitations of chloromethyl-benzamidodialkylcarbocyanine for tracing cells used in bone Tissue engineering.

Bone tissue engineering has the potential to provide us with an autologous bone substitute. Despite extensive research to optimize the technique, little is known about the survival and function of the cells after implantation. To monitor the cells, in vivo labeling is the method of choice. In this study we investigated the use of the fluorescent membrane marker chloromethyl-benzamidodialkylcarbocyanine (CM-Dil) to label cells used in bone tissue engineering. When applying label concentrations up to 50 microM, cells could be labeled efficiently without negative effects on cell vitality, proliferation, or bone-forming capacity. Porous hydroxyapatite scaffolds were seeded with labeled cells, and up to 6 weeks after implantation in nude mice cells could be traced inside tissue-engineered bone. However, contrary to other reports concerning intramembranous labels, transfer of the label from labeled to unlabeled cells was detected. Transfer occurred both in vitro and in vivo between vital cells and between dead and living cells. To determine when in vivo label transfer happened, devitalized, labeled constructs were implanted for various time periods in nude mice. The presence of vital labeled cells inside these constructs, when evaluated at different implantation periods, indicated transfer of the label. Transfer occurred at 7 days postimplantation when 40 microM label was applied, whereas 10 microM labeled constructs showed transfer 10 days after implantation. These findings indicate that CM-Dil label is useful for in vivo tracing of cells for follow-up periods up to 10 days. This makes the label particularly useful for cell survival studies in tissue-engineered implants.

Bone and Bones↗

PubMed2003

Viable osteogenic cells are obligatory for tissue-engineered ectopic bone formation in goats.

In this study we investigated the bone-forming capacity of tissue-engineered (TE) constructs implanted ectopically in goats. As cell survival is questionable in large animal models, we investigated the significance of vitality, and thus whether living cells instead of only the potentially osteoinductive extracellular matrix are required to achieve bone formation. Vital TE constructs of porous hydroxyapatite (HA) covered with differentiated bone marrow stromal cells (BMSCs) within an extracellular matrix (ECM) were compared with identical constructs that were devitalized before implantation. The devitalized implants did contain the potentially osteoinductive ECM. Furthermore, we evaluated HA impregnated with fresh bone marrow and HA only. Two different types of HA granules with a volume of approximately 40 microm were investigated: HA70/800, a microporous HA with 70% interconnected macroporosity and an average pore size of 800 microm, and HA60/400, a smooth HA with 60% interconnected macropores and an average size of 400 microm. Two granules of each type were combined and then treated as a single unit for cell seeding, implantation, and histology. The tissue-engineered samples were obtained by seeding culture-expanded goat BMSCs on the HA and subsequently culturing these constructs for 6 days to allow cell differentiation and ECM formation. To devitalize, TE constructs were frozen in liquid nitrogen according to a validated protocol. Fresh bone marrow impregnation was performed perioperatively (4 mL per implant unit). All study groups were implanted in bilateral paraspinal muscles. Fluorochromes were administered at three time points to monitor bone mineralization. After 12 weeks the units were explanted and analyzed by histology of nondecalcified sections. Bone formation was present in all vital tissue-engineered implants. None of the other groups showed any bone formation. Histomorphometry indicated that microporous HA70/800 yielded more bone than did HA60/400. Within the newly formed bone, the fluorescent labels showed that mineralization had occurred before 5 weeks of implantation and was directed from the HA surface toward the center of the pores. In conclusion, tissue-engineered bone formation in goats can be achieved only with viable constructs of an appropriate scaffold and sufficient BMSCs.

Animals↗

PubMed2003

Joint homeostasis. The discrepancy between old and fresh defects in cartilage repair.

The discrepancy between successful experimental studies of cartilage repair and the clinical results is unexplained. We have evaluated the effect of metabolic alterations in joint homeostasis owing to an articular defect on the outcome of cartilage repair using tissue engineering methods. We used 21 adolescent Dutch goats divided into three groups. The control knees were left untreated while the contralateral knee was randomised to receive either no treatment (N), early treatment (E) or late treatment (L). The metabolism of proteoglycans in the surrounding joint surface was determined and correlated with the O'Driscoll score used to quantify the histological aspect of the repair of the defect. Synthesis of proteoglycan (PG) was increased in all groups. The release of glucosaminoglycan (GAG) was significantly higher in the untreated but not after early transplantation (1.3 v 1.8 NS). The cartilage repair scores in the early treatment group were not as good as those of the normal control group, but were significantly better when compared with both the untreated defects and the late treated defects. Defects which had been treated late showed a significantly decreased score when compared with those which had had early treatment or the normal control group and did not differ (p = 0.12) from those with no treatment. The histological and biochemical scores closely resembled the macroscopic and functional parameters which showed a significant deterioration for the late treated group and those without treatment compared with animals treated early. Thus, tissue-engineered cartilage repair is negatively influenced by altered matrix metabolism. Early treatment showed significantly better results for repair of cartilage than late or no treatment, with a concurrent decrease in the detrimental disturbance of cartilage metabolism which constituted a protective effect on the articulation.

Animals↗

PubMed2002

[The disc prosthesis: myths and facts].

The results of surgical treatment of degenerative low-back conditions by means of a fusion (spondylodesis) are in general less predictable than operative treatments for arthrosis of the (large) peripheral joints. Recently, new techniques of disc replacement have been developed as an alternative to traditional fusion operations. The most important theoretical advantage is the prevention of adjacent segment degeneration in the longer term. Because the disc prosthesis replaces the presumably painful intervertebral disc--just as an intercorporal fusion--the short-term results are expected to be comparable to ventral fusion. The results with a short follow-up period described in the literature are comparable to those published for spondylodesis. However, disc prosthesis requires a more extensive approach and therefore more serious complications are to be expected. In the longer term, prosthesis-related complications can be expected because these prostheses are used in young and active patients. Despite 15 years of small-scale experience in some European countries, there is a lack of reliable information about the middle and long-term performance of these prostheses in the peer-reviewed literature. Therefore, these implantations should be regarded as experimental procedures and should be confined to clinical trials in centres with sufficient experience in the operative treatment of degenerative low-back conditions as well as the necessary infrastructure to follow up these usually young patients in a scientifically responsible manner over a period of decades. These centres should also have the expertise necessary to adequately deal with the possible complications.

Humans↗

PubMed2002

Severe erosion of lumbar vertebral body because of abdominal aortic false aneurysm: report of two cases.

STUDY DESIGN: Two cases of lumbar vertebral erosion resulting from abdominal aortic false aneurysm are reported. OBJECTIVE: To present an uncommon complication of aortic endoprosthesis causing spinal pathology. SUMMARY OF BACKGROUND DATA: Vertebral body pathologies usually are associated with fracture, osteoporotic collapse, tumor, spondylitis, or spondylodiscitis. Aortic abdominal aneurysm rarely has been reported as causing lytic lesions of the spine. METHODS: A retrospective case analysis was performed for two patients with an aorta bifurcation prosthesis and lytic lesions of the spine. False aneurysms were detected at the proximal junction of the prostheses. A biopsy of the affected vertebrae showed no infection or malignancy. Surgery was performed in both cases, and the prostheses were successfully revised. In one case, an anteroposterior spinal fusion was performed because of severe anterior bone loss. RESULTS: The back pain of both patients resolved completely after surgery. In one of the patients, an embolectomy in the right leg failed, and a below-the-knee amputation had to be performed. CONCLUSIONS: In patients with endovascular prostheses, false aneurysm should be considered when lytic lesions of vertebral bodies are differentially diagnosed because these patients can present with only spinal symptoms.

Aged↗

PubMed2002

Osseointegration of hydroxyapatite-coated and noncoated Ti6Al4V implants in the presence of local infection: a comparative histomorphometrical study in rabbits.

A study was designed to investigate the osseointegration of titanium implants, either noncoated or coated with hydroxyapatite (HA), into rabbit tibiae in the presence of local infection compared with osseointegration in the absence of local infection. HA-coated or noncoated Ti cylinders were implanted into both tibiae of 32 rabbits (New Zealand Whites). Before implantation the left tibia was contaminated with different quantities of Staphylococcus aureus (10(2)-10(5) CFU). Four weeks after surgery the tibiae were explanted and prepared for microbiological and histomorphometrical examination. Histomorphometrical data, as a representation of implant fixation, were obtained by measuring the percentage of bone around the implants (within a radius of 1 mm from the outer diameter of the implants) and the percentage of the circumference of the implant that was in direct contact with bone. Histomorphometry revealed, in particular for the HA implants, a relationship between the inoculum concentration and/or the presence or absence of infection with the bone contact at the distal implant side. This confirms a relationship between peri-implant infection and bone contact or remodeling. HA-coated implants developed, in the presence of bacteria, more easily a more severe infection than noncoated Ti implants, and we show in the present study that local infection will influence histomorphometrical parameters (bone-implant contact) that determine implant fixation. Precautions to prevent contamination (asepsis) and/or infection (perioperative antibiotics) are even more important for the highly biocompatible HA-coated implant.

Alloys↗

PubMed2002

Some complications of common treatment schemes of thoracolumbar spine fractures can be predicted with magnetic resonance imaging: prospective study of 53 patients with 71 fractures.

STUDY DESIGN: Prospective cohort study. OBJECTIVES: To study the predictive value of magnetic resonance imaging (MRI) findings of thoracolumbar spine fractures concerning the radiologic and clinical outcome. SUMMARY OF BACKGROUND DATA: Disagreement about the proper treatment of thoracolumbar spine fractures is caused by insufficiency of conventional imaging techniques. Previous studies have shown that MRI is capable of distinguishing injury to all structures of the fractured spine and thus may help develop schemes with higher predictive power. METHODS: A total of 53 patients with 71 fractures were studied with MRI in a prospective fashion. A total of 24 patients with 39 fractures were treated conservatively and 29 patients with 32 fractures were treated operatively after a protocol concerning the treatment options. MRI scans were obtained within 1 week of injury and at the 2-year follow-up. Pain scores were obtained at the 2-year follow-up. Previously described MRI schemes concerning the trauma and post-trauma conditions were used. RESULTS AND CONCLUSIONS: An unfavorable outcome in the conservative group was related to the progression of kyphosis, which in most cases was predictable with the use of trauma MRI findings concerning the endplate comminution and vertebral body involvement. In the operatively treated group, recurrence of the kyphotic deformity was predictable by the lesion of the posterior longitudinal ligamentary complex together with endplate comminution and vertebral body involvement as seen on trauma MRI. The authors recommend the use of MRI to develop reliable prognostic criteria for these injuries.

Adolescent↗

PubMed2002

Balloon vertebroplasty with calcium phosphate cement augmentation for direct restoration of traumatic thoracolumbar vertebral fractures.

STUDY DESIGN: A human cadaveric model was used to evaluate balloon vertebroplasty in traumatic vertebral fractures. OBJECTIVES: To assess the feasibility and safety of balloon vertebroplasty followed by calcium phosphate cement augmentation to prevent recurrent kyphosis. SUMMARY OF BACKGROUND DATA: Failure after short-segment pedicle-screw fixation for the treatment of vertebral fractures is probably caused by a redistribution of disc material through the fractured endplate into the vertebral body, causing a decrease in anterior column support. This lack of support can give rise to instrument breakage and recurrent kyphosis after removal of the instrumentation. Restoration of the endplate morphology could prevent these events. METHODS: Twenty-three traumatic fractures of thoracolumbar vertebrae were created. All fractures were distracted and fixated with short-segment pedicle screws and rods. Transpedicularly introduced inflatable bone tamps and subsequent injection of calcium phosphate cement were used to restore the endplates. Quantitative analyses of magnetic resonance images obtained at three time points were used to evaluate the morphology of the vertebral body and disc-space. After slicing all specimens, macroscopical examination was performed to detect leakage of cement or bone displacement in undesired directions. RESULTS: No technical problems were encountered during the study. The balloon vertebroplasty resulted in a significant (P = 0.0014) decrease of cranial endplate impression. No cement leakage or undesired bone displacement could be detected radiologically or macroscopically. CONCLUSIONS: The present study suggests that balloon vertebroplasty may be a safe and feasible procedure for the restoration of traumatic thoracolumbar vertebral fractures.

Aged↗

PubMed2002

Classification of thoracic and lumbar spine fractures: problems of reproducibility. A study of 53 patients using CT and MRI.

Reproducibility of fracture classification systems in general has been a matter of controversy. The reproducibility of spinal fracture classifications has not been sufficiently studied. We studied the inter-observer and intra-observer reproducibility of the Magerl (AO) classification using radiograms, CTs and MRIs of 53 patients. We compared this classification with the older and simpler Denis classification. Five observers classified the fractures, first using the radiograms and CTs and, 6 weeks later, with radiograms and MRIs. Three of the observers repeated the readings after 3 months. Three observers also classified the fractures according to Denis. Agreement was measured using Cohen's kappa test. The type (A, B, C) classification of the AO system was fairly reproducible with CTs. With MRI this was only moderate. Group subclassification of the types yielded higher kappa values, corresponding to substantial agreement. The agreement was, in general, better with the Denis classification, but the variance was higher due to the difficulty of finding proper categories for some injury patterns. Although the AO classification allows proper registration of all kinds of injury, the reproducibility, especially at the type level, is problematic. Use of MRI and better definition of the distinctive properties of the three different types may enhance the reproducibility of the scheme.

Diagnosis, Differential↗