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A J Verbout

Publications and source records attributed to A J Verbout.

At least 37 records · Page 2Linked to original sources
PubMed2002

Evaluating 3D bone tissue engineered constructs with different seeding densities using the alamarBlue assay and the effect on in vivo bone formation.

Bone tissue engineering using patient derived cells seeded onto porous scaffolds has gained much attention in recent years. Evaluating the viability of these 3D constructs is an essential step in optimizing the process. The alamarBlue (aB) assay was evaluated for its potential to follow in vitro cell proliferation on architecturally standardized hydroxyapatite scaffolds. The impact of the aB assayed and seeding density on subsequent in vivo bone formation was investigated. Twelve scaffolds were seeded with various densities from 250 to 2.5x10(6) cells/scaffold and assay by aB at 5 time points during the 7-day culture period. Twelve additional scaffolds were seeded with 2.5x10(5) cells/scaffold. Two control and 2 aB treated scaffolds were subcutaneously implanted into each of 6 nude mice for 6 weeks. Four observers ranked bone formation using a pair wise comparison of histological sections form each mouse. The aB assay successfully followed cell proliferation, however, the diffusion kinetics of the 3D constructs must be considered. The influence of in vitro aB treatment on subsequent in vivo bone formation cannot be ruled out but was not shown to be significant in the current study. The aB assay appears to be quite promising for evaluating a maximum or end-point viability of 3D tissue engineered constructs. Finally, higher seeding densities resulted in more observed bone formation.

Journal Article↗
PubMed2002

The correlation and reproducibility of histological scoring systems in cartilage repair.

In recent years, the field of cartilage tissue engineering has seen a sharp increase in publications using many tissue engineering techniques and various analysis methods. Comparison between studies remains difficult, due to a lack of uniformity in methods used. A broad range of histological scoring systems is used to examine cartilage quality. Unfortunately, so far little is known on the reliability and correlation of these scoring systems. The objective of this study was to compare two frequently used cartilage repair grading scales, namely, the comprehensive O'Driscoll and the simple Pineda scale. We determined the intra- and interobserver variability of each score as well as the correlation between them. Thirty-eight joint section samples with variable cartilage quality were examined. Three observers documented their findings with both systems at two points in time. Statistical analysis showed very good intra- and interobserver reliability as well as a good correlation between the two scores. For the intraobserver variability of the O'Driscoll scale, we found an average difference of 0.05 with a SD of 0.93 in a 24-point score and a kappavalue of 0.87. For the interobserver reliability, the average difference was 0.001, SD 2.25, and a kappavalue of 0.92. The Pineda scale showed an average difference of 0.86 with a SD of 1.38 in a 14-point score and a kappavalue of 0.86 for the intraobserver reliability, whereas values for the interobserver reliability were average difference 0.82, SD 0.96, and a kappavalue of 0.89. The comparison between the two scales showed a high, inversely related correlation with a correlation coefficient of 0.71. From these results, we concluded that both the O'Driscoll and the Pineda scales are reliable semiquantitative cartilage scoring systems and that acceptance for general use of these two scores will benefit the reliability of literature on tissue engineering for cartilage repair. Thus, the added strength of comparison between published study results allows better understanding of cartilage repair publications and increases the impact of their results.

Animals↗
PubMed2001

Traumatic lumbosacral dislocation: case report.

STUDY DESIGN: A case report of a bilateral lumbosacral dislocation without a fracture is presented. OBJECTIVE: To report the diagnosis and treatment of a traumatic lumbosacral dislocation. SUMMARY OF BACKGROUND DATA: Lumbosacral dislocations without fractures are rare injuries, with only four cases reported in literature. The recommended treatment consists of an anterior lumbar interbody fusion after posterior reduction with pedicle screw instrumentation. METHODS: The 1-year follow-up evaluation of a 17-year-old male with a traumatic lumbosacral dislocation, diagnosed with computed tomography and magnetic resonance imaging, and treated with a posterior lumbar interbody fusion procedure combined with a posterolateral fusion is reported. RESULTS: At 1 year after surgery the patient is asymptomatic and has resumed his heavy manual work. Radiologic evidence of interbody fusion is present. CONCLUSIONS: Lumbosacral dislocations are rare injuries. The authors demonstrate the feasibility of a posterior lumbar interbody fusion procedure in combination with posterolateral instrumentation and fusion.

Accidents, Occupational↗
PubMed2001

Tobramycin-containing bone cement and systemic cefazolin in a one-stage revision. Treatment of infection in a rabbit model.

The efficacy of tobramycin-containing bone cement with that of systemic cefazolin for treatment of infection in a one-stage revision model is compared. In addition, the value of detecting bacterial DNA after antibiotic treatment was investigated. An implant was inserted into the right tibia of rabbits after inoculation with Staphylococcus aureus. At 28 days, the implant was removed. Subsequently, either plain bone cement with or without systemic administration of cefazolin, or tobramycin-containing bone cement was injected into the medullary canal. The tibiae were cultured 14 days after revision (Day 42), and showed a significant decrease in bacterial counts for both antibiotic groups compared with the control group (p</=0.05). The rate of infection in the tobramycin-cement group was slightly higher (2/9) than in the cefazolin group (0/8), although the difference was not significant. Persistence of bacterial DNA after antibiotic treatment may be the result of delayed clearance of DNA and not a sign of active infection. This animal model shows that in a one-stage revision tobramycin-containing bone cement can reduce size and rate of infection, although systemic cefazolin may be more efficacious. Therefore, the use of antibiotic-containing bone cement combined with systemic antibiotic might provide optimal treatment.

Animals↗
PubMed2000

Prevention of infection with tobramycin-containing bone cement or systemic cefazolin in an animal model.

We investigated in an animal model the efficacy of tobramycin-containing bone cement and systemic cefazolin for infection prophylaxis. In 18 female rabbits, the femoral cavity was inoculated with Staphylococcus aureus before injection of bone cement. The first group of six rabbits received tobramycin-containing Simplex-P bone cement. Two other groups of six rabbits received plain Simplex-P bone cement. Preoperatively, in one of the two latter groups cefazolin was administered intravenously. The other group served as untreated controls. The rabbits were monitored for clinical signs of infection. At 7 days' follow-up, the femora were harvested and cultures from the bone adjacent to the cement plug were quantified. Cultures from the rabbits which received antibiotic prophylaxis (either cefazolin systemically or tobramycin-containing bone cement) were all negative. In contrast, all rabbits in the untreated control group had positive cultures. These rabbits also had other signs of infection such as an elevated erythrocyte sedimentation rate and loss of body weight. Culture results were confirmed by the absence of bacterial DNA in the polymerase chain reaction hybridization assay. In conclusion, we found that both tobramycin-containing bone cement and systemic cefazolin are effective in preventing implant bed infection in rabbits up to 7 days after contamination with S. aureus.

Animals↗
PubMed2000

Prophylaxis of implant-related staphylococcal infections using tobramycin-containing bone cement.

In a rabbit model, premixed tobramycin-containing bone cement was studied for its efficacy to prevent infections with two frequently encountered staphylococcal species in arthroplasty surgery. After intramedullary inoculation with staphylococci, either standard or premixed tobramycin-containing Simplex-P bone cement was injected in the right femur of 120 rabbits. Development of infection was examined by culture of femoral bone after 7 or 28 days. Loss of body weight and elevated erythrocyte sedimentation rate in the control rabbits inoculated with Staphylococcus aureus were seen in the first postoperative week, returning to normal in 28 days. Inoculation with Staphylococcus epidermidis resulted only in a low-grade infection. All rabbits receiving premixed tobramycin-containing bone cement were free of signs of infection, and all their cultures were negative. Culture yield from Staphylococcus aureus controls increased with time and inoculum dose. Staphylococcus epidermidis controls needed higher inoculum doses to establish an infection, while culture yield decreased in time. These differences in mode of prosthesis-related infection are explained by differences in virulence factors.

Animals↗
PubMed2000

Effects of hydrosyapatite coating on Ti-6A1-4V implant-site infection in a rabbit tibial model.

To investigate the effect of implant type after direct contamination, a hydroxyapatite-coated or noncoated Ti-6A1-4V implant was inserted into both tibiae of 32 New Zealand White rabbits. Prior to implantation, the left tibia was contaminated with increasing concentrations of Staphylococcus aureus (10(2)-10(5) colony-forming units), ranging from very low (10(2)) to relatively high (10(5)). Four weeks after implantation, half of the tibial bone adjacent to the implant was harvested for bacteriological examination. Bacterial counts were quantified by plating serial dilutions. For the histological evaluation, sections of the implant with the remaining tibia were examined by semiquantitative scoring of infection parameters. The bacteriological data showed the inoculum dose and implant type to have a significant effect on the culture outcome: more bacteria were retrieved from the hydroxyapatite-coated implants than from the noncoated titanium implants. Histological evaluation showed an increased score for the infected left tibiae compared with their contralateral control. In addition, with increasing inoculum dosage, the difference between the two types of implant increased. We demonstrated that infections can occur with biocompatible, noncemented implants and that they are related to the dose of the original inoculum. Bacteria were more likely to grow onto or next to the hydroxyapatite implants than on titanium implants and resulted in a more severe histopathological characterization of infection.

Aluminum↗
PubMed2000

Joint distraction in treatment of osteoarthritis (II): effects on cartilage in a canine model.

OBJECTIVE: From a clinical point of view, joint distraction as a treatment for osteoarthritis (OA) of hip and ankle has been demonstrated to be very promising. Pain, joint mobility and functional ability, the most important factors for a patient with severe OA, all improved. Although radiographic joint space enlargement in a significant number of patients suggested cartilage repair, actual cartilage repair remains difficult to evaluate. Therefore the present study was initiated to evaluate the actual effects of joint distraction on cartilage. METHODS: For this purpose a canine model for OA, anterior cruciate ligament transection (ACLT) was used. Sixteen weeks after ACLT articulating Ilizarov joint distraction of the knee was carried out. Absence of mechanical contact between articular surfaces and presence of intra-articular intermittent fluid pressure, characteristics of Ilizarov joint distraction, were confirmed. Twenty-five weeks after ACLT joint tissue of the dogs was analyzed. RESULTS: Biochemical analysis showed that after joint distraction the abnormal cartilage proteoglycan (PG) metabolism, characteristic for OA, had changed to a level found in control joints. Moreover, a mild degree of inflammation, present after ACLT, was reduced upon joint distraction. PG-content and histological cartilage degeneration had not (yet) improved within the time of treatment. DISCUSSION: Results suggest that the promising clinical results of Ilizarov joint distraction in patients with OA are accompanied by changes in cartilage metabolism. A change in proteoglycan turnover, indicating normalization of overall chondrocyte function, might in the long term, with normal joint use, lead to actual repair of cartilage.

Animals↗
PubMed2000

Collagen structure regulates fibril mineralization in osteogenesis as revealed by cross-link patterns in calcifying callus.

Although >80% of the mineral in mammalian bone is present in the collagen fibrils, limited information is available about factors that determine a proper deposition of mineral. This study investigates whether a specific collagen matrix is required for fibril mineralization. Calcifying callus from dog tibias was obtained at various times (3-21 weeks) after fracturing. At 3 weeks, hydroxylysine (Hyl) levels were almost twice as high as in control bone, gradually reaching normal levels at 21 weeks. The decrease in Hyl levels can only be the result of the formation of a new collagen network at the expense of the old one. The sum of the cross-links hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP) in callus matched that of bone at all stages of maturation. However, the ratio HP/LP was 2.5-4.5 times higher in callus at 3-7 weeks than in normal bone and was normalized at 21 weeks. Some 40% of the collagen was nonmineralized at the early stages of healing, reaching control bone values (approximately 10%) at 21 weeks. In contrast, only a small increase in callus mineral content from 20.0 to 22.6 (% of dry tissue weight) from week 3 to 21 was seen, indicating that initially a large proportion of the mineral was deposited between, and not within, the fibrils. A strong relationship (r = 0.80) was found between the ratio HP/LP and fibril mineralization; the lower the HP/LP ratio, the more mineralized the fibrils were. Because the HP/LP ratio is believed to be the result of a specific packing of intrafibrillar collagen molecules, this study implies that mineralization of fibrils is facilitated by a specific orientation of collagen molecules in the fibrils.

Amino Acids↗
PubMed1999

MRI findings of thoracolumbar spine fractures: a categorisation based on MRI examinations of 100 fractures.

OBJECTIVE: To define the state of different structures of the fractured thoracolumbar spine which may play a role in the immediate and long-term mechanical stability on MR images and to investigate the relationship of these findings with the AO classification of spinal injuries. DESIGN: The state of the anterior longitudinal ligament, posterior longitudinal ligament, posterior ligamentous complex, cranial and caudal endplates, cranial and caudal discs and the vertebral body were defined using clinical, experimental and radiological data. The state of these structures was reported for each fracture on the MRI examinations and the different MRI features appropriate for different fracture classes were defined. PATIENTS: MRI examinations of 70 patients with 100 fractures of the thoracolumbar spine were used for this study. RESULTS: Wide variations were seen in the state of the structures studied. We could not find a definite pattern to relate these findings with the AO classification scheme. CONCLUSIONS: MR findings should be integrated into future classification schemes of thoracolumbar spine fractures. This would enable specific data about the structures involved in the stability of the spine to be acquired. Prospective studies using the criteria developed in this study may help resolve some of the controversies concerning the diagnosis and prognosis of these injuries as well as the development of new classification systems.

Humans↗
PubMed1999

Correlation of MR images of disc injuries with anatomic sections in experimental thoracolumbar spine fractures.

This cadaver study evaluated the value of MR images for detection of acute intervertebral disc damage associated with fractures of the thoracolumbar spine. Damage to the intervertebral disc may be a major contributor to chronic instability in non-operative treatment or failure of fixation and recurrence of deformity in posterior fixation methods. MR imaging can help us to understand the injury patterns and their prognostic significance. However, before we can justify the use of MRI in clinical cases, determination of MRI's ability to detect acute injury to the disc is necessary. Ten fresh cadaver specimens were used for this study. After obtaining radiograms and MR images, injuries were created with a weight-dropping apparatus using a variety of weights and compression angles. Post-injury radiograms and MR images were taken and the specimens were frozen at -20 degrees C. Slides of these specimens obtained with cryosection techniques were compared with MR images for evaluation of the damage to different parts of the discs. A total of 20 fractures were observed on cryosections. In 12 of the discs adjacent to fractured vertebral bodies, macroscopic damage was seen on the sections. These were all detected on the corresponding MR images. The study showed that MRI is able to detect acute, macroscopic injury to the intervertebral disc. It is therefore justified to use MR for the study of acute disc damage associated with thoracolumbar fractures.

Aged↗
PubMed1999

Joint distraction in treatment of osteoarthritis: a two-year follow-up of the ankle.

OBJECTIVE: Osteoarthritis (OA) is a degenerative joint disease with an incidence exceeding 10% of the adult population. In end stages, OA can result in severe restriction of activity and consequent disability. For these severe cases of OA, no effective remedy is available yet. Joint distraction is a new experimental approach in treatment of OA. Studied in retrospect it appeared that this treatment results in prolonged clinical improvement in the case of ankle OA. Presently the results of a prospective two-year follow-up are given. METHODS: Patients with severe ankle OA, who were considered for joint fusion (arthrodesis), were treated with distraction, by use of an Ilizarov external ring fixator. Distraction was carried out for 3 months during which full weight bearing (walking) was allowed. Standardized clinical examination was conducted before and at yearly intervals after treatment, including physical examination, functional ability questionnaire, pain scale, joint mobility, and radiographic evaluation. RESULTS: More than two thirds of the patients improved significantly as shown by physical examination, functional ability questionnaires and pain scale; effects were progressive in the second year of follow-up. On average, joint mobility and radiographic joint space were preserved, whilst improvement was observed in a significant number of patients. DISCUSSION: Results of the present prospective study confirm the findings of the previous retrospective study and suggest that Ilizarov joint distraction is a promising treatment for severe ankle OA, at least delaying the need for a joint fusion. Considering the high prevalence of OA and the lack of a remedy for this disorder, Ilizarov joint distraction as a treatment for OA may have great medical, social and economic impact.

Adolescent↗
PubMed1999

Critical size defect in the goat's os ilium. A model to evaluate bone grafts and substitutes.

Bone defects and their treatment are a well known problem in orthopaedic surgery. A critical size defect is a suitable model to study bone replacement materials. This study describes a critical size defect in the goal and the evaluation of three bone fillers (particulate autograft, particulate allograft, and a polyethylene oxide/polybutylene terephthalate copolymer) in this defect. The goat allows for implantation of large implants and has a metabolic rate more comparable with that of humans than small animals. The critical size defect, located in the goat's iliac wing, is easily reproducible and allows qualitative and quantitative evaluation of bone grafts and bone graft substitutes. After 3 months of healing, the unfilled defects showed 13.5% bone in the defect, the autografted defects 36.3%, and the allografted 18.5%. The copolymer gave only 1.5% bone in the defect; this is in contrast to previous reports. The described model allows for the evaluation of bone graft substitutes before introduction into clinical practice.

Animals↗
PubMed1998

Integration of press-fit implants in cortical bone: a study on interface kinetics.

The early healing phase of hard tissue implants is important to their long-term success. Problems during this phase can result in a so-called primary biological failure. In 24 New Zealand white rabbits, the healing in cortical bone of noncoated TiAlV and cpTi cylinders and of TiAlV cylinders plasma-spray-coated with hydroxyapatite (HA) of fluorapatite (FA) was investigated histologically and histomorphometrically after 3, 7, 14, and 28 days. Histomorphometry consisted of bone contact measurements and the use of a new semi quantitative scoring system that discriminated various tissues in contact with the implant. The results demonstrated that the most important parameter in initial implant healing is the bone itself and not the characteristics of the implanted material. For all implants, healing was characterized by a sequence of hematoma formation, bone resorption, and new bone formation where the initial press-fit situation revealed more bone-implant contact than after 7 and 14 days. There were only minor differences between the implant types: the new bone formation directly on the implant surface was qualitatively histologically superior to the CaP-coated implants, but this could be confirmed with the scoring method only for the HA-coated implants. It is concluded that initial press-fit fixation in cortical bones is not an end situation; rather, what happens is that as a result of interface remodeling, early postoperatively implant integration in the bone will decrease temporarily prior to a subsequent phase of new bone formation.

Animals↗
PubMed1998

[Total hip replacement arthroplasty in the Netherlands].

The total hip arthroplasty (THA) is an effective treatment of osteoarthritis of the hip joint. Each year, more than 16,000 THAs are performed in the Netherlands. The incidence of THA had doubled between 1980 and 1994. The medical indication has extended to younger and older patients. Due to the success of the THA the number of alternative treatments, such as arthrodesis and osteotomy decreased. The number of revision surgeries increased more than four folds, to 1,400 in 1994. Based on these data the increase of primary and revision hip arthroplasties is expected to continue, but it is unknown how much the exact increase will be. In view of the increased demand it is important to gain more insight into the numbers of primary and revision surgical procedures to be expected, so that a better estimation can be made of the health care capacity and financial resources required in the future.

Adolescent↗
PubMed1998

[An estimate of the intramural costs of the placement of a total hip prosthesis].

OBJECTIVE: Determining the intramural costs of the (re) placement of a total hip prostheses. DESIGN: Retrospective, descriptive. SETTING: Utrecht University Hospital (AZU) and the De Weezenlanden Hospital in Zwolle (ZWZ), the Netherlands. PATIENTS AND METHOD: From the records of 137 patients in whom an uncomplicated primary placement or revision of 151 total hip prostheses had taken place in the AZU or the ZWZ during the period 1990-93, data were collected on the number of days hospitalised, the length of the operation, the medical materials used, the number of radiological procedures, ECG's and laboratory determinations, and the visits to the outpatient clinic. The costs of a hip replacement were determined on the basis of the salary costs, tariffs and purchase prices. RESULTS: The average total cost was f 9381 for the placement of a cemented prosthesis, f 10,796 for the placement of a cement-free prosthesis, and f 17,879 for a revision operation. About 90% of the total costs were due to the price of hospitalization, surgery and prosthesis. With 14,000 primary placements and 1400 revisions annually, the cost is approximately 186 million guilders. An expected increase in the number of hip replacements and their cost should be taken into consideration.

Arthroplasty, Replacement, Hip↗
PubMed1998

The prevention of peridural adhesions. A comparative long-term histomorphometric study using a biodegradable barrier and a fat graft.

We studied peridural fibrosis in 16 dogs after laminectomies at the L2, L4 and L6 levels. They received either a free fat graft, a biodegradable mechanical barrier (polyethylene oxide (PEO)/polybutylene terephthalate (PBT) copolymer), or no treatment. The animals were killed after 4, 12, 26 and 52 weeks. Histomorphometry showed extensive and consistent peridural fibrosis in control and PEO/PBT groups. Fat grafts produced significantly less fibrous tissue, but the presence of the fat graft in the bony defect prevented closure. Degradation of the PEO/PBT barrier resulted in the formation of more fibrous tissue. We conclude that up to one year a free fat graft is effective in reducing the amount of peridural scarring.

Adipose Tissue↗