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Biomedical subjects

P Broos

Publications and source records attributed to P Broos.

At least 19 recordsLinked to original sources
PubMed2002

A newly designed vertebral replacement implant to reconstruct the thoracolumbar spine anteriorly.

Calcium phosphate compounds are becoming of increasingly great importance in the field of biomaterials and, in particular, as bone substitutes. In this way donor-side morbidity can be avoided. A type A lesion of the vertebral body can be the reason of a neurological deficit, requiring a corpectomy by means of an anterior approach, tricortical bone grafting and internal stabilization to get a fusion over time. It is our aim to introduce in this study a newly designed vertebral replacement device, tested in an animal model, using domestic pigs. Two biomaterials, Cementek and Biobon were primarily macroscopically and microscopically evaluated, using a critically sized bone defect of a vertebral body and compared with autologous bone grafts. The final tests consisted of two groups of four animals. A corpectomy at the level of L4 was created and stabilized by means of the newly designed vertebral replacement implant. Autologous bone grafts were applied in one group of animals and Cementek in the other to fill the remaining space. Fusion was studied using anteroposterior and lateral radiographs, followed by a computer tomography. The biocompatibility of the biomaterials and autologous bone grafts were in order of: Cementek > autologous bone grafts > Biobon. In the final tests after a six months period, a fusion was diagnosed in four cases, two delayed unions, and two obvious non-unions. An analysis of the failures in this animal study can possibly clarify the shortcomings of this concept. Perhaps, subtle changes of the design combined with other synthetic bone substitutes can possibly improve the fusion rate in the near future.

Animals↗
PubMed2001

[Electromyography study of the anterior tibial muscle and accidental falls in the elderly].

This article investigates if surface electromyography of the tibialis anterior muscle during rest, maximal contraction and balance stressing pick out elderly people at risk for falling. With a same view postural responses underlying balance control were recorded as well. Four groups were compared: an experimental group composed of nursing home residents (n = 15) with three or more unexplained falls in the prior year, a nonfalling control group of nursing home residents (n = 15) of equivalent age, a group of subjects (n = 15) in middle age and finally a group of young participants (n = 15). EMG activity during maximal contraction of the tibialis anterior muscle was significantly lower in the falling group and the postural responses during balance testing were inappropriate.

Accidental Falls↗
PubMed2001

The use of 'hybrid' allografts in the treatment of fractures of the thoracolumbar spine: first experience.

Harvesting autogenous bone grafts of the iliac crest carries complications and lengthens operative times. Allografts are preferred to avoid these problems. Fusion after using allogenic bone grafts has been well studied, by examining trabeculations and remodelling on anteroposterior and lateral radiographs. However, the question remains whether one can rely on radiographs alone to determine fusion. 'Hybrid' fresh-frozen allografts from the femur or tibia were used in 11 adult patients with a mean age of 56.4 years (range: 30-78 years) to stabilize the thoracolumbar spine after anterior decompression for trauma. In one case two adjacent levels were fractured, in another case two fractures occurred at different levels. Fresh-frozen allografts of the femur (in ten cases) and tibia (one case), filled with autogenous cancellous bone graft or pieces of rib, were used to reconstruct the anterior column of the spine. Stabilization was performed by means of a Kaneda device. Anteroposterior and lateral radiographs and, additionally, computed tomography (CT) examinations with reconstructions were used to study fusion. One patient died 1 month after surgery. At follow-up in ten patients, after a mean time of 30.2 months (range: 18-42 months), ten allografts showed a grade I fusion and one a grade III fusion. Additional data from the CT examination with reconstructions, however, showed cross-trabeculations in all cases, and a partially united allograft in the patient with a grade III fusion. Cross-trabeculations between the allograft and vertebral body was observed at 6 months, with remodelling occurring at approximately 2 years. Mean loss of correction was minimal, at 3.6 degrees (range 0 degree-16 degrees). Fresh-frozen femoral or tibial allografts worked effectively to maintain correction after trauma when combined with anterior instrumentation. CT examinations with sagittal and coronal reconstructions were more effective for evaluation of fusion compared with anteroposterior and lateral radiographs. The high fusion rate and the low morbidity achieved using allografts in this way supports the exclusive use of allografts in the anterior thoracic and lumbar spine in the future.

Bone Remodeling↗
PubMed2001

Trans iliac-sacral-iliac bar stabilisation to treat bilateral lesions of the sacro-iliac joint or sacrum: anatomical considerations and clinical experience.

The use of trans iliac-sacral-iliac bars is an alternative to sacro-iliac screws in the treatment of bilateral lesions of the posterior pelvic ring, and the same biomechanical principles can be applied. Of 20 patients, ten men and ten women, a CT-scan of the pelvis was performed to study the individual and common safe area at the level of S1 and S2. The location and maximal diameter of the individual safe area were studied using a computer-navigation system, displaying images in sagittal, coronal and axial anatomic planes together with a 3-D reconstruction. The common safe area was studied using three points: upper- (UA) and lower anterior corner (DA) of S1 and S2, and the centre of the safe area. It would have been possible to place an iliac-sacral-iliac bar (5 mm or more) in S1 and S2 in all the men, but in the women a bar could only have been inserted in only five in S1 and eight in S2. A statistically significant difference between men and women was found at S1 (P=0.033) but not at S2 (P=0.211). No significant correlation was found between the diameter of the safe area at both levels in men and women and age, height, and weight. Furthermore, no common safe area of 5 mm or more was measured at the same levels.Four patients were treated using trans iliac-sacral-iliac bars. Three were placed under fluoroscopic control in combination with a frame, and in one patient an image-guided system was used. A postoperative CT confirmed the correct position of the bars in each patient. The complexity and individual variability of the sacrum makes complex preoperative planning of the iliac-sacral-iliac path mandatory.

Adult↗
PubMed2001

Brachial artery injury in closed posterior elbow dislocation case report.

The authors describe a case with a closed posterior elbow dislocation associated with a distal radial fracture and complete transsection of the brachial artery. The patient had a pulseless distal upper extremity and immediate gross swelling of the elbow and forearm. As closed reduction was not possible, open reduction had to be performed through an anteromedial approach to the elbow. End-to-end suture of the brachial artery was successful. After fasciotomy and internal fixation of the distal radial fracture, the elbow was stabilized with an external fixator spanning the elbow joint. After two years, despite good function of the elbow, restoration of the hand function is not optimal owing to persistent motor deficit of the ulnar nerve.

Accidental Falls↗
PubMed2000

Polymorphisms of the VDR, ER and COLIA1 genes and osteoporotic hip fracture in elderly postmenopausal women.

In view of the reported associations between osteoporosis and polymorphisms of the vitamin D receptor (VDR), collagen Ialpha1 (COLIA1) and estrogen receptor (ER) genes, an association study was performed between VDR, COLLIA1, and ER genotypes and bone mineral density, biochemical markers of bone turnover and hip fracture occurrence in Belgian older postmenopausal women. The gene polymorphisms were evaluated by restriction fragment length polymorphism analyses, using the restriction enzymes BsmI (VDR), AccB7I (COLIA1), and PvuII and XbaI (ER), respectively. As expected, bone mineral density and biochemical analyses demonstrated significant differences between hip fracture patients and elderly controls. However, no significant differences in genotype distributions or allele frequencies were observed between the cases (n = 135, age 78 +/- 9 years) and controls (n = 239, age 76 +/- 4 years) for any of the gene polymorphisms. Stratification of both study populations according to VDR, COLIA1 or ER genotype did not reveal any statistically significant difference in bone density or bone turnover between subgroups with different genotypes. In conclusion, despite its limited statistical power the outcome of this study does not support the hypothesis of a major contribution of the VDR, COLIA1 or ER polymorphisms to explain variations in bone mineral density or bone turnover, or to identify elderly women at risk of osteoporotic hip fracture.

Aged↗
PubMed1999

Osteogenic ability of free periosteal autografts in tibial fractures with severe soft tissue damage: an experimental study.

OBJECTIVE: The present study was undertaken to assess whether free nonvascularized autologous periosteum transplants enhance bone healing in a rabbit fracture model designed to resemble a tibial fracture with severe soft tissue damage. DESIGN: Transplantation of free autologous periosteal grafts on the anteromedial site of the tibia (experimental group) was compared with nontransplantation on the contralateral tibia (control group). We produced a standardized transverse osteotomy of both tibial diaphyses in white male adult New Zealand rabbits. The endomedullary cavity was reamed and nailed, and then a one-centimeter segment of periosteum was excised from either side of the osteotomy. To prevent periosteal and extraosseous ingrowth at the osteotomy site, a silastic sheet was wrapped around two-thirds of the circumference of the tibia. In the first group, on the silastic-free bone window, we then spanned the osteotomy with a free, nonvascularized, longitudinally oriented autologous periosteum and sewed it to the adjacent periosteum both proximally and distally. In the second group, the periosteum was placed transversely, leaving a gap between it and the adjacent periosteum proximally and distally. Revascularization of the graft was determined with the colored microsphere technique. MAIN OUTCOME MEASUREMENTS: Histomorphometric analysis of the periosteal callus was done on a transparent grid superimposed on enlarged photographs of the histologic sections. RESULTS: Free, nonvascularized, longitudinally placed autologous periosteum in contact with intact periosteum produced significantly more periosteal callus than was seen in the control group, in which no periosteal graft was used. However, when transversely placed periosteal grafts were set in the silastic-free bone window and there was no contact with surrounding remnants of intact periosteum, no significant difference in callus production was noted when compared with the control. Revascularization of these grafts was seen within one week after transplantation. Bone healing occurred mainly through endochondral ossification. CONCLUSION: Our data suggest that orthotopically placed autologous nonvascularized periosteum retains its osteogenic potential in a poorly vascularized environment such as a tibial fracture with severe soft tissue damage. The effect is enhanced if the graft is in contact with intact periosteum. Histologically, callus formation after periosteal grafting resembles endochondral and intramembranous ossification.

Animals↗
PubMed1999

Down-regulation of the serum stimulatory components of the insulin-like growth factor (IGF) system (IGF-I, IGF-II, IGF binding protein [BP]-3, and IGFBP-5) in age-related (type II) femoral neck osteoporosis.

Both a decrease in bone formation and an increase in bone resorption have been implicated in the pathogenesis of age-related (type II) femoral neck osteoporosis. While the increase in the bone resorption rate has been shown to be partially related to secondary hyperparathyroidism, the mechanisms underlying the decline in bone formation have not yet been identified. The aim of the present study was to test the hypothesis that the bone formation deficit associated with type II osteoporosis might be due to secondary hyperparathyroidism and/or to a deficiency of the insulin-like growth factor (IGF) system. Circulating concentrations of IGF-I, IGF-II, IGF binding protein (IGFBP)-3, IGFBP-4, IGFBP-5, 25-hydroxycholecalciferol (25(OH)D3), and intact parathyroid hormone (PTH) were measured in 50 elderly women after sustaining a hip fracture and in 50 healthy age-matched controls. In addition, serum levels of osteocalcin (OC), skeletal alkaline phosphatase, and N-terminal procollagen peptide and urinary pyridinium cross-links were determined as markers of bone remodeling, and bone mineral density (BMD) was assessed at the proximal femur. In the patient group, serum was drawn within 18 h of the fracture and prior to surgery. Circulating protein concentrations did not change over this time frame. No difference was found between mean IGFBP-4 serum levels in the two groups studied, while mean levels of IGF-I, IGF-II, IGFBP-3, IGFBP-5, 25(OH)D3, and markers of bone formation were significantly lower (p < 0.006) in patients as compared with healthy subjects. Serum PTH and urinary pyridinium cross-links, however, were markedly increased (p < 0.001) in the osteoporotic group. In pooled data from the normal and osteoporotic populations, age-adjusted multiple regression models based on IGF-I, IGF-II, IGFBP-3, and IGFBP-5 were found to be highly predictive of serum OC (R2 = 19%, p < 0.001) and BMD of femoral neck (R2 = 49%, p < 0.0001), consistent with an effect of the anabolic IGF components on overall bone formation rate. Similar models based on 25(OH)D3 and PTH, however, were statistically unrelated to OC. To address further the potential impact of trauma on circulating IGF system components, we measured IGF system component levels in 10 male patients within 18 h following tibial fracture and in 10 age-matched normal male subjects. There was no significant difference in serum level of any of the IGF system components between the two groups. Although limited by its cross-sectional design, the present study suggests that, in addition to bone resorption resulting from secondary hyperparathyroidism, impaired bone formation associated with deficiency of the IGF system might predispose elderly women to fragility fracture of the proximal femur.

Age Factors↗
PubMed1999

Factors associated with hip fracture occurrence in old age. Implications in the postsurgical management.

Fractures of the proximal femur (intracapsular as well as trochanteric fractures) are the most devastating complication of osteoporosis. These fractures are not only associated with significant morbidity, but also with a severe risk of death (+/- 25%) within one year. The strongest predisposing factor for fractures of the proximal femur is low bone density. In addition, numerous studies provide evidence that several other factors, independently, contribute to hip fracture risk, including low body mass index, previous fractures, muscle weakness, impaired vision, cognitive impairment, history of hyperthyroidism, use of long-acting sedatives, and physical inactivity. These findings indicate the need for preventive strategies based on risk factor modification and also on measures to maintain bone density. In view of the growing incidence of subsequent fracture of the contralateral hip, preventive strategies should be initiated in all these patients as an integral part of the postsurgical management during the acute hospital stay. These strategies should not only include combined supplements of calcium and vitamin D to attenuate further bone loss, but also a comprehensive assessment of risk factors.

Aged↗
PubMed1998

Measurement of skeletal flow with positron emission tomography and 18F-fluoride in femoral head osteonecrosis.

Positron emission tomography (PET) with 18F-fluoride was utilized to determine the regional blood flow to the femoral head in early osteonecrosis. Five patients with a history of unilateral hip trauma and a normal contralateral side were selected. Skeletal flow and fluoride uptake in the abnormal and normal hips were compared directly, and the relation between bone blood flow and final outcome, i.e., surgical replacement or conservative treatment, was evaluated. In this pilot study, a flow ratio of at least 2 between the abnormal and normal femoral head was necessary to predict a successful outcome with a conservative regimen. A minimum flow of 0.04 ml/min/ml was measured in one patient whose affected femoral head healed conservatively. Our preliminary study indicates that this type of highly technical investigation appears feasible in clinical practice and permits prediction of the outcome depending upon regional skeletal flow measurements in vivo.

Adult↗
PubMed1998

Surgical treatment of post-traumatic pelvic deformities.

Two patients with nonunion and malunion of an unstable pelvic fracture, presenting with pain and gait abnormality, were successfully treated with a pelvic reconstruction. The surgical repair consisted of a three staged procedure to perform the osteotomy, the reduction and the internal fixation. Both patients were satisfied with their outcome and experienced no complications.

Adult↗
PubMed1998

The importance of the distal radioulnar joint in distal radial fractures.

In a prospective study we evaluated the results of 272 distal radial fractures by their involvement of the distal radioulnar joint. Impaired function following altered anatomy at the distal radius can be explained by dysfunction of the distal radioulnar joint. Ulnar styloid avulsions contribute to a poorer result because of their effect on distal radioulnar joint function.

Colles' Fracture↗
PubMed1998

The clinical importance of carpal instabilities following distal radial fractures.

A prospective study was undertaken to determine the clinical importance of the different carpal instabilities following dorsally displaced distal radial fractures (Colles' type). All patients were followed for 1 year and a Cooney score and X-ray evaluation were done. Nine different carpal instabilities were evaluated. Only dissociative DISI and ulnar translocation showed significant clinical differences at 1 year follow-up. It is therefore recommended that a dissociative DISI, usually caused by scapholunate dissociation, should be treated by percutaneous pinning at the time of the initial treatment.

Colles' Fracture↗
PubMed1998

Minimally displaced distal radius fractures: do they need plaster treatment?

In a prospective, randomized trial, minimally displaced distal radius fractures were divided into two groups: those treated with plaster immobilization for 1 week compared with 3 weeks. Functional Cooney scores were determined at 6 weeks, 3 months, 6 months, and 1 year. No statistical differences could be found in functional outcome between the groups at any time during the evaluation. Although patients did not allow immediate functional treatment in the presence of a fracture, we could not find any differences between 1 week or 3 weeks of plaster treatment. No further dislocation occurred, and all patients experienced eventful healing with good and excellent results in 92% of the cases. We believe, therefore, that only minimal immobilization is required in these fractures and that they should be mobilized as soon as comfort allows.

Activities of Daily Living↗
PubMed1998

Unreamed intramedullary nailing of acute femoral shaft fractures using a traction device without fracture table.

The authors present a simple distraction apparatus that makes it possible to perform nonreamed intramedullary nailing of the femur on a normal operating table. Nonreamed intramedullary (IM) nails were inserted in 24 femoral shaft fractures using this device. The setup time of this device was 60% shorter compared with a stratified group of 28 femoral nailings performed using the fracture table. The authors feel that this device is a safe and effective alternative to using a fracture table. It is especially useful in the polytrauma patient where the additional lesions can be treated without the need for patient transfer to another table.

Adult↗
PubMed1998

The osteogenic potential of free periosteal autografts in tibial fractures with severe soft tissue damage: an experimental study.

The present study was undertaken on 80 adult male New Zealand rabbits to assess the effect of free nonvascularized, autologous, periosteum transplants on bone healing in a rabbit fracture model comparable to a tibial fracture with severe soft tissue damage. Comparison was made between transplantation of free autologous periosteal grafts on the anteromedial side of the tibia and nontransplantation on the contralateral tibia (control). We produced a standardized transverse osteotomy of both tibial diaphyses. The medullary cavity was reamed and nailed ; a 1-cm segment of periosteum was excised from either side of the osteotomy. Periosteal and extraosseous ingrowth was prevented at the osteotomy site by a silastic sheet wrapped around two-thirds of the circumference of the tibia. On the silastic-free bone window, in one group we spanned the osteotomy with a free nonvascularized longitudinally-oriented autologous periosteum sewn to the adjacent periosteum proximally and distally. In the second group, the periosteum was placed transversely with a gap between it and the adjacent periosteum proximally and distally. Revascularization of the graft was determined with the colored microsphere technique. Our data suggest that orthotopically-placed autologous nonvascularized periosteum retains its osteogenic potential in a poorly vascularized environment comparable to a tibial fracture with severe soft tissue damage ; the effect is enhanced if the graft is in contact with intact periosteum. Histologically, callus formation after periosteal grafting resembles endochondral and intramembranous ossification.

Animals↗
PubMed1998

The pathophysiology of the acute compartment syndrome.

The acute compartment syndrome is a condition in which increased pressure within a limited space compromises the circulation and function of the tissues therein, resulting in tissue ischaemia, necrosis and nerve damage. This rise in tissue pressure originates in a decrease of the compartment size or increase of the intracompartmental volume by oedema and/or haemorrhage. Following the arterio-venous gradient theory, capillary blood flow may be impaired through increased venous pressure, decreased arterial pressure and increased peripheral vascular resistance. Often, compartment syndromes develop during reperfusion following a period of ischaemia. During ischaemia, there is a gradual depletion of intracellular stores of high energy phosphate bonds and glycogen stores. There is a buildup of products of glycolysis, particularly lactic acid, with accompanying hydrogen ion accumulation as well as an increase in intracellular reducing agents. Reperfusion may, instead of restoring normal muscle metabolic activity, cause harmful effects by washing out necessary precursors for adenine nucleotide resynthesis. Production of oxygen free radicals occurs with ensuing lipid peroxidation, and calcium influx occurs upon reoxygenation with resultant disruption of oxidative rephosphorylation in the mitochondria. Furthermore, several lines of evidence suggest that white blood cells are important in the pathogenesis of reperfusion injury. Upregulation of both neutrophil receptors and endothelial leucocyte adhesion molecules leads to the sequestration of white blood cells in the muscle with prolongation of the reperfusion injury. This subsequently results in damage to remote organs such as lungs, liver, heart and kidneys.

Acute Disease↗