Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Fixatives”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources
PubMed1999

Biodegradable semirigid plate and miniscrew fixation compared with rigid titanium fixation in experimental calvarial osteotomy.

OBJECT: To determine the biocompatibility and suitability of resorbable plates and miniscrews, consolidation of symmetrical, bilateral frontal bone craniotomies that had been closed using various methods was studied in 20 growing lambs. METHODS: Bone fixation with a flexible, punched polylactide plate and four slowly degradable, self-reinforced poly-levolactide (SR-PLLA) or rapidly degradable, self-reinforced polyglycolide (SR-PGA) miniscrews (10 animals in each group) was compared intraindividually with rigid fixation by using a titanium miniplate and four miniscrews. Plain x-ray films, magnetic resonance images, histological studies, and histomorphometric studies were obtained at 4 to 104 weeks. CONCLUSIONS: No dislocation, instability, clinical foreign body reactions, infections, or loss of fixation were observed. Bone consolidation of the 2.35-mm-wide craniotomy lines was incomplete; connective tissue-filled defects through the bone were observed in 13 of 28 lines at 26 to 52 weeks. Statistical analyses based on histomorphometric studies showed no difference in consolidation with SR-PLLA miniscrew and titanium plate/screw fixation or between the two resorbable fixation methods. Fixation with rapidly degradable SR-PGA miniscrews resulted in less effective consolidation than on the contralateral titanium-treated side (p<0.05), but the bone segment was thicker (p<0.005). The SR-PGA miniscrews had disappeared by 6 weeks, the polyactide plate by 104 weeks, and the SR-PLLA miniscrews had been mostly resorbed at 104 weeks. Passive translocation of the titanium plates and screws into the bone tissue was seen at 52 and 104 weeks. In rapidly growing lamb frontal bone, comparable consolidation results, without complications, can be achieved with semi-rigid resorbable fixation compared with rigid metallic fixation.

Absorbable Implants↗
PubMed1987

The antiglide plate for distal fibular fixation. A biomechanical comparison with fixation with a lateral plate.

Posterior antiglide plates recently have been introduced as a method of fixation for the short oblique fracture (Type B, as defined by the AO Group) of the distal part of the fibula. This method has several advantages over the more commonly used lateral plate for the fixation of this type of fracture, including dissection of a smaller area and less operative time, minimum bending of the plate, and no potential for penetration of a screw into the joint. The system can also be applied without insertion of a screw into the distal fragment. This prompted us to compare the biomechanical properties of fixation with the antiglide and lateral plating systems. Short oblique fractures of the distal part of the fibula were produced mechanically in cadaveric legs by supination and external rotation of the foot. The torque that was necessary to produce the fracture in each of twenty-four fibulae was recorded. After fracture, each fibula was reduced anatomically and fixed internally with a lateral plate or antiglide plate applied posteriorly. The strength of fixation was measured by restressing the legs until failure of fixation occurred. The stiffness of the fixation system and the amount of energy required to produce failure of fixation were also calculated. The system using the lateral plate for fixation failed when the torque reached an average of 64.3 per cent of the torque that produced the fracture.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomechanical Phenomena↗
PubMed1993

Mechanical performance of Ilizarov circular external fixators in comparison with other external fixators.

The fundamental difference of the Ilizarov fixator is the type of pins used for bone fixation, i.e., Kirschner wires 1.5 mm and 1.8 mm in diameter, pretensioned from 50 to 130 kg before being affixed to the rings that are connected and fixed by threaded rods. The mechanical characteristics of external fixators may influence the biologic environment at the fracture site and ultimately decide the outcome of a surgical procedure. Thus, knowledge of the mechanical properties of the Ilizarov fixator is essential to a surgeon using it in clinical practice. The main objective of this study was to quantitate the mechanical behavior of the standard Ilizarov fixator under different loading conditions and fixator frame/wire configurations. The fixator was found to have a nonlinear stiffness behavior under axial compression. The nonlinearity in axial stiffness also varied with wire pretension. Such characteristics, however, were not as pronounced under torsion and bending loads within the test range studied. Besides the wire pretension, the most important factor affecting the structural stiffness of the Ilizarov device was the diameter of the wire. Offset bone position provided greater stiffness in loads up to 45 kg in axial compression, in torsion up to 5 degrees of rotation, and in the final loading range under bending. Fixators with wires crossing at 45 degrees had significantly greater stiffness in torsion as compared with 90 degrees crossing wires, but the opposite was true in axial compression. Torsional stiffness increased significantly under coupled axial compression applied through the bone ends. All four-point bending tests demonstrated two distinct stiffness curves that were probably due to slippage of the bone model on the wires. This information should help to understand the mechanical behavior of the Ilizarov device and thereby improve its clinical performance.

Bone Lengthening↗
PubMed1995

Comparison of fixation disparity curve variables measured with the Sheedy Disparometer and the Wesson Fixation Disparity Card.

BACKGROUND: Previous studies suggest differences in the fixation disparity curves obtained with the Sheedy Disparometer and the Wesson Fixation Disparity Card, the two most commonly used methods for measuring fixation disparity. In one study the investigators proposed that the differences do not exist for subgroups divided by phoria. The purpose of this paper is to try to clarify this issue by use of two large sets of data. METHODS: Dissociated phorias were measured by the von Graefe method. Fixation disparity curves were plotted using the Disparometer and the Wesson card. RESULTS: Type I fixation disparity curves were most common with the Wesson card. Type II curves were found more often with the Disparometer than with the Wesson card. The x-intercepts were shifted in the base-in (BI) direction with the Wesson card compared to the Disparometer. The y-intercepts were shifted in the exo direction with the Wesson card compared to the Disparometer. The differences were statistically significant regardless of whether the dissociated phoria was exo or eso. The slope of the fixation disparity curve was steeper with the Wesson card than with the Disparometer. The difference was statistically significant for exophores but not for esophores. The differences between results obtained with the two instruments are not consistent from one subject to another as shown by high standard deviations of the differences. CONCLUSIONS: The fixation disparity curves measured with these two instruments are different. Fixation disparity parameters obtained from one of these instruments cannot be used with normative findings from the other.

Evaluation Studies as Topic↗
PubMed1995

External fixation and limited internal fixation for complex fractures of the tibial plateau.

Twenty-one complex fractures of the tibial plateau in twenty patients were treated with closed reduction, interfragmental screw fixation of the articular fragments, and application of a unilateral half-pin external fixator. The average duration of external fixation was twelve weeks (range, three to twenty weeks). The fixator was left in situ until the fracture had united in all but two patients. All of the fractures healed. The complications with this technique were attributable primarily to the proximal half-pins of the external fixator. Seven patients needed antibiotics for an infection at a pin site, and two had septic arthritis that necessitated arthrotomy and débridement. The average duration of follow-up was thirty-eight months. The range of motion of nineteen of the twenty-one knees was at least a 115-degree arc. Laxity was evident in seven knees, but no patient complained of instability of the knee. Radiographs showed malalignment of more than 6 degrees in three knees compared with the normal, contralateral knee and evidence of post-traumatic osteoarthrosis in five knees. The Iowa knee score, determined for nineteen patients, averaged 87 points (range, 55 to 100 points). The SF-36 general health survey demonstrated that most patients had function close to that of age-matched controls. We concluded that external fixation with limited internal fixation is a satisfactory technique for the treatment of selected complex fractures of the tibial plateau.

Adult↗
PubMedDate not supplied

Our fixation with fixation: are screws clinically superior to external wires in distal first metatarsal osteotomies?

The purpose of this study was to evaluate the immediate postoperative morbidity, the structural correction attained, and the long-term range of motion following fixation with a single external Kirschner wire and an internal cortical screw. We abstracted records for 69 patients undergoing, distal unicorrectional chevron osteotomies. Thirty-three patients received percutaneous 0.062-inch K-wire fixation and 36 patients received single 2.7-mm. cortical screw fixation. Among these age- and sex-matched subjects, there was not a significant difference between any of the correctional or morbid outcomes measured in this study on the basis of type of fixation employed. Patients with rigid internal screw fixation did not return to shoe gear sooner, develop fewer postoperative infections, or have increased long-term range of motion than the group receiving external fixation with a single K-wire. Surgical time was significantly longer for those patients undergoing rigid internal fixation with a screw (42.5 +/- 9.5 vs. 35.1 +/- 6.6 minutes, p < 0.001). We conclude that there is no significant difference in postoperative infection, dehiscence, long-term structural correction attained, or range of motion achieved between rigid internal screws and external K-wires used to fixate distal metatarsal osteotomies.

Bone Screws↗
PubMed1976

Studies to improve fixation of human nerves. V. Effect of temperature, fixative and CaCl2 on density of microtubules and neurofilaments.

Utilizing morphometry of electron micrographs of nerves of rat fixed with different schedules of fixation it was concluded that: irrespective of the fixative, fixation at low temperature is associated with markedly low densities of microtubules (MT) of myelinated and of unmyelinated fibers; of the various fixatives tested 2% glutaraldehyde in 0.1 M cacodylate buffer without 0.025 M CaCl2 was associated with the highest density of MT of myelinated fibers and the addition of 0.025 M CaCl2 to a 2% glutaraldehyde fixative solution is associated with abnormally low densities of MT in myelinated and unmyelinated fibers. An effect of temperature, fixative and added CaCl2 on neurofilaments density was not demonstrated. Using the criterion of density of MT and assuming that these studies on rat nerves can be applied to biopsied nerve of man, fixation of human nerves should be at room or body temperature, and the fixative solution should not contain 0.025 M CaCl2.

Animals↗
PubMed1994

Prompt fixation of isolated femur fractures in a rural trauma center: a study examining the timing of fixation and resource allocation.

Early fixation is defined by most authors as fracture fixation within 24 hours of admission. This definition of early is arbitrary and may not be achievable in a rural environment where interhospital transfer is often required and operating room resources are constrained. A review of isolated femur fractures was performed to determine if prompt fixation (24-72 hours, Early) was more effective than late fixation (> 72 hours, Late) and similar to immediate fixation (< 24 hours, Immediate) with regard to complications, mortality, and resource utilization. Between October 1, 1987 and December 31, 1990, 67 patients were admitted and stratified into one of the three groups based on the timing of fixation. The number of emergency operations was significantly greater in the Immediate group and the surgery took significantly longer to perform than in either the Early or Late groups (p < 0.004; ANOVA). There were significantly fewer pulmonary and infectious complications in the Immediate and Early groups compared with the Late group (p < 0.05, chi 2). Fixation of isolated femur fractures after 24 hours but before 72 hours had morbidity similar to fixation within the first 24 hours, but utilized operating room resources more efficiently.

Adult↗
PubMed2004

Endoscopic ACL reconstruction using stryker biosteon cross-pin femoral fixation and interlock cross-pin tibial fixation.

Hamstring tendon autografts have, over the past decade, increasingly become the graft of choice for anterior cruciate ligament (ACL) reconstructions. Studies have shown that multiply stranded hamstring grafts have superior biomechanical characteristics when compared to patellar tendon autografts. Harvests of hamstring tendons have been shown to cause less donor-site morbidity than the harvest of patellar bone-tendon-bone grafts. Historically, however, fixation methods for hamstring grafts have limited their successful use. Fixation for both the tibia and femur distant from the intra-articular portions of the graft decreased the stiffness of the construct. The fixation also contributed to tunnel widening and ganglion formation. New methods have been developed to maximize the mechanical strengths of hamstring grafts and optimize biological factors in healing of the graft to the bone tunnels. Femoral cross-pin fixation provides secure fixation close to the knee joint, while also allowing for placement of the graft in the native ACL footprint at the far posterior aspect of the intercondylar notch. Tibial interference screw fixation allows fixation close to the joint as well. Addition of the interlock pin through the interference screw increases pullout strength significantly. Recent advances in material science have led to the development of bioabsorbable implants that afford high initial fixation strengths while limiting subsequent complications from permanent hardware.

Anterior Cruciate Ligament Injuries↗
PubMed1996

[Supportive composite-hybrid fixation of percutaneous screw fixation of tibial head fractures].

Recent operative techniques with percutaneous screw fixation of the tibial plateau require a high level of patient compliance. Geriatric, non-cooperative patients and fractures with severe soft tissue injury have had to be excluded so far from this therapeutic regimen. Since September 1993, composite hybrid fixation, as a combination of ring fixation of the epimetaphyseal tibia with monolateral AO fixation of the tibial shaft, has been performed in 12 patients. The data were collected prospectively. Fractures were classified according to the AO and Moore classification; soft tissue damage was classified according to Tscherne and Gustilio. Fixation was performed with the cannulated AO system, 2.0 mm titanium K wires and 5.0 mm AO Schanz screws. In five patients, additional arthroscopic control of the reposition was performed. Average removal of the external fixator was 16 weeks postoperatively. Pin-tract infections occurred in all patients, mainly in the metaphyseal region. In one patient, a knee infection resulted from a subchondral intra-articular pin, which was treated by repetitive arthroscopic synovectomy. In two patients, a secondary loss of reposition (5-7 degrees varus) occurred. Despite a high rate of soft tissue damage (8/12), no osteitis or non-union occurred. As an alternative to extensive methods of ORIF, supportive composite hybrid fixation offers a new perspective of early functional treatment, weight bearing and a rare loss of reposition. It is favored in geriatric, non-cooperative patients and in fractures with severe soft tissue damage.

Adult↗
PubMed2003

Three-dimensional stabilization provided by the external spinal fixator compared to two internal fixation devices: a biomechanical in vitro flexibility study.

We performed an in vitro study to investigate the stabilization (i.e. motion reduction) provided by the external spinal fixator (ESF), and to compare the three configurations of the ESF with two internal fixation techniques. Six human cadaveric lumbar spine specimens (L3-S1) were subjected to multidirectional flexibility testing in six configurations: (1) intact, (2) ESF in neutral, (3) ESF in distraction, (4) ESF in compression, (5) translaminar facet screw fixation, and (6) internal transpedicular fixation. Both the ESF and the internal fixation systems stabilized the specimens from L4 to S1. In each testing configuration, pure bending moments of flexion-extension, bilateral axial rotation, and bilateral lateral bending were applied to the uppermost vertebra stepwise to a maximum of 10 Nm. The rigid body motion between the vertebrae was measured using an optoelectronic camera system, and custom software was used to calculate the intervertebral rotations. For each applied motion in all testing configurations, the total range of motion (ROM) of L4-S1 is reported. All three ESF configurations stabilized the spine significantly when compared to the intact specimen. The ESF in compression provided significantly more stabilization in flexion-extension than the two other ESF configurations, but no other significant differences were found between the three ESF modes. In flexion-extension the ESF stabilized the spine significantly when compared with the two internal fixation devices. Only in bilateral lateral bending was the ESF inferior to internal transpedicular fixation in providing stabilization. The results of the present study suggest that the ESF provides a high degree of stabilization for preoperative assessment of selected low back pain patients. Whether other non-mechanical factors affect the pain relief experienced by the patients remains unknown.

Adult↗
PubMed2006

Effects of fixative type and fixation time on the detection of Maedi Visna virus by PCR and immunohistochemistry in paraffin-embedded ovine lung samples.

In doubtful cases, the histopathological diagnosis of lesions induced by Maedi Visna virus (MVV), a chronic multisystemic lentiviral disease of sheep, needs to be confirmed by the demonstration of MVV in the tissues. The influence of fixatives and the duration of fixation on the detection of MVV by immunohistochemistry (IHC) and PCR in paraffin-embedded tissues was assessed in lung samples with lesions in different degree, from five sheep serologically positive. Samples were fixed in 10% neutral buffered formalin (NBF), Bouin's solution (BS) and a zinc salts-based fixative (ZSF), for different periods of time between 24 h and 30 days. The three fixatives preserved the morphology of the tissues, although in ZSF-fixed samples an increase in the number of desquamated cells was seen in the alveoli. Tissues showed a similar degree of immunolabelling, irrespective of the duration of fixation using ZSF and NBF fixatives. MVV nucleic acids could be detected in samples fixed up to 14 days in NBF and 30 days in ZSF. However, in BS fixed tissues, immunostaining was weak and non-specific signals were observed after 4 days of fixation. Amplification of proviral DNA could not be obtained by PCR in these samples. IHC detected viral antigens in all sheep whereas one sheep with mild lesions was always negative by PCR.

Acetic Acid↗
PubMed2002

Improvement of external fixator performance in type C pelvic ring injuries by plating of the pubic symphysis: an experimental study on 12 external fixators.

BACKGROUND: In an earlier study, we introduced a pelvic ring stability criterion for weightbearing stabilization. In a loading test, however, current external fixation systems alone did not meet this criterion. Internal fixation of the dorsal ring can significantly increase stability, but the condition of severely injured patients is often a contraindication for major surgery. The aim of this study is to optimize external pelvic ring fixation without dorsal ring stabilization to allow weightbearing in early mobilization of patients with unstable pelvic ring injuries. METHODS: The stiffness of external fixation systems alone and in combination with one or two anterior plates was measured by using a pelvic replica with a type C pelvic ring injury. Endpoints were 15 mm of dislocation or tolerance of 560 N. RESULTS: Addition of one plate at least doubles stiffness, whereas two-plate fixation results in at least a fourfold stiffer configuration. Frame configurations profit more than single-bar systems, and all but one system resist the weightbearing load after double-plating of the pubic symphysis. CONCLUSION: The choice of double-plate fixation of the anterior ring in addition to external fixation results in weightbearing capacity.

Biomechanical Phenomena↗
PubMed2003

Intramedullary rod fixation compared with blade-plate-and-screw fixation for tibiotalocalcaneal arthrodesis: a biomechanical investigation.

BACKGROUND: Achieving stable fixation when performing tibiotalocalcaneal arthrodesis can be challenging, especially in osteopenic bone. The purpose of the current investigation was to compare the stiffness and fatigue endurance of blade-plate-and-screw fixation with intramedullary rod fixation in a cadaveric model. METHODS: In ten matched pairs of fresh-frozen cadaveric legs, a tibiotalocalcaneal arthrodesis was performed with use of a blade-plate and a 6.5-mm sagittal screw in one leg and with use of an intramedullary rod in the contralateral leg. After an initial load-deformation curve was obtained, each specimen was loaded to 270 N through 250,000 cycles at a rate of 3 Hz. RESULTS: Blade-plate-and-screw fixation resulted in significantly higher mean initial and final stiffness and decreased plastic deformation than did intramedullary rod fixation. In addition, there was an inverse correlation between bone-mineral density and the difference in plastic deformation noted between the specimens of each pair. CONCLUSIONS: Blade-plate fixation is biomechanically superior to intramedullary fixation for tibiotalocalcaneal arthrodesis.

Analysis of Variance↗
PubMed1992

[External fixator in complicated tibial fracture. Effect of various fixation systems on fracture healing and rate of complications].

In a retrospective analysis 93 external fixations with different rigidity after open tibial shaft fractures have been reviewed and compared concerning complications and healing time. Fracture consolidation was attained in fixation with unilateral frame after 14 weeks, with bilateral v-shaped fixator after 19 weeks and with triangular configuration in about 28 weeks. Subsequent internal fixation or extension to v-shaped fixation was necessary in about 33% after initial unilateral half-pin frame, whereas 90% of the two rigid systems could be left in situ until fracture consolidation was achieved. Cancellous bone grafts were performed in 58% after triangular, in 40% after v-shaped, and 28% after unilateral fixation. Pin infections were observed in 36% after triangular, 25% after bilateral v-shaped, and in 15% after unilateral fixation.

Adult↗
PubMed2002

Treatment of complex proximal humeral fractures with minimally invasive fixation of the humeral head combined with flexible intramedullary wire fixation - introduction of a new treatment concept.

The treatment of three- or 4-part proximal humerus fractures is still a matter of scientific discussion. The following study presents the results of a combined procedure using limited invasive fixation techniques for reconstruction of the humerus head and retrograde intramedullary wiring with elastic nails for the treatment of displaced three- or 4-part fractures. A prospective study of 24 patients with 3-part and 4-part fractures was performed from September 1995 to December 1998. Combined biologic fixation for reconstruction of the humerus head, including intramedullary wiring, was utilized. Fracture reduction was performed in an open soft-tissue-preserving technique through a limited lateral approach. Fixation of the head fragments was performed using screw and/or cerclage wire fixation. The reconstructed humerus head was stabilized to the shaft with intramedullary wires, with retrograde insertion 2 cm above the olecranon fossa. Supportive fixation of the head fragments was achieved using fully threaded cancellous screws. At the 1-year postoperative follow-up, 40% of the 18 patients had excellent results using the Neer and Constant score. Forty-five percent had satisfactory and 15% unsatisfactory results. The initial results of this study reveal that a combination of limited internal fixation of the humerus head and retrograde elastic intramedullary wiring provide stable fixation with limited soft-tissue destruction. This approach has been shown to be especially useful for the combined treatment of three- or four-part fractures of the humeral head.

Adult↗
PubMed2000

Comparison of biomechanical properties of periosteal suture fixation and bone anchor fixation to the pubic bone.

OBJECTIVES: To compare the relative strength of fixation using bone anchors (BAs) compared with direct suture placement into the periosteum. METHODS: The anterior bony pelvis was harvested from 21 female cadavers. In each pelvis, BA suture fixation was performed using Cinch anchors on one side of the pubic bone and direct periosteal suture fixation (PSF) on the contralateral side of the same pelvis. We used No. 1 polyproprolene suture for all cases. Using a hydraulic mechanical testing machine, all specimens were loaded in uniaxial tension until failure. RESULTS: Failure modes for BA-fixed pelves were as follows: 11 BA pull-out, 1 midsuture failure, and 9 suture cut by BA. Failure modes for the PSF pelves were as follows: 6 suture pull-outs through the bone, 14 midsuture failures, and 1 suture cut at the bone. PSF pelves required significantly higher loads to induce failure compared with BA pelves (PSF 92.63 +/- 22.62 N, BA 71.32 +/- 19.76 N, P <0.0002). In many cases, both PSF and BA were adequate points of fixation, and the major mechanism of failure was suture rupture. In pelves with suture failure, the load to induce failure was significantly higher in the PSF group (PSF 105.06 +/- 12.55 N, BA 86.06 +/- 7.78 N, P <0.0025). When the suture failed, PSF was better because BA fixation actually broke some sutures. The load required to induce failure was higher in the PSF groups in 19 (90.5%) of 21 pelves. CONCLUSIONS: Biomechanical testing using permanent monofilament suture did not demonstrate a superiority of BA suture fixation to PSF fixation. PSF appears superior, since BAs induced suture failure in many cases.

Biomechanical Phenomena↗
PubMed1995

Flexibility and distraction after monosegmental and bisegmental lumbosacral fixation with angular stable fixators.

STUDY DESIGN: In human lumbosacral spines, the flexibility and intersegmental distraction allowed by four monosegmental and bisegmental intrapedicular devices during compression and flexion/compression loading were investigated. OBJECTIVES: To compare the flexibility and intersegmental distraction allowed by four monosegmental and bisegmental intrapedicular, lumbosacral fixation devices applied to destabilized cadaveric spines, and to determine the effect of each device on the flexibility and intersegmental distraction of the motion segment above each fused segment. SUMMARY OF BACKGROUND DATA: The lumbosacral segment is the most mobile region in the lumbar spine, exhibiting the highest range of motion in both flexion and extension. Therefore, the fixation of this and the adjacent segment is of special clinical interest. METHODS: L5-S1 facetectomy or L5 laminectomy procedures were performed on cadaveric human lumbosacral spines. Fixation devices then were applied across one or two levels, and intersegmental motion under flexion/compression or under pure compression loads was monitored. RESULTS: The flexibility and posterior strain allowed by the four implants did not differ significantly between implants. The strain across the stabilized site (monosegmental and bisegmental) was below 10% for all devices tested. The flexibility and distraction were reduced to levels below intact after the fixators were applied. The distraction across the segment above the fusion was not increased because of fixation with these four fixators. CONCLUSIONS: Angular stable fixation devices, such as those described here, provide adequate stabilization of the posteriorly destabilized spine.

Adult↗