Rigid Fixation

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The hierarchy of stability and predictability in orthognathic surgery with rigid fixation: an update and extension

The hierarchy of stability and predictability in orthognathic surgery with rigid fixation: an update and extension

Problematic stability in moving the maxilla down is due largely to changes within the first few postsurgical weeks, before bone healing is complete, as occlusal force tends to push it upward (Figure 12). There are three logical approaches to maintaining the position of the maxilla until it heals: heavy rigid fixation, a rigid hydroxyl apatite graft in the defect created by the downward movement, and simultaneous mandibular surgery to decrease the occlusal force. All are reasonably successful, but the rigid fixation has to be much heavier than typical plates and screws and still is not completely effective. An initially rigid but ultimately resorbable graft, rather than one like hydroxyl apatite that persists indefinitely, is likely to become available in the near future and would be pre- ferred. Improved stability has been demonstrated in patients (usually Class III) in whom downward move-

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Study of outcome following rigid fixation of mandibular fractures without per operative operative or post operative maxillo mandibular fixation and immediate mobilisation: A prospective study

Study of outcome following rigid fixation of mandibular fractures without per operative operative or post operative maxillo mandibular fixation and immediate mobilisation: A prospective study

This is to certify that this dissertation titled “STUDY OF OUTCOME FOLLOWING RIGID FIXATION OF MANDIBULAR FRACTURES WITHOUT PER OPERATIVE OR POST OPERATIVE MAXILLO- MANDIBULAR FIXATION AND IMMEDIATE MOBILISATION – A PROSPECTIVE STUDY” is a bonafide research work done by Dr.R.Subashini, M.Ch., Postgraduate student of Plastic Surgery, Department of Plastic Surgery and IRRH, Stanley Medical College, Chennai – 600 001. This dissertation was done under my guidance and direct supervision during the period of October 2010 to September 2012. This dissertation is submitted to The Tamilnadu Dr.M.G.R. Medical University, Chennai in partial fulfillment of the award of M.Ch. Degree in Plastic Surgery.

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Operative management of calcaneal fractures with tentacle plate: A short-term prospective outcome analysis

Operative management of calcaneal fractures with tentacle plate: A short-term prospective outcome analysis

The success is mainly because of rigid tentacle plate kept the fragment in good position (33) and avoiding the early load bearing also important in preventing collapse. In this series minimum time taken for partial weight bearing was 2 months & for full weight bearing was 3 months. Depending upon the fracture pattern, comminution, anatomical reduction & fixation the weight bearing was started. Weight bearing was started earlier (8 wks) in those cases with type-II fractures, good anatomical reduction & rigid fixation, without comminution,

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A prospective study of midfoot osteotomy combined with adjacent joint sparing internal fixation in treatment of rigid pes cavus deformity

A prospective study of midfoot osteotomy combined with adjacent joint sparing internal fixation in treatment of rigid pes cavus deformity

The usual methods of internal fixation include K-wire and stapling, both of which are not reliable enough to permit early functional exercises [24,25]. A different in- ternal fixation tool, the cannulated screw, is believed to be a good choice to compress the osteotomy site. How- ever, to acquire a rigid fixation, the screw must cross the adjacent joints, such as the talonavicular joint, the calca- neocuboid joint, the tarsometatarsal joint and the subta- lar joint, which are all amphiarthrodial joints. Therefore, early exercise is likely to result in pain, injury to the ar- ticular cartilage and internal fixation rupture. To avoid the above complications, we applied three cannulated screws to fix the osteotomy between the Lisfranc line and the Cyma line. Our method permitted early exercise,

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Evaluation of Gamma Nails in Intertrochanteric Fractures of Femur and Modified Technique for Removal

Evaluation of Gamma Nails in Intertrochanteric Fractures of Femur and Modified Technique for Removal

Sufficient reduction and rigid internal fixation are still the best methods for unstable IFF. Because of its bio- mechanical and anatomical design, proximal femoral nail (PFN) is a fixation material that has started to be in- creasingly used by orthopedic surgeons recently. However, the use of rigid fixation methods and problems with implant following operation are troublesome because of accompany of osteoporosis in unstable fractures in elder patient group [5] [6].

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Study on the clinical application of pulsed DC magnetic technology for tracking of intraoperative head motion during frameless stereotaxy

Study on the clinical application of pulsed DC magnetic technology for tracking of intraoperative head motion during frameless stereotaxy

the measurement accuracy of image data registration. The FRE describes the distance between the position of a fidu- cial localized in the image data and the position measured in the operation site and transformed into the image coor- dinate system by means of the registration image. Impor- tant factors are the error in the positional measurement system used in determining the position in the operation site and the accuracy of the localization of the fiducial positions in the image data set. Statistical analysis of the FRE measurements in the patients of our study shows that there are no significant differences in mean registration accuracies between rigid 3-point pin fixation with (types B1 and B2) and without (type A) use of a DRF. This result suggests that there is no immediate benefit from the use of an additional DRF in terms of accuracy of image data reg- istration. The registration accuracies in patients without rigid fixation of the head (types C1 and C2) did not differ significantly between oral and retroauricular attachment of the DRF. However, FRE values for types C1 and C2 were significantly higher (on average 10–15%) than in patients with rigid pin fixation. This may be caused by inadvertent micro movements of the Fiducial positions during the reg- istration procedure, e.g. due to the effect of respiration on the unfixed head. Nevertheless, also C1 and C2 type val- ues seem to be in an acceptable range for microneurosur- gical procedures (means: C1 = 1.73 mm +/-SD; C2 = 1.75 mm +/- SD) as they compare well with those achieved with other standard navigation techniques since most commercial navigation systems assume registration to be successful if the FRE is less than 3 mm.

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Original Article Surgical effects and prognosis of non-rigid internal fixation for ankle fractures combined with tibiofibular syndesmotic injuries

Original Article Surgical effects and prognosis of non-rigid internal fixation for ankle fractures combined with tibiofibular syndesmotic injuries

In this study, AOFAS scores and excellent rates of patients in the observation group were sig- nificantly higher than those in the control group, at 6 months follow up. Differences were signifi- cant between two groups. This may be explained by the fact that rigid fixation limits fibular rota- tion and displacement relative to the tibia and restricts early ankle function training, while non-rigid fixation induces no secondary trauma and allows normal micromotion and dorsal extension of ankle joint, complying with the bio- mechanical environment and achieving physio- logical healing [14]. This finding is consistent with results reported by Degroot et al. [15]. Beumer et al. demonstrated that ankle joints with normal motor function require anteropos- terior, distal, and external rotation of the distal radius to a certain level [16]. In addition, this study showed no statistically significant differ- ences in preoperative age, gender, cause of injury, and fracture classification between the Table 3. Comparison of complication incidence between the two

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Short-Term Outcome of Shelf-Autograft in Uncemented Total Hip Arthroplasty

Short-Term Outcome of Shelf-Autograft in Uncemented Total Hip Arthroplasty

Results: The mean coverage angle by graft was 45.5 ± 7.3% (range: 33 - 72%) and horizontal coverage percentage by graft was 79.3 ± 12.8% (range: 54 - 100%). After a mean follow-up of 26 months (range: 12 - 56 months), no evidence of instability was found in any of these hips. Considering loosening and revision as an end-point, the survival rate was 100%. The patients’ mean Harris hip score (HHS) improved from a mean of 35.50 ± 9.11 preoperatively to 95.10 ± 4.71 at the last follow-up. Rigid fixation of graft to host bone, medial insertion of acetabular cementless cup, and avoidance of lateral or high hip center were found to result in excellent THA with shelf graft outcomes.

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SImmetry&reg Sacroiliac Joint Fusion System with SImmetry Decorticator&reg

SImmetry&reg Sacroiliac Joint Fusion System with SImmetry Decorticator&reg

Pain originating in the SI joint is a highly prevalent and disabling condition. When SI joint disease is positively diagnosed and refractory to conservative care, fusion of the joint is indicated. Open surgical fusion may be ef- fective, yet has major operative risks and morbidities. While minimally invasive SI joint fusion techniques greatly improve upon the disadvantages of open fusion, this typically comes at a cost of minimal joint prepara- tion, resulting in a much smaller fusion mass and increased risk of nonunion. The SImmetry Sacroiliac Joint Fu- sion System builds upon the operative advantages of a minimally invasive approach, with the addition of anin- novative decortication technique that allows preparation of up to 50% of the auricular surface of the SI joint. The decorticated subchondral bone and marrow provide a vascular environment rich in growth factors and me- senchymal stem cells that, when combined with the rigid fixation provided by the threaded implants, create an optimal environment for development of a solid fusion.

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MRI analysis of the ISOBAR TTL internal fixation system for the dynamic fixation of intervertebral discs: a comparison with rigid internal fixation

MRI analysis of the ISOBAR TTL internal fixation system for the dynamic fixation of intervertebral discs: a comparison with rigid internal fixation

DWI is currently the only non-invasive technology to measure in vivo water molecule diffusion, which can re- flect the structural characteristics of tissue. Research shows that the pathogenesis of intervertebral disc degener- ation may be associated with a decrease of the diffusion rate [15,16]. Based on quantitative studies of diffusion of living tissue, DWI may have potential value in the early diagnosis of intervertebral disc degeneration [17,18]. DWI may also allow the non-invasive evaluation of therapeutic efficacy and provide prognostic information in these pa- tients. In DWI, the higher the intervertebral disc water content, the faster the molecular diffusion and the higher the ADC value, reflecting a healthier nucleus pulposus. The lower the intervertebral disc water content, the slower the molecular diffusion, and the lower the ADC value in- dicate a higher degree of degeneration of the intervertebral disc. The purpose of this study was the quantitative evalu- ation of intervertebral disc integrity by evaluating the DWI of the fixed adjacent intervertebral disc. Compared with the preoperative studies, at the 6- and 12-month postoperative evaluations, neither group demonstrated significant changes in ADC values (P < 0.05). However, at 24 months postoperatively, the ADC value was signifi- cantly different (P < 0.05). The ADC values in the ISOBAR TTL group at 6, 12, and 24 months after surgery were higher than those before surgery, which showed that the nucleus pulposus water content postoperatively was increased and that the degree of intervertebral disc de- generation could be slowed or even reversed. In the rigid fixation group, the ADC values were lower than the preoperative value at the 6-, 12-, and 24-month evaluations, indicating that the nucleus pulposus water content of the disc decreased after surgery and that the Table 3 Comparison of preoperative and postoperative ODI values of the two groups of patients ð x s Þ

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Comparative Efficacy and Adaptability of Bioresorbable Plates with Titanium Miniplates in the Management of Mandibular Fractures

Comparative Efficacy and Adaptability of Bioresorbable Plates with Titanium Miniplates in the Management of Mandibular Fractures

Over the past three decades, there has been extensive development of techniques used in the management of cranio- maxillofacial trauma. The most significant advancement related to the management of fractures of mandible is the use of metal plates and screws [1]. These advancements are based on specific technical refinement in the rigid internal fixation methods [2]. The field of oral and maxillofacial surgery had undergone a sea of change from the closed reduction of facial fractures to the non-rigid fixation using metallic wires [3], lag screws [4]. These changes were further replaced by rigid fixation devices using dynamic compression (DCP) and eccentric dynamic compression plates (EDCP) [5]. The evolution of mini plate osteosynthesis had revolutionized the management of facial injuries and had proved to be the right alternative to DCP and EDCP. The metallic mini plates and screws currently in use for cranio maxillofacial fracture, although provide rigid internal bone fixation but have few drawbacks: (1) Once osteosynthesis is achieved, they are no longer needed and they may act as foreign body and create problems in future due to stress-shielding effect [6], (2) they may cause under-lying bone atrophy, [6] (3) interfere with computed tomography (CT) and magnetic resonance imaging (MRI) [7], (4) palpability [8], (5) sensitivity to the extremes of temperature of any oral-intake [8], (6) sometimes exposure of the plate requires removal and second surgery [6] and (7) Growth retardation and intracranial migration have also been documented with metal plates [9].

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Comparison between harvesting and preserving the spinous process for adolescent idiopathic scoliosis

Comparison between harvesting and preserving the spinous process for adolescent idiopathic scoliosis

A high spontaneous fusion rate in early onset scoliosis patients undergoing growth rod exchange surgery has been well documented [17–19]. Extensive extraperiosteal dissection and prolonged immobilization of the instru- ments have been reported to be risk factors for spontan- eous fusion after spinal surgery [19, 20]. Furthermore, pedicle screw-based instrumentation could provide rigid fixation for all three spinal columns, and has shown im- proved coronal curve correction and satisfaction in AIS patients [21–23]. Although AIS patients do not have the same spontaneous fusion ability as those with early onset scoliosis, the potential fusion ability in a skeletally im- mature spine and rigid fixation of pedicle screw instru- mentation may explain why the preserving group achieved a comparably low pseudoarthrosis rate as the harvesting group.

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Biomechanical characteristics of fixation methods for floating pubic symphysis

Biomechanical characteristics of fixation methods for floating pubic symphysis

Depending on the energy level of the trauma, the mortality rate is between 18 and 25% in patients with hemodynamic instability [6]. Therefore, pathophysio- logical and hemodynamic stabilization should be consid- ered carefully before surgical intervention is undertaken. For patients with hemodynamic instability, maneuvers should be performed to decrease pelvic volume and re- duce motion of the bony fragments. The aim of these early damage control techniques is to achieve relative stability in a minimally invasive manner [7–10]. For pa- tients who are hemodynamically stable, early definitive fixation can be undertaken with the goals being good functional recovery and a return to normal life. The purpose of definitive fixation is accurate reduction, rigid fixation, and minimal soft tissue disruption. There are several fixation methods used to treat FPS, including external fixation [11], anterior subcutaneous fixation [10, 12], internal fixation [13], and percutaneous can- nulated screw fixation [14]. To choose the optimal fixation method, it is necessary to study the biomech- anical performance of the different methods.

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Open reduction and internal fixation of extracapsular mandibular condyle fractures: a long-term clinical and radiological follow-up of 25 patients

Open reduction and internal fixation of extracapsular mandibular condyle fractures: a long-term clinical and radiological follow-up of 25 patients

Results: Of the 25 patients, 80% showed occlusion recovery, 88% had no facial nerve injury, and 88% presented good surgical skin scarring. The patients showed early complete recovery of temporomandibular joint functionality and 72% of them were found to be asymptomatic. The postoperative radiographs of all patients indicated good recovery of the anatomical condylar region, and 80% of them had no postoperative complications. The average degree of patient satisfaction was 8.32 out of 10. Our results confirm that the technique of open reduction and internal fixation in association with postoperative functional rehabilitation therapy should be considered for treating patients with extracapsular condylar fractures.

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Genetic Algorithm based Analysis of Rigid and Non Rigid Medical Images

Genetic Algorithm based Analysis of Rigid and Non Rigid Medical Images

partitioning a digital image into multiple segments also known as super pixels. The proposed work mainly relies on the genetic algorithm based concepts. Genetic algorithm is an optimization technique which is performed based on the fitness function criteria. By undergoing maximum number of iterations the result is been obtained. The chromosomal abnormalities can be easily identified with the help of its structure. The chromosomal analysis was performed over the meta-spread chromosome images. Chromosomal overlapping and the touching are the problems in meta- spread image. So the segmentation of the chromosomal structures helps in reducing those abnormalities. The proposed work is to segment the overlapping chromosome images based on the genetic algorithm. The genetic algorithm is an optimization technique that helps in optimizing the energy function which further improves the segmentation accuracy. Due to the non- rigid shape of the chromosome images they can be overlapped or touched with other chromosome images during cell division. Thus for the chromosome analysis the segmentation of overlapping chromosome is required. The regions where the overlapping is more is shown using majority color based on the genetic algorithms worst case, best case and average case concept the best case is identified as the overlapping region in the chromosome image. The mask1 and mask2 are created for the image based on its center and radius .The masks helps in determining the overlapping zones in an image. Finally the cropped image helps in identifying the overlapping regions

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3D Finite Element Analysis of Different Techniques of Rigid Internal Fixation in Mandibular Angle Fractures: An In Vitro study

3D Finite Element Analysis of Different Techniques of Rigid Internal Fixation in Mandibular Angle Fractures: An In Vitro study

to combine information from multiple studies and to compare complication rates for different fixation methods. An English language literature search was conducted for articles on mandibular angle fractures. Information was collected on four variables of interest: compression/noncompression technique, monocortical/bicortical screws, number of plates, and location of plates. Five outcome rates were analyzed: infection, reoperation, hardware removal, malunion, and nonunion. Meta-analyses were run using Comprehensive Meta Analysis, version 2.2.03. Significantly higher rates of infection, reoperation, and hardware removal were found for compression compared with noncompression, two plates compared with one plate, and for plates located on both the inferior and superior borders as compared with superior or inferior only. The results of this meta-analysis found lower complication rates with the use of noncompression, monocortical, and single-plate fixation, supporting the trend toward a single, superiorly placed, monocortical miniplate for fixation of mandibular angle fractures.

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Influence of Subgrade Modulus and Thickness on the Behaviour of Raft Foundation

Influence of Subgrade Modulus and Thickness on the Behaviour of Raft Foundation

Abstract - Analysis of Raft foundation is complex and time consuming as it involves the value of subgrade modulus. The determination of subgrade modulus as illustrated in Indian Standards gives approximate values based on standard penetration test which is unrealistic and it does not explain the procedure for extension of values for larger size plates. The subgrade modulus values will vary over the entire area which makes the soil investigation by plate load test more complex and expensive. Raft is adapted when the soil is poor, and when the soil is poor and the depth of the raft is considerably more, the raft behaves more or less a rigid plate. The soil pressure acting against the slab can be calculated by dividing all the column loads by area of the raft and assuming to be uniformly distributed, instead of going for classical elastic methods like FEM and FDM which is tedious and as it involves the value of modulus of sub- grade reaction. This project involves the study on effect of rigidity of foundation and modulus of subgrade reaction of soil on contact pressure and force quantities.

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Registration of PET and MR hand volumes using Bayesian Networks

Registration of PET and MR hand volumes using Bayesian Networks

Once the tube based model has been fitted to corresponding PET and MR datasets, it is a reasonably simple process to calculate a non-rigid (piecewise rigid) transform between the two data sets. This transform may be used to warp one of the data sets (we warp the PET data) into correspondence with the other. First, a global rigid (translation and rotation) transform is calculated from the corresponding start and end points of the phalange tubes in the two models. The closed form least-squares error minimisation method of Horn is used [12]. Calculating local rigid transformations for each (globally aligned) tube pair is performed using the same method. However, at least three points are required for this method, and only two are available (the start & end of the tube). A third point is generated by using principal components analysis (PCA) to calculate the eigenvector of the globally aligned annotated hand points (both sets) with the smallest eigenvalue. This ‘minor axis vector’ ( V ma ) defines a plane with the

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Fixation and Needle Fixation

Fixation and Needle Fixation

stage of development, the parental other, who helps and encourages the child to recognize its image in the mirror “a third element that can function as a reference point” (Loose, 2002, p. 26). The existence of this reference point, coupled with the idea that the organism is in bits and pieces creates a symbolic matrix that “precipitates the formation of the ‘I’ before this ‘I’ is able to identify with psychically processed sexual drives” Loose, 2002, p.26). This is where the possibility of a relationship with the needle is established and the self-completion it provides in the addicts identity. Addicts quoted by McBride, Pates and Arnold say of the needle: “Without it, life would be unsupportable” (McBride, Pates & Arnold 2007, p. 48). Fraser et al. claim that this fact alone does not warrant the use of the term ‘fixation’. What is required is an unconscious explanation and that is the concern of my thesis. The experience of self-injection, for example, can be explained by appealing to Lacan’s jouissance. This is why it excites both enjoyment and repulsion in the user and the other. Examples of this enjoyment and repulsion can be found in McBride, Pates and Arnold. Self-injectors describe an enjoyment elicited from “self-inflicted pain…they talk as though self-punishment were a pleasure” (McBride, Pates & Arnold 2007, p. 51). Some of Burroughs’ descriptions of injection barely disguise the metaphor with intercourse, ‘Ike’s gentle finger’ and ‘Ike was good.’ The simultaneous existence of enjoyment and repulsion assigns needle fixation to the realm of jouissance.

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Research on Lamina Emergent Mechanisms

Research on Lamina Emergent Mechanisms

As a type of compliant mechanism, Lamina Emergent Mechanisms (LEM) is a mechanical device made of a planar sheet material that can be moved out of the manufacturing plane. By flexibly deforming of the conponents, complex movements can be achieved and are monolithic within each planar layer. The compliant mechanism offers the opportunity to achieve complex. As it can gain motion from the constrained bending of compliant members, complex movements can be achieved with a simple topology. Most of the motion mechanism in nature are compliant, rather than rigid. and the motion comes from the flexing of the compliant member rather than the rigid members that are connected to the hinge, such as the heart, trunk, and bee wings. The smaller the sample, the more likely it is to use the deformation of the compliant member to gain its motion. The same is true of man-made systems. The smaller the device, the greater the advantage of using Compliant mechanism [1] [2].

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