Posterior Cervical Spine Crisscross Fixation: Biomechanical Evaluation

Background Biomechanical/anatomic limitations may limit the successful implantation, maintenance, and risk acceptance of posterior cervical plate/rod fixation for one stage decompression-fusion. A method of posterior fixation (crisscross) that resolves biomechanical deficiencies of previous facet wiring techniques and not reliant upon screw implantation has been devised. The biomechanical performance of the new method of facet fixation was compared to the traditional lateral mass plate/screw fixation method. Methods Thirteen human cadaver spine segments (C2-T1) were tested under flexion-compression loading and four were evaluated additionally under pure-moment load. Preparations were evaluated in a sequence of surgical alterations with intact, laminectomy, lateral mass plate/screw fixation, and crisscross facet fixation using forces, displacements and kinematics. Findings Combined loading demonstrated significantly lower bending stiffness (p \u3c 0.05) between laminectomy compared to crisscross and lateral mass plate/screw preparations. Crisscross fixation showed a comparative tendency for increased stiffness. The increased overall motion induced by laminectomy was resolved by both fixation techniques, with crisscross fixation demonstrating a comparatively more uniform change in segmental motions. Interpretation The crisscross technique of facet fixation offers immediate mechanical stability with resolution of increased flexural rotations induced by multi-level laminectomy. Many of the anatomic limitations and potentially deleterious variables that may be associated with multi-level screw fixation are not associated with facet wire passage, and the subsequent fixation using a pattern of wire connection crossing each facet joint exhibits a comparatively more uniform load distribution. Crisscross wire fixation is a valuable addition to the surgical armamentarium for extensive posterior cervical single-stage decompression-fixation

Short Term Analysis of various uses of Cancellous Femoral Head and Cortical Allografts and their functional outcome in Orthopaedic Surgery

INTRODUCTION: Autografting has many disadvantages such as additional blood loss, increased operative time and cutaneous nerve damage, persistent pain at the donor site, vascular injury, and iliac bone fracture, herniation into the defect and in additional morbidity. Also the amount of morbidity is in direct proportion to the quality of graft retried. When the graft requirement is larger as in children where risk of damage to growth plate is high, revision hip surgeries, traumatic bone defects, spiral fusion and decompression surgeries, allograft comes into play. Although technique for allograft bone storage was described in the late 1940s and whole segmental grafts were used for tumor surgery in 1960s, the use of femoral head allografts as structural bone grafts was started in 1976 for revision hip surgeries. Initially, bone grafting was performed most commonly during complex primary hip arthroplasties such as for dysplasia, Protrusio acetebuli etc; currently for revision hip arthroplasty, foot and ankle surgeries, tumors and fracture non unions. The technique and practice of bone allografting in India is yet to take a firm footing. The facility for proper processing of the harvested bone allografts, its storage and strict donor screening is available only at few tertiary heath centers in India. The bone bank in government General Hospital started in the year 2005 is one such place aimed at maximal utilization of the allografts. AIM: 1. To analyze various the uses cancellous and cortical allografts in orthopaedic surgery. 2. The functional outcome of the allografts in these conditions. MATERIALS AND METHODS: Between February 2003-October 2006, 38 cases of cortical and cancellous allografting has been carried out at the department of orthopaedics, Govt. General Hospital, Chennai. This was a prospective study conducted in 38 patients, 22 of which were males and 16 were females. The Age groups of these patients were ranging from 6-55 years. Benign bone tumors were 21 cases of which the histopathological diagnosis was Fibrous dysplasia in 7 cases, Giant cell tumor in 4 cases, ABC in 2 cases, Chondroblastoma in 2 cases, Chondromyxoid fibroma in 1 case, Simple bone cyst in 2 cases, Osteochondroma with fracture in 2 cases and Chondroma 1 case. RESULTS: None of the patients developed systemic infection this highlights the fact that a through donor screening, proper allograft processing and storage was as essential as operative planning and technique for successful outcome of the procedure. Although the short term results were encouraging, it is required to study these cases for longer periods to reach a conclusion about the state of incorporation of structural bone allografts and need for re – surgery at a longer follow up. CONCLUSION: 1. Bone allograft is a safe and reliable adjuvant in the management of bone defect in the setting of tumors and traumatic bone loss, and revision hip surgeries and spine surgeries. 2. Better results are observed with use of both morsellized and structural bone allografts clinically as well as radiologically. 3. Allograft procured and processed in sterile condition and stringent donor screening are very important safe guards for prevention of disease transmission. 4. Autoclaving though weakens the graft, reduces the immunological as well as reduces further, the risk of disease transmission without much comparative on bony union. 5. Cancellous femoral heads are an excellent method in the management of bone tumor defects. 6. Femoral head allografts are available options in traumatic bone defects and in children. 7. Cortical allografts and autografts add additional sterility to the defect. 8. The clinical results are good and support recommendations for continued use the grafts and development of the technique

Public perception towards homeopathy in Tamil Nadu, India

675-681In recent scenario one of the rapidly growing systems of medicine and is being practiced almost all over the world. Consumer perception clear as the method of consumer frequently view or sense the about certain the products and services. In the objectives of this research aims at de-constructing the awareness and perception of homeopathy, from the point of view of its general public and the need for the study, determination help the general public and society to have a look at future prospects of the public. Non-probability convenience sampling was used to collect responses. Finally, 60 sample questionnaires used for data analysis purposes. In this research carried out to investigate whether homeopathy put into practice has reached the public and their perception regarding homeopathy medicines. The media has campaigns that should restrain interviews of homeopathy remedies and the results are finished successful trials. The government ought to create further awareness of conventional medicines toward the public and it is extremely important to the feature

Public perception towards homeopathy in Tamil Nadu, India

In recent scenario one of the rapidly growing systems of medicine and is being practiced almost all over the world. Consumer perception clear as the method of consumer frequently view or sense the about certain the products and services. In the objectives of this research aims at de-constructing the awareness and perception of homeopathy, from the point of view of its general public and the need for the study, determination help the general public and society to have a look at future prospects of the public. Non-probability convenience sampling was used to collect responses. Finally, 60 sample questionnaires used for data analysis purposes. In this research carried out to investigate whether homeopathy put into practice has reached the public and their perception regarding homeopathy medicines. The media has campaigns that should restrain interviews of homeopathy remedies and the results are finished successful trials. The government ought to create further awareness of conventional medicines toward the public and it is extremely important to the feature

Biomechanical Tolerance of Whole Lumbar Spines in Straightened Posture Subjected to Axial Acceleration

Quantification of biomechanical tolerance is necessary for injury prediction and protection of vehicular occupants. This study experimentally quantified lumbar spine axial tolerance during accelerative environments simulating a variety of military and civilian scenarios. Intact human lumbar spines (T12‐L5) were dynamically loaded using a custom‐built drop tower. Twenty‐three specimens were tested at sub‐failure and failure levels consisting of peak axial forces between 2.6 and 7.9 kN and corresponding peak accelerations between 7 and 57 g. Military aircraft ejection and helicopter crashes fall within these high axial acceleration ranges. Testing was stopped following injury detection. Both peak force and acceleration were significant (p \u3c 0.0001) injury predictors. Injury probability curves using parametric survival analysis were created for peak acceleration and peak force. Fifty‐percent probability of injury (95%CI) for force and acceleration were 4.5 (3.9–5.2 kN), and 16 (13–19 g). A majority of injuries affected the L1 spinal level. Peak axial forces and accelerations were greater for specimens that sustained multiple injuries or injuries at L2–L5 spinal levels. In general, force‐based tolerance was consistent with previous shorter‐segment lumbar spine testing (3–5 vertebrae), although studies incorporating isolated vertebral bodies reported higher tolerance attributable to a different injury mechanism involving structural failure of the cortical shell. This study identified novel outcomes with regard to injury patterns, wherein more violent exposures produced more injuries in the caudal lumbar spine. This caudal migration was likely attributable to increased injury tolerance at lower lumbar spinal levels and a faster inertial mass recruitment process for high rate load application. Published 2017. This article is a U.S. Government work and is in the public domain in the USA

Mechanisms of Cervical Spine Disc Injury under Cyclic Loading

Study Design Determination of human cervical spine disc response under cyclic loading. Purpose To explain the potential mechanisms of intervertebral disc injury caused by cyclic loading. Overview of Literature Certain occupational environments in civilian and military populations may affect the cervical spine of individuals by cyclic loading. Research on this mechanism is scarce. Methods Here, we developed a finite element model of the human C4–C5 disc. It comprised endplates, five layers of fibers, a nucleus, and an annulus ground substance. The endplates, ground substance, and annular fibers were modeled with elastic, hyperviscoelastic, and hyper-elastic materials, respectively. We subjected the disc to compressive loading (150 N) for 10,000 cycles at frequencies of 2 Hz (low) and 4 Hz (high). We measured disc displacements over the entire loading period. We obtained maximum and minimum principal stress and strain and von Mises stress distributions at both frequencies for all components. Further, we used contours to infer potential mechanisms of internal load transfer within the disc components. Results The points of the model disc displacement versus the loading cycles were within the experimental corridors for both frequencies. The principal stresses were higher in the ground matrix, maximum stress was higher in the anterior and posterior annular regions, and minimum stress was higher along the superior and inferior peripheries. The maximum principal strains were radially directed, whereas the minimum principal strains were axially/obliquely directed. The stresses in the fibers were greater and concentrated in the posterolateral regions in the innermost layer. Conclusions Disc displacement was lower at high frequency, thus exhibiting strain rate stiffening and explaining stress accumulation at superior and interior peripheries. Greater stresses and strains at the boundaries explain disc injuries, such as delamination. The greater development of stresses in the innermost annular fiber layer (migrating toward the posterolateral regions) explains disc prolapse

Investigation on wear and corrosion behavior of equal channel angular pressed aluminium 2014 alloy

Aluminium 2014 alloy solutionized at 495°C, aged at 195°C was subjected to Equal Channel Angular Pressing (ECAP). Dry sliding wear tests were conducted using pin on disc tribometer system under nominal loads of 10N and 30N with constant speed 2m/s for 2000m in order to investigate their wear behavior after ECAP. The Co-efficient of friction and loss in volume were decreased after ECAP. The dominant wear mechanism observed was adhesion, delamination in addition to these wear mechanisms, oxidation and transfer of Fe from the counter surface to the Al 2014 pin were observed at higher loading condition. The corrosion behavior was evaluated by potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) in 3.5% NaCl solution. The results obtained from PDP showed higher corrosion potential and lower corrosion density after ECAP than base. Electrochemical impedance spectroscopy (EIS) showed higher charge transfer resistance after ECAP. Surface morphology showed decreased pit size and increased oxygen content in ECAP sample than base after PDP

Effect of Head Restraint Position on Neck Injury Criteria in Rear Impact

ABSTRACT The objective of this study was to determine the forces and bending moments at the top of the Hybrid III dummy neck secondary to rear impact acceleration and evaluate the various proposed injury criteria. Rear impact sled tests were conducted by applying the Federal Motor Vehicle Safety Standards FMVSS 202 acceleration pulse. Differing positions of the head restraint in terms of height (750 and 800 mm) and backset (zero, 50, and 100 mm) were used to determine the axial and shear forces, bending moments, and injury criteria (NIC, N ij , and N km ). The time sequence of attainment of these parameters was determined along with peak values

Suitability of current side impact test dummies in far-side impacts

This study set out to compare the suitability of five current side impact test dummies to simulate that of a 50th percentile Post Mortem Human Subject (PMHS) in a far side impact crash configuration. A number of comparative crash tests were undertaken, involving a 50% PMILS and four current side impact crash test dummies (BioSIO, a BioSID with a lumbar spine modification, EuroSID, and WorldSIU) using the ECE95 test procedure at 65km/h. Crash test data were collected from full -scale crash tests conducted using a Holden Commodore: fitted with a 50% Post Mortem Human Subject (PMHS) and a BioSID and WorldSID test dummy in the driver seat. Additional crash test data were obtained using a similar full-scale validated sled test setup. The results demonstrate that the current WorldSID prototype and a BioSID dummy with a modified lumbar spine unit can provide reasonable simulations of occupant kinematics and injuries to help advance vehicle countermeasures. Further work is required to test the robustness and generality of these findings for improved far-side impact protection