• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.20 no.2
• /
• pp.101-105
• /
• 1998

Compound comminuted mandibular fracture is defined as the presence of multiple fracture lines with open wound resulting in many small pieces within the same area. The incidence of mandibular comminution is difficult to determine but reported as 2.7~18.6 % incidence among mandibular fractures. There are controversies in the treatment of mandibular comminuted fractures. Treatment of comminuted mandibular fracture has traditionally involved closed reduction in an effort to avoid stripping periostcum from the bony segments, but rigid internal rigid fixation is used more popular at present. The extent of comminution, displacement of bony fragments and patient general conditions are important factors in decision of the treatment methods. When significant bone displacement is present, it is necessary to reduce these comminuted fragments to an anatomic, pretraumatic relationship to restore facial form and function. In these cases, ORIF allows anantomic reduction of comminuted segments as well as pretraumatic occlusion. Gentle handling of the soft tissue, rigid fixation of bony fragments and adequate immobilization are essential for reducing the complications. This is the report the incidence, causes, complications and treatment of the patients who visited our department for compound comminuted mandibular fractures.

• Journal of Powder Materials
• /
• v.1 no.1
• /
• pp.72-78
• /
• 1994

Two kinds of $U_3Si$ powders and $U_3Si$ dispersed nuclear fuel meats have been prepared by conventional comminution process and a newly developed rotating disk atomization process. In contrast to angular shape and broad size distribution of the conventionally processed powder, the atomized powder was spherical and showed narrow size distribution. For the atomized powder, the heat treatment time for the formation of $U_3Si$ by a peritectoid reaction was reduced to about one tenth, thanks to microstructure refinement by rapid cooling of about 5$\times$104 K/s. The extruding pressure of atomized $U_3Si$ powder and Al powder mixture was lower than that of comminuted $U_3Si$ and Al powder mixture. The elongation of the atomization processed fuel meats was much higher than that of the comminution processed fuel meats and remained over 10% up to 80wt.% of $U_3Si$ powder fraction in the fuel meats. It appears therefore that the loading density of $U_3Si$ in fuel meat can be increased by using atomized $U_3Si$ powder. The atomized spherical particles were randomly distributed, while the comminuted particles with angular and longish shape were considerably aligned along the extrusion direction. Along the transverse direction of the extraction the electrical conductivity of the atomization processed fuel meats was appreciably higher than that of comminution processed fuel meats. This tendency became pronounced as $U_3Si$ content increased. Because the thermal conduction which is believed to be proportioned to the electrical conduction in the nuclear fuel meats occurs in radial direction, the atomization processed fuel can be better used in research reactors where high thermal conductivity is required.

• Clinics in Shoulder and Elbow
• /
• v.17 no.1
• /
• pp.10-17
• /
• 2014

Background: The aim of this study was to assess the clinical outcomes after treatment of proximal humeral fractures with locking plates, and to determine which factors influence the clinical and radiological outcomes. Methods: Fifty six patients who were treated with locking plates for proximal humeral fractures and had been followed for more than 1 year were enrolled in this study. We performed functional evaluation using the Constant score and analyzed radiographic results. The following factors that may potentially influence the clinical outcomes were assessed: age, gender, type of fracture, presence of medial metaphyseal comminution, bone mineral density, anatomical reduction, restoration of medial mechanical support, and postoperative complications. Results: The mean Constant score was 70.1 points at the final follow-up. Female gender, 4-part fractures, AO type-C fractures, and fractures with medial metaphyseal comminution were associated with a poor clinical outcome. On the other hand, restoration of medial mechanical support and accurate anatomical reduction had a positive influence on clinical outcomes. Postoperative complications resulted in 3 patients (intra-articular screw perforation: 1 patient, varus deformity with screw loosening: 1 patient, nonunion: 1 patient). Conclusions: When treating proximal humeral fractures with locking plate fixation, following factors: a female gender, Neer type 4-part fracture, AO type C fracture, and medial metaphyseal comminution are important risk factors that surgeons should take into consideration. Factors that contribute to better clinical outcomes of operative treatment for humeral fractures are accurate anatomical reduction and restoration of medial mechanical support.

• Resources Recycling
• /
• v.29 no.2
• /
• pp.28-36
• /
• 2020

To enhance the recycling rate of wasted glass bottles toward recycled aggregates, the study would decide optimal comminution equipment based on the particle size distribution, aspect ratio and equipment energy analysis. The impact, compress and abrasion is type of generated force by comminution. So, hammer crusher, shredder, roll crusher and ball mill have been selected because they have characteristic which is each type of force. As a result of the particle size analysis of each product, only the shredder product satisfied concrete and asphalt aggregate quality standard condition. Also, as a result of aspect ratio analysis using Imaging software program (Image J, National institute of health), most of size fraction is confirmed under 1.6 value. It was confirmed that the product has low dangerousness and satisfying to shpage index. Also, the particle reduction ratio against input energy of shredder product was the most high. Therefore, we can decide that the optimal equipment which applicable for comminuting waste glass bottle in certain particle size under 10mm is shredder. The result of study will make contribution to increasing energy efficiency of comminution processing and competitiveness of product.

• 한국연소학회:학술대회논문집
• /
• 2002.06a
• /
• pp.247-251
• /
• 2002

• Clinics in Shoulder and Elbow
• /
• v.20 no.1
• /
• pp.49-56
• /
• 2017

Since the olecranon fractures are caused by relatively low-energy injuries, such as a fall from standing height, they are usually found without comminution. Less commonly they can be developed by high-energy injuries and have severe concomitant comminution or injuries to surrounding structures of the elbow. Because the fracture by nature is intra-articular with the exception of some avulsion-type fracture, a majority of olecranon fractures are usually indicated for surgical treatment. Even if there is minimal displacement, surgical treatment is recommended because there is a possibility of further displacement by the traction force of triceps tendon. The most common type of olecranon fracture is displaced, simple non-comminuted fracture (that is, Mayo type IIA fractures). Although tension band wiring was the most widespread treatment method for these fractures previously, there is some trends toward fixation using locking plates. Primary goal of the surgery is to restore a congruent joint and extensor mechanisms by accurate reduction and stable fixation so that range of motion exercises can be performed. The literature has shown that good clinical outcomes are achieved irrespective of surgical fixation technique. However, since the soft tissue envelope around the elbow is poor and the implants are located at the subcutaneous layer, implant irritation is still the most common complication associated with surgical treatment.

• Journal of the Korean Orthopaedic Association
• /
• v.56 no.2
• /
• pp.150-156
• /
• 2021

Purpose: To determine how the location, displacement, intra-articular involvement, comminution of a 5th metatarsal base fracture affect results of early weight-bearing treatment. Materials and Methods: From January 2013 to July 2017, 34 cases of 34 patients diagnosed with a fracture of the zone I and II 5th metatarsal base were enrolled. The mean follow-up period was 13 months (6-15 months). One patient was excluded as a refracture during the follow-up period, and 33 patients underwent conservative treatment. Anteroposterior, lateral, and simple oblique radiography and computed tomography of the foot were performed to evaluate the location and displacement of the fracture, the degree of joint involvement, and comminution. In all 33 patients, a short leg cast or boot brace was selected immediately after the injury, tolerable weight bearing was allowed. If the pain disappeared, full weight bearing was performed after wearing a plain shoe or postoperative shoe. As a clinical result, the American Orthopedic Foot and Ankle Society (AOFAS) score was evaluated at the final follow-up. During outpatient follow-up, a simple radiograph of the foot was taken to confirm the time of radiological bone union and return to work. Results: Nine males and 24 females, with an average age of 48.7 years, were enrolled in the study. Twenty-four patients had zone I fractures, and nine patients had zone II fractures. Twenty-two out of 33 patients had a fracture displacement of 2 mm or more. Nine and five patients had joint involvement and comminution, respectively. There was a statistically significant return to work from zone I to zone II. The AOFAS score was excellent at the final follow-up and there was no significant difference. When classifying and comparing the degree of fracture displacement, joint involvement, and comminution, there were no significant differences in the radiological union time and return to work. In all cases, satisfactory results were obtained at the final follow-up. Conclusion: Satisfactory clinical results can be obtained by allowing early weight-bearing regardless of the fracture location, displacement, joint involvement, or comminution in zone I and II 5th metatarsal base fractures.

• The Journal of Engineering Geology
• /
• v.20 no.2
• /
• pp.183-189
• /
• 2010

Fault gouge samples were collected from the fault cores of the boundary faults between the Cretaceous Basement and the Tertiary Waeup Basin. Fractal dimensions (D) were obtained by using survivor grains which were analysed from six thin sections of the gouges under the optical microscope. The elliptical survivor grains show a shape preferred orientation almost parallel to clay foliation in matrix, suggesting that it was formed by the rotation of the survivor grains in abundant fine-grained matrix during repeated fault slips. The size distributions of the survivor grains follow power-laws with fractal dimensions in the 2.40-3.02 range. D values of all samples but one are higher than a specific D value equal to 2.58 which predicts the self similarity of fragmentation process in constrained comminution model (Sammis et al., 1987), which indicates large fault slip and multiple faulting. Probably the higher D values than 2.58 mean the non-self-similar evolution of cataclastic rocks where fragmentation mechanism changed from constrained comminution to the grain abrasion accompanying selective fracture of larger grains.

• Journal of the Korean Orthopaedic Association
• /
• v.56 no.4
• /
• pp.326-333
• /
• 2021

Purpose: A retrograde intramedullary nail is commonly used to treat femoral shaft and distal femur fractures. The authors analyzed the treatment results and the factors affecting the period of bone union for thirty-five patients treated with a retrograde intramedullary nail. Materials and Methods: Thirty-five patients who could be followed up for more than twelve months after the treatment with retrograde intramedullary nailing were analyzed retrospectively. The treatment results and the relationship between the period of bone union and the patient's age, sex, comminution of fracture, presence of open fracture, location of the fracture, and accompanying fractures were evaluated. Results: The average bone union time was 4.50 months. The period of bone union was unaffected by the age, sex, location, and presence of open fractures but was affected by the presence of comminution and accompanying fractures. Conclusion: Retrograde intramedullary nailing is effective for distal and shaft of fractures of the femur. The period of bone union is affected by the presence of comminution and accompanying fractures.

• Journal of Korean Foot and Ankle Society
• /
• v.17 no.2
• /
• pp.154-160
• /
• 2013

The treatment of open, traumatic intraarticular injuries to the metatarsophalangeal joint with severe articular comminution and cartilage defect of metatarsal head is a challenge to the foot surgeon. We report the joint reconstruction treating the injured joint by autogenic costal osteochondral graft with satisfactory outcome.