• Journal of Korean Neurosurgical Society
• /
• v.53 no.4
• /
• pp.235-240
• /
• 2013

Fusiform aneurysms on the basilar artery (BA) trunk are rare. The microsurgical management of these aneurysms is difficult because of their deep location, dense collection of vital cranial nerves, and perforating arteries to the brain stem. Endovascular treatment is relatively easier and safer compared with microsurgical treatment. Selective occlusion of the aneurysmal sac with preservation of the parent artery is the endovascular treatment of choice. But, some cases, particularly giant or fusiform aneurysms, are unsuitable for selective sac occlusion. Therefore, endovascular coiling of the aneurysm with parent vessel occlusion is an alternative treatment option. In this situation, it is important to determine whether a patient can tolerate parent vessel occlusion without developing neurological deficits. We report a rare case of fusiform aneurysms in the BA trunk. An 18-year-old female suffered a headache for 2 weeks. Computed tomography and magnetic resonance image revealed a fusiform aneurysm of the lower basilar artery trunk. Digital subtraction angiography revealed a $7.1{\times}11.0$ mm-sized fusiform aneurysm located between vertebrovasilar junction and the anterior inferior cerebellar arteries. We had good clinical result using endovascular coiling of unruptured fusiform aneurysm on the lower BA trunk with parent vessel occlusion after confirming the tolerance of the patient by balloon test occlusion with induced hypotension and accompanied by neurophysiologic monitoring, transcranial Doppler and single photon emission computed tomography. In this study, we discuss the importance of preoperative meticulous studies for avoidance of delayed neurological deficit in the patient with fusiform aneurysm on lower basilar trunk.

• Steel and Composite Structures
• /
• v.28 no.5
• /
• pp.617-628
• /
• 2018

Steel shear wall possesses priority over many of the current lateral load-bearing systems due to reasons like higher elastic stiffness, desirable ductility and energy absorption, convenience in construction and implementation technology, and economic criteria. Besides these advantages, this system causes increase in the dimensions of other structural elements due to its high stiffness as one of its intrinsic characteristics. One of the methods for stiffness reduction is perforating the wall panel and creating openings in the wall that can also be used as windows or ducts in buildings service period. The aim of the present study is probing the appropriate geometric shape and location of opening to fulfil economic criterion plus technical and seismic design criteria. In the present research, a number of possible while reasonable opening shapes and locations are defined in various sizes for some steel shear wall specimens. The specimens are modelled in ABAQUS finite elements software and analyzed using nonlinear pushover analysis. Finally, the analyses' results are reported as force-displacement diagrams and the strength, the initial stiffness and the energy absorption are calculated for all specimens and compared together. The obtained results show that both shape and location of the openings affect the seismic parameters of the shear wall. The specimens in which the openings are further from the center and closer to the columns possess higher stiffness and strength while the specimens in which the openings are closer to the center show more considerable changes in their seismic parameters in response to increase in opening area.

• Structural Engineering and Mechanics
• /
• v.68 no.2
• /
• pp.261-275
• /
• 2018

A comprehensive study was provided to investigate the buckling behavior of the steel plates with and without through-thickness holes subjected to uniaxial compression using ABAQUS. The method was validated by the results reported in the literature. Using the critical stresses, the buckling coefficients ($K_c$) were calculated. The effects of inclusion of material nonlinearity, plate thickness (t), aspect ratio (AR), and initial imperfection on buckling resistance of the plate was studied. Besides, the effects of having the hole in the plate were also studied. The diameter of the hole was normalized by dividing by plate breadth and was given in the form of ${\alpha}$. Results showed that perforating one hole in the center of a plate increases the plate buckling resistance while the having two holes resulted in a decrease in the plate buckling resistance. The effects of hole eccentricity (Ecc) on the buckling resistance of the plate was studied. The position of the hole center was normalized by half of the plate breadth and length in X- and Y-directions, respectively. In this study, four cases of boundary conditions were considered, and the corresponding buckling behavior were studied combined with plate aspect ratio. It was observed that the boundary condition of the case I resulted in the highest buckling resistance. Finally, a comparison was made between the buckling behavior of the uniaxially and biaxially loaded plate. It was revealed that the buckling resistance of a biaxially loaded plate is lower half than half of that of the uniaxially loaded plate.

• Geomechanics and Engineering
• /
• v.5 no.5
• /
• pp.463-483
• /
• 2013

Considering the influences of fluid penetration, casing, excavation processes of wellbore and perforation tunnels, the seepage-deformation finite element model of oil and gas well coupled with perforating technique is established using the tensile strength failure criterion, in which the user-defined subroutine is developed to investigate the dynamic evolvement of the reservoir porosity and permeability. The results show that the increases of perforation angle and decreases of perforation density lead to a higher fracture initiation pressure, while the changes of the perforation diameter and length have no evident influences on the fracture initiation pressure. As for initiation location for the fracture in wellbore, it is on the wellbore face while considering the presence of the casing. By contrast, the fractures firstly initiate on the root of the tunnels without considering casing. Besides, the initial fracture position is also related with the perforation angle. The fracture initiation position is located in the point far away from the wellbore face, when the perforation angle is around $30^{\circ}$; however, when the perforation angle is increased to $45^{\circ}$, a plane fracture is initiated from the wellbore face in the maximum horizontal stress direction; no fractures was found around perforation tunnels, when the angel is close to $90^{\circ}$. The results have been successfully applied in an oilfield, with the error of only 1.1% comparing the fracture initiation pressure simulated with the one from on-site experiment.

• Archives of Plastic Surgery
• /
• v.40 no.6
• /
• pp.761-765
• /
• 2013

Background Partially resecting ribs of the recipient site to facilitate easy anastomosis of the internal mammary vessels to free flaps during breast reconstruction can cause chest wall pain or deformities. To avoid this, the intercostal perforating branches of the internal mammary vessels can be used for anastomosis. The purpose of this study was to investigate the location and size of the internal mammary perforator vessels based on clinical intraoperative findings and to determine their reliability as recipient vessels for breast reconstruction with microsurgical free tissue transfer. Methods Twelve patients were preoperatively screened for the presence of internal mammary perforators using Doppler tracing. After modified radical mastectomy was performed by a general surgeon, the location and size of the internal mammary perforator vessels were microscopically investigated. The external diameter was examined using a vessel-measuring gauge from a mechanical coupling device, and the distance from the mid-sternal line to the perforator was also measured. Results The largest arterial perforator averaged 1.5 mm, and the largest venous perforator averaged 2.2 mm. Perforators emerging from the second intercostal space had the largest average external diameter; the second intercostal space also had the largest number of perforators arising from it. The average distance from the mid-sternal line to the perforator was 20.2 mm. Conclusions Internal mammary perforators presented consistent and reliable anatomy in this study. Based on these results, the internal mammary perforators appear to have a suitable diameter for microvascular anastomosis and should be considered as an alternative recipient vessel to the internal mammary vessel.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.35 no.3
• /
• pp.200-209
• /
• 2013

Over the past few years, a large number of perforator flaps have been revised by several microsurgeons in the USA, France, Canada and Japan. A perforator flap is a flap of skin or subcutaneous tissue that is based on the dissection of a perforating vessel, which is a perforator. In short, a perforator is a vessel that has its origin in one of the axial vessels of the human body. By reducing any muscle harvesting and trauma to a minimum, perforator flaps aim to minimize donor site morbidity, and by avoiding the transfer of dennervated muscle, the long-term bulk of the free tissue transfer becomes more predictable. There are a finite number of potential perforator flaps in the body, which are based on the named source arteries. The most commonly used perforator flaps are deep inferior epigastric perforator, superior gluteal artery perforator, thoraco dorsal artery perforator, medial sural artery perforator, and anterolateral thigh perforator flap. For a better understanding of perforators as a routine reconstructive procedure in oral and maxillofacial surgery, the definition with nomenclature, classifications with special characteristics, and review points for their individual applications must be learned and memorized by the young doctors in the course regarding the special curriculum periods for the Korean national board of oral and maxillofacial surgery. Perforator flaps have been known to have many advantages, so this review article summarized their applications to the maxillofacial reconstruction in the Korean language.

• Archives of Plastic Surgery
• /
• v.34 no.3
• /
• pp.352-357
• /
• 2007

Purpose: The coverage of distal soft tissue defects and bony exposure of the lower extremity has long been recognized to be difficult clinical problem. Covering with a local skin flap is usually impractical because of the extensive and deep crush, hence free flap has been used commonly for the coverage of the wound. Although it can provide good results, it has many disadvantages. Designing an adipofascial flap raised on perforating vessels of the posterior tibia artery is a reliable and simple method to perform, and it can solve these problems. Methods: From May 2005 to May 2006, 8 patients underwent reconstruction of lower leg defects utilizing various type of the posterior tibial artery perforator adipofascial flaps. The flap provided a durable and thin coverage for the defect, as well as a well vascularized bed for skin grafting. Results: The flap size ranged $15-80cm^2$, and skin graft was done for the recipient site. The flap were successfully used for the lower extremity reconstruction in most cases. Minor complications occurred in 4 cases. There was no functional disability of the donor site with esthetically pleasing results. Furthermore, these flaps were both easy to raise and insured sufficient arterial blood supply. Conclusion: We believe there are many advantages to this posterior tibial artery perforator adipofascial flap and that it can be highly competitive to the free flaps in the lower extremity reconstruction.

• Journal of Chest Surgery
• /
• v.38 no.7 s.252
• /
• pp.504-506
• /
• 2005

Intracavitary coronary artery is variant anomalous entrance to right ventricular cavity of left anterior descending artery. Since the disease is extremely rare, there has not been any report of it in Korea and is only found in $0.2\~0.3\%$ of all CABG patients. It is very difficult to be diagnosed by preoperative coronary arteriography (CAG) and secure suture is needed for right ventriculotomy after CABG due to bleeding from right ventricle. Horizontal mattress suture with pledget has been recommended but, it could compress the myocardium surrounding ventriculotomy and result in disturbed flow of left anterior descending artery branch and perforating artery. So we used simple interrupted suture and the patient was recovered as other CABG patients without complications.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.36 no.12
• /
• pp.1577-1583
• /
• 2012

Penetrator with enhanced lateral effect (PELE) is a novel projectile that does not require dynamite and a fuse. It comprises a high-density jacket that is closed at its rear end and filled with a low-density filling material. To study the explosion characteristics of PELE using AUTODYN-3D code, the calculation models of the projectile body and the bullet target were developed and the process of penetrating an aluminum-2024 alloy target using PELE was simulated. The scattering characteristics after PELE penetrated the aluminum-2024 alloy target were studied for different filling materials. The explicit finite element analysis of PELE fragmentation was implemented with the stochastic failure criterion in AUTODYN-3D code. As the filling expanded, the fragments gained velocity and dispersed laterally, increasing the damage area considerably. The number and shape of PELE fragments differed depending on the impact pressure of the filling that fragmented during the penetration and lateral dispersion processes.

• Archives of Plastic Surgery
• /
• v.39 no.4
• /
• pp.354-359
• /
• 2012

Background During the planning of a thoracodorsal artery perforator (TDAP) free flap, preoperative multidetector-row computed tomographic (MDCT) angiography is valuable for predicting the locations of perforators. However, CT-based perforator mapping of the thoracodorsal artery is not easy because of its small diameter. Thus, we evaluated 1-mm-thick MDCT images in multiple planes to search for reliable perforators accurately. Methods Between July 2010 and October 2011, 19 consecutive patients (13 males, 6 females) who underwent MDCT prior to TDAP free flap operations were enrolled in this study. Patients ranged in age from 10 to 75 years (mean, 39.3 years). MDCT images were acquired at a thickness of 1 mm in the axial, coronal, and sagittal planes. Results The thoracodorsal artery perforators were detected in all 19 cases. The reliable perforators originating from the descending branch were found in 14 cases, of which 6 had transverse branches. The former were well identified in the coronal view, and the latter in the axial view. The location of the most reliable perforators on MDCT images corresponded well with the surgical findings. Conclusions Though MDCT has been widely used in performing the abdominal perforator free flap for detecting reliable perforating vessels, it is not popular in the TDAP free flap. The results of this study suggest that multiple planes of MDCT may increase the probability of detecting the most reliable perforators, along with decreasing the probability of missing available vessels.