• Journal of KIISE:Software and Applications
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• v.33 no.3
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• pp.335-343
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• 2006

This paper proposes a novel technique of marker-based 2D-3D registration to combine 3D information obtained from preoperative CT images into 2D image obtained from intraoperative x-ray fluoroscopy image. Our method is divided into preoperative and intraoperative procedures. In preoperative procedure, we generate CT-derived DRRs using graphics hardware and detect markers automatically. In intraoperative procedure, we propose a hierarchical two- step registration to reduce a degree of freedom from 6-DOP to 2-DOF which is composed of in-plane registration using principal axis method and out-plane registration using minimal error searching method in spherical coordinate. For experimentation, we use cardiac phantom datasets with confirmation markers and evaluate our method in the aspects of visual inspection, accuracy and processing time. As experimental results, our method keeps accuracy and aligns very fast by reducing real-time computations.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.47 no.5
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• pp.382-387
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• 2021

Objectives: Zygomatic complex (ZMC) fractures comprise up to 40% of all facial fractures. Misaligned bone fragments and misplaced fixation hardware traditionally detected postoperatively on plain radiographs of the skull might require re-operation. The intraoperative O-Arm (Medtronic, USA) is a three-dimensional (3D) computed tomographic imaging system. Materials and Methods: This retrospective single-center study evaluated the utility of O-Arm scanning during corrective surgeries for ZMC and zygomatic arch (ZA) fractures from 2018 to 2020. Three females and 16 males (mean age, 31.52 years; range, 22-48 years) were included. Fracture instability (n=6) and facial deformity (n=15) were the most frequent indications for intraoperative 3D O-Arm scan. Results: The images demonstrated that all fracture lines were properly reduced and fixed. Another scan performed at the end of the fixation or reduction stage, however, revealed suboptimal results in five of the 19 cases, and further reduction and fixation of the fracture lines were required. Conclusion: Implementation of an intraoperative O-Arm system in ZMC and ZA fracture surgeries assists in obtaining predictable and accurate results and obviates the need for revision surgeries. The device should be considered for precise operations such as ZMC fracture repairs.

• Archives of Plastic Surgery
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• v.37 no.1
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• pp.91-94
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• 2010

Purpose: The purpose of this study is to describe the usefulness of intraoperative mobile CT scans in the reduction of zygomatic arch fracture. Method: Two patients with zygomatic arch fractures were selected who were indications of closed reduction by Gilles' approach. After the reduction was done in the operating room with zygomatic arch elevator, intraoperative CT scan was done to check the extent of reduction. Additional reduction was performed according to the obtained images from the intraoperative mobile CT scan. Examination of the preoperative CT, intraoperative CT after the reduction, and postoperative plain X-ray films were done for documentation and analysis. Results: Reduction was carried out successfully to the patients without any complications. Both patients were satisfied with the postoperative cosmetic and functional outcome. Revisional surgery was not necessary during the 6 months follow up. Conclusion: The advantage of this method is that it is easier to obtain three dimensional relationships of the fracture site. Furthermore, the operator is less exposed to radiation hazards compared to other methods that obtain intraoperative images such as the C-arm. In conclusion, intraoperative mobile CT scan can be a useful surgical aid in the reduction of zygomatic arch fractures.

• Journal of Chest Surgery
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• v.26 no.1
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• pp.54-58
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• 1993

Simultaneous bilateral bleb resection was done through bilateral transaxillary thoracotomy in 10 patients with spontaneous pneumothorax during the period from May 1991 to Novemver 1992 in whom bilateral bulla or bleb was detected with using simple chest X-ray and chest CT scanning. To compare the effectiveness of bilateral transaxillary thoracotomy, we investigated 10 unilateral transaxillary thoracotomy patients with spontaneous pneumothorax and two clinical reports from other institutes which dealt the results of bilateral bleb or bulla resection through median sternotomy also. In bilateral transaxillary thoracotomy group,mean operation time was 115 minute,mean intraoperative bleeding was 329 cc, mean postoperative hospital stay was 7.5 days. Postoperative ABGA[Arterial Blood Gas Analysis] was in normal range and postoperative recovery rates of FVC[Forced Vital Capacity], FEV1[Forced Expiratory Volume at 1 second], TV[Tidal Volume] were 84.3%, 93.4%, 88.7%,respectively. In median sternotomy group,mean operation time was 129 minute,mean intraoperative bleeding was 490 cc, mean postoperative hospital stay was 12.4 days. Postoperative ABGA was in normal range and postoperative recovery rates of FVC, FEV1 were 97.3%, 97.4%, respectively. In unilateral transaxillary thoracotomy group, postoperative ABGA was in normal range also and postoperative recovery rates of FVC, FEV1, TV were 91.6%, 99.0%, 96.0%,respectively. In conclusion, simultaneous bilateral bleb resection through bilateral transaxillary thoracotomy should be considered in pneumothorax patients with bilateral bleb or bulla because of cost-effectiveness[reducing hospital days] and better cosmetic result without any impairment in recovery of respiratory function.

• Progress in Medical Physics
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• v.3 no.2
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• pp.1-12
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• 1992

For intraoperative radiation therapy using electron beams, a cone system to deliver a large dose to the tumor during surgical operation and to save the surrounding normal tissue should be developed and dosimetry for the cone system is necessary to find proper X-ray collimator setting as well as to get useful data for clinical use. We developed a docking type of a cone system consisting of two parts made of aluminum: holder and cone. The cones which range from 4cm to 9cm with 1cm step at 100cm SSD of photon beam are 28cm long circular tubular cylinders. The system has two 26cm long holders: one for the cones larger than or equal to 7cm diamter and another for the smaller ones than 7cm. On the side of the holder is an aperture for insertion of a lamp and mirror to observe treatment field. Depth dose curve. dose profile and output factor at dept of dose maximum. and dose distribution in water for each cone size were measured with a p-type silicone detector controlled by a linear scanner for several extra opening of X-ray collimators. For a combination of electron energy and cone size, the opening of the X-ray collimator was caused to the surface dose, depths of dose maximum and 80%, dose profile and output factor. The variation of the output factor was the most remarkable. The output factors of 9MeV electron, as an example, range from 0.637 to 1.549. The opening of X-ray collimators would cause the quantity of scattered electrons coming to the IORT cone system. which in turn would change the dose distribution as well as the output factor. Dosimetry for an IORT cone system is inevitable to minimize uncertainty in the clinical use.

• Korean Journal of Radiology
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• v.22 no.7
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• pp.1124-1131
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• 2021

Objective: To evaluate the feasibility, safety, and effectiveness of CT-guided microcoil localization of solitary pulmonary nodules (SPNs) for guiding video-assisted thoracoscopic surgery (VATS). Materials and Methods: Between June 2016 and October 2019, 454 consecutive patients with 501 SPNs who received CT-guided microcoil localization before VATS in our institution were enrolled. The diameter of the nodules was 0.93 ± 0.49 cm, and the shortest distance from the nodules to the pleura was 1.41 ± 0.95 cm. The distal end of the microcoil was placed less than 1 cm away from the nodule, and the proximal end was placed outside the visceral pleura. VATS was performed under the guidance of implanted microcoils without the aid of intraoperative fluoroscopy. Results: All 501 nodules were marked with microcoils. The time required for microcoil localization was 12.8 ± 5.2 minutes. Microcoil localization-related complications occurred in 179 cases (39.4%). None of the complications required treatment. A total of 463 nodules were successfully resected under the guidance of implanted microcoils. VATS revealed 38 patients with dislocated microcoils, of which 28 underwent wedge resection (21 cases under the guidance of the bleeding points of pleural puncture, 7 cases through palpation), 5 underwent direct lobectomy, and the remaining 5 underwent a conversion to thoracotomy. In 4 cases, a portion of the microcoil remained in the lung parenchyma. Conclusion: CT-guided microcoil localization of SPNs is safe and reliable. Marking the nodule and pleura simultaneously with microcoils can effectively guide the resection of SPNs using VATS without the aid of intraoperative fluoroscopy.

• Journal of Korean Neurosurgical Society
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• v.65 no.1
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• pp.96-106
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• 2022

Objective : The most common complication of anterior cervical discectomy and fusion (ACDF) is cage subsidence and maintenance of disc height affects postoperative clinical outcomes. We considered cage subsidence as an inappropriate indicator for evaluating preservation of disc height. Thus, this study aimed to consider patients with complications such as reduced total disc height compared to that before surgery and evaluate the relevance of several factors before ACDF. Methods : We retrospectively reviewed the medical records of 40 patients who underwent stand-alone single-level ACDF using a polyetheretherketone (PEEK) cage at our institution between January 2012 and December 2018. Our study population comprised 19 male and 21 female patients aged 24-70 years. The minimum follow-up period was 1 year. Twenty-seven patients had preoperative bone mineral density (BMD) data on dual-energy X-ray absorptiometry. Clinical parameters included sex, age, body mass index, smoking history, and prior medical history. Radiologic parameters included the C2-7 cobb angle, segmental angle, sagittal vertical axis, disc height, and total intervertebral height (TIH) at the preoperative and postoperative periods. Cage decrement was defined as the reduction in TIH at the 6-month follow-up compared to preoperative TIH. To evaluate the bone quality, Hounsfield unit (HU) value was calculated in the axial and sagittal images of conventional computed tomography. Results : Lumbar BMD values and cervical HU values were significantly correlated (r=0.733, p<0.001). We divided the patients into two groups based on cage decrement, and 47.5% of the total patients were regarded as cage decrement. There were statistically significant differences in the parameters of measuring the HU value of the vertebra and intraoperative distraction between the two groups. Using these identified factors, we performed a receiver operating characteristic (ROC) curve analysis. Based on the ROC curve, the cut-off point was 530 at the HU value of the upper cortical and cancellous vertebrae (p=0.014; area under the curve [AUC], 0.727; sensitivity, 94.7%; specificity, 42.9%) and 22.41 at intraoperative distraction (p=0.017; AUC, 0.722; sensitivity, 85.7%; specificity, 57.9%). Using this value, we converted these parameters into a bifurcated variable and assessed the multinomial regression analysis to evaluate the risk factors for cage decrement in ACDF. Intraoperative distraction and HU value of the upper vertebral body were independent factors of postoperative subsidence. Conclusion : Insufficient intraoperative distraction and low HU value showed a strong relationship with postoperative intervertebral height reduction following single stand-alone PEEK cage ACDF.

• Journal of Chest Surgery
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• v.37 no.12
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• pp.999-1002
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• 2004

Thirteen year old boy who had been stabbed in his left chest by the knife was transferred to our department from a general hospital, because of the massive bleeding from the intercostal tube drainage. Chest X-ray showed homogeneous density in the left lung field. He was confused and his vital signs were unstable. He was moved into a operating room as soon as possible. After resuscitation, his lacerated left ventricle wound was sutured through median sternotomy. The interventricular shunt was detected with intraoperative transesophageal echocardiography. The traumatic ventricular septal defect was closed via left ventricle using Dacron patch. His postoperative course was uneventful, and he was discharged with small residual shunt.

• Archives of Craniofacial Surgery
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• v.9 no.1
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• pp.12-16
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• 2008

Purpose: Closed reduction is most common treatment method for nasal bone fracture but it requires secondary correction operation commonly. For preventing secondary revision, we applied ultrasonography during closed reduction of nasal bone fracture and examined the result of operation. Methods: 80 patients were sorted into 2 groups, ultrasound-guided closed reduction group(n=40) and manual closed reduction group(n=40). We classified the unilateral fracture involving lower 1/2 of nasal bone into type I, the bilateral fracture involving lower 1/2 of nasal bone into type III and the fracture of upper 1/2 of nasal bone into type III. The occurrence rate of overcorrection and undercorrection were evaluated by comparing preoperative and postoperative MDCT(Multi Direction Computed Tomography). Results: In manual closed reduction group, overcorrection were found in 4 patients and undercorrection were found in 3 patients. In ultrasound-guided closed reduction group, overcorrection was not observed and undercorrection was observed in 2 patients. Conclusion: Intraoperative ultrasound evaluation of nasal bone fracture resulted in reduced occurrence rate of secondary nasal deformities, showed easier detection of the fractured site and have superiority upon simple physical examination or simple x-ray.

• Journal of Chest Surgery
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• v.24 no.4
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• pp.397-403
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• 1991

From June 1987 to January 1991, 24 patients with moderate or massive pericardial effusion underwent subxiphoid pericardial window procedures for diagnosis and therapy. The patients` ages were ranged from 28 years to 71 years. The underlying diseases were chronic renal failure with long term hemodialysis in 3 cases, malignant lung cancer in 7 cases, stomach cancer in 2 cases, tuberculous pericarditis in 5 cases, pyogenic pericarditis in 2 cases, myxedema in one case, one metastatic squamous cell carcinoma from unknown origin and three of undefined etiology. Preoperative diagnoses of pericardial effusions were confirmed by echocardiogram in all cases. Subxiphoid pericardial drainages were performed under general[n=19] or local anesthesia[n=5]. Histological diagnoses were made from the inferior pericardial tissue in all cases except one. In this one case[tuberculous pericarditis], the subxiphoid pericardial approach was failed from intraoperative bleeding. There were two postoperative death, one[in malignant lung cancer] had postoperative ventricular tachycardia which result in cardiac arrest, and the other[unknown origin metastatic malignant effusion] had persistent tachyarrhythmia postoperatively and died on postoperative 5th days. Twenty three patients were followed up from 3 days to 9 months; mean follow-up day was 43 days. The preoperative and postoperative mean cardiothoracic ratio in chest x-ray were 0.69 and 0.52 respectively. Subxiphoid pericardial drainage may provide definitive diagnosis and treatment for pericardial effusions. The approach through subxiphoid pericardium under general or local anesthesia avoids the complications of pericardiocentesis and is effective for malignant pericardial effusion.