• Journal of Korea Multimedia Society
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• v.21 no.6
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• pp.678-684
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• 2018

In order to broaden the indication of middle ear implant, research has been actively conducted on the reverse output method that stimulates the round window. However, it is very difficult to transmit the vibration output effectively because the indivisual anatomical difference of the round window niche is very large and also the visual field is not secured even by a skilled otolaryngologic surgeon. In this paper, we propose a new reverse stimulation method of middle ear implants that transmits energy to the inner ear by using air as a medium. This can compensate for the disadvantages of the conventional method of transmitting vibration energy and minimizes the energy transfer efficiency interference due to the combination of the excitation point and the output device. It was shown that forward and backward transfer characteristics were obtained by cadaveric experiments, and it was shown that it can overcome the acoustical impedance of high round window and transmit energy to inner ear. The receiver, which is the output device of the conventional hearing aids, can generate a constant volume velocity, so it can have a high output at a limited volume, such as a round window niche. So, suggested method can overcome the high acoustical impedance of the round window and deliver acoustic energy to the inner ear.

• Journal of Korean Neurosurgical Society
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• v.40 no.5
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• pp.357-362
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• 2006

Objective : The incidence of aneurysmal subarachnoid hemorrhage has been increasing. At the same time, surgical results for elderly patients are unsatisfactory and no guidelines of treatment are available. We carried out a study comparing variable factors and surgical results between young and old age groups to find ways to improve prognosis. Methods : A retrospective study was carried out on 754 patients who were operated on between 1990 and 2004 by the same surgeon in our hospital. The patients were divided into seven groups according to age : 93 patients below 40 years of age [Group I], 419 patients aged $40{\sim}59$ [Group II], 115 patients aged $60{\sim}64$ [Group III], 82 patients aged $65{\sim}69$ [Group IV], 28 patients aged $70{\sim}74$ [Group V], 12 patients aged $75{\sim}79$ [Group VI] and 5 patients over the age of 80 [Group VII]. We then checked their medical history, Fisher's grade, Hunt-Hess grade, postoperative complications, and Glasgow Outcome Scale. Results : Age was not a statistically significant factor among patients below 70 years of age [P $value{\ge}0.05$]. But for those aged 70 and older, the age factor had a statistical value [P $value{\le}0.001$]. In addition, there was a close correlation between Hunt-Hess grade IV and V patients, and those with vasospasm, and hydrocephalus after surgery, with poor prognosis in elderly patients as well as young patients [P $value{\le}0.001$]. Conclusion : Advanced age [under the age of 70] dose not precluded adequate surgical treatment in patient with AN SAH, and we should be also alert to preventable causes of delayed neurological deterioration for improving the outcome in all elderly groups.

• Journal of Korean Neurosurgical Society
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• v.39 no.5
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• pp.360-365
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• 2006

Objective : This is a cadaver study to assess the accuracy of three cervical screw insertion techniques; the blind technique [Group I], the laminotomy technique [Group II], and the funnel technique [Group III]. Methods : Ten human cadavers embalmed with formaldehyde were prepared. After exposing the spinous processes, the laminas and the lateral masses, titanium alloy transpedicular screws were inserted from C3 to C7. A total of 100 pedicles were ramdomly assigned to one of three techniques [the blind technique : 31 screws, the laminotomy technique : 51 screws, the funnel technique: 18 screws]. Axial computed tomography with 1-mm slices, and sagittal and coronal reformation were performed to identify the accuracy of the screw insertion and the anatomic relationships. Results : In Group I, 9 screws [29%] were either contained within or penetrated less than 1mm, which were rated as successful. In Group II, 24 screws [47%] were successful. In Group III, 16 screws [89%] were successful. In the multiple comparison, there was a statistically significant difference between Groups I and III and between Groups II and III [$X^2$ test and Bonfenoni test]. Conclusion : The funnel technique can help a surgeon's understanding about the cervical pedicle more precisely than the other two techniques. The funnel technique is less dependent on lateral soft tissue retraction state.

• Journal of Korean Neurosurgical Society
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• v.29 no.1
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• pp.44-50
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• 2000

Objective : A few anecdotal cases of mesenchyme-derived tumors which grow into a cranial cavity have been reported that disclosed a dismal prognosis, due to their critical location, aggressive biological behavior, and high rate of surgical morbidity. The aim of this study is to search clinical factors related to these tumors. Methods : Eight patients who underwent surgical removal of intracranial mesenchymal tumors between January 1993 and December 1997 were studied retrospectively. The tumors included are three chordomas, two chondrosarcomas, two rhabdomyosarcomas, and one hemangiopericytoma. Authors compared clinical features, treatment, and results of our cases with reported cases. The mean follow-up period was 20.5 months. Results : All cases showed nonspecific, location-related clinical findings and arose from sphenopetroclival region. Single stage operation was performed in 4 cases, and skull base approaches in 3 cases. Adjuvant therapies were done in 2 cases. Recurrence was seen in 3 cases(37.5%), and 3 patients died. Interdisciplinary approach with otologic surgeon was done in 2 cases. Conclusion : Recent advancement of refined tactics has made these tumors amenable and provides prolongation of progression-free survival. These are modified skull base approaches, multi-modality treatment options, and inter-disciplinary team approaches. Good results may be expected for these mesenchymal tumors by aggressive resection and adjuvant therapies according to their biological nature.

• Journal of Korean Neurosurgical Society
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• v.58 no.6
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• pp.539-546
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• 2015

Objective : To report the learning curve of percutaneous endoscopic lumbar discectomy (PELD) for a surgeon who had not been previously exposed to this procedure based on the period and detailed technique with a retrospective matched comparative design. Methods : Of 213 patients with lumbar disc herniation encountered during the reference period, 35 patients who were followed up for 1 year after PELD were enrolled in this study. The patients were categorized by the period and technique of operation : group A, the first 15 cases, who underwent by the 'in-and-out' technique; group B, the next 20 cases, who underwent by the 'in-and-out-and-in' technique. The operation time, failure rate, blood loss, complication rate, re-herniation rate, the Visual Analogue Scale (VAS) for back and leg were checked. The alteration of dural sac cross-sectional area (DSCSA) between the preoperative and the postoperative MRI was checked. Results : Operative time was rapidly reduced in the early phase, and then tapered to a steady state for the 35 cases receiving the PELD. After surgery, VAS scores for the back and leg were decreased significantly in both groups. Complications occurred in 2 patients in group A and 2 patients in group B. Between the two groups, there were significant differences in operative time, improvement of leg VAS, and expansion of DSCSA. Conclusion : PELD learning curve seems to be acceptable with sufficient preparation. However, because of their high tendency to delayed operation time, operation failure, and re-herniation, caution should be exercised at the early phase of the procedure.

• Journal of Korean Neurosurgical Society
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• v.60 no.6
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• pp.684-690
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• 2017

Objective : As increasing the size of the geriatric population, the number of elderly patients, who need the surgery for painful degenerative spinal stenosis has been increasing. The geriatric population may be relatively high complications, because of age and age-associated medical conditions. However, there is a lack of studies addressing the perioperative complications and outcomes in elderly patients with posterior lumbar inter body fusion with screw augmentation (PLIF). Methods : We retrospectively reviewed the medical records and radiographic studies of geriatric patients who had spine surgery of PLIF due to spinal stenosis for 11 years. We divided into 2 groups (A; 70-75 years, B; over then 76 years) according to the age. Surgical level of each groups, hospital day and postoperative day, co-morbidities, complications, clinical outcomes were analyzed. Operative reports, hospital and outpatient clinic charts, and radiographic studies were reviewed. Results : Group A was composed of 80 patients, their mean age was 72.21 and female dominant (n=46), and their mean surgically fused level was 1.52 level. Group B was 36 patients, their mean age was 78.83 and female dominant (n=20), and their mean surgically fused level was 1.36 level. Comparing between two groups, complications, postoperative hospital stay were slightly increase in group B and co-morbidity was statistically high in group B, however clinical outcomes were similar between two groups. Conclusion : Increasing age might be an important risk factor for complications in patients undergoing PLIF, however, we would like to recommend that if the situation of spine of extreme geriatric patients need PLIF, it should be in the surgeon's consideration after careful selection and clinical judgement.

• Journal of Korean Neurosurgical Society
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• v.61 no.5
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• pp.568-573
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• 2018

Objective : Thoracic pedicles have special and specific properties. In particular, upper thoracic pedicles are positioned in craniocaudal plane. Therefore, manipulation of thoracic pedicle screws on the left side is difficult for right-handed surgeons. We recommend a new position to insert thoracic pedicle screw that will be much comfortable for spine surgeons. Methods : We retrospectively reviewed 33 patients who underwent upper thoracic pedicle screw instrumentation. In 15 patients, a total of 110 thoracic pedicle screws were inserted to the upper thoracic spine (T1-6) with classical position (anesthesiologist and monitor were placed near to patient's head. Surgeons were standing classically near to patient's body while patients were lying in prone position). In 18 patients, a total of 88 thoracic pedicle screws were inserted to the upper thoracic spine with the new standing position-surgeons stand by the head of the patient and the anesthesia monitor laterally and under patient's belt level. All the operations performed by the same senior spine surgeons with the help of C-arm. Postoperative computed tomography scans were obtained to assess the screw placement. The screw malposition and pedicle wall violations were divided and evaluated separately. Cortical penetration were measured and graded at either : 1-2 mm penetration, 2-4 mm penetration and >4 mm penetration. Results : Total 198 screws were inserted with two different standing positions. Of 198 screws 110 were in the classical positioning group and 88 were in the new positioning group. Incorrect screw placement was found in 33 screws (16.6%). The difference between total screw malposition by both standing positions were found to be statistically significant (p=0.011). The difference between total pedicle wall violations by both standing positions were found to be statistically significant (p=0.003). Conclusion : Right-handedness is a problem during the upper thoracic pedicle screw placement on the left side. Changing the surgeon's position standing near to patient's head could provide a much comfortable position to orient the craniocaudal plane of the thoracic pedicles.

• Journal of Chest Surgery
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• v.49 no.2
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• pp.80-84
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• 2016

Background: Video-assisted thoracoscopic surgery (VATS) pulmonary wedge resection has emerged as the standard treatment for primary spontaneous pneumothorax. Recently, single-port VATS has been introduced and is now widely performed. This study aimed to evaluate the outcomes of the Tower crane technique as novel technique using a 15-mm trocar and anchoring suture in primary spontaneous pneumothorax. Methods: Patients who underwent single-port VATS wedge resection in Chungnam National University Hospital from April 2012 to March 2014 were enrolled. The medical records of the enrolled patients were reviewed retrospectively. Results: A total of 1,251 patients were diagnosed with pneumothorax during this period, 270 of whom underwent VATS wedge resection. Fifty-two of those operations were single-port VATS wedge resections for primary spontaneous pneumothorax performed by a single surgeon. The median age of the patients was $19.3{\pm}11.5$ years old, and 43 of the patients were male. The median duration of chest tube drainage following the operation was $2.3{\pm}1.3days$, and mean post-operative hospital stay was $3.2{\pm}1.3days$. Prolonged air leakage for more than three days following the operation was observed in one patient. The mean duration of follow-up was $18.7{\pm}6.1months$, with a recurrence rate of 3.8%. Conclusion: The tower crane technique with a 15-mm trocar may be a promising treatment modality for patients presenting with primary spontaneous pneumothorax.

• International Journal of Control, Automation, and Systems
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• v.4 no.1
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• pp.30-41
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• 2006

The goal of this work is to develop and test a robot-assisted surgery system for spinal fusion. The system is composed of a robot, a surgical planning system, and a navigation system. It plays the role of assisting surgeons for inserting a pedicle screw in the spinal fusion procedure. Compared to conventional methods for spinal fusion, the proposed surgical procedure ensures minimum invasion and better accuracy by using robot and image information. The robot plays the role of positioning and guiding needles, drills, and other surgical instruments or conducts automatic boring and screwing. Pre-operative CT images intra-operative fluoroscopic images are integrated to provide the surgeon with information for surgical planning. Some experiments employing the developed robotic surgery system are conducted. The experimental results confirm that the system is not only able to guide the surgical tools by accurately pointing and orienting the specified location, but also successfully compensate the movement of the patient due to respiration.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.5
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• pp.480-488
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• 2008

Orthodontists often treat cases which are difficult to treat with conventional orthodontics. In such cases, it could be treated with surgical procedures with the help of an oral surgeon. Especially, transverse deficiency of the mandible can be corrected by widening the transverse width of mandibular symphysis, using distraction osteogenesis. Transverse widening of mandibular sympysis is known as a safe treatment but still complications could occur during the treatment. We are reporting some complications of cases that mandibular symphysis transverse widening were applied. Some cases showed complications because of the inappropriate osteotomy line. Since straight vertical osteotomy line was inclined to the left, only the left bony segment was likely to expand. According to bio-mechanical considerations, it will be better to perform a step osteotomy, cutting the eccentric area of the alveolar crest and the centric area of the basal symphyseal area. Complications could also occur by the failure of the distraction device. The tooth borne distraction device was attached on the lingual side of the tooth with composite resin. During the distraction period, it was impossible to obtain appropriate distraction speed and rhythm because of frequent fall off of the distraction device. Therefore, distraction device should be attached firmly with orthodontic band or bone screw, etc. Tooth mobility increasement could also occur as a complication. 'Walking teeth phenomenon' was observed during the distraction period, showing severe teeth mobility and pain during mastication. These symptoms fade out during the consolidation period. Since the patient could feel insecure and uncomfortable, it should be notified to the patient before the procedure. Finally, alveolar crestal bone loss could occur. Alveolar crestal bone loss occurred because of lack of distraction device firmness and teeth trauma caused by lower lip biting habit. Therefore, adequate firmness of the distraction device and habit control will be needed.