• The Journal of Korean Academy of Prosthodontics
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• v.18 no.1
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• pp.15-35
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• 1980

The purpose of this study was to investigate stresses in the various components of fixed partial dentures restoring the posterior teeth of the lower jaw, and to measure quantitatively the effects of certain modifications in structural design on the stresses in the restorations using two-dimensional photoelasticity. Two-dimensional photoelastic methods were used in this study. Several models of fixed partial dentures were constructed. Shoulder less margins and anatomic occlusal reduction were incorporated in Model 1. Rounded shoulders and flat occlusal reduction were incorporated in Model 2, while Model 3 was a cantilever fixed partial denture. Other similar fixed partial dentures were constructed with V and U notches deliverately included in the region of the fixed joints for comparative reasons. The birefringent materials used in this study were PSM-1 and PSM-5 in standard sheets. PSM-1 was used for constructing the substructure, and PSM-5 was used in making the components of the fixed partial dentures. The two materials were used in the construction of composite photoelastic models. Improved artificial stone was used to represent dental cement in luting the composite photoelastic models. Static loading procedures were used at preplanned sites to represent occlusal loads in the mouth. 35 mm color and B/W film were used to record isochromatics in accordance with photoelastic procedures. Data reduction was performed using the grid method, which helped in, the mathematical integration procedure (Shear difference method) to separate the principal stresses. The results were as follows. 1. Fixed partial dentures do not function in bending as a symmetrical beam. Alternate areas of tension and compression were demonstrated when multiple contact loading was used. 2. The weakest part in posterior fixed partial dentures is the fixed joint. 3. (1) Models I and modified Model I were loaded on the pontic using a 50 pound vertical static load. The shear stress near the posterior fixed joint in Model 1 (U notches) was+129.4 p.s.i., and at the same fixed joint in modified Model 1 (V notches) was+239.4 p.s.i. The concentration of stress in fixed joint was reduced by 50% when U notches replaced the V notches. (2) Modified Model 2 was loaded using a multiple contact loader at a total load of 125 pounds. The difference between the principal stresses (${\sigma}_1-{\sigma}_2$), shear stress, at the V notches was+600 p.s.i., and at the U notches was+3l7 p.s.i. The shear stress was reduced by 50% when U notches replaced the V notches. V-grooves at the fixed joints should be avoided, and should be replaced by regular shaped U-grooves. 4. Cantilever fixed partial dentures had much higher stresses at the fixed joint than fixed partial dentures that were attached at both ends.

• Tuberculosis and Respiratory Diseases
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• v.45 no.1
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• pp.169-175
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• 1998

Background: Heliox is known to decrease $PaCO_2$ in patients with increased airway resistance by increasing minute ventilation and reducing work of breathing(WOB). Besides these effect, heliox is expected to decrease functional anatomic dead space owing to improvement of peak expiratory flow rate(PEFR) and enhancement of gas distribution. We investigated whether heliox can decrease $PaCO_2$ even at the same minute ventilation (VE) and WOB with $N_2-O_2$ to speculate the effect of the heliox on the anatomic dead space. Material and Method: The subjects were 8 mechanically ventilated patients with asthma or upper airway obstruction(M : F=5 : 3, $68{\pm}10$years) who were under neuromuscular paralysis. The study was consisted of three 15-minutes phases: basal $N_2-O_2$ heliox and washout Heliox was administered via the low pressure inlet of servo 900C, and respiratory parameters were measured by pulmonary monitor(CP-100 pulmonary monitor, Bicore, Irvine, CA, USA). To obtain the same tidal volume(Vt) in heliox phase, the Vt on monitor was adjusted by the factor of relative flow rate of heliox to $N_2-O_2$. Dead space was calculated by Bohr equation. Results: 1) Vt, VE, peak inspiratory pressure(PIP) and peak inspiratory flow rate(PIFR) were not different between $N_2-O_2$ and heliox. 2) PEFR was higher on heliox($0.52{\pm}0.19$L/sec) than $N_2-O_2$($0.44{\pm}0.13$L/sec)(p=0.024). 3) $PaCO_2$(mmHg) were decreased with heliox($56.1{\pm}14.1$) compared to $N_2-O_2$($60.5{\pm}15.9$)(p=0.027). 4) Dead space ventilation(%) were decreased with heliox($73{\pm}9$ with $N_2-O_2$ and $71{\pm}10$ with heliox)(p=0.026). Conclusion: Heliox decreased $PaCO_2$ even at the same VE and WOB with $N_2-O_2$, and the effect was considered to be related with the reduction of anatomic dead space.

• Archives of Hand and Microsurgery
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• v.23 no.4
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• pp.230-238
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• 2018

Purpose: Metacarpal fractures are common injuries of the hand. They are treated using closed reduction (CR) or open reduction (OR) techniques. The management strategy depends on fracture site characteristic and fixation methods. In this study, we evaluated pre- and postoperative fracture angulation, when metacarpal fractures bad been treated using two different techniques: CR with parallel transverse pinning and OR with plate fixation. Methods: Forty-six patients undergoing anatomic reduction to treat extra-articular metacarpal fractures were recruited. They were included in one of two therapeutic groups: Group 1, CR with parallel transverse pinning (n=21); Group 2, OR with plate fixation (n=25). Fracture angulation values have been measured on pre- and postoperative radiologic images. Values were compared between pre- and postoperative states, and between corresponding measurements of each group. Results: All extra-articular metacarpal fractures were successfully treated without wound related complications or the limit of joint motion. Both groups demonstrated adequate reduction at immediate postoperative period (postoperative angulation of group 1, $20^{\circ}{\pm}7^{\circ}$; group 2, $19^{\circ}{\pm}5^{\circ}$). During the observation at follow-up period, Group 1 exhibited slight recurrence (follow-up angulation of group 1, $24^{\circ}{\pm}10^{\circ}$). Nonetheless, Group 2 showed adequate reduction state in both immediate postoperative and long-term follow-up periods (follow-up angulation of group 2, $18^{\circ}{\pm}6^{\circ}$). Conclusion: Extra-articular metacarpal fractures were successfully restored without functional complications. CR with parallel transverse pinning method exhibited recurrence after pin removal, which necessitates cautious postoperative exercise and monitoring.

• Archives of Reconstructive Microsurgery
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• v.16 no.1
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• pp.48-51
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• 2007

There could be several methods for trochanteric reconstruction including local flap, pedicled perforator flaps, free flap, etc. We performed greater trochanteric reconstruction with lumbar artery perforator free flap in some aberrant method. So we report this experience with review of literatures. A 42-year-old man visited our hospital with a large soft tissue defect in his left greater trochanteric area by traffic accident. The patient had wide skin and soft tissue defect combined with open femur fracture. During one month period of admission, he underwent femur open reduction and wound debridement four times. After that we planned thoracodorsal perforator free flap reconstruction. The flap was outlined as large as $20{\times}15\;cm$ and elevated in a suprafascial plane from the lateral border. During intramuscular perforator dissection, we found that two 1.5 mm diametered perforator vessels coursed inferomedially toward second lumbar region. Finally the flap became lumbar artery perforator flap based on second lumbar artery perforator as a main pedicle. After flap transfer, the perforator vessels were connected with inferior gluteal artery and vein microsurgically. The operation was successful without uneventful course. We found no significant postoperative complication and donor site morbidity during six months follow up periods. Lumbar artery perforator flap could be an alternative procedure for thoracodorsal perforator flap in some patients with anatomic variant features.

• The Korean Journal of Pain
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• v.12 no.2
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• pp.238-241
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• 1999

Intractable pain arising from disorders of the viscera and somatic structures within the pelvis and perineum often poses difficult problems for the pain pratitioner. The reason for this difficulty is that the region contains diverse anatomic structures with mixed somatic, visceral, and autonomic innervation affecting bladder and bowel control and sexual function. Clinically, sympathetic pain in the perineum has a distinctly vague, burning, and poorly localized quality and is frequently associated with the sensation of urgency. Although various approaches have been proposed for the management of intractable perineal pain, their efficacy and applications are limited. Historically, neurolytic blockade in this region has been focused mainly on somatic rather than sympathetic components. The efficacy of neurolytic ganglion impar block has been demonstrated in treating perineal pain without significant somatovisceral dysfunctions for patient with advanced cancer in 1990. The introduction of superior hypogastric plexus block in 1990 demonstrated its effectiveness in patients with cancer related pelvic pain. In our report, five patients had advanced cancer (rectal caner 3; cervix cancer 1; metastases to sacral portion of renal cell cancer 1). Localized perineal pain was present in all cases and was characterized as burning and urgent with 9~10/10 pain intensity. After neurolytic block of ganglion impar, patients experiened incomplete pain reduction (7~8/10), as determined by the VAS (visual analogue scale), and change in pain site. We then treated with superior hypogastric plexus block, which produced satisfactory pain relief (to less than 4/10), without complication.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.6
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• pp.559-564
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• 2006

According to the development of operation technique and biologic materials, oromaxillofacial surgery department have used many kinds of metal and biologic materials in ORIF and plastic surgery. In maxillofacial fracture, ORIF with metal plate and screw have short healing period and good prognosis. But ORIF with metal materials have many complications as maxillofacial abnormal growth, screw loosening, bone malunion. And metal materials have not used in infection site. The purpose of this study is to evaluate the clinical value of 10 condylar fracture patients operated with absorbable screw at Wonkwang university. Ten patients(8 males, 2 female, mean aged 28) who had mandibular condyle process fracture treated with PLLA implants(poly-l-lactide) was recalled for follow-up clinical and radiologic examination for 10 years. Mouth opening recorvered to more than 35mm and occlusion was stable in all patients. All fractured mandibular condyles showed anatomic good reduction and long-term stability with the use of resorbable miniplates and screw. Bone healing was satisfactory in all patients, and there was no evidence of abnormal resorption of condylar process.

• Journal of Korean Foot and Ankle Society
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• v.21 no.1
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• pp.21-26
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• 2017

Purpose: To evaluate the clinical outcome of an operation with early rehabilitation from ankle fracture in accordance with the injury type. Materials and Methods: A total of 136 patients (70 males and 66 females) who underwent surgery and early rehabilitation for ankle fractures between December 2008 and December 2013 were retrospectively reviewed. The average age was 47.9 years, with a range of 18~79 years. The mean follow-up period was 28.7 months, with a range of 24~102 months. All patients were classified in accordance with the Lauge Hansen classification and anatomic fracture site. Moreover, the presence of ligament injuries were documented. A short-leg cast was applied postoperatively for two weeks; thereafter, patients began the range-of-motion exercises after cast removal. Full weightbearing was allowed at 2 weeks postoperatively. Each patient was assessed radiologically and clinically based on the OlerudMolander score, visual analogue scale (VAS) for pain, joint stiffness, and capability of single heel raising. Results: Seventeen patients (12.5%) complained of postoperative pain (VAS score 1~3), and the incidence was higher in patients with trimalleolar fractures or associated ligament injuries. Twenty-three patients (16.9%) complained of postoperative ankle stiffness. The mean Olerud-Molander score was 75.4/80 (range, 55~80). Olerud-Molander scores were lower in patients with ligament injuries than in those with fracture alone. There was no nonunion or fracture displacement even after early weightbearing walking. Conclusion: In this retrospective series, early rehabilitation after surgical restoration of ankle mortise by anatomical reduction and stabilization was shown to be successful. Earlier motion exercise and weightbearing walking can minimize fracture complications like joint stiffness or weakness in ankle fracture.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.2
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• pp.143-153
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• 2006

Temporomandibular joint(TMJ) ankylosis is characterized by the formation of bony or fibrous mass, which replaces the normal articulation. Ankylotic block formation causes reduction of mandibular mobility, particularly hindering mouth opening, due to a mechanical block of the condylar head in its roto-transfatory motion. Surgery in TMJ ankylosis treatment entails complete ankylotic block removal and subsequent arthroplasty, possibly with autologous tissue between articular surfaces or heterologous material to restore the anatomic structure and normal function. Temporalis myofascial flap holds great promise for the reconstruction of various maxillofacial defects. In more recent years, a pedicled temporalis myofascial flap has been advocated in TMJ ankylosis surgery. Advantages of the temporalis myofascial flap in TMJ reconstruction include close proximity to the TMJ, adequate blood supply from the internal maxillary artery, and its attachment to the coronoid process, which provides movement of the flap during function, simulating physiologic action of the disc. This study evaluated 8 patients(11 TMJs) affected by TMJ ankylosis. All patients underwent surgical treatment of the removal of the ankylotic block and subsequent interpositional arthroplasty with temporalis myofascial flap. Bilateral TMJ ankylosis was observed in 3 patients(6 TMJs), right-sides in 3 patients, left-sided in 2 patients. Epipathogenesis was traumatic in 6 patients(8 TMJs), ankylosing spondylitis in 2 patients(3 TMJs). In 3 patients coronoidotomy was underwent. Average follow-up was 16.8 months after surgery, with a range of 7 to 28 months. No patients underwent additional TMJ procedures after the temporalis myofascial flap. All patients showed a distinctive improvement both in articular functionality and symptoms. We found that temporalis myofascial flap is very valuable in reconstruction of TMJ ankylosis.

• Archives of Craniofacial Surgery
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• v.10 no.1
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• pp.55-60
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• 2009

Purpose: For blowout fracture of the medial orbital wall, the goals of treatment are complete reduction of the herniated soft tissue and anatomic reconstruction of the wall without surgical complications. Surgeons frequently worry about damage to the optic nerve from the dissection, when the part over the posterior ethmoidal foramen was fractured. The authors performed small incision and inlay grafting for reconstruction of medial orbital wall fracture. Methods: Between January 2007 and April 2008, 15 out of 32 patients were included in an analysing the outcome of corrected medial orbital wall fracture. In 15 patients of posterior comminuted fracture of medial orbital wall, insertion of porous polyethylene($Medpor^{(R)}$ channel implant, Porex, USA) to ethmoidal sinus was performed in multiple layer, through the transconjunctival approach (inlay grafting). Results: In all cases, the orbital bone volume was reconstructed in its normal anatomical position. The associated ocular problems disappeared except for mild enophthalmos in 2 patients and there were no surgical complications associated with inlay grafting. Conclusion: The advantage of inlay grafting include anatomical reconstruction of the orbital wall; the avoidance of optic nerve injury; the simplicity of the procedure; and consequently, the absence of surgery-related complications. This technique is presented as one of the preferred treatments for posterior comminuted fracture of medial orbital wall.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.42 no.5
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• pp.259-264
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• 2016

Objectives: We evaluated and recorded post-traumatic and postoperative neurosensory deficits of the inferior alveolar nerve (IAN) in mandibular fracture in order to identify associated risk factors. Materials and Methods: This was a prospective cohort study composed of 60 patients treated for mandibular fracture. The primary study variable was the change between the post-traumatic IAN neurosensory examination score and the score after fracture reduction. Risk factors were categorized as demographic, anatomic, fracture displacement, and treatment. Appropriate descriptive and bivariate statistics were computed. Results: Sixty patients with unilateral mandibular fracture reported within 24 hours of injury were evaluated over a one-year period. A post-traumatic neurosensory deficit was observed in 52 patients (86.7%), the percentage of which was reduced to 23.3% over the follow-up period. Abnormal postoperative neurosensory scores were significantly higher in angle fracture cases (33.3%) compared to body fracture cases (11.1%). When recovered and non-recovered neurosensory scores were compared by fracture location, 88.9% of body fracture cases showed significant recovery compared to 66.7% of mandibular angle fracture cases. Cases with less than 5 mm fracture displacement showed statistically significantly higher neurosensory recovery scores (90.6%) compared to those with more than 5 mm fracture displacement (60.7%). Conclusion: Use of a miniplate with mono-cortical screws does not play a role in increasing IAN post-traumatic neurosensory deficit. Early management can reduce the chances of permanent neurosensory deficit. Mandibular fracture displacement of 5 mm or more and fracture location were found to be associated with an increased risk of post-traumatic IAN neurosensory score worsening.