• Journal of Korean Neurosurgical Society
• /
• v.40 no.6
• /
• pp.412-418
• /
• 2006

Objective : The safety of titanium metal cages in tuberculous spondylitis has not been investigated. We evaluated the outcome and complications of titanium mesh cages for reconstruction after thoracolumbar vertebrectomy in the tuberculous spondylitis. Methods : There were 17 patients with 18 operations on the tuberculous spondylitis in this study. Sixteen patients were operated with anterior corpectomy and reconstruction with titanium mesh cage followed by posterior transpedicular screw fixations on same day, two pateints were operated by either anterior or posterior approach only. After the affected vertebral body resection and pus drainage from the psoas muscle, titanium mesh cage, filled with morselized autogenous bone, was inserted. All the patients had antituberculosis medication for 18 months. The degree of kyphosis correction and the subsidence of cage were measured in the 15 patients available at a minimum of 2 years. Outcome was assessed with various cross-sectional outcome measures. Recurrent infection was identified by serial ESR[Erythrocyte Sedimentation Rate] and CRP[Cross Reactive Protein]. Results : There was no complication from the use of a titanium mesh cage. Recurrent infection was not detected in any case. Average preoperative of $9.2^{\circ}$ was reduced to $-2^{\circ}$ at immediate postoperative period, and on final follow up period kyphotic angle was measured to be $4.5^{\circ}$. Postoperatively, subsidence was detected in most patients especially at ambulation period, however further subsidence was prevented by the titanium mesh cage. Osseous union was identified in all cases at the final follow-up. Conclusion : The cylindrical mesh cage is a successful instrument in restoring and maintaining sagittal plane alignment without infection recurrence after vertebrectomy for tuberculous spondylitis.

• Journal of Korean Neurosurgical Society
• /
• v.41 no.3
• /
• pp.166-170
• /
• 2007

Objective : The purpose of this study is to evaluate the clinical outcome of the two-stage operation for thoracic tuberculous spondylitis. Methods : Eleven patients [4 male, 7 female] with thoracic tuberculous spondylitis were treated with two-stage operation. First stage consisted of anterior debridement and interbody fusion using rib graft and second with posterior instrumentation with fusion. Mean age was 46 years, and mean follow-up period was 18 months. All patients were treated with 12 months of antituberculotic medication postoperatively, and evaluated before and after surgery with respect to pain level, neurological status, associated lesions, hematological parameters and change of kyphotic angle. Results : The associated lesions were pulmonary tuberculosis in 4 cases. There were no recurrences of infection and bone union was obtained within 6 months of the operation in all cases. Changes in the pain severity, neurological status, and hematological parameters demonstrated significant clinical improvement in all patients. The mean kyphotic angle was corrected from $17.8^{\circ}$ to $9.8^{\circ}$ after surgery. The most recent follow-up of the mean kyphotic angle was $12.3^{\circ}$, with a loss of correction of $2.5^{\circ}$. The preoperative VAS averaged to be 7.18 [range, 4-10]. It decreased significantly an average of 1.45 [p <0001]. Conclusion : These results indicate that two-stage surgical treatment for thoracic tuberculous spondylitis provid safe and satisfactory results. Spine instability and kyphosis can be also prevented by two-stage operation.

• Journal of Korean Neurosurgical Society
• /
• v.40 no.2
• /
• pp.84-89
• /
• 2006

Objective : The purpose of this study is to compare the outcomes of two methods for stabilization and fusion : Postero-Lateral Fusion [PLF, pedicle screw fixation with bone graft] and Posterior Lumbar Interbody Fusion [PLIF, cage insertion] for spinal stenosis and recurred disc herniation except degenerative spondylolisthesis. Methods : Seventy one patients who underwent PLF [n=36] or PLIF [n=35] between 1997 and 2001 were evaluated prospectively. These two groups were compared for the change of interbody space, the range of segmental angle, the angle of lumbar motion, and clinical outcomes by Prolo scale. Results : The mean follow-up period was 32.6 months. The PLIF group showed statistically significant increase of the interbody space after surgery. However, the difference in the change of interbody space between two groups was insignificant [P value=0.05]. The range of segmental angle was better in the PLIF group, but the difference in the change of segmental angle was not statistically significant [P value=0.0l7]. Angle of lumbar motion was similar in the two groups. Changes of Prolo economic scale were not statistically significant [P value=0.193]. The PLIF group showed statistically significant improvement in Prolo functional scale [P value=0.003]. In Prolo economic and functional scale, there were statistically significant relationships between follow-up duration [P value<0.001]. change of interbody space [P value<0.001], and range of segmental angle [P value<0.001]. Conclusion : Results of this study indicate that PLIF is superior to PLF in interbody space augmentation and clinical outcomes by Prolo functional scale. Analysis of clinical outcomes showed significant relationships among various factors [fusion type, follow-up duration, change of interbody space, and range of segmental angle]. Therefore, the authors recommend instrumented PLIF to offer better clinical outcomes in patients who needed instrumented lumbar fusion for spinal stenosis and recurred disc herniation.

• Journal of Korean Neurosurgical Society
• /
• v.60 no.2
• /
• pp.174-180
• /
• 2017

Objective : Proximal junctional kyphosis (PJK) is radiologic finding, and is defined as kyphosis of >$10^{\circ}$ at the proximal end of a construct. The aim of this study is to identify factors associated with PJK after segmental spinal instrumented fusion in adults with spinal deformity with a minimum follow-up of 2 years. Methods : A total of 49 cases of adult spinal deformity treated by segmental spinal instrumented fusion at two university hospitals from 2004 to 2011 were enrolled in this study. All enrolled cases included at least 4 or more levels from L5 or the sacral level. The patients were divided into two groups based on the presence of PJK during follow-up, and these two groups were compared to identify factors related to PJK. Results : PJK was observed in 16 of the 49 cases. Age, sex and mean follow-up duration were not statistically different between two groups. However, mean bone marrow density (BMD) and mean back muscle volume at the T10 to L2 level was significantly lower in the PJK group. Preoperatively, the distance between the C7 plumb line and uppermost instrumented vertebra (UIV) were no different in the two groups, but at final follow-up a significant intergroup difference was observed. Interestingly, spinal instrumentation factors, such as, receipt of a revision operation, the use of a cross-link, and screw fracture were no different in the two groups at final follow-up. Conclusion : Preoperative BMD, sagittal imbalance at UIV, and thoracolumbar muscle volume were found to be strongly associated with the presence of PJK.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.35 no.2
• /
• pp.106-111
• /
• 2009

Bisphosphonates have been approved for Paget's disease, cancer-related hypercalcemia, bone involvement in multiple myeloma or solid tumors and osteoporosis. Although, underlying pathophysiological mechanisms remain unclear, it seems that bisphosphonates inhibit osteoclast precursor cells, modulate migratory and adhesive characteristics and induce apoptosis of osteoclasts. Furthermore impacts on angiogenesis, microenvironment and signal transduction between osteoclasts and osteoblasts. In this report, we present a case of oral bisphosphonates induced osteonecrosis of the mandible in a 84-year-old patient who received for two years. Two tapered screw vent implants(Zimmer, USA) were placed in the area of first and second molar. Two weeks later after crowns restored, some inflammatory signs and symptoms were observed on the second molar area. Sequestrum was formed and the sequestrum was removed with the implant. Frequent follow-up checks and oral hygiene maintenances were done and the first molar implant was restored. There is insufficient evidence suggests that duration of oral bisphosphonate therapy correlates with the development and severity of osteonecrosis. Therefore, dentists should not overlook the possibility of development of bisphosphonate induced osteonecrosis in patients who have taken oral forms of medication for less than three years.

• The Journal of Korean Academy of Prosthodontics
• /
• v.33 no.4
• /
• pp.807-823
• /
• 1995

The purpose of this study was to analyze the stress distribution and the displacement happened to the abutment, the prosthesis, and the surrounding structure according to the location of the nonrigid connector, that is, the keyway in the distal of canine and the mesial of the implant in the three unit fixed partial denture. Two-dimensional finite element model ws constructed and analyzed for the stress distribution and the displacement using software ABAQUS(Ver 5.2 Hibbitt, Karisson & Sorenson, Inc., 1992). After finishing the finite element model, the distribution load of 15kg was applied simultaneously to the all cusp tips of the prosthesis and the concentration load of 10㎏ was applied respectively at the each cusp tip of the prosthesis. The following results were obtained : 1. The amount of displacement of the implant was greater in case of the non-rigid connection than the rigid connection, and the more favorable displacement was shown in case of the IKb than the IKa. 2. Without regard to the connection method, the stress represented at the surrounding bone was similar, and the more favorabel stress distribution was shown in case of IKb. 3. The maximum stress was concentrated at the fastening screw and the neck of implant in all experimental groups, and their stress magnitudes were in the order of IKb, IR, and IKa.

• The Journal of Advanced Prosthodontics
• /
• v.11 no.6
• /
• pp.341-349
• /
• 2019

PURPOSE. A novel retentive type of implant prosthesis that does not require the use of cement or screw holes has been introduced; however, there are few reports examining the biomechanical aspects of this novel implant. This study aimed to evaluate the biomechanical features of cementless fixation (CLF) implant prostheses. MATERIALS AND METHODS. The test groups of three variations of CLF implant prostheses and a control group of conventional cement-retained (CR) prosthesis were designed three-dimensionally for finite element analysis. The test groups were divided according to the abutment shape and the relining strategy on the inner surface of the implant crown as follows; resin-air hole-full (RAF), resin-air hole (RA), and resin-no air hole (RNA). The von Mises stress and principal stress were used to evaluate the stress values and distributions of the implant components. Contact open values were calculated to analyze the gap formation of the contact surfaces at the abutment-resin and abutment-implant interfaces. The micro-strain values were evaluated for the surrounding bone. RESULTS. Values reflecting the maximum stress on the abutment were as follows (in MPa): RAF, 25.6; RA, 23.4; RNA, 20.0; and CR, 15.8. The value of gap formation was measured from 0.88 to 1.19 ㎛ at the abutment-resin interface and 24.4 to 24.7 ㎛ at the abutment-implant interface. The strain distribution was similar in all cases. CONCLUSION. CLF had no disadvantages in terms of the biomechanical features compared with conventional CR implant prosthesis and could be successfully applied for implant prosthesis.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.21 no.2
• /
• pp.131-138
• /
• 1999

The purpose of this study is to evaluate the effects of resorbable plate in the healing process of mandibular fracture. Reduction and rigid fixation was carried out on the artificial mandibular fracture site of the rabbits, using a resorbable screw, 1.5mm in diameter and 4.0mm in length, and an absorbable plate 1.5mm in thickness(Lactosorb$^{(R)}$). En block tissue specimens with plate were taken from the rabbits at 4, 6, 8, and 10 weeks intervals and specimen were observed with light microscope under the hematoxylin-eosin staining, to observe the inflammatory reaction and tissue healing process. The following conclusions were drawn: 1. The subject displayed good healing with no signs of detachment of the fixation plate. 2. At 4 weeks, the plate was covered by the connective tissue. Then at 6 weeks, bone regeneration was discovered around the plate. 3. During the period of healing, no inflammatory reaction or foreign body reaction, as a result of using resorbable plate, were observed. 4. At 8 weeks, the initial phase of the absorption of the plate was observed. Then at 10 weeks, macrophage were observed around the plate, indicating the absorption phase was in process. From the above results, it can be determined that when the resorbable plate is applied to rabbit, full recuperation occurs naturally in the absence of inflammatory reaction and foreign body reaction. The selected study is clinically valuable in proving this procedure.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.21 no.1
• /
• pp.60-64
• /
• 1999

Recently, for the reconstruction of bony defect and cosmetic improvement, many graft materials and implants have been widely used in the various surgical situations. The alloplastic materials have many advantages such as simplicity of operation, no additional need of surgery, and easy manipulation. The $Medpor^{TM}$(porous high-density polyethylene, Porex Co., USA) was initially studied in 1972 for surgical implant and introduced as an implant material for oral and maxillofacial region by Sauer and King in 1988. This material permits full ingrowth of bone into the implants, substantially increasing the implant's incorporation into the recipient site. It can be shaved during the surgery, which results in an improvement and prefabricated various size and shapes to fit into the surgical defect. The $Medpor^{TM}$ was used in 32 patients from 1995 to 1997 at the maxillofacial region. It was used for paranasal augmentation in 24 cases, for malar augmentation in 2 cases, for infraorbital augmentation in 2 cases, for mandibular angle augmentation in 2 cases, for mandibular body augmentation in 2 cases, for chin vertical augmentation in 1 case. It was mainly fixed with miniplate or screw. There were few complications except one infection and one exposure of the implant.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.31 no.2
• /
• pp.127-135
• /
• 2009

Objectives : The titanium fixation system has been used in orthognathic surgery for fixation of bone segments usually, but the biodegradable fixation system was developed and also being used. The strongest point in the biodegradable system is that no extra operation should be needed to remove fixation materials. In spite of this merit, oral & maxillofacial surgeons hesitate to use this system in fracture or orthognathic surgery. In this study, as we got some clinical experiences, we'd like to report the result of clinical study using the biodegradable fixation system in orthognathic surgery. Patients and Methods : A total of 35 patients composed of 17 males and 18 females with 25 osteotomies in maxilla and 34 osteotomies in mandible were fixated with the biodegradable fixation system(Inion $CPS^{(R)}$). We investigated methods of stabilization, fixation time, and complications on the basis of the method as above. Results : Four 2mm thick L shaped plates with 7 holes of which 1 hole was removed were fixed in maxilla with six $2.0{\times}7mm$ screws. Three $2.5{\times}16{\sim}18mm$ screws were used to fix superior ramus area and one mandibular angle area in mandible. It took about 27.4 minutes in maxilla, 25.3 minutes in mandible to perform the fixation which took longer time than the titanium system(9.5 minutes in maxilla, 8 minutes in mandible). Generally, there was no problem except 9 cases in which there were some complications. Conclusions : In most cases, the biodegradable fixation system can be used without problem in usual orthognathic surgery. But, this system is inferior to the titanium fixation one in some respects such as fixation time, size, and physical property. Some supplementations for such weak points as aforementioned should be needed for the universal use of biodegradable materials.