Surface Activated Titanium by Sodium Hydroxide Treatment for Bioactive Material Coating (rhBMP-2)

In order to activate dental implant surface for osseointegration, one of growth factor - recombinant human bone morphogenetic protein-2(rhBMP-2) coating on surface modified titanium with sodium hydroxide was designed. The physico- chemical properties of surface modified titanium and the rhBMP-2 eluting characteristic of the modified titanium were evaluated. The longer sodium hydroxide exposition time, the less eluting of rhBMP-2 on sodium hydroxide treated titanium was observed. Key words: Dental implant, surface modification, sodium hydroxide, hydrogen bonding, bone morphogenetic proteinope

Recent R & D Trends of Medical Adhesives and Anti-adhesion Membranes

In the case of surgical operation for the treatment of cancers, vascular diseases and diabetes mellitus, the use of medical (or biotissue) adhesives is gradually increasing instead of suturing. Together with this trend, the development of anti-adhesion membranes (or barriers) is rapidly increasing for preventing complications originated from post-operative tissue adhesions frequently occurring. In general, all medical devices should pass the testing for biological safety and effectiveness. Thus, newly developed medical adhesives and anti-adhesion membranes must be evaluated according to the well-regulated standard guidelines, such as ISO, OECD, ASTM, etc, under authorized institution, otherwise they cannot be commercialized. In this review, medical adhesives and anti-adhesion membranes were categorized and compared according to their use and materials followed by a brief description of the properties of products commercially available. Furthermore, this review dealt with the present state of commercialization, the size of market and the recent trends of research and development regarding medical adhesives and anti-adhesion membranes. Key words: Medical adhesives, Anti-adhesion membranes, Medical devices, Safety and Effectivenessope

Intradural Lumbar Disc Herniations Associated with Epidural Adhesion : Report of Two Cases

Intradural lumbar disc herniation (ILDH) is rare. In this report, authors present 2 cases of ILDHs associated with severe adhesion between the dural sac and posterior longitudinal ligament. In a 40-year-old man, ILDH occurred in association with epidural adhesion due to ossification of the posterior longitudinal ligament (OPLL). In other 31-year-old man, ILDH occurred in presence of epidural adhesion due to previous spine surgeryope

Direct-Current Treatment as a Safe Sterilization Method for Electrospun Biodegradable Polymer

Sterilization is an essential process for biodegradable polymers to be used as biomaterials or tissue engineered- scaffolds. The characteristics of biodegradable scaffolds can change due to decomposition of constituent polymers due to high temperature, pressure, or moisture during sterilization. This study investigated direct–current (DC) treatment as a safe method that can prevent structural change and deformation. Treatment of electrospun poly (lactic-co-glycolic acid) (PLGA) with DC showed a bactericidal effect within 40 sec at 4 V. When DC was applied at 6 V to the electrospun PLGA, the bactericidal effect emerged within 30 sec. The morphology of fibers and molecular weight of PLGA polymer was maintained after DC treatment. In contrast, electrospun PLGA exposed to ethylene oxide showed fiber degradation, and gamma or e-beam irradiation resulted in decreased molecular weight. The demonstrated improvement in chemical and physical stability of biodegradable polymers after DC sterilization may help extend their application.ope

Surgical treatment of primary spinal tumors in the conus medullaris

Objective: The objective of this study was to evaluate the characteristics and surgical outcome of the conus medullaris tumors. Methods: We retrospectively reviewed 26 patients who underwent surgery for conus medullaris tumor from August 1986 to July 2007. We analyzed clinical manifestation, preoperative MRI findings, extent of surgical resection, histopathologic type, adjuvant therapy, and outcomes. Results: There were ependymoma (13), hemangioblastoma (3), lipoma (3), astrocytoma (3), primitive neuroectodermal tumor (PNET) (2), mature teratoma (1), and capillary hemangioma (1) on histopathologic type. Leg pain was the most common symptom and was seen in 80.8% of patients. Pain or sensory change in the saddle area was seen in 50% of patients and 2 patients had severe pain in the perineum and genitalia. Gross total or complete tumor resection was obtained in 80.8% of patients. On surgical outcome, modified JOA score worsened in 26.9% of patients, improved in 34.6%, and remained stable in 38.5%. The mean VAS score was improved from 5.4 to 1.8 among 21 patients who had lower back pain and leg pain. Conclusion: The surgical outcome of conus medullaris tumor mainly depends on preoperative neurological condition and pathological type. The surgical treatment of conus medullaris tumor needs understanding the anatomical and functional characteristics of conus meudllaris tumor for better outcome.ope

Technical Strategies and Surgical Results of C1 Lateral Mass-C2 Pedicular Screw Fixation in Atlantoaxial Disorders

OBJECTIVE: There are various posterior fusion techniques in managing C1-2 instability. The aim of this study is to evaluate surgical techniques and clinical results including complications of the C1 lateral mass and C2 pedicle screw fixation (C1-2 LMPSF) in atlantoaxial disorders. METHODS: From February 1997 to July 2008, 24 patients were performed C1-2 LMPSF due to C1-2 instability. Pathway of vertebral artery was classified into three groups by 3D-angiogram. Diameter of C1 lateral mass and C2 isthmus on the plain X-ray and CT was measured before operation. Surgical method was divided into four groups according to fixation site (bilateral or unilateral) and bone graft (with or without graft). Stability of C1-2 fixation was postoperatively evaluated by flexion and extension cervical lateral films. We reviewed clinical data, imaging studies and old chart retrospectively as sources for analysis. RESULTS: Among 24 patients, os odontoideum was the most common cause (16 out of 24). Four patients had anomalous vertebral artery. Mean diameters of C1 lateral mass was 9.9(range 4.2~16.4) mm at right side, 10.3 (range 3.4~14.2) mm at left side. Mean diameter of C2 isthmus was 5.8 (range 1.0~10.1) mm at right side and 5.8(range 2.1~8.2) mm at left side. Two patients showed very narrow C2 isthmus. As a result, unilateral C1-2 LMPSF was performed on 6 patients (4 for anomalous vertebral arteries and 2 for narrow C2 isthmus). 12 of 18 patients were with C1-2 interlaminar bone graft and 6 patients without bone graft. All patients showed stable C1-2 fixation by flexion and extension cervical lateral X-ray films taken at least 6 months after surgery. Five out of 8 patients who had preoperative radiculopathy only showed improved symptoms. However, Seven out of 8 patients who had myelopathy showed little neurological improvement . CONCLUSION: For C1-2 LMPSF, preoperative 3D CT-angiogram study is mandatory to identify abnormal vertebral artery and narrow C2 isthmus. Bilateral C1-2 LMPSF without bone graft is enough to obtain stable C1-2 fixation. If there is an abnormal vertebral artery or narrow C2 isthmus, unilateral C1-2 LMPSF with bone graft and wiring is alternative successful methodope

Load Sharing Mechanism Across Graft-Bone Interface in Static Cervical Locking Plate Fixation

OBJECTIVE: This study is a retrospective clinical study over more than 4 years of follow up to understand the mechanism of load sharing across the graft-bone interface in the static locking plate (SLP) fixation compared with non-locking plate (NLP). METHODS: Orion locking plates and Top non-locking plates were used for SLP fixation in 29 patients and NLP fixation in 24 patients, respectively. Successful interbody fusion was estimated by dynamic X-ray films. The checking parameters were as follows : screw angle (SA) between upper and lower screw, anterior and posterior height of fusion segment between upper and lower endplate (AH & PH), and upper and lower distance from vertebral endplate to the end of plate (UD & LD). Each follow-up value of AH and PH were compared to initial values. Contributions of upper and lower collapse to whole segment collapse were estimated. RESULTS: Successful intervertebral bone fusion rate was 100% in the SLP group and 92% in the NLP group. The follow-up mean value of SA in SLP group was not significantly changed compared with initial value, but follow-up mean value of SA in NLP group decreased more than those in SLP group (p=0.0067). Statistical analysis did not show a significant difference in the change in AH and PH between SLP and NLP groups (p>0.05). Follow-up AH of NLP group showed more collapse than PH of same group (p=0.04). The upper portion of the vertebral body collapsed more than the lower portion in the SLP fixation (p=0.00058). CONCLUSION: The fused segments with SLP had successful bone fusion without change in initial screw angle, which was not observed in NLP fixation. It suggests that there was enough load sharing across bone-graft interface in SLP fixation.ope

Changes in anodized titanium surface morphology by virtue of different unipolar DC pulse waveform

Various unipolar DC pulse waveforms were selected to find the factors for controlling of the anodized titanium surface morphology. The current density, frequency and duty were ranged from 50 mA/cm2 to 750 mA/cm2, from 100 Hz to 400 Hz and from 10% to 50%, respectively. Increase of duty from 10% to 50% at 100 Hz in 0.1 M KOH provides larger pores — from 0.13 μm to 0.19 μm in average for 50 mA/cm2 and 0.15 μm to 0.24 μm for 750 mA/cm2. On the other hand increase of frequency from 100 Hz to 400 Hz at 50% duty provides smaller pores — from 0.19 μm to 0.17 μm for 50 mA/cm2 and 0.24 μm to 0.17 μm for 750 mA/cm2. Both duty and frequency are important factors to control the anodized titanium surface morphology.ope

Pre-wetting process with helium atmospheric pressure glow discharge for three-dimensional porous scaffold

Recently, three-dimensional polymer scaffolds were developed for tissue regeneration. Conventional pre-wetting processes require a lengthy processing time and have residue problems. In this study, a helium atmospheric pressure glow discharge (He-APGD) was employed as a pre-wetting process for porous poly-(L-lactide-co-ɛ-caprolactone) (PLCL) scaffold. The three minutes treated PLCL scaffold absorbed the culture media and contained grafted hydroxyl, carbonyl, and carboxyl groups. Moreover, it did not show cytotoxicity, did not require residual rinsing steps and showed a homogeneous cell distribution. The He-APGD treatment has a short processing time and promotes a homogenous cell distribution. Therefore, this pre-wetting process is expected to find many applications in the future.ope

Characterization of a silver-incorporated calcium phosphate film by RBS and its antimicrobial effects

A thin calcium phosphate film was synthesized on both commercially pure Ti and Si wafers by electron beam evaporation of hydroxyapatite as an evaporant with simultaneous Ar ion beam bombardments. Silver was introduced into an ion-beam-assisted deposition of a calcium phosphate thin film for antimicrobial effect. The amount of incorporated silver ions was controlled by immersing calcium-phosphate-coated samples in different AgNO3 concentrations, and Rutherford backscattering spectrometry (RBS) was employed to measure the amounts of substituted silver. The higher concentration of silver in the calcium phosphate film was more effective in reducing the bacteria of Escherichia coli ATCC 8739 and Streptococcus mutans OMZ 65 on contact with respect to controls.ope