Auricular cartilage versus donor sclera as a wrapping of hydroxyapatite orbital implants

AIM: To retrospectively compare postoperative outcomes after primary enucleation and placement of a hydroxyapatite(HA) implant without wrapping, wrapped with auricular cartilage or donor sclera. METHODS: Medical records of patients presented as intraocular tumor or severe ocular injury were identified from the electronic medical record system. Cases underwent enucleation and HA orbital implantation were enrolled in this study and were divided into 3 groups according to the wrapping material of HA implant. Cases with autogenous cartilage caps were enrolled in group A(n=11), with donor sclera caps in group B(n=12), and without any wrapping material in group C(n=9). Follow-ups were set at 1, 2 wk, 1, 3, 6, and 12 mo after surgery.RESULTS: Altogether 32 cases finished the followup and were enrolled in this study. Three cases(27.27%) in group A, 4 cases(33.33%) in group B, and 4 cases(44.44%) in group C developed one complication each after surgery. In group A, no HA exposure occurred, but conjunctival inclusion cyst occurred in one and severe conjunctive chemosis in two cases. In group B, one HA exposure occurred, conjunctive inclusion cysts occurred in one, severe conjunctive chemosis occurred in one, and conjunctival granuloma occurred in one case. In group C, one HA exposure occurred, severe conjunctive chemosis occurred in two cases, and conjunctival granuloma occurred in one case. The case of exposure of none-wrapped implant was noted in the first 6 mo after placement of the orbital implant. The case of exposure of donor sclerawrapped implant was noted at the 12 mo after placement of the orbital implant. Both exposure cases were treated successfully with conservative treatment.CONCLUSION: With low incidence of implant exposure and mild complications, auricular cartilage can be a good choice of alternative wrapping material of orbit implant with satisfied outcome.

Effects of Vascular Endothelial Cell Growth Factor on Fibrovascular Ingrowth into Rabbit's Hydroxyapatite Orbital Implant

Summary: The effects of different concentrations of vascular endothelial cell growth factor (VEGF) on the fibrovascular ingrowth into rabbits hydroxyapatite orbital implant were investigated. Twelve New Zealand white rabbits were divided into 3 groups and received hydroxyapatite orbital implant surgery in their right eyes. Before and after the operation, the implants were treated with 10 ng/ml VEGF, 100 ng/ml VEGF, or normal saline as control group. The animals received technetium bones scan at 2, 4, and 6 weeks postoperatively. The mean radioactivity counts within region of interest (ROI) of the surgery eye (R) and the non-surgery eye (L) in the same animal were tested, and the R/L ratios were calculated. The implants were harvested at 6th weeks and examined histopathologically. The results showed that at second week, there was no significant difference in mean R/L ratios between VEGF group and control group (F=2.83, P=0.111); At 4th week (F=7.728, P=0.011) and 6th week (F=7.831, P=0.011) postoperatively, the mean ratios in VEGF groups were significantly higher than that in control group. At 6th week postoperatively, the fibrovascularization rates in VEGF groups were higher than in control group significantly (F=8.711, P=0.008). It was suggested that VEGF could promote the fibrovascular ingrowth into hydroxyapatite orbital implant, thus might shorten the time required for complete vascularization of the HA orbital implant.

Comparative study of modified and conventional secondary hydroxyapatite orbital implantations

AIMTo compare the clinical effects of the modified and conventional secondary hydroxyapatite orbital implantations.

Effect research of the hydroxyapatite orbital implant on orbital development in children

Objective To evaluate the clinical effect of a surgical procedure to reconstruct socket with hydroxyapatite in the anophthalmic children. Method Hydroxyapatite was wrapped up with scleral or dura mater shell as a orbital implant. 53 consecutive patients were involved, 34 of whom had been referred for primary implantation surgery, and 19 for secondary implantation surgery. 3 patients had been drilled. Result There were no cases of orbital infection, implant extrusion, implant exposure or migration in 1～76 months of follow up. All children achieved a better facial appearance. The children who undergone drilling and peg placement had excellent prosthesis motility, on the contrary the effect was not very good. Conclusion The hydroxyapatite orbital implant give good cosmetic results with a low rate of complications, promotes orbital development, and helps to children’s normal body and mind growth.

Autologous sclera-muscle flaps technique in evisceration with hydroxyapatite implantation

·AIM: To provide superior cosmetic results and reduce complications, unlike traditional evisceration coupled with implant insertion technique and its modifications,we have developed a novel and simple technique for anophthalmic patients.·METHODS: All patients who underwent the scleral-muscle flaps procedure in evisceration with the placement of hydroxyapatite implant were included in the study. Main outcome measures were complications such as exposure, infection, chemosis, conjunctival inclusion cysts, granulomas. Meanwhile, implant motility was indirectly measured and the results were collected and analyzed.· RESULTS: A total of twenty-eight patients were enrolled in the study. Eighteen were men(64.29%) and ten were women(35.71%). Ages ranged from 18 to 65y(mean age, 32 years old). Mean follow-up was 12.32mo(range, 9-16mo). All patients received a hydroxyapatite implant. The average diameter of the implant was 19.29 ±1.36 mm(range, 18-22 mm). Minor complications occurred in 3 patients, and a major complication was observed in 1 patient. Mean motility were 11.04 ±1.45 mm horizontally(range, 7-14 mm) and 8.57 ±1.50 mm vertically(range, 5-12 mm).·CONCLUSION: The sclera-muscle flaps technique in evisceration with hydroxyapatite implantation is simple and practical that eases the surgical procedure, enables a proper size hydroxyapatite implantation, distinctively reduces complications and provides superior surgery results, especially the motility of the implant.

Calcium phosphate conversion technique:A versatile route to develop corrosion resistant hydroxyapatite coating over Mg/Mg alloys based implants

Globally,vast research interest is emerging towards the development of biodegradable orthopedic implants as it overcomes the toxicity exerted by non-degradable implants when fixed in the human body for a longer period.In this context,magnesium(Mg)plays a major role in the production of biodegradable implants owing to their characteristic degradation nature under the influence of body fluids.Also,Mg is one of the essential nutrients required to perform various metabolic activities by the human cells,and therefore,the degraded Mg products will be readily absorbed by the nearby tissues.Nevertheless,the higher corrosion rate in the biological environment is the primary downside of using Mg implants that liberate H2gas resulting in the formation of cavities.Further,in certain cases,Mg undergoes complete degradation before the healing of damaged bone tissue and cannot serve the purpose of providing mechanical support.So,many studies have been focused on the development of different strategies to improve the corrosion-resistant behavior of Mg according to the requirement.In this regard,the present review focused on the limitations of using pure Mg and Mg alloys for the fabrication of medical implants and how the calcium phosphate conversion coating alters the corrosive tendency through the formation of hydroxyapatite protective films for enhanced performance in medical implant applications.

A Research on Hydroxyapatite Front Tooth Implantation

Hydroxyapatite (HA) bio-ceramics implant tooth was tested through animal experiment and clinical application. HA tooth was placed into the fresh extraction socket. At first, HA tooth was chosen and implanted as fixed maxillary front tooth in domestic rabbit immediately after extraction of tooth. Three to six months later satisfactory osseointegration between implanted HA teeth and periodontinum was observed. Clinically, 28 teeth in 25 patients were implanted with suitable HA teeth, chosen according to dental X-ray and models of different kinds of HA dental root. Crowning prosthesis with visible lightsolidfied material made the HA tooth wholesome and nice looking. Implantation and fixation of the HA teeth into the fresh extraction sockets of all the patients were successful.

Biomimetic Hydroxyapatite Coated Titanium Screws Demonstrate Rapid Implant Stabilization and Safe Removal In-Vivo

The early fixation of bone screws after surgical implantation still remains a challenge in the field of traumatology. Whilst hydroxyapatite (HA) coatings are known to enhance the fixation of implants;their removal at a later time-point may be problematic. An HA coating has been developed to demonstrate that both implant fixation and safe removal are feasible in the same design. Accordingly the aim of this study was to compare the In-Vivo performance of thin biomimetic HA coated titanium screws to uncoated counterparts used as control after bilateral implantation in the femoral condyle of 36 New Zealand White Rabbits. The screws were analysed macroscopically, by histology, micro-CT and biomechanically at both two and six weeks post-implantation. The HA coated screws demonstrated excellent biocompatibility. At two weeks the HA coated screws demonstrated a significant increase in removal torque values as well as a strong trend towards higher pull-out forces. In addition histology confirmed a higher degree of osseointegration and direct bone to implant contact. At six weeks no difference in pull-out force and removal torque could be detected. SEM images confirmed the absence of any residual HA coating indicating a fast coating degradation In-Vivo. The low level of removal torque after full osseointegration at 6 weeks supports the feasibility of safe and easy removal of the implant. The HA coating under study appears to offer a unique characteristic of enhanced fixation with a minimal increase in removal torque after full osseointegration. This may be of value in clinical applications where it is necessary to assure both screw fixation and later removal.

Hydroxyapatite-containing PEO-coating design for biodegradable Mg-0.8Ca alloy: Formation and corrosion behaviour

In this study, the biocompatible protective coating was formed using plasma electrolytic oxidation(PEO) on bioresorbable Mg-0.8Ca alloy. The composition of the formed coating was studied using XRD, SEM-EDX analysis, and micro-Raman spectroscopy. The uniform distribution of hydroxyapatite over the thickness of protective PEO-layer was established. Using traditional(EIS, PDP, OCP) and local scanning electrochemical methods(SVET, SIET with H^(+)-selective microelectrode), the level of protective properties of PEO-layer in a biological environment(mammalian cell culture medium, MEM) was determined. It was established that modification of Mg-0.8Ca alloy surface by PEO contributes to a significant increase in the corrosion resistance of the surface layer, making it possible to control the process of material‘s biodegradation. The maximum local electrochemical activity was recorded after 72 h of testing, while for the uncoated sample,intense corrosion degradation was recorded in the first 12 min of exposure to the cell culture medium. Formation of the PEO-coating results in a twofold decrease in the corrosion current density(2.8·10^(-6)A cm^(-2)) and an increase in the impedance modulus measured at a low frequency(1.7·10^(4)Ω cm^(2)) in comparison with the uncoated material(9.5·10^(-6)A cm^(-2);8.1·10^(3)Ω cm^(2)). The mechanism of material bioresorption was established and a model for biodegradation process of Mg-0.8Ca alloy with hydroxyapatite-containing PEO-coating in MEM was proposed. Analysis of these results and comparing with others obtained by various scientific groups indicate the prospects for application of biocompatible PEO-coating on Mg-Ca alloy in implant surgery.

Treatment of intractable orbital implant exposure with a large conjunctival defect by secondary insertion of the implant after preceding dermis fat graft

AIM: To report a procedure and results of a two-stage operation to manage intractable extensive orbital implant exposure with a large conjunctival defect which was difficult to treat with dermis fat grafts due to repeated graft necrosis. METHODS: A retrospective chart review of four patients who had extensive orbital implant exposures with large conjunctival defects and had past histories of repeated autologous or preserved dermis graft failures was done. As a first-stage operation, the problematic pre-existing orbital implants were removed and autologous dermis fat grafts alone were performed on the defect area. Four months later, new orbital implants were secondarily inserted after confirmation of graft survival. The size of the conjunctival defects and state of the extraocular muscles were checked preoperatively. Success of the operations and complications were investigated.RESULTS: The mean size of the conjuctival defects was 17.3mm×16.0mm, and the mean time from the initial diagnosis of orbital implant exposure to implant removal and autologous dermis fat graft was 20.8 months. After implant removal and autologous dermis fat graft, no graft necrosis was observed in any patients. Also, implant exposure or fornix shortening was not observed in any patients after new orbital implant insertion. CONCLUSION: The secondary insertion of a new orbital implant after pre-existing implant removal and preceding dermis fat graft is thought to be an another selective management of intractable orbital implant exposure in which dermis fat grafts persistently fail.

Effect of basic fibroblast growth factor(bFGF) on the treatment of exposure of the orbital implants

Objective: To evaluate the efficacy and the indication of basic fibroblast growth factor (bFGF) in the treatment of exposure of orbital implants. Design: Retrospective and observational case series. Methods: We reviewed 41 patients (41 eyes) suffering exposure of orbital implants from Jan. 2000 to June 2006. The study group patients with mild exposure received com-bined treatment with bFGF and antibiotic drops, and while the control group patients with mild exposure were treated with anti-biotic drops only. The study group patients with moderate and severe exposure received combined treatment with bFGF and antibiotic drops, and after 2 months they were subjected to amniotic membrane transplantation, while the control group patients with moderate and severe exposure underwent amniotic membrane transplantation after using antibiotic drops. Observation of the growth of conjunctival epithelium and comparison of the healing rate of the two groups. Results: The healing rates of the mild, moderate and severe exposure study group were 100% and 92.3%. The healing rates of the mild, moderate and severe exposure control group were 55.6% and 66.7% respectively. The difference of the healing rates of the mild exposure study group and the control group was significant (P=0.033). And the difference of the healing rates of the moderate and severe exposure study group and the control group was not significant (P=0.167). Conclusion: bFGF may promote obviously the healing of orbital implant exposure, particularly it can be the first choice for the treatment of mild degree exposure. For the moderate and severe cases, it can be administered before surgical repair to enhance neovascularization and will tend to increase the success rate of surgical repair.

Amniotic membrane transplantation for porous sphere orbital implant exposure

Objective: This study is aimed at describing the clinical outcome of amniotic membrane transplantation for exposure of porous sphere implants. Methods: A retrospective review of consecutive cases of porous sphere orbital implant exposure was carried out. Eight cases were presented between May 2004 and Oct. 2006 (5 males, 3 females; mean age 44.5 years). Six had enucleation and two had evisceration. Exposure occurred in two primary and six secondary. Orbital implant diameter was 22 mm in seven cases and 20 mm in one case. Six patients are with hydroxyapatite and two with high-density porous polyethylene (Medpor) orbital implants. The mean time from implantation to exposure was 1.1 months (range 0.8~2 months). All patients required surgical intervention. Results: The time of follow-up ranged from 3.0 to 28.0 months (mean 16.5 months). Amniotic membrane grafting successfully closed the defect without re-exposure in all of these patients. The grafts were left bare with a mean time to conjunctiva of about 1 month (range 0.8~1.5 months). Conclusion: Exposed porous sphere implants were treated suc-cessfully with amniotic membrane graft in all of patients. The graft is easy to harvest. This technique is useful, dose not lead to prolonged socket inflammation and infection, and it is valuable application extensively.

High density porous polyethylene material (Medpor) as an unwrapped orbital implant

Objective: To introduce the clinical effect among patients who received an unwrapped orbital implant with high density porous polyethylene material (Medpor) after enucleation or evisceration. Methods: Retrospective analysis of a series of 302 patients with anophthalmia who underwent placement of an unwrapped high density porous polyethylene orbital implant. We compared the patients (n=180) who accepted primary implant placement with those (n=122) who accepted secondary implant placement. Parameters evaluated included: age at time of surgery, date of surgery, sex, implant type and size, surgery type, the surgical procedure and technique performed, and complications. Results: The time of follow-up ranged from 2.0 to 58.0 months (mean 32.5 months). A total of 5 of 302 (1.66%) cases had documented postoperative complications. The following problems were noted after surgery: implant exposure, 3 patients (0.99%); implant removed due to orbital infection, 1 patient (0.34%); ptosis, 1 patient (0.34%). There were no significant complications observed in other 297 cases and all implants showed good orbital mo- tility. The clinical effect of primary implant placement is better than that of secondary placement. Conclusion: High density porous polyethylene material can be used successfully as an unwrapped orbital implant in anopthalmic socket surgery with minimal complications. The material is well tolerated, nonantigenic and has low rate of infection and migration.

Clinical Application of Artificial Orbital Implantation with a Turning Implantation Method in 46 Cases

Purpose: To analyze and summarize the application of a turning implantation method in artificial orbital implantation. Methods:Artificial orbital implants were implanted into 46 patients who were willing to accept artificial orbital implantation with a turning implantation method. Results:After the implantation, 46 cases (46 eyes) with HA orbital implants were healed with plump orbits. No ptosis appearance, deformity, or rejection was observed. The implants were qualified in appearance and flexibility. Two cases presented with chemosis and eye grinding pain during the early postoperative period,but these patients recovered after effective treatment.After 6-24 months of follow-up,no patient had artificial implant exposure or abnormal orbital stimulation. Conclusion: The turning implantation method provides a good artificial orbital implantation.

Effects and complications of placement of motility coupling post in porous polyethylene orbital implants

Objective:To investigate the effects and complications of primary and secondary placements of motility coupling post (MCP)in the unwrapped porous polyethylene orbital implant(PPOI)following enucleation.Methods:We investigated 198 pa- tients who received PPOI implantation following the standard enucleation procedure in the First Affiliated Hospital,School of Medicine,Zhejiang University,Hangzhou,China,from 2002 to 2004.These patients were subgrouped into PPOI-only patients (112 cases,received PPOI following enucleation),primary MCP patients(46 cases,received primary placement of MCP during PPOI operation),and secondary MCP patients(40 cases,received secondary placement of MCP 6 months after the initial surgery). Effects and complications among these three groups were compared.Results:The PPOI-only patients took shorter treatment course when compared with other two MCP groups(P<0.001),without significant difference noted between the two MCP groups. However,the two MCP groups had better prosthetic motility than PPOI-only group(P<0.001),without significant difference between the two MCP groups.In the early stage,2 eyes in the PPOI-only group and 1 eye in the primary MCP group had PPOI infection.In PPOI-only group,3(2.68%)eyes had PPOI exposure,which occurred after fitting the prostheses;4 eyes(8.70%)in primary MCP group and 1 eye(2.50%)in secondary MCP had PPOI exposure,which occurred before fitting the prostheses.After prosthesis was fit successfully,the excessive discharge and granuloma were 33.9%and 1.79%in PPOI group-only,53.3%and 8.9%in primary MCP group,and 52.5%and 7.5%in secondary MCP group,respectively.Conclusion:Both primary and sec- ondary placements of MCP into the PPOI following enucleation can help patients to obtain desirable prosthetic motility,but may be associated with more complications.The primary placement of MCP with skilled operation in selected patients is more rec- ommendable than secondary placement.

Clinical analysis of hydroxyapatite orbital implantation after ocular trauma in 211 cases

客观：评估治疗学的效果和复杂并发症 ofhydroxyapatite (哈) 在损伤相关的手术以后的病人上的轨道的培植。方法:回顾的分析由 211 个盒子( 211 只眼睛)制造了经历了哈轨道在损伤相关的 enucleation 或取出内脏以后植入放置包括取出内脏和主要 HAimplant 放置的 68 个盒子， enucleation 的 77 个盒子并且哈植入与 multi-windowedsclera 包的放置， enucleation 的 66 个盒子并且哈没有包植入放置。所有盒子被跟随在上面 1-5 年观察治疗学的效果和主要复杂并发症。结果：Fiveof 211 盒子弯屈裂开。有的十个盒子哈植入暴露，包括得严重轨道的感染并且要求的 1 个盒子哈植入移动。由三个外科的方法的 implants 暴露发生从 1.30% ～ 10.06% 并且平均 4.74% 。重要差别从三个方法在迟了的暴露发生和全部的发生被发现(χ ~ 2 =13.372， P 【 第 0.01a χ ~ 2 = 7.540， P 【 0.05 ) 。二个盒子有更低的穹隆的收缩。眼球陷入在方法 1 对待的 1case 发生了并且被植入多孔的聚乙烯(Medpor ) 改正板进轨道的底部。在 210 种情况中，人工的眼睛移动了很好，化妆结果是令人满意的。结论：不同外科的方法有他们的自己的优点和 disadvantage.Enucleation 和放置哈植入与 multi-windowed 包了巩膜支持了更少复杂并发症比其它。

The EffectofLocally Im planted Com plexes of Adriam ycin-Hydroxyapatite Com plexes on Tum or —— Study of A NewAlternative Treatm entfor Hepatic Cancer

A new targeting anticancer system was prepared by using hydroxyapatite particles (2 mm in diameter) as carrier material and adriamycin as anticancer agent. The adsorption and release properties of the complexes were assayed by fluorometry in vivo and in vitro and the curative effect on W 256 sarcoma of rat was observed. The results showed that one particle of hydroxyapatite could adsorb approximately 0.08 mg adriamycin and they can maintain a steady and slow release of adriamycin from hydroxyapatite for one month. When hydroxyapatite adriamycin complexes were implanted into the liver of rat, liver adriamycin concentration at the implanted region was obviously higher than that achieved by injection of adriamycin solution. The locally implanted complexes obviously inhibited the growth of subcutaneous implanted tumor of rat, and increased the survival rate of rat with implanted liver tumor.

Hydroxyapatite/β-tricalcium Phosphate Composite for Guiding Bone Tissue Growth into a Titanium Tube in 8 mm Dog Tibia Cavity Defects

We developed a fixation method and evaluate bone regrowth in the cavities of a Ф4 mm× 8 mm titanium（Ti）tube through porous hydroxyapatite（HAP）/β-tricalcium phosphate（β-TCP）composite filling（group A）,chitosan/calcium phosphate composite filling（group B）,and HAP particle modification（group C）.After 2 and 5 months of implantation in dog tibia defects,new bone formation in the three groups was studied by histology and histomorphometry.Group A displayed the most bone regenerated area in both 2 and 5 months post-operation.The chitosan/calcium phosphate composite in group B mostly degraded 2 months after implantation,leading to fibrous tissue invasion after 5 months.By contrast,less bone formation was observed in group C.These results indicated that filling the cavities of metalprostheses with a porous HAP/β-TCP composite can be used for stable long-term fixation in clinicalsettings.

In Vivo Evaluation of Functionalized Biomimetic Hydroxyapatite for Local Delivery of Active Agents

This study was carried out to investigate the biological response in vivo to biomimetic hydroxyapatite implant coatings functionalized with bisphosphonates and bone morphogenetic proteins. The functionalization was carried out by a simple soaking procedure in the operating room immediately prior to surgery. Cylindrical titanium samples with and without coatings were implanted in the distal femoral epiphysis of sheep and retrieved after 6 weeks. The histological analysis proved that all samples were integrated well in the tissue with no signs of intolerance. Fewer osteoclasts were observed in the vicinity of bisphosphonate-functionalized samples and the bone was denser around these samples compared to the other samples. Samples functionalized with bone morphogenetic protein induced more bone/implant contact but showed a more inconsistent outcome with reduced bone density around the samples. This study demonstrates a simple method to functionalize implant coatings, which provides surgeons with an option of patient-specific functionalization of implants. The observed biological impact due to the delivery of active molecules from the coatings suggests that this strategy may also be employed to deliver antibiotics from similar coatings.

Antibacterial hydroxyapatite coatings on titanium dental implants

Titanium and its alloys are often used as substrates for dental implants due to their excellent mechanical properties and good biocompatibility.However,their ability to bind to neighboring bone is limited due to the lack of biological activity.At the same time,they show poor antibacterial ability which can easily cause bacterial infection and chronic inflammation,eventually resulting in implant failure.The preparation of composite hydroxyapatite coatings with antibacterial ability can effectively figure out these concerns.In this review,the research status and development trends of antibacterial hydroxyapatite coatings constructed on titanium and its alloys are analyzed and reviewed.This review may provide valuable reference for the preparation and application of high-performance and multi-functional dental implant coatings in the future.