重硅油在复杂性视网膜脱离手术中的应用

微创玻璃体手术的快速发展,为视网膜脱离的患者带来福音.许多以前无法治疗的复杂性视网膜脱离得到解剖复位,术后视力得以提高.良好的玻璃体替代物对玻璃体手术的疗效及技术的改进具有非常重要的意义.目前临床上常用的硅油和长效气体( C3F8)比重都比水小,对下方视网膜脱离顶压不足,而且术后患者要保持俯卧体位.重硅油比重比水大,可以对下方视网膜产生有效顶压.本文就重硅油的理化性质、临床应用、治疗效果及并发症等作一简要综述.     

重硅油在眼科临床中的应用

重硅油作为一种新的暂时性玻璃体替代物，较普通硅油对下方视网膜裂孔的顶压有明显优势，在国外已经应用于临床。本文对重硅油的产生、物理化学性质、眼内填充的适应证、临床疗效及其填充术后并发症作一综述。     

玻璃体替代物在玻璃体视网膜手术中的应用进展

玻璃体手术是治疗视网膜脱离的重要手术方式之一,玻璃体替代物的产生和发展扩大了玻璃体视网膜手术的适应证并提高了手术疗效.目前临床应用的玻璃体替代物有膨胀气体、硅油、重硅油、全氟化碳液体、半氟化物等.本文就玻璃体替代物的理化性质、实验室研究,临床应用等做一综述.     

玻璃体切除,全氟丙烷气体或硅油填充治疗复杂性视网膜脱离

目的连续性总结复杂性视网膜脱离的玻璃体视网膜手术中应用膨胀浓度C3F8气体或硅油作术后玻璃体填充物的临床作用。方法回顾性分析1994年7月～1995年12月一年半中复杂性视网膜脱离94眼连续资料，主要手术操作是保留晶体的玻璃体切除、环扎、注C3F8。随访时间平均5．1月。治愈标准是气泡吸收后视网膜复位。在一些往C3F8失败眼选用硅油填充。结果94眼总复位率80．85％；单独C3F8作玻璃体填充物的治愈率65．91％；21眼进行硅油填充术，复位率85．71％，其中15眼是辅助C3F8失败后改作硅油，6眼在手术初衷就拟硅抽治疗。手术后视力大于0．02在C3F8眼是79．31％（46眼），硅油是61．11％（11眼）。术后眼压一过性升高（41．49％）和以晶体后囊下混浊开始的白内障（34．18％）依然是主要的并发症。结论比较前期临床报道，C3F8辅助治疗复杂性视网膜脱离的治愈率一致，可能与处理基础部玻璃体前部PVR时受到晶体的限制有关。对注气失败眼选用硅油作永久性玻璃体填充物保持视网膜复位是可行的方法，对有晶体眼作玻璃体手术而言，C3F8的术后视功能恢复比硅油好，但统计学上无意义。     

重硅油在玻璃体视网膜手术的应用

下方视网膜是许多玻璃体视网膜病的好发部位,由于比重等原因,普通硅油对下方视网膜疾病的应用效果存在一定局限性。目前研究证明重硅油对下方视网膜疾病的治疗有其独到之处,本文就目前研制的数种重硅油的理化特性、应用疗效和研究进展作一介绍和比较。     

全氟己基辛烷作为长期玻璃体替代物眼组织耐受性的实验研究

目的了解全氟己基辛烷(F6H8)作为长期眼内填充物的眼组织耐受性情况。方法玻璃体切割及玻璃体联合晶状体切割后的兔眼内分别注入F6H8、硅油和12?F8,进行临床观察并分别于术后4,8,12周行光镜和透射电镜检查。结果未保留晶状体眼术后均出现角膜水肿及血管翳形成,硅油组及F6H8组可见角膜后膜形成以及房角关闭。硅油组保留晶状体眼术后出现晶状体后囊下混浊。F6H8注入后玻璃体腔内可见到白色雪片状沉积物形成。F6H8注入后4周起下方视网膜光感受器内节线粒体出现肿胀,硅油组术后12周及12?F8组术后4周上方视网膜可见类似改变。F6H8组术后8、12周下方个别视网膜光感受器外节盘膜可见限局溶解。结论作为长期玻璃体替代物,兔眼晶状体及视网膜对F6H8的耐受性良好,但进入前房会引起严重的角膜、房角改变。     

新一代重硅油Oxane HD、Densiron 68和HWS46—3000的比较

相对于传统硅油，比水重的硅油在理论上具有许多优势，尤其是在伴有增生性玻璃体视网膜病变的下方视网膜脱离的治疗中。近年，三种新一代的重硅油，Oxane HD，Densiron68和HWS46-3000开始应用于临床，已显示出较好的眼内耐受性，提高了手术成功率，为临床治疗难治性视网膜脱离增添了有用的工具。本文对这三种重硅油的物理性质、临床疗效和术后并发症等进行比较，逐一论述。     

玻璃体替代物的研究进展

复杂的玻璃体视网膜手术中,常常需要玻璃体替代物支撑玻璃体腔、维持眼内压.气体、膨胀气体、全氟化碳液体、硅油是现代玻璃体视网膜手术中常用的玻璃体替代物,胶原、透明质酸、水凝胶等被尝试用作长期的玻璃体替代物.理想的人工玻璃体一直是研究的热点.本文就目前应用的以及仍处于实验阶段的玻璃体替代物进行综述,根据其功能、构成及特性进行分类,并讨论它们的临床应用及优缺点,同时定义理想人工玻璃体的标准.     

兔视网膜对硅油RMN3耐受性的研究

临床上经常使用硅油作为长期玻璃体腔填充剂的主要原因是由于其良好的生物相容性,但其密度低于水,对下方视网膜的顶压不足,易在该处形成增生性玻璃体视网膜病变;而比重大于水的全氟化碳液(PFCLs)和部分氟化烷对视网膜具有明显的毒性不适合长期填充眼内[1-4].     

重硅油在严重眼外伤玻璃体手术中的应用

目的探讨重硅油作为眼内填充物治疗严重眼外伤的临床应用。方法对严重眼外伤12例（12眼）进行了玻璃体切除联合重硅油填允。一类是因为眼内异物伤异物位于（损伤）下方视网膜或后极部者共8例。另一类是眼外伤引起下方视网膜脱离增生者共4例。均经闭合式玻璃体切除手术,术中根据病情需要进行异物摘出、剥膜、重水、激光、气-液交换等,最后,行重硅油填充。结果均于术后3个月行硅油取出。所有患眼视网膜全部平复,裂孔封闭、瘢痕稳定。结论重硅油对治疗下方复杂性异物伤和外伤性视网膜脱离有明显疗效。     

Erbium: YAG-Laser Vitrektomie Temperaturmessungen in unterschiedlichen Austauschmedien

BACKGROUND: The erbium:YAG laser has the potential of being used routinely for vitrectomy because of the excellent quality of liquefying vitreous structures and the low vacuum forces required. However, the use of silicone oil and perfluorocarbon may lead to unwanted temperature increases in the microsurgery probe. The aim of this work was to investigate this side effect. MATERIALS AND METHODS: Different replacement materials such as water, methocel, silicone oil and perfluorocarbon were used in a simple eye model. The temperature increase during laser application was measured by means of thermocouples. The maximum temperature increase and time decay were derived with and without aspiration from these time-resolved measurements. The average power at the distal end of the microsurgery probe was chosen to be 1 W. RESULTS: The temperature increase with aspiration in water was found to be significantly smaller than all other replacement materials. Interruption of aspiration leads to a critical temperature increase of approximately 14 K; however, this increase occurred very slowly (decay time 200 s). A comparable result could be observed for methocel, which was used to simulate condensed vitreous structures. In perfluorocarbon and silicone oil we measured a far higher increase in temperature of up to 130 K within a few seconds. Furthermore, small remnants of carbonized materials can be seen in the microsurgery probe after laser application. CONCLUSIONS: The temperature increase during erbium:YAG laser vitrectomy in water can be considered to be harmless for other intraocular structures. However, insufficient aspiration or increased vitreous condensation leads to increased temperature in the microsurgery probe. Our results demonstrate that the use of erbium:YAG laser vitrectomy in materials such as silicone oil or perfluorocarbons is contraindicated.     

A new, heavier-than-water silicone oil: a solution of perfluorohexyloctane in polydimethylsiloxane

PURPOSE: To pre p a re and explore new solutions of semifluorinated alkane in silicone oil, which have a specific gravity slightly higher than silicone oil and vitreous fluid (referred to in the following as heavier-than-water silicone oils (HWSs), and to investigate, in vitro, whether HWSs can be used to plug retina holes, while allowing dehydration of the subretinal space. METHODS: HWS solutions were pre p a red with silicone oil 5000 and perfluorohexyloctane (F6H8). The stability was investigated under different conditions. The viscosity was determined by means of a capillary viscometer. The surface and interface tension were measured using the ring method. RESULTS: HWSs are insoluble in an aqueous medium. Densiron(R)68 (HWS 1.06) is a transparent homogeneous liquid which is slightly heavier (1.06 g/cm3) than water and has a refractive index close to that of vitreous liquid. Densiron68 (HWS 1.06) has a low viscosity (1480 mPas) and interface tension (40.82 mN/m), making it an effective tamponade in the surgical treatment of an inferior detached retina. In addition, the interfaces between Densiron68 and other perfluorocarbon liquids are clearly visible. However, the interface layer between Densiron68 and water is not clear. Finally, all HWSs are stable over the long term at ambient temperatures, as well as physically and thermally resistant. CONCLUSIONS. Due to its physiochemical properties, Densiron68 could meet the requirements for a heavier-than-water tamponade.     

糖尿病视网膜病变玻璃体切除术后玻璃体出血的临床分析

目的 探讨糖尿病视网膜病变(DR)玻璃体切割手术后玻璃体积血的原因，处理措施以及对预后的影响。 方法 回顾性分析98例DRⅣ期患者122只眼行玻璃体手术治疗后发生玻璃体积血25只眼的临床资料。 结果 玻璃体切割手术后发生玻璃体积血占本组玻璃体切割手术患者的20.5%。积血发生在手术后1周内者8只眼，1周至1个月者6只眼，1个月以上者11只眼。25只眼中C₃ F₈填充眼占31.1%,硅油填充眼占6.1%；空气填充眼占33.3%；灌注液填充眼占26.3%。视网膜周边部新生血管增生9只眼。3只硅油填充眼中2只眼积血自行吸收，1只眼局部形成视网膜前膜，在硅油取出同时行前膜剥除；22只非硅油填充眼中6只眼积血自行吸收；2只眼积血加重，但未及时处理，1只眼发生新生血管性青光眼，1只眼广泛玻璃体视网膜增生脱离，视力无光感；14只眼观察2周积血无吸收后进行了再次手术治疗，12只眼1次手术处理后未再积血。随访结束时，视力无光感者3只眼，手动者2只眼，数指～0.1者10只眼，0.3及以下者4只眼，0.3以上者6只眼。 结论 DR玻璃体切割手术后发生玻璃体积血的患者多数有周边部新生血管增生，经过及时手术治疗，预后较好。 (中华眼底病杂志,2007,23:241-243)     

Silicone oil particles trapped in the subretinal space: complications after substitution of the vitreous

Silicone oil particles trapped in the subretinal space, following total replacement of the vitreous by oil, were found in the aphakic eye of a 51-year-old man. The eye had been operated on two times for retinal detachment in other institutes which resulted in a grade D-1 proliferative vitreoretinopathy. The silicone particles resembled beads and were slightly mobile among subretinal strands by changing the eye position. The particles freely moved into the vitreous cavity through a retinotomy site and were removed with the silicone from the vitreous cavity because of ocular pain. Subconjunctival granulation was removed and histological examination showed silicone oil particles in the vitreous cavity, and cellular infiltration.     

A theoretical study of the effect of silicone oil on the electroretinogram

A model of the electroretinogram useful for determining volume conductor effects was used to determine quantitatively the postvitrectomy effect of silicone oil on the ERG. The electrical conductivities of the structures of the eye, the frequency content of the ERG, and the percentage of silicone oil along with the remaining vitreous were incorporated in the model. The result was that it was not until at least 50% of the vitreous was replaced with silicone oil that there was a small reduction of the electroretinogram; this reduction increased nonlinearly as the percentage of silicone oil in the vitreal cavity increased. According to the model, if the vitreous replacement were large, little, if any, of the ERG would be measured even if the retina were quite functional.     

Pachometry before and after vitrectomy with silicone oil injection.

PURPOSE: To evaluate differences in central corneal thickness (CCT) before and after vitrectomy with injection of silicone oil as vitreous substitution material in order to determine whether silicone oil causes more frequent and/or pronounced corneal decompensation than other substitution materials. METHODS: CCT was measured by ultrasonic pachometry in 42 eyes. 25 eyes received injection of silicone oil and 17 eyes C3F8, atmospheric air or saline. Measurements were performed 24 hours pre operatively, during anaesthesia pre operatively and 24 hours, 48 hours and five months post operatively. RESULTS: A progressive central corneal thickening could be demonstrated in both groups. Eyes which received silicone oil showed maximum CCT increase of 0.083 mm (14.1%) 48 hours post operatively. At follow-up CCT had decreased to baseline value in both groups. Silicone oil did not induce CCT changes that were significantly different from those induced by other substitution materials. CONCLUSION: Silicone oil injection in detachment surgery induces reversible corneal decompensation to the same degree as other substitution materials within the first five months post operatively.     

Pharmacokinetics of intravitreal 5-fluorouracil prodrugs in silicone oil: experimental studies in pigs

PURPOSE: To examine the in vivo pharmacokinetics of intravitreal 5-Fluorouracil (5-FU) following tamponade with 5-FU prodrug silicone oil formulations. METHOD: Two different alkoxycarbonyl 5-FU prodrugs denoted C12 and C18 were synthesized and formulated as silicone oil suspensions. A total of 26 pigs underwent conventional three-port lens-sparing pars plana vitrectomy. Approximately 1.6 ml of the prodrug-silicone oil formulation was placed in the vitreous cavity. Operated eyes were enucleated between 20 min and 168 hours postoperatively, and analysed for their content of free 5-FU by high performance liquid chromatography. RESULTS: With the C12 prodrug silicone oil formulation, the concentration of free 5-FU in the vitreous water phase 1 hour after surgery was 3.30 +/- 1.62 microg/ml. After 4 hours this concentration had declined to 1 microg/ml. With the C18 prodrug, the concentration of free vitreal 5-FU never reached 1 microg/ml during the 7 days these experiments lasted. A mathematical model is presented that can explain the measured data if the clearance of 5-FU from the vitreous water phase follows first order kinetics with a half-life of 20 min. CONCLUSION: These experiments, and the model analysis, suggest that the elimination half-life of 5-FU in the vitreous cavity of a vitrectomized, silicone oil-filled eye is very fast. The model analysis indicates that an alkoxycarbonyl 5-FU prodrug with a specific release rate constant of 10.7 microg/square root h cm(2) can maintain an intravitreal 5-FU concentration above 1 microg/ml for 5 days in the porcine eye.     

Usefulness and limit of silicone in management of complicated retinal detachment

Among various substances used for intraocular tamponade in the treatment of vitreous opacity and complicated retinal detachment, silicone oil is superior to hyaluronic acid or sulfur hexafluoride. Its low gravity and hydrophobic nature permit good tamponade effect to be obtained and its high transparency allows us to detect remnant vitreous traction in the far periphery and/or retinal tears. Furthermore, preretinal membrane can be peeled off easily after silicone oil removal. The hydrophobic nature of silicone prevents clouding due to postoperative hemorrhage and fibrin reaction. It should also be stressed that intravitreal silicone oil suppresses iridial rubeosis or prevents its development. However, the use of silicone has limitations, since it gives rise to various complications that include pupillary block glaucoma, secondary glaucoma, cataract formation and corneal complications including band-shaped keratopathy. Pupillary block in aphakic eyes can be prevented by placing peripheral iridectomy at the 6 o'clock position, since silicone is lighter than water. After silicone injection, glaucoma is more often seen in diabetic aphakic eyes than in phakic or nondiabetic eyes. On the other hand, corneal complications were less frequent in diabetic than in nondiabetic eyes; in nondiabetic eyes the complications were more frequent in aphakic than in phakic eyes. Due to possible complications, silicone should be removed after a certain follow-up period, during which time detection and management of the causes of redetachment of the retina are possible due to the high transparency of silicone.     

Refractive changes from use of silicone oil in vitreous surgery

When silicone oil fills the vitreous cavity of the phakic eye or the entire aphakic eye, the refractive correction can be expected to change by 5-9 diopters and sometimes as much as 14 diopters. Aphakic eyes become less hyperopic when filled with silicone oil, whereas phakic eyes become more hyperopic when the vitreous cavity is filled with silicone oil. Previously emmetropic aphakic eyes that are filled with silicone oil have only 4-6 diopters of hyperopia, whereas the same eyes have 10-12 diopters of hyperopia before insertion or after removal of silicone oil. Phakic eyes develop 5-7 diopters of hyperopia when the vitreous cavity is filled with silicone oil, and this puts them in the same range as the silicone oil filled aphakic eyes. High myopia, incomplete silicone oil filling, and several other factors influence the final optical outcome. The vitreoretinal surgeon must anticipate significant changes in refractive error when silicone is introduced into an eye or removed from the eye. Careful retinoscopy and refraction is essential for obtaining optimal vision in these patients.