直肌内血管显微分离方法的实验研究

目的：探讨眼直肌内睫状前动脉（ACAs）显微分离术的方法和技巧及应用此方法在一眼同时行4条直肌手术的安全可行性。方法：对健康成年杂种犬10只16只眼行直肌内睫状前血管显微分离术。其中8只眼行直肌联结术（Jensen术式），8只眼行肌肉转位术（Hummelsheim术式），术后观察眼前段反应三个月。结果：垂直肌的血管较水平肌粗，易分离。ACAs在直肌内的数目存在变异。每例手术均成功分离并保留了大多数ACAs，两种术式术后均未发现眼前节缺血（ASI）。结论：直肌内血管显微分离术是一种安全可行的显微手术方法，可使累及多条直肌的复杂斜视手术一次完成，避免或减少了ASI的风险。     

直肌内血管显微分离术方法的实验研究

目的探讨眼直肌内睫状前动脉(ACAs)显微分离术的方法和技巧及应用此方法在一眼同时行4条直肌手术的安全可行性.方法对健康成年杂种犬10只16只眼行直肌内睫状前血管显微分离术.其中8只眼行直肌联结术(Jensen术式),8只眼行肌肉转位术(Hummelsheim术式),术后观察眼前段反应三个月.结果垂直肌的血管较水平肌粗,易分离.ACAs在直肌内的数目存在变异.每例手术均成功分离并保留了大多数ACAs,两种术式术后均未发现眼前节缺血(ASI).结论直肌内血管显微分离术是一种安全可行的显微手术方法,可使累及多条直肌的复杂斜视手术一次完成,避免或减少了ASI的风险.     

血管显微分离在眼外肌手术中应用的临床研究

目的斜视矫正手术有时需要在一只眼上同时离断3条或3条以上直肌,因而过多地损伤了睫状前动脉,导致眼前节缺血综合征的发生.本课题主要是探讨斜视矫正手术多条眼外肌一次完成的方法.方法本组手术均在局麻下进行,结膜下注射2%利多卡因,做肌止端结膜切口,暴露直肌,显微镜下将延直肌走行的睫状前动脉分离出来,离断肌肉时保留血管.手术量和术式与常规眼外肌手术相同.结果斜视矫正效果:治愈32例(88.89%),好转4例(11.11%).采用彩色多普勒测定虹膜大环术前术后血流流速,差异无显著性.结论应用血管分离术可实现多条眼外肌手术一次完成.眼外肌睫状前动脉血管显微分离术最大限度地降低眼前节缺血发生的可能.减少手术次数,既简化了斜视矫治过程又减轻了病人的痛苦.     

斜视的显微手术治疗初步分析

目的 探讨斜视显微手术治疗的优点。方法 15例水平性斜视患者在显微镜下行斜视矫正术。部分患者行睫状前血管分离术。结果 15例患者术后斜度均在土10^Δ以内，6例出现一过性的复视，一周后复视消失。随访期1～5个月。在15例患者中。有3例因睫状前血管太细放弃分离血管，最后成功保留血管者4例，其余8例未能成功地分离或保留睫状前血管，有的在分离过程中血管破裂，有的在肌肉缝合过程中断裂。结论 斜视的显微手术有着明显的优势，从传统的斜视手术向显微斜视手术过渡是可行的。     

显微技术应用于斜视矫正术的疗效分析

目的探讨显微手术技术应用于斜视矫正术的优点。方法对37例斜视患者在显微镜下进行斜视矫正术,其中5例复杂性斜视行睫状前血管分离。平均随访6个月,对术中、术后并发症及手术效果进行临床分析。结果所有患者均在第一眼位获得理想眼位,术中、术后并发症明显减少,5例复杂性斜视成功分离并保留睫状前血管,减少手术次数。结论在手术显微镜下行斜视矫正术更安全,手术并发症少。     

斜视术中的血管显微分离

用血管显微分离术后徙、截除或转位任何一条直肌而不中断相应的前睫状动脉的血流，避免斜视术对眼前节血流的不良影响，且起到预防眼前节缺血综合征的作用。我们用该方法完成了１６例（２４眼），手术前后均为正常的眼外肌血流图。术后保持了正常的眼前节血循环，发展和熟炼了手术技巧。术后矫正效果与常规斜视手术相同，该手术不影响术后眼位校正     

显微镜下直肌联结术治疗外直肌麻痹13例临床观察

目的 观察显微镜下采用显微技术行直肌联结术治疗外直肌麻痹的手术效果.方法 回顾分析从2005年1月～2007年7月显微镜下行直肌联结术联合同侧内直肌后退矫正13例15眼完全性或近完全性外直肌麻痹的手术效果.随访时间1个月至2年.结果 一次手术后正位7例8眼,4例5眼欠矫＜10°,2例2眼欠矫15°.术后平均外转过中线达11°(5°～20°)大部分病例外观满意,外转功能有不同程度改善,未发现眼前节缺血等并发症.结论 直肌联结联合同侧内直肌后徒术治疗外直麻痹效果理想,显微镜下分离睫状血管降低了眼前节缺血发生的风险.     

睫状前动脉的应用解剖学研究

目的：对睫状前动脉的分支、分布、行程及睫状前动脉与虹膜大环关系进行研究，为眼科斜视矫正手术提供解剖学资料。方法：采用２５只成人眼球，眼动脉进行红色乳胶氧化铅混合液灌注，在手术显微镜下解剖观察；２只新生儿眼球进行墨汁灌注，切厚片观察睫状前动脉的行程、分布。结果：睫状前动脉为眼直肌内主要肌动脉的直接延续。外直肌睫状前动脉１～２条；上、内、下直肌２～３条。出肌处口径：上直肌０．２０２±０．０６３ｍｍ，内直肌０．１６４±０．０６０ｍｍ，下直肌０．２１１±０．０８０ｍｍ，外直肌０．２０３±０．１９４ｍｍ。睫状前动脉出肌处与直肌止点的距离：上直肌８．８２±２．５０ｍｍ，内直肌６．０８±１．４１ｍｍ，下直肌６．６３±２．４５ｍｍ，外直肌１０．１±２．８４ｍｍ。Ｘ线显示各直肌的睫状前动脉均参与虹膜大环的构成。纵向组织切片睫状前动脉为肌动脉延续，沿直肌肌腱表面前行，发支到巩膜，最后终于虹膜大环。结论：睫状前动脉与直肌关系十分密切，是构成虹膜大环的优势血管，在斜视矫正手术中，特别一次手术涉及到多条直肌时，应注意睫状前动脉的保护，防止术后眼前节缺血。     

实验性眼前段缺血综合征的电镜研究

目的探讨眼前段缺血综合征的发生机制和超微病理变化及分离和保留睫状血管对其发生的预防作用。方法将32只成年新西兰白兔随机分为4组，第1组双眼分别切断内外2条水平直肌。第2组双眼分别切断上下2条垂直肌。第3组双眼分别切断上下及内或外直肌共3条直肌。第4组双眼分别切断内外、上下4条直肌。每组动物均在右眼分离保留睫状血管，左眼切断直肌和睫状血管。术后4周取虹膜和睫状体组织电镜检查。结果第1组动物双眼无明显缺血改变，第2、3、4组不保留血管眼有明显甚至严重缺血改变，保留血管眼无缺血改变。结论论证了切断不同的直肌引起的眼前段不同组织的超微结构变化及其与眼前段缺血发生的关系，分离和保留睫状前血管可以有效预防眼前段缺血综合征的发生。     

实验性眼前段缺血综合征的组织病理学研究

目的　观察兔眼实验性眼前段缺血综合征的组织病理学变化 ,及其发生与直肌切断的数目和组合之间的关系 ,以及分离保留直肌睫状前血管是否能预防眼前段缺血综合征的发生。方法　 8只新西兰大白兔分成 4组 ,分别切断内和外直肌、上和下直肌、内和外直肌加一条垂直肌、 4条直肌 ,其中右眼分离保留睫状前血管 ,左眼不分离保留血管。在术后 4周取兔眼的虹膜和睫状体做病理学检查。结果　所有保留血管眼以及不保留血管眼中切断两条水平肌眼未出现明显病理学变化 ,而切断上下直肌以及 3条以上直肌眼出现明显的缺血性病理学变化 ,其中包括 :虹膜上皮细胞及基质水肿 ,睫状体基质出血、白细胞浸润等。结论　单纯切断兔眼两条水平直肌一般不引起眼前段缺血综合征 ,同时切断上下直肌或 3条及以上的直肌则可能引起眼前段缺血综合征 ,虹膜和睫状体表现出一系列的组织病理学变化。分离保留睫状前血管可预防眼前段缺血综合征的发生。     

Preservation of the anterior ciliary vessels during extraocular muscle surgery

Conventional, full-tendon, rectus muscle surgery disrupts the anterior ciliary vessels. This may lead to anterior segment ischemia when the number of interrupted vessels is sufficient to significantly compromise anterior segment blood flow. Clinical observations and histologic studies provide new anatomic information concerning the course of the anterior ciliary vessels in the sub-Tenon's region. These studies demonstrate the feasibility of dissection and preservation of the anterior ciliary vessels during rectus muscle surgery. Dissection and preservation of 35 clinically apparent anterior ciliary vessel groups were attempted on 15 rectus muscles during strabismus surgery. The unplanned vessel destruction rate was 9.5%. Procedures included 12 recessions, 1 resection, and 2 full-tendon transpositions. The possible role of this procedure in the prevention of anterior segment ischemia is discussed.     

Microvascular change of the anterior eye segment after tenotomy in the rabbit

Background: The microvascular changes secondary to anterior segment ischemia following tenotomy of the extraocular muscles have not been studied in the rabbit. Methods: Using scanning electron microscopy of methylmethacrylate ocular microvascular luminal castings, the anterior eye segment vasculature after tenotomy was documented and compared to that after occlusion of the bilateral long posterior ciliary arteries and that in the eyes that were not subjected to any surgical intervention. Results: Five days and 1 week after the surgical intervention with tenotomy, microvascular change secondary to the anterior segment ischemia was not apparent, but 2 weeks after the tenotomy subtle evidence of ischemia such as new vessels in the iris was observed. Seven weeks after tenotomy, marked microvascular change was observed where corneal new vessels arose from the superior perilimbal arteries. In contrast, we found prominent microvascular changes 2 weeks after the occlusion of the long posterior ciliary arteries. Conclusions: Tenotomy of the rabbit eye causes microvascular change similar to that in occlusion of the long posterior ciliary arteries. This result suggests that the anterior ciliary artery of the rabbit contributes blood flow to the anterior eye segment and also has a stronger connection with the long posterior ciliary artery than previously reported.     

Anterior segment ischemia after strabismus surgery with microvascular dissection.

Anterior segment ischemia is a rare but well-known complication of extraocular muscle surgery.(1) Several surgical techniques have been used to prevent this complication in high-risk patients. A number of studies have suggested that microvascular dissection and preservation of the anterior ciliary vessels during strabismus surgery may reduce the risk of ischemic complications. (2-4) We present a case in which anterior segment ischemia occurred despite the use of this vessel-sparing technique.     

Neovascularization in the anterior segment of the rabbit eye by experimental anterior ischemia

PURPOSE: To investigate the effects of anterior ischemia accompanied by neither retinal nor choroidal ischemia on the anterior segment of the eye. METHODS: Both long posterior ciliary arteries in the right eye of 14 rabbits were directly cauterized with an electric coagulator. The eyes were enucleated 1, 2, 4, 7, 9 or 14 days after cauterization, then fixed with 4% paraformaldehyde. Semi-thin sections were studied by light microscopy. Several sections were stained with Griffonia simplicifolia lectin, which bound specifically to mammalian vascular endothelium. Other specimens were examined immunohistochemically for vascular endothelial growth factor (VEGF) protein. The tissue specimens of the first postoperative day were studied for expression of VEGF mRNA by in situ hybridization. RESULTS: Atrophy of the iris and ciliary body was seen after the second postoperative day. Corneal neovascularization appeared after 7 days. Neovascularization on the anterior surface of the iris and in the trabecular meshwork was detected after the ninth postoperative day. The proliferative tissues with newly formed vessels obstructed the iridocorneal angle 14 days after the treatment. There was no histological change in either the retina or choroid. Immunohistochemically, VEGF protein was detected in the epithelial and vascular cells of the iris on the first and fourth postoperative day. Expression of VEGF mRNA was detected in the epithelial cells of the ciliary body on the day following the treatment. CONCLUSIONS: Anterior segment ischemia, when unaccompanied by retinal ischemia, causes neovascularization in the cornea, iris and trabecular tissue.     

Anterior segment ischemia: classification and description in chronic myelogenous leukemia.

A patient with chronic myelogenous leukemia is described who developed anterior segment ischemia after extreme leukocytosis with a resultant increase in the blood viscosity. The patient's signs and symptoms resolved after therapy which normalized the white blood cell count. It is thought that the anterior segment ischemia was a result of sludging of white blood cells in the ciliary arteries. It is important to recognize that anterior segment ischemia can occur as a complication of chronic myelogenous leukemia associated with extreme leukocytosis. A new classification of anterior segment ischemia is given.     

Scanning electron microscopic study on the vasculature of the human anterior eye segment, especially with respect to the ciliary processes

The architecture of the vasculature of the human anterior eye segment was studied by scanning electron microscopy of vascular resin casts. Regarding the major vessels it was found that the perforating branches of the anterior ciliary arteries (ACA) form an anastomozing circle which lies in the posterior portion of the ciliary muscle (intramuscular circle). The ACAs supply the outer and posterior parts of the ciliary muscle, partly the iris, and the peripheral choroid by recurrent ACA branches. The major arterial circle of iris (MACI) which lies more anteriorly is formed mainly by the long posterior ciliary arteries and supplies the inner and anterior portion of the ciliary muscle, the iris and the ciliary processes. The ciliary process vasculature consists of three different vascular territories with discrete arterioles and venules. The first vascular territory which is located at the anterior end of the major processes, is drained posteriorly by venules which pass the ciliary body without greater connections to the venules of the major ciliary processes. The second and third territories comprise the vasculature of the major and minor ciliary processes drained posteriorly by venules which are located at the margin of the ciliary processes. In supravital experiments with human autopsy eyes, a characteristic segment of arterioles supplying the first and second territory was found to be constricted after immersion with epinephrine in a similar way as in cynomolgus monkeys in vivo. Although the general arrangement of the ciliary process vessels is similar to that of the cynomolgus monkey, there are characteristic differences in the size of the territories and in the pattern of the capillary networks. The division of the ciliary process vasculature into three vascular territories may reflect a functional differentiation in the process of aqueous humour production.     

Surgical techniques of strabismus

Improvements in the management of strabismus are largely dependent on making the specific diagnosis and differentiating patterns of strabismus. This finding is especially true in the management of superior oblique paresis because there are various types. Recent observation suggests that superior oblique paresis may be associated with a lax superior oblique tendon and that the cause of the paresis is not always neurogenic. Some authorities have suggested using the traction test of the superior oblique to determine whether the superior oblique tendon is lax. If it is lax, the treatment of choice would be a tightening procedure of the superior oblique such as the superior oblique tuck. Adjustable-suture strabismus surgery has reduced the incidence of repeat operations; however, adapting the procedure to the fornix incision has been difficult. The use of a scleral traction suture that retracts the conjunctiva to expose the muscle suture area has been useful for fornix surgery. The rectus muscles supply circulation to the anterior segment via the anterior ciliary vessels, which are routinely interrupted during strabismus surgery. Various procedures have recently been described to preserve the anterior ciliary vessels, and these procedures will be useful in patients who are predisposed to anterior segment ischemia. In the 1950s, inferior oblique weakening procedures were deemed dangerous and unpredictable. Recent advances in the understanding of inferior oblique physiology and fascial relationships have inspired the development of a new inferior oblique weakening strategy--the anteriorization procedure.(ABSTRACT TRUNCATED AT 250 WORDS)     

Localization of beta receptors in the anterior segment of the rat eye by a fluorescent analogue of propranolol.

A fluorescent analogue of propranolol, 9-AAP, was injected intravenously in order to detect beta-adrenergic receptors in the anterior segment of the albino rat eye. Specific 9-AAP fluorescence was noted along cell membranes of the ciliary epithelium and to lesser extent in the walls of blood vessels in the ciliary processes and episclera at the limbus. The iris showed maximum 9-AAP binding in the region of the sphincter muscle. These data suggest that 9-AAP may label beta receptors in the anterior segment of the rat eye.     

Ultrastructure of the ciliary process vasculature in cynomolgus monkeys

The ultrastructure of the ciliary process vasculature in cynomolgus monkeys is described with transmission electron microscopy. Special attention is paid to a special segment of the anterior arterioles (afferent segment) and to the end of the marginal venule (efferent segment)-vascular structures which have been described as haemodynamically important. The major arterial circle of iris (MACI), the exclusive blood supply of the ciliary processes, has only a one- or two-layered medium. A short distance after the anterior arterioles of the ciliary processes have branched off, these arterioles develop a characteristic segment of about 100 microns in length and which possesses a two-layered medium where prominent special myocytes lie on the adventitial side (afferent segment). Nerve endings with dense-core and large vesicles are closely associated to the vessel wall of these afferent segments. On the 'venous' side of the ciliary process vasculature, the very thin wall of the marginal ciliary process vessel becomes reinforced by a layer of myocytes in a segment which is located in the zone where the marginal vessel bends into the layer of the pars plana venules (efferent segment). Here, the endothelium is substantially thickened and filled with different-sized granules. Nerve endings with clear- and large dense-core vesicles lie around this segment.