直肌睫状前血管的分离和保留对兔眼前段缺血综合征的预防作用

目的　观察兔眼眼外直肌手术中直肌睫状前血管 (ACVs)的分离和保留对预防眼前段缺血综合征 (ASI)的作用。方法　将 32只健康新西兰白兔随机分为 4组 ,每组右眼分离和保留ACVs,左眼去除ACVs。A组 :切断 2条水平直肌 ;B组 :切断 2条垂直直肌 ;C组 :切断内、外直肌和 1条垂直直肌 ;D组 :切断 4条直肌。术前和术后裂隙灯显微镜下观察眼前段的体征 ,测量眼压、房水中总蛋白和乳酸的浓度。术后 4周处死动物 ,光镜和电镜下检查虹膜和睫状体的超微结构。结果 4组中右眼术后均未发生缺血性改变。A组左眼无明显缺血改变 ,B组左眼仅出现轻度缺血的病理学改变。C、D组左眼出现明显甚至严重的ASI体征 ,眼压出现下降趋势 ,C组眼压术前为 (17 2 1± 3 76 )mmHg(1mmHg =0 133kPa) ,术后最低降至 (14 4 8± 3 36 )mmHg(P <0 0 5 ) ,D组眼压术前为 (16 6 8± 2 33)mmHg,术后最低降至 (3 17± 0 92 )mmHg(P <0 0 5 ) ;房水中总蛋白和乳酸的浓度明显增高 ,C组术前分别为(5 0 5 3± 5 0 )mg/L和 (7 5 4± 0 4 7)g/L ,术后分别最高升至 (811 9± 4 4 4 )mg/L和 (11 0 0± 3 5 9)g/L(P<0 0 5 ) ;D组术前分别为 (5 0 4 6± 4 1)mg/L和 (7 17± 1 4 4 )g/L ,术后分别最高升至 (10 2 5 8± 78 3)mg/L和 (8 2 3± 1

The effect of preventing anterior segment ischemia by preservation of anterior ciliary vessels in rabbit

OBJECTIVE: To investigate the effect of preserving anterior ciliary vessels (ACVs) on the prevention of anterior segment ischemia syndrome (ASI) during the surgery of extraocular muscles. METHODS: Thirty-two adult New Zealand white rabbits were randomly divided into four groups. ACVs of the right eyes were preserved among all of the rabbits, and were cut off in all of the left eyes. Group A: internal and external recti were cut off in two eyes; Group B: superior and inferior recti were cut off in two eyes; Group C: internal, external and superior or inferior recti were cut off in two eyes; Group D: all of the recti were cut off in two eyes. All rabbits were observed under slit microscope. The intraocular pressure (IOP), the total protein and lactic acid in the aqueous humor were recorded preoperatively and postoperatively. Eyes were enucleated at the forth week postoperatively to obtain the iris and the ciliary body for histopathologic study and electron microscopy. RESULTS: No signs of ASI were observed in the right eyes of all four groups under the slit lamp and under the light and election microscopes. The IOP and levels of ingredients of aqueous humor (total protein and lactic acid) showed no difference between preoperative and postoperative interval. No obvious ASI was observed in the left eyes of group A. Mild reactions of ASI were observed in the left eyes of group B. Moderate to severe reactions of ASI were observed in the left eyes in group C and group D. The IOP reduced from (17.21 +/- 3.76) mm Hg (1 mm Hg = 0.133 kPa) preoperatively to (14.48 +/- 3.36) mm Hg postoperatively in group C (P < 0.05); and from (16.68 +/- 2.33) mm Hg reduced to(3.17 +/- 0.92) mm Hg in group D. (P < 0.05). The level of total protein and lactic acid in the aqueous humor increased from (505.3 +/- 5.0) mg/L and (7.54 +/- 0.47) g/L preoperatively to (811.9 +/- 44.4) mg/L and (11.00 +/- 3.59) g/L postoperatively in group C, respectively (P < 0.05). In group D, the level of total protein and lactic acid in the aqueous humor increased from (504.6 +/- 4.1) mg/L and (7.17 +/- 1.44) g/L preoperatively to (1025. 8 +/- 78.3) mg/L, (8.23 +/- 1.68) g/L postoperatively, respectively (P < 0.05). There were various histopathological changes under the light and electron microscope in groups C and D. While no obvious ischemic changes were observed in group A. CONCLUSION: Two vertical muscles cut off at one eye simultaneously would produce mild reactions of ischemia, while three or more muscles cut off simultaneously could obstruct blood flow in eyes and induce ASI. Preservation of the ACVs could avoid the occurrence of ASI.