方法：回顾分析在我院行扭动模式下超声乳化白内障摘除联合人工晶状体植入手术的白内障患者247例320眼，根据术中碎核方式，分为改良预劈核组和常规乳化拦截劈核组。其中改良预劈核组省略水分离步骤，使用加长劈核钩从6：00位前囊膜下贴囊袋内壁探入囊袋与晶状体间隙，绕过晶状体赤道，待劈核钩前端至晶状体后极时向上用力与进入前房的超声乳化头在不使用超声的状态下挤切劈裂晶状体核为两半，转核、并反复多次劈核。对照组用常规拦截劈核法。术前记录包括最佳矫正视力、角膜内皮计数，术中记录平均超声能量(AP)、实际超声乳化时间(U/Stime)、平均累积能量符合参数(AECP)、前房BSS灌注量和手术并发症，观察术后1wk角膜水肿的情况和角膜内皮细胞计数。

结果：将两组同级核硬度的亚组进行比较，改良预劈核组的平均超声能量、实际超声乳化时间、累积超声能量时间和前房BSS灌注量、1wk角膜内皮丢失率均低于拦截劈核组(P<0.05)。

结论：使用改良预劈核扭动模式白内障超声乳化的方法可提高手术超声能量利用效率、减少手术中前房灌流量，并进一步降低白内障超声乳化手术对患者角膜内皮的损伤。

METHODS: Retrospectively analyzed 247 patients(320 eyes)with ozil phacoemulsification and intraocular lens implantation surgery. The 247 patients were randomly divided into two groups. The two groups were given different chop method during the surgery: improved pre-chop and traditional stop and chop. The improved pre-chop group were canceled water separation steps, the ultra-long chopper were entered into the capsular bag under the rim of continuous circular capsulorhexis, by passed the intraocular lens equator then reversed the hooker upward against the posterior pole of lens and cracked the nuclear into half with the phacoemulsification hand pieces extruding the nuclear from above downward without using energy, then rotated the nuclear and repeated the chop step. The control group used the traditional stop and chop technique. Pre-surgery recording included the best-corrected visual acuity(BCVA)and corneal endothelial cell counting. Average power(AP), real ultrasound phacoemulsification time(U/Time), accumulated energy complex parameter(AECP), BSS perfusion amount and complications were recorded. And the corneal edema and corneal endothelial cell counting were observed at one week post the surgery.

RESULTS: Compared the sub-group of two groups with the same hardness of nuclear, the AP, U/Time, AECP and the BSS perfusion amount of the improved pre-phaco group were lower than the stop and chop group(P<0.05)with significant difference. Also the lose rate of corneal endothelial cell of the improved pre-phaco group was lower than the stop and chop group(P<0.05).

CONCLUSION: Using the improved pre-phaco method in the ozil phacoemulsification cataract surgery could raise the energy utilization efficiency, decrease the BBS perfusion amount during the surgery and further lower the injury to the corneal endothelial cell brought by the phacoemulsification surgery.