Experiment Study And Research-Development Of Cooling System For Tip Of Phacoemulsification In Operating

Background and ObjectiveAs a developing country, China always has a relatively high incidence of age-related cataract. The fast-pace progresses of cataract surgery have greatly improved the visual outcomes and have also changed patients' criteria for satisfactory operations. Nowadays phacoemulsification has already become a main-stream technique in cataract surgery and been carried out widely because of its more advantages than that of extracapsular cataract extraction(ECCE), such as less surgical trauma, lower incidence of complications and faster rehabilitation of postoperative visual function and so on. Although fast paces of progress in cataract surgery have made the present phacoemulsification simple, speedy and satisfying, cataract surgeons never spared their efforts in trying to develop new procedures which endow cataract surgeons with the ability to extract cataract through microincisions with low incidence of wound burn and high efficiency. The thermal wound of incision, over a long time, have been a prominent and thorny problem during phacoemulsification surgeries, which can make tissue around incision area contracted and lead to the surgery-induced astigmatism. Bimanual rmcrophacoemulsification(microphaco) is a newly developed procedure which derives from the conventional phacoemulsification (phaco). By removing silicone sleeves of the phaco tips, incision were shortened to 0.9～1.4mm, which is no more than half of the incision length of conventional phacoemulsification.In this project, we intended to evaluate the safety and efficacy of using the self-made cooling system for the tip of phacoemulsification during operation in decreasing the thermal wound of incision by comparing and investigating the state of temperature of incision at different ultrasound times (0s,25s,50s,75s,90s) during phacoemulsification surgery to rabbits and the state of edematous of corneal area around the incision after operation.Materials and MethodsSTORZE Protegéphaco machine with 70% continuous power mode was used during operation of both the conventional phacoemulsification and cooling phacoemulsification. 60 black New Zealand rabbits(120 eyes)were randomly divided into 2 groups(A group and B group), 60 eyes in every group. A group was the control group for the conventional phacoemulsification, B group was the experiment group for the cooling phacoemulsification which used self-made cooling system for the tip of phacoemulsification and received bimanual phacoemulsification microincision cataract surgery (MICS). At different ultrasound time of 0s, 25s, 50s, 75s, 90s in operating, the temperature of incision were measured and recorded using a type K thermocouple digital thermometer, the states of edema of corneal area around the incision after operation were investigated respectively. The data of the experiment were analyzed by SPSS 13.0.Results(1) the state of temperature of incision at the different points of ultrasound timeThe temperature of incision measured during the phacoemulsification surgery for B group were strikingly lower than the A group at the different points of ultrasound time. The between-group difference was statistically significant respectively(P< 0.01). The temperature(℃) of incision measured during at different ultrasound time of 0s, 25s, 50s, 75s and 90s were respectively 18.1±0.89, 23.41±1.07, 35. 8+1. 11, 44.72±1.88 and 51.98±1.51 in group A; 8.17±0.79, 10.33±0.75, 13.8±1.04, 16.17±0.93 and 17.90±1.10 in group B.When pressing the incision wall with pressure to the tip of phacoemulsification, temperatures of the location reached 71.6℃and 23.2℃in control group(A group) and experiment group(B group) respectively.(2) The state of edema of corneal area around the incision after operatingThe extent and quantity in edema of corneal area around the incision for B group was strikingly lower than the A group after operating. The between-group difference was statistically significant (P< 0.05). The rate of edema of corneal area around the incision was 100% in A group, 15% in B group.Conclusions(1) Under the continuous power mode of conventional phacoemulsification, the self-made cooling system for tip of phacoemulsification could make the tip produce much less heat at the tissue incision during operation and was relatively safer from this aspect, which was effective both in preventing incision from thermal wound and maintaining the excellent ability of conventional phacoemulsification in handling hard cataract.(2) Bimanual phacoemulsification MICS with the self-made cooling system for tip of phacoemulsification could make incision shorten to 1.7mm, which was less traumatic and well effective to eyes.(3) Bimanual phacoemulsification MICS with the self-made cooling system for tip of phacoemulsification could stabilize anterior chamber during operation effectively.(4) Compared to conventional phaco, bimanual phacoemulsification MICS with the self-made cooling system for tip of phacoemulsification was a microtrauma technique worth being popularized in cataract surgeries.(5) The self-made cooling system for tip of phacoemulsification, however, presently needed to be modified further in the efficiency of operation, the workmanship of appliances and the flexibility.