Comparing surgical efficiencies between phacoemulsification systems: a single surgeon retrospective study of 2000 eyes

INTRODUCTION

Age-related cataract is the most common cause of reversible blindness in the world

, with its first successful extraction of a cataract performed by Jacques Daviel in 1747

. In 1967, Charles Kelman

introduced phacoemulsification, a technique that uses ultrasonic waves to break down the cataract. Surgical extraction of the natural lens has progressed along time, leading to more than 20 million cataract surgeries performed worldwide each year

.Phacoemulsification is the gold standard for cataract surgeries globally and breakthroughs in different systems, ultrasound tips and sleeves continue to improve surgical efficiencies and results

.

Parameters for phacoemulsification for the active fluidics dynamic system were set as follows: IOP 65-70 mm Hg, vacuum 350-575-400 mm Hg, aspiration flow rate 38-52-41 mL/min and 20%-75% torsional amplitude. Fluid parameters for the gravitybased system were vacuum limit 100-450 mm Hg, aspiration flow rate 40 mL/min, bottle height 70-90 cm. Ultra sound parameters were set at 20%-80% of torsional amplitude.

Changes in aspiration and infusion flow rates can cause fluctuations in intraocular pressure (IOP)

. Wide fluctuations of IOP may cause the anterior chamber to collapse and damage the cornea, the iris, and the lens capsule

. Phacoemulsification systems such as active fluid dynamics and gravity-based fluidic, are used to perform cataract surgeries. Active fluid dynamics systems apply or release bag pressure in response to varying irrigation, to maintain a target IOP during surgery despite varying aspiration flow rates

. Maintaining anterior chamber stability and decreasing fluctuations in IOP is essential to reduce complications and improve postoperative outcomes

. A study conducted by de Giacinto

demonstrated a statistically significant transient increase in IOP during femtosecond laser-assisted cataract surgery. Even though IOP values decreased and came back to preoperative values at 1d postoperatively, sudden increases of IOP can be dangerous for the ocular structures

.

多么完美的愛情故事，受傷的少年初遇探病的少女，雖然動機不太清楚。但是我們這些熟讀武俠小說的老油條，對這些充滿酸臭的愛情故事，還是相當熟悉的。即便我們知道丁珰是認錯人了，但這個并不重要。認錯個把人算什么，上錯花轎都能嫁對郎呢。我們的狗雜種同志，為人淳樸，心地善良，武功深厚，當是江湖中難得一見的主角，丁珰姑娘此時出現(xiàn)，適逢其會，郎才女貌，妖怪都反對不了。

The purpose of this study was to compare intraoperative surgical efficiency metrics between two phacoemulsification systems under similar conditions as previous studies comparing phacoemulsification systems failed at comparing surgical efficiencies using different parameters, phacoemulsification tip and sleeve. CDE and aspiration fluids were compared between an active fluidics dynamic system and a gravity-based fluidic system configured with the same ultrasound tip and sleeve.Surgery was performed by a single surgeon to 2000 eyes,during routine phacoemulsification extraction of cataracts graded with the Lens Opacities Classification System III(LOCS III).

SUBJECTS AND METHODS

This study was approved by the Institutional Ethics Committee of Research (Clínica Oftalmológica del Caribe, Barranquilla, Colombia) with code and number of approval CEFQX-01 and adhered to the Declaration of Helsinki's tenets.

This retrospective study of 2000 eyes was conducted in Barranquilla, Colombia from August 2017 to December 2019. A single surgeon operated all eyes and cataracts were graded using the LOCS III a standardized photographic comparison system for grading the features of the human age-related cataract

.

All consecutive cases of cataract extraction with phacoemulsification and intraocular lens (IOL) implantation were performed in a single ambulatory surgical center (Clínica Oftalmológica del Caribe, Barranquilla, Colombia). A total of 2000 eyes of adult patients who were diagnosed with a cataract were included in the study. The 1000 surgeries were performed using the Centurion Phacoemulsification System (active fluidics dynamic) and 1000 surgeries using the Infiniti Phacoemulsification System (gravity-based fluidic dynamics). All surgeries were performed by a single surgeon(Valdemarín B) and all patients were allocated randomly to each of the two systems depending on the operation room assigned. Both phacoemulsification systems were used to equal extent throughout the study period. The inclusion criteria were the following: patients diagnosed with cataract classified according to the LOCS III, corrected distance visual acuity (CDVA) inferior to 20/40 according to the Snellen Chart and individuals over 18 years of age. Patients were excluded from the study if they had a history of severe retinal disorders or detachment, clinically significant corneal endothelial dystrophy or history of corneal disease and ocular inflammatory conditions.

The study included 2000 eyes. Table 1 shows patient characteristics comparing both phacoemulsification systems.Phacoemulsification was performed in 1000 (50%) eyes with an active fluidics dynamic system and in 1000 (50%) eyes with a gravity-based fluidic system. Mean patient age was 69 years old for both systems. The 591 (59%) of patients operated with the active fluidics dynamic system and 554 (54%) of patients operated with the gravity-based fluidic system were female.Cataracts were graded with the LOCS III, 165 (16%) cataracts and 183 (18%) cataracts were graded between LOCS I and LOCS III in active fluidics dynamic system and gravity-based fluidic system, respectively. The majority of surgeries were performed on cataracts graded between LOCS IV and LOCS VI, 814 (81%) cataracts were operated using an active fluidics dynamic system and 789 (79%) cataracts were operated using a gravity-based fluidic system. White cataracts were classified as LOCS VII for analysis, 21 (2%) cataracts and 28(3%) cataracts were operated using an active fluidics dynamic system and gravity-based fluidic system, respectively.Table 2 shows a comparative analysis between phacoemulsification systems. Independent

-tests were performed to compare normally distributed variables. Mean CDE until fracture of the lens was 1.1 and 1.9 percent-seconds and total mean CDE used was 5.6 and 7.2 percent-seconds using an active fluidics dynamic system and gravity-based fluidic system, respectively(

＜0.001). Both comparisons were calculated with a 95%confidence interval (CI). A reduction of 22% of CDE used was evidenced between phacoemulsification systems using the same tip and sleeve. Additionally, a reduction in the use of aspiration fluids was evidenced between phacoemulsification systems, mean fluids used were 70 and 84 mL using an active fluidics dynamic system and gravity-based fluidic system,respectively. A reduction of 16% of fluids used was evidenced using the active fluidics system (

＜0.001).

Moreover, the rate of complications was 0.2% using the active fluidics system [1 posterior capsule rupture (PCR) and 1 zonular dialysis] and 0.9% using the gravity-based system (3 PCR, 5 zonular dialysis and 1 IOL change).

Cumulative dissipated energy (CDE) is the total ultrasound used during surgery to break down a cataract. CDE used during phacoemulsification is delivered by different ultrasound tips,that use longitudinal and torsional displacement to improve efficiencies, decreasing energy and fluids used

. Better outcomes in phacoemulsification surgeries are determined by the amount of ultrasound energy and fluids delivered to the eye

, lower ultrasound energy used during surgery results in less endothelial cell loss, less postoperative corneal edema and better immediate postoperative visual acuities

.

Both phacoemulsification systems used the same 0.9 mm 45-degree aspiration bypass system Intrepid Balanced tip and the 0.9 mm Intrepid Ultra infusion sleeve (Alcon Laboratories,2017).

CDE is displayed automatically on the Centurion (active fluidics dynamic system) and Infiniti(gravity-based system) interface and is measured in percentseconds. The CDE was calculated using the same formula for the active-fluidics system and the gravity-fluidics system(CDE=average energy amplitude times duty cycle times time in foot position 3). The amount of CDE used was measured when the lens was fractured entirely, and when all fragments had been removed. Aspiration fluids (mL/min) used were recorded from the display on each phacoemulsification system's user interface. All cataracts were graded using the LOCS III classification system. Additionally, grade VII in the LOCS III was included to classify white cataracts for statistical analysis.

Descriptive statistics were used to analyze patients' characteristics. Efficiency times were averaged, and Standard Deviation (SD). An independent

-test was performed to analyze normally distributed variables and detect statistically significant differences between phacoemulsification systems regarding CDE and aspiration fluids delivered. A scatter plot with a trend line comparing CDE used between Centurion

infiniti phacoemulsification system using the modified LOCS III classification system was performed.

values less than 0.05 were considered to be statistically significant. Statistical analysis was performed using the SPSS software (version 25;SPSS Inc., Chicago, IL, USA).

The estimated fluids used in the active-fluidic configuration were significantly lower compared to the gravity-fluidic systems (

＜0.001). Reducing aspiration fluids during surgery may diminish heat production in the wound, minimizing unwanted corneal stromal changes, wound leaks and shifts in astigmatism

. Additionally, maintaining a safe and stable anterior chamber by controlling fluctuations in IOP may reduce instability or collapse, minimizing the risk of trauma to the cornea, the iris, or the lens capsule

. Transient increase in IOP is expected during surgery, hence, improving surgical efficiencies may help reduce unwanted damage to ocular structures

. A reduction of 16% of fluids used was evidenced using the active fluidics system when compared to the gravity fluidics system. Likewise, Gonzalez-Salinas

evidenced a decrease of 9.28% in aspiration fluids used between phacoemulsification systems by a single surgeon.

其實死了才好吧！死了之后，自己便可以給她進行天葬，便可以名正言順地將刀插入她的心臟。他的心里冒出了這樣的念頭，手中的濕毛巾卻仍在給女孩擦著滾燙的臉頰。

RESULTS

作為留種的山藥按需要切段，并用多菌靈和干石灰粉按1：9的比例制成的混合粉蘸斷面，放在麻袋內或集中堆放，只要做好防凍工作（＞0℃）不凍壞，不用填埋在土中。商品山藥同樣做好防凍工作，也可以長期保存。

Figure 1 shows a scatter plot with a trend line comparing both phacoemulsification systems. The CDE used was compared between phacoemulsification systems and the cataract classification according to the modified LOCS III. Our findings evidenced that harder cataracts required higher amounts of CDE, as the nucleus is harder to emulsify. The trend line evidenced a more efficient use ultrasound and irrigation in the active fluidic system compared to the gravity-based system in all cataract classifications.

Surgery was performed according to site-specific standard operating procedures following the next steps: 1) Clear corneal incisions with MVR-Lance 20G at 40 degrees. 2) Application of intracameral Roxicain and Epinephrine 1%. 3) Injection of Trepan Blue for 30s.4) Injection of balanced salted solution and an ophthalmic viscosurgical device (OVD) sodium hyaluronate 1.4% (Bio-Hialur Plus). 5) Corneal incision of 2.75 mm at 140 degrees.6) Continuous curvilinear capsulorhexis of 5.0 to 5.5 mm with an Utrata forceps was created. 7) Hidrodissection and hidrodelamination until rotation of the lens was performed. 8)Both phacoemulsification systems used the 0.9 mm 45-degree aspiration bypass system Intrepid Balanced tip and the 0.9 mm Intrepid Ultra infusion sleeve (data on file, Alcon Laboratories,2017). 9) Phacoemulsification using vertical chop or horizontal chop was performed. 10) Aspiration of lens material and an OVD was applied to protect corneal endothelium:(hydroxypropylmethylcellulose 2%, Biocelulent). 11) Injection of the IOL provided by the institution. 12) Aspiration of the OVD and injection of intracameral antibiotic (moxifloxacin 0.5%). 13) Hydration of the incisions. 14) 10-0 nylon suture on main incision.

企業(yè)內控體系主要是對企業(yè)在經營中可能會發(fā)生的風險進行控制，這是其價值的重要體現(xiàn)。財務數據可以最直觀地反映企業(yè)經營成果，它貫穿于企業(yè)的每一個工作部門，財務管理可以對各項財務指標與財務信息進行系統(tǒng)地分析，可以發(fā)現(xiàn)企業(yè)的財務風險，這正是企業(yè)內部控制所需要的。以往財務管理只對會計事項事中和事后進行管理，一些發(fā)生或者即將發(fā)生的財務風險就不能有效地解決和規(guī)避，在企業(yè)內控體系中的財務管理強調在會計事項事前就對可能產生的風險進行防范，在風險初期就能及時遏制，大力降低企業(yè)的經營風險，提升企業(yè)內部控制水平，保障企業(yè)資產的安全。……