Evaluation of efficacy of new lens nucleus fragmenting forceps in cataract surgery / Avaliação da eficácia de uma nova pinça fragmentadora de núcleo do cristalino para cirurgia de catarata

ABSTRACT Objective: To evaluate the efficacy of low-cost nucleus fragmenting forceps designed to reduce the use of ultrasound during phacoemulsification. Methods: A total of 60 pig eyes enucleated 10 hours before were placed in the microwave oven, at maximum power for 10 seconds, to form cataracts with hardness comparable to a grade IV nucleus in the Lens Opacities Classification System III. Cataract extraction was performed using the Centurion® phacoemulsifier (Alcon Laboratories, Geneve, Switzerland) and Leica M620 microscope. All eyes were submitted to the pre-chop technique dividing the nucleus into four parts. After the pre-chop, the quadrants in 30 eyes were phacoemulsified with the torsional mode and were fragmented in the remaining 30 eyes after the pre-chop was with the fragmentation forceps before torsional mode phacoemulsification. The device was calibrated for all eyes by applying the following parameters: 40% linear torsional phacoemulsification; intraocular pressure of 65 mmHg; the linear vacuum of 600 mmHg; aspiration flow of 40 ccs/minute. After each procedure, the following was recorded: cumulative dissipated energy; equivalent average torsional amplitude; equivalent average ultrasonic power; estimated aspirated fluid; ultrasound total time; and total aspiration time. Statistical analysis was performed using the Kruskal-Wallis test and the IBM Statistical Package for Social Sciences. The p-value <0.05 was considered statistically significant. Results: There was a statistically significant reduction favoring the use of the nucleus fragmenting forceps in all parameters, except for the average torsional amplitude. Conclusion: The use of the nucleus fragmenting forceps contributed to improving the efficacy of torsional phacoemulsification in enucleated pig eyes.

RESUMO Objetivo: Avaliar a eficácia de uma pinça fragmentadora de núcleo, de baixo custo, desenvolvida para reduzir o uso de ultrassom durante a emulsificação do núcleo. Métodos: Sessenta olhos de porco com 10 horas de enucleação foram colocados no forno de microondas, em potência máxima por 10 segundos, para a formação de catarata com dureza comparável à de um núcleo grau IV na Lens Opacities Classification System III. A extração da catarata foi realizada com o facoemulsificador Centurion® (Alcon Laboratories, Genebra, Suíça) e microscópio Leica M620. Todos os olhos foram submetidos a técnica de pre-chop, dividindo o núcleo em quatro partes. Em 30 olhos, após o pre-chop, foi feita a facoemulsificação dos quadrantes com o modo torsional e, nos outros 30 olhos, após o pre-chop, cada quadrante foi fragmentado com a pinça antes da facoemulsificação com o modo torsional. O aparelho foi calibrado para todos os olhos com os seguintes parâmetros: faco torsional linear 40%; pressão intraocular 65 mmHg; vácuo linear 600mmHg e fluxo de aspiração 40cc/minuto. Após cada procedimento, verificaram-se energia dissipada acumulada; média da amplitude do faco torsional; média equivalente do poder ultrassônico; líquido aspirado estimado; tempo total de ultrassom e tempo total de aspiração. A análise estatística foi realizada utilizando o teste de Kruskal-Wallis com o IBM Statistical Package for Social Sciences. Valor de p<0,05 foi considerado estatisticamente significante. Resultados: Houve redução estatisticamente significante em favor do uso da pinça fragmentadora de núcleo em todos os parâmetros, menos na média de amplitude do faco torsional. Conclusão: O uso da pinça fragmentadora de núcleo contribuiu para melhorar a eficácia do faco torsional em olhos de porco enucleados.

Viscoexpression technique in manual small incision cataract surgery.

Viscoexpression method of nucleus delivery in manual small incision cataract surgery is described in this article. The practical modifications to the conventional technique in special situations are presented. Intraoperative and postoperative problems likely to be encountered and the steps to avoid them and tackle them effectively are discussed.

Nucleus management with irrigating vectis.

The main objective in modern cataract surgery is to achieve a better unaided visual acuity with rapid post-surgical recovery and minimal surgery-related complications. Early visual rehabilitation and better unaided vision can be achieved only by reducing the incision size. In manual small incision cataract surgery (MSICS), incision is between 5.5 to 7 mm. Once the nucleus is prolapsed into the anterior chamber, it can be extracted through the tunnel. Nucleus extraction with an irrigating vectis is a very simple technique, which combines mechanical and hydrostatic forces to express out the nucleus. This technique is time-tested with good results and more than 95% of nuclei in MSICS are extracted in this way offering all the merits of phacoemulsification with the added benefits of having wider applicability, better safety, shorter learning curve and lower cost.

Nuclear management in manual small incision cataract surgery by snare technique.

Manual small incision cataract surgery has evolved into a popular method of cataract surgery in India. However, in supra hard cataract, bringing out the whole nucleus through the sclerocorneal flap valve incision becomes difficult. A bigger incision required in such cataracts loses its value action, as the internal incision and corneal valve slips beyond the limbus into sclera. Struggling with the supra hard cataracts through a regular small incision. Phacofracture in the anterior chamber becomes a useful option in these cases. In the snare technique, a stainless steel wire loop when lassoed around the nucleus in the anterior chamber constricts from the equator, easily dividing the hardest of the nuclei into two halves. The wire loop constricts in a controlled way when the second cannula of snare is pulled. The divided halves can easily be brought out by serrated crocodile forceps. This nuclear management can be safely performed through a smaller sclerocorneal flap valve incision where the corneal valve action is retained within the limbus without sutures, and the endothelium or the incision is not disturbed. However, the technique requires space in the anterior chamber to maneuver the wire loop and anterior chamber depth more than 2.5 mm is recommended. Much evidence to this wonderful technique is not available in literature, as its popularity grew through live surgical workshops and small interactive conferences.

Nucleus management with Blumenthal technique: anterior chamber maintainer.

The Blumenthal;s 'Mininuc' technique enables nuclear expression through a 5-6.5-mm sclerocorneal tunnel incision using a Sheet's lens glide and anterior chamber maintainer (ACM). A 6-mm or larger capsulorrhexis, reduction in nuclear size by hydroprocedure and its manipulation manually into the anterior chamber are performed. The nucleus is expressed out of the chamber by use of hydrostatic pressure created by balanced salt solution delivered continuously through the ACM. This continuous flow from ACM to anterior chamber keeps the eye under positive pressure physiological state besides clearing the chamber of cortex, blood and pigments offering excellent visualization. The procedure, with an initial learning curve, is highly effective, applicable to all grades of cataracts, has minimum intraocular instrumentation resulting in an early rehabilitation of the patient.

Nucleus management with Fishhook.

The fishhook technique developed at the Lahan eye hospital is widely used in Nepal and other countries. Its specialty is the extraction of the nucleus with a bent 30-G needle (Fishhook) out of the capsular bag and the self-sealing tunnel. All sizes of nuclei can be extracted. The fishhook technique has a short learning curve, a low complication rate and provides excellent immediate visual outcome. It is cost-effective and has proved to be useful also for high-volume cataract surgery and thus can play an important role in the reduction of cataract blindness.

Nucleus management in manual small incision cataract surgery by phacosection.

Nucleus management is critical in manual small incision cataract surgery (MSICS), as the integrity of the tunnel, endothelium and posterior capsule needs to be respected. Several techniques of nucleus management are in vogue, depending upon the specific technique of MSICS. Nucleus can be removed in toto or bisected or trisected into smaller segments. The pressure in the eye can be maintained at the desired level with the use of an anterior chamber maintainer or kept at atmospheric levels. In MSICS, unlike phacoemulsification, there is no need to limit the size of the tunnel or restrain the size of capsulorrhexis. Large well-structured tunnels and larger capsulorrhexis provide better control on the surgical maneuvers. Safety and simplicity of MSICS has made it extremely popular. The purpose of this article is to describe nucleus management by phacosection in MSICS.

Capsulotomy and hydroprocedures for nucleus prolapse in manual small incision cataract surgery.

Manual small incision cataract surgery (MSICS) involves the manual removal of nucleus through a scleral tunnel. To achieve 100% success every time, one has to do a good capsulotomy and should master the technique to prolapse the nucleus into anterior chamber. During conversion from extracapsular cataract surgery to MSICS, one can perform a can-opener capsulotomy and prolapse the nucleus. However, it is safer and better to perform a capsulorrhexis and hydroprolapse the nucleus, as it makes the rest of the steps of MSICS comfortable. Use of trypan blue in white and brown cataracts makes the capsulorrhexis and prolapse simple and safe. Extra caution should be taken in cases with hypermature cataracts with weak zonules and subluxated cataracts.

Description of surgical technique: the Bhatti modification for small-incision cataract surgery of the Akahoshi prechop technique.

Manual chopping of the nucleus forms the backbone of nucleus reduction in manual small-incision cataract surgery (MSICS). The technique ("prechopping") described by Akahoshi has been modified so that it is safe, predictable, and easy to use in MSICS.

Phacoemulsification in hard cataracts: the chop, trip and free technique

Very hard cataracts continue to be a challenge to phacoemulsification due to the difficulty in breaking the nucleous and also in separating the broken nucleus from the adjacent epinucleus. The present technique is the presentation of a surgical maneuver which uses the Nagahara chopper and the phaco tip to divide the nucleus (including the epinucleus) as a whole and then emulsity it using little time and not very much phaco power.

Una nueva técnica para la recuperación de cristalinos y restos nucleares luxados en cavidad vítrea / Levitation: a new technique to rescue nucleus of fragments from vitreous cavity

Propósito: proponer una nueva técnica denominada "levitación" para la extracción del cristalino, núcleo o restos nucleares luxados en cavidad vítrea. Pacientes y método: se realizó en 10 pacientes vitrectomía por pars plana seguida por la utilización de una cánula de drenaje interno. Resultados: en los 10 casos tratados se extrajo el cristalino, núcleo o restos nucleares en forma completa, sin complicaciones. Conclusiones: el procedimiento resulta ser una técnica efectiva, segura, de bajo costo, reproducible y menos compleja que otras técnicas que utilizan perfluorocarbonato líquido o faco por pars plana

The effect of extracapsular cataract extraction using nucleus dislocation into anterior chamber on the corneal endothelium

When the continuous circular capsulorhexis (CCC) is being performed, the nucleus delivery using nucleus dislocation into the anterior chamber is safer and easier than using conventional "push and pull" method to maintain an intact lens capsule. This method include such procedures that after CCC, the nucleus being freed in the capsular bag by hydrodissection and hydrodelineation, then hooked with a Sinskey hook and drawn out to the anterior chamber by rotation. It may damage the corneal endothelium because of the manipulation in the anterior chamber. To investigate an effect of this method on the corneal endothelium, we performed two months time analysis of changes of the central corneal endothelial cell density (CECD) in two groups--a group with an extracapsular cataract extraction (ECCE) using nucleus dislocation into the anterior chamber and a group with a conventional ECCE. Eighteen eyes of 18 cataract patients who were operated on with ECCE using nucleus dislocation into the anterior chamber method, and ten eyes of 10 cataract patients who were operated on with a conventional ECCE method were included. The CECD was measured by specular microscopy, preoperatively, postoperatively at 1 month and 2 months. The average endothelial cell loss at postoperative 1 month was 7.20 +/- 2.98% in the experimental group and 7.88 +/- 2.93% in the control group, and at postoperative 2 months was 9.05 +/- 2.96% in the experimental group and 9.34 +/- 2.95% in the control group. The change in CECD between two groups was not statistically significant.

Nova técnica de remoção do núcleo em extração extracapsular manual planejada para implante de lente intraocular / A new technique for removing the nucleous in extracapsular extraction with intraocular lents implantation

O autor descreve a técnica que idealizou para remoção do núcleo cristaliniano em extração extracapsular manual planejada da catarata com implante de lente intraocular através de instrumentos também criados por ele e suas vantagens.