one serious intraoperative complication of cataract surgery occurs if the posterior capsule is damaged during phacoemulsification of the lens and the nucleus drops into the vitreous cavity . in such cases ,
a vitreous cutter or fragmatome must be used to extirpate the fragments of nucleus that have dropped into the vitreous cavity [ 1 , 2 ] .
the popularization of microincision vitreous surgery ( mivs ) has led to the use of 25- , 23- , and even 27-gauge systems for vitreous surgery that would formerly have been performed with a 20-gauge system .
this means that even when the nucleus drops as a complication of cataract surgery , the dropped lens is also often extirpated by mivs [ 4 , 5 ] .
however , with the decrease in vitreous cutter diameter , the suction aperture in the vitreous cutters used in mivs has also decreased , making it difficult to deal with hard fragments of nucleus that have dropped into the vitreous cavity .
in addition , when a vitreous cutter is used at high speed , the cutter aperture opens and the time for which suction is engaged ( the duty cycle ) shortens , reducing suction flow volume .
the twin duty cycle ( tdc ) vitreous cutter developed by the dutch ophthalmic research center ( dorc , zuidland , the netherlands ) also has an aperture in the inner shaft cutting blade that opens for suction and extirpation , a design that prevents a drop in suction efficiency even when the cutter speed is increased . in this study , we describe the use of a 27-gauge tdc cutter , which maintains suction power even when the vitreous cutter is driven at high speed , to deal with dropped nucleus as a complication of cataract surgery .
to treat 3 cases of dropped nucleus due to posterior capsule damage during cataract surgery ( emery - little grade 3 in 2 cases , grade 2 in 1 case ) , we used a 27-gauge tdc vitreous cutter to remove the nucleus .
a 78-year - old woman underwent simultaneous vitreous and cataract surgery for proliferative diabetic retinopathy and cataract .
part of the remaining nucleus was seen to have dropped into the vitreous cavity ( fig .
as the original intention was to perform vitreous surgery with a 27-gauge system , an attempt was made to remove the nucleus using a 27-gauge tdc vitreous cutter .
a chandelier fiber with a xenon light source ( xenon brightstar illumination system ; dorc ) was used for intraocular illumination .
a 27-gauge tdc vitreous cutter was inserted via a 27-gauge cannula , and the vitreous body behind the lens and the anterior portion of the vitreous membrane were extirpated from the vitreous body side .
the nucleus that remained within the capsule was then extirpated from the vitreous body side with the 27-gauge tdc cutter .
the vitreous cutter settings were : cut rate , 6,000 cuts per min ( cpm ) ; suction , 600 mm hg , and perfusion pressure , 30 mm hg .
the 27-gauge vitreous cutter was pressed against the remaining fragments of nucleus while suction was applied from the vitreous body side , cutting into and extirpating the nucleus without repelling it ( fig .
1b ) . as portions were extirpated and size decreased , the nucleus dropped onto the retina .
after the vitreous body had been removed with the vitreous cutter using the same settings , the nucleus that had dropped onto the retina was also removed .
the fragments of nucleus that had dropped onto the retina were picked up from the retinal surface by suction with the vitreous cutter ( fig .
extirpation of the nucleus fragments was attempted with the following cutter settings : cut rate , 6,000 cpm ; suction , 600 mm hg , and perfusion pressure , 30 mm hg .
nucleus fragments that had been picked up by the suction power of the 27-gauge tdc vitreous cutter were retained because suction power was maintained even while the inner shaft cutting blade was being driven ( fig .
pieces of dropped nucleus were also successfully extirpated with the vitreous cutter while they were skewered with the 27-gauge light pipe .
all dropped lens fragments were extirpated successfully with the 27-gauge tdc vitreous cutter alone , with no intraoperative complications . at the end of the operation ,
the trocar cannula was removed without any leakage from the scleral incision , and no suturing was required .
a 78-year - old woman underwent simultaneous vitreous and cataract surgery for proliferative diabetic retinopathy and cataract .
part of the remaining nucleus was seen to have dropped into the vitreous cavity ( fig .
as the original intention was to perform vitreous surgery with a 27-gauge system , an attempt was made to remove the nucleus using a 27-gauge tdc vitreous cutter .
a chandelier fiber with a xenon light source ( xenon brightstar illumination system ; dorc ) was used for intraocular illumination .
a 27-gauge tdc vitreous cutter was inserted via a 27-gauge cannula , and the vitreous body behind the lens and the anterior portion of the vitreous membrane were extirpated from the vitreous body side . the nucleus that remained within the capsule was then extirpated from the vitreous body side with the 27-gauge tdc cutter .
the vitreous cutter settings were : cut rate , 6,000 cuts per min ( cpm ) ; suction , 600 mm hg , and perfusion pressure , 30 mm hg .
the 27-gauge vitreous cutter was pressed against the remaining fragments of nucleus while suction was applied from the vitreous body side , cutting into and extirpating the nucleus without repelling it ( fig .
1b ) . as portions were extirpated and size decreased , the nucleus dropped onto the retina .
after the vitreous body had been removed with the vitreous cutter using the same settings , the nucleus that had dropped onto the retina was also removed .
the fragments of nucleus that had dropped onto the retina were picked up from the retinal surface by suction with the vitreous cutter ( fig .
extirpation of the nucleus fragments was attempted with the following cutter settings : cut rate , 6,000 cpm ; suction , 600 mm hg , and perfusion pressure , 30 mm hg .
nucleus fragments that had been picked up by the suction power of the 27-gauge tdc vitreous cutter were retained because suction power was maintained even while the inner shaft cutting blade was being driven ( fig .
pieces of dropped nucleus were also successfully extirpated with the vitreous cutter while they were skewered with the 27-gauge light pipe .
all dropped lens fragments were extirpated successfully with the 27-gauge tdc vitreous cutter alone , with no intraoperative complications . at the end of the operation ,
the trocar cannula was removed without any leakage from the scleral incision , and no suturing was required .
to treat 3 cases of dropped nucleus due to posterior capsule damage during cataract surgery ( emery - little grade 3 in 2 cases , grade 2 in 1 case ) , we used a 27-gauge tdc vitreous cutter to remove the nucleus . in all 3 cases , the nucleus that had dropped into the vitreous cavity
was successfully dealt with using the 27-gauge tdc vitreous cutter alone , with no intraoperative complications .
no patient required suturing because of postoperative leakage of intraocular fluid from the scleral incision , nor did any patient develop ocular hypotension or other postoperative complications .
dropped nucleus as a result of posterior capsule damage represents a serious complication that may occur during cataract surgery . in the event that the nucleus drops into the vitreous cavity ,
it is important to deal with the dropped lens without causing further intra- or postoperative complications .
however , problems include the fact that the cutter aperture is too small to easily deal with the dropped hard nucleus , fragmatomes adapted to mivs can not yet be used , and intraocular fluid leaks from the extended incision when the trocar pierces the sclera during port creation , causing a drop in intraocular pressure and making it difficult to insert the trocar .
to avoid these problems , we have previously reported a transconjunctival vitreous surgery technique during anterior chamber irrigation , a vitreous cutter , and a light pipe through the cornea incision , with perfluorocarbon liquid to float the dropped nucleus to the surface of the iris , and using an ultrasound handpiece to emulsify and suction the fragments of nucleus while the anterior chamber is still perfused .
this technique does not require creation of a scleral incision , and so prevents changes in intraocular pressure during scleral port creation , as well as retinal detachment , which contributes to postoperative incarceration of the vitreous body in the scleral incision .
as this method entails the insertion of surgical instruments via a corneal incision , however , fundus visibility may decline during surgery as a result of changes in the shape of the cornea .
in particular , the 27-gauge vitreous surgery system entails little risk of incarceration of the vitreous body in the incision , and as there is almost no leakage from the incision at the conclusion of the procedure , this system is also believed to decrease the risk of complications associated with port creation .
the rate of postoperative intraocular fluid leakage from the incision is also extremely low and suturing is seldom required , alleviating the postoperative sensation of a foreign body in the eye felt by patients .
taking reduced fundus visibility into consideration , if dropped nucleus could be extirpated with a 27-gauge vitreous cutter , 27-gauge trans pars plana vitreous surgery would be safer than transcorneal vitreous surgery for dealing with a dropped lens .
normally , a finer diameter of the vitreous cutter corresponds to a smaller suction aperture and lower suction power . as the number of revolutions per second increases , the suction aperture is also closed for longer and the duty cycle decreases
this means that the suction flow volume of a vitreous cutter declines when extirpation is being performed at a high speed .
vitreous cutters use suction power to draw the vitreous body through the cutter aperture into the inner shaft of the cutter , and the inner shaft blade moves forward against the drawn - in vitreous body and extirpates it . in this process
, the cutter aperture is closed by the guillotine blade of the inner shaft , causing a drop in suction power . to extirpate a nucleus with a vitreous cutter
requires that a portion of the lens be drawn by suction power through the cutter aperture into the inner shaft , where it is finely shredded by the guillotine blade of the inner shaft .
normally , driving the guillotine blade at a high speed lengthens the time for which the guillotine blade of the inner shaft closes the cutter aperture , causing a drop in suction power . to deal with a moderately hard or harder
nucleus requires both that suction power be maintained and that the nucleus be finely shredded , but as the suction power of conventional vitreous cutters drops when they are driven at a high speed , the nucleus is repelled from the suction aperture , and extirpation has therefore previously been carried out by running the vitreous cutter at a lower speed .
attempts to improve the shape of vitreous cutters to maintain and improve suction power have been reported .
the tdc vitreous cutter reported here is designed with an aperture in the inner shaft cutting blade , which means that even when the cutting blade is driven forward and backward , the aperture in the outer shaft is not closed . with conventional cutters ,
extirpation only occurs when the inner shaft cutting blade moves forward like a guillotine , but opening an additional aperture in the inner shaft cutting blade enables extirpation to take place when the inner shaft is driven both forward and backward .
this means that the cutter can be driven at a higher speed with almost no drop in suction power , as well as enabling efficient extirpation of the vitreous body .
similarly , the 27-gauge tdc vitreous cutter is capable of extirpating a lens with a nucleus of around emery - little grade 3 hardness by retaining it with suction power and shredding it at a high speed .
in addition , fewer postoperative complications are expected to occur when a 27-gauge vitreous system is used , meaning that fragments of dropped nucleus can be removed more efficiently and safely than with conventional cutters . however
, a nucleus of emery - little grade 4 hardness or harder remains difficult to resect efficiently with a 27-gauge vitreous cutter and must be floated to the surface of the iris with perfluorocarbon liquid and emulsified and suctioned with an ultrasound handpiece .
further studies are required to investigate procedures for cases of dropped nucleus harder than the present case .
this study was approved by the ethics committee of the jikei university school of medicine and complied with the tenets of the declaration of helsinki .
 we report herein a method for the treatment of dropped nucleus during cataract surgery with a 27-gauge twin duty cycle ( tdc ) vitreous cutter . 
 when a tdc vitreous cutter is used , suction flow volume is maintained even when the cutter is driven at a high speed . 
 this enables an emery - little grade 3 nucleus that had been difficult to treat with a conventional 27-gauge cutter to be successfully excised using only a vitreous cutter , with no intra- or postoperative complications . 
 a dropped lens during cataract surgery of up to moderate hardness can be removed using a tdc cutter alone with a 27-gauge cutter system . 
Introduction
Materials and Methods
Patients
Surgical Technique
Results
Discussion
Statement of Ethics
Disclosure Statement