Intraoperative posterior capsular rupture (PCR) leading to vitreous loss into the anterior chamber (AC) can occur in complicated cataract surgeries.[1,2] Vitreous, the transparent gel, has the property to enmesh and create significant entanglement with the adjacent structure with which it comes into contact.[3] The untreated vitreous will thus prevent further intraocular lens (IOL) placement and cause significant postoperative complications like macular edema, retinal traction, abnormal pupil, and glaucoma.[4] Hence, the removal of the vitreous from the AC and pupillary plane is the initial step after any intraoperative PCR. The conventional vitrectomy system is of guillotine type; which is enabled by either the pneumatically-driven or the electrically-driven cutter.[5,6] In this surgical technique section, we present the utility of hypersonic vitrectomy which uses ultrasound energy for vitreous liquefaction and removal in a complicated phacoemulsification case with retained nuclear fragments.
A 64-year-old female patient who complained of decrease in vision in both eyes for three months duration was seen in the out-patient department (OPD). On examination, she had bilateral NS 2 cataract with normal anterior segment. Her fundus and intraocular pressure (IOP) were normal. Her preoperative visual acuity was unaided 20/100 in both eyes. She underwent phacoemulsification surgery for cataract (nuclear sclerosis grade 2) in the left eye under local peribulbar anesthesia. Initial steps of capsulorhexis and hydrodissection were performed. Intraoperative PCR and nucleus drop into the vitreous occurred during phacoemulsification. The patient underwent retained lens matter removal using a hypersonic vitrectomy system under local anesthesia in the same sitting.
Surgical Technique
Hypersonic vitrectomy system
The Vitesse vitrectomy system comprised of (1) the vitrectomy hand piece, (2) the Bausch + Lomb Stellaris Elite™ Vision Enhancement System [Fig. 1a and 1b], and (3) the transscleral entry site alignment (ESA) cannula system. The hand piece [Fig. 1b] uses ultrasonic and harmonic (29.5 kHz) waves to generate mechanical cutting action for fragmenting and removing the vitreous [Video File 1]. The needle is 23-gauge (G), has an outer diameter of 0.64 mm with a closed distal end, and a side port diameter ranging from 0.18 to 0.25 mm. The needle reciprocates with stroke length of 0–60 μm.
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Figure 1: The Vitesse vitrectomy system showing (a) the Bausch + Lomb Stellaris Elite™ Vision Enhancement System and (b) the Vitesse vitrectomy hand piece needle
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Triumvirate technique with hypersonic vitrectomy
Trocar anterior chamber maintainer (TACM) was inserted at the infero-temporal quadrant 7 o ’clock hours at the limbus. Two scleral flaps about 180° apart was fashioned at 3 and 9 o’clock hours [Fig. 2a–f]. Two sclerotomies were subsequently performed below the scleral flaps for subsequent glued IOL procedure. The nuclear pieces were elevated with the modified posterior-assisted levitation (PAL) technique with the globe stabilization rod passing through the sclerotomy. The Vitesse probe was introduced through the side port, and the vitreous in the anterior chamber was removed [Fig. 3a–f]. The stoke length ranged from 30 to 40 μm and the vacuum was 160 to 250 mmHg. The retained cortex in the AC was also liquefied and aspirated simultaneously into the probe. A three-piece foldable posterior chamber IOL (AMO) was injected through the main port [Fig. 3] to act as an IOL scaffold for the nuclear fragments.[7–9] Iris retractors were then used to expose the peripheral cortex removal and visualization. Vitrectomy was continued at the pupillary plane below the iris and on the IOL [Fig. 4a–d]. Lens fragments dropped in the vitreous were removed by posterior vitrectomy with the same probe through the sclerotomy site and internal illumination using an endoilluminator [Fig. 4e, 4f]. Once the vitreous was cleared from the pupillary plane and AC, the glued IOL procedure was performed [Fig. 5a–e].[7] TACM was removed and AC was formed by air bubble. The scleral flaps were then opposed by fibrin glue [Fig. 5f].
Figure 2: (a) Posterior capsular rupture with nucleus drops in the anterior vitreous and retained lens fragments in the anterior chamber (AC). (b) Two scleral flaps 180° apart were made. (c and d) Trocar anterior chamber maintainer placed. (e) Hypersonic vitrectomy probe introduced into the AC and vitrectomy performed. (f) Sclerotomy made below the scleral flaps
Figure 3: Intraocular lens (IOL) scaffold-assisted vitrectomy performed. (a and b) After initial vitrectomy in the chamber and levitation of nucleus, IOL is placed on the iris. (c–e) Retained lens fragments emulsified on the IOL optic. (f) Iris hooks inserted for better visualization of periphery of lens
Figure 4: (a and b) Hypersonic vitrector passed through the sclerotomy ports and vitrectomy performed. (c and d) Simultaneous emulsification of lens fragments was done through the vitrector. (e and f) Posterior segment was examined for any dropped fragments and was removed by the same hypersonic vitrector under internal illumination
Figure 5: Glued IOL procedure was performed. (a–c) The three-piece posterior chamber IOL was repositioned from the iris as glued IOL by intra-scleral tucking of the haptics on either ends. (d and e) TACM was then removed. (f) Anterior chamber was formed by air, scleral flaps were opposed by fibrin glue, and the clear corneal wound was closed by 10-0 nylon
The patient was started on topical antibiotic-steroid combination q.i.d for initial two weeks postoperatively and then tapered subsequently. Postoperative day 1 showed well-centered IOL with mild corneal edema with round pupil. On day 7, the cornea cleared with stable IOL and corrected distant visual acuity (CDVA) of 20/20. The dilated fundus examination was normal with no wound leak or vitreous wick. The postoperative specular count at six months was 1800 cells/sq. mm with CDVA 20/20 [Fig. 6].
Figure 6: (a) Intraoperative image showing posterior capsular rupture with nucleus drop in the anterior vitreous and retained lens fragments in the anterior chamber and (b) the same eye postoperative one month with clear cornea and well centered IOL
Discussion
Management of vitreous loss during phacoemulsification has been widely reported and studied in the last two decades. Since the introduction of vitrectomy by Machemer et al.,[5] the vitrectomy technique has undergone tremendous modifications.[6,10–16] Various approaches like limbal, corneal, pars plicata, and pars plana have been employed appropriately for individual cases as per indications; however the basic mechanism of vitrectomy was conventionally “the pneumatic-driven” pulse.[1,2] The pneumatic system has been the gold standard in vitrectomy. Though new generation cutters maintain high flow rates with increasing speed, there are some limitations related to the mechanical cutters, such as, the turbulences created by the periodic opening and closing of the port.
Ultrasound-based aspiration and liquefaction has been routinely used for lens liquefaction.[17] Phacofragmentation is another method of lens fracturing which also utilizes ultrasound in the posterior chamber for retrieving the dropped hard nucleus.[18] Neither phacoemulsification nor phacofragmatome devices have approved label indications for vitrectomy. On the other hand, hypersonic vitrector is an ultrasound-based vitreous removal device that uses ultrasound power in range with the conventional phacoemulsification. This is also the only available ultrasonic device that offers a cannulated posterior lens removal approach for true minimally invasive procedure. The usual limitations with guillotine are often the (1) turbulence created by the periodic opening and closing of the port, (2) vitreous material may be caught between the inner needle and the port edges, (3) the outer needle port must be large enough to permit a reasonable amount of tissue to enter to achieve a cut. Rather than being cut, the vitreous is aspirated uncut, or partially cut, through the port, resulting in direct traction on the vitreous strands.[19] The initial studies by Stanga et al.[19] has shown the efficacy of hypersonic vitrector to overcome turbulence and traction in the vitreous.[20] The hypersonic vitrectomy ex vivo study compared the conventional guillotine vitrector with the hypersonic vitrector in-vitro in vitreous and water.[19] The hypersonic vitrectomy system uses low amplitude ultrasonic motion of the tip to create oscillating high speed shear action at the port that cuts the vitreous. This allows the hypersonic vitrector to reduce turbulence. The hypersonic vitrector has a single lumen design instead of two, so there is no chance of trapping vitreous strands between the port edge and the needle. The port is continuously open, allowing smaller port sizes and larger inner-lumen diameters which in turn lowers flow resistance and required vacuum levels.
An ex vivo study on porcine eyes showed similar histological features on the tissue in both guillotine and hypersonic vitrector.[20] As we know with the improvised microvitrectomy instrumentation (23G or 25G), the reduction in incision size alone may not help, as the drawback of low flow rate and sometimes greater vitreous traction with smaller gauge vitreous cutters can persist.[21] A recent first-in-human trial, where core vitrectomy, peripheral vitreous removal and posterior vitreous detachment induction were performed with hypersonic vitrectomy showing promising postoperative results.[22]
Though the technique is the first of its kind, where a hypersonic vitrector is being utilized for vitrectomy and lens removal in a PCR, the effectiveness of the vitrector in hard nucleus is unidentified. One can agree that all the steps would have been performed with existing systems; however, the additional improvements in technology has been highlighted as reduced turbulence and traction. Only a long-term, large-population, randomized trial can help in comparison of techniques on long term effects. We agree the system is expensive and may not be affordable for all centers. Nevertheless, the additional indication of the technology can always improve the skill set in future. Pneumatic vitrectomy has stood the test of time and hypersonic vitrectomy is yet to prove its value, and therefore we believe further research on more surgical outcomes of the hypersonic vitrector will throw additional light in the future.
Conclusion
Hypersonic vitrectomy utilizes ultrasound energy to liquefy vitreous and remove retained lens particles in single sitting with minimal complications. Therefore, it is an useful surgical tool in complicated cataract surgeries with intraoperative posterior capsular rupture with vitreous loss.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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