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Slide 1 |
Hydroexpression with an irrigating vectis is a simple technique of sutureless extracapsular cataract extraction (ECCE) using a combination of mechanical and hydrostatic forces to express out the nucleus.1 An irrigating vectis is needed to perform the procedure. The technique is especially suited for removal of softer cataracts, which will easily mold through smaller incisions. Harder cataracts are operated on by increasing the size of the scleral tunnel. The surgery is performed either through a superior or temporal scleral tunnel incision. With larger incisions, the amount of resultant astigmatism will be less if a temporal location is used. Consequently, the uncorrected vision improves.
Peritomy
The conjunctiva and the Tenon’s layer are dissected separately. This helps to minimize
the amount of cautery applied. If the surface is smooth, without any episcleral tissue,
then the scleral dissection becomes easier. The amount of conjunctival dissection should
be minimal (i.e., 8 mm to 10 mm).
Scleral Tunnel and Sideport Incision
A 6-mm scleral incision is placed 1.5 mm to 2 mm from the limbus superiorly or temporally.
The incision may be straight or frown shaped. The scleral tunnel is constructed by carrying
forward the scleral dissection using a bevel-up crescent blade. A sideport entry is made at
9 o’clock (75º to 90º to the right side of the tunnel) and it should be 1 mm in size.
Viscoelastic is injected into the anterior chamber through the sideport incision to make the eye firm. This facilitates entry of the keratome to create the corneal valve in one motion. The sideport entry also helps in reformation of the anterior chamber at the end of the procedure as well as providing additional access for removing subincisional cortex.
The entry into the anterior chamber is made with a sharp 3.2-mm bevel-down keratome to create a corneal valve of at least 1.5 mm, which achieves the self-sealing valve. A broader corneal valve of 2 mm is acceptable because the maneuver performed through the wound is limited and the chance of distortion of corneal dome is minimal. The internal wound is then enlarged to 6 mm or 6.5 mm using a 5.2-mm blunt-tipped bevel-down blade. The internal opening should be slightly larger than the external incision to facilitate the delivery of nucleus.
Capsulotomy
Additional viscoelastic is injected and the capsulotomy is performed. Capsulorrhexis is
preferred except in patients with advanced nuclear cataracts and patients with small pupils
with hard cataracts.
Flipping the Nucleus into Anterior Chamber
With a capsulorrhexis, a forceful hydrodissection is performed until a part of the nucleus
prolapses into the anterior chamber. Then, with the help of a Sinskey hook, lens dialer, or
the cannula, the nucleus is rotated clockwise or counterclockwise and delivered into the
anterior chamber.
After a can-opener capsulotomy, a surgeon engages the superior pole of the nucleus with a Sinskey hook and tips the pole into the iris pupillary plane. The nucleus is then rotated with the same instrument in a clockwise or counterclockwise direction until it is completely in the anterior chamber, and loosened from its attachments to the equatorial and posterior cortex.
In patients with a small pupil, a can-opener capsulotomy is preferred. The iris and anterior capsule are retracted with a Sinskey hook toward 12 o’clock, and the superior pole of the nucleus is tipped up. The nucleus is partially prolapsed through the pupil so that the iris will support the superior pole of the nucleus. Then, viscoelastic is placed between the nucleus and the iris and a surgeon manipulates the iris until the iris is behind the nucleus.
If the capsulorrhexis is too small or if the nucleus too large, then it may be necessary to make more than two relaxing incisions in the capsulorrhexis rim to prolapse one pole of the nucleus. Relaxing incisions distribute the forces present during the tip-up maneuver, minimizing the risk of tearing past zonules.
Nucleus Removal
Before nucleus removal, it is necessary to ensure that the whole nucleus lies in front of
the iris. The nucleus may be removed using an irrigating vectis. This technique uses a
combination of mechanical and hydrostatic forces to express out the nucleus.
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The irrigating vectis is available in various shapes and sizes.2 We prefer a 5-mm wide vectis, with one to three 0.3-mm forward irrigating ports with a gentle superior concavity. The vectis is attached to a 5-cc syringe containing ringer lactate when in use (Slide 1).
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After prolapsing the nucleus into the anterior chamber, viscoelastics are injected above and below the nucleus. The upper layer shields the endothelium while the lower layer pushes the posterior capsule and iris diaphragm posteriorly. This creates space for the atraumatic insertion of the vectis. A superior rectus bridle suture, which helps in fixating the globe, is crucial for the success of this step. The superior rectus suture is loosely held in a surgeon’s left hand or by the assistant. The vectis is then tested outside for the patency of the ports (Slide 2).
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After confirming patency, the vectis is situated concave side up under the nucleus. One should see the margins of the vectis through the nucleus to avoid pinching of the iris and consequent iridodialysis. It is possible to visualize the vectis border in most cataracts except in very white and black nuclei (Slide 3).
The following movements should occur in synchrony. The irrigating vectis is withdrawn slowly without irrigating until the superior pole of the nucleus is engaged in the tunnel. The superior rectus is pulled tight. With the globe fixed, the irrigating fluid is injected slowly to build up the hydrostatic pressure inside the chamber and the vectis is slowly pulled out while pressing down on the scleral lip.
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These steps are crucial in protecting the endothelium. The irrigation keeps the anterior chamber well formed, whereas the downward pressure helps to open the wound and prevent the nucleus from rubbing on the endothelium. The nucleus molds through the tunnel and comes out (Slide 4).
The irrigation must be reduced when the maximal diameter of the nucleus clears the tunnel. This step prevents the nucleus from being forced out with a consequent sudden decompression and shallowing of the anterior chamber.
Management of Hard Cataracts
By increasing the incision size to 7.0 mm, one can manage any size nucleus. Brunescent
nuclei can be removed through a smaller wound by breaking the nucleus into two pieces if
it gets locked in the wound during the removal process (fragmentation at the scleral
pocket).3
Two techniques for breaking the nucleus exist. The first technique involves lifting the heel of the vectis when the nucleus gets locked in the tunnel. This usually breaks the superior 1/3 to 1/2 of the lens nucleus. Alternatively, a surgeon can remove the vectis as the nucleus gets locked in the wound and break a part of the nucleus outside the tunnel with a Sinskey hook.
The remaining nucleus may be pushed into the anterior chamber with the longitudinal axis oriented toward the 6 o’clock to 12 o’clock position and removed using the vectis. These techniques offer a surgeon the opportunity to reduce the size of most, if not all, cataract incisions.
Irrigation and Aspiration of the Cortex
Irrigation and aspiration (I&A) of the cortex is performed using a Simcoe
cannula. If a complication occurs in the removal of subincisional cortex, then I&A
can be approached through the sideport using the same cannula. The IOL is implanted in
the bag. Injecting fluid through the sideport incision forms the anterior chamber. The
wound is checked for any leak. Normally, no sutures are required because the tunnel is
self-sealing.
Relevance of Sutureless ECCE In Modern Cataract Surgery
Cataract is the leading cause of avoidable blindness worldwide, with three quarters of blindness occurring in the developing world.4Despite the 10 to 12 million cataract operations performed globally, cataract blindness is increasing by 1 to 2 million occurrences per year.5 To effectively address this increase, significant efforts are being undertaken to increase the output of cataract surgical services in developing countries6and to make cataract surgery affordable to all people irrespective of economic status.
The transition from intracapsular cataract surgery to extracapsular surgery with IOL implantation has led to a dramatic change in postoperative visual outcome, quality of life, and increased acceptance of surgical intervention by the community.
The main objective in modern cataract surgery is to achieve a better unaided visual acuity with rapid postsurgical recovery and minimal surgery-related complications. Early visual rehabilitation and better unaided vision can be achieved by reducing the incision size. The size of the incision depends on mode of nucleus delivery and type of IOL (rigid or foldable).
In standard ECCE, the incision must be 10 mm to 12 mm for safe delivery of the nucleus. In sutureless ECCE, the incision is between 5.5 mm to 7 mm and, in instrumental phacoemulsification, the incision varies from 3 mm to 6 mm depending on the technique and implant. The use of a smaller incision — with advantages of faster rehabilitation, less astigmatism, and better postoperative vision without spectacles — led to phacoemulsification becoming the preferred technique for which resources are available.
Despite excellent facilities and skilled surgeons, people in the developing world are deprived of the visual benefits of the IOL because of inability to afford them.7 With this background, phacoemulsification may not be an affordable technique due to the cost involved in the developing countries. Alternatively, manual small-incision cataract surgery (SICS) with its relatively smaller incision has similar advantages to phacoemulsification and is affordable.
Sutureless ECCE has evolved as an effective alternative to phacoemulsification. Recent studies have shown that sutureless ECCE is cost-effective and has more benefits than conventional ECCE.8 Benefits of sutureless ECCE include:
Sutureless ECCE can be performed for most types of cataracts, in contrast to phacoemulsification in which case selection is important. The duration of surgery and phacoemulsification power varies with the nucleus density, along with the incidence of intraocular complications.
In contrast, with sutureless ECCE, the time spent on nucleus delivery does not vary from case to case. In cataracts with dense nuclei, with the incision enlarged to 7 mm, the nucleus can be delivered with an irrigating vectis. An alternative technique for extraction through a smaller wound is by using the phacosandwich technique. This is a bimanual technique in which under the cover of viscoelastics the nucleus is delivered bimanually with a vectis and Sinskey hook. Phacofracture is another technique used in manual SICS to bring out nuclei of varying grades through a smaller tunnel (4 mm to 5 mm).
The use of manual SICS to remove hypermature cataracts with liquefied cortex and hard nuclei can produce excellent results. To handle hypermature cataracts with phacoemulsification is more difficult because of the fibrosed capsule, weak zonules, and hard mobile nucleus. Traumatic cataracts after penetrating trauma, colobomas, and retinal detachment surgery are better approached by this procedure.
While capsulorrhexis is mandatory for phacoemulsification, sutureless ECCE can also be done with the can-opener technique. In a study in which the learning curve in residents training on phacoemulsification was analyzed, four patients required conversion to ECCE. In three patients the reason for "bailing out" was the absence of an intact capsulorrhexis.9 In sutureless ECCE, the conversion to standard ECCE due to an absence of capsulorrhexis is not necessary because the nucleus is delivered comfortably, even with a can-opener capsulotomy.
Incidence of intraoperative complications like posterior capsule rupture is less common in sutureless ECCE when compared to phacoemulsification. In another recent study, researchers compared the safety of ECCE, sutureless ECCE, and phacoemulsification and reported a lower intraoperative and immediate postoperative complication rate in the sutureless ECCE group when compared with the rest.10
Certain phaco-related complications such as corneal burns due to the phacoemulsification probe and iris chaffing are not encountered in sutureless ECCE. The endothelial cell counts on this subgroup of patients are no different from those who have had phacoemulsification.11 Endothelial cell loss in phaco depends on the density of the nucleus12 in contrast to sutureless ECCE in which the skill of a surgeon plays an important role.
Published evidence reports that surgically induced astigmatism after ECCE is 3.91 times higher than sutureless ECCE.9 These results show that the difference in surgically induced astigmatism between sutureless ECCE and phacoemulsification with a rigid IOL was not statistically significant. Implantation of a foldable IOL, though a standard procedure in developed countries, is available only to affluent patients in developing countries. This is because the foldable IOL costs as much as 10 times as much as a rigid IOL. The final visual acuity between these two groups is also comparable. Our unpublished data show that the final postoperative visual acuity in sutureless ECCE and phacoemulsification is similar.
Surgical time in phacoemulsification is dependent on the type of cataract. In a study performed in a rural eye camp in India, manual SICS was performed within 3.8 to 4.2 minutes.10 Being a faster procedure, manual SICS can be performed in a high volume set up.
In another study from India in which cost comparison between the two procedures was performed, the average cost for the provider was $15.82 for ECCE and $15.68 for sutureless ECCE.13 Both of these surgical procedures are economical. A separate study points out the following costs: $17 for ECCE, $18 for sutureless ECCE, and $26 for phacoemulsification.9
Although the provider costs are similar for sutureless ECCE and ECCE, costs might be lower for patients undergoing SICS considering the need for fewer postoperative medications, follow-up visits, and spectacles. When these factors are considered, the total cost for manual sutureless SICS may be more economical.
Another major advantage of sutureless ECCE is that it is not a technology-dependent procedure. The surgical skills and experience of a surgeon play a significant role in the results. The considerable expense in acquiring and maintaining a modern phacoemulsification machine is not required.
Transition to phacoemulsification is easier if one has mastered sutureless ECCE, because a surgeon is already familiar with steps such as scleral pocket incisions, capsulorrhexis, and hydroprocedures. Familiarity with these steps helps reduce the incidence of complications while learning phacoemulsification.14
Instances in which surgeons must convert from phacoemulsification to ECCE occur. Researchers reported a 3.7% conversion rate from phacoemulsification to extracapsular surgery by an experienced surgeon.15 Converting to an extracapsular method may result in a larger, unstable wound compared with a manual SICS. If one is familiar with the manual nucleus delivery technique with the self-sealing wound, then one can reduce suture-induced astigmatism and other complications.
Phacoemulsification is too expensive to be employed as the standard procedure in developing countries with a large cataract backlog. High-quality, high-volume cataract surgery has been proven in eye care centers in India to be the most effective way to manage the large backlog of cataract blindness.16
In an era in which advances are linked to expensive innovative technology, it is exciting to witness the evolution of simplified, low-cost alternatives. Sutureless ECCE offers the smaller incision size of phacoemulsification and the added advantage of not requiring expensive equipment. Sutureless ECCE offers all the merits of phacoemulsification with the added advantages of having wider applicability and better safety, with a shorter learning curve and lower cost.
