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OCULAR SURGERY NEWS EUROPE/ASIA-PACIFIC EDITION December 2007

Surgeon calls cisternoplasty an easy treatment for patients with dry eye

This new procedure does not replace artificial tears but allows them to last longer, which gives patients the ability to return to a more normal lifestyle.

By Juan Murube, MD, PhD
Dry eye is a common condition in ophthalmology. It is a syndrome that, with few exceptions, lasts for life. Most patients with dry eye are condemned to use artificial tears for life, and the results are frequently mediocre.

The retention time of a drop of normal saline on the ocular surface is so short that 5 minutes after its instillation the patient has evacuated it through the lacrimal pathways. The solution for retaining this fluid longer is by way of an easy operation: cisternoplasty.


Cisternoplasty. A. Two lamellae about 2 mm x 2 mm in size are taken from the most lateral part of the lid margins, one from the upper lid and the other one from the lower lid. They are detached, 0.5 mm depth, except in their anterior arista where eyelashes grow. B. The two lamellae are rotated 90° over the anterior nondetached side. C. The posterior detached sides of the lamellae are sutured to each other. The operation is finished. D and E. When the eye remains closed for several days, it is advisable to introduce a sponge piece in the space of the neo-cistern for 1 week. F. Final result. The marginal lamellae are overrepresented for easier understanding.

Images: Murube J

Cisternoplasty

The lacrimal basin is the space between the lids and the ocular surface, and the lacrimal sea is its content. The lacrimal cistern is the name that was given in 1980 to the functional space of the lateral lid canthus that contains the tear meniscus of this place, in the triadic angle formed between the lid margins of the upper and lower lid and the conjunctiva. The physiological function of the lacrimal cistern is to collect tear fluid coming from the lacrimal glands and to distribute it along the lower meniscus. The central third of the lower meniscus (the meniscal trough) is where the upper lid takes the tear at each blinking and distributes it over the anterior surface of the cornea.

The volume of a normal lacrimal sea is about 7 µL to 10 µL, of which only about 1 µL is in the lacrimal cistern. A drop of normal saline contains about 30 µL, ie, about four times more than the volume of the normal lacrimal sea. Therefore, insertion of a drop of artificial tears overfills the lacrimal basin, and the menisci of the lid margins acquire a volume and surface curvature that are different from their normal physical constant. The lack of equilibrium created between the continent and the content provokes the quick elimination of the excess liquid, and in about 5 minutes — during which the humidification of the ocular surface is improved — this artificial overcharge is eliminated and the lacrimal sea returns to its original volume. This quick elimination of the drop is delayed with cisternoplasty because the new cistern continent accepts the content of about 15 µL of a drop, and the flow of tears through the lower meniscus and puncta lacrimalia follows a rate similar to the normal one of 0.5 µL/minute to 1 µL/minute.

Cisternoplasty is the name given to the surgical technique that creates a neo-cistern in the place of the small natural cistern, increasing its capacity, making it able to retain half a drop of artificial tears, and evacuating it to the lower meniscus, precorneal tear film and puncta lacrimalia in a more normal rhythm (about 0.5 µL/minute to 1 µL/minute). Therefore, a drop of normal saline in the eye lasts for about 30 minutes.

Cisternoplasty is not a blepharorrhaphy, as it does not draw the two lids to each other but maintains their normal separation. The technique creates a new space in the lateral canthus that increases the natural lacrimal cistern.

Surgical technique

The technique consists of taking two lamellae, about 2 mm × 2 mm, from the most lateral part of the lid margins, one from the upper lid and one from the lower lid. They are detached 0.5 mm in depth, except in the anterior edge where the eyelashes grow. The two lamellae are rotated 90º over the anterior non-detached side, and their posterior detached sides are sutured to each other.

The technique is as follows:

For local anesthesia, 1 mL of an anesthetic (lidocaine 2% with adrenaline 1:100,000) is injected behind the orbital insertion of the lateral palpebral ligament.
The eyelashes of the lateral 2 mm to 2.5 mm of both lids are cut.
A lid retractor or blepharostat is placed to expose both lid margins of the lateral canthus. An anteroposterior line is painted on the upper and lower lid margin with a dermographic pencil, 2 mm distant from the lid lateral commissure. The posterior ends of both lines are joined with a V-shaped line following the posterior edge of the lid margin of both the upper and lower lids.
These delimited lamellae of both lid margins are detached 0.5 mm deep with a continuous incision of a surgical knife following the painted line. So two lamellae are detached from the lid bed, except from the anterior limit of the eyelashes edge. In the lateral commissure of the lids, the lamellae are separated from their lid substrate, but not the one from the other, their continuity being maintained with each other. (Figure 1a).
The blepharostat is removed. The resulting lamellae, one from the upper lid and one from the lower lid, are rotated forward, and the non-detached anterior limit of the lamella in the eyelashes edge serves as a hinge or axis of rotation.
The posterior limits of the lamella of the upper and lower lid are sutured with each other, with two or three stitches of a reabsorbable 6-0 to 8-0 suture. The most medial suture must be done just in the corner of the two contra-altitudinal flaps. The anterolateral wall of the new cistern is now created (Figures 1b and 1c).
The outer surface of this vertical wall is covered by the epithelium of the lid margin, but the inner surface is a crude one, and so there is a tendency to cicatrize with each other. It is possible to avoid this by maintaining the eyes normally open and blinking, but it is also possible to insert a small piece of sponge, usually taken from a Weck-cell sponge (Figures 1d and 1e), in the neo-cistern and occlude the eye for a few days. In this last case, a suture is passed from the skin of the lower lid under the middle part of the cistern to the cavity of the neo-cistern, then through the small piece of sponge, and finally it leaves the cavity of the neo-cistern through the skin of the upper lid. The two terminals of this suture are knotted and leave the cavity of the neo-cistern through the skin of the upper lid, and the piece of sponge is inserted in the cavity of the neo-cistern (Figure 1e), where it is maintained for 1 week. On its removal, the inner surface of the neo-cistern walls are already epithelialized (Figure 1f).
Results


Neo-cistern, 1 month after cisternoplasty

From the aesthetical point of view, cisternoplasty is unnoticeable because it is small (Figure 2). When looking frontally at a patient with cisternoplasty, the wall of the neo-cistern is projected in a foreshortening manner and therefore is not perceived. And when seen laterally, it is covered by the lateral eyelashes.

The content of the neo-cistern may reach about 15 µL. The outflow of an artificial tear of normal saline recovers a rate of outflow similar to the normal one because the new lacrimal basin is not overfilled, and a drop of normal saline remains in the eye for about 30 minutes. When cisternoplasty is associated with the occlusion of both lacrimal puncta, an artificial tear drop may last between 1 and 2 hours. These evaluations of times show big differences, depending on other external factors (environmental relative humidity, air drafts, etc.) and the spontaneous tear secretion that, although diminished, persists in the patient.

After the cisternoplasty, patients return to a more normal life, and with only a few drops of artificial tears, their problem is symptomatically resolved. Many patients who could not tolerate contact lenses because of dry eye can return to using them after cisternoplasty.

Conclusions

Cisternoplasty is an easy technique for patients with dry eye, especially if severity is grade 2 (symptoms with reversible signs) or grade 3 (symptoms with permanent signs), according to the Triple Classification of Dry Eye.

Cisternoplasty does not increase the production of tears. It only retains and distributes the drop of artificial tears instilled in the eyes for many minutes, and the rate of off-flow becomes similar to that of a person with a normal tear secretion. Therefore, cisternoplasty is not a substitute for artificial tears but is a complement of them because it lengthens the time of the artificial tears from a few minutes to about half an hour, diminishing the number of applications and improving results.

I advise surgeons to never perform cisternoplasty in both eyes in the same surgical session. I prefer to ask patients which eye they feel is worse, and I do the cisternoplasty only in this eye. A few weeks postop, when the patient realizes that the previously worse eye is now the better of two, I operate the other eye.


Fluid content of the lacrimal cistern, seen with fluorescein solution and ultraviolet light illumination. Left, normal case before cisternoplasty. Right, after cisternoplasty.

For more information:
Juan Murube, MD, PhD, can be reached at Clinica Murube, San Modesto 44, E-28034 Madrid, Spain; +34-917-350-760; fax: +34-917-340-956; e-mail: murubejuan@terra.es.
Reference:
Murube J, Németh J, et al. The triple classification of dry eye for practical clinical use. Eur J Ophthalmol. 2005;15(6):660-667.


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This appears to be a fairly simple procedure. It may seem like a bit of an oddity, but it makes sense and, I would think, there is a low risk of complication.

As in so many things, there is beauty in simplicity.