After surgical pterygium excision, its recurrence is common even up to 64% for some authors, indicating the difficulty of their treatment. In this article we review the most relevant for identification and treatment guidelines to get resolution.
WHAT WE MEAN BY RECURRENT PTERYGIUM
Whenever after treatment of a primary or recurrent pterygium, either with drugs or surgery, there is a reactivation of the inflammatory process in the treated area, we talk about recurrence.
This definition is important because it is not necessary to wait for the recurrent pterygium invades the cornea, simply visualize changes in the conjunctiva like vascular congestion and thickening, will be sufficient to warn us of the beginning of a new recurrence. Another issue is the interval from the first surgery and recurrence. In most publications (1-4) means that 90% of recurrences occur between the first and third month, although cases have been reported in more than 1 year after the initial treatment (4).
The problem we have at the time to decide the therapeutic line begin with the fact that there is no clear consensus about what we have to do and that would explain the variability in the data of recurrence found in literature, from 3% in the series of Salomon (5) to 63% in Essex series (6).
WHAT FACTORS PREDISPOSE TO RECURRENCE
Generally there are two groups of factors which are related to recurrence, someone due to surgery and some other due to the patient and environmental situations. In the first case, we usually have incomplete primary surgery:
- Not removed all affected tenon
- Fibrotic tissue debris left in the cornea and limbus
- Sclero-corneal surface rough, with irregularities
- Conjunctival suture tension edges
- Sclero-corneal limbus exposed, not covered with the conjunctiva or implants that we had used (amniotic membrane or conjunctiva) .
- Conjunctival edge dehiscence
- Poorly controlled inflammatory reaction
- Regarding personal and environmental factors are:
- Male patients and younger than 40 years
- Patients of Asian, African American and Hispanic.
- Presence of VEGF-460 gene (associated with vascular proliferation and pterygium)
- Exposure to a dry and dusty
- Presence of a dry eye syndrome
PATHOPHYSIOLOGY OF RECURRENT
The mechanism that explains the recurrence is the reactivation of the inflammatory process present in the primary form. Surgical trauma acts as an inflammatory response enhancer.
If after surgery limbus stem cells remain activated and fibroblastic tissue is active as well the consequence is an increase of proliferative cytokines and growth factors (VEGF), which induce the fibrovascular proliferation, while increasing the synthesis of metalloproteinases that destroy the membrane Bowman and stromal collagen, facilitating progress of pterygium (7.8).
WHAT ARE THE FUTURES OF RECURRENT PTERYGIUM
In most cases there are signs of more aggressiveness, more violent inflammatory reaction with fibroblastic proliferation, thickening and irregularity of the affected tissues. Sometimes the process can produce cicatricial symblepharon and limitations in ocular motility. Tan DT performed a morphological classification in 1997 that still continues in use and helps us identify the type of recurrence (9).
In cases in which conjunctival grafting or amniotic membrane implants was performed tissue retraction is frequently observed.
One of the ways we have to identify the activity of a recurrent pterygium is ultraviolet fluorescence photography, showing the points of maximum activity and its progression to the cornea (10).
HOW TO TREAT RECURRENT PTERYGIUM.
There is no full consensus on how to address the treatment of recurrent pterygium, so we want to give some guidelines that are very personal, the result of what we have found published in the literature and also the fruit of long experience in dealing with these cases.
Once we are in front of a recurrence, even after successful surgery and adequate postoperative treatment with anti-inflammatory and lubricating the ocular surface, the first step is the preparation of these patients for further surgery.
In most cases where there are signs of inflammatory reactivation in early inflammatory postoperatively, we recommend more intensive topical anti-inflammatory treatment, with corticosteroids and if necessary add immunomodulators such as Cyclosporin A. Mitomycin C in drops has not shown significant improvement and is accompanied by many side effects, particularly irritation and toxic keratitis (11), in the same manner, 5-fluorouracil showed no fully satisfactory results (12), thereby not recommend its use.
Currently being tested treatment with topical anti-VEGF, such as Bevacizumab, since studies on the pathophysiology of recurrences show the increase in VEGF (13,14). The results obtained are very encouraging, concluding that in most cases obtained a significant reduction of the recurrence, even in some cases surgery was not required and in cases where surgery itself was required for complete cure, was always less surgical trauma and the risk of subsequent relapse also was reduced (15,16). We have no personal experience with the use of topical Bevacizumab and therefore we cannot yet pronounce on its effectiveness.
Perhaps one of the treatments that we are giving better results is the subconjuctival infiltration with Mitomycin C. The injection of Mitomycin C, 0,015%, 1 month prior to surgery, is able to reduce the recovery time of the patient, the inflammatory response and the postoperative recurrence rate, as proposed Mandour (17) and no side effects are seen, contrary when administered in a topical form.
At this point we started using subconjunctival Bevacizumav, three weeks before surgery, as proposed by Bahar (18) and Razeghinejad (19) but there is still time to verify their potential effectiveness.
After this preparation of the patient we are able to raise surgery, following recommendations that we present in the next section.
GUIDELINES TO AVOID A NEW SURGICAL RECURRENCE
The key to avoiding a new surgical recurrence can be grouped into four points:
- Wide excision of the affected area.
- Carefully resection of the corneal area (head pterygium), from the limbus toward the center of the cornea.
- Complete cleaning of corneoscleral limbus
- Smoothening of the treated surface
- Application of Mitomycin C to prevent fibroblast proliferation (intraoperative injection of Bevacizumab has not shown satisfactory results in the incidence of recurrence (19).
- Conjunctival autograft or amniotic membrane implant to cover the entire denuded area without tension areas and caring for it is well bet on the limbus.
- Bioadhesive graft fixation to avoid which usually induce inflammatory reaction sutures.
The success of surgery involves proper postoperative treatment with anti-inflammatory and lubricants. During the immediate postoperative period remains a disruption of the tear film because the irregularity of tissues, are raised and induce an impairment of BUT that is usually less than 10 seconds, so it is essential to prevent drying areas (Dellen), which could induce greater inflammation.
Lubricants are essential to prevent rubbing mechanical trauma to the eyelid over the treated area, especially if we have used bioadhesives to fixed the implant (20,21).
Proper implementation of these recommendations may explain differences in recurrence statistics in relevant publications, which as noted ranging from 3% in the case of Salomon (5), to 64% in the case of Essex (6). In what seems to be more consensus is that the conjunctival autograft technique is working best, even over amniotic membrane implants (22,23), the problem is that there have not always enough contralateral conjunctiva, especially in complicated cases, bilateral advanced pterygium, symblepharon,or limbal insufficiency , in these cases we are forced to use amniotic membrane.
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