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VITREOUS AND RETINAL SURGERY

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					VITREOUS AND RETINAL SURGERY
E.R.Mlildashev, V.U.Galimova, M.M.MustatIn, S.A.Muslirnov
Îôòàëüìîõèðóðãèÿ/Ophthalmosurgery-4-1996-P.36-41




                     A new method of surgical treatment of retinal detachnment: choroidal buckle using biomaterial
                     "Alloplant"
                     ´æ ææŁØæŒŁØ              º æ Ł æŒ Ø ıŁ ªŁŁ ªº ,            E ye Plastic Surgery Centre, Ufa
                     Retinal detachment surgery is known to provide a stable contact between choroid and retina. To
                     this end, several procedures are performed: with the use of various local or circular episcleral buck-
                     les [2, 7]. Scleral buckle is widely used by ophthalmologists, though it does not always provide a
                     contact between choroid and retina because of eyeball deformation followed by a number of com-
                     plications, namely, ocular hyperten-sion, disruption of the blood flow and dystrophic changes
                     [1,3,5].
                     Far more effective, in our opinion, is choroidal buckle, for this procedure is more physiological,
                     pre-vents eyeball deformity and may bring about a contact between retina and choroid in a less
                     traumatic way. The positive effect of such surgery was proved experi-mentally when the authors
                     used autocartilage and homosclera as transplants [4]. Yet the implants used for sclera buckling
                     (solid silicone, foam gel, allogenic broad fascia, dura mater, sclera, etc.) are hardly applicable for
                     buckling a delicate formation such as choroid, the more so because they have a series of short-
                     comings - rejec-tion, lingering inflammation, immune reaction, etc. [1].
                      Yet dense and nonelastic transplants may damage the choroid, morover they do not ensure the
                     implant’s even density and adequate modelling of the mem-branes’ prominence by a dosed intro-
                     duction of the buckle into suprachoroidal space.
                     For a choroidal buckle implant use was made of allotransplant biomaterials proposed by us and
                     widely applied in practice (Specifications 42-2-537-88, approved by the Ministry of Health of the
                     USSR). Allotransplants of the Alloplant series are known to be gradually replaced by the recipient’s
                     tissue, without causing an immune reaction. Of particular interest to us was the group of alloplants
                     that are replaced by richly vascularized tissue. Such alloplants, used exten-sively for revasculariz-
                     ing choroid, were introduced in the ocular suprachorioidal space [6].
                     In creating a special alloplant (with a view of its being replaced by abundantly vascular tissue) for
                     choroidal buckling, we solved two problems at once: achieved a steady contact between choroid
                     and reti-na and improved the blood circulation of the earlier detached retina. It was also necessary
to develop the technique of buckling choroid and indications to its performance in case of retinal
detachment.
In this work we study the possibilities and analyse results of a new trauma-free method of treatment
of retinal detachment by buckling choroid with the use of Alloplant as a buckle.
Material and methods. The alloplant for choroidal buckle (Specifications 42-2-537-93,
approved by the Ministry of Health of RF) is made from facial tissue with fibroarchitechtonics
being 70% similar to normal choroid, and has a higher content of chondroitin-sulfate. The alloplant
is produced as a tape 100 mm long, 10 mm broad and 0.3 mm thick. It is gamma-sterilized, with
bacteriological, AIDS and hepatitis control. It is kept in a preservation solution at room tempera-
ture for 5 years.
The buckle technique with the said alloplant was developed first on 6 enucleated cadaveric eyes,
and then in clinical experiments with rabbits.
The experiments involved 18 rabbit eyes. Through the penetrating incision of sclera, the allo-
plant was introduced into the suprachoroidal space for scleral buckling and was laid there in folds
to form a choroidal torus. The operated on eyes were enucleated in 3, 7, 14 days and 1, 3, 6 months
after surgery, fol-lowed by histological examinations of the serial sec-tions.
Clinically, 21 patients were subjected to more detailed analysis with the study of surgical results in
dynamics during 1-3 years. 14 of them had traumatic and 7 idiopathic detachments, and 8 patients
(38%) had from one to three recurrences of retinal detachments after performed operations (the
buckling of sclera by silicone, etc.).
The patients were divided as follows.
         In terms of the spread of detachment:
                     local (1-2 quadrants of the eyeball) - 9 patients (42.8%);
                     subtotal (3 quadrants of the eyeball) - 5 patients (23.8%);
                     total (4 quadrants of the eyeball) - 7 patients (33.3%).
         In duration of detachment:
                     up to I month - 3 patients (14.2%);
                     1-12 months-7 patients (33.4%);
                     1-3 years-5 patients (23.8%);
                     3-18 years - 6 patients (28.5%).
         In visual acuity before surgery:
                     wrong light projection - 2 patients (9.5%);
                     correct light projection - 15 patients (71.4%);
                     counting of fingers at face - I patient (4.7%); 0.01-0.05 - 3 patients (14.2%).
Moreover, retinal tears in 6 patients were valvu-lar, in 3 - single perforated and in 5 - multiple per-
forated, their size ranging from 1/4 to 1/2 diameter of the optic disk. The tears were positioned
equatorially and postequatorially, primarily in the superior-outer and superior-internal quadrants.
One patient was diagnosed to have a paramacular tear, 4 - gigantic tears up to 2 diameters of the
optic disk located pre-equatorially and equatorially, primarily in the lower half of the eyeball. There
were 2 tears from the ora serrata of the 900 and 1200 length.
The above indicates that it is the most serious patients with retinal detachments, i.e. those consid-
ered incurable, that underwent surgical intervention.
                                        Operation technique. Generally, the choroidal buckle technique
                                        con-sisted of the following. Conjunctiva was incised in the projec-
                                        tion of the detached sclera. Diathermocoagulation of sclera was per-
                                        formed followed by the pene-trating incision of sclera 6-8 mm in
                                        length. The suprachoroidal space was opened. The alloplant was
                                        dipped into a physiological solution and placed in the wound area;
                                        the end of it was put over a spatula, introduced into the suprachori-
                                        oidal space and moved over the required distance. The spatula was
                                        removed and used to intoduce the alloplant tape by parts into the
                                        suprachorioidal space. The forming folds resulted in choroidal
Fig.1. Diagram of choroidal buckle by   buckle (Fig. 1).
introducing a transplant into the
suprachoroidal space.                   When the alloplant is being introduced, the surgeon begins to feel
                                         the increase in the intraocular pres-sure. To reduce it is sufficient to
                                         turn the spatula with its edge towards choroid and release the sub-
                                         retinal liquid. When this did not help we incised the choroid.
                                         The height and extent of choroidal buckle were controlled by means
                                         of a binocular ophthalmoscope. A portion of the alloplant tape or 2-
                                         4 alloplant tapes are used, considering the character of retinal
                                         detachment.
                                        The part of the alloplant sticking out of the wound was fixated by
                                        sutures and the scleral wound was stiched. Sterile air was intro-
Fig. 2. Diagram of choroidal buckle     duced into the vitreous through an additional incision in the scleral
within one quadrant.                    pars plana to create hypertension of the eye. We have worked out 4
                                        options of choroidal buck-le, which may be combined whenever
                                        necessary.
         1. Choroidal buckle within the limits of one quad-rant of the eyeball (Fig. 2).

         2. Choroidal bucle within two quadrants of the eyeball (Fig. 3). Two alloplants are intro-
            duced through one incision - to the left and to the right of the inci-sion.

         3. Circular choroidal buckle. Two scleral incisions are made at mutually antithetic sectors
            of the eyeball, and two alloplant tapes are introduced through each incision (Fig. 3).

         4. Choroidal buckle in the macular area (Fig. 4). The sclera is incised 12-15 mm from
            limbus in the inferior-medial quadrant of the eyeball.

                                        Results and discussion. Experimental histomorphological
                                        investigations have shown that in the early period (3-14 days) the
                                        alloplant, introduced into the suprachoroidal space, causes slight
                                        edema of the retina and choroid. At this time there occurs prolif-
                                        eration of fibroblasts, macrophages and pigmental melanocytes,
                                        and blood vessels (originating from choroid and episclera) begin to
                                        grow into the alloplant. Later (between the 14th and the 40th day)
                                        regeneration of the vessels continues, and connective fibrillar struc-
                                        tures begin to form. The cellular density infiltrate is diminishing,
                                        and edema of the retina and choroid fully disappears. On the 180th
Fig. 3. Diagram of choroidal buckle     day, at the place of the introduced alloplant there are friable con-
within two quadrants.                   nective formations, a richly vascular chan-nel and homogenized
                                        fragments of the alloplant, pre-serving the fold structure.
                                                          So, experiments have confirmed that the allo-plant for
                                                          choroidal buckle causes weak reaction on the part of
                                                          retina and choroid and is gradually replaced by tissue
                                                          rich in blood vessels.
                                                          Postoperatively, all the operated on patients showed a
                                                          weak or moderate inflammatory reaction without
                                                          complications. According to echography, within I
                                                          month the retina attached completely in 18 (85.7%) of
                                                          21 patients, and partially in 3 (14.2%). Within 6-12
                                                          months, retinal detachment recurred in 3 patients
                                                          (14.2%), full retinal attachment was registered in 10
                                                          (47.8%) and partial attachment in 8 (38%). The same
                                                          results were registered during I to 3 years.
Fig. 4. Diagram of choroidal buckle in the macular area
                                              Ophthalmoscopically, the picture throughout the fol-
                                              low-up was marked by obvious stability and the pres-
ence of eye membranes’ prominence in the zone of retinal defects as even elongated buckling.
Long-term, the retina in the tear area closely attached to the buck-ling and was moderately pig-
mentized. Behind the pig-mentation zones and around the retinal defects there were clear-cut chori-
oretinal atrophic foci extending to the buckling boundaries.
It is necessary to note the serious condition of the operated on patients: half of them (57.2%) had a
total and subtotal retinal detachment. Besides, 38% of patients were operated on for 1-3 recur-
rences of reti-nal detachment. Therefore, the achieved results may be considered satisfactory, the
more so because partial attachment was considered the presence of even a small detached part of
             the retina not affecting visual functions.
             Visual acuity dynamics is shown in the Table.

             Table. Dynamics of visual acuity of patients who underwent choroidal                              buckle
             (21 patients)
             Visual acuity                           Before surgery                       1-3 years alter surgery
             Wrong light projection                  2                                    2
             Correct light projection                15                                   -
             Counting of fingures at face            1                                    1
             0,01-0,05                               3                                    13
             0,06-0,09                               -                                    3
             0,1-0,4                                 -                                    3
             till 0,6                                -                                    1

             The Table shows that visual acuity increased in 18 patients (87.5%). In our opinion, such visual
             effect in seriously ill patients (52.3% of them had retinal detach-ments for 1 to 18 years) is due to
             the establishment of a contact between retina and choroid and to the alloplant’s positive effect on
             the metabolism of choroid and retina. To sum up, the described choroidal buckle proce-dure involv-
             ing an alloplant as biobuckle may be rec-ommended for wide application in the treatment of heavy
             forms of retinal detachments.

REFERENCES

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