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Ivanov Andrey Nikolayevich, Dr. habil. in Medicine, senior researcher, Department of Traumatology and Reconstructive Eye Surgery, FSBO 'Helmholtz Moscow Research Institute of Eye Diseases',
E-mail: Road18@Yandex.ru Alekseeva Irina Borisovna, Dr. habil. in Medicine, senior researcher, Department of Traumatology and Reconstructive Eye Surgery, FSBO 'Helmholtz Moscow Research Institute of Eye Diseases',
Tankovsky Vladimir Eduardovich, Dr.habil. in Medicine, senior researcher, Department of retinal pathology, FSBO 'Helmholtz Moscow Research Institute of Eye Diseases',
TACTICS OF YAG-LASER VITREOLYSIS FOR20 YEARS
Abstract: The work is 5devoted to non YAG-Laser surgery, which is used for traumatic genesis hemophthalmia treatment, during 20 years practice.
YAG-Laser vitreolysis is a select operation or an independent unit. YAG-laser destruction on vitreous reduces the time of treatment of traumatic hemophthalmia. Keywords: YAG-laser vitreolysis, traumatic hemophthalmia.
Introduction. The vitreous body is a highly differen- traumatic changes in the vitreous body, are diverse and
tiated connective tissue, the main macromolecular components of which are water, collagen, hyaluronic acid, which ensure the metabolism of the vitreous body itself and the intraocular structures in contact with it [1, 7]. Changes in the vitreous body with violation of its transparency occur with mechanical eye injuries, uveal processes and hemorrhages in the vitreous body, when fibrinous exudation is observed with the organization of inflammatory exudate and blood. This contributes to the development ofproliferative vitreoretinopathy followed by detachment of retina and ciliary body, and by development of phthisis bulbi [2, 3].
Eliminating hemophthalmia is one of the stages of organ resuscitation. Blood exuded into the vitreous body has a toxic effect on the eye structures, causing dystrophic changes in the reticular membrane, secondary glaucoma and cataract. Organization with the formation of synechias leads to functional disorders in 47% of cases, while infection and hemoendophthalmitis in 5-7% result in anatomical death of the eye [4, 7].
Options for medical and surgical treatment, including YAG-laser destruction of inflammatory and post-
determined by pathogenetic signs [6].
The medicamentous therapy of vitreous pathology, hemophthalmia in particular, takes a long time, while its final effect remains problematic; it is aimed at reducing the vascular response, resorption of exudate, prevention of synechia development and traction of internal membranes [7, 8].
One of the leading methods for treating vitreous and retinal pathologies is closed vitrectomy, which was first offered by R. Machemer in 1971 and attracted attention with its effectiveness. At present, total or partial vitrectomy is used [3, 4], providing a rapid effect in 32-67% ofcases [4].
However, in a number of cases formation of synechias, especially in the anterior parts of the vitreous body, obstructs and complicates vitrectomy [4, 5, 6, 7].
Laser ophthalmic surgeons conducted a search for methods of affecting the vitreous body without opening the eyeball. Nd: YAG laser intervention is atraumatic [7, 8, 11], short-term and allows to dissect or prevent the formation of synechias, prevent neovascularization of the membranes and toxic damage to the inner membranes of the eyeball [7, 8, 9, 10, 11].
TACTICS OF YAG-LASER VITREOLYSIS F0R20 YEARS
To justify the validity of applying Nd: YAG laser exposure on the vitreous body as preparation for vitrectomy, we hereby present some data.
Fankhauser F. (1983) used Nd: YAG laser to form an optical channel with weakening vitreous body traction in cases of retinal detachment [10, 11]. That was the time, when the term YAG laser vitreolysis was introduced.
A number of authors believed that ND: YAG laser surgery of the vitreous body cannot be an independent unit, but only a fragment of surgical vitrectomy [2, 11]. But, at the same time they pointed out that in order to reduce the traction of the vitreous body it is better to use Nd: YAG laser in the middle or posterior part of the vitreous body, the so-called 'rear vitreolysis' [10], with an efficiency of 30-65%.
In 1991, the works of Stepanov A. V., Ivanova A. N., Khoroshilova-Maslova I.P. proved that Nd: YAG laser exposure of the vitreous body is accompanied by dilution of the vitreous body structure, appearance of enzymes in the vitreous body and by increase ofhydro circulation in the vitreous body [8].
Thus, the available data suggested prospectivity of carrying out Nd: YAG laser vitreolysis or Nd: YAG laser destruction of pathological vitreous body formations with increased fibrinolysis for the treatment of vitreous body pathology caused by hemophthalmia.
We have for the first time recommended and obtained RF patents for the invention in the sphere of YAG-laser treatment methods for vitreous body pathologies with endophthalmitis and hemophthalmia (RF patents for invention No. 2136251 as of 05.11.1996, No. 2180204 as of22.02.2000).
The materials presented are reflected in the works for Candidates of medical sciences Ivanova A. N. (1987), Bolkvadze E. R. (2004), Degtyareva E. M. (2012) and holders of Habilitation degree in Medicine Stepano-va A. V. (1990), Ivanova A. N. (2003).
The purpose of research was to present the results of non-invasive YAG laser treatment of hemophthalmia (Nd: YAG laser vitreolysis), which can prevent development as well as destroy vitreous body synechias and cause lysis of hemophthalmia.
Materials and methods. A 'Visulas-YAG II' laser device by 'Karl Zeiss' (Germany) company was used for the Nd: YAG laser action. The pulse energy was 0.8-9.2 mJ, the number of pulses was from 2 to 150, depending
on the density of the destructive process and the distance from the lens and the retina; number of sessions was 3-12. The criterion for the end of a session was the condition of the vitreous body - the saturation of the destroyed elements of blood, exudate and their ratio to the eye membranes as well as the maximum total energy of the Nd: YAG laser exposure up to 700 mJ, which was calculated in experimental studies [9].
We observed 251 patients (251 eyes) with hemophthalmia (212 men (84.5%) and 39 women (15.5%)).
The time of the first Nd: YAG laser intervention was between the first and 126th day (mean time of 17.4 days) after appearance of hemophthalmia. The energy of the Nd: YAG laser exposure was 0.8-9.2 mJ, with an average of 6.2 mJ, the number of pulses was up to 150, the number of sessions was up to 12.
After the clinical examination and localization of hemophthalmia using ultrasonic methods of research (volume, acoustic density of opacities in the vitreous body), the patients, on the background of maximal my-driasis and under local anesthesia, had a Nd: YAG laser exposure of the vitreous body performed in a mode that causes motion (circulation) inside the vitreous body and destruction of blood conglomerates, thereby enhancing the lysis of blood. If necessary, the session is repeated until the density of the hemophthalmia decreases, while the energy of the Nd: YAG laser exposure is increased from sparing (without causing any damage to vitreous body fibrils) up to obliterating for the destructive formations. In between sessions, instillations or injections of corticosteroids are prescribed, and IOP control is also performed.
Results and discussion. Nd: YAG laser irradiation on hemophthalmia led to destruction of the vitreous body synechias of various density, destruction and lysis ofblood conglomerates. Density reduction observed, according to data obtained with ultrasound, was more than 80% in 184 cases (73.3%). However, the recurrence of hemorrhage was noted in 8 cases (16%). The presence of residual finely dispersed suspension is considered normal in patients who underwent late Nd: YAG laser destruction of organized synechias and conglomerates of the vitreous body.
Such a considerable difference in terms of treatment after formation of hemophthalmia is explained by terms of seeking medical aid by patients as well as by the fact
that the outcomes of the organization are also adequately fragmented and then subjected to active lysis after Nd: YAG laser action.
Among patients who underwent Nd: YAG laser treatment without conservative hemolysis reinforcing treatment, lysis of hemophthalmia was completed on days 12-45 (average term made up 26.6 days), and in the group where this treatment was applied on days 9-33 (17.2 days). It also should be noted, that the therapeutic effect of blood hemolysis in the vitreous body is shown at half of the drug dose recommended for standard applications.
In 23 cases (9.2%) there was observed a rise in IOP up to 28-34 mm Hg, of which 17 cases required Intensive antihypertensive therapy. Nd: YAG laser treatment of hemophthalmia was continued after IOP compensation, but with a decrease in energy parameters.
Laser power was also reduced in cases of recurrent hemorrhage, while the number of laser sessions was increased.
Gentle mode was also used in cases, when there were marked concomitant complications in the eye structures.
The hemolytic effect of Nd: YAG laser exposure was also observed in the absence of visible destructive action, in fact, at irradiation without any pulsed discharges.
Upon completion of laser action, 70% of patients had vitrectomy performed. We applied the 25G three-port
technique and the aspiration mode against the background of the liquefaction of the vitreous body in 83% of cases.
The control electrophysiological screening after Nd: YAG laser exposure of the vitreous body showed a 35% less reduction in retinal parameters, than after vitrectomy with preliminary laser exposure.
In the control group, vitrectomy was performed on 50 patients (50 eyes) without any laser exposure of vitreous body.
The 20-25G three-port technique was used. A 5700 silicone oil was administered at the end of the surgery. The recurrence of hemorrhage was observed in 8 cases (16%).
Conclusions. 1. Nd: YAG laser exposure of the vitreous body is effective in case of hemophthalmia and causes its destruction, followed by lysis and liquefaction of the vitreous body.
2. Nd: YAG laser exposure of the vitreous can be either an independent surgical treatment or an additional one for the surgical or conservative treatment of hemophthalmia.
3. Vitrectomy is considerably easier performed after Nd: YAG laser destruction of hemophthalmia.
4. Nd: YAG laser exposure reduces the amount of medications for the treatment of hemophthalmia, as well as the period required for its treatment.
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