RU2199295C2 - Surgical method for treating congenital glaucoma in children by means of combined ultrasonic trabeculectomy - Google Patents

Abstract

FIELD: medicine. SUBSTANCE: method involves performing penetrating sinusotrabeculectomy. Superficial scleral flap is cut out and separated by means of ultrasonic scalpel and ultrasonic round knife with gradually growing amplitude enough for obtaining required cutting and coagulating result. After the flap having been separated, the internal surface is smoothed with an additional ultrasonic treatment. Deep sclera layer and corneoscleral trabecular strip are excised with blade. When suturing conjunctiva, additional interrupted sutures are put in on the conjunctiva and Tenon's capsule. EFFECT: enhanced effectiveness of treatment. 4 dwg

Description

 The invention relates to pediatric ophthalmology and is intended for the surgical treatment of congenital glaucoma in children.

 Congenital glaucoma (VG) is a group of severe disabling diseases of childhood, which are based on the presence of structural anomalies of the anterior chamber angle (CAP) of a congenital, and usually hereditary, nature. The presence of an obstacle to the outflow of intraocular fluid (IHC) leads to an increase in intraocular pressure (IOP) and, with untimely initiation of treatment, to irreversible glaucomatous changes in the neuroreceptor apparatus of the eye.

 Given the organic nature of the obstruction to the outflow of HPV, surgical treatment of congenital glaucoma; drug treatment has only an auxiliary value. The purpose of surgery for congenital glaucoma is to remove the obstacle and / or create new ways for the outflow of HPV. Currently, most ophthalmologists in the world consider trabeculectomy (TE) and its modifications to be the most effective, safe and universal method of treating all forms of childhood glaucoma (Khvatova A.V., Arestova N.N. Twenty years of experience in treating congenital glaucoma in children. // Actual issues of pediatric ophthalmology .: Mater, scientific - practical conference of the Helmholtz Scientific Research Institute of GB.- M., 1997. - P. 61-64; Fulcher T. et al. Long-term follow up of primary trabeculectomy for infantile glaucoma . // Br-J-Ophthalmol. 1996 Jun; 80 (6): 499-502; Khaw PT. What is the best primary surgical treatment for the infantile glaucomas? // Br-J-Ophthalmol. 1996 Jun; 80 (6 ): 495-6).

 However, despite the fact that this method provides a direct hypotensive effect in almost 100% of primary operations, only about half of them remain effective for more than 6 months - 2 years. The cause of the instability of the hypotensive effect of TE operations is considered to be cicatricial obliteration of the created pathways of the outflow of intraocular fluid (Sidorov E.G. et al. // Congenital glaucoma and its treatment. - M .: Medicine, 1991; Molteno AC et al. Surgical technique for advanced juvenile glaucoma . // Arch-Ophthalmol. 1984 Jan; 102 (1): 51-7).

 Until now, the main method of preventing excessive scarring after TE operations on the eyes of children with congenital glaucoma is the use of medication antiproliferative and cytostatic agents - 5-fluorouracil (5-FU) and mitomycin C (MMS) (Polutornov A.L. et al. Anticarcinotherapy 5-fluorouracil after antiglaucomatous operations at a young age // Proc. Report 3 All-Russian conference on the Act of the Children's Ophthalmol. - M., 1989. - P. 344-345; Susanna R. Jr. et al Mitomycin as adjunct chemotherapy with trabeculectomy in congenital and developmental glaucoma. // J Glaucoma 1995: 4: 151-7). However, the use of these funds is associated with an increased risk of complications such as: a discrepancy between the edges of the conjunctival incision and external filtration of the upper respiratory tract, severe hypotension, secondary hypotonic dystrophic changes, cystic degeneration of the filtering pad; Complicated cataracts, retinal detachment, endophthalmitis are also possible. The data obtained by different authors in the long term indicate an insufficiently high increase in the effectiveness of trabeculectomy when using 5-FU and MMS, which, with the possibility of developing the above complications, casts doubt on the feasibility of using 5-FU and MMS in children. The search for new ways to prevent excessive scarring in order to increase the effectiveness of surgical treatment of children with congenital glaucoma remains one of the main directions of modern research.

 One of the promising new ways to prevent excessive scarring in glaucoma surgery is the use of low-frequency ultrasound. The use of microsurgical instruments, oscillating with an ultrasonic frequency of 44 kHz and an amplitude of 10-15 μm, provides ease and bloodlessness of incisions (moreover, coagulating and hemostatic effects are achieved without thermal burns of tissues), as well as a direct antiproliferative effect, which in combination significantly reduces the invasiveness of the operation, warns excessive scarring in the area of antiglaucomatous intervention, creating conditions for long-term compensation of IOP in the postoperative period (M. B. Kodzov et al. The use of ultrasound instruments for some ophthalmic surgical interventions. // Abstracts of the III All-Russian Congress of Ophthalmologists. - M., 1975. - P.272-274).

 One of the known ultrasonic methods for the surgical treatment of open-angle (OAG) and angle-closure (ZUG) glaucoma in adults is Ultrasonic sinusotrabeculectomy (synonym: Ultrasonic trabeculectomy, UTE) (Suprun A.V. et al. Use of low-frequency ultrasound in glaucoma microsurgery. // Methodic. Recommended by the Moscow Research Institute of the Helmholtz State Library. - M., 1986. - P.7).

 This method is an ultrasound modification of standard microsurgical trabeculectomy according to Cairns (Cairns JE Trabeculectomy: preliminary report of a new method. // Am. J. Ophth. -1968. - vol. 66. - 4. -P.673-679) using ultrasonic ophthalmic surgical apparatus UZH-201. The UTE method includes: 1) isolation and separation of the scleral flap with an ultrasound knife UZN-202 (1 position of the amplitude adjustment knob = 10-15 microns); 2) excision with a USZ-202 ultrasound microscalpel of a block of deep scleral layers 1x4 mm in the projection of the drainage zone (2 position of the amplitude adjustment knob = 15-20 μm). Despite the existence of developed recommendations on the method and regimes of ultrasound exposure, UTE surgery has not been widely used in adult glaucoma surgery. This is due to significant hyperfiltration of the HPV with severe hypotension observed after UTE, which in adult patients is associated with an increased risk of complications - exudative detachments of the choroid and retina. In comparison, in childhood glaucoma surgery, such complications are extremely rare. However, the use of UTE for congenital glaucoma in children in this form is not possible, because: 1) the UTE method does not take into account the extreme variability of the physical properties of sclera in children with congenital glaucoma, the need for individual selection of the optimal amplitude of ultrasonic vibrations and the inadmissibility of working in fixed modes of ultrasound fluctuations; 2) the “scoring” of intraocular structures by diffuse ultrasound and the cavitation effect observed upon contact of the working end of the ultrasound instrument with the moisture of the anterior chamber are an undesirable and potentially traumatic factor for the child’s eye, as developing children's eyes are much more sensitive to any damaging effects than the eyes of an adult.

 There is no information on the use of the method of ultrasonic trabeculectomy (UTE) in congenital glaucoma in children.

 The closest analogue of the present invention is a method for the treatment of congenital glaucoma in children - Ultrasonic sclerogoniotomy (USHT) (Method for the treatment of congenital glaucoma in children, SU 695666, 1975), the only ultrasonic antiglaucomatous operation used to date in children. The USGT method consists in perforating the outer wall of the Schlemm canal and trabeculae with an ultrasonic microscalpel at an oscillation frequency of 39-44 kHz and an amplitude of 10-15 microns in the form of two scleral sections 2-3 mm long along the projection line of the posterior half of the trabeculae. However, this method, despite its high efficiency (IOP compensation in 100% of operations over 6 months), has fairly narrow indications, being an ultrasonic analog of goniopuncture according to Broshevsky, i.e. palliative intervention performed only in front of the eyes with terminal stages of congenital glaucoma with organ-preserving purpose. The application of the USHT method in the main contingent of children with the initial and distant stages of congenital glaucoma is impossible.

 The objective of this invention is to provide a method for the surgical treatment of congenital glaucoma in children, combining the beneficial properties of ultrasound surgery (atraumatic, high-quality hemostasis without tissue burns, the absence of the need for additional diathermocoagulation hemostasis, prevention of excessive scarring, etc.) without undesirable effects of diffuse ultrasound on intraocular structures of the children's eye, with the microsurgical technique of the operation of trabeculectomy (TE), which has the widest indications in surgeons and congenital glaucoma.

 The technical result of the invention is the prevention of excessive scarring with prolonged compensation of IOP.

 The technical result is achieved through a combination of ultrasonic techniques for isolating and processing the surfaces of the scleral flap and mechanical removal of the strip of deep layers of the sclera and trabeculae, as well as techniques for suturing the surface tissues in the intervention area.

The proposed method is characterized by the following:
1) At the stages of cutting the scleral flap with an ultrasound scalpel and its separation with an ultrasound round knife, the working, "minimum effective" amplitude of the ultrasonic vibrations of the instrument is selected individually: with a gradual increase in amplitude from "0" to achieve sufficient effects: first a) cutting, and then, with a continued increase in amplitude, b) coagulating, but not exceeding an amplitude of 15 μm (2 position of the amplitude adjustment knob).

 Unlike the eyes of adult patients with glaucoma, the physical properties of the children's sclera of the eyes with congenital glaucoma (density, thickness, elasticity, etc.) are extremely individual. This is due, on the one hand, to the age-related characteristics of the sclera at various stages of incomplete development; on the other hand, the severity of secondary changes, stretching and thinning of the sclera due to the glaucomatous process. In order to avoid serious operational complications (perforation, etc.), work with a fixed amplitude of ultrasonic vibrations is unacceptable. The selection of the optimal amplitude is carried out individually, from "0", with a gradual increase in the amplitude until a sufficient cutting, and then coagulating, effect is achieved, but not exceeding the maximum amplitude (15 microns) allowed for this type of operation.

 2) The flat part of the ultrasound round knife aligns the inner surface of the scleral flap with an additional ultrasound effect (once “ironed” with 4–5 transverse movements the entire inner surface of the scleral flap) with an amplitude of ultrasonic vibrations of 10 μm. Additional ultrasound treatment of the inner surface of the scleral flap ensures the formation of a space under it (inner scleral fistula) with smooth walls completely treated by ultrasound exposure, which creates favorable healing conditions for all walls of the inner fistula with a lower risk of cicatricial obliteration. While with standard microsurgical TE during the flap separation on its inner surface, multiple semicircular micro-grooves with uneven edges parallel to the direction of tool movement are formed), which are the substrate for excessive scarring.

 3) Strips of the deep layers of the sclera 1x4 mm in the area of the projection of the Schlemm canal are excised exclusively by standard microsurgical instruments (blade - steel, diamond, etc.), without the use of ultrasound.

 The implementation of this stage of the operation without the use of ultrasound is fundamentally important: the contact of the ultrasound instrument with the IHC is prevented, which eliminates the unwanted “scoring” of the internal structures of the child’s eye (ciliary body, iris, lens, corneal endothelium) with diffuse ultrasound, which eliminates the risk of possible complications. This approach will not reduce the overall effectiveness of the ultrasound operation, because In the majority of unsuccessful fistulizing operations performed with standard microsurgical instruments, the organic obstruction to the outflow of the IHC is localized intrascleral and subconjunctival, the internal fistula is functionally consistent, which is also confirmed by our gonioscopic data. Thus, ultrasonic treatment of the internal fistula can be excluded from the technique as an optional stage of ultrasound operation associated with the undesirable effect of scattered ultrasound.

 4) At the stage of conjunctival suture, an additional 3-4 nodal sutures of the lower floor are applied - on the tenon capsule and subconjunctiva.

 In the postoperative period, children often have a discrepancy in the conjunctival incision (usually minimal), due to the pronounced filtration of the IHC with the formation of a high common filtration pad (which is most typical for ultrasound operations), restless behavior, and other factors. The imposition of additional sutures on the tenon capsule and subconjunctiva is necessary to ensure the tightness of the filter cushion with high-quality, anatomically correct floor adaptation of the edges of the conjunctival incision, prevention of possible complications associated with the discrepancy of the conjunctival incision (epithelial ingrowth, external filtration of the intraocular membrane with severe hypotension, etc.).

The method is as follows:
1. Under general anesthesia, the usual preparation of the surgical field is performed. A vector expander is installed, a bridle suture-holder is placed on the upper rectus muscle.

 2. Under the visual biomicroscopic control (operating microscope), the conjunctiva is cut using microsurgical scissors in the upper outer quadrant 8 mm from the limb, parallel to it, 10-15 mm long; otseparovyvat ("blunt way", pushing the branches of the scissors) conjunctival flap to the zone of projection of the limb. Exceptionally gentle tactics are observed with respect to the subconjunctiva and episclera (scleral surface cleaning with a scraper and vascular diathermocoagulation are not performed). With standard microsurgical trabeculectomy, the need for such cleaning of the scleral flap was, first of all, the stage of hemostatic measures to prevent bleeding from the vessels of the episclera during the formation of the scleral flap. However, it has now been proven that massive excision of the subconjunctiva and episclera over the scleral flap is undesirable, because leads to its subsequent ischemia, the formation of a significant wound surface, stimulating the formation of coarse-fibrous connective tissue in the intervention zone and cicatricial obliteration of the created filtration pad (Wessels I. F. et al. Avoiding Tenon's capsule. // Ophthalmology. 1998 Jun; 105 (6): 942).

 Non-thermal ultrasound coagulation, simultaneous with tissue dissection (see below), provides high-quality hemostasis when crossing medium-sized vessels, without causing thermal burns of tissues with a massive release of inflammatory mediators from thermally destroyed tissues. There is no need for additional diathermocoagulation when performing our technique.

 Performing this stage according to the proposed method will significantly reduce the invasiveness of the operation, preserve the episclera as the only source of physiological blood supply to the sclera, which together with the direct antiproliferative effect of low-frequency ultrasound will prevent excessive scarring in the intervention area.

 3. Visually, in the perilimbal region, a rectangular site of localization of the future scleral flap is selected, 4x5 mm in size, preferably devoid of large vessels, and also located outside the areas of previous antiglaucomatous operations (if carried out).

 4. Using an ultrasound microscalpel (see figure 1 - item 1) of the device UZH-201, a U-shaped sclera flap 4x5 mm (position 2) is cut out, with a base to the limb, to 2/3 of the sclera thickness. The minimum effective amplitude of ultrasonic vibrations is selected individually: from "0", with a gradual increase in amplitude (by turning the knob for adjusting the amplitude of ultrasonic vibrations of the UZH-201 apparatus) to achieve a sufficient cutting and then coagulating effect, but not exceeding the maximum allowable for this type of amplitude operation (15 μm).

 5. An ultrasound round knife (see figure 2 - item 3) of the device UZH-201 detaches the scleral flap (item 4) with a thickness of approximately 2/3 of the sclera. The amplitude of ultrasonic vibrations is selected according to the principle described above.

 6. The flat part of the ultrasound round knife (see figure 3. - item 5) carry out the alignment of the inner surface of the scleral flap (item 6) with an additional ultrasound effect (“ironed” once with 4 to 5 transverse movements the inner surface of the scleral flap) with an amplitude of ultrasonic vibrations of 10 μm. With significant thinning of the sclera, this stage may not be carried out.

 7. Diaphanoscopically clarify the localization of the CPC and corneoscleral trabeculae. Diaphanoscopy is performed by applying to the cornea a sterile applanation tip of the light guide of the diaphanoscope with the coaxial illumination of the surgical microscope turned off.

 This stage is extremely important during eye operations with congenital glaucoma, when significant stretching of the cornea and limbus, an unpredictable change in the ratio of the structures of the drainage zone are often observed.

 8. A standard microsurgical blade (sapphire, steel, etc .; see Fig. 4. - item 7) excise a strip of deep layers of the sclera and corneoscleral trabeculae 0.5x4 mm (item 8). When the iris is inserted into the surgical incision (and / or its anterior attachment), basal iridectomy is performed with microsurgical scissors.

 9. The U-shaped scleral flap is repaired, fixed with 2 interrupted sutures in the corners (Vikril, 8-0). With a sharp contraction of the flap, which occurs in front of the terminal stages of congenital glaucoma with significant stretching of the membranes, it is advisable to impose additional 1-2 nodal sutures to achieve uniform tension of the scleral flap.

 10. Stitches are placed on the conjunctival incision: 3-4 additional nodal sutures on the lower floor - on the subconjunctiva and tenon capsule (Vikril, 7-0); continuous external suture on the conjunctiva (Vikril, synthetics 7-0).

 The operation is completed in the standard way (a solution of Dexazone 0.3 and Gentamicin 0.2 is administered under the conjunctiva; 30% Albucid ointment is placed over the eyelids; a binocular sterile dressing is applied).

 Example 1. Patient A., age 5 months. Diagnosis OD: congenital initial uncompensated glaucoma; congenital coloboma of the iris and choroid; OS: risk group for congenital glaucoma (goniodysgenesis 1 tbsp.). Common diseases: PEP, cm muscle dystonia.

 On admission: cornea OD elongated, 12x11 mm (exceeds the norm by 1-2 mm), with slight swelling and opalescence of the stroma; OS corneal diameter corresponds to age (10 mm). OD - for 6 hours - a complete coloboma of the iris, the pupil has the shape of a "keyhole". The lens and art. the body is optically transparent. On the fundus - an extensive coloboma of the choroid, occupying the lower 2/5 of the fundus, optic nerve disc within the coloboma, pale pink, with a grayish tint, the borders are clear, with a slight shift of the vascular bundle to the nasal side. OS - optical media are transparent, in Sec. bottom without pathology.

 Gonioscopy: OU - high attachment (at 1/2 trabeculae) of the iris. Sections of thinning of the iris root, alternating with areas of black pigment, root with neovascularization, bedding of embryonic translucent veil-like tissue. Significant differences in the gonioscopic picture of OU were not detected.

 vis OD ≥ 0.05; vis OS ≥ 0.01 (it is impossible to determine more precisely by age; subjectively - forced position of the head, watches for bright objects with 25-50 cm, preferably with the left eye). IOP OD - 24 mm Hg; OS - 19 mmHg Art. (in anesthesia, according to Maklakov, at the maximum drug regimen OD - Pilocarpine 1% x3 s.d., Arutimol 0.25% x2 s.d., Trusopt 2% x2 s.d., Diacarb 0.04 inward 1 p. d.).

 Topography (TNTs-100): OD - Po = 29 mm Hg, C = 0.15; F = 2.8; KB = 196; OD - Po = 47 mm Hg, C = 0.21; F = 2.73; KB = 110 (OD - Po uncompensated, moderate retention to the outflow of HPV).

 Sonography. PZO / PC: OD = 22.8 mm / 2.9 mm; OS = 20.4 mm / 3.8 mm (PZO OD exceeds the size of the paired eye by 2.4 mm and the age norm by 3 mm).

 Total ERG. A / B / BS / CS OD - 50 μV / 90 μV / 40 Hz / 30 Hz; OS - 50 μV / 90 μV / 40 Hz / 30 Hz (OD - subnorm. ERG, moderate, pathogenic. Retina; OS - normal).

 The absence of compensation for IOP OD at the maximum possible antihypertensive mode with a gonioscopically determined organic obstruction to the outflow of IHV, the presence of a combined developmental anomaly (coloboma of the iris and vascular), pathognomonic of one of the forms of congenital glaucoma, and initial glaucomatous changes in the eye, were an absolute indication for surgical anti-glaucomatous .

 Given the rather timely appeal of the child’s parents for help, the initial stage of the glaucomatous OD process, the presence of initial anatomical and functional glaucomatous changes, the prognosis for vision and disease in this child was regarded as more favorable. The prognosis, especially in this case, depended directly on the ability of a fistulizing antiglaucomatous operation to provide long-term compensation of IOP with the prevention of excessive scarring of the filtering bag in the postoperative period.

The operation on OD - Combined ultrasound trabeculectomy:
General anesthesia An enlarger is installed on the right eye, a bridle suture-holder is placed on the upper rectus muscle. The conjunctiva was cut with microsurgical scissors in the upper outer quadrant 8 mm from the limb, parallel to it, 10 mm long; Separated in a dull way. A rectangular section of the sclera 4x5 mm, with a base to the limb, devoid of large vessels is outlined. Scraping of the episclera was not carried out. An ultrasound microscalpel of the UZH-201 apparatus is cut into a U-shaped sclera flap 4x5 mm, with a base to the limb, to 2/3 of the sclera thickness. The working amplitude of ultrasonic vibrations is selected by gradually increasing the amplitude of ultrasonic vibrations from "0" until a sufficient cutting and coagulating effect appears and amounted to 8-10 microns). An ultrasound round knife of the UZH-201 apparatus detached a scleral flap with a thickness of approximately 2/3 of the sclera (the amplitude of the ultrasonic vibrations was selected according to the principle described above, was 10-12 microns). The lightness and bloodlessness of the incisions during the isolation and separation of the scleral flap, characteristic of ultrasound instruments, was noted. Ultrasound coagulation of the edges of the incisions ensured high-quality hemostasis; additional diathermocoagulation was not performed. The flat surface of the ultrasound round knife aligns the inner surface of the scleral flap with an additional ultrasound effect (the amplitude of the ultrasonic vibrations is 10 μm). The localization of the CPC and corneoscleral trabecula was determined diaphanoscopically. In the projection zone of the CPC, a strip of deep layers of the sclera and corneoscleral trabecula 0.5x4 mm is excised with a microsurgical blade. Microsurgical scissors performed in a PC performed basal iridectomy. The U-shaped scleral flap is repaired, fixed with 2 interrupted sutures in the corners (Vikril, 8-0). On the lower floor of the conjunctiva incision (tenon capsule, subconjunctiva) 3 additional nodal sutures were applied (Vikril, 7-0); outside the conjunctiva a continuous suture was applied (synthetics 7-0). C / c injection of Dexazone 0.3 and Gentamicin 0.2; for the eyelids lay Albucid ointment 30%; a binocular sterile dressing was applied. During the operation and the postoperative period without complications. The clinical picture was calm, eye tissue reactivity in the first 4 days after surgery (the conjunctiva was slightly swollen, there were no pronounced edema and hyperemia of the filtering pad (AF) and the edges of the conjunctival incision, its yellowish hemolytic hue was observed during TE with diathermocoagulation hemostasis. 10 days after surgery, the external conjunctival suture was removed; the edges of the incision are well adapted; a thick-walled, widespread, well-vascularized AF forms; et (fluorescein test is negative. IOP OD at discharge - 1 palp. (without medical mode).

 During the control examination under anesthesia (7 months after the operation), it was found: OD is calm, widespread AF is formed, the diameter of the cornea is stabilized, and corneal edema is absent. Improved vision OD: vis OD ≥ 0.04; vis OS ≥ 0.04 (it is impossible to determine more precisely by age; there is no previously observed forced position of the head; the preferred nature of vision with the left eye is not so obvious).

 IOP OD - 16 mm Hg; OS - 19 mmHg (in anesthesia, in the OU drug regimen - Pilocarpine 1% x1 wd, - prophylactically, taking into account goniodysgenesis and anterior iris attachment to OU).

 Topography (TNTs-100): OD - Po = 14.4 mm Hg, C = 0.37; F = 1.69; KB = 36; OD - Po = 17.5 mm Hg, C-0.27; F = 1.97; KB = 64.

 Sonography. PZO / PC: OD = 20.9 mm / 2.56 mm; OS = 21.2 mm / 3.81 mm.

 Total ERG. A / B / BS / CS OD - 60 μV / 100 μV / 40 Hz / 40 Hz; OS - 70 μV / 200 μV / 40 Hz / 40 Hz.

 T. about. , according to research, 7 months after the operation, a qualitative compensation of the IOP of the operated eye was noted; corneal diameter, PZO stabilized, corneal syndrome completely disappeared, there is a slight improvement in OD functions, which indicates compensation for the glaucomatous process.

 At the last outpatient examination of the child 1.5 years after the operation, stable compensation of IOP for OD is maintained. The good condition of the filtration cushion (widespread, thick-walled, well vascularized) and gonioscopically confirmed viability of the internal fistula indicate the absence of clinical signs of excessive scarring in the intervention area and the fundamental possibility of a significantly longer compensation of the intraocular pressure with a favorable prognosis for this patient.

 Thus, the proposed method allows to achieve a longer compensation of IOP with the prevention of excessive scarring in the eyes of children with congenital glaucoma due to a combination of ultrasonic and mechanical effects in the area of operation.

Claims (1)

 A method for the surgical treatment of congenital glaucoma in children, including ultrasound, characterized in that a penetrating sinusotrabeculectomy is performed, while the superficial scleral flap is cut out and separated using an ultrasound scalpel and an ultrasound round knife with a gradual increase in the amplitude of ultrasonic vibrations from 0 to the minimum value amplitude sufficient to obtain the necessary cutting and coagulating effect, after separating this flap, its inner surface is leveled with an additional ultrasound Corollary, and a strip of deep layers of sclera and corneascleral trabeculae dissected blade for closure of conjunctival impose additional nodal joints on subkonyunktivu and Tenon's capsule.

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