| ObjectiveTo investigate the effects and mechanism of pars plana filtration technique on glaucoma model and refractory glaucoma patients, and to further study its effects on ocular region histopathology, thereby to identify pars plana filtration technique which may be valuable as therapeutic method for glaucoma, and thus to provide new thoughts and approaches for future study.Methods1．Intraocular hypertension model study: For the establishment of the model of experimental chronic intraocular hypertension of a rabbit, anterior chamber injection of carbomer and posterior chamber injection ofα-chymotrypsin were performed respectively on rabbits to induce glaucoma.2．Experimental animal study: When Karbomer hypertension rabbits were treated bypars plana filtration surgery, the ciliary body, scleral flap, conjunctival flap and optic nerve were observed by UBM, B ultrasound, light and electron microscope. The fluorecin isothiocyanate-bovine serum albumin (FITC-BSA) was used, after pars plana filtration technique was observed.3．Clinic study: The retrospective study was conducted to evaluate 31 (34 eyes refractory glaucoma patients who were treated by pars plana filtration technique starting from April 2005 to January 2007 period in our hospital. The IOP, eyesight, ocular region histopathology was observed.Results1．Experiment on chronic ocular hypertension model in rabbits(1) Carbomer group: IOP heighten in ten eyes after injected by Carbomer on 1 day anddescend on 2ndand 3rdday, then heighten again. IOP was kept on higher ocular hypertensionon 7 day, continued over 30 days, and began to descend on 45thday, but was still abovenormal level. Until to 60thday, eight eyes IOP descended to normal level. The IOP ofhighest is 51．6mmHg and over 30mmHg in general. One eye didn't heighten anymore after 1st day. This group's success rate is 90%.(2) Chymotrypsin group: The IOP heightened slightly in 3 eyes on 15th day and passed over normal level on 30th day. These 3 eyes stayed on higher ocular hypertension for about 20 days. The IOP of highest is 32mmHg and 20-30mmHg in general. This group's success rate is 30%.2．Clinic observation of experimental ocular hypertension models treated by pars plana filtration technique(1) IOP contrast result: Nine model eyes IOP were reduced to normal (less than 23mmHg) with pars plana filtration surgery, one eye IOP was 26．5 to 36．0mmHg at the postoperative first month and reduced to 17．1mmHg at the postoperative 2nd month and to 10．3mmHg at the postoperative 3rd month. The surgery group had lower mean IOP than the carbomer model group at all postoperative visits, and the differences were significant.(2) Surgery eye clinical situation: On the postoperative 3day, conjunctive was congested and oedematous; tresis vulnus was closed well; cornea had cloudiness and oedemas which just like the control group; bleb characteristics was clear; there was floccular turbidness in anterior chamber; the deep of the anterior chamber was about 1CT; iris surface vasodilatation; lens were clear; the vitreous body and eyeground were not to be seen. After one month, the above-mentioned inflammatory reaction had improved and after 3 months disappeared. After the postoperative half a year, the inflammatory reaction couldn't be found, the eyeball condition was normal, except that the pupil light reflex was weak. One eye had vitreous opacification at the postoperative 2 months and didn't aggravate at half a year by funduscope.(3) Surgery eye ultrasonic inspect result: UBM showed 9 eyes filtered aisles were smooth and 1 eye filtered aisle was conglutination at the postoperative 3rd month. B ultrasonic showed 1 eye had vitreous opacification at the postoperative first month and aggravated at the postoperative 3rd month, but didn't get worse at the postoperative 6th month.3．Histomorphology observation of experimental ocular hypertension rabbits treated by pars plana filtration technique(1) Light microscope result: Surgery group: On postoperative 1st day, conjunctive was congested and oedematous; there was inflammatory cell infiltration in conjunctive, sclera, ciliary body around the incision; there was some hemorrhage on operative incision. On postoperative 1 month, the above-mentioned inflammatory reaction had improved. There no obvious expansion on the eyeball wall. The optic nerve oligodendroglias were increased and myelinolysis was more lightened than of the control group. At the postoperative half year and one month, pigment granules were disseminated, some of which in scleral flap gap. There were no significant differences on optic nerve between 1 month and 3 months. At the postoperative half a year, there was limited conglutination in scleral flap gap and intra-incision. Cyclitic membrane was found at the surface of ciliary processes in one eye which dragged the ciliary epithelium detached. Control group: As injected to anterior chamber, Carbomer became a kind of material just like gelatin. After injected carbomer 1 week, eyeball was expanded slightly, and there was inflammatory cell infiltration in cornea and conjunctive, and the chamber was occluded, optic nerve demyelinated, and there was interstitial edema around the blood vessel in optic nerve. During follow-up period, the control group inflammatory cell infiltration was lighter and shorter than the surgery group's, but optic nerve was more damaged than the surgery group's. After half a year with injected carbomer, some optical cartridges had disappeared and were replaced by glue framework, and there was some irregular vacant area in these frameworks.(2) Electron result: Normal rabbit's eye: Ciliary body neurepithelium and pigment epithelium are lined up in order; cellular membrane is integrated; neurepithelium endochylema is plentiful and includes redundant mitochondrium and endoplasmic reticulum. There are plentiful round pigment granules in pigment epithelial cell. Optic nerve neuraxis line up in order; the micropipe and microfilament can be found in nerve easily. In surgery group: At the postoperative initial stage, vacuole could be found in ciliary body chromatophore, some mitochondria were swollen and crista was broken, some optic nerve axons had swelling, vacuole was in medullary, micrangium engorgement, the all above phenomenon had stayed on for about one month and then lightened by degrees. At the postoperative half a year, the pigment granule disseminated, endocytoplasmic reticulum raritas in endochlema, a few of marcid caryon and few of thicken medullary sheath could be found, most of optic tract was lined up in order. In contrast to control group, surgery group ciliary bodies were damaged badly but the optic nerve was damaged slightly.4．Experimental study of aqueous humor out-flow pathwayThere are three out-flow pathways of pars plana filtration technique:(1) Aqueous humor outflow from sclera incision to infra-conjunctiva was absorbed by conjunctiva vessel. (2) Aqueous humor outflow in Fantana gap by angle of anterior chamber and was absorbed by cavemous tissue. (3) Uverescleral pathway: aqueous humor outflow from epichoroidal space, ciliary body, pro-sclera and post-sclera to chorioid and was absorbed.5．Clinic research of pars plana filtration technique (1) Intraoperative state: all patients operation was accomplished successfully, 5 eyes had discomfort sometime in professional jargon, and 26 eyes had vitreous leakage.(2) Postoperative IOP : 29 eyes mean IOP was 6．54 mmHg, 3 eyes IOP ranged from 20 to 33mmHg, 2 eyes couldn't be checked up for corneal edema on 1st day; 30 eyes mean IOP was 6．88mmHg and 4 eyes IOP ranged from 22 to 25mmHg on 1wk. Follow-up phase: 20 eyes mean IOP was 8．36mmHg and one eye IOP was 24mmHg on 1 month; 14 eyes mean IOP was 15．21 mmHg and one eye was 26mmHg on 3month; 13 eyes mean IOP was 14．56mmHg, one eye IOP was 25mmHg, one eye could not be checked up on half a year; 11 eyes mean IOP was 13．35mmHg. One eye did not check to see the doctor, the eye ball was swollen and had engorgement but no pain after one year. 4 eyes IOP were over 21 mmHg in which 2 eyes were NVG and 2eyes were CAG There were 3 eyes that took the filtrated flap conglutination solution technique and 1 eye took phaco-IOL implantation operation in other hospital.(3) Postoperative visual acuity: 19 NIL eyes had no change; in 15 eyes with eyesight, 4 eyes were improved, 8 eyes were stable and 3 eyes descended.(4) Postoperative ocular state: All eyes anterior chamber had deepened on different degrees; 9 eyes had seston and 2 eyes had cellulose in anterior chamber, all these inflammatory reactions were absorbed in 3 days. Hyphema occurred in 5 eyes which were transient. 2 eyes had part of choroidal detachment which was transient at one and three months differently. One eye had phthisis.Conclusion1．Experimental glaucoma model induced by Carbomer has the advantages of producing moderate and sustained IOP elevation.2．Pars plana filtration technique provides reduction of IOP of experimental hypertension model, and has little disadvantage. The research indicates it may have improvement on the effect level with antifbrotic agents in pars plana filtration technique.3．Pars plana filtration technique has three pathways on reduction of IOP: conjunctiva blood vessel, angle of anterior chamber and Uverescleral pathway.4．Pars plana filtration technique is one of the alternative and effective methods for the treatment of refractory glaucoma. It can be widely used in clinics.Keywords:Pars plana filtration technique; glaucoma; experimental hypertension model; traditionalChinese medicine; pathology... |
PDF Full Text Request