Abstract
Purpose
To examine the relationship between the extent of the incision in the Schlemm canal during suture trabeculotomy (S-LOT) for open-angle glaucoma and the associated reduction in intraocular pressure (IOP).
Methods
Forty-eight consecutive eyes (primary open-angle glaucoma: 28; exfoliation glaucoma: 20) scheduled to undergo S-LOT were studied. A 320-degree opening in the Schlemm canal was planned when total circumferential cannulation had been achieved, and the remaining 40-degree region under the scleral flap was not incised. When the cannulation was incomplete, the canal was incised up to the point reached by the cannula, and the extent of the incision was measured. Logistic regression analysis was performed to identify potential predictors of surgical success (IOP ≤ 15 mmHg).
Results
A 320-degree incision was achieved in 23 eyes, and the mean extent of the incision was 275 ± 52.3°. The mean IOP fell from 34.0 ± 8.8 mmHg at baseline to 14.5 ± 4.0 mmHg at 1 year postoperatively (P < 0.0001). An IOP reduction of ≥30% was achieved in 46 eyes. Simple correlation analysis indicated that the extent of the incision in degrees did not correlate with IOP or with the reduction in IOP at 1 year postoperatively (P = 0.7665 and 0.693, respectively). Lower preoperative IOP values and concomitant cataract extraction were found to be associated with surgical success.
Conclusions
The extent of the incision in the Schlemm canal during S-LOT does not correlate with postoperative reduction in IOP.
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References
Tanihara H, Negi A, Akimoto M, Terauchi H, Okudaira A, Kozaki J, et al. Surgical effects of trabeculotomy ab externo on adult eyes with primary open angle glaucoma and pseudoexfoliation syndrome. Arch Ophthalmol. 1993;111:1653–61.
Honjo M, Tanihara H, Negi A, Hangai M, Taniguchi T, Honda Y, et al. Trabeculotomy ab externo, cataract extraction, and intraocular lens implantation: preliminary report. J Cataract Refract Surg. 1996;22:601–6.
Honjo M, Tanihara H, Inatani M, Honda Y, Ogino N, Ueno S, et al. Phacoemulsification, intraocular lens implantation, and trabeculotomy to treat pseudoexfoliation syndrome. J Cataract Refract Surg. 1998;24:781–6.
Tanito M, Ohira A, Chihara E. Surgical outcome of combined trabeculotomy and cataract surgery. J Glaucoma. 2001;10:302–8.
Tanito M, Ohira A, Chihara E. Factors leading to reduced intraocular pressure after combined trabeculotomy and cataract surgery. J Glaucoma. 2002;11:3–9.
Chin S, Nitta T, Shinmei Y, Aoyagi M, Nitta A, Ohno S, et al. Reduction of intraocular pressure using a modified 360-degree suture trabeculotomy technique in primary and secondary open-angle glaucoma: a pilot study. J Glaucoma. 2012;21:401–7.
Minckler DS, Baerveldt G, Alfaro MR, Francis BA. Clinical results with the Trabectome for treatment of open-angle glaucoma. Ophthalmology. 2005;112:962–7.
Francis BA, See RF, Rao NA, Minckler DS, Baerveldt G. Ab interno trabeculectomy: development of a novel device (Trabectome) and surgery for open-angle glaucoma. J Glaucoma. 2006;15:68–73.
Francis BA, Minckler D, Dustin L, Kawji S, Yeh J, Sit A, et al. Combined cataract extraction and trabeculotomy by the internal approach for coexisting cataract and open-angle glaucoma: initial results. J Cataract Refract Surg. 2008;34:1096–103.
Ahuja Y, Ma Khin Pyi S, Malihi M, Hodge DO, Sit AJ. Clinical results of ab interno trabeculotomy using the trabectome for open-angle glaucoma: the Mayo Clinic series in Rochester, Minnesota. Am J Ophthalmol. 2013;156:927–35.
Temkar S, Gupta S, Sihota R, Sharma R, Angmo D, Pujari A, et al. Illuminated microcatheter circumferential trabeculotomy versus combined trabeculotomy-trabeculectomy for primary congenital glaucoma: a randomized controlled trial. Am J Ophthalmol. 2015;159:490–7.
Bill A, Phillips CI. Uveoscleral drainage of aqueous humour in human eyes. Exp Eye Res. 1971;12:275–78.
Kanski JJ. Clinical ophthalmology: a systemic approach. 2nd ed. Oxford: Butterworth-Heinemann Ltd; 1989. p. 138.
Buller C, Johnson D. Segmental variability of the trabecular meshwork in normal and glaucomatous eyes. Invest Ophthalmol Vis Sci. 1994;35:3841–51.
Johnson M, Chan D, Read AT, Christensen C, Sit A, Ethier CR. The pore density in the inner wall endothelium of Schlemm’s canal of glaucomatous eyes. Invest Ophthalmol Vis Sci. 2002;43:2950–5.
Rosenquist R, Epstein D, Melamed S, Johnson M, Grant WM. Outflow resistance of enucleated human eyes at two different perfusion pressures and different extents of trabeculotomy. Curr Eye Res. 1989;8:1233–40.
Swaminathan SS, Oh DJ, Kang MH, Ren R, Jin R, Gong H, et al. Secreted protein acidic and rich in cysteine (SPARC)-null mice exhibit more uniform outflow. Invest Ophthalmol Vis Sci. 2013;54:2035–47.
Chen PP, Lin SC, Junk AK, Radhakrishnan S, Singh K, Chen TC. The effect of phacoemulsification on intraocular pressure in glaucoma patients: a report by the American Academy of Ophthalmology. Ophthalmology. 2015;122:1294–307.
Hayashi K, Hayashi H, Nakao F, Hayashi F. Effect of cataract surgery on intraocular pressure control in glaucoma patients. J Cataract Refract Surg. 2001;27:1779–86.
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S. Manabe, None; S. Sawaguchi, None; K. Hayashi, None.
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Manabe, Si., Sawaguchi, S. & Hayashi, K. The effect of the extent of the incision in the Schlemm canal on the surgical outcomes of suture trabeculotomy for open-angle glaucoma. Jpn J Ophthalmol 61, 99–104 (2017). https://doi.org/10.1007/s10384-016-0487-4
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DOI: https://doi.org/10.1007/s10384-016-0487-4