Nonpenetrating deep sclerectomy (NPDS) has been performed since the 1990s using various techniques to maintain the aqueous decompression space, such as collagen-based and autologous implants. However, increased expense and the possibility of fibrosis with implants have been reported. A 1-year prospective investigation follows up on the initial 3-month trial that introduced a novel step known as sub-flap Ahmed’s suture, and demonstrates outcomes of deep sclerectomy were enhanced by 30%, as reported in Eye.
Sub-flap mattress sutures are applied with a 10/0 nylon nonabsorbable monofilament that may cause less unfavorable cell response. It is placed “under and reaching beyond the edges of the superficial scleral flap,” acting as a “hinge” to improve intraocular pressure (IOP) reduction. Ahmed’s suture is a low-cost addition to NPDS that elevates the proximal superficial flap to lower stress on trabeculo-Descemet’s membrane and allow better outflow, the study explains. Investigators evaluated 2 randomized cohorts comparable in age, sex, preoperative IOP, and baseline medications; 52 eyes underwent surgery including the added suture, and 51 eyes received conventional NPDS.
Each group comprised patients with the following disorders: primary open-angle glaucoma (POAG), pigmentary glaucoma, and juvenile open-angle glaucoma (JOAG). Examinations revealed significantly lower IOP in participants who received the modified procedure, after 1 week (P =.001), 3 months (P =.001), 6 months (P =.002), 9 months (P =.027), and 12 months (P =.029), compared with those who underwent standard NPDS.
Further, comparison between cohorts regarding the percentage of IOP reduction from pre-op values was highly significant in favor of modified NPDS at 3 months (P =.001), 6 months (P =.001), 9 months (P =.003), and 12 months (P =.006).
Fewer additional IOP-lowering interventions were needed by those undergoing deep sclerectomy including Ahmed’s suture. In the modified surgery cohort, 12% needed goniopuncture and 4% required needling, as well as an average of 0.2 added post-op medications, compared with the conventional procedure group, for whom 18% underwent goniopuncture, 12% needling, and 0.5 medications. Complications for both sets were “negligible,” and the technique has proved safe, according to the analysis.
Complete success was defined as IOP from 6 mm Hg to 18 mmHg without medication for 12 months, and qualified success as this IOP level while also taking topicals. For individuals obtaining the sub-flap suture, 81% of eyes achieved complete success and 17% qualified success, compared with complete success in 69% of eyes receiving conventional NPDS and 29% qualified success.
Previous research has found lower post-surgery IOP may be a reliable indicator of better long-term effectiveness after deep sclerectomy. In the current investigation, multivariate regression analysis for risk factors found reduced IOP at 1 week was related to lower reading at 12 months. Therefore, early post-op IOP after Ahmed’s suture revealed an enhanced 1-year success rate.
Preoperative mean age of the modified deep sclerectomy cohort was 38.1±13.3 years, compared with 38.4±15.0 years in the conventional surgery group. The relatively short follow-up period was a limitation of the study, as was exclusion of statistical analysis by glaucoma severity. Notably, the trial demonstrated success in juvenile-onset glaucoma, who often present to clinics with more advanced disease.
Abdelrahman AM, Hassan LM, Habib MM. Non-penetrating deep sclerectomy with the sub flap (Ahmed’s) suture: a 12-month comparative study. Eye. Published online May 31, 2022. doi:10. 1038/s41433-022-02102-6