Minimally Invasive Micro Sclerostomy (MIMS) Procedure: A Novel Glaucoma Filtration Procedure

Abstract

Précis: Intermediate-term results suggest that ab interno Minimally Invasive Micro Sclerostomy (MIMS) stent-less subconjunctival filtration procedure is a promising treatment option for patients with open-angle glaucoma (OAG).Purpose: MIMS is a novel ab interno, stent-less, subconjunctival filtration procedure. This study set to investigate the safety, performance, and efficacy of MIMS in OAG patients. Methods:Prospective, open-label, single arm clinical trial with intrasubject comparisons. Study participants were adults with OAG who were candidates for a filtration procedure. Patients were operated by a single surgeon (A.A.) in Chennai, India. Following mitomycin-C pretreatment, ab interno MIMS procedure was performed alone or combined with phacoemulsification surgery. Procedure-related complications and adverse events were assessed. Primary outcomes: patients (%) achieving an intraocular pressure (IOP) ≥ 5 mm Hg and ≤ 18 mm Hg, and an IOP reduction of > 20% as compared with baseline, with or without hypotensive medications, with no need for recurrent surgery.Results: Twenty-one phacoemulsification-MIMS and 10 standalone MIMS procedures were performed. Mean age was 63.94 ± 6.33 years. Mean duration of MIMS was 1:58 ± 0:25 (min: s). Scleral tunnels were achieved in all cases. No device malfunctions, intraoperative complications, or serious adverse events were reported. Five (16.12%) patients presented with iris clogging 1 to 24 weeks following procedure. Two were treated with laser and 3 required trabeculectomy. Mean IOP change from baseline at 24 weeks was 47.4% (31.2 to 16.4 mm Hg, P < 0.0001, n = 23). The mean difference was −14.8 mm Hg (95% confidence interval: −17.6, −11.9) with no statistically significant differences between groups. Qualified success was achieved in 21 (84%), 17 (74%), and 13 (93%) after 12, 24, and 52 weeks, respectively. Complete success was achieved in 17 (68%), 13 (57%), and 8 (57%) after 12, 24, and 52 weeks, respectively. Conclusions:The interim results suggest that MIMS procedure may be a simple and effective surgical option for early OAG patients requiring target IOP in high teens although iris clogging of incision site is the major concern with this procedure.

Recent Advancements in Glaucoma Surgery—A Review

“…MIMS is being touted as a MIGS procedure without foreign body-related complications, such as conjunctival erosions, corneal endothelial cell loss, stent migration, or extrusion, while delivering an IOP reduction that resembles existing subconjunctival MIGS. In an early clinical trial with 31 eyes, short-term IOP was lowered, similar to that expected with subconjunctival filtering MIGS [ 117 ]. Iris clogging of the internal sclerostomy causing high IOP spikes was the most common and concerning complication, and some of these could not be cleared with laser [ 117 ].…”

“…Minimally Invasive Micro Sclerostomy (MIMS) is an ab interno, stent-free, subconjunctival filtration procedure [ 117 ]. The MIMS handpiece consists of a 600 µm needle that rotates around its longitudinal axis and has been designed to carve a permanent tunnel near the corneoscleral junction to connect the AC with the subconjunctival space.…”

Hydroxycamptothecin regulates scar formation of the filtration channel under scleral flap by inhibiting the proliferation of scleral fibroblasts

“…This is mainly because tissue trauma caused by surgery causes the release of a variety of cytokines and inflammatory mediators, which stimulate the proliferation and migration of fibroblasts, leading to poorly functioning or even closed channels established by filtration surgery [ 31 , 32 ]. The wound healing process in filtration surgery is similar to the pathophysiological process after general surgery [ 33 , 34 ]. Therefore, some researchers believe that the 14 days following a glaucoma filtration surgery is a critical period for inhibiting scar formation.…”

Minimally Invasive Glaucoma Surgery: Latest Developments and Future Challenges

“…However, the IOP gradually returned to the preoperative level after approximately 14 weeks and 5 weeks, respectively. Subsequently, a prospective single-arm clinical trial with intrasubject comparisons achieved a 47.4% IOP reduction (31.2–16.4 mm Hg, P < 0.0001) from baseline to 24 weeks in 23 patients who underwent MIMS alone or MIMS combined with phacoemulsification 205 . The major complication of the procedure is iris clogging of the incision site and subsequent laser or trabeculectomy may be required.…”

“…Subsequently, a prospective single-arm clinical trial with intrasubject comparisons achieved a 47.4% IOP reduction (31.2-16.4 mm Hg, P < 0.0001) from baseline to 24 weeks in 23 patients who underwent MIMS alone or MIMS combined with phacoemulsification. 205 The major complication of the procedure is iris clogging of the incision site and subsequent laser or trabeculectomy may be required. More recent unpublished data demonstrated a 38% IOP reduction from baseline without major complications in 93 out of 120 patients who completed a 1-year follow-up.…”