Endoscopic Cyclophotocoagulation (ECP)
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ECP has been utilized in a wide variety of glaucoma types including primary open-angle, angle-closure, pigmentary, neovascular, traumatic, pediatric and other refractory glaucoma.
With the improvement of laser technologies, the use of scleral transillumination, endoscopic techniques, and the accuracy of treatment location have challenged preconceived notions as to where cyclophotocoagulation fits into the glaucoma treatment armamentarium. Evidence is growing that supports cyclophotocoagulation as a viable treatment in patients with mild to moderate and medically controlled glaucoma with good vision potential. At this time however, no long-term randomized prospective studies comparing ECP to trans-scleral cyclophotocoagulation and trabeculectomy exist.
Most recently, ECP has been increasingly utilized in conjunction with cataract extraction as an initial glaucoma surgery. Early studies seem to support that ECP is effective in lowering IOP and suggest an excellent safety profile in this setting. Visually significant cataract is commonly the driving force in the decision to proceed with phaco-ECP in patients with both cataract and glaucoma.
Despite extensive positive anecdotal experience, more prospective well-controlled long-term studies are necessary to more accurately determine the actual benefits and indications of ECP. Intraocular pressure spikes, increased postoperative inflammation, intraocular lens dislocation, and long-term efficacy remain legitimate concerns.
With endoscopic cyclophotocoagulation, ciliary processes may be accessed from either a limbal or a pars plana approach. Assessment of lens and vitreous status is important in determining an ECP surgical plan. Ciliary processes may be accessed from an anterior approach in phakic, pseudophakic, and aphakic eyes. The limbal approach is generally recommended in patients undergoing ECP combined with cataract surgery and intraocular lens implantation. The incision should be at least 1.5–2.2 mm in length. Both clear corneal and the scleral tunnel incisions commonly used in cataract surgery provide adequate access for the endoscope. A pars plana approach can be considered in pseudophakic patients and provides the most complete view of the ciliary processes. However, an anterior vitrectomy must be performed if this approach is used. Topical, peribulbar and retrobulbar block techniques all provide acceptable anesthesia.
To perform ECP, the anterior chamber must be stabilized and the ciliary sulcus must be deepened with an ophthalmic viscoelastic device (OVD). Healon GV may be the most advantageous OVD to use in this setting. Other cohesive OVD such as Healon and Provisc may not be able to maintain the space in the ciliary sulcus well enough for ECP. Healon 5 would maintain space well but may increase the risk and severity of early postoperative IOP spikes. Dispersive OVD such as Viscoat and Amvisc do not maintain space well and also have a tendency to absorb laser energy.
One of the great advantages of ECP over transscleral cyclophotocoagulation techniques is the ability to deliver laser energy in a highly titratable fashion to the ciliary processes. The optimum tissue effect is to whiten the ciliary process and effect visible tissue shrinkage. Photocoagulation is applied with the endoscope 1.0–3.0 mm from the ciliary processes. Lasering occurs at a distance of about 2 mm from the ciliary processes. From this distance one can usually see 6 ciliary processes in the field of view of the endoscope. This distance is ideal for minimizing laser energy transmission loss while also minimizing the risk of overtreatment. The power levels of the 810-nm semiconductor diode laser are titrated upward from lower power levels to achieve whitening and shrinkage of the ciliary processes. Usually 100-300 mW is all that is required to achieve the desired effect on tissues. A slow continuous wave application of the laser treatment allows surgeons to methodically “paint” the entirety of each ciliary process in a smooth, well-controlled fashion. Treatment of at least 270° is often required to get optimal intraocular pressure reduction with ECP. If administering ECP through one incision, the curved endoscope probe enhances a surgeon’s ability to expand the ciliary process treatment area beyond what can be accomplished with a straight endoscope. It has been shown that 360 degrees of treatment with ECP through two incisions is superior to partial treatment through one incision. 360 degree treatment produced lower IOP, gave greater reduction in glaucoma medication burden, and had fewer treatment failures than partial treatment.
For the most refractory cases, that have failed multiple glaucoma surgeries, ECP Plus can be performed. ECP Plus, is doing ECP but extending the treatment 1-2 mm onto pars plana for a more aggressive IOP lowering effect. This technique requires a pars plana approach and requires the patient to be pseudophakic or aphakic. A pars plana vitrectomy must also be performed.
CLICK HERE the watch a video of the ECP procedure.
The limited postoperative course following ECP is one of the most desirable features associated with the procedure. In most patients, postoperative management of both ECP alone and also combined ECP and cataract surgery is similar to that encountered with cataract surgery alone. The perioperative use of topical broad-spectrum antibiotic, topical prednisolone acetate 1% or topical difluprednate, and topical non-steroidal anti-inflammatory medication are generally recommended. A post-surgical injection of TriMoxi is a second effective option reducing the amount of post-operative medications required by the patient. In the immediate postoperative period, use of topical or systemic glaucoma medication may be helpful in preventing early postoperative intraocular pressure spikes. With early aggressive management of inflammation, complications such as posterior and anterior synechiae, posterior capsule opacification, and cystoid macular edema mirror those experienced in patients undergoing cataract surgery alone.
Glaucoma medications are often slowly tapered down over the first one to two months. After combined phaco-ECP numerous patients with mild glaucoma who were previously controlled on one to two drops have been completely tapered off their prior regimen with good IOP control.
IOP lowering from ECP is usually seen within the first postoperative month.
The most common risks for glaucoma patients undergoing cataract surgery with or without ECP include vision loss, excessive pain, hemorrhage, infection, inflammation, retinal detachment, blindness, retained lens material, zonular dehiscence, need for additional surgeries including trabeculectomy, failure of the procedure, posterior capsule opacification, ptosis, diplopia, and cystoid macular edema. The additional risks of glaucoma patients undergoing cataract surgery with the ECP procedure include hypotony, ciliary block glaucoma, and phthisis bulbi.
The ECP Collaborative Study Group reported their findings in 2007, of 5824 eyes with a mean follow up of 5.2 years. They reported IOP spikes in 14.5% of patients from retained viscoelastic, cataract in 24.5%, hyphema in 3.8%, and choroidal detachment in 0.36%. Cystoid macula edema rates were extremely low at 0.7% and vision loss > 2 lines were only seen in 1.03% of patients. Other serious complications such as retinal detachment occurred in 0.2%, choroidal hemorrhage in 0.09%, hypotony in 0.12%, and NLP vision in 0.12%. All of these severe complications occurred in eyes with neovascular glaucoma. No patients with POAG or PXG, PKP glaucoma, or ECP combined with phaco developed these issues. Also, no chronic inflammation or endophthalmitis was reported.