Superficial Keratectomy Technique Utilizing Femtosecond Spatula for Patients with Salzmann’s Nodular Degeneration
Title: Superficial Keratectomy Technique Utilizing Femtosecond Spatula for Patients with Salzmann’s Nodular Degeneration
Author: Vance Thompson, MD and Russell Swan, MD
Keywords/Main Subjects: Superficial keratectomy, SK, Salzmann’s Nodular Degeneration, SNG, Astigmatism
Diagnosis: Salzmann’s Nodular Degeneration, Astigmatism
Brief Description: This video demonstrates a surgical technique for Salzmann’s nodular degeneration (SND) that does not respond to conservative treatment. We utilize a femtosecond spatula to more easily identify a sub-nodular dissection plane to aid in efficient and safe removal of nodules. This technique has been utilized on 31 eyes of 19 patients with good success.
Salzmann’s nodular dystrophy (SND) is a non-inflammatory, progressive degeneration of the cornea which is normally characterized by multiple nodular blue-gray opacities. It was first described by Maximilian Salzmann in 1925.1 SND typically presents in people age 50-60, is bilateral in approximately 60% cases, and has a female preponderance of 70-80%.2,3 While many patients with SND may be asymptomatic, a proportion of patients will complain of irritation, watering, foreign body sensation and decreased vision.3 The nodules can induce refractive shifts including most often irregular astigmatism and a hyperopic shift.4 Patients with peripheral, small, non-visually significant nodules are often managed conservatively with medical treatment. This is often geared towards improving ocular surface homeostasis by improving tear volume, lid hygiene, and reducing inflammatory stimuli. In cases that do not respond to conservative treatment or in the case of visually significant nodules surgical management is often necessary. Most large case series report less than 10% of patients with SND will require surgical intervention.2,3,4 The most common procedure performed is a superficial keratectomy (SK). Adjuvant therapy include phototherapeutic keratectomy (PTK), amniotic membrane transplantation (AMT), or intraoperative mitomycin-C (MMC). This article describes a technique for superficial keratectomy utilizing a femtosecond spatula to assist in identifying the sub-nodular plane of dissection.
Description of Technique
The patient is prepped and draped in the usual fashion for ophthalmic surgery. The complete technique can be seen in the linked video. Often an irregular corneal light reflex will be noted secondary to the nodules (Figure 1A). The corneal epithelium is then removed at the anterior leading edge of the nodules (Figure 1B). A femto-second spatula is passed under the nodule to define the sub-nodular plane (Figure 1C). Once the plane is identified there will be minimal resistance to dissection. The spatula creates a dissection plane utilizing broad posterior to anterior sweeps. The posterior margin of the dissection can then be completed with either a blade or scissors.
Our preference is to treat these patients with adjuvant MMC to reduce risk of haze formation. In order to treat with MMC the remaining corneal epithelium is removed in the central 8.0 mm. A 8.0mm corneal well is utilized to treat the cornea with MMC 0.02% for 30 seconds (Figure 1D). The MMC is absorbed with surgical sponges and the ocular surface is rinsed aggressively. At the end of the case a bandage contact lens is placed on the eye. This is left in place until the cornea is completely epithelialized.
To date this technique utilizing the femtosecond spatula to assist in the dissection has been performed on 31 eyes of 19 patients between May 2013 and November 2016.
SND may cause visually significant hyperopia and astigmatism that may require surgical intervention. Many techniques have been described in the treatment of SND. These include but are not limited to SK2, SK with AMT5, SK with intraoperative MMC6, SK with PTK7, and SK with PTK and MMC6. One of the most important steps in SK for SND is to identify the sub-nodular plane of dissection. Traditionally this has been described by utilizing epithelial debridement to identify the edge and then forceps to remove the nodule. Some surgeons prefer use of a scalpel blade or diamond burr to help identify the leading edge.8 One of the challenges with these techniques is that in many cases it can be difficult to identify the plane of dissection. This is particularly true for smaller nodules. In addition, using a scalpel or other sharp dissection technique may risk creating an artificial dissection plane leading to incomplete removal of the nodule or too deep of a dissection resulting in a partial lamellar dissection. The benefit of utilizing a femtosecond spatula is that it is far less likely to create an artificial dissection plane and makes identification of the sub-nodular plane easier. The use of intraoperative topical MMC 0.02% for 30 seconds has been demonstrated to reduce hyperopia and scar formation6 and is the preferred technique at our center.
- Salzmann, M. About a variation of nodular dystrophy. Z. Augenheilkd. 1925; 57:92-9. German
- Graue-Hernandez, EO, Mannis, MJ, Eliasieh K, et al. Salzmann nodular degeneration. Cornea 2010; 29:283-9
- Farjo, AA, Halperin, GI, Syed N, et al. Salzmann’s nodular corneal degeneration clinical characteristics and surgical outcomes. Cornea. 2006; 25:11-5
- Das S, Link B. Salzmann’s nodular degeneration of the cornea: a review and case series. Cornea 2005; 24:772-7
- Rao A, Sridhar U, Gupta AK. Amniotic membrane transplant with superficial keratectomy in superficial corneal degenerations: efficacy in a rural population of north India. Indian J Ophthalmology 2008; 56:297-302
- Bowers Jr PJ, Price MO, Seldes, SS et al. Superficial keratectomy with mitomycin-C for the treatment of Salzmann’s nodules. J Cataract Refract Surg 2003; 29:1302-6
- Sharma N, Prakash G, Titiyal JS, et al. Comparison of automated lamellar keratoplasty and phototherapeutic keratectomy for Salzmann nodular degeneration. Eye Contact Lens 2012; 38:109-11