Transmuscular migration of solid silicone band

The article ‘Transmuscular migration of 240 silicone encircling band’ by Kreis et al1 has prompted us to share our experience with a similar case.

We recently reviewed a 71-year-old man who presented with an 8-week history of horizontal binocular diplopia after bumping his head against a lamppost. Past ocular history included left

retinal detachment surgery in 1999 with MIRA 276 and 240 silicone bands without post-operative diplopia at discharge. Visual acuities were 6/6 OD, 6/36 OS. There was limitation of abduction

in the left eye and a left esotropia worse for distance than for near, mimicking sixth nerve palsy. Slit lamp examination revealed several eyelashes embedded beneath the conjunctiva, drawing

attention to an area of conjunctival erosion superotemporally (Figure 1), where the silicone band and anchoring suture were found to be exposed (Figure 2). During surgery for removal of the

silicone band, the lateral rectus was not recognized at its insertion. Although repositioning of the muscle was not attempted, his diplopia improved postoperatively and was successfully

treated with prisms.

Several eyelashes embedded in the conjunctiva drawing attention to area of erosion superotemporally.

Exposed buckle and anchoring suture. (Reproduced from Eye News 2007, in press. Courtesy of Pinpoint Scotland Ltd.).

This suggested a possible element of mechanical restriction contributing to the diplopia, as a bulky explant beneath the tendon of the medial rectus can effectively shorten the muscle,

limiting its ability to stretch.2

Diplopia with ocular motility disturbances as a result of migrating buckling elements through the recti muscles has been well documented,3, 4, 5 including those requiring surgical

repositioning of the transected tendon.3 Ocular motility disturbances did not occur as one might expect in several cases4, 5 that were thought to be unique, in that reattachment of the

muscle fibres or sheath relatively closely behind the migrating element possibly allowed preservation of recti function.4 Lanigan,5 in a series of five patients, reported two with ocular

motility disturbances and cautioned that a larger series is needed before one can comment on the true incidence of ocular motility dysfunction following this complication. Therefore, it may

be misleading to conclude that ‘the migrating encircling band is not usually linked to ocular motility disturbance’. We suggest that it is important to consider migration of encircling

elements in the differential diagnosis of diplopia in patients with previous scleral buckling procedures to ensure that important clinical signs are not overlooked in examination.

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