FP1295 : Loss of Frontalis Action After Unilateral Sling for Congenital Ptosis : a Cause for Undercorrection

Dr. Sujay Chauhan, C17713, Dr. Gupta Roshmi, Dr. Shetty Bhujang K

Authors: Sujay Chauhan, DO¹, Roshmi Gupta, MS¹, K. Bhujang Shetty, MS¹

Department of Ophthalmic Plastics, Orbital Disease and Ocular Oncology, Narayana Nethralaya, Bangalore, India 

Financial Support: None

 Proprietary Interest: Sujay Chauhan – None, Roshmi Gupta – None, K. Bhujang Shetty – None 

Running Head: Loss of Frontalis Action After Unilateral Sling 

Corresponding Author:Dr. Roshmi Gupta, MS

Ophthalmic Plastics, Orbital Disease and Ocular Oncology Service,

Narayana Nethralaya, 121/C, Chord Road, Rajajinagar 1^st R Block,

Bangalore 560010, India Phone: +91900768037

Email: roshmi.gupta@gmail.com

Loss of Frontalis Action After Unilateral Sling for Congenital Ptosis: A Cause for Undercorrection

 Introduction

There are multiple management options available for unilateral congenital ptosis including unilateral frontalis sling surgery¹, bilateral sling with or without unilateral disinsertion of levator², super-maximal levator advancement³ and Whitnall’s sling⁴. Unilateral frontalis sling surgery is an effective management option for patients with unilateral congenital ptosis as it bypasses the weak action of levator palpabrae superioris and r spares the normal eyelid from surgery. However, there are few limitations associated with this surgery including asymmetry between the lids, more so on down gaze, and lagophthalmos on the operated side. Another point of concern with this surgery is whether patients with frontalis overaction will continue to have it after surgery as the loss may lead to an under-correction of the ptosis. This study was undertaken to assess the outcome of unilateral silicone sling surgery in patients with severe congenital ptosis and its association with frontalis overaction.

Materials and Methods

This was a retrospective case series study of patients who underwent unilateral sling surgery for congenital ptosis between May 2014 and March 2016. Only patientswith complete pre- and ≥4 weeks’ post-operative clinical records (electronic medical record/photographs) including frontalisaction were included in the study. Pre- and post-operative analyses of ptosis and frontalis action were done by same observer for all patients. Criteria used to assess frontalis overaction included high forehead crease and arched eyebrow. All patents underwent sling surgery using silicone sling, supralash stab incision and Fox’s pentagon technique performed by a single oculoplastic surgeon. Under- or over-correction within 1 mm at final follow-up was considered as good outcome. Difference in palpebral fissure height >1 mm was considered unsatisfactory. Patients who had unequal palpebral fissure postoperatively, but recruited frontalis action on command to equalise, were also placed in the unsatisfactory outcome group.The study was approved by the Institutional Ethics Committee. The data was computed on a Microsoft Excel work sheet and the results were analyzed statistically using MedCalc^® software (version 12.5.0.0).

Results

The 33 study subjects comprised of 22 males and 11 females with a mean age of 15.45 ± 16.24 years (range 2 to 61 years) and 12.77 ± 10.17 years (range 9 months to 24 years) respectively. The mean ptosis at presentation was 4.65 ± 1.50 mm (range 3 to 9 mm). In all patients, the pupil was covered by the eyelid prior to surgery and unobstructed post-surgery. The average follow-up was 19.39 ± 23.22 weeks (range 4 to 104 weeks). Twenty-four patients had good correction at final follow-up and 9 were under-corrected.The mean residual ptosis was 0.76 ± 1.41 mm (range 1 mm overaction to 6 mm residual ptosis). No extrusion or slippage of sling was seen. Severity of ptosis (as defined by Margin Reflex Distance 1 ≤ 0) did not affect the final outcome (79.17% patients in well-corrected group and 77.77% in unsatisfactory group; Chi square test, p = 0.70). Of all well-corrected eyes, a third did not have frontalis overaction at presentation indicating that presence of frontalis overaction is not necessary for good cosmetic outcome.Presence of amblyopia also did not hamper equalising of the lid height (29.17% patients in well-corrected group and 22.22% in unsatisfactory group; Chi square test, p = 0.97). Out of 24 well-corrected patients, 15 patients had frontalis overaction which was maintained in 12 patients post-operatively. All 9 under-corrected patients presented with frontalis overaction preoperatively, which waslostafter surgery. Thisassociation between surgical outcome and loss of frontalis overaction after surgery was statistically significant (Chi square test, p = 0.0007). There was no significantly high rate of lagophthalmos in well-corrected group as compared to unsatisfactory group (37.50% and 22.22% respectively; Chi square test, p = 0.45).

Conclusion

There were few limitations of this study. Being a retrospective study, many patients did not have specific mention of frontalis overaction in the medical record and only 33 patients could be studied out of 68 operated. In addition, there is possibility of bias where clinician would have recorded the poor frontalis action in particular when post-operative cosmesis was less than desired and missed where the outcome was good. Patients with poor frontalis action were more likely to be adjusted with a tighter sling to obtain a higher eyelid level intraoperatively.

Silicone frontalis sling is an easy (average surgical duration of 12 minutes), safe and effective surgical option for congenital ptosis where the aim is to prevent amblyopia. Patients with congenital ptosis are often found to have overaction of frontalis muscle in an attempt to clear the visual axis. Unilateral sling provides good to excellent functional and cosmetic results in these cases. However, in some cases, there occurs loss of frontalis overaction after surgery accounting for under-correction. It is hypothesized that the uncovering of visual axis by resetting the lid heightprobably eliminates the stimulus for use of frontalis. Hence, for cosmesis, other options which are less dependent on frontalis action can be considered such as a rigid material like fascia lata for sling, deliberate higher placement of lid height intraoperatively and supramaximal LPS resection.

References

1. Kersten R et al. Unilateral frontalis sling for the surgical correction of unilateral poor-function ptosis. Ophthal Plast Reconstr Surg 2005;21(6):412-417.
2. Beard C. A new treatment for severe unilateral congenital ptosis and for ptosis with jaw-winking. Am J Ophthalmol 1965 Feb;59:252-258.
3. Epstein G and Putterman A. Supermaximum levator resection for severe unilateral congenital ptosis. Ophthalmic Surg 1984;15(12):971-979.
4. Anderson R et al. Whitnall’s sling for poor function ptosis. Arch Ophthalmol 1990;108:1628-1632.