Surgical management of Helveston syndrome (triad of A- pattern exotropia, superior oblique overaction and dissociated vertical deviation) using 'Four Oblique' procedure

Abstract

Purpose: To report the surgical outcomes in six patients of Helveston syndrome using a “four oblique” procedure. The popular methods for surgical management include superior rectus recessions alone or combined with superior oblique tenectomy. However, large angle exotropia correction would entail a higher risk of anterior segment ischemia when the superior rectus needs to be operated along with the horizontal recti. Hence, we evaluated the long-term results of this uncommon procedure. Methods: This was a retrospective review of six patients diagnosed to have manifest dissociated vertical deviation (DVD) with A pattern exotropia with bilateral superior oblique over action. All patients underwent horizontal muscle recessions/resections for exotropia along with bilateral posterior tenectomy of the superior oblique with inferior oblique anterior transpositioning. Results: The median age was 10 years (Range 5–26 years). The mean postoperative follow-up was 26 ± 14.02 months (Range 12–48 months). The mean reduction in exotropia was from 36.5 ± 21.06 PD (Range 15–65 PD) to 6.1 ± 3.06 PD (Range 3–10 PD). The procedure corrected the A pattern from a mean 23 ± 7 PD (Range 15–35 PD) to 7.6 ± 3.2 PD (Range 3–10 PD). The average DVD in the right eye reduced from 14 ± 4.3 PD (Range 8–20 PD) to 5.3 ± 1.2 PD and in the left eye from 14.33 ± 3.6 PD (Range 10–18 PD) to 4.1 ± 1.1 PD. The DVD asymmetry reduced from 6.33 ± 3.4 PD to 1.5 ± 1.3 PD. Conclusion:”Four oblique” procedure with horizontal muscle surgery seems to be an effective method for significantly correcting the A pattern as well as reducing the DVD with good long-term outcome in our case series.

Keywords

• a-pattern exotropia
• dissociated vertical deviation
• inferior oblique anteropositioning
• superior oblique over action
• superior oblique tenectomy