Clinical features of Helveston syndrome and discussion of individualized surgical design.

Background: Reasonable personalized surgical design can achieve good treatment results for Helveston syndrome in one surgery, reducing the psychological and economic burden on patients. This article aims to explore the clinical characteristics of Helveston syndrome and the clinical effectiveness and feasibility of individualized surgical design.

Methods: In this retrospective case series study, 28 patients who underwent strabismus correction for Helveston syndrome at the Affiliated Hospital of Yunnan University from June 2018 to December 2020 with complete follow-up data were enrolled. Preoperatively, all patients received standard assessment of vision, intraocular pressure, slit lamp, fundus and refractive status, excluding other eye diseases, as well as detailed special examination of strabismus. These patients were divided into two groups according to the surgical modality: the horizontal muscle surgery alone group and the horizontal muscle surgery combined with superior oblique muscle surgery (combined surgery) group. We used SPSS software for data analysis and compared the postoperative eye position, eye movement, success rate, and reoperation rate between these two groups. Clinical measurement data were compared and analyzed with Fisher's exact test for count data, the -test for normally distributed measurement data, and the Mann-Whitney test for non-normally distributed measurement data. P<0.05 was considered statistically significant.

Results: This study included a total of 28 patients with Helveston syndrome, including 20 males and 8 females. The average age at the time of surgery is 12.04 ± 8.67 years (range, 4-43 years). The postoperative A-pattern degree was significantly greater in the group undergoing horizontal muscle surgery alone [6.23±1.31 prism diopters (PD); range, 0-10 PD] than in the group undergoing combined surgery (0.53±0.32 PD; range, 0-4 PD; P=0.002). Superior oblique muscle overactivity was significantly reduced in the combined surgery group (0.20±0.11+; range, 0-1+) compared to the horizontal muscle surgery alone group (1.31±0.26+; range, 0-2+; P=0.002). However, there was no significant difference in success rate or reoperation rate between the two groups. Additionally, after combining the recession of the superior rectus muscle with the horizontal muscle, the number of A-pattern degrees was greatly reduced.

Conclusions: Helveston syndrome can be improved using a personalized surgical design according to the degree of external strabismus A-pattern, superior oblique muscle overaction, and dissociated vertical deviation (DVD) degree, which improves the success rate of single surgery.