Sling for the sling: a new technique for long-term correction of severe congenital ptosis

Congenital ptosis is a condition characterized by the drooping of one or both upper eyelids present at birth or within the first year of life which results in a narrow vertical palpebral fissure. It occurs due to the inadequate development of the levator palpebrae superioris (LPS) muscle [1]. Severe congenital ptosis can result in visual impairment and complications such as amblyopia, astigmatism, and ocular torticollis, which can necessitate early surgical intervention to preserve visual function [2].

The type of surgery performed depends upon levator function and ptosis severity. Tarsofrontalis sling is reserved for those with poor levator function (i.e. upper eyelid excursion less than 4 mm); it involves tethering the tarsal plate to the frontalis muscle with a ‘sling’ so that the brow and forehead movement are responsible for eyelid movement, bypassing the malfunctioning LPS [3].

Frontalis sling procedure is generally considered safe and effective, however the risk of lagophthalmos is significant in certain vulnerable patients namely those with poor Bell’s phenomenon, ocular myasthenia gravis, congenital fibrosis of extraocular muscles and other muscular dystrophies. Autogenous Fascia lata graft is commonly used as a sling for the surgery. However, harvesting the fascia lata requires an added surgical site, carrying the risk of possible donor site complications such as pain, impaired gait and persistent scarring [4]. Moreover, it is not recommended in children under 4 years of age limiting its wide use. All these concerns have led surgeons to seek alternative synthetic materials, including nonabsorbable suture materials (nylon, polypropylene, polyester), polytetrafluoroethylene and silicone rods [5]. Silicone possesses great elasticity which facilitates smooth and effective blinking motion, thus theoretically reducing risk of corneal complications. It also offers convenient adjustability in the event of any necessary revisions and allows for straightforward removal of the sling at a later date if deemed necessary. However, recurrence after silicone rods sling constituted a potential threat to long term patient satisfaction [3].

In this comparative study, we compare the outcomes of two surgical techniques of tarsofrontalis sling surgery– with and without the use of green braided polyester (Ethibond) sutures to fix the silicon rods in severe congenital ptosis patients.

This study was a retrospective single-centre analysis of patients with severe congenital ptosis who underwent surgical correction using two different techniques: the traditional Silicon rods ptosis sling and the novel technique using Silicon rods with Ethibond sutures for fixation. The study was conducted at the department of ophthalmology, faculty of medicine, Zagazig university, Zagazig, Egypt.

We reviewed the medical records of patients operated by both techniques in the period between December 2020 and December 2021. Criteria for participant selection were the following: confirmed diagnosis with unilateral or bilateral severe congenital ptosis with poor levator function (i.e., upper eyelid excursion is less than 4 mm), age below 12 years, no previous history of ptosis or any other eyelid surgeries, good Bell’s phenomenon and recorded completion of 18 months postoperative follow up. Patients with ocular myasthenia, poor Bell’s phenomenon, Marcus Gunn jaw winking and corneal hyposthesia were excluded from the study. The parents of all the participants provided an informed consent for their children to undergo the surgical procedures. The study was approved by the institutional review board of the faculty of medicine, Zagazig university, and the entire study protocol adhered to the principles outlined in the Declaration of Helsinki of 1964, as revised in 2013.

Data collected from patients’ records included demographic information, preoperative and postoperative marginal reflex distance (MRD1), levator function, follow up duration as well as postoperative complications.

A total of 60 eyelids of 34 patients were included in this study and according to the technique used for fixation of silicone rod sling, two groups of patients were identified. Group I which consisted of 35 eyelids of 20 patients operated with the traditional technique of silicone rod fixation using the sleeve only (15 bilateral, 5 unilateral), while group II included 25 eyelids of 14 patients who had received the new “sling for sling” technique (11 bilateral, 3 unilateral). The mean age of patients was 5 years (median 4.5; range 1–12 years). Both groups were comparable for baseline characteristics including age, gender, laterality, levator function and follow-up. Table 1 shows the baseline demographic data for both groups.

Table 2 shows the preoperative MRD 1 and the final MRD1 measured at the last follow up visit in each group. Both groups show a significant increase in the postoperative MRD1 when compared to the preoperative MRD1. The postoperative MRD1 started to differ between both groups over the different follow up visits. By the last follow up visit; this difference showed a statistical significance (p = 0.04*) with a higher mean value in the sling for sling group.

Table 3 shows the postoperative complications recorded in both groups with statistically higher recurrence rate in the first group (p < 0.001*) while no detectable statistically significant difference existed regarding wound-related complications (p = 0.7). They included wound dehiscence, suture granuloma, or rod migration. Complications were managed effectively with conservative measures in most of the cases except for 2 patients (one in each group) who required sling removal due to its prolapse through the superior central incision.

Figure 3 shows the preoperative (A), the early postoperative (1 month) (B) and the final postoperative (18 months) (C) appearance of a patient belonging to the first group with moderate recurrence of ptosis. While Fig. 4 shows the preoperative (A), the early postoperative (1 month) (B) and the late postoperative (18 months) (C) of a patient belonging to the second group showing the sustainability of the sling effect on application of the Ethibond sling fixation. The outcome of both groups as recorded in the last follow up visit is illustrated in Fig. 5 with statistically significant differences (p < 0.001).

The management of severe congenital ptosis remains a complex and challenging task for oculoplastic surgeons, necessitating innovative surgical approaches for optimal outcomes. In this study, we conducted a comparative analysis of two distinct surgical techniques employed in the treatment of severe congenital ptosis: the traditional Silicon rods ptosis sling and a novel technique involving the use of Silicon rods with Ethibond sutures for fixation.

Our findings revealed that both the traditional Silicon rods ptosis sling and the novel technique using Silicon rods with Ethibond sutures were effective in achieving significant improvements in eyelid height and function among patients with severe congenital ptosis. These results are consistent with previous studies that have demonstrated the efficacy of the Silicon rods ptosis sling in correcting severe ptosis [6, 7, 8, 9]. The traditional technique’s reliability and consistent outcomes have made it a widely adopted approach for severe congenital ptosis.

However, the novel technique utilizing Silicon rods with Ethibond sutures introduces an innovative and promising approach to increase the durability of the correction. A significantly less incidence of recurrence was noticed in the second group that could be explained by the effect of the Ethibond suture which fixes the silicone rod to the frontalis muscle for a longer duration allowing more time for fibrosis to occur along the track of the sling material before losing its tensile stress and preventing its cheese-wiring into the muscular and subcutaneous tissue which are considered the main factors responsible for recurrence [10, 11].

The post-operative complications were evaluated within two groups. Group I (n = 23) displayed granulomas in 5.7% of cases, with no instances of infection. Conversely, a solitary case (2.8%) of extrusion was noted. The cumulative ensemble of wound-related complications was quantified at 8.5%. This rate is comparable to the rate encountered by Morris et al. (9%) [12] but higher than that reported by both Buttanri et al. [13] and Ben Simon et al. [14] who found no wound related complications when used silicone as a sling material.

In Group II (n = 25), granulomas and infections were noted in 4% of cases each and no cases of extrusion were noticed. The wound-related complications in Group II culminated at 8%, subtly mirroring Group I’s narrative. This rate agrees with the wound related complications rate reported by Wasserman et al. [15] (9.1%) and Bajaj et al. [16] (13%) who used Ethibond suture alone to perform the frontalis sling surgery.

Unexpectedly, we didn’t find a significant increase in the wound related complications in the ”sling for sling” group when Ethibond was added to silicone tube. This can be attributed to meticulous technique execution, including secure and robust fixation of the suture and sleeve to the underlying tissue, as well as the employment of a layered wound closure approach. These factors collectively contribute to the overall success and safety of using the silicon rods with Ethibond sutures for fixation technique.

Regarding the recurrence of complications, Group I displayed a recurrence rate of 23%, with a mean time of recurrence measured at 16 ± 3.5 months.This rate is similar to that reported by other studies using silicone alone e.g.Lee et al. [17] (29%) and Buttanri et al. [13] (23.75%).

In contrast, Group II exhibited a lower recurrence rate of 8%, with a mean time of recurrence recorded at 12.3 ± 2.5 months. The statistical analysis for recurrence rates demonstrated a highly significant p-value of less than 0.001, highlighting a substantial discrepancy in recurrence patterns between the two groups. This rate of recurrence is much lower than that reported by other studies that used other sling materials namely Ethibond suture as Bajaj et al. [16] (17%), Nylon suture as Hayashi et al. [18] (62%), fascia lata strip as Ben Simon et al. [14] (22%) or silicone tube alone as mentioned earlier. It is highly comparable to the low recurrence rate found when using autologous fascia lata [19, 20].

Tables S1 and S2 present the preoperative and postoperative characteristics, along with complications, for the traditional technique and the sling for sling surgical approach, respectively.

Despite the promising results, it is essential to consider the limitations of our study. The relatively small sample size and short-term follow-up limit the generalizability of the findings. Larger-scale, long-term studies with extended follow-up periods are necessary to validate the outcomes and assess the long-term stability and safety of the novel technique.

Both the traditional Silicon rods ptosis sling and the novel technique using Silicon rods with Ethibond sutures offer viable surgical options for managing severe congenital ptosis. The traditional technique has a proven track record of reliability, while the novel approach introduces long term corrective effect with no associated increase in wound related complications. Further research with larger cohorts and longer follow-up periods is warranted to confirm these findings.