Surgery and botulinum toxin in congenital esotropia

A Comparison of Chemodnervation to Incisional Surgery for Acute, Acquired, Comitant Esotropia: An International Study

PURPOSE

To compare the efficacy of botulinum toxin injections to strabismus surgery in children with acute, acquired, comitant esotropia (ACE), and to investigate factors predicting success.

DESIGN

International, multi-center nonrandomized comparative study METHODS: Setting: Cloud-based survey.

STUDY POPULATION

Children aged 2 to 17 years who underwent a single surgical intervention for ACE.

INTERVENTIONS

Botulinum toxin injection ("chemodenervation" group) or strabismus surgery ("surgery" group).

MAIN OUTCOME MEASURES

Primary measure: success rate at 6 months in propensity-matched cohort, defined as total horizontal deviation of 10 prism diopters or less with evidence of binocular single vision. Secondary measure: Risk factors for poor outcomes in the full cohort.

RESULTS

Surgeons from 19 centers contributed. There were 74 patients in the chemodenervation group and 97 patients in the surgery group. In the propensity-matched data (n = 98), success rate was not significantly different at 6 months (70.2% vs 79.6%; P = .2) and 12 months (62.9% vs 77.8%; P = .2), but was significantly lower in the chemodenervation group at 24 months (52% vs 86.4%; P = .015). Irrespective of treatment modality, treatment delay was associated with lower success rates at 6 months, with median time from onset to intervention 4.5 months (interquartile range (IQR): 2.1, 6.7) in the success group and 7.7 months (IQR: 5.6, 10.1) in the failure group (P < .001).

CONCLUSIONS

In children with ACE, success rate after chemodenervation was similar to that of surgery for up to 12 months but lower at 24 months. Those with prompt intervention and no amblyopia had the most favorable outcomes, regardless of treatment modality.

Interventions for infantile esotropia

BACKGROUND

Infantile esotropia (IE) is the inward deviation of the eye. Various aspects of the clinical management of IE are unclear; mainly, the most effective type of intervention and the age at intervention.

OBJECTIVES

To examine the effectiveness and optimal timing of surgical and non-surgical treatment options for IE to improve ocular alignment and achieve or allow the development of binocular single vision.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, one other database, and three trials registers (November 2021). We did not use any date or language restrictions in the electronic searches for trials.  SELECTION CRITERIA: We included randomized trials and quasi-randomized trials comparing any surgical or non-surgical intervention for IE.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology and graded the certainty of the body of evidence for six outcomes using the GRADE classification.

MAIN RESULTS

We included two studies with 234 children with IE. The first study enrolled 110 children (mean age 26.9 ± 14.5 months) with an onset of esotropia before six months of age, and large-angle IE defined as esotropia of ≥ 40 prism diopters. It was conducted between 2015 and 2018 in a tertiary care hospital in South Africa. It compared a maximum of three botulinum toxin injections with surgical intervention of bimedial rectus muscle recession, and children were followed for six months. There were limitations in study design and implementation; the risk of bias was high, or we had some concerns for most domains.  Surgery may increase the incidence of treatment success, defined as orthophoria or residual esotropia of ≤ 10 prism diopters, compared with botulinum toxin injections, but the evidence was very uncertain (risk ratio (RR) of treatment success 1.88, 95% confidence interval (CI) 1.27 to 2.77; 1 study, 101 participants; very low-certainty evidence). The results should be read with caution because 23 children with > 60 prism diopters at baseline in the surgery arm also received botulinum toxin at the time of surgery to augment the recessions. There was no evidence of an important difference between surgery and botulinum toxin injections for over-correction (> 10 prism diopters) of deviation (RR 0.29, 95% CI 0.06 to 1.37; 1 study, 101 participants; very low-certainty evidence), or additional interventions required (RR 0.66, 95% CI 0.36 to 1.19; 1 study, 101 participants; very low-certainty evidence). No major complications of surgery were observed in the surgery arm, while children experienced various complications in the botulinum toxin arm, including partial transient ptosis in 9 (16.7%) children, transient vertical deviation in 3 (5.6%) children, and consecutive exotropia in 13 (24.1%) children. No other outcome data for our prespecified outcomes were reported.  The second study enrolled 124 children with onset of esotropia before one year of age in 12 university hospitals in Germany and the Netherlands. It compared bilateral recession with unilateral recession surgeries, and followed children for three months postoperatively. Very low-certainty evidence suggested that there was no evidence of an important difference between bilateral and unilateral surgeries in the presence of binocular vision (numbers with event unclear, P = 0.35), and over-correction (RR of having exotropia 1.09, 95% CI 0.45 to 2.63; 1 study, 118 participants). Dissociated vertical deviation, latent nystagmus, or both were observed in 8% to 21% of participants.

AUTHORS' CONCLUSIONS

Medial rectus recessions may increase the incidence of treatment success compared with botulinum toxin injections alone, but the evidence was very uncertain. No evidence of important difference was found between bilateral surgery and unilateral surgery.  Due to insufficient evidence, it was not possible to resolve the controversies regarding type of surgery, non-surgical intervention, or age of intervention in this review. There is clearly a need to conduct good quality trials in these areas to improve the evidence base for the management of IE.

[Long term outcomes of botulinum toxin injections in infantile esotropia]

PURPOSE

To evaluate long terms outcomes of botulinum toxin in infantile esotropia by measuring the amount of microtropia 24 months after injection. Secondary purpose was to identify predictive factors of microtropia.

METHODS

A retrospective, single-center study was performed at the university medical center in Bordeaux between 2001 and 2018, including all patients with infantile esotropia greater than 20 D. All patients received 5 or 7,5 IU of botulinum toxin A in each medial rectus, once or twice depending on the angle of deviation after the first injection and after wearing full optical correction at least two months. We noted the angle at 1, 6, 12 and 24 months, the occurrence of any complications and the need for later strabismus surgery. The primary endpoint was the achievement of a microtropia less than 8 diopters (D) at 24 months post-injection. We evaluated the predictive factors for microtropia with a Fischer's test.

RESULTS

We included 30 patients with esotropia greater than 20 D. The mean follow-up after injection was 48 months ±30. The mean age was 16.24 months (7-29 months) with a female predominance in the population (SR=0.43). The mean pre-injection deviation was 41.25±12.17 D. The majority of patients were mildly (40%) or moderately (40%) hyperopic. At 24 months, 46.7% microtropias were obtained (95% CI: 28.9%-64.5%). The change in mean angle at 1, 6, 12 and 24 months post-injection was -8.57±25.21 D; 14.48±13.40 D; 18.38±12.07 D and 21.23±14.97 D, respectively. No factors were predictive of microtropia. Of the 30 children, 3 had transient ptosis requiring strips and 12 showed an exotropia at 1 month. All complications were self-limited and without consequences. 3 children had a second injection of botulinum toxin, which in 2/3 of the cases resulted in a long-lasting microtropia. 26.7% (n=8) of the children underwent secondary surgery. Obtaining a microtropia 24 months after injection statistically significantly reduced the need for secondary strabismus surgery: 92.9% P=0.039% CI 95% (0.002; 1.0606).

CONCLUSION

Botulinum toxin appears to be a less invasive and more conservative alternative to surgery in children with infantile esotropia. In 46.7% of cases, microtropia is achieved. An improvement was noted in 90% (n=27) of the children with a reduction of half (21.23 D) of the mean post-injection angle at 24 months. When effective, it significantly reduces the need for secondary surgery.

The Use of Botulinum Toxin in Strabismus Treatment

There is a long and extensive experience with the use of Botulinum Toxin type A (BoNT-A) injection in the treatment of different types of strabismus and oculomotor palsies. The frequency of its use varies depending on the country and institution. It is a short procedure, may reduce general anesthesia exposure, causes minimal scarring compared to surgery, and can be proposed as an early treatment in unstable strabismus. Over many years, the experience of using BoNT-A indications has been refined and new applications have been reported. The use of BoNT-A in the postoperative period, after strabismus surgery or during surgery, can also be beneficial.

Comparative Study of Y-Split Recession versus Faden Technique for Management of Infantile Esotropia in Egyptians

Purpose

This study compares the results of Y-split recession versus de Decker's (modified Cüppers) Faden techniques of medial rectus (MR) muscles for the management of essential infantile esotropia (IET).

Patients and Methods

Fifty patients had IET divided into Group A who underwent Y-split recession of MR muscles and Group B who underwent de Decker's Faden technique of MR muscles. All patients had complete ophthalmic examination done including deviation angle measurement and met the inclusion criteria of the study. Operations were performed using general anesthesia. Patients were followed up at day 1, week 1, and months 1, 3, and 6 after operation.

Results

The mean age distribution for group A was 21.56 months (SD 12.55) and for group B was 21.4 months (SD 12.35), and the mean postoperative follow-up interval was 6 months for both groups. The preoperative maximum angle of deviation in both groups ranged from 15 to 40 degrees, while the minimum angle of deviation ranged from 10 to 20 degrees. Immediately postoperatively both groups showed 88% of patients with satisfactory results (within 10 degrees of orthotropia). Group A showed two patients (8%) with ET and one patient (4%) with exotropia (XT). For group B, it showed one patient (4%) with ET and two patients (8%) with XT. Three patients in each group underwent a second intervention. All patients remained within the satisfactory range.

Conclusion

The results of this study suggest that both techniques show comparable results for the correction of IET.

Comparative study of Y-split recession versus bilateral medial rectus recession for surgical management of infantile esotropia

Aim

This prospective study compares the results of bilateral medial rectus recession versus (vs) Y-split recession of medial recti techniques for surgical management of essential infantile esotropia.

Patients and methods

Thirty patients were included in this study and had preoperative infantile esotropia with large angles (ie, >30 prism diopters [PD]). Patients were divided into Group A, which underwent bilateral medial rectus (BMR) recession and Group B, which underwent bilateral Y-split recession of medial recti muscles. All patients were subjected to complete ophthalmologic examination and met the criteria for inclusion in this study. The degrees of BMR recessions performed ranged from 6.0–7.5 mm. All operations were performed under general anesthesia. Follow-up visits were conducted at 1 and 2 weeks, and 1, 3, and 6 months postoperatively. Rates of reoperation for residual esotropia and consecutive exotropia were determined.

Results

The patients’ preoperative angles of deviation ranged from 30–80 PD. Group A consumed 57% less operative time than Group B. Immediately postoperatively, the Y-splitting technique showed satisfactory results (ie, orthotropic or residual angles ≤15 PD) in 73% of patients vs 67% only for the BMR recession patients. By the end of six months of follow up; 13% of the BMR technique patients vs 27% of the Y-splitting technique patients showed negative change of PD but without reoperation.

Conclusion

Our results suggest that, although the Y-splitting technique is more difficult and time consuming, both procedures are effective and have shown comparable results for the correction of horizontal deviation ≤70 PD.

Interventions for infantile esotropia

BACKGROUND

Infantile esotropia (IE) is the inward deviation of the eye. Various aspects of the clinical management of IE are unclear; mainly, the most effective type of intervention and the age at intervention.

OBJECTIVES

The objective of this review was to assess the effectiveness of various surgical and non-surgical interventions for IE and to determine the significance of age at treatment with respect to outcome.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 5), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE, (January 1950 to June 2013), EMBASE (January 1980 to June 2013), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to June 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 10 June 2013. We manually searched the conference proceedings of the European Strabismological Association (ESA) (1975 to 1997, 1999 to 2002), International Strabismological Association (ISA) (1994) and American Academy of Paediatric Ophthalmology and Strabismus meeting (AAPOS) (1995 to 2003). Efforts were made to contact researchers who are active in the field for information about further published or unpublished studies.

SELECTION CRITERIA

We included randomised trials comparing any surgical or non-surgical intervention for infantile esotropia.

DATA COLLECTION AND ANALYSIS

Each review author independently assessed study abstracts identified from the electronic and manual searches.

MAIN RESULTS

No studies were found that met our selection criteria and therefore none were included for analysis.

AUTHORS' CONCLUSIONS

The main body of literature on interventions for IE are either retrospective studies or prospective cohort studies. It has not been possible through this review to resolve the controversies regarding type of surgery, non-surgical intervention and age of intervention. There is clearly a need for good quality trials to be conducted in these areas to improve the evidence base for the management of IE.

Sustained release of bone morphogenetic protein-4 in adult rabbit extraocular muscle results in decreased force and muscle size: potential for strabismus treatment

Purpose. To assess the effect of a sustained-release preparation of bone morphogenetic protein-4 (BMP-4) on EOM force generation and muscle size. Methods. Sustained-release pellets, releasing 500 nanograms/day of BMP-4 for a maximum of 3 months, were implanted beneath the superior rectus muscle (SR) belly in anesthetized adult rabbits. The contralateral side received a placebo pellet as a control. After 1, 3, and 6 months, SRs were removed, and force generation at twitch and tetanic frequencies as well as fatigue resistance were determined in vitro. Myofiber size, myosin heavy chain isoform expression, and satellite cell density were assessed histologically. Results. SR force generation was significantly decreased by BMP-4 compared with the contralateral controls. Force generation was decreased by 25-30% by 1 month, 31-50% by 3 months, and at 6 months, after 3 BMP-4-free months, force was still decreased by 20-31%. No change in fatigue was seen. Significant decreases in muscle size were seen, greatest at 3 months. At all time points Pax7- and MyoD-positive satellite cell densities were significantly decreased. Conclusions. The decreased force generation and muscle size caused by sustained release of BMP-4 suggests that myogenic signaling factors may provide a more biological method of decreasing muscle strength in vivo than exogenously administered toxins. Treating antagonist-agonist pairs of EOM with titratable, naturally occurring myogenic signaling and growth factors may provide safe, efficacious, nonsurgical treatment options for patients with strabismus.

The effect of the Botulinum toxin-A on craniofacial development: an experimental study

In this study, we developed a novel experimental model to evaluate muscular action on bone formation and remodeling by the help of Botulinum toxin-A (BTX). Forty-nine 15-day-old male Wistar rats were put into 4 groups randomly. Group 1 was the control group. BTX 0.4 IU (0.05 mL) was injected into the right masseter muscle in group 2 and into right temporalis muscle in group 3. The same volume of sterile saline was given into the both above-mentioned muscles in group 4. At the end of the fourth month, all animals were killed. Histology and weight of the masseter and temporalis muscles were studied. Thirty different osteometric measurements were also taken from skulls. Significant atrophy in BTX injected muscles was observed in groups 2 and 3. In group 4 (saline injection), only few osteometric measurements were significantly reduced, indicating the effect of the injection itself. Both groups 2 and 3 have apparent decrease in nasal bone, premaxilla, maxilla, and zygomatic dimensions on the injected side. When masseter group was compared with control and saline groups, no significant difference was found in skull base dimensions and mandibular length. In contrast, temporal group has also shown significant decrease in skull base dimensions. Our conclusions are as follows: (1) With this model, it is possible to study muscular action on bone formation and modeling without any surgical intervention, that is, by avoiding surgical artifacts, such as scar and contracture; (2) denervation of the skeletal muscles with BTX during the growing phase does effect bone development in a negative way; (3) pediatric use of the BTX deserves reevaluation under the light of these findings.

A comparison of two different techniques for oculomotor torque reduction

PURPOSE

To compare the results of two different surgical techniques: 'Cüppers technique', in which the torque of oculomotor rectus muscles is reduced by suturing the muscle to the globe in the posterior half of the globe; and 'Y-split recessions', in which the muscle torque is reduced by Y-splitting the rectus muscles, and reattaching the two halves at an angle to each other.

METHODS

We carried out a retrospective analysis of the outcome of surgery on 100 patients with infantile esotropia.

RESULTS

Both techniques show a sufficient reduction of strabismus angle variability, and minimal and maximal strabismus angle.

CONCLUSIONS

Both techniques achieve satisfactory results. In addition, the Y-split technique allows for accurate control of the muscle torque and requires no access to the posterior half of the eye, which can facilitate the surgical approach. For a reduction in muscle torque, the Y-split recession is a good alternative to the established Cüppers technique.

Use of botulinum toxin in strabismus

PURPOSE OF REVIEW

The history, pharmacology, indications, complications, and success rates of botulinum administration are discussed in this review as they relate to strabismus and associated conditions.

RECENT FINDINGS

Botulinum has been used to treat strabismus and a variety of other ocular conditions for over three decades. Alan Scott initially investigated extraocular muscle paralysis by botulinum injection in 1973, and in the ensuing years botulinum has been evaluated as a treatment for horizontal and vertical strabismus, nystagmus, dissociated vertical deviation, sensory strabismus, ophthalmoplegia, and paradoxical diplopia.

SUMMARY

Botulinum administration is a strabismus treatment option that may be considered for some strabismus patients; in select cases botulinum is a reasonable and preferable alternative to surgery. Current clinical recommendations regarding botulinum should be considered in the context of the existing comparative studies that are summarized in this review. Since there are very limited data directly comparing the success rates of botulinum with standard strabismus surgery, additional, well designed prospective studies are needed. Data from such studies would enable recommendations for strabismus management to be formulated using an evidence-based approach.

Interventions for infantile esotropia

BACKGROUND

Various aspects of the clinical management of infantile esotropia (IE) are unclear - mainly, the most effective type of intervention and the age at intervention.

OBJECTIVES

The objective of this review was to assess the effectiveness of various surgical and non-surgical interventions for IE and to determine the significance of age at treatment with respect to outcome.

SEARCH STRATEGY

Trials were identified from the Cochrane Central Register of Controlled Trials - CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) in The Cochrane Library (Issue 3 2004), MEDLINE (1966 to July 2004), EMBASE (1980 to August 2004) and LILACS (July 2004). We manually searched the conference proceedings of the European Strabismological Association (ESA) (1975-1997, 1999-2002), International Strabismological Association (ISA) (1994) and American Academy of Paediatric Ophthalmology and Strabismus meeting (AAPOS) (1995-2003). Efforts were made to contact researchers who are active in the field for information about further published or unpublished studies.

SELECTION CRITERIA

Randomised trials comparing any surgical or non-surgical intervention for infantile esotropia.

DATA COLLECTION AND ANALYSIS

Each reviewer independently assessed study abstracts identified from the electronic and manual searches.

MAIN RESULTS

No studies were found that met our selection criteria and therefore none were included for analysis.

AUTHORS' CONCLUSIONS

The main body of literature on interventions for IE are either retrospective studies or prospective cohort studies. It has not been possible through this review to resolve the controversies regarding type of surgery, non-surgical intervention and age of intervention. There is clearly a need for good quality trials to be conducted in these areas to improve the evidence base for the management of IE.