Pediatric and Adult Strabismus Surgery

Pediatric and Adult Strabismus Surgery

Strabismus surgery is the most commonly performed ophthalmic procedure in children. This type of surgery is also performed on adults with new or previously existing ocular misalignment. Recession and resection procedures are typically performed for horizontal misalignment (esotropia and exotropia); other approaches include tuck, loop myopexy and transposition procedures for horizontal, vertical and torsional forms of misalignment. Adjustable sutures are used routinely in children and adults. The service has a high rate of quaternary referrals from other pediatric and strabismus specialists to manage the rarest and most complex cases, with nearly half of all patients treated having undergone prior strabismus surgery.

Distribution of Strabismus Patients by Age and Surgical Approach

The Strabismus Service at Boston Children’s Hospital offers comprehensive evaluation and treatment for children and adults with strabismus. In 2022, 735 total strabismus procedures were performed by this service. These procedures addressed misalignments that were horizontal, vertical, and torsional in nature. Patients ranged from 5 months to 89 years of age and adjustable sutures were used in 65.6% of all procedures.

Distribution of 2022 Strabismus Patients by Age

Usage of Adjustable Sutures in Strabismus Procedures, by Age

Distribution of Risk Factors in Strabismus Patients

Of the 735 total strabismus surgeries performed in 2022, 360 patients were presented with associated risk factors. Of these 360 patients, the most common risk factors were a history of prior strabismus surgery (47.5%), 4th nerve palsy (10.8%), and divergence insufficiency (4.4%). Other common risk factors were cerebral palsy, Duane syndrome, 3rd and 6th nerve palsies, developmental delays, premature birth, scleral buckle, craniofacial disorders, high myopia, brain tumor, Down syndrome (trisomy 21), and nystagmus with or without poor vision.

Goal-Determined Outcomes

Since the desired surgical outcome depends on the primary indication for surgery, we designed a goal-determined methodology to assess outcomes of horizontal strabismus surgery.^1,2 The reported outcomes include procedures performed at Harvard Medical School ophthalmology affiliates by ophthalmologists with joint appointments at Boston Children’s Hospital and the Massachusetts Eye and Ear Pediatric Ophthalmology and Strabismus Service. Procedures performed by the Massachusetts Eye and Ear Adult Neuro-Ophthalmology service are not included in this analysis.

Before and After Horizontal Strabismus Surgery

Exotropia Outcomes Stratified by Goal

The analysis shown above includes all patients treated in 2022 for horizontal strabismus without exclusion, and therefore, facilitates stratification based on the presence or absence of risk factors (ophthalmic or systemic) that might impact results.

In 2022, of the 735 total strabismus procedures, 243 patients with exotropia underwent strabismus surgery and completed post-operative evaluation. Of these, 34 patients had surgery to preserve or restore binocular vision (binocular potential), 176 had reconstructive surgery for normalizing eye contact, and 27 had surgery to eliminate double vision (diplopia). Outcomes criteria for enhancing binocular potential are the most stringent per criteria by Chang et al¹. Due to the small number, the six procedures performed to resolve torticollis were excluded from this analysis.

Exotropia Outcomes Stratified by Risk Factors

Of the 243 patients treated for exotropia referenced above, 122 had associated risk factors, and 121 had no associated risk factors. Risk factors included: bilateral vision limitation (e.g., albinism), conditions resulting in hyper- or hypotonia, craniofacial anomalies, 3rd nerve palsy, 4th nerve palsy, prior strabismus surgery, Duane syndrome, prior surgery for retinal detachment, Graves’ orbitopathy, antecedent orbital trauma with or without orbital fracture, congenital fibrosis of the extraocular muscles, and simultaneous surgery for nystagmus or vertical strabismus. In the presence of these complicating conditions, 86.1% of strabismus surgeries for exotropia with an associated risk factor and 79.3% without additional risk factors had an excellent or good outcome as defined by the metrics published by Chang et al.¹

Esotropia Outcomes Stratified by Goal

In 2022, of the 735 total strabismus procedures, 331 patients with esotropia underwent strabismus surgery and completed post-operative evaluation. Of these, 79 patients had surgery to restore binocular vision (binocular potential), 152 had reconstructive surgery for normalizing eye contact, and 97 had surgery to eliminate double vision (diplopia). Three procedures performed to resolve torticollis were excluded from this analysis due to the small number.

Esotropia Outcomes Stratified by Risk Factors

Of the 331 patients treated for esotropia referenced above, 136 had associated risk factors and 195 had no associated risk factors. Risk factors included; bilateral vision limitation (e.g. albinism, cataracts, etc.), conditions resulting in hyper- or hypotonia, craniofacial anomalies, 4th nerve palsy, 6th nerve palsy, Duane syndrome, prior strabismus surgery, prior surgery for retinal detachment, Graves’ orbitopathy, antecedent orbital trauma with or without orbital fracture. Despite these complicating conditions, 84.6% of strabismus surgeries for esotropia with an associated risk factor and 91.3% without additional risk factors had excellent or good outcomes as defined by the metrics published by Ehrenberg et al.¹

Scleral Perforation During Strabismus Surgery

Scleral perforation is a potentially significant complication of strabismus surgery, typically occurring during reattachment of eye muscles to the globe. Globe perforation is thought to increase the risk of retinal detachment and endophthalmitis. Scleral perforation is thought to be less common in the modern era, thanks in part to the adoption of “hangback” muscle recessions.⁴ Of the 735 total strabismus procedures performed in 2022, there were zero cases of scleral perforation.

Infection Within 30 Days of Surgery

Intra- or extraocular surgery may be complicated by infection in the form of orbital cellulitis, endophthalmitis, sub-Tenon’s space abscess, subconjunctival abscess, subconjunctival sterile abscess, and cellulitis.

Of the 735 strabismus surgery procedures performed in 2022, there were no post-operative infections within 30 days of surgery.

There were also no post-operative infections for pediatric cataract and ptosis surgery procedures in calendar year 2022, which has been consistent since reporting began in 2013.^5-8