| Residual and recurrent strabismus is common problem found after the strabismus operations that frustrates surgeons, orthoptists, and patients. Recently,the clinical methods have been used to correct residual or recurrent strabismus, including prismatic correction, miotics, botulinum toxin, reoperation and so on. Because reoperation could obtain good postoperative effect, it should be chosen to treat small-to moderate-angle residual or recurrent strabismus by many pediatric ophthalmologists. The surgical management of residual or recurrent strabismus depends on the primary surgery. Bilateral medial or lateral rectus resection is routinely performed on patients having previously undergone bilateral LR recession for intermittent exotropia. Contralateral RR can be used for a patient previously have undergone an RR procedure.The so-called residual refers to undercorrection after strabismus surgery (any deviation≥5°-10°). Patients who undergone the surgical treatment of exotropia or esotropia achieving satisfactory outcome can be defined as surgery recurrence that were found secondary esotropia and exotropia (deviation^15PD) at the follow-up (time≥3months). According to previous reports, the incidence of undercorrection and recurrence after the correction of esotropia varied from20%to40%and the incidence of undercorrection and recurrence after the correction of exotropia varied from22%to59%. The main reasons underlying postoperative undercorrection include inadequate measurement of the preoperative angle of strabismus, inaccurate dosing of surgery, inaccurate intraoperative measurement, inadequate experience of the surgeon, and postoperative recurrence include the deficiency of binocular vision, postoperative uncorrected refractive error, lateral rectus incomitance or underaction and so on. Because strabismus surgery affects not only simple ocular deviations but also complex neuromuscular and sensory systems, many pediatric ophthalmologists have to confront the frustrating postoperative problems and treat them with empirical surgical procedures.Unilateral rectus resection is a safe and effective surgical procedure for treating small-to-moderate angle residual or recurrent exotropia. In particular, this procedure involves short surgical and anesthetic durations and a relatively low incidence of scleral perforation and retinal detachment; more importantly, surgeons may accurately predict the effect of the surgery on residual or recurrent strabismus and remain an intact muscle to provide a possibility for further surgery treatment. In our study, we performed a retrospective study to evaluate the efficacy and safety of unilateral rectus resection in patients. In addition, we analyzed the influence of difference types of strabismus and methods of primary surgery on the surgical outcome. These patients met the following inclusion criteria:1) an age of less than15years;2) the absence of amblyopia;3) the absence of ocular diseases other than exotropia;4) the absence of dissociated vertical deviation (DVD) or oblique muscle dysfunction;5) vertical deviation of5prism diopters (PD) or less;6) the presence of normal eye movement; and7) a follow-up period of longer than6months.Part I The efficacy of unilateral medial rectus resection in children with residual and recurrent exotropiaObjective:To investigate the efficacy of unilateral medial rectus resection in children with residual and recurrent exotropia and analyze the influence of difference types of strabismus and methods of primary surgery on the surgical outcome.Methods:This investigation was a retrospective case series study that examined data from48pediatric patients who underwent unilateral medial rectus resection between January2009and February2013for residual and recurrent exotropia. In total,22of these patients had first undergone bilateral lateral rectus recession,16of these patients had first undergone unilateral lateral rectus recession, and10of these patients had first undergone unilateral lateral rectus recession combined with medial rectus resection. Among the examined individuals,32patients were diagnosed with intermittent exotropia,16patients were diagnosed with constant exotropia. For the patient who undergone bilateral LR recession as a primary surgery, the non-fixation eye acted as operation eye. For the patient who undergone unilateral LR recession as a primary surgery, first eye surgery acted as operation eye. For the patient who undergone R&R as a primary surgery, the contralateral eye acted as operation eye. No patients presented with amblyopia or exhibited associated oblique muscle dysfunction. The patients demonstrated no more than5prism diopters (PD) of vertical deviation. The follow-up period was at least6months. Before and after surgery, deviation was measured by the alternate prism cover test at far (6m) and near (33cm) fixations; in addition, the Worth4-Dot flashlight test and the Titmus stereo test were performed to assess binocular vision. The48patients examined in the study included27males and21females. The mean age of these patients was7.69±2.53years. The patients’ mean deviations before the surgery were18.57±3.96PD (range12-30PD) at far fixation and23.49±5.21PD (range15-35PD) at near fixation. The mean follow-up time was11.99±7.06months. The operative angles for unilateral medial rectus resection were4-4.5mm、5mm、5.5mm、6mm、6.5mm、7mm-7.5mm. The calculated prism corrections were12-14PD、15PD、18PD、20PD、22PD、25-30PD. The standard for successful surgery was defined as a deviation that was+5PD～-10PD.Results:At1day after the surgery, the rate of surgical success was83.3%(40/48), and the rate of undercorrection and overcorrection was4.2%(2/48) and12.5%(6/48), respectively. At6weeks after the surgery, the rate of surgical success was81.25%(39/48), and the rate of undercorrection and overcorrection was12.5%(6/48) and6.25%(3/48), respectively. At the final follow up, the surgical success rate was75%(36/48), and the rate of undercorrection was25%(12/48). No patients were overcorrected. There were no significant differences in the surgical success rate either among pediatric patients who had previously undergone different types of surgery or among patients who had been diagnosed with different types of exotropia (P=.122and P=.50, respectively). The mean correction of deviation at the last follow-up after unilateral medial rectus resection was2.09±1.12PD/mm. No patients presented with lateral incomitance or limited ocular motility. Conclusion:Unilateral medial rectus resection is a safe and effective surgical approach for treating in children with residual and recurrent exotropia. In addition, it may achieve the same surgical effectiveness regardless of the patients’previous surgical procedures or types of exotropia.Part II The efficacy of unilateral lateral rectus resection in children with residual and recurrent esotropiaObjective:To investigate the effect and safe of unilateral lateral rectus resection for treating in children with residual and recurrent esotropia.Methods:In a retrospective, consecutive and interventional case series,24pediatric patients who underwent unilateral lateral rectus resection between December2010and May2013for residual or recurrent esotropia. In total,22of these patients had first undergone bilateral medial rectus recession,2of these patients had undergone unilateral medial rectus recession. Among the examined individuals,10patients were diagnosed with non-accommodative esotropia,5patients were diagnosed with partially accommodative esotropia,4patients were diagnosed with congenital esotropia, and5patients were diagnosed with high AC/A ratio esotropia. No patients presented with amblyopia or exhibited associated oblique muscle dysfunction. The patients demonstrated no more than5prism diopters (PD) of vertical deviation and had the normal eye movement. The follow-up period was at least6months. In preoperative and postoperative, deviation was measured by the alternate prism cover test at far (6m) and near (33cm) fixations; The worth four dot test and Titmus test were performed to evaluate binocularity function examination. The preoperative data of24patients were as follows:The ratio of man and female was14:10; the average age was5.46±1.73year; the mean of distance esodeviation measured was21.25± 6.62PD (range,10to30PD), whereas near esodeviation was23.04+6.58PD (range,14to35PD); the mean follow-up time was12.15±6.07months. The surgical landmarks were defined that ULR resection of6,7,8,9,10mm was performed15,18,20,25,30PD of esotropia. Successful surgical alignment was defined as±10PD of orthophoric in primary and lateral gaze while viewing distance accommodative targets.Results:At the follow-up of6weeks, the rate of surgical success was87.5%(21/24), and the rate of undercorrection was12.5%(3/24). At the final follow up, the surgical success rate was67%(16/24), and the rate of undercorrection was33%(8/24).No patients were overcorrected. The mean correction of deviation at6weeks after unilateral lateral rectus resection was1.91±0.51PD/mm. The mean correction of deviation at the last follow-up after unilateral lateral rectus resection was1.71±0.72PD/mm. No patients presented with lateral incomitance or limited ocular motility.Conclusion:The ULR resection is safe and effective surgical approach for treating in children with residual and recurrent esotropia. |
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