|Year : 2022 | Volume
| Issue : 2 | Page : 66-71
Graded recession technique versus myectomy in management of inferior oblique muscle overaction
Department of Ophthalmology, Helwan University, Cairo, Egypt
|Date of Submission||25-Nov-2021|
|Date of Acceptance||26-Nov-2021|
|Date of Web Publication||08-Jul-2022|
MD Karim Gaballah
Department of Ophthalmology, 2 Morisson Street, Rouchdy, Alexandria 21111
Source of Support: None, Conflict of Interest: None
Aim The aim of this study was to compare two surgical techniques of inferior oblique muscle weakening in the management of inferior oblique overaction whether primary or secondary, that is, inferior oblique myectomy and graded inferior oblique muscle recession.
Patients and methods This is a randomized prospective study, performed in Alexandria, Egypt, that included cases of inferior oblique muscle overaction, whether primary or secondary, starting on May 2020. It included 40 patients, divided into two groups: group I included 20 patients who were managed by inferior oblique myectomy, and group II included 20 patients who were managed by graded inferior oblique muscle recession, according to the clinical grading of overaction.
Results The results of the two groups were compared, and it was found that the results were comparable as the final outcomes of correction of hypertropia were satisfactory in both groups.
Conclusion As the results in both techniques have no significant difference, it is recommended that each surgeon should perform his/her preferred technique.
Keywords: graded recession, hypertropia, inferior oblique overaction, myectomy
|How to cite this article:|
Gaballah K. Graded recession technique versus myectomy in management of inferior oblique muscle overaction. J Egypt Ophthalmol Soc 2022;115:66-71
|How to cite this URL:|
Gaballah K. Graded recession technique versus myectomy in management of inferior oblique muscle overaction. J Egypt Ophthalmol Soc [serial online] 2022 [cited 2022 Sep 28];115:66-71. Available from: http://www.jeos.eg.net/text.asp?2022/115/2/66/350249
| Introduction|| |
Overaction of the inferior oblique muscle, presenting with hypertropia of the eye in adduction position, is one of the common presenting clinical pictures in strabismus. It could be mild and unnoticeable, except when examined by an ophthalmologist, and also does not cause bad cosmesis, so does not require any interference or management and needs only follow-up, or could be more important so as to be cosmetically unacceptable and requiring surgical correction.
Inferior oblique overaction (IOOA) may be primary or secondary. Primary overaction is increased inferior oblique muscle function of unknown cause accompanying other forms of strabismus or it might occur as an isolated IOOA without other forms of strabismus .
It could be primary as the type accompanying congenital esotropia is an important percentage of cases and could be secondary to superior oblique muscle palsy. These two types are clinically different, as the latter is usually accompanied by abnormal head posture, but in the management of the two types, inferior oblique muscle weakening is common in most cases.
Several surgical procedures have been reported for weakening inferior oblique muscles. The most commonly used surgical techniques are myectomy, recession, and myotomy ,.
Inferior oblique muscle weakening is performed by surgeons in different techniques according to every surgeon’s preference; some surgeons perform inferior oblique muscle myectomy, where part of the bulk of the muscle is excised and the rest of the muscle is left to recede back and reattach to the sclera in an unplanned new insertion, whereas other surgeons prefer graded inferior oblique muscle recession where the muscle is disinserted and then reattached into a new insertion in the sclera, in relation to the inferior rectus muscle, in different sites according to the grade of overaction .
| Aim|| |
The aim of this study was to compare two surgical techniques of inferior oblique muscle weakening in the management of inferior oblique overcation: the first one is the inferior oblique muscle myectomy, and the second one is the graded recession and suturing to the sclera at a pre-planned new insertion, with recession graded according to the preoperative clinical grading of overaction.
| Patients and methods|| |
This is a randomized prospective study of cases of IOOA, performed in Alexandria, Egypt, starting from May 2020 till April 2021. It included 40 cases of strabismus presenting with IOOA either primary or secondary that was cosmetically unaccepted and required surgical correction.
The following were the inclusion criteria:
- Cases of strabismus having inferior oblique muscle overaction.
- Either unilateral or bilateral.
- Primary or secondary IOOA.
- Cosmetically nonaccepted by the patient.
- Not previously operated from vertical strabismus.
- Patient accepting to be included in the study.
The following were the exclusion criteria:
- Previously operated for vertical strabismus.
- Uncooperative patients.
- Patients refusing to be included in the study.
Patients were divided into two groups.
Group I: where the management was by inferior oblique muscle myectomy, and this group included 20 patients.
Technique: the inferior oblique muscle is exposed and dissected from surrounding attachment to inferior rectus muscle, disinserted from its scleral insertion, and an 8-mm portion is excised. The remaining proximal part of the muscle is left to recede back into the sheath.
Group II: where the management was by graded recession of the inferior oblique muscle, according to the clinical grading of overaction, of Kennith Wright, where the inferior oblique muscle is disinserted and reattached to the sclera in a specific site in relation to the lateral border of inferior rectus muscle insertion, and this group included 20 patients.
All patients were documented, and the results were tabulated for personal data, preoperative clinical picture and staging, and postoperative clinical picture within 1 week postoperatively and then after 3 months.
The two groups were compared regarding the operation safety, complications, and the postoperative results in early and late postoperative periods.
Cases were considered cured if the postoperative overaction of the inferior oblique was equal to or less than +1.
An informed written consent was taken preoperatively from adult patients, or from the guardians of patients aged less than 18 years, to be included in the study, according to the ethical committee of Alexandria University.
| Results|| |
It included 20 patients, comprising 14 females and six males. Their age ranged from 3 to 32 years. They presented with overaction of inferior oblique, with hypertropia in adduction. Eight cases were unilateral, and 12 cases were bilateral, totalling 32 eyes. This group was treated by inferior oblique myectomy technique, regardless of the clinical grading of overaction.
[Table 1] shows the preoperative grading and postoperative results of inferior oblique myectomy. There were 10 eyes of grade II, and 11 eyes of grade III, and 11 eyes of grade IV that were subjected to operation by inferior oblique myectomy technique.
|Table 1 Clinical grading of inferior oblique overaction in group I, preoperative and postoperative|
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The postoperative results of these eyes, after 3 months, were as follows: no overaction in 18 eyes, grade I overaction in 12 eyes, and grade II overaction in two eyes. So, 30 eyes were considered cured, and only two eyes with grade two overaction postoperative were considered residual, constituting 6.25% of cases treated by myectomy. So, the cure rate was 93.75% in group I ([Figure 1]a, b).
|Figure 1 (a) Right IOOA grades III–IV. (b) Postmyectomy no overaction. IOOA, inferior oblique overaction.|
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Four patients of the bilateral IOOA had secondary IOOA owing to superior oblique muscle palsy. Their ages were 3, 6, 7, and 26 years. Postoperatively, they had corrected hypertropia as well as the abnormal head posture, but residual hypertropia grade I in three cases in one of the eye ([Table 2]).
|Table 2 Clinical grading of eyes with secondary inferior oblique overaction, in bilateral cases, in group I, preoperative and postoperative|
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Four patients of the 12 patients had bilateral IOOA and were secondary to superior oblique muscle palsy, and had unequal elevation in adduction of the two eyes preoperatively. After being operated by the inferior oblique myectomy method for both inferior oblique muscles, with the same amount of muscle excision, regardless of the clinical grading of overaction, the result was a residual hypertropia in one eye postoperative in three patients but much less than preoperatively, minimal, and not disfiguring, and considered cured. Cases were considered cured when postoperative IOOA reached +1 or less ([Figure 2]a, b).
|Figure 2 (a) Right IOOA grade III preoperative. (b) Postmyectomy, right IOOA grade I. IOOA, inferior oblique overaction.|
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This group included 20 patients having inferior oblique muscle overaction. There were 16 females and four males, and their age ranged from 4 to 35 years. A total of 11 cases were unilateral and nine cases were bilateral, totalling 29 eyes. This group was treated by graded inferior oblique muscle recession according to the clinical grading of overaction.
[Table 3] shows the preoperative grading of IOOA and postoperative results of inferior oblique graded recession according to the Kenneth Wright graded recession technique. There were three eyes of grade I, eight eyes of grade II, 11 eyes of grade III, and seven eyes of grade IV that were subjected to operation by inferior oblique graded recession technique according to the clinical grade of IOOA ([Figure 3]a–c and [Figure 4]a–c).
|Table 3 Clinical grading of inferior oblique overaction in group II, preoperative and postoperative|
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|Figure 3 (a) Bilateral SO palsy. (b) Right IOOA grade IV. (c) Left IOOA grade III. IOOA, inferior oblique overaction; SO, superior oblique.|
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|Figure 4 (a) Bilateral SO palsy. (b) Right IOOA grade IV. (c) Left IOOA grade IV. IOOA, inferior oblique overaction; SO, superior oblique.|
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The postoperative result of these eyes, after 3 months, was as follows: no overaction in 26 eyes, grade I overaction in two eyes, and grade II in one eye (3.5%), so the cure rate in group II was 96.5%.
Among the nine bilateral cases, five patients had bilateral primary IOOA and four patients had bilateral secondary IOOA with head tilt toward the less affected side, with chin depression, owing to superior oblique palsy, where two of them had grade III and two had grade IV overaction, in one eye, and grade I and grade II in the other eye. They were totally corrected postoperatively, with correction of the abnormal head posture. Their age was 5, 6, 16, and 29 years ([Figure 5]a–c and [Figure 6]a–c, [Table 4]).
|Table 4 Clinical grading of eyes with secondary inferior oblique overaction, in bilateral cases, in group II, preoperative and postoperative (after graded recession)|
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|Figure 5 (a) Preoperative. (b) Right IOOA grade III. (c) Left IOOA grade II. IOOA, inferior oblique overaction.|
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|Figure 6 (a) Postgraded recession. (b) Right IOOA grade 0. (c) Left IOOA grade 0. IOOA, inferior oblique overaction.|
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Four patients of the nine patients had bilateral IOOA, secondary to superior oblique muscle palsy, and had unequal elevation in adduction of the two eyes preoperatively. After being operated by inferior oblique graded recession method for both inferior oblique muscles, according to the clinical grade of overaction, the result was no hypertropia in all patients in the postoperative period, especially that two of these patients had grade I overaction in one eye and grade III in the other eye preoperatively.
When comparing the cure rate in the two groups, it was 93.75% in group I and 96.5% in group II.
The cure rate in group I was 93.75% and in group II it was 96.5%. No cases of antielevation syndrome were detected in the postoperative follow up in both groups.
The mean operation time in group I was 6.25±0.58 min in the myectomy method, whereas the mean operation time in group II was 7.52±0.62 min in the graded recession method.
| Discussion|| |
The results of the present study show the effect of each surgical method, where both of them could effectively reduce the IOOA; however, the rate of weakening was greater in the graded recession technique, and this was detected in the postoperative examination and in the follow-up, as the outcomes were slightly better in this method. The mean IOOA grades were similar between the two groups before the operation, but IOOA showed a slightly greater cure rate (96.5%) postoperatively in the graded recession method group, more than the inferior oblique myectomy method (93.75%) but with no significant difference.
In a study of Moon and Lee  where cases of unilateral superior oblique palsy were studied and graded recession and anteriorization was performed to reduce the overaction of inferior oblique muscle, they had a success rate of 81.8%, which is much less than our results.
In another study by Singh and Agarwal , the success rate of recession of inferior oblique was 100%, which is greater than our results, but this can be explained by the parameters they used. They considered a successful surgery when the postoperative IOOA reached a grade of +2 or less, whereas in our study we considered a successful surgery when the postoperative IOOA reached +1 or less. So, to compare our results with Singh and Agarwal, we have to use the same criteria of success, and if we apply +2 or less, the postoperative results of graded recession in this study will be 100%.
In the study by Masaya-anon et al.  on the effect of inferior oblique recession in secondary IOOA, the overaction was reduced from +3 to +0.4 after surgery. In the present study, the final IOOA was successful in 93.75% in group I and 96.5% in group II, which is comparable to their study.
Ghazawy et al.  compared the effect of myectomy and anterior transposition on IOOA and found that these two methods led to almost similar results. Min et al.  reported a success rate of 25% for the myectomy method, which is much less than our results of myectomy technique, where the success rate reached 93.75%.
Our results were different than the study of Nabie et al. , who showed more successful results of myectomy than graded recession in reducing IOOA.
On the contrary, inferior oblique myectomy has shown to be technically more easy, with less manipulation, that is, no scleral suturing, and so could be considered as technically easier, with no significant difference in the results between the two techniques.
Regarding the mean operation time, it was less in group I of myectomy (6.25±0.58 min in the myectomy method), whereas the mean operation time in group II (graded recession method) was 7.52±0.62 min. Only one previous study compared the operation time of the two procedures. Nabie et al.  found that the mean operation time was 6.49±0.14 min in group I and 5.80±0.86 min in group II. This difference in operation time as one operation is more rapidly performed than the other, in our opinion, is not considered as an advantage of myectomy; this is because rapidity is not important, especially when we look at the advantage of anterior transposition and recession over myectomy in preservation of the muscle.
Preservation of the inferior oblique muscle and suturing it to a known position in graded recession is considered a great advantage if one needs to reoperate on inferior oblique muscle such as DVD. So, recession and anterior transposition may be considered a better option .
Sanjari et al.  in a retrospective study found a more success rate for myectomy group than graded recession group, which was different than our results.
| Conclusion|| |
Both myectomy and graded recession of inferior oblique muscle can effectively reduce IOOA grade, while the success rate of graded recession method was found higher than myectomy method.
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Conflicts of interest
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2], [Table 3], [Table 4]