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 Table of Contents  
ORIGINAL ARTICLE
Year : 2017  |  Volume : 18  |  Issue : 3  |  Page : 176-181

Suspension recession of inferior oblique versus graded recession technique in V-pattern strabismus with primary inferior oblique overaction


1 Department of Ophthalmology, Fayoum University, Fayoum, Egypt
2 Department of Ophthalmology, Cairo University, Cairo, Egypt

Date of Web Publication17-Oct-2017

Correspondence Address:
Heba A El Gendy
Department of Ophthalmology, Cairo University, 1 Ibrahim Abou El Naga Street, Nasr City, Cairo - 11727
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/DJO.DJO_3_17

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  Abstract 

Purpose The aim of this study was to evaluate the efficacy of inferior oblique suspension recession ‘modified hang-back’ in cases with V-pattern strabismus and primary inferior oblique overaction (IOOA), compared with standard graded recession technique.
Patients and methods Thirty patients (60 eyes) presenting with V-pattern strabismus with primary IOOA were enrolled and randomized for inferior oblique weakening intervention − that is, suspension recession (group A), or standard graded recession (group B).
Results In group A, the mean postoperative V-pattern exotropia was 4.8±2.7 PD as compared with a mean of 26.42±6.26 PD preoperatively (P≤0.001). Meanwhile, for the esotropic subgroup, the values were 2.57±1.13 and 15.62±4.17 PD, respectively (P≤0.001). For group B patients, the mean V-pattern exotropia was 2±1.5 PD, compared with a preoperative mean value of 23.12±10.66 PD (P≤0.001), and the mean pattern esotropia was 2.28±1.79 PD, compared with a preoperative mean value of 17.14±3.93 PD (P≤0.001), with a highly significant statistical difference between patients within the same group (P≤0.001), as well as between the two groups as regards the exotropic subgroups (P≤0.02). A significant improvement in IOOA was noted in group B, whereas the postoperative hypertropia in lateral gaze was 0.97±1 PD, compared with 5.06±2 in group A (P≤0.001).
Conclusion Although considerable results were achieved with the suspension recession technique, the postoperative impact of the procedure as regards the control of IOOA may be still questionable, with significant superior results of the standard recession technique.

Keywords: graded recession, inferior oblique overaction, pattern strabismus, suspension recession, V pattern


How to cite this article:
Taha RH, El Gendy HA, Kamal MA, El Guindy FM. Suspension recession of inferior oblique versus graded recession technique in V-pattern strabismus with primary inferior oblique overaction. Delta J Ophthalmol 2017;18:176-81

How to cite this URL:
Taha RH, El Gendy HA, Kamal MA, El Guindy FM. Suspension recession of inferior oblique versus graded recession technique in V-pattern strabismus with primary inferior oblique overaction. Delta J Ophthalmol [serial online] 2017 [cited 2021 Oct 16];18:176-81. Available from: http://www.djo.eg.net/text.asp?2017/18/3/176/216925


  Introduction Top


Being a common disorder of ocular motility, primary inferior oblique overaction (IOOA) has been reported in 70% of patients with esotropia and 30% with exotropia, presenting V-pattern strabismus [1],[2],[3].

Weakening of the overacting inferior oblique (IO) muscle has been recommended in cases with clinically significant pattern, with both myectomy and muscle recession widely used [4],[5],[6],[7],[8].

Difficulties for approaching the insertion site of the IO, with the risk of injuring the macular area, as well as the identification of sclera landmarks for the desired amount of recession, led to the rise of modification in IO recession technique [i.e. hang-back recession and further modification (the suspension recession of IO)], a technique that avoids the potential risk of approaching the muscle insertion near the macular area, as well as allows muscle recession with the respect of the original anatomical course of the muscle [9].

In the current study, the authors studied the efficacy of modified hang-back recession (suspension recession) of the IO, as compared with the standard graded recession in cases with V-pattern strabismus with primary IOOA.


  Patients and methods Top


The study was conducted in accordance with the ethical standards in the Declaration of Helsinki 1964 [10], and the approval of our local institutional ethical Committee was obtained.

A full informative written consent was taken from all patients or their guardians, as regards the surgical procedure and the possible complications as well as the agreement to join the postoperative follow-up regimen.

In this prospective, comparative study, thirty patients presenting with V-pattern strabismus with primary IOOA were enrolled and randomized to one of the two groups using simple randomization (i.e. flipping a coin): suspension IO recession (group A) and standard graded IO recession (group B).

Patients meeting the inclusion criteria (i.e. aged ≥ 1 year with V-pattern strabismus and primary IOOA) were recruited from those attending the out-patient clinics in Kasr Al Aini and Fayoum University Hospitals during the period between March 2012 and March 2015.

Patients requiring simultaneous surgery on cyclovertical muscles other than the IO, those with a history of previous muscle surgery, and those with paretic or restrictive strabismus were excluded from the study, as well as cases with considerable refractive elements.

A full comprehensive history was taken from all patients and/or their guardians, and all participants were thoroughly examined for anterior or posterior segment pathologies.

A full motor evaluation for ductions and versions in all cardinal directions of gaze was conducted to exclude cases with restrictive or paralytic elements, and the angle of deviation was measured with the alternate prism and cover test for cooperative patients or the modified Krimsky method for uncooperative patients.

Sensory evaluation using Worth 4-Dot Test,  Bagolini lens More Detailses, and stereoacuity testing was conducted whenever possible.

Cycloplegic refraction was scheduled during the initial examination, to exclude cases of refractive etiology, together with examination for fundus torsion to confirm the diagnosis of primary oblique overaction.

IOOA was graded on a four-point scale ranging from +1 to +4, and patients were further subgrouped into V-pattern exotropia and V-pattern esotropia in either group, based on primary position.

Surgical protocol

All patients were operated under general anesthesia using an operating microscope at low magnification by the same surgical team (R.H.T. and H.A.E.G.). The IO muscle was surgically approached through a conjunctival fornix incision, after the application of a 4/0 bridle suture across the lateral rectus muscle to help the fixation of the globe as well as the proper exposure of the surgical field.

In group A, suspension IO recession (modified hang-back) technique was performed as described by Kumar et al. [9]. Whereas, the planned amount of recession according to the degree of IOOA was measured on both arms of the 6/0 vicryl sutures, passing through both cut ends of the muscle:
  1. A double-armed 6/0 vicryl suture was passed 5 mm from the insertion site through the width of the IO muscle, with locking bites on both ends.
  2. The same sutures were then passed proximally 3 mm from the insertion site in a loose manner.
  3. The loose suture loops were created between the proximal and distal suture bites on the muscle.
  4. The intermediate part of the IO muscle that served between the distal and proximal sutures was then cut, and the proximal part of the served muscle was left suspended from the distal muscle.
  5. The amount of the planned recession was then measured on both arms of the vicryl 6/0 sutures, and the two proximal ends were tied on a smooth forceps the same way as in the regular hang-back technique.
  6. The two ends of the cut IO muscle were then allowed to retract with the two ends expected to stay recessed according to the amount of recession measured on the two arms of the suspending suture, preserving the anatomical course of the muscle.


In group B, the IO graded recession technique was performed, with the amount of recession decided based on the degree of IOOA, using double-armed 6/0 vicryl sutures [11].

The time from hooking of the IO muscle to the end of suture securing for the planned amount of recession was measured in all cases, for further evaluation.

Horizontal muscle surgery was performed thereafter according to the planned protocol for horizontal deviation in the primary position, whereas no offset of the horizontals was carried out in any of the cases included in the current study.

Postoperative follow-up

All cases were examined by a masked observer for ocular alignment in the primary position, ocular motility, pattern strabismus, degree of residual IOOA, and degree of hypertropia in lateral gaze position on the first day postoperatively whenever possible and during the follow-up visits thereafter.

All eyes received postoperative routine medications in the form of topical steroid/antibiotic combination for 2 weeks, and all patients were scheduled for follow-up visits at 1 week, 1 month, and then monthly for 6 months postoperatively.

Statistical analysis

Data were collected and statistically analyzed using the SPSS, version 16 (SPSS Inc., Chicago, USA), software program. For categorical variables (e.g. sex) percent distribution were used, whereas for continuous variables (e.g. age and angle of deviation) frequency distribution, mean, median, range, and SD were used.

The changes within groups during the follow-up period were evaluated using repeated measures of analysis (analysis of variance).

Comparisons between the two groups were made using paired samples t-test for continuous variables and the χ2-test for categorical variables, and statistical significance was computed. A P value less than or equal to 0.05 was considered to be of statistical significance.


  Results Top


In the present prospective, comparative study, 30 patients (60 eyes) presenting with V-pattern strabismus with primary IOOA, who met the planned inclusion criteria were enrolled and scheduled for surgical IO weakening intervention. Patients were then randomly divided into two groups of 15 patients each: suspension IO recession (group A) or standard graded recession (group B).

The demographic data for patients in both groups and family history of ocular misalignment are summarized in [Table 1], with no statistical differences between patients in the two groups.
Table 1 Demographic data

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Preoperative data

In group A, seven patients presented with exotropia in primary position and eight patients presented with esotropia, compared with eight patients with exotropia and seven patients with esotropia in group B, with no statistical differences.

The mean preoperative measured angles of horizontal deviations in the primary position is presented in [Table 2].
Table 2 Preoperative mean values of ocular alignment

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As regards the pattern of deviation, the mean values of the differences of measured angles in 25° upgaze and downgaze positions are summarized in [Table 2], with no significant statistical difference between the two groups (P≤0.5).

The degree of IOOA was graded in a scale of +1 to +4, with two (13.33%) patients in group A showing +2 IOOA, eight patients presenting with +3, with an incidence of 53.33%, and five (33.3%) patients presenting with +4 IOOA, compared with three (20%) patients, seven (46.66%) patients, and five (33.3%) patients in group B, respectively. There was no statistical difference between the two groups (P≤0.3). Moreover, the degree of hypertropia was measured in lateral gaze to quantify IOOA, preoperatively ([Table 2]).

Operative data

Group A: A bilateral suspension recession technique (i.e. modified hang-back recession of the IO together with bilateral rectus muscles recession) that ranged from 6.5 to 9.5 mm was performed in seven V-pattern exotropic patients, and bilateral medial rectus muscle recession that ranged from 4 to 6.5 mm was performed in eight patients with V-pattern esotropia.

Surgical difficulties were encountered during the step of adjusting the suture knots at the desired measurements for the amount of the planned recession, as the two ends of the cut IO muscle were not comfortably fully stretched and followed the exact course and direction of the muscle in 18 (60%) eyes, despite meticulous dissection of the muscle.

Group B: The standard graded IO recession according to the degree of preoperative overaction was performed in eight V-pattern exotropic patients together with bilateral lateral rectus recession that ranged from 5 to 10 mm, except for one patient, in whom the surgeon added bilateral medial rectus resection 6.5 mm due to a larger preoperative angle (≃60 ΔD). Meanwhile, the same technique was performed in seven V-pattern esotropic patients together with bilateral medial rectus recession that ranged from 4 to 7 mm.

The mean±SD duration of IO muscle exploration and recession was 37.8±5.36 min for group A patients, compared with a mean duration 26.16±3.36 in group B, and it was noted to be statistically nonsignificant (P≤0.2).

Postoperative data

All patients were requested to attend their scheduled follow-up visits at a minimum of 6 months postoperatively, with documented satisfactory postoperative results defined as postoperative horizontal orthophoria less than or equal to 10 PD in the primary position, with no residual IOOA; the documented postoperative alignment measurements were considered around the eighth week postoperatively.

The postoperative alignment details in the primary position, the mean V-pattern values, and hypertropia in lateral gaze are summarized in [Table 3], with no significant differences between the two groups of patients as regards the ocular alignment in primary position. However, statistically significant differences were noted when evaluating hypertropia measurements in lateral gaze, as well as the mean V-pattern angle measurements in the V-pattern exotropia subgroup.
Table 3 Postoperative mean values of ocular alignment

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Moreover, the postoperative results were compared with the preoperative data in either groups. The data are summarized in [Table 4].
Table 4 The preoperative and postoperative mean values of ocular alignment in both groups

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A highly statistically significant difference has been noted, when comparing the preoperative and postoperative data within each group individually by the end of the follow-up period (P≤0.0001).

Statistical analysis of the post-operative data compared to the pre-operative data revealed statistical differences , regarding the measured hypertropia in lateral gaze, with better results were shoen in group B (P≤0.001).

Moreover, a significant postoperative improvement in V-pattern deviation was noted in the exotropic subgroups with better clinical results achieved in group B (P≤0.02).

As regards the residual IOOA, patients in group A showed residual IOOA that ranged from +1 to +3, with five (33.33%) patients presenting with +1 residual IOOA, five (33.33%) patients presenting with +2 residual IOOA, and four (26.66%) patients presenting with +3. A second procedure in the form of IO myectomy was considered for the residual IOOA by the end of the follow-up.

Residual IOOA from 0 to +1 was detected in patients in group B, with seven (46.7%) patients having no overaction and eight patients with +1. It was highly significant compared with those in group A (P≤0.002).

Postoperative granuloma formation and allergic reaction were recorded in four eyes in group A patients and in three eyes in group B. Further, a conjunctival inclusion cyst was reported in two eyes compared with one eye in group B.


  Discussion Top


The prevalence of pattern strabismus in patients who presented with horizontal muscle strabismus has been reported at a rate of 12.5–50% in some publications and up to 87.7% in others [12],[13], with the exact pathophysiology not well established. However, oblique muscle dysfunction has been considered as the most popular theory, with a reported satisfactory success rate of oblique muscle surgery in the management of such disorder [14],[15].

V-pattern strabismus with IOOA has been the patient of considerable research, with different surgical approaches proposed for weakening of the overacting oblique muscle [16].

Kumar et al. [9] described their technique for weakening the overacting IO muscle [i.e. a modified hang-back (muscle suspension) recession]. However, review of the published literature for similar attempts failed to reach other publications. Hence, the present study was conducted in an attempt to evaluate the practical efficacy of this procedure, comparing the results with the previously published, as well as with the results of the standard graded recession technique, in cases with V-pattern strabismus and primary IOOA.

In the current study, the authors performed bilateral IO recession (i.e. suspension recession in group A and standard graded recession in group B) as all cases presented with an almost symmetrical degree of IOOA.

For the suspension recession group, the authors reported a mean improvement of V-pattern exotropia from 26.2 PD to a mean of 4.85 PD postoperatively, whereas in the V-pattern esotropia subgroup an improvement from a mean of 15.6 PD to a mean of 2.57 PD has been noted.

The current study results have been compared with those reported by Kumar et al. [9], who reported an average V-pattern correction of 19 PD for the V-exotropia group, and 22 PD for the V-esotropia group, as compared with 22 and 13 PD, respectively, in the current study. The mean correction of IOOA showed an improvement from 18.86 PD to a mean of 5.06 PD by the end of the follow-up, with a mean correction of 13 PD, compared with a mean correction of 18 PD in their published series. The average residual postoperative IOOA (i.e. hypertropia in lateral gaze) was 5Δ±2, compared with 2Δ or less in the study by Kumar et al. [9].

The discrepancy between the current study results and that reported by Kumar et al. [9] could be attributed to the discrepancy in the degree of preoperative IOOA, as the current study included operated cases with moderate-to-severe IOOA, as compared with moderate cases in the other series.

On the contrary, in the standard graded recession group, the V-pattern exotropia improved from a mean of 23.12 PD to a postoperative mean of 2 PD, and from 17.14 to 2.28 PD, respectively, for the esotropic subgroup. Moreover, the mean correction of IOOA improved from 17.93 PD to a postoperative mean of 0.97 PD, whereas overaction disappeared completely in seven (46.7%) patients and a trace of +1 was noted in eight (53.3%) patients.

The current study results were superior to that reported by Parkash et al. [17], who obtained an average correction of 11 PD in V exotropia and 9 PD in V esotropia after bilateral recession, as well as other published studies, with an average reported change of 11.47 and 15.4 PD, respectively, and a residual of 9.13 and 14.07 PD postoperatively [18].

In fact, the previous series included patients of both primary and secondary IOOA, and hence a direct correlation with the current study results might be not significant, explaining the superiority of the current study results compared with theirs.

Kamlesh et al. [19] reported a mean correction of IOOA of 23.83 and 19.83 PD in cases of V exotropia (six patients) and V esotropia (four patients), respectively, by the end of a follow-up period after bilateral 10 mm IO recession. This was comparable to the current study results, as regards the exotropia patients; however, the difference in results for the esotropic patients might be attributed to the discrepancy in the number of patients in both series.

As regards the comparison between the two weakening techniques applied in the current study, the authors noted a considerable improvement in all cases, as regards the correction of the V pattern as well as the correction of IOOA, in both groups. However, more improvement was noticed with the standard recession, as compared with the modified hang-back technique. The mean residual IOOA was 0.97 and 5 PD, respectively; it was considered statistically significant.

The difference in the results between the two groups may be attributed to the accurate attachment of the IO muscle to the sclera in the graded recession technique, contrary to the other in which the two ends of the muscle were left suspended with the suture, and can make the reattachment site to the sclera uncertain.

Although considerable success was achieved with the suspension recession technique, the postoperative impact of the procedure as regards the control of IOOA may still be questionable, with significant superior results of the standard recession technique. Moreover, technical difficulties as regards the achievement of the desired measurements on the two ends of the suspending sutures as well as the proper relief of both cut ends of the muscle at the planned amount of recession needed may explain the lower results compared with the standard recession technique with secure suturing of the recessed muscle insertion to the sclera.

Therefore, in the authors’ experience, the standard graded recession technique may be considered as being simple and easily mastered with favorable postoperative results in cases with pattern with IOOA compared with the suspension recession technique.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

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Modi NC, Jones DH. Strabismus: background and surgical techniques. J Perioper Pract. 2008; 18:532–535.  Back to cited text no. 1
    
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Choi DG, Chang BL. Electron microscopy study on overacting inferior oblique muscles. Korean J Ophthalmol 1992; 6:69–75.  Back to cited text no. 2
    
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Caldeira JA. Some clinical characteristics of V-paterrn esotropia and surgical outcome after bilateral recession of the inferior oblique muscle: a retrospective study of 22 consecutive patients and a comparison with V-paterrn esotropia. Binocul Vis Strabismus Q 2004; 18:139–150.  Back to cited text no. 3
    
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Kumar K, Prasad HN, Monga S, Bhola R. Hang-back recession of inferior oblique muscle in V-pattern strabismus with inferior oblique overaction. J AAPOS 2008; 12:401–404.  Back to cited text no. 9
    
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Urist MJ. The etiology of the so called A and V syndromes. Am J Ophthalmol 1958; 46:835.  Back to cited text no. 12
    
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Kushner BJ. The role of ocular torsion in the etiology of A and V patterns. J Pediatr Ophthalmol Strabismus 1985; 22:171–179.  Back to cited text no. 15
    
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Dadeya S, Kamlesh F, Bhola R. A modified hangback recession technique for horizontal strabismus. J Pediatr Ophthalmol Strabismus 2002; 39:195.  Back to cited text no. 16
    
17.
Parkash P, Menon V, Nath J. Surgical management of A and V pattern. Ind J Ophthalmol 1983; 31:463.  Back to cited text no. 17
    
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