|Year : 1983 | Volume
| Issue : 5 | Page : 463-469
Surgical management of A & V patterns
Prem Prakash, V Menon, J Nath
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, A.I.I.M.S., New Delhi, India
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, A.I.I.M.S., New Delhi 110 029
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Prakash P, Menon V, Nath J. Surgical management of A & V patterns. Indian J Ophthalmol 1983;31:463-9
Recognition of change in the horizontal deviation in up and down gaze had been known since long with occasional reference in literature but for long not much significance was attached to this observation. Surgical management of this phenomenon is rather complex because of its varied picture and presentation. Non recognition of this phenomenon has resulted in poor surgical results in the past.
Surgery of horizontal recti in the form of recession resection procedures  their upward or downward displacement ,, and slanting technique has been advocated. Whenever the oblique muscle dysfunction was incriminated , oblique muscles were operated. Vertical recti have also been operated upon to correct this pattern .
All these three approaches i.e. surgical treatment on horizontal recti, vertical recti and oblique muscles have been utilised for evaluation of their effects in this paper.
| Methods and Material|| |
102 cases of AN. Pattern have been taken from the Ocular Motility and Amblyopia clinic of Dr. R.P. Centre for Ophthalmic Sciences. A complete orthoptic check after due refractive correction was undertaken. A difference of 15 prisms or more in V phenomenon and 10 prisms or more in A phenomenon in up and down position measurements was taken, as criteria for designating these patterns.
The surgical methods chosen were dependent upon presence or absence of oblique dysfunction In case there was oblique dysfunction it was always tackled along with appropriate horizontal muscle surgery wherever needed. The type of horizontal recti surgery was chosen as it would have been without the presence of A & V phenomenon and based on this conclusion the modification of horizontal recti surgery was undertaken for correction of A & V pattern. The vertical recti were under taken only in cases of Y pattern.
| Observations|| |
A total of 102 cases were undertaken for surgery out of which following is the distribution of the type of A & V pattern.
V EXO - 53 cases
A EXO - 12 cases
V ESO - 22 cases
A ESO - 12 cases
Y EXO - 2 cases
X Phenomenon - 1 case
Total 102 cases
[Table - 1] shows the surgery undertaken in V pattern. It is noted that maximum average correction was obtained by combined procedure of lateral rectus recession with inferior oblique weakening. [Figure - 2] A ± B There were two cases in which lateral rectus recession was also accompanied by upward displacement and these two cases showed the maximum correction upto 24 prisms. Bilateral inferior oblique recession alone could correct on an average 11 ∆ and unilateral inferior oblique and lateral rectus recession could achieve an average of 6 ∆ only. Bilateral slanting surgery on medial or lateral rectus muscle could achieve an average correction of 7 and 8 ∆ respectively. However unilateral slanting recession and resection could achieve an average correction of 10 ∆. Bilateral vertical displacement of lateral recti achieved an average of 12 ∆ [Figure - 1]. Unilateral recession and resection could achieve still better average of 15 ∆.
In two cases of Y exo- deviation, horizontal displacement of superior recti gave an average correction of 10 ∆.
[Table - 2] shows the results of various procedures undertaken in 12 cases for the correction of A-Exo. It was noted that in cases where superior oblique showed overaction and it was weakened bilaterally it has shown the most effective correction to a maximum extent of 34 ∆ and with an average of 24 ∆ [Figure - 3] A & B. Rest of the procedures like slanting operation and vertical displacement on the horizontal recti gave an average correction of 10.5 ∆ to 12 ∆. However it may be noted that vertical displacement gave higher average correction than slanting technique.
[Table - 3] shows the surgical results on 22 cases of V-Esotropia. It is noted that maximum correction in V pattern (18) ∆ could be achieved by combined inferior oblique and medial rectus recession with an average correction of 14 ∆ [Figure - 5] A & B. Bilateral medial rectus recession with vertical displacement 12 ∆ for resulted in second best average correction of [Figure - 4] Bilateral inferior oblique recession alone gave an average correction of 9 ∆ and slanting operation gave an average of 8 ∆ (unilateral surgery) and 10 (Bilateral surgery).
[Table - 4] shows the results of surgical procedures undertaken in 12 cases of A Eso deviation. Maximum corrections of 15∆ with an average of 12∆ could be achieved with vertical displacement. Bilateral medial rectus recession with slanting insertions and unilateral slanting recession and resection gave practically similar results of an average of 8-9∆. Bilateral lateral rectus resection with slanting insertion gave an average correction of 12∆.
In one case of X pattern with manifest overaction of both superior and inferior oblique muscles, weakening of all the four obliques gave a satisfactory result giving a correction of 24 ∆ in down gaze and 15 ∆ in up gaze. [Figure - 6] A & B
| Discussion|| |
There are many aetiological factors blamed for the genesis of A & V pattern.
Accordingly the surgical treatment of these cases also varies widely. It may be that cases of A & V pattern present a varied picture in which vertical and cyclo-vertical muscle dysfunction may or may not be present. However horizontal muscle dysfunction cannot be easily demonstrated in these cases. The present study reveals that whenever oblique dysfunction is present, and it is surgically weakened, very satisfactory and desirable results are achieved. The superior oblique weakening procedures produce far more correction in cases of A. Exo phenomenon compared to the inferior oblique recession in V phenomenon. In V Eso pattern a four muscle surgery of bilateral inferior oblique weakening along with medial rectus recession produced very satisfactory results. Similarly in V-Exo pattern with bilateral inferior oblique overaction, its weakening procedures along with recession of lateral rectus is an effective procedure. Its effectivity is further enhanced along with upward displacement of lateral recti as was evidenced in two cases with V-phenomenon with a maximal correction of 24∆.
Horizontal surgery with vertical displacement (in cases where there was no vertical or cyclovertical dysfunction) proved to be more effective than the slanting procedure in all types of A.V. pattern except in A Eso pattern where, slanting procedures gave better results than vertical displacement. Slanting technique is easier to perform without any complications but has certain limitations e.g. in a case with recession of 9-10 mm of lateral rectus, the lower end of lateral rectus can not be posteriorly placed because it would than be lying on the inferior oblique muscle.
Similarly in medial rectus surgery one hesitates to recess the lower end more than maximally permitted in functional cases for the fear of producing a convergence weakness. However in such cases vertical displacement, especially when higher correction for A & V pattern is needed, is desirable. The vertical displacement of horizontal muscles creates in mind the fear of introducing vertical elements in horizontal strabismus. This fear is unwarranted as no significant vertical element is introduced with a displacement of 5-6 mm. However one should be very precise in isolating the muscles before vertically displacing them, or else the fascial attachment not severed properly may give rise to certain mechanical limitations to ocular rotation. As a matter of fact some limitations of movement in a vertically displaced muscle have sometimes been noticed. Though in A.V. phenomenon, bilateral surgery is by and large-advocated but even unilateral surgery when indicated can also correct it to a desirable extent. Vertical displacement with unilateral recession resection procedures have proved more effective than the unilateral recession resection procedure with slanting insertions.
| Summary|| |
102 cases of A & V phenomenon have been surgically treated with various surgical procedures on horizontal, vertical and cyclovertical muscles. It is seen that these cases with cyclovertical muscle affection can be effectively treated by tackling them alone or in association with the horizontal muscles. The horizontal muscles are also effective though to a lesser extent when vertically displaced or inserted in a slanting fashion. Unilateral procedures with vertical displacement or slanting insertions of the horizontal muscles are also effective in reducing the A.V. pattern.
| References|| |
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[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6]
[Table - 1], [Table - 2], [Table - 3], [Table - 4]