|Year : 2013 | Volume
| Issue : 4 | Page : 239-244
Inferior rectus tucking versus combined superior rectus recession with posterior fixation suture (faden) for the treatment of dissociated vertical deviation without inferior oblique overaction
Mohamed Mostafa K Diab
Department of Ophthalmology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
|Date of Submission||15-May-2013|
|Date of Acceptance||05-Sep-2013|
|Date of Web Publication||28-Apr-2014|
Mohamed Mostafa K Diab
MD, 42 El kasr El Ainy st. Dar El Hekma, Ain Shams University, Cairo
Source of Support: None, Conflict of Interest: None
To compare the efficiency of inferior rectus tucking versus combined superior rectus recession with posterior fixation suture (Faden) for the treatment of dissociated vertical deviation (DVD) without inferior oblique overaction.
Patients and methods
In this prospective study, 50 consecutive patients with DVD and without inferior oblique overaction were allocated randomly in their order of presentation to two groups; each group included 25 patients. The patients in group I were subjected to combined bilateral superior rectus recession and the Faden procedure (posterior fixation) and the patients in group II were treated by bilateral inferior rectus tucking (plication).
DVD improved significantly (P < 0.05) in the two groups of the study. In group I, the mean vertical deviation improved from 18.21 ± 4.73 prism diopter (PD) preoperatively to 7.82 ± 5.61 PD 9 months after surgery (P < 0.05), with a mean correction of vertical deviation of 10.21 ± 3.52 PD and a mean correction of asymmetry of 2.1 ± 1.6 PD. Four patients needed inferior rectus tucking for residual or recurrent manifest DVD. In group II, the mean vertical deviation improved from 17.97 ± 6.89 PD preoperatively to 6.97 ± 5.46 PD 9 months after surgery (P < 0.05), with a mean correction of vertical deviation of 11.34 ± 2.71 PD and a mean correction of asymmetry of 2.5 ± 1.3 PD. Five patients needed inferior rectus retucking for residual manifest DVD.
Inferior rectus tucking is as effective as superior rectus recession with posterior fixation sutures for the primary treatment of DVD without inferior oblique overaction. Inferior rectus tucking can also be used effectively for the treatment of residual and recurrent DVD; further studies are recommended in this field.
Keywords: Inferior rectus tucking, superior rectus recession, posterior fixation (faden), dissociated vertical deviation
|How to cite this article:|
Diab MK. Inferior rectus tucking versus combined superior rectus recession with posterior fixation suture (faden) for the treatment of dissociated vertical deviation without inferior oblique overaction. J Egypt Ophthalmol Soc 2013;106:239-44
|How to cite this URL:|
Diab MK. Inferior rectus tucking versus combined superior rectus recession with posterior fixation suture (faden) for the treatment of dissociated vertical deviation without inferior oblique overaction. J Egypt Ophthalmol Soc [serial online] 2013 [cited 2017 Jun 24];106:239-44. Available from: http://www.jeos.eg.net/text.asp?2013/106/4/239/131573
| Introduction|| |
Dissociated vertical deviation (DVD) is an upward and extortional drift of the nonfixating eye. It occurs after the occlusion of one eye or spontaneously when an individual is fatigued or day dreaming . DVD is a poorly understood vertical deviation that may remain latent (compensated) or manifest (decompensated). The deviation, mostly bilateral, may be symmetrical or asymmetrical, small or large, alone or in combination with a true hypertropia, but is always intermittent . Steven  was the first in astonishment about the dissociated eye movement in 1890. Bielschowsky was the first to describe the term DVD in 1930 in the form of unilateral elevation, abduction, and extortion of a nonfixing eye. In 1976, Raab  described the slow unilateral abduction of the deviating eye as a horizontal variant of dissociated vertical divergence. When the cover is removed, the affected eye will move down without a corresponding down-drift of the other eye. Thus, DVD does not obey the Hering law of simultaneous innervations of the yolk muscles in both eyes . DVD is correlated highly with poor fusion (decreased use of the eyes binocularly); blurred image or double vision is usually not noticed when the eye drifts upward as the visual system suppresses the vision in the eye that drifts upward . Components of DVD include the following: dissociated elevation, dissociated abduction, dissociated extortion with latent nystagmus, and subnormal binocularity . Some authors have suggested that superior rectus is the hypertonic muscle in DVD ; few suggested weak depressors as the etiology .
Scobee  used the term 'double hyperphoria,' stating that either could be caused by paretic depressors, the superior oblique and inferior recti, and so overaction of the yoke muscles, the inferior oblique and superior rectus. Early surgical intervention for infantile esotropia enables binocularity and prevention of amblyopia, associated with a reduced incidence of the development of DVD . The goal of surgical treatment is to reduce the amplitude of DVD and to reduce the frequency of the manifest hyperdeviation, but full correction is seldom possible and surgery neither alters the basic defect nor eliminates DVD completely . Eye muscle surgery is usually indicated when the DVD is large and/or frequently present to the point that it becomes a cosmetic problem. Bilateral recession of the superior rectus muscle is the most common treatment modality used for correction of DVD . Posterior fixation suture is one of the main lines of treatment and the aim of the faden posterior suture is to shift the effective insertion of the superior rectus muscle posterior; thus, this theoretically reduces the effectiveness of the muscle in its field of action . The aim of our study is to compare the efficacy of two different surgical approaches in patients with DVD without inferior oblique overaction.
| Patients and methods|| |
This prospective study was carried out on patients with DVD without inferior oblique muscle overaction who attended the Outpatient Department of Magrabi Eye Hospital in Aseer region, KSA, from March 2008 to April 2013. A written consent was obtained from all patients or their parents before enrollment in the study and after an explanation was provided of the procedure to be performed and the possible outcomes. They were also informed about the need for repeated follow-up visits. This prospective study included 50 consecutive patients with DVD without inferior oblique overaction, who were distributed between two groups according to the surgical approach used for the treatment of DVD. Patients were distributed equally and randomly between the two groups according to their order of presentation. All surgeries were performed by the same surgeon (M.M.K.D). Inclusion criteria included cases with manifest bilateral DVD decompensated to a tropia with free ocular motility, without inferior oblique overaction and with or without horizontal misalignment. Of all the patients included in the study, only 19 patients had sole DVD, whereas 18 patients had DVD with exotropia and 13 patients had DVD with esotropia. Horizontal strabismus was present in 16 patients in group I and 15 patients in group II. Exclusion criteria included cases with compensated DVD, which remains as a phoria, incomitant paralytic, or restrictive strabismus, eyes with a history of previous muscle surgeries, any grade of bilateral or unilateral inferior oblique overaction, cases with vertical hypertropia of at least 10 prism diopter (PD) in one eye in primary position, recurrent DVD after surgical treatment, and eyes with previous scleral buckling for retinal detachment.
All patients were examined in the pediatric ophthalmology and orthoptic clinics for the corrected and uncorrected visual acuity, cover uncover and alternate cover tests, associated horizontal phoria or tropia, and ocular motility. The angle of strabismus was measured for distance and near with and without glasses using an alternate cover prisms test in the primary position and 30° side gaze, which was performed by rotating the face an estimated 30° and having the patient continuing to look forward. The diagnosis was confirmed by performing the reversed fixation test, which was devised by Kommerell and Mattheus , as a clinical technique to visualize the dissociated component in patients with dissociated vertical divergence. The reversed fixation test must be preceded by the prism and alternate cover test, which is used to neutralize the observed hyperdeviation of one eye. The reversed fixation test is then performed by instructing the patient to continue fixating through the prism with the hyperdeviated eye, and then shifting the occluder to again cover the prismatically neutralized eye. The eye without the prism is then observed for a downward refixation movement, which is considered to be indicative of dissociated vertical divergence. Binocular status of the patient was assessed by Bagolini striated glasses and Worth 4 dots test. The amount of DVD was graded from +1 to +4 according to Velez , who described a classification of DVD on the basis of the simultaneous prism and cover test: grade +1, up to 10 PD, grade +2: 11-15 PD, grade +3: 16-20 PD, and finally, grade +4 more than 20 PD [Table 1].
The patients in group I underwent bilateral superior rectus recession with posterior fixation sutures (faden procedure) using a hang-loose technique as described by Wright et al. . In this technique, the superior rectus was recessed using a double-armed 6-0 vicryl suture brought through the insertion, 'hanging back' the superior rectus for the desired number of millimeters. No scleral sutures were placed posterior to the intended point of muscle reinsertion. This allows recession of the superior rectus up to 16 mm while avoiding superior oblique dysfunction. For the muscle to retract freely, the intramuscular attachments to either side of the superior rectus must be cut well posteriorly. Special care must be taken during superior rectus surgery to avoid shearing off the anterior portion of the superior oblique insertion when removing the intramuscular septum. The grade of superior rectus recession was according to Velez  and Wright et al. . The faden procedure requires extreme posterior exposure. The posterior fixation suture is placed through the sclera 14 mm posterior to the original rectus muscle insertion. A nonabsorbable 5-0 Mersilene suture on a spatula needle was used in order to help avoid scleral perforation. One patient with pure unilateral DVD with deep amblyopia was subjected to unilateral surgery on the hypertropic amblyopic eye only. In these cases, the amount of recession of the superior rectus is less than 9 mm to prevent hypotropia of the amblyopic eye. The patients in group II were treated with bilateral inferior rectus tucking (plication), according to Salama et al. , who used double-armed polyglactin 910 vicryl 6/0 sutures through a fornix-based conjunctival incision with proper dissection of Tenons' capsule and intramuscular septum and the tucked muscles were fixed to the sclera at the edge of inferior oblique insertion. Inferior rectus tucking ranged from 4 to 7 mm according to the grade of DVD. Recession of superior rectus or tucking of inferior rectus was either symmetrical or asymmetrical according to the degree and symmetry of DVD in both eyes of each patient.
Postoperatively, all patients were examined regularly in the orthoptic clinic in the same preoperative manner by the same investigator every two weeks for a follow-up period of at least 9 months (9-12 months) to assess the surgical outcome, to evaluate both vertical and horizontal alignment, and to measure the degree of any residual DVD. These data were reported at 1, 3, and 9 months after surgery. In both groups, postoperative residual DVD grade +3 in both eyes or +3 in one eye and +2 in the other eye were retreated with bilateral surgical correction, whereas residual DVD grade +3 in one eye and +1 in other eye was retreated with unilateral surgical correction after 3 months [Table 2].
|Table 2: Amount of bilateral superior rectus recession in different grades of DVD [1,17]|
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Statistical analyses were carried out and quantitative data were reported as mean±SD using SPSS, version 15 (SPSS Inc., Chicago, Illinois, USA). A paired t-test was used to compare the angle of deviation before and after surgical correction of one group. The c2 -test was used to compare and determine a statistically significant difference in the preoperative and the postoperative angle of DVD between the two groups. A P value of 0.05 or less was considered significant.
| Results|| |
The study included 50 patients with DVD and with no inferior oblique overaction. They were allocated equally and randomly between the two groups in their order of presentation. Group I included 25 patients, 14 men and 11 women, mean age 29.4 ± 7.8 years, whereas group II included 25 patients, 17 men and eight women, mean age 30.5 ± 9.1years. [Table 3] shows the grades of DVD of each of the 50 patients before and after surgery at 3 months and at the 9-month follow-up.
|Table 3: The mean preoperative and postoperative deviation in both groups|
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The preoperative mean angle of deviation was 18.21 ± 4.73 PD in group I and 17.97 ± 6.89 PD in group II. The mean grades of DVD had improved significantly after surgery, with no statistical significance in the two groups (P < 0.05) with variable percentage. The postoperative mean angle of deviation improved to 7.82 ± 5.61 PD in group I and to 6.97 ± 5.46 PD in group II. The mean correction of vertical deviation and the mean correction of asymmetry in the two groups were 10.21 ± 3.52 PD and 2.1 ± 1.6 PD in group I (P < 0.05), whereas they were 11.34 ± 2.71 PD and 2.5 ± 1.3 PD in group II [Table 3], with no significant difference between both groups (P > 0.05).
In group I, the mean amount of vertical correction achieved by posterior fixation sutures with recession of superior rectus muscle was 3.42 ± 0.73 PD per 1 mm, whereas the mean amount of vertical correction achieved by tucking of inferior rectus muscles was 2.91 ± 0.69 PD per 1 mm in group II. Associated horizontal strabismus was found in 31 of 50 patients. Horizontal muscles surgeries corrected the horizontal angle to less than 10 PD in the primary position in 25 patients, whereas six patients showed a persistent postoperative horizontal angle of more than 10 PD: four patients in group I and two patients in group II. They were subjected to reoperation in the same session of residual DVD.
Preoperative and postoperative grades of DVD [Table 4] in group I showed nine (36%) patients with +4 DVD bilaterally, seven (28%) patients with +4 in one eye and +3 in other eye, three (12%) patients with +3 DVD bilaterally, five (20%) patients with variable grade between +2 and +3 in both eyes, and finally, one patient with amblyopia had +3 grade in one eye and +1 grade in the other eye. Twenty-one (84%) patients showed a variable degree of improvement graded between +2 and 0 in the follow-up after 3 months. Our results indicated corrected 10.21 ± 3.52 PD of vertical deviation and 2.1 ± 1.6 PD of asymmetry. Two (8%) patients revealed postoperatively within the first 3 months; one eye showed +3 grade in the more affected eye and +2 grade in the other eye. One patient (4%) had +2 grade one eye and +1 grade in the other eye in the first week postoperatively and progressively relapsed to +3 grade in one eye and +2 grade in the other eye within three months. In one patient (4%), postoperatively, the right eye showed +3 grade and the left eye showed +1 grade ; all these four (16%) patients were subjected to resurgical correction of DVD after 3 months by bilateral inferior rectus tucking in three patients and the fourth patient was treated by unilateral right inferior rectus tucking.
Grades of DVD in group II indicated that preoperatively, eight (32%) patients had +4 DVD bilaterally and eight (32%) patients had +4 grade in one eye and +3 grade in the other eye, five (20%) patients were +3 DVD bilaterally, and finally, four (16%) patients showed variable grade between +2 and +3 in both eyes. This procedure corrected 11.34 ± 2.71 PD of vertical deviation and 2.5 ± 1.3 PD of asymmetry. Twenty (80%) postoperative cases showed variable degree of improvement in DVD between +2 and 0 grade, only five (20%) patients in group II showed just a mild improvement in the DVD grade postoperatively, four patients from +3 to +2, and in only one patient (4%), postoperatively, one eye showed +3 grade in the left eye and +1 grade in the right eye; resurgical correction by the bilateral inferior rectus retucking technique was performed for four patients and the fifth patient was subjected to unilateral left inferior rectus retucking.
| Discussion|| |
It has been proposed that DVD is unmasking of a dorsal light reflex with disruption of normal binocular development. Asymmetrical visual input to both eyes induces intermittent and alternate excitation of both subcortical centers that govern the vertical divergence movement of the eyes. The fixating eye maintains its position unchanged because voluntary innervation of the depressors neutralizes the innervations to the elevators .
According to Helveston , the earlier in life the fusion anomaly occurs, the more likely that DVD may occur and persist. The earlier the disruption of binocular cooperation, the less likely the patient will be able to reestablish it. Thus, improper fusion development could be an important factor in the association of DVD with sensory visual deprivations. According to Bielschowsky , the only means of reducing the onset of these deviations and maintaining it latent is by improving the fusional innervations mechanism. DVD manifests at times of fatigue, inattention, or when binocular visual input is mechanically and optically pre-empted .
Most of the previous literatures  considered DVD as a bilateral disease although it is asymmetrical. For this, surgical treatment is initiated bilaterally and asymmetrically, and this is in agreement with our study, except for one patient in group I with unilateral DVD and deep amblyopia, who was treated with unilateral SR recession less than 9 mm with posterior fixation sutures to avoid hypotropia in the amblyopic eye.
The decision to perform combined superior rectus muscle recession using the Faden procedure was hanging on to strong elevators for the postulated reason . However, the choice favoring inferior rectus muscle surgery over superior rectus recession was governed by the theory that weak depressors are the main cause rather than strong elevators . This study compared two treatment modalities that depend on both philosophies.
According to Wright , several treatments for DVD have been attempted, including the following:
- A combination of standard superior rectus recession and the Faden procedure,
- Sole recession of the superior rectus,
- Faden or posterior fixation suture of the superior rectus, and
- Resection of the inferior rectus muscle.
Few earlier studies  have investigated inferior rectus strengthening for the management of DVD, utilizing resection not tucking, and all involved patients who had undergone previous eye muscle surgery, either for residual DVD after failed superior rectus recession, or included patients with consecutive DVD after horizontal muscle surgery. Interestingly, in this study, we used inferior rectus tucking as a primary line of treatment in group II.
Knapp  combined standard recession of the superior rectus with resection of the inferior rectus and reported good results that were not in agreement with our results as we achieved a good result using sole inferior rectus tucking or combined superior rectus recession with posterior fixation Faden sutures.
Most of the previous studies showed that complete control and disappearance of the DVD is difficult and occurs only in a minority of patients, and a satisfactory good result in DVD treatment is achieved when the deviation is controlled, even though it is not eliminated completely, and in agreement with the results of our study .
When DVD and inferior oblique muscle overaction coexist, anterior transposition of the inferior oblique muscle has been used to treat DVD up to about 15 PD ,,; this line of treatment is only suitable for cases associated with inferior oblique muscle overaction. Thus, its anterlization allows management of both DVD and inferior oblique overaction ,. This result is not in agreement with our study as we did not use inferior oblique surgery because patients with inferior oblique overaction were excluded.
Few previous authors have used inferior rectus strengthening for the management of DVD; however, most of them proceeded with resection not tucking and all were restricted only to patients who had undergone previous eye muscle surgery, for residual DVD after failed superior rectus recession, or in patients with consecutive DVD after horizontal muscle surgery , in disagreement with our study, as we used inferior rectus tucking and not resection as the primary treatment in group II.
To the best of our knowledge, only one previous study used inferior rectus tucking as the primary treatment, Salama et al. , but they applied a narrow scale with few numbers of patients, only seven patients, and they did not use any other line of treatment.
Our results of combined faden and recession in a group are in agreement with those of Lorenz et al.  and Kii et al. , who reported that the faden operation must be combined with a recession of the superior rectus muscle of at least 3 mm to avoid undercorrections if the original angle of deviation is larger than 14 prism.
Some patients in preceding researches who had undergone inferior rectus resection unfortunately showed narrowing of the palpebral fissure , but in our study, this complication was not encountered, which may have been because of proper wide dissection of intramuscular connective tissue septa, in addition to the fact that we used just tucking technique substitution to resection.
Most authors  considered DVD a bilateral disease, but it may be asymmetrical as bilateral surgical correction was indicated in concurrence with our procedure in both groups; we preferred performing bilateral surgery throughout the research in the two groups, except in one patient with amblyopia in group one with pure unilateral DVD.
Can et al.  and Sprague et al.  reported that some patients developed a cosmetically unacceptable moderate or large DVD in the eye that had a very small DVD before surgery after performing sole posterior fixation suture; thus, this unproductive line of treatment was not considered in our study.
In our study, residual DVD was present in four patients in group I and in five patients in group II, and was treated by inferior rectus tucking in group I and retucking in group II, which is not in agreement with other researchers, who prescribed inferior rectus resection as the proper management for residual DVD .
The best results (P = 0.021) of Esswein et al.  were achieved with 7-9 mm recessions with posterior fixation sutures compared with sole superior rectus muscle recessions in 228 patients with DVD, in agreement with our results in group I.
| Conclusion|| |
Inferior rectus tucking is as effective as superior rectus recession with posterior fixation sutures for the primary treatment of DVD without inferior oblique overaction. Inferior rectus tucking could also be used effectively for the treatment of residual and recurrent DVD; further studies are recommended in this field.
| Acknowledgements|| |
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]