Vertical Muscle Surgery Research Articles

Efficacy of Vertical Muscle Transpositions with and without Simultaneous Rectus Muscle Recession for Unilateral Sixth Nerve Palsy

We report results of a modified vertical muscle transposition procedure according to the Hummelsheim principle - with and without simultaneous rectus muscle recession - for unilateral sixth nerve palsy. We examine the influence of the duration of the palsy, preoperative angle of squint and preoperative abductive capacity on surgical results of the procedures. Retrospective study of 29 consecutive patients with unilateral abducens nerve palsy who underwent surgery between 2001 and 2012. 21 patients had a modified vertical rectus muscle transposition according to the Hummelsheim principle (HUM); 8 patients had this operation combined with simultaneous medial rectus muscle recession (HUM+I). Surgery was performed at least 9 months after onset of the palsy (HUM: 9 to 98, median 19, mean 30months; HUM+I: 12 to 65, median 25, mean 29 months). The median preoperative angle of squint (far distance) for the HUM group was 27.0° (20.0 to 45.0; mean 28.1°), and for the HUM+I group 30.5° (21.8 to 50.0; mean 33.4°). The median preoperative abductive capacity was for - 1,6 mm before midline (- 8.0 to + 1.2; mean - 1.8 mm) for the HUM group, and - 3.0 mm before midline (- 10.0 to - 1.0; mean - 4.1 mm) for the HUM+I group. The median postoperative angle of squint (far distance) was 0° (- 11.3 to + 20.0; mean 0.1°) for the HUM group, and - 2.3° (- 11.3 to + 12.0; mean - 2.1°) for the HUM+I group. The median postoperative abductive capacity was 1.0 mm (0 to + 3.0; mean + 1.1 mm) for the HUM group, and 1.1 mm (- 1.2 to + 3.0; mean + 0.9 mm) for the HUM+I group. The median reduction of squint angle was 27.0° (9.1 to 45.0; mean 28.0°) for the HUM group, and 36.8° (25.2 to 41.4; mean 35.5°) for the HUM+I group. The median effect on abductive capacity was 2.5 mm (0 to 11.0; mean + 2.9 mm) for the HUM group, and 4.6 mm (2.4 to 8.8; mean + 5.0 mm) for the HUM+I group. In the HUM group, the effect on squint angle reduced with the duration of the palsy, whereas, in the HUM+I group, the effect improved with the duration of the palsy. For patients with unilateral sixth nerve palsy, simultaneous medial rectus recession increases the effect of modified vertical rectus muscle surgery according to the Hummelsheim principle. The duration of the palsy is a relevant parameter for the selection of a sole or combined intervention with medial rectus recession.

Immediate postoperative alignment measurements as a predictor of alignment stability in fixed suture strabismus surgery

Purpose To evaluate the use of immediate postoperative alignment measurements as a predictor of future alignment stability in fixed suture strabismus surgery. Methods Forty-seven patients were prospectively evaluated after undergoing horizontal or vertical rectus muscle surgery using a fixed suture technique. Alignment measurements were taken approximately 1 hour, 1 to 3 weeks, and 2 to 3 months postoperatively. A Spearman correlation coefficient was used to compare measurements from the immediate postoperative period to the 2- to 3-month postoperative period. Patients with dissociated strabismus, only oblique muscle surgery, or poor vision in one or both eyes precluding precise alternate cover test were excluded. Results Mean age of all patients was 46.7 years (range: 12 to 86 years). Twenty-two patients underwent surgery for exotropia: 19 for esotropia and 6 for hypertropia. Mean alignment for all surgeries was 2 prism diopters (PD) undercorrection in the immediate postoperative period, which was similar to the mean of 4.6 PD undercorrection at 2 to 3 months postoperatively. However, the Spearman correlation between the immediate postoperative and 2- to 3-month postoperative measurements was 0.18 for all surgeries, 0.03 for exotropia, 0.56 for esotropia, and 0.40 for hypertropia. The overall success rate, defined as 8 PD or less of horizontal deviation and 4 PD or less of vertical deviation, was 77% at 2 to 3 months postoperatively. Conclusions The relationship between immediate postoperative alignment and future alignment stability in fixed suture strabismus surgery has not been previously defined. The current study demonstrated that although the surgical success rate was reasonably good, poor correlation occurred between the alignment immediately postoperatively and 2 to 3 months postoperatively. [J Pediatr Ophthalmol Strabismus. 2018;55(4):240-244.].

To assess the efficacy of vertical muscle surgery for management of hypotropia in monocular elevation deficiency type II.

To assess the efficacy of vertical muscle surgery for management of hypotropia in monocular elevation deficiency (MED) type II. Knapp's is described as standard procedure for management of MED type II. However, it is not graded and has unpredictable amount of correction. Besides this, there is drift towards overcorrection with time and limitation of movements in extreme adduction and abduction. MED is a vertical misalignment for which vertical muscle surgery is also described but limited literature is available. Thirteen fresh cases of MED type II with hypotropia >20PD and age >4years were included in our interventional study. All cases underwent superior rectus resection and inferior rectus recession (vertical R&R) depending upon amount of preoperative deviation. Success was defined as hypotropia <5PD at 1-year follow-up. Twelve patients (92.30%) were aligned to within 5PD. Six patients (46.15%) had gain in elevation. Bell's phenomenon was improved in six patients (46.15%). There was no limitation in down gaze in any patient. None gained stereopsis. Vertical R&R is a good alternative for MED type II with predictable amount of correction especially in patients with higher preoperative deviation. It spares horizontal muscles for correction of any associated horizontal deviation.

Strabismus surgery among Medicare beneficiaries: imputed rates of reoperation in the same calendar year.

To compare strabismus surgery reoperation rates in a large national database of provider payments when the adjustable-suture technique was available and not available. Fee-for-service payments to Medicare providers for horizontal (CPT 67311) and vertical (CPT 67314) strabismus surgery in 2012 were analyzed to identify payments for reoperations in the same calendar year. The adjustable-suture technique was considered to be available to the patient if the patient's surgeon billed for adjustable sutures during the year. We determined the association of reoperation with the availability of the adjustable-suture technique and with surgeon volume. Patients having horizontal muscle surgery had a rate of reoperation in 2012 of 4.1% (15 of 364 patients) when the adjustable technique was available, compared with 7.1% (77 of 1,082 patients) when the adjustable technique was not available (P = 0.047). Patients having vertical muscle surgery had a rate of reoperation in 2012 of 4.1% (8 of 196 patients) when the adjustable technique was available, compared with 8.3% (38 of 458 patients) when the adjustable technique was not available (P = 0.07). Having surgery in a high-volume surgical practice was not reliably associated with reoperation rates. For patients having strabismus surgery, the availability of the adjustable-suture technique was associated with a lower reoperation rate in this large national database (compared with patients for whom the adjustable technique was not available). The difference was statistically significantly different from zero for horizontal muscle surgery but not for vertical muscle surgery.

Predictability of horizontal versus vertical muscle surgery outcomes in thyroid eye disease.

Surgical repair of vertical muscles in thyroid eye disease (TED) is believed to yield more unpredictable results than horizontal muscle surgery. The purpose of this study is to determine if the short-term outcomes for strabismus surgery in TED are equally predictable for horizontal and vertical muscle surgery. We retrospectively reviewed the charts of 27 consecutive patients who underwent strabismus surgery for TED from a single surgeon's practice. Eligibility for inclusion in the study included biochemically stable thyroid disease for at least a year and stable orthoptic measurements for at least 6months prior to surgery. Nine patients had surgery only on vertical rectus muscles, three only on horizontal, and fifteen on both vertical and horizontal rectus muscles. Mean follow-up was 2.4±5.2months. In primary gaze at 6m, a mean horizontal deviation of 16.6±22.3 PD, and a mean vertical deviation of 19.7±14.1 PD were measured pre-operatively. Post-operatively, this measured 2.3±8.4 PD horizontally and 2.1±7.8 PD vertically (p=0.933). There was no statistically significant difference between post-operative horizontal and vertical deviations in elevation, depression, adduction, and abduction. Nine patients required reoperation to attain satisfactory ocular alignment; seven of these cases involved repeat surgery on vertical muscles, while two cases required operation on both horizontal and vertical muscles. Results suggest that surgical outcomes of both horizontal and vertical muscle surgery are equally predictable in stable TED; however, reoperation rates were higher for vertical muscles compared to horizontal muscles.

Surgery for Supranuclear Monocular Elevation Deficiency

Purpose: We report a novel approach to surgery for monocular elevation deficiency (MED).Methods: A retrospective review of 5 patients undergoing surgery for supranuclear MED between 2003 and 2014. All patients had intact Bell’s phenomenon, hypotropia, limited elevation above the primary position, and negative forced duction testing of the paretic eye. Preoperatively all patients preferred chin-up head posture and three had pseudoptosis or ptosis. One of the 5 had prior vertical muscle surgery. Surgery correction for the MED consisted of near maximal superior rectus recession on the contralateral sound eye.Results: Compensatory chin-up head position and alignment in primary position was improved in all patients. Average age at surgery was 5.3 years. Average superior rectus recession was 9.7 mm. Mean follow-up was 4.8 years (range 12 months to 11.5 years). The vertical deviation of the paretic eye in primary position postoperatively was orthotropic for 2, hypotropic for 2, and overcorrected for 1.Conclusions: In cases of supranuclear MED (double elevator palsy) contralateral superior rectus recession based on the innervational principle is a simple and reliable alternative surgical approach compared to published results of the Knapp transposition procedure. Additionally, it holds the possibility for decreased complications and less complicated future surgical treatment options.

Strabismus Surgery Reoperation Rates With Adjustable and Conventional Sutures

To determine the association of strabismus surgery reoperation rates with adjustable or conventional sutures. Retrospective cross-sectional study. setting: Review of a large national private insurance database. Adults aged 18-89 having strabismus surgery between 2007 and 2011. Adjustable vs conventional suture strabismus surgery. Reoperation rate in the first postoperative year. Overall, 526 of 6178 surgical patients had a reoperation (8.5%). Reoperations were performed after 8.1% of adjustable suture surgeries and after 8.6% of conventional suture surgeries (P = .57). Of the 4357 horizontal muscle surgeries, reoperations were performed after 5.8% of adjustable suture surgeries, and after 7.8% of conventional suture surgeries (P = .02). Of the 1072 vertical muscle surgeries, reoperations were performed after 15.2% of adjustable suture surgeries and after 10.4% of conventional suture surgeries (P = .05). Younger age (18-39 years) was associated with a lower reoperation rate (P ≤ .02). The significant multivariable predictors of reoperation for horizontal surgery were adjustable sutures (odds ratio [OR] 0.69, 95% confidence interval 0.52-0.91), monocular deviation (OR 0.64), complex surgery (OR 1.63), and unilateral surgery on 2 horizontal muscles (OR 0.70, all P ≤ .01). Adjustable sutures were not significantly associated with reoperation rates after vertical muscle surgery (multivariable OR 1.45, P = .07). Adjustable sutures were associated with significantly fewer reoperations for horizontal muscle surgery. Adjustable sutures tended to be associated with more reoperations for vertical muscle surgery, but this observation was not statistically significant in the primary analysis after controlling for age.

Correction of Hypertropia Coexisting with Intermittent Exotropia

Purpose: To investigate the clinical features associated with hypertropia and report the surgical outcomes of hypertropia coexisting with exotropia. Methods: We reviewed the medical records of 148 patients with intermittent exotropia coexisting with hypertropia over 4 PD who received exotropia surgery. The cases accompanied by apparent paralytic strabismus such as superior oblique palsy were excluded. Patients were divided into groupI(clinically diagnosed hypertropia) and group II (non-specific hypertropia) and the clinical features of coexisting hypertropia and surgical outcomes were analyzed. Results: Among the 148 patients, groupIconsisted of 38 patients (26%) and group II of 110 patients (74%). The average amount of preoperative hypertropia angle in primary gaze was 9.58 ± 3.89 PD and 6.62 ± 2.69 PD in group I and II, respectively. Group I included 12 patients with dissociated vertical deviation (DVD), 10 patients with unilateral inferior oblique overaction, 13 patients with asymmetric bilateral inferior oblique overaction and 3 patients with superior oblique overaction. Group II included 19 patients with comitant hypertropia (17%), head tilt positive pattern (simulated superior oblique palsy) was found in 84 patients (76.3%) and variable incomitance was observed. In groupI, 29 patients received simultaneous horizontal muscle with hypertropia surgery. Postoperative hypertropia angle in groupI was 1.41 ± 2.93 PD and 4 cases were considered surgical failure. In groupII, hypertropia was resolved with horizontal muscle surgery only and the amount of postoperative hypertropia was 0.45 ± 1.60 PD. Conclusions: In this study, vertical deviations in intermittent exotropia with concomitant hypertropia related to obvious oblique muscle dysfunction or DVD were corrected effectively by oblique or vertical rectus muscle surgery. Nonspecific hypertropia can be resolved after horizontal muscle surgery alone, however, for precise differential diagnosis, careful examination for variable clinical features is necessary before determining surgery. J Korean Ophthalmol Soc 2014;55(12):1883-1889

Erratum to: Effects of vertical muscle surgery on differences in the orientation of Listing’s plane in patients with superior oblique palsy

Erratum to: Effects of vertical muscle surgery on differences in the orientation of Listing’s plane in patients with superior oblique palsy

Surgical outcomes of symmetric and asymmetric surgery for intermittent exotropia with postoperative large early overcorrection

To compare surgical outcomes between bilateral lateral rectus recession (BLR) and unilateral lateral rectus recession-medial rectus resection (RR) for intermittent exotropia with overcorrection of 20 prism diopter (PD) or more on postoperative day 1. A retrospective chart review identified 319 patients who underwent either BLR or RR for primary surgical treatment of intermittent exotropia between July 2008 and June 2011. The patients with basic type intermittent exotropia and overcorrection of 20 PD or more, at either near or distance, on postoperative day 1 and had more than 6 months of follow-up were included. Patients with simultaneous vertical and/or oblique muscle surgery and those with paralytic or restrictive strabismus were excluded. The pre- and post-operative deviation, visual acuity, and near stereoacuity were analyzed. Twenty-four patients were included. The mean postoperative day 1 alignment was 21.5 ± 6.2 PD esotropia at distance, and 13.8 ± 8.0 PD at near. Fourteen patients underwent BLR and 10 underwent RR. Three patients were wearing the base out prism below 15 PD at the last follow-up. The mean duration from the surgery to esotropia below 10 PD was 2.9 ± 1.1 weeks and 8.0 ± 7.1 weeks in the BLR and RR groups, respectively (p = 0.030). All three recurrent patients underwent RR. None of the patients completely lost stereoacuity, postoperatively. In basic type intermittent exotropia with overcorrection of 20 PD or more on postoperative day 1, the overcorrection resolved faster and recurrence rates were lower in BLR group than in the RR group. Consecutive esotropia over 15 PD did not occur in both groups.

Effects of vertical muscle surgery on differences in the orientation of Listing’s plane in patients with superior oblique palsy

Although scleral search coils are widely and accurately used for the measurement of Listing's plane in both eyes, they require specialized equipment and are invasive. In this study, we describe a convenient and less invasive method that uses a synoptometer to analyze the differences in orientation of Listing's plane (difLP), and the effects of vertical muscle surgery on the difLP tilt in patients with superior oblique palsy (SOP). Seventeen patients with unilateral congenital SOP (CSOP) and four patients with unilateral acquired SOP (ASOP) who had not undergone any strabismus surgeries were examined. Cyclodeviations of 13 vertical and horizontal gaze points within 30° were measured with a synoptometer, and the difLP tilts in the yaw and pitch planes were analyzed before and after vertical muscle surgery. The difLP tilt in the CSOP patients was significantly tilted nasally (p = 0.02) and forward on the lower side (p = 0.001), whereas that in ASOP patients tended to tilt temporally (p = 0.15). Ipsilateral inferior oblique recession (IOR) performed in seven CSOP patients tended to improve the difLP tilt in both the yaw (p = 0.07) and pitch (p = 0.09) planes, whereas contralateral inferior rectus recession (IRR) performed in three CSOP patients significantly improved the difLP tilt in the pitch plane (p = 0.015). The mean excyclodeviations in the 13 gaze points were significantly improved with both procedures (p < 0.0001 for both). The difLP tilt in the SOP patients could be analyzed with a convenient and less invasive method using a synoptometer, and dissimilar difLP tilts were confirmed in the ASOP and CSOP patients. The results of this study suggest that both IOR and IRR are reasonable treatments for improving the difLP tilt in CSOP patients. IOR should be selected for patients with a steep preoperative difLP tilt to the nasal side, whereas IRR should be selected for patients with a gentle preoperative difLP tilt.

Comparison of inferior oblique myectomy to recession for the treatment of superior oblique palsy

PurposeTo compare inferior oblique (IO) myectomy with recession for the treatment of superior oblique (SO) palsy.MethodsA retrospective review of medical records identified all patients with SO palsy who underwent IO...

Partial third cranial nerve palsy: clinical characteristics and surgical management

PurposeIncomplete recovery from injury to the third cranial nerve results in ocular misalignment and associated diplopia. Our aim in this study was to describe and evaluate strabismus surgery strategies aimed at restoring functional, single binocular vision in this population. DesignRetrospective review. ParticipantsWe studied 12 adult patients with acquired partial third cranial nerve palsy who underwent strabismus surgery. MethodsThe 12 consecutive patients with residual third nerve palsy were selected from among the patients seen between 2000 and 2010 in the clinical practice of 1 strabismologist (M.F.). Complete pre- and postoperative ophthalmologic and orthoptic examinations were performed in each patient. The patients presented with isolated hypotropias (n = 7) and exohypotropias (n = 5). Strabismus surgery included: contralateral superior rectus recession, ipsilateral inferior rectus recession, vertical transposition of horizontal recti, horizontal rectus muscle surgery, or combined horizontal and vertical muscle surgery. Complete surgical success was defined as postoperative alignment within 5 prism diopters (PD) of orthotropia and the absence of diplopia in functional positions of gaze. The average follow-up was 23 months (range, 7 to 81 months). ResultsThe mean preoperative vertical and horizontal deviations were 19 PD hypotropia (8–40 PD) and 19 PD exotropia (6–40 PD), respectively. The mean postoperative deviations were 2 PD hypotropia (0–8 PD) and 1 PD exotropia (0–6 PD). Complete surgical success was achieved in 7 of 12 patients. Partial success was attained in 5 of 12 patients, who experienced significant improvement but required postoperative use of a prism. ConclusionsThis study indicates that patients with incomplete third cranial nerve paralysis may enjoy good functional and cosmetic outcomes with strabismus surgery.

Localising rectus muscle insertions using high frequency wide-field ultrasound biomicroscopy

AimThe ultrasound biomicroscope (UBM) can accurately locate an extraocular muscle (EOM) insertion. The authors compared the accuracy of the Sonomed UBM (SUBM), a new ‘wide-field ultrasound biomicroscope’, with the older...

Surgical management of clinically significant hypertropia associated with exotropia

To report the surgical treatment of hypertropia coexisting with exotropia, with either vertical offset surgery or additional vertical muscle surgery simultaneous to correction of the exotropia. A total of 35 patients with exotropia and hypertropia who underwent a horizontal muscle surgery for exotropia were included. To determine efficacy in resolving a vertical deviation in patients with exotropia, 28 patients were compared in 2 groups: those who underwent horizontal muscle surgery with vertical offset and those who underwent horizontal muscle surgery with additional vertical muscle surgery. An additional 7 patients who had exotropia and hypertropia but did not undergo vertically corrective surgery were included for comparison. Vertical offset of horizontal rectus muscles (4 mm) resulted in 8(Delta) correction of the distance hypertropia. Vertical rectus muscle recession used in the treatment of larger hypertropic deviations with exotropia had a 3(Delta) correction per 1 mm of recession. Success rates for hypertropia correction were similar between groups, 63% vertical offset and 71% vertical muscle groups; overcorrections occurred in 29% of the vertical muscle group. The vertical correction in both groups was stable in 88% over 6 months postoperatively. Vertical offset of the horizontal muscles simultaneous with exotropia correction has a beneficial effect in small-angle hypertropia (<14(Delta)). Vertical rectus muscle surgery in patients with hypertropia greater than 10(Delta) had equivalent success; however, in intermittent exotropia the hypertropia was prone to overcorrection.

021: Surgical management of clinically significant hypertropia associated with exotropia

Introduction: Vertical muscle deviations often coexist with basic horizontal muscle deviations. Previous studies have focused on separate horizontal rectus and vertical rectus muscle surgery (deviations >15Δ) or horizontal muscle transposition surgery alone to effectively resolve a vertical deviation. The purpose of this study is to determine whether horizontal muscle surgery with transposition or additional vertical muscle surgery is most effective in resolving a vertical deviation in patients with exotropia. Additionally, to determine the measurement for incorporating a vertical muscle surgery to an exotropic surgery improve its overall effect.

Binocular Vertical Rectus Muscle Recession For Comitant Vertical Strabismus

Binocular vertical rectus muscle recession has not been formally evaluated in the correction of comitant vertical strabismus. Eight patients with stable comitant vertical strabismus for at least 6 months were included. All underwent recession of the superior rectus muscle of the hypertropic eye combined with an equal or nearly equal recession of the inferior rectus muscle in the hypotropic eye. On the day before surgery, on one of the first three postoperative days, and at one year postoperatively, ocular alignment in vertical and horizontal gaze directions were measured with simultaneous and alternate cover test at a viewing distance of 5 meters, and with the two dimensional Hess screen test. The field of single binocular vision was determined with a Goldmann perimeter. The Lang stereopsis chart was presented at the last follow-up visit. All patients were orthotropic at the last postoperative follow-up visit. In primary gaze, the degree of vertical and horizontal phoria diminished significantly. Normal alignment was achieved in nearly all gaze directions and stereopsis was reestablished. The field of single binocular vision enlarged after the surgery. Binocular vertical rectus muscle recession is an effective surgical approach for patients with comitant vertical ocular misalignment.

Combined Eyelid and Strabismus Surgery: Examining Conventional Surgical Wisdom

To determine whether satisfactory results of both eyelid surgery and strabismus surgery can be obtained when these procedures are performed in the same setting in selected patients. Nine patients (16 eyelids) who had undergone surgery in the same setting for eyelid malposition and strabismus of the horizontal rectus muscles, with or without concurrent vertical rectus muscle surgery, were retrospectively reviewed. Eyelid malposition surgery success was defined as a postoperative margin reflex distance (MRD1) within 1 mm of the target. Strabismus surgery success was defined as a postoperative deviation within 8 prism diopters of orthophoria or a decrease in binocular diplopia if the patient had a less than 8 prism diopters deviation in primary gaze preoperatively. Eyelid retraction repair was performed on 13 upper eyelids, levator advancement was performed on 2 eyelids, and frontalis suspension was performed on 1 eyelid. Four patients underwent bilateral medial rectus recession and the remaining 5 patients received varying strabismus surgery. Four patients received adjustable sutures. Mean follow-up was 11 months. Postoperatively, 13 of 16 eyelids (81%) achieved an MRD1 within 1 mm of the target. Eight of 9 patients (89%) demonstrated satisfactory strabismus correction. Combined eyelid malposition and strabismus surgery can be successfully performed in selected cases, particularly when the strabismus surgery involves the horizontal rectus muscles. Combined surgery is not recommended in cases that do not involve the horizontal rectus muscles.

Binocular responses and vertical strabismus

Elevation in adduction is the most common pattern of vertical strabismus, and it is mostly treated with surgery. The results of weaking of inferior oblique muscle are very changeable. The aim of this study was to evaluate binocular vision using sensory tests before and one and six months after the surgery. A total of 79 children were divided in two groups: the first, with inferior oblique muscle of overaction (n = 52), and the second with dissociated vertical deviation (DVD), and primary inferior oblique muscle overaction (n = 27). We tested them by polaroid mirror test (PMT), Worth test at distance and near, fusion amplitudes on sinoptofore, Lang I stereo test and Wirt-Titmus stereo test. We examined our patients before and two times after the surgery for vertical strabismus. Foveal suppression in the group I was found in 60.5% of the patients before, and in 56.4% after the surgery. In group II Foveal suppression was detected in 64.7% of the patients before, but in 55.6% 6 months after the surgery with PMT. Worth test revealed suppression in 23.5% of the patients before, and in 40.7% after the vertical muscle surgery. Parafoveal fussion persisted in about 1/3 of the patients before the surgery, and their amplitudes were a little largen after the surgery in the group I patients. Lang I stereo test was negative in 53.9% before and 51.9% after the surgery in the group I, and in 48.2% of the patients before and after the surgery in the group II patients. Wirt-Titmus stereo test was negative in 74.5% of the patients before and in 72.9% after the surgery in the group I, but in the group II it was negative in 70.8% before and in 68.0% of the patients 6 months after the surgery. Binocular responses were found after surgury in 65.7% of the patients the group I and in 55.6% patients the group II. There was no significant difference between these two groups, but binocular responses were more often in the patients of the group I.

Vertical Deviations Improved With Release of Postoperative Inferior Oblique Muscle Inclusion

In repeat surgery involving the horizontal extraocular muscles, it is frequently noted that the anterior fibers of the inferior oblique muscle are inadvertently caught in the lateral rectus muscle insertion. It is theorized that releasing the IO muscle inclusion (IOI) will decrease the total amount of vertical deviation associated with the horizontal misalignment in primary position. The current study shows the impact of this release on the vertical deviation. A retrospective noncomparative analysis was used to evaluate the impact of eliminating the IOI. The subjects were 45 patients with residual horizontal strabismus found to have IOI at the time of surgery. Each patient was managed with release of the entrapped muscle along with the appropriate horizontal muscle surgery. Release of the IOI muscle reduced the ipsilateral vertical deviation an average of 3.5 PD ( P > 0.001) in cases of hypotropia and 5.8 PD ( P > 0.001) in patients with hypertropia, with stability of alignment for a minimum of 2 years. Inadvertent IOI is commonly encountered in reoperative strabismus for horizontal deviations, involving partial or complete capture of the IO muscle fibers at the time of original lateral rectus muscle surgery. It is concluded that the simple release of the IO muscle fibers included in the attachment of the lateral rectus muscle will have a significant impact on reducing the vertical deviation and may avoid the need for additional vertical muscle surgery.