Importance of sagittal orbital imaging in evaluating extraocular muscle trauma following endoscopic sinus surgery.

BACKGROUND/AIMS: Orbital trauma may result in severe restrictive, paralytic, or combined strabismus. Clinical diagnosis may be extremely challenging. Orbital imaging is helpful in determining the exact site of injury, functionality, and integrity of the extraocular muscles. A typical study now includes coronal and axial views of the muscles. This study aimed to emphasise the importance of sagittal imaging of the orbit when evaluating extraocular muscle injury or entrapment. METHODS: A retrospective review of two subjects who underwent endoscopic sinus surgery procedures that resulted in trauma to the medial rectus muscle. High resolution orbital imaging studies were performed. RESULTS: High resolution magnetic resonance imaging (MRI) scans with coronal and axial views suggested a large section of the muscle was not present and was probably destroyed. In both cases there was a displacement of the mid-portion of the medial rectus muscle into an area of bony defect not seen on the axial and coronal views. Sagittal images demonstrated continuity between the anterior and posterior segments of the medial rectus muscle in each case. CONCLUSION: Surgical strategies are dependent on accurate interpretation of MRI scans. Muscle displacement may result in axial and coronal orbital imaging misinterpretation. Sagittal views were essential to determine muscle integrity.

Orbital wall approach with preoperative orbital imaging for identification and retrieval of lost or transected extraocular muscles.

PURPOSE: To report the results of an anterior approach along the orbital wall to recover a lost or transected extraocular muscle. METHODS: This is a retrospective review of lost or transected muscles retrieved by an anterior orbitotomy approach to the adjacent orbital wall because they were unable to be recovered by a standard conjunctival approach. Magnetic resonance imaging or computed tomography was performed on all subjects before surgery. RESULTS: Six patients underwent anterior orbitotomy via an orbital wall approach; all had undergone an attempted retrieval from a standard transconjunctival approach that failed. Five muscles had been lost from surgical or traumatic transection, and 1 muscle had been lost during strabismus surgery. The muscle location at retrieval ranged from 20 to 25 mm (mean, 23 mm) posterior to the limbus. The duration that these muscles were disinserted ranged from 7 days to 7.5 years (mean, 24 months). Preoperative deviation in primary gaze ranged from 15 to 50 PD, whereas first day postretrieval deviations all measured less than 8 PD. After a mean follow-up of 162 weeks, the mean deviation in primary gaze was 2 PD (range, orthotropia to 7 PD of esotropia). CONCLUSIONS: Anterior orbitotomy along the orbital wall with preoperative orbital imaging of extraocular muscle anatomy and function combine to create a valuable approach for retrieval of a lost or transected muscle. This technique may successfully retrieve lost or transected muscles that previously were irretrievable when using a standard transconjunctival approach.

Timing of postoperative adjustment in adjustable suture strabismus surgery.

PURPOSE: The use of adjustable sutures in strabismus surgery has increased the rate of surgical success. Little data are available on the optimum timing for postoperative adjustment after strabismus surgery. We wanted to compare 2 common practices of adjustable suture technique after strabismus surgery. METHODS: Two comparable groups of 40 patients each, who had strabismus surgery with adjustable suture technique, were prospectively studied. Group A had early adjustment the same day of the surgery about 6 hours after the operation, and group B had late adjustment the next day about 24 hours after the operation. Subjective scoring tables were used to evaluate the pain felt by the patient before, during, and after the adjustment and any difficulties of the adjustment process. Requirements of postoperative pain medications and final alignment 6 weeks after surgery were also compared. RESULTS: Despite adequate statistical power, no significant differences were found between the groups regarding pain before, during, and after adjustment, difficulties performing the adjustment, and final alignment after 6 weeks (P > .05). Both adjustment schedules were equally associated with mild to moderate pain before, during, and after the adjustment. In the first 24 hours after surgery, no overall difference in the use of pain medications was found. Nausea and vomiting in the first 24 postoperative hours were more common in the early adjustment group (P = .02). CONCLUSION: The surgeon can feel free to choose the timing for postoperative adjustment. However, when performing an early adjustment, the surgeon should be especially prepared to control nausea and vomiting.

Vertical rectus muscle augmented transposition in Duane syndrome.

INTRODUCTION: Reduction or elimination of face turn and esotropia in the primary position while maintaining the largest possible diplopia-free field are the major surgical goals in Duane syndrome with esotropia. Unsatisfactory postoperative results may occur because of limitation in adduction, poor abduction, or induced vertical deviations. Recent reports have shown enhanced results from rectus muscle transposition techniques when a lateral posterior augmentation fixation is placed. METHODS: Preoperative and postoperative data of 2 groups of subjects who had Duane syndrome with esotropia in primary position and markedly reduced abduction were comparatively analyzed. Group A consisted of subjects who had transposition of both vertical rectus muscles to the lateral rectus muscle with a posterior lateral augmentation suture placed in each transposed muscle. Group B subjects had transposition of both vertical rectus muscles to the lateral rectus muscle without the posterior lateral augmentation suture. RESULTS: A total of 32 subjects in group A and 22 subjects in group B were analyzed. In group A, anomalous head position improved 19.1 degrees +/- 10.3 degrees compared with group B subjects who improved 10.6 degrees +/- 5.8 degrees (P <.05). In group A, esotropia in primary position improved 16.4 +/- 9.2 PD compared with group B subjects who improved 8.5 +/- 6.9 PD (P <.05). CONCLUSIONS: Subjects with Duane syndrome and esotropia in primary position who had undergone augmented transposition of the vertical rectus muscles obtained improved head position and better alignment in primary position and had a reduction in the incidence of reoperation for undercorrection when compared with similar patients who had undergone vertical rectus muscle transposition without posterior lateral augmentation sutures.

Medial rectus resection(s) with adjustable suture for intermittent exotropia of the convergence insufficiency type.

BACKGROUND: The surgical results for intermittent exotropia of the convergence insufficiency type have been reported to be of varying success. The purpose of this study is to evaluate the surgical results of medial rectus muscle (MR) resection(s) with adjustable suture for this condition. METHODS: Twenty-one consecutive patients with intermittent exotropia of the convergence insufficiency type were included in this retrospective study. All patients had a history of prolonged difficulties at near work unrelieved by nonsurgical treatment. Unilateral or bilateral MR resection(s) were done with the adjustable suture, which was tied at the first postoperative day. The target angle was an esotropia of 10 to 20 PD at distance and an esotropia of 5 to 10 PD at near. Postoperatively Fresnel prisms were used temporarily in patients manifesting a consecutive esotropia with diplopia at distance. Postoperative follow-up period was between 6 months and 24 months with a mean of 9.1 months. RESULTS: MR resection(s) with the adjustable suture reduced the mean exodeviation at near from 25.7 to 3 PD. It also reduced the exodeviation at distance from 11.4 to -2 PD (esodeviation). The mean near-distance difference was collapsed from 14.3 PD preoperatively to 5 PD postoperatively. CONCLUSIONS: MR resection(s) with adjustable suture combined with intentional postoperative aggressive overcorrection and the use of Fresnel prisms is useful in intermittent exotropia of the convergence insufficiency type. The intentional overcorrection during the immediate postoperative period at distance and near is required to prevent long-term undercorrection.

Indocyanine green angiography of the anterior segment in patients undergoing strabismus surgery.

BACKGROUND: Anterior segment imaging using fluorescein angiography is only suitable in lightly pigmented irides as the brown pigmentation of the iris masks fluorescein transmission. Indocyanine green (ICG) angiography has excellent penetration of pigment epithelium and, therefore, has potential application in detecting perfusion changes of dark irides after strabismus surgery. METHODS: A prospective study was conducted on patients older than 15 years undergoing strabismus surgery. A fundus camera was focused on the arteriolar tufts of the pupillary margin and 50 mg of ICG (concentration of 12.5 mg/ml) was given intravenously. Images were then obtained at 1 minute intervals of 5 minutes' duration. RESULTS: 45 patients with a mean age of 54.6 years and a mean follow up period of 8.6 weeks were studied. There were 23 patients in the primary surgery group, 11 in the secondary surgery group, and 11 in the staged group. Iris ICG angiograms were successfully performed in all patients. No persistent filling defect was detected in the primary and secondary horizontal recti surgery groups or in the secondary or staged vertical and combined vertical rectus groups 6-8 weeks postoperatively. 57% of both primary vertical and combined vertical and horizontal groups showed defects in the early postoperative phase. Only three cases demonstrated late perfusion defects in this series. CONCLUSION: ICG can detect iris perfusion changes in dark irides after strabismus surgery. Iris reperfusion was achieved in the majority of the cases.

Use of apically based periosteal flaps as globe tethers in severe paretic strabismus.

OBJECTIVE: To evaluate the technique of using an intact autogenous periosteal flap for tethering of the globe in patients with severe paretic strabismus. METHODS: We performed a periosteal flap procedure on 5 patients and followed their postoperative course. The flap was created from the medial, lateral, or superior orbital walls. A description of the harvesting and manipulation of the flap and the initial postoperative findings are presented. RESULTS: All patients showed marked reduction in their postoperative strabismic deviation compared with preoperative measurements. Greater early postoperative swelling was noted after this procedure than with the standard strabismus surgery. No complications were experienced during or after surgery. Two patients required a second operation for adjustment of the periosteal flap for adequate alignment. CONCLUSIONS: The vascularized periosteal flap technique provides an excellent tether for the globe. Early and late stability has been favorable.

Posterior fixation sutures: a revised mechanical explanation for the fadenoperation based on rectus extraocular muscle pulleys.

PURPOSE: To determine the effect of the rectus extraocular muscle pulleys on the fadenoperation, an operation designed to fixate the posterior muscle belly to the underlying retroequatorial sclera. METHODS: First, duction into the field of action of the operated-on muscle was quantified retrospectively after fadenoperation. Magnetic resonance imaging was then performed prospectively after surgery to verify anatomic changes. Forced duction testing was performed prospectively during surgery before and after faden placement. Finally, computed tomography in a cadaver containing radiographic markers was performed prospectively to determine the effect of fadenoperation on the position of the medial rectus insertion relative to its pulley. RESULTS: Mean maximum adduction after medial rectus fadenoperation was 18 degrees (range, 10 to 25 degrees; 13 eyes). Fadenoperations combined with large medial rectus recessions restricted adduction more than fadenoperations combined with smaller recessions (P = .019), but even fadenoperations without recessions substantially restricted adduction. Mean maximum abduction after lateral rectus fadenoperation was 40 degrees (range, 25 to 45 degrees; four eyes). Axial magnetic resonance imaging in two eyes demonstrated a smaller loss of muscle tangency to the globe during contraction than predicted by geometric models. Forced ductions in nine patients performed immediately after faden placement demonstrated a new mechanical restriction to duction toward the operated-on muscle. Cadaveric computed tomographic scans demonstrated posterior displacement of the medial rectus pulley during adduction after fadenoperation. CONCLUSIONS: Posterior fixation sutures do not significantly decrease muscle torque during contraction. Because posterior fixation sutures posteriorly displace the pulley sleeve during duction toward the operated-on muscle, the mechanical restriction after surgery probably represents the force deforming the pulley. This mechanical restriction may account for the limitation in duction seen after fadenoperation.

Magnetic resonance imaging after surgical transposition defines the anteroposterior location of the rectus muscle pulleys.

INTRODUCTION: Connective tissue pulleys serve as the functional origins of the rectus extraocular muscles (EOMs) and constrain the sideslip of the posterior EOM bellies after transposition surgery. Anterior to the pulleys, EOM paths appreciably displace to reach their transposed insertions. The inflection points in the EOM paths from minimal posterior displacement to maximal anterior displacement should define the anteroposterior location of the EOM pulleys after transposition. METHODS: Contiguous cross-sectional magnetic resonance images were obtained in planes perpendicular to the long axis of the orbit over its entire anteroposterior extent before and after operation in 6 patients who underwent rectus muscle transposition surgery. Four patients underwent full tendon width transposition of the vertical rectus muscles laterally for lateral rectus palsy. Two of these patients had augmentation of the transposition with sutures that fixated the temporal margins of the transposed muscles posteriorly to the sclera adjacent to the borders of the lateral rectus muscle. One patient underwent full tendon width transposition of the horizontal rectus muscles superiorly for superior rectus palsy. One patient underwent full tendon width transposition of both lateral rectus muscles inferiorly for "A" pattern esotropia. Paths of EOMs were defined relative to the area centroid of the orbit. Pulley locations were inferred from EOM paths. The postoperative change in EOM pulley location was obtained by subtracting the preoperative pulley location from the postoperative pulley location for each image plane. RESULTS: For all patients, the postoperative change in EOM belly location was relatively small posterior to the globe-optic nerve junction. The 2 patients with abducens palsy who underwent placement of posterior augmentation sutures, however, demonstrated a significantly larger displacement of the posterior vertical rectus paths compared with similar patients who did not receive augmentation sutures. For all horizontally transposed vertical rectus muscles and inferiorly transposed lateral rectus muscles, the inflection of the EOM path began 3 mm anterior to the globe-optic nerve junction. For the superiorly transposed medial rectus muscle and lateral rectus muscle, the inflection began 6 mm anterior to the globe-optic nerve junction. CONCLUSIONS: The anteroposterior locations of the EOM pulleys can be defined by analysis of EOM displacement after transposition surgery. Augmentation of transpositions by posterior suturing displaces the EOM pulleys substantially more than nonaugmented transpositions.

Instrument-induced measurement errors during strabismus surgery.

PURPOSE: The purpose of this study was to determine the clinical setting where errors in measurements of muscle position during strabismus surgery made by the Scott curved ruler or by calipers become important and to characterize the magnitude of those errors. METHODS: Geometric analysis was used to determine the measurement error between true arc lengths of 3.0 to 20.0 mm versus Scott curved ruler measurements and caliper measurements for axial lengths ranging from 18 to 30 mm. RESULTS: For measurements less than 9.0 mm, neither the Scott curved ruler nor calipers had any clinically important measurement error for any axial length. For axial lengths substantially smaller than 21 mm or larger than 24 mm, the Scott curved ruler, although more accurate than calipers, caused clinically important measurement errors with arc length measurements as small as 12 mm in very small eyes and 14 mm in large eyes. For axial lengths of 30 mm or more, both calipers and the Scott curved ruler had similar accuracy for measuring long arc lengths. CONCLUSIONS: Both the Scott curved ruler and calipers are accurate in measuring arc lengths 9.0 mm or less. For longer arc length measurements, accuracy becomes dependent on axial length. The Scott curved ruler, although substantially more accurate than calipers for most common axial lengths, can introduce clinically important measurement errors when measuring arc lengths as small as 12 mm. Axial length should be considered when measuring muscle position during strabismus surgery.

The results of adjustable suture technique in paediatric strabismus surgery.

PURPOSE: Adjustable suture technique (AST) has been shown to be an effective treatment method in adult strabismus. The application of AST is not well studied in children due to potential poor cooperation during adjustment and the concern that the adjustment process can not be completed. The present series evaluates the efficacy and safety of this technique in a preselected group of children between 7 and 15 years of age. METHODS: A retrospective review of 89 consecutive children undergoing AST was completed to assess: (1) the ability to perform and complete adjustment in children; (2) the frequency of need to perform adjustment; and (3) accuracy of surgical alignment. Only patients with horizontal rectus muscle surgery were included. RESULTS: All children successfully completed the AST on the first post-operative day. Of the 89 patients, 24 (27%) required further adjustment by the AST. The mean follow-up period was 13.1 months. Fifty-three patients (60%) had previous strabismus surgery (range 1 to 5 operations). Sixty-six (74%) patients achieved successful alignment. Complications included slipped muscles in 1 case and difficulty in recession of the lateral rectus muscle in 1 patient. CONCLUSIONS: Twenty-seven per cent of the patients required post-operative adjustment. The AST achieved an overall 74% successful alignment. Application of the AST should be considered in children with horizontal deviations over age 7 years, especially in the reoperations of esotropia.

The effect of ocular dominance on the performance of professional baseball players.

OBJECTIVE: The purpose of the study was to determine whether a performance difference exists between baseball players with "same" (right-right) and "crossed" (right-left) hand-ocular dominance. DESIGN: A cohort study design was used. PARTICIPANTS: Four hundred and ten major and minor league members of the Los Angeles Dodgers professional baseball team. INTERVENTION: Measurement of ocular dominance. MAIN OUTCOME MEASURES: Batting average and earned run average (ERA). RESULTS: Same/crossed dominance (with P values in parentheses) are as follows: Batting averages: major league-0.271/0.251 (0.20); minor league-0.274/0.270 (0.57); ERA: major league-3.34/3.56 (0.66); minor league-4.00/4.20 (0.54). CONCLUSIONS: Hand-ocular dominance patterns do not have an effect on batting average or ERA.

Ocular torsion as a complication of scleral buckle procedures for retinal detachments.

BACKGROUND: Strabismus can occur in as many as 30% of patients after scleral buckle procedures for retinal detachments. Most previous case series have reported on horizontal and vertical deviations. This study examines the frequency of torsion after scleral buckle procedures, the abnormalities of extraocular muscles seen during strabismus surgery, and the surgical procedures effective in improving torsion. METHODS: A chart review examined the records of all patients coming to a strabismus referral practice with diplopia reported > or =6 months after scleral buckle procedures. RESULTS: Forty-six percent of patients with diplopia after scleral buckle operations had torsion (88% extorsion, 12% intorsion). The 2 mechanisms that caused extorsion most frequently were inadvertent production of a superior oblique muscle palsy and tightening of the inferior rectus muscle from the underlying scleral buckle. Other mechanisms of extorsion were also seen. The mechanism for production of intorsion was scarring of the superior oblique muscle to the nasal border of the insertion of the superior rectus muscle. Surgical procedures were successful in reducing torsion 4 degrees or more in 59% of cases. CONCLUSION: In patients undergoing surgery for torsion after a scleral buckle procedure, exploration of the superior oblique muscle and the inferior rectus muscle may yield information about the mechanism involved in the production of the torsion.

Dissociated vertical deviation and head tilts.

INTRODUCTION: The association of anomalous head posture and dissociated vertical deviation does not seem to be appreciated, as evidenced by the paucity of literature linking these two conditions. METHOD: The series describes 14 patients who had an anomalous head posture and dissociated vertical deviation. The assumed head tilts appeared to decrease the magnitude and improve the motor control of dissociated vertical deviation. RESULTS: Twelve of 14 patients tilted their heads contralateral to the eye with the dissociated vertical deviation, or away from the eye with a larger amount of dissociated vertical deviation if the disorder was bilateral. Two patients tilted their heads to the same side as the eye with the dissociated vertical deviation. Forced head tilt-testing in the opposite direction showed an increase in the magnitude of the dissociated vertical deviation or poorer control of the deviation. Dissociated vertical deviation was not related to oblique muscle dysfunction. Peripheral fusion was demonstrated in 10 patients, as evidenced by low-grade stereopsis or Worth 4 dot fusion at near. One patient did not show any demonstrable fusion with conventional tests. Another did not show evidence of stereopsis, but Worth 4 dot testing was not performed. Two other patients were too young to cooperate with sensory testing. Anomalous head posture was controlled or minimized after the control of the dissociated vertical deviation by surgery in four patients. Two patients showed improved stereopsis after surgery for dissociated vertical deviation. CONCLUSION: Dissociated vertical deviation should be included in the differential diagnosis of an ocular cause of head tilts. Forced contralateral head tilttesting will confirm whether dissociated vertical deviation is the cause if motor control of the dissociated vertical deviation worsens or becomes manifest rather than latent. The presence of an anomalous head posture in patients with dissociated vertical deviation can be improved with strabismus surgery.