A Case of Trochlear Nerve Schwannoma Presenting with Binocular Diplopia

PURPOSE: To report a case of unilateral trochlear nerve schwannoma in a patient without neurofibromatosis. CASE SUMMARY: A 58-year-old male presented with acute onset of diplopia which developed 10 days prior. Alternate prism cover test, ductions and versions and Bielschowsky three-step test were compatible with left superior oblique muscle palsy. High-resolution magnetic resonance imaging showed a 6-mm-sized lobulated mass in the cisternal segment of the left trochlear nerve passing lateral to the brainstem. An additional thin-section gadolinium-enhanced orbit magnetic resonance imaging showed definite enhancement in the entire portion of the lobulated mass, compatible with a trochlear nerve schwannoma. Diplopia was managed conservatively with prism glasses and regular follow-up examinations were recommended without further treatment. CONCLUSIONS: A trochlear nerve tumor should be considered in adults who develop diplopia associated with acquired superior oblique muscle palsy.

Comparison of Double Maddox Rod Test and Bagolini Striated Lens Test for Superior Oblique Palsy

PURPOSE: We compared the results of the double Maddox rod test (DMRT), which is commonly performed in clinics as a subjective torsion test for superior oblique muscle palsy, with those of the Bagolini striated lenses test (BSLT) in a least dissociating condition to predict the cyclofusional capacity. METHODS: Twenty-five patients with acquired superior oblique muscle palsy were tested for degree of subjective torsion with DMRT and BSLT in primary position and down-gaze in Daegu Catholic University Hospital from May 2014 to March 2015. DMRT was performed in a dark room and BSLT in a lighted room. RESULTS: Mean extorsional degree in primary position was 3.40 ± 2.58° on DMRT and 1.88 ± 2.92° on BSLT, a significant difference (p = 0.000). In down-gaze, mean extorsional degree was 4.16 ± 2.90° with DMRT and 2.40 ± 2.90° with BSLT (p < 0.001). CONCLUSIONS: The subjective torsional measurement with BSLT was significantly smaller than with DMRT, and the cyclofusional capacity in patients with acquired superior oblique palsy was 1.5° in primary position and 1.8° in down-gaze. BSLT is helpful in addition to DMRT and fundus photograph for the evaluation of cyclotropia in patients with superior oblique muscle palsy, and this test may yield clinically important information for predicting the cyclofusional capacity of patients with superior oblique muscle palsy.

The Effect of Inferior Oblique Muscle Transposition in Primary and Secondary Inferior Oblique Muscle Overaction

PURPOSE: To evaluate and compare the effect of transposition of inferior oblique muscle in patients with primary inferior oblique muscle overaction and secondary due to superior oblique muscle palsy. METHODS: The present study included 41 patients (53 eyes), who appeared to have primary or secondary inferior oblique muscle overaction due to superior oblique muscle palsy and received transposition of inferior oblique muscle with at least 3 months of follow-up. Patients were retrospectively analyzed to compare the effect of correction and its prognosis. Inferior oblique muscle overaction was graded as +1 to +4 according to the severity. Successful surgery was defined as postoperative inferior oblique muscle overaction from 0 to +1 and failure as above +2. Hypertropia in primary gaze was also recorded to evaluate the effect of correction. RESULTS: Twenty-six (35 eyes) and 15 (18 eyes) patients with primary and secondary inferior oblique muscle overaction due to superior oblique muscle palsy, respectively, received transposition of inferior oblique muscle. Patients with primary inferior oblique muscle overaction showed correction of 2.1 +/- 0.9 with preoperative inferior oblique muscle overaction of 2.0 +/- 0.7. Patients with secondary inferior oblique muscle overaction showed a correction of 2.3 +/- 0.9 with preoperative value of 2.3 +/- 0.8. Each 3.2 +/- 4.1 prism diopters (PD) and 6.5 +/- 5.3 PD of hypertropia at primary gaze showed correction of 3.0 +/- 7.4 PD and 6.3 +/- 5.1 PD, respectively, in each group. CONCLUSIONS: Primary and secondary inferior oblique muscle overaction due to superior oblique muscle palsy showed no difference in correction of overaction and hypertropia after transposition of inferior oblique muscle. Except for presence of inferior oblique muscle underaction, the correction appears effective with good prognosis.

The Effect of Inferior Oblique Muscle Surgery in Congenital Superior Oblique Palsy

PURPOSE: To compare the postoperative results of inferior oblique muscle operation in congenital superior oblique palsy (CSOP) according to the preoperative vertical deviation. METHODS: This study reviewed medical records of 26 patients who were diagnosed as CSOP with the largest vertical deviation at adducted position and incomitant vertical strabismus from May 2003 to April 2004 at hospital. The patients were divided into two groups, the group 1 (18 patients) shows less than 20 prism diopter (PD) vertical deviation at the primary position, the group 2 (10 patients) shows no less than 20 PD vertical deviation at the primary position preoperatively. We performed operation of the inferior oblique muscle (IOM) for both group. We evaluated the surgical effect at the primary position and both lateral gaze after 3 months. and performed reoperation as needed. RESULTS: Mean correction amount of vertical deviation at primary position of two groups were 11.6+/-2.7 PD in the group 1 and 7.4+/-3.5 PD in the group 2. Postoperative vertical deviation was decreased compared to preoperative value and it was statistically significant. But there were statistically significant differences in the corrected amount after inferior oblique muscle operation between two groups at all gazes. Surgical result of group 1 was successful (100%), but in group 2, all failed (100%) and needed reoperation. CONCLUSIONS: This study showed that corrected amount with IOM operation was smaller in CSOP with no less than 20 PD vertical deviation at primary position and incomitant vertical strabismus. It may be taken into consideration when operation for rectus and oblique musle were performed simultaneously in CSOP.

A Case of Congenital Absence of the Superior Oblique Muscle

PURPOSE: To report a patient with adsence of the superior oblique (SO) muscle of the right eye, who showed improvement after surgery for hyperdeviation and exotropia. METHODS: A four-year-old girl who presented with 14 PD exotropia, and 25 PD hypertropia of the right eye had a history of myectomy of the right inferior oblique (IO) muscle for bilateral SO palsy as a two-year-old. At the time of surgery, severely fibrotic pseudotendon of IO and Tenon's capsule attached to the insertional area of the inferior rectus muscle was found. IO was remyectomized with adhesiolysis. Lateral rectus and superior rectus (SR) muscles were recessed 6.5mm and 7mm, respectively. After exposure of SR, the absence of SO was found. MRI taken at postoperative one day showed definite SO absence. RESULTS: Three weeks after surgery, 4 PD of left hyperphoria at distant and 5 PD of left hyperphoria at near were observed. Right hyperdeviation was not detected. At postoperative 7 months, 4 PD of exophoria, 6 PD of right dissociated vertical deviation (DVD) and 10 PD of left DVD were seen at distant. A small left hyperdeviation was intermittently noted at upgaze and was cautiously followed. CONCLUSIONS: Absence of the superior oblique muscle is rare. However, such absence should be suspected when apparent superior oblique palsy accompanies with severe hyperdeviation and horizontal deviation. MRI or CT is helpful in the diagnosis of this condition and direct confirmation is needed.

The Effect of Modified Anterior Transposition of the Inferior Oblique Muscle for Hypertropia in Superior Oblique Muscle Palsy with Inferior Oblique Muscle Overaction

PURPOSE: The authers studied the effect of modified anterior transposition of the inferior oblique muscle for hypertropia in superior oblique muscle palsy combined inferior oblique muscle overaction. METHODS: We retrospectively analysed 19 cases of superor oblique palsy, which were treated by modified inferior oblique muscle anterior transposition from January 1999 to march 2001. Mean follow-up was 14.6 months. The medial portion of inferior oblique muscle was transpositioned to 1mm posterior position of the temporal insertion of inferior rectus muscle and lateral portion of inferior oblique muscle was moved 5mm on imaginary line, which is the line of between temporal insertion of inferior rectus and inferior insertion of lareral rectus muscle, to the direction of inferior insertion of lateral rectus muscle from temporal insertion of inferior rectus muscle, then backward 6mm from that point perpendicularly. RESULTS: The success rates in modified anterior transposition were 94% in under 20delta of hypertropia and 89.5% in over +3 of IOOA. CONCLUSIONS: Modified anterior transposition is an effective procedure of +3 to +4 inferior oblique muscle overaction and hypertropia in superior oblique muscle palsy as a primary surgery.

Clinical Evaluation of Superior Oblique Muscle PalsyAssociated with Horizontal Deviation

PURPOSE: The purpose of this study is to provide useful clinical information for proper diagnosis of the superior oblique muscle palsy (SOP) associated with horizontal deviation. METHODS: The records of 186 patients with SOP treated surgically were reviewed. The patients who underwent surgery for horizontal deviation more than 10 PD were classified into SOP associated with horizontal deviation. RESULTS: Of 186 patients with SOP, 96 (51.6%) patients also showed horizontal deviation. In 59 patients (61.5%) of these 96 patients, chief complaint was horizontal deviation only and 24 patients (25.0%) knew their hyperdeviation. Compensatory head-tilt was shown in 52 patients (54.2%), however only 11 (11.5%) patients complained their head-tilt posture. Of 96 patients, 72 (82.3%) had horizontal deviation in the eye contralateral to the paretic eye and amblyopia occurred in the horizontally deviated eye. The frequency of exodeviation was 82.3 % and was more than that of esodeviation. The mean amount of hyperdeviation was 12.6 +/- 6.77 PD, and that of horizontal deviation was 22.9 +/- 8.13 PD in exodeviation and 22.5 +/- 9.17 PD in esodeviation, respectively ninety three patients (96.9%) showed positive Bielschowsky head-tilt test. All 83 patients who had fundus examination showed foveal extorsion. CONCLUSIONS: This study reveals that Bielschowsky head-tilt test and fundus examination for foveal extorsion are needed to diagnose SOP which is masked by prominent horizontal deviation.