Adjustable Bilateral Superior Oblique Tendon Advancement for Bilateral Fourth Nerve Palsy

Novel superior oblique anterior fiber plication with or without adjustable sliding knot for extorsion

PURPOSE

To report a novel surgical technique to correct excyclotropia, consisting of a superior oblique anterior fibers plication (SOAFP) with or without a hemihangback anterior knot, allowing access for postoperative adjustment.

METHODS

A retrospective interventional case series was conducted. Fourteen patients, 21-92 years of age, underwent SOAFP (18 eyes, 14 eyes on adjustable), at the Mayo Clinic in Rochester, Minnesota. SOAFP was the only procedure performed in 12 eyes; in 6 it was performed in conjunction with up to four horizontal rectus muscle recession, resection, and/or plication. Ocular alignment was assessed with prism and alternate cover and double Maddox rod tests; preoperatively, at initial and final (closest to 6-8 weeks) postoperative visits.

RESULTS

Preoperative torsion ranged from 2° to 30° of extorsion (mean, 10.14 ± 7.01). A SOAFP of 2-30 mm (mean, 8.93 ± 5.63) was performed. At the initial postoperative examination, mean intorsional shift was 11.18 ± 7.37, accounting for 1.86° ± 1.04° of correction per millimeter of plication. Three eyes were adjusted after the initial visit to obtain a stronger plication effect targeting of 5° intorsion. At the final visit, 61 ± 23 days postoperatively, mean extorsion was 1.21° ± 2.29°, ranging from 5° of extorsion to 3 of intorsion. Mean final intorsional shift was 9.14 ± 7.53°, accounting for a 1.16 ± 0.50° of correction per millimeter of plication. Of our 14 patients, 13 had improvement in diplopia.

CONCLUSIONS

In our study cohort, SOAFP allowed for targeted and easily adjustable correction of extorsion.

Disinsertion-distal myectomy and tucking of inferior oblique combined with superior oblique full tendon advancement in superior oblique palsy

PURPOSE

To assess the preliminary outcomes of inferior oblique (IO) disinsertion-distal myectomy and tucking combined with superior oblique (SO) full tendon advancement in patients with Knapp II or III superior oblique palsy.

METHODS

This single-centered retrospective study included 16 eyes from 13 patients with Knapp Class II or III SO palsy. All patients underwent IO disinsertion-distal myectomy and tucking combined with SO full tendon advancement while under general anesthesia. Pre- and post-operative levels of vertical deviation in the primary position, abnormal head position, IO hyperfunction and SO hypofunction, torsion, as well as the presence of diplopia, were all measured, and the differences were statistically compared.

RESULTS

Pre-operatively, 12 patients had abnormal head positions, and two had diplopia. The pre-and post-operative levels of IO hyperfunction and SO hypofunction, as well as a vertical deviation in the primary position and torsion, all differed statistically significantly (p < 0.01).

CONCLUSIONS

Inferior oblique disinsertion distal myectomy and tucking combined with SO full tendon advancement surgery appears to be an effective procedure in patients with congenital and acquired Knapp Class II or III SO palsy.

A simple marking system for accurate intraoperative monitoring and adjustment of cyclotorsion strabismus surgery

Ocular cyclotorsion is treatable only with surgery. The surgical procedure must be tailored individually to the specific etiologies causing the horizontal and vertical strabismus and its torsional components. An adjustable surgical approach is often used for postoperative or intraoperative adjustments. However, the methods currently used have some limitations. In this study, we propose a simple intraoperative marking system for all cyclotorsion correction surgery. The proposed marking system used three sets of surface markers: external horizontal markings, ocular horizontal markings, and surgical torsion markings, drawn in sequence. We retrospectively analyzed the surgical results using this novel marking system in this single-center, single-surgeon study. Fifteen patients with cyclotorsion who underwent treatment using the proposed marking system as an intraoperative aid between August 2019 and August 2021 were included. The medical charts were thoroughly reviewed, and the pre-and postoperative subjective and objective cyclotorsion were analyzed. Among the study subjects (10 males, 5 females; age range: 6-89 years), 13 had excyclotorsion and 2 incyclotorsion. Preoperative mean net subjective cyclotorsion measured by the double Maddox rod (DMR) test was 6.0° (standard deviation: 10.8°) and mean net disc-to-fovea angle (DFA) was 20.23° (13.21°). The postoperative net DMR and DFA were 0.2° (2.1°) and 14.09° (5.97°), respectively. The mean absolute net DMR and DFA being treated were 9.8° (4.8°) and 9.76° (4.61°). Overall, the proposed intraoperative marking system is a simple and quantitative method to assess, monitor, and adjust the torsional aspect for all strabismus surgeries.

Modified Harada-Ito Procedure with Intraoperative Adjustable Sutures Using a Mendez Ring for Excyclotorsion

Purpose: We report a case of using a modified Harada-Ito procedure with intraoperative adjustment via a Mendez ring in a patient with bilateral superior oblique palsy, resulting in satisfactory postoperative outcomes.Case summary: A 47-year-old male patient presented with bilateral diplopia after cerebral hemorrhage. Bilateral superior oblique palsy was diagnosed, and double Maddox rod tests confirmed 20° of excyclotorsion in both eyes. After 6 months of observation, surgical correction was attempted. To check the amount of cyclodeviation, a modified Harada–Ito procedure was performed on the superior oblique muscle after marking at the 6 and 12 o'clock positions of the corneal limbus. Following the procedure, a Mendez ring was placed on the limbus to check for the amount of incyclotorsion. Thirty degrees of incyclotorsion was aimed at both eyes, and a 5-mm resection of the right superior oblique tendon was performed for additional correction. There was no complaint of diplopia at 6 months postoperatively, and no deviation was observed.Conclusions: A modified Harada-Ito procedure with intraoperative adjustment using a Mendez ring effectively corrected excyclotorsion with torsional diplopia.

Surgical outcome of graded Harada-Ito procedure in the treatment of torsional diplopia ‒ a retrospective case study with long-term results

To review and evaluate the surgical outcomes of the Fells-modified Harada-Ito procedure using a dosage scale approach with long-term follow up in patients with torsional diplopia. The records of patients who underwent the modified Harada-Ito procedure by the same surgeon during 2012-2019 were retrospectively reviewed regarding pre- and post-operative data and individual dose-scale used for the surgery. The modified Harada-Ito procedure involved advancing the anterior half of the superior oblique tendon toward the inferior edge of the lateral rectus muscle by a distance determined using a five-graded scale. A total of 27 patients (mean age 57.6 years, range, 22-81 years; 10 female) were included. Evaluating surgical outcome showed a significant difference in pre- to post-operative cyclodeviation (p = <0.001). Pre-operative mean extorsion was -10.4° and mean torsional correction achieved was 7.7°. The dose-effect relationship showed a wide spread effect, yet yielded a high success rate. All but two patients were symptom free from their torsional diplopia at the last post-operative evaluation, on average 24 months after surgery. Post-operative results and the dose-effect of the modified Harada-Ito corresponded with the aimed-for correction of torsional diplopia.. Fusion evaluation and individually based pre-operative assessments proved essential in determining individual doses for successful surgical outcomes.

Torsional incomitance after asymmetrically adjusted Harada-Ito procedures for the simultaneous correction of vertical and torsional deviations in bilateral trochlear nerve palsy

BACKGROUND

Adjustable bilateral Harada-Ito procedures have been described, sometimes with asymmetric adjustment used to correct vertical misalignment when coexisting with torsional strabismus. We investigated the causes of significant postoperative torsional incomitance noted in some patients undergoing these procedures.

METHODS

The medical records of patients who underwent bilateral Harada-Ito procedures for bilateral trochlear nerve palsy between 1980 and 2018 were reviewed retrospectively. Cases with simultaneous operation on any other oblique or vertical rectus muscle were excluded. Surgical results, especially using Lancaster red-green (Lan R-G) plots, were correlated with the procedures performed.

RESULTS

A total of 17 patients were included. At their last follow-up visit (mean, 12 months after surgery), 9 were diplopia free. Of the 8 with continuing diplopia, 2 had undercorrection and 1 had Brown syndrome. In 5 patients with continuing diplopia, there was relative intorsion of the eye movement paths in upgaze and relative extorsion of these paths in downgaze, a type of torsional incomitance. Asymmetric adjustment with tightening of one superior oblique tendon, and often loosening of the contralateral superior oblique tendon, had been performed in those 5 cases. Only 1 of the successful cases had the same type of asymmetric adjustment. There was a positive association between the severity of the preoperative Lan R-G pattern and postoperative diplopia.

CONCLUSIONS

Asymmetric adjustment of bilateral Harada-Ito procedures when attempting to correct the coexisting vertical misalignment can cause significant torsional incomitance with incomplete correction of extorsion in downgaze and intorsion in upgaze. This pattern may result in postoperative diplopia that is surgically challenging to correct.

[History of Superior Oblique Muscle Surgery]

The superior oblique muscle has the longest tendon among the six extraocular muscles and serves complex functions. Surgery on the superior oblique muscle is considered the most complicated and difficult procedure in the field of strabismus. This article focuses on the history of superior oblique muscle surgeries, including superior oblique weakening procedure and superior oblique strengthening procedure. We discussed the advantages, disadvantages, and indications of each type of surgery, providing colleagues in the field of ophthalmology with a comprehensive understanding of superior oblique muscle surgery and facilitating the carefully weighed decision to choose and perform the procedure.

Disorders of the Fourth Cranial Nerve

ABSTRACT

This review of disorders of the fourth cranial nerve includes discussion on anatomy, examination techniques, congenital and acquired etiologies, differential diagnosis, and management options. The findings of the superior oblique muscle on orbital MRI in patients with fourth nerve palsy have had a major impact on our understanding of this cranial neuropathy. In addition, briefly reviewed are rare disorders of the fourth nerve: superior oblique myokymia, Brown syndrome, and ocular neuromyotonia. It behooves the clinician to have a clear understanding of the role that the fourth cranial nerve plays in a variety of neuro-ophthalmic conditions.

Superior oblique tendon advancement: its success as single or combined muscle treatment for selected cases of unilateral superior oblique palsy

Purpose: To evaluate the efficacy of single or combined superior oblique tendon (SO) advancement for selected cases of unilateral superior oblique palsy (SOP).Methods: The medical records of 14 patients who underwent single or combined superior oblique tendon advancement in one institution from May 2017 to October 2018 were reviewed. All subjects with a diagnosis of unilateral SOP who underwent single or combined SO tendon advancement surgery were included. The goal of the surgery was to correct the hypertropia and head tilt. The single or combined SO tendon advancement surgery was selected based on the amount of hypertropia or head tilt and the Knapp classification of the SOP. The information recorded included pre- and postoperative deviation angle and ocular motility findings. The degree of upshoot in adduction was graded pre- and postoperatively.Results: Fourteen patients between the age of 3 and 52 years with unilateral superior oblique palsy were selected to undergo SO tendon advancement. Single SO tendon advancement was carried out in eight acquired Knapp class II or residual SOP patients. SO tendon advancement combined with contralateral inferior rectus recession was carried out in two acquired Knapp class II patients. SO tendon advancement combined with ipsilateral inferior oblique myectomy was carried out in four congenital Knapp class III patients. The changes in pre- and postoperative hypertropia at primary gaze in single SO tendon advancement patients were from 6.25 ± 2.12 prism diopters to 0.86 ± 1.46 prism diopters. The changes in degree of upshoot in adduction were from +1.86 to +0.21. Conclusions: SO tendon advancement worked well as single or combined muscle procedure to treat unilateral superior oblique palsy.