Long-term outcome of full tendon vertical rectus transposition with Foster suture in unilateral complete sixth cranial nerve palsy

Outcomes and Factors Associated with Successful Strabismus Surgery for Abducens Nerve Palsies: A Retrospective Study and Literature Review

Purpose

Several studies reported surgical outcomes for abducens nerve palsy, but information on factors that affect treatment success remains lacking. These factors are crucial for developing a treatment plan and providing disease counseling. This study aimed to investigate the outcomes of strabismus surgery for abducens nerve palsy and determine the factors that influence its success, including a review of relevant literature.

Methods

This retrospective analysis included abducens nerve palsy cases, focusing on surgical interventions and relevant patient data, at the outpatient clinics of Phramongkutklao Hospital from April 1, 2012, to April 30, 2022. A relevant literature review included the surgical success rate and factors that influence surgical outcomes.

Results

This study enrolled 32 patients, including 19 with partial and 13 with complete abducens nerve palsy. The overall success rate of strabismus surgery was 78.1%. Trauma was the leading cause of abducens nerve palsy in this population (28.13%). Fisher's exact and Mann-Whitney U-tests revealed that shorter abducens nerve palsy onset and smaller preoperative angle were significantly associated with successful surgical outcomes of strabismus surgery among the groups. In contrast, subgroup analysis revealed that only preoperative smaller angles were significantly associated with good surgical outcomes in horizontal strabismus surgery. However, the vertical rectus muscle transposition group demonstrated no significant factors. The literature review revealed that the success rate of surgery in abducens nerve palsy was 25%-82.6% for horizontal rectus muscle surgery and 46.2%-91% for rectus muscle transposition.

Conclusion

The surgical success rate for abducens nerve palsy reached 78.1%, including 78.95% for partial and 76.92% for complete abducens nerve palsy. Notably, a shorter onset preceding surgery and a smaller preoperative angle significantly correlated with successful surgical outcomes one year postoperatively.

Outcomes of half-width vertical rectus transposition augmented with posterior fixation sutures for sixth cranial nerve palsy

AIM

To describe the experience with half-width vertical muscles transposition (VRT) augmented with posterior fixation sutures.

METHODS

The clinical charts of all patients, who underwent half-width VRT augmented with posterior fixation sutures for sixth cranial nerve palsy from January 2003 to December 2018, were retrospectively reviewed. For each patient, pre- and post-operatively, the largest measured angle was used for the calculations, usually resulting with the angle for distance, except in young infants, where measurements were made at near fixation using the Krimsky test.

RESULTS

Fifteen patients met the inclusion criteria for the study, of them 9 (60.0%) had also medial rectus muscle recession at the time of surgery. Mean follow-up period was 21.4±23.2mo (range 1.5-82mo). Preoperative mean esotropia was 51.3±19.7 prism diopter (PD; range 20-90 PD). Postoperative mean deviation on final follow-up was 7.7±20.2 PD (range -40 to 35 PD; P=0.018). In all patients with preoperative abnormal head position, improvement was noted. Ten (66.7%) patients had improvement in abduction and 10 (66.7%) patients reported improvement in their diplopia, by final follow-up. The addition of medial rectus recession was correlated with a larger change in postoperative horizontal deviation compared to baseline (P=0.026). Two (13.3%) patients developed a vertical deviation in the immediate postoperative period which had resolved in one of them.

CONCLUSION

Half-width VRT augmented with posterior fixation suture, with or without medial rectus muscle recession, is an effective and safe procedure for esotropia associated with sixth cranial nerve palsy. A major improvement in the angle of deviation is expected. Most patients will have improvement in their abnormal head position and diplopia.

A Review of Transposition Techniques for Treatment of Complete Abducens Nerve Palsy

Purpose:

To review various types of extraocular muscle transposition procedures for management of strabismus in sixth cranial nerve palsy with little lateral rectus (LR) muscle function, along with their pros and cons.

Methods:

We performed a comprehensive review of transposition procedures in sixth cranial nerve palsy, based on literature published anytime up to March 2021. A thorough search through PubMed and Cochrane databases was performed. All types of clinical studies on different transposition procedures in LR palsy, were included.

Results:

Eighty-six original articles in English, with full text or abstracts available, were included in the review, among which 16 are prospective studies, 48 retrospective, 3 review articles, 1 randomized clinical trial, 17 case reports, and 1 letter. Vertical rectus transposition has demonstrated promising results, especially in abduction improvement and expansion of binocular diplopia-free visual field, albeit the possible adverse effects such as anterior segment ischemia, especially in the presence of medial rectus contracture, and induced vertical deviation may become troublesome. Partial muscle transposition, single muscle transposition, and also transposition without tenotomy have all been introduced to reduce the risk of multiple muscle manipulation and ischemia. On the other hand, different adjustable transpositions are being utilized to manage concomitant or induced vertical deviations.

Conclusion:

Transposition procedures are highly effective in the treatment of esotropia caused by complete LR palsy. Various techniques for vertical muscle transposition have been proposed, with each of them having certain advantages and disadvantages.

Double-under muscle transposition: an effective surgical option for large-angle paralytic strabismus

PURPOSE

To describe our surgical outcomes using a novel muscle transposition procedure, or double-under muscle transposition (DUT), in the treatment of paralytic strabismus.

METHODS

In this surgery, the split halves of the superior and inferior rectus muscles opposite the paralyzed muscle are disinserted, crossed under both the remaining half and the paralyzed muscle, and anchored at opposite corners of the insertion of the paralyzed muscle. The medical records of consecutive patients who underwent DUT were retrospectively reviewed. Outcome measures were angle of deviation and duction deficit.

RESULTS

Seven patients were included. Diagnoses included WEBINO (n = 1), rupture of the medial rectus muscle (n = 1), and abducens nerve palsy (n = 5). DUT alone was performed in 3 patients; DUT combined with antagonist muscle recession, in 4 patients. One patient underwent the surgery bilaterally. Mean follow-up was 17 ± 18+ months (range, 7-57). Preoperative angles of distance deviation ranged from 25^Δ to 142^Δ in magnitude. All except a single patient had duction limitation of grade -5. The mean change in distance deviation for DUT alone for each operated eye was 60^Δ ± 6^Δ (53^Δ-65^Δ); for combined surgery, 69^Δ ± 23^Δ (range, 52^Δ-103^Δ). Final mean angle of deviation at distance was +2^Δ ± 3^Δ (-4^Δ to 0^Δ), although an additional surgery was required for large overcorrections in 2 patients. Duction limitation improved in all patients. One patient experienced a postoperative vertical deviation.

CONCLUSIONS

DUT may be an alternative for patients with severely paralytic strabismus not likely to resolve with previously reported muscle transposition surgeries. Overcorrection may occur in some cases.