Evaluating a new surgical dosage calculation method for esotropia

Efficacy of augmented-dosed surgery versus botulinum toxin A injection for acute acquired concomitant esotropia: a 2-year follow-up

BACKGROUND/AIMS

This study aims to evaluate the clinical efficacy of botulinum toxin type A (BTXA) injection and augmented-dosed surgery in the treatment of acute acquired concomitant esotropia (AACE), and explore potential risk factors associated with recurrence.

METHODS

A total of 104 patients diagnosed with AACE between October 2020 and January 2021 were included and voluntarily chose to undergo augmented surgery or BTXA injection. The follow-up assessments ended in November 2022. Multivariable linear regression analysis was used to identify potential factors that influence the dose-response of bilateral medial rectus recession (MRrec). Kaplan-Meier survival analyses and Cox proportional hazards models were performed to evaluate rate and risk factors for AACE relapse.

RESULTS

A total of 31 AACE patients chose augmented-dosed esotropia surgery, and 73 chose BTXA treatment. During the 2-year follow-up, the surgical group achieved more stable postoperative results with no recurrence of diplopia, while only 68.68% (95% CI 55.31% to 78.79%) patients achieved orthophoria in the BTXA group. For patients undergoing BTXA treatment, hours of near work per day were demonstrated to be a significant risk factor for AACE relapse (HR 1.29, 95% CI 1.00 to 1.67). The dose-response of augmented-dosed bilateral MRrec was positively correlated with preoperative deviation angle (R2=0.833; β=0.043, 95% CI 0.031 to 0.055; p<0.001).

CONCLUSION

Our findings provided quantitative evidence that augmented-dosed surgery would achieve more stable and favourable surgical outcomes for AACE patients compared with BTXA injection. However, BTXA treatment is still proposed for patients with small deviation angles due to its advantages of reduced trauma, operational simplicity, low cost and quick recovery.

Augmented-Dose Unilateral Recession-Resection Procedure in Acute Acquired Comitant Esotropia

PURPOSE

To compare the surgical amount of unilateral medial rectus recession and lateral rectus resection (RR) in patients with acute acquired comitant esotropia (AACE) versus common forms of esotropia and to provide dose-response reference for surgical planning in AACE.

DESIGN

Retrospective study.

PARTICIPANTS

Consecutive patients who underwent unilateral RR for AACE or common forms of esotropia correction from January 2018 to January 2022. Only patients who achieved motor and sensory success with a minimum follow-up of 3 months were analyzed.

METHODS

Group differences in the amount of medial rectus (MR) recession and lateral rectus (LR) resection were analyzed using multivariate regression models. Surgical dose responses in AACE were analyzed using multivariable regression models. Regression models were performed with and without adjustment for clinical confounders. Piecewise analysis was used to detect segmented results.

MAIN OUTCOME MEASURES

Group difference in surgical amount and dose responses of unilateral RR in AACE.

RESULTS

Fifty-four patients with AACE and 98 patients with common forms of esotropia were included. To correct comparable deviations, surgical amount performed was significant larger in AACE patients, with the adjusted group differences of 0.49 mm (95% confidence interval [CI], 0.34-0.65 mm; P < 0.001) in MR recession and 1.68 mm (95% CI, 1.25-2.11 mm; P < 0.001) in LR resection in patients with deviation < 40 prism diopters (Δ) and with a group difference of 1.22 mm (95% CI, 0.76-1.68 mm; P < 0.001) in LR resection in those with deviation ≥ 40 Δ. In AACE patients, in the adjusted model taking into account the intercept, dose responses of MR recession and LR resection in patients with deviation < 30 Δ were 5.11 Δ/mm (95% CI, 0.98-9.23 Δ/mm; P = 0.02) and 2.51 Δ/mm (95% CI, 0.57-4.45 Δ/mm; P = 0.02), respectively, and for those with deviation ≥ 30 Δ, the dose response of additional LR resection was 5.48 Δ/mm (95% CI, 4.56-6.40 Δ/mm; P < 0.001) to correct remaining deviation beyond 30 Δ.

CONCLUSIONS

These findings provide quantitative evidence that augmented-dose unilateral RR should be performed in AACE for favorable surgical outcomes. The new surgical dose calculation proposed provides reference for surgical planning.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Surgical Outcomes of Medial Rectus Recession and Lateral Rectus Resection for Large-angle Deviations of Acute Acquired Concomitant Esotropia

Purpose

This study aimed to evaluate the surgical outcomes of unilateral medial rectus recession and lateral rectus resection (R&R) for patients with large-angle deviations of acute acquired concomitant esotropia (AACE) without a neurological disease. Further, we have also suggested the surgical dosage of R&R for large-angle deviations of AACE.

Methods

This was a retrospective study of patients with AACE who underwent surgery and followed up after surgery for at least 6 months between September 2016 and March 2020. Among them, patients with ocular deviations of ≥30 prism diopters (PD) who underwent unilateral R&R were included.

Results

Seventeen patients with AACE were enrolled in this study (mean age, 23.5 years; four females). The mean amount of deviation was 40.00 PD at distance and near (range, 30–55 PD). Fifteen patients (88.2%) had myopia. The mean interval between the initial visit and surgery was 7.7 months (range, 4–20 months). All included patients had resolved diplopia after the surgery. Most patients with decreased stereoacuity displayed stereoacuity recovery after surgical treatment. At the final visit (mean follow-up period, 12.8 months), the mean angle of esodeviation was 0.82 PD (range, 6–0 PD) at distance and 0.47 PD (range, 4–0 PD) near. No patient displayed over-correction or adduction limitations in the operated eye.

Conclusions

The unilateral R&R procedure presented favorable surgical outcomes for patients with large-angle deviations of AACE. These results and proposed surgical dosage guidelines may be useful for surgeons in planning the surgical treatment of large-angle deviations of AACE.

Lateral rectus advancement versus medial rectus recession for consecutive esotropia

PURPOSE

To compare lateral rectus advancement with medial rectus recession for patients with consecutive esotropia without abduction limitation.

METHODS

Forty-three patients who developed consecutive esotropia following bilateral lateral rectus recession for intermittent exotropia were reviewed retrospectively. Twenty-two patients underwent lateral rectus advancement (lateral rectus advancement group) and medial rectus recession was performed in 21 patients (medial rectus recession group). Success rate of the surgery was based on the percentage of postoperative esophoria or exophoria of less than 8 PD, which did not require a third surgery. Mean follow-up after second surgery was 23.5 ± 8.7 months.

RESULTS

Mean consecutive esotropia in the lateral rectus advancement group was 24.8 ± 9.0 PD. Eight patients were orthophoric after second surgery; mean postoperative esophoria and exophoria/tropia was 5.4 ± 3.4 PD and 6.5 ± 5 PD, respectively. Postoperative success rate in this group was 90.9%. Mean consecutive esotropia in the medial rectus recession group was 21 ± 98.4 PD. Three patients were orthophoric after second surgery; mean postoperative esotropia/phoria and exophoria was 9.5 ± 5.0 PD and 5.2 ± 1.3 PD, respectively. Postoperative success rate in this group was 71.4%. Postoperative undercorrection rate of 4.5% in lateral rectus advancement group was significantly less than the similar measure of 28.6% in medial rectus recession group (chi-square, P = 0.03).

CONCLUSION

Advancement of the previously recessed lateral rectus has improved consecutive esotropia better than medial rectus recession.

Modified adjustable suture hang-back recession: Description of technique and comparison with conventional adjustable hang-back recession

PURPOSE

This study aims to describe and compare modified hang-back recession with the conventional hang-back recession in large angle comitant exotropia (XT).

METHODS

A prospective, interventional, double-blinded, randomized study on adult patients (>18 years) undergoing single eye recession-resection for large angle (>30 prism diopters) constant comitant XT was conducted between January 2011 and December 2015. Patients in Group A underwent modified hang-back lateral rectus recession with adjustable knot while in Group B underwent conventional hang-back recession with an adjustable knot. Outcome parameters studied were readjustment rate, change in deviation at 6 weeks, complications and need for resurgery at 6 months.

RESULTS

The groups were comparable in terms of age and preoperative deviation. The patients with the modified hang back (Group A) fared significantly better (P < 0.05) than those with conventional hang back (Group B) in terms of lesser need for adjustment, greater correction in deviation at 6 weeks and lesser need for resurgery at 6 months.

CONCLUSION

This modification offers several advantages, significantly reduces resurgery requirement and has no added complications.

Surgical Results of Symmetric and Asymmetric Surgeries and Dose-Response in Patients with Infantile Esotropia

Objectives:

To evaluate the results of symmetric and asymmetric surgery and responses to surgical amounts in patients with infantile esotropia.

Materials and Methods:

The records of patients with infantile esotropia who underwent bilateral medial rectus recession (symmetric surgery) and unilateral medial rectus recession with lateral rectus resection (asymmetric surgery) were analyzed. The results of the cases with symmetric (group 1) and asymmetric (group 2), successful (group 3) and failed (group 4) surgeries were compared, and responses to the amount of surgery were investigated.

Results:

There were no significant differences between group 1 (n=71) and group 2 (n=13) cases in terms of gender, refraction, preoperative distance deviation, anisometropia and postoperative deviation angles, binocular vision, surgical success or follow-up period (p>0.05). The rate of amblyopia, near deviation and amount of surgery were higher in group 2 cases (p<0.05). Between group 3 (n=64) and group 4 subjects (n=20), no significant differences were detected in terms of gender, surgical age, refraction, amblyopia, anisometropia, preoperative deviation angles, the number of symmetric and asymmetric surgeries, the amount of surgery, or postoperative binocular vision (p>0.05). The average postoperative follow-up period was 15.41±19.93 months (range, 6-98 months) in group 3 cases and 40.45±40.06 months (range, 6-143 months) in group 4 cases (p=0.000). No significant difference was detected in the amount of deviation corrected per 1 mm of surgical procedure between the successful cases in the symmetric and asymmetric groups (p>0.05).

Conclusion:

Symmetric or asymmetric surgery may be preferable in patients with infantile esotropia according to the clinical features. It is necessary for every clinic to review its own dose-response results.

Medial rectus muscle elongation, a technique to treat very large-angle esotropia

PURPOSE

The purpose was to describe the medial rectus muscle elongation (MRE) procedure to treat very large-angle esotropia (ET) with surgery on a lower number of muscles.

METHODS

Twenty patients with very large-angle ET (more than 70 PD) underwent the MRE procedure. In the MRE procedure, the muscle was split longitudinally into three parts. The wider central part was sutured with 6/0 vicryl and disinserted. The distal end of the peripheral parts (still attached to the original insertion), 7-9 mm away from the insertion, was sutured to the proximal end of the central part. At the end of the procedure, the distance of the anastomosis site from the insertion was named as the final elongation. The dose-response effect of the final elongation was calculated in bilateral MRE cases. The mean of the dose-response effect, obtained in the binocular surgery group, was used in the monocular surgery group to calculate the resection effect of lateral rectus (LR) muscle.

RESULTS

Eleven patients underwent bilateral MRE and nine patients underwent unilateral MRE and LR muscle resection. The mean preoperative far and near deviation was 94.10 ± 19.33 PD. The mean postoperative deviation was 14.60 ± 18.07 PD for far and 14.50 ± 18.23 PD for near deviation. In bilateral MRE cases, the mean dose-response effect of the elongation was 5.53 ± 0.67 PD/mm for far and 5.58 ± 0.69 PD/mm for near deviation. The mean LR muscle resection effect was 6.41 ± 1.99 PD/mm for far and 6.28 ± 1.93 PD/mm for near deviation.

CONCLUSION

The MRE procedure seems an acceptable method to treat very large-angle ET with surgery on a lower number of muscles.

Combining rectus muscle recessions with a central tenectomy to treat large-angle horizontal strabismus

PURPOSE

To report the effectiveness of incorporating a central tenectomy on the recessed rectus muscles when treating large-angle horizontal deviations.

METHODS

Patients undergoing recession and central tenectomy from March 2010 to January 2013 were prospectively enrolled. The procedure entails making two longitudinal incisions, each 4 mm, on the muscle adjacent to sutures made during the recession procedure. With recession complete and muscle sutured to the sclera, the central flap (with approximately one-third of the insertion width) is excised. The following variables were analyzed: expected correction (according to surgical dose tables), achieved correction (preoperative deviation minus postoperative deviation), and tenectomy effect (achieved correction minus expected correction).

RESULTS

A total of 16 horizontal rectus muscles of 16 eyes of 12 patients were included, 8 with exotropia and 4 with esotropia. No cases of significant limitation in duction in the field of the recessed muscle occurred. In all patients, the median achieved corrections at distance (55(Δ)) and at near (53.5(Δ)) were significantly higher than the median expected corrections (45(Δ) for both distance and near [P = 0.002]). The postoperative deviations at distance and near were lower in the unilateral surgery group (n = 8; statistically significant only for near deviation). The tenectomy effects in the esotropia group for both distance and near were more pronounced than those of the exotropia group (although not statistically significant).

CONCLUSIONS

In our patients central tenectomy of the recessed rectus muscles increased the effect of recession procedures without limiting ductions. There were possible greater effects in esotropia patients and recession-resection procedures.