Postoperative Angle Of Deviation Research Articles

Effect of Muscle Relaxants on Short-term Results of Exotropia Surgery: A Focus on Resection Procedures

PurposeWe investigated the effect of muscle relaxants (atracurium) on the outcomes of intermittent exotropia surgery under general anesthesia, with a focus on resection procedures.MethodsThirty four patients who underwent recession and resection (R&R) were divided into two groups: atracurium usage (group A, n=18) and no atracurium usage (group B, n=16). Patients were divided into two subgroups according to the amount of resection of the medial rectus (MR): less than 5 mm (group 1, n=13) or 5 mm and greater (group 2, n=21). Deviation angles were compared between groups and subgroups. Surgical outcome was defined as successful if distant deviation angles were equal to or less than 10 prism diopters.ResultsThe overall postoperative deviation angles did not show statistically significant differences between groups A and B. However, in patients with larger MR resections (≥ 5 mm), the 1 week postoperative distant deviation was significantly larger in group A (1.8±2.6 PD) than in group B (-1.6±4.6 PD, p=0.048 by t-test). The overall undercorrection rate at 3 months postoperatively for group A was 16.7%, which was higher than that of group B (6.3%), and the difference was even larger in subgroups with larger MR resections (≥ 5 mm): 18.2% in group A and 0% in group B.ConclusionsPatients who underwent R&R procedures under general anesthesia with a muscle relaxant tended to be less corrected than those without muscle relaxant, especially in the early postoperative period and with a larger MR resection equal to or greater than 5 mm. However, there was no significant difference in the later postoperative period.

The Clinical Features of Patients with Early Recurrence and with Orthophoria After Intermittent Exotropia Surgery

Purpose: To analyze the clinical features of patients with exodeviation of more than 15 prism diopters (PDs) within one month and with orthophoria over three years after surgical correction of intermittent exotropia. Methods: The early recurrence group consisted of patients with a final distance and near exodeviation more than 15PDs within one month after surgical correction of intermittent exotropia. The surgical success group was defined as patients with orthophoria over three years after surgical correction of intermittent exotropia. Sex, age at onset and surgery, office control status, refraction status, A-V pattern, preoperative and postoperative angles of ocular deviation, binocular sensory status, and the presence of diplopia on postoperative one day were retrospectively investigated and compared between these two groups. Results: Out of a total of 68 patients, early recurrence occurred in 33 patients, and success was achieved in 35 patients. Factors including sex, age at onset and surgery, office control status, and diplopia on postoperative one day did not differ between the two groups. Preoperative near-angles of ocular deviation, A-V pattern of strabismus, preoperative stereopsis, and the range of postoperative overcorrection contributed to early recurrence. Conclusions: Factors related to early recurrence were larger preoperative near-angles of ocular deviation, presence of A-V pattern, poor preoperative stereopsis, and a smaller amount of overcorrection on postoperative day 1. J Korean Ophthalmol Soc 49(7):1108-1113, 2008

Factors Affecting the Surgical Outcome of Primary Exotropia

Aims To identify the predictors for motor outcome and response to surgical treatment of primary exotropia. Setting Taunton and Somerset Hospital, Somerset, United Kingdom. Study type Retrospective analysis of the surgical treatment of primary exotropia performed in our department over a period of 12 years from April 1991 to May 2003. Methods Case-notes of the patients who had surgical treatment for primary exotropia for the specified period were identified by a hospital computer database (MDI coding). All case-notes were reviewed and the following data were recorded and used for statistical analysis: age at the time of surgery, type and severity of exotropia, presence of amblyopia, AV pattern and vertical deviation, the level of stereopsis, type of surgery, and motor and cosmetic results. The surgical outcome was determined as good motor outcome if tropia was within 10 PD of orthotropia. The response to surgery was derived from the difference between the preoperative and postoperative angle of deviation for distance per amount of muscle surgery in millimetres. Results A total of 124 cases were included in the study. Good motor outcome was achieved in 83 (67%) cases. There was a positive correlation between the preoperative angle of deviation at distance and dose response to surgery (r = 0.6 and p < 0.001) and a negative correlation between average corrected visual acuity and response (r = −0.21 and p = 0.025). There was a statistically significant negative relationship between preoperative stereopsis and response to surgery (p = 0.02). Conclusions Surgical treatment for exotropia is effective and the dose response is correlated to the preoperative angle of deviation and average visual acuity. Poor or no preoperative stereopsis was associated with better response to surgery.

Adjustment of the surgical nomogram for surgery on slipped extraocular muscles

A slipped muscle is an underdiagnosed complication of strabismus surgery. Surgery necessitates intraoperative diagnosis, measurement, and resection of the empty sheath. We analyzed the results of empty sheath surgery for slipped medial and lateral rectus muscles in a large cohort of patients. Eighty-five patients who underwent empty sheath surgery at a secondary referral center by a single strabismologist were included in the study. We retrospectively analyzed the preoperative and postoperative change in angle of deviation 6 weeks after surgery. All cases were reoperations in which an unexpected or unsatisfactory outcome followed primary surgery. Consecutive exotropias with slipped medial rectus muscles were noted in 68 patients. There were 17 esotropia cases with lateral rectus muscles slip, of which 2 were consecutive exotropias that became consecutive esotropias. Bilateral medial rectus muscle slips were found in 6 patients with consecutive exotropias. Adjustable suture surgery was performed in 27 patients. Resection of the empty sheath of the slipped medial or lateral rectus muscle with advancement to the original site of insertion was done in all cases; in addition, the antagonist muscle was recessed only if it was tight. The total muscle advancement was calculated in millimeters from the total amount of sheath resected, muscle advanced, and the antagonist recessed. The greater the preoperative deviation, the more surgical muscle advancement was required and the greater the change in postoperative angle of deviation. Mean change in angle of deviation was 3.13(delta) for each millimeter of muscle advancement (median = 3.00, SD = 1.72). The diagnosis of slipped muscle should be confirmed during strabismus surgery. The empty sheath was measured, resected, and the muscle advanced to the original site of insertion. An approximate 3(delta) change in angle of deviation was observed for every millimeter of muscle of advancement. For very large and very small deviations, surgeons should modify this to an accustomed measurement dictated by their experience.

Adjustable and non-adjustable strabismus surgery: a retrospective case-matched study

Adjustable suture strabismus surgery was introduced to improve results in unpredictable strabismus cases. However, its usage is increasing and in some centres is routine. The present authors propose that the routine use of the adjustable suture technique can only be justified if it can be shown to confer an advantage to the patient. In a retrospective analysis of matched data, they compared the results of their adjustable with non-adjustable strabismus surgery. The adjustable suture procedures performed during a 5-year period, on non-thyroid eye disease patients, were matched to non-adjustable cases according to the type and aetiology of strabismus and the magnitude of deviation. Pairs were matched as closely as possible according to age and strabismus surgery history. All cases were incomitant. The surgical results of the two groups were analysed with regard to the pre-operative and post-operative angles of deviation, the post-operative drift, and a successful outcome, pre-defined by carefully selected criteria. Twenty-six cases were analysed in each of the two groups. Mean pre- and post-operative angles of deviation showed no significant difference between the two groups. ‘Success’ rates were 81% in the adjustable group and 88% in the non-adjustable group. Given that the success rate of the two techniques is similarly high, a much larger study is required to detect a difference in results, with statistical significance. The authors conclude that there is currently insufficient evidence that patients, without thyroid eye disease, benefit from the longer and potentially uncomfortable procedure of adjustable suture strabismus surgery to support its rapidly growing use and that a prospective randomised controlled trial is indicated.

The Effect of Preoperative Convergence Exercises on the Surgical Outcome of Primary Exotropia

In a retrospective study of 89 patients with exotropia, the authors investigated the influence of active convergence exercises in the postoperative angle of deviation and found that convergence exercises do not increase the incidence or the size of the esodeviation post-operatively.