Ultrastructural changes of myotendinous nerve endings following recession or resection procedures of extraocular muscle surgeries in cats

Postoperative changes in spatial localization following exotropia surgery

PURPOSE

To measure changes in spatial localization following exotropia surgery using a computer touch-screen method of measurement.

METHODS

Enrolled in the study were 60 exotropia patients, all of whom had undergone corrective muscle surgeries under general anesthesia: 37 patients had undergone unilateral lateral rectus or bilateral lateral rectus muscle recession procedures (recession group) and 23 patients had undergone unilateral lateral and medial rectus muscle resection (R&R), or unilateral medial rectus resection only (resection group). We evaluated spatial localization by having patients point to targets on a computer touch-screen before surgery, and 1 day and 1 month after surgery. The pointing error, Δp, is defined as the difference between the actual location of the target and the pointed-to location of the target by unsigned value, was recorded as the mean of five tests. We compared the extent of postoperative changes in Δp between the two groups.

RESULTS

The mean Δp before surgery did not differ statistically between the two groups (p = 0.93). One day after surgery, however, the postoperative change in Δp of the resection group compared with that of the recession group (2.0 ± 0.7° and 0.4 ± 0.5°, respectively) was significant (p = 0.01 and p = 0.86 respectively).

CONCLUSIONS

The ability for spatial localization is decreased in patients immediately following medial rectus resection, but is regained by 1 month following surgery.

Postoperative convergence after recovery from general anesthesia in exotropia surgery

PURPOSE

To compare eye position at the end of surgery under general anesthesia with strabismic angles on postoperative day 1 in exotropia surgery.

METHODS

Seventy-eight patients between 3 and 58 years of age who had undergone surgery were divided into two groups (group A = 46 patients with bilateral rectus recession, group B = 32 patients with surgery that included medial rectus resection). Strabismic angles were measured at the end of surgery under general anesthesia using the Hirschberg test and the alternate prism cover test was performed on postoperative day 1.

RESULTS

Mean strabismic angle was 3.15 prism diopters (PD) under general anesthesia and -6.78 PD on postoperative day 1 in group A and -0.31 and -0.37 PD, respectively, in group B. Mean postoperative convergence was 9.93 PD in group A and 0.06 PD in group B, and the differences were statistically significant (P < .001).

CONCLUSION

All patients receiving lateral rectus recession showed approximately 10 PD of convergence. Those who received surgery that included medial rectus resection showed much less convergence and a tendency to be the same as at the end of surgery on postoperative day 1.