Stability of Y-splitting procedure combined with hang-back  recession of the rectus muscle in rabbit eyes.
BACKGROUND
The Y-splitting procedure has been used both to treat up-shoots and down-shoots in Duane syndrome, and as a substitute for posterior fixation suture. The Y-split is often performed in conjunction with a hang-back recession when a large amount of recession or an adjustable suture is necessary. Herein, we evaluated the stability of Y-splitting hang-back recession in the rectus muscle.


METHODS
Under general anesthesia, a 5-mm hang-back recession of the superior rectus muscle (SR) with Y-splitting was performed in ten eyes from ten rabbits (hang-back group). A conventional recession was performed in the SR of the fellow eye (control group). Six weeks after the procedure, the distance between the original insertion and the recessed SR (recession amount) and the width between the nasal and temporal halves of the SR were measured. These values were compared to the measurements taken at the time of surgery.


RESULTS
The hang-back group had a significantly larger forward displacement than the control group (P < 0.001 for both the nasal and temporal halves). The width change between the nasal and temporal halves was also significantly larger in the hang-back group (4.94 ± 1.32 mm) than in the control group (1.14 ± 0.60 mm, P < 0.001). Additionally, the Y-configuration appeared to be more collapsed in the hang-back group than in the control group.


CONCLUSIONS
Y-splitting of the rectus muscle may be unstable when it is combined with a hang-back recession. Surgeons should consider this possibility when performing Y-splitting procedures.
Soh-Eun
SE
Ahn
Ji-Yun
JY
Han
Seung-Hyun
SH
Kim
Yoonae A
YA
Cho
Young-Woo
YW
Suh
D000818:Animals; D004370:Duane Retraction Syndrome / Q000601:surgery; D009801:Oculomotor Muscles / Q000601:surgery*; D013508:Ophthalmologic Surgical Procedures; D011098:Polyglactin 910; D011817:Rabbits; D012590:Sclera / Q000601:surgery; D013285:Strabismus / Q000601:surgery; D013536:Suture Techniques; D013537:Sutures
D011098:Polyglactin 910