J Korean Ophthalmol Soc.  2001 Aug;42(8):1210-1219.

The Effect of Chemical Myectomy using Doxorubicin Delivered by Osmotic Pump on Eyelid Skin Necrosis

• Lee JB
• Lee TS

Abstract

PURPOSE: Direct injection of doxorubicin into the eyelids results in permanent loss of muscle fiber and it is considered an attractive nonsurgical method in essential blepharospasm therapy. However, necrosis of skin overlying orbicularis oculi muscle is the most serious side effect of this therapy. The purpose of this study is to determine the effect of doxorubicin delivered by osmotic pump which release doxorubicin slowly, and to evaluate the degree of overlying skin injury following chemical myectomy.
METHODS
Thirty three rabbits were assigned to three groups according to the doxorubicin concentration. The first group received direct injections of 0.5 mg doxorubicin diluted in 0.1 ml of saline in the right lower eyelid. and osmotic pump was inserted into the left lower eyelid which contained 0.5 mg doxorubicin in 0.1 ml of saline. The second group received 1 mg doxorubicin and the third group received 2 mg doxorubicin. Eight weeks after injection, the eyelids were assessed for the degree of muscle fiber loss microscopically. For the evaluation of functional change of muscle, an EMG study was carried out.
RESULTS
Skin necrosis developed in all rabbits except for one which received injection of 0.5 mg doxorubicin. Skin necrosis appeared earlier in the direct injection group. The duration of skin necrosis was shortened at lower concentrations(0.5 mg, 1.0 mg) with a pump delivery(P<0.05). But there was no statistical differences in the 2.0 mg concentration. The size of necrosis was much smaller in rabbits using pump delivery than those of direct injection group in high doxorubicn concentrations(1.0 mg, 2.0 mg)(P<0.05). The total size of muscle fiber was decreased after a doxorubicin injection. There was no statistical difference between the direct injection group and the pump group(P<0.05). The similar effect on the muscle was noted regardless of the slow release of the doxorubicin into the muscle. Light microscopic study demonstrated destructive change of muscle and it was replaced by connective tissues. Electron microscopic study showed destruction of micro-architecture of muscle fibers. Functionally, in EMG study, there was no motor activity in the injection area. But some motor unit potentials appeared in the periphery of skin necrosis site.
CONCLUSIONS
These results suggest that the osmotic pump may be used as an effective adjuvant in preventing skin necrosis in blepharospasm treatment.

Keyword

Blepharospasm; Doxorubicin; Osmotic pump

MeSH Terms

Blepharospasm
Connective Tissue
Doxorubicin*
Eyelids*
Motor Activity
Necrosis*
Rabbits
Skin*
Doxorubicin