Morphological structure of the levator muscle in congenital and acquired ptosis of the upper eyelid

AIM: To examine the relationship between the morphological structure of the levator in congenital and acquired ptosis based on dynamometric data and histological research.

MATERIAL AND METHODS: Dynamometric and histological examination of the morphological structure of the levator in congenital and acquired ptosis of the upper eyelid was conducted. Twenty-seven fragments obtained during the operation to eliminate blepharoptosis were studied.

RESULTS: With congenital ptosis of the upper eyelid, the average values of SS and fatigue were 1.06±0.39 g and 1.88±0.89 g, respectively; with acquired ptosis, the average values of SS and fatigue were 1.47±0.66 g and 2.31±0.91 g, respectively (p <0.05). All the biopsies were divided into two groups. Group 1 included biopsies of 16 patients with congenital ptosis (n=16), and group 2 included 11 levator fragments with acquired ptosis. Macroscopic examination revealed greater levator fragment lengths in the acquired ptosis group than in the congenital ptosis group: 2.33±1.32 mm and 1.22±0.34 mm, respectively (p ≤0.05). The levator fragments differed in color and had denser elastic consistency in the acquired ptosis group than in the congenital ptosis group. The histological picture in congenital ptosis (n=11) was an overgrowth of the fibrous–adipose tissue, and five biopsies showed an overgrowth of fibrous tissue with signs of protein dystrophy. In levator biopsies with acquired ptosis, seven biopsies with aponeurotic ptosis of the upper eyelid were characterized by the overgrowth of fibrous–adipose tissue. The first biopsy (myasthenic ptosis of the upper eyelid) demonstrated the predominance of adipose tissue, with scattered bundles of striated muscle fibers and areas of connective tissue with bundles of smooth muscle fibers. In the remaining three biopsies, fragments of adipose tissue with signs of edema and hyperplasia were identified.

CONCLUSION: Congenital ptosis is characterized by relatively low strength and rapid fatigue of the upper eyelid levator, higher occurrence of fibrous–adipose tissue, and fibrous tissue proliferation. Acquired ptosis is characterized by average strength and fatigue. In the acquired ptosis group, histological data indicate an equal ratio of fibrous–adipose and adipose tissue growth. These results can be used in the diagnosis of various forms of ptosis and selection of an effective method for surgical correction for this pathology.