A Clinical Application Research Based On UBM And Histological Analysis Of The Levator Muscle To Assess Moderate Ptosis Surgical Correction Results

BackgroundPtosis is a common condition in cosmetic surgery and ophthalmology.It is characterized by drooping of the upper eyelid,covering the pupil,and can have a significant impact on the aesthetic and psychological well-being of the patient.The most common and effective treatment is surgery,which is used to strengthen the upper eyelid by augmenting the upper eyelid muscle or replacing it with other tissues to improve the position of the upper eyelid margin when opening the eyes,exposing the pupil,improving visual function and improving appearance.Due to individual patient differences,the choice of procedure is currently based on the degree of preoperative ptosis and the strength of the levator muscle.However,the process of measuring preoperative ptosis and levator function is usually based on the experience of the surgeon and is subject to a number of subjective factors,which are inaccurate and lacking in quantifiable indicators that can be quantified by impact studies or histological analysis.The search for more accurate and less artificially biased tests for evaluating surgical outcomes is therefore a new direction of research on the topic of ptosis.Ultrasound biomicroscopy(UBM)is a non-invasive examination of the eyeball and eyelid in ophthalmology.There have been some reports of the use of UBM to assess the thickness of the levator muscle and to grade ptosis,but no studies have compared preoperative measurements with postoperative improvement to investigate the correlation and to guide the choice of procedure.Some studies have also investigated the impact of pathological changes in the upper eyelid muscle and surrounding tissues on the etiology of ptosis,using pathology of the upper eyelid tissue as a starting point.However,as the material basis in the correction of ptosis by levator shortening,the histological examination of the levator muscle to investigate the causes of postoperative strength changes and the intrinsic association with corrective outcomes has not been reported.This is an issue that needs to be investigated in the treatment of ptosis.ObjectiveIn addition to the conventional measures,preoperative UBM imaging and intraoperative histological staining were applied to investigate the effect of different preoperative levator muscle thicknesses and different muscle fiber densities on the outcome of correction.It has also been used to evaluate the effectiveness of the treatment of moderate ptosis using the levator shortening procedure and to predict postoperative improvement.It provides more standard and reliable criteria for the selection of the procedure and prognostic analysis,and serves as a guide in the diagnosis and management of moderate ptosis.MethodsA total of 38 patients(45 eyes)with moderate congenital ptosis diagnosed who underwent shortening of the levator palpebrae muscle at the Department of Plastic and Reconstructive Surgery,First Hospital of Jilin University from August 2020 to September 2022 were reviewed for the study.Based on the results of the preoperative UBM examination,the mean value of 0.56 mm was taken as the threshold value and the patients were divided into two groups,A and B.The improvement in MRD1 were compared to verify the correlation between preoperative UBM measurements of levator muscle thickness and postoperative correction.The excess levator muscle flap removed intraoperatively was also examined histologically to investigate the differences in the histology of the levator muscle between patients and its effect on the amount of postoperative improvement in muscle strength.The patients were followed up for 6months after surgery and the data were statistically analyzed.ResultsThere were no statistically significant differences between the different groups in the 38 patients(45 eyes)included in this study in terms of preoperative age,gender,eye category,MRD1 and levator muscle strength.There was a statistical difference(p<0.05)between groups A and B in terms of MRD1,the amount of improvement in muscle strength and the degree of short-term postoperative eyelid closure incompleteness at 6months postoperatively.A correlation was found between the thickness of the levator muscle obtained by UBM and the postoperative outcome,with patients with greater preoperative levator muscle thickness having better results with levator shortening;the amount of improvement in muscle strength =-3.86 +(0.09 x percentage of myofibroblast cross-sectional area)was approximated by statistical analysis based on histological examination of the intraoperative levator flap.A linear relationship(p<0.001)was found between the density of the levator muscle and the postoperative improvement in muscle strength.Conclusions1.UBM imaging provides a visual measurement of the thickness of the levator muscle,providing a more accurate and reliable test for preoperative procedure selection and postoperative assessment of improvement,and is a useful guide to levator-related procedures for the treatment of ptosis.2.The thickness of the preoperative levator muscle correlates with the outcome of the levator shortening,and patients with greater thickness have better results with levator shortening to correct moderate ptosis.3.The improvement in muscle strength after shortening of the levator palpebrae muscle is positively correlated with levator muscle fiber density,and a quantified linear numerical relationship enables the prediction of postoperative levator muscle strength improvement.