Clinical Study Of Classified Inferior Oblique Muscle Recession Surgery For Treatment Of IOOA

Objective:To investigate the therapeutic effect of classified inferior oblique muscle recession surgery.Compared with the traditional inferior oblique muscle cutting,partial resection,and recession,the postoperative complications were observed such as residual vertical deviation,anti-elevation syndrome AES etc.Methods:The analysis of 67 strabismus cases?88 eyes?with inferior oblique muscle overaction?IOOA?were been done in the Fourth Zhangjiakou Hospital from January 2015 to September 2017.The patients were randomly divided into 2 groups which would be received by the surgery of inferior oblique muscle cutting,partial resection and classified recession.Postoperative follow-up time was 3¹0 months with an average of 6 months.The regular eye examination included head position,visual acuity,intraocular pressure,fundus,B ultrasound scan,optometry under dilated pupil,prism degrees,binocular visual function,eyeball movements,muscle pull test and imaging examination?option?.Quantify the strength of inferior oblique muscle of patients were completed with that before surgery.In this study,the classification method of inferior oblique muscle function was referred from Hunter and Parks.[1]Surgical design was performed according to the degree of inferior oblique muscle force as followed.Control group:?1?inferior oblique muscle overaction+,inferior oblique muscle amputation;?2?++,3mm muscle excision;?3?+++,5mm muscle excision.?4?++++,8mm muscle excision.For those who have more than 25^?vertical deviation,the inferior rectus recession.Or the surgery was designed to strengthen the force of superior oblique muscles in suffered eye.Experimental group:?1?inferior oblique muscle overaction+,the inferior oblique muscle recession position at 4 mm posterior and 2mm temporal to the inferior rectus temporal point of attachment.?2?++,recession position at 4 mm posterior to the inferior rectus temporal point of attachment.?3?+++,recession position at 1² mm posterior to the inferior rectus temporal attachment point.?4?++++,recession position at margin of the inferior rectus temporal attachment point.The posterior margin of the inferior oblique muscle was sutured at 5mm posterior to the anterior fixed point.In terms of the cases with more than 25^?vertical deviation,the same surgery was performed.Efficacy evaluation:according to Hills standard:^[2]Cured:the original position of vertical oblique angle<4^?,no compensatory head position,no inferior oblique muscle overaction.Improved:the vertical deviation between 5¹0^?,the improved compensation head position and the partially hyperactive inferior oblique muscle.Null and void:the original vertical oblique Angle>10^?,the obvious compensatory head position,inferior oblique muscle hyperactivity not significantly improved.The preoperative and postoperative vertical deviation and the force of inferior oblique muscle were compared between the two groups.The surgery complications were also recorded and compared postoperatively.Results:1.Basic data analysis:the 67 patients enrolled in this study were 6 to 34years old,with an average age of 17 years.Both eyes were suffered in 21patients.They were randomly divided into group A?32 patients including 11patients with bilateral suffered eyes?and group B?35 patients,including 10patients with bilateral suffered eyes?.The two groups of patients were randomly assigned.The preoperative examination was performed under the same examination equipment and the surgery was completed by the researcher himself to guarantee that the data can be analyzed comparably.The number of cases,eyes,diseased eyes of the two groups were not statistically difference,P>0.05.2.Preoperative examination results and the ways of surgery:Group A:21 monocular cases including inferior oblique muscle overaction+,8 patients;++,7 patients;+++,6 patients;binocular symmetry,5cases including++3 cases and+2 cases;asymmetry,6 cases with one eye+and contralateral eye+.Group B:25 monocular cases including inferior oblique muscle overaction+,13 patients;++,6 patients;+++,6 patients;binocular symmetry,5cases including++1 cases and+4 cases;asymmetry,5 cases with one eye+and contralateral eye++4 cases and one eye+and contralateral eye+++1 cases.3.Preoperative data in group A:In the original eye position the average vertical deviation?14.7±3.2?prism diopters?PD?;postoperative mean correction?12.7±2.1?PD.In group B,the average vertical deviation?14.5±4.1?PD,the postoperative average correction?10.4±2.6?PD;The residual vertical deviation in group A was average?2.3±1.1?PD;the residual vertical deviation in group B?4.2±1.4?PD.Preoperatival deviation of the two groups were not statistically difference,P>0.05,The deviation difference of preoperative and after surgery with statistical significance?P<0.05?both of the two groups.Therapeutic effect obvious both of the two groups.The deviation of after surgery difference of interblock with statistical significance?P<0.05?,therapeutic effect of the experiments group were superior to the control group.4.Cure rate:According to Hills standard:In group A,25 patients were cured after surgery and the cure rate was 78.1%.The improved case was 5,which the rate was the 15.6%.The inefficiency rate was 5.7%in which there were 2 cases.In group B,19 cases were cured occupying the 54.2%and 9cases were improved with rate of 25.7%.The inefficiency rate was 20.0%n which there were 7 cases.the difference of cured cases with statistical significance?P<0.05?5.There were 3 cases with inferior oblique muscle overaction+1 cases overaction++in group A.Nevertheless,in group B,there were+10 cases and++2 cases.No+++cases were observed in both groups.However,3 cases in group B.Anti-elevation syndrome?AES?did not occurred after surgery.Conclusion:The classified surgery of inferior oblique muscle is an effective method for the treatment of IOOA.This method can be used to correct the vertical deviation as many as?12.7±2.1?PD?the original eye position?averagely.Furthermore,the postoperative residual vertical deviation and oblique muscle hyperfunction were significantly less than those of the control group.No anti-elevation syndrome was observed postoperatively.Both the therapeutic effect and the incidence of complications in the experiments group were superior to the control group.