Clinical characteristics and surgical outcomes of isolated inferior rectus palsy

Licheng Fu,Binbin Zhu,Jianhua Yan

doi:10.1186/s12886-021-02121-z

Abstract

AimAs isolated inferior rectus muscle (IRM) palsy represents a rare clinical entity, very limited information is available on this condition. The aim of this report was to elucidate the etiology, clinical characteristics and surgical outcomes of isolated IRM palsy.MethodsIsolated IRM palsy cases who underwent surgical treatments at the Zhongshan Ophthalmic Center, Sun Yat-sen University, China over the period from January 2008 to June 2019 were reviewed retrospectively. Data evaluated from these cases included their etiology, ocular alignment, ocular motility, surgical procedures and surgical outcomes.ResultsA total of 61 patients (40 males, 21 females) were included in this review. Their mean ± SD age was 27.21 ± 16.03 years (range: 2 to 73 years). In these cases, 32 (52.5%) involved traumatic injury, 28 (45.9%) congenital hypoplasia or absence of inferior rectus and 1 (1.6%) with thyroid ophthalmopathy. The right eye was affected in 33 patients (54.1%), the left in 24 patients (39.3%), and both eyes in 4 patients (6.6%). The main clinical presentations consisted of hypertropia of the affected eye, motility limitation in abduction and depression and incyclotropia. After treatment consisting of various surgical approaches, including muscle repair or resection of the affected inferior rectus, recession of ipsilateral superior rectus, elongation of contralateral superior oblique and partial transposition of the horizontal rectus, the isolated IRM palsy was rectified in 49 patients (80.4%) with one surgery, while 11 cases (18.0%) required two surgeries and 1 case (1.6%) needed three surgeries. Finally, 52 patients (85.2%) showed a complete recovery, 6 (9.9%) improved and 3 (4.9%) experienced a surgical failure.ConclusionThe main etiologies of isolated IRM palsy involved traumatic injury and developmental events. Overall, surgical outcomes of the various approaches employed were quite effective.

Highlights

Isolated inferior rectus muscle (IRM) palsy without involvement of other muscles supplied by the oculomotor nerve is very rare [1,2,3,4], with only a few reports in the literature describing this condition
Unlike that of previous reports, we found that an etiological diagnosis of IRM palsy could be achieved in all patients after conducting a detailed clinical and orbital imaging evaluation
The right eye was affected in 33 patients (54.1%), the left in 24 (39.3%) and both eyes in 4 patients (6.6%)

Summary

Introduction

Isolated inferior rectus muscle (IRM) palsy without involvement of other muscles supplied by the oculomotor nerve is very rare [1,2,3,4], with only a few reports in the literature describing this condition. Fu et al BMC Ophthalmology (2021) 21:422 From this limited review involving IRM cases, it is clear that pertinent clinical characteristics and surgical management of congenital and acquired IRM palsy are sorely lacking. Protocols for the treatment of this condition as well as its etiology need to be established Such informations will be required to resolve some of the clinical challenges with regard to the selection and implementation of appropriate surgical corrections of isolated IRM palsy after failure of conservative treatments. Ipsilateral IR resection with/without superior rectus (SR) recession produced satisfactory surgical outcomes in a large percent of these cases

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