Surgical treatment of familial absence of the inferior rectus muscle

Congenital anomalies of inferior rectus and its surgical outcomes

Congenital inferior rectus hypoplasia and aplasia is a rare abnormality of the extraocular muscles, and it is the second most common after superior oblique muscle aplasia. It has been reported either in isolation or with coexisting ocular or systemic associations. We describe here cases of inferior rectus hypoplasia/aplasia, their clinical features, and surgical approach to achieve satisfactory outcomes. We retrospectively reviewed medical records from January 2009 to December 2020 of patients with vertical strabismus due to inferior rectus hypoplasia/aplasia at a tertiary eye care center. Those who underwent surgical intervention with an adequate follow up postoperatively were included in the study. Three patients who presented with congenital hypertropia and diagnosed of inferior rectus aplasia/hypoplasia and who underwent strabismus surgery were identified. Diagnosis was based on clinical examination and orbital imaging. Coexisting horizontal deviation was present in two patients. None of the patients had any other ocular, cranial, or systemic anomalies. All patients had isolated inferior aplasia/hypoplasia with normal other extraocular muscles on orbital imaging. Intraoperatively, ipsilateral superior rectus was tight in all patients. All underwent ipsilateral superior rectus recession, whereas two patients with large vertical strabismus required additional inferior oblique anteronasal transposition in the same eye. Satisfactory outcomes were achieved in all three patients without the need for resurgery. Moderate to large vertical A pattern strabismus and limitation of infraduction are common clinical findings. Orbital imaging helps not only in diagnosis but also in surgical planning. Weakening of antagonist superior rectus with anteronasal transposition of inferior oblique not only gives good surgical outcomes but also avoids potential complications related to vertical transposition of either horizontal rectus muscle.

Congenital dysplasia involving both medial and inferior recti: clinical features and surgical outcomes

AIM

To investigate the clinical features and surgical outcomes of congenital dysplasia involving both inferior recti (IR) and medial recti (MR) muscles.

METHODS

A retrospective review was conducted including cases of simultaneous congenital dysplasia of IR and MR that were diagnosed and surgically treated at the Zhongshan Ophthalmic Center, Sun Yat-sen University, China, from July 2009 to November 2019. Ocular motility, ocular alignment at distance (6 m) and near (33 cm) by prism alternating cover test and stereoacuity were assessed in all patients before and after surgery.

RESULTS

A total of five patients (four males and one female; three with right eye and two with left eye congenital dysplasia) were included in this review. The patients ranged in age from 10 to 42y (21±13.4y). The main clinical findings were hypertropia and exotropia of the affected eye, along with motility limitations in adduction and depression. Lateral rectus (LR) recession/transposition combined with IR resection was performed in one case. Two scheduled surgeries were performed in four cases, with one involving superior rectus recession and IR resection and the others LR recession and MR resection. Mean±SD pre-surgical exotropia of 51.0±31.11 prism diopter (PD) and hypertropia of 29.20±7.12 PD in the primary position were decreased to 3.6±12.90 and 3.2±10.09 PD, respectively, at two years after surgery, with a success rate of 60% and an under-correction rate of 40%.

CONCLUSION

The main clinical features associated with simultaneous MR/IR congenital dysplasia are hypertropia and exotropia of the affected eye along with motility limitations in adduction and depression. Scheduled two-stage surgeries achieved a success rate of 60%.

Managing Hypoplasia of the Inferior Rectus Muscle by Inferior Oblique Anterior Transposition in Children

Congenital hypoplasia or aplasia of the inferior rectus muscle is an uncommon condition. The authors present two pediatric patients with hypoplasia of the inferior rectus muscle treated by inferior oblique anterior transposition. The long-term follow-up outcomes of eye position and stereopsis acuity development were favorable. [J Pediatr Ophthalmol Strabismus. 2017;54:e50-e53.].

Resection and anterior transposition of the inferior oblique muscle for treatment of inferior rectus muscle hypoplasia with esotropia

Purpose

To report a case of inferior rectus muscle hypoplasia with esotropia, which was treated successfully by resection and anterior transposition of the inferior oblique muscle.

Observations

A 1-year-old boy presented with esotropia. He had esotropia of 15–30° and intermittent left hypertropia. At the age of 3 years, the alternate prism cover test showed esotropia of 35Δ and left hypertropia of 25Δ. Magnetic resonance imaging of the orbit revealed left inferior rectus muscle dysgenesis. Strabismus surgery was performed and a hypoplastic left inferior rectus muscle was identified. We performed bilateral medial rectus muscle recession, and resection and anterior transposition of the left inferior oblique muscle. Nine months after the surgery, the patient had esotropia of 8Δ and left hypertropia of 6Δ.

Conclusions and importance

Resection and anterior transposition of the inferior oblique muscle is useful for hypoplasia of the inferior rectus muscle accompanied by horizontal strabismus.