Modified Nishida's procedure in management of unilateral isolated inferior rectus aplasia - A case report

Akila V Ramkumar; Sumita Agarkar; Swathi Mailankody

doi:10.4103/ijo.IJO_2344_20

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CASE REPORT

Year : 2021 | Volume : 1 | Issue : 2 | Page : 363-364

Modified Nishida's procedure in management of unilateral isolated inferior rectus aplasia - A case report

Akila V Ramkumar, Sumita Agarkar, Swathi Mailankody
Department of Paediatric Ophthalmology, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India

Date of Submission	21-Jul-2020
Date of Acceptance	02-Oct-2020
Date of Web Publication	01-Apr-2021

Correspondence Address:
Dr. Sumita Agarkar
Department of Paediatric Ophthalmology, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu
India

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijo.IJO_2344_20

Abstract

Inferior rectus aplasia is a rare cause of apparent inferior rectus palsy presenting as upward deviation of eye since birth. An ideal procedure to manage these cases should correct the deviation in primary gaze and improve motility of the eye. It has been managed in the past by full or partial tendon transplantation of horizontal recti muscles which poses a risk of anterior segment ischemia and is usually done in a staged manner. We report a case of inferior rectus aplasia confirmed preoperatively by imaging and successfully managed by a no split, no tenotomy method done in a single stage.

Keywords: Anterior segment ischemia, congenital strabismus, inferior rectus aplasia, modified Nishida technique, muscle transposition

How to cite this article:
Ramkumar AV, Agarkar S, Mailankody S. Modified Nishida's procedure in management of unilateral isolated inferior rectus aplasia - A case report. Indian J Ophthalmol Case Rep 2021;1:363-4

How to cite this URL:
Ramkumar AV, Agarkar S, Mailankody S. Modified Nishida's procedure in management of unilateral isolated inferior rectus aplasia - A case report. Indian J Ophthalmol Case Rep [serial online] 2021 [cited 2021 Apr 20];1:363-4. Available from: https://www.ijoreports.in/text.asp?2021/1/2/363/312373

Congenital absence of extraocular muscles is rare and is usually associated with craniofacial syndromes.^[1] Most commonly affected muscles are superior rectus and superior oblique followed by inferior rectus.^[2],[3] Isolated inferior rectus muscle aplasia is very rare and has been described in association with microcornea, microphthalmos and coloboma.^[2],[3]

We describe a case of isolated unilateral inferior rectus aplasia which was successfully managed surgically applying the modified no split, no tenotomy simple muscle transposition of horizontal recti along with superior rectus recession. This has been described in the past for abducens palsy by Nishida et al.^[4] We report a rare case describing the use of this principle for management of inferior rectus aplasia.

Case Report

An 8-year-old boy presented with history of upward deviation of left eye since birth. The best-corrected visual acuity was 20/20, N6 in right eye and 20/40, N6 in the left eye. Stereoacuity in left eye was over 600 seconds of arc. On cover test, he had 25PD of hypertropia with 12 PD of esotropia in left eye in primary position. Hypertropia of 12PD was measured in up gaze, increasing to 35 PD in down gaze. Ocular motility examination showed a -4 limitation of depression in the left eye which was more in abduction [Figure 1]. Anterior segment and fundus examinations were unremarkable. MRI of orbit revealed a thin, cord-like inferior rectus in the left eye suggestive of aplasia [Figure 2]a. A surgical correction in the left eye was planned.

Figure 1: Pre-operative 9 gaze montage showing left hypertropia in primary gaze with restricted depression

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Figure 2: (a) MRI orbit showing a normal right inferior rectus and an aplastic left inferior rectus. (b) Absent inferior rectus and abnormal vascular anastomosis from medial and lateral recti muscles seen on surgical exploration

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The intraoperative Forced Duction Test showed a tight superior rectus. During exploration of inferior rectus, no muscle structure could be identified. A vascular anastomosis involving the vessels from the medial and the lateral rectus was seen at the putative site of insertion of the inferior rectus [Figure 2]b. Exploration of the other recti revealed normal location and structure of the muscles. We proceeded with 6 mm recession of superior rectus. In addition we did modified Nishida's procedure^[4] on the horizontal recti. A 5-0 Polyester suture was passed through the inferior one-third of lateral and medial recti, 10 mm behind their insertion. Lateral and medial recti were fixed to sclera in the infero-temporal and infero-nasal quadrants respectively midway between horizontal rectus muscle insertion and inferior rectus insertion 12 mm behind the limbus. Postoperative period was uneventful.

At 6 months, the patient had a small overcorrection in primary gaze [Figure 3]. Visual acuity remained same. Stereoacuity of 400 seconds of arc was measured in left eye. Cover test showed a hypotropia of 6 PD and esotropia of 4 PD in the left eye. Infraduction improved to -2. There was a -1 limitation in elevation of the left eye.

Figure 3: Postoperative 9 gaze montage showing a left eye hypotropia of 6 PD BU with improved depression

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Discussion

Inferior rectus aplasia is rare and almost a third of patients have associated anomalies such as coloboma, microphthalomos and microcornea. Hence it is hypothesized that inferior rectus aplasia may be due to abnormal optic fissure closure during embryogenesis.^[3] One should keep an index of suspicion for congenital absence or hypoplasia of the muscle in cases with a large vertical tropia with limited motility since birth. As noted in our case, a preoperative orbital imaging is of immense value to avoid surprises on the table and helps in better surgical planning.

Surgical management of this entity has constantly evolved over the years. Ingham et al.^[5] used superior rectus recession alone, which did not completely resolve the hypertropia and hence required a secondary full tendon transposition. Vertical transposition of horizontal recti either full tendon or split tendon, near insertion of inferior rectus or the inverse Knapps procedure is the most commonly described procedure for inferior rectus aplasia. Taylor and Kraft^[2] were the first to describe the successful full tendon transposition as a primary procedure in a 2 year old boy with congenital inferior rectus absence. Same approach with successful results has been advocated by Guha et al.^[6] in a recent publication. Other techniques such as inferior oblique anterior transposition and superior rectus transposition have also been described.^[2],[7],[8] A major concern in transposition procedures is the increased risk of anterior segment ischemia as anterior ciliary vessels supplying inferior rectus may be absent or abnormal as seen in our case. In such a situation when both the horizontal muscles are transposed, the anterior circulation is entirely dependent on the superior rectus vessels. In addition, in long-standing cases, the superior rectus muscle undergoes fibrosis often requiring a superior rectus recession. So usually a staged procedure is needed. Nishida et al.^[4] have described a no-split, no-tenotomy technique for the treatment of abducens palsy. We applied the same technique in this case to reduce risk of anterior segment ischemia as well as need for second procedure. Makino S et al.^[9] have previously described a case of inferior rectus aplasia managed by a no-split transposition of horizontal recti to the inferior rectus insertion site. As there is no tenotomy involved, the ciliary vessels are spared and hence this procedure can be safely combined with a superior rectus recession. Our report demonstrates that this procedure when combined with superior rectus recession is effective in correcting large angle hypertropias and improves the ocular motility as well as cosmesis. However, this needs validation with more cases and perhaps longer follow-up.

Conclusion

Ocular alignment, cosmesis and function improved in our patient without any significant adverse effects using Nishidas technique. This approach can be used effectively in cases of inferior rectus aplasia in lieu of tendon transposition.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

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