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Abnormal Insertion of the Inferior Oblique Muscle Is Rare

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Abnormal Insertion of the Inferior Oblique Muscle Is Rare Dohvoma VA, et al., J Ophthalmic Clin Res 2019, 6: 061 DOI: 10.24966/OCR-8887/100061 HSOA Journal of Ophthalmology & Clinical Research Case Report There was no under-action or over-¬action of any muscle, includ- Abnormal Insertion of the ing the inferior oblique. The right eye was the fixating eye. Under general anesthesia, the position of the fixating eye was unchanged, Inferior Oblique Muscle: A while the non-fixating eye showed less divergence. Unilateral re- cess-resect procedure on the no-fixating eye was our carried out. A 7 Report of 2 Cases mm medial rectus resection was done through a limbal incision. The lateral rectus muscle was also approached by a limbal incision. After Dohvoma VA1,2*, Ebana Mvogo SR1, Mvilongo TC2, Chilla F2 dissection, a thick fleshy tendon was hooked (Figure 2). Full-thick- 1,2 and Ebana Mvogo C ness bites were passed at the edges to secure the muscle. The muscle 1Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, was cut close to the insertion. An anomalous insertion of the inferior Cameroon oblique muscle was noticed along an oblique line (upward and back- 2Yaoundé Central Hospital, Yaoundé, Cameroon ward), just beneath the lateral rectus muscle with partial fusion to the inferior border of the lateral muscle tendon. No other belly was found upon careful examination of the inferior temporal quadrant. The infe- rior oblique muscle was secured and cut, to allow for the lateral rectus Abstract to be recessed. A 10mm recession of the lateral rectus was done. The Abnormal insertion of the inferior oblique muscle is rare. The au- inferior oblique muscle was sutured to the sclera 10 mm behind the thors report 2 cases observed during surgery for primary comitant lower border of the lateral rectus muscle tendon. Post operatively, the exotropia. The patients presented no associated vertical deviation patient was orthotropic (Figure 3). nor head tilt preoperatively. There was no under action or overaction of any muscle including the inferior oblique on motility testing. The inferior oblique muscle was repositioned to its normal anatomic posi- tion. Great care should be taken during lateral rectus muscle surgery to identify the inferior oblique muscle. Introduction Congenital abnormal insertions of extraocular muscles are not uncommon. They might be isolated or associated to craniofacial syn- dromes [1]. There are a few reports of isolated abnormal insertions of the horizontal recti muscle [2-4]. Isolated abnormal insertions of the oblique muscles are uncommon. We report 2 cases of abnormal Figure 1: Large angle exotropia. insertions of the inferior oblique muscle. Case 1 A 9-year old boy presented with a large angle comitant exotro- pia which was noticed in the first year of life. Vision was 20/20 in each eye. Anterior segment examination and fundus were normal in each eye. There was a 45 Prism Diopter (PD) exotropia (Figure 1). *Corresponding author: Dohvoma VA, Department of Ophthalmology and ENT; Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, Camer- oon, E-mail: [email protected] Citation: Dohvoma VA, Ebana Mvogo SR, Mvilongo TC, Chilla F, Ebana Mvo- go C (2019) Abnormal Insertion of the Inferior Oblique Muscle: A Report of 2 Cases. J Ophthalmic Clin Res 6: 061. Received: November 28, 2019; Accepted: December 06, 2019; Published: December 13, 2019 Figure 2: a) hook engaging thick fleshy tendon of the lateral rectus muscle; Copyright: © 2019 Dohvoma VA, et al. This is an open-access article distributed b) forceps holding lateral muscle tendon. Tendon (arrow) and some fibers under the terms of the Creative Commons Attribution License, which permits un- (star) of the inferior oblique muscle. restricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Citation: Dohvoma VA, Ebana Mvogo SR, Mvilongo TC, Chilla F, Ebana Mvogo C (2019) Abnormal Insertion of the Inferior Oblique Muscle: A Report of 2 Cases. J Ophthalmic Clin Res 6: 061. • Page 2 of 3 • In the case reported by Prakash et al., a fleshy mass was a part of the inferior oblique muscle, with its insertion 5 mm above the upper border of the lateral rectus. The anterior edge of the insertion was 10 mm behind the insertion of the lateral rectus muscle. In our cases, the full length of the inferior oblique muscle tendon was beneath the lateral rectus muscle, such that recession of the lateral rectus muscle along its trajectory was not possible. This is the reason why we disin- serted the inferior oblique muscle and sutured it at its normal anatom- ic site. Figure 3: Orthotropia following surgery. The insertion of the inferior oblique is normally situated beneath the inferior border of the lateral rectus muscle, the anterior most edge being 2.2 mm underneath the lateral rectus muscle and 9 to 10mm Case 2 behind the insertion of lateral rectus muscle. In the cases we report, it was directly beneath the lateral rectus muscle tendon. A 30-year old male patient presented with large angle comitant ex- otropia since birth. Corrected vision was 20/20 in each eye. Ductions Conclusion and versions were normal. The angle of deviation was 50 PD. There was mild reduction in the deviation under general anesthesia, with Anomalous insertion of the inferior oblique muscle makes it is both eyes in abduction. In the left eye, the medial rectus was resected prone to injury while operating on the lateral rectus muscle. Strabis- by 9 mm and the lateral rectus was recessed by 11 mm. The lateral mus surgeons should pay attention to inspect muscles per operatively. rectus of the right eye was approached through a limbal incision. Af- Patient Consent ter dissecting, hooking and securing the muscle, it was cut close to its insertion. An anomalous insertion of the inferior oblique muscle The authors certify that they have obtained consent from the adult was seen behind the tendon of the lateral rectus (Figure 4). No other patient and from the parent of the child to publish this manuscript. belly was found upon careful examination of the inferior temporal They understand that efforts will be made to conceal their identity. quadrant. The inferior oblique muscle was secured and cut, to allow for the lateral rectus to be recessed. An 11mm recession of the lateral Conflict of Interest rectus was done. The inferior oblique muscle was sutured to the sclera The authors report no conflict of interest. 10 mm behind the lower border of the lateral rectus muscle tendon. Post operatively, there was 6PDof residual exotropia, with no vertical References deviation. 1. Wine SB, Saad N, Vella ME (2000) Bilateral inferior insertion of lateral rectus muscles associated with schizencephaly. Clin Exp Ophthalmol 28: 69-70. 2. Rosenbaum AL, Jampolsky A (1975) Pseudoparalysis caused by anoma- lous insertion of superior rectus muscle. Arch Ophthalmol 93: 535-537. 3. Okano M, Matsuo T, Konishi H, Hasebe S, Tadokoro Y, et al (1990) Anom- alous posterior insertion of medial rectus muscle simulating congenital oc- ulomotor palsy. Jpn J Ophthalmol 34: 275-279. 4. Choi H, Kim H, Jeon H (2016) Abnormal medial rectus insertion present- ing exotropia: a case report and review of the literature. Int J Ophthalmo Figure 4: Forceps holding lateral rectus tendon and hook engaging inferior l9: 1852-1854. oblique muscle. 5. Park SW, Kim HG, Heo H, Park YG (2009) Anomalous Scleral Insertion of Superior Oblique in Axenfeld-Rieger Syndrome. Korean J Ophthalmol Discussion 23: 62-64. 6. Prakash P, Nayak BK, Menon V (1983) Abnormal insertion of inferior Abnormal insertions of extraocular muscles are mostly reported oblique. Indian J Ophthalmol 31: 21-22. by surgeons who observe these during surgery. For horizontal rec- ti muscles, they may either mimic a palsy or a comitant strabismus [3,4]. For oblique muscles, a suspicion of an abnormal insertion could be made during clinical examination, as the case of severe superior oblique overaction in relation to an abnormal insertion of the superior oblique muscle [5]. Others might present no under-action or over-ac- tion as the case of an abnormal insertion of the inferior oblique mus- cle reported by Prakash et al in which the patient presented no associ- ated `A’ or `V’ pheno¬menon, no under action or over¬action of any muscle, including the inferior oblique [6]. Volume 6 • Issue 3 • 100061 J Ophthalmic Clin Res ISSN: 2378-8887, Open Access Journal DOI: 10.24966/OCR-8887/100061 Journal of Anesthesia & Clinical Care Journal of Genetics & Genomic Sciences Journal of Addiction & Addictive Disorders Journal of Hematology, Blood Transfusion & Disorders Advances in Microbiology Research Journal of Human Endocrinology Advances in Industrial Biotechnology Journal of Hospice & Palliative Medical Care Journal of Agronomy & Agricultural Science Journal of Internal Medicine & Primary Healthcare Journal of AIDS Clinical Research & STDs Journal of Infectious & Non Infectious Diseases Journal of Alcoholism, Drug Abuse & Substance Dependence Journal of Light & Laser: Current Trends Journal of Allergy Disorders & Therapy Journal of Modern Chemical Sciences Journal of Alternative, Complementary & Integrative Medicine Journal of Medicine: Study & Research Journal of Nanotechnology: Nanomedicine & Nanobiotechnology Journal of Alzheimer’s & Neurodegenerative Diseases Journal of Neonatology & Clinical Pediatrics Journal of Angiology & Vascular Surgery Journal of Nephrology & Renal Therapy Journal of Animal Research & Veterinary Science Journal of Non Invasive Vascular Investigation Archives of Zoological
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