Short Reports Inferior oblique anterior transposition for the unilateral hypertropia associated with bilateral inferior rectus muscle aplasia Faeeqah Almahmoudi, MD,a,b and Arif O. Khan, MDb Bilateral inferior rectus muscle aplasia in the absence of craniofacial abnormality is a rare but possibly under-recognized form of strabismus. Unilateral hypertropia in primary position seems to be a recurrent feature of this condition. We report a case of a 20-year-old woman with left hypertropia in primary position who was found on computed tomography to have bilateral inferior rectus muscle aplasia. A unilateral inferior oblique anterior transposition resulted in correction of the vertical deviation in primary position.
Case Report
A
20-year-old woman presented at the King Khaled Eye Specialist Hospital, Riyadh, with a chief complaint of her left eye being higher than her right eye. At 3 years of age she had undergone uncomplicated bilateral medal rectus recessions with half-tendon width supraplacement for what had been diagnosed as A-pattern esotropia with superior oblique overaction. Thereafter a left hypertropia was noted but no further surgical procedures were performed. On examination, visual acuity was 20/25 in the right eye and 20/30 in the left eye with spectacle correction of 2.00 1 3.00 082 (right) and 1.50 1 3.00 015 (left). There was no abnormal head position. Torsional and upbeat nystagmus could be appreciated. There was no relative afferent pupillary defect. Bilateral inferior scleral show was noted. Alternate cover testing revealed an esotropia of 15D and a left hypertropia of 15D at distance fixation (Figure 1A). In lateral gaze (both versions and ductions) there was an ipsilateral large hypertropia, with 5 depression during abduction (Video 1, available at jaapos. org). Fundus examination revealed bilateral incyclotorsion. Inferior rectus muscle aplasia was suspected and confirmed by computed tomography (Figure 1B). To address patient’s primary position hypertropia the left inferior oblique muscle was transposed anteriorly to a
Author affiliations: aKing Fahd Armed Forces Hospital, Jeddah, Saudi Arabia; bKing Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia Submitted January 26, 2014. Revision accepted February 14, 2014. Correspondence: Arif O. Khan, MD, Division of Pediatric Ophthalmology, King Khaled Eye Specialist Hospital, Riyadh 11462, Saudi Arabia (email: [email protected]). J AAPOS 2014;-:1-2. Copyright Ó 2014 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/$36.00 http://dx.doi.org/10.1016/j.jaapos.2014.02.005
Journal of AAPOS
FIG 1. A, Left hypertropia in primary position can be appreciated by corneal light reflexes in a preoperative clinical photograph; bilateral inferior scleral show is also apparent. B, A coronal computed tomographic slice (posterior to the globe) confirms absence of the inferior rectus muscle bilaterally (no extraocular muscle tissue inferior to the central optic nerve); C, Postoperative correction of the former left hypertropia in primary position can be appreciated by corneal light reflexes.
point approximately where the temporal border of the inferior rectus should have been, that is, 6 mm posterior to the limbus. One week postoperatively there was no vertical deviation in primary position and an esotropia of 15D (Figure 1C). Versions and ductions remained unchanged. Her postoperative ocular motility examination was stable at 6 months’ follow-up.
Discussion Nonsyndromic inferior rectus muscle aplasia is rare, particularly bilateral cases.1,2 For unilateral cases, ipsilateral moderate to large primary position hypertropia is expected. In our patient as well as other bilateral cases described in the literature moderate unilateral hypertropia was seen in primary position.2-5
1
2
Volume - Number - / - 2014
Almahmoudi and Khan
Table 1. Previous cases of confirmed bilateral inferior rectus aplasia without frank craniofacial abnormality Case 1 2 3 4 5
Source 3
Imai et al Lin and Yen4 Astle et al2 Astle et al2 Pimenides et al5
Ethnicity
Sex
Horizontala
Verticala
Evidence
Surgery
Japanese Asian Iranian Vietnamese South American/Asian
F F M F F
None 45 XT 6 XT 4 XT 4 XT
R HT 16 LHT 14 LHT Not noted 7 LHT
CT CT OR OR OR
Transposition LSR rc Transposition Transposition LSR rc, RLR rc
CT, computed tomography; HT, hypertropia; L, left; LR, lateral rectus muscle; OR, operating room; R, right; Rc, recession; SR, superior rectus muscle; XT, exotropia; transposition: inferior transposition of horizontal muscles. a Primary position deviation.
There are at least 5 documented patients in the literature with bilateral inferior rectus muscle aplasia in the absence of frank craniofacial abnormality and confirmed by imaging and/or surgical exploration—a Japanese woman,3 an Asian woman,4 an Iranian man,2 a Vietnamese woman,2 and a woman of South American and Asian descent.5 Primary position unilateral hypertropia was documented in 4 of these 5 patients (Table 1). Additional clinical features suggested bilateral inferior rectus weakness or aplasia before imaging or surgical exploration. These included A-pattern strabismus, large ipsilateral hypertropia during abduction, and an inability to depress during abduction, which, in the context of the A pattern, could conceivably be misinterpreted as superior oblique overaction in the contralateral adducted eye, particularly in young or uncooperative children—this is apparently what happened with our patient when she was a child. It is unclear why bilateral inferior rectus aplasia would be repeatedly associated with a unilateral hypertropia. It may be related to anomalous insertions of other extraocular muscles on the globe or other orbital connective tissue abnormalities, as was noted in some cases of inferior rectus muscle aplasia.2,4,6 In the present case, no abnormalities of the left inferior oblique muscle were noted, and no further orbital exploration was attempted. Our patient’s inferior scleral show may have been related to the lack of the normal connection between the lower lid retractions and the inferior rectus muscle. This has not been previously described as a sign of inferior rectus muscle aplasia, although published photographs of at least 2 other cases indicate a similar finding.4,5 Elevator weakening and, more recently, horizontal muscle inferior transposition are the most commonly reported surgical techniques for lowering the hypertropic eye in patients with inferior rectus muscle aplasia, with varying results.2 With such procedures there is a concern for anterior segment ischemia in older and/or vascularly compromised patients, especially since one rectus muscle is congenitally absent. Thus operating on the inferior oblique muscle, which does not carry ciliary vessels to the anterior segment, is appealing. Anterior transposition of
the inferior oblique muscle changes its function from an elevator to an inferior anchor of the globe because its neurovascular bundle becomes taut rather than lax.7 This procedure has been used to treat unilateral hypertropia in the context of dissociated vertical deviation, inferior oblique muscle overaction, and unilateral torn or aplastic inferior rectus muscle.8-10 We report its utility for the treatment of primary position hypertropia associated with bilateral inferior rectus aplasia.
Acknowledgments The authors thank Abdullah Khan, medical student at King Saud University in Riyadh, Saudi Arabia, for his help with references for this manuscript. References 1. Diamond GR, Katowitz JA, Whitaker LA, Quinn GE, Schaffer DB. Variations in extraocular muscle number and structure in craniofacial dysostosis. Am J Ophthalmol 1980;90:416-18. 2. Astle WF, Hill VE, Ells AL, Chi NT, Martinovic E. Congenital absence of the inferior rectus muscle—diagnosis and management. J AAPOS 2003;7:339-44. 3. Imai S, Sonoda H, Sakai T. A case of congenital absence of both inferior rectus muscles [in Japanese]. Jpn J Clin Ophthalmol 1983; 37:1443-6. 4. Lin PY, Yen MY. Congenital absence of bilateral inferior rectus muscles: a case report. J Pediatr Ophthalmol Strabismus 1997;34:382-4. 5. Pimenides D, Young S, Minty I, Spratt J, Tiffin PA. Familial aplasia of the inferior rectus muscles. J Pediatr Ophthalmol Strabismus 2005;42: 222-7. 6. Ozkan SB, Ozsunar Dayanir Y, Gokce Balci Y. Hypoplastic inferior rectus muscle in association with accessory extraocular muscle and globe retraction. J AAPOS 2007;11:488-90. 7. Stager DR, Weakley DR Jr, Stager D. Anterior transposition of the inferior oblique. Anatomic assessment of the neurovascular bundle. Arch Ophthalmol 1992;110:360-62. 8. Seawright AA, Gole GA. Results of anterior transposition of the inferior oblique. Aust N Z J Ophthalmol 1996;24:339-45. 9. Gamio S, Tartara A, Zelter M. Recession and anterior transposition of the inferior oblique muscle [RATIO] to treat three cases of absent inferior rectus muscle. Binocul Vis Strabismus Q 2002; 17:287-95. 10. Parvataneni M, Olitsky SE. Unilateral anterior transposition and resection of the inferior oblique muscle for the treatment of hypertropia. J Pediatr Ophthalmol Strabismus 2005;42:163-5.
Journal of AAPOS
Case Report
A
20-year-old woman presented at the King Khaled Eye Specialist Hospital, Riyadh, with a chief complaint of her left eye being higher than her right eye. At 3 years of age she had undergone uncomplicated bilateral medal rectus recessions with half-tendon width supraplacement for what had been diagnosed as A-pattern esotropia with superior oblique overaction. Thereafter a left hypertropia was noted but no further surgical procedures were performed. On examination, visual acuity was 20/25 in the right eye and 20/30 in the left eye with spectacle correction of 2.00 1 3.00 082 (right) and 1.50 1 3.00 015 (left). There was no abnormal head position. Torsional and upbeat nystagmus could be appreciated. There was no relative afferent pupillary defect. Bilateral inferior scleral show was noted. Alternate cover testing revealed an esotropia of 15D and a left hypertropia of 15D at distance fixation (Figure 1A). In lateral gaze (both versions and ductions) there was an ipsilateral large hypertropia, with 5 depression during abduction (Video 1, available at jaapos. org). Fundus examination revealed bilateral incyclotorsion. Inferior rectus muscle aplasia was suspected and confirmed by computed tomography (Figure 1B). To address patient’s primary position hypertropia the left inferior oblique muscle was transposed anteriorly to a
Author affiliations: aKing Fahd Armed Forces Hospital, Jeddah, Saudi Arabia; bKing Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia Submitted January 26, 2014. Revision accepted February 14, 2014. Correspondence: Arif O. Khan, MD, Division of Pediatric Ophthalmology, King Khaled Eye Specialist Hospital, Riyadh 11462, Saudi Arabia (email: [email protected]). J AAPOS 2014;-:1-2. Copyright Ó 2014 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/$36.00 http://dx.doi.org/10.1016/j.jaapos.2014.02.005
Journal of AAPOS
FIG 1. A, Left hypertropia in primary position can be appreciated by corneal light reflexes in a preoperative clinical photograph; bilateral inferior scleral show is also apparent. B, A coronal computed tomographic slice (posterior to the globe) confirms absence of the inferior rectus muscle bilaterally (no extraocular muscle tissue inferior to the central optic nerve); C, Postoperative correction of the former left hypertropia in primary position can be appreciated by corneal light reflexes.
point approximately where the temporal border of the inferior rectus should have been, that is, 6 mm posterior to the limbus. One week postoperatively there was no vertical deviation in primary position and an esotropia of 15D (Figure 1C). Versions and ductions remained unchanged. Her postoperative ocular motility examination was stable at 6 months’ follow-up.
Discussion Nonsyndromic inferior rectus muscle aplasia is rare, particularly bilateral cases.1,2 For unilateral cases, ipsilateral moderate to large primary position hypertropia is expected. In our patient as well as other bilateral cases described in the literature moderate unilateral hypertropia was seen in primary position.2-5
1
2
Volume - Number - / - 2014
Almahmoudi and Khan
Table 1. Previous cases of confirmed bilateral inferior rectus aplasia without frank craniofacial abnormality Case 1 2 3 4 5
Source 3
Imai et al Lin and Yen4 Astle et al2 Astle et al2 Pimenides et al5
Ethnicity
Sex
Horizontala
Verticala
Evidence
Surgery
Japanese Asian Iranian Vietnamese South American/Asian
F F M F F
None 45 XT 6 XT 4 XT 4 XT
R HT 16 LHT 14 LHT Not noted 7 LHT
CT CT OR OR OR
Transposition LSR rc Transposition Transposition LSR rc, RLR rc
CT, computed tomography; HT, hypertropia; L, left; LR, lateral rectus muscle; OR, operating room; R, right; Rc, recession; SR, superior rectus muscle; XT, exotropia; transposition: inferior transposition of horizontal muscles. a Primary position deviation.
There are at least 5 documented patients in the literature with bilateral inferior rectus muscle aplasia in the absence of frank craniofacial abnormality and confirmed by imaging and/or surgical exploration—a Japanese woman,3 an Asian woman,4 an Iranian man,2 a Vietnamese woman,2 and a woman of South American and Asian descent.5 Primary position unilateral hypertropia was documented in 4 of these 5 patients (Table 1). Additional clinical features suggested bilateral inferior rectus weakness or aplasia before imaging or surgical exploration. These included A-pattern strabismus, large ipsilateral hypertropia during abduction, and an inability to depress during abduction, which, in the context of the A pattern, could conceivably be misinterpreted as superior oblique overaction in the contralateral adducted eye, particularly in young or uncooperative children—this is apparently what happened with our patient when she was a child. It is unclear why bilateral inferior rectus aplasia would be repeatedly associated with a unilateral hypertropia. It may be related to anomalous insertions of other extraocular muscles on the globe or other orbital connective tissue abnormalities, as was noted in some cases of inferior rectus muscle aplasia.2,4,6 In the present case, no abnormalities of the left inferior oblique muscle were noted, and no further orbital exploration was attempted. Our patient’s inferior scleral show may have been related to the lack of the normal connection between the lower lid retractions and the inferior rectus muscle. This has not been previously described as a sign of inferior rectus muscle aplasia, although published photographs of at least 2 other cases indicate a similar finding.4,5 Elevator weakening and, more recently, horizontal muscle inferior transposition are the most commonly reported surgical techniques for lowering the hypertropic eye in patients with inferior rectus muscle aplasia, with varying results.2 With such procedures there is a concern for anterior segment ischemia in older and/or vascularly compromised patients, especially since one rectus muscle is congenitally absent. Thus operating on the inferior oblique muscle, which does not carry ciliary vessels to the anterior segment, is appealing. Anterior transposition of
the inferior oblique muscle changes its function from an elevator to an inferior anchor of the globe because its neurovascular bundle becomes taut rather than lax.7 This procedure has been used to treat unilateral hypertropia in the context of dissociated vertical deviation, inferior oblique muscle overaction, and unilateral torn or aplastic inferior rectus muscle.8-10 We report its utility for the treatment of primary position hypertropia associated with bilateral inferior rectus aplasia.
Acknowledgments The authors thank Abdullah Khan, medical student at King Saud University in Riyadh, Saudi Arabia, for his help with references for this manuscript. References 1. Diamond GR, Katowitz JA, Whitaker LA, Quinn GE, Schaffer DB. Variations in extraocular muscle number and structure in craniofacial dysostosis. Am J Ophthalmol 1980;90:416-18. 2. Astle WF, Hill VE, Ells AL, Chi NT, Martinovic E. Congenital absence of the inferior rectus muscle—diagnosis and management. J AAPOS 2003;7:339-44. 3. Imai S, Sonoda H, Sakai T. A case of congenital absence of both inferior rectus muscles [in Japanese]. Jpn J Clin Ophthalmol 1983; 37:1443-6. 4. Lin PY, Yen MY. Congenital absence of bilateral inferior rectus muscles: a case report. J Pediatr Ophthalmol Strabismus 1997;34:382-4. 5. Pimenides D, Young S, Minty I, Spratt J, Tiffin PA. Familial aplasia of the inferior rectus muscles. J Pediatr Ophthalmol Strabismus 2005;42: 222-7. 6. Ozkan SB, Ozsunar Dayanir Y, Gokce Balci Y. Hypoplastic inferior rectus muscle in association with accessory extraocular muscle and globe retraction. J AAPOS 2007;11:488-90. 7. Stager DR, Weakley DR Jr, Stager D. Anterior transposition of the inferior oblique. Anatomic assessment of the neurovascular bundle. Arch Ophthalmol 1992;110:360-62. 8. Seawright AA, Gole GA. Results of anterior transposition of the inferior oblique. Aust N Z J Ophthalmol 1996;24:339-45. 9. Gamio S, Tartara A, Zelter M. Recession and anterior transposition of the inferior oblique muscle [RATIO] to treat three cases of absent inferior rectus muscle. Binocul Vis Strabismus Q 2002; 17:287-95. 10. Parvataneni M, Olitsky SE. Unilateral anterior transposition and resection of the inferior oblique muscle for the treatment of hypertropia. J Pediatr Ophthalmol Strabismus 2005;42:163-5.
Journal of AAPOS
