Congenital fibrosis of the extraocular muscles is a rare hereditary strabismus disorder manifesting as severe limitation of ductions invariably associated with ptosis. Treatment classically involves recessions of the tight muscles. We describe one such patient with severe limitation of up gaze and large chin-up posture due to tight inferior rectus muscles. After only partial response to bilateral large inferior rectus recessions, vertical transposition surgery was planned. Despite significant restriction of the inferior rectus muscles, bilateral horizontal rectus muscle transposition toward the superior rectus muscles successfully normalized the head posture and improved ptosis.
A 3-year-old boy presented to the Pediatric Ophthalmology Clinic at the American University of Beirut Medical Center with severe chin-up posture and bilateral ptosis since infancy. He was a product of full-term gestation and normal delivery. Medical history was negative and family history was negative for eye disorders.
On examination, he could fix and follow well with both eyes. He had a severe chin-up posture of 60° and absent upper eyelid creases (Figure 1). Palpebral fissures measured 5 mm in both eyes and Bell’s phenomenon could not be elicited.
Patient at presentation with severe chin-up posture.
External examination revealed a right upper eyelid chalazion. Slit-lamp examination showed signs of severe dryness in the inferior part of the cornea bilaterally, deep and quiet anterior chambers, normal pupils, and clear lenses. Motility examination revealed severe elevation deficiency (−5.0) in all upward gaze with normal horizontal ductions. He was orthotropic on Krimsky test with his chin-up posture. Dilated funduscopy showed +1 to +2 excyclotorsion in both eyes; otherwise the fundus examination was within normal limits. Magnetic resonance imaging of the brain and orbits revealed bilateral superior rectus muscle hypoplasia with normal brain structures (Figure 2).
Magnetic resonance imaging of orbits showing bilateral superior rectus muscle hypoplasia.
Surgery and forced duction testing were planned. Under general anesthesia, forced duction testing showed that both eyes could not be supraducted and could not reach the primary gaze position with bilateral inferior rectus restriction (−5.0). The working diagnosis was congenital fibrosis of the inferior rectus muscles. Large recessions of both inferior rectus muscles (13 mm from limbus, 5.5 mm from the original insertion) were performed. Postoperative examination showed decrease in the chin-up posture to 25°. The patient still had bilateral severe restriction in elevation in both eyes. After 5 months, further surgery was planned to treat the residual chin-up posture and elevation restriction. Forced duction testing under anesthesia again showed significant restriction (−3.0) of inferior rectus muscles and the eyes could barely reach midline (Figure 3).
Intraoperative forced duction testing after prior inferior rectus recessions showing persistent severe restriction to elevation.
The superior rectus muscle was noted to be mildly hypoplastic; hence superior rectus muscle resection was not our first choice. A full tendon width transposition was thought to provide the best treatment option in this case. Transposition of both horizontal rectus muscles toward the superior rectus muscle along the spiral of Tillaux was performed bilaterally with posterior augmentation sutures.
One month after the transposition, the patient had only mild chin-up posture (5°), almost resolved right upper eyelid ptosis, and mild residual left upper eyelid ptosis (Figure 4). Because this persisted in the follow-up period, he was referred for ptosis evaluation; bilateral frontalis sling suspension was performed. The decision to correct the ptosis was taken only after ensuring stability of eye alignment postoperatively because pseudoptosis is common in this setting. On the last follow-up visit 2 months after ptosis surgery, only minimal chin-up posture was noted with equal fixation; motility examination still showed the limited supraduction (−4.0) with orthotropia on Krimsky test.
Gradual improvement of chin-up posture from (A) 60° at presentation to (B) 25° after inferior rectus recessions to (C) 5° after transposition surgery and finally to (D) almost complete resolution after ptosis surgery.
The fibrosis syndromes of extraocular muscles are characterized by replacement of normal extraocular and levator muscle with fibrous tissue.1 Recent research has also indicated an etiologic role to cranial nerve maldevelopment, referred to now as the congenital cranial dysinnervation syndromes.2 The clinical presentation depends on the number of affected muscles and the degree of fibrosis. Ptosis with various degrees of severity is a common but not constant feature of the different clinical and genetic types.3 We believe our patient belongs to this group of disorders with ptosis and primary fibrosis of the inferior rectus muscles with secondary hypoplasia of the superior rectus muscles. Familial cases of the congenital fibrosis of extraocular muscles are inherited in either an autosomal dominant or an autosomal recessive manner, but it may also occur sporadically.4,5 Three clinical forms have been described. Patients with congenital fibrosis of extraocular muscles type 1 have bilateral ptosis and infraducted eyes and elevation restriction. Individuals with congenital fibrosis of extraocular muscles type 2 are born with bilateral ptosis and exotropia. In congenital fibrosis of extraocular muscles type 3, patients have a similar phenotype as congenital fibrosis of extraocular muscles type 1 but with variable expressivity and asymmetrical ocular involvement.6,7
The surgical approach in patients with congenital fibrosis of extraocular muscles depends on forced duction testing at the time of surgery and the motility assessment.8 Inferior rectus muscle recession and myectomy with additional recession of the conjunctiva are the most common procedures used for correcting hypotropia. Recession/resection procedures are performed in patients with bilateral horizontal strabismus.9
We present a different surgical approach in the context of congenital fibrosis of the inferior rectus muscle. Because our patient had bilateral superior rectus hypoplasia and did not demonstrate any improvement in elevation after large inferior rectus recessions, we decided to fully transpose the horizontal muscles toward the superior rectus muscle. The cause of the patient’s chin-up posture in this case could be attributed more to the hypoplasia of the superior rectus muscle.
The transposition procedure was first described in 1969 to treat patients with double elevator palsy and it resulted in significant improvement in hypotropia postoperatively.10 However, classic teaching dictates that if the antagonist muscle is tight, results of transposition surgery would be disappointing unless the latter muscle is weakened (surgical recession or botulinum toxin injection). In cases where concerns of anterior segment ischemia arise, partial transpositions have been advised (Hummelsheim procedure). Because our patient was young and healthy with a low risk of anterior segment ischemia, we decided to transpose the muscles totally to get the maximal effect. There is no previous report on the effect of transposition procedures in patients with hypotropia secondary to muscle fibrosis. Our patient had significant improvement in hypotropia and chin-up posture after augmented horizontal rectus muscle transposition despite tight inferior rectus muscles at the time of surgery. This is one surgical option for those difficult patients with severe limitation in ocular movements.
- Flaherty MP, Grattan-Smith P, Steinberg A, Jamieson R, Engle EC. Congenital fibrosis of the extraocular muscles associated with cortical dysplasia and maldevelopment of the basal ganglia. Ophthalmology. 2001;108:1313–1322. doi:10.1016/S0161-6420(01)00582-6 [CrossRef]
- Oystreck DT, Engle EC, Bosley TM. Recent progress in understanding congenital cranial dysinnervation disorders. J Neuroophthalmol. 2011;31:69–77. doi:10.1097/WNO.0b013e31820d0756 [CrossRef]
- Reck AC, Manners R, Hatchwell E. Phenotypic heterogeneity may occur in congenital fibrosis of the extraocular muscles. Br J Ophthalmol. 1998;82:676–679. doi:10.1136/bjo.82.6.676 [CrossRef]
- Von Noorden GK. Congenital herediatary ptosis with inferior rectus fibrosis. Arch Ophthalmol. 1970;83:378–80. doi:10.1001/archopht.1970.00990030378017 [CrossRef]
- Harley RD, Rodrigues MM, Crawford JS. Congenital fibrosis of the extraocular muscles. Am J Ophthalmol. 1978;76:197–226.
- Traboulsi EI, Lee BA, Mousawi A, Khamis AR, Engle EC. Evidence of genetic heterogeneity in autosomal recessive congenital fibrosis of the extraocular muscles. Am J Ophthalmol. 2000;129:658–662. doi:10.1016/S0002-9394(99)00467-5 [CrossRef]
- Mackey DA, Chan WM, Chan C, et al. Congenital fibrosis of the vertically acting extraocular muscles maps to the FEOM3 locus. Hum Genet. 2002;110:510–512. doi:10.1007/s00439-002-0707-5 [CrossRef]
- Yazdani A, Traboulsi EI. Classification and surgical management of patients with familial and sporadic forms of congenital fibrosis of the extraocular muscles. Ophthalmology. 2004;111:1035–1042. doi:10.1016/j.ophtha.2003.08.030 [CrossRef]
- Hiatt RL, Halle AA. General fibrosis syndrome. Ann Ophthalmol. 1983;15:1103–1109.
- Knapp P. The surgical treatment of double-elevator paralysis. Trans Am Ophthalmol Soc. 1969;67:304–323.