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IH Ludwig; Pseudo Cranial Nerve Palsies due to Avulsion, or "Flap" Tears of the Extraocular Muscles . Invest. Ophthalmol. Vis. Sci. 2002;43(13):1482.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To report the new finding of avulsion-type injuries of the extraocular muscles which may masquerade as cranial nerve palsies. Methods: Fourteen patients were referred with clinical diagnoses of cranial nerve (CN) palsy, Four presented as third CN palsy, eight with fourth CN palsy, and two with sixth CN palsy. Six ascribed the onset of strabismus to episodes of blunt trauma. The others recalled trauma only after careful questioning. Trauma usually proceeded onset of diplopia by several weeks. None had orbital fractures. All underwent extraocular muscle surgery, with repair of injured muscles. Six required additional recession or resection of the involved, or other muscles, to achieve alignment. Results: Direct repair of the flap tear(s) alone, produced resolution of diplopia in eight patients. Clues to the presence of flap tear included restriction of motility on forced duction, but good muscle strength on force generation testing. A history of primarily facial trauma with little or no loss of consciousness suggested muscle injury rather than cranial nerve damage in these patients. Conclusion: Post-traumatic strabismus due to partial tears of the extraocular muscles was recently reported. (Ludwig and Brown, Transactions of the American Ophthalmological Society, 2001.) The mechanism is felt to be due to an avulsion of a portion of the extraocular muscle from the globe. As the disinserted "flap" of muscle scars into surrounding orbital connective tissue, strabismus develops. Cranial nerve palsy may be misdiagnosed in these patients. Early extraocular muscle repair can improve results and reduce patient morbidity.
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