Research Article| Volume 65, ISSUE 7, P869-874, July 2012

Pediatric orbital floor trapdoor fractures: Outcomes and CT-based morphologic assessment of the inferior rectus muscle

  • Ryan M. Neinstein
    PGY-5, Division of Plastic and Reconstructive Surgery, Department of Surgery, University of Toronto, Ontario, Canada
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  • John H. Phillips
    Division of Plastic and Reconstructive Surgery, The Hospital for Sick Children, Ontario, Canada

    Department of Surgery, University of Toronto, Ontario, Canada
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  • Christopher R. Forrest
    Corresponding author. The Hospital for Sick Children, Suite 5430 – 555 University Avenue, Toronto, Ontario M5G 1X8, Canada. Tel.: +1 416 813 8659; fax: +1 416 813 6637.
    Division of Plastic and Reconstructive Surgery, The Hospital for Sick Children, Ontario, Canada

    Department of Surgery, University of Toronto, Ontario, Canada
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Published:March 29, 2012DOI:



      Trauma to the pediatric orbit may produce a unique fracture in which entrapment of the periorbital tissue and/or inferior rectus muscle may occur due to a “trap-door” effect of the compliant orbital floor. This study was designed to assess the outcome following the surgical management of orbital trapdoor fractures in children and to examine alterations in the morphology of the inferior rectus (IR) muscle.


      Outcome assessment on patients undergoing surgery at the Hospital For Sick Children, Toronto with symptomatic orbital floor trapdoor fractures over a 10-year period and a CT-based morphometric analysis of the inferior rectus muscle were performed.


      18 patients (5F, 13M) mean age 12.6 years (range 8.3–16.6 years) underwent surgical exploration (average time to surgery 9.7 ± 3.5 days (range 1–45 days). Follow-up was 15.4 months (range 6–36 months). All patients noted improvement in extra-ocular muscle (EOM) range of motion post-operatively: 7 patients had normal EOM with no diplopia; 9 patients had minimal diplopia on extreme secondary (upwards) gaze and 2 patients had residual significant diplopia with upward gaze. CT morphologic assessment (8 patients) demonstrated: a) zone of bony injury was posterior to the equator of the globe; b) minimal to no extra-conal fat exists to protect the IR muscle; c) a trend toward increased length in the injured IR muscle.


      With surgical intervention, improvement of diplopia (complete or near-complete resolution) occurred in 16/18 (89%) of patients presenting with symptomatic trapdoor orbital floor fractures. CT-based assessment demonstrated the vulnerability of the inferior rectus muscle with close proximity to the orbital floor and lack of periorbital fat for protection. Alteration of the length of the IR muscle may impact the force-length relationship and play a role in the outcomes. Early surgical intervention for symptomatic trapdoor fractures is recommended.


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        • Kwon J.H.
        • Moon J.H.
        • Kwon M.S.
        • Cho J.H.
        The differences of blowout fracture of the inferior orbital wall between children and adults.
        Arch Otolaryngol Head Neck Surg. 2005; 131: 723-727
        • Soll D.B.
        • Poley B.J.
        Trapdoor variety of blowout fracture of the orbital floor.
        Am J Ophthalmol. 1965; 60: 269-272
        • Posnick J.C.
        • Wells M.
        • Pron G.E.
        Pediatric facial fractures: evolving patterns of treatment.
        J Oral Maxillofac Surg. 1993; 51 (discussion 44–5): 836-844
        • Jordan D.R.
        • Allen L.H.
        • White J.
        • Harvey J.
        • Pashby R.
        • Esmaeli B.
        Intervention within days for some orbital floor fractures: the white-eyed blowout.
        Ophthal Plast Reconstr Surg. 1998; 14: 379-390
        • de Man K.
        • Wijngaarde R.
        • Hes J.
        • de Jong P.T.
        Influence of age on the management of blow-out fractures of the orbital floor.
        Int J Oral Maxillofac Surg. 1991; 20: 330-336
        • Koornneef L.
        New insights in the human orbital connective tissue. Result of a new anatomical approach.
        Arch Ophthalmol. 1977; 95: 1269-1273
        • Levinson S.R.
        • Canalis R.F.
        Experimental repair of orbital floor fractures.
        Arch Otolaryngol. 1977; 103: 188-191
        • Smith B.
        • Lisman R.D.
        • Simonton J.
        • Della Rocca R.
        Volkmann’s contracture of the extraocular muscles following blowout fracture.
        Plast Reconstr Surg. 1984; 74: 200-216
        • Smith B.
        • Regan Jr., W.F.
        Blow-out fracture of the orbit; mechanism and correction of internal orbital fracture.
        Am J Ophthalmol. 1957; 44: 733-739
        • Brismar J.
        Orbital phlebography. II. Anatomy of superior ophthalmic vein and its tributaries.
        Acta Radiol. 1974; 15: 481-496
        • Matic D.B.
        • Tse R.
        • Banerjee A.
        • Moore C.C.
        Rounding of the inferior rectus muscle as a predictor of enophthalmos in orbital floor fractures.
        J Craniofac Surg. 2007; 18: 127-132
        • Herzog W.
        • Joumaa V.
        • Leonard T.R.
        The force-length relationship of mechanically isolated sarcomeres.
        Adv Exp Med Biol. 2010; 682: 141-161
        • Jamal B.T.
        • Pfahler S.M.
        • Lane K.A.
        • et al.
        Ophthalmic injuries in patients with zygomaticomaxillary complex fractures requiring surgical repair.
        J Oral Maxillofac Surg. 2009; 67: 986-989
        • Weiland J.D.
        • Humayun M.S.
        • Dagnelie G.
        • de Juan Jr., E.
        • Greenberg R.J.
        • Iliff N.T.
        Understanding the origin of visual percepts elicited by electrical stimulation of the human retina.
        Graefes Arch Clin Exp Ophthalmol. 1999; 237: 1007-1013
        • Manson P.N.
        • Clifford C.M.
        • Su C.T.
        • Iliff N.T.
        • Morgan R.
        Mechanisms of global support and posttraumatic enophthalmos: I. The anatomy of the ligament sling and its relation to intramuscular cone orbital fat.
        Plast Reconstr Surg. 1986; 77: 193-202
        • Martinez A.J.
        • Hay S.
        • McNeer K.W.
        Extraocular muscles: light microscopy and ultrastructural features.
        Acta Neuropathol. 1976; 34: 237-253
        • Tompsett D.H.
        Anatomical techniques.
        E & S Livingston, London1970
        • Putterman A.M.
        • Stevens T.
        • Urist M.J.
        Nonsurgical management of blow-out fractures of the orbital floor.
        Am J Ophthalmol. 1974; 77: 232-239
        • Lynch G.S.
        • Frueh B.R.
        • Williams D.A.
        Contractile properties of single skinned fibres from the extraocular muscles, the levator and superior rectus, of the rabbit.
        J Physiol (Lond). 1994; 475: 337-346
        • Quaia C.
        • Ying H.S.
        • Optican L.M.
        The viscoelastic properties of passive eye muscle in primates. III: force elicited by natural elongations.
        PLoS One. 2010;8; 5: e9595
        • Asmussen G.
        • Beckers-Bleukx G.
        • Marechal G.
        The force-velocity relation of the rabbit inferior oblique muscle; influence of temperature.
        Pflugers Arch. 1994; 426: 542-547
        • Gordon A.M.
        • Huxley A.F.
        • Julian F.J.
        The variation in isometric tension with sarcomere length in vertebrate muscle fibres.
        J Physiol. 1966; 184: 170-192