Summary
Introduction
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.
Methodology
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.
Results
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.
Conclusions
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.
Keywords
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Article info
Publication history
Published online: March 29, 2012
Accepted:
February 2,
2012
Received:
November 1,
2011
Footnotes
☆This work has been presented at the IPRAS 2011 meeting in Vancouver, May 2011.
Identification
Copyright
© 2012 Published by Elsevier Inc.
