title: Inferior orbital septum release compared with lateral canthotomy and cantholysis in the management of orbital compartment syndrome.
abstract: OBJECTIVE
  The purpose of this study is to assess the utility of inferior orbital septum release compared with lateral canthotomy and inferior cantholysis for the treatment of orbital compartment syndrome.
  
  
  METHODS
  An experimental study design using a cadaver model for orbital compartment syndrome was used to compare the efficacy of inferior orbital septum release with lateral canthotomy and inferior cantholysis. Elevated orbital compartment pressures were created in a total of 10 orbits of 5 fresh cadaver heads. Compartment pressure and intraocular pressure were measured before and after inferior orbital septum release and lateral canthotomy/cantholysis. Additionally, orbital compartment pressure was compared with intraocular pressure at various pressures to assess correlation. Statistical analysis was performed on the collected data for efficacy comparison of the 2 procedures.
  
  
  RESULTS
  Both procedures were found significantly to reduce orbital compartment pressure. Lateral canthotomy and cantholysis was found to lower the pressure by an average of 56 mm Hg as compared with inferior septal release, which resulted in an average of 52-mm Hg reduction. Performing lateral canthotomy and cantholysis first, followed by inferior septal release, resulted in a total pressure reduction of 73 mm Hg, whereas reversing the order resulted in a reduction of 77 mm Hg. Both the first and second steps, regardless of the order of procedure, were found to result in a significant pressure reduction (p = 0.009 and 0.004, respectively). Comparison of a series of data points collected during the induction of the experimental compartment syndrome revealed a statistically significant correlation between orbital compartment pressure and intraocular pressure (Spearman correlation of 0.978 and p value <0.001).
  
  
  CONCLUSIONS
  The study demonstrates that both lateral canthotomy/cantholysis and inferior orbital septum release are equally effective at reducing orbital compartment pressure. Additionally, the data support an additive, synergistic reduction in compartment pressure when the procedures are performed consecutively. The correlation of orbital compartment pressure to intraocular pressure proves that intraocular pressure can be used as a reliable measurement of orbital pressure during acute changes in orbital mass. The results of this study demonstrate that the use of inferior orbital septum release in conjunction with lateral canthotomy and cantholysis is superior to the gold standard of isolated lateral canthotomy and cantholysis. We hope that the implementation of orbital septum release will result in superior visual outcomes.
authors.affiliation: Vanderbilt University Medical Center, Nashville, USA. alanoester@hotmail.com
authors.forename: Alan E
authors.initials: AE
authors.lastname: Oester
authors.forename: Brian T
authors.initials: BT
authors.lastname: Fowler
authors.forename: James C
authors.initials: JC
authors.lastname: Fleming
mesh_terms: D002102:Cadaver; D003161:Compartment Syndromes / Q000503:physiopathology / Q000601:surgery*; D003238:Connective Tissue / Q000601:surgery*; D019299:Decompression, Surgical / Q000379:methods; D006801:Humans; D007429:Intraocular Pressure; D009916:Orbital Diseases / Q000503:physiopathology / Q000601:surgery*; D013710:Tendons / Q000601:surgery