Faculty Collaboration Database

Cranial thickness in superior canal dehiscence syndrome: implications for canal resurfacing surgery. Otol Neurotol 2006 Apr;27(3):346-54

Date

04/28/2006

Pubmed ID

16639273

DOI

10.1097/00129492-200604000-00010

Scopus ID

2-s2.0-33646841022 (requires institutional sign-in at Scopus site)   54 Citations

Abstract

OBJECTIVE: To use morphometric analyses of cranial thickness to investigate 2 cases of unanticipated calvarial bone resorption in superior canal dehiscence (SCD) resurfacing surgery.

DESIGN: Retrospective morphometric analysis of high-resolution computed tomography (CT) temporal bone scans in normal and control subjects with accompanying case reports.

SETTING: Tertiary care referral center.

PATIENTS: Two patients with SCD and failed resurfacing because of bone resorption. Temporal bone CT scans from 30 sex-matched controls.

INTERVENTION: Resurfacing of SCD via a middle fossa approach using a split thickness calvarial graft from the craniotomy site.

MAIN OUTCOME MEASURE: Mean cross-sectional area of the middle fossa craniotomy bone flap and mean cranial thickness at 30 and 45 degrees above the middle fossa floor.

RESULTS: Two patients had delayed failure of SCD resurfacing surgery as manifested by return of symptoms. High-resolution CT scans in both, and intraoperative confirmation in one, confirmed resorption of the bone graft. Measurements of cross-sectional area of the middle fossa craniotomy on high-resolution CT scans demonstrated significantly reduced values in the two SCD patients as compared with normal controls (Mann-Whitney U test, p<0.05). Cranial thickness outside the squamous temporal bone was reduced but did not reach statistical significance.

CONCLUSION: Morphometric measurements of the calvarium have demonstrated that the squamous temporal bone is thinner in patients with SCD as compared with controls. Thus, the process leading to defects in the tegmen extends beyond the petrous pyramid. This suggests that there may be extratemporal factors leading to the development of a dehiscence. These findings also have implications for the surgical treatment of this disorder. Resurfacing methods may have a higher failure rate as the bone graft has reduced mass and maybe prone to resorption. Canal plugging methods may provide a more definitive means of addressing the dehiscent labyrinth than resurfacing.

Author List

Friedland DR, Michel MA

Author

Michelle A. Michel MD Adjunct Professor in the Radiology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Adult
Case-Control Studies
Endoscopy
Evoked Potentials, Auditory
Humans
Labyrinth Diseases
Male
Otologic Surgical Procedures
Parietal Bone
Regression Analysis
Retrospective Studies
Semicircular Canals
Syndrome
Temporal Bone
Tomography, X-Ray Computed