Friedland David R, Michel Michelle A
Division of Otology and Neuro-otologic Skull Base Surgery, Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
Otol Neurotol. 2006 Apr;27(3):346-54. doi: 10.1097/00129492-200604000-00010.
To use morphometric analyses of cranial thickness to investigate 2 cases of unanticipated calvarial bone resorption in superior canal dehiscence (SCD) resurfacing surgery.
Retrospective morphometric analysis of high-resolution computed tomography (CT) temporal bone scans in normal and control subjects with accompanying case reports.
Tertiary care referral center.
Two patients with SCD and failed resurfacing because of bone resorption. Temporal bone CT scans from 30 sex-matched controls.
Resurfacing of SCD via a middle fossa approach using a split thickness calvarial graft from the craniotomy site.
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.
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.
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.
运用颅骨厚度的形态学分析方法，对2例上半规管裂（SCD）修复手术中意外出现的颅骨骨质吸收病例展开研究。
对正常及对照受试者的颞骨高分辨率计算机断层扫描（CT）进行回顾性形态学分析，并附上病例报告。
三级医疗转诊中心。
2例因骨质吸收导致SCD修复失败的患者。30名性别匹配的对照受试者的颞骨CT扫描结果。
通过中颅窝入路，使用开颅部位的分层颅骨移植片对SCD进行修复。
中颅窝开颅骨瓣的平均横截面积，以及中颅窝底上方30度和45度处的平均颅骨厚度。
2例患者出现SCD修复手术延迟失败，表现为症状复发。两者的高分辨率CT扫描结果，以及其中1例的术中确认结果，均证实了骨移植片的吸收。高分辨率CT扫描对上半规管裂患者中颅窝开颅横截面积的测量结果显示，与正常对照组相比，这2例患者的值显著降低（曼-惠特尼U检验，p<0.05）。颞鳞骨外的颅骨厚度有所降低，但未达到统计学意义。
颅骨的形态学测量结果表明，与对照组相比，SCD患者的颞鳞骨更薄。因此，导致颅盖骨缺损的过程超出了岩骨尖。这表明可能存在颞外因素导致裂孔的形成。这些发现对该疾病的手术治疗也具有启示意义。由于骨移植片质量降低且可能易于吸收，修复方法的失败率可能更高。与修复相比，封堵半规管的方法可能为解决迷路裂提供更确切的手段。
