鼓室内地塞米松注射相对于圆窗的最佳头部位置

文献信息

中文摘要

目的： 鼓室内地塞米松注射（ITDI）广泛用于内耳疾病。然而，通过圆窗膜（RWM）最大化药物吸收同时最小化咽鼓管（ET）冲刷的最佳头部位置仍未明确。本研究旨在采用多模式方法确定ITDI的理想头部位置，并将其与传统的45度头部旋转进行比较。
方法： 进行了结合尸体解剖、三维（3D）解剖建模和患者临床外淋巴采样的多模式分析。解剖了12具矢状切面的人颞骨尸体，以确定直接接触RWM所需的经耳道角度，并测量了相应的偏航、翻滚和俯仰头部位置角度。构建了外耳道、RWM和ET的3D打印解剖模型，以确认液体流向RW。使用额外的新鲜冷冻尸体比较了在传统或理想头部位置进行ITDI后的外淋巴地塞米松浓度。临床上，5例接受经迷路前庭神经鞘瘤切除术的患者在麻醉诱导和手术体位后接受ITDI，随后在手术期间进行外淋巴采样。
结果： 相对于RWM的最佳头部位置被确定为偏航58.9度、翻滚31.1度和俯仰22.5度。三维建模表明，当翻滚和俯仰一起优化时，药物流向RWM增加且ET冲刷减少，而单独偏航效果最小。尸体和临床患者外淋巴采样显示，理想头部位置的外淋巴地塞米松浓度始终高于传统45度位置。当尸体和临床样本合并进行探索性比较时，理想头部位置的地塞米松浓度比传统位置高2.94倍（0.0447% vs. 0.0152%），尽管这一差异未达到统计学显著性。
结论： 理想的鼓室内地塞米松递送需要除偏航外调整翻滚和俯仰。实施三轴理想头部位置是一种简单、经济有效的策略，可改善鼓室内类固醇吸收和治疗效果。

英文摘要

OBJECTIVE: Intratympanic dexamethasone injection (ITDI) is widely used for inner ear disorders. However, optimal head positioning to maximize drug absorption through the round window membrane (RWM) while minimizing Eustachian tube (ET) washout remains undefined. This study aimed to determine the ideal head position for ITDI using a multimodal approach and to compare it with the traditional 45-degree head rotation.
METHODS: A multimodal analysis incorporating cadaveric dissection, 3-dimensional (3D) anatomic modeling, and clinical perilymph sampling from patients was performed. Twelve sagittal-sectioned human temporal bone cadavers were dissected to identify the transcanal angle required for direct RWM contact, and corresponding yaw, roll, and pitch head-position angles were measured. A 3D-printed anatomic model of the external auditory canal, RWM, and ET was constructed to confirm fluid flow toward the RW. Additional fresh-frozen cadavers were used to compare perilymph dexamethasone concentrations following ITDI administered in either the traditional or ideal head position. Clinically, 5 patients undergoing translabyrinthine vestibular schwannoma resection received ITDI after induction of anesthesia and surgical positioning, followed by perilymph sampling during surgery.
RESULTS: The optimal head position relative to the RWM was identified as 58.9 degrees of yaw, 31.1 degrees of roll, and 22.5 degrees of pitch. Three-dimensional modeling demonstrated increased drug flow toward the RWM and reduced ET washout when roll and pitch were optimized together, while yaw alone had minimal effect. Cadaveric and clinical patient perilymph sampling showed a consistent trend toward higher perilymph dexamethasone concentrations in the ideal head position than in the traditional 45-degree position. When the cadaveric and clinical samples were pooled for exploratory comparison, the ideal head position showed a 2.94-fold higher dexamethasone concentration than the traditional position (0.0447% vs. 0.0152%), although this difference did not reach statistical significance.
CONCLUSION: Ideal intratympanic dexamethasone delivery requires adjustment of roll and pitch in addition to yaw. Implementing a 3-axis ideal head position is a simple, cost-effective strategy to improve intratympanic steroid absorption and therapeutic efficacy.