Plontke Stefan K, Zimmermann Rainer, Zenner Hans-Peter, Löwenheim Hubert
Department of Otorhinolaryngology, Head and Neck Surgery and Tübingen Hearing Research Center, University of Tübingen, Germany.
Otol Neurotol. 2006 Oct;27(7):912-7. doi: 10.1097/01.mao.0000235310.72442.4e.
Despite its invasiveness, the temporary implantation of a microcatheter into the middle ear cavity is an appropriately safe method for providing continuous drug delivery to the inner ear.
For the application of drugs to the inner ear, different delivery strategies are available ranging from intratympanic injections to temporarily implanted microcatheters. It has recently been demonstrated that the choice of the drug delivery system influences the pharmacokinetics in the inner ear. If a continuous drug application over several weeks is required, a secure placement of the delivery device (i.e., the microcatheter) is necessary to guarantee efficient drug delivery and to avoid unwanted side effects.
Retrospective chart review.
During 2000 to 2005, 25 patients with acute unilateral severe-to-profound hearing loss or anacusis and failure of systemic high-dose glucocorticoid and rheological therapy were offered an intratympanic delivery of glucocorticoids via a temporarily implanted catheter and an external pump for up to 4 weeks as a salvage treatment option. The standardized surgical implantation and fixation technique developed for the microcatheter were characterized by six elements: 1) a medial and a lateral tunnel connected by a groove in the posterior wall of the bony ear canal, 2) stabilization of the catheter with bone wax and soft tissue plugs in the tunnels, 3) an ear canal packing, 4) a series of fixating sutures along the catheter, 5) an adhesive dressing, and 6) additional tapes at the connecting line between pump and catheter. At the end of the implantation period, the catheter was removed by a second surgical procedure allowing for evaluation of the catheter position and the condition of the middle ear space.
Adverse events included catheter dislocation, catheter obstruction, formation of mild granulation tissue in the middle ear cavity, tympanic membrane defects, and ear canal skin defects. With introduction of an improved implantation and fixation technique, the number of catheter dislocations could be significantly reduced. No complications were observed on long-term follow-up.
If the pharmacokinetics or pharmacodynamics of a specific local inner ear therapy approach requires a continuous intratympanic drug application (e.g., to restore hearing in patients with severe or profound hearing loss), the temporary implantation of a microcatheter by a standardized surgical technique is a feasible and appropriately safe method for providing continuous drug delivery to the inner ear.
尽管具有侵入性，但将微导管临时植入中耳腔是一种向内耳持续给药的适当安全方法。
对于内耳给药，有多种给药策略，从鼓室内注射到临时植入微导管。最近已证明，药物递送系统的选择会影响内耳的药代动力学。如果需要数周的持续药物应用，则需要安全放置递送装置（即微导管）以确保有效的药物递送并避免不良副作用。
回顾性病历审查。
在2000年至2005年期间，为25例急性单侧重度至极重度听力损失或全聋且全身大剂量糖皮质激素和流变学治疗无效的患者提供了通过临时植入导管和外部泵进行鼓室内糖皮质激素给药长达4周的挽救治疗方案。为微导管开发的标准化手术植入和固定技术具有六个要素：1）通过骨性耳道后壁的凹槽连接的内侧和外侧通道；2）用骨蜡和软组织塞在通道中稳定导管；3）耳道填塞；4）沿导管的一系列固定缝线；5）粘性敷料；6）泵与导管连接线处的额外胶带。在植入期结束时，通过第二次手术取出导管，以便评估导管位置和中耳腔状况。
不良事件包括导管移位、导管阻塞、中耳腔内轻度肉芽组织形成、鼓膜穿孔和耳道皮肤缺损。随着改进的植入和固定技术的引入，导管移位的数量可显著减少。长期随访未观察到并发症。
如果特定局部内耳治疗方法的药代动力学或药效学需要持续鼓室内给药（例如，恢复重度或极重度听力损失患者的听力），则通过标准化手术技术临时植入微导管是向内耳持续给药的可行且适当安全的方法。
