Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Cologne, Cologne, Germany.
Otol Neurotol. 2010 Jun;31(4):624-9. doi: 10.1097/MAO.0b013e3181d2f04e.
An ossicular chain defect represents a challenging situation for otosurgeons. Despite modern reconstruction techniques, unsatisfying postoperative hearing results regularly occur. These are commonly caused by prosthesis dislocation. Whereas the reasons for prosthesis dysfunction occurring months or years after implantation are related to independent chronic conditions, early events of dislocations are more related to the technical fixation of the prosthesis inside the middle ear cavity. Consequently, a safe coupling between prosthesis head and tympanic membrane is essential for a successful type III tympanoplasty. Our study evaluated the use of a new prosthesis design with the aim to reduce short-term postoperative prosthesis dislocation in mind.
Prospective experimental and clinical study.
A modified titanium total ossicular replacement prosthesis (TORP), whose head had spikes that extend into the cartilaginous neotympanic membrane, was designed and tested experimentally and then clinically. The lateral holding force of the new prosthesis head against lateral shift was measured and compared with common prosthesis heads without spikes. After proving this design experimentally, the prostheses were used intraoperatively in 35 tympanoplasty type III operations. Results were analyzed prospectively and compared with 35 retrospectively analyzed controls with conventional TORP prostheses.
The lateral holding forces for the spike prosthesis heads were significantly higher (134 mN) than those for common prosthesis heads (92 mN) at a contact pressure of 100 mN. Postoperatively, pure-tone audiometry revealed satisfying hearing results. Spiked and conventional titanium TORPs yielded postoperative air-bone gaps (ABGs) of 20.9 and 18.6 dB with 54% and 57% ABG closure, within 20 dB, respectively. The air-bone gap was reduced by an average of 14 and 15 dB, respectively. However, these differences were not statistically significant. Both in the study and in the control group, no signs of prosthesis dislocation were discovered.
The experimental data show that the new modified prosthesis head has an increased lateral holding force and thus reduces the risk of dislocation at the coupling side of the tympanic membrane. The postoperative hearing results are comparable to those of conventional prostheses. To confirm the advantage of the modified prosthesis plates over conventional prostheses, future studies with larger study populations are necessary.
听骨链缺损对耳科医生来说是一个具有挑战性的问题。尽管采用了现代重建技术，但术后听力结果仍不令人满意，这通常是由于假体移位引起的。而在植入数月或数年后出现假体功能障碍的原因与独立的慢性疾病有关，早期的脱位事件更多与假体在中耳腔内的技术固定有关。因此，假体头部与鼓膜之间的安全连接对于成功的 III 型鼓室成形术至关重要。我们的研究评估了一种新的假体设计的使用，旨在减少术后短期假体脱位。
前瞻性实验和临床研究。
设计并实验性测试了一种改良的钛全听骨置换假体（TORP），其头部有延伸到软骨性新鼓膜的刺，然后进行了临床测试。测量了新假体头部相对于侧向移位的侧向保持力，并与无刺的常见假体头部进行了比较。在实验中证明了这一设计后，在 35 例 III 型鼓室成形术中术中使用了这些假体。前瞻性分析结果，并与 35 例使用传统 TORP 假体的回顾性对照进行比较。
在接触压力为 100 mN 时，刺状假体头部的侧向保持力明显高于普通假体头部（134 mN）（92 mN）。术后纯音测听显示听力结果令人满意。带有刺的和常规的钛 TORP 的术后气骨导间隙（ABG）分别为 20.9dB 和 18.6dB，分别有 54%和 57%的 ABG 闭合在 20dB 以内。气骨导间隙分别平均减少了 14dB 和 15dB。然而，这些差异没有统计学意义。在研究组和对照组中，均未发现假体脱位的迹象。
实验数据表明，新型改良假体头部具有更大的侧向保持力，从而降低了鼓膜耦合侧脱位的风险。术后听力结果与常规假体相当。为了证实改良假体板相对于常规假体的优势，需要进行更大样本量的未来研究。
