Ont Health Technol Assess Ser. 2020 Mar 6;20(4):1-85. eCollection 2020.
Neurofibromatosis 2 (NF2) is a rare genetic disorder that causes vestibular schwannomas to develop in both eighth cranial nerves. Almost all people with NF2 eventually become completely deaf as a result of progressive tumour enlargement or following surgical or radiotherapy treatment. Other rare abnormal conditions in the inner ears can also cause complete deafness. For people with either indication who are not candidates for cochlear implantation, auditory brainstem implantation is the only treatment option to restore some functional hearing. We conducted a health technology assessment of auditory brainstem implantation for adults with NF2 and severe inner ear abnormalities, which included an evaluation of effectiveness, safety, cost-effectiveness, the budget impact of publicly funding auditory brainstem implantation, and patient preferences and values.
We performed a systematic literature search of the clinical evidence. We assessed the risk of bias of each included study using the Risk of Bias in Non-randomized Studies-of Interventions (ROBINS-I) tool and the quality of the body of evidence according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group criteria. We performed a systematic economic literature search. We did not conduct a primary economic evaluation because the outcomes identified in our clinical evidence review were difficult to translate into measures appropriate for health economic modelling. We also analyzed the net budget impact of publicly funding auditory brainstem implantation over the next 5 years in Ontario, including the device, presurgical assessment, surgical procedure, and postsurgical rehabilitation. To contextualize the potential value of auditory brainstem implants, we spoke with six people with lived experience of NF2 and severe inner ear abnormalities.
We included 22 publications (16 in NF2, five in severe inner ear abnormalities, and one in complications of auditory brainstem implantation) in the clinical evidence review. In adults with NF2, auditory brainstem implantation when compared with no intervention allows any degree of improvement in sound recognition (GRADE: High), allows any degree of improvement in speech perception when used in conjunction with lip-reading (GRADE: High), and provides subjective benefits of hearing (GRADE: High). It likely allows any degree of improvement in speech perception when using the implant alone (GRADE: Moderate) and may improve quality of life (GRADE: Low). In adults with severe inner ear abnormalities, auditory brainstem implantation when compared with no intervention likely allows any degree of improvement in sound recognition (GRADE: Moderate) and in any speech perception when using the implant alone (GRADE: Moderate). It may allow any degree of improvement in speech perception when used in conjunction with lip-reading (GRADE: Low), provide subjective benefits of hearing (GRADE: Low), and improve quality of life (GRADE: Low).We did not identify any economic studies on auditory brainstem implantation for adults with NF2 or adults with deafness due to severe inner ear abnormalities. We estimated that the annual net budget impact of publicly funding auditory brainstem implantation in Ontario over the next 5 years would range from about $130,000 in year 1 for two procedures to about $260,000 in year 5 for four procedures.People with whom we spoke who had received an auditory brainstem implant reported that it restored some hearing ability and improved their quality of life, though they also reported ongoing challenges in using the device or side effects from the procedure.
When compared with no intervention, auditory brainstem implantation provides some benefit for completely deaf adults with NF2 or severe inner ear abnormalities who are not candidates for cochlear implantation. Based on evidence of moderate to high quality, auditory brainstem implants allow any degree of improvement in sound recognition and in speech perception when used in conjunction with lip-reading for people with NF2. The quality of evidence on these outcomes was low to moderate for people with severe inner ear abnormalities. These functional outcomes lead to subjective benefits of hearing which are consistently reported in the literature and in interviews with patients. We were unable to determine the cost-effectiveness of this treatment. We estimate that publicly funding auditory brainstem implantation in Ontario would result in additional costs of about $130,000 to $260,000 annually over the next 5 years.
神经纤维瘤病2型（NF2）是一种罕见的遗传性疾病，可导致双侧第八对脑神经出现前庭神经鞘瘤。几乎所有NF2患者最终都会因肿瘤逐渐增大或接受手术或放射治疗而完全失聪。内耳的其他罕见异常情况也可导致完全失聪。对于不适合进行人工耳蜗植入的上述任何一种情况的患者，听觉脑干植入是恢复一定功能性听力的唯一治疗选择。我们对NF2及严重内耳异常的成年患者的听觉脑干植入进行了卫生技术评估，包括对有效性、安全性、成本效益、公共资助听觉脑干植入的预算影响以及患者偏好和价值观的评估。
我们对临床证据进行了系统的文献检索。我们使用干预性非随机研究中的偏倚风险（ROBINS-I）工具评估每项纳入研究的偏倚风险，并根据推荐分级评估、制定和评价（GRADE）工作组标准评估证据体的质量。我们进行了系统的经济文献检索。我们未进行初步经济评估，因为我们临床证据综述中确定的结果难以转化为适合卫生经济建模的指标。我们还分析了安大略省未来5年公共资助听觉脑干植入的净预算影响，包括设备、术前评估、手术过程和术后康复。为了解听觉脑干植入的潜在价值，我们与6名有NF2及严重内耳异常实际经历的患者进行了交谈。
我们在临床证据综述中纳入了22篇出版物（16篇关于NF2，5篇关于严重内耳异常，1篇关于听觉脑干植入并发症）。在NF2成年患者中，与不进行干预相比，听觉脑干植入可使声音识别有任何程度的改善（证据等级：高），与唇读结合使用时可使言语感知有任何程度的改善（证据等级：高），并提供听力方面的主观益处（证据等级：高）。单独使用植入物时可能使言语感知有任何程度的改善（证据等级：中等），并可能改善生活质量（证据等级：低）。在严重内耳异常的成年患者中，与不进行干预相比，听觉脑干植入可能使声音识别有任何程度的改善（证据等级：中等），单独使用植入物时在任何言语感知方面也有改善（证据等级：中等）。与唇读结合使用时可能使言语感知有任何程度的改善（证据等级：低），提供听力方面的主观益处（证据等级：低），并改善生活质量（证据等级：低）。我们未找到关于NF2成年患者或因严重内耳异常导致失聪的成年患者听觉脑干植入的任何经济研究。我们估计，安大略省未来5年公共资助听觉脑干植入的年度净预算影响范围从第1年约130,000加元用于2例手术到第5年约260,000加元用于4例手术。我们与之交谈的接受了听觉脑干植入的患者报告称，该植入物恢复了一些听力能力并改善了他们的生活质量，不过他们也报告了在使用该设备方面持续存在的挑战或手术的副作用。
与不进行干预相比，听觉脑干植入为不适合进行人工耳蜗植入的完全失聪的NF2成年患者或严重内耳异常患者提供了一些益处。基于中高质量的证据，听觉脑干植入可使NF2患者在与唇读结合使用时声音识别和言语感知有任何程度的改善。对于严重内耳异常患者，这些结果的证据质量为低到中等。这些功能结果带来了听力方面的主观益处，这在文献和对患者的访谈中均有一致报道。我们无法确定这种治疗的成本效益。我们估计，安大略省公共资助听觉脑干植入在未来5年每年将导致约130,000至260,000加元的额外成本。
