Supplementary Material for: Temporal Bone Meningoencephalocele Associated with Cholesteatoma: Systematic Literature Review and a Case Series

Background: Temporal bone meningoencephalocele (TB-MEC) diagnosed with or following cholesteatoma is a rare yet complex neurotological scenario. This study aims to characterize the clinical features and treatment strategies to facilitate clinicians’ decision-making and patients’ counseling.
Methods: We conducted a retrospective case series with a systematic literature review of the past 3 decades. For the literature review, PRISMA guidelines were followed, with articles sourced from PubMed and EMBASE. The study examined demographics, clinical aspects, imaging findings, surgical approaches, and postoperative outcomes.
Results: We identified 75 cases (n=72 from the literature and n=3 original). The majority of the patients with TB-MEC had prior cholesteatoma surgeries (79%), mostly canal wall down (CWD) mastoidectomy, with a relatively high complication rate (15%) at presentation. TB-MECs were incidentally discovered intraoperatively in 39.5% of the cases. Most (65%) of the preoperatively diagnosed had major defects (>1cm). Tegmen mastoidum was involved in 68%. Surgical treatment employed trans-mastoid approach in 72%, including minor and major defects, whereas middle fossa or combined approaches were reserved for major defects only. Autologous grafts, mainly temporalis fascia, were the primary choice for reconstruction (98%), regardless of defect sizes or surgical approach. Single surgery was mostly sufficient, irrespective of defect size (100% and 93% for minor and major defects), and complications were minimal.
Conclusions: Despite advancements in imaging, TB-MED are still discovered intraoperatively at a substantial rate. High-risk cases are patients with prior complications and multiple past surgeries, mainly CWD. Although previously described complications were ominous, today, a single-stage procedure yields positive outcomes.

背景：伴发或继发于胆脂瘤（cholesteatoma）的颞骨脑膜脑膨出（Temporal bone meningoencephalocele, TB-MEC）是一种罕见却复杂的耳神经科临床病症。本研究旨在明确其临床特征与治疗策略，以助力临床医师制定诊疗决策并为患者提供咨询。
方法：本研究开展了一项回顾性病例系列研究，并对近30年的相关文献进行了系统回顾。文献回顾严格遵循PRISMA指南，文献检索数据库为PubMed与EMBASE。本研究分析了患者人口学特征、临床特征、影像学表现、手术入路及术后结局。
结果：本研究共纳入75例病例（其中72例来自文献回顾，3例为本院原创病例）。79%的颞骨脑膜脑膨出患者既往有胆脂瘤手术史，其中以鼓室乳突根治术（canal wall down, CWD）为主，初诊时并发症发生率相对较高（15%）。39.5%的病例在术中意外发现颞骨脑膜脑膨出。术前确诊的病例中，65%存在直径大于1cm的大型颅骨缺损。68%的病例累及乳突盖（Tegmen mastoidum）。72%的患者采用经乳突入路进行手术治疗，该入路可适用于各类大小的颅骨缺损；而中颅窝入路或联合入路仅用于大型缺损的修复。自体移植物（主要为颞肌筋膜（temporalis fascia））是重建的首选材料（占比98%），不受缺损大小或手术入路的影响。无论缺损大小如何，单次手术大多可达到治疗效果（小型缺损患者的单次手术成功率为100%，大型缺损为93%），且术后并发症极少。
结论：尽管影像学技术已有长足进步，颞骨脑膜脑膨出仍有相当比例在术中才被发现。高危患者为既往出现并发症且接受过多次手术的人群，以有鼓室乳突根治术史者为主。尽管既往报道的并发症情况较为凶险，但如今采用单阶段手术即可获得良好的治疗效果。