OBJECTIVE In the authors' microsurgical experience, the trans-middle cerebellar peduncle (MCP) approach to the lateral and central pons has been the most common approach to brainstem cavernous malformations (BSCMs). This approach through a well-tolerated safe entry zone (SEZ) allows a wide vertical or posterior trajectory, reaching pontine lesions extending into the midbrain, medulla, and pontine tegmentum. Better understanding of the relationships among lesion location, surgical trajectory, and long-term clinical outcomes could determine areas of safe passage. METHODS A single-surgeon cohort study of all primary trans-MCP BSCM resections was conducted from July 1, 2017, to June 30, 2021. Preoperative and postoperative MR images were independently reviewed by 3 investigators blinded to the intervention, using a standardized rubric to define BSCM regions of interest (ROIs) involved with a lesion or microsurgical tract. Statistical testing, including the chi-square test with the Bonferroni correction, logistic regression, and structural equation modeling, was performed to analyze relationships between ROIs and clinical outcomes. RESULTS Thirty-one patients underwent primary trans-MCP BSCM resection during the study period. The median age was 50 years (IQR 24-49 years); 19 (61%) patients were female, and 12 (39%) were male. Seven (23%) patients had familial cavernous malformation syndromes. The median follow-up was 9 months (range 6-37 months). At the last follow-up, composite neurological outcomes were favorable: 22 (71%) patients had 0 (n = 12, 39%) or 1 (n = 10, 32%) major persistent deficit, 5 patients (16%) had 2 deficits, 2 (7%) had 3 deficits, and 1 patient each (3%) had 4 or 6 deficits. Unfavorable composite outcomes were significantly associated with lesions (OR 7.14, p = 0.04) or surgical tracts (OR 12.18, p < 0.001) extending from the superior cerebellar peduncle (SCP) into the contralateral medial midbrain. The ipsilateral dorsal pons was the most frequently implicated ROI involving a surgical tract and the development of new postoperative deficits. This region involved the rhomboid pontine territory and transgression of the pontine tegmentum (OR 7.53, p < 0.001). Structural equation modeling supported medial midbrain and pontine tegmentum transgression as the primary drivers of morbidity. CONCLUSIONS Trans-MCP resection is a safe and effective treatment for BSCMs, including lesions with marked superior or inferior ipsilateral extension. Two trajectories are associated with increased neurological risk: first, a superomedial trajectory to lesions extending into the midbrain that transgresses the SCP, its decussation, or both; and second, a posteromedial trajectory to lesions extending into the pontine tegmentum. The corticospinal tract, SCP, and pontine tegmentum form an invisible triangle within the pontine white matter tolerant of transgression. When the surgeon works within this triangle, most deep pontine BSCMs, including large lesions, those with contralateral or posterior extension, and others extending into the midbrain and medulla, can be resected safely with the trans-MCP approach.

中文翻译：

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扩大经小脑中脚入路的范围：脑桥海绵状血管瘤、超出安全进入区的组织侵犯和隐形三角。

目的 根据作者的显微外科经验，经小脑中脚 (MCP) 入路治疗脑桥外侧和中央是治疗脑干海绵状血管瘤 (BSCM) 的最常见方法。这种通过耐受性良好的安全进入区 (SEZ) 的方法允许较宽的垂直或后轨迹，到达延伸至中脑、延髓和脑桥被盖的脑桥病变。更好地了解病变位置、手术轨迹和长期临床结果之间的关系可以确定安全通道的区域。方法 从 2017 年 7 月 1 日到 2021 年 6 月 30 日，对所有原发性跨 MCP BSCM 切除术进行了一项单外科医生队列研究。术前和术后 MR 图像由 3 名对干预措施不知情的研究人员独立审查，使用标准化的评分标准定义涉及病变或显微外科手术道的 BSCM 感兴趣区域 (ROI)。进行统计测试，包括使用 Bonferroni 校正的卡方检验、逻辑回归和结构方程模型，以分析 ROI 和临床结果之间的关系。结果 在研究期间，31 名患者接受了初次跨 MCP BSCM 切除术。中位年龄为 50 岁（IQR 24-49 岁）；19 名患者（61%）为女性，12 名患者（39%）为男性。七名 (23%) 患者患有家族性海绵状血管瘤综合征。中位随访时间为 9 个月（范围 6-37 个月）。在最后一次随访中，综合神经学结果良好：22 名患者 (71%) 有 0 名患者 (n = 12, 39%) 或 1 名患者 (n = 10, 32%) 存在严重持续性缺陷，5 名患者 (16%) 有2 名患者有 2 项缺陷，2 名患者（7%）有 3 项缺陷，各 1 名患者（3%）有 4 或 6 项缺陷。不利的复合结果与从小脑上脚 (SCP) 延伸至对侧内侧中脑的病变 (OR 7.14，p = 0.04) 或手术道 (OR 12.18，p < 0.001) 显着相关。同侧背侧脑桥是最常涉及的 ROI，涉及手术道和新的术后缺陷的发展。该区域涉及菱形脑桥区域和脑桥被盖的侵入（OR 7.53，p < 0.001）。结构方程模型支持内侧中脑和桥脑被盖侵犯是发病的主要驱动因素。结论 Trans-MCP 切除术是治疗 BSCM 的一种安全有效的治疗方法，包括具有明显同侧上或下延伸的病变。有两种轨迹与增加的神经风险相关：首先，病变延伸至中脑的超内侧轨迹超出了 SCP、其交叉或两者；其次，病变的后内侧轨迹延伸至脑桥被盖。皮质脊髓束、SCP 和脑桥被盖在脑桥白质内形成一个看不见的三角形，可以容忍侵犯。当外科医生在这个三角形内工作时，大多数脑桥深部 BSCM，