Anatomical Classification and Clinical Significance of Right Middle Lobe Vein Confluence Variations in Right Upper Lobectomy: A Three-Dimensional Reconstruction Study

IF 2.5 4区医学 Q2 Medicine

Clinical and Experimental Pharmacology and Physiology Pub Date : 2025-07-21 DOI:10.1111/1440-1681.70058

Tian Hao, Lei Xu, Si-Ming Jiang, Min Zhang, Ming-jian Ge

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Abstract

Background

Anatomical variations of the right middle lobe (RML) veins pose significant risks during video-assisted thoracoscopic right upper lobectomy (RUL), where unrecognised veins traversing the horizontal fissure may be injured, compromising venous drainage. While 3D reconstruction aids surgical planning, a comprehensive classification system for RML venous confluences was lacking.

Methods

This retrospective cohort study analysed 2007 patients undergoing lung surgery (2017–2023) using preoperative CT-based 3D-CT bronchography and angiography (3D-CTBA; Mimics 21.0). Two thoracic surgeons independently classified RML veins (V⁴a, V⁴b, V⁵a, V⁵b) by drainage location: horizontal fissure (H-type), anterior mediastinal (A-type), or oblique fissure (O-type). Disagreements were resolved by a radiologist. Descriptive statistics characterised anatomical patterns.

Results

Analysis revealed complex venous drainage, with 31.83% (n = 639) demonstrating clinically critical H-type variations (confluencing into horizontal fissure). These were subclassified as HA (30.69%), HO (0.34%), and HAO (0.79%) patterns. V⁴a* traversed the fissure most frequently (29.07%), draining into upper lobe veins (V³b, V³a, V²c), while V⁴b* (2.86%) and V⁵a* (5.50%) exhibited lower traversal rates. No V⁵b* traversed the horizontal fissure. Rare drainage into the inferior pulmonary vein (IPV; V⁴a: 2.59%) or left atrium (0.20%) was observed, and the two-branch venous pattern predominated (42.87%). Previously unreported variants included downward-displaced RS³ (n = 10) and V⁶ → superior pulmonary vein drainage (n = 2). Intraoperative validation confirmed 3D-CTBA classification accuracy.

Conclusions

This large-scale study establishes the novel HAO classification system for RML venous anatomy, revealing a high prevalence (31.83%) of H-type variations that critically impact RUL safety. Preoperative 3D-CTBA using this framework enables tailored surgical strategies to preserve RML veins traversing the horizontal fissure, reducing injury risks and postoperative complications.

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右上肺叶切除术右中叶静脉汇流变化的解剖分型及临床意义：三维重建研究

背景：在电视胸腔镜下右上叶切除术（RUL）中，右中叶（RML）静脉的解剖变异会带来很大的风险，因为无法识别的穿过水平裂隙的静脉可能会受伤，从而影响静脉引流。虽然3D重建有助于手术计划，但缺乏RML静脉汇合的综合分类系统。方法回顾性队列研究分析了2007例肺手术患者（2017-2023）术前基于ct的3D-CT支气管造影和血管造影(3D-CTBA；模仿21.0)。两位胸外科医生独立将RML静脉（V4a、V4b、V5a、V5b）按引流位置分类：水平裂（h型）、前纵隔裂（a型）、斜裂（o型）。分歧由一位放射科医生解决。描述性统计描述了解剖模式。结果分析显示静脉引流复杂，其中31.83% （n = 639）表现出临床关键的h型变异（汇入水平裂隙）。这些亚型分为HA（30.69%）、HO（0.34%）和HAO（0.79%）。V4a*通过裂隙的频率最高（29.07%），流向上叶脉（V3b、V3a、V2c），而V4b*和V5a*通过裂隙的频率较低（2.86%）。没有V5b*穿过水平裂缝。少见的下肺静脉引流；V4a: 2.59%)或左心房（0.20%），以双支静脉型为主（42.87%）。以前未报道的变异包括RS3向下移位（n = 10）和V6→上肺静脉引流（n = 2）。术中验证证实了3D-CTBA分类的准确性。这项大规模研究建立了RML静脉解剖的新型HAO分类系统，揭示了h型变异的高患病率（31.83%），严重影响RUL的安全性。术前使用该框架的3D-CTBA可以定制手术策略，以保留穿过水平裂缝的RML静脉，降低损伤风险和术后并发症。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Clinical and Experimental Pharmacology and Physiology 医学-生理学

CiteScore

6.20

自引率

0.00%

发文量

128

审稿时长

6 months

期刊介绍： Clinical and Experimental Pharmacology and Physiology is an international journal founded in 1974 by Mike Rand, Austin Doyle, John Coghlan and Paul Korner. Our focus is new frontiers in physiology and pharmacology, emphasizing the translation of basic research to clinical practice. We publish original articles, invited reviews and our exciting, cutting-edge Frontiers-in-Research series’.