作者通过内镜经鼻入路对海绵窦外侧室（LCCS）进行了进一步深入研究，以提高外侧入路切除 Knosp 4 级垂体腺瘤（KG4PAs）的安全性和有效性。使用三具尸体标本进行内镜鼻内解剖，暴露LCCS以观察内部的神经血管和纤维结构。基于对 LCCS 的进一步了解，提出了侧向入路的子分类，并用于切除 86 个 KG4PA，并对这些病例的手术结果进行了回顾。 A型KG4PA代表肿瘤主要分布在后上和上外侧间室，B型KG4PA代表肿瘤主要分布在前下间室，AB型KG4PA代表肿瘤延伸到各个间室，具有4A和4B型的特征。作者发现了多个纤维将颈内动脉（ICA）的水平段锚定到外展神经。纤维、交感神经和下外侧干在LCCS中形成分区状结构，称为外展神经-ICA复合体（AIC），并且LCCS可被AIC分为上外侧室和下外侧室。因此，外侧入路又分为外侧上入路（LS）和前下入路（AI）。 LS入路主要用于切除A型KG4PA，AI入路用于切除B型KG4PA，两者结合用于切除AB型KG4PA。总切除率、次全切除率和部分切除率分别为81.4%、12.8%和5.8%。术后短暂性脑神经麻痹、术后永久性脑神经麻痹、ICA损伤、脑脊液漏例数分别为6例（6.9%）、2例（2.3%）、1例（1.2%）、1例（1.2%）。这项研究揭示了 LCCS 被 AIC 分为上外侧室和下外侧室，避免了 LCCS 具有垂直连通的误解。因此，针对KG4PAs的切除，侧向入路又分为LS入路和AI入路，这使得KG4PAs的手术治疗具有较高的总切除率和可接受的安全性。

The authors performed a further in-depth study of the lateral compartment of the cavernous sinus (LCCS) by the endoscopic endonasal approach to improve the safety and efficacy of the lateral approach for the removal of Knosp grade 4 pituitary adenomas (KG4PAs).Twenty-three cadaveric specimens were used for endoscopic endonasal dissection, and the LCCS was exposed to observe the neurovascular and fibrous structures within. A subclassification of the lateral approach based on further knowledge of the LCCS was proposed and used to resect 86 KG4PAs, and the surgical outcomes of these cases were reviewed. Type A KG4PAs represent tumor that was mainly distributed in the posterosuperior and superolateral compartments, type B KG4PAs represent tumor that was mainly distributed in the anteroinferior compartments, and type AB KG4PAs represent tumor that extended into each compartment with characteristics of types 4A and 4B.The authors identified multiple fibers that anchored the horizontal segment of the internal carotid artery (ICA) to the abducens nerve. The fibers, the sympathetic nerve, and the inferior lateral trunk form a partition-like structure in the LCCS named the abducens nerve-ICA complex (AIC), and the LCCS can be divided into the superolateral and inferolateral compartments by the AIC. Accordingly, the lateral approach was subclassified into the lateral superior (LS) approach and the anterior inferior (AI) approach. The LS approach was mainly used to resect type A KG4PAs, whereas the AI approach was used to resect type B KG4PAs, and a combination of the two was used to resect type AB KG4PAs. The gross-total, subtotal, and partial resection rates were 81.4%, 12.8%, and 5.8%, respectively. The numbers of cases of postoperative transient cranial nerve palsy, postoperative permanent cranial nerve palsy, ICA injury, and CSF leakage were 6 (6.9%), 2 (2.3%), 1 (1.2%), and 1 (1.2%), respectively.This study revealed that the LCCS is divided by the AIC into the superolateral and inferolateral compartments, avoiding the misconception that the LCCS has vertical communication. Therefore, the lateral approach was subclassified into the LS approach and the AI approach for the resection of KG4PAs, which allowed a high gross-total resection rate with acceptable safety in the surgical treatment of KG4PAs.