目的　探讨改良扩大前颅底入路的显微解剖和临床应用效果。  方法　选用福尔马林固定的成人尸头标本15例，颅骨标本20例进行解剖学观察，并对13例应用该入路切除的颅底中线区肿瘤进行临床分析。  结果　与标准前颅底入路相比改良扩大前颅底入路的暴露范围明显扩大。通过将鼻骨与眶板一起截除，可保留足够长度的鼻中隔粘膜。术式的暴露范围主要受限于双侧的视神经、颈内动脉、翼管、舌下神经管等结构。本组13例中，9例全切除；1例近全切除；3例大部切除。术后发生并发症5例。无手术死亡。  结论　改良扩大前颅底入路具有暴露充分、脑损伤小、可有效保护嗅觉等优点。该入路是切除颅底中线部位侵犯眶、鼻、筛、蝶和斜坡肿瘤的较佳入路。

Objective　To explore microsurgical anatomy and clinical effects of the improved extended transbasal approach with preservation of olfaction.　Methods　The anatomic features were observed and measured in 20 dry skulls and 15 wet cadaveric heads. From March 2005 to June 2010, thirteen patients with tumors in midline of skull base were surgically treated through the extended transbasal approach with the preservation of olfaction function.　Results　The extended transbasal approach provided a significant increased operating field compared to that of the standard transbasal approach. Nasal mucosa attached to the cribriform plate could be remained by removing the nasal bone and orbital plate during the osteotomy. The optic nerves，carotid arteries，vidian canals，hypoglossal canals and other structures would be the perturbation for the further extension of operating field. 9 among 13 patients were totally removed the tumors. Five patients occurred postoperative complications. No surgical mortality occurred.　Conclusions　The main apparent advantages of the improved approach are the quality of surgical exposure, a low risk of brain damage, and the effective preservation of olfaction, which is an optimal selection for resecting the tumors in the midline part of skull base involving the orbit, paranasal sinus, ethmoid sinus, sphenoid sinus and clivus regions.