Transnasal endoscopic management of petrous apex and clivus selected lesions

The objective of this study was to report a series of selected primary skull base benign lesions midline located by transnasal endoscopic transsphenoidal approach. A retrospective review of 5 cases is presented: four cholesterol granuloma of the petruos apex and one of the clivus. All patients have been successfully treated via transnasal endoscopic transsphenoidal approach. The mean duration of follow-up was 27 months (range 12–50 months). No postoperative complication such as CSF leak, meningitis, or encephalocele and no signs of recurrence have been noticed. The transnasal route is a minimally invasive, safe, and efficient technique to approach the petrous apex and clivus for selected midline skull base lesions removal.     

Anatomical landmarks for transnasal endoscopic skull base surgery

Resection of midline skull base lesions involve approaches needing extensive neurovascular manipulation. Transnasal endoscopic approach (TEA) is minimally invasive and ideal for certain selected lesions of the anterior skull base. A thorough knowledge of endonasal endoscopic anatomy is essential to be well versed with its surgical applications and this is possible only by dedicated cadaveric dissections. The goal in this study was to understand endoscopic anatomy of the orbital apex, petrous apex and the pterygopalatine fossa. Six cadaveric heads (3 injected and 3 non injected) and 12 sides, were dissected using a TEA outlining systematically, the steps of surgical dissection and the landmarks encountered. Dissection done by the “2 nostril, 4 hands” technique, allows better transnasal instrumentation with two surgeons working in unison with each other. The main surgical landmarks for the orbital apex are the carotid artery protuberance in the lateral sphenoid wall, optic nerve canal, lateral optico-carotid recess, optic strut and the V2 nerve. Orbital apex includes structures passing through the superior and inferior orbital fissure and the optic nerve canal. Vidian nerve canal and the V2 are important landmarks for the petrous apex. Identification of the sphenopalatine artery, V2 and foramen rotundum are important during dissection of the pterygopalatine fossa. In conclusion, the major potential advantage of TEA to the skull base is that it provides a direct anatomical route to the lesion without traversing any major neurovascular structures, as against the open transcranial approaches which involve more neurovascular manipulation and brain retraction. Obviously, these approaches require close cooperation and collaboration between otorhinolaryngologists and neurosurgeons.     

Combined endoscopic transmaxillary-transnasal approach to the pterygoid region, lateral sphenoid sinus, and retrobulbar orbit

OBJECTIVES: The sublabial transmaxillary approach to the pterygoid region was a popular one during the Caldwell-Luc, pre-endoscopic era. It was the procedure of choice for management of lesions of the pterygopalatine space, for internal maxillary artery ligation, and for vidian neurectomy. With the introduction of endoscopic instrumentation and techniques, the Caldwell-Luc procedure is rarely performed today. Also, because vidian neurectomy is performed less frequently, and because internal maxillary artery ligation for severe epistaxis has been replaced with transnasal endoscopic sphenopalatine artery ligation, the sublabial transmaxillary route is rarely used. We have found that combining the use of endoscopes via the sublabial approach and the transnasal endoscopic approach is very helpful for management of extreme lateral lesions of the sphenoid sinus, as well as the pterygoid region and the posterior orbit. METHODS: The records of patients who underwent a combined endoscopic transmaxillary-transnasal approach between 1994 and 2002 were reviewed. Indications for the procedure included extreme lateral sphenoid and pterygoid encephalocele (3 patients), pterygoid mucocele (2 patients), orbital apex lesion (2 patients), and pterygopalatine tumor (2 patients). RESULTS: Nine patients underwent the above-mentioned procedure. Wide and comfortable exposure of the involved region was achieved in all cases. Compared with the transnasal approach, the working distance, working comfort, and maneuverability of instruments were significantly enhanced. There were no major complications related to the approach. Because the maxillary wall opening is very small, infraorbital hypoesthesia is very limited and of short duration. CONCLUSIONS: Combining the transmaxillary and transnasal approaches for endoscopic management of pterygoid, lateral sphenoid, and retrobulbar orbit lesions provides excellent exposure and avoids the limited working angle and surgical struggle that may be associated with the use of the transnasal approach alone.     

经鼻内镜蝶窦进路岩尖胆脂瘤切除

目的 探讨经鼻内镜蝶窦进路岩尖部胆脂瘤囊内切除术的可行性及疗效.方法 回顾性分析2001-2006年经鼻内镜蝶窦进路切除鞍旁、岩尖部胆脂瘤患者3例的临床资料.3例患者均在全麻下经鼻内镜全筛窦、蝶窦开放,于蝶窦外侧壁、颈内动脉前方磨开颅底骨板进入岩尖部,切开并扩大胆脂瘤囊壁后,采用吸引、刮除和冲洗的方法将胆脂瘤进行囊内清除.结果 3例岩尖胆脂瘤经囊内切除手术,均一次清除干净,手术前伴有头痛和眶尖综合征的2例患者于术后当天即有症状改善,术后1～4周症状完全恢复,全部患者未发生手术并发症.术后随访3～7年,全部患者症状未再发,影像学检查胆脂瘤无复发.结论 靠近鞍旁区域的岩尖胆脂瘤可以采用经鼻内镜蝶窦进路行囊内切除手术,远期疗效可靠.     

经鼻内镜手术治疗颅底脊索瘤

脊索瘤是一种起源于胚胎发育时期残留脊索组织的先天性低恶性肿瘤，多发生于骶尾部及颅底中线部位，尤其是斜坡区域，其预后与肿瘤切除程度密切相关，肿瘤完全切除的患者多能长期生存。由于颅底脊索瘤多呈浸润性生长，侵袭范围广，累及颅底重要神经、血管及脑组织等，手术完全切除极其困难，因此被认为是神经外科治疗的难题之一。近年来随着神经内镜技术的发展，以及术中神经导航系统、电生理监测、经鼻超声系统和多普勒超声血管探测仪等监测技术的广泛应用，经鼻内镜入路能在直视下最大可能地安全切除颅底脊索瘤，并尽可能保留重要神经、血管功能，其手术创伤小，术后脑脊液漏等并发症发生率低，并且患者生存质量明显提高，已成为颅底脊索瘤手术治疗的首选方法。为进一步全面认识经鼻内镜治疗颅底脊索瘤的疗效及优缺点，我们查阅了近年来国内外公开发表关于经鼻内镜手术治疗颅底脊索瘤的相关文献，并从术前肿瘤评估分型、手术策略、肿瘤手术切除程度及其影响因素以及术后并发症等几方面对其进行综述。     

Transnasale Chirurgie der Orbita

The endonasal surgery has a branch in the transnasal orbital surgery. For this transnasal approach the anterior skull base, the medial and infero-medial orbita, the orbital apex with the optical nerve and the sphenoid sinus are within reach. In all primary and secondary malignant lesions with extension into the orbita, the transnasal biopsy is of importance for diagnosis, particularly in metastasis to the orbit and pseudo-tumors. Benign lesions like mucoceles and osteomas are accessible and fully removable. Good results have been obtained in endonasal orbital decompression and inhomogeneous space occupying intraorbital lesions like bleedings. Among the orbital traumatism, with restrictions fractures of the medial orbital wall, medial orbital floor and foreign bodies could be operated. The transnasal approach is not indicated in all diseases, which are situated mostly intraconally, supraorbitally and lateral of the bulbus as well as in tumors with intracranial extension. In summary, the transnasal orbital approach has its place as helpful addition to the transfacial and transcranial techniques and can even replace them in certain selected indications.     

影像导航引导鼻内镜下前颅底骨化纤维瘤切除术

目的 探讨影像导航系统在经鼻内镜切除前颅底骨化纤维瘤手术中的作用。方法 选择影像导航引导下经鼻内镜手术切除累积眶纸板、颅底骨质的筛窦骨化纤维瘤12例男性患者,初次手术9例,复发病例3例。术前行鼻窦CT连续扫描,骨算法,层厚1mm。结果 CT显示所有病例筛骨水平板、眶纸板受累。4例前界至额隐窝前缘（鼻骨后）;6例累及眶尖与蝶窦外侧壁交界处：1例广泛累及上颔骨、蝶骨大翼、蝶鞍和斜坡。11例彻底切除病灶,1例（病变广泛者）切除大部分肿瘤。平均手术时间3．2小时,影像导航配准过程平均25分钟。1例术中并发脑脊液漏,术中鼻内镜下修补成功;3例术中损伤眶纸板,无手术及术后并发症。术后随访5个月～4年,姑息手术病例肿瘤生长缓慢,其余病例无复发,症状明显改善。结论 借助影像导航引导,经鼻内镜手术切除累及眶纸板、前颅底骨质的骨化纤维瘤,具有一定优势,但病灶不应广泛侵及额隐窝、蝶骨及斜坡。     

经鼻内镜颅底缺损修补69例临床分析

目的总结经鼻内镜鼻颅底缺损修补的经验,评价鼻颅底缺损的病因、部位和经鼻内镜鼻颅底修补术的效果及关键技术。方法回顾性分析1998年1月至2006年6月69例鼻颅底缺损经鼻内镜颅底修补患者的临床资料,着重分析颅底缺损的病因、部位、手术效果及关键技术。结果随访6个月至11年,主要病因是外伤性颅底骨折（32例）、颅底或鼻-鼻窦占位性病变切除后（28例）和医源性颅底损伤（9例）;主要部位在筛窦,其次是蝶窦;一次手术成功率为91．3％（63／69）,最终成功率为95．7％（66／69）。结论经鼻内镜鼻颅底缺损修补术效果理想,缺损处彻底清创、制作缺损缘创面和修补物嵌塞于颅底内侧面是手术成功的关键,游离肌肉和筋膜是理想的修补材料。     

Endoscopic anatomy of the parasellar region

BACKGROUND: The aim of this study was to describe the endoscopic anatomy of the cavernous sinus and adjoining parasellar regions and their relationships to the sphenoid sinus. METHODS: An endoscopic transnasal transsphenoidal approach to the pituitary gland and posterior skull base was performed on three fresh frozen cadaver heads (six sides). Neural and vascular anatomic landmarks of the cavernous sinus and parasellar regions were identified and correlated with sphenoid surface anatomy. RESULTS: The posterior wall of the sphenoid sinus presents several surface landmarks allowing the identification of the sella, carotid artery, and optic nerve. Identification of the optic-carotid recess allows reflection of the internal carotid artery medially and access to the cavernous sinus. Further lateral dissection allows for easy identification of the oculomotor, trochlear, trigeminal, and abducens nerves. The ophthalmic artery then can be followed from its origin on the internal carotid artery coursing anteriorly into the orbit. The optic chiasm also can be easily identified superiorly. Posteriorly, careful dissection allows access to the basilar artery along the clivus. CONCLUSION: As endoscopic surgeons continue to expand their procedures to involve areas of the skull base outside the paranasal sinuses, knowledge of the endoscopic anatomy of the sella, parasellar, and adjacent areas is paramount. Critical landmarks are readily evident in the sphenoid sinus providing good access to neural and vascular structures of this region of the skull base.     

Endoscopic transsphenoidal biopsy of the sphenoid and clival mass

Abnormalities of the clivus/skull base occur most commonly as a result of disease spread from adjacent structures, but can also occur from primary involvement of the clivus. Traditionally, definitive diagnosis was made by CT guided biopsy or craniotomy. However, lesions can occur in this area that are not amenable to CT guided biopsy or craniotomy. Endoscopic transsphenoidal surgery can provide a safe method for obtaining a clival biopsy, debulking of tumor tissue, or definitive treatment without the morbidity and mortality of a craniotomy. This study was designed to describe our experience with the endoscopic approach to the skull base and clivus via the sphenoid sinus. A series of seven patients underwent endoscopic transsphenoidal biopsy of a sphenoid clival lesion. All patients avoided anticipated craniotomy, and definitive pathology was obtained in five of six patients. In two cases, excisional biopsy proved to be therapeutic. There were no deaths, and major complications included one CSF leak and one intraoperative hemorrhage, both of which were controlled immediately. The experience gained with these patients demonstrates the feasibility and safety of this new application of endoscopic sinus surgery for the diagnosis and possible treatment of lesions of the sphenoid and clivus.     

Endonasal endoscopic approach to the petrous apex: an image-guided quantitative anatomical study.

BACKGROUND: The petrous apex is a relatively inaccessible region, deeply situated within the skull base. Removal of lesions from this area, traditionally accomplished via lateral approaches, can cause significant morbidity. We undertook an anatomical study to investigate the surgical anatomy of the petrous apex through an endonasal endoscopic approach, which has been sporadically described in the literature, to investigate its feasibility and to characterise clear and consistent surgical landmarks for access. METHODS: Cadaveric dissections were performed on five heads. Pre-dissection computed tomography scans were used, with the BrainLab navigation system, to verify entry into the petrous apex. Surgical landmarks were characterised in relation to fixed sphenoid sinus structures, and surgical access before and after drilling the sphenoid sinus rostrum was quantitatively compared. RESULTS: The landmark for entry into the petrous apex was the intersection of a vertical line halfway between the medial surface of the internal carotid artery and the midline, with a horizontal line one-third of the way up from the postero-inferior floor of the sphenoid sinus. The dimensions of the postero-superior sphenoid sinus were characterised by the inter-carotid distance, pituitary-to-sphenoid-floor distance and the width of the sphenoid sinus floor, which were 15 +/- 3 mm, 16 +/- 3 mm and 26 +/- 1.6 mm respectively. The surface area of surgical access was 193 +/- 28 mm(2), increasing to 316 +/- 39 mm(2) after drilling of the sphenoid rostrum (P < 0.001; paired t-test). CONCLUSIONS: Endoscopic approach to the petrous apex is anatomically feasible, and, aided by image navigation, could extend the scope of endonasal surgery to access highly-selected lesions in the middle cranial fossa.     

电磁导航技术在鼻颅底手术中的应用

摘要：目的探讨电磁导航技术在鼻颅底手术中的临床应用。方法收集 2017 年 8月—2019 年 2月应用电磁导航技术行 15例鼻颅底手术,患者病变范围涉及蝶窦、鞍区、咽旁隙、颈静脉孔区、筛顶、蝶骨平台等解剖区域。术前均完善 CT、MRI 等影像学资料,录入导航系统行三维重建,鼻内镜下进行手术,涉及复杂、重要解剖结构时使用导航系统进行定位。结果15例手术中1例鼻颅底纤维血管瘤术中出血约1 000 ml,余手术出血均可控。15例手术术中均未出现重要结构损伤,术后无严重并发症。15 例患者术后随访3~20个月,1例鼻颅底腺样囊性癌患者术后12个月复查考虑肿瘤复发。结论电磁导航技术应用于鼻颅底手术中,安全、精准,手术并发症少,特别适用于解剖结果变异、修正鼻内镜手术、病变广泛的恶性肿瘤患者。     

鼻内镜下颅底占位性病变的微创手术

目的探讨经鼻内镜在颅底占位性病变手术中的应用。方法回顾性分析2000年6月至2006年9月42例颅底占位性病变患者的临床资料。其中前、中颅底恶性肿瘤13例，脊索瘤8例，侵袭性垂体瘤向蝶窦、蝶鞍颅底破坏者5例，蝶骨骨纤维异样增殖症4例，翼腭窝、颞下窝神经纤维瘤3例，纤维血管瘤3例，前、中颅底骨化纤维瘤3例，其他病变3例。结果42例患者中，肿瘤完全切除36例，病变次全切除6例，2例因出血过多分两次完成手术，其余病变均1次完全切除。术后1例患者右眼失明，1例患者出现脑脊液耳漏，保守治疗1周后痊愈。42例均进行随访，随访6—81个月，其中5例失访，8例复发，6例死亡，其余患者未见复发。结论内镜下颅底占位性病变外科手术治疗安全、有效、微创，但需根据一定的技术、设备条件，严格掌握手术适应证。     

以眶尖综合征为首发症状的鼻-眶-颅底侵袭性曲霉菌感染5例

目的:探讨以眶尖综合征为首发症状的免疫功能低下患者鼻-眶-颅底侵袭性曲霉菌感染的早期诊断、外科干预和全身抗真菌药物的应用。方法:回顾性分析5例以眶尖综合征为首发症状的鼻-眶-颅底侵袭性曲霉菌感染患者的临床资料、诊治经过、随访结果。结果:5例均以眶尖综合征为首发症状,无明显鼻-鼻窦症状,均首诊于神经内科。其中4例行内镜经鼻鼻窦-眶尖-颅底探查术,3例同时行视神经减压术。病理检查为侵袭性曲霉菌病变。1例术后即联合应用两性霉素B、伊曲康唑和卡泊净芬,术后第4天头疼明显缓解,术后3个月复查视力由术前1尺指数恢复至0.1,随访65个月症状得到控制。1例术后即开始应用两性霉素B,术后1个月头疼减轻,随访43个月视力无提高,病变无进行性发展。其余3例死亡,其中1例死于颅内真菌扩散,1例死于脑干出血,1例死于败血症。结论:眶尖综合征常是侵袭性鼻-眶-颅底曲霉菌病的早期临床表现。对免疫功能低下、以眶尖综合征为典型临床表现的患者应用类固醇激素治疗之前应考虑行内镜经鼻探查和活检,术中尽可能清除病变。早期诊断和外科干预有助于提高视力、缓解症状,该病预后差。     

经鼻内镜蝶鞍区手术蝶窦壁的应用解剖

目的研究蝶窦壁相关解剖结构的分区及空间定位，为经鼻内镜蝶鞍区手术提供立体解剖学依据。方法10具去脑颅底骨按九分区法划分蝶窦壁区域，测量蝶窦各壁之间相关的角度和距离参数；在1具新鲜完整尸头上模拟内镜下手术观察。结果视交叉平面-球形鞍底隆起角度为（121±8．52）°，海绵窦平面一鞍底平面角度为（129±9．35）°，斜坡凹陷平面-鞍底平面角度（124±7．54）°，颈内动脉视神经隐窝至鞍底移行处距离为（5．54±1．86）mm，至斜坡后缘的距离为（22．43±1．96）mm，至颈内动脉海绵窦段后曲部的距离为（15．86±2.13）mm；根据测量结果可建立起蝶窦壁九分区法的立体模型。结论蝶窦壁九分区法的立体模型，丰富了鼻内镜下蝶窦壁九分区法的内容，使其更加方便应用于手术。     

Long-term follow-up of juvenile nasopharyngeal angiofibromas: Analysis of recurrences

Objectives: Juvenile nasopharyngeal angiofibroma often recurs if the tumor is large. This report is a long-term follow-up of these cases. It establishes the prognostic values of tumor extensions, analyzes the anatomic factors involved in recurrences, describes the spontaneous evolution of remnants based on a radiographic follow-up, and evaluates the pertinence of complex combined surgical approaches for invasive tumors and the value of complementary endoscopy. Study Design: Retrospective review of 44 cases treated between 1985 and 1996. Methods: Statistical analysis of the correlation between recurrence and tumor extension as evaluated by systematic analysis of 18 putative tumor extensions on preoperative computed tomography scans. Results: Invasion of the skull base affected two-thirds of the patients, and the rate of recurrence was 27.5%. Extensions to the infratemporal fossa, sphenoid sinus, base of pterygoids and clivus, the cavernous sinus (medial), foramen lacerum, and anterior fossa were correlated with more frequent recurrence. Long-term radiographic follow-up revealed putative residual disease in nine asymptomatic patients: these remnants gradually involuted. Conclusions: The data in the current study emphasize the prognostic value of skull base invasion and the difficulty of complete resection of extended lesions. Tumor remnants detected in symptom-free patients should be kept under surveillance by repeated computed tomography scan, since involution may occur. Recurrent symptoms may be treated by radiotherapy (30 Gy) rather than by extended combined procedures. Endoscopic surgery should be combined with surgery for better control of skull base extensions.     

Endonasal endoscopic repair of cerebrospinal fluid leaks of the sphenoid sinus

BACKGROUND: Multiple reports have demonstrated the efficacy of the transnasal endoscopic repair of cerebrospinal fluid (CSF) leaks of the anterior cranial base. The literature, however, lacks a comprehensive clinical study specifically addressing the transnasal endoscopic repair of CSF leaks of the sphenoid sinus. OBJECTIVE: To ascertain the factors that significantly affect the surgical outcome after transnasal endoscopic repair of CSF leaks of the sphenoid sinus. METHODS: We retrospectively reviewed the medical records of all patients who underwent an endoscopic transnasal repair of CSF leaks of the sphenoid sinus at our teaching hospitals. RESULTS: Twenty-four patients with CSF leaks of the sphenoid sinuses that were repaired by the transnasal endoscopic approach were included in our study. Causes of the CSF leaks included trauma, surgery, neoplasms, and idiopathic causes. Obliteration was the most common technique used to repair the CSF fistulas (used in 15 [58%] of 26 procedures). Grafting materials included banked pericardium, mucosa, turbinate bone, and mucoperichondrium placed by underlay or onlay grafting or abdominal fat used to obliterate the sphenoid sinus. Twenty-two patients were successfully treated on the first attempt. A persistent leak in 2 patients with previously unrecognized high-pressure hydrocephalus was repaired during a second endoscopic surgery, quickly followed by ventriculoperitoneal shunting. CONCLUSIONS: Assuming an adequate repair, other factors such as the cause, the size of the defect, the technique and material used to repair the defect, and perioperative management do not affect the surgical outcome significantly. Untreated high-pressure hydrocephalus can lead to a recurrence or persistence of the leaks and should be suspected in patients with posttraumatic, idiopathic, or recurrent CSF leaks.     

Sphenoid sinus fungal balls

OBJECTIVES: We sought to examine the nature of fungal balls of the sphenoid sinus, in particular the exposure of adjacent skull base structures and the potential for surgical morbidity. METHODS: We retrospectively reviewed our series of 17 cases of sphenoid sinus fungal balls seen between 1998 and 2005 with reference to their diagnosis, radiologic changes, histopathology, and surgical management. RESULTS: Exposed structures included the pituitary fossa, cavernous sinus, and cavernous internal carotid artery, but this exposure did not result in an increase in perioperative complications. Sclerotic thickening of the sinus walls persisted, probably representing a chronic osteitis in response to concurrent bacterial infection. This appeared to be protective against further sinus wall erosions. Wall erosions did not heal. One patient demonstrated what appeared to be invasive fungal disease from a fungal ball. CONCLUSIONS: Sphenoid sinus fungal balls can occur with minimal symptoms in a mainly elderly population and require surgical removal. Sphenoid sinus fungal balls have a low rate of operative morbidity and should be effectively managed by transnasal endoscopic sphenoidotomy alone.     

内镜经鼻联合显微镜额眶颧颞入路处理颅内外沟通性肿瘤的临床分析

目的探讨内镜经鼻入路联合显微镜额眶颧颞入路在颅内外沟通性肿瘤手术中的应用。方法回顾分析2016年5月至2018年1月在天津市环湖医院采用内镜经鼻联合显微镜额眶颧颞入路进行手术治疗的7例颅内外沟通性肿瘤患者的临床资料。7例患者中男4例,女3例,年龄27~65岁,中位年龄48岁。7例患者中2例复发侵袭性垂体瘤,3例颅底脑膜瘤,1例斜坡软骨肉瘤,1例复发鼻咽癌。病变广泛累及鼻腔、鼻窦、双侧海绵窦、鞍区、鞍上、上斜坡、颞叶、翼腭窝、颞下窝以及颅内重要血管。7例患者均采用全身麻醉下内镜经鼻入路联合显微镜额眶颧颞入路肿瘤切除治疗,观察手术全切情况、术中术后并发症情况以及术后疗效。所有患者术后随访6~12个月,采用格拉斯哥预后分级(Glasgow outcome scale,GOS)评估患者预后。结果 7例患者中肿瘤全切5例,大部切除2例。术中未出现并发症。术后发生严重并发症2例:其中1例脑脊液鼻漏并颅内感染,经腰大池引流和鞘内注射药物治疗后治愈;1例动眼神经麻痹,随访期间内未恢复。术后其他并发症包括滑车神经功能障碍1例次,耳鸣1例次,面部麻木2例次,随访中部分神经功能恢复。术中术后无死亡病例。7例患者术后随访均无肿瘤复发,且7例患者GOS评分均达Ⅳ~Ⅴ级。结论内镜经鼻联合显微镜额眶颧颞入路处理复杂性颅内外沟通性肿瘤可一期切除肿瘤,手术并发症较少,具有较好的临床应用前景。     

Endoscopic transethmoidal sphenoidotomy

The posterior ethmoid and sphenoid sinuses often have significant anatomic variation resulting in operative challenges for the endoscopic surgeon. The hazards of surgery in this region are serious. Complications such as optic nerve and/or orbital trauma, and cerebrospinal fluid leak still occur despite increasing training and experience. Factors that lead to surgical complications include the lack of orientation within the dissection field and/or impaired visualization. Because minimally invasive sinus surgery is now being performed more frequently, surgical techniques designed to reduce the risk of complications are more important than ever. Anatomic landmarks that reliably orient the dissection within the posterior ethmoids and guide the surgeon to the sphenoid sinus could reduce such adverse outcomes. As with any surgical approach, it is better to rely on consistent anatomic landmarks within the operative field to perform the surgery safely, rather than rely on a range of measurements or adjunctive radiographic techniques, as described in many prior reports. The superior meatus and superior turbinate, skull base, and medial orbital wall are relatively reliable landmarks within the dissection field that can orient the surgeon. These anatomic landmarks allow safe dissection within the posterior ethmoid and a reliable approach to the sphenoid sinus, especially in patients undergoing revision surgery or in those with anatomic variations. The authors present their technique for the transethmoidal approach to the sphenoid sinus and discuss its advantages.