Surgical anatomy of the natural ostium of the sphenoid sinus

OBJECTIVES: This study was undertaken to measure the distance and the angle between the anterior part of nasal cavity and the natural ostium of the sphenoid sinus. The anatomical location of the natural ostium according to the direction of surgeon's operating view toward the anterior wall of the sphenoid sinus was also analyzed. STUDY DESIGN: This study used careful cadaver dissection under a surgical microscope. METHODS: One hundred sagittally sectioned adult cadaveric heads were used. We measured the distances and angles for identifying the natural ostium of the sphenoid sinus using several reference points such as the limen nasi, the sill, and the posteroinferior end of the superior turbinate. In addition, we tried to identify whether the location of the natural ostium is medial or lateral to the posterior end of the superior turbinate. RESULTS: The natural ostium of the sphenoid sinus was located at an angle of 35.9 degrees with a distance of 56.5 mm from limen nasi and at an angle of 34.3 degrees with a distance of 62.7 mm from nasal sill. It was located approximately 1 cm above the posteroinferior end of the superior turbinate and at a medial aspect to the posterior end of the superior turbinate in 83% of specimens. CONCLUSIONS: We speculate that the posteroinferior end of the superior turbinate is the best landmark for identifying the natural ostium of the sphenoid sinus. Furthermore, the natural ostium should ideally be searched from a superior and medial aspect in relation to the posteroinferior end of the superior turbinate.     

Surgical measurement to sphenoid sinus for the Chinese in Asia based on CT using sagittal reconstruction images

The objective this study was to measure the changes of sphenoid sinusin the Chinese in AsiausingCT sagittal thin-slice reconstruction images, and to clarify the three-dimensional anatomical features of sphenoid sinus with its surrounding structures, relevant to the performing of the endoscopic sphenoidotomy. The sagittal reconstruction images were obtained from 178 CT images of 89 cases of normal adult participants (54 males and 35 females) with sphenoid sinus. We took the high-resolution axial CT images, from all the subjects, of the thickness by 0.625 mm, and reconstructed 1-mm-thick gapless sagittal CT images to measure the distance of all the sellar and pre-sellar types on the three-dimensional reconstructable sagittal plane under the bone window (4,000 at its width, and 400 at its level) in the CT images. The length of mean vertical line from the center of sphenoid ostium to the roof of sphenoid sinus of Non Onodi cell type is 10.6 ± 1.5 mm, and of Onodi cell type is 3.3 ± 1.5 mm. The length of vertical line from the center of sphenoid ostium to the lowest level of the bottom of sphenoid sinus is 12 mm ± 3.7 mm. The length of mean horizontal line from the sphenoid ostium to the posterior wall of sphenoid sinus is 18 ± 1.5 mm or 28 ± 2.5 mm. The mean horizontal line from the lowest point of the sella to the anterior wall of sphenoid sinus is 17.5 ± 1.3 mm in length. The mean horizontal distance from anterior wall to posterior wall of sphenoid sinus of Non Onodi cell type lining skull base is 10.1 ± 1.0 mm, and of Onodi cell type, is 5.2 ± 4.3 mm. The longest horizontal distance from the anterior wall to the posterior wall of sphenoid sinus is 22.0 ± 7.7 mm. The present study provides atomical information about sphenoid sinus of the Chinese in Asia with some surgical distance measured between the sphenoid ostium and the surrounding structures, which is essential to avoid the complications during surgery.     

The sphenoid sinus natural ostium is consistently medial to the superior turbinate

BACKGROUND: This study was performed to determine the location of the natural ostium of the sphenoid sinus relative to the intact superior turbinate. METHODS: Forty-seven cadaveric specimens were examined. Mucosa over the sphenoethmoidal recess, superior turbinate, and posterior ethmoid was left intact. The position of the sphenoid sinus natural ostium relative to the superior turbinate was identified. RESULTS: The sphenoid ostium was identified in all specimens. In all specimens, the sphenoid ostium was found to be medial to the intact superior turbinate, notwithstanding lateral deflection of the posterior few millimeters of the superior turbinate in some cases. CONCLUSION: The superior turbinate is an excellent landmark for the sphenoid sinus natural ostium. Previous observations of the ostium positioned lateral to the superior turbinate may have been caused by stripping of the superior turbinate mucosa before measurements were taken. In the intact specimen, the sphenoid ostium is reliably found medial to the superior turbinate.     

Analysis of sphenoid sinus in the operative plane of endoscopic transsphenoidal surgery using computed tomography

Recently, the endoscopic transsphenoidal approach for sphenoid sinus or intracranial lesion has gained more popularity and the study of the surgical anatomy and relationships of the sphenoid sinus has gained increased significance. The aim of this study was to clarify the anatomical features of the sphenoid sinus including surrounding structures as seen in the operative view of endoscopic transsphenoidal surgery. The various distances in the sphenoid sinus as well as the relationships between the sphenoid sinus ostium (SO) and important structures such as the optic canal (OC) and carotid artery (CA) according to the presence of Onodi cell (sphenoethmoidal cell; Onodi group vs. non-Onodi group) were assessed using multiplanar and three-dimensional model of CT scans in 100 patients. The SO was more inferior in Onodi group and located superior to the lowest point of the sella. The horizontal distance from the SO to sella was approximately 13 or 14 mm depending on the existence of Onodi cells. Regardless of Onodi cell, the whole course of the OC in the sinus ran superolaterally to inferomedially in the endoscopic view. However, Onodi cell made the angles from the SO to OC larger. In Onodi group, the CA was located from the SO in a superolateral direction, but in non-Onodi group, the CA was located from the SO in the inferolateral direction. This study provides anatomical information about the sphenoid sinus, with important surgical distances between the SO and surrounding structures measured, which is essential to avoid complications during transsphenoidal surgery.     

Endoscopic anatomy of the sphenoid sinus.

The anatomy of the sphenoid sinus, as it relates to endoscopic sinus surgery, was studied in 93 cadaver heads (186 sphenoid sinuses) using endoscopic dissections as well as sagittal sections. The relationship of the sphenoid sinuses to the carotid artery, optic nerve, floor of sella turcica, as well as other important structures, were verified and discussed. The recesses of the sinus as well as its ostium and accessory septa and crests were described and their clinical importance was discussed. Pertinent measurements were included wherever appropriate.     

鼻内镜蝶窦开放术的薄层断层解剖学研究

目的 为安全的进行鼻内镜下蝶窦开放术提供薄层断层解剖学资料。方法 通过冰冻铣切技术获得层厚为0．1mm的连续横断面断层解剖图像,对蝶窦及其重要毗邻结构进行观察和测量。结果 46.7%视神经管以及70%颈内动脉在蝶窦外侧壁处形成突起。蝶窦口上下径为（3.41±0.56）mm,左右径为（2.24±0.35）mm,蝶窦口与颈内动脉、视神经管间的距离分别为（19.63±2.26）mm、（8.83±1.42）mm。结论 通过对蝶窦连续横断面薄层断层解剖图像的追踪观察,可以获得蝶窦及其重要毗邻结构的相关数据。     

A cadaveric model for balloon-assisted endoscopic paranasal sinus dissection without fluoroscopy

BACKGROUND: Recently, balloon catheter (BC) dilatation of paranasal sinus ostia has been introduced. In this procedure, a balloon-tipped catheter is placed across a sinus ostium over a flexible wire under fluoroscopic guidance, and inflation of the balloon enlarges the ostium. Some rhinologists have criticized this procedure for its failure to remove tissue and bone, especially in the setting of sinonasal polyposis. This project seeks to develop strategies for incorporating BC technology into standard functional endoscopic sinus surgery procedures. METHODS: Endoscopic sinus dissection of three human cadaveric heads was performed with conventional instruments supplemented by lacrimal duct BCs (LacriCATH; Quest Medical, Allen, TX). No fluoroscopy was used. Each dissection was videotaped for later review. RESULTS: For frontal recess dissection, these steps were performed under endoscopic visualization: (1) passage of the BC between frontal recess partitions, (2) BC inflation, and (3) removal of fractured frontal recess partitions with conventional instruments. This approach was used successfully in each frontal recess. Under endoscopic visualization, a BC was passed into the sphenoid ostium and inflated; this maneuver successfully dilated each sphenoid ostium. It was not feasible to reliably pass the BC through the natural maxillary ostium. Each BC was inflated to 8 atm for 30 seconds. No evidence of orbital or skull base injury was noted. No fluoroscopy was used. CONCLUSION: BCs may be used as adjunctive instrumentation for endoscopic sinus dissection without fluoroscopy. This strategy warrants additional technical and clinical development.     

鼻内镜下经上鼻道径路处理孤立性蝶窦病变

目的探讨鼻内镜下处理孤立性蝶窦病变的方法及疗效。方法回顾分析1999年8月~2004年10月93例孤立性蝶窦病变病人在鼻内镜下经上鼻道径路行孤立性蝶窦病变处理。鼻内镜下切除上鼻甲后半部分,直接暴露蝶窦前壁及开口,扩大开口,处理蝶窦病变。结果所有病例均顺利完成手术,无1例发生严重并发症。随访1~2年,蝶窦炎、蝶窦脓肿、蝶窦黏液囊肿、真菌性蝶窦炎、蝶窦息肉等88例病人均无复发。其余5例病人中1例真菌性蝶窦炎术后不久侵入颅内,后经抗真菌及综合治疗痊愈;2例蝶窦顶后壁脑脊液鼻漏1次性修补成功;1例蝶窦侧壁脑脊液鼻漏修补失败;1例蝶窦血管瘤未愈。结论鼻内镜下经上鼻道进路是处理孤立性蝶窦病变安全、直接、微创、有效的治疗方法。     

Sphenoid sinus symmetry and differences between sexes

OBJECTIVES: To evaluate the anatomic variations of neurovascular structures adjacent to the sphenoid sinus and their agreement between right and left sides as well as differences between sexes. METHODS: Forty-five cadavers were dissected (24 men, and differences between sexes and agreement of anatomic variations of the sphenoid sinus between sides were analyzed. RESULTS: The mean distance from the sphenoid sinus ostium to the anterior nasal spine was greater in males than in females by an average of 3.0 mm (p = 0.001) while the mean difference of distances between the right and left side was -1.1 +/- 3.1 mm. Female cadavers had a greater frequency of optic-carotid recess (p = 0.04) and dehiscence over the maxillary nerve (p = 0.02), as well as greater relative risk of optic nerve protrusion (p < 0.001), and dehiscence over the internal carotid artery (ICA) (p = 0.002). In male cadavers the intersinus septum was inserted on the course of the ICA 3.5 times more often than in female (p = 0.02). Agreement of anatomic variations between sides ranged from moderate to almost perfect depending on the structures evaluated. CONCLUSIONS: There are anatomic differences of the sphenoid sinus between sexes and between right and left sides, and these differences should be taken into consideration during surgery.     

Surgical anatomy of the optic nerve and the internal carotid artery in the lateral wall of the sphenoid sinus. An anatomic study of the cranial base]

The optic nerve and the internal carotid artery lying in the cavernous sinus contact the bony wall of the sphenoid sinus, and can easily be injured during surgery. The maxillary sinus, the sphenoid sinus and the ethmoid cells were opened on both sides during ten resections of the skull base. After removing the bony part of the lateral wall of the sphenoid sinus the following measurements were performed: the distance between the optic nerve and the frontal dura; the distance between the optic nerve and the internal carotid artery; the length and width of the optic nerve and the internal carotid artery in the area contacting the bony wall of the sphenoid sinus. This study illustrates the regularity of the structures of the posterior nasal wall. Landmarks are offered for finding the orbital aperture of the optic canal. The necessity of orientation by landmarks is emphasized.     

鼻内鼻窦手术损伤泪道的解剖学分析

为了减少或避免易内鼻窦手术损伤泥道，在20具成人尸头标本上，观测泪道与鼻腔外侧壁的毗邻关系。发现前筛气房与泪囊窝关系密切，气房侵及泪骨占87．5％；鼻泪管与钩突上端游离线之间距离为6.74±1．72mm，距离筛漏斗前界3．44±0．75mm，距上颌窦鼻内开口为5．50±3．73mm。鼻泪管开四位于下鼻道前端鼻甲附着处。研究表明，前筛房、钩突切除和上颌窦鼻内开窗手术范围，如果过于向前，容易损伤泪道。     

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.     

蝶窦外侧壁的应用解剖

６３侧尸头解剖测量结果表明，蝶窦外侧壁上颈内动脉骨性隆起可分为①鞍前段，其长度、骨质厚度及至中线距离的均值分别为６．８、１．０、６．２ｍｍ；②鞍下段，其长度、骨质厚度及至中线距离的均值分别为６．６、１．０、５．０ｍｍ；③鞍后段，其长度、骨质厚度及至中线距离的均值分别为６．６、１．８及７．１ｍｍ。视神经管隆起的长度，骨质厚度及至中线距离的均值分别为４．８、１．０、５．５ｍｍ。上颌神经隆起的长度，骨质厚度及至中线距离的均值分别为５．３、１．２、８．５ｍｍ。     

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.     

原发于蝶窦外侧隐窝囊肿的诊断与鼻内镜手术治疗

目的　探讨原发于蝶窦外侧隐窝囊肿的临床特征及鼻内镜治疗的疗效。方法　回顾性分析我院2007～2015年间收治的9例原发于蝶窦外侧隐窝囊肿患者的临床资料及术后随访结果。其中7例患者以面颊部麻木感为主诉,2例患者进行性视力下降为主诉;头面部均无明显阳性体征。均于全麻内镜下经蝶窦入路行囊肿开窗引流术。结果　所有患者术中及术后均无并发症发生,术后症状均消失。随访6～24个月,所有患者的囊肿引流口均与蝶窦相通形成永久性引流口,无闭塞或复发。结论　①原发于蝶窦外侧隐窝囊肿的有其独有的症状及影像学特征,区别于一般的蝶窦囊肿;②鼻内镜下经蝶窦入路行囊肿开窗切除术是治疗原发于蝶窦外侧隐窝囊肿的微创、安全、有效术式。     

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.     

The maxillary line: anatomic characterization and clinical utility of an important surgical landmark

OBJECTIVES: The maxillary line is a mucosal projection along the lateral nasal wall that serves as a landmark for endoscopic sinus and orbital procedures. The anatomic relations of this structure are not well described. We sought to define the anatomy of the maxillary line and explore its clinical utility. STUDY DESIGN: Cadaver dissection/case series. METHODS: Twenty-five cadaveric nasal specimens were dissected. Extranasal and intranasal measurements of structures including the lacrimal crests, sac and duct, the suture line between the maxillary and lacrimal bones, and the maxillary sinus ostium were taken. The mid-point of the maxillary line, termed the "M point," was used for reference. The distance from the nasal sill to the M point was measured in 30 consecutive clinic patients. RESULTS: The maxillary line corresponded intranasally to the junction of the uncinate and maxilla and extranasally to the suture line between the lacrimal bone and maxilla within the lacrimal fossa. This suture was approximately half way between the anterior and posterior crests. Axially, the plane of the M point corresponded to the superior margin of the maxillary sinus ostium posteriorly (average 10 mm) and was just inferior to the lacrimal sac-duct junction anteriorly. In live subjects, the M point was approximately 3.9 cm from the nasal sill in women and 4.8 cm in men. CONCLUSION: Understanding the conserved relationships of the maxillary line and M point with adjacent nasal and orbital structures will ensure the complete removal of the uncinate process during uncinectomy and promote safe and ample exposure of the lacrimal sac during endoscopic dacryocystorhinostomy.     

蝶窦冠状位薄层断层解剖学研究

目的 对蝶窦进行冠状位薄层断层解剖学研究。方法 通过冰冻铣切技术获得层厚为0．1mm的连续冠状位断层解剖图像观察蝶窦及其重要毗邻结构。结果 75%的蝶窦为鞍型,蝶窦中隔居中者为15%,60%视神经管以及75%颈内动脉在蝶窦外侧壁处形成突起。结论 通过对蝶窦连续冠状位薄层断层解剖图像的追踪观察可以为安全行蝶窦开放术提供蝶窦及其重要毗邻结构的相关资料。     

侧颅底塑化断层解剖及计算机辅助三维重建研究

目的：探讨侧颅底结构的断层解剖学特征，为此区域的病变和手术方法的选择提供解剖学依据。方法：采用生物塑化技术制作三套冠状面侧颅底结构的薄层切片，观察测量各个层面上重要结构的位置、毗邻关系，并用计算机提取图像后进行三维重建。结果：采用塑化技术制作的切片可以清晰显示侧颅底的骨质、肌肉、血管和神经等结构。侧颅底的结构可以通过上颌窦中部切面、咽鼓管咽口切面、卵圆孔切面、咽鼓管鼓口切面和内昕道切面分别展示，通过计算机对正常人侧颅底区域塑化薄层连续切片进行信号标定、提取和三维重建，成功地获得了蝶窦、三叉神经及其分支、颈内动脉、咽鼓管的离体图像。结论：薄层断面解剖可以准确定位侧颅底区域的重要结构及相互位置关系，三维重建图像形象逼真、准确，对侧颅底外科手术具有重要的意义。