OBJECTIVE: In-depth understanding of endoscopic anatomy of the skull base is the cornerstone of the development of endoscopic endonasal skull base surgery. The purpose of this study is to explore the anatomical landmarks of the clivus for endoscopic endonasal skull base surgery. METHOD: Eight silicon-injected adult cadaveric heads (16 sides) were dissected performing endoscopic endonasal approach. The clivus and adjacent structures were exposed; and their anatomy shown in detail. High-quality pictures were produced. RESULT: The clivus was subdivided into the upper, the middle and the lower clivus. Extracranial soft tissue landmarks and bony landmarks were presented. Intradural landmarks of the upper clivus were the interpeduncular cistern, posterior cerebral artery, posterior communicating artery, superior cerebellar artery, cranial nerve III and cerebral peduncle; intradural landmarks of the middle clivus were the prepontine cistern, basilar artery, cranial nerve VI and pons; intradural landmarks of lower clivus were premedullary cistern, vertebral artery, cranial nerve XI and medulla oblongata. Surgical routes to the clivus were the upper clivus approach, middle clivus approach, lower clivus approach and panclival approach. CONCLUSION An understanding of the complex anatomy of the clivus is paramount for surgically dealing with the disease involved clivus and adjacent region.
Adult ; Cadaver ; Cranial Fossa, Posterior ; anatomy & histology ; surgery ; Endoscopy ; Humans ; Nose ; Skull Base

OBJECTIVETo identify the landmarks of transpterygoid approach and to report its application in a series of cases.

METHODSTwo silicon-injected adult cadaveric heads(4 sides) were dissected by performing an endoscopic endonasal transpterygoid approach after CT scanning for imaging guidance. High-quality pictures were obtained. This approach was used to treat twelve patients with skull base lesions including 3 spontaneous cerebrospinal fluid (CSF) leaks in the lateral recess of the sphenoid sinus, 2 neurofibromas and 2 Schwannomas involving the pterygopalatine fossa and infratemporal fossa, 1 dermoid cyst involving the middle fossa and infratemporal fossa, 1 invasive fungal sinusitis invading the middle fossa base, 1 basal cell adenoma in the upper parapharyngeal space, 1 chondrosarcoma in the parasellar region and 1 adenoid cystic carcinoma. Clinical records were reviewed.

RESULTSIn terms of approach dissection, important landmarks, such as the sphenopalatine foramen and artery, vidian canal and nerve, foramen rotundum and maxillary branch of trigeminal nerve, foramen ovale and mandibular branch of trigeminal nerve, as well as pterygoid segment of Eustachian tube were identified. In terms of clinical data, three patients with spontaneous CSF leak underwent repair. Six patients with benign lesions underwent complete tumor resection. In the patient with invasive fungal disease, thorough debridement was undertaken and antifungal drug was administered for one month. For these benign skull base lesions, there was no recurrence during the follow-up period. In the patient with chondrosarcoma, most of the tumor was removed in the first operation, and was followed by two endoscopic operations because of fast growth of the tumor. Final control was achieved with chemotherapy and radiation. In the patient with adenoid cystic carcinoma, tumor recurred five years after surgery, and was reoperated.

CONCLUSIONAn understanding of the landmarks of the transpterygoid approach is paramount for surgically dealing with disease located within and adjacent to the region of the pterygoid process of the sphenoid bone. The endoscopic endonasal transpterygoid approach is feasible and safe in selected patients with skull base lesions.

Adult ; Cerebrospinal Fluid Leak ; surgery ; Cranial Fossa, Middle ; pathology ; Dissection ; Endoscopy ; Eustachian Tube ; anatomy & histology ; Humans ; Nasal Cavity ; surgery ; Neoplasm Recurrence, Local ; Orbit ; anatomy & histology ; Otorhinolaryngologic Surgical Procedures ; methods ; Pterygopalatine Fossa ; pathology ; Skull Base ; anatomy & histology ; surgery ; Skull Base Neoplasms ; surgery ; Sphenoid Bone ; anatomy & histology ; Tomography, X-Ray Computed ; Trigeminal Nerve ; anatomy & histology

OBJECTIVEThe goal of the current study is to describe the transnasal endoscopic anatomy of the cavernous sinus and to provide the surgical approaches to this area.

METHODSSix silicon-injected adult cadaveric heads (12 sides) were dissected through endoscopic endonasal approach. The cavernous sinus and adjacent structures were exposed; detailed anatomies were demonstrated. High-quality pictures were produced.

RESULTSThe cavernous sinus had four walls, namely medial, lateral, posterior and superior walls. Five venous spaces within the sinus were identified by their relation to the carotid artery; those were the medial, lateral, posterosuperior, posteroinferior and anterolateral compartments. Three branches arising from the cavernous segment of internal carotid artery from proximal to distal were meningohypophyseal trunk, inferolateral trunk and McConnell capsular artery. Cavernous sinuses communicated each other by intercavernous sinuses, as well as basilar sinus in middle line, and connected with superior and inferior petrosal sinuses. The third and fourth nerves coursed in superior part of the lateral wall of the cavernous sinus; Meckel's cave located in the posteroinferior part of the lateral wall of the cavernous sinus; V1 sloped to the superior orbital fissure along the lateral wall; the sixth nerve entered the posteroinferior compartment then passed through the internal carotid artery and reached to superior orbital fissure. The approaches to the cavernous sinus included trans-sphenoid-sellar-medial cavernous sinus (medial to the internal carotid artery) and trans-ethmoid-pterygoid-sphenoid-lateral cavernous sinus (lateral to the internal carotid artery). Trans-sphenoid-sellar-medial cavernous sinus approach was able to expose medial compartment and posterosuperior compartment and part of posteroinferior compartment. Trans-ethmoid-pterygoid-sphenoid-lateral cavernous sinus approach was able to expose anteroinferior compartment, lateral cavernous sinus and cranial nerves in lateral wall.

CONCLUSIONAn understanding of the complex relationships of the cavernous segment of internal carotid artery and cranial nerves in cavernous sinus is paramount for surgically dealing with the disease involved cavernous sinus and adjacent region.

Cavernous Sinus ; anatomy & histology ; surgery ; Endoscopy ; Humans ; Skull Base ; anatomy & histology ; surgery ; Sphenoid Sinus ; anatomy & histology ; surgery