[Study on the consistency between CBCT image features of sphenopalatine foramen and those seen in nasal endoscopy].

Objective:To study the clinical anatomy of the sphenopalatine foramina by dissecting the sphenopalatine foramina during Vidian nerve branch neurotomy. The anatomy and CBCT images of sphenopalatine foramen were analyzed to facilitate the navigational of clinical operation using CBCT images. Methods:From October 2017 to September 2023, 84 cases（168 sides） of Vidian nerve branch neurotomy in our department were collected. The clinical summary was made according to the anatomy of sphenopalatine foramen during the operation. Preoperative CBCT imaging findings of the sphenopalatine foramina were also studied. Results:The clinical anatomy of sphenopalatine foramen could be divided into four types: middle meatus type（1.19%）, trans-meatus type（62.29%）, superior meatus type（33.33%） and double foramen type（1.19%）. The incidence of ethmoidal ridge was 98.81%. The distance from sphenopalatine foramina to posterior nasal canal were（14.63±2.66） mm to left and（14.65±2.63） mm to right, The position Angle ∠a of lower margin of sphenopalatine foramina were（62.36±10.05）° to left and（61.51±11.82）° to right, respectively. Axial CT images can be used to divide the sphenopalatine foramen into five levels: the upper edge of the sphenopalatine foramen level, the Vidian nerve level, the basal plate interaction level, the lower edge of the sphenopalatine foramen level and the pterygopalatine canal level. The agreement between endoscopic anatomy of sphenopalatine foramen and imaging navigation was 100%. Conclusion:The sphenopalatine foramina exhibit various anatomical types. The preoperative navigational CBCT reading can effectively identify the type of sphenopalatine foramina, guide the choice of surgical method, and help avoid serious complications. This has significant clinical application value.

Morphometry and Intracranial Relations of the Sphenoid Sinus in Context to Endoscopic Transnasal Transsphenoidal Surgery.

Introduction Due to the variable degree of pneumatization, the shape and size of the sphenoid sinus are irregular. An endoscopic intranasal transsphenoidal approach is made in sphenoid sinus pathologies, sphenoid sinusitis, and sellar and parasellar diseases. A diagnostic approach to the sphenoid sinus is also done to get a better MRI scan of the pituitary. The present study aims to describe the variant types of sphenoid sinus, morphometry, anatomy, and relations of sphenoid sinus, which will be helpful to surgeons during an endoscopic approach to the sphenoid sinus. Materials and methods We studied 76 cadaveric sphenoid sinuses that were exposed by taking a sagittal section of 38 formalin-fixed cadaveric heads. After examining the inter-sphenoidal septum, it was removed to observe the inside aspect of the sphenoid sinus. Different dimensions of the sinus were noted down. The bulges inside the sinus due to neurovascular structures in relation to the sinus were observed. Results  The most prominent type found was the sellar in 68.4% of cases preceded by the postsellar in 23.7% of cases. Presellar type of pneumatization was seen only in 7.9% of cases and the conchal type was absent. Intersphenoid septum was seen in 92,1% of cases, out of which 11.4% of septums were deficient on the posterior aspect. An internal carotid artery bulge in the sphenoid sinus was seen in 46% of cases. In 27.6% and 19.7% of sphenoid sinuses, bulging of the optic and vidian nerves, respectively, were seen. Some of these structures were dehiscent in the sphenoid sinus. Conclusions To get more space in the sphenoid sinus, the septa in the sinus are removed by surgeons, which may damage the walls of the sphenoid sinus. Knowledge of the relations of neurovascular structures with the sphenoid sinus will be helpful to surgeons during the transsphenoidal endoscopic approach to avoid any injury to these structures.

The anterolateral triangle as window on the foramen lacerum from transorbital corridor: anatomical study and technical nuances.

OBJECTIVE: Neurosurgical indications for the superior eyelid transorbital endoscopic approach (SETOA) are rapidly expanding over the last years. Nevertheless, as any new technique, a detailed knowledge of the anatomy of the surgical target area, the operative corridor, and the specific surgical landmark from this different perspective is required for a safest and successful surgery. Therefore, the aim of this study is to provide, through anatomical dissections, a detailed investigation of the surgical anatomy revealed by SETOA via anterolateral triangle of the middle cranial fossa. We also sought to define the relevant surgical landmarks of this operative corridor. METHODS: Eight embalmed and injected adult cadaveric specimens (16 sides) underwent dissection and exposure of the cavernous sinus and middle cranial fossa via superior eyelid endoscopic transorbital approach. The anterolateral triangle was opened and its content exposed. An extended endoscopic endonasal trans-clival approach (EEEA) with exposure of the cavernous sinus content and skeletonization of the paraclival and parasellar segments of the internal carotid artery (ICA) was also performed, and the anterolateral triangle was exposed. Measurements of the surface area of this triangle from both surgical corridors were calculated in three head specimens using coordinates of its borders under image-guide navigation. RESULTS: The drilling of the anterolateral triangle via SETOA unfolds a space that can be divided by the course of the vidian nerve into two windows, a wider "supravidian" and a narrower "infravidian," which reveal different anatomical corridors: a "medial supravidian" and a "lateral supravidian," divided by the lacerum segment of the ICA, leading to the lower clivus, and to the medial aspect of the Meckel's cave and terminal part of the horizontal petrous ICA, respectively. The infravidian corridor leads medially into the sphenoid sinus. The arithmetic means of the accessible surface area of the anterolateral triangle were 45.48 ± 3.31 and 42.32 ± 2.17 mm2 through transorbital approach and endonasal approach, respectively. CONCLUSION: SETOA can be considered a minimally invasive route complementary to the extended endoscopic endonasal approach to the anteromedial aspect of the Meckel's cave and the foramen lacerum. The lateral loop of the trigeminal nerve represents a reliable surgical landmark to localize the lacerum segment of the ICA from this corridor. Nevertheless, as any new technique, a learning curve is needed, and the clinical feasibility should be proven.

Vidian nerve neurofibroma.

Vidian nerve is created from the connection of the greater petrosal nerve and the deep petrosal nerve (Giraddi et al., 2010). These two nerves transmit parasympathetic and sympathetic fibers respectively. Vidian nerve tumour is one of the rarest known tumours (Hong et al., 2014). Genetic changes effectively play a role in the development of nerve sheath tumors. Of course, due to the rarity of this type of tumor, there is not much information about its causes and risk factors (Yamasaki et al., 2015). The incidence rate of malignant peripheral nerve sheath tumors is about 0.001 % (Fortes et al., 2019). Considering the low prevalence of this tumor and the type of treatment performed on this patient, the investigation of the case presented in this study can lead to a better understanding and more correct treatment. This case report has been proposed due to the very low prevalence of neurofibroma of the Vidian nerve in the world. Vidian nerve supplies sympathetic and parasympathetic fibers to the lacrimal glands and nasopalatine mucosa. In many cases, involvement of the Vidian nerve by neurofibroma can be misleading for doctors. Due to the very low prevalence of neurofibroma of the Vidin nerve, the possibility of its being missed and not diagnosed during the examination of patients by doctors is very high. This case report is presented in order to familiarize scientists with this lesion due to its very low prevalence. This therapeutic approach that was used in this case requires longer follow-up periods, but it can prevent possible complications after surgery.

Endonasal Exposure of Lateral Recess of the Sphenoid Sinus: Significance of Pterygoid Process Pneumatization.

BACKGROUND: Caudal pneumatization of the pterygoid process may impact endonasal exposure of the lateral recess of sphenoid sinus (LRSS). OBJECTIVES: This study aims to explore the implications of a pneumatized pterygoid process for an endonasal transpterygoid approach to the LRSS and to define strategies regarding the preservation or sacrifice of the vidian nerve. METHODS: Dissection of the LRSS (11 sides) was performed on 6 cadaveric specimens, preselected for the radiographic presence of an LRSS. In addition, the dimensions of the LRSS were measured on the deidentified CT images of 120 patients (240 sides). The sphenoid sinus was subdivided into 3 categories: Type 1 (no identifiable LRSS), Type 2 (lateral pneumatization of the greater wing above the vidian canal), and Type 3 (pneumatization of both the greater wing and the pterygoid process). RESULTS: On the cadaveric specimens, a Type 2 pneumatization often allowed access to the LRSS above the level of the vidian canal; thus, sparing the vidian neurovascular bundle. In Type 3 pneumatization, a frontal corridor through the pterygoid base could be created to reach the LRSS with preservation of the vidian nerve. Extreme Type 3 pneumatization, however, required the transposition or sacrifice of the vidian nerve to facilitate a full direct access to the superolateral LRSS. Measurements on CT images revealed that the extent of caudal pneumatization of the pterygoid process had no statistically significant correlation with the superolateral extension of the lateral recess in patients with Type 3 LRSS (P > .05). CONCLUSION: Pneumatization of the LRSS toward a caudal or superolateral direction may develop independent from each other. Caudal pneumatization of the pterygoid process seems to variably impact the endonasal exposure of the LRSS.

[A vidian neurectomy approach with the sphenoid process of the palatine bone as a landmark].

Objective:To explore a safe and effective surgical approach to locate and cut the vidian nerves with the sphenoid process of the palatine bone as a landmark. Methods: The landmarks of locating the external opening of the vidian canal were confirmed by the dissection of the cadaveric heads, and the feasibility of locating the vidian nerves with the determined landmarks was verified during operation. Results:The anatomical landmarks, which are the anterior opening of palatovaginal canal, the posterior opening of palatovaginal canal, palatovaginal canal and the nasal pharyngeal crest of the root of the pterygoid process can be used as the important landmarks of locating vidian nerve. In the cases of 10 patients with refractory allergic rhinitis and vasomotor rhinitis, the vidian nerves were successfully located and sectioned, and one patient was complicated with short-term unilateral palatal numbness after surgery. Conclusion:The anterior opening of palatovaginal canal, the posterior opening of palatovaginal canal, palatovaginal canal and the nasal pharyngeal crest of the root of the pterygoid process can be used as surgical markers for vidian neurectomy with the sphenoid process of the palatine bone as landmarks.

Anatomical Variants of Post-ganglionic Fibers within the Pterygopalatine Fossa: Implications for Endonasal Skull Base Surgery.

Objectives The vidian nerve provides parasympathetic innervation to the nasal cavity and the lacrimal gland. Previous anatomic studies have primarily focused on preservation or severance of the vidian nerve proximal to the pterygopalatine ganglion (PPG). This study aimed to assess its neural fibers within the pterygopalatine fossa after synapsing at the PPG, and to explore potential clinical implications for endoscopic endonasal skull base surgery. Methods An endonasal transpterygoid approach was performed on eight cadaveric specimens (16 sides). The PPG and maxillary nerve within the pterygopalatine fossa were divided. The vidian nerve was traced retrograde into the foramen lacerum, and postganglionic fibers distal to the PPG were dissected following the zygomatic nerve into the orbit. Potential communicating branches between the ophthalmic nerve (V1) and the PPG were also explored. Results All sides showed a plexus of neural communications between the PPG and the maxillary nerve. The zygomatic nerve exits the maxillary nerve close to the foramen rotundum, piercing the orbitalis muscle to enter the orbit in all sides. The zygomatic nerve was identified running beneath the inferior rectus muscle toward a lateral direction. In 7/16 sides (43.75%), a connecting branch between V 1 and the pterygopalatine ganglion was observed. Conclusion Neural communications between the PPG and the maxillary nerve were present in all specimens. A neural branch from V 1 to the PPG potentially contributes additional postganglionic parasympathetic function to the lacrimal gland.

Sphenoid Sinus and Related Neurovascular Structures-Anatomical Relations and Variations on Radiology-A Retrospective Study.

The aim of this study was to evaluate sphenoid sinus pneumatisation and its anatomical relation with adjacent neurovascular structures in Indian population. We performed a retrospective cross-sectional study, in which the pattern of sphenoid sinus pneumatization was studied on high-resolution computed tomography scans (n = 400), and association of the optic nerve, vidian canal and foramen rotundum along with related morphometric measurements were studied. Out of 400 CT scans, 60.5% were males. Majority had sellar type of pneumatization (89.5%) and single intersinus septum (68%). The most common configuration of relation of optic nerve canal was DeLano type 2 (34.75%). Vidian canal (VC) and Foramen rotundum (FR) were found dehiscent in 40.5% and 6.38% respectively. Average distance of FR from midline on right and left side was 16.3 ± 2.19 mm and 16.7 ± 2.23 mm respectively. Average distance of VC from midline on right and left side was 12.4 ± 5.84 mm and 12.4 ± 4.18 mm respectively. Average right FR to VC distance was 4.17 ± 2.16 mm and left FR to VC was 4.44 ± 2.20 mm. Anatomical variations of the sphenoid sinus are well known. In the present study, we have tried to highlight the importance of knowledge of various anatomical variations in relations to sphenoid sinus as they are critical in planning of surgery. Pre-operative radiological study and correlation is inevitable to assess type and extent of sinus pneumatisation, bony dehiscence and septal terminations to avoid injury to vital structures.

OnabotulinumtoxinA injection towards the SPG for treating symptoms of refractory chronic rhinosinusitis with nasal polyposis: a pilot study.

BACKGROUND AND OBJECTIVE: The main objective of this prospective, open, uncontrolled pilot study was to investigate the safety of administering onabotulinumtoxinA (BTA) towards the sphenopalatine ganglion (SPG) in 10 patients with refractory chronic rhinosinusitis with nasal polyposis (CRSwNP) using a novel injection tool, the MultiGuide®. MATERIAL AND METHODS: A one-month baseline period was followed by bilateral injections of 25 U BTA in the SPG and a follow-up of 12 weeks. The primary outcome was adverse events (AE), and the main efficacy outcome was a 50% reduction in visual analogue scale (VAS) symptoms for nasal obstruction and rhinorrhea in months 2 and 3 post-treatment compared to baseline. RESULTS: We registered 13 AEs, none of which were serious, however, one patient experienced diplopia which moderately affected his daily activities. The symptoms slowly improved and resolved 4 weeks after injection. Five patients were treatment responders with at least 50% median reduction in the nasal obstruction, and four were treatment responders concerning rhinorrhea. CONCLUSIONS: Injection of BTA toward the SPG using the MultiGuide® in patients with CRSwNP appears to be safe but with a potential for moderately disabling side effects. The study indicates a beneficial effect on nasal obstruction.

Variant neurovascular relations of the sphenoid sinus in adult Nigerians.

BACKGROUND: With the advent of endoscopic sinus surgery, the variant neurovascular relations of the sphenoid sinus are important to surgeons to minimise the iatrogenic complications. This study elucidates the variant neurovascular relations of the sphenoid sinus in adult Nigerians. MATERIALS AND METHODS: This study was conducted at the Radiology Department of Delta State University Teaching Hospital after institutional approval. Brain computed tomography images of 336 patients, aged ≥20 years and spanning over 5 years' duration were utilised. We evaluated the sphenoid sinus for protrusion and dehiscence of neurovascular structures bilaterally. The position of the optic nerve in relation to the sinus was classified from Type 0-4. The Statistical Package for the Social Sciences software version 23 was used for the data analysis. The Chi-square test was used to probe for the association between the variants with regard to side and gender. P < 0.05 was considered statistically significant. RESULTS: Dehiscence and protrusion of the internal carotid artery (ICA) occurred in 34, 10.1% and 83, 24.7% patients correspondingly. The dehiscence of optic, maxillary and Vidian nerves was (26, 7.7%), (60, 17.9%), and (53, 15.8%), whereas the frequency of their protrusion was (50, 14.9%), (76, 22.6%) and (87, 25.9%), respectively. All these variants except the ICA and maxillary nerve dehiscence showed a significant association with the side of occurrence (P = 0.001). Out of the 672 optic canals evaluated bilaterally, a preponderance of Type I (534, 79.5%) was observed followed by II (96, 14.3%), IV (35,5.2%), III (7, 1.0%) and Type 0 (0, 0%). CONCLUSION: Our study has shown that the neurovascular relations of the sphenoid sinus vary from previously documented reports, thus confirming the need for pre-operative evaluation.

Association between the developing sphenoid and adult morphology: A study using sagittal sections of the skull base from human embryos and fetuses.

The developing sphenoid is regarded as a median cartilage mass (basisphenoid [BS]) with three cartilaginous processes (orbitosphenoid [OS], ala temporalis [AT], and alar process [AP]). The relationships of this initial configuration with the adult morphology are difficult to determine because of extensive membranous ossification along the cartilaginous elements. The purpose of this study was therefore to evaluate the anatomical connections between each element of the fetal sphenoid and adult morphology. Sagittal sections from 25 embryos and fetuses of gestational age 6-34 weeks and crown-rump length 12-295 mm were therefore examined and compared with horizontal and frontal sections from the other 25 late-term fetuses (217-340 mm). The OS was identified as a set of three mutually attached cartilage bars in early fetuses. At all stages, the OS-post was continuous with the anterolateral part of the BS. The BS included the notochord and Rathke's pouch remnant in embryos and early fetuses. The dorsum sellae was absent from embryos, but it protruded from the BS in early fetuses before a fossa for the hypophysis became evident. Although not higher than the hypophysis at midterm, the dorsum sellae elongated superiorly after gestational age 25 weeks. In early fetuses, the AP was located on the side immediately anterior to the otic capsule. The AT developed on the side immediately posterior to the extraocular rectus muscles. At late term, the greater wing was formed by membranous bones from the AT and AP. The AT and AP formed a complex bridge between the BS and the greater wing. A small cartilage, future medial pterygoid process (PTmed) was located inferior to the AT in early fetuses. At midterm, one endochondral bone and multiple membranous bones formed the PTmed. The lateral pterygoid process (PTlat) was formed by a single membranous bone plate. Therefore, we connected fetal elements and the adult morphology as follows. (1) Derivative of the OS makes not only the lesser wing but also the anterior margin of the body of the sphenoid. (2) Derivatives of the BS are the body of the sphenoid including the sella turcica and the dorsum sellae. (3) Most of the greater wing including the foramen rotundum and the foramen oval originate from the AT and AP and multiple membranous bones. (4) The PTmed originate from endochondral bones and multiple membranous bones, while the PTlat derive from a single membranous bone.

Endoscopic Endonasal Surgery of a Large Vidian Nerve Schwannoma With Preparation for Avoiding Major Vascular Injury.

Vidian nerve schwannomas are extremely rare, and their surgical management requires an awareness of the surrounding vascular and nervous systems, including the internal carotid artery. Herein, we report a case of a vidian nerve schwannoma that was successfully removed using an endoscopic endonasal approach in a 21-year-old patient who presented with lacrimal hyposecretion. Imaging revealed a large mass extending to the middle cranial fossa posteriorly, to the pterygopalatine fossa laterally, and to the sphenoid sinus medially. The paraclival and petrosal portions of the internal carotid artery were displaced posteriorly. Endoscopic observation of the right nose demonstrated anterior displacement of the inferior portion of the middle turbinate. Based on the above, we suspected a vidian nerve schwannoma, and endoscopic endonasal surgery was performed with particular attention to avoid vascular injuries. An endoscopic transmaxillary approach was used to expose the anterior surface of the tumor. After confirming the pathological diagnosis intraoperatively, intracapsular resection of the tumor was completed using an ultrasonic surgical aspirator with Doppler monitoring of the location of the internal carotid artery. Endoscopic management of the surgical field and preparation to avoid vascular injury are essential for safe and efficient tumor resection.

Extradural anterior temporal fossa approach to the paranasal sinuses, nasal cavities through the anterolateral and anteromedial triangles: Combined microscopic and endoscopic strategy.

OBJECTIVE: To demonstrate the utility and limitations of the extradural endoscopic-assisted anterior temporal fossa approach to the pterygopalatine fossa (PPF), infratemporal fossa (ITF), paranasal sinuses (PS), parapharyngeal region (PPR), nasal cavities (NC), epipharynx (EP), and clivus. METHODS: A frontotemporal orbitozygomatic craniotomy is performed. The dura is elevated from the cavernous sinus (CS). The anterior temporal fossa floor is drilled. Foramen rotundum and ovale are opened. The PPF is exposed and the lateral margin of inferior orbital fissure (IOF) is removed. The anterolateral triangle (ALT) is drilled and the vidian nerve (VN) is exposed. Drilling between the maxillary nerve (V2) and the VN provides access to the sphenoid sinus (SphS). The medial pterygoid plate is drilled exposing the EP. The maxillary sinus (MaxS) is opened anterior to the PPF. V2 is transposed laterally to enlarge the anteriomedial triangle (AMT). The orbital muscle of Muller is removed as well as the medial margin of the IOF, which opens the SphS. Anteriorly, the posterior ethmoid air cells are opened. Morphometric measurements evaluating the size of the ALT were done and the PS, NC, EP were explored with the endoscope. RESULTS: The ALT and AMT triangle provides a wide exposure of the PPF, ITF, PPR. In addition, those triangles represent a deep entry point to explore the PS, NC, and EP. CONCLUSION: The ALT and AMT are useful corridors to access to the SphS, MaxS, PS, NC, and EP via a transcranial approach. The use of the endoscope through this corridor widely extend the extradural anterior temporal fossa approach which may be considered as a valuable alternative to the extended endoscopic endonasal approach for selected skull base lesions extending both intracranial and into the PS, NC and EP.

Anatomical localization of horizontal segment of the petrous internal carotid artery in transnasal endoscopic skull base surgery.

OBJECTIVE: To discuss the localization of horizontal segment of petrous internal carotid artery in transnasal endoscopic skull base surgery, and to provide anatomical data for clinical surgery. METHODS: The horizontal segment of the petrous internal carotid artery of 5 adult cadaveric heads were exposed by endoscopic transnasal and microscopic open approaches respectively, and the relevant data and images were measured and collected. RESULTS: The medial wall of the foramen spinosum is the lateral wall of the isthmus of the eustachian tube, and the thickness of the bone is 0.5 ± 0.2 mm. The medial wall of the isthmus of the eustachian tube is the lateral wall of the posterior genu of the carotid canal and the thickness of the bone is 0.2 ± 0.1 mm. The vidian nerve originates from the anterior genu of the petrous internal carotid artery. The distance from the base of vidian nerve to the isthmus of eustachian tube is 19.2 ± 2.8 mm. CONCLUSION: The foramen spinosum is the landmark of isthmus of the Eustachian tube. The isthmus of the Eustachian tube is the landmark of the posterior genu of the internal carotid artery. The line between the base of the vidian nerve and the isthmus of the Eustachian tube ioks the landmark of horizontal segment of the petrous internal carotid artery.

Morphometric assessment of important landmarks on skull intended for Vidian nerve surgery.

PURPOSE: The aim of our study was to determine guide parameters for clinicians by morphometric assessment of important landmarks on cranium intended for Vidian nerve surgery. METHODS: For the study, 23 half-skull bases, 40 skull bases and 40 skulls were obtained from the Department of Anatomy, Ege University Medicine Faculty. The vertical distances were measured using a digital caliper to the nearest 0.01 mm. RESULTS: The anterior opening of the Vidian canal (pterygoid canal) was observed as oval shaped on 57 specimens (31.1%), funnel shaped on 58 specimens (31.7%), round shaped on 64 specimens (35%) and septated on 4 specimens (2.2%). Vidian canal was embedded into the body of sphenoid on 55 specimens (52.4%) (embedded type) and protruded to sphenoidal sinus on 50 specimens (47.6%) (protruded type). 21 specimens of 50 were partial and 29 specimens were total. There were dehiscences on 21 specimens of 50 protruded type on the base of sphenoidal sinus (20%). Anterior opening of the Vidian canal was assessed according to medial lamina of pterygoid process. It was located medially in 169 of the specimens (92.3%) and laterally in 14 specimens (7.7%). CONCLUSION: Vidian canal and Vidian nerve are deeply located structures on skull. Vidian canal and surrounding structures are important landmarks for microsurgery and endoscopic approaches to Vidian nerve. We consider that knowledge of anatomical features of Vidian canal and preoperative imaging by CT (computed tomography) will be supportive when choosing and planning a safe surgical approach.

Relation between volume of sphenoid sinuses and protrusion of Vidian nerve: possible applications to Vidian neurectomy.

PURPOSE: Vidian neurectomy is a surgical procedure applied to different pathological conditions, including chronic rhinitis and sphenopalatine neuralgia. The choice of the correct surgical approach depends upon the possible protrusion of Vidian nerve into the sphenoid sinuses. The present study analyzes the possible relationship between protrusion of Vidian nerve and volume of sphenoid sinuses. METHODS: In total, 320 maxillofacial CT-scans were retrospectively assessed. Subjects equally divided among males and females (age range 18-94 years) were divided into three groups according to the profile of Vidian nerve protrusion: type 1: Vidian nerve inside the sphenoid corpus; type 2: partially protruding into the sphenoid sinus; and type 3: entirely protruding into the sphenoid sinus through a stalk. Volume of sphenoid sinuses was extracted through the ITK-SNAP-free software and automatically calculated. Possible statistically significant differences in prevalence of the three types between males and females were assessed through Chi-squared test (p < 0.05). Differences in volume of sphenoid sinuses in subjects included within the three types were assessed through one-way ANOVA test (p < 0.05), separately for males and females. RESULTS: Type 2 was the most prevalent (46.5%), followed by type 1 (38.8%) and type 3 (14.7%), without significant differences according to sex (p > 0.05). Volume significantly increased passing from type 1 to type 3 both in males (p < 0.01) and in females (p < 0.01). CONCLUSIONS: The results prove the existence of a strict relationship between sphenoid sinuses pneumatization and protrusion of the Vidian canal and give a contribution to the knowledge of this important anatomical variant in endoscopic surgery.

Morphometric analysis of vidian canal and its relations with surrounding anatomic structures by using cone-beam computed tomography.

BACKGROUND: We identified the vidian canal (VC) in a Turkish subpopulation on cone-beam computed tomography (CBCT) images and explored its anatomic relationships; the canal serves as an anatomic pathway during endonasal surgical approaches. MATERIALS AND METHODS: Coronal and axial CBCT images of 100 patients (50 males and 50 females) were evaluated (slice thickness and interval, 0.5 mm). We measured the length of the VC length, extent of VC pneumatisation into the sphenoid sinus, position of the VC relative to the medial pterygopalatine plate (MPP), pterygopalatine fossa (PPF) depth, and VC-VC, VC-MPP, and VC-foramen rotundum (FR) distances, the angle between the posterior end of the middle turbinate and the lateral part of the VC anterior opening, and the angle between the VC and the palatovaginal canal. RESULTS: The mean VC length was 13.09 ± 2.07 and 13.01 ± 2.12 mm on the right and left sides, respectively. Relative to the MPP, the VC was located medially in 54.5% of patients, on the same level in 36%, and laterally in 9.5%. Pneumatisation was of grade I in 24% of patients, grade II in 33%, grade III in 23.5%, and grade IV in 19.5%. The VC-FR and VC-MPP distances were significantly greater on the left side. The angle between the posterior end of the middle turbinate and the lateral part of the anterior VC opening was significantly greater on the right side. The VC-VC distance was significantly greater when the VC lay lateral to the MPP. CONCLUSIONS: Anatomic characteristics of the VC on CBCT images unique to Turkish populations should be kept in mind during surgery.

Endoscopic prelacrimal approach to lateral recess of sphenoid sinus: feasibility study.

BACKGROUND: Various pathologies, including cerebrospinal fluid leaks and meningoencephaloceles, may arise in the lateral recess of the sphenoid sinus (LRSS), which may be accessed via an endonasal transpterygoid approach. The objective of this study was to evaluate the feasibility of accessing the LRSS via an endoscopic prelacrimal approach. Furthermore, we hypothesized that this approach may protect the pterygopalatine ganglion and vidian nerve. METHODS: Five cadaveric heads (9 sides) with a well-pneumatized LRSS were identified and an endonasal prelacrimal approach was performed. The infraorbital nerve, at the orbital floor, served as a critical landmark. After identification of the foramen rotundum at the pterygoid base, the vascular compartment of the pterygopalatine fossa and the pterygopalatine ganglion were displaced inferomedially and superomedially, respectively. Drilling of the bone inferomedial to the foramen rotundum allowed entry into the LRSS. RESULTS: The average distances from the prelacrimal window to the pterygoid base and the posterior wall of the LRSS were 6.22 ± 0.39 cm and 7.16 ± 0.50 cm, respectively. The average areas of the bony prelacrimal window and pterygoid base window were 4.33 ± 0.32 cm2 and 0.73 ± 0.10 cm2 , respectively. The LRSS could be accessed using a 0-degree endoscope, and pterygopalatine neurovascular structures, including the pterygopalatine ganglion and vidian nerve, could be preserved on all 9 sides. CONCLUSION: Our findings suggest that an endonasal prelacrimal approach provides a reasonable alternative to access the LRSS while preserving the vidian nerve and pterygopalatine ganglion.

Anatomical variation of the sphenoid sinus in paediatric patients and its association with age and chronic rhinosinusitis.

OBJECTIVE: To report the prevalence of different anatomical variations of the sphenoid sinus and its related structures among paediatric patients with or without chronic rhinosinusitis. METHODS: Computed tomography scans of 50 paediatric patients with chronic rhinosinusitis were reviewed and compared to 50 scans of paediatric patients without chronic rhinosinusitis. The type of sphenoid sinus pneumatisation and the surrounding structures were thoroughly analysed. The patients were divided into three groups according to age. RESULTS: Mean age was 10.9 years (range, 4-16 years). The sellar configuration was the commonest in all groups, while the conchal type was the least common. There were significant differences between paediatric patients with or without sinusitis in: sphenoid sinus pneumatisation type, vidian canal type and Onodi cell presence. In addition, there were significant differences between age groups in: sphenoid sinus pneumatisation type, single sinus septum and multiple septa presence, and internal carotid artery bulging. CONCLUSION: Age and sinusitis have a significant impact on sphenoid pneumatisation type and surrounding structure variation. Recognition of these variations can be useful for mapping this region, and enables a safer and more efficient endoscopic surgical procedure.

Lateral Transorbital Versus Endonasal Transpterygoid Approach to the Lateral Recess of the Sphenoid Sinus-A Comparative Anatomic Study.

BACKGROUND: The treatment of cerebrospinal fluid leaks of the lateral recess of the sphenoid sinus (LRSS) faces difficulties due to the deep location of the osseous defect. When treated with craniotomies, brain retraction is a concern. The endoscopic endonasal transpterygoid approach (EETA) is a direct and less invasive procedure; however, it may require transection of the vidian nerve (VN). OBJECTIVE: To investigate the feasibility of a lateral transorbital approach (LTOA) as an alternative pathway to the LRSS that avoids VN sacrifice. METHODS: Six embalmed heads with well-pneumatized LRSS were preselected by inspecting their computed tomography scans. One LTOA and one EETA were performed on 1 side of each specimen. The approaches were compared regarding working distance and neurovascular structures being sacrificed. The working area of the LTOA was also measured. RESULTS: The average working distances were 59.9 (±2.94) mm for the LTOA and 76.4 (±3.99) mm for the EETA (P < .001). The LTOA generated a working area with a diameter of 9 to 14 mm. The EETA demanded the sacrifice of VN and the sphenopalatine artery in all specimens to expose the LRSS. No neurovascular structures were found in the trajectory of the LTOA. CONCLUSION: The LTOA to the LRSS is feasible, with minimal risk of injuring neurovascular structures. It offers a shorter pathway when compared to the EETA. Although the LTOA provides no options for vascularized flap reconstruction, it allows immediate access to muscle grafts. The LTOA may serve as an alternative to treating cerebrospinal fluid leaks of the LRSS.