Superior Orbital Fissure Research Articles

Quantitative Anatomic Comparison of Microsurgical Transcranial, Endoscopic Endonasal, and Transorbital Approaches to the Spheno-Orbital Region.

The spheno-orbital region (SOR) is a complex anatomic area that can be accessed with different surgical approaches. To quantitatively compare, in a preclinical setting, microsurgical transcranial approaches (MTAs), endoscopic endonasal transpterygoid approach (EEA), and endoscopic transorbital approaches (ETOAs) to the SOR. These approaches were performed in 5 specimens: EEA, ETOAs (superior eyelid and inferolateral), anterolateral MTAs (supraorbital, minipterional, pterional, pterional-transzygomatic, and frontotemporal-orbitozygomatic), and lateral MTAs (subtemporal and subtemporal transzygomatic). All specimens underwent high-resolution computed tomography; an optic neuronavigation system with dedicated software was used to quantify working volume and exposed area for each approach. Mixed linear models with random intercepts were used for statistical analyses. Anterolateral MTAs offer a direct route to the greater wings (GWs) and lesser wings (LWs); only they guarantee exposure of the anterior clinoid. Lateral MTAs provide access to a large area corresponding to the GW, up to the superior orbital fissure (SOF) anteriorly and the foramen rotundum medially. ETOAs also access the GW, close to the lateral portion of SOF, but with a different angle of view as compared to lateral MTAs. Access to deep and medial structures, such as the lamina papyracea and the medial SOF, is offered only by EEA, which exposes the LW and GW only to a limited extent. This is the first study that offers a quantitative comparison of the most used approaches to SOR. A detailed knowledge of their advantages and limitations is paramount to choose the ideal one, or their combination, in the clinical setting.

Microsurgical Resection of Hybrid Nerve Sheath Tumor Involving the Orbit and Lateral Wall of the Cavernous Sinus: 2-Dimensional Operative Video.

Surgical removal of the tumor involving both the orbital and cavernous sinus remains challenging. Hybrid nerve sheath tumors (HNSTs) are defined as benign peripheral nerve sheath tumors with combined features of more than one type of benign peripheral nerve sheath tumors, including schwannoma, neurofibroma, and perineurinoma.1 They rarely arise from the orbit.1-3 This video shows the microsurgical resection of HNST involving both the orbit and lateral wall of the cavernous sinus. A 43-yr-old woman presented with 1-yr history of a slowly growing painless mass in her left medial eyelid. Neuroimaging examinations demonstrated a multilobulated and well-demarcated mass with a heterogeneous enhancement located in the extraconal region, just above the levator muscle, and extending from the eyelid to the middle fossa through the superior orbital fissure. Based on the neuroimaging features, we diagnosed it as trigeminal schwannoma involving the orbit and lateral wall of the cavernous sinus preoperatively. We performed left frontotemporal craniotomy with superolateral orbitotomy to gain access to the tumor. The tumor was grayish yellow and relatively firm. No intact nerve fibers of the frontal and ophthalmic nerves could be identified, making the diagnosis of the tumor originating from both nerves. Finally, we completely resected the tumor, which was confirmed by postoperative magnetic resonance images. Her postoperative course was uneventful, except for transient diplopia and expected left forehead hypesthesia. The pathology returned to HNST containing schwannoma and neurofibroma with no malignancy. The patient consented to the procedure prior to the surgery. And, the patient consented to the publication of their image.

Evaluating Morphology of the Pterygomaxillary Junction and Its Association With the Orbit in Different Facial Skeletal Relationships

The etiology for blindness after Le Fort I osteotomy is poorly understood. The authors propose that a study of the morphology and anatomical relationship of the pterygomaxillary junction to orbital vital structures may be crucial for understanding the possible etiology. This retrospective observational study involved analysis of data procured from computed tomography scans of individuals who were categorized into 4 groups based on their skeletal characteristics: skeletal Class I, II, and III and cleft lip and palate (CLP). The outcome variables included i) the height, width, and thickness of the pterygomaxillary junction (PTMJ) which represent its morphology and ii) distance of the PTMJ to the superior orbital fissure and optic canal, to demonstrate its proximity to orbital vital structures. Primary outcome measures were to i)compare variance of the outcome variables across groups, ii) determine association between PTMJ morphology and its proximity to the orbit, and iii) determine association between skeletal morphology and the outcome variables. Data were analyzed using descriptive and inferential statistics to study variance and association. Forty patients (80 sides) were divided into 4 groups. The CLP group demonstrated maximum height and thickness of the PTMJ, whereas the Class II group demonstrated the minimum (P<.001 and P=.001, respectively). The CLP group demonstrated the closest proximity of the PTMJ to orbital vital structures (P<.001), with Class II being the farthest (P<.001). There was a weak positive correlation between the PTMJ height and its thickness and width, whereas a moderate negative correlation was seen between the PTMJ height and its distance from the optic canal and superior orbital fissures (P<.001). Morphology of the PTMJ varies with facial skeletal relationship and also influences the relationship of the PTMJ with the orbital vital structures. This may be critical in understanding the pathophysiology of blindness after Le Fort I osteotomies.

Simpson Grade I Resection of Type II Clinoidal Meningioma Through Cranio-orbital Zygomatic Approach: 2-Dimensional Operative Video.

Clinoidal meningiomas have been considered as a separate entity with distinguishing clinical, radiological, and surgical considerations.1-2 Surgical mortality and morbidity associated with anterior clinoidal meningiomas has remained high in the past, with radical resection considered unattainable.3 However, the extent of surgical removal is clearly the most determining factor in tumor recurrence and progression. Clinoidal meningiomas have been classified into 3 types according to their origin from the dura surface of the anterior clinoid and subsequent arachnoidal rearrangement around the parasellar neurovascular structures.1 In type II, there is an arachnoidal plane that allows the tumor dissection from the encased carotid artery and its branches and the optic nerve. In this type, the involvement of the cavernous sinus is limited to the external wall, which can also be removed. Hence, these tumors are amenable to Simpson grade I resection (tumor, dura, and bone). Approaching through the multidirectional axis provided by the cranio-orbital zygomatic approach allows safe exposure of the tumor and vascular control.4-5 Proximal carotid control is obtained in the petrous carotid canal, the invaded anterior clinoid is removed by and large extradurally, and the Sylvian fissure is split wide open to establish dissecting planes with the middle cerebral artery branches. The optic canal is opened, and tumor extension is removed.6 The invaded outer wall of the cavernous sinus and superior orbital fissure is removed. We demonstrate this technique in a 48-yr-old patient who consented for surgery and publication of images. All images at 2:27, center and right images at 2:46, and all images at 2:58, reused with permission from LWW, from Al-Mefty, Operative Atlas of Meningiomas. Left image at 2:46 reprinted from Surg Neurol, Vol 60/issue 6, Arnautović KI, Al-Mefty O, Angtuaco E, A combined microsurgical skull-base and endovascular approach to giant and large paraclinoid aneurysms, pp. 504-520, Copyright 1998, with permission from Elsevier. Image at 8:21 reprinted from Al-Mefty,1 Clinoidal meningiomas, by permission from JNSPG.

Tolosa-Hunt syndrome: A rare entity

Tolosa Hunt syndrome(THS) is an inflammatory process adjacent to the cavernous sinus or within the superior orbital fissure and/or orbital apex. It is a rare entity well-defined clinically but of unknown etiopathogenesis.

Recurrent alternating Tolosa-Hunt syndrome mimicking idiopathic hypertrophic pachymeningitis

Tolosa–Hunt syndrome (THS) is a granulomatous inflammation in cavernous sinus or orbital apex. Recurrences are encountered ipsilaterally. Contralateral involvement is known as alternating THS. A middle-aged man presented with right sided headache and vomiting. Magnetic resonance imaging (MRI) revealed hyperintense lesion in right orbital apex with inflammatory changes in superior orbital fissure. A diagnosis of idiopathic hypertrophic pachymeningitis (IHP) was entertained. Within 48 h, there was complete ptosis and markedly restricted ocular movements. MRI done 3 months prior revealed similar features in left eye. A rare case of recurrent alternating THS with radiological evidence is portrayed here.

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Recurrent Tolosa-Hunt Syndrome in a Child Accompanied by Idiopathic Aseptic Meningitis

Tolosa-Hunt syndrome (THS) is an idiopathic sterile granulomatous inflammation of the cavernous sinus, characterized by painful ophthalmoplegia.1 Magnetic resonance imaging (MRI)–proven or biopsy-proven granulomatous inflammation of the cavernous sinus, superior orbital fissure, or orbit is required for the diagnosis of THS according to the International Classification of Headache Disorders (ICHD) criteria.1 Although corticosteroids are highly effective,2 THS often recurs and no standard corticosteroid dose has been defined.

The use of mnemonics for better academic performance of medical university students in the study of anatomical terms

Annotation. Mnemonics are a combination of special methods and techniques that make it easier to memorize the necessary information and increase the amount of memory by forming associations. The aim of the work is to develop techniques that will help medical students effectively learn anatomical terms by facilitating the memorization of large amounts of information. In this article, we used the following mnemonic techniques: first letter mnemonics or acronyms and the "Comparison" method - to identify common features in the studied and well-known material, namely the similarity in form. This article includes mnemonics that will help to easily learn the following terms namely the anatomy of the skeleton bones for memorizing the bones of the medial wall of the orbit, the bones in the nasal septum, the wrist bones, the ankle tarsal bones, recognition of thoracic vertebrae from the lumbar, cranial bones, upper limb bones, bones of the lower limb, the vertebral regions, the hand, the arm bones and the bone projections. Also included are mnemonics on the anatomy of the cranial nerves that pass through the superior orbital fissure and branches of the facial nerve, mnemonics on the anatomy of the peripheral nervous system, namely somatic nerve plexuses, which include the brachial plexus branches. Also included are mnemonics on the anatomy of the upper limbs muscles, namely the muscles that form the rotator cuff in the shoulder, muscles involved in elbow flexion and the anterior flexor muscles of the forearm and mnemonics on the anatomy of the trunk muscles, namely the paired erector spinae muscles and abdominal muscles. Finally, this article includes a mnemonic on the anatomy of the male reproductive system, namely the layers of the scrotum. In the future, new mnemonics will be developed that relate to splanchnology, anatomy of the central nervous system, anatomy of the sensory organs and anatomy of the cardiovascular system, which were not listed above.

AB0853 IGG4-RELATED DISEASE CAUSING OCULAR NERVE PALSIES AND ORBITAL APEX SYNDROME: CASE REPORT AND LITERATURE REVIEW

Background:IgG4-Related Disease (IgG4-RD) is a systemic immune-mediated fibroinflammatory condition. The epidemiology is not well defined: it usually affects adults from middle-age onwards, predominantly male. Both B and T-cells are central in IgG4-RD pathogenesis, as demonstrated by the efficacy of B-cell depletion therapy.IgG4-RD can affect multiple organs including the central and peripheral nervous system, producing a constellation of clinical symptoms and signs, depending on the organ structures involved.IgG4-related orbital disease is relatively rare can implicate all extra-ocular muscles, structures emerging from the Orbital apex, optic canal, or superior and inferior orbital fissure. Depending on the structures involved, it can produce different or sometimes subtle clinical presentations, posing diagnostic challenge. There were case reports of IgG4-related ophthalmic disease misdiagnosed as intraocular tumour.Objectives:IgG4-RD is increasingly recognised as an entity affecting the head and neck region. However, it rarely involves skull base and presents with orbital apex syndrome. In this current case report, we describe an interesting case of IgG-related orbital disease presenting with ocular nerve palsies and orbital apex syndrome.Methods:Case report.Results:A 36-year-old gentleman with cocaine and alcohol misuse presented with a 2-month history of left sided headache, diplopia, recurrent ear infections, otalgia and hearing loss. Initial imaging suggested left otomastoiditis and intravenous antibiotics were commenced. Contralateral partial third nerve palsy with pupil sparing was elicited. 2 months later, there was worsening right eye ptosis, proptosis, right relative afferent pupillary defect, reduced visual acuity and colour vision as well as a near-complete ophthalmoplegia. Subsequent imaging showed worsening soft tissue swelling centred on the upper left parapharyngeal and masticator space, with multiple perineural enhancement and lateral extension to right orbital apex and orbital fissures. Blood tests only revealed raised IgG4 subclass. Infectious aetiology was excluded. Left nasal mass biopsy performed showed no fungal organism or malignancy. There were lymphoplasmacytic proliferation but no storiform fibrosis or obliterative phlebitis. IgG4 immunostaining on two assessable fields revealed 22 and 17 positive plasma cells respectively, and an IgG4: IgG ratio of &lt;10%, and 50% in the other. Significant improvement was seen clinically and radiologically with antibiotics and a tapering regime of oral Prednisolone. Patient was commenced on Azathioprine as long term immunosuppression.Conclusion:A high degree of clinical suspicion is necessary to diagnose IgG4-RD when presenting with orbital apex syndrome and ocular nerve palsies,IgG4-RD can mimic mastoiditis of infectious aetiology. Other differentials may include cocaine-induced midline destructive lesions and granulomatosis with polyangiitis. The diagnosis can be supported by elevated serum IgG, elevated IgG index and pathognomonic histopathological findings. . The diagnosis of IgG4-related orbital disease should be deliberated on by a multidisciplinary group, with every effort being made to exclude an infectious aetiology, before embarking on immunosuppressive therapy.Primary treatment is with steroids. However, immunotherapy using azathioprine can be utilised in recurrent disease or patients with steroid intolerance.

Clinoidal Meningioma with Cavernous Sinus Invasion.

We present a-49-year old female presenting headache and progressive right eye visual loss in the last 6 months. Magnetic resonance imaging showed a large clinoidal meningioma on the right side, invading the superior, lateral and medial aspects of the cavernous sinus, the optic canal, and the clinoidal segment of the internal carotid artery (ICA).A cranio-orbital approach was performed. The anterior clinoid process was removed extradurally to achieve devascularization of the anterior clinoidal meningioma, followed by the peeling of the middle fossa to decompress V2 and open the superior orbital fissure. We open the dura in a standard fronto-temporal flap to access the lower portion of the skull base allowing retractorless dissection. We complete the removal of the anterior clinoid process and optic strut through an intradural approach. It allows safer dissection of the clinoidal segment of the ICA and avoids its injury by adherent and hard consistency tumor.Intraoperative neurophysiological monitoring, sharp dissection, and avoiding the use of bipolar coagulation when dissecting the cavernous sinus are essential to minimize the risk of cranial nerve injury. We also like to point that cranial nerve deficit caused by surgical manipulation without primary lesion of the nerve can be recovered postoperatively. The link to the video can be found at: https://youtu.be/ozUCsnUGxyM .

Endoscopic-Assisted Microsurgical Resection of Right Recurrent Meckel's Cave Meningioma Extended to Cavernous Sinus.

Objective This study was aimed to present the complete removal of a large recurrent Meckel's cave meningioma. Design This study is a case report. Setting The study was conducted at Department of Neurosurgery and Skull Base Laboratory at Lariboisiére Hospital, Paris. Participant A 53-year-old male was presented with a severe V1, V2, and V3 hypoesthesia and pain. He was operated 7 years ago for a right Meckel's cave meningioma with postoperative V1–V2 hypoesthesia. Magnetic resonance imaging (MRI) showed a large tumor recurrence extending into the cavernous sinus (CS), posterior fossa (PF), sphenoid sinus (SS), pterygopalatine (PPF), and infratemporal fossa (ITF; Fig. 1 ). Main Outcome Measures Radiological results and postoperative course were assessed for this study. Results The previous right frontotemporal approach was used. The lateral wall of the orbit, the middle fossa floor and the anterior temporal base were drilled to expose the orbit, PPF, and ITF. Foramen ovale (FO), foramen rotondum (FR), and superior orbital fissure (SOF) were opened. The meningoorbital band was cut and the lateral wall of CS was elevated ( Fig. 2 ). The inferior orbital fissure was opened and tumor removed into the ITF, PPF, and orbit. After entering Meckel's cave from above, tumor was removed from PF. After microsurgical tumor removal, a 45-degree endoscope was used to remove tumor remnant and mucosa into SS. A watertight dural closure with pericranium was performed, reinforced with autologous fat and fibrin glue. Postoperative MRI showed complete tumor resection ( Fig. 1 ). The patient experienced a right-side keratitis that resolved within 10 days and a V3 hypoesthesia that improved at 2 months. Conclusion This surgical case shows how the anatomical knowledge is mandatory in skull base surgery and how the integration of microsurgical and endoscopic-assisted techniques allows to obtain optimal results. The link to the video can be found at: https://youtu.be/qxt_389AdWU .

Endoscopic Transnasal Resection of Trigeminal Schwannoma.

Trigeminal schwannoma is a rare skull base tumor that can be managed in a variety of treatments including image observation, surgery, stereotactic radiosurgery, such as gamma knife radiosurgery (GKS), and combination of these. Endoscopic transnasal resection is very effective when the tumor is not invading far laterally, or the risk of cerebrospinal fluid (CSF) leak is estimated to be low. A 74-year-old man with a history of prostate cancer and diabetes presented with left oculomotor nerve palsy over a month. Magnetic resonance images (MRI) demonstrated a 25-mm mass in the left cavernous sinus protruding to the left orbit via the superior orbital fissure ( Fig. 1 ). The patient underwent endoscopic transnasal surgery to decompress the mass. The surgery was uneventful, and postoperative MRI demonstrated satisfactory subtotal resection of the mass ( Fig. 2 ). The final pathology returned as schwannoma. At 1-year follow-up, the tumor slowly enlarged, and the patient underwent GKS with a marginal dose of 14 Gy. At the last follow-up, 4 months after GKS, the tumor was stable. Unfortunately the patient deceased from the known prostate cancer. Endoscopic transnasal surgery was especially useful in this case, considering the preoperative known cancer state that management of this benign tumor did not ruin the quality of life of this patient while minimizing hospitalization, as achieving satisfactory tumor control with aid from postoperative GKS, minimizing complications. The link to the video can be found at: https://youtu.be/Q0Ugc2VFV4w .

Spheno-Orbital Meningioma with Cavernous Sinus Extension.

We present a case of a 37-year-old female, with progressive left eye proptosis and an extensive ipsilateral en plaque spheno-orbital meningioma, with diffuse involvement of the lateral wall of the cavernous sinus and the orbit.A cranio-orbital zygomatic approach was performed to reach all extension of the lesion. We made an extradural clinoidectomy and an extensive bone removal of the orbit, exposition of the superior and lateral walls of the cavernous sinus, unroofing of the optic canal, superior orbital fissure, foramen rotundum, and foramen ovale. We performed the peeling of the lateral wall of cavernous sinus with total removal and preservation of the cranial nerves anatomy and function.In this video, we illustrate the importance of the first time aggressive removal of such tumors. We also demonstrate the concept that secondary invasion of the cavernous sinus are suitable for removal with cranial nerve preservation. The link to the video can be found at https://youtu.be/GJmkqVa6jSs .

Pretemporal Transcavernous Approach for Resection of an Orbito-Cavernous Oculomotor Schwannoma.

The following operative video demonstrates surgical tenets and nuances of the pretemporal transcavernous approach in an unusual case of a 33-year-old patient suffering new onset diplopia and a third nerve palsy due to an orbito-cavernous oculomotor schwannoma. Near total resection was accomplished through an extended pterional craniotomy with pretemporal transcavernous exposure of her lesion, resulting in resolution of her preoperative oculomotor palsy and visual dysfunction. When combined with extended pterional and modified frontotemporal orbitozygomatic approaches, the pretemporal transcavernous approach provides excellent surgical access to the parasellar region including the superior orbital fissure and cavernous sinus. Meticulous dissection and early identification of tissue planes, including cranial nerve and vascular anatomy, allows for safe removal of tumors arising in this region. The link to the video can be found at: https://youtu.be/EuIRTP7wWBQ .

A Rare Case of Sphenoid Sinus Mucocele Presenting with Lateral Rectus Palsy.

The sphenoid sinus mucoceles are rare and have an incidence of 1%, when sufficiently large they can compress optic canal, superior orbital fissure and vital structures causing optic neuropathy, ptosis, ophthalmoplegia and diplopia. We herein report a 73year old male who presented with headache and left lateral rectus palsy secondary to sphenoid sinus mucocele which was confirmed on MRI and successfully treated with endoscopic marsupialization.

Pseudo orbital apex disorders

Multiple cranial nerve palsies are clinical conundrums that can be solved by determining zones of the proximity of the affected nerves. The affliction of two or more contiguous neuroanatomic structures helps in the localization of the causative lesion. However, there are certain caveats to this method of estimation when it may not be applicable such as in cases of multifocal or diffuse pathologies and large mass lesions. Orbital apex disorders refer to the clinical spectrum arising from lesions in the orbital apex, superior orbital fissure, and cavernous sinus. Besides, large neoplasms in the middle cranial fossa too may have a similar presentation. It is essential to consider the possibility of false localizing signs, as is highlighted in our two case reports, both of which initially appeared to be caused by orbital apex region lesions.

Cranio-Orbital Pretemporal Approach for Resection of Right Superior Orbital Fissure/Orbital Renal Cell Metastasis: 2-Dimensional Operative Video.

Orbital metastatic lesions are rare entities1-3 best treated with radical surgical resection with preservation/improvement of neurological and visual function.1-9 Renal cell metastases, in particular, respond less favorably to radiation.9 To our knowledge, an operative video of microsurgical resection of a renal cell carcinoma metastasis to the superior orbital fissure and orbit has not been reported.A patient presented with worsening right eye vision as demonstrated on preoperative visual field testing and found to have a 3 × 1 × 1 cm lesion in the orbit and superior orbital fissure. The patient was placed supine and stealth neuronavigation was used to aid in tumor localization and extension. A cranio-orbital craniotomy and pretemporal exposure2,10,11 were performed to allow extradural dissection of the dura propria off the lateral wall of the cavernous sinus. Right-sided extradural cranial nerves II, III, IV, V1, and V2 were identified, and a high-speed diamond drill was used to perform extradural anterior clinoidectomy and optic nerve decompression. Microsurgical resection of the intraorbital tumor components was performed by the senior author (KIA) to delineate the plane between tumor and periorbita. An oval-shaped dural opening was made to resect the dura involved by tumor, confirmed on histological analysis, followed by closure via dural allograft. The patient's right-sided visual field improved markedly after surgery.Metastatic renal cell carcinoma of the orbit should be resected while preserving and improving preoperative neurological and visual function. The orbitocranial pretemporal approach offers wide visualization to achieve surgical resection.The patient provided written consent and permission to publish her image.

Microsurgical management in Anterior Communicating Artery Aneurysms: an anatomical investigation

Purpose: The purpose of this study is to compare the pterional approach and the anterior interhemispheric approach for enabling a better surgical maneuverability. We describe the ideal the anatomic limitations of this surgery for anterior communicating artery aneurysms. Methods: 4 formalin-fixed and silicone injected human heads were used for each approach. Möller 20-1000 microscope was used for dissection and all the photographs were obtained at a similar angle to the surgical microscope, with Canon EOS Rebel T5 Digital SLR Digital Camera with a EF 100mm f/2.8L Macro IS USM Lens and a Canon MR-14EX II Macro Ring Lite Flash. Our dissection includes anterior interhemispheric and pterional approach with gyrus rectus resection and posterolateral orbitotomy. Results: Pterional approach was performed followed by the gyrus rectus resection and posterolateral orbitotomy. This area can be exposed by the 1x1 cm resection of the gyrus rectus. Subpial resection from posterior part of gyrus rectus is required. Posterolateral orbitotomy was performed and the orbital roof was removed up to the superior orbital fissure. The anterior interhemispheric approach allows better visualization of the anterior and inferior surface of anterior communicating artery, A1-A2 junction and the optic nerve. Conclusions: We believe the pterional approach combined with gyrus rectus resection and posterolateral orbitotomy, if needed, is more suitable for anterior, posterior and inferior type, with anterior interhemispheric approach being the safer for superior and high positioned anterior communicating artery aneurysms.

The Ophthalmopetrosal Sinus of Hyrtl: The Evidence of A Rare Variant.

Hyrtl [Wien Med Wochenschr. 1862;19:291-292] reported firstly the ophtalmopetrosal sinus (OPS) running from the superior orbital fissure and emptying either in the transverse sinus, or in its junction with the superior petrosal sinus. Since then, this anatomic variant was mostly referred and poorly studied. Neither Hyrtl, nor other authors brought any evidence of such OPS. It is hereby reported and proofed such an OPT which was found at dissection. It drained ophthalmic veins and coursed posteriorly, first on the greater wing (alar segment), then on the temporal bone (temporal segment, on the petrosquamous fissure), emptying in the transverse sinus. A lateral type of the superior petrosal sinus connected the OPS and the transverse sinus. The OPS courses on the middle fossa floor, lateral to the Meckel's cavum, foramen ovale, foramen spinosum, and fallopian hiatus. It is a rare thus unexpected finding during specific approaches of the middle fossa floor.