Lateral Cavernous Sinus Research Articles

Carotid Plexus Sympathetic Nerves as a Landmark for the Abducens Nerve Within the Cavernous Sinus During Endoscopic Endonasal Surgery: Cadaveric Anatomic Study and Surgical Consideration.

The abducens nerve (CN VI) is vulnerable to injury during endoscopic endonasal transcavernous surgery. In this study, the authors aimed to develop the surgical anatomic landmark and explore the relationship between the sympathetic nerves (SNs) around the internal carotid artery (ICA) and CN VI within the cavernous sinus (CS). The relationship and patterns between the SNs and CN VI were investigated in 15 cadaveric specimens. The intraoperative examples of anatomic landmark were presented. There were SNs around the ICA running into the CN VI, classified into ascending SNs and accessory sympathetic branches. The ascending SNs were divided into 3 types: (1) Type I had a single ascending SN. There were 2 subtypes of Type I (Type IA [17/30, 56.7%] was defined as a single ascending branch that ran into the CN VI, and Type IB [4/30, 13.3%] was defined as a single ascending branch with a terminal bifurcation before merging into the CN VI or lateral CS wall), (2) Type II (7/30, 23.3%) was defined as 2 ascending branches that ran into the CN VI and the lateral CS wall, and (3) Type III (2/30, 6.7%) was defined as 3 ascending branches that ran into the CN VIs and the lateral wall of the CS. The accessory branches of the SNs were defined by sympathetic branches from the posterior genu or horizontal ICA and found in 6/30 sides (20%). The authors propose a classification of the relationship between paraclival ICA SNs and the CN VI within the CS, as approached during endoscopic endonasal surgery. The consistent relationship of the ascending SN and CN VI within the CS provides a reliable anatomic landmark during the endonasal approach to the CS.

Transorbital approach to the cavernous sinus: an anatomical study of the related cranial nerves.

The cavernous sinus (CS) is a demanding surgical territory, given its deep location and the involvement of multiple neurovascular structures. Subjected to recurrent discussion on the optimal surgical access, the endoscopic transorbital approach has been recently proposed as a feasible route for selected lesions in the lateral CS. Still, for this technique to safely evolve and consolidate, a comprehensive anatomical description of involved cranial nerves, dural ligaments, and arterial relations is needed. Detailed anatomical description of the CS, the course of III, IV, VI, and V cranial nerves, and C3-C7 segments of the carotid artery, all described from the ventrolateral endoscopic transorbital perspective. Five embalmed human cadaveric heads (10 sides) were dissected. An endoscopic transorbital approach with lateral orbital rim removal, anterior clinoidectomy, and petrosectomy was performed. The course of the upper cranial nerves was followed from their apparent origin in the brainstem, through the middle fossa or cavernous sinus, and up to their entrance to the orbit. Neuronavigation was used to follow the course of the nerves and to measure their length of surgical exposure. The transorbital approach allowed us to visualize the lateral wall of the CS, with cranial nerves III, IV, V1-3, and VI. Anterior clinoidectomy and opening of the frontal dura and the oculomotor triangle revealed the complete course of the III nerve, an average of 37 (±2) mm in length. Opening the trigeminal pore and cutting the tentorium permitted to follow the IV nerve from its course around the cerebral peduncle up to the orbit, an average of 54 (±4) mm. Opening the infratrochlear triangle revealed the VI nerve intracavernously and under Gruber's ligament, and the extended petrosectomy allowed us to see its cisternal portion (27 ± 6 mm). The trigeminal root was completely visible and so were its three branches (46 ± 2, 34 ± 3, and 31 ± 1 mm, respectively). Comprehensive anatomic knowledge and extensive surgical expertise are required when addressing the CS. The transorbital corridor exposes most of the cisternal and the complete cavernous course of involved cranial nerves. This anatomical article helps understanding relations of neural, vascular, and dural structures involved in the CS approach, essential to culminating the learning process of transorbital surgery.

Endoscopic Transorbital Surgery for Trigeminal Schwannoma: Introduction of a Novel Approach: 2-Dimensional Operative Video.

The major indications of endoscopic transorbital approach include spheno-orbital meningiomas, cavernous sinus lesions, and Meckel cave lesion such as trigeminal schwannomas. It can avoid excessive brain retraction and allows for a fast recovery to the normal daily living activity. To access the cavernous sinus, the sagittal crest and meningo-orbital band should be identified and cut. 1. Skin incision along the superior eyelid is performed. 2. Careful dissection of the soft tissue under the orbicularis is required not to injure the orbital septum. 3. After the lateral orbital rim is exposed, the periosteum and periorbita are elevated from the lateral orbital wall. 4. Drilling of the zygomatic bone within the orbit exposes the temporalis muscle first followed by the exposure of the temporal dura. It is essential to obtain adequate working room when the base of the greater sphenoidal wing is drilled. The sagittal crest should be removed, and the meningo-orbital band should be cut to expose the lateral cavernous sinus wall. For successful access through the orbit, endoscopic transorbital approach needs to minimize the retraction of the orbit. To achieve this goal, retraction of the orbit should be limited to a maximum of 10 minutes. This approach can be combined with lateral orbitotomy. It provides a wider working room and makes surgery easier to access the lateral temporal lobe.The patient consented to the procedure, and the participants and any identifiable individuals consented to publication of his/her image. Images at 1:29 reproduced from Corrivetti F, de Notaris M, Di Somma A, et al, "Sagittal crest": definition, stepwise dissection, and clinical implications from a transorbital perspective, Operative Neurosurgery, 22(5), p e206-e212, ©2022, by permission from the Congress of Neurological Surgeons. Video screen capture from The Neurosurgical Atlas at 1:06 used with permission from Aaron Cohen-Gadol; ©The Neurosurgical Atlas, all rights reserved.

Lateral Transorbital Endoscope-Assisted Approach to the Cavernous Sinus.

Surgical access to the cavernous sinus (CS) poses a unique challenge to the neurosurgeon given the concentration of delicate structures in the confines of a very small anatomic space. The lateral transorbital approach (LTOA) is a minimally invasive, keyhole approach that can provide direct access to the lateral CS. A retrospective review of CS lesions treated by a LTOA at a single institution was performed between 2020 and 2023. Patient indications, surgical outcomes, and complications are described. Six patients underwent a LTOA for a variety of pathologies including a dermoid cyst, schwannoma, prolactinoma, craniopharyngioma, and solitary fibrous tumor. The goals of surgery (ie, drainage of cyst, debulking, and pathological diagnosis) were achieved in all cases. The mean extent of resection was 64.6% (±34%). Half of the patients with preoperative cranial neuropathies (n = 4) improved postoperatively. There were no new permanent cranial neuropathies. One patient had a vascular injury repaired endovascularly with no neurological deficits. The LTOA provides a minimal access corridor to the lateral CS. Careful case selection and reasonable goals of surgery are critical to successful outcome.

Minimally Invasive Transnasal Approach to the Anteromedial Temporal Fossa and Lateral Sphenoid Using a Novel Landmark between Periorbita and Periosteum of the Pterygopalatine Fossa: A Cadaveric Study.

The anteromedial temporal region and the lateral wall of the sphenoid can be the site of an array of pathology including trigeminal schwannoma, encephalocele, cholesterol granuloma of the petrous apex, malignancy, infection, and sellar pathology extending to the lateral cavernous sinus. Approaches to this region are technically challenging and the existing approach requires sacrifice of all of the turbinates including the nasolacrimal duct, which can cause postoperative complications. We describe a novel anatomical landmark between the periorbita and the periosteum of the pterygopalatine fossa (which is located at the inferolateral periorbital periosteal line [ILPPL]). The posterior one-third of the incision line lies between the foramen rotundum and the superior orbital fissure, which is proximal to the maxillary strut. A 1.5-cm incision can divide the orbital and pterygoid contents and lead us to the posterior inferolateral orbital region, anteromedial temporal region, lateral wall of the sphenoid sinus, and lateral wall of the cavernous sinus. A combined multiangled approach to the ILPPL will enable us to preserve all of the turbinates and the septum, and the nasolacrimal duct, allowing for the preservation of the physiological function and pedicled flaps, such as the middle turbinate, inferior turbinate, and septal membrane flap. The ILPPL is a simple, effective, and novel landmark for the minimally invasive approach to the anteromedial temporal fossa.

Endoscopic transorbital approach for skull base lesions: a report of 16 clinical cases.

Due to the deep location, complex anatomy, and adjacent vital neurovascular structures, skull base surgery is challenging and requires specific approaches. The emerging endoscopic transorbital approach (eTOA) technique provides a new approach to the orbital content, spheno-orbital region, lateral cavernous sinus, and Meckel's cave. In this study, the clinical utility and effectiveness of the eTOA are reported. Sixteen cases who underwent the eTOA were included in the current study. The patients were divided into 3 groups according to tumor location: Group A (intraorbital, 6 cases), group B (spheno-orbital, 7 cases), and group C (cavernous sinus, and Meckel's cave, 3 cases). The clinical data and surgical results were analyzed. Eight meningiomas, 2 hemangiomas, 1 low-grade glioma, 1 instance of inflammatory hyperplasia tissue, 1 Langerhans cell histiocytosis, 1 epidermoid cyst, 1 trigeminal schwannoma, and 1 bone fibrosis hyperplasia were observed. The mean tumor diameter was 2.4cm. A single case in Group A and Group C underwent biopsy (12.5%), and 1 case of fibrous dysplasia in Group B underwent sufficient orbit decompression (6.25%). The remaining 13 cases underwent gross total tumor resection (81.25%). No cerebral-spinal fluid leak or infection occurred. And no cosmetic problems or significant complications were observed during the follow-up. As a minimally invasive technique, the eTOA has unique advantages for carefully selected skull base lesions because of its direct route, short working distance, and distinct attack angle.

Case Report: Transorbital Neuroendoscopic Surgery (TONES) for a Case of Cavernoma-Associated Epilepsy Within the Mesial Temporal Lobe

Transorbital Neuroendoscopic Surgery (TONES) is a technique that allows access to the intracranial compartment, including the anterior cranial fossa, middle fossa and lateral cavernous sinus in addition to the contents of the orbit. Different surgical approaches are used for mesial temporal lobe epilepsy generating lesions over time. In this manuscript, we aim to share a case of a temporal lobe cavernoma who presented with refractory seizure and managed surgically by TONES procedure.

Growth hormone secreting pituitary adenomas show distinct extrasellar extension patterns compared to nonfunctional pituitary adenomas.

Patterns of extension of pituitary adenomas (PA) may vary according to PA subtype. Understanding extrasellar extension patterns in growth hormone PAs (GHPA) vis-a-vis nonfunctional PAs (NFPAs) may provide insights into the biology of GHPA and future treatment avenues. Preoperative MR imaging (MRI) in 179 consecutive patients treated surgically for NFPA (n = 139) and GHPA (n = 40) were analyzed to determine patterns of extrasellar growth. Extension was divided into two principal directions: cranio-caudal (measured by infrasellar/suprasellar extension), and lateral cavernous sinus invasion (CSI) determined by Knosp grading score of 3-4. Suprasellar extension was defined as tumor extension superior to the tuberculum sellae- dorsum sellae line, and inferior extension as invasion through the sellar floor into the sphenoid sinus or clivus. Categorical analysis was performed using Fisher's exact test. GHPAs were overall more likely to remain purely intrasellar compared to NFPA (50% vs 26%, p < 0.001). GHPAs, however, were 7 times more likely to exhibit isolated infrasellar extension compared to NFPA (20% vs 2.8%, p = 0.001). Conversely, NFPAs were twice as likely to exhibit isolated suprasellar extension compared to GHPA (60% vs 28%, p < 0.001), as well as combined suprasellar/infrasellar extension (25% vs 3%, p = 0.011). There were no overall differences in CSI between the two subgroups. GHPA and NFPA demonstrate distinct extrasellar extension patterns on MRI. GHPAs show proclivity for inferior extension with bony invasion, whereas NFPAs are more likely to exhibit suprasellar extension through the diaphragmatic aperture. These distinctions may have implications into the biology and future treatment of PAs.

The Final Cut: Evolution of Cavernous Sinus Decompression Beyond the Dolenc Cut.

Meningiomas involving the cavernous sinus (CS) represent a formidable challenge to neurosurgeons. Because of high morbidity, aggressive tumor resection within the CS has been largely replaced by extracavernous tumor resection and decompression of the CS. The widely used Dolenc method involves blind dural transection over the oculomotor nerve, potentially placing the crossing trochlear nerve at risk. To provide a safer way for the decompression of the CS and at the same time, circumferential resection of the temporal lobe dura. Cadaveric dissection of 8 cadaveric heads (16 sides) was performed. Frontotemporal craniotomy with zygomatic osteotomy was performed. Extradural and intradural dissection of the lateral wall of the CS and free edge of tentorium was performed. Photographic documentation, artistic illustrations, and illustrative video cases are provided. Three tether points were released: anterior-the meningo-orbital band, lateral-dura over the V2 and V3, and medial-superficial layer of the free edge of tentorium. Transection of the superficial layer of the free edge of the tentorium along its edge, in conjunction with a lateral cut over the temporal convexity, constitutes the final cut, allowing a resection of the lateral CS wall and the circumferential resection of temporal lobe dura. Using the "final cut" technique allows for a circumferential resection of the temporal lobe dura and lateral CS wall while avoiding blind cuts that could put cranial nerves at risk. All dural transections are performed in anatomically separated layers under constant visualization.

Extradural Middle Fossa and Transcavernous Approach for Resection of Trigeminal Neurinoma at Lateral Cavernous Sinus.

We present a 52-year-old male case of right trigeminal neurinoma at lateral cavernous sinus. The tumor was 40 mm in maximum diameter, obviously compressed temporal lobe and encased internal carotid artery. Extradural middle fossa and transcavernous approach was applied and the tumor was resected via Parkinson's triangle. This approach enabled safe and effective tumor resection, sufficient visualization, and operative field ( Figs. 1 and 2 ). We performed dissection of the tumor from trigeminal nerve, tentorium, and middle fossa and resect the tumor around internal carotid artery sufficiently. Postoperative course was good without any new neurological deficit. This surgical method is considered safe and effective for the resection of the tumor at lateral cavernous sinus. The link to the video can be found at: https://youtu.be/2ekuILIgEuo.

Cavernous Sinus Meningioma: Tumor Decompression for Trigeminal Neuralgia and Anterior Tibial Artery Graft High-Flow Bypass for Brain Ischemia: 2-Dimensional Operative Video.

A 62-yr-old man with left cavernous sinus tumor presented with atypical trigeminal neuralgia refractory to medical treatment. He received Gamma Knife (Elekta) radiation for the tumor. However, the facial pain worsened after radiation. Neuropsychological testing done for memory problems had revealed mild neurocognitive disorder. Neurological examination showed trigeminal distribution numbness and partial abducens nerve paralysis. Imaging revealed an enhancing left cavernous sinus and supra-cavernous mass. Angiography revealed severe stenosis of the left cavernous internal carotid artery (ICA). Computed tomography (CT) perfusion study showed diminished blood flow on the left side, and ischemic changes were seen in fluid-attenuated inversion-recovery (FLAIR) magnetic resonance imaging (MRI). Surgical resection of the tumor was preferred over ablative treatment for trigeminal neuralgia because of its effectiveness in improving cranial nerve (CN) function.1 The patient underwent staged surgeries. In the first stage, the tumor was partially excised with decompression of the trigeminal ganglion and nerve root in the lateral cavernous sinus wall, Meckel's cave. Postoperatively, MR angiography revealed worsening of the left ICA caliber. Therefore, a high-flow bypass from the external carotid artery to the middle cerebral artery (MCA) was performed with an anterior tibial artery graft. The patient recovered initially but developed enterococcus meningitis postoperatively, which was promptly identified and treated with antibiotics. At 1-yr follow-up, the graft was patent, and the patient had significant relief of his facial pain and cognitively improved. This 2-dimensional video demonstrates the technique of partial excision of cavernous sinus meningioma with CN decompression, and the technique of a high-flow bypass from the external carotid artery to M2 MCA segment using an anterior tibial artery graft. The patient gave informed consent for surgery and video recording. All relevant patient identifiers have been removed from the video and accompanying radiology slides.

Recurrent Sphenocavernous Meningioma.

A case of a recurrent sphenocavernous meningioma is presented. The patient is a 42-year-old male who presented with an episode of transient right-sided numbness. A magnetic resonance imaging (MRI) revealed a large left sphenocavernous meningioma. The patient underwent a frontotemporal craniotomy for tumor resection. Near total resection was achieved with minimal residual in the left cavernous sinus (CS) and orbital apex. The pathology was consistent with meningioma, World Health Organization (WHO) grade I. A follow-up MRI was done 9 months after surgery and showed a growth of the residual tumor, which was treated with intensity modulated radiotherapy. Tumor growth was detected on serial imaging over a 4-year period. Surgical resection was offered. A left frontotemporal craniotomy with pretemporal transcavernous approach was performed. The bone flap was reopened and the dura was opened in a Y-shaped fashion. The roof of the optic canal was drilled off, and the falciform ligament was opened to decompress the optic nerve. The tumor was disconnected from the anterior clinoid region (the anterior clinoid process was eroded by the tumor) and reflected off the wall of the lateral CS. Tumor was adherent to the V2 fascicles (the lateral CS wall was resected in the first surgery) and was sharply dissected off. Gross total resection was achieved. The pathology was consistent with meningioma, WHO grade I. The patient had an unremarkable postoperative course without any new neurological deficits. The link to the video can be found at: https://youtu.be/KVBVw_86JqM .

Unilateral hydrocephalus from a gangliocytoma-somatotrophinoma: first reported case.

SummaryAlthough pituitary macroadenomas often cause mass effects on surrounding structures, it is extremely rare for pituitary lesions to disturb cerebrospinal fluid circulation. Sellar gangliocytoma-pituitary adenomas (SGPAs) are also extremely rare. Here we report the unique case of a man with the unusual combination of acromegaly from an SGPA, who presented with unilateral hydrocephalus. A 60-year-old man presented with rapid neurological deterioration, bitemporal hemianopia, and acromegalic features. Neuroimaging revealed a large sellar lesion extending superiorly into the left foramen of Monro, causing acute obstructive unilateral hydrocephalus. External ventricular drain placement improved consciousness immediately. Biochemical assessment confirmed acromegaly. Following trans-sphenoidal debulking, histology revealed a mixed gangliocytoma/sparsely-granulated somatotrophinoma. Despite the residual disease, his vision recovered remarkably, low-dose cabergoline controlled residual excess growth hormone (GH) secretion, and the residual tumour has remained extremely stable over 2 years. Hydrocephalus is an extremely rare complication of pituitary lesions, and unilateral hydrocephalus has never been reported previously. GH secretion in SGPAs is more common than for pituitary adenomas in general, raising questions regarding the aetiology and therapeutic approach to this rare combination tumour.Learning pointsPituitary tumours most commonly present with symptoms related to endocrine disturbance or mass effects upon visual pathways (e.g. optic chiasm, nerves in the lateral cavernous sinus). However, extremely rarely, pituitary masses may disrupt cerebrospinal fluid (CSF) circulation resulting in hydrocephalus.Sellar gangliocytomas are very rare tumours and most of them are hybrid tumours with pituitary adenomas (SGPAs).SGPAs are typically indolent and may be functioning or non-functioning tumours.Growth hormone (GH)-producing SGPAs are less likely to respond to somatostatin agonists than classic somatotrophinomas.Primary surgical debulking via a trans-sphenoidal approach was effective in this individual, leading to the restoration of CSF circulation and improvement in visual disturbance, while also negating the need for permanent CSF diversion despite the residual tumour burden.

Minimally Invasive Approaches to the Lateral Cavernous Sinus and Meckel's Cave: Comparison of Transorbital and Subtemporal Endoscopic Techniques

Transorbital and subtemporal keyhole approaches have recently been proposed to approach lesions in the lateral wall of the cavernous sinus (CS) and Meckel's cave (MC). Our goal was to compare these approaches and suggest indications for each of them. Five cadaver heads (10 sides, 40 procedures) were used. The lateral transorbital approaches were carried out without and with the removal of the lateral orbital rim, herein referred to as the lateral transorbital approach (LTOA) and the lateral orbital wall approach (LOWA). The subtemporal approaches were performed without and with the removal of the zygomatic arch, referred to as the subtemporal approach (STA) and the subtemporozygomatic approach (STZA). Five targets were chosen and 2 triangles were created representing thelateral wall of the CS and MC. Stereotactic measurements were quantified to calculate angles of attack, surgical freedom, and temporal lobe retraction for each approach. LTOA presented the smaller horizontal angles of attack. LOWA increased the angles to the same level of STA and STZA. STA and STZA presented larger vertical angles of attack. The surgical freedom presented gradual increase from LTOA to LOWA, STA, and STZA. STA and STZA needed greater temporal lobe retraction for most targets. LTOA is a good option to biopsy a lesion in the lateral wall of the CS and LOWA increased the surgical corridor to work with microsurgical techniques. STA and STZA could be better options when wide exposure is necessary, but temporal lobe retraction should be taken into consideration.

Limits of endoscopic endonasal transpterygoid approach to cavernous sinus and Meckel's cave.

The endoscopic endonasal approach (EEA) to the ventral skull base has greatly increased in popularity over the last two decades. So-called expanded EEA have opened corridors to pathology off-midline, including lesions within the cavernous sinus and Meckel's cave. A standard EEA exposure into the sphenoid sinus allows visualization of the medial cavernous sinus; a transpterygoid approach allows for surgical manipulation of the lateral cavernous sinus and Meckel's cave contents. Pituitary adenomas, meningiomas, and schwannomas are the most common pathologies in this region. This approach to the "front door" of the cavernous sinus and Meckel's cave should be considered complementary to traditional craniotomy techniques as each have benefits and limitations. Herein we review the published literature regarding endoscopic endonasal transpterygoid surgery for pathology in the lateral cavernous sinus and Meckel's cave, and the anatomical and functional limitations of these approaches.

Minimally Invasive Approaches to the Lateral Cavernous Sinus and Meckel's Cave: Comparison of Transorbital and Subtemporal Endoscopic Techniques

Minimally Invasive Approaches to the Lateral Cavernous Sinus and Meckel's Cave: Comparison of Transorbital and Subtemporal Endoscopic Techniques

Reoperative endoscopic endonasal surgery for residual or recurrent pituitary adenomas.

OBJECTIVE Regrowth of the lesion after surgical removal of pituitary adenomas is uncommon unless subtotal resection was originally achieved in the first surgery. Treatment for recurrent tumor can involve surgery or radiotherapy. Locations of residual tumor may vary based on the original approach. The authors evaluated the specific sites of residual or recurrent tumor after different transsphenoidal approaches and describe the surgical outcome of endoscopic endonasal transsphenoidal reoperation. METHODS The authors analyzed a prospectively collected database of a consecutive series of patients who had undergone endoscopic endonasal surgeries for residual or recurrent pituitary adenomas after an original transsphenoidal microscopic or endoscopic surgery. The site of the recurrent tumor and outcome after reoperation were noted and correlated with the primary surgical approach. The chi-square or Fisher exact test was used to compare categorical variables, and the Mann-Whitney U-test was used to compare continuous variables between surgical groups. RESULTS Forty-one patients underwent surgery for residual/recurrent pituitary adenoma from 2004 to 2015 at Weill Cornell Medical College. The previous treatment was a transsphenoidal microscopic (n = 22) and endoscopic endonasal (n = 19) surgery. In 83.3% patients (n = 30/36) there was postoperative residual tumor after the initial surgery. A residual tumor following endonasal endoscopic surgery was less common in the sphenoid sinus (10.5%; 2/19) than it was after microscopic transsphenoidal surgery (72.7%; n =16/22; p = 0.004). Gross-total resection (GTR) was achieved in 58.5%, and either GTR or near-total resection was achieved in 92.7%. Across all cases, the average extent of resection was 93.7%. The rate of GTR was lower in patients with Knosp-Steiner Grade 3-4 invasion (p < 0.0005). Postoperative CSF leak was seen in only one case (2.4%), which stopped with lumbar drainage. Visual fields improved in 52.9% (n = 9/17) of patients and were stable in 47% (n = 8/17). Endocrine remission was achieved in 77.8% (n = 14/18) of cases, 12 by surgery alone and 2 by adjuvant medical (n = 1) and radiation (n = 1) therapy. New diabetes insipidus occurred in 4.9% (n = 2/41) of patients-in one of whom an additional single anterior hormonal axis was compromised-and 9.7% (n = 4/41) of patients had a new anterior pituitary hormonal insufficiency. CONCLUSIONS Endonasal endoscopic reoperation is extremely effective at removing recurrent or residual pituitary adenomas that remain after a prior surgery, and it may be preferable to radiation therapy particularly in symptomatic patients. Achievement of GTR is less common when lateral cavernous sinus invasion is present. The locations of residual/recurrent tumor were more likely sphenoidal and parasellar following a prior microscopic transsphenoidal surgery and sellar following a prior endonasal endoscopic surgery.

Operative surgical nuances of modified extradural temporopolar approach with mini-peeling of dura propria based on cadaveric anatomical study of lateral cavernous structures.

Background:Extradural temporopolar approach (ETA) has been modified as less invasive manner and named as trans-superior orbital fissure (SOF) approach with mini-peeling technique. The present study discusses the operative nuances of this modified technique on the basis of cadaveric study of lateral cavernous structures.Methods:In five consecutive cadaveric specimens, we performed an extradural anterior clinoidectomy with mini-peeling of the dura propria to expose the anterior clinoid process entirely. We also investigated the histological characteristics of the lateral cavernous sinus (CS) between the dura propria and periosteal dura at the SOF, foramen rotundum (FR), and foramen ovale (FO) levels, and of each trigeminal nerve division.Results:Coronal histological examination of the lateral wall of the CS showed invagination of the dura propria and periosteal dura into the SOF. In contrast, no such invagination was observed at the levels of the FR and FO. This finding supports the technical rationale of the only skeletonization of the SOF for peeling of the dura propria but not FR. In addition, our modified ETA method needs only minimal dural incision between the SOF and FR where no cranial nerves are present.Conclusion:Our technical modification of ETA may be recommended for surgical treatment of paraclinoid lesions to reduce the risk of intraoperative neurovascular injury.

Transorbital neuroendoscopic surgery for the treatment of skull base lesions

Transorbital neuroendoscopic surgery (TONES) is a relatively new technique that not only allows access to the contents of the orbit but also the intracranial compartment, including the anterior cranial fossa, middle fossa and lateral cavernous sinus. In this study, we aimed to retrospectively review the largest experience to our knowledge with regards to surgical outcomes of skull base pathologies treated with a TONES procedure. Forty patients (aged 3–89years) underwent 45 TONES procedures between the years of 2006–2013. Pathologies were cerebrospinal fluid leak repair (n=16), traumatic fracture (n=8), tumor (n=11), meningoencephalocele (n=5), hematoma (n=1), and infection (n=4). Three patients had a persistent complication at 3months, including a case each of enophthalmos (unnoticed by patient), epiphora (delayed presentation at 2months requiring dacryocystorhinostomy), and ptosis (improved at 1year). Surgical success was achieved in all patients. Of special import, there were no cases of visual decline, diplopia, or stroke. There was no mortality. To our knowledge this is the first study and largest experience of TONES (level 4 evidence) to detail outcomes with respect to skull base pathologies. Our results indicate that TONES procedures can be performed with minimal morbidity. Further studies are needed to assess equivalency with craniotomy based approaches though this initial report is encouraging.

Lateral transzygomatic middle fossa approach and its extensions: Surgical technique and 3D anatomy

BackgroundVarious approaches to lesions involving the middle fossa and cavernous sinus (CS), with and without posterior fossa extension have been described. In the present study, we describe the surgical technique for the extradural lateral tranzygomatic middle fossa approach and its extensions, highlight relevant 3D anatomy. MethodsSimulations of the lateral transzygomatic middle fossa approach and its extensions were performed in four silicon-injected formalin fixed cadaveric heads. The step-by-step description and relevant anatomy was documented with 3D photographs. ResultThe lateral transzygomatic middle fossa approach is particularly useful for lesions involving the middle fossa with and without CS invasion, extending to the posterior fossa and involving the clinoidal region. This approach incorporates direct lateral positioning of patient, frontotemporal craniotomy with zygomatic arch osteotomy, extradural elevation of the temporal lobe, and delamination of the outer layer of the lateral CS wall. Extradural drilling of the sphenoid wing and anterior clinoid process allows entry into the CS through the superior wall and exposure of the clinoidal segment of the ICA. Posteriorly, drilling the petrous apex allows exposure of the ventral brainstem from trigeminal to facial nerve and can be extended to the interpeduncular fossa by division of the superior petrosal sinus. ConclusionThe present study illustrates 3D anatomical relationships of the lateral transzygomatic middle fossa approach with its extensions. This approach allows wide access to different topographic areas (clinoidal region and clinoidal ICA, the entire CS, and the posterior fossa from the interpeduncular fossa to the facial nerve) via a lateral trajectory. Precise knowledge of technique and anatomy is necessary to properly execute this approach.