Meckel's cave epidermoid with trigeminal neuralgia: CT findings

Avoiding the Blinded Funnel: A Combined Single Piece Fronto-Temporo-Orbito-Zygomatic Craniotomy Endoscopic-Assisted Approach with Multimodal Assistance for an Epidermoid Tumor of Meckel's Cave-Case Report

A Meckel's cave tumor poses a great challenge because of the peculiar neurovascular structure of the area and the deep location. Multiple surgical approaches have been designed for this area. In this report, we describe a case treated with a combined one step single piece fronto-temporo-orbito-zygomatic craniotomy (FTOZ) endoscopic-assisted approach for the treatment of an epidermoid tumor of Meckel's cave. A 51-year-old woman presented with a clinical history of left trigeminal neuralgia and paresthesia. CT imaging revealed a left basal temporal tumor. MR showed a tumor located in Meckel's cave near the cavernous sinus, with a good enhancement after gadolinium administration. The tumor was resected through a lateral basal subtemporal extradural approach followed by an intradural approach using intraoperative neuronavigation, endoscopic assistance, neurophysiological monitoring, and an intraoperative ultrasound probe. The lesion was completely removed. No new onset neurological damage has occurred. The symptoms improved following surgery. The aesthetic appearance of the patient was respected. The combined approach with a single piece fronto-temporo-orbito-zygomatic craniotomy has enabled us to work on a wider operating field to completely remove the lesion avoiding blind spots.

A case series of percutaneous transforamen ovale biopsies in cavernous sinus lesions

BACKGROUND

The majority of cavernous sinus lesions are meningiomas, for which treatment (fractioned radiotherapy or radiosurgery), if indicated, is usually initiated upon image-based diagnosis. However, this region can be affected by a wide variety of pathological processes and the risk of misdiagnosis exists. As pathological diagnosis can be obtained by biopsy through the foramen ovale in selected cases, we asked the question as to whether systematically performing this procedure before treatment would provide additional, relevant diagnostic information.

METHODS

All the cases referred to our department between January 2008 and December 2019 for cavernous sinus lesions that were considered for treatment and anatomically suitable for transforamen ovale biopsy were included. Outcomes and subsequent treatment or follow-up data were collected.

RESULTS

Thirty-five patients were included. Twenty-six were highly suspected to have meningioma or schwannoma at imaging, among whom biopsy allowed diagnosis confirmation in 17 cases (65%). For the nine patients for whom biopsy was indicated upon suspected malignancy or inflammatory disease on imaging, biopsy revealed three meningiomas and one lymphoma and was not contributory in five cases (56%), three of which underwent open surgery. Three patients (8.5%) had persistent neuralgia at the last follow-up.

CONCLUSIONS

When cavernous sinus meningioma or schwannoma is highly suspected upon predefined imaging criteria by an experienced neuroradiologist, invasive exploration before treatment does not seem to be indicated. Otherwise, transforamen ovale biopsy might be consider in selected cases as a minimally invasive option to obtain pathological analysis.

Endoscopic Subtemporal Epidural Key-Hole Approach: Quantitative Anatomic Analysis of Three Surgical Corridors

BACKGROUND

The endoscope-assisted subtemporal key-hole epidural approach (ESKEA) has been recently described. The aim of this study was to measure working volumes and exposure of key areas of the middle cranial fossa provided by this approach.

METHODS

Four fresh frozen cadaver heads were dissected to analyze 3 modular corridors (1A, 1B, and 2) harvested through ESKEA. A step-by-step dissection was performed, and key anatomic landmarks were recorded. A GTxEyesII-ApproachViewer was used to quantify the working volume and exposure of 4 different regions (sphenoorbital, parasellar, superior petrous apex, and squamopetrous). For each corridor, 3 incremental degrees of temporal dural retraction (5, 10, and 15 mm) were tested.

RESULTS

The working volume of all corridors progressively increased with degree of retraction: Corridors 1A, 1B, and 2 showed a gain in working volume of 21%, 27%, and 19% from 5 mm to 10 mm retraction, respectively, and a gain of 40%, 45%, and 44% from 5 mm to 15 mm retraction, respectively. The sphenoorbital area was exposed (27%-45%) through corridor 1A, and exposure significantly increased with the degree of retraction. Corridor 1B provided optimal exposure of parasellar areas (86%-100%) and superior petrous apex (70%-87%) regardless of the degree of retraction. The squamopetrous area was satisfactorily addressed through corridor 2 (88%) only with the highest degree of retraction.

CONCLUSIONS

ESKEA can be conceived as a modular approach: the 3 surgical corridors have specific working volumes, which are clearly influenced by the degree of temporal lobe retraction, and provide exposure of different middle cranial fossa areas.

Trigeminal Neuralgia Due to a Small Meckel's Cave Epidermoid Tumor: Surgery Using an Extradural Corridor

Tumors at the petrous apex are associated with a variety of symptoms, which most often involve the trigeminal nerve. The authors present a rare case of a small epidermoid tumor in Meckel's cave that caused medically refractory trigeminal neuralgia. The surgical challenge associated with approaches to such lesions is discussed. The skull base tumor was excised completely through a small temporal craniotomy. The practicality of neuronavigation in reaching the petrous apex using a small extradural window is presented.

The importance of routine magnetic resonance imaging in trigeminal neuralgia diagnosis

The aim of the study was to determine the frequency of structural lesions diagnosed on magnetic resonance imaging (MRI) in a sample of patients with trigeminal neuralgia (TN) and to compare history and clinical features between the groups with and without structural lesions. Clinical records and MRI findings of 42 consecutive patients diagnosed with TN at the National Dental Centre, Singapore, and who underwent routine MRI examinations at diagnostic workup between April 1997 and March 1999 were retrospectively studied. Of these, 6 (14.3%; 95% confidence interval, 0 to 28.8%) were diagnosed with an associated structural lesion. Mean age of the group with structural lesions was 53.3 years (standard deviation, 10.9 years) at presentation, there was female predominance (M:F = 1:2), and all (100.0%) gave a typical pain history and had unilateral involvement of a single division of the trigeminal nerve. Two patients (33.3%) had other cranial nerve abnormalities. Three patients (50.0%) had complete, 2 patients (33.3%) had partial, and 1 patient (16.7%) had poor response to medical therapy. None of these variables was statistically different from the group without structural lesions (cranial nerve abnormalities were not compared). In conclusion, the frequency of structural lesions associated with TN in our sample was relatively high. It is not possible to reliably identify high risk patients for selective MRI indication on the basis of history and clinical features. It may be prudent to consider routine MRI for all patients with TN to exclude structural lesions.

Epidermoid tumor within Meckel's cave--case report

A rare case of an epidermoid tumor lying within Meckel's cave is reported. A 27-year-old housewife presented with complaints of right facial hypesthesia for two and a half years. On examination she had partial loss of touch sensation in the right trigeminal nerve distribution. Magnetic resonance imaging revealed a tumor located at the right petrous apex and cavernous sinus. The epidermoid tumor was excised through a lateral basal subtemporal approach. The symptoms resolved following surgery.

Neurovascular relationships in the posterior cranial fossa, with special reference to trigeminal neuralgia. 2. Neurovascular compression of the trigeminal nerve in cadaveric controls and patients with trigeminal neuralgia: quantification and influence of method

The theory of neurovascular compression has been tested by comparing the neurovascular relationships of the trigeminal nerve in a series of operative observations in patients affected by trigeminal neuralgia with those of a control series of cadavers matched for age, sex and side, in which operative conditions were simulated during simultaneous arterial and venous injection--filling to physiological pressures, as described in Part 1 of this article. A rigorous system of classification of neurovascular relations is defined. In 46 patients with trigeminal neuralgia, 91% had a vessel in contact with the trigeminal nerve adjacent to the brain stem and in all but one a groove was created. Multiple vessels were found in 17% and in two both the root entry zone and lateral portions of the nerve were compressed. However, in 35 randomly selected fresh cadavers, not known to have suffered neurological disease, 14% had neurovascular contact and a further 26% had vessels "near" to the nerve. No vessel was associated with a groove and no multiple vessels, or sites of contact, were encountered. The difference between the control cadavers and the operative findings in patients related to an increase in the number of arteries. Injection-filling of the cadaveric vessels doubled the numbers of vessels in contact with, and near to the nerve. The technique used and system of classification applied showed an association between arterial contact and trigeminal neuralgia. The technique may provide a suitable method for the testing of the neurovascular compression theory in other conditions.

Association of vascular compression in trigeminal neuralgia versus other "facial pain syndromes" by magnetic resonance imaging

Magnetic resonance imaging was performed in 13 patients with trigeminal neuralgia and 18 control patients with facial pain of other types. Among trigeminal neuralgia patients, eight (62%) had vessels seen abutting, or immediately adjacent to, the trigeminal nerve on the side of their symptoms. Only three control patients (17%) had such vessels. The proportion of patients having a trigeminal region vessel associated with their symptoms was significantly higher in patients with trigeminal neuralgia than in controls (p = 0.0086). These findings provide evidence supporting the theory that trigeminal neuralgia is associated with vascular compression of the fifth cranial nerve.

Transtentorial epidermoid cysts

Epidermoid cysts may occur simultaneously above and below the tentorium. Eleven patients with involvement of both infra- and supra-tentorial cisterns are presented. In two cases the epidermoid, located mainly in the cerebello-pontine angle, spread into the middle cranial fossa; in three the epidermoid extended from the parasellar cisterns to the posterior cranial fossa; in six patients the epidermoid, enlarging the tentorial notch, occupied extensively both cranial fossae. The surgical approach was influenced both by the experience of the surgeon and by the main extension of the epidermoid. Total removal was feasible in two patients only but only one of the eleven patients had a recurrence of the epidermoid. The long term results appear to be unrelated to the size of the epidermoid and to the choice of approach.