Three Cases of Trigeminal Neuralgia with Radiographic Absence of Meckel's Cave.

Trigeminal neuralgia (TN) is a debilitating but treatable disease. Classic TN has referable vascular compression of the trigeminal nerve, but rarely secondary sources of anatomic compression will present, including vascular malformations, aneurysms, or tumors. Understanding the etiology of the patients' symptoms leads to targeted treatment. Three patients presented with symptoms consistent with TN: shooting, paroxysmal pains in the distribution of the trigeminal nerve. However, imaging revealed no vascular conflict at the root entry zone of the trigeminal nerve. Instead, on the affected side Meckel's cave was absent. No other compressive mass lesion was identified. In all three cases, patients were offered both Gamma Knife Radiosurgery and surgical decompression of Meckel's cave. All 3 patients elected to proceed with stereotactic radiation and reported improvement in pain. Many cases of classic TN can be explained by neurovascular conflict at the trigeminal root entry zone, but secondary sources of compression or restriction along the nerve can result in similar symptomology. In this case series, an absent or hypoplastic ipsilateral Meckel's cave may have produced symptoms consistent with TN. Imaging with fine cuts through Meckel's cave is an important diagnostic tool.

Introduction of Meglumine Diatrizoate into the Middle Cranial Fossa: A Rare Fatal Complication of Temporomandibular Joint Arthrography.

The authors here report a rare fatal complication of temporomandibular joint (TMJ) arthrography. A 57-year-old woman suddenly exhibited spasm and dizziness during TMJ arthrography. A multislice CT scanning of head demonstrated a defect in the roof of the glenoid fossa and unanticipated introduction of meglumine diatrizoate into the middle cranial fossa, which should account for neurotoxic symptoms of the patient and could be fatal if not appropriately treated in time. As TMJ puncture is widely performed in clinical practice and generally considered a safe technique, this case might serve as a reminder of the potential risk of the anatomical variation-a defect in the roof of the glenoid fossa-to TMJ clinical practitioners.

Middle Cranial Fossa Approach to Repair Tegmen Defects with Autologous or Alloplastic Graft.

BACKGROUND: Temporal bone tegmen defects may be associated with cerebrospinal fluid (CSF) otorrhea. A variety of techniques have been used for repair. We report our experience with skull base reconstruction for tegmen defects using either autologous or alloplastic grafts. METHODS: A retrospective chart review was performed on patients with tegmen defects treated from 2007 to 2017 at the University Hospital in Columbia, Missouri, USA. Primary outcome measures were analyzed. RESULTS: Twenty-five patients were treated with a middle cranial fossa approach (median age 53, 88% females, median body mass index 34, median follow-up 9 months). Presenting symptoms included CSF leak (92%), hearing loss (44%), imbalance (12%), meningitis (12%), headache (4%), and tinnitus (4%). Most tegmen defects occurred spontaneously (84%) but cholesteatomas (4%), and trauma (12%) also were identified. Pre- and postoperative audiograms were available for 13 patients (52%); 7 (54%) showed objective improvement. Fourteen patients were repaired with autologous bone graft (56%), 7 with alloplastic grafts (28%), and 4 with temporalis fascia only (16%). All patients had resolution of CSF leak. Two patients (8%) suffered wound infections and 3 (12%) had facial and/or petrosal nerve complications. Use of alloplastic graft significantly shortened operative time (allopathic mean 180 minutes vs. autologous mean 208 minutes; P = 0.03). CONCLUSIONS: CSF otorrhea due to tegmen defects can be repaired via a middle fossa craniotomy using either an autologous or alloplastic graft with equivalent outcomes and efficacy, although alloplastic graft helps reduce operating time.

Rinolicuorrea de etiología atípica: encefalocele espontáneo temporal bilateral / Atypical etiology of rhinorrhea: spontaneous bilateral temporal encephalocele

La herniación espontánea de tejido cerebral a través de un defecto óseo y dural a nivel temporal es una rara entidad, siendo todavía más infrecuente que esta circunstancia se produzca de forma bilateral. La presentación suele ser en forma de otorrea intermitente y persistente en el tiempo. La manifestación como rinolicuorraquia es muy poco habitual. El objetivo es presentar este inusual caso de un encefalocele espontáneo bilateral por defecto bilateral del tegmen tympani (AU)

Spontaneous herniation of brain parenchyma through a dural and osseous defect in the temporal bone is a rare entity and a bilateral form is even more infrequent. It usually presents as an intermittent but persistent otorrhea. Manifestation as nose cerebrospinal fluid (CSF) leak is very uncommon. Our objective is presenting this unusual case report of a spontaneous bilateral encephalocele with a bilateral tegmen tympani defect (AU)

Defecto de cobertura del canal semicircular superior y su implicación clínica / Defect of the bony roof in the superior semicircular canal and its clinical implications

Introducción y objetivo: En la actualidad se desconoce la etiología del síndrome de dehiscencia del canal semicircular superior. Nuestro objetivo es analizar y discutir las distintas hipótesis sobre el origen de dicha patología. Métodos: En un estudio sobre 295 temporales se describe desde el punto de vista anatómico y radiológico un caso de una alteración parcial de la cobertura ósea del canal semicircular superior derecho y se compara con el temporal del otro lado. Resultados: Macroscópicamente el canal semicircular superior exhibe un deterioro de su cubierta ósea, constituida exclusivamente por su capa más interna o endostal que separa el canal del conducto semicircular superior. La reconstrucción en el plano Pöschl demuestra que aunque la cubierta está íntegra, su grosor disminuye a lo largo de la curvatura del canal hasta el defecto (0,6 a 0,3 mm).Conclusión: La presencia de defectos parciales en la cobertura ósea del canal semicircular superior con ausencia de sus capas externa y media, sumado a su menor grosor, hacen susceptible al canal para sufrir un segundo evento que podría causar su rotura pudiéndose convertir en una dehiscencia (AU)

Introduction and objective: The aetiology of the superior semicircular canal dehiscence is currently unknown. Our objective was to analyse and discuss different hypotheses about the origin of this pathology. Methods: In this study performed on 295 temporal bones, one case of partial alteration of the bony roof in the right superior semicircular canal was described from the anatomical and radiological points of view, and compared with the temporal bone on the other side. Results: Macroscopically, the superior semicircular canal shows deterioration in the bony roof, which consists exclusively of the inner or endosteal layer that separates the canal from the superior semicircular conduct. The Pöschl plane reconstruction showed a whole bony roof, but its thickness decreased from the canal curvature to the defect (from 0.6 to 0.3 mm). Conclusion: The presence of partial defects in the bony roof of the superior semicircular canal with absence of the external and middle layers, besides its lesser thickness, makes the canal susceptible to suffering a second event. This could produce its fracture and a dehiscence (AU)

The MRI volumetry of the posterior fossa and its substructures in trigeminal neuralgia: a validated study.

PURPOSE: Our aim was to determine whether the anatomical configuration of the posterior fossa and its substructures might represent a predisposition factor for the occurrence of clinical neurovascular conflict in trigeminal neuralgia (TN). METHODS: We used MRI volumetry in 18 patients with TN and 15 controls. The volume of the pontomesencephalic cistern, Meckel's cave and the trigeminal nerve on the clinical and non-affected sides was compared. The reliability has been assessed in all measurements. RESULTS: The posterior fossa volume was not different in the clinical and control groups; there was no difference between the affected and non-affected sides when measuring the pontomesencephalic cistern and Meckel's cave volume either. The volume of the clinically affected trigeminal nerve was significantly reduced, but with a higher error of measurement. CONCLUSIONS: We did not find any association between the clinical neurovascular conflict (NVC) and the size of the posterior fossa and its substructures. MRI volumetry may show the atrophy of the affected trigeminal nerve in clinical NVC.

Sternberg's canal: fact or fiction?

BACKGROUND: Sternberg's (lateral craniopharyngeal) canal was originally described in anatomic studies as a membranous space in the lateral wall of the sphenoid sinus. The canal has been etiologically associated with lateral sphenoid sinus "spontaneous" cerebrospinal fluid (CSF) leaks. A patent Sternberg's canal has been reported in up to 4% of adults, and persistent vestiges have been reported in up to 30%. However, no modern studies analyzing high-resolution CT scans have been published. METHODS: A consecutive analysis of 1000 high-resolution CT scans of sphenoid bones was performed. Scans were analyzed for a lateral recess, bony defects, arachnoid pits, and holes possibly representing Sternberg's canal. Data were compared with a case series of lateral sphenoid CSF leaks. RESULTS: Average patient age was 38.7 years (10-92 years). A sphenoid lateral recess was present in 35.3% (17.4% bilateral) of cases. Arachnoid pits were present on the floor of the middle cranial fossa in 23.4% of cases. Seven skull base defects were identified. Only one traveling medial to V2 resembled the description of Sternberg's canal. In contrast, a case series of 25 patients with lateral sphenoid sinus CSF leaks all had a lateral recess, defects, and arachnoid pits lateral to V2 (p < 0.00001). CONCLUSION: Sternberg's canal as historically defined is not nearly as prevalent as previously reported. Furthermore, the presence of arachnoid pits in all sphenoid CSF leaks and the predominant leak location lateral to the sites of fusion of ossification centers suggests that the leaks are acquired. Contributing factors may include arachnoid pits/weaknesses in the skull base and intracranial hypertension.

Spontaneous middle fossa encephalocele and cerebrospinal fluid leakage: diagnosis and management.

OBJECTIVE: To evaluate the clinical presentation, operative findings, and surgical management of patients with spontaneous middle fossa encephalocele (SMFE) and cerebrospinal fluid (CSF) leakage repaired using a middle fossa craniotomy (MFC) approach. STUDY DESIGN: Retrospective. SETTING: Tertiary referral center. PATIENTS: Fifteen consecutive patients with 16 SMFE repaired using an MFC approach between January 1999 and April 2006 were included. INTERVENTIONS: Patients were evaluated clinically and radiologically with computed tomography or magnetic resonance imaging. Encephaloceles were approached via MFC, and the cranial base was repaired in multilayered fashion using a variety of materials, including hydroxyapatite cement. Patients were followed clinically after discharge. MAIN OUTCOME MEASURES: Postoperative complications, including CSF leak and the need for surgical revision, are evaluated. Patient factors, diagnostic testing, and operative findings are reviewed. RESULTS: Diagnosis was made using clinical and radiologic evaluation in most patients. Beta2-transferrin testing was occasionally used in the diagnostic workup. Intraoperatively, multiple defects of the floor of the middle fossa were found in more than half of patients. Fifteen SMFE in 14 patients were successfully repaired via MFC alone. One patient required revision with a combined transmastoid/MFC approach due to recurrent CSF leakage. Hydroxyapatite cement was used for repair of the cranial base in 9 patients without complication. CONCLUSION: An MFC approach can be used to repair SMFE with CSF leakage with a high level of success. Hydroxyapatite cement is a safe and useful adjunct to aid in reconstruction of the cranial base defects in cases of SMFE.

Intracranial aneurysm and arachnoid cyst: a rare association between two cerebral malformations.

Intracranial aneurysms and arachnoid cysts are cerebral disorders of a high prevalence. However, association between both malformations is a rare finding. The aim was to analyse this association with regard to the different clinical presentations according to the haemorrhage types, as well as the pathogenesis of this association. We searched the English language literature in MEDLINE database in order to include all manuscripts in which this association was found. A new case of a 55-year-old man with a large posterior communicating artery aneurysm and a middle cranial fossa arachnoid cyst presenting with headache and seizure was added to review of the literature and presented as an illustrative case. Nine cases were found. Six were male and three were female. The mean age was 42 years (range 29-66 years). All but one arachnoid cysts were located at middle cranial fossa, aneurysms arose from middle cerebral artery in three cases, internal carotid artery bifurcation in two cases, posterior communicating segment of carotid artery in two cases, anterior communicating artery in one case and azygos pericallosal artery in one case. Clinical presentation was related to aneurysmal rupture in six cases (subarachnoid haemorrhage in four, subdural haematoma in one and intracystic haematoma in two) and related to arachnoid cysts in three cases, where the most common symptoms were seizures and headache. Association between intracranial aneurysms and arachnoid cysts is a rare finding that can present with signs and symptoms related to aneurysm rupture, or with mass effect and seizures related to the cyst. The aneurysmal haemorrhage may be atypical, since it can be into the subarachnoid space, into the arachnoid cyst, or into the subdural space.

Two consecutive dural arteriovenous fistulae in a child: a case report of successful treatment with gamma knife radiosurgery.

INTRODUCTION: The occurrence of dural arteriovenous fistulae in children is quite rare. Endovascular embolization is typically the first line treatment. In general, Gamma Knife radiosurgery is used as adjuvant treatment and seldom performed as the first line treatment in children. DISCUSSION: We report a case of a 27-month-old girl who presented with an initial dural arteriovenous fistula (AVF) located at anterior base of the left middle cranial fossa. She subsequently developed another dural AVF over the left transverse-sigmoid sinus region 2 years later. CONCLUSION: Both fistulae were successfully obliterated with Gamma Knife radiosurgery.

Idiopathic hypogonadotrophic hypogonadism associated with arachnoid cyst of the middle fossa and forebrain anomalies: presentation of an unusual case.

We report a 22-yr-old male patient with hypogonadotrophic hypogonadism (HH) associated with a giant middle fossa arachnoid cyst (AC) diagnosed by magnetic resonance imaging (MRI). He presented with pubertal and growth delay. He also had learning disabilities and anosmia. Laboratory investigation revealed pre-pubertal levels of testosterone and normal results of the combined test of anterior pituitary function, except for in GnRH acute and prolonged test. Cranial MRI showed an AC in left middle fossa with expansion to suprasellar cisterna and several abnormalities like left temporal lobe hypoplasia, left optic tract and bilateral olfactory bulb hypoplasia and left hypothalamic hypoplasia.

[A case report of sphenoidal encephalocele presenting with cerebral spinal fluid rhinorrhea].

Sphenoidal encephalocele is a rare congenital anomaly. We report a case of sphenoidal encephalocele presenting with cerebral spinal fluid rhinorrhea. A 53-years-old man suffered recurrent fever and rhinorrhea. Computed tomography demonstrated a low density area extending from the left middle cranial fossa into the left sphenoidal sinus. Bone defect was identified in the medial surface of the left middle cranial fossa. Magnetic resonance imaging with contrast medium demonstrated peripheral enhancement of the lesion. We diagnosed the lesion as sphenoidal encephalocele. Surgical repair and amputation of the encaphalocele was performed. Sphenoidal encaphalocele should be considered as a possible diagnosis for recurrent fever and rhinorrhea.

Study on skull asymmetry.

The aim of this study is to determine the type of skull as well as to examine its internal appearance and configuration of skull base. Special attention is given to the direction and position of the pyramid of the temporal bone, the volume and appearance of all the three cranial fossas, and the direction and appearance of crista alaris--all of those compared to the skull type. Considering the obtained results (specially for crista alaris and middle fossa) we can ascertain outstanding independence of sphenoid bone and its parts in the formation of cranial base. Located in the middle of the skull, in front of strong pyramids transversal axis and two vertical axis, frontal crest and internal occipital crest, it by itself with her lesser wing presents an important transversal axis of cranial base. Cases in which crista alaris with its position does not follow the type of skull (in 20 % cases crista alaris does not follow skull protuberances), may probably be explained by strong and independent development of this bone, which is placed among other bones of cranial base like a peg. It also, by itself dictates form and configuration of the middle part of skull. That is also confirmed by middle fossa which, according to its position in the middle of cranial base and relation with sphenoid bone, shows significant deviation with respect to posterior fossa (follows the type of skull in 47 % cases).