Bilateral duplication of the abducens nerve - case study.

The abducens nerve is characterized by a long intracranial course and complex topographical relationships. Anatomical knowledge may help to understand both the etiology and clinical symptoms of abducens nerve palsy. Typically, the single trunk of the abducens nerve travels on both sides. However, occasionally different variants of unilateral or bilateral duplications of the abducens nerve may be observed. The presented paper is a detailed anatomical description of bilateral duplication of the abducens nerve, with atypical appearance of the nerve in the cavernous sinus and normal distribution within the lateral rectus muscle on both sides of one cadaver. On the right side both trunks of the abducens nerve fused within the subarachnoid space and pierced the dura mater together. On the left side both trunks of the duplicated abducens nerve pierced the dura mater separately, entered the petrous apex separately and fused just below the petrosphenoidal ligament. Within the cavernous sinus the nerve divided once again into two filaments, which reunited into one trunk a er crossing the horizontal segment of the intracavernous part of internal carotid artery. The orbital segments of the abducens nerve showed a typical course on both sides. Duplication of the abducens nerve is anatomical variation which should be taken into account during diagnostic and surgical procedures performed within the petroclival region and cavernous sinus.

Mandibular Myalgia and Miniscule Meckel's Caves.

Trigeminal neuropathy manifests as episodic sharp, shooting pain in the maxillofacial region. Contributory etiologies are myriad, ranging from central pathology affecting its origin in the brainstem to peripheral processes affecting their distal-most insertion sites. We present a case of bilateral hypoplastic Meckel's caves in an adult patient leading to the clinical symptomology of trigeminal neuralgia. To the best of our knowledge, this is the only report of its kind highlighting this anatomic variant.

[Malformations and abnormalities of the petrous portion of the temporal bone]. / Fehlbildungen und Missbildungen des Felsenbeins.

High-resolution computed tomography (HRCT) is the procedure of choice in the diagnostics of abnormalities of the middle and inner ear. It allows a detailed presentation of anatomical features and achieves the prerequisites for selection of the various therapeutic options. The highly diverse abnormalities can be described using detailed imaging analyses. Malformations with an abnormally developed modiolus are assumed to be early embryological defects, such as the classical Mondini dysplasia. The essential therapeutic option for middle ear deformities is still a cochlear implant. The domain of magnetic resonance imaging (MRI) is not only in the analysis of the cochlear nerve and for exclusion of fibrosis or ossification of the labyrinth but is also able to visualize details of isolated malformations, such as an extended vestibular aqueduct or subtle alterations to the vestibule or can visualize them better in comparison to CT. Radiological diagnostics are used not only for classification but also to recognize typical clinical problem situations and play a key role in the diagnostics of hearing disorders and selection of the optimal therapeutic procedure.

Congenital aplasia of the external ear canal and total dehiscence of mastoid-tympanic segment of the facial nerve as a cause of recurrent facial paralysis.

Facial nerve (FN) macrodehiscence, in contrast to microdehiscence, generally occurs as a result of chronic otitis media and is rarely seen congenitally. A patient with normal hearing who had no history of ear disease or ear operation came to the clinic with recurrent facial paralysis (FP) and frequent blockage of the external ear canal with epithelial debris complaints. In the explorative ear surgery, we observed that the posterior wall of the external ear canal or tympanic ring was absent, a large external ear cavity was covered with a thin skin, the FN was under the skin, and the tympanic-mastoid segment of the FN and chorda tympani extending to the stylomastoid foramen was completely open. FP episodes were associated with the unprotected FN.To prevent an attack of FP, and to self-clean the external ears, mastoid obliteration surgery was performed, and the mastoid segment of the FN was covered with a conchal cartilage graft. This case was diagnosed as congenital aplasia of the external ear canal due to the tympanic bone aplasia-mastoid bone hypoplasia, and the dehiscence of the mastoid-tympanic segment of the FN, and as a cause of recurrent FP, has never to date been identified.

Coexistence of a pseudolesion and a true lesion in the same location: a rare misleading imaging finding.

Congenital cholesteatoma and asymmetric fatty marrow are both common masses that appear as imaging "lesions" in the petrous apex, but their treatment modalities are very different. Accurate preoperative recognition by computed tomography and magnetic resonance imaging is, therefore, important for planning appropriate management strategies. We report a case with coexisting congenital cholesteatoma and asymmetric fatty marrow in the same petrous bone. The 2 lesions were indistinguishable on high-resolution computed tomographic images and were only identified on fat-suppressed magnetic resonance imaging sequences. This is the first report of these 2 lesions coexisting, leading to a rare misleading imaging finding.

Meckel's cave anatomic variation.

We present a rare radiographic abnormality found in a patient who consulted us for progressive left hearing loss.

Trigeminal Neuralgia Due to Petrosal Bone Deformity.

BACKGROUND: There have been a few previous reports of trigeminal neuralgia caused by bony structures. We report a rare case of trigeminal neuralgia caused by petrous bone deformity. CASE DESCRIPTION: A-43-year-old man with facial pain in the left maxillary and mandibular divisions of the trigeminal nerve was referred to our hospital. Computed tomography showed bone hyperplasia protruding into the left cerebellopontine cistern, compressing the left trigeminal nerve. Administration of carbamazepine ameliorated facial pain, but the effect was unsatisfactory, and microvascular decompression was performed through the anterior transpetrosal approach. The protruding petrous bone was drilled out to release compression of the trigeminal nerve, thus straightening the deviated trajectory of the nerve. The superior cerebellar artery adjacent to the thickened petrosal bone seemed to have compressed the trigeminal nerve and was also transposed. The facial pain disappeared completely after microvascular decompression surgery. CONCLUSIONS: The anterior transpetrosal approach is an appropriate and essential strategy for trigeminal neuralgia caused by petrous bone deformity of the petrous apex.

Incidence and morphometry of sellar bridges and related foramina in dry skulls: Their significance in middle cranial fossa surgery.

PURPOSE: The current study investigated the incidence, morphology and morphometry of the ossified ligaments expanding between petrous bone and posterior clinoid processes and in between the anterior, middle and posterior clinoid processes. Side symmetry, gender dimorphism and age influence were also studied. MATERIALS AND METHODS: A total of 123 adult Greek dry skulls were observed. RESULTS: A caroticoclinoid bar (CCB) was found in 60.2%. Partial CCBs appeared more commonly (36.6%) than complete (23.6%). The caroticoclinoid foramen (CCF) was symmetrical on both sides and genders. An anterior interclinoid, a posterior petroclinoid and a partial posterior interclinoid bar appeared in 19.5%, 6.5% and 2.4%, respectively. Osseous spurs posterolateral to the posterior clinoid process were present in 5.7%. CONCLUSION: The study highlights important morphometric details about osseous bars of the sella region and the related CCF in Greek skulls. Notable differences in the incidence of these bars in Greek individuals compared with findings from other populations highlight the growing awareness of ethnic differences in skull base landmarks. Variations and surgically oriented measurements provided by this study may benefit clinicians involved in the treatment of the middle cranial fossa pathology, enriching understanding of the complicated regional anatomy. Preoperative sellar area mapping is essential, by using computed tomography images, since modification of the surgical approach may be required in cases of severe ossification.

Facial diplegia revealing ventriculoperitoneal shunt failure in a patient with Crouzon syndrome. Case report.

The authors report on the case of a 15-year-old boy with Crouzon syndrome (CS) who presented with headache and facial diplegia. He had undergone several craniofacial interventions and a posterior fossa decompression for tonsillar herniation caused by the CS. A ventriculoperitoneal (VP) shunt had been inserted for hydrocephalus. Emergency computed tomography (CT) disclosed slight dilation of the ventricular cavities compared with their appearance on a baseline CT scan. Magnetic resonance imaging showed a deformed brainstem but no compression at the occipital foramen; there was no apparent explanation for the facial diplegia. The neuroophthalmological examination revealed neither papilledema nor oculomotor palsy. Electromyography confirmed incomplete peripheral facial diplegia. The patient underwent emergency shunt revision, during which complete obstruction of the ventricular catheter and severe cerebrospinal fluid hypertension were found. After surgery, cranial hypertension symptoms completely resolved and the facial diplegia improved slowly with a persistent and incomplete right superior facial palsy. Cranial 3D CT scanning reconstructions and brain magnetic resonance imaging demonstrated severe petrous bone distortion that could have been responsible for direct stretching injuries on the facial nerves at the level of the internal acoustic meatus. The present case represents the first reported occurrence of VP shunt failure as revealed by a facial palsy; the authors discuss the pathophysiology of facial palsy in intracranial hypertension.

Vertically oriented internal auditory canal in an 8-year-old with hearing loss.

To report a unique orientation of the internal auditory canal and possible association with congenital hearing loss. Retrospective chart review of an 8-year-old Hispanic male with a mixed hearing loss. Uniquely abnormal orientation of the internal auditory canal in a patient with apparently normal cochleovestibular structures and a mixed hearing loss. A vertically oriented IAC is a rarely described anatomical anomaly of the temporal bone that may have associations with congenital hearing loss.

Surgically Cured, Relapsed Pneumococcal Meningitis Due to Bone Defects, Non-invasively Identified by Three-dimensional Multi-detector Computed Tomography.

A 43-year-old Japanese man presented with a history of bacterial meningitis (BM). He was admitted to our department with a one-day history of headache and was diagnosed with relapse of BM based on the cerebrospinal fluid findings. The conventional imaging studies showed serial findings suggesting left otitis media, a temporal cephalocele, and meningitis. Three-dimensional multi-detector computed tomography (3D-MDCT) showed left petrous bone defects caused by the otitis media, and curative surgical treatment was performed. Skull bone structural abnormalities should be considered a cause of relapsed BM. 3D-MDCT was useful for revealing the causal minimal bone abnormality and performing pre-surgical mapping.

Recurrent meningitis associated with a petrous apex cephalocele.

We present the case of a 6-year-old girl with recurrent bacterial meningitis and cerebrospinal fluid (CSF) rhinorrhea associated with a petrous apex cephalocele (PAC). We diagnosed her by means of three-dimensional computed tomography (CT) and heavily T2-weighted magnetic resonance imaging (MRI). Petrous apex cephaloceles are usually an asymptomatic incidental finding in adults; however, they should be considered as a possible cause of CSF rhinorrhea, otorrhea, and recurrent meningitis in children.

Stenosis of the internal auditory meatus masquerading as bilateral vestibular schwannomas: a cautionary tale.

Stenotic malformations of the internal auditory meatus (IAM) are rare. They are known to symptomatically mimic vestibular schwannomas leading to potential diagnostic error. We present a case (along with literature review) where a stenotic IAM was clinically and radiologically misdiagnosed as a vestibular schwannoma.

An anencephalic monocephalus diprosopus "headed twin": postmortem and CT findings with emphasis on the cranial bones.

Monocephalus diprosopus is a form of conjoined twinning characterized by a single body, one unusual head and two faces or a spectrum of duplication of the craniofacial structures. Such cases have been mainly described according to postmortem pathologic examination. This presented case is a 26-week-stillborn female fetus, with unusual facial appearance with four eyes, two mouths, two noses, two ears and a defective cranial vault. To our knowledge, a detailed computerized tomography (CT) examination of the aberrant facial and cranial bones of such a case has not been reported to date. In this reported case, we present an anencephalic monocephalus diprosopus "headed twin", and describe the CT findings with emphasis on the cranial bones.

[Influence of trigeminal nerve lesion on facial growth: study of two cases of Goldenhar syndrome]. / Influence de l'atteinte trigéminale sur la croissance faciale : étude de deux cas de syndrome de Goldenhar.

INTRODUCTION: This cases report confirms the hypothesis that embryonic and maxillofacial growth are influenced by the peripheral nervous system, including the trigeminal nerve (V). So, it's interesting to use the stigma of the trigeminal nerve as landmarks to analyze the maxillofacial volume and understand its growth. The aim of this study is to evaluate the validity of the three-dimensional cephalometric analysis of Treil based on trigeminal landmarks. CASE PRESENTATION: The first case is a caucasian female child with Goldenhar syndrome. The second case is a caucasian male adult affected by the same syndrome. In both cases, brain MRI showed an unilateral trigeminal nerve lesion, ipsilateral to the facial dysmorphia. CONCLUSION: The results of this radiological study tend to prove the primary role of the trigeminal nerve in craniofacial growth. These cases demonstrate the validity of the theory of Moss. They are one of anatomo-functional justifications of the three-dimensional cephalometric biometry of Treil based on trigeminal nerve landmarks.

Petrous angle and trigeminal neuralgia.

The angle of the petrous portion of the temporal bone was measured at the site where it is crossed by the trigeminal nerve. Measurement was facilitated by using the impression techniques of dentistry to produce a plaster model of the bone, and the model was then sawn across to show the angle clearly. Considerable variation was found. Certain bone irregularities were observed and these could also conceivably be factors in the causation of trigeminal neuralgia. An attempt to reveal the angle of the petrous bone by radiology was successful in some cases but not in others. Further investigation along these lines might be of value in patients suffering from idiopathic trigeminal neuralgia.

Pendred syndrome--100 years of underascertainment?

Pendred syndrome is an autosomal recessive condition classically characterized by deafness and goitre. Since both cochlear and thyroid pathology are required to secure the diagnosis, it is unclear whether the condition might present without the classical features. The perchlorate discharge test, the gold-standard investigation for Pendred syndrome, is non-specific, and in the absence of alternative means of confirming the diagnosis, its sensitivity is unknown. We used the recent mapping of the gene to chromosome 7q to identify pedigrees with a likely diagnosis of Pendred syndrome, and assessed the prevalence of clinical parameters of disease in affected patients. Thirty-six familial cases showed co-segregation between disease and the Pendred syndrome locus on chromosome 7q. Clinical and investigative findings were compared in index cases (n = 18) vs. affected siblings (n = 18). The overall prevalence of goitre was 73%, higher in index cases (94%) than in siblings (56%), many of whom had not previously been considered to have the condition. One perchlorate discharge test was false-negative (2.9%). Radiological malformations of the cochlea were identified in 86% of cases. Securing a diagnosis of Pendred syndrome may be difficult, especially in the single case. The perchlorate discharge test, although valuable, is difficult to undertake in the younger patient, and radiology may assist in diagnosing such patients.

Elevation of the petrous bone caused by hyperplasia of the occipital bone presenting as hemifacial spasm: diagnostic values of magnetic resonance imaging and three-dimensional computed tomographic images in a bone anomaly.

A case of elevation of the petrous bone due to hyperplasia of the occipital bone presenting as hemifacial spasm is reported. A 44-year-old man sought treatment for twitching of the buccal muscles on the right side that progressed rapidly in severity within 2 weeks of the onset. The anatomical details of the petrous and occipital bones were delineated clearly by computed tomographic scans of a bone window level. Details of the brain stem were shown by magnetic resonance images. The bone anomaly was displayed more realistically by three-dimensional computed tomographic reconstructions. The faithful representation of structures with these radiological studies should be mandatory, to prepare the surgical planning of such a complicated bone anomaly.

Endoscopic treatment of an oral cephalocele. Case report.

This report describes an unusual cephalocele originating in the temporobasal region and protruding through the sphenopetral area into the oral cavity. A rapid and nonaggressive endoscopic procedure was performed. The relationship between this type of cephalocele, spontaneous anteroinferior temporal encephaloceles, and nasopharyngeal brain heterotopia is discussed.