Evaluation and Treatment of Patients with Small Posterior Cranial Fossa and Chiari Malformation, Types 0 and 1

The diagnosis of Chiari I malformation is straightforward in patients with typical signs and symptoms of Chiari I malformation and magnetic resonance imaging (MRI) confirming ≥5 mm of cerebellar tonsillar ectopia, with or without a syrinx. However, in many cases, Chiari I malformation is discovered incidentally on MRI to evaluate global headache, cervical radiculopathy, or other conditions. In those cases, the clinician must consider if cerebellar tonsillar ectopia is related to the presenting symptoms. Surgical decompression of the cerebellar tonsils and foramen magnum in patients with symptomatic Chiari I malformation effectively relieves suboccipital headache, reduces syrinx distension, and arrests syringomyelia progression. Neurosurgeons must avoid operative treatments decompressing incidental tonsillar ectopia, not causing symptoms. Such procedures unnecessarily place patients at risk of operative complications and tissue injuries related to surgical exploration. This chapter reviews the typical signs and symptoms of Chiari I malformation and its variant, Chiari 0 malformation, which has <5 mm of cerebellar tonsillar ectopia and is often associated with syringomyelia. Chiari I and Chiari 0 malformations are associated with incomplete occipital bone development, reduced volume and height of the posterior fossa, tonsillar ectopia, and compression of the neural elements and cerebrospinal fluid (CSF) pathways at the foramen magnum. Linear, angular, cross-sectional area, and volume measurements of the posterior fossa, craniocervical junction, and upper cervical spine identify morphometric abnormalities in Chiari I and Chiari 0 malformation patients. Chiari 0 patients respond like Chiari I patients to foramen magnum decompression and should not be excluded from surgical treatment because their tonsillar ectopia is <5 mm. The authors recommend the adoption of diagnostic criteria for Chiari 0 malformation without syringomyelia. This chapter provides updated information and guidance to the physicians managing Chiari I and Chiari 0 malformation patients and neuroscientists interested in Chiari malformations.

Mapping sexual dimorphism signal in the human cranium

The study of sexual dimorphism in human crania has important applications in the fields of human evolution and human osteology. Current, the identification of sex from cranial morphology relies on manual visual inspection of identifiable anatomical features, which can lead to bias due to user's expertise. We developed a landmark-based approach to automatically map the sexual dimorphism signal on the human cranium. We used a sex-known sample of 228 individuals from different geographical locations to identify which cranial regions are most sexually dimorphic taking into account shape, form and size. Our results, which align with standard protocols, show that glabellar and supraciliary regions, the mastoid process and the nasal region are the most sexually dimorphic traits (with an accuracy of 73%). The accuracy increased to 77% if they were considered together. Surprisingly the occipital external protuberance resulted to be not sexually dimorphic but mainly related to variations in size. Our approach here applied could be expanded to map other variable signals on skeletal morphology.

Investigating intentional cranial modification: A hybridized two-dimensional/three-dimensional study of the Hirota site, Tanegashima, Japan

Intentional cranial modification has a long history, being a ubiquitous practice in many cultures around the world for millennia. The crania excavated at the Hirota site on Tanegashima Island, Kagoshima Prefecture, Japan, has been previously noted to have a marked tendency toward a short head and a flattened occipital bone, which has been suggested to be the result of artificial cranial deformation. However, whether this deformation was intentional or caused by unintentional habits remains unclear. This study aimed to investigate the characteristics of the cranial shape of the Hirota site to clarify whether the crania were intentionally modified. In the examination of Hirota crania, Kyushu Island Jomon and Doigahama Yayoi crania were added as comparative data and contrasted with three-dimensional (3D) surface scan imaging and two-dimensional outline-based geometric morphometric analysis, combined with objective assessments of potential cranial modification. The results showcased Hirota's short and flattened cranial morphology, indicating clear alignment with our hypothesis that Hirota samples are morphologically different from Doigahama and Jomon samples. No sex-based differences were found. Morphological abnormalities in cranial sutures were visually assessed utilizing novel 3D visualization methods of cranial outer surfaces. Based on a comprehensive review of the results, we concluded that Hirota site crania were intentionally modified. Although the motivation of the practice is unclear, the Hirota people may have deformed their crania to preserve group identity and possibly aid in the long-distance trade of shellfish, as seen archaeologically.

Proposing novel dorsal Proatlas-manifestations: Description and classification of three rare phenomena in humans

The craniocervical junction (CCJ) of humans and other vertebrates is a developmental restless region. Due to complex phylogenetic and ontogenetic processes, many anatomical variations can be found in that transitional area. Therefore, newly described variants must be registered, named, and classified into existing concepts explaining their genesis. This study aimed to describe and classify anatomical peculiarities that have not or rarely been reported on before in the literature. This study is based on the observation, analysis, classification, and documentation of three rare phenomena of three different human skull bases and upper cervical vertebrae, which come from the body donor program of the RWTH Aachen. As a result, three osseous phenomena (accessory ossicles, spurs, and bridges) at the CCJ of three different body donors could have been documented, measured, and interpreted. Due to extensive collecting efforts, careful maceration, and accurate observation, it is still possible to add new phenomena to the long list of Proatlas-manifestations. Further on, it could have been shown again that these manifestations can cause damage to the elements of the CCJ due to altered biomechanic conditions. Finally, we have succeeded in showing that phenomena can exist that can imitate the presence of a Proatlas-manifestation. Here, a precise differentiation between Proatlas-based supernumerary structures and the results of fibroostotic processes is necessary.

Ontogeny of the human fetal, neonatal, and infantile basioccipital bone: Traditional and extended eigenshape geometric morphometric analysis

The basioccipital bone is an essential developmental component to the occipital bone, occipital condyles, foramen magnum, clivus, and cranial base. The basioccipital bone joins each exoccipital bone with a basiexoccipital synchondrosis and the basisphenoid/sphenoid bone with a spheno-occipital synchondrosis. The basioccipital is found intermediate to the petrous temporal bones and forms the bilateral petrooccipital/petroclival fissures otherwise known as the petrooccipital complex. Thus, the basioccipital bone is a central component to the developing cranial base. Despite the importance of basioccipital development in cranial ontogeny, there has been limited study of basioccipital ontogeny. This study assessed 98 disarticulated human basioccipital bones from a perinatal population ranging in age-at-death from 5-months intrauterine to 5-months post-natal development. Size and shape of basioccipital bones were assessed with traditional and extended eigenshape geometric morphometric analysis. The results of this study demonstrate that the basioccipital bone grows in width at a faster rate than it grows in length. The maximum basioccipital width surpassed the midsagittal length at approximately 7-months intrauterine development. Canonical variate analysis revealed statistically significant shape change occurring from a relatively narrow/elongate (anterior-to-posterior) basiocciput shape with mild concavity at the foramen magnum in the fifth and sixth intrauterine months to a relatively broad/stout basiocciput shape with more pronounced concavity in the postnatal months. Likewise, growth rate in total length was greater than midsagittal length, demonstrating enlargement of concavity in the anterior foramen magnum over time. This report provides insight into cranial development and aids in estimating age-at-death among fetuses and infants.

Observational study of patients with occipital condyle fracture at a brazilian referral trauma center

OBJECTIVE

to evaluate the clinical-epidemiological characteristics, treatment, and evolution of patients with occipital condyle fracture (OCF) at one of the largest referral trauma centers in Latin America.

METHODS

this was a retrospective observational study of OCF identified from trauma cases admitted between December 2011 and December 2019 by the neurosurgery team at a Type 3 trauma center.

RESULTS

a total of twenty-eight occipital condyle fractures were identified in twenty-six patients. The incidence was less than 0.2% per year and more common in male patients (4:1 ratio) involved in traffic accidents. The mean age was 42.08 years. Anderson and Montesano type II and Tuli type 1 were the most frequent (67.9% and 89.3%, respectively) and no case presented C0-C1-C2 instability. All patients were treated with a cervical collar for 3 to 6 months. About 65% of the patients exhibited good progression (Glasgow Outcome Scale equal to 4), and the severity of traumatic brain injury was the main determinant for negative outcomes.

CONCLUSION

the findings of this study are in accordance with available literature data. The use of external stabilization with a cervical collar is reinforced for the treatment of stable lesions, even when these are bilateral. Assessment of the patients' follow-up results in the studied sample may contribute with useful information for the treatment of occipital condyle fractures.

Two-Stage Approach for Unstable Pediatric Craniocervical Junction Anomalies with a Halo Vest and Delayed Occipitocervical Fusion: Technical Note, Case Series, and Literature Review

OBJECTIVE

Malformations in the craniocervical junction (CCJ) are rare in the pediatric population but often need surgical treatment. We present a pediatric case series of patients treated with a 2-stage surgical approach with a halo vest and occipitocervical fusion and review complications and outcomes.

METHODS

A retrospective analysis of a single-center case series was performed. Pediatric patients affected by congenital craniocervical junction anomalies and treated with a 2-stage approach were included. A halo vest was implanted in the first surgery, and ambulatory progressive reduction was performed. When a favorable anatomic situation was observed, arthrodesis was performed. Safety analysis was undertaken by analyzing the incidence of complications in both procedures. Effectivity analysis was carried out analyzing radiologic and clinical outcome (Goel grade and modified Japanese Orthopaedic Association score). Student t test was used for statistical analysis.

RESULTS

Sixteen cases were included. Mean age of patients was 9.38 years. Safety analysis showed 2 halo loosenings, 1 pin infection, 2 wound infections, 1 cerebrospinal fluid leak, and 2 delayed broken rods. No major complications were observed. Radiologic analysis showed an improvement in the tip of the odontoid process to the McRae line distance (from -3.26 mm to -6.16 mm), atlantodental interval (from 3.05 mm to 1.88 mm), clival-canal angle (from 134.61° to 144.38°), and cervical kyphosis (from 6.39° to 1.54°). Clinical analysis also showed improvement in mean Goel grade (from 1.75 to 1.44) and modified Japanese Orthopaedic Association score (from 15.12 to 16.41).

CONCLUSIONS

The 2-stage approach was a suitable and effective treatment for craniocervical junction anomalies in pediatric patients.

Intraorbital, Infratemporal And Intracranial Extensions As The First Presentation Of Follicular Thyroid Carcinoma

Metastatic skull deposits from follicular thyroid carcinoma are rare, and let alone this being the primary presenting symptom with no history of thyroid cancer is exceptionally rarer. A 40-yearold female patient presented with a mass in the temporal and occipital region of the skull. Fine needle aspiration cytology confirmed multiple fragments of a neoplasm composed of variably sized follicles lined by tumour cells having pleomorphic hyperchromatic nuclei. Further workup revealed Follicular thyroid carcinoma and subsequently, total thyroidectomy was done. Skull resection was not possible due to the extensive nature of disease and patient was advised radioactive iodine ablation therapy but couldn't survive past 4 months.

« IL Profilo Istomorfologico e Istochimico del Cordoma Rinofaringeo »

3 cases of spheno-occipital chordoma with rhinopharingeal involvement have been morphologically and histochemically studied. The derivation from the notochord is stated.

Bulbar Paralysis and Facial Paralysis due to Metastatic Hepatocellular Carcinoma: A Case Report and Literature Review

Skull-base metastasis (SBM) from hepatocellular carcinoma (HCC) is extremely rare, and multiple cranial nerve paralysis due to SBM from HCC is also rare. We report a case of bulbar and facial paralysis due to SBM from HCC. A 46-year-old Chinese man presented with a hepatic right lobe lesion that was detected during a routine physical examination. After several failed attempts to treat the primary tumor and bone metastases, neurological examination revealed left VII, IX, X, and XI cranial nerve paralysis. Computed tomography of the skull base subsequently revealed a large mass that had destroyed the left occipital and temporal bones and invaded the adjacent structure. After radiotherapy (27 Gy, 9 fractions), the patient experienced relief from his pain, and the cranial nerve dysfunction regressed. However, the patient ultimately died, due to the tumor's progression. Radiotherapy is usually the best option to relieve pain and achieve regression of cranial nerve dysfunction in cases of SBM from HCC, although early treatment is needed to achieve optimal outcomes. The present case helps expand our understanding regarding this rare metastatic pathway and indicates that improved awareness of SBM in clinical practice can help facilitate timely and appropriate treatment.

[The biomechanical analysis of craniovertebral junction finite element model in atlas assimilation]

OBJECTIVE

To study the biomechanical change of the craniovertebral junction in conditions of atlas assimilation.

METHODS

Mimics software was used to process CT data of the craniovertebral junction in a health adult to obtain the three-dimensional reconstruction and the cloudy points of C1, C2 and part of the occipital bone. Then the cloudy points were imported into the Abaqus 6. 8 software to establish the occipito-atlantoaxial finite element model in normal structure. According to the established model in normal structure, the model in conditions of atlas assimilation was set by changing the model parameters. Both models of normal structure and atlas assimilation were loaded with 1. 5 N . m static moment to simulate four motions of flexion, extension, lateral bending and axial rotation respectively. The movement characteristics,joint stress force and ligament deformation was analyzed.

RESULTS

Under 1. 5 N . m moment, in model of atlas assimilation the C1-C2 range of movement decreased from 13. 55° to 11.88° in flexion,increased from 13. 22° to 15. 24° in extension and from 4. 05° to 4. 23° in lateral bending and remained unchanged in axial rotation when compared with the normal model. In flexion movement, the contact force of the atlanto-dental joint increased from 1. 59 MPa to 3. 28 MPa and the deflection of apical ligament, tectorial membrane and alar ligament increased 129. 1%, 157. 6% and 75. 1% respectively when compared with the normal model.

CONCLUSIONS

The normal C1-C2 motion mode is destructed in conditions of atlas assimilation, leading to the changes of the range of movement,joint stress force and the ligament deformation at C1 C2 junction. The atlantoaxial instability will likely occur in flexion motion.

Embryology, classification, and surgical management of bony malformations of the craniovertebral junction

The embryology of the bony craniovertebral junction (CVJ) is reviewed with the purpose of explaining the genesis and unusual configurations of the numerous congenital malformations in this region. Functionally, the bony CVJ can be divided into a central pillar consisting of the basiocciput and dental pivot; and a two-tiered ring revolving round the central pivot, comprising the foramen magnum rim and occipital condyles above, and the atlantal ring below. Embryologically, the central pillar and the surrounding rings descend from different primordia, and accordingly, developmental anomalies at the CVJ can also be segregated into those affecting the central pillar and the surrounding rings, respectively. A logical classification of this seemingly unwieldy group of malformations is thus possible based on their ontogenetic lineage, morbid anatomy, and clinical relevance. Representative examples of the main constituents of this classification scheme are given, and their surgical treatments are selectively discussed.

[Cerebellar abscesses secondary to infection of an occipital dermal sinus]

A dermal sinus is a congenital defect arising from a closure failure of the neural tube that results in different degrees of communication between the skin and the central nervous system. A dermal sinus can occur anywhere from the root of the nose to the conus medullaris, and the occipital location is the second most common. Dermal sinuses are often found in association with dermoid or epidermoid cysts and less frequently with teratomas. Patients with an occipital dermoid cyst associated with a dermal sinus can develop meningitis and/or abscesses as the first clinical manifestation of the disease due to the dermoid cyst itself becoming abscessed or to the formation of secondary abscesses; few cases of the formation of secondary abscesses have been reported. We present a case of a dermoid cyst associated with an infected dermal sinus and posterior development of cerebellar abscesses and hydrocephalus.

[Operative neurosurgery: personal view and historical backgrounds (8) suboccipital craniotomy-sitting position-linear incision]

Suboccipital craniotomy (SOC) can be classified into three types: midline, paramedian and lateral according to the site of linear incision. They are subdivided horizontally into cranial, intermediate and caudal, while the latter of the lateral SOC should be included into the paramedian caudal one (Fig. 1, 19). Sitting position for the craniotomy has several advantages over other positionings in spite of several known drawbacks especially air embolism: cleanliness of the operative field, good anatomical orientation, wider operative spaces obtained by gravitational downward displacement of the cerebellar hemisphere above all. Linear incision is considered to have no definite drawbacks as compared with other incisions such as the horse shoe or the hockey-stick incision and rather have advantages such as enabling effective access to the surgical target by the use of navigation, simpleness of craniotomy in the opening and the closure, and less pseudomeningocele complication. Although cranial and intermediate lateral SOCs are mainly for lesions in the upper and middle CP angle such as acoustic neurinomas or meningioma besides MVD for trigeminal neuralgia, these are applied also for cavernomas of the tectal and cerebellar peduncle, and meningiomas or chordomas of the upper and middle 1/3 of the petroclival region (Fig. 2-5). Importance of the SCTTA by cranial paramedian SOC for the management of lesions in the temporoposteromedial region including the tentorium and its incisura was emphasized and peduncular lesions at the lamina tecti and pons as well. Caudal paramedian SOC is appropriate for lesions in the lower CP angle along with MVD for hemifacial spasm and is furthermore applicable for foramen magnum meningiomas or lower clivus meningiomas by TVDRA (Fig. 6-13). Cranial midline SOC (paraculminar approach) is applicable for tumors of pineal regions and for lesions at the midbrain, thalamus, posterior part of the IIIrd ventricle. The TFUTA by lower midline SOC enables simple access to the IV ventricle and its floor for management of lesions at the tegmentum pontis such as cavernomas (Fig. 14-17). Statistics of a series of consecutive 1,573 surgical cases in the sitting position (1994-2003) are presented including detection rate of air embolism on the anesthetic charts (Fig. 18, Table). Air embolism was most frequent (21%) in the lateral SOC as compared with other SOCs (8.8% on the average). This happened during the extradural procedures in 80% and in 20% in the intradural procedures. Some important technical managements of bridging veins, venous plexus and cerebellar retraction are discussed in carrying out the SOCs.

Conditioned pain modulation evoked by different intensities of mechanical stimuli applied to the craniofacial region in healthy men and women

AIMS

To investigate systematically whether conditioned pain modulation (CPM) evoked by tonic mechanical stimuli applied to the craniofacial region is intensity-, assessment site-, and gender-dependent.

METHODS

Twenty healthy men and 20 women participated in four sessions. Tonic painful mechanical stimulation was applied to pericranial muscles by a mechanical headband pressure device. The pressures applied to four probes were adjusted via pain feedback from a 0 to 10 electronic visual analog scale (VAS) to generate different pain levels (VAS0, VAS1, VAS3, or VAS5) for 10 minutes. Pressure pain thresholds (PPTs) and pressure pain tolerance thresholds (PPTols) were assessed from right masseter muscle and left forearm by pressure algometry before, during, immediately after, 10 minutes after, and 20 minutes after the conditioning stimulus (CS). Data were analyzed with multilevel ANOVAs.

RESULTS

PPT values normalized to baseline recordings were not dependent on gender or assessment site, but dependent on intensity (P < .001) and time (P < .001). The most painful CS (VAS5) was associated with the highest PPT increases (32.6% ± 3.3%, mean value for the two assessment sites and two genders) during CS compared to all other intensities of CS (P < .001). PPTol values normalized to baseline recordings were also not dependent on gender or assessment site, but dependent on intensity (P < .001) and time (P < .001). The most painful CS (VAS5) was associated with higher PPTol increases (11.2% ± 2.8%, mean value for the two assessment sites and two genders) during CS (P < .001).

CONCLUSION

CPM evoked by mechanical stimulation of the craniofacial region is intensity-dependent but not assessment site- or gender-dependent.

Occipital neuralgia: possible failure of surgical treatment - case report

Surgical intervention in severe cases of occipital neuralgia should be considered if pharmacological and local nerve blocking treatment fail. The literature suggests two types of interventions: surgical decompression of the greater occipital nerve (GON) from the entrapment site, as a less invasive approach, and neurotomy of the nerve trunk, which results in ipsilateral sensation deficits in the GON innervated area of the skull. Due to anatomical variations in the division of the GON trunk, typical neurotomy above the line of the trapezius muscle aponeurosis (TMA) may not result in full recovery. The present study discusses a case of a female treated with GON decompression as a result of occipital neuralgia unresponsive to pharmacotherapy, who thereafter was qualified for two consecutive neurotomies due to severe relapse of pain.

[Fibrous dysplasia involving sphenoid and occipital bone: one case report and literature review]

OBJECTIVE

To study the clinical manifestation, radiograph features, pathology, diagnosis and treatment of fibrous dysplasia in cranial bone.

METHOD

A case of fibrous dysplasia involving sphenoid and occipital is reported and literature were reviewed.

RESULT

The most common complaint were headache, proptosis, diplopia, or visual changes. Distinguishing features of fibrous dysplasia on CT include "ground-glass" appearance, bone fiber anisotrophy, aneurysmal bone cyst formation and thickness of the cranial cortices. Fibrous dysplasia could be exactly diagnosed by pathology. Computed tomography was also a choice for diagnosis.

CONCLUSION

Fibrous dysplasia involving the cranial bone can present in myriad ways. Modern imaging modalities and histopathologic analysis is required to make accurate diagnosis. Surgery, particularly in a challenging region such as sphenoid and occipital bone, should preserve the existing function for the patients with functional impairment or a cosmetic deformity.

Meningiomas of the falcotentorial junction: selection of the surgical approach according to the tumor type

BACKGROUND

We retrospectively analyzed a series of patients harboring a FT meningioma with regard to clinical presentation, surgical technique, and follow-up results.

METHODS

Clinical data in a consecutive series of 13 patients treated for a meningioma of the FT junction were retrospectively reviewed. Tumors were classified into 4 types according to their dural origin and tumor extent as depicted from preoperative MRI.

RESULTS

Main presenting symptom in 9 women and 4 men (mean age, 56 years) was headache (69%) and gait disturbance (54%). Clinical examination revealed gait ataxia in 62% of the patients. The tumor displaced the vein of Galen inferiorly in 6 patients, superiorly in 2, and medially in 5 cases. The main surgical approach to the meningioma was via an occipital interhemispheric route (10 patients). Additional resection of the falx and/or incision of the tentorium was performed in 6 cases each. A complete resection (Simpson grade 1 and 2) was achieved in 85% of patients. Permanent surgical morbidity was 23%. One tumor recurrence in an atypical meningioma was observed after the mean follow-up period of 6.2 years (range, 1-14 years) with clinical and MRI examination and had to be reoperated. Eighty-five percent of the patients regained full daily activity on follow-up.

CONCLUSIONS

The surgical approach should be tailored to the dural origin and extent of the tumor as depicted from preoperative MRI. Preservation of the straight sinus and Galenic venous system is recommended.

The occipital and sacral pressures experienced by healthy volunteers under spinal immobilization: a trial of three surfaces

BACKGROUND

The development of a pressure ulcer is of great significance to the life-long rehabilitative management of the person with a spinal cord injury, and may indeed delay and repeatedly interfere with that process. That the period preceding admission to the specialized spinal injury unit is crucial with regard to pressure ulcer development is evident in the professional literature. Both anecdotal and empirical evidence indicates that a significant number of pressure ulcers occur as a result of management provided prior to admission, and that such ulcers are more likely to occur in those patients who have undergone a transfer process from a hospital distal to the specialist unit on a hard spinal board.

AIM

In consideration of this and of the fact that, in Ireland, the interhospital transfer of spinal injured patients has usually involved the employment of such spinal boards to achieve immobilization, this study sought to identify whether or not the pressure experienced by individuals at two anatomical locations was dependent on the support surface employed.

METHODOLOGY

Pressure under the occiput and sacrum of three healthy volunteers immobilized on three support surfaces was measured using air-filled pressure-measuring sacks. The surfaces employed were an uncovered spinal board; a spinal board with inflatable raft devise; and a full-body vacuum splint.

DISCUSSION

Marked reductions in pressure were measured when using the inflatable raft and the vacuum mattress. The results of this study will provide a basis for a larger study and, through that, the formulation of recommendations for standardized practice along a national care pathway.

A kinematic and anthropometric study of the upper cervical spine and the occipital condyles

The center of rotation (COR) of the upper cervical spine (UCS) is an important biomechanical landmark that is used to determine upper neck moment, particularly when evaluating injury risk in the automotive environment. However, neither the location of the UCS CORs nor the occipital condyles (OCs), which are frequently the referenced landmark for UCS CORs, have been measured with respect to known cranial landmarks. This study determines the CORs using pure bending (+/-3.5 N m), 3D digitization, and image analysis. Landmarks digitized included the OCs, external auditory meatus (EAM), infraorbital foramen, zygion, nasion, and the foramen magnum. The centroid of each occipital condylar surface (area 301+/-29.8 mm(2); length 25.4+/-3.2 mm) was located 18.4 mm posterior, 54.4 mm medial, and 31.0 mm inferior of the EAM. The UCS CORs were distinct: On average, OC-C1 CORs (22.5 mm posterior and 22.6 mm inferior to the left EAM) were superior and more posterior of OCs; C1-C2 CORs (7.4 mm posterior and 46.7 mm inferior to the left EAM) were inferior and more anterior of OC; and OC-C2 CORs (17.0 mm posterior and 33.1 mm inferior to the left EAM) were aligned with OC. There was a statistically significant difference between the percentage of UCS rotation in C1-C2 and OC-C1; 45% of the flexion and 71% of the extension occurred in OC-C1. Details of an anatomical variant with two pairs of distinct condylar surfaces are also presented.

Jugular foramen meningocoele in a patient with neurofibromatosis type 1

Objective:

We present a rare case of a jugular foramen meningocoele in a 48-year-old female, with neurofibromatosis type 1, presenting with positional vertigo. We also postulate possible underlying pathophysiological mechanisms.

Method:

We describe the imaging findings of this rare entity and review the literature on skull base meningocoeles, particularly in the context of neurofibromatosis type 1.

Results:

A computed tomography scan revealed smooth expansion of the jugular foramen. Magnetic resonance imaging showed a fluid filled lesion expanding the jugular foramen and communicating with cerebrospinal fluid of the cerebellomedullary cistern superiorly.

Conclusion:

Skull base meningocoeles are a rare entity and we believe that this is the first reported case of a meningocoele causing enlargement of the jugular foramen in a patient with neurofibromatosis type 1. The meningocoele may have resulted from a severe form of dural ectasia or from dysplastic, weakened bone at the skull base.

Bilateral parieto-occipital dermoid sinuses in a Rottweiler

Bilateral dermoid sinuses were identified on the parieto-occipital region of a Rottweiler. Diagnosis was confirmed by histological examination after successful complete surgical resection. The dermoid sinuses were independent with separate tracts. This unusual parasagittal location can be explained by craniofacial development: dermoid sinuses on the head could occur along the lines of embryological fusion and not only in the sagittal plane. A hypothesis of an origin at the level of the suture between the parietal and interparietal bones is possible in this case.

Temporary alopecia after subarachnoid haemorrhage

Primary endovascular intervention is increasingly the first choice of treatment for cerebral aneurysms, particularly for those with complex anatomy in the posterior circulation. However, their clinical management and follow-up continue to be predominantly in the hands of neurosurgeons. In this report, the development of alopecia following the coiling of posterior circulation aneurysms is described. The alopecia was transient and lasted for approximately 6 months, and occurred in the occipital and suboccipital regions of the scalp. This report aims to highlight this condition, which has not been previously reported in the neurosurgical literature. The potential hazards of irradiation should be borne in mind while carrying out complex endovascular procedures. The patient should be counselled and all necessary steps undertaken to limit radiation exposure.

A Case of Pulsed Radiofrequency Lesioning for Occipital Neuralgia: Table 1

OBJECTIVE

This report describes a case where pulsed radiofrequency lesioning (RFL) of the greater occipital nerve (GON) offered a valuable and safe treatment for the management of greater occipital neuralgia. The case is considered in relation to a review of the medical literature on greater occipital neuralgia and RFL interventions.

CASE REPORT

A 62-year-old man with a 43-year history of left suboccipital pain underwent pulsed RFL of the left GON (20-millisecond bursts at intervals of 0.5 second for 4 minutes at 42 degrees C) after failing to achieve substantial analgesia with naproxen, a transcutaneous electrical nerve stimulator (TENS) unit and a greater occipital nerve blockade (GONB) utilizing local anesthetic and steroid. After obtaining 4 months of 70% pain relief, pulsed RFL was repeated and resulted in an additional 5 months of 70% pain relief.

CONCLUSIONS

Pulsed RFL of the GON is an alternative to continuous RFL with the proposed advantage of mitigating pain, as in continuous RFL, but without the potential risk of causing deafferentation pain. While placebo and other nonspecific analgesic effects cannot be ruled out, the apparent safety profile and potential efficacy of pulsed RFL suggests it may be a compelling option to consider before irreversible neuroablative therapies are applied.

Occipital condyle syndrome guiding diagnosis to metastatic prostate cancer

Occipital condyle syndrome (OCS) results from a unilateral occipital pain associated with an ipsilateral paresis of the 12th cranial nerve (hypoglossal), and is typically caused by metastasis of the skull base. OCS diagnosis occurred, in all cases described in the published literature, when metastatic prostate cancer (MPC) was previously known. We present a case of a patient whose initial manifestation of MPC was OCS. The patient was treated with complete hormonal blockade and non-steroidal anti-inflammatory drugs as opposed to locoregional radiotherapy applied in other cases. After 18 month follow-up, the patient had a complete neurological and biochemical response.

Functional connectivity between trigeminal and occipital nerves revealed by occipital nerve blockade and nociceptive blink reflexes

Headache syndromes often suggest occipital and neck involvement, although it is still unknown to what extent branches of segment C1-C3 contribute actively to primary headache. Pain within the occipital area may be referred to the trigeminal territory. However, a modulation of trigeminal transmission by affecting cervical input in humans has not been elucidated so far. A convergence of cervical and trigeminal input at the level of the caudal part of the trigeminal nucleus in the brainstem has been suggested due to anatomical and neurophysiological studies in animals. We examined the R2 components of the nociceptive blink reflex responses in 15 healthy subjects before and after unilateral nerve blockade of the greater occipital nerve with 5 ml prilocain (1%). R2 response areas (AUC) decreased and the R2 latencies increased significantly after the nerve blockade only on the side of injection. AUC and latencies on the non-injection side remained stable. Thresholds for sensory or pain perception did not differ significantly between the repeated measurements on both sides. Our findings extend previous results related to anatomical and functional convergence of trigeminal and cervical afferent pathways in animals and suggest that the modulation of this pathway is of potential benefit in primary headache disorders.

Anatomical study of the occipital sinus using contrast-enhanced magnetic resonance venography

The frequency and anatomical features of the occipital sinus (OS) were analyzed in this study by contrast-enhanced magnetic resonance venography (MRV) with enhanced fast gradient echo three-dimensional (EFGRE3D) and we discuss the clinical usefulness of this method. The study included 555 patients who underwent contrast-enhanced MRV with EFGRE3D, and maximum intensity projection (MIP), multiplanar reformation (MPR) and multiprojection volume reconstruction (MPVR) images were obtained for the regions of interest. The frequency, size and communication of the OS with other vessels were assessed. The OS was identified in 209 of the 555 patients (37.7%). There were no statistically significant sex-related differences. The OS was observed less frequently in subjects younger than 50 years. Cranially and/or caudally, some OS were separated and communicated with multiple vessels. In five patients, the straight sinus (StS) communicated directly with the OS and not with the other sinuses; in two patients, the StS communicated with veins other than the OS only via small anastomotic veins. Many morphological differences in the OS can be seen. In addition, some OS function as the main drainage route of the intracranial veins instead of the transverse sinus or sigmoid sinus. In addition to MIP, detailed examination by MPR and MPVR is required for the preoperative evaluation of posterior cranial fossa lesions.

[Coarctation of the aorta presenting as a pulsatile occipital mass]

A healthy 18 months old boy, is referred to our hospital for a thrilling pulsatile mass behind the left ear. Aortography in the ascending aorta shows a severe coarctation with almost interruption of the aorta between the left carotid and left subclavian artery. Both external carotid arteries provide an important collateral pathway through occipital arteries to two dilated vertebral arteries. Descending aorta is feeding by a reverse blood flow into vertebral and subclavian arteries. The child has been operated. This is an original presentation of severe coarctation of the aorta with development of an important and vital collateral pathway.

Development and rapid growth of a desmoid tumor in the surgical corridor after suboccipital craniotomy for recurrent low-grade astrocytoma

Desmoid tumors are histologically benign but locally invasive tumors that can occur in the head and neck. We present the rare case of a desmoid tumor that occurred in the surgical corridor after suboccipital craniotomy for recurrent low-grade astrocytoma. A 30-year-old woman underwent a repeat suboccipital craniotomy for recurrent low-grade astrocytoma. A gross total resection was achieved. Nine months later, a firm, palpable mass was noted near the surgical scar. No new neurologic deficits were noted on exam. A magnetic resonance imaging scan demonstrated a homogeneously enhancing lesion superficial to the dural graft. Surgical resection of the lesion was performed through the original midline incision. The mass was resected en bloc. Histology demonstrated clear surgical margins and a tumor of low cellularity consistent with a desmoid tumor. Desmoid tumors should be considered in the differential diagnosis for superficial masses occurring in the surgical bed after posterior cervical surgery.

Prenatal diagnosis of occipital dermal sinus associated with hemangioma using ultrasound and MRI. Case report

OBJECTIVE

We report a case of prenatal diagnosis and postpartum management of a subcutaneous tumor without intracranial communication.

METHODS

An occipital tumor without intracranial communication was found on ultrasound scan in the 21st week of pregnancy. Using MRI, the diagnosis was confirmed. Subcutaneous localization of the tumor was verified and communication with intracranial space excluded.

RESULTS

The newborn was delivered spontaneously at term and underwent a successful surgical procedure 5 months postpartum.

CONCLUSION

The prenatal diagnosis allowed differentiation between a communicating neural tube defect with poor prognosis, and a manageable extracranial subcutaneous tumor. The precise diagnosis of uncomplicated dermal sinus was possible only after the histological evaluation of the tumor confirmed occipital dermal sinus associated with hemangioma.

Radiation-Induced Osteosarcoma 16 Years After Surgery and Radiation for Glioma-Case Report-

A 35-year-old man developed osteosarcoma of the left parietal and occipital bones 16 years after radiotherapy for glioma in the right occipital lobe. Radiotherapy of the primary neoplasm used 50 Gy administered to a localized field through two lateral ports. The secondary neoplasm arose contralateral to the primary lesion but within the irradiated field. The tumor had a multilocular cyst with considerable intracranial extension, and symptoms of elevated intracranial pressure were prominent early in the course. After a short-lived initial remission following surgical intervention and chemotherapy, the patient deteriorated because of tumor recurrence and died 18 months after the diagnosis. Radiation-induced osteosarcoma is a well-known but rare complication of radiotherapy for brain neoplasms with a poor prognosis.

[Fibrous dysplasia of bone in a 12-year old girl]

Fibrous dysplasia of bone is a rare congenital bone disease, usually coming out before the age of 30. It is 2.5% of all bone tumours and 7.5 % of benign tumours of bones. The authors present a case of a 12-years old girl with fibrous dysplasia of bone admitted to the Department with hyperparathyroidism suspicion. Pathological changes were localized in the orbital cavity and sinuses. The diagnosis was established on the basis of the clinical course, imaging and histopathological examinations. The therapy with pamidronian acid was applied.

Differentiating imaging findings in primary and secondary tumors of the jugular foramen

The preoperative diagnosis of a jugular foramen tumor may be challenging, since a large variety of unusual lesions may be located in this region. These tumors may be classified as primary lesions (which are located in the jugular foramen or extend from the jugular foramen into the surrounding structures) and as secondary lesions (that extend from the surrounding structures into the jugular foramen). Primary tumors include glomus jugulare tumors, schwannomas, meningiomas and peripheral primitive neuroectodermal tumors, while secondary tumors comprise chordomas, chondrosarcomas, chondroblastomas, giant-cell tumors, cholesterol granulomas, giant cholesterol cyst, endolymphatic sac tumors, reactive myofibroblastic tumors, temporal bone carcinomas and metastases. Accurate preoperative radiological suspicion is of great value for preoperative patient counseling and has a direct impact on the surgical planning in these cases. The present study describes and discusses the main differentiating imaging features of lesions involving the jugular foramen, whose accurate preoperative radiological evaluation is essential for proper surgical planning.