Skull Base Abnormalities Research Articles

Cranial base abnormalities in osteogenesis imperfecta: Phenotypic and genotypic determinants

Cranial base abnormalities are an important complication of osteogenesis imperfecta (OI), a hereditary bone fragility disorder that in most patients is caused by mutations affecting collagen type I. To elucidate which clinical characteristics are associated with the occurrence of cranial base abnormalities in OI, we compared cephalometric results of 187 OI patients (median age 12.0 years, range 3.4 to 47 years; 96 female) with those of 191 healthy subjects and related findings to clinical descriptors of the disease. Overall, 41 patients (22%) had at least one unambiguously abnormal skull base measure. Multivariate logistic regression analysis in patients with OI types I, III, and IV (n = 169) revealed that height Z-score [odds ratio (OR) = 0.53, 95% confidence interval (CI) 0.43-0.66, p < .001]--but not age, gender, scleral hue, lumbar spine areal bone mineral density, or a history of bisphosphonate treatment--was a significant independent determinant of skull base abnormalities. Among patients with a height Z-score below -3, 48% had a skull base abnormality regardless of whether they had received bisphosphonate treatment in the first year of life or not. Genotype-phenotype correlations were evaluated in patients with detectable mutations in COL1A1 or COL1A2, the genes coding for collagen type I (n = 140). Skull base abnormalities were present in 6% of patients with haploinsufficiency (frameshift or nonsense) mutations, in 43% of patients with helical glycine substitutions caused by COL1A1 mutations, in 32% of patients with helical glycine substitutions owing to COL1A2 mutations, and in 17% of patients with splice-site mutations affecting either COL1A1 or COL1A2. However, multivariate logistic regression analysis showed that height Z-score but not the type of collagen type I mutation was independently associated with the prevalence of skull base abnormalities. In conclusion, this study shows that clinical severity of OI, as expressed by the height Z-score, was the strongest predictor of skull base abnormalities. We did not find evidence for the hypothesis that bisphosphonate treatment protects against skull base abnormalities.

Carpenter Syndrome

Carpenter syndrome is a rare autosomal recessive disorder that belongs to a group of rare craniosynostosis syndromes (Bull Soc Med Paris 1906;23:1310). Carpenter syndrome is the rarest, with only occasional patients seen. There are 3 common features in all of these syndromes: craniosynostosis (skull base abnormalities, with early fusion in different sutures), midface hypoplasia, and musculoskeletal abnormalities. Clinical features of Carpenter syndrome include peculiar facies, asymmetry of the skull, polydactyly, brachymesophalangy, mild soft tissue syndactyly, obesity, hypogenitalism, congenital heart disease, and mental retardation (J Pediatr 1966;69:1; Am J Roentgenol 1969;106). The brachycephaly is caused by early fusion in the coronal, sagittal, and lambdoidal sutures (Proc R Soc Med Sect Study Dis Child 1909). Most of the affected patients have a surgical procedure between 3 to 9 months of age to open the cranial vault to make space for the brain to grow (Plast Reconstr Surg 1978;62:335). We present a patient with Carpenter syndrome who is unusual in that she is an adult who has never had surgical intervention.

Artificial atlanto-odontoid joint replacement through a transoral approach

Resection of the odontoid process and anterior arch of the atlas results in atlantoaxial instability, which if left uncorrected may lead to severe neurological complications. Currently, such atlantoaxial instability is corrected by anterior and/or posterior C1-C2 fusion. However, this results in considerable loss of rotation function of the atlantoaxial complex. From the viewpoint of retaining the rotation function and providing stability, we designed an artificial atlanto-odontoid joint based on anatomical measurements of 50 pairs of dry atlantoaxial specimens by digital calipers and 10 fresh cadaveric specimens by microsurgical techniques. The metal-on-metal titanium alloy joint has an arc-shaped atlas component, and a hollow cylindrical bushing into which fits a rotation axle of an inverted v-shaped axis component and is implanted through a transoral approach. After the joint was implanted onto specimens with anterior decompression, biomechanical tests were performed to compare the stability parameters in the intact state, after decompression, after artificial joint replacement, and after fatigue test. Compared to the intact state, artificial joint replacement resulted in a significant decrease in the range of motion (ROM) and neutral zone (NZ) during flexion, extension, and lateral bending (P < 0.001); however, with regard to axial rotation, there was no significant difference in ROM (P = 0.405), a significant increase in NZ (P = 0.008), and a significant decrease in stiffness (P = 0.003). Compared to the decompressed state, artificial joint replacement resulted in a significantly decreased ROM (P B 0.021) and NZ (P B 0.002) and a significantly increased stiffness (P \ 0.001) in all directions. Following artificial joint replacement, there was no significant difference in ROM (P C 0.719), NZ (P C 0.580), and stiffness (P C 0.602) in all directions before and after the fatigue test. The artificial joint showed no signs of wear and tear after the fatigue test. This artificial atlanto-odontoid joint may be useful in cases of odontoid resection due to malunion or nonunion of odontoid fracture, atraumatic odontoid fracture, irreducible atlas dislocation, posterior atlantoaxial subluxation, or congenital skull base abnormalities.

Skull base abnormalities in osteogenesis imperfecta: a cephalometric evaluation of 54 patients and 108 control volunteers

Osteogenesis imperfecta (OI), which usually results from mutations in type I collagen genes, causes bone fragility and deformities. The head is often abnormally shaped, and changes in skull base anatomy in the form of basilar impression and basilar invagination have been reported. The authors analyzed the skull base anatomy on standardized lateral cephalograms from 54 patients with OI (Types I, III, and IV) and 108 control volunteers. They were surprised to find that the previously used diagnostic measures for basilar abnormality in patients with OI were exceeded in 6.5 to 7.4% of the controls, and hence needed to be reevaluated. The authors calculated the distance from the odontoid process to four reference lines, including a novel one, in the controls. The normal mean distances were exceeded by more than two standard deviations (SDs) in 28.3 to 35.2%, and by more than three SDs in 13.2 to 16.6% of the patients with OI. The latter figures reliably reflect the prevalence of basilar impression. As a sign of basilar invagination the odontoid process protruded into the foramen magnum or reached the foramen magnum level in 22.2% of the patients with OI, whereas none of the controls showed this feature. Platybasia (an anterior cranial base angle > 146 degrees) was present in 11.1% of the patients but in none of the controls. Platybasia, basilar impression, and basilar invagination were often coexpressed, but each was also present as an isolated abnormality. These three abnormalities and wormian bones were predominantly found in OI Types III and IV as well as in patients exhibiting dentinal abnormality.

Ostéomyélite de l’étage moyen de la base du crâne d’origine sinusienne

The study goals were to determine the patient demographics, identify predisposing factors, and determine efficacy of treatment for nonotologic osteomyelitis of the middle skull base. Symptoms and treatment of five patients (sex ratio: 3/1; mean age: 57,1 ans) with osteomyelitis of the middle skull base treated from 1991 to 2005 are analyzed. All patients with a biopsy-proven diagnosis of osteomyelitis of the skull base were retrospectively evaluated. Four patients presented with asthenia, weight loss, headache, and fever. No patient presented with neurologic deficits associated with a destructive lesion of the osseous skull base. Three patients had an underlying immunocompromising condition (diabetes mellitus, steroid and immunosuppressor use). CT scan and MRI demonstrated central skull base abnormality, mainly at the level of the clivus. Systemic antibacterial/antifungal therapy, aggressive debridement of involved bone, and medical optimization remain important in the treatment of this group of patients. The interpretation of the results is performed after an analysis of the literature.

Staging of nasopharyngeal carcinoma investigated by magnetic resonance imaging

Background and purposeTo investigate the American Joint Commission on Cancer (AJCC) sixth edition staging system of nasopharyngeal carcinoma (NPC) by Magnetic Resonance Imaging (MRI). Patients and methodsOne hundred and fifty-nine non-disseminated biopsy-proven NPC patients were studied with MRI before treatment. Retrieval of MRI information enabled us to restage all patients accurately according to the sixth edition of the AJCC staging system. Splitting the respective T and N stages by the significant defining factors identified, the cancer death hazard ratios were modeled by the Cox model in SPSS 10.0 for windows (SPSS Inc, Chicago, IL). ResultsSingle site of skull base abnormality (HR=3.91, 95% CI: 0.74–20.56) has a superior result to others involved in T3 (HR=5.83, 95% CI: 1.24–27.29). Involvement of either anterior or posterior cranial nerves solely (HR=6.02, 95% CI: 1.55–35.60) was not found to be as a poor prognostic indicator as others involved in T4 (HR=7.81, 95% CI: 1.81–33.63). Less than or equal to 3cm of N1 (HR=4.01, 95% CI: 0.48–33.83) and N2 (HR=4.72, 95% CI: 0.62–35.78) have a better result than >3cm of N1 (HR=8.09, 95% CI: 0.95–68.97) and N2 (HR=10.58, 95% CI: 1.32–84.62), respectively. ConclusionsPerhaps, it is better to down-stage single site of skull base abnormality from T3 to T2, and involvement of either anterior or posterior cranial nerves solely from T4 to T3, meanwhile, ≤3cm of N2 down-stage to N1, >3cm of N1 up-stage to N2.

Meningeoma de goteira olfatória: relação entre achados clínico-radiológicos e índice proliferativo (Mib-1)

The aim of this study is to correlationate demographic, radiologic features and proliferative index defined by immunohistochemical expression of Mib-1 in olfactory groove meningiomas, and to observe possible predictive factors of recurrence of this tumor. There were analysed demographic, clinical and radiological features of 15 patients with olfactory groove meningioma. Fifteen paraffin-embebed tumors were studied by immunohistochemical methods for the expression of proliferative index by the Mib-1. There was a statistically positive correlation between tumoral and edema volumes. There was no correlation between Mib-1, tumoral volume, tumoral edema and frontal skull base abnormalities. Two cases with tumor recurrence had proliferative indices higher than the mean index. Larger tumors were more susceptible to develop peritumoral edema. The proliferative índex has no positive correlation with tumoral volume, edema volumes and skull base invasion, but probably it is associated with tumoral recurrence.

Sclerosis of the Pterygoid Process in Untreated Patients with Nasopharyngeal Carcinoma

To retrospectively evaluate the prevalence of pterygoid process sclerosis in patients with untreated nasopharyngeal carcinoma. This retrospective HIPAA-compliant study was performed after the institutional review board deemed it to be exempt from review and patient informed consent. Contrast material-enhanced computed tomographic (CT) scans of the neck obtained in 31 patients (22 men, nine women; mean age, 42 years; age range, 27-68 years) with untreated nasopharyngeal carcinoma and in 31 control subjects (17 men, 14 women; mean age, 43 years; age range, 19-62 years) were evaluated independently by two neuroradiologists. The presence of sclerosis of the pterygoid process-defined as increased attenuation in the medullary cavity and/or thickening of the cortical bone-was assessed. Other findings noted included pterygoid process erosion, enhancing tumor adjacent to the pterygoid process, and CT evidence of parapharyngeal extension of the tumor. The data were evaluated by using generalized estimating equations based on a binary logistic regression model. The prevalence of pterygoid process sclerosis averaged for the two readers was 60% (37 of 62 subjects) among the patients with nasopharyngeal carcinoma but only 3% (two of 62 subjects) among the control subjects, indicating a highly significantly increased prevalence (P < .001) of this finding in the patients with nasopharyngeal carcinoma. The overall prevalences of pterygoid process erosion, parapharyngeal extension of tumor, and enhancing tumor adjacent to the pterygoid process were 27% (17 of 62 subjects), 47% (29 of 62 subjects), and 77% (48 of 62 subjects), respectively. Pterygoid process sclerosis was the sole skull base abnormality in 36% (11 of 31) of the patients with nasopharyngeal carcinoma. Sclerosis of the pterygoid process, which was present in about half of the patients with untreated nasopharyngeal carcinoma, may reflect tumor proximity to or tumor invasion of the pterygoid process.

Chronic rhinosinusitis in congenital craniofacial malformations

To review developmental abnormalities and iatrogenic alterations in sinus anatomy that may predispose patients with congenital craniofacial malformations to chronic rhinosinusitis. Retrospective study. Seven patients with craniofacial malformations who were surgically treated by the senior author were included in the study. All were diagnosed with chronic rhinosinusitis refractory to medical management. Four patients had undergone previous corrective craniofacial surgery, and three of these patients developed iatrogenic sinus disease. Demographic data, diagnoses and anatomical abnormalities were included. Abnormal sinus anatomy was present in all patients, most commonly skull base abnormalities and dehiscent lamina papyracea. All patients underwent successful endoscopic surgical management (n = 7) for their chronic rhinosinusitis. Two patients had adjuvant external procedures. There were no complications and no recurrences after a mean follow up time of 15 months. Otolaryngologists should be aware of the possibility of chronic rhinosinusitis in patients with craniofacial malformations. Careful preoperative evaluation of radiographic studies should be performed as most of these patients will have abnormal sinus anatomy. In addition, patients who undergo surgery to correct their craniofacial malformations are susceptible to altered sinus anatomy that may predispose them to the development of iatrogenic chronic rhinosinusitis.

Three-dimensional computed tomography of congenital nasal anomalies

Objective: To determine the utility of performing three-dimensional (3D) computed tomography (CT) of congenital naso-frontal anomalies for preoperative planning and counseling and compare it with standard two-dimensional (2D) imaging and intraoperative findings. Study Design: Prospective case evaluation of imaging studies and medical records in cohort of patients with congenital nasal anomalies. Methods: We performed 3D CT imaging of three different types of congenital nasal lesions. Additional preoperative imaging consisted of standard 2D CT scans and/or magnetic resonance imaging (MRI). Information obtained from the 3D CTs was compared with other standard imaging and intraoperative findings. Results: 3D CT was most useful in the case of a large encephalocele with a significant bony defect of the anterior cranial fossa. It provided moderate utility when used to evaluate a nasal dermoid with nasal bone and septal abnormalities and was of limited benefit in the case of a bifid nose with significant external soft tissue deformity and relatively normal bony anatomy. Conclusion: Congenital midline nasal anomalies are rare lesions with the potential for intracranial extension and anterior skull base abnormalities. The safe surgical treatment of these lesions depends upon accurate preoperative imaging to assist in establishing the diagnosis, to help guide surgical planning, and to assist in communicating the diagnosis and surgical approach for optimal counseling of families. 3D CT was instrumental in providing additional useful information in cases with significant bony abnormalities at little additional cost or time. It is also beneficial for preoperative counseling of patients and families with limited medical knowledge.

Central skull base invasion of maxillofacial tumors: Computed tomography appearance

The aim of this study was to demonstrate computed tomography (CT) features of maxillofacial tumors invading the central skull base and to offer information in aiding diagnosis. Fifty-eight maxillofacial tumors with central skull base invasion shown on axial and coronal CT images were divided into benign (13 cases) and malignant (45 cases) groups, based on their pathologic outcomes as proven by biopsy and surgery. Four manifestations of the skull base abnormality were observed on CT images: (1) resorption of central skull base (53 cases, 11 benign and 42 malignant tumors); (2) enlargement of the foramen and canal in the central skull base (20 cases, 4 benign and 16 malignant tumors); (3) thinning of the central skull base (11 cases, 8 benign and 3 malignant tumors); and (4) displacement of the central skull base (5 cases, all benign tumors). The following structures of the central skull base were involved: the roof of the pterygoid process of the sphenoid bone (49 cases), the sphenoid greater wing (37 cases), the sphenoid body and sinus (33 cases), the petrous apex (12 cases), the clivus (4 cases), and the articular surface of the temporal squama (3 cases). Of 58 patients, 30 (7 benign and 23 malignant) had tumors with central skull base erosion that infiltrated into the cranial cavity. Benign maxillofacial tumors with center skull base erosion tended to lead to the displacement and thinning of the base of the middle skull fossa in contrast with tumors with malignant maxillofacial tumors. It is believed that these CT manifestations might be valuable in making a differential diagnosis.

Normal Development of Sutures and Synchondroses in the Central Skull Base: CT Study

Purpose : To evaluate the developmental patterns of the sutures and synchondroses in the central skull base. Materials and Methods : We evaluated the CT scans of 109 children(age range, 29 days to 15 years) with no skull base abnormality who had undergone axial CT of the skull base with 1-mm collimation. Using a five-tier scheme, we analyzed the developmental patterns of the 18 sutures and synchondroses related to the sphenoid and occipital bones. Results : Fusion of the sutures and synchondroses related to the sphenoid bone progressed rapidly during the first two years. Thereafter, changes in the sphenoid bone were dominated by pneumatization of the sphenoid sinus. Fusion of the synchondroses within the sphenoid body, including intersphenoidal, intrapresphenoidal, and intrapostsphenoidal synchondrosis occurred early and in most cases was graded 4. Fusion of the sphenosquamosal, sphenoethmoidal, and frontosphenoidal sutures was delayed, and residual sclerosis was a common finding. Except for Kerckring-supraoccipital synchondrosis, fusion of the six sutures and synchon-droses related to the occipital bone occurred more gradually than that of those related to the sphenoid bone. Among these, fusion of the occipitomastoidal suture and petro-occipital synchondrosis was the last to occur. Conclusion : A knowledge of the developmental patterns of sutures and synchondroses can help differentiate normal conditions from those such as fracture, osseous dysplasia, or congenital malformation, which are abnormal. Our results provide certain basic informations about skull base maturity in children.

Qualitative MRI findings in adults with 22q11 deletion syndrome and schizophrenia

Background: A genetic syndrome associated with schizophrenia, 22q11 deletion syndrome (22qDS), may represent a genetic subtype of schizophrenia (22qDS-Sz). Structural brain changes are common in schizophrenia and may involve developmental anomalies, but there are no data yet for 22qDS-Sz. The objective of this study was to assess brain structure in adults with 22qDS-Sz using magnetic resonance imaging (MRI). Methods: Brain and arterial MRI scans of 11 adults with 22qDS-Sz (mean age = 28.4 years, SD = 6.5) were systematically assessed by a neuroradiologist for qualitative anomalies. Results: A high frequency of abnormalities were found: T2 white matter bright foci (BF), 90%; developmental midline anomalies, 45%; cerebral atrophy or ventricular enlargement, 54%; mild cerebellar atrophy, 36%; skull base abnormalities, 55%; and minor vascular abnormalities, 36%. Conclusions: BF and skull base abnormalities, especially in association with neurodevelopmental midline abnormalities, may be distinguishing MRI features for a genetic subtype of schizophrenia involving a deletion on chromosome 22.

Pediatric Chiari I malformations: do clinical and radiologic features correlate?

Although Chiari I malformation is increasingly recognized in children, little is known about its clinical presentation in this age group. To evaluate the relationship between clinical and MRI features of pediatric Chiari I malformations. We performed a chart review and MRI analysis of 49 children with Chiari I malformation. The degree of tonsillar ectopia was compared with age at onset, presence of syringomyelia, and a neurologic severity score as follows: asymptomatic = 0, symptomatic with normal neurologic examination = 1, and symptomatic with abnormal examination = 2. Age at onset of symptoms ranged from 10 months to 14 years. Fifty-seven percent of patients were asymptomatic. Headache and neck pain were the most frequent complaints. Syringomyelia was detected in 14% of patients and skull base abnormalities in 50%. The magnitude of tonsillar ectopia (5 to 23 mm) correlated with severity score (p = 0.04) but not with other clinical measures. The clinical symptoms of Chiari I malformations in children are nearly identical to those seen in adults. Children with greater amounts of tonsillar ectopia on MRI are more likely to be symptomatic.

CT of Normal Variations of the Minute Central Skull Base Foramina

Purpose : To evaluate the CT appearance of normal variations in the minute central skull base foramina in in-fants and children. Materials and Methods : One hundred and fourteen children under the age of 17 years without skull base ab-normality underwent CT scanning. A high spatial frequency algorithm was used, and contiguous axial scanning parallel to the orbitomeatal line was performed from the foramen magnum to the orbital roof, with a 1-mm slice thickness. The presence or absence of eight foramina, pseudoforamina, or ossification centers including anterior presphenoidal foramen, posterior presphenoidal foramen, rostro-orbital pseudoforamen, intralateromedial postsphenoidal pseudoforamen, intrapostsphenoidal pseudoforamen, spheno-occipital pseudo-foramen, canalis basilaris medianus and intrasynchondral ossified bodies was analysed according to age. The presence of foramina or pseudoforamina was indicated if a ring-shaped structure was seen on two or more CT scans at the location anatomically predicted, and intrasynchondral ossified bodies were indicated if linear or dot-like structures with high attenuation accompanied spheno-occipital synchondrosis. Results : CT indicated that within a certain age range, various kinds of foramina, pseudoforamina, and ossifi-cation centers were frequent. The anterior presphenoidal foramen was most commonly seen in infants aged 1-12 months (16/17, 94 %); the posterior presphenoidal foramen in children less than 2 years old(27/37, 73 % ) ; the rostro-orbital pseudoforamen in children aged 2 -5 years (9/17, 53%); intrapostsphenoidal pseudoforamen in children 6 -12 years old(20/37, 54%) and spheno-occipital pseudoforamen and intrasynchondral ossified bodies in children aged 13 -16 years. The canalis basilaris medianus was identified in about 20 % of all subjects regardless of age. Conclusion : Development of the minute central skull base foramina varied greatly according to age. Knowledge of the CT appearances of such embryologic variants of the central skull base should not only help Provide an understanding of complex skull base anatomy but also identify abnormal skull base development.

The Status of Stereotactic Radiosurgery for Cerebral Metastases in 1998

The last decade has witnessed an exponential proliferation of radiosurgery facilities in the United States and around the globe, and consequently, several tens of thousands of patients have undergone this procedure for a variety of intracranial and skull-base abnormalities. Since brain metastases represent the most common intracranial neoplasm, these have become a common target for radiosurgery. We present a review paper summarizing the major issues surrounding the management of brain metastases as well as an English-language literature review of 20 independent reports, using either γ-knife or linear accelerator-based radiosurgery, with >1250 patients and >2100 lesions available for analysis. Variable reporting in the studies precludes a definitive analysis and comparison of all factors in a rigorous statistical fashion, but the composite data reveal an average local control rate of 83% and a median survival of 9.6 months, which are comparable to those in recent surgical reports. Prognostic factors for survival are beginning to be unraveled, and the most important ones appear to be the presence of fewer than three lesions, controlled extracranial disease, and Karnofsky performance score. The exact impact of dose has not been clarified, but a dose–response relationship, especially for ≥18 Gy, is emerging. The role of whole-brain radiotherapy remains unresolved; it may enhance local control but does not convincingly improve survival and, in some series, is associated with an increased risk of late complications, which appear to be less than 5% on average. The concerns regarding chronic steroid dependance and increased intracranial edema do not appear to be a common problem. With such a large base of uncontrolled evidence, this is an opportune time for conducting and completing randomized trials to validate these observations.

The Trigeminal Nerve

The trigeminal nerve is described in terms of segmental anatomy and regional pathology. The common brain stem lesions are neoplasms, vascular disease, and demyelinating processes. Common lesions affecting the cisternal segment and Meckel's cave are schwannoma, meningioma, epidermoid, vascular ectasia, and aneurysm. Common lesions affecting the cavernous segment include meningioma, trigeminal schwannoma, lymphoma, metastasis, and vascular lesions. Skull base abnormalities include chordoma, chondrosarcoma, metastasis, bone dysplasias, and Paget's disease. The peripheral divisions of the trigeminal nerve are commonly involved by adjacent inflammatory disease in the sinuses, perineural spread of malignancy, and schwannoma. Unfortunately, the anatomic site of a lesion cannot be accurately predicted on the basis of clinical symptomatology. Successful imaging evaluation must include the entire course of the trigeminal nerve from the brain stem and upper cervical cord through the peripheral branches.

Craniosynostosis

Computed tomography has proven useful in children with craniosynostosis for the evaluation of deformity of the skull base, calvarium, and parenchymal brain structures. A retrospective analysis of 24 children seen during a 4-year period who had adequate preoperative, postoperative, and follow-up scans was carried out. Bone windows were used, and both bone thinning adjacent to fused sutures and thickening of affected sutures were demonstrated. Changes in calvarial contour were easily followed. Current trends in craniofacial reconstructive surgery have placed emphasis on skull base abnormalities; these are readily measured on axial computed tomographic (CT) sections, and postoperative progress may be monitored by serial scanning. In addition, new data revealing distortion of brain structures and cerebrospinal fluid pathways in these children have been obtained with CT scans. These soft tissue abnormalities had not been appreciated before the CT era, and they add a new dimension to the evaluation of these disorders. We think that these abnormalities indicate a local pressure increase on the brain at the fusion site. The restoration of parenchymal changes toward normal during the postoperative period correlated well with cosmetic improvement.