Basilar invagination associated with chiari malformation type I: A literature review

Basilar invagination (BI) and Chiari malformation type I (CM-I) are very important anomalies that introduce instability and compression in the occipitocervical transition region and have complex clinical characteristics. These anomalies vary according to the affected structures. The present study revises current knowledge regarding the anatomy, anatomo-physiology, clinical manifestations, and radiological findings of these entities and the associated surgical treatment approaches. A bibliographic survey was performed through a search in the Medline, PubMed, SciELO, Science and LILACS databases. When associated, these craniovertebral malformations result in neurological deficits due to neural parenchyma compression; however, the presence of microtraumas due to repetitive lesions caused by the bulb and cervical marrow instability has been highlighted as a determinant dysfunction. Surgical treatment is controversial and has many technical variations. Surgery is also challenging due to the complex anatomical characteristics and biomechanics of this region. Nevertheless, advances have been achieved in our understanding of related mechanisms, and compression and atlantoaxial instability are considered key elements when selecting the surgical approach.

Cranio-vertebral transition assessment by magnetic resonance imaging in a sample of a northeast Brazilian population / Avaliação da transição crânio-vertebral por ressonância magnética em uma amostra da população do nordeste brasileiro

ABSTRACT Platybasia and basilar invagination are important alterations of the cranial-vertebral transition. Neuroimaging-based platybasia parameters include the Welcker basal angle, distance between the apex of the odontoid and Chamberlain's line, and the clivus-canal angle. This study aimed to measure and correlate these parameters in a sample from northeast Brazil. Methods Cross-sectional analysis of craniometric parameters from individuals submitted to magnetic resonance at an outpatient imaging center between 2011 and 2012. Results Of 181 analyzed cases, the Welcker basal angle averaged 128.96º (SD 6.51), median distance between apex of the odontoid and Chamberlain's line was 2.27 mm (IQR -1.23-4.47) and the median clivus-canal angle was 150.5º (IQR 143.2-157.3). The Welcker basal angle was inversely correlated to the clivus-canal angle, and correlated to the distance between the apex of the odontoid and Chamberlain's line. Conclusion There was a tendency to platibasia, basilar invagination and narrowing of the cranio-vertebral transition.

RESUMO Platibasia e invaginação basilar são importantes alterações da transição craniovertebral. Existem parâmetros importantes obtidos pela neuroimagem, como o ângulo basal de Welcker, distância do ápice do odontoide à linha de Chamberlain e o ângulo clivo-canal. Este estudo procurou medir e correlacioná-los em uma amostra do Nordeste Brasileiro. Métodos Estudo transversal com medidas de indivíduos submetidos a ressonância magnética craniana em um centro de diagnóstico por imagem entre 2011 e 2012. Resultados Dos 181 casos analisados, o ângulo basal de Welcker teve média 128.96º (DP 6.51), a distância do ápice do odontoide à linha de Chamberlain obteve mediana 2.27 mm (IIQ -1.23-4.47) e o ângulo clivo-canal mediano foi 150.5º (IIQ 143.2-157.3). O ângulo basal de Welcker foi inversamente correlacionado com o ângulo clivo-canal e diretamente correlacionado com a distância do ápice do odontoide à linha de Chamberlain. Conclusão Houve uma tendência a platibasia, invaginação basilar e estreitamento da transição craniovertebral, que poderiam ser influenciados pela natureza multirracial e por fatores antropológicos da população estudada.

3-D simulation of posterior fossa reduction in Chiari I / Simulação em 3D da redução da fossa posterior no Chiari do tipo I

ABSTRACT We proposed a 3D model to evaluate the role of platybasia and clivus length in the development of Chiari I (CI). Using a computer aided design software, two DICOM files of a normal CT scan and MR were used to simulate different clivus lengths (CL) and also different basal angles (BA). The final posterior fossa volume (PFV) was obtained for each variation and the percentage of the volumetric change was acquired with the same method. The initial normal values of CL and BA were 35.65 mm and 112.66º respectively, with a total PFV of 209 ml. Ranging the CL from 34.65 to 29.65 – 24.65 – 19.65, there was a PFV decrease of 0.47% – 1.12% – 1.69%, respectively. Ranging the BA from 122.66º to 127.66º – 142.66º, the PFV decreased 0.69% – 3.23%, respectively. Our model highlights the importance of the basal angle and clivus length to the development of CI.

RESUMO No presente estudo, propusemos a criação de um modelo computacional em 3D com elaboração de software onde dois arquivos em formato DICOM com uma TC e RNM de crânio foram usados para simular diferentes mensurações na extensão do clivus (EC) e no ângulo basal (AB). O volume final da fossa posterior (VFP) foi obtido em cada variação, bem como a percentagem de volume alterada. O tamanho inicial da EC era de 35,65 mm e o do AB era de 112.66º, com um VFP de 209 ml. Variando a EC de 34,65 para 29,65 – 24.65 e 19.65, houve uma diminuição do VFP de 0.47%, 1.12% e 1.69%, respectivamente. Variando o AB de 122,66º para 127,66º e 142,66º, o VFP diminui para 0.69% e 3.23%, respectivamente. Nosso modelo enfatiza a importância da patogênese do aumento do AB e do encurtamento do clivus no desenvolvimento do Chiari I.

Stereological and Morphometric Analysis of MRI Chiari Malformation Type-1

OBJECTIVE: In this study, we aimed to investigate the underlying ethiological factors in chiari malformation (CM) type-I (CMI) via performing volumetric and morphometric length-angle measurements. METHODS: A total of 66 individuals [33 patients (20-65 years) with CMI and 33 control subjects] were included in this study. In sagittal MR images, tonsillar herniation length and concurrent anomalies were evaluated. Supratentorial, infratentorial, and total intracranial volumes were measured using Cavalieri method. Various cranial distances and angles were used to evaluate the platybasia and posterior cranial fossa (PCF) development. RESULTS: Tonsillar herniation length was measured 9.09+/-3.39 mm below foramen magnum in CM group. Tonsillar herniation/concurrent syringomyelia, concavity/defect of clivus, herniation of bulbus and fourth ventricle, basilar invagination and craniovertebral junction abnormality rates were 30.3, 27, 18, 2, 3, and 3 percent, respectively. Absence of cisterna magna was encountered in 87.9% of the patients. Total, IT and ST volumes and distance between Chamberlain line and tip of dens axis, Klaus index, clivus length, distance between internal occipital protuberance and opisthion were significantly decreased in patient group. Also in patient group, it was found that Welcher basal angle/Boogard angle increased and tentorial slope angle decreased. CONCLUSION: Mean cranial volume and length-angle measurement values significantly decreased and there was a congenital abnormality association in nearly 81.5 percent of the CM cases. As a result, it was concluded that CM ethiology can be attributed to multifactorial causes. Moreover, congenital defects can also give rise to this condition.

Incidence of basilar invagination in patients with tonsillar herniation ? a case control craniometrical study / Incidência da invaginação basilar com heriação tonsilar ? estudo da craniometria do tipo caso-controle

A retrospective case-control study based on craniometrical evaluation was performed to evaluate the incidence of basilar invagination (BI). Patients with symptomatic tonsillar herniation treated surgically had craniometrical parameters evaluated based on CT scan reconstructions before surgery. BI was diagnosed when the tip of the odontoid trespassed the Chamberlain’s line in three different thresholds found in the literature: 2, 5 or 6.6 mm. In the surgical group (SU), the mean distance of the tip of the odontoid process above the Chamberlain’s line was 12 mm versus 1.2 mm in the control (CO) group (p<0.0001). The number of patients with BI according to the threshold used (2, 5 or 6.6 mm) in the SU group was respectively 19 (95%), 16 (80%) and 15 (75%) and in the CO group it was 15 (37%), 4 (10%) and 2 (5%).

Realizamos estudo retrospectivo tipo caso-controle baseado na avaliação craniométrica para avaliar a incidência da Invaginação Basilar (IB). Pacientes com herniação tonsilar sintomática tratada cirurgicamente foram avaliados quanto a parâmetros craniométricos obtidos em reconstrução de TC antes da cirurgia. IB foi diagnosticada quando a ponta do odontóide passava acima da linha de Chamberlain em 2, 5 ou 6,6 mm. No grupo cirúrgico (CI), a distância média da ponta do odontóide acima da linha de Chamberlain foi de 12 mm versus 1,2 mm no grupo controle (CO) (p<0.0001). O número de pacientes com IB conforme o critério diagnóstico usado (2, 5 ou 6,6 mm) foi de 19 (95%), 16 (80%) e 15 (75%) no grupo CI, respectivamente, contra 15 (37%), 4 (10%) e 2 (5%) no grupo CO. Pacientes com herniação tonsilar tinham maior incidência de IB comparados ao grupo controle.

Metric analysis of basal sphenoid angle in adult human skulls / Análise métrica do ângulo basiesfenoidal em crânios de humanos adultos

Objective To analyze the variations in the angle basal sphenoid skulls of adult humans and their relationship to sex, age, ethnicity and cranial index. Methods The angles were measured in 160 skulls belonging to the Museum of the Universidade Federal de São Paulo Department of Morphology. We use two flexible rules and a goniometer, having as reference points for the first rule the posterior end of the ethmoidal crest and dorsum of the sella turcica, and for the second rule the anterior margin of the foramen magnum and clivus, measuring the angle at the intersection of two. Results The average angle was 115.41°, with no statistical correlation between the value of the angle and sex or age. A statistical correlation was noted between the value of the angle and ethnicity, and between the angle and the horizontal cranial index. Conclusions The distribution of the angle basal sphenoid was the same in sex, and there was correlation between the angle and ethnicity, being the proportion of non-white individuals with an angle >125° significantly higher than that of whites with an angle >125°. There was correlation between the angle and the cranial index, because skulls with higher cranial index tend to have higher basiesfenoidal angle too. .

Objetivo Analisar as variações do ângulo basiesfenoidal em crânios de humanos adultos e sua relação com sexo, idade, etnia e índice crânico horizontal. Métodos Os ângulos foram medidos em 160 crânios pertencentes ao Museu do Departamento de Morfologia da Universidade Federal de São Paulo. Utilizamos duas réguas milimetradas flexíveis e um goniômetro, tendo como pontos de referência para a primeira régua a extremidade posterior da crista etmoidal e o dorso da sela turca, e, para a segunda régua, a margem anterior do forame magno e o clivo, medindo o ângulo na intersecção das duas. Resultados A média dos ângulos foi de 115,41°, não havendo correlação estatística entre o valor do ângulo e o sexo ou a idade. Houve correlação estatística entre o valor do ângulo e a etnia, e entre o ângulo e o índice crânico horizontal. Conclusão A distribuição do ângulo basiesfenoidal foi a mesma entre os sexos, havendo correlação entre o ângulo e a etnia, e sendo a proporção de indivíduos não brancos com ângulo >125° significativamente maior que a de indivíduos brancos com ângulo >125°. Houve correlação entre o ângulo e o índice crânico horizontal, pois crânios com maior índice crânico horizontal tenderam a um ângulo basiesfenoidal maior. .

Basilar invagination secondary to hypoplasia of the clivus - Is there indication for craniocervical fixation? / Invaginação basilar secundária à hipoplasia do clivo - Há indicação para fixação crânio-cervical? / Invaginación basilar secundaria a la hipoplasia del clivus - ¿Hay indicación para la fijación cráneo-cervical?

The posterior fossa decompression is a form of treatment suggested for patients with basilar invagination (BI) secondary to hypoplasia symptomatic of the clivus and atlantoaxial alignment preserved. Based on the fact that the worsening of cranial-cervical kyphosis (decrease of clivus-canal angle to less than 150o) can result in anterior brainstem compression, we propose that some patients may benefit from the cranio-cervical fixation. We present a case report of a patient with BI secondary to clivus hypoplasia who underwent cranio-cervical fixation in extension, with a reduction in clivus-canal angle and improvement of symptoms without posterior fossa decompression.

A descompressão da fossa posterior é uma das formas de tratamento sugeridas para pacientes com invaginação basilar (IB) secundária a hipoplasia sintomática de clivo e alinhamento atlanto-axial preservado. Baseado no fato de que a piora da cifose crânio-cervical (diminuição do ângulo clivo-canal para menos do que 150o) pode resultar em compressão anterior do tronco cerebral, propomos que alguns pacientes podem se beneficiar da fixação crânio-cervical. Apresentamos um caso de paciente com IB secundária a hipoplasia de clivo submetido à fixação crânio-cervical em extensão, com diminuição do seu ângulo clivo-canal e melhora dos sintomas, sem descompressão da fossa posterior.

La descompresión de la fosa posterior es una forma de tratamiento sugerido para los pacientes con invaginación basilar (IB) secundaria a hipoplasia sintomática del clivus con alineación atlantoaxial preservada. Con base en el hecho de que el empeoramiento de la cifosis cráneo-cervical (reducción del ángulo clivus-canal para menos de 150o) puede resultar en la compresión del tronco cerebral anterior, se propone que algunos pacientes pueden beneficiarse de la fijación craneocervical. Presentamos un paciente con IB secundaria a la hipoplasia del clivus sometido a fijación cráneo-cervical en extensión, con reducción del ángulo clivus-canal y mejora de los síntomas sin descompresión de la fosa posterior.

Relationship Between Findings on Brain MRI and Prognosis in Patients With Spontaneous Intracranial Hypotension

BACKGROUND: The outcome of spontaneous intracranial hypotension (SIH) is unpredictable and some patients have persistent and often incapacitating symptoms. This study was aimed to investigate whether abnormalities on initial magnetic resonance imaging (MRI) can predict the outcome in patients with SIH. METHODS: We retrospectively included 44 patients with SIH. Brain MRI was available for all patients. Treatment consisted of conservative treatment and/or high-volume epidural blood patching. Patients were divided into two groups: favorable or non-favorable group. Favorable group was defined as clinical improvement by conservative therapy or one trial of autologous epidural blood patching; non-favorable group as more than two week of admission, two or more trials of autologous epidural blood patching, or relapse of orthostatic headache. RESULTS: Twenty-one (48%) of 44 patients were classified as the favorable group. The non-favorable group had several abnormal findings on brain MRI (16 cases vs. 5 cases in favorable group, p<0.003), including platybasia (1), skull base tumor (1), Chiari I malformation (1), diffuse mild thickening and enhancement of dural and epidural layer of thoracic spine (1), pituitary enlargement (3), sagging brain (3) and subdural hemorrhage (4). In the non-favorable group, 13 out of 23 patients (57%) showed pachymeningeal enhancement in brain MRI (2 patients in favorable group, p<0.001). CONCLUSIONS: Brain MRI abnormalities were more frequently related with non-favorable outcomes in SIH. Pachymeningeal enhancement in particular could suggest an unfortunate prognosis.

Platybasia in 22q11.2 Deletion Syndrome Is Not Correlated with Speech Resonance

BACKGROUND: An abnormally obtuse cranial base angle, also known as platybasia, is a common finding in patients with 22q11.2 deletion syndrome (22q11DS). Platybasia increases the depth of the velopharynx and is therefore postulated to contribute to velopharyngeal dysfunction. Our objective was to determine the clinical significance of platybasia in 22q11DS by exploring the relationship between cranial base angles and speech resonance. METHODS: In this retrospective chart review at a tertiary hospital, 24 children (age, 4.0-13.1 years) with 22q11.2DS underwent speech assessments and lateral cephalograms, which allowed for the measurement of the cranial base angles. RESULTS: One patient (4%) had hyponasal resonance, 8 (33%) had normal resonance, 10 (42%) had hypernasal resonance on vowels only, and 5 (21%) had hypernasal resonance on both vowels and consonants. The mean cranial base angle was 136.5degrees (standard deviation, 5.3degrees; range, 122.3-144.8degrees). The Kruskal-Wallis test showed no significant relationship between the resonance ratings and cranial base angles (P=0.242). Cranial base angles and speech ratings were not correlated (Spearman correlation=0.321, P=0.126). The group with hypernasal resonance had a significantly more obtuse mean cranial base angle (138degrees vs. 134degrees, P=0.049) but did not have a greater prevalence of platybasia (73% vs. 56%, P=0.412). CONCLUSIONS: In this retrospective chart review of patients with 22q11DS, cranial base angles were not correlated with speech resonance. The clinical significance of platybasia remains unknown.

Suboccipital craniectomy with opening of the fourth ventricle and duraplasty: study of 192 cases of craniovertebral malformations / Descompressao da fossa posterior sem tonsilectomia em 192 casos de impressao basilar, malformacao de Chiari e/ou siringomielia

The prime objective in the surgical treatment of basilar impression (BI), Chiari malformation (CM), and/or syringomyelia (SM) is based on restoration of the normal cerebrospinal fluid (CSF) dynamics at the craniovertebral junction and creation of a large artificial cisterna magna, avoiding the caudal migration of the hindbrain. It is observed that a large craniectomy might facilitate an upward migration of the posterior fossa structures. There are many surgical techniques to decompress the posterior fossa; however, a gold standard approach remains unclear. The authors present the results of 192 cases of BI, CM, and SM treated between 1975 and 2008 and whose surgical treatment was characterized by a large craniectomy without tonsillectomy with the patient in the sitting position, large opening of the fourth ventricle, and duraplasty.

O principal objetivo no tratamento cirúrgico da impressão basilar, malformação de Chiari e/ou siringomielia fundamenta-se na restauração da dinâmica do líquido cefalorraqueano ao nível da transição craniovertebral e criação de cisterna magna ampla. Isto é fator importante para evitar a migração caudal das estruturas da fossa posterior. A craniectomia ampla facilita a migração cranial dessas estruturas. Existem várias técnicas cirúrgicas para descomprimir a fossa posterior, mas não há evidência sobre qual a melhor.. Os autores apresentam os resultados de 192 casos de impressão basilar, malformação de Chiari e siringomielia, operados entre 1975 e 2008, nos quais o tratamento cirúrgico se baseou em ampla craniectomia com o paciente em posição sentada, sem tonsilectomia, abertura ampla do quarto ventrículo e enxerto dural.

Impacted cisterna magna without syringomyelia associated or not with basilar impression and/or Chiari malformation / Cisterna magna impactada sem siringomielia associada ou não à impressão basilar e/ou malformação de Chiari

Objective: The objective of this paper is to analyze the surgical treatment of impacted cisterna magna without syringomyelia (SM) associated or not with basilar impression (BI) and/or Chiari malformation (CM). Method: The authors present, in this work, the results of five cases with impacted cisterna magna without SM which were associated with BI in four cases, tonsillar herniation in three patients when they were in the sitting position and in the other two cases there was not herniation in the sitting position. Results: The surgical treatment was characterized by a large craniectomy with the patient in the sitting position, tonsillectomy, large opening of the fourth ventricle and duraplasty with creation of a large artificial cisterna magna. An upward migration of the posterior fossa structures was detected by postoperative magnetic resonance imaging (MRI). Conclusion: The surgical treatment of impacted cisterna magna without SM remains unclear, however, a large craniectomy associated with tonsillectomy and creation of a large cisterna magna showed good results and a tendency of upward migration of the posterior fossa structures...

Objetivo: O objetivo deste trabalho é analisar o tratamento cirúrgico da cisterna magna impactada sem siringomielia, associada ou não com impressão basilar e malformação de Chiari. Método: Os autores apresentam os resultados de cinco casos de cisterna magna impactada associada com impressão basilar em quatro casos, com herniação tonsilar em três casos na posição sentada e em dois outros não havia herniação tonsilar na posição sentada. Resultados: O tratamento cirúrgico foi caracterizado por ampla craniectomia suboccipital com o paciente em posição sentada, tonsilectomia, abertura ampla do quarto ventrículo e enxerto dural com consequente criação de ampla cisterna magna artificial. Uma significante migração cranial das estruturas da fossa posterior foi detectada pelo emprego pós-operatório da ressonância nuclear magnética. Conclusão: O tratamento cirúrgico da cisterna magna impactada sem siringomielia permanece incerto, entretanto uma craniectomia ampla associada à tonsilectomia e criação de uma cisterna magna ampla mostrou bons resultados e tendência à migração cranial das estruturas da fossa posterior...

An analysis of surgical outcome and influencing factors in patients of congenital basilar invagination with atlantal-axial dislocation: report of 120 cases / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the surgical outcome and its influencing factors in patients of congenital basilar invagination (BI) with atlanto-axial dislocation (AAD).</p><p><b>METHODS</b>From May 2004 to August 2010, 120 patients who had BI with AAD were surgically treated with direct posterior intraoperative distraction-reduction and fixation technique, 93 patients were successfully followed up by means of questionnaire survey, telephone and clinical evaluation. Pre- and postoperative dynamic cervical X-rays, computed tomographic scans, 3-dimentional reconstruction views and magnetic resonance imaging were performed. Pre- and postoperative Japanese Orthopaedic Association (JOA) score, distance between odontoid tip and Chamberlain's line and atlantodental interval were measured to evaluate the surgical result. Statistical analysis was performed by means of paired t test and Pearson Correlation analysis.</p><p><b>RESULTS</b>There were 93 cases were followed up for 24-99 months with an average of 46.5 months. Until the final follow-up, clinical symptoms were improved in 79 patients (84.9%), and were stable in 7 patients (7.5%) and deteriorated in 4 patients (4.3%). Three patients died postoperatively (3.2%). Patients without intramedullary signal intensity change (ISIC) had better surgical outcome. Patients with compression from anterior odontoid tip and posterior bone margin of occipital foramen had the worst surgical outcome (F = 3.987, P < 0.01). Overall, good decompression and bone fusion were shown on postoperative image in 87 patients (93.5%). There were 3 deaths in this series because of basilar artery thrombosis, posterior fossa hematoma and unknown reasons each.</p><p><b>CONCLUSIONS</b>The direct posterior intraoperative distraction-reduction and fixation technique is an effective simple and safe method for the treatment of BI with AAD. Anterior compression from odontoid tip and posterior compression from bone margin of occipital foramen-atlantal posterior arch play important roles in its developing mechanism. ISIC on MRI is a predictive factor for the worse surgical outcome.</p>

Posterior fossa decompression with tonsillectomy in 104 cases of basilar impression, Chiari malformation and/or syringomyelia / Descompressão da fossa posterior com tonsilectomia em 104 casos de impressão basilar, malformação de Chiari e/ou siringomielia

The prime objective in the surgical treatment of basilar impression (BI), Chiari malformation (CM) and/or syringomyelia (SM) is based on the restoration of the normal cerebrospinal fluid (CSF) dynamics at the craniovertebral junction through the creation of a large artificial cisterna magna. A small suboccipital craniectomy has been emphasized to avoid caudal migration of the hindbrain structures into the vertebral canal. Nevertheless, the results showed downward migration of the hindbrain related to that type of craniectomy. The authors present, otherwise, the results of 104 cases of BI, CM and/or SM, whose surgical treatment was characterized by a large craniectomy with the patient in the sitting position, tonsillectomy, large opening of the fourth ventricle and duraplasty with creation of a large artificial cisterna magna. A significant upward migration of the posterior fossa structures was detected by postoperative magnetic resonance imaging.

O principal objetivo no tratamento cirúrgico da impressão basilar, malformação de Chiari e/ou siringomielia fundamenta-se na restauração dinâmica do líquido cefalorraqueano ao nível da transição craniovertebral e criação de ampla cisterna magna. Uma craniectomia suboccipital de pequenas dimensões foi proposta para evitar a migração caudal de estruturas rombencefálicas no canal vertebral. Entretanto, os resultados evidenciaram migração caudal do rombencéfalo. Os autores apresentam, por outro lado, os resultados de 104 casos de malformação de Chiari e/ou siringomielia, nos quais o tratamento cirúrgico se baseou em ampla craniectomia com o paciente em posição sentada, tonsilectomia, abertura ampla do quarto ventrículo e enxerto dural com consequente criação de ampla cisterna magna. Uma significante migração cranial das estruturas da fossa posterior foi detectada pelo emprego pós-operatório da ressonância magnética.

Acrodysostosis Associated with Symptomatic Cervical Spine Stenosis

Acrodysostosis is an extremely rare disorder characterized by short fingers and toes with peripheral dysostosis, nasal hypoplasia, and mental retardation. We report a 16-year-old Korean boy with acrodysostosis who had characteristic clinical features and cervical spine stenosis manifested by neurologic symptoms. On presentation, he complained of difficulty in raising his arms, and suffered from intermittent pain and weakness in both upper extremities. He had short stature and dysmorphic facial features, including a broad, depressed nasal bridge, small, upturned nose, bilateral epicanthal folds, and mild hypertelorism. Moderate mental retardation and sensorineural hearing loss in both ears were also present. Radiological findings included broad, short metacarpals and phalanges with cone-shaped epiphyses, bilateral Madelung deformities, hypertrophied first metatarsals, and thickening of the calvarium. Magnetic resonance imaging findings included stenosis of the cervical spine, platybasia with compression into the cervicomedullary junction, and downward displacement of the cerebellar tonsils. Here, we report a case of acrodysostosis with symptoms and signs of cervical spinal stenosis first in Korea. If it is diagnosed in the early stages, possible life-threatening complications, including spinal canal stenosis, can be managed properly and permanent neurologic sequelae might be avoided. Therefore, it is important to consider acrodysostosis in the differential diagnosis of peripheral dysostosis.

Tuberculosis of the Craniovertebral Junction with Basilar Impression: A Case Report

We report a rare case of tuberculosis as a cause of secondary basilar impression. A 35-year-old man was admitted to our hospital complaining of severe neck pain and motor weakness on both sides (upper and lower limbs). CT and MRI demonstrated C1/C2 subluxation, basilar impression, and an abscess occupying the prevertebral space. We performed a single-stage operation, comprising anterior removal of the abscess, posterior fixation, and fusion. The patient was discharged five weeks after surgery without any neurologic deficits or complications. Only few reports have been published worldwide describing cases of tuberculosis as a cause of secondary basilar impression. Tuberculosis of the craniovertebral (CV) junction should be considered, especially in young patients with mid- to long-term histories of neck pain without clear origins, to allow for early intervention.

Retrospective study of patients with Chiari: malformation submitted to surgical treatment / Estudo retrospectivo de pacientes com malformação de Chiari tratados cirurgicamente

The Chiari malformation (CM) is characterized by variable herniation of one or both cerebellar tonsils, associated or not with displacement of the hindbrain structures into the vertebral canal. This is a retrospective study of 29 patients with CM submitted to surgical procedure between 1990 and 2003. There were 14 females and 15 males whose ages ranged from 16 to 65 years. There were seven patients with isolated CM, 12 associated with syringomyelia (SM), three associated with basilar impression (BI) and seven associated with SM and BI. The surgery was based on posterior fossa decompression. In seven patients a catheter was introduced from the subarachnoid space into the III ventricle and five were submitted to tonsillectomy. Twenty-one patients improved, one worsened, one remained unchanged, four missed follow up and two died. We conclude that the best results with CM surgery are obtained by an effective posterior fossa decompression. Those CM cases associated with other abnormalities, such as SM and BI, probably need complementary techniques which will be the theme for new prospective studies.

A malformação de Chiari (MC) é o deslocamento variável de uma ou ambas as tonsilas cerebelares para o canal vertebral. Este trabalho é um estudo retrospectivo de pacientes com MC tratados com cirurgia de 1990 até 2003. Foram analisados 29 prontuários, sendo 15 pacientes do sexo masculino e 14 do feminino, com idade variando entre 16 a 65 anos. Destes, sete só apresentavam MC, 12 tinham MC associada com siringomielia (SM), três associada com impressão basilar (IB) e sete associada com SM e IB. Foi realizada descompressão da fossa posterior e plástica da dura-máter em todos. Em sete pacientes, foi acrescida a colocação de catéter do espaço subaracnóideo para o interior do IV ventrículo e em cinco a tonsilectomia. Ocorreu melhora dos sintomas em 21 pacientes, um permaneceu inalterado, houve piora em um caso, quatro não tiveram seguimento e dois faleceram. Conclui-se que a boa evolução da MC está relacionada com a descompressão efetiva da fossa posterior. Os casos de MC associadas a outras malformações, como IB e SM, talvez necessitem variações técnicas, as quais serão temas de novos estudos prospectivos.

Transoral approach to the craniovertebral junction

The transoral approach provides a safe exposure to lesions in the midline and the ventral side of the craniovertebral junction. The advantages of the transoral approach are 1) the impinging bony pathology and granulation tissue are accessible only via the ventral route; 2) the head is placed in the extended position, thus decreasing the angulation of the brainstem during the surgery; and 3) surgery is done through the avascular median pharyngeal raphe and clivus. We analyzed the clinical effects of odontoidectomy after treating 38 patients with basilar invagination. The anterior transoral operation to treat irreducible ventral compression in patients with basilar invagination was performed in 38 patients. The patientsÆ ages ranged from 34 to 67 years. Fourteen patients had associated Chiari malformation and eight had previously undergone posterior decompressive surgery. The main indication for surgery was significant neurological deterioration. Symptoms and signs included neck pain, myelopathy, lower cranial nerve dysfunction, nystagmus and gait disturbance. Extended exposure was performed in 24 patients. The surgery was beneficial to the majority of patients. There was one death within 10 days of surgery, due to pulmonary embolism. Postoperative complications included two cases of pneumonia, three cases of oronasal fistula with regurgitation and one cerebrospinal fluid leak. In patients with marked ventral compression, the transoral approach provides direct access to the anterior face of the craniovertebral junction and effective means for odontoidectomy.

O acesso transoral é uma via direta e segura às lesões situadas na linha média e na face anterior da junção craniocervical. As vantagens do acesso transoral são as seguintes:1) a compressão óssea e o tecido de granulação localizam-se anteriormente e são accessíveis pela via anterior; 2) a cabeça do paciente é colocada em extensão, diminuindo a angulação do tronco cerebral durante a cirurgia; e 3) a cirurgia é feita através de um plano avascular na linha média faríngea e clivo. Analisamos os resultados obtidos após odontoidectomia por via transoral em 38 pacientes portadores de invaginação basilar. Trinta e oito pacientes com compressão ventral da junção craniocervical foram submetidos a odontoidectomia por via transoral. A idade dos pacientes variou de 34 a 67 anos. Quatorze pacientes apresentavam associação com malformação de Chiari tipo I e 8 já haviam sido submetidos à cirurgia descompressiva por via posterior. A maioria dos pacientes apresentou nucalgia, mielopatia, déficits dos nervos cranianos baixos, nistagmo, e distúrbio da marcha. Em 24 pacientes foi necessário ampliar o acesso transoral através de miotomia do palato mole, ou osteotomia do palato duro ou maxilotomia. A cirurgia proporcionou melhora dos sintomas na maioria dos pacientes. Um paciente faleceu no pós-operatório imediato por causa de embolia pulmonar. Dois pacientes tiveram pneumonia, três apresentaram fístula oronasal com regurgitação, e um teve fístula liquórica. Em pacientes com compressão ventral irredutível da junção craniocervical, a via transoral proporcionou uma abordagem direta e ampla ao processo odontoide.

Basilar impression associated with impacted cisterna magna, spastic paraparesis and distress of balance: case report / Impressão basilar associada com cisterna magna impactada, paraparesia espástica e distúrbios do equilíbrio: relato de caso

We report on a 48 years-old man with basilar impression without syringohydromyelia, in which the cisterna magna was impacted by the cerebellar tonsils. Six months after posterior fossa decompression there was the disappearance of nuchal rigidity, vertigo, spastic paraparesis and improvement of balance. Nevertheless hyperreflexia and diminished pallesthesia of the lower limbs persisted.

O presente relato descreve um homem de 48 anos com impressão basilar, sem siringo-hidromielia, no qual a cisterna magna se achava impactada pelas tonsilas cerebelares. O quadro clínico era caracterizado, especialmente, por paraparesia espástica. Seis meses após a descompressão da fossa posterior houve regressão da rigidez de nuca, vertigem, paraparesia espástica inicialmente observadas e melhora do equilíbrio. A hiperreflexia e a hipopalestesia persistiram nos membros inferiores.