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.

The Relationship Between Basilar Invagination and Chiari Malformation Type I: A Narrative Review.

Basilar invagination (BI) and Chiari malformation type I CM-I) are the most common adult craniovertebral junction malformations, and they are frequently associated with each other and present synchronously. The relationship between BI and CM-I has remained incompletely understood, and the choice of surgical strategy has remained controversial. This brief review focuses on the different aspects of BI and CM-I, and further discusses the relationship between these two concomitant pathologies on the basis of the concepts proposed over the last three decades.

Visual and Positional Modulation of Pendular Seesaw Nystagmus: Implications for the Mechanism.

BACKGROUND: The mechanisms of pendular seesaw nystagmus (SSN) remain unknown. METHODS: We evaluated modulation of pendular SSN by removal of visual fixation, convergence, and positional changes in 2 patients, one with bitemporal hemianopia due to a traumatic damage of the optic chiasm and the other with platybasia compressing the medulla and lower cerebellum. RESULTS: In both patients, the pendular SSN markedly decreased or disappeared with convergence, without visual fixation in darkness, during static head tilt toward each shoulder while sitting and while supine. CONCLUSIONS: The similar patterns of nystagmus modulation observed in our patients with a different etiology indicate a common role of both visual and otolithic inputs in generating pendular SSN.

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.

The role of cephalometry in assessing velopharyngeal dysfunction in velocardiofacial syndrome.

OBJECTIVE: To report our experience with cephalometry in evaluating velopharyngeal dysfunction (VPD) in velocardiofacial syndrome (VCFS) and its utility in assessing the role of cervical spine abnormalities in VPD, prior to surgical correction of VPD. DESIGN: Clinical charts and cephalometric radiographs done prior to surgery for VPD were retrospectively analyzed to ascertain velopharyngeal measurements and cervical spine abnormalities. PATIENTS: Twenty-six patients (age: 6-23 years) with molecularly confirmed VCFS. SETTING: Wake Forest University Health Sciences (1997-2005). MEASUREMENTS: Cranial base angle, nasopharyngeal depth, velum length, and Need ratio at rest, velar dimple location, and velopharyngeal length during phonation; information on presence/absence of submucous cleft palate and cervical spine abnormalities were also obtained. The relationship between C1 anterior arch abnormalities and Need ratio was examined. RESULTS: Seventy-three percent of the VCFS patients had excessive nasopharyngeal depth, 80% had an abnormal Need ratio, 50% had a short velum, 81% had a submucous or occult submucous cleft palate, 90.5% had a cervical spine abnormality (C1 anterior arch abnormalities in 38%) and 11.5% had platybasia. There was a significant difference in the Need ratio between patients with and without C1 anterior arch abnormalities. CONCLUSION: Cephalometry can be used to delineate factors such as C1 vertebral abnormalities, excessive pharyngeal depth, and short velum that contribute to VPD in VCFS. This would help otolaryngologists better understand the anatomy prior to surgical treatment of VPD. This is the first study to highlight the frequent occurrence of C1 anterior arch abnormalities in VCFS.

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.

Basilar impression and osteogenesis imperfecta: a 21-year retrospective review of outcomes in 20 patients.

OBJECT: Basilar impression (BI) secondary to osteogenesis imperfecta (OI) is a rare but debilitating condition that is often progressive unless it is halted. More recently, ventral decompression surgery has been advocated for this condition. This study is a retrospective review of the 21-year experience of ventral decompression surgery and dorsal occipitocervical fixation in patients with BI secondary to OI and is the largest patient series reported to date. METHODS: Twenty patients treated between 1982 and 2003 by the senior author at the authors' institution were included in this study. All patients underwent ventral decompression surgery followed by dorsal craniocervical stabilization. Patients were followed up for a median of 10 years. RESULTS: There were no intraoperative or perioperative deaths. Postoperatively, 16 of 20 (80%) patients showed objective improvement or maintained their good preoperative level of function. After surgery, of the 15 patients admitted with Karnofsky Performance Scale (KPS) scores of 70% or less, 11 improved, two remained unchanged, one patient's condition deteriorated, and one patient died of an unrelated cause. Of five patients admitted with a KPS score of 80% or greater, no patient's condition deteriorated in the short- and midterm period, but one patient had recurrence 15 years after surgery. At the end of follow-up, 25% of the patients had recurrence of brainstem compression symptoms or had died, and 15% showed no improvement after surgery. All of the remaining patients (60%) had sustained a long-term benefit from surgery. CONCLUSIONS: Aggressive ventral decompression surgery and dorsal stabilization for patients with BI secondary to OI can not only halt disease progression but can also produce a good and sustainable long-term functional outcome, even in those patients who present as severely symptomatic. Patients who presented early with minor symptoms had good long-term outcomes.

Basilar impression in osteogenesis imperfecta: can it be treated with halo traction and posterior fusion?

Basilar impression (BI) and hydrocephalus complicating osteogenesis imperfecta (OI) is usually treated by anterior transoral decompression and posterior fixation. Nevertheless, it may be questioned if posterior fusion following axial halo traction is adequate in patients with symptomatic BI complicating OI. We report on a case with progressive symptomatic hydrocephalus and BI complicating OI that was successfully treated by halo traction followed by posterior occipitocervical fusion. However, after a symptom free interval of 2 years the patient suffered from recurrence of symptomatic hydrocephalus needing additional ventriculoperitoneal (VP) shunt placement. In conclusion, posterior fusion without additional VP shunt placement may not be effective in the long term for ameliorating symptoms and signs and halting progressive hydrocephalus in BI complicating OI.

Halo traction in basilar invagination: technical case report.

BACKGROUND: In the management of basilar invagination, traction therapy may help by pulling down the odontoid process away from the brain stem that may result in clinical and radiological improvement. We aimed to discuss the role of the halo vest apparatus traction on the reduction of severe anterior compression pathologies in basilar invagination. CASE DESCRIPTION: We describe a simple and safe cervical traction method by the halo vest apparatus that is followed by rigid posterior occipitocervical fixation and foramen magnum decompression in a patient who presented with basilar invagination and symptoms of severe brain stem compression. An MR-suitable halo vest apparatus was used for reduction of the deformity. The reduction of the basilar invagination was achieved gradually by distracting the halo crown in stages. CONCLUSION: The halo vest apparatus can be safely used in complex craniocervical junction anomalies. An effective cervical traction can be performed in basilar invagination, and reduction of the deformity may be achieved without the risk of overdistraction. In some cases, even partial reduction of the deformity may facilitate brain stem and spinal cord relief without any need of posterior decompression. Patients may benefit from ambulatory functions because bed rest is eliminated in this procedure. Neurovascular structures and the degree of the reduction can be observed on MRIs when an MR-suitable device is used.

Osteogenesis imperfecta at the beginning of bone and joint decade.

Osteogenesis imperfecta (OI), or brittle bone disease, is a heritable disorder characterized by increased bone fragility. Four different types of the disease are commonly distinguished, ranging from a mild condition (type I) to a lethal one (type II). Types III and IV are the severe forms surviving the neonatal period. In most cases, there is a reduction in the production of normal type I collagen or the synthesis of abnormal collagen as a result of mutations in the type I collagen genes. These classic forms of OI are described in this review. There are instances, however, where alterations in bone matrix components, other than type I collagen, are the basic abnormalities of the OI. Recently, three such discrete types have been identified by histomorphometric evaluation (types V and VI) and linkage analysis (Rhizomelic OI). They provide evidence for the as yet poorly understood complexity of the phenotype-genotype correlation in OI. We also discuss bisphosphonates treatment as well as fracture management and surgical correction of deformities observed in the patients with OI. However, ultimately, strengthening bone in OI will involve steps to correct the underlying genetic mutations that are responsible for this disorder. Thus, we also describe different genetic therapeutic approaches that have been tested either on OI cells or on available OI murine models.

[A new surgical treatment for syringomyelia, scoliosis, Arnold-Chiari malformation, kinking of the brainstem, odontoid recess, idiopathic basilar impression and platybasia]. / Nuevo tratamiento quirúrgico para la siringomielia, la escoliosis, la malformación de Arnold-Chiari, el kinking del tronco cerebral, el retroceso odontoideo, la impresión basilar y la platibasia idiopáticas.

INTRODUCTION: Based on medullary traction as responsible for idiopathic syringomyelia (SMI), idiopathic scoliosis (ESCID), Arnold Chiari malformation (ARCH), platybasia (PTB), basilar impression (IMB), odontoid recess (RTO) kinking of the brain stem (KTC) and considering the medullary traction to be transmitted by the filum terminale (FT), a surgical technique for the section of FT (SFT) is described in three cases of SMI, one of ESCID, and one of ARCH with no lumbar dysraphia. MATERIAL AND METHODS: A 34-year-old woman with cervico-brachialgias, paresthesias, bilateral babinski and a centro-medullary cavity C3-C7. A 26-year-old male with cervico-brachialgias, hypoestesia in left hemybody, and cervicobulbar cavity. A 19-year-old female with ESCID since the age of 14th, with episodes of reacuting, and 38o of dorsolumbar curvature. A 67-year-old woman with intense headache, hypoesthesia of the hands, paraparesia and ARCH. A 23-year-old man with marked tetraparesia, bilateral babinski, anesthesia of both legs, SMI, ESCID, ARCH and hydrocephaly. RESULTS: After SFT: in the SMIs the thermo-algesic, disesthetic and algic dissociation disappeared. In ESCID there was a reduction to 31o in the curvature in nine months. On ARCH the headaches ceased and there was recovery of touch and paraparesia. CONCLUSIONS: SFT is a useful etiological treatment for SMI, ESCID, ARCH. Also, in ESCID it is possible to avoid stress on the medulla due to its surgical reduction.

[Platybasia, basilar groove, odontoid process and kinking of the brainstem: a common etiology with idiopathic syringomyelia, scoliosis and Chiari malformations]. / Platibasia, impresión basilar, retroceso odontoideo y kinking del tronco cerebral, etiología común con la siringomielia, escoliosis y malformación de Arnold-Chiari idiopáticas.

INTRODUCTION: A common aetiopathogenic theory for basilar groove (IMB), platybasia (PTB), odontoid retrocession (RTO), kinking of the brainstem (KTC) applied to idiopathic syringomyelia (SMI), idiopathic scoliosis (ESCID) and Arnold-Chiari malformation (ARCH) is presented. Confirmation is based on an abnormally low position of the conus medullaris (CMB) in the patients with SMI. MATERIALS AND METHOD: 292 patients with syringomyelia (SM), 231 with SMI were selected. Of these, 55 were chosen who had SMI and in whom the level of the conus medullaris (NCM) could be determined, together with the figures for SMI, IMB, PTB, RTO, KTC, ESCID and ARCH on cervical and lumbar MR. The position of the conus medullaris in 50 patients who did not have SM, ESCID nor ARCH on cervical and lumbar RM was determined. RESULTS: 32 patients had an increased basal angle (58.18%). There was an IMB in a quarter of the patients (25.45%). RTO was observed in half of the patients (47.27%). Just over one third presented a KTC. 6% of the control group had CM at the level of the body of L1, whilst 84.21% of the patients with SMI presented a partial or complete CM image at this level. CONCLUSIONS: CMB in SMIU and its close relationship with IMB, PTB, RTO AND KTC and also with ESCID and ARCH make it likely that they share the same aetiopathogenic mechanism: an abnormal lack of synchronization of the growth of the neuro-axis and the neural canal (AACNN), causing a specific disorder which is seen as different syndromes.

Syringobulbia: a surgical appraisal.

Syringobulbia is a term which has been clinically applied to brain stem symptoms or signs in patients with syringomyelia. Syringobulbia clefts are found on investigation or at necropsy caused by cutting outwards of the CSF under pressure from the fourth ventricle into the medulla. These should be differentiated from the ascending syringobulbia which may occur from upward impulsive fluid movements in a previously established syringomyelia. Clinical analysis of 54 patients suggests that bulbar features are most often found with neither of the above mechanisms but are due to the effects of pressure differences acting downward upon the hind-brain with consequent distortion of the cerebellum and brainstem, traction on cranial nerves or indentation of the brain-stem by vascular loops. The commonest symptoms in the 54 patients were headache (35), vertigo (27), dysphonia or dysarthria (21), trigeminal paraesthesiae (27), dysphagia (24), diplopia (16), tinnitus (11), palatal palsy (11) and hypoglossal involvement (11). Careful attention to hydrocephalus is advisable before craniovertebral surgery, but the decompression of the hindbrain and the correction of craniospinal pressure dissociation remains the mainstay of surgical treatment. The results of careful surgery are good, 45 of the 54 cases reported improvement. Most of the reported deterioration occurred in a few patients who did conspicuously badly.

[Autonomic nervous system disorders in 230 cases of basilar impression and Arnold-Chiari deformity]. / Neurovegetative Störungen bei 230 Fällen basilärer Impression und Arnold-Chiarischer Missbildung.

Within the period of 1971 to 1989 we operated on 230 cases of craniocervical malformations characterised by 189 cases of basilar impression associated with Arnold-chiari malformation, 28 cases of isolated basilar impression and 13 cases of Arnold-Chiari malformation. Autonomic disturbance was observed in 136 (59.1%) cases: sexual disorders like reduced potency and impotency were observed in 86 (60.9%) out of 141 male patients, urinary symptoms in 39 (17%) patients; and other autonomic features like dyspnea, anhidrosis, hyperhidrosis, Claude Bernard-Horner syndrome and constipation in 41 (17.8%) patients.

Somatosensory and brainstem auditory evoked potential in congenital craniovertebral anomaly; effect of surgical management.

Clinical features and evoked potential recordings were analysed in 32 patients with congenital atlantoaxial dislocation before and after surgery. Seven patients (group 1) had atlantoaxial dislocation, while 22 patients had associated basilar invagination (group 2). In both groups, pyramidal tract signs, posterior column signs, wasting of the upper limbs, and abnormality of somatosensory evoked potentials (SSEP) were similar. Conversely, lower cranial nerve involvement and abnormal brainstem auditory evoked potentials (BAEP) were significantly more in patients with basilar invagination (p less than 0.05). All seven patients in group 1 and 17 patients in group 2 were operated upon. Clinical and electrophysiological deterioration were significant in patients with basilar invagination (group 2), following posterior fixation compared with group 1. Among the patients in group 2, who clinically deteriorated following posterior fixation, seven had transoral excision of odontoid and six of them improved both clinically and electrophysiologically. Two patients in group 2 had odontoid excision before posterior fixation, and in both the evoked potentials improved postoperatively. In group 1 the patient's BAEP remained unaffected following posterior fixation, however, in group 2, eight patients over 53% showed improvement in brainstem function following posterior fixation. This study shows the value of evoked potentials in congenital atlantoaxial dislocation, and rationalizes the surgical procedure in these patients. In patients with basilar invagination, odontoid excision is the preferred first stage procedure.

Cervical arachnoidal cyst with basilar impression and Arnold-Chiari malformation: a case report.

A case of cervical spinal arachnoidal cyst is presented. The association with basilar impression and Arnold-Chiari malformation is a peculiarity seldom reported. The clinical aspects with remission and exacerbation are discussed. The importance of the neuroradiological findings and the usefulness of the neurophysiological examination (evoked potentials) are suggested.

Ocorrência de epilepsia na impressäo basilar / Ocurrence of epilepsy in basilar impression

Os autores analisam crises epilépticas observadas em 12 (5,2%) pacientes dentre os 230 casos operados de impresäo basilar e/ou malformaçäo de Arnold-Chiari. Algumas consideraçöes säo feitas em relaçäo às crises epilépticas e estados sincopais com o intuito de esclarecer melhor estas ocorrências clínicas. Mecanismos fidiopatogênicos, baseados em dados anatômicos e clínicos, säo propostos para os casos em estudo

Measurement of nasal potential difference in adult cystic fibrosis, Young's syndrome, and bronchiectasis.

Previous work confirmed the abnormal potential difference between the undersurface of the inferior nasal turbinate and a reference electrode in cystic fibrosis, but the technique is difficult and the results show overlap between the cystic fibrosis and the control populations. In the present study the potential difference from the floor of the nose has therefore been assessed in normal subjects, as well as in adult patients with cystic fibrosis, bronchiectasis and Young's syndrome. Voltages existing along the floor of the nasal cavity were recorded. The mean potential difference was similar in controls (-18 (SD 5) mv) and in patients with bronchiectasis (-17 (6) mv) and Young's syndrome (-20 (6) mv). The potential difference in cystic fibrosis (-45 (8) mv) was significantly different from controls (p less than 0.002) and there was no overlap between the cystic fibrosis values and values obtained in normal and diseased controls. This simple technique therefore discriminates well between patients with cystic fibrosis and other populations, raising the possibility of its use to assist in diagnosis.

Brainstem auditory evoked potential (BAEP) abnormalities in subjects with craniovertebral malformations.

We report the data on 42 monaural BAEP recordings from 10 patients with craniovertebral malformations. Of 8 preoperative recordings from 3 patients 6 showed an increased I-III interpeak latency (IPL). Of 28 recordings taken shortly (1-12 months) after surgery 21 showed an abnormal I-III IPL. On the other hand, of 6 recordings from 3 patients 20 years after surgery 5 were in the normal range and 1 showed an abnormal I-III IPL. Although the most important site of craniovertebral malformations is the cervicomedullary junction, the results reported suggest unilateral or asymmetrical bilateral involvement of the medullary-pontine junction, on the evidence of BAEP wave III, in a large proportion of patients with these malformations.

Hypoplasia of the basi-occipital bone and persistence of the spheno-occipital synchondrosis in a patient with transitory supplementary fissure of the basi-occipital.

The author had the opportunity to observe the progressive development of a special form of basilar impression characterized by transitory supplementary fissure of the basi-occipital bone, persistence of the spheno-occipital synchondrosis and hypoplasia of the basi-occipital. He proposes to dissociate the general concept of basilar impression and to consider anatomo-clinical entities such as the example described in this paper.