Chiari malformation presenting in adults: a surgical experience in 127 cases

The Chiari type I malformation in two monozygotic twins and first-degree relatives

The presence of the Chiari type I malformation in 2 adult monozygotic female twins, their mother, and possibly in 2 of their 4 daughters is reported. The diagnosis was made by magnetic resonance imaging and confirmed at the time of surgery in 1 twin. Monozygosity of the twins was proved by DNA typing. The disorder in the present family should probably be classified together with the autosomal dominant craniocervical malformations. Nongenetic factors also seem to be important because the twins were discordant for the extent of herniation of the cerebellar tonsils and the presence of syringomyelia.

Chiari malformation type I in a child with velopharyngeal insufficiency

A five-year-old girl was referred for chronic and stable velopharyngeal insufficiency. Pharyngoplasty was performed, without significant improvement, and further neurological investigation was undertaken. Clinical examination and electromyography led to a suspicion of denervation of the IX, X and XI cranial nerves. Magnetic resonance imaging revealed a type 1 Chiari malformation.

Natural history and postsurgical outcome of syringomyelia

The surgical treatment of syringomyelia is still debatable and the result are often poor. Several surgical procedures, based on various proposed etiopathologies, have been developed but in many cases have proved completely ineffective. We have evaluated the follow-up of 69 syringomyelic patients, some operated on, some not, in the search for clues to the management of the disease. For this purpose we devised a rating system, which we describe. 31 patients underwent surgery while 38 received no treatment. We found that half of the patients deteriorated, whether they were operated on or not; only 1 in 5 improved and the rest remained stable. For surgical treatment to be successful, the disease must be in rapid evolution but without definite paraparesis.

Management of syringomyelia associated with Chiari malformation: comparative study of syrinx size and symptoms by magnetic resonance imaging

The authors reviewed the postoperative alteration of symptoms and syrinx size by magnetic resonance imaging (MRI) in 14 consecutive patients with syringomyelia associated with Chiari malformation. The patients were treated according to our treatment regimen and were divided into five groups according to operative modalities: (1) only foramen magnum decompression (D) for small syrinx; (2) D with ventriculoperitoneal (VP) shunt for small syrinx with hydrocephalus; (3) D with syringosubarachnoid (SS) shunt or (4) D with syringoperitoneal (SP) shunt for large syrinx; and (5) only VP shunt for syrinx with hydrocephalus and atlantoaxial dislocation, respectively. From the preoperative and postoperative sagittal MR images, the areas of the spinal cord and syrinx were measured by a digitizer and the syringo-cord (S-C) ratio was calculated. Out of 14 patients, 12 showed a reduction of syrinx size and a stabilization or improvement of symptoms after surgery. In the other two patients, the syrinx size did not change and their symptoms worsened. Magnetic resonance imaging follow-up showed that foramen magnum decompression without shunt is effective for patients with a small syrinx below 35% of the S-C ratio, and foramen magnum decompression with shunt was effective for patients with a large syrinx over 35% of the S-C ratio, but there was no significant difference between the SS and SP shunt group.

Surgical management of Chiari malformation and syringomyelia: Experience in 14 cases

Our experience with 14 patients afflicted with symptomatic Chiari malformation and syringomyelia, who were treated at King Khalid University Hospital between 1983 and 1990, is analyzed with reference to presentation, management, operative findings, and outcome. Patients with associated myelomeningocele, tethered cord, and spinal cord tumors were excluded from this series. The wide variations in natural history and clinical findings are emphasized. Neuroradiological studies included plain roentgenograms, myelograms, metrizamide-enhanced computed tomograms, and more recently magnetic resonance imaging scans. Posterior fossa decompression was the standard operation; other surgical procedures included syringosubarachnoid shunt, ventriculoperitoneal shunt, transoral odontoid resection, and terminal ventriculostomy. Four patients experienced definite improvement following surgery; the condition in seven was unchanged, and three suffered worsening of the disorder despite operation.

CT myelography in communicating syringomyelia

Although the etiology of syringomyelia is not clearly understood, many surgical methods have been proposed for its treatment. One widely used technique in cases of communicating syringomyelia is that of posterior fossa decompression and plugging of the obex (Gardner's Operation). In this paper we present five cases of syringomyelia which were investigated using detailed myelo-computerized tomographic techniques, of which two appeared to be communicating syringomyelia and which were treated by posterior fossa decompression and obex plugging. We also discuss the place of computed tomography in the differential diagnosis of communicating syringomyelia.

Basichondrocranium anomalies in adult Chiari type I malformation: a morphometric study

The purpose of this study was to determine the frequency of anomalies of the basichondrocranium in a series of 42 patients with Chiari type I malformation compared with a control group of 46 subjects. Sixteen patients also had syringomyelia. Linear, angular and posterior fossa surface area measurements were taken on conventional lateral skull x-rays. Posterior fossa volume was estimated by CT scanning. In patients there was shortening of clivus length, Twining-opisthion distance and Chamberlain's line. Basal and Boogard angles were enlarged. The size of the posterior fossa was smaller in patients than in controls. Only 10 (23.8%) patients had no evidence of occipital dysplasia. When discriminant analysis was applied to the data, the most discriminative variables were posterior fossa area and clivus length which allowed accurate identification of 76% of patients as belonging to the patient group and 79% of controls as belonging to the control group. These findings prove that under-development of the basichondrocranium with a small size of the posterior fossa is an outstanding feature in adult Chiari type I malformation, and support the hypothesis that tonsillar ectopia is secondary to the disproportion between the posterior fossa and the cerebellum, which is forced to grow into the cervical spinal canal.

Syringo-subarachnoid shunt for syringomyelia associated with Chiari malformation (type 1)

The authors report the surgical results of 28 patients with syringomyelia associated with Chiari malformation (type 1). 28 patients underwent 34 operative procedures. Syringo-subarachnoid shunt was performed in 28 patients, foramen magnum decompression with syringo-subarachnoid shunt in three, ventriculo-peritoneal shunt in one, terminal syringostomy in one, and foramen magnum decompression with terminal syringostomy in one. In an average postoperative follow-up period of 3 years and 9 months ranging from one year to 7 years and one month, neurological symptoms and signs improved in 24 out of 28 patients (82%). Some improvement was noted in sensory deficit and motor weakness. In 3 patients, the symptoms did not change. In 3 patients whose symptoms were unchanged, preoperative studies demonstrated atrophy of the spinal cord, in which irreversible changes were shown. The symptoms deteriorated in one patient. In one patient whose symptoms increased 3 months after syringo-subarachnoid shunt, shunt insufficiency due to postoperative adhesive arachnoiditis was responsible for neurological deterioration. The authors propose that syringo-subarachnoid shunt is effective as a surgical procedure for syringomyelia associated with Chiari malformation (type 1) if the patient does not have symptoms due to Chiari malformation or has only mild signs and symptoms which do not require foramen magnum decompression, such as nystagmus or atrophy of sternocleidomastoid muscle.

Syringomyelia with spontaneous resolution

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Successful treatment of adult Arnold-Chiari malformation associated with basilar impression and syringomyelia by the transoral anterior approach

A case of adult type I Arnold-Chiari malformation associated with basilar impression, syringomyelia, atlantoaxial dislocation, and occipitalization of the atlas is reported. Preoperative magnetic resonance imaging clearly revealed evidence of severe anterior compression of the cervicomedullary junction due to basilar impression and a sharp clivoaxial angle. Therefore, transoral anterior decompression and fusion were performed, resulting in an improvement of the patient's neurologic signs and symptoms. Postoperative magnetic resonance imaging showed an obvious reduction of the tonsillar herniation and syringomyelia, as well as an improvement of the cervicomedullary compression.

Chiari type I malformation in children

We reviewed the recent experience at Texas Children's Hospital by examining the records of 11 children who underwent suboccipital decompression for symptomatic Chiari type I malformation. Presenting complaints included neck pain (1 child), scoliosis (4 children), back pain (1 child), torticollis (1), motor dysfunction (1), and apnea (3 children). Neurologic findings were normal in 7 of the 11 children. The craniocervical junction and medulla were studied by magnetic resonance imaging, which revealed anatomy consistent with Chiari type I malformation in all cases. At surgery, all patients had tonsillar herniation to the first cervical vertebra or below. Three patients had syringomyelia. Postoperatively, either the patients were symptom free or, in the cases of scoliosis and torticollis, there was no progression. Our experience suggests that Chiari type I malformation may occur in childhood with varied and unusual clinical findings. Magnetic resonance imaging was essential to the diagnosis; the presence of tonsillar herniation was confirmed at surgery. The results of suboccipital decompression were favorable in this series.

Symptomatic Chiari malformations. An analysis of presentation, management, and long-term outcome

The Chiari malformation is a condition characterized by herniation of the posterior fossa contents below the level of the foramen magnum, and is categorized into three types based on the degree of herniation. The authors review their surgical experience between 1975 and 1985 with 50 patients afflicted with symptomatic Chiari malformations. Any patient with associated myelomeningocele, tethered spinal cord, lipoma, or diastematomyelia was excluded from this series. Forty-one patients had Chiari I malformations, seven were classified as having Chiari II, and two as having Chiari III. The presentation of pediatric and adult patients was identical. Treatment was directed at the posterior fossa pathology. Seven patients with accompanying ventral bone compression underwent transoral decompression of the cervicomedullary junction, 42 had posterior decompressive procedures, and six received ventriculoperitoneal shunts. The posterior decompression included opening the outlet foramina of the fourth ventricle, occluding any communication between the spinal cord central canal and the obex, shunting the fourth ventricle, and placing a dural graft. Postoperatively, 20% of the patients are asymptomatic, 66% improved, and 8% stabilized; in 6% the disease has progressed in spite of multiple procedures. Preoperative signs that are predictive of a less favorable outcome include muscle atrophy, symptoms lasting longer than 24 months, ataxia, nystagmus, trigeminal hypesthesia, and dorsal column dysfunction (p less than 0.05, chi-square test). A model based on the presence or absence of atrophy, ataxia, and scoliosis at the time of the preoperative examination has been generated that allows prediction of long-term outcome at the 95% confidence level.

Foramen magnum decompression versus terminal ventriculostomy for the treatment of syringomyelia

The A.A review 30 consecutive cases of syringomyelia operated on during the last seven years. Six terminal ventriculostomies (TV) and twenty-seven procedures for foramen magnum decompression (FMD) were performed. All patients of TV group had CT-myelography (CTM) and/or NMR controls at different times after surgery. Clinical results are as follows: 1) of the 6 patients who had TV, only one showed an improvement while five continued to deteriorate and three of them needed a FMD, one a cysto-peritoneal shunt and the last one died from lung cancer. 2) of the 27 patients who had FMD, twenty improved, four were unchanged and three worsened. 3) no surgical deaths occurred in this series. Postoperative NMR monitoring represents an effective non-invasive neuroradiological procedure that allows follow-up of syrinx evolution over the years.

Chiari I malformation with syringomyelia. Evaluation of surgical therapy by magnetic resonance imaging

Five patients with a Chiari I-syringomyelia complex of adult onset were evaluated by magnetic resonance (MR) imaging. All patients underwent suboccipital craniotomy with upper cervical (C-1 and part of C-2) laminectomy, arachnoid retraction, and duraplasty. Postoperative MR studies of four patients disclosed collapse of the syringomyelic cavity, even when the cavity extended into the thoracic region. This appeared to be a progressive process taking place over several weeks. Operative complications are noted and physiological implications are discussed.

Hydromyelia: a critical review

The author reviews current concepts involving the etiology, pathogenesis, and treatment of hydromyelia. A critical evaluation of current surgical approaches in relation to the type of hydromyelia present is discussed.

Treatment of syringomyelia with a syringosubarachnoid shunt

The surgical results in 40 patients with syringomyelia, treated with a syringosubarachnoid shunt or other procedures are reviewed. The principal indication for surgery was that of significant neurological deterioration. There were 12 patients with idiopathic syringomyelia without tonsillar ectopia, 12 with an associated Chiari malformation, 11 with post-traumatic syringomyelia and five patients with spinal arachnoiditis. There were 38 syringosubarachnoid shunts performed in 35 patients, and an excellent or good result was achieved in 26 patients (74.3%). In terms of the type of syringomyelia, the best results were obtained in the idiopathic group without tonsillar ectopia and in the post-traumatic group. A short duration of pre-operative symptoms favoured a better outcome, and in our opinion, early surgical treatment is indicated for all patients with neurological deterioration. All eight patients in whom a posterior fossa decompression was performed as the initial surgical procedure required a second operation, either a syringosubarachnoid or syringoperitoneal shunt to achieve neurological improvement or stabilization. Thus, the syringosubarachnoid shunt is an effective therapeutic modality for patients with syringomyelia, particularly for the idiopathic and post-traumatic groups. More than one surgical procedure may be required to achieve cessation of deterioration. Overall, excellent or good results were achieved in 29 (72.5%) of the 40 patients.

Refractory torticollis: an uncommon complication of adenotonsillectomy

We report the case of an 8-year-old boy with refractory torticollis post-adenotonsillectomy who was later found to have Arnold-Chiari malformation. The differential diagnosis, roentgenographic findings and medical and surgical management of this disorder are discussed.

The incidence of craniocervical bony anomalies in the adult Chiari malformation

Detailed linear, angular and surface area measurements were undertaken on the lateral skull radiographs of 32 patients with proven idiopathic adult Chiari type 1 malformation. Basal angles were larger, the clivus was shorter and Klaus' index was reduced in patients compared to normal controls. The size of the posterior fossa was smaller in patients than in controls. By discriminant analysis of the skull X-ray data it was possible to identify correctly two thirds of patients as belonging to the patient group. The findings indicate that craniocervical bony anomalies in the adult Chiari malformation are commoner than was previously realised, and they support the view that tonsillar herniation in these patients results from bony occipital dysplasia.

Diagnosis and management of anomalies of the craniovertebral junction

The term craniovertebral junction refers to an area comprising the inferior portion of the occipital bone surrounding the foramen magnum and the first two cervical vertebrae. A variety of anomalies of bony, meningeal, and neural elements are known to occur in this region, producing a wide spectrum of clinical symptoms. These can range from dizziness, ataxia, and nuchal headaches to obvious quadriparesis and cranial nerve palsies. Often the symptoms are vague with an evolution marked by temporary exacerbations and remissions. The diagnosis can be difficult, and in our experience is best achieved by combining a neurotologic and neurologic evaluation. We discuss here the symptoms and diagnosis in ten patients with lesions at the craniovertebral junction. The surgical management of two cases of basilar invagination is described, and the controversies regarding the technique are discussed.

Chiari type I malformation with an associated intramedullary schwannoma

A case of Chiari type I malformation associated with a cervical intramedullary schwannoma is presented. A review of the literature concerning intramedullary schwannomas revealed their most frequent location to be in the cervical region. Their optimal treatment seems to be total removal as early in the course as is feasible. Emphasis is given to the need for actual demonstration of the cystic nature of the swollen spinal cord when dealing with Chiari type I malformation.

The natural history and the influence of surgical treatment in syringomyelia

A retrospective analysis was made of the natural history and treatment of 44 patients with syringomyelia, followed for a median interval of 10 years after diagnosis. Twenty-four patients were treated surgically. Four of 12 patients who had a laminectomy with aspiration of the syrinx or syringostomy, and 7 of 15 patients who underwent decompression and exploration of the cervicomedullary junction, showed sustained improvement or stabilisation of their neurological deficits. When symptoms had been present for more than 2 years, when there was a moderate or severe neurological disability, and when the patient was more than 40 years old, the long-term outlook of posterior fossa surgery was usually poor. Of the 20 patients who did not have an operation, 7 had no further progression in symptoms after presentation and prolonged survival was usual. It is concluded that in many cases syringomyelia is compatible with prolonged survival, and although improvement can follow surgery, its influence on the disease in the long-term is uncertain.

Surgical treatment of syringomyelia. Favorable results with syringoperitoneal shunting

The authors reviewed the clinical findings, radiological evaluation, and operative therapy of 39 patients with syringomyelia. Syringoperitoneal (SP) shunting was used in 15 patients and other procedures were used in 24 patients. Follow-up periods ranged from 1 1/2 to 12 years. During the period of this study, metrizamide myelography in conjunction with early and delayed computerized tomography scanning replaced all other diagnostic procedures in patients with syringomyelia. Preoperative accuracy for the two procedures was 87%. The most common symptoms were weakness (79%), sensory loss (67%), pain (38%), and leg stiffness (28%). Surgery was most effective in stabilizing or alleviating pain (100%), sensory loss (81%), and weakness (74%); spasticity, headache, and bowel or bladder dysfunction were less likely to be reversed. Approximately 80% of patients with idiopathic and posttraumatic syringomyelia and 70% of those with arachnoiditis improved or stabilized. Better results were obtained in patients with less severe neurological deficits, suggesting the need for early operative intervention. A higher percentage of patients had neurological improvement with SP shunting than with any other procedure, especially when SP shunting was the first operation performed. Patients treated with SP shunts also had the highest complication rate, most often shunt malfunction. These results indicate that SP shunting is effective in reversing or arresting neurological deterioration in patients with syringomyelia.