, and four were unchanged after a follow-up of 1 to 6 years. He stated that of six patients with increased intracranial pressure, all were improved; of five patients with spinal cord involvement, three were improved and two were unchanged; and of seven patients with brainstem and cerebellar involvement, five were improved and two remained the same. In 1973, Foster and Hudgson 10 reported a surgical series of 47 patients with tonsillar ectopia shown myelographically. They reported cure in five, improvement in 30, no change in 11, and one postoperative death. The
Ruben J. Saez, Burton M. Onofrio and Takehiko Yanagihara
Charles H. Tator, Kotoo Meguro and David W. Rowed
patients with syringomyelia were diagnosed and 20 were treated with a syringo-subarachnoid shunt. The principal indications for the shunt operation were: significant and continuing neurological deterioration and absent or mild tonsillar ectopia as determined by myelography. There were 15 males and five females whose ages ranged from 25 to 73 years (mean 44 years). As shown in Table 1 , 15 patients had idiopathic syringomyelia, four had post-traumatic syringomyelia after complete spinal cord injuries, and one had syringomeylia secondary to spinal arachnoiditis. Four of
Favorable results with syringoperitoneal shunting
Nicholas M. Barbaro, Charles B. Wilson, Philip H. Gutin and Michael S. B. Edwards
patients is summarized in Table 3 . Of the 25 patients with “idiopathic” syringomyelia, only 15 were proven by radiological evaluation or operation to have tonsillar ectopia. However, many of these patients were evaluated before metrizamide-enhanced computerized tomography (CT) became available. If signs or symptoms of tonsillar ectopia were absent, the foramen magnum was not always fully evaluated. Thus, some or all of the remaining 10 patients may have had tonsillar ectopia. TABLE 3 Cause of syringomyelia in 39 patients Cause No. of
Implications for diagnosis and treatment
Edward H. Oldfield, Karin Muraszko, Thomas H. Shawker and Nicholas J. Patronas
to the subarachnoid space, pleura, or peritoneum; intermittent percutaneous aspiration of the syrinx; and lumboperitoneal shunting. Decompression of the foramen magnum and laminectomy from C-1 to C-2 or C-3, depending on the extent of tonsillar ectopia, relieves the symptoms caused by tonsillar compression. 3, 5, 38–41 In contrast, improvement of the symptoms related to syringomyelia occurs less frequently and is less predictable. The results from the various procedures listed above, alone or in combination, have been mixed; 30% to 40% of patients do not improve
.82.3.0493 Tonsillar ectopia and Chiari malformations: monozygotic triplets Richard K. Cavender John H. Schmidt III March 1995 82 3 497 500 10.3171/jns.1995.82.3.0497 Control of persistent hemiballismus by chronic thalamic stimulation Takashi Tsubokawa Yoichi Katayama Takamitsu Yamamoto March 1995 82 3 501 505 10.3171/jns.1995.82.3.0501 Total recanalization of a spontaneously thrombosed arteriovenous malformation Tohru Mizutani Hiroshi Tanaka Tohru Aruga March 1995 82 3 506 508 10.3171/jns.1995.82.3.0506 Preoperative
Richard K. Cavender and John H. Schmidt III
whom exhibit varying degrees of tonsillar ectopia, with one demonstrating a Chiari I malformation with associated syringomyelia. Evidence suggests that genetic predisposition has significance in the etiology of Chiari II malformations, which are frequently associated with neural tube defects. 11, 21 However, Chiari I malformations have been thought to occur sporadically with only occasional neural tube involvement. If these two categories represent a spectrum of the same entity, then the hereditary tendencies of type II should apply to type I and screening should be
Jeremy Greenlee, P. Charles Garell, Nicholas Stence and Arnold H. Menezes
Chiari malformation is a developmental disorder that is often associated with other abnormalities of the cerebrospinal axis. Despite widespread recognition of this association, there is relatively little information on the treatment of these coexisting disorders in the setting of cerebellar tonsillar ectopia. In an effort to improve the care provided to pediatric patients with Chiari malformations the authors reviewed their management practices over the last 20 years. Specifically, they recorded presenting symptoms, radiological studies, comorbidities, and management (surgical and nonsurgical) of 112 patients (all < 20 years of age) with Chiari malformation without myelodysplasia.
They found an associated syrinx in 29% of patients, basilar invagination in 17%, and scoliosis in 14%. The basal angle varied from 120 to 190° and Boogard's angle varied from 120 to 220°; both angles were larger than those measured in normal controls. The vertical height of the posterior fossa was shortened and the volume decreased as compared with normal controls.
The surgical management of this group of patients included posterior decompressive (44%), combined transoral and posterior decompressive (31%), combined posterior decompressive and posterior fusion (8%), and multiple posterior decompressive procedures in the same patient (5%).
The authors conclude that pediatric patients with a Chiari malformation should be specifically examined for evidence of additional craniovertebral malformations so that procedures are directed at correcting both the comorbidities and the herniation of the cerebellar tonsils through the foramen magnum.
Jeffery Meadows, Michael Kraut, Michael Guarnieri, Raymond I. Haroun and Benjamin S. Carson
evident and/or symptomatic presentation at or soon after birth, which frequently occurs as a result of associated central nervous system abnormalities (such as myelomeningocele) rather than as a direct result of the CM. The CMI is recognized by caudal displacement of the cerebellar tonsils through the foramen magnum and into the cervical canal. The extent of tonsillar ectopia varies, ranging from a few millimeters to several centimeters. Associated findings include a small posterior fossa, mild caudal displacement of the medulla and/or the fourth ventricle, angulation
Ghassan K. Bejjani
With the widespread use of newer neuroimaging techniques and modalities, significant tonsillar herniation is being diagnosed in more than 0.5% of patients, some of whom are asymptomatic. This puts the definition of the adult Chiari malformation to the test. The author provides a historical review of the evolution of the definition of the adult Chiari malformation in the neurosurgery, radiology, and pathology literature.
Report of four cases and a review of the literature
Kazuhiko Kyoshima, Takayuki Kuroyanagi, Fusakazu Oya, Yukihiro Kamijo, Hossam El-Noamany and Shigeaki Kobayashi
have described four patients with syringomyelia in whom hindbrain herniation was absent. All patients underwent foramen magnum decompression with C-1 laminectomy, and we ensured that sufficient CSF flowed from the foramen of Magendie. Postoperatively, clinical improvement was demonstrated in all but one patient in whom the improvement was transient. In two patients communication between the cavity and the fourth ventricle was identified. It is noteworthy that there was no case of tonsillar ectopia in our patients, but the cerebellar tonsils impacted the cisterna