Scoliosis in pediatric Chiari malformations without myelodysplasia

Abstract

A prospective study was undertaken in 1985 to better understand how the surgical manipulation of hindbrain herniation affected abnormal spinal curvature. Eleven patients under 16 years of age with Chiari malformation (not associated with myelodysplasia) and scoliosis of at least 15 degrees were studied. The mean curve angle at the time of original treatment was 29 degrees, with the convexity to the right in seven patients. The curvature was rapidly progressing in four patients. The most common presenting signs were myelopathy and weakness. Investigative procedures included spine radiographs with the patient standing and magnetic resonance (MR) imaging of the brain, spinal cord, and craniovertebral junction. Eight children had associated hydrosyringomyelia. Surgical intervention consisted of a dorsal posterior fossa decompression in all patients and a transoral ventral decompression of the cervicomedullary junction in five. All patients were followed at 3, 6, and 12 months, and at yearly intervals thereafter with clinical evaluations, spine radiographs in the standing position, and postoperative MR imaging. The mean follow-up period was 35 months. The scoliosis improved in eight patients, stabilized in one, and progressed in two. Only one child required postoperative spinal fusion and instrumentation for progression of scoliosis. Hematomyelia or hematobulbia was associated with persistent scoliosis in two patients. The presence of hydrosyringomyelia and bone erosion did not preclude curve improvement. All patients under 10 years of age had resolution of their scoliosis, despite preoperative curves of more than 40 degrees. These findings emphasize the importance of early surgical intervention, with the restoration of normal cerebrospinal fluid dynamics at the craniovertebral junction in children with symptomatic Chiari malformations.

Preoperative radiological and electrophysiological evaluation in 100 adolescent idiopathic scoliosis patients

“…Further, intramedullary tumors can present with scoliosis without neurological deficits [7]. However, the mechanism by which a syringomyelia or a Chiari malformation type 1 (CM-1) causes the scoliosis is poorly understood [11,12]. It has been suggested that an asymmetrically expanding syringomyelia causes pressure and injures the lower motor neurons in the gray matter of the anterior horn innervating the trunk muscles.…”

“…This imbalance of the paravertebral muscles may presumably cause the scoliosis [3]. Another explanation could be that patients with CM-1 have an equilibrium dysfunction disturbing the postural reflex system and causing scoliosis [11,12].…”

Syringomyelia and Arnold Chiari in scoliosis initially classified as idiopathic: Experience with 25 patients

“…In some papers, the authors distinguish between "paralytic scoliosis" and "idiopathic scoliosis" ]1, 8,11,15]. "Paralytic scoliosis" is observed with severe dysraphism in children and it is always a very evolutive scoliosis.…”

“…Some authors assume that the location of syringomyelia and the severity of neurological involvement are not related to the magnitude or location of the scoliosis [8,11]. Considering the coexistence between scoliosis and syringomyelia, Aboulker concludes that scoliosis may predispose a patient to syringomyelia, because of the appearance of radicular lesions and the modifications of the spinal CSF balance that appear on the convexity of scoliosis [1].…”

“…However, 20% of the patients with anomalies on MRI did not present neurological symptoms. In fact, many of the spinal anomalies associated with scoliosis produce no or only minimal symptoms, except in the case of tethered cords or diastematomyelia, in which motor weakness or sphincter dysfunction is common [6,7,9,11,12].…”