Treatment of Chiari type I malformation in patients with and without syringomyelia: a consecutive series of 66 cases

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>The authors describe the results of performing a standard posterior craniovertebral decompression and placement, if indicated, of a syringosubarachnoid shunt for the treatment of patients with Chiari I malformation with and without syringomyelia.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>This is a retrospectively analyzed consecutive series of 66 patients (mean patient age 15 years, range 1–53 years). The uniform posterior craniovertebral decompression consisted of a small suboccipital craniectomy, a C-1 laminectomy, microsurgical reduction of the cerebellar tonsils, and dural closure with a synthetic dural graft to increase the cerebrospinal fluid space at the craniocervical junction. The presence of a large syrinx, with significant thinning of the spinal cord tissue and obliteration of the spinal subarachnoid space, particularly when combined with syrinx-related symptoms, was an indication for the placement of a syringosubarachnoid shunt.</jats:p> <jats:p>In 32 patients Chiari I malformation alone was present, and 34 in patients it was present in combination with syringomyelia. Clinical findings included pain, neurological deficits, and spinal deformity. The presence of syringomyelia was significantly associated with the presence of scoliosis (odds ratio 74.4 [95% confidence interval 8.894–622.4]).</jats:p> <jats:p>All patients underwent a posterior craniovertebral decompression procedure. In 22 of the 34 patients with syringomyelia a syringosubarachnoid shunt was also placed. The mean follow-up period was 24 months (range 3–95 months). Excellent outcome was achieved in 54 patients (82%) and good outcome in 12 (18%). In no patient were symptoms unchanged or worse at follow-up examination, including four patients who initially required a second operation for persistent syringomyelia. Pain was more likely to resolve than sensory and motor deficits after decompressive surgery.</jats:p> <jats:p>Radiological examination revealed normalization of tonsillar position in all patients. The syrinx had disappeared in 15 cases, was decreased in size in 17, and remained unchanged in two.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Posterior craniovertebral decompression and selective placement of a syringosubarachnoid shunt in patients with Chiari I malformation and syringomyelia is an effective and safe treatment. Primary placement of a shunt in the presence of a sufficiently large syrinx appears to be beneficial. The question of if and when to place a shunt, however, requires further, preferably prospective, investigation.</jats:p></jats:sec>

Delayed resolution of syrinx after posterior fossa decompression without dural opening in children with Chiari malformation Type I

“…1,11,12,18,22,26,32,35,42 Children with CM-I have smaller posterior fossae than controls, 28,38,41,45 and in 1 study, patients with an associated syrinx had yet smaller posterior fossae than CM-I patients without a syrinx. 40 Syrinx has a strong association with scoliosis as well as motor and sensory symptoms.…”

Comparación del tratamiento de la malformación de Chiari tipo I mediante craniectomía suboccipital y resección del arco posterior de C1 con o sin duroplastia

“…La realización de una descompresión de la fosa posterior con plastia dural, puede ser una buena opción para restaurar el espacio subaracnoideo en la fosa posterior 3,24 .…”

“…Según las series consultadas, la evolución clínica suele ser favorable, con resolución o disminución de los síntomas entre un 75% y un 100% de los pacientes independientemente de la técnica utilizada 3,21,22 . Aunque hay series de pacientes intervenidos sin duroplastia (incluyendo niños y adultos) que reportan porcentajes de mejoría equivalentes a los de las series en las que la cirugía incluía la duroplastia 9,22,27 , la mayor parte de los autores coinciden en afirmar que los mejores resultados se obtienen realizando la craniectomía suboccipital acompañada de duroplastia 7,8,11,24,26 .…”

“…En estudios realizados en pacientes intervenidos mediante duroplastia se describen complicaciones rela-235 2008 19: cionadas con la cirugía (meningitis, fístula de líquido cefalorraquídeo, pseudomeningocele, hemorragia o hidrocefalia) en mayor número y gravedad que en procedimientos menos agresivos 7,15,21 . También están descritas otras complicaciones menos frecuentes como la ptosis cerebelosa sintomática en craniectomías extensas, que cursa con cefalea persistente y síntomas de compresión cerebelosa o del tronco cerebral 3 . Por otra parte, en estudios realizados en pacientes intervenidos sin duroplastia se describen otro tipo de complicaciones como el agravamiento de la siringomielia o la persistencia de los síntomas que en algunos casos obliga a la reintervención, teniéndose que añadir en muchos casos la duroplastia.…”

Syrinx resolution after posterior fossa decompression in patients with scoliosis secondary to Chiari malformation type I

“…This results in decompression of the cerebellar tonsil restores the normal cerebrospinal fluid flow [7]. Several studies have shown the effectiveness of PFD for treatment of syrinx in these patients: 50-100% experienced a decrease in size of spinal cavity [5,[8][9][10][11]. Recently, Wetjen et al [12] performed a serial magnetic resonance imaging (MRI) study to establish the time course for syrinx resolution after PFD and found that the syrinx began to resolve within 3.6 months after decompression and continued to decrease for months to years.…”