Dynamic cervicomedullary cord compression and alterations in cerebrospinal fluid dynamics in children with achondroplasia: review of an 11-year surgical case series

Object Achondroplasia may be associated with compression at the cervicomedullary junction. Determining which patients are at greatest risk for neurological complications of cervicomedullary compression can be difficult. In the current study the authors reviewed their records to determine the incidence and clinical significance of dynamic cervicomedullary stenosis and obstruction of CSF flow along with surgical outcomes following posterior fossa decompression. Methods The authors reviewed 34 consecutive cases involving symptomatic children with achondroplasia undergoing cervicomedullary decompression performed by a single surgeon over 11 years. Of these patients, 29 had undergone preoperative dynamic MRI of the cervicomedullary junction with cine (cinema) CSF flow studies; 13 of these patients underwent postoperative dynamic MRI studies. Clinical outcomes included changes in polysomnography, head circumference percentile, and fontanel characteristics. Radiographic outcomes included changes in dynamic spinal cord diameter, improvement in CSF flow at the foramen magnum, and change in the Evans ratio. Results Patients were predominantly female, with a mean age at presentation of 6.6 years and mean follow-up of 3.7 years (range 1–10 years). All patients had moderate to excellent improvement in postoperative polysomnography, slight decrease in average head circumference percentile (from 46.9th percentile to 45.7th percentile), and no subjective worsening of fontanel characteristics. The Evans ratio decreased by 2%, spinal cord diameter increased an average of 3.1 mm, 5.2 mm, and 0.2 mm in the neutral, flexed, and extended positions, respectively, and CSF flow improved qualitatively in all 3 positions. There were no postoperative infections, CSF leaks, or other major complications. None of the patients undergoing initial foramen magnum decompression performed at our medical center required reoperation. Conclusions Patients with achondroplasia and symptomatic cervicomedullary compression have increased risk of dynamic stenosis at the foramen magnum evident upon dynamic cine MRI. Operative decompression may be offered with low risk of complications or need for reoperation.

Etiology and cranial CT scan profile of nontumoral hydrocephalus in a tertiary black African hospital

Object Hydrocephalus is a common condition in the pediatric population. The cause of hydrocephalus, Evans ratio, ventricular index, and cerebral mantle thickness are some of the factors associated with poor surgical outcome. This study was conducted to evaluate the profile of these factors in the authors' patient population. Methods The authors conducted a prospective study from the August 1, 2006, to May 30, 2010. The consecutive patients were all 6 years of age or younger. The demographic information, cause of hydrocephalus, and cranial computerized measurements were taken (including widths of the frontal/occipital horns, third ventricle, and cerebral mantle thickness) and entered into the procedural forms. Results One hundred thirty-seven patients presented to the unit over the stipulated period. The male/female ratio was 1.1:1. The median age at presentation was 4 months (mean 7.3 months, range 4 days to 6 years). Myelomeningocele-associated hydrocephalus, aqueductal stenosis, and postmeningitic hydrocephalus accounted for 30.7%, 22.6%, and 17.5%, respectively, of the cases. The mean Evans ratio was 0.56 (range 0.43–0.70), the mean ventricular index was 197.18 (range 135.0–245.3), and the mean cerebral mantle was 10.8 mm (10–14 mm). Conclusions This study shows that the congenital form of hydrocephalus is the predominant variety in the authors' population. Myelomeningocele-associated hydrocephalus, aqueductal stenosis, Dandy-Walker malformation, and postmeningitic hydrocephalus are common causes of hydrocephalus.