Tethered cord syndrome (TCS) is a clinical condition of various origins that arises from tension on the spinal cord. Radiographic findings may include the conus medullaris in a lower than normal position, fatty infiltration of the filum terminale, lipomyelomeningocele, myelomeningocele, myelocystocele, meningocele, split cord malformations, dermal sinus, anorectal malformations, and intraspinal tumors. The clinical constellation of signs and symptoms associated with TCS may include dermatologic, urological, gastrointestinal, neurological, and orthopedic findings. The current review focuses on TCS by age group of the more common causes of the condition, including myelomeningocele, lipomyelomeningocele, as well as the adult presentation of occult TCS. Pertinent review of the neuroembryology and normal anatomical position of the conus medullaris is included.

Object Decompressive craniectomy with subsequent autologous cranioplasty, or the replacement of the native bone flap, is often used for pediatric patients with traumatic brain injury (TBI) who have a mass lesion and intractable intracranial hypertension. Bone flap resorption is common after bone flap replacement, necessitating additional surgery. The authors reviewed their large database of pediatric patients with TBI who underwent decompressive craniectomy followed by bone flap replacement to determine the rate of bone flap resorption and identify associated risk factors. Methods A retrospective cohort chart review was performed to identify long-term survivors who underwent decompressive craniectomy for severe TBI with bone flap replacement from January 1, 1996, to December 31, 2011. The risk factors investigated in a univariate statistical analysis were age, sex, underlying parenchymal contusion, Glasgow Coma Scale score on arrival, comminuted skull fracture, posttraumatic hydrocephalus, bone flap wound infection, and freezer time (the amount of time the bone flap was stored in the freezer before replacement). A multivariate logistic regression model was then used to determine which of these were independent risk factors for bone flap resorption. Results Bone flap replacement was performed at an average of 2.1 months after decompressive craniectomy. Of the 54 patients identified (35 boys, 19 girls; mean age 6.2 years), 27 (50.0%) experienced bone flap resorption after an average of 4.8 months. Underlying parenchymal contusion, comminuted skull fracture, age ≤ 2.5 years, and posttraumatic hydrocephalus were significant, or nearly significant, on univariate analysis. Multivariate analysis identified underlying contusion (p = 0.004, OR 34.4, 95% CI 3.0–392.7), comminuted skull fractures (p = 0.046, OR 8.5, 95% CI 1.0–69.6), posttraumatic hydrocephalus (p = 0.005, OR 35.9, 95% CI 2.9–436.6), and age ≤ 2.5 years old (p = 0.01, OR 23.1, 95% CI 2.1–257.7) as independent risk factors for bone flap resorption. Conclusions After decompressive craniectomy for pediatric TBI, half of the patients (50%) who underwent bone flap replacement experienced resorption. Multivariate analysis indicated young age (≤ 2.5 years), hydrocephalus, underlying contusion as opposed to a hemispheric acute subdural hematoma, and a comminuted skull fracture were all independent risk factors for bone flap resorption. Freezer time was not found to be associated with bone flap resorption.

BACKGROUND AND PURPOSE: DTI is an advanced neuroimaging technique that allows in vivo quantification of water diffusion properties as surrogate markers of the integrity of WM microstructure. In our study, we investigated normative data from a large number of pediatric and adolescent participants to examine the developmental trends in DTI during this conspicuous WM maturation period.

BackgroundDiffusion tensor imaging (DTI) is a non-invasive MRI technique that has been used to quantify CNS abnormalities in various pathologic conditions. This study was designed to quantify the anisotropic diffusion properties in the brain of neonatal rats with hydrocephalus (HCP) and to investigate association between DTI measurements and cytopathology.MethodsDTI data were acquired between postnatal day 7 (P7) and P12 in 12 rats with HCP induced at P2 and in 15 age-matched controls. Animals were euthanized at P11 or P22/P23 and brains were processed with immunohistochemistry for glial fibrillary acidic protein (GFAP), ionized calcium-binding adaptor molecule (Iba-1), and luxol fast blue (LFB) to assess astrocytosis, microglial reactivity and degree of myelination, respectively.ResultsHydrocephalic rats were consistently found to have an abnormally low (at corrected p-level of <0.05) fractional anisotropy (FA) value and an abnormally high mean diffusivity (MD) value in the cerebral cortex (CX), the corpus callosum (CC), and the internal capsule (IC). Immunohistochemical analysis demonstrated trends of increasing astrocyte and microglial reactivity in HCP rats at P11 that reached statistical significance at P22/P23. A trend toward reduced myelination in the HCP rats was also found at P22/P23. Correlation analysis at P11 for the CC demonstrated statistically significant correlations (or trends) between the DTI measurement (the decreased FA and increased MD values) and the GFAP or Iba-1 rankings. The immunohistochemical rankings in the IC at P22/P23 were also significantly correlated or demonstrated a trend with both FA and MD values.ConclusionsThis study demonstrates the feasibility of employing DTI on the brain in experimental hydrocephalus in neonatal rats and reveals impairments in multiple regions of interest in both grey and white matter. A strong correlation was found between the immunohistochemical results and the changes in anisotropic diffusion properties.