Recent information regarding the nature of bulk cerebrospinal fluid formation and absorption is reviewed, integrated with previous knowledge, and applied to the clinical setting.

Cerebral capillary sequestration and blood‐brain barrier (BBB) permeability to apolipoproteins E2 (apoE2), E3 (apoE3), and E4 (apoE4) and to their complexes with sAβ1–40, a peptide homologous to the major form of soluble Alzheimer's amyloid β, were studied in perfused guinea pig brain. Cerebrovascular uptake of three apoE isoforms was low, their blood‐to‐brain transport undetectable, but uptake by the choroid plexus significant. Binding of all three isoforms to sAβ1–40 in vitro was similar with a KD between 11.8 and 12.9 nM. Transport into brain parenchyma and sequestration by BBB and choroid plexus were negligible for sAβ1–40‐apoE2 and sAβ1–40‐apoE3, but significant for sAβ1–40‐apoE4. After 10 min, 85% of sAβ1–40‐apoE4 taken up at the BBB remained as intact complex, whereas free sAβ1–40 was 51% degraded. Circulating apoE isoforms have contrasting effects on cerebral capillary uptake of and BBB permeability of sAβ. ApoE2 and apoE3 completely prevent cerebral capillary sequestration and blood‐to‐brain transport of sAβ1–40. Conversely, apoE4, by entering brain microvessels and parenchyma as a stable complex with sAβ, reduces peptide degradation and may predispose to cerebrovascular and possibly enhance parenchymal amyloid formation under pathological conditions.

Between 1979 and 1991, spinal arachnoid cysts were found in 11 patients aged 19 months to 18 years (mean age 5 1/2 years). Of the 11 patients, six had a myelomeningocele and one diastematomyelia. The presenting symptoms included radicular pain (one patient), progressive weakness (three), increasing scoliosis (one), worsening spasticity (three), and recurrent urinary tract infections and progressive constipation (one). Two patients showed no symptoms from the spinal arachnoid cyst. The distribution of lesions was as follows: cervicomedullary (one patient), cervical (one), cervicothoracic (two), thoracic (four), lumbar (two), and sacral (one). Four of the 11 arachnoid cysts (all intradural) were located anterior to the spinal cord, three of which were in children with a myelomeningocele. Only two of the cysts were extradural; both were found in the lumbosacral region, and one was associated with diastematomyelia. Eight patients were treated with fenestration and/or resection of the cyst wall. Three patients with anterior cysts were treated with shunts, a cyst-to-pleural space shunt in two and a cyst-to-subarachnoid space shunt in one. All of the patients either improved or exhibited an arrest in the progression of their symptoms. Spinal arachnoid cysts are a treatable cause of progressive neurological deficits and, in this series, were frequently found in patients with neural tube defects.

Background: Congenital central hypoventilation syndrome (CCHS) is a rare disorder affecting central control of breathing. Thus, patients require lifelong assisted ventilation. Diaphragm pacing (DP) may permit decannulation in those who are ventilator dependent only during sleep. Objective: The purpose of this study is to determine if patients with CCHS can be successfully ventilated by DP without tracheostomy. Methods: We reviewed the records of 18 CCHS patients (mean age 19.5 ± 10.1 years; 44% female) who were ventilated by DP only during sleep. Results: Prior to diaphragm pacer implantation surgery, 14 CCHS patients had been using home portable positive pressure ventilation (PPV) via tracheostomy, 1 had been on PPV via endotracheal tube, and 3 had been using noninvasive PPV (NPPV). Of the patients with tracheostomy prior to DP (n = 15), 11 (73%) were decannulated and ventilated successfully by DP without tracheostomy. Of all the patients reviewed (n = 18), 13 (72%) were successfully ventilated by DP without tracheostomy. Obesity prevented successful DP without tracheostomy in 1 patient, and upper airway obstruction prevented success in another patient. Snoring and/or obstructive apneas were present in some patients, but they were improved by diaphragm pacer changes, adenotonsillectomy, and/or use of nasal steroids. Conclusions: DP without tracheostomy can be successfully achieved in patients with CCHS. Snoring and obstructive apneas, when present, can be managed by diaphragm pacer changes and medical therapies. Obesity can pose a challenge to successful DP.

During the past 17 years, 7 children have been treated at Children’s Hospital Los Angeles (CHLA) for traumatic intracranial aneurysms. These patients presented with subarachnoid or intraparenchymal hemorrhage (5 cases), growing fracture (1 case), and behavioral change (1 case). All patients were managed with surgery, and no patient died or was made neurologically worse as a result of such management. The existence of a traumatic aneurysm should be considered when new neurological symptoms develop in a patient with a history of head injury.

Although surgical treatment of sagittal synostosis has become normative, the procedure of choice is still debated. This retrospective analysis, during a 10-year period (1986-1995) at Children’s Hospital Los Angeles, compares the more conservative strip craniectomy (SC) procedure with a more extensive occipital reduction-biparietal widening calvarial vault remodeling (CVR) technique for the management of sagittal synostosis. SC was performed in 72 patients (61%) and CVR in 46 (39%). Patients undergoing CVR were older (mean 5.3 vs. 3.0 months, p< 0.01), the procedure time longer (mean 126 min vs. 72 min, p < 0.01), intraoperative blood loss greater (mean 243 vs. 54 cm³, p < 0.01), and the frequency of intraoperative blood transfusion increased (100 vs. 38%, p < 0.01; mean volume 357 vs. 51 cm³, p < 0.01) compared to patients undergoing SC. No significant intraoperative complications occurred in either group. The total time of hospitalization was similar (mean 4.4 vs. 3.8 days, p = 0.02). No neurological, hematological, or transfusion-related complications or deaths were encountered in either group. Cosmetic outcomes were significantly better in the CVR group with 79% rated as excellent compared to 41% in the SC group (p < 0.01). Fifty-nine percent of the SC patients manifested bony defects at last follow-up visit. Two SC patients required reopera-tion for poor cosmetic outcomes; CVR was successfully employed in both cases. These findings demonstrate that CVR is superior to SC in providing immediate and lasting correction of calvarial deformities secondary to sagittal synostosis. The optimal age at time of surgery is <6 months; however, CVR can be utilized throughout infancy, while SC becomes progressively less effective after 6 months of age. No significant complications were observed in either group, despite the increased operative manipulation and greater incidence of blood transfusion in the CVR patients.

To determine the significance of cerebrospinal fluid (CSF) eosinophilia, the charts of 106 patients treated with shunt-related procedures during the calendar year 1985 were reviewed. Sixty-nine patients presented for a shunt revision; their charts were retrospectively reviewed from the time of shunt insertion until January, 1988. The remaining 37 patients had a ventriculoperitoneal shunt inserted during the study period and were subsequently followed to January, 1988. A total of 558 shunt-related procedures were performed on these patients during the study period, with a mean follow-up period of 6.9 years. The infection rate was 3.8%. Eosinophilia was diagnosed when eosinophils accounted for 8% or more of the total CSF white blood cell count. Ventricular CSF eosinophilia occurred in 36 patients sometime during their clinical course. These 36 patients required a mean of 8.5 shunt revisions, while the remaining patients required a mean of 2.5 revisions (p less than 0.001). Shunt infections were also more frequent in patients with eosinophilia (p less than 0.01). In no case was peripheral eosinophilia or a parasitic infection present. This study demonstrates that CSF eosinophilia is common in children with shunts. Children with this laboratory finding will experience more shunt failures. In addition, the new appearance of eosinophilia in the CSF of a patient with a shunt in place suggests the possibility of a shunt infection.

With the ever-growing number of pediatric patients with AIDS, the entity will likely be encountered with increasing frequency in the future. Because of the potential for neurological recovery and cure, the neurosurgeon should be cognizant of this entity.