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Apnea is a known complication of the Chiari II malformation presenting in infancy. Obstructive apnea secondary to bilateral abductor palsy or laryngomalacia and centrally mediated expiratory apnea with cyanosis can occur. Observations of 9 patients suggest that these forms of apnea may represent stages in a continuum of brain stem dysfunction due to the combined effects of the hindbrain malformation and its compression, hydrocephalus and progressive arachnoiditis. Obstructive apnea in some patients may be reversed by optimal control of hydrocephalus with or without cervical decompression. These patients may also develop episodes of cyanotic expiratory apnea of central origin (PEAC). This form of apnea does not respond to surgical or medical treatment and may show progressive worsening over time. Five of 6 patients with this form of apneic spell died suddenly, 2 of these died despite full recuscitative efforts. It is recommended that reports of treatment address results for both forms of apnea.

The standard treatment of hydrocephalus is the insertion of a valve-regulated ventriculoperitoneal (VP) shunt, which may result in the development or clinical worsening of an inguinal hernia or hydrocele. A review of the British Columbia's Children's Hospital experience with VP shunt insertion (1983-1994) identified 304 patients who underwent VP shunt placement, 31 of whom subsequently required herniorrhaphy, 5 suffering recurrences. Two cases exhibited areas of glial differentiation (diffusely scattered in one sac from a bilateral repair, focally present in the second unilateral hernia repair) displaying cytoplasmic staining with glial fibrillary acidic protein and S100. At time of surgical repair of case 1 (bilateral hernia repair), the tip of the VP shunt was detected within the hernia sac exhibiting glial differentiation; no glial tissue was identified in the sac from the other side. We conclude that inguinal herniation is a common complication of VP shunt insertion, and the identification of glial tissue within such an inguinal hernia is a rarer complication, possibly occurring when the shunt tip lies in close proximity to the hernial mesothelial tissue.

The extent of variation between centers in the electrophysiologic techniques used in lumbosacral selective dorsal rhizotomy (SDR) for spastic cerebral palsy was studied using a questionnaire survey. Nineteen centers completed the questionnaire, and the responses were analyzed for those 16 centers in which the extent of dorsal root section was guided by intraoperative electrophysiologic responses. Consistent techniques included: use of unipolar stimulating electrodes (11 of 15 responses); stimulation4 cm from the root exit foramen (14 of 16); separation of dorsal roots into three to eight rootlets each (14 of 16); tetanic stimulation frequency of 50 Hz (11 of 16); tetanic stimulation at 100% of threshold (13 of 16); recording from multiple lower limb muscles simultaneously (16 of 16), and using contralateral spread of the response as a major criterion of electrophysiologic abnormality (13 of 16). There was more variation (11 of 16 concurrence) with respect to the use of a constant current versus constant voltage stimulator; the location of the cathode of the stimulating electrode relative to the anode; the definition of the threshold for a response; whether threshold was determined from stimulation of a dorsal root, or individual rootlets; the type of recording electrodes (needle versus surface), and the relative importance of electrophysiologic versus clinical findings in determining how much of each dorsal root to cut. In 10 centers, SDR would proceed without the benefit of electrophysiologic guidance if the equipment should fail intraoperatively (only if quadriplegic in 4), and this had happened in 6. The results indicate significant variation in many aspects of electrophysiologically guided SDR.

Three cases of animal bites causing central nervous system injury in children are reported. Two infants suffered compound depressed skull fractures as a result of dog bites to the head. An older child suffered direct injury to the spinal cord from a tiger bite. In 2 cases, Pasteurella meningitis occurred. Pitfalls in the management of this type of problem are discussed.

Fifty consecutive children are described with spastic cerebral palsy treated with selective functional lumbar and sacral rhizotomy and followed for a minimum of 6 months. In all patients, spasticity improved postoperatively, but this was not necessarily accompanied by a functional improvement. Eighteen children who could not walk preoperatively were able to do so after rhizotomy. All 17 children who could walk preoperatively could do so following surgery, and in 15, gait was improved. Complications included transient urinary dysfunction in 4 children and sensory loss in 1. The operative procedure evolved with time: the technique of replacement laminotomy was refined; the electrophysiologic basis for selection of nerve rootlets changed after studies of nonspastic controls; smaller percentages of the L3 and L4 roots were sectioned in an attempt to prevent postoperative weakness of quadriceps, and there was a trend in the most recent patients to cut a smaller portion of all the posterior roots.

Serial estimations of serum cortisol were performed in 49 patients with craniocerebral trauma. Abnormalities of serum cortisol, including alterations in diurnal rhythm and elevations of serum cortisol level, occurred in 21 patients. The frequency and severity of the abnormalities correlated with the severity of the head injury, and there was a trend suggesting that middle fossa basal skull fractures predisposed to cortisol abnormalities. A further 6 patients were studied to assess the effects of exogenous dexamethasone, and in all patients there was suppression of elevated serum cortisol levels by the dexamethasone. The findings suggest that hypercortisolemia after head injury is related to an alteration rather than an abolition of the normal feedback mechanism.