Aggressive surgical management of patients with Chiari II malformation and brainstem dysfunction.

BACKGROUND/AIMS: Chiari II malformation represents a group of developmental abnormalities involving the caudal displacement of the cervicomedullary junction, pons, fourth ventricle, and medulla. This constellation of malformations is strongly associated with myelomeningocele (MM) and is a known cause of neurologic deterioration in older MM patients. We describe the evaluation and management of 4 adult MM patients who presented with brainstem compression and a retroflexed odontoid who were subject to aggressive surgical management including occipitocervical (OC) fusion with good clinical results. METHODS: Four MM patients who underwent OC fusion for new-onset brainstem dysfunction and myelopathy were identified in the practice of the principal investigator (D.W.P.) from 2003 to 2008. RESULTS: The initial evaluation of these patients included consideration of other diagnoses, such as hydrocephalus due to shunt malfunction and tethered cord. These patients were treated with aggressive surgical management. In some cases, multiple surgeries were performed. All 4 patients were treated with cervical decompression and OC fixation and initially had good outcomes. No patients required transoral decompression. Three of the 4 had stable improvement at their last follow-up appointment (mean follow-up of 9 months). CONCLUSION: Late deterioration in older MM patients may be secondary to brainstem or cervical spinal cord compression from ventral odontoid compression and Chiari II malformation, hydrocephalus, hydromyelia, or tethered cord. These patients may benefit from more than one surgery. Posterior decompression and OC fusion can avoid a morbid transoral odontoid resection, greatly improve patients' symptoms and prevent further neurologic decline.

Controlled clinical trial of dichloroacetate for treatment of congenital lactic acidosis in children.

OBJECTIVE: Open-label studies indicate that oral dichloroacetate (DCA) may be effective in treating patients with congenital lactic acidosis. We tested this hypothesis by conducting the first double-blind, randomized, control trial of DCA in this disease. METHODS: Forty-three patients who ranged in age from 0.9 to 19 years were enrolled. All patients had persistent or intermittent hyperlactatemia, and most had severe psychomotor delay. Eleven patients had pyruvate dehydrogenase deficiency, 25 patients had 1 or more defects in enzymes of the respiratory chain, and 7 patients had a mutation in mitochondrial DNA. Patients were preconditioned on placebo for 6 months and then were randomly assigned to receive an additional 6 months of placebo or DCA, at a dose of 12.5 mg/kg every 12 hours. The primary outcome results were (1) a Global Assessment of Treatment Efficacy, which incorporated tests of neuromuscular and behavioral function and quality of life; (2) linear growth; (3) blood lactate concentration in the fasted state and after a carbohydrate meal; (4) frequency and severity of intercurrent illnesses and hospitalizations; and (5) safety, including tests of liver and peripheral nerve function. OUTCOME: There were no significant differences in Global Assessment of Treatment Efficacy scores, linear growth, or the frequency or severity of intercurrent illnesses. DCA significantly decreased the rise in blood lactate caused by carbohydrate feeding. Chronic DCA administration was associated with a fall in plasma clearance of the drug and with a rise in the urinary excretion of the tyrosine catabolite maleylacetone and the heme precursor delta-aminolevulinate. CONCLUSIONS: In this highly heterogeneous population of children with congenital lactic acidosis, oral DCA for 6 months was well tolerated and blunted the postprandial increase in circulating lactate. However, it did not improve neurologic or other measures of clinical outcome.

Peripheral neuropathy in genetic mitochondrial diseases.

Peripheral neuropathy is an underrecognized but common occurrence in genetic mitochondrial disorders. To gain insight into the frequency and clinical presentation of this complication, nerve conduction studies were performed on 43 subjects with congenital lactic acidosis enrolled in a controlled clinical trial of oral dichloroacetate. Median and peroneal motor conduction studies and median and sural sensory conduction studies were performed on each patient. The mean amplitude of the peroneal motor nerve (P < 0.001) and the conduction velocities of the median (P < 0.001) and peroneal (P < 0.001) motor nerves were uniformly lower in our subjects than in healthy literature control subjects. There were no significant differences in sensory nerve conduction studies. A generalized reduction in motor nerve conduction velocity was the dominant electrophysiological abnormality in the patients in this study and was independent of age, sex, or congenital mitochondrial disorder. We postulate that cellular energy failure is the most likely common cause of peripheral neuropathy in patients with genetic mitochondrial diseases, owing to the high demand for adenosine triphosphate via aerobic carbohydrate metabolism by nerve tissue.

Endoscopic-assisted repair of craniosynostosis.

OBJECT: The goal of the craniofacial surgeon has always been the correction of form and function with prevention of associated morbidity and death. Through the pioneering work of Jimenez and Barone, minimally invasive approaches to the surgical correction of craniosynostosis are now gaining wider acceptance. Here the authors review the technique for endoscopic-assisted repair of craniosynostosis from the perspective of a new minimally invasive approach. They also assess the safety, efficacy, and results of the early treatment of infants with craniosynostosis in a small series of children who underwent surgery at this institution. METHODS: Data regarding synostosis type, operative time, patient age, blood loss, transfusion rates, duration of hospitalization, and complications were collected. Nineteen patients (12 girls and seven boys) between the ages of 1.2 and 5 months of age were treated with the endoscope-assisted technique. The mean operative time was 97 minutes. Five (26%) of 19 children received a blood transfusion. Most patients were discharged home the morning after surgery. The clinical courses of two patients who required additional major craniofacial reconstructions are discussed. There were no deaths, dural sinus tears, cerebrospinal fluid leaks, neurological injuries, or infections, and there were no complications related to the use of helmet therapy. Seventeen of the 19 patients achieved excellent cosmetic results with a single surgery. CONCLUSIONS: This small series supports larger experiences and indicates that early treatment of craniosynostosis with minimally invasive, endoscope-assisted techniques is safe; limits blood transfusion, hospital stay, and operative time; and represents a valuable alternative to the traditional calvarial reconstruction methods.

Renal manifestations of congenital lactic acidosis.

Congenital lactic acidoses (CLAs) constitute a group of rare inborn errors of mitochondrial metabolism in which cellular energy failure is the defining biochemical abnormality. We report the principal manifestations of renal dysfunction in 35 children with CLA caused by defects in either the pyruvate dehydrogenase multienzyme complex or one or more components of the respiratory chain. The most prominent renal abnormalities included bicarbonaturia, phosphaturia, hypercalciuria, complete Fanconi's syndrome, proteinuria, and decreased glomerular filtration rate. These data were compared with those from 79 previously published cases. Clinical manifestations of renal dysfunction in CLA are common and may be the first presenting sign of the disease. The glomerulus and proximal renal tubule appear to be the anatomic sites most vulnerable to abnormal mitochondrial energy transduction. We propose that the primary defect in mitochondrial energy metabolism, together with the consequent intracellular accumulation of lactate and hydrogen ions, precipitates a state of tissue injury that, unless interrupted, becomes self-perpetuating and ultimately leads to renal cell death.