Sean A. McNatt

Gamma knife radiosurgery for trigeminal neuralgia.

OBJECTIVE: The purpose of this study was to assess outcomes in patients treated with gamma knife radiosurgery for trigeminal neuralgia. METHODS: From 1997 to 2003, a total of 49 patients with trigeminal neuralgia underwent gamma knife radiosurgery. The trigeminal root entry zone immediately adjacent to the pons was targeted by use of a 4-mm collimator to deliver 40 Gy to the 50% isodose line (maximum dose, 80 Gy). Special care was taken to limit radiation dose to the adjacent pons to 12 Gy. Of the 49 study patients, all had undergone previous medical therapy, 8 (16%) had undergone microvascular decompression, 8 (16%) had undergone percutaneous rhizotomy, 2 (4%) had undergone linear accelerator-based radiosurgery, and 5 (10%) presented with multiple sclerosis. The median duration of symptoms was 6 years. There were 29 female patients (59%) and 20 male patients (41%). Facial pain outcomes were assessed by use of the Barrow Neurological Institute pain score. Other outcomes assessed included recurrence of symptoms and treatment toxicity. The median follow-up period was 49 months. RESULTS: At last evaluation, a total of 27 patients (61%) with idiopathic trigeminal neuralgia reported pain relief (scores of IIIb or less). This included 14 patients (32%) who reported complete pain relief when not receiving medications. Significant recurrence of pain after an initial interval of relief was reported by 10 patients (23%). Mean time to pain recurrence was 9.6 months (range, 2–36 mo). Mild to moderate facial numbness was experienced by 13 patients (29%), whereas 8 (18%) reported mild dysesthesias. CONCLUSION: Gamma knife radiosurgery established durable pain relief in 61% of patients with medically refractory idiopathic trigeminal neuralgia. A longer follow-up period is necessary to fully assess the incidence of late complications and recurrences.

Synchronous multicentric pleomorphic xanthoastrocytoma : Case report

OBJECTIVE AND IMPORTANCE:Pleomorphic xanthoastrocytoma (PXA) is a rare, low-grade astrocytoma of adolescence. Relatively favorable outcomes have been achieved with complete surgical resection. However, few data exist regarding the treatment of recurrent, deep-seated, or multicentric lesions. We report the first case to our knowledge of synchronous multicentric PXA and discuss the related therapeutic challenges. CLINICAL PRESENTATION:A 13-year-old Hispanic girl presented with a 1-year history of progressive headaches, polyuria, and generalized fatigue. Findings from the neurological examination were notable only for the presence of papilledema. Results of laboratory studies revealed diabetes insipidus and hypothyroidism. The magnetic resonance imaging study revealed numerous nodular, homogeneously enhancing lesions, approximately 1 cm in size, scattered throughout both cerebral hemispheres. INTERVENTION:A right frontal craniotomy was performed for excisional biopsy of a superficial lesion beneath the coronal suture. Results of the histological examination were consistent with a diagnosis of PXA. The patient was treated with whole-brain radiation of 3600 cGy, with additional intensity-modulated boosts to the enhancing lesions of 1440 cGy. Three years after treatment, the patient remains neurologically nonfocal and shows no evidence of disease progression. Surgical intervention will be considered if accessible lesions progress in size on later imaging studies. CONCLUSION:Synchronous multicentric PXA presents unique challenges in that gross total resection would impose significant surgical morbidity; histological homogeneity among the lesions cannot be confirmed; and the well-described potential for anaplastic transformation may be increased with multiple lesions. The optimal treatment for patients with this rare and challenging diagnosis awaits further study.

Prevalence of cervical spine injury in infants with head trauma.

OBJECT The incidence, type, and severity of pediatric cervical spine injuries (CSIs) are related to age and mechanism of injury. In this study, the authors assessed the prevalence of CSIs in infants with head trauma treated in their institution. METHODS The authors reviewed the medical records of children younger than 1 year of age who presented to The Childrens Hospital with head injuries between January 1993 and December 2007. They excluded infants with head injuries resulting from motor vehicle accidents and known falls from heights greater than 10 ft. For each patient, collected data included age, cause of injury, diagnosis, discharge disposition, and outcome. Relevant imaging data were reviewed, and when appropriate, autopsy reports were also reviewed. RESULTS Nine hundred five infants with head trauma and without a major mechanism/cause were identified. Their mean age was 4.3 months. Of the 905 patients, only 2 cases of CSI were detected, giving a prevalence of 0.2%. The mechanism of injury in these 2 patients was nonaccidental trauma (NAT). CONCLUSIONS The study revealed a very low prevalence of CSIs in infants with head trauma (0.2%). Routine cervical spine imaging in these infants, therefore, appears to have low diagnostic yield. The mechanism of head injury was NAT in the 2 patients who sustained an associated CSI. This supports the need for more stringent cervical spine imaging criteria for the infant with suspected NAT.

Comparison of outcomes following decompressive craniectomy in children with accidental and nonaccidental blunt cranial trauma

OBJECT The goal of this study was to compare clinical outcomes following decompressive craniectomy performed for intracranial hypertension in children with nonaccidental, blunt cranial trauma with outcomes of decompressive craniectomy in children injured by other mechanisms. METHODS All children in a prospectively acquired database of trauma admissions who underwent decompressive craniectomy over a 9-year span, beginning January 1, 2000, are the basis for this study. Clinical records and neuroimaging studies were systematically reviewed. RESULTS Thirty-seven children met the inclusion criteria. Nonaccidental head trauma was the most common mechanism of injury (38%). The mortality rate in patients with abusive brain injury (35.7%) was significantly higher (p < 0.05) than in patients with other causes of traumatic brain injury (4.3%). Children with inflicted head injuries had a 12-fold increase in the odds of death and 3-fold increase in the odds of a poor outcome (Kings Outcome Scale for Closed Head Injury score of 1, 2, or 3). CONCLUSIONS Children with nonaccidental blunt cranial trauma have significantly higher mortality following decompressive craniectomy than do children with other mechanisms of injury. This understanding can be interpreted to mean either that the threshold for decompression should be lower in children with nonaccidental closed head injury or that decompression is unlikely to alter the path to a fatal outcome. If decompressive craniectomy is to be effective in reducing mortality in the setting of nonaccidental blunt cranial trauma, it should be done quite early.

Pediatric Shunt Malfunction without Ventricular Dilatation

Background/Purpose: Symptomatic ventriculoperitoneal shunt (VPS) malfunction can occur without progressive ventricular dilatation on imaging studies. A review of VPS revisions performed during an 18-month period was conducted to better characterize this cohort. The incidence of VPS malfunction without ventricular dilatation and the clinical features that may predispose to its occurrence have not been previously described. Methods: A retrospective review was conducted of all patients under the age of 18 who underwent VPS revision due to shunt malfunction from June 2001 to December 2002. The incidence of various factors that might correlate with the development of low compliance ventricles was examined. Results: One hundred and seventy-seven patients underwent a total of 287 VPS revisions during the study period; 16 patients (9%) had signs of raised intracranial pressure and showed no radiographic evidence of progressive ventricular dilatation. History of prior shunt-related ventriculitis positively correlated with the development of low compliance ventricles (Fisher’s exact test, p = 0.043). Conclusion: Nine percent of pediatric patients with symptomatic VPS malfunctions lack radiographic evidence of progressive ventricular dilatation on imaging studies. Patients with prior shunt infections are particularly at risk, necessitating increased vigilance when clinical signs and symptoms are apparent.

Anaplastic intraventricular oligodendroglioma: case report and review of the literature

BACKGROUND Intraventricular oligodendroglioma remains a rare diagnosis, with high-grade/anaplastic IVO being an even rarer subtype. These lesions vary in regard to tumor grading and clinical presentation, as compared with their intraparenchymal counterparts. A case report and review of the previous literature regarding IVO and tumor grading were conducted. CASE DESCRIPTION A case report of a patient with an anaplastic oligodendroglioma confined entirely within the ventricular system is presented. The patient underwent gross total surgical resection with perioperative shunt placement, yet developed aggressive recurrence of disease. The literature regarding the clinical presentation, methodology of diagnosis, and treatment of IVO was reviewed. Thirty-three studies reporting 70 patients with IVO were identified in the literature. Only 2 previous case reports of high-grade/anaplastic IVO were identified. Accurate diagnosis of these lesions, including immunohistochemistry, electron microscopy, and molecular/chromosomal subtyping, is imperative. Surgical resection with frequent perioperative shunting, as well as chemotherapy, remains the mainstay of therapy. Adjuvant therapies may differ significantly according to the tumor grade and molecular subtype. CONCLUSIONS Intraventricular oligodendroglioma remains an infrequently encountered lesion, yet is usually found to be low grade at the time of surgery. Anaplastic IVO is an exceedingly rare lesion, with only 3 case reports in the literature. Future therapy for these aggressive lesions may be based on susceptibility to various chemotherapeutic agents according to molecular subtyping.

Incidence of venous infarction after sacrificing middle-third superior sagittal sinus cortical bridging veins in a pediatric population

OBJECT The interhemispheric transcallosal approach offers an excellent surgical corridor for the treatment of deep-seated midline lesions. The approach typically requires the sacrifice of one or more middle-third superior sagittal sinus (SSS) cortical bridging veins, which introduces the risk of venous infarction and associated neurological injury. The authors studied the incidence of venous infarcts following this operative approach in a pediatric population. METHODS The authors performed a retrospective review of surgical cases involving pediatric patients treated at the Childrens Hospital Los Angeles between 1990 and 2007, in which an interhemispheric transcallosal operative procedure was performed and one or more middle-third SSS cortical bridging veins were occluded. Postoperative MR imaging studies done 1-3 days following the procedure were analyzed and compared with preoperative studies. RESULTS Sixty-three patients met the inclusion criteria. No patient developed MR imaging evidence of venous infarction. CONCLUSIONS The occlusion of one or more middle-third SSS cortical bridging veins related to the interhemispheric transcallosal approach resulted in no incidence of cerebral venous infarction in this pediatric population.

Proton magnetic resonance spectroscopy of hydrocephalic infants.

Objective: The authors present the first report evaluating neonates with chronic hydrocephalus using proton magnetic resonance spectroscopy (1H MRS). The goals of the study were (1) to determine absolute brain metabolite concentrations in premature infants and neonates with hydrocephalus and age-matched controls, (2) conduct an initial survey of potential biochemical abnormalities of the newborn hydrocephalic brain, and (3) determine whether 1H MRS can be used for outcome prediction in this population. Methods: Thirteen infants with chronic hydrocephalus were imaged with magnetic resonance imaging (MRI) and 1H MRS during an 18-month interval. Absolute metabolite concentrations were tabulated and compared with those of 26 age-matched controls. Metabolite abnormalities were evaluated for correlation with clinical outcome at last follow-up. Results: Mean lactate (Lac), glutamine (Gln) and alanine (Ala) concentrations in hydrocephalic patients were significantly elevated. These metabolite elevations did not correlate significantly with outcome. There was no evidence of altered neuronal maturation in patients with congenital hydrocephalus. Two patients with dramatically reduced N-acetyl-aspartate and elevated Lac had poor neurologic outcome and were found to have neurologic disease that had not been identified with prior diagnostic tests. Conclusions: Premature infants and neonates with hydrocephalus have elevated Lac, Gln and Ala compared with age-matched controls. Further investigation and follow-up is required to assess the significance of these findings. In general, 1H MRS is of limited value in predicting outcome in infants with hydrocephalus. However, 1H MRS may be useful in identifying subsets of hydrocephalic neonates that, in fact, have severe neurologic disease and poor prognosis.