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Elisabeth C. Jünger, David W. Newell, Gerald A. Grant, Anthony M. Avellino, Saadi Ghatan, Colleen M. Douville, Arthur M. Lam, Rune Aaslid and H. Richard Winn

The purpose of this study was to determine whether patients with minor head injury experience impairments in cerebral autoregulation. Twenty-nine patients with minor head injuries defined by Glasgow Coma Scale (GCS) scores of 13 to 15 underwent testing of dynamic cerebral autoregulation within 48 hours of their injury using continuous transcranial Doppler velocity recordings and blood pressure recordings. Twenty-nine age-matched normal volunteers underwent autoregulation testing in the same manner to establish comparison values. The function of the autoregulatory response was assessed by the cerebral blood flow velocity response to induced rapid brief changes in arterial blood pressure and measured as the autoregulation index (ARI).

Eight (28%) of the 29 patients with minor head injury demonstrated poorly functioning or absent cerebral autoregulation versus none of the controls, and this difference was highly significant (p = 0.008). A significant correlation between lower blood pressure and worse autoregulation was found by regression analysis in head-injured patients (r = 0.6, p < 0.001); however, lower blood pressure did not account for the autoregulatory impairment in all patients. Within this group of head-injured patients there was no correlation between ARI and initial GCS or 1-month Glasgow Outcome Scale scores. This study indicates that a significant number of patients with minor head injury may have impaired cerebral autoregulation and may be at increased risk for secondary ischemic neuronal damage.

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Elisabeth C. Jünger, David W. Newell, Gerald A. Grant, Anthony M. Avellino, Saadi Ghatan, Colleen M. Douville, Arthur M. Lam, Rune Aaslid and H. Richard Winn

✓ The purpose of this study was to determine whether patients with minor head injury experience impairments in cerebral autoregulation. Twenty-nine patients with minor head injuries defined by Glasgow Coma Scale (GCS) scores of 13 to 15 underwent testing of dynamic cerebral autoregulation within 48 hours of their injury using continuous transcranial Doppler velocity recordings and blood pressure recordings. Twenty-nine age-matched normal volunteers underwent autoregulation testing in the same manner to establish comparison values. The function of the autoregulatory response was assessed by the cerebral blood flow velocity response to induced rapid brief changes in arterial blood pressure and measured as the autoregulation index (ARI).

Eight (28%) of the 29 patients with minor head injury demonstrated poorly functioning or absent cerebral autoregulation versus none of the controls, and this difference was highly significant (p = 0.008). A significant correlation between lower blood pressure and worse autoregulation was found by regression analysis in head-injured patients (r = 0.6, p < 0.001); however, lower blood pressure did not account for the autoregulatory impairment in all patients. Within this group of head-injured patients there was no correlation between ARI and initial GCS or 1-month Glasgow Outcome Scale scores. This study indicates that a significant number of patients with minor head injury may have impaired cerebral autoregulation and may be at increased risk for secondary ischemic neuronal damage.

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Gerald A. Grant, Mark H. Wener, Hadi Yaziji, Neal Futran, Mary P. Bronner, Neil Mandel and Marc R. Mayberg

✓ Tophaceous pseudogout is one of the rarest forms of crystal deposition disease, typically presenting as a destructive and invasive mass involving the temporomandibular joint or the infratemporal fossa region in the absence of any other articular manifestations. Previous cases have been assumed to be caused by calcium pyrophosphate dihydrate (CPPD) crystal deposition, based on finding weakly birefringent crystals in the involved tissues. The authors present the unique case of a 65-year-old woman with a destructive and invasive facial mass extending to the middle cranial fossa with microscopic and clinical features consistent with tophaceous pseudogout. High-resolution x-ray crystallographic powder diffraction and Fourier transformed infrared spectroscopy subsequently revealed that the crystals were composed of calcium hydroxyapatite without CPPD. The patient was later found to have primary hyperparathyroidism and mild hypercalcemia. This case demonstrates that tissue deposits of calcium hydroxyapatite can cause a destructive and invasive mass containing weakly birefringent crystals and raises the question of whether previous cases attributed to tophaceous pseudogout resulting from CPPD actually were composed of birefringent calcium hydroxyapatite.

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Gerald A. Grant, Sohail K. Mirza, Jens R. Chapman, H. Richard Winn, David W. Newell, Dolors T. Jones and M. Sean Grady

Object. The authors retrospectively reviewed 121 patients with traumatic cervical spine injuries to determine the risk of neurological deterioration following early closed reduction.

Methods. After excluding minor fractures and injuries without subluxation, the medical records and imaging studies (computerized tomography and magnetic resonance [MR] images) of 82 patients with bilateral and unilateral locked facet dislocations, burst fractures, extension injuries, or miscellaneous cervical fractures with subluxation were reviewed. Disc injury was defined on MR imaging as the presence of herniation or disruption: a herniation was described as deforming the thecal sac or nerve roots, and a disruption was defined as a disc with high T2-weighted signal characteristics in a widened disc space. Fifty-eight percent of patients presented with complete or incomplete spinal cord injuries. Thirteen percent of patients presented with a cervical radiculopathy, 22% were intact, and 9% had only transient neurological deficits in the field.

Early, rapid closed reduction, using serial plain radiographs or fluoroscopy and Gardner—Wells craniocervical traction, was achieved in 97.6% of patients. In two patients (2.4%) closed reduction failed and they underwent emergency open surgical reduction. The average time to achieve closed reduction was 2.1 ± 0.24 hours (standard error of the mean).

The incidence of disc herniation and disruption in the 80 patients who underwent postreduction MR imaging was 22% and 24%, respectively. However, the presence of disc herniation or disruption did not affect the degree of neurological recovery, as measured by American Spinal Injury Association motor score and the Frankel scale following early closed reduction. Only one (1.3%) of 80 patients deteriorated, but that occurred more than 6 hours following closed reduction.

Conclusions. Although disc herniation and disruption can occur following all types of traumatic cervical fracture subluxations, the incidence of neurological deterioration following closed reduction in these patients is rare. The authors recommend early closed reduction in patients presenting with significant motor deficits without prior MR imaging.

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Anthony M. Avellino, Gerald A. Grant, A. Basil Harris, Sharon K. Wallace and Cheng-Mei Shaw

✓ In the central nervous system, recurrence of intracranial Masson's vegetant intravascular hemangioendothelioma (MVIH) is rare. To the authors' knowledge, only three recurrent intracranial cases have been reported.

The authors report the case of a 75-year-old woman with a recurrent left-sided cerebellopontine angle and middle cranial fossa MVIH. When the patient was 62 years of age, she underwent preoperative embolization and subtotal resection of the intracranial lesion followed by postoperative radiotherapy. She was well and free from disease until 9 years postoperatively when she became symptomatic. At 71 years of age, the patient again underwent preoperative embolization and near-gross-total resection of the lesion. Follow-up imaging performed 15 months later revealed tumor recurrence, and she underwent stereotactic gamma knife radiosurgery. At a 2.75-year follow-up review, the patient's imaging studies revealed stable residual tumor.

This case report is unique in that it documents the clinical and pathological features, surgical and postoperative treatment, and long-term follow-up review of a patient with recurrent intracranial MVIH and suggests that this unusual vascular lesion is a slow-growing benign tumor rather than a reactive process. Because the pathological composition of the lesion may resemble an angiosarcoma, understanding this benign vascular neoplasm is crucial so that an erroneous diagnosis of malignancy is not made and unnecessary adjuvant therapy is not given.

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Gerald A. Grant, Robert R. Rostomily, D. Kyle Kim, Marc R. Mayberg, Donald Farrell, Anthony Avellino, Larry G. Duckert, George A. Gates and H. Richard Winn

Object. In this study the authors investigate delayed facial palsy (DFP), which is an underreported phenomenon after surgery for vestibular schwannoma (VS). The authors identified 15 (4.8%) patients from a consecutive series of 314 who underwent surgery for VS between 1988 and 2000, and in whom DFP developed. Delayed facial palsy was defined as a deterioration of facial nerve function from House—Brackmann Grades 1 or 2 more than 3 days postoperatively.

Methods. All patients underwent intraoperative neurophysiological monitoring of facial nerve function. The average latency of DFP was 10.9 days (range 4–30 days). In six patients (40%) minor deterioration (≤ two House—Brackmann grades) had occurred at a mean of 10.2 days postsurgery, whereas in nine patients (60%) moderate deterioration (≥ three House—Brackmann grades) had occurred at a mean of 11.8 days postoperatively. Five (33%) of 15 patients recovered to Grade 1 of 2 function within 6 weeks of DFP onset. Of the 15 patients with DFP, 14 had completed 1 year of follow up at the time of this study. Twelve (80%) of these 15 patients recovered to Grade 1 or 2 function within 3 months, and 13 (93%) of 14 patients recovered within 1 year. In all cases, stimulation of the seventh cranial nerve on completion of tumor resection revealed the nerve to be intact, both anatomically and functionally, to proximal and distal stimulation at 0.1 mA. A smaller tumor diameter correlated with greater recovery of facial nerve function. There was no correlation between the latency or severity of or recovery from DFP, and the patient's age or sex, the surgical approach, frequency of neurotonic seventh nerve discharges, anatomical relationship of the facial nerve to the tumor, patient's history of tobacco use, or cardiovascular disease.

Conclusions. It appears that DFP is an uncommon consequence of surgery for VS. Although excellent recovery of facial nerve function to its original postoperative status nearly always occurs after DFP, the magnitude and time course of the disorder were not predictors for subsequent recovery of facial nerve function.

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Gerald A. Grant, Donald Farrell and Daniel L. Silbergeld

✓ The neurosurgical management of intrinsic brain tumors and brain metastases mandates maximum resection with preservation of functional cortex. There have been previous reports on the use of cortical somatosensory evoked potentials (SSEPs) for localization of functional cortex prior to resection. The identification of rolandic cortex with the use of intraoperative SSEP monitoring enables the neurosurgeon to tailor the surgery to achieve a greater extent of resection while minimizing the risk of morbidity. The use of continuous SSEP monitoring during resection to provide an ongoing functional assessment of somatosensory cortex has not been reported. This powerful technique is illustrated using four case examples.

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Gerald A. Grant, Joseph R. Meno, Thien-Son Nguyen, Kathe A. Stanness, Damir Janigro and H. Richard Winn

Object. Excitatory amino acid (EAA) uptake by neurons and glia acts synergistically with stereoselective transport across the blood—brain barrier (BBB) to maintain EAA homeostasis in the brain. The endogenous neuroprotectant adenosine counteracts many aspects of excitotoxicity by increasing cerebral blood flow and by producing pre- and postsynaptic actions on neurons. In the present study, the authors explored the effect of adenosine on EAA transport across the BBB.

Methods. The effects of adenosine on the permeability of the BBB and transport of aspartate and glutamate across the BBB were studied in a well-characterized isolated penetrating cerebral arteriole preparation suitable for simultaneous investigations of changes in diameter and permeability. At concentrations within the physiological to low pathophysiological range (10−7–10−6 M), the net vectorial transport of [3H]l-glutamate or [3H]l-aspartate from blood to brain was significantly attenuated, whereas there was no effect of adenosine on paracellular BBB permeability to [14C]sucrose or [3H]d-aspartate. With higher concentrations of adenosine (10−4 M and 10−3 M) the net vectorial transport of [3H]l-glutamate and [3H]l-aspartate returned toward baseline. At 10−3 M, the permeability to [14C]sucrose was significantly altered, indicating a breakdown in the BBB. The effect of adenosine (10−6 M) was blocked by theophylline, a blocker of the A1 and A2 receptors of adenosine.

Conclusions. Adenosine-mediated modulation of glutamate and aspartate transport across the BBB is a novel physiological finding.

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Mohan R. Sharma, David W. Newell and Gerald A. Grant

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Gerald A. Grant, Matthew Jolley, Richard G. Ellenbogen, Theodore S. Roberts, Joseph R. Gruss and John D. Loeser

Object. The authors have routinely performed primary autologous cranioplasty to repair skull defects after decompressive craniectomy. The high rates of subsequent bone resorption occurring in children prompted this study.

Methods. In an institutional review, the authors identified 40 (32 male and eight female) children and adolescents ranging from 4 months to 19 years of age in whom autologous cranioplasty was performed after decompressive craniectomy. The defect surface area ranged from 14 to 147 cm2. In all cases, the bone was fresh frozen at the time of the decompression. Symptomatic bone resorption subsequently occurred in 20 children (50%) in all of whom reoperation was required. The incidence of bone resorption significantly correlated with an increased skull defect area (p < 0.025). No significant correlation was found with age, sex, or anatomical location of the skull defect, number of fractured bone fragments, presence of a shunt, cause for decompressive craniectomy, method of duraplasty, or interval between the craniectomy and the cranioplasty. Reoperation to repair the resorbed autologous bone was performed 2 to 76 months after the initial procedure.

Conclusions. The use of autologous bone to reconstruct skull defects in pediatric patients after decompressive craniectomy is associated with a high incidence of bone resorption. The use of autologous bone should be reevaluated in light of the high rate of reoperation in this pediatric population.