Cervical spinal cord stimulation for prevention and treatment of cerebral vasospasm after aneurysmal subarachnoid hemorrhage: clinical and radiographic outcomes of a prospective single-center clinical pilot study.

BACKGROUND: Cerebral vasospasm induced by aneurysmal subarachnoid hemorrhage (aSAH) is a major cause of high morbidity and mortality, for which there is no consistently effective treatment. Cervical spinal cord stimulation (cSCS) has been shown to induce vasodilatation and improve peripheral and cerebral blood flow in both animal and human studies. This pilot study was performed to assess the clinical effect and long-term results of cSCS treatment in aSAH patients. METHODS: This was the first IRB- and US FDA-approved prospective non-randomized non-controlled study comprising of 12 aSAH patients (8 women, 4 men, age range 34-62 years) treated between May and November 2008. All patients underwent up to 2 weeks of cSCS with a single percutaneously implanted 8-contact electrode. Neurological outcomes at discharge and follow-up of up to 13 years and mortality/complications rates were analyzed. RESULTS: All 12 aSAH patients underwent cSCS electrode implantation immediately after securing the aneurysm. Patients were stimulated for 10-14 consecutive days starting within 3 days of aneurysm rupture. Angiographic vasospasm occurred in six patients; two patients developed new vasospasm-related neurological symptoms; both recovered completely by discharge time. One patient died from unrelated multi-system failure; the rest were followed up clinically (average, 7.5 years; range, 12-151 months) and angiographically (average, 6.5 years; range, 36-125 months). No delayed ischemic neurological deficits/strokes and no cSCS-related adverse effects were observed. CONCLUSIONS: Our short- and long-term data suggest that cSCS is feasible and safe for patients in the acute aSAH settings. Small size of the patient cohort and lack of control do not allow us to conclude whether cSCS is able to prevent cerebral vasospasm, decrease its severity, and improve clinical outcomes in aSAH patients. However, our findings support further clinical trials and development of cSCS as a new concept to prevent and treat cerebral vasospasm. CLINICALTRIALS: gov NCT00766844, posted on 10/06/2008.

Nucleus Accumbens as a Novel Target for Deep Brain Stimulation in the Treatment of Addiction: A Hypothesis on the Neurochemical and Morphological Basis.

Addiction is a major cause of mortality and morbidity. Apart from psychotropic substances, alcohol and nicotine remain the common addictive materials responsible for the majority of deaths. Conventional conservative therapies are beneficial to certain populations, but the majority may require interventional treatments such as deep brain stimulation (DBS) in view of increasing mortality from drug abuse in recent years. We present a brief review on a novel neuromodulation target of the nucleus accumbens (NA) and its promising role in the management of addiction. The three stages of the addiction cycle are known to be mediated by dopaminergic pathways located in the mesolimbic dopamine system with connections to dorsal striatum, extended amygdala, cingulate gyrus, orbitofrontal cortex, prefrontal cortex, and ventral tegmental area. Recent advanced neuroimaging in humans and several animal studies demonstrated NA to be a vital anatomical area modulating this network. DBS of NA in animals reduced addictive behavior to alcohol, cocaine, and other narcotics significantly. The accidental observation that DBS of NA for psychiatric illnesses induced relief from addiction to alcohol and smoking has encouraged further research of late. Bilateral NA ablative surgery had shown nonrelapse in more than 50% of cases. Small series of patients have benefited so far from DBS of NA, but larger numbers are required to provide evidence-based treatment. The modulation of dopaminergic pathways through DBS of NA as a valid treatment for addiction is substantiated extensively by animal studies and also in a few clinical studies. However, this needs to be validated by a well-structured, multicenter controlled study in a large group of patients suffering from substance abuse.

Sanger Brown and Edward Schäfer before Heinrich Klüver and Paul Bucy: their observations on bilateral temporal lobe ablations.

Fifty years before a report on the complete bitemporal lobectomy syndrome in primates, known as the Klüver-Bucy syndrome, was published, 2 talented investigators working at the University College in London, England-neurologist Sanger Brown and physiologist Edward Schäfer-also made this discovery. The title of their work was "An investigation into the functions of the occipital and temporal lobes of the monkey's brain," and it involved excisional brain surgery in 12 monkeys. They were particularly interested in the then-disputed primary cortical locations relating to vision and hearing. However, following extensive bilateral temporal lobe excisions in 2 monkeys, they noted peculiar behavior including apparent loss of memory and intelligence resembling "idiocy." These investigators recognized most of the behavioral findings that later came to be known as the Klüver-Bucy syndrome. However, they were working within the late-19th-century framework of cerebral cortical localizations of basic motor and sensory functions. Details of the Brown and Schäfer study and a glimpse of the neurological thinking of that period is presented. In the decades following the pivotal work of Klüver and Bucy in the late 1930s, in which they used a more advanced neurosurgical technique, tools of behavioral observations, and analysis of brain sections after euthanasia, investigators have elaborated the full components of the clinical syndrome and the extent of their resections. Other neuroscientists sought to isolate and determine the specific temporal neocortical, medial temporal, and deep limbic structures responsible for various visual and complex behavioral deficits. No doubt, Klüver and Bucy's contribution led to a great expansion in attention given to the limbic system's role in action, perception, emotion, and affect-a tide that continues to the present time.

Quantifying sulcal and gyral topography in relation to deep seated and ventricular lesions: cadaveric study for basing surgical approaches and review of literature.

OBJECTIVE: Numerical implication of sulcal and gyral topography for surgical approaches has not been studied. METHODS: Percentage gain of distance using sulci as compared to that of gyri was calculated by measuring distances toward the ventricles in 15 hemispheres. RESULTS: Superior frontal sulcus was closest proving greater than 50% gain in distance compared to superior frontal gyrus; inferior temporal sulcus provided greater gain in the temporal lobe. CONCLUSION: Sulci provide upto 58% distance gain. For trans-gyral approaches, MFG and ITG were found closer to the respective ventricular area.

Radio-anatomic measurements and statistical generation of a safe surgical corridor to enter the ventricular trigone while avoiding injury to the optic radiations.

OBJECTIVE: To find a safe operative corridor to the ventricular trigone avoiding injury to the optic radiations (ORs). METHODS: In 24 adult hemispheres, dimensions of the atrium, height of the OR, and the cortex-to-atrium distance were measured. Superior parietal lobule (SPL), parieto-occipital sulcus (POS), and middle temporal gyrus (MTG) traced approaches were used to measure maximum safe angles to enter the atrium without traversing the OR. A statistical algorithm was generated using these measurements to predict the height of the OR and safe angles from measurements from MR imaging of five test hemispheres. Statistically calculated angles were compared with measured angles from dissection. RESULTS: Mean length and height of atrium, height of OR, and cortico-atrium distances were 2.07 cm, 3.36 cm, 2.53 cm, and 4.11 cm, respectively. The height of the atrium influenced the height of the OR significantly (p < 0.0001). The height of the dilated and small atrium was > 4.5 cm (> 95th percentile) and < 2 cm (< 5th percentile), respectively. For the SPL approach, the mean sagittal angle was 15.75 to 41.04 degrees; the mean coronal angle was - 17.08 to 14.92 degrees. For the POS approach, the mean sagittal angle was 51.29 to 70.1 degrees; the mean coronal angle was -8.63 to 17.22 degrees. Mean calculated height (statistically) of the OR was 0.29 mm above the mean observed height (dissection). The calculated angles and observed angles were very similar when tested for a variability of ± 2 degrees. CONCLUSION: The height of the normal atrium was 2.58 cm (height of atrium to height of OR ratio was 1:0.76). An operative corridor to the atrium without damaging the OR can be calculated from MR imaging of the brain.

Frontolateral pins for halo ring placement: reassessment of a common neurosurgical procedure with CT measurements of skull thickness.

OBJECT: Halo orthosis placement is a common neurosurgical procedure for the treatment of cervical spine injuries. Frontal sinus puncture by the anterior pins may occur using standard techniques, and up to 30% are dissatisfied with forehead scarring, especially women and African Americans. METHODS: The authors describe a frontolateral (FL) anterior pin site placement supported by high-resolution CT scan skull thickness measurements. The standard supraorbital (SO) pin site is several centimeters above the lateral orbit, whereas the FL pin site is 2-3 cm posterolateral to the SO site. Frontolateral placement is just anterior to the temporalis muscle close to a triangular anterior projection of the temporal hairline. For quantitative information on skull thickness at the SO and FT pin sites, thin 0.625-mm CT scan measurements of the outer table, diploic space, and inner table were obtained in 40 adults (80 sites). RESULTS: The mean values for total skull thickness at the SO and FT sites were not significantly different. The inner table was significantly thicker at the FL site in both males and females, buttressed by the nearby greater sphenoid wing. The mean total skull thickness was significantly less in females than in males, but the values were not significantly different at the SO and FL sites. CONCLUSIONS: The FL and SO anterior pin sites are comparable with respect to skull thickness CT measurements, with a significantly thicker inner table at the FL site. In the senior author's experience, the FL anterior pin site yielded secure fixation without skull perforation, neurovascular injury, or propensity to infection. The cosmetic result of the FL site is more acceptable, and the authors recommend its general usage be adopted.

Chronic epilepsy due to low grade temporal lobe tumors and due to hippocampal sclerosis: do they differ in post-surgical outcome?

Chronic seizures as a presenting feature of low grade temporal lobe gliomas and hippocampal sclerosis (HS) are reported to have similar outcomes although the prognostic indicators may not be the same. This study seeks to identify the variables that are associated with poor surgical outcome in both conditions. A retrospective analysis from our epilepsy data base was performed. All low-grade temporal lobe gliomas were selected and relevant variables were compared to the same variables in HS patients. There were 34 tumors (out of 233 cases of chronic temporal lobe epilepsy = 14.6 %) with a mean age of onset of 19 years, and the preoperative duration was 12.3 years. When compared to 120 HS patients both of these factors were significantly different (p < 0.001). Age at the time of surgery for tumors was 31.08 (p = 0.5). Tumors were left sided in 20 patients. In tumor cases amygdala resection was complete in 75 %, for hippocampus 24 % were complete and 39 % partial. Astrocytoma, ganglioglioma and oligodendroglioma constituted 80 % of tumor cases. Good outcome (Engel's Class I) was achieved in 88.2 % of tumor cases and 71 % of HS cases while poor outcome (Class III + IV) was seen in 5.9 and 16.7 % respectively. The follow up period for the two groups was not significantly different. In multivariate logistic regression analysis, the groups differed significantly in preoperative delay (between diagnosis and surgery) and in epilepsy outcome. Chronic temporal lobe epilepsy due to low-grade tumors had significantly better surgical outcome with considerably less preoperative delay. The age of onset of seizures was younger in HS patients but a delay in surgical treatment was significantly longer. Given that the diagnosis of treatment-resistant TLE secondary to HS can be established after two failed AED trials at optimal doses, shortening the interval between diagnosis and surgery may improve epilepsy outcome.

The need in dural graft suturing in Chiari I malformation decompression: A prospective, single-blind, randomized trial comparing sutured and sutureless duraplasty materials.

BACKGROUND: This study compared the use of two commonly utilized dural closure techniques used in augmentation duraplasty for Chiari malformation I (CM I) and evaluated their efficacy and outcome in terms of quality of life assessments. METHODS: This prospective randomized study compared sutureless (DuraGen) and suturable (Dura-Guard) techniques in CM I decompression. Clinical parameters, cost analysis, and SF-36 Quality of Life Questionnaire (QLQ) were utilized to assess outcome. RESULTS: Thirty-four patients were enrolled. Average age was 38.7 ± 12.2 years (mean ± SD (Standard Deviation)) and 82% of patients were female. Sixteen patients received DuraGen and 18 Dura-Guard. Age and gender were similar among groups. Postoperative complications did not differ between groups. Operative cost and time were less for DuraGen, whereas hospital stay was less with Dura-Guard, neither was statistically significant. Average QLQ scores at months 1, 2, and 3 improved in both groups. Dura-Guard patients showed greater improvement in quality of life at month 2 (P < 0.05) but groups did not differ at final survey. All patient's physical health (P < 0.005) and function (P < 0.005) were significantly improved. Outcome did not differ between groups and all patients showed significant improvement (P < 0.05). CONCLUSION: Both techniques are effective in reaching the goals of decompressive surgery for CM I and did not differ in quality of life at final survey. All patients showed significant improvement in physical function, physical health, and outcome following surgery. With all variables being equal the choice of duraplasty material may be based upon surgeon's preference.

Temporal lobe gangliogliomas associated with chronic epilepsy: long-term surgical outcomes.

OBJECTIVE: To review the clinical features and surgical outcome in patients with temporal lobe gangliogliomas associated with intractable chronic epilepsy. METHODS: The Rush University Surgical Epilepsy Database was queried to identify patients with chronic intractable epilepsy who underwent resection of temporal lobe gangliogliomas at Rush University Medical Center. Medical records were reviewed for age of seizure onset, delay to referral for surgery, seizure frequency and characteristics, pre-operative MRI results, extent of resection, pathological diagnosis, complications, length of follow-up, and seizure improvement. RESULTS: Fifteen patients were identified. Average duration between seizure onset and surgery was 14.3 years. Complex partial seizures were the most common presenting symptom. Detailed operative data was available for 11 patients - of these, 90.9% underwent complete resection of the amygdala and either partial or complete resection of the hippocampus, in addition to lesionectomy. Average follow-up was 10.4 years (range 1.6-27.5 years), with 14 patients improving to Engel's class I and one patient to Engel's class III. There were no recurrences, and permanent complications were noted in one patient. CONCLUSIONS: Long-term follow-up of patients with temporal lobe gangliogliomas associated with chronic intractable epilepsy demonstrates excellent results in seizure improvement with surgery and increasingly low incidence of complications with improvements in microsurgical techniques.

Modified brainstem auditory evoked responses in patients with non-brainstem compressive cerebral lesions.

The brainstem auditory evoked response (BAER) is sensitive to pontomesencephalic integrity, transtentorial brain herniation, and at times increased intracranial pressure (ICP). The authors report their experience utilizing a recently described rapid rate, binaural, click and 1,000-Hz tone-burst modification of the BAER (MBAER) in 22 symptomatic non-trauma patients with non-brainstem compressive space-taking cerebral lesions. The majority presented with mild to moderate clinical signs suggestive of increased ICP, and focal neurological deficits. The cerebral lesions, mostly tumors (17), averaged 4-5 cm in diameter, with radiological signs of mass effect such as flattening of the sulci, midline shift, and narrowing of the basal cisterns. A number of significant changes in Wave V and V (n) latency and less so amplitude were found in patients compared with age-matched normal volunteers, as well as those again studied after surgical decompression. Similar MBAER changes had been noted in normal volunteers placed in a dependent head position. Possible mechanisms to explain these findings are discussed. The methodology shows promise and if combined with automated peak recognition could make Neuro ICU monitoring practical.

Frederic Gibbs and his contributions to epilepsy surgery and electroencephalography.

Frederic Gibbs' (1903-1992) long research career was devoted to the understanding and treatment of epileptic phenomena and closely associated with the development of electroencephalography (EEG). After medical school, he joined the Harvard Neurological Unit at Boston City Hospital directed by Stanley Cobb. In the early 1930s, Gibbs developed a thermoelectric blood flow probe and, with William Lennox, proved in animals and humans that a seizure increases cerebral blood flow. By 1934, Gibbs became a pioneer in the field of EEG while working at Harvard with Hallowell Davis and Lennox, and was the first to convincingly record and report EEG findings in epilepsy and states of altered consciousness. Several years later, Gibbs and Lennox were the first to recommend cerebral excisions in several patients with uncontrolled epilepsy based on EEG. Moving to the University of Illinois at Chicago in 1944, Gibbs founded a consultation clinic for epilepsy, performed the first EEG depth recordings using pneumoencephalography-guided stereotaxy, and noted that sleep EEGs in patients with psychomotor seizures frequently disclosed temporal epileptic patterns. Gibbs convinced Percival Bailey to collaborate on patients with refractory temporal lobe psychomotor seizures without tumors. In 1947, the first nonlesional temporal lobe excisions based on EEG localization were performed in these patients, and, by 1948, anterior temporal lobectomy had become their procedure of choice. Gibbs and Lennox received the coveted Lasker Award among other honors as pioneers in establishing the modern era of epilepsy diagnosis and treatment.

A novel method of identifying the internal acoustic canal in the middle fossa approach in a cadaveric study-the rule of 2s.

Objective Multiple landmarks and anatomic relationships exist to identify internal acoustic canal (IAC) in middle fossa approach for removing intracanalicular schwannomas. We attempted to identify a reproducible, practical method to quickly identify the IAC that would be applicable when an expanded middle fossa approach is required. Design Middle fossa approach was performed on 10 cadavers (21 dissections). In the first head, temporal and suboccipital craniotomies were performed to identify landmarks and formulate a hypothesis. Porous acusticus (PA) was identified and IAC was circumferentially skeletonized into middle fossa. Orientation of IAC in the middle fossa was evaluated in relation to foramen spinosum (FS), foramen ovale (FO), petrous ridge, and petrous apex. Consistency of this relationship was tested in the remaining heads. Results The opening of PA (point A) was consistently found at a mean of 2.38 cm posterolateral to the petrous apex along the petrous ridge (range 2.1 to 2.8). A line was drawn from the FO to FS and extrapolated posteriorly. The IAC (point B) was found a mean distance of 2.39 cm from FS along the FS-FO line (range 2.1 to 2.8). The course of IAC was consistently found by connecting point A to point B. Conclusion A novel, practical, and reproducible method is described to identify the IAC via the expanded middle fossa approach.

Repositioning of supraorbital nerve stimulation electrode using retrograde needle insertion: a technical note.

INTRODUCTION: With growing interest and acceptance of peripheral nerve stimulation (PNS) approach, there is now an increasing need in developing clear procedural details to resolve frequent complications and minimize associated tissue injury. Migration and suboptimal positioning of PNS electrodes are one of the most commonly observed complications of PNS approach. MATERIALS AND METHODS: We present a simple technique for repositioning a supraorbital electrode using retrograde insertion of introducer needle that allows one to place percutaneous (cylindrical) PNS electrode into appropriate anatomical location with minimal additional injury to surrounding tissues. RESULTS: This approach has been successfully used in multiple cases. An illustrative case of electrode revision with proposed technique is described in detail. CONCLUSION: This technically simple approach to repositioning of cylindrical supraorbital electrodes using retrograde needle insertion eliminates the need for a more elaborate and invasive procedure. The technique can be used for electrode repositioning in most PNS applications.

The use of bioabsorbable screws to fix Type II odontoid fractures: a biomechanical study.

OBJECT: Anterior screw fixation of the Type II odontoid fracture stabilizes the odontoid without restricting the motion of the cervical spine. The metal screw may limit bone remodeling because of stress shielding (if not placed properly) and limit imaging of the fracture. The use of bioabsorbable screws can overcome such shortcomings of the metal screws. The purpose of this study was to compare the strength of a 5-mm bioabsorbable screw with single 4-mm metal and double 3.5-mm lag screw fixation for Type II fractures of the odontoid process. METHODS: Three different modalities of anterior screw fixation were used in 19 C-2 vertebrae. These fixation methods consisted of a single 5-mm cannulated bioabsorbable lag screw (Group A), a single 4-mm cannulated titanium lag screw (Group B), and two 3.5-mm cannulated titanium lag screws (Group C). Anteroposterior (AP) stiffness and rotational stiffness were evaluated in all constructs. RESULTS: There was no statistical difference among the ages of the cadavers in each group (p = 0.52). The AP bending stiffness in Groups A, B, and C was 117 ± 86, 66 ± 43, and 305 ± 130 Nm/mm, respectively. The AP bending stiffness in Group C was significantly higher than that in Groups A and B (p = 0.01 and p = 0.001, respectively). The difference in AP bending stiffness values of bioabsorbable and 4-mm metal screws was not statistically significant (p = 0.23). The rotational stiffness of the double 3.5-mm metal screws was significantly greater than that of the 5-mm bioabsorbable and the 4-mm titanium screws. CONCLUSIONS: Double screw fixation with 3.5-mm screws provides the stiffest construct in Type II odontoid fractures. Bioabsorbable lag screws (5 mm) have the same AP bending and rotational stiffness as the single titanium lag screw (4 mm) in odontoid fractures.

Spinal cord stimulation: Current applications for treatment of chronic pain.

Spinal cord stimulation (SCS) is thought to relieve chronic intractable pain by stimulating nerve fibers in the spinal cord. The resulting impulses in the fibers may inhibit the conduction of pain signals to the brain, according to the pain gate theory proposed by Melzack and Wall in 1965 and the sensation of pain is thus blocked. Although SCS may reduce pain, it will not eliminate it. After a period of concern about safety and efficacy, SCS is now regaining popularity among pain specialists for the treatment of chronic pain. The sympatholytic effect of SCS is one of its most interesting therapeutic properties. This effect is considered responsible for the effectiveness of SCS in peripheral ischemia, and at least some cases of complex regional pain syndrome. The sympatholytic effect has also been considered part of the management of other chronic pain states such as failed back surgery syndrome, phantom pain, diabetic neuropathy, and postherpetic neuralgia. In general, SCS is part of an overall treatment strategy and is used only after the more conservative treatments have failed. The concept of SCS has evolved rapidly following the technological advances that have produced leads with multiple contact electrodes and battery systems. The current prevalence of patients with chronic pain requiring treatment other than conventional medical management has significantly increased and so has been the need for SCS. With the cost benefit analysis showing significant support for SCS, it may be appropriate to offer this as an effective alternative treatment for these patients.