Microstructural alterations of major thalamic nuclei in the chronic pediatric spinal cord injured population.

Background: The brain undergoes reorganization following spinal cord injury (SCI), but little is known about how the thalamus is affected in pediatric SCIs. Purpose: To characterize microstructural alterations in the thalamus after SCI with diffusion tensor imaging (DTI) metrics. Methods: 18 pediatric participants with chronic SCI (8-20 years) were stratified using the American Spinal Injury Association Impairment Scale (AIS) into groups: A, B, and C/D. DTI of the brain used a 3 T Siemens Verio MRI using the parameters: 20 directions, number of averages = 3, b = 1000 s/mm2, voxel size = 1.8 mm × 1.8 mm, slice thickness = 5 mm, TE = 95 ms, TR = 4300 ms, 30 slices, FOV = 230 × 230 mm2, matrix = 128 × 128, acquisition time = 4:45 min. Diffusion data was processed to generate DTI metrics FA, MD, AD, and RD. Data analysis: DTI metrics were acquired by superimposing the AAL3 thalamic atlas onto participant diffusion images registered to MNI152 space. We utilized a multiple Mann-Whitney U-test to compare between AIS groups, considering values of p ≤ 0.05 as significant. Results: FA, AD, RD, and MD significantly differed in thalamic nuclei between AIS groups A vs B and B vs C/D. Significant nuclei include the right ventral anterior, left intralaminar, bilateral lateral pulvinar, and right lateral geniculate. Conclusion: Our findings suggest the presence of microstructural alterations based on SCI severity in pediatric patients. These results are encouraging and warrant further study.

Widespread theta synchrony and high-frequency desynchronization underlies enhanced cognition.

The idea that synchronous neural activity underlies cognition has driven an extensive body of research in human and animal neuroscience. Yet, insufficient data on intracranial electrical connectivity has precluded a direct test of this hypothesis in a whole-brain setting. Through the lens of memory encoding and retrieval processes, we construct whole-brain connectivity maps of fast gamma (30-100 Hz) and slow theta (3-8 Hz) spectral neural activity, based on data from 294 neurosurgical patients fitted with indwelling electrodes. Here we report that gamma networks desynchronize and theta networks synchronize during encoding and retrieval. Furthermore, for nearly all brain regions we studied, gamma power rises as that region desynchronizes with gamma activity elsewhere in the brain, establishing gamma as a largely asynchronous phenomenon. The abundant phenomenon of theta synchrony is positively correlated with a brain region's gamma power, suggesting a predominant low-frequency mechanism for inter-regional communication.

[Retrospective analysis of dental trauma among soldiers in the Israel Defense Forces].

OBJECTIVE: Determination of the incidence, types and causes of traumatic dental incidents (TDIs) among Israel Defense Forces (IDF) soldiers. STUDY DESIGN: Dental trauma reports from all active IDF dental clinics between the years 2000-2010 were analyzed. A total of 1671 dental trauma reports were classified according to the incidence, causes and etiologies of the injuries, the number and type of traumatized teeth, and the types of dental injuries. Statistical associations between the number of trauma cases and gender, type of training of the soldier, and the month during which the injury occurred were analyzed. RESULTS: The incidence of dental injuries was 19.65 cases/10,000 soldiers/year. In basic training bases, 75.49 dental trauma cases/10,000 soldiers/year were found in comparison to 14.28 cases in all other bases. Male soldiers were 4.24 times more prone to dental injuries than female soldiers. Significantly more trauma cases occurred during the months of January and August (rate ratio 1.39 and 1.33 respectively), and significantly fewer cases occurred in July (rate ratio 0.59). The most frequent circumstances of TDIs were military training and work related injuries (29.5% and 15% respectively). The etiology of 56.3% of the injuries was trauma from blunt objects that are not a weapon. Of the injuries, 34.9% occurred as a result of trauma from the personal weapon of the soldier. Most trauma cases involved one or two injured teeth (73.2% and 20.1% respectively). Of the trauma cases, 33.8% involved the right maxillary central incisor and 32.5% involved the left maxillary central incisor. There was no significant difference between injuries on the right or left side. The most frequent type of dental injury was a crown fracture (72.8%). CONCLUSION: The risk factors for dental trauma found in this study were male soldiers during basic training in the months of January and August. Most TDIs resulted from blunt objects including personal weapons. Crown fracture was the most frequent type of injury.

A comparison of occipital and temporal lobe epilepsies.

PURPOSE: Differentiating between occipital lobe epilepsy (OLE) and temporal lobe epilepsy (TLE) is often challenging. This retrospective case-control study compares OLE to TLE and explores markers that suggest the diagnosis of OLE. METHODS: We queried the Jefferson Epilepsy Center surgery database for patients who underwent a resection that involved the occipital lobe. For each patient with OLE, three sequential case-control patients with TLE were matched. Demographic characteristics, symptoms, electrophysiological findings, imaging findings, and surgical outcome were compared. RESULTS: Nineteen patients with OLE and 57 patients with TLE were included in the study. Visual symptoms were unique to patients with OLE (8/19) and were not reported by patients with TLE (P < 0.0001). Occipital interictal spikes (IIS) were found only in one-third of the patients with OLE (6/19) and in no patients with TLE (P < 0.0001). IIS in the posterior temporal lobe were found in five of 19 patients with OLE vs one of 57 patients with TLE (P = 0.003). IIS involved more than one lobe of the brain in most patients with OLE (11/19) but only in nine of 57 the TLE group. (P = 0.0003) Multilobar resection was needed in most patients with OLE (15/19), typically including the temporal lobe, but in only one of the patients with TLE (P < 0.0001). CONCLUSION: Occipital lobe epilepsy is difficult to identify and may masquerade as temporal lobe epilepsy. Visual symptoms and occipital findings in the EEG suggest the diagnosis of OLE, but absence of these features, does not exclude the diagnosis. When posterior temporal EEG findings or multilobar involvement occurs, the diagnosis of OLE should be considered.

Methods for implantation of micro-wire bundles and optimization of single/multi-unit recordings from human mesial temporal lobe.

OBJECTIVE: The authors report methods developed for the implantation of micro-wire bundles into mesial temporal lobe structures and subsequent single neuron recording in epileptic patients undergoing in-patient diagnostic monitoring. This is done with the intention of lowering the perceived barriers to routine single neuron recording from deep brain structures in the clinical setting. APPROACH: Over a 15 month period, 11 patients were implanted with platinum micro-wire bundles into mesial temporal structures. Protocols were developed for (A) monitoring electrode integrity through impedance testing, (B) ensuring continuous 24-7 recording, (C) localizing micro-wire position and 'splay' pattern and (D) monitoring grounding and referencing to maintain the quality of recordings. MAIN RESULTS: Five common modes of failure were identified: (1) broken micro-wires from acute tensile force, (2) broken micro-wires from cyclic fatigue at stress points, (3) poor in vivo micro-electrode separation, (4) motion artifact and (5) deteriorating ground connection and subsequent drop in common mode noise rejection. Single neurons have been observed up to 14 days post-implantation and on 40% of micro-wires. SIGNIFICANCE: Long-term success requires detailed review of each implant by both the clinical and research teams to identify failure modes, and appropriate refinement of techniques while moving forward. This approach leads to reliable unit recordings without prolonging operative times, which will help increase the availability and clinical viability of human single neuron data.

A review on spinal cord stimulation.

Spinal cord stimulation has evolved since its inception. It has been used as a treatment option since 1967 with a concentration on chronic pain syndromes. This review will focus on reviewing the literature and the most recent publications, as well as a focus on the advancements in technology. The most common indications will be discussed as well as psychological screening, trials, implantation technique, and programming. Focused attention is on evolving technology and the direction of the field. This focus leans on the technology to keep pace with the evolving clinical needs.

Enhancement of ferroelectricity in strained BaTiO3 thin films.

Biaxial compressive strain has been used to markedly enhance the ferroelectric properties of BaTiO3 thin films. This strain, imposed by coherent epitaxy, can result in a ferroelectric transition temperature nearly 500 degrees C higher and a remanent polarization at least 250% higher than bulk BaTiO3 single crystals. This work demonstrates a route to a lead-free ferroelectric for nonvolatile memories and electro-optic devices.

MR safety in patients with implanted deep brain stimulation systems (DBS).

INTRODUCTION: While it is desirable to perform MRI examinations in patients with deep brain stimulators (DBS), a major safety concern exists regarding the potential for excessive heating secondary to magnetically induced electrical currents. This study was designed to determine the safety of MRI and DBS. METHODS: Standard configurations of DBS systems were tested. In vitro testing was performed using a 1.5-Tesla MR system, a gel-filled phantom, and the body and head RF coils with varying levels of RF energy (SAR). A fluoroptic thermometry system was used to record temperatures. RESULTS: Using the 1.5-T MRI and body RF transmit coil, the temperature changes ranged from 2.5 to 25.3 degrees C. Using the 1.5-T MRI and head RF transmit coil, the temperature changes ranged from 2.3 to 7.1 degrees C. CONCLUSIONS: Excessive heating does occur with certain MR imaging conditions. Under certain conditions determined in this study, patients with DBS may safely undergo anatomical MR imaging. In the future, standardized testing and more comprehensive studies will be needed to ensure the MR safety of neurostimulation systems.

Prevention of carotid angioplasty-induced bradycardia and hypotension with temporary venous pacemakers.

OBJECTIVE: Carotid angioplasty with stent placement is becoming an established treatment modality for patients with high-risk carotid stenosis. Unlike carotid endarterectomy, angioplasty causes direct mechanical dilation of the stenotic carotid artery and bulb. Stimulation of the sinus baroreceptors induces a reflexive response that consists of increased parasympathetic discharge and inhibition of sympathetic tone, which results in bradycardia and subsequent cardiogenic hypotension. METHODS: At a single institution, the experience with 43 patients treated from November 1994 to January 2000 with 47 angioplasty and stent procedures for occlusive carotid artery disease was retrospectively reviewed. Prophylactic temporary venous pacemakers were used to prevent hypotension from possible angioplasty-induced bradycardia. Pacemakers were set to capture a heart rate decrease below 60 beats per minute. Variables analyzed included demographics, etiology of disease, side of the lesion, the presence of symptoms, history of coronary artery disease, percent stenosis, type of stent used, number of dilations, pressure of dilation, and angioplasty balloon diameter. RESULTS: Ten patients were excluded because pacemakers were not used during their angioplasty procedures, and these included three emergencies and a lesion that was unrelated anatomically to the carotid sinus (petrous carotid). The remaining 37 procedures were performed in 33 patients with a mean age of 67 years, and consisted of 17 men, 16 women, 20 right and 17 left-sided lesions. The pacemakers maintained a cardiac rhythm in 23 (62%) of the 37 procedures and in no case did the pacemaker fail to respond when activated. Recurrent (56%; 10 of 18), radiation-induced (78%; 7 of 9), and medically refractory carotid stenosis (67%; 6 of 9) required intraprocedural pacing. Two patients with recurrent stenosis became hypotensive despite the aid of the pacing device but were not symptomatic. Seventy-nine percent (15 of 19) of symptomatic lesions and 57% (8 of 14) of nonsymptomatic lesions required pacing, which was statistically significant (P = 0.049). No patient experienced an operative morbidity or mortality as a consequence of the temporary pacing devices. CONCLUSION: Angioplasty-induced bradycardia is a common condition, and it is more prevalent in radiation-induced stenosis and with symptomatic lesions. Temporary venous demand pacing is a safe procedure and may prevent life-threatening, baroreceptor-induced hypotension.

The cause of neurologic deterioration after acute cervical spinal cord injury.

STUDY DESIGN: A retrospective review was performed to identify patients at risk for secondary neurologic deterioration after complete cervical spinal cord injury. OBJECTIVE: To examine the causes of early neurologic deterioration in patients with complete spinal cord injury at a regional spinal cord injury center. SUMMARY OF BACKGROUND DATA: After complete spinal cord injury, neurologic deterioration occurs in a subgroup of patients. Despite anecdotal reports, no study has clearly identified the subgroups at highest risks. METHODS: One hundred eighty-two patients with complete spinal cord injury were identified among 1904 consecutive patients with acute spinal trauma evaluated from March 1993 through September 1999. Parameters analyzed included demographics, mechanism of injury, American Spinal Cord Injury Association (ASIA) level on admission and during hospital stay, onset of ascension, blood pressure, hemoglobin, febrile episode, heparin administration, and the timing of operation and traction. Radiographs of patients with ascending complete spinal cord injury were reviewed with attention to fracture type and neurologic and vascular injuries. RESULTS: Twelve of 186 patients with ASIA Grade A (6.0%) complete spinal cord injury had neurologic deterioration during the first 30 days after injury. No patients with penetrating injuries had deterioration. A significant association between death and ascension was observed. The onset of ascension of the injury could be categorized into three discrete temporal subsets. Early deterioration (less than 24 hours) was typically related to traction and immobilization. Delayed deterioration (between 24 hours and 7 days) was associated with sustained hypotension in patients with fracture dislocations. Late deterioration (more than 7 days) was observed in a patient with vertebral artery injuries. CONCLUSION: Delayed neurologic deterioration in complete spinal cord injury (ASIA A) is not rare. Specific causes were identified among discrete temporal subgroups. Management of complete spinal cord injury can be improved with recognition of these temporal patterns and earlier intervention.

Single-stage autogenous bone grafting and internal fixation in the surgical management of pyogenic discitis and vertebral osteomyelitis.

OBJECT: Patients with deep wound infections complicating previously placed internal instrumentation have been successfully treated by debridement and prolonged postoperative antibiotic therapy, which avoided removal of the hardware. Comparatively fewer patients with pyogenic discitis and vertebral osteomyelitis (PDVO) have undergone single-stage debridement, arthrodesis, and internal fixation. The purpose of this study was to determine the efficacy of combining debridement, arthrodesis in which iliac autograft is used, and segmental internal fixation in a single-stage procedure for patients in whom nonoperative management of PDVO has failed. METHODS: A retrospective analysis of 17 consecutive patients with PDVO treated between July 1996 and September 1999 was performed. Follow-up data (mean 30 months) included office examinations and telephone interviews, and patients were grouped according to the duration of preoperative antibiotic therapy. All patients experienced significant postoperative reduction in pain, and those with neurological deficits improved. Eleven patients were independently ambulatory, and three required a walker; only five had been ambulating independently preoperatively. Two patients died during the 1st postoperative week of medical complications; another developed a wound dehiscence that was managed with debridement, prolonged antibiotic administration, and removal of the hardware 1 year later. In no case was pseudarthrosis demonstrated on dynamic radiography. Most patients received only a 6-week course of intravenous antibiotics postoperatively. CONCLUSIONS: The authors conclude that single-stage debridement, arthrodesis, and internal fixation can be effective in the treatment of PDVO. A 6-week course of postoperative intravenous antibiotics may be sufficient in patients with few risk factors. The harvesting of iliac autograft through the same operative exposure may not increase the risk of secondary infection.

A review of size and location of ruptured intracranial aneurysms.

OBJECTIVE: To review our experience and examine the size at which aneurysms ruptured in our patient population. METHODS: Patient charts and angiograms for all patients admitted with a diagnosis of subarachnoid hemorrhage to the Thomas Jefferson/Wills Eye Hospital between April 1996 and March 2000 were reviewed. RESULTS: Of the 362 cases reviewed, definite measurements of the ruptured aneurysm were obtained in 245. The data clearly showed that most ruptured aneurysms presenting to our institution were less than 10 mm in diameter. We found that, regardless of location on the circle of Willis, 85.6% of all aneurysms presenting with rupture were less than 10 mm. Review by location shows that aneurysms of the anterior communicating artery most often presented with rupture at sizes less than 10 mm (94.4%). A large number of ruptured posterior communicating artery aneurysms also presented at sizes less than 10 mm (87.5%). This trend continued for all aneurysm sites in our review. The incidence of subarachnoid hemorrhage in Western countries is estimated at 10 per 100,000 people per year. Recent reports have indicated that aneurysms less than 10 mm in size are unlikely to rupture. CONCLUSION: We argue that the risk of small aneurysms rupturing is not insignificant, especially those of the anterior communicating artery. Our findings indicate that surgery on unruptured aneurysms should not be predicated on aneurysm size alone.

Epidural spinal cord stimulation with a multiple electrode paddle lead is effective in treating intractable low back pain.

The objective of this paper is to examine the outcomes of patients with intractable low-back pain treated with epidural spinal cord stimulation (SCS) utilizing paddle electrodes and a radio frequency (RF) stimulator. A multicenter prospective study was performed to collect data from patients suffering from chronic low-back pain. The study was designed to collect data from 60 patients at four centers and examine their outcomes at, or up to two years post implantation. Patients' participation included written responses to a series of preoperative questionnaires that were designed to collect previous surgical history information, leg and low back pain characteristics, and routine demographic information. Outcome measurements included the visual analog scale (VAS), the Oswestry Disability Questionnaire, the Sickness Impact Profile (SIP), and a patient satisfaction rating scale. Data were collected at each site during patient visits or by mail, at approximately six months, 12 months, and 24 months. A total of 44 patients have been implanted with a SCS system at the time of this writing. Follow-up data were available for 41 patients. Preoperatively, all patients reported more than 50% of their pain in the low back. All patients had pain in both their backs and legs. All patients showed a reported mean decrease in their 10-point VAS scores compared to baseline. The majority of patients reported fair to excellent pain relief in both the low back and legs. At six months 91.6% of the patients reported fair to excellent relief in the legs and 82.7% of the patients reported fair to excellent relief in the low back. At one year 88.2% of the patients reported fair to excellent relief in the legs and 68.8% of the patients reported fair to excellent relief in the low back. Significant improvement in function and quality of life was found at both the six-month and one-year follow-ups using the Oswestry and SIP, respectively. The majority of patients reported that the procedure was worthwhile (92% at six months, 88% at one year). No patient indicated that the procedure was not worthwhile. We conclude that SCS proved beneficial at one year for the treatment of patients with chronic low back and leg pain.

Internet resources for spine surgeons.

To classify web sites on common spinal disorders as to their utility for the spine surgeon and patient. Five common spinal disorders were used to generate lists of relevant sites. These sites were categorized as to their relevance for patients and surgeons, their sponsoring organization, and their comprehensiveness. A total of 56,249 web sites were found using the five key words on five search engines. Using the "And" operator, a total of 227 web sites were generated. The majority of sites were patient oriented. Physician- or organization-sponsored sites were the most common. Ten sites were found to have comprehensive information for both patients and spine surgeons. Many web sites exist that discuss disorders of the spine. Currently there is not any one web site that contains comprehensive information for both the spine surgeon and patient.

Approaching the upper thoracic vertebrae without sternotomy or thoracotomy: a radiographic analysis with clinical application.

STUDY DESIGN: The distribution of the lowest vertebra tangential to the suprasternal notch and the lowest intervertebral disc visualized above the sternum was determined on magnetic resonance imaging (MRI) studies. The method is illustrated in seven patients undergoing upper thoracic spinal reconstruction to define a surgical approach without sternotomy or thoracotomy. OBJECTIVES: The relation of the sternal notch to thoracic vertebrae was examined by MRI to estimate the thoracic level approachable anteriorly without sternotomy. SUMMARY OF BACKGROUND DATA: Upper thoracic spine (T1-T4) visualization is considered difficult. The thoracic vertebrae that can be visualized anteriorly without sternotomy is unknown. METHODS: The vertebral level tangential to the suprasternal notch and the lowest intervertebral disc visualized in its entirety above the sternum was determined from 106 consecutive midsagittal cervicothoracic MRI studies. The method was evaluated in seven patients to illustrate application of a low suprasternal, lateral extracavitary, or transpedicular approach to performing upper thoracic reconstruction. RESULTS: The midportion of the T3 vertebra is often above the sternal notch, whereas the trajectory of the T1-T2 intervertebral disc is usually rostral to the sternum. All four patients with disease above the sternal notch on MRI underwent a low left suprasternal approach, whereas three others were treated with a lateral extracavitary or transpedicular approach. No patient worsened neurologically and all ambulated independently after surgery. CONCLUSIONS: Upper thoracic vertebrae can be exposed without sternotomy or thoracotomy by a low left suprasternal approach. Midsagittal cervicothoracic MRI can identify the thoracic vertebrae above the sternum, thereby determining whether a low suprasternal approach is feasible. Otherwise, a lateral extracavitary or transpedicular approach can be used to avoid sternotomy or thoracotomy.

Future trends in spinal cord stimulation.

Spinal cord stimulation (SCS) has been available for about 30 years, but only in the past five years has it met with widespread acceptance and recognition by the medical community. Traditionally performed by neurosurgeons, SCS is being increasingly utilized by anesthesiologists, orthopedic surgeons and physiatrists. Pain management continues to be the most widespread application of SCS. More sophisticated technology has allowed the implanters to successfully address more complex pain syndromes such as widespread reflex sympathetic dystrophy and the failed back syndrome. Other applications are being developed, combining the ability to stimulate the spinal cord, the nerve roots and the peripheral nerves. Examples include angina pectoris, urinary incontinence and occipital neuralgia. Computer-interactive programming is gaining popularity, especially due to the extreme complexity of the implanted stimulation devices. The ability to stimulate independently multiple channels as well as multiple arrays of electrodes is today a reality. This has increased greatly the efficacy, safety and reliability of the modality. In the future, SCS will undoubtedly move several steps up in the treatment ladder of chronic pain conditions, while new applications will be discovered. The future of neural implantable technologies is bright, with an increasingly important role in the medical management of chronic conditions affecting the nervous system.

Epidemiology of spinal cord injury after acute odontoid fractures.

OBJECT: Cervical spinal cord injury (SCI) after odontoid fracture is unusual. To identify predisposing factors, the authors evaluated a consecutive series of patients who sustained SCI from odontoid fractures. METHODS: A consecutive series of 5096 admissions to the Delaware Valley Regional Spinal Cord Injury Center were reviewed, and 126 patients with neurological impairment at the C1-3 levels were identified. Seventeen patients had acute closed odontoid fractures with neurological deficit. Various parameters including demographics, mechanisms of injury, associated injuries, fracture types/displacements, and radiographic cervical canal dimensions were compared between "complete" and "incomplete" spinal cord injured-patients as well as with neurologically intact patients who had suffered odontoid fractures. There were similar demographics, mechanisms of injury, associated injuries, fracture type/displacement, and canal dimensions in patients with complete and incomplete SCIs. However, only patients with complete injury were ventilator dependent. In comparison with patients with intact spinal cords, spinal cord-injured patients were more commonly males (p = 0.011) who had sustained higher velocity injuries (p = 0.027). The computerized tomography scans of 11 of 17 neurologically impaired patients were compared with those of a random sample of 11 patients with intact spinal cords. Although the anteroposterior diameter (p = 0.028) and cross-sectional area (p = 0.0004) of the cervical spinal canal at the C-2 level were smaller in impaired patients, the displacement of the fragment was not different. CONCLUSIONS: Odontoid fractures are an infrequent cause of SCI. Patients with these injuries typically are males who have smaller spinal canals and have sustained high velocity injuries.

Central nervous system tuberculosis: medical management and surgical indications.

BACKGROUND: An increase in the incidence of tuberculosis in industrialized nations has prompted a need for earlier diagnosis, treatment, and isolation of disease. An associated rise in the number of patients with central nervous system tuberculosis (CNS TB) has forced neurosurgical services to reevaluate the indications for operative intervention. METHODS: Seventeen cases of CNS TB were found in a retrospective review of all cases managed on the neurosurgical service between 1989 and 1994. These cases included eight with tuberculous meningitis, seven cases of supratentorial tuberculomas, and two cases of infratentorial tuberculomas. RESULTS: Major permanent neurologic morbidity was seen in one case (6%). Five patients (29.4%) died of complications associated with their primary disease. Eleven patients (64.6%) had excellent outcomes. All patients in the latter group completed an 18-month course of antituberculous therapy. Cerebrospinal fluid shunts were necessary in three cases and emergent craniotomy was performed in three cases. Only four cases had human immunodeficiency virus (HIV) coinfection. CONCLUSION: The neurosurgeon's role in the management of CNS TB has once again become more evident. In the present series it is unclear as to whether this is due to multiple drug-resistant strains of Mycobacterium tuberculosis or HIV coinfection. It is clear, however, that vigilance over patient compliance and serial neurologic evaluation will determine the need for operative intervention.