Thomas A. Bergman

A prospective, randomized clinical trial to compare the effect of hyperbaric to normobaric hyperoxia on cerebral metabolism, intracranial pressure, and oxygen toxicity in severe traumatic brain injury

OBJECT Oxygen delivered in supraphysiological amounts is currently under investigation as a therapy for severe traumatic brain injury (TBI). Hyperoxia can be delivered to the brain under normobaric as well as hyperbaric conditions. In this study the authors directly compare hyperbaric oxygen (HBO2) and normobaric hyperoxia (NBH) treatment effects. METHODS Sixty-nine patients who had sustained severe TBIs (mean Glasgow Coma Scale Score 5.8) were prospectively randomized to 1 of 3 groups within 24 hours of injury: 1) HBO2, 60 minutes of HBO(2) at 1.5 ATA; 2) NBH, 3 hours of 100% fraction of inspired oxygen at 1 ATA; and 3) control, standard care. Treatments occurred once every 24 hours for 3 consecutive days. Brain tissue PO(2), microdialysis, and intracranial pressure were continuously monitored. Cerebral blood flow (CBF), arteriovenous differences in oxygen, cerebral metabolic rate of oxygen (CMRO2), CSF lactate and F2-isoprostane concentrations, and bronchial alveolar lavage (BAL) fluid interleukin (IL)-8 and IL-6 assays were obtained pretreatment and 1 and 6 hours posttreatment. Mixed-effects linear modeling was used to statistically test differences among the treatment arms as well as changes from pretreatment to posttreatment. RESULTS In comparison with values in the control group, the brain tissue PO2 levels were significantly increased during treatment in both the HBO2 (mean +/- SEM, 223 +/- 29 mm Hg) and NBH (86 +/- 12 mm Hg) groups (p < 0.0001) and following HBO2 until the next treatment session (p = 0.003). Hyperbaric O2 significantly increased CBF and CMRO2 for 6 hours (p < or = 0.01). Cerebrospinal fluid lactate concentrations decreased posttreatment in both the HBO2 and NBH groups (p < 0.05). The dialysate lactate levels in patients who had received HBO2 decreased for 5 hours posttreatment (p = 0.017). Microdialysis lactate/pyruvate (L/P) ratios were significantly decreased posttreatment in both HBO2 and NBH groups (p < 0.05). Cerebral blood flow, CMRO2, microdialysate lactate, and the L/P ratio had significantly greater improvement when a brain tissue PO2 > or = 200 mm Hg was achieved during treatment (p < 0.01). Intracranial pressure was significantly lower after HBO2 until the next treatment session (p < 0.001) in comparison with levels in the control group. The treatment effect persisted over all 3 days. No increase was seen in the CSF F2-isoprostane levels, microdialysate glycerol, and BAL inflammatory markers, which were used to monitor potential O2 toxicity. CONCLUSIONS Hyperbaric O2 has a more robust posttreatment effect than NBH on oxidative cerebral metabolism related to its ability to produce a brain tissue PO2 > or = 200 mm Hg. However, it appears that O2 treatment for severe TBI is not an all or nothing phenomenon but represents a graduated effect. No signs of pulmonary or cerebral O2 toxicity were present.

3-Tesla intraoperative MR imaging for neurosurgery

SummaryIntraoperative magnetic resonance (MR) image-guided neurosurgery has been performed since 1994. Using a 1.5-Tesla (T) intraoperative MR imaging system, we have performed more than 750 interventional procedures. Having validated the safety and efficacy of this surgical technique that is relatively amenable to nearly all new in-hospital MR suites, we sought to adapt this approach at our sister hospital where a new short-bore 3-T MR suite was being installed. Using many of the lessons learned from our initial experience at 1.5-T, we designed a new interventional suite that would enable surgery to be performed entirely within a 3-T MR environment. All surgical instrumentation including electrocautery, fiberoptic headlamp, power drill, and ultrasonic aspirator was entirely MR-compatible. A few items with limited ferromagnetism were utilized within the magnetic field under strict precaution. From 2/04 to 7/05, those cases initially performed within the 3-T surgical suite included one drainage and reservoir placement for a cystic craniopharyngioma, five brain biopsies and two craniotomies; one for open brain biopsy and another for lesion resection. The craniopharyngioma was successfully aspirated and had the reservoir catheter placed within the cyst. All five brain biopsies yielded diagnostic tissue. The craniotomy for mass resection demonstrated radiation necrosis. Although the metallic artifact from the biopsy needle was more prominent than at 1.5-T, accurate image interpretation was possible. Surgical needles, disposable scalpel, disposable razor, and surgical stapler were minimally ferromagnetic and safely controlled by the surgeon. There were no adverse events associated with any␣procedure. MR-guided neurosurgery can be safely and effectively performed at 3-T. The surgical environment at 3-T is comparable to that present at 1.5-T.

Halo immobilization and surgical fusion: relative indications and effectiveness in the treatment of 140 cervical spine injuries.

In the management of cervical spine injuries, it is not always clear when to use halo immobilization alone, surgical fusion alone, or a combination of the two. To investigate the relative effectiveness of each of these approaches, we reviewed the medical records of 140 patients with cervical spine injuries treated with either halo immobilization or surgical fusion, or both. Seventy (50%) of the patients were neurologically intact on admission (two of these were paraplegic from previous injuries). Halo immobilization was used as the primary treatment in 99 patients, and yielded a successful fusion rate of 78%. Within this group, the 26 patients with hyperflexion-anterior subluxation injuries had only a 54% successful fusion rate, while the rate for the 73 with non-flexion injuries was 87% (Chi-square = 11.36; p = 0.0008). Surgical fusion was used as the primary treatment in 41 patients and as a subsequent treatment in the 22 for whom halo immobilization did not bring about fusion. Of these 63 patients treated with surgical fusion, six remained unstable after the surgery; five of these six had sustained a hyperflexion-anterior subluxation. One patient experienced neurologic deterioration after surgical fusion. There were three deaths in the entire series. Excluding fusion failure, complications with halo immobilization were frequent (25%) but usually minor; with surgical fusion, less frequent (6%) but usually more severe. We draw the following conclusions. 1) Halo immobilization brings about satisfactory healing for most fracture types. 2) Both halo immobilization and surgical fusion have relatively high failure rates in the treatment of hyperflexion-anterior subluxation injury, with or without bilaterally locked facets.(ABSTRACT TRUNCATED AT 250 WORDS)

The Initial Use of Free-running Electromyography to Detect Early Motor Tract Injury during Resection of Intramedullary Spinal Cord Lesions

OBJECTIVE: The resection of intramedullary spinal cord lesions (ISCLs) can be complicated by neurological deficits. Neuromonitoring has been used to reduce intraoperative risk. We have used somatosensory evoked potentials (SEPs) and muscle-derived transcranial electrical motor evoked potentials (myogenic TCE-MEPs) to monitor ISCL removal. We report our retrospective experience with the addition of free-running electromyography (EMG). METHODS: Thirteen patients underwent 14 monitored ISCL excisions. Anesthesia was maintained with minimal inhalant to reduce motoneuron suppression and enhance the myogenic TCE-MEPs. Free-running EMG was examined in the four limbs for evidence of abnormal bursts, prolonged tonic discharge, or sudden electrical silence. Warning of an electromyographic abnormality or myogenic TCE-MEP loss prompted interventions, including blood pressure elevation, a pause in surgery, a wake-up test, or termination of surgery. Pre- and postoperative neurological examinations determined the incidence of new deficits. RESULTS: The combined use of free-running EMG and myogenic TCE-MEPs detected all eight patients with a new motor deficit after surgery; there was one false-positive report. In three of the eight true-positive cases, an electromyographic abnormality immediately anticipated loss of the myogenic TCE-MEPs. Two patients with abnormal EMGs but unchanged myogenic TCE-MEPs experienced mild postoperative worsening of motor deficits; myogenic TCE-MEPs alone would have generated false-negative reports in these cases. CONCLUSION: During resection of ISCLs, free-running EMG can supplement motor tract monitoring by TCE-MEPs. Segmental and suprasegmental elicitation of neurotonic discharges can be observed in four-limb EMG. Abnormal electromyographic bursts, tonic discharge, or abrupt electromyographic silence may anticipate myogenic TCE-MEP loss and predict a postoperative motor deficit.

Acute cervical myelopathy from hereditary multiple exostoses: case report

A case of hereditary multiple exostoses with acute cervical myelopathy, tetraplegia, and apnea is reported. Neurological complications as a result of osteochondromas in hereditary multiple exostoses are rare. The majority of osteochondromas in the cervical spine arise from the neural arch. Magnetic resonance imaging and computed tomography are invaluable in localizing the origin of the lesion and its relationship to the spinal cord. Decompressive laminectomy usually results in excellent functional recovery. Where significant dorsal spinal cord compression exists without neurological deficit, prophylactic decompression can be recommended.

High prevalence of prior contact sports play and concussion among orthopedic and neurosurgical department chairs

OBJECTIVE Increased understanding of the consequences of traumatic brain injury has heightened concerns about youth participation in contact sports. This study investigated the prevalence of high school and collegiate contact sports play and concussion history among surgical department chairs. METHODS A cross-sectional survey was administered to 107 orthopedic and 74 neurosurgery chairs. Responses were compared to published historical population norms for contact sports (high school 27.74%, collegiate 1.44%), football (high school 10.91%, collegiate 0.76%), and concussion prevalence (12%). One-proportion Z-tests, chi-square tests, and binary logistic regression were used to analyze differences. RESULTS High school contact sports participation was 2.35-fold higher (65.3%, p < 0.001) for orthopedic chairs and 1.73-fold higher (47.9%, p = 0.0018) for neurosurgery chairs than for their high school peers. Collegiate contact sports play was 31.0-fold higher (44.7%, p < 0.001) for orthopedic chairs and 15.1-fold higher (21.7%, p < 0.001) for neurosurgery chairs than for their college peers. Orthopedic chairs had a 4.30-fold higher rate of high school football participation (46.9%, p < 0.001) while neurosurgery chairs reported a 3.05-fold higher rate (33.3%, p < 0.001) than their high school peers. Orthopedic chairs reported a 28.1-fold higher rate of collegiate football participation (21.3%, p < 0.001) and neurosurgery chairs reported an 8.58-fold higher rate (6.5%, p < 0.001) compared to their college peers. The rate at which orthopedic (42.6%, p < 0.001) and neurosurgical (42.4%, p < 0.001) chairs reported having at least 1 concussion in their lifetime was significantly higher than the reported prevalence in the general population. After correction for worst possible ascertainment bias, all results except high school contact sports participation remained significant. CONCLUSIONS The high prevalence of youth contact sports play and concussion among surgical specialty chairs affirms that individuals in careers requiring high motor and cognitive function frequently played contact sports. The association highlights the need to further examine the relationships between contact sports and potential long-term benefits as well as risks of sport-related injury.

Multicentric chordoma: a case report and review of the literature.

BACKGROUND AND IMPORTANCE Chordomas are relatively rare tumors that arise from the neuraxis. Most often, chordomas are single lesions that metastasize late. There have been very few cases of chordomas arising from multiple foci along the neuraxis. Here, we present a case of a multicentric chordoma. CLINICAL PRESENTATION The patient presented with pain in her right neck and soreness in her right shoulder that she had experienced for about 2.5 years that she attributed to a muscle strain. She experienced worsening of her symptoms, which prompted her to seek medical care. The patient underwent an occiput-to-C6 posterolateral fusion with autograft and an occiput-to-C6 posterior segmental instrumentation, along with decompression of the spinal cord. One month after the initial surgery, the patient underwent a second surgery. The C2 and C3 vertebral bodies were completely resected, and a C1-C4 anterior fusion was then carried out. A C5 vertebrectomy and C4-C6 fusion were also performed at this time. The patient then received proton beam radiation to the entire affected area. CONCLUSION Recent studies have suggested that chordomas arise from benign notochordal tumors. We suggest that our patient suffered from multicentric chordomas with possible benign notochordal tumors. Although benign notochordal tumors do not require surgical resection, the possibility of transformation to a malignant lesion requires close follow-up.

Meningeal Hemangiopericytoma with Intracranial Metastases in an HIV-Positive Male: Case Report and Review of the Literature.

Background: Meningeal hemangiopericytoma is a rare, aggressive CNS tumor that tends to invade locally, metastasize, and has a high rate of recurrence. HIV classically increases the risk of 3 AIDS-defining malignancies: Kaposi’s sarcoma, non-Hodgkin’s lymphoma and invasive cervical cancer. More recently, considerable interest has been paid to the link between HIV and a wider range of non-AIDS-defining cancers. An HIV-positive patient with meningeal hemangiopericytoma is described. Case Description: A 36-year-old HIV-positive male presented with worsening headache and ataxia. The patient had experienced similar neurologic symptoms 4 months prior and MRI at that time had showed an extra-axial left cerebellar mass most consistent with benign meningioma. Repeat MRI showed the tumor had increased in size by a factor of greater than 20 in this 4-month period, with 4 small additional foci of similar enhancement. Subtotal resection was performed on the mass and final pathological diagnosis was meningeal hemangiopericytoma. Conclusions: This represents the first reported case of meningeal hemangiopericytoma in an HIV-positive patient. This is also the shortest time to intracranial metastasis ever reported for a meningeal hemangiopericytoma. Although the increased risk in the HIV-positive population of non-AIDS-defining cancers that has been observed in recent years can largely be attributed to cancers with a known viral pathogenesis, it is speculated that HIV infection in this patient may have contributed to the occurrence or unique behavior of this rare tumor.

Traumatic brain injury reduction in athletes by neck strengthening (TRAIN)

Reporting of sports-related concussions (SRCs) has risen dramatically over the last decade, increasing awareness of the need for treatment and prevention of SRCs. To date most prevention studies have focused on equipment and rule changes to sports in order to reduce the risk of injury. However, increased neck strength has been shown to be a predictor of concussion rate. In the TRAIN study, student-athletes will follow a simple neck strengthening program over the course of three years in order to better understand the relationship between neck strength and SRCs. Neck strength of all subjects will be measured at baseline and biannually over the course of the study using a novel protocol. Concussion severity and duration in any subject who incurs an SRC will be evaluated using the Sports Concussion Assessment Tool 5th edition, a questionnaire based tool utilizing several tests that are commonly affected by concussion, and an automated eye tracking algorithm. Neck strength, and improvement of neck strength, will be compared between concussed and non-concussed athletes to determine if neck strength can indeed reduce risk of concussion. Neck strength will also be analyzed taking into account concussion severity and duration to find if a strengthening program can provide a protective factor to athletes. The study population will consist of student-athletes, ages 12–23, from local high schools and colleges. These athletes are involved in a range of both contact and non-contact sports.