Federico C. Vinas

Mitochondrial dysfunction after experimental and human brain injury and its possible reversal with a selective N-type calcium channel antagonist (SNX-111).

We have recently demonstrated in a rat model that traumatic brain injury induces perturbation of cellular calcium homeostasis with an overload of cytosolic calcium and excessive calcium adsorbed on the mitochondrial membrane, consequently the mitochondrial respiratory chain-linked oxidative phosphorylation. was impaired. We report the effect of a selective N-type calcium channel blocker, SNX-111 on mitochondrial dysfunction induced by a controlled cortical impact. Intravenous administration of SNX-111 at varying times post injury was made. The concentration titration profile revealed SNX-111 at 4 mg kg -1 to be optimal, and the time window to be administration at 4 h post-injury, in line with that reported on the effect of SNX-l11 in experimental stroke. Under optimal conditions, SNX-111 significantly improved the mitochondrial respiratory chain-linked functions, such as the electron transfer activities with both succinate and NAO-linked substrates, and the accompanied energy coupling capacities measured ...

Safety and feasibility of craniectomy with duraplasty as the initial surgical intervention for severe traumatic brain injury.

BACKGROUND Decompressive craniectomy has historically served as a salvage procedure to control intracranial pressure after severe traumatic brain injury. We assessed the safety and feasibility of performing craniectomy as the initial surgical intervention. METHODS Of 29 consecutive patients undergoing emergent decompression for severe traumatic brain injury with horizontal midline shift greater than explained by a removable hematoma, 17 had traditional craniotomy with or without brain resection and 12 underwent craniectomy. RESULTS The craniectomy group had lower Glasgow Coma Scale scores at surgery (median, 4 vs. 7; p = 0.04) and more severe radiographic injuries (using specific measures). Mortality, Glasgow Outcome Scale scores, Functional Independence Measures, and length of stay in both the acute care setting and the rehabilitation phase were similar between the surgical groups. CONCLUSION Despite more severe injury severity, patients undergoing initial craniectomy had outcomes similar to those undergoing traditional surgery. A randomized evaluation of the effect of early craniectomy on outcome is warranted.

A Cohort Study of the Safety and Feasibility of Intraventricular Urokinase for Nonaneurysmal Spontaneous Intraventricular Hemorrhage

BACKGROUND AND PURPOSE Small case series have reported potential benefit from thrombolysis after spontaneous intraventricular hemorrhage (IVH). Our objective was to review our experience using intraventricular urokinase (UK) in treating selected patients with IVH. METHODS Using medical records, we identified all patients who received ventriculostomies for CT-confirmed nonaneurysmal nontraumatic spontaneous IVH from December 1992 through November 1996. We reviewed charts and CT images and examined the data for associations with specific outcomes. RESULTS We identified 40 patients, 18 treated with ventriculostomy alone and 22 receiving adjunctive intraventricular UK. The initial Glasgow Coma Scale (GCS) scores of the two groups were similar (P = 0.5). While there was a trend for patients with any intraparenchymal hemorrhage (IPH) to receive UK (P = 0.07), the mean size of IPH in those who received ventriculostomy alone was larger than in those who received adjunctive UK (P = 0.002). There was lower mortality in the group treated with UK (31.8 versus 66.7%; P = 0.03), but there was only a trend toward an increase in favorable outcome (22.2% versus 36.4%; P = 0.3). Overall, the most significant association with outcome was neurological condition at presentation (GCS >5 versus < or = 5; P = 0.003). Receiving UK did not increase the occurrence of complications or hospital length of stay for survivors (P = 0.5). CONCLUSIONS Intraventricular UK remains a safe and potentially beneficial intervention. While it appeared to lower mortality, a randomized, placebo-controlled trial is needed to explore whether the therapy can increase the incidence of favorable outcomes.

Spinal Aspergillus Osteomyelitis

Aspergillus species are uncommon etiologic agents of vertebral osteomyelitis. We describe two patients with lumbar vertebral aspergillosis precipitated by the use of corticosteroids and review 39 cases in the literature. The mean age of the population was 40.04 years. There was male predominance (78% of cases), mainly lumbar involvement (53.7%), and monomicrobial nature of infection; 65.8% of the patients had predisposing factors, while 34.1% had none. Back pain (53.6% of cases) was the predominant symptom, while neurological deficits were present in 29.2% of the patients. White blood cell counts were elevated in 12.2% of the patients, and erythrocyte sedimentation rates were >40 mm/h in 39%. The overall recovery rate was 68.3%, and the mortality rate was 26.8%. Although aspergillus osteomyelitis is primarily treated medically, certain cases may require surgical intervention.

Evaluation of expanded polytetrafluoroethylene (ePTFE) versus polydioxanone (PDS) for the repair of dura mater defects

A comparative animal experimental study was performed to test the potential application of expanded polytetrafluoroethylene (ePTFE) vs. polydioxanone (PDS) as dural substitutes. Sixty male Sprague-Dawley rats underwent a right frontoparietal craniotomy, opening of the dura mater, and a small cortical lesion. The dural defect was covered with a piece of ePTFE or PDS. Animals were sacrificed at 30 days or 90 days. Following decalcification, heads including scalp, skull, and underlying brain were sectioned, stained with hematoxylin-eosin, and histologically analyzed. Dural defects repaired with ePTFE, showed minimal reactive changes and no adhesions to the brain surface. No foreign body type giant cell reaction was seen, and the graft became enclosed in a thin sheet of connective tissue. Dural defects repaired with PDS, showed some giant cell infiltration and ingrowth of collagen fibers. Both substitutes provided satisfactory biological function and biocompatibility. Expanded PTFE advantages included relative suppression of tissue ingrowth, ensheathment by connective tissue, and a high tearing strength. Although both materials show promise for use in dural grafting, further clinical studies are necessary to determine their potential applications as a human dural substitute.

Literature review: sinus pericranii.

Sinus pericranii is a rare circumscribed fluctuating vascular swelling of the scalp that communicates with the intracranial venous system. It has been associated with other intracranial vascular malformations. The tumour is usually round, fluctuant, nonpulsatile, and disappears with compression. Its size increases during manoeuvers that increase the intracranial pressure. Approximately 100 cases were reported in the literature. The antecedents, different surgical procedures, differential diagnoses, and associated malformations were reviewed.

Application Accuracy Study of a Semipermanent Fiducial System for Frameless Stereotaxis

The accuracy of a semipermanent fiducial marker system developed at Wayne State University in collaboration with Fisher-Leibinger (Freiburg, Germany) was compared with reference to a standard stereotactic frame (Zamorano-Dujovny Localizing Unit; Fisher-Leibinger). For each patient in our study, 10 semipermanent markers were placed on the skull through a small incision and a pilot hole drilled for the marker; five markers were used for registration, and five were used for comparison. Gadolinium-enhanced magnetic resonance imaging was performed, and, upon registration using both ring and fiducial markers, 184 random points were collected by infrared digitization. All three-dimensional measurements (x, y, z) were converted into distance values correlating each value to the origin by the formula dij = SQRT (xij2 + yij2 + zij2). The mean difference of fiducial coordinates vs. absolute image coordinates was 1.72 +/- 0.42 mm (P = .0001), implying no significant difference. The mean difference in dij of the stereotactic ring coordinates vs. the absolute image coordinates was 3.35 +/- 0.59 mm (P = .00011). The mean difference in the fiducial markers vs. the stereotactic ring coordinates was 2.95 +/- 0.45 mm (P = .0001). All tests were declared significant at alpha = .016. The combination of interactive guidance with semipermanent fiducial markers allows for accurate localization of intracranial targets (as accurate or even more accurate than the stereotactic frame). Semipermanent fiducial markers facilitate the procedure logistically, allow for staged procedures (i.e., at the skull base or in epilepsy), and provide access for combined supra- and infratentorial approaches. We believe that the semipermanent fiducial markers system might represent an important development leading toward widespread use of interactive image guidance in conventional neurosurgery.

Early hemodynamic changes at the microcirculatory level and effects of mannitol following focal cryogenic injury.

Changes in cerebral blood flow due to infusion of hyperosmolar solutions are of considerable importance in states of raised intracranial pressure. The present study was aimed to evaluate the effects of mannitol on the cerebral microcirculation, in a model of vasogenic brain edema. A right fronto-parietal craniotomy was performed in 30 adult Sprague-Dawley rats. Vasogenic edema was produced by placing dry-ice over the dura for 1 min. The cortical blood flow was monitored for 120 min using a laser-Doppler flowmeter (Perimed, Stockholm, Sweden), and graphics were recorded using a personal computer. Animals were randomly divided into three groups: group 1 (control group) received no mannitol; group 2 was treated with a bolus injection of 20% mannitol (1 mg kg-1); group 3 received the same dose over a 30 min infusion. Mean blood pressure, temperature, and respiratory rate were continuously monitored. At the end of the procedure, an intravenous injection of Evans blue 2% was given. Results were compared by using repeated measures of analysis of variance and a two-sample t-test at each time. After the production of a cryogenic injury, we found a marked decrease in the cerebral blood flow, whereas mannitol partially reversed that effect. There was not significant difference between groups 2 and 3; however, there was a significant difference between mannitol and control groups after 15 min. During the early phase of vasogenic edema, early use of mannitol did not increase the blood flow, but stabilized it, preventing further decrease. Laser-Doppler flowmetry is a valuable method for continuous estimation of hemodynamic changes in the cerebral microcirculation.

Microsurgical anatomy of the suboccipital segment of the vertebral artery

The craniocervical regions of seven cadavers (14 sides) injected with silicone rubber were dissected under a Zeiss OPMI surgical microscope. The present study provides a detailed description of the suboccipital segment of the vertebral artery, with particular attention to its loops, branches, supporting osteofibrous structures, adjacent nerves, and surrounding venous structures. Several ligaments fixating the vertebral artery to surrounding structures, which have not been described in previous anatomical studies, were found. The authors propose an anatomically based subdivision of the suboccipital segment of the vertebral artery into five subsegments: infraforaminal, foraminal, supraforaminal, horizontal, and intramembranous. Measurements of surgically and clinically important features were obtained. Surgical approaches to this region are suggested based on a more informed understanding of the local anatomy.

Spontaneous resolution of a syrinx

Syrinx are often related to trauma, tumours or abnormalities of the craniocervical junction. Only a few cases of spontaneous resolution have been reported in the literature. The authors present a case of spontaneous resolution of a cervical syrinx, and analyse the possible physiopathological mechanisms leading to resolution. Other similar cases reported in the literature were collected and analysed.