Microstructure and Mechanical Properties of PU/PLDL Sponges Intended for Grafting Injured Spinal Cord.

Highly porous, elastic, and degradable polyurethane and polyurethane/polylactide (PU/PLDL) sponges, in various shapes and sizes, with open interconnected pores, and porosity up to 90% have been manufactured. They have been intended for gap filling in the injured spinal cord. The porosity of the sponges depended on the content of polylactide, i.e., it decreased with the increase of polylactide content. The rise of polylactide content caused an increase of Young modulus and rigidity as well as a more complex morphology of the polyurethane/polylactide blends. The mechanical properties, in vitro toxicity, and degradation in artificial cerebrospinal fluid were tested. Sponges underwent continuous degradation with varying degradation rates depending on the polymer composition. In vitro cell studies with fibroblast cultures proved the biocompatibility of the polymers. Based on the obtained results, the designed PU/PLDL sponges appeared to be promising candidates for bridging gaps within injured spinal cord in further in vitro and in vivo studies.

Changes in the level of cardiac troponine and disorders in pulmonary gas exchange as predictors of short- and long-term outcomes of patients with aneurysm subarachnoid haemorrhage.

SUBJECT: Cardiopulmonary abnormalities are common after aneurysmal subarachnoid haemorrhage (aSAH). However, the relationship between short- and long-term outcome is poorly understood. In this paper, we present how cardiac troponine elevations (cTnI) and pulmonary disorders are associated with short- and long-term outcomes assessed by the Glasgow Outcome Scale (GOS) and Extended Glasgow Outcome Scale (GOSE). METHODS: A total of 104 patients diagnosed with aSAH were analysed in the study. The non-parametric U Mann-Whitney test was used to evaluate the difference between good (GOS IV-V, GOSE V-VIII) and poor (GOS I-III, GOSE I-IV) outcomes in relation to cTnI elevation and pulmonary disorders. Outcome was assessed at discharge from the hospital, and then followed up 6 and 12 months later. Pulmonary disorders were determined by the PaO2/FiO2 ratio and radiography. The areas under the ROC curves (AUCs) were used to determine the predictive power of these factors. RESULTS: In the group with good short-term outcomes cTnI elevation on the second day after aSAH was significantly lower (p = .00007) than in patients with poor short-term outcomes. The same trend was observed after 6 months, although there were different results 12 months from the onset (p = .024 and n.s., respectively). A higher peak of cTnI was observed in the group with a pathological X-ray (p = .008) and pathological PaO2/FiO2 ratio (p ≪ .001). cTnI was an accurate predictor of short-term outcomes (AUC = 0.741, p ≪ .001) and the outcome after 6 months (AUC = 0.688, p = .015). CONCLUSION: The results showed that cardiopulmonary abnormalities perform well as predictive factors for short- and long-term outcomes after aSAH.

Unruptured Intracranial Aneurysms: Surgery Still Safe as a Treatment Option.

BACKGROUND: Despite a number of studies on the treatment of unruptured intracranial aneurysms (UIA), the optimal method still remains unclear. OBJECTIVES: The aim of the study was to demonstrate that UIA clipping is a safe procedure and can be a good alternative for patients not qualified for endovascular procedures and who have refused conservative management. MATERIAL AND METHODS: Results were gathered from a sample of 104 patients with UIA treated in our facility over a 9-year period starting January 2005. The data from a medical database was collected, followed by a long-term assessment of the functional outcomes using the modified Rankin Scale (mRS) and of quality of life (QoL) using a SF-36 questionnaire and comparing it to a Polish population reference. RESULTS: Overall postoperative morbidity was 5.7% and the mortality rate was 0%. The mean follow-up period was 6.5 years. A favorable outcome (mRS 0-2) was achieved in all the patients. Ninety-eight patients achieved an mRS score of 0, 2 patients an mRS score of 1, and 4 patients an mRS score of 2. All patients lived at home. Sixty-nine point two percent were fully employed, 27.0% were retired because of age, and only 3.8% relied on government help due to postoperative disability. The QoL index was similar to that of the standard Polish population. CONCLUSIONS: In unruptured cerebral aneurysms, clipping is a safe procedure that provides good outcomes and an unaffected quality of life. It remains a good option especially for patients with MCA aneurysms that are not appropriate for endovascular management.

Lizard tail spinal cord: a new experimental model of spinal cord injury without limb paralysis.

Spinal cord injury (SCI) is a well-known devastating lesion that sadly is very resistant to all treatment attempts. This fact has stimulated the exploration of multiple regenerative strategies that are examined at both the basic and clinical level. For laboratory research, differentin vivomodels are used, but each has many important limitations. The main limitation of these models is the high level of animal suffering related to the inflicted neurologic injury. It has caused a growing tendency to limit the injury, but this, in turn, produces incomplete SCI models and uncertainties in the neuroregeneration interpretation. To overcome such limitations, a new experimental SCI model is proposed. Geckos have been extensively examined as a potential animal model of SCI. Their spinal cord extends into the tail and can be transected without causing the typical neurologic consequences observed in rat models. In this study, we compared the gecko tail SCI model with the rat model of thoracic SCI. Anatomic and histologic analyses showed comparability between the gecko and rat in diameter of spinal canal and spinal cord, as well as applicability of multiple staining techniques (hematoxylin and eosin, immunostaining, and scanning and transmission electron microscopy). We tested the suitability ofin vivostudy with 3 prototype implants for the reconstruction of SCI: a multichannel sponge, a multilaminar tube, and a gel cylinder. These were compared with a spinal cord excision (control). A 20-wk observation revealed no adverse effects of SCI on the animals' well-being. The animals were easily housed and observed. Histologic analysis showed growth of nervous tissue elements on implant surface and implant cellular colonization. The study showed that the gecko SCI model can be used as a primary model for the assessment of SCI treatment methods. It provides a platform for testing multiple solutions with limited animal suffering before performing tests on mammals. Detailed results of the experimental conditions and testing techniques are provided.-Szarek, D., Marycz, K., Lis, A., Zawada, Z., Tabakow, P., Laska, J., Jarmundowicz, W. Lizard tail spinal cord: a new experimental model of spinal cord injury without limb paralysis.

Aneurismal subarachnoid hemorrhage: who remains for surgical treatment in the post-ISAT era?

INTRODUCTION: Although there have been a number of studies on changes and trends in the management of aneurismal subarachnoid hemorrhage (aSAH) since publication of the International Subarachnoid Aneurysm Trial (ISAT), no data exist on what category of patients still remains for surgical treatment. Our goal was to investigate the changes that occurred in the characteristics of a population of aSAH patients treated surgically in the post-ISAT period in a single neurosurgical center, with limited availability of endovascular service. MATERIAL AND METHODS: The study included 402 aSAH patients treated surgically in our unit between January 2004 and December 2011. Each year, data regarding number of admissions, age, aneurysm location and size, clinical and radiological presentation, outcome and mortality rates were collected and analyzed. RESULTS: The annual number of admissions more than halved in the study period (from 69 in 2004 to 32 in 2011). There were no linear trends regarding patients' mean age, clinical presentation and outcomes, but the number of patients in Fisher grade 4 increased and mortality slightly decreased. An unexpected, statistically significant increase occurred in the incidence of anterior communicating artery aneurysms (from 36.2% to 50%) and medium size aneurysms (from 34.7% to 56.2%) treated surgically, with a corresponding decrease in the incidence of middle cerebral artery aneurysms (from 40.5% to 34.3%) and large aneurysms (from 21.7% to 12.5%). CONCLUSIONS: Unexpected trends in characteristics of aSAH patients treated surgically could be related to treatment decision modality. Trend patterns could be properly expressed in the constant availability of endovascular services.

Obtaining the olfactory bulb as a source of olfactory ensheathing cells with the use of minimally invasive neuroendoscopy-assisted supraorbital keyhole approach--cadaveric feasibility study.

BACKGROUND: Obtaining the human olfactory bulb (OB) for treatment of spinal cord injuries with olfactory ensheathing cells (OECs) requires the elaboration of a surgical approach that could meet the criteria of safety and minimal invasiveness. The aim of the study was to evaluate the suitability of the keyhole supraorbital craniotomy (SOC) with an eyebrow incision for obtaining OB for therapeutic purposes. METHODS: Seventeen SOCs were performed on nine fresh adult cadavers. The procedure of obtaining OB was conducted by neuroendoscope-assisted microsurgical dissection. Technical features related to the procedure were measured and adverse events were noted. The virtual three-dimensional planning was applied in six cases to verify the authorial A-C scale published previously. RESULTS: The intact OB was obtained in 10 (59%) cases and a minor injury was discovered in another 5 (29%) cases. In 2 (12%) specimens OB was severely damaged which was correlated with the minor neural tissue injury (Fi(2) = 0.44). While no case of an evident vascular injury was noted, there were 3 (18%) incidents of unintended frontal sinus opening positively correlated with the craniotomy width (Fi(2) = 0.44). The unfavorable three-dimensional (3D) configuration of the olfactory groove area was revealed in 66% of cases and highly correlated with OB injury (Fi(2) = 1.0) but not damage. CONCLUSIONS: The SOC via an eyebrow incision may be safely and effectively applied to obtain the OB as a source of OECs in roughly 90% of cases. Virtual 3D planning is useful in preoperative qualification of potential donors.

Functional regeneration of supraspinal connections in a patient with transected spinal cord following transplantation of bulbar olfactory ensheathing cells with peripheral nerve bridging.

Treatment of patients sustaining a complete spinal cord injury remains an unsolved clinical problem because of the lack of spontaneous regeneration of injured central axons. A 38-year-old man sustained traumatic transection of the thoracic spinal cord at upper vertebral level Th9. At 21 months after injury, the patient presented symptoms of a clinically complete spinal cord injury (American Spinal Injury Association class A-ASIA A). One of the patient's olfactory bulbs was removed and used to derive a culture containing olfactory ensheathing cells and olfactory nerve fibroblasts. Following resection of the glial scar, the cultured cells were transplanted into the spinal cord stumps above and below the injury and the 8-mm gap bridged by four strips of autologous sural nerve. The patient underwent an intense pre- and postoperative neurorehabilitation program. No adverse effects were seen at 19 months postoperatively, and unexpectedly, the removal of the olfactory bulb did not lead to persistent unilateral anosmia. The patient improved from ASIA A to ASIA C. There was improved trunk stability, partial recovery of the voluntary movements of the lower extremities, and an increase of the muscle mass in the left thigh, as well as partial recovery of superficial and deep sensation. There was also some indication of improved visceral sensation and improved vascular autoregulation in the left lower limb. The pattern of recovery suggests functional regeneration of both efferent and afferent long-distance fibers. Imaging confirmed that the grafts had bridged the left side of the spinal cord, where the majority of the nerve grafts were implanted, and neurophysiological examinations confirmed the restitution of the integrity of the corticospinal tracts and the voluntary character of recorded muscle contractions. To our knowledge, this is the first clinical indication of the beneficial effects of transplanted autologous bulbar cells.

Biomechanical characteristics of the porcine denticulate ligament in different vertebral levels of the cervical spine-preliminary results of an experimental study.

BACKGROUND: Few studies exist on the mechanical properties of denticulate ligaments and none report the variation in these properties at different levels of the spine. The aim of this study was to perform an experimental determination of load-extension and stress-strain characteristics of the denticulate ligament and to establish if their properties change at different vertebral levels of the cervical spine. METHOD: The study was carried out on a total of 98 porcine denticulate ligament samples dissected from seven fresh porcine cervical spinal cord specimens. All of the samples were subjected to an uniaxial tensile test at a speed of 2mm/min, during which the load-extension characteristics were registered. RESULTS: The analysis revealed a decrease of the failure force in the caudal orientation indicated by significant differences between the C1 (1.04±0.41N) and C7 (0.55±0.12N) vertebral levels (P=0.037). The average ultimate force that broke the denticulate ligaments was 0.88N. The mean value of Young׳s modulus was 2.06MPa with a minimum of 1.31MPa for C7 and maximum of 2.46MPa for C5. CONCLUSIONS: The values of the denticulate ligament failure force in samples from different cervical vertebrae levels differ significantly. The presented data should be taken into consideration during numerical modelling of the human cervical spinal cord.

The supraorbital keyhole approach via an eyebrow incision applied to obtain the olfactory bulb as a source of olfactory ensheathing cells--radiological feasibility study.

BACKGROUND. The purpose of the study was to test the suitability of supraorbital keyhole craniotomy with an eyebrow incision for obtaining olfactory bulb for therapeutic purposes. METHODS. Fifty three high-resolution axial head computed tomography images of patients with a mean age of 55 ± 15 years were used. The exclusion criterion was a pathology of the anterior skull base. The virtual keyhole supraorbital craniotomy was placed on each side of a three-dimensional skull model with respect to the anatomical landmarks. Trajectories of neurosurgical instrument transitions to the anterior and posterior aspects of olfactory grooves (OGs) were subsequently designed with the use of a neuronavigation planning station and measured with correction allowing the avoidance of collisions with skull base structures. Three types of anatomical configuration were divided, reflecting the extent of the correction needed to reach the bottom of OG. RESULTS. Simulation of the surgical access and consequent metrological analysis was performed on 97 skull sides - 9 (8.5%) sides were excluded due to the large frontal sinus. The mean length of the craniotomy basis was 30.71 mm, lengths of the anterior and posterior trajectories were 53.25 and 58.24 mm, respectively (p < 0.0001). In 37% of cases the value of the corrections exceeded the depth of OG. CONCLUSIONS. The supraorbital keyhole approach via an eyebrow incision may be applied to obtain the olfactory bulb as a source of olfactory ensheathing cells in over 60% of cases. Further verification and evaluation of the surgical handiness based on cadaver specimens is justifiable.

Recovery and quality of life in patients with ruptured cerebral aneurysms.

PURPOSE: Subarachnoid hemorrhage (SAH) secondary to ruptured cerebral aneurysm is a common and frequently devastating condition with a high mortality and morbidity among survivors. The purpose of this study was to conduct a long-term follow-up of SAH patients, assess the changes in functional outcomes, describe quality of life (QOL), and determine its predictors 3.6 years after the hemorrhage. DESIGN: The study design is an exploratory, descriptive correlational design. METHODS: Results were collected from a sample of 113 SAH survivors treated in our institution over a 2-year period (January 2006 until December 2007). We collected data on early and long-term functional outcomes and compared the differences. The health-related QOL was measured using the Polish version of The Short Form - 36 Health Survey Questionnaire (SF-36v2). Multivariable logistic regression was derived to define independent predictors of the QOL. FINDINGS: The mean follow-up time was 3.6 years. Sixty-six percent of patients had improvement in functional outcomes and among previously employed people 56% returned to work. QOL deteriorated in 24% of patients with the most affected dimension of Physical Role. Factors that predict good QOL are male gender, younger age, good economic/professional status, lack of physical handicaps, rehabilitation in a professional center, subjective improvement in health status, and absence of headaches or physical decline. CONCLUSIONS AND CLINICAL RELEVANCE: Recovery process in SAH patients is dynamic and progresses over time. Since physical handicaps and low economic status significantly reduce the quality of life, an effort should be made to provide intensive rehabilitation and to encourage SAH survivors to return to work.

Transplantation of autologous olfactory ensheathing cells in complete human spinal cord injury.

Numerous studies in animals have shown the unique property of olfactory ensheathing cells to stimulate regeneration of lesioned axons in the spinal cord. In a Phase I clinical trial, we assessed the safety and feasibility of transplantation of autologous mucosal olfactory ensheathing cells and olfactory nerve fibroblasts in patients with complete spinal cord injury. Six patients with chronic thoracic paraplegia (American Spinal Injury Association class A-ASIA A) were enrolled for the study. Three patients were operated, and three served as a control group. The trial protocol consisted of pre- and postoperative neurorehabilitation, olfactory mucosal biopsy, culture of olfactory ensheathing cells, and intraspinal cell grafting. Patient's clinical state was evaluated by clinical, neurophysiological, and radiological tests. There were no adverse findings related to olfactory mucosa biopsy or transplantation of olfactory ensheathing cells at 1 year after surgery. There was no evidence of neurological deterioration, neuropathic pain, neuroinfection, or tumorigenesis. In one cell-grafted patient, an asymptomatic syringomyelia was observed. Neurological improvement was observed only in transplant recipients. The first two operated patients improved from ASIA A to ASIA C and ASIA B. Diffusion tensor imaging showed restitution of continuity of some white matter tracts throughout the focus of spinal cord injury in these patients. The third operated patient, although remaining ASIA A, showed improved motor and sensory function of the first spinal cords segments below the level of injury. Neurophysiological examinations showed improvement in spinal cord transmission and activity of lower extremity muscles in surgically treated patients but not in patients receiving only neurorehabilitation. Observations at 1 year indicate that the obtaining, culture, and intraspinal transplantation of autologous olfactory ensheathing cells were safe and feasible. The significance of the neurological improvement in the transplant recipients and the extent to which the cell transplants contributed to it will require larger numbers of patients.

Morphological characterization of gecko's (eublepharis macularius) glial cells in culture / Caracterización morfológica de las células gliales del gecko (eublepharis macularius) en cultivo

Central nervous system of reptiles has the ability to grow and regenerate during adult life of the animal. Therefore, cells creating CNS of this animal class should compound substances or molecules enabling neuroregeneration. Cells directly involved in this process have not been clearly characterized, especially in cell culture environment. Morphology of reptilian glial adherent cells should be known better to find any differences from mammalian CNS cells. We isolated glial cells from olfactory bulb and cerebrum from gecko (Eublepharis macularius) and cultured separately. We have observed populations of cells with proliferative capacity in both types of cultures. Also, we have detected lipid molecules deposits within their cytoplasm, which localization was correlated with mitochondria position. This information can be helpful in searching new bioactive substances involved in regeneration of central nervous system.

El sistema nervioso central de los reptiles tiene la capacidad de crecer y regenerarse durante la vida adulta del animal. Por lo tanto, las células de SNC creadas de esta clase de animales deberían componerse de sustancias o moléculas que permiten la neuroregeneración. Las células que participan directamente en este proceso no han sido claramente caracterizadas, especialmente en el entorno de cultivo celular. La morfología de las células adherentes gliales de reptiles deben ser reconocidas y diferenciarse respecto a las células del SNC de mamíferos. Se aislaron células gliales del bulbo olfatorio y el cerebro del Gecko (Eublepharis macularius) y se cultivaron por separado. Se observaron poblaciones de células con capacidad proliferativa en ambos tipos de cultivos. Además, se detectaron moléculas de depósitos lipídicos dentro de su citoplasma, y su localización se correlacionó con la posición de las mitocondrias. Esta información puede ser útil en la búsqueda de nuevas sustancias bioactivas que participan en la regeneración del sistema nervioso central.

Surgical management in patients with aneurysmal subarachnoid hemorrhage. The outcomes in the paradigm shift period.

BACKGROUND: The treatment of cerebral aneurysms has undergone significant evolution since the 1990s when the endovascular methods were introduced. After the results of ISAT were published in 2002, a change in practice occurred which resulted in more ruptured aneurysms treated endovascularly rather than by surgical clipping. This change in practice was referred to as a paradigm shift. OBJECTIVES: The aim of this study was to review the treatment outcomes in patients with ruptured anterior cerebral aneurysms and to delineate the trends in surgical management in the age of the formation of centers for interventional neuroradiology. MATERIAL AND METHODS: The number of patients with subarachnoid hemorrhage treated by surgical means annually between 2004 and 2010 was identified. The patients' data and aneurysm characteristics were collected from the clinical database. The primary outcome measure was the GOS on discharge. Multivariable logistic regression was derived to define independent predictors of the outcomes. RESULTS: The study enrolled 361 SAH patients in which the total number of 409 aneurysm was clipped. Most of the aneurysms (75.7%) were equal to or less than 10mm. In late 2006, after the new center for interventional neuroradiology was established in WMU, the number of aneurysmal SAH patients treated surgically decreased significantly and has remained at that level for subsequent years. Favorable outcomes were achieved in 62.8% of the patients, unfavorable outcomes in 37.1%, including 77 deaths (21.3%). In multivariable analysis, unfavorable outcome was associated with increasing age, worsening neurological grade assessed by the Glasgow Coma Scale (GCS), hemiparesis or aphasia on admission, high Fisher grade, intracerebral hematoma, chronic comorbidities and delayed vasospasm. CONCLUSIONS: The introduction of endovascular methods in the treatment of patients with aneurismal SAH resulted in an almost halving of the number of patients treated surgically. The outcomes of patients with cerebral aneurysms depend mainly on non-modifiable factors (the neurological state of the patients on admission and age). GCS has a better predictive value for outcomes in patients with aneurysmal SAH than the commonly-used WFNS and Hunt-Hess scales. Due to the fact that the majority of aneurysms are small or medium sized, the authors recommend the treatment of unruptured aneurysms less than 10 millimeters as a prevention of SAH.

Influence of calcium alginate on peripheral nerve regeneration: in vivo study.

Recently, we described the influence of sodium alginate on the inflammatory infiltrate during neuroregeneration in tube nerve grafts. It was noticeable that there was the coexistence of inflammatory cells, including neutrophils, plasma cells, and macrophages with Schwann cells and axons. This may indicate a beneficial interaction between alginates and the infiltrate and the additional beneficial effect of the cells on the neuroregeneration process in the inflammatory infiltrates. In this study, we have performed in vivo evaluation of our novel tubular implant prepared by a polyurethane/polylactide blend filled with alginate fibers. The influence of filling the lumen of the tubes with sodium and calcium alginates on the regeneration process of the rat sciatic nerve was investigated. The neuroregeneration process was assessed by detailed histomorphometric studies, axon counting, and calculating the regenerative indexes. It was observed that calcium alginate had a supportive effect on nerve regeneration similar to nerve autotransplant.

Usefulness of intraoperative magnetic resonance ventriculography during endoscopic third ventriculostomy.

BACKGROUND: Endoscopic third ventriculostomy (ETV) is the preferred method for the treatment of noncommunicating hydrocephalus. The different success rates of ETV indicate the difficulties in predicting the success of this procedure. OBJECTIVE: To show the usefulness of intraoperative ventriculography performed by the low-field 0.15-T magnetic resonance imager Polestar N20 during ETV. METHODS: The study was conducted in 11 patients with noncommunicating hydrocephalus caused by tumors or cysts of the third ventricle (n = 5), nontumoral stenosis of the sylvian aqueduct (n = 3), and fourth ventricle outlet obstruction (n = 3). Intraoperative magnetic resonance (iMR) ventriculography was performed before and after the ETV. RESULTS: In each case, iMR-ventriculography was a safe procedure and determined the exact site of obstruction of cerebrospinal fluid flow. In all cases, iMR-ventriculography performed after ETV showed with the greatest accuracy the patency of the performed fenestrations, demonstrating in 9 patients good flow of the contrast from the third ventricle to the basal cisterns, restricted flow in 1 patient, and no flow in 1 patient. The results of ventriculography were consistent with the postoperative neurological status of operated-on patients. In 3 patients, the opinion of the surgeons about the patency of endoscopic fenestration, based on intraoperative observation of the third ventricle floor, was inconsistent with the results from iMR-ventriculography. CONCLUSION: Low-field iMR-ventriculography is a safe procedure that can be successfully applied during ETV to determine the site of obstruction in hydrocephalus and the patency of performed ventricle fenestration.

Usefulness of perfusion weighted magnetic resonance imaging with signal-intensity curves analysis in the differential diagnosis of sellar and parasellar tumors: preliminary report.

PURPOSE: The most common pituitary tumors are adenomas, which however may be mimicked by other tumors that can show a very similar appearance in plain MRI. The aim of our study was to evaluate the usefulness of perfusion weighted MR imaging (PWI), including signal-intensity curves analysis in the differential diagnosis of sellar/parasellar tumors. METHODS: Forty-one patients with sellar/parasellar tumors (23 macroadenomas, 10 meningiomas, 5 craniopharyngiomas, 1 intrasellar hemangioblastoma, 1 intrasellar prostate cancer metastasis, 1 suprasellar glioma), underwent plain MRI followed by PWI using a 1.5T unit. In each tumor, the mean and maximum values of relative cerebral blood volume (rCBV), as well as the relative peak height (rPH) and the relative percentage of signal intensity recovery (rPSR) were calculated. RESULTS: The high perfusion tumors were: macroadenomas, meningiomas, squamous-papillary type of craniopharyngiomas, hemangioblastoma, glioma and metastasis. The low perfusion neoplasms included adamantinomatous type of craniopharyngiomas. By comparing adenomas and meningiomas, we found statistically significant differences in the mean and maximum rCBV values (p=0.026 and p=0.019, respectively), but not in rPH and rPSR. The maximum rCBV values >7.14 and the mean rCBV values >5.74 with the typical perfusion curve were very suggestive of the diagnosis of meningioma. There were differences between adenomas and other high perfusion tumors in rPH and rPSR values. CONCLUSIONS: PWI can provide additional information helpful in differential diagnosis of sellar/parasellar tumors. In our opinion PWI, as an easy to perform and fast technique should be incorporated into the MR protocol of all intracranial neoplasms including sellar/parasellar tumors.

Assessment of in vivo behavior of polymer tube nerve grafts simultaneously with the peripheral nerve regeneration process using scanning electron microscopy technique.

In this study, scanning electron microscopy (SEM) has been applied for instantaneous assessment of processes occurring at the site of regenerating nerve. The technique proved to be especially useful when an artificial implant should have been observed but have not yet been extensively investigated before for assessment of nerve tissue. For in vivo studies, evaluation of implant's morphology and its neuroregenerative properties is of great importance when new prototype is developed. However, the usually applied histological techniques require separate and differently prepared samples, and therefore, the results are never a 100% comparable. In our research, we found SEM as a technique providing detailed data both on an implant behavior and the nerve regeneration process inside the implant. Observations were carried out during 12-week period on rat sciatic nerve injury model reconstructed with nerve autografts and different tube nerve grafts. Samples were analyzed with haematoxylin-eosin (HE), immunocytochemical staining for neurofillament and S-100 protein, SEM, TEM, and the results were compared. SEM studies enabled to obtain characteristic pictures of the regeneration process similarly to TEM and histological studies. Schwann cell transformation and communication as well as axonal outgrowth were identified, newly created and matured axons could be recognized. Concurrent analysis of biomaterial changes in the implant (degradation, collapsing of the tube wall, migration of alginate gel) was possible. This study provides the groundwork for further use of the described technique in the nerve regeneration studies.

Assessment of cerebral blood flow during infusion test in the diagnosis of normal pressure hydrocephalus.

BACKGROUND: Many studies indicate that the increase in intracranial pressure (ICP) leads to cerebral blood flow velocity (CBFV) changes. This relationship was accurately determined in patients with traumatic brain injury, OBJECTIVES: The aim of this study was to determine how the changes in intracranial pressure induced during an infusion test influence cerebral blood flow. MATERIAL AND METHODS: 40 patients with enlarged ventricular systems (Evan's ratio > 30%) who underwent a diagnostic lumbar infusion test (LIT) were included. Tests were performed at the Department of Neurosurgery, Wroclaw Medical University. CBFV in the middle cerebral artery was measured using transcranial Doppler (TCD) simultaneously during the standard lumbar infusion test. TCD measurements were continued with simultaneous recording of CSF pressure with a frequency of 100Hz. A total number of 5800 measurements (10-second periods) performed during the three phases of the infusion test (stable, infusion and decrease) was obtained. RESULTS: In the stable phase of LIT, a weak positive correlation between ICP and mean CBFV (R = 0.193, p < 0.01) was observed. There was no statistically significant correlation between ICP and the pulsatility index (PI, Gosling Index). During the increased-ICP phase of LIT (infusion, decrease), we observed significant changes in CBFV expressed by a decrease of diastolic velocity and an increase of systolic velocity. A simultaneous increase of pulsation correlated with an increase in ICP (R = 0.371, p < 0.01). There were no significant changes in mean CBFV. CONCLUSIONS: In patients with ventriculomegaly, the mean cerebral blood flow is maintained despite a significant increase in ICP, within the limits of the infusion test. It is noted the relative increase of the pulsatility indices of CBF may indicate preserved cerebrovascular reactivity.

Surgical treatment of pituitary adenomas using low-field intraoperative magnetic resonance imaging.

BACKGROUND: Intraoperative magnetic resonance imaging (iMRI) is a new technique for imaging of the brain and is used with increasing frequency during neurosurgical operations, enabling the surgeon to make decisions based on real-time images. OBJECTIVES: This paper presents the technique for the surgical treatment of pituitary adenomas using low-field iMRI, evaluates the safety of iMRI usage in pituitary surgery and examines the influence of iMRI on the extent of tumor removal. MATERIAL AND METHODS: From October 2008 to December 2010, 18 patients were treated for pituitary adenomas using the low-field iMRI system Polestar N20. The procedures were conducted via the transsphenoidal approach, using the microscopic technique in 15 cases and endoscopically in three cases. The patients' mean age was 56 +/- 15 years; their mean American Society of Anesthesiologists (ASA) score was 2; 67% of them were male. Most of the patients were operated on for macroadenomas, 83% of which were hormonally inactive. The analysis concerned the technical aspects of iMRI usage, such as preparation and surgery time and the quality of the iMRI-scans performed. The safety of iMRI and its influence on decisions regarding further tumor resection. RESULTS: The operations on pituitary adenomas using iMRI were safe. Only two hemorrhagic complications were noted, and they were not related to iMRI usage. The mean preparation and surgery times were 109 +/- 37 minutes and 238 +/- 188 minutes, respectively. The iMRI images of sella turcica were of satisfactory quality in 16 patients. In 50% of the cases, iMRI conducted when the surgeon believed that the desired extent of tumor resection had been attained showed that there were still tumor remnants to be resected. In 67% of these cases, continued tumor removal lead to achievement of the desired degree of resection. CONCLUSIONS: Low-field iMRI-guided operations on pituitary tumors are safe and feasible, and they ensure an increased radicality of tumor resection.