A model for intratumoural chemotherapy in the rat brain

To achieve the best reproducibility in rat brain tumour models several injection techniques have been used. Although stereotactic cell injections have proved to be effective and reliable, they are expensive and time consuming. A new permanently implanted device is presented here. It allows precise cell delivery for best tumour reproducibility, and it can be left in place for future injections at the exact same location, such as intratumoural chemotherapy. A Teflon tube was mounted on a disc, inserted into the rat brain and sealed to the skull. The device was tested in two rat strains (Wistar and New Zealand Nude rats) with two different glioma cell lines (9L and C6). Rats were treated with placebo to determine if repeated treatments had an effect on the device placement, or if device-related morbidity was induced. Analysis of brain sections showed that the device path was always within the tumour. The device never moved or came off the scalp. Both Wistar rats and NZ nude rats tolerated the device well. No morbidity or mortality was observed, regardless of the presence of the device; no infections were seen. Biocompatible, non-irritating and well tolerated, such a device can be used for reproducible tumour cell injections and repeated intralesional delivery of drugs.

Fetal allogeneic dopaminergic cell suspension grafts in the ventricular system of the rat: characterization of transplant morphology and graft-host interactions

Experimental transplantation trials of fetal cells in Parkinson's and Huntington's disease or multiple sclerosis still require allogeneic graft material and raise questions of graft rejection and immunosuppression. Alternatively to the striatum, the lateral ventricles have been discussed as grafting site in Parkinson's and Huntington's disease although little is known of the specific immunology of the ventricular system. To address this question, 28 adult female LEW1.W rats received intraventricular allogeneic dopaminergic cell suspension grafts from E14 DA rat fetuses. Twelve animals with syngeneic grafts served as control. Immunohistochemical examination was performed with staining for MHC expression, microglia-macrophages, various lymphocyte subsets, dopaminergic neurons and astrocytes at 4 days, and 1, 3, 6, and 12 weeks after transplantation. In all animals, intraventricular transplants were found, which showed maturation and integration in the host parenchyma at the later time points. Animals with allogeneic grafts developed a vivid immune response with strong MHC class I expression and dense lymphocyte infiltrates. Surprisingly, this immune response subsided at 12 weeks and healthy grafts remained. These results indicate (1) that, in contrast to intraparenchymal grafts, a strong immune response to allogeneic fetal cell suspension grafts can be elicited by intraventricular grafting, (2) that a peculiar immunological role of the ventricular system has to be considered in further studies, and (3) that a vivid immune response to allografts in the brain may subside without graft destruction.

The Ki-67 proliferation antigen in meningiomas. Experience in 600 cases

BACKGROUND

Meningiomas are mostly benign tumours that can be cured by surgical resection. Because meningiomas tend to recur, long term management in patients with subtotal tumour resection remains controversial. Previous studies have shown that the proliferation potential of meningiomas by Ki-67 labelling indices (LI) might predict their natural history. The purpose of this study was to analyse the reliability of Ki-67-labelling index in predicting the behaviour of meningiomas, and to help the neurosurgeon in establishing better follow up criteria and long term management strategies for these patients.

METHOD

From 1990 to 2000 1328 meningiomas have been operated in our Neurosurgical Department. A total of 600 tumours were examined immunohistochemically using the Mib-1 monoclonal antibody. Clinical charts of the patients including surgical, histological and follow up records, as well as imaging studies were analysed retrospectively. Ki-67 LI were correlated with neuroradiological findings, 3D volumetric studies, histological subtype, recurrence-free survival, grade of resection, consistency of tumour tissue, location, osseous involvement, en plaque appearance, vascularity and progesterone-receptor status.

FINDINGS

Among the 600 patients analysed, there were 66% females (mean LI 3.8%) and 34% males (mean LI 5.7%), including 20 neurofibromatosis-type-2 (NF-II) patients with a mean LI of 5.2%. Histological grading revealed 91% WHO degrees I meningiomas (mean LI 3.28%), 7% WHO degrees II (mean LI 9.95%) and 2% WHO degrees III (mean LI 12.18%). Labelling indices in recurrent meningiomas increased from initial resection to a fourth local resection. A significant correlation between negative progesteron-receptor status and high tumour vascularity with high Ki-67 LI was seen. Ki67 was not a statistically significant predictor of survival time in totally excised WHO degrees I meningiomas.

INTERPRETATION

Mib-1 is one important tool in addition to routine histological evaluation, but a combination of clinical factors and particularly the extent of surgical resection, along with the biological features of the tumour, should influence the decision of the neurosurgeon to the patient follow up.

[Congenital teratoma of the skull base: case report of an interdisciplinary treatment]

Teratomas of the oropharynx are quite rare congenital tumors. Even more rare than oropharyngeal teratomas are those with additional intracranial extension. Reviewing the literature the prognosis of these cases has been poor. In the majority stillbirth or immediate postpartum death following respiratory obstruction is reported. We present a case of a congenital teratoma of the oral cavity with intracranial extension in a female neonate. After several intraoral tumor resections to establish secure airway in the postpartum period the total tumor resection had to be performed at the age of 6 month via a lateral transmandibular approach to the skull base. By using extraoral distaction devices the operation related microsomia of the mandible could be corrected at the age of 5 years. At 7 years follow-up the girl presented free of recurrence and without any neurological or functional deficits.

Lateral Transmandibular Approach to the Skull Base in Children: Three Case Reports

The choice of surgical approach to tumors of the cranial base in children is determined by strict criteria. The criteria include optimal visibility for the surgeon, minimal possible impairment of facial skull growth, and the preservation of motor and sensory nerve integrity. From 1993 to 1996, three children (6 years old, 22 months old, 6 months old, respectively) underwent surgery to resect cranial base tumors through a modified lateral transmandibular approach. In all three patients a preauricular incision with temporal and submandibular extensions was performed. After the mandible was prepared, an osteotomy was conducted cranially to the mandibular foramen. When the capitulum was temporarily disarticulated, wide access to the cranial base was provided and the tumors were resected. Two of these children were available for follow-up, and we continue to observe their development. Given the severity of their conditions, treatment yielded good results. Growth impairment of the mandible was corrected by the distraction osteogenesis technique.

Surgical management of a meningioma in the retrosellar region

Lesions ventral to the brainstem in the retrosellar and interpeduncular region are major challenges to the surgeon because of their location at great depth in the centre of the cranial base. We report the operative management of a patient with a meningioma in an unusual location, extending from the upper clivus, retrosellar and interpeduncular region into the suprasellar area up to the level of the foramen of Monro. A 41-year-old man presented with a 3-month history of progressive visual disturbance, episodic headache and signs and symptoms of endocrinological disturbance. Magnetic resonance imaging (MRI) studies showed a homogeneously enhancing tumour ventral to the brainstem with large cranio-caudal extension from the upper clivus to the suprasellar area. Operative removal was planned in two stages. First, through a right lateral suboccipital retrosigmoid craniectomy the caudal portion of the tumour at the upper clivus and prepontine region was removed. Second, the residual suprasellar part of the tumour was removed totally through a fronto-lateral craniotomy on the right side one week later. When a tumour is very large or involves different areas of the skull base, it is necessary to decide between removal in one stage, which requires a complex and time consuming skull base approach, or in multiple stages. Our case demonstrates how a retrosellar meningioma extending to the suprasellar region can be totally removed using two simple skull base approaches without the risk of compromise to venous drainage and without the need for extensive bone removal as described in other skull base approaches.

Temporal and regional profile of neuronal and glial cellular injury after induction of kaolin hydrocephalus

AIM

To study regional and temporal pattern of glial and neuronal reaction to induction of kaolin hydrocephalus in adult rats. Enzyme- and immunohistochemistry was performed in 20 adult rats with kaolin-hydrocephalus after 2, 4, 6 and 8 weeks to glial glutamatergic transmission activity (GLDH) and neuronal nitrous oxide synthetic activity (nNOS). Also, glial fibrillary acidic protein (GFAP), 68 kd neurofilament protein (NF68) and synaptophysin (SYN38) and basic fibroblastic growth-factor (bFGF) were stained. Results were quantified by imaging analysis (SCION IMAGE) and expressed as relative immunopositive area. After 2 weeks, nNos-activity increased in cortical and hippocampal neurones (CA1 and CA3) and GLDH-activity also showed increases, most significant in periventricular white matter (25.7 +/- 3.8 vs. 15.5 +/- 4.9; p < 0.001) and hippocampus (p < 0.01). After 4 or 6 weeks, global cortical GLDH-activity showed further marked increases (25.7 +/- 3.9 vs. 11.3 +/- 1.5; p < 0.05), while sustained structural changes have occurred: GFAP decreased in periventricular (3.3 +/- 0.5 vs. 6.3 +/- 1.2; p < 0.01), hippocampal and cortical astrocytes (0.9 +/- 0.34 vs. 5.0 +/- 0.7%; p < 0.01), whereas NF68 in cortical efferent neurones increased (6.5 +/- 1.5% vs. 4.7 +/- 0.1; p < 0.01) followed by a decrease in cortical and hippocampal (CA1) SYN 38 (p < 0.05). Acute glial and neuronal reactions were almost functional and in chronic stages sustained structural changes predominated. Since neuronal reactions were pronounced in selective vulnerable areas glial reaction was not restricted to periventricular astrocytes.

PET-studies in idiopathic chronic hydrocephalus before and after shunt-treatment: the role of risk factors for cerebrovascular disease (CVD) on cerebral hemodynamics

AIM

To investigate the impact of cerebrovascular risk factors in idiopathic chronic hydrocephalus concerning cerebral hemodynamics and clinical outcome after shunting. Global cortical cerebral blood flow (CBF) and cerebrovascular reserve capacity (CVR) in 53 patients (67 +/- 11 yrs) were determined by 15-0-water-PET studies before and after administration of acetazolamide (1 g) prior (pre), one week (7 d) and seven months (7 m) after shunting. According to the prevalence of vascular risk factors (American subcommittee on reporting standards for cerebrovascular disease) patients were classified into a "low-risk" (n = 27) and "high-risk" (n = 20) group; patients with a history of stroke (n = 6) were separated. After 7 months, clinical outcome was assessed according to Stein and Langfitt. While CBF in "high-risk" patients prior to surgery was significantly lower in clinical responder compared to non-responder (32 +/- 5 vs. 42 +/- 15 ml/100 ml/min; p < 0.05), CVR was marginal in both outcome groups (< 30%). One week after shunting, CVR in responder of "high-risk" significantly increased (64 +/- 30 vs. 31 +/- 10% pre; p < 0.01). In "low-risk" patients, differences in CVR prior to shunting were found: CVR was lower in clinical responder than in non-responder (36 +/- 11 vs. 47 +/- 22% pre; p > 0.05) and deteriorated in non-responder (29 +/- 15% vs. 47 +/- 22 pre; p < 0.02) one week after shunting. Different peri-operative characteristics in global CVR regarding clinical response after shunting between both "risk-groups" were observed. Pathophysiological mechanisms upon clinical sequels after shunting in idiopathic hydrocephalus may not be unique.

Long-time in-vivo metabolic monitoring following experimental brain contusion using proton magnetic resonance spectroscopy

In a Sham-controlled study we applied proton magnetic resonance spectroscopy (1H-MRS) at 4.7 T to a model of experimental traumatic brain contusion. The time course of cerebral metabolite changes was monitored in serial investigation in 14 Sprague Dawley rats up to 4 weeks after trauma. 6 animals served as controls. 1H-MRS spectra were acquired from a voxel covering the hippocampus/basal ganglia ipsi and contralateral to the lesion. Metabolites ratios of the injured hemisphere were compared to those ipsilateral in Sham animals and to those of the contralateral side in the trauma animals. NAA/Cr ratio and Glu/Cr ratio, possible markers of neuronal loss, persistently decreased after trauma to a minimum of -40% and -20% versus controls, respectively. One week after trauma Cho/Cr ratio was strongly increased by 73%. This might indicate a high inflammatory activity at that time. Lac/Cr ratio showed long-lasting and continuing increases up to 2000% versus controls as a sign of permanently shifted posttraumatic energy metabolism. 1H-MRS proved to be a useful non-invasive method for in-vivo monitoring of posttraumatic metabolism also in models of brain contusion. In single cases however, accompanying haemorrhage can potentially prevent useful data acquisition.

Dynamic shunt testing applying short lasting pressure waves--inertia of shunt systems

Laboratory shunt testing often comprises only static pressure flow and flow pressure tests. We applied shorter acting pressure waves using a computerised shunt testing rig to investigate shunt behaviour under conditions that might occur in the clinical situation, e.g. during nocturnal vasogenic pressure waves or shorter rises in ICP at movements or exercise. Additionally the influence of a human-like compliance situation compared to a fixed pressure/volume relationship was investigated. Shunts behaved very differently than seen in static tests and demonstrated a marked inertia the shorter pressure waves acted. Although some valves opened at higher pressure, all valves showed marked hysteresis and none did close--if at all--at the specified pressure level. This behaviour might be a cause of shunt overdrainage not related to siphoning. The simulation of a human-like variable pressure-volume relationship with higher compliance at lower pressures had a positive effect on shunt function by decreasing the amount of drained volume. We therefore suggest to include dynamic pressure wave testing if hydrodynamic properties of shunts are to be evaluated.

Traumatic subarachnoidal hemorrhage in the developing rat

The aim of the present study was to utilize an experimental traumatic subarachnoidal hemorrhage model in the developing rat. Diffuse brain injury was produced in intubated and ventilated 21 to 25 days old Sprague-Dawley rats (N = 10) using a modification (1 m/100 g) of the Marmarou-model. Before induction of the injury heparin was administered i.v. and antagonised after injury by protamine. Mean arterial blood pressure and intracranial pressure was measured continuously. Histopathological investigations were performed. The results were compared to readings in adult animals (N = 12) subjected to a 1.5 m/500 g injury. In the developing rat ICP increased immediately following injury from 11.4 +/- 2.1 mm Hg to 55.9 +/- 20.3 mm Hg. It remained elevated till the end of the experiment 1 h after injury. MABP increased from 79.8 +/- 8.7 mm Hg to 100.2 +/- 21.7 mm Hg immediately following injury, returning to 61.3 +/- 28.7 mm Hg at the end of the experiment resulting in a marked decrease of CPP. The mortality rate was 60%. All brains showed a severe subarachnoidal hemorrhage in the basal cisterns. The increase of ICP following injury is attributable to the bleeding similar as in adult animals. The high mortality is due to the marked decrease of CPP. Rat pups are more vulnerable to t-SAH compared to adult rats.

The role of cerebral blood flow and cerebrovascular reserve capacity in the diagnosis of chronic hydrocephalus--a PET-study on 60 patients

AIM

To investigate the clinical value of cerebral blood flow (CBF) and cerebrovascular reserve capacity (CVR) in the management of chronic hydrocephalus. Global cortical CBF and CVR in 60 patients (66 +/- 12 yrs) with chronic hydrocephalus were investigated before, one week (7 d) and 7 months (7 m) after shunting by 15-O-H2O PET (Siemens ECAT 951/31) at rest and after application of acetazolamide (1 g). After 7 months, clinical outcome was assessed according to Stein and Langfitt and patients were classified into responder (n = 31) and non-responder (n = 29). Before Surgery, responder had lower blood flow values compared to non responder (36 +/- 8 vs. 41 +/- 11 ml/100 ml/min; p = 0.04), whereas CVR was not different between outcome groups (33 +/- 10 vs. 41 +/- 8%; p > 0.05). After shunting, CVR in non-responder decreased from 41 +/- 8% to 32 +/- 5% (7 d), whereas in responder significant increases (p < 0.02) to 55 +/- 46% (7 d) and 54 +/- 31% (7 m) were observed. Regarding early individual changes in CVR, the majority (12/18; 66%) of non-responder had marked decreases in CVR-levels (< 30%), whereas clinical responder considerably improved in CVR (> 30%) in half of patients (7/14). Measurement of cerebral blood flow in chronic hydrocephalus might substantially contribute to selection of shunt candidates and neurological sequels may be rather related to early regeneration of the hemodynamic reserve.

Determination of contusion and oedema volume by MRI corresponds to changes of brain water content following controlled cortical impact injury

The time-course of brain contusion/oedema development as visualised by high-resolution MRI was compared to brain water content following experimental brain contusion. 36 Sprague-Dawley rats underwent Controlled Cortical Impact Injury (CCII), 24 served as controls. In 16 animals serial T2 weighted MRI investigations at 1 h, 4 h, 24 h and 7 d after CCII were performed, in 44 rats hemispheric brain water content was determined at the same time points by wet dry weight method. MRI lesion volume (mm3) and brain water content of injured hemisphere (%) showed for absolute and relative values a strictly parallel course. Significant posttraumatic increases had a maximum at 24 hours. Values on day 7 were below those of 1st h in both methods. The simple non-invasive MRI method quantifies contusion and surrounding penumbra according to elevated tissue water signal. The invasive wet dry weight method quantifies changes of hemispheric brain water content that are likely to take place in contusion core and surrounding penumbra. Therefore, from a theoretical aspect both methods seem comparable. Following experimental brain contusion, the simple MRI method might be an equally sufficient way to describe post-traumatic or post-therapeutic changes of lesion size and brain oedema.

Neuropsychological sequels to changes in global cerebral blood flow and cerebrovascular reserve capacity after shunt treatment in chronic hydrocephalus--a quantitative PET-study

AIM

To study relationship of neuropsychological deficits in chronic hydrocephalus before and after shunting with dynamics in cerebral blood flow. In 27 patients (65 +/- 13 yrs) with idiopathic chronic hydrocephalus 11 selected neuropsychological tests, providing a wide range of psychomotor functions, were performed before, one week (early) and 7 months (late) after shunting. Parallel global cortical blood flow (CBF) and cerebrovascular reserve capacity (CVR) were determined by dynamic 15-O-water PET studies (Siemens ECAT 951/31) before and after application of acetazolamide (1 g). Test raw data and changes after treatment were compared with global and regional blood flow values by polynomial regression. No relationship of test profiles with hemodynamics before surgery was found. After one week, improvement of gait was related to an increase in cerebrovascular reserve capacity (p = 0.05). After 7 months changes in mental tests were related to changes in hemodynamics: again increases in CVR were significantly related to improvements in visual attention and verbal memory (p < 0.01). Early improvement of hemodynamic reserve was related to improvement in gait, whereas mental improvement was particularly related to increases in global CVR at later periods after shunting. These results indicate that neurological sequels in idiopathic chronic hydrocephalus after shunting may actually depend on consecutive improvement of cerebral hemodynamics.

Regional cerebral blood flow profiles of shunt-responder in idiopathic chronic hydrocephalus--a 15-O-water PET-study

AIM

To find out if regional characteristics of cerebral blood flow (CBF) and cerebrovascular reserve capacity (CVR) may indicate shunt response in idiopathic chronic hydrocephalus. 11 patients with idiopathic chronic hydrocephalus (65 +/- 13 yrs) were followed-up within a year after shunting. Patients were classified into clinical responder (n = 5) and non-responder (n = 6) according to Stein and Langfitt. All patients had measurement of CBF and CVR with dynamic 15-O-water PET (Siemens ECAT 951/31) before and after application of acetazolamide (1 g). Regional differences between outcome groups were analysed with "statistical Parametric Mapping" (SPM99b; Wellcome Department, London, UK). Group differences were regarded as significant, when uncorrected p-value on voxel and on cluster level were p < 0.001 and p < 0.05, respectively. Regarding CBF distribution there was significantly reduced CBF in the frontobasal cortex in responder compared to non-responder (cluster level p = 0.026). In CVR, a variety of cortical regions showed significant decreases compared with non-responder: also in frontobasal cortex (on cluster level p = 0.009). However, most significant reductions were found in temporodorsal and limbic cortical regions (on cluster level p < 0.001). Preoperative hemodynamics displayed a regional profile of reduced CBF and CVR in patients with shunt improvement. Prospective studies for determining the accuracy of regional blood flow characteristics for outcome prediction are warranted.

Neuropsychological testing to improve surgical management of patients with chronic hydrocephalus after shunt treatment

AIM

To find out a practical neuropsychological tool for early and reliable outcome assessment in chronic hydrocephalus. In 30 patients (65 +/- 13 yrs.) 11 neuropsychological tests providing a wide range of psychomotor functions (visual and verbal attention, verbal memory and learning and visuomotor skills) were applied before (pre), one week (early) and 7 months (late) after shunting. After 7 months, clinical outcome was classified according to Stein and Langfitt. Statistics included factor analysis, logistic regression and non-parametric tests. Visual attention ("Digit-symbol"), verbal recall ("10-words-list") and motor precision ("line-tracing") were the most representative (and practical) tests (orthogonal loads > 0.9). These tests, in contrast to others, revealed significant differences between outcome groups concerning early postoperative changes: responder showed marked improvement in visual attention t-scores (47 +/- 8 vs. 41 +/- 8 (pre); p = 0.005) and motor precision scores (109 +/- 26 vs. 149 +/- 47 (pre); p = 0.03). Non-responder even decreased in verbal recall t-scores early after shunting (35 +/- 7 vs. 41 +/- 11 (pre); p = 0.007). By logistic regression, visual attention was most sensitive indicating shunt-response by early psychometric changes (p = 0.04). Psychomotor deficits in hydrocephalic patients can be represented by a few neuropsychological skills: visual attention, verbal recall and line tracing. Since they showed early post-operative differences regarding long-term response to shunting they may offer a practical and standardised method for reliable follow-up.

3-D-Segmentierung der Wirbelsäule mit speziell angepaßten Werkzeugen. 3-D Segmentation of the Spine with Specially Adapted Tools

Segmented 3-D data of the spine form the basis for various modern clinical applications. Among these, multisegmental image fusion, image registration and finite element modeling for biomechanical analysis are promising innovative tools capable of facilitating treatment decisions and optimization of individual therapy in the future. However, the complex anatomy of the spine and the often extensive degenerative deformation presenting in clinical practice, generally limit the application of fully automated segmentation. A newly developed software system is presented that meets the complex requirements for image segmentation of the spine through the use of specially adapted interactive tools that take account of its axial skeletal structure. Furthermore, a standardized protocol is introduced that combines the newly developed interactive tools (rotation transformation, warped dissection plane) and standard segmentation tools to permit rapid and accurate segmentation. To date, the software environment presented herein has been applied with success to the segmentation of cervical, thoracic and lumbar spine.

Vestibular schwannomas and auditory function: options in large T3 and T4 tumors?

OBJECTIVE

While hearing preservation has become an accepted treatment goal, there are still major doubts whether and to what extent this aim is feasible in large tumors that cover the auditory nerve and involve the brainstem.

METHODS

One thousand eight hundred (1,800) vestibular schwannomas (VS) were operated on at Nordstadt Neurosurgical Department from 1978 to 1999 by the senior surgeon (MS). There were 1,800 tumors in 1,750 patients, 1,605 patients had unilateral tumors, 145 patients had neurofibromatosis type 2 with bilateral tumors, 195 of which were treated surgically in our unit. Preservation of the cochlear nerve was attempted when ever possible. The audiometric data are analyzed by Hannover Classification System graded in steps of 20 dB by audiometry and in steps of 10% to 30% by speech discrimination. Those data were set into relation with the Hannover tumor extension grading T1 to T4.

RESULTS

Overall preservation rate was 40% with considerable differences, though, depending on the preoperative hearing quality and the tumor extension. Best results were obtained for intrameatal tumors (T1) with 56% and small intra-extrameatal tumors (T2) with 57% preservation rate. While preservation rate was at 44% in medium-sized tumors (T3), it was at 20% for T4 tumors with brainstem compression or even dislocation. However, satisfactory chances were encountered in cases with normal or good preoperative hearing, on average 54%, specifically 71% in T1, 69% in T2, 58% in T3 and 29% in T4. Regarding the quality of the preserved hearing, up to one third of cases in T1 and T2 may retain their preoperative hearing level, while this ranges around 20% for T3 and 10% to 14% in T4 tumors.

DISCUSSION

For long, hearing preservation in medium sized or large tumors has not received any attention because of the presumed lack of realistic chances and the expected bad quality. Obviously, hearing preservation may be achieved in relevant numbers and at satisfactory quality levels. This aspects appears important to be addressed further in view of the fact that over 70% of tumors are presented for surgery at T3 or T4 extensions.

CONCLUSION

The summit of hearing preservation has not been reached as improvements are still achieved even in most difficult conditions.

[Computer assisted plastic closure of calvarial defects]

Large bony skull defects sometimes face problems of some pathophysiological effects, protection of the underlying brain, the impaired appearance, and from a psychological point of view. A computer-assisted method is presented, which has been successfully used in 44 patients. From 3-D-CT data a phantom was built in which Refobacin-Palacos was modeled for individual requirements. The plastic can be implanted after sterilization and leads to excellent cosmetical results. The use of a negative model reveals the possibility of an extended field of application without the necessity of highly specialized computersystems.

Natural history of chondroid skull base lesions--case report and review

Long-term follow-up reports on chondroid lesions of the skull base are rarely presented in the literature. There are virtually no data on natural growth rates of these tumors based on MRI obtained over a period of 10 years or longer. We followed a patient who has had such a lesion for more than 12 years. A non-progressive, slight abducens palsy has been the only associated symptom so far. Even though the patient was operated on for an additional intracranial arterio-venous malformation, clinical features and chromosomal testing excluded Maffucci's syndrome. The MRI follow-up in this case provides an extraordinary perspective on the natural history of chondroid skull base tumors.

Lumbar ependymoma presenting with paraplegia following attempted spinal anaesthesia

Neurological deterioration from intraspinal haematoma following insertion of a spinal needle is extremely rare. We present the case of a 28-yr-old female, who presented with complete paraplegia following attempted spinal anaesthesia for delivery of her third child. Space-occupying iatrogenic spinal haemorrhage from a previously undiagnosed lumbar ependymoma was found to be the precipitating cause. Following laminotomy with blood clot and tumour removal her neurological function improved.

Regeneration of auditory nerve following complete sectioning and intrathecal application of the IN-1 antibody

The cochlear nerve of adult Lewis rats was following microsurgical exposure in the cerebellopontine angle (CPA). The lesions completely interrupted the auditory nerve axons at the lesion site producing ipsilateral deafness in all animals. The rats were then treated with a recombinant Fab fragment of the antibody IN-1 against nerve growth inhibitory proteins for one to two weeks. An age-matched control group of rats was treated with unspecific mouse IgG antibody. Because the cochlear nerve lesions resulted in significant neuronal apoptosis of spiral ganglion cells, neurotrophin-3 (NT-3) was applied to the lesion site immediately post-injury in some rats. Electrophysiological studies were carried out by recording the brainstem auditory evoked potentials (BAEP) before and immediately after the lesion, and at regular intervals up to 2 months after injury. Cochlear nerve fibres were anterogradely traced by horseradish peroxidase (HRP) or biotinylated dextran amine (BDA) injected into the spiral ganglion. The results achieved in this study were consistent with the following conclusions: 1) transection of the adult rat cochlear nerve at the CPA results in functional deafness, disappearance of BAEP, apoptosis of parent axotomized neurons of the spiral ganglion, and interruption of labelled axons close to the lesion site; 2) NT-3 is able to partially rescue axotomized neurons of the spiral ganglion; 3) injured cochlear nerve fibres show a limited spontaneous sprouting and regrowth response which does not lead to BAEP recovery; 4) intrathecal treatment with IN-1 directed against myelin-associated neurite growth inhibitory proteins promotes significant elongation of the injured fibres; and 5) the regenerating fibres seem to navigate to correct targets, and be able to establish synaptic connections for functional recovery as depicted by BAEP examinations.