Nonconvulsive status epilepticus as a possible cause of coma in neurosurgical intensive care.

Nonconvulsive status epilepticus (NCSE) can occur in comatose patients without clinical signs of seizure activity. We evaluated the occurrence of NCSE in patients who were admitted to our neurosurgical intensive care unit between 1998 and 2000. EEGs were obtained from 158 patients with head trauma, spontaneous bleeding or brain tumour. Patients with clinically apparent seizure activity or no electrophysiological signs of seizure activity were excluded from the study. Epileptiform activity was seen in 28 out of 158 patients. 11/28 of these patients had a Glasgow-Coma-Scale (GCS) Score below 9 and showed continuous epileptiform discharge without clinical signs of seizure activity (NCSE). The clinical status of 4 of these 11 NCSE patients improved after initiation of anticonvulsive medication. NCSE may be an under-recognised cause of coma in neurosurgical intensive medicine. EEG should be included in the routine evaluation of comatose patients, even if clinical seizure activity is not apparent.

The hour-glass model of corpus callosum injury.

In this retrospective study, the authors analyze the frequency, anatomical distribution and the clinical outcome of 44 patients after severe head injury, with and without lesions of the corpus callosum (CC). 44 patients with severe head injury (GCS<9 on admission), who were admitted to the intensive care unit of the Department of Neurosurgery after trauma, underwent early MR-tomography (T1, T2 and FLAIR sequences) in addition to CCT performed on admission. CC lesions were found in about 1/3 of patients with severe head injury. Posterior (splenium) lesions of the CC were three times more common than anterior lesions. Patients with CC injury were much younger compared to patients without CC injury (25 versus 34 years). The Glasgow Outcome Scale (GOS) score after six months was poor (death, persistent vegetative state, severe disability, GOS>3) in all patients with CC injury when compared to patients without CC injury (GOS<4). CC lesions are an important parameter in the assessment of severe brain trauma, hinting at the mechanism of injury as well as the outcome of patients. If a patient does not awake after blunt head injury, MRT scans (including FLAIR sequences) are indicated. A CC lesion alone is not the cause of prolonged coma but indicates a severe diffuse injury resulting in functional deorganization of the brain. The mechanisms of CC injury are discussed and a new pathophysiological model, based on the hour-glass analogy, is presented.

Treatment strategies of space-occupying intradural metastases of the cauda equina of nonneurogenic origin.

BACKGROUND: Compressive intradural metastases of the cauda equina are a rare site of metastatic spread in systemic cancer. So far, only few reports have been published with conflicting statements concerning a surgical versus nonsurgical approach. METHOD: Five patients with symptomatic space-occupying intradural metastases of the cauda equina were analyzed retrospectively, focusing on the influence of surgical intervention on pain relief, neurological outcome and thus the patients' quality of life. FINDINGS: At the time of diagnosis, all patients were in an advanced metastatic state. Surgical resection was the primary treatment in four patients and radiotherapy in one. Despite infiltration of the cauda rootlets, gross total tumour resection could be achieved in two of the four patients treated surgically. Functional outcome was beneficial in these patients with marked and immediate relief of pain and improvement of motor function even following incomplete tumour resection. CONCLUSIONS: Surgical treatment of compressive intradural metastases of the cauda equina seems to be feasible with low operative risk and with the potential benefit of an immediate relief of pain and improvement in motor function and thus an increase in quality of life.

Incidence and outcome of traumatic brain injury in an urban area in Western Europe over 10 years.

INTRODUCTION: Valid epidemiological data on incidence and outcome of traumatic brain injury (TBI) show great variability. A study on incidence, severity and outcome of TBI was conducted in an urban area of one million inhabitants. MATERIALS AND METHODS: 130,000 prehospital emergencies were screened for TBI. INCLUSION CRITERIA: Glasgow Coma Scale (GCS) score or=2 with confirmed TBI via appropriate diagnostics. RESULTS: Annual incidence was 7.3/100,000. Overall mortality rate was 45.8%: 182 (28%) were prehospital deaths, 116 (17.8%) patients died in hospital. Two hundred and fourteen of 352 (60.8%) surviving patients were sufficiently rehabilitated at discharge [Glasgow Outcome Scale (GOS) score = 1], but 138 patients (39.2%) survived with persisting deficits. GOS was associated with initial GCS and AIS(head). CONCLUSION: The incidence of TBI was lower compared to the literature. The overall mortality was high, especially prehospital and early in-hospital mortality rates.

Severe inflammatory reaction of the optic system after endovascular treatment of a supraophthalmic aneurysm with bioactive coils.

We report on a patient who, after a symptom-free interval, developed severe vision impairment and whose MR imaging demonstrated extensive edema in the central nervous tissue neighboring the treated aneurysm. To our knowledge, this is an unreported complication of endovascular treatment of aneurysms.

Small keyhole transuncal foraminotomy for unilateral cervical radiculopathy.

Interbody fusion after anterior discectomy may lead to acceleration of degenerative changes at adjacent levels. Although the posterior approach preserves the motion segment, decompression of the nerve root is indirect if "hard disc prolaps" is the main cause. Recently, a technique of microsurgical anterior cervical foraminotomy for the treatment of radiculopathy with preservation of the segment mobility was published. In this study, we present this technique with several modifications.Thirteen patients - 5 men and 8 women with an average age of 49 years - with unilateral radiculopathy resistant to conservative treatment underwent microsurgical anterior foraminotomy via a small keyhole transuncal approach. The base of the uncinate process (UP) was directly drilled in the trajectory to the intervertebral foramen without destroying the disc tissue. The vertebral artery between the transverse process was not exposed. Furthermore, the functional anatomy of the uncovertebral joint remained largely intact. All patients experienced complete relief of radiating pain. A cervical collar was not used. Mean follow-up time was 19 months. The mobility of the operated segment was preserved in each patient. No instability of the cervical spine was seen. The microsurgical anterior foraminotomy via a small keyhole transuncal approach is safe, minimally invasive, and represents an effective method to treat unilateral cervical radiculopathy caused by disc prolaps and/or uncovertebral osteophytes. Additionally, the segment mobility is preserved and prevents the acceleration of degenerative changes at adjacent levels.

F-wave amplitudes indicate evolving spinal autonomy during spontaneous recovery of hindlimb function in rat spinal cord contusion.

STUDY DESIGN: Experimental rat model of spinal cord contusion. OBJECTIVES: To reveal the extent of spinal autonomy contributing to recovery of hindlimb function. SETTING: Experimental laboratory of a neurosurgical university department. METHODS: F-wave amplitudes as a probe for spinal cord excitability were recorded from both sciatic nerves (lumbar segments L2-L5) before and after an experimental spinal cord contusion performed in the lower thoracic spinal cord. Additionally, transcranial electrically motor evoked potentials from the hindlimbs and cerebral somatosensory potentials evoked by sciatic nerve stimulation were recorded. Clinical evaluation of hindlimb function was done regularly for survival periods of 3 and 50 days, respectively. Electrophysiological testing was performed immediately prior and after lesioning of the cord and at the endpoint of survival periods. RESULTS: Hindlimb function recovered from a mean Basso-Beattie-Bresnahan score of 5.6 on day 1 to 9.2 on day 3 (3-day-survivors) and from 7.7 to 17.2 on day 50 (50-day-survivors). This was accompanied by a significant increase of F-wave amplitudes on day 50 compared to baseline values, whereas amplitudes of somatosensory and motor-evoked potentials remained significantly depressed. CONCLUSION: Recovery of hindlimb function may at least in part be attributed to evolving spinal autonomy, which can be assessed by F-wave amplitudes.

Spinal epidural abscess: prognostic factors and comparison of different surgical treatment strategies.

BACKGROUND: Spinal epidural abscess (SEA) is a rare but potentially devastating disease requiring immediate surgical intervention and appropriate antibiotic treatment. The standard approach to decompress SEA is laminectomy. No report covers comprehensively the indications for the less invasive interlaminar approach, the usefulness of intra-operative ultrasonography and the suspected benefit of inserting a suction-irrigation drainage. METHOD: A retrospective evaluation of the medical and radiological data was undertaken in 27 consecutive patients with SEA operated on during a period of 10 years by a dorsal approach. Factors influencing outcome were evaluated with special regard to different surgical strategies concerning the invasiveness of the operative approach, the use of intra-operative ultrasound and the use of different drainage systems. FINDINGS: Outcome was mainly determined by the pre-operative neurological condition and the localization of the abscess. Recurrence rate was dependent on the longitudinal extent of the mass and the intra-operative finding of granulation tissue, but not on the administration of a postoperative suction-irrigation drainage. An interlaminar approach was equally matched to a decompression by laminectomy in lumbar SEA concerning the incidence of residual/recurrent abscess formation. In concomitant spondylodiscitis, laminectomy bore the risk of the formation of a postoperative kyphotic deformity. The use of intra-operative ultrasound allowed the visualization of hidden inflammatory masses and, thus, reduced the rate of residual abscess formation. CONCLUSION: An interlaminar approach should be considered instead of laminectomy in lumbar SEA and in impending anterior column instability due to spondylitis. Intra-operative ultrasound is a beneficial aid for the determination of the extent of decompression during surgery and is practicable even through a narrow interlaminar bony window. The insertion of postoperative suction-irrigation drainage had no beneficial effect on outcome but bore the risk of epidural fluid congestion.

[Optimization of microsurgical operation technique to insert auditory brainstem implants, taking into account the results of a morphometric study]. / Morphometrische Studie zur Optimierung der Implantationstechnik zentraler Hörprothesen.

STATE OF THE ART: The surgical placement of auditory brainstem implants to stimulate the cochlear nuclear region in patients with acquired bilateral retrocochlear deafness allows limited restitution of hearing. However, there have been few studies on the topographical relations in the target region, particularly the floor of the IVth ventricle. TOPIC OF THE STUDY: Is it possible to obtain more precise anatomical data in order to improve the surgical approaches and techniques for the placement of auditory brainstem implants? AIMS. To obtain a more precise topo- anatomical orientation in the target region for microsurgical lateral and midline approaches or a stereotactic operative strategy. METHODS AND RESULTS: Landmarks for the placement of an auditory brainstem implant via the IVth ventricle were examined and measured in a series of formalin-fixed human brainstems ( n=28). These data, and knowledge of their variability, allow a more precise surgical lateral approach. It is essential to precisely localise the target region, as it can only be partly discerned under the microscope during an operation. For this reason, to date its precise localisation has been determined only electrophysiologically. CONCLUSION: Exact target localisation improves safety. From an anatomical point of view the midline approach gives the chance to enlarge the indication spectrum for an implant. The anatomical data obtained here could also be integrated into a stereotactic surgical strategy.

CT-guided percutaneous aspiration of Tarlov cyst as a useful diagnostic procedure prior to operative intervention.

Tarlov or perineural cysts are lesions of the nerve root most often found in the sacral region. Several authors recommend surgical treatment of symptomatic Tarlov cysts. However, successful surgical treatment is dependent on appropriate patient selection. In this article, we report three cases of a sacral perineural cyst, causing sciatic pain, and emphasize the usefulness of CT-guided percutaneous aspiration as an important diagnostic and prognostic procedure prior to definitive operative treatment.

Visually evoked changes of blood flow velocity and pulsatility index in the posterior cerebral arteries: a transcranial Doppler study.

OBJECTIVE: Transcranial Doppler sonography (TCD) can detect visual evoked blood flow responses non-invasively and continuously with high temporal resolution. While the mean flow velocity response to visual stimuli is well documented, the response of the pulsatile characteristics of the waveform is less well known. METHOD: We examined the changes of blood flow velocity and pulsatility index (PI) in the posterior cerebral artery (PCA) in 50 healthy volunteers. TCD responses were measured in response to metabolic activation of the visual cortex by visual stimulation. RESULTS: A specific, stimulus-related increase of the mean flow velocity (MFV) in the PCA was found. The intensity of the blood flow response was significantly influenced by the complexity of the stimulus. During complex visual stimulation we found a mean flow velocity (MFV) increase of 29.4 % from the baseline in the subjects. However, a stimulus-related decrease was observed in the pulsatility index (PI); although the mean PI with closed eyes during baseline measurement was 1.18 (SD 0.27), on average, it fell significantly to 0.95 (SD 0.23) with the alternating chessboard and 0.82 (SD 0.22) during the complex stimulus condition. The relative decrement of the pulsatility index with increasing complexity of the visual stimulus is highly significant, with values of -19.5 % and -30.5 % compared to the baseline. CONCLUSION: These findings demonstrate the inverse correlation between MFV response and pulsatility index in the PCA. We assume that this decrease of the PI in the PCA may reflect the reduced regional vascular resistance in the visual cortex during visual stimulation.

[Diagnosis, treatment and progress after frontal lobe injury]. / Diagnostik, Therapie und Verlauf nach Frontalhirnschädigung.

The comprehensive assessment of a frontal lobe injury is one of the most complex problems in diagnosis and treatment due to the variability of nature, extent and effect of various disorders of higher cerebral functions, i. e. impairment of the ability to act systematically, attention, motivation and emotionality. This brings about considerable differences in assessing and judging the effects of frontal lobe syndromes. Impairments of initiation, planning and carrying out of actions, of impulse control, attention, memory and self-perception often manifest in disorganised and dissocial behaviour which brings about serious effects in many fields of social adaptability. Deeper neurological insights in nature and effects of these deficiencies and improved diagnostical methods and concepts of intensive-care treatment as well as the improved understanding in the necessity of a longterm rehabilitation program have led to the development of specific strategies concerning the dealing with the patient, the counseling of the social environment, especially of the relatives, and the treatment of the patient's symptoms. In the course of acute and rehabilitative treatment the patient normally has to develop strategies of habituation and adaptation to his social environment, furthermore techniques of compensation as well as an improvement of personal resources including attention, memory and planning of actions. The ability of self-control ought to be improved by training of behavioural strategies leading to an increased independence. The success of treatment varies distinctly from individual to individual. As a rule, basic capabilities in the scope of higher brain functions as well as executive and behavioural abilities can be improved. However, a restitutio ad integrum of all dysfunctions is very rare.

Influence of TachoComb in comparison to local hemostyptic agents on epidural fibrosis in a rat laminectomy model.

This animal experimental study was designed to examine the effects of TachoComb, a fixed combination of collagen with tissue adhesive, as an interposition membrane on the development of spinal epidural fibrosis in comparison to other hemostyptic materials. In 10 Wistar rats, four laminectomies were performed at lumbar and sacral vertebrae. Alternately, a piece of TachoComb, Spongostan, or Tabotamp was placed into each laminectomy site. One laminectomy site served as an empty control (n = 10). 8 weeks later, the animals were sacrificed, and the spinal column including surrounding muscle tissue was removed en bloc from each rat and fixed in formaldehyde. After decalcification and staining the specimens were graded by a neuropathologist in a blindfold test for severity of epidural fibrosis as "light-moderate" or "marked". Epidural scarring of variable density was seen in all laminectomy sites. Light epidural fibrosis, without any adhesion to dura, as only noted in cases after application of TachoComb (n = 4/10) and Spongostan (n = 1/10). All other slices showed marked epidural fibrosis with dura adherence regardless of the implanted material. Statistical analysis revealed significantly lower epidural fibrosis after application of TachoComb compared to all other groups (p < 0.05). In this series, TachoComb is more effective in reducing the epidural fibrosis than Spongostan, and Tabotamp. However, complete prevention of scar tissue formation was not achieved.

Intermediate and long-term outcome in traumatic brain injury is not influenced by additional multiple organ injury.

BACKGROUND: This investigation aims at evaluating the influence of additional multiple organ injury in traumatic brain injury on the outcome in terms of the ability to perform the activities of daily life, of the need of care, and of job ability. METHODS: 62 victims (male to female ratio 4 : 1; age range 15-68 years) of traumatic brain injury were studied. Group 1 (n = 24) consisted of patients who suffered from traumatic brain injury with additional multiple organ injury, group 2 (n = 38) comprised patients with isolated brain injury. Outcome was assessed at 6 and 12 months after trauma by means of different rehabilitation scores. RESULTS: After 6 as well as after 12 months, the majority of both groups were independent in the activities of daily living. Furthermore, no differences were observed concerning the need of care. Job ability was almost equal for both groups. CONCLUSION: Additional multiple organ injury does not pertain to prognosis of traumatic brain injury.

Functional and psychosocial outcome one year after severe traumatic brain injury and early-onset rehabilitation therapy.

This study evaluates the impact of early-onset continuous rehabilitation treatment on the 1-year outcome of patients after severe traumatic brain injury. Immediately after recovery from mechanical ventilation, a total of 48 patients underwent a complex early rehabilitation treatment until they were discharged from hospital and local ambulant care was deemed sufficient. The follow-up examination took place 12 months after trauma. Data reveal that at 1 year 91.6% of the patients were completely or restrictedly independent of care and capable of carrying out activities of daily living, although they frequently were still suffering from marked behavioural and also from certain sensorimotor deficits. Only 45.8% of the patients were obviously able to work without restrictions or had returned to work. In those subjects who were not or only very restrictedly able to work, behavioural and speech deficits were significantly more frequent. Behavioural and speech deficits seem to represent the major cause that hinders professional reintegration. Rehabilitation therapy therefore should be specifically directed to improve these deficits.

Relevance of magnetic resonance imaging for ventricular endoscopy.

OBJECTIVE: Endoscopic procedures may represent an alternative to microsurgery or shunt operations in intra- or paraventricular pathologies. However, the operative results mainly depend on the selection of suitable patients. In the present study of 30 patients with occlusive hydrocephalus, the relevance of differentiated magnetic resonance (MR) imaging for evaluation of the pathophysiological and anatomic prerequisites was investigated. PATIENTS AND METHODS: Apart from conventional axial T(2) -weighted turbo spin echo (TSE) sequences (TR/TE 2126/100 ms) and T(1) -weighted spin echo (SE) sequences (TR/TE 450/15 ms) with and without the administration of Gd-DTPA, the MR protocol included sagittal and coronal thin-sliced T(2) -weighted TSE sequences, cardiac-triggered (TR/TE > 2700/120 ms, slice thickness 3.0 mm) or in volume technique (TR/TE 4000/180 ms, slice thickness 1.4 mm). For the visualization of CSF flow, a sagittal and axial phase-contrast-multi-heart-phase (PCMHP) measurement with 16 phases per cardiac cycle and flow sensitivity in the cranio-caudal direction (TR/TE 18/9.5 ms and 14/9.5 ms) was performed. RESULTS: The combination of imaging and flow sequences provided most information about the extent and the etiology of hydrocephalus. An obstruction of CSF pathways could be detected by the absence of flow voids in T(2) -weighted TSE sequences or of flow signals in PCMHP sequences. The size of the foramen of Monro and of the third ventricle could be evaluated in thin-sliced T(2) -weighted TSE sequences, for the foramen of Monro in coronal and sagittal and for the third ventricle in coronal and axial slice direction, respectively. The basal structures of the third ventricle, including its floor, the infundibular recess, the mamillary bodies, and the basilar artery, could be best identified in sagittal thin-sliced T(2) -weighted TSE scans, cardiac-triggered or in volume technique. CONCLUSION: In occlusive hydrocephalus, a differentiated MR protocol with thin-sliced T(2) -weighted TSE sequences and phase-contrast sequences allows a very precise estimation of the pathophysiological and the anatomic prerequisites for endoscopic procedures. Furthermore, MR imaging can be used for the follow-up documentation of ventriculo-cisternostomies, -cytostomies, or openings of other membranes.

Rehabilitation of hearing and communication functions in patients with NF2.

Most patients with neurofibromatosis type 2 (NF2) lose hearing either spontaneously or after removal of their neurofibromas. The patient may benefit from conventional hearing aids if, due to modern microsurgery and intraoperative monitoring the integrity of the cochlea and the 8th nerve is preserved. With lost auditory function but preserved electrical stimulibility of the 8th nerve a cochlear implant may be appropriate. But if the patients have no remaining 8th nerve to stimulate, there is no benefit from cochlear implants. Until some years ago, vibrotactile aids, lip-reading, and sign language have been the only communication modes available to these patients. With auditory brain stem implants it is now possible to bypass both the cochlea and the 8th nerve and to stimulate the cochlear nucleus directly. Stimulation of the devices produces useful auditory sensations in almost all patients. Testing of perceptual performance indicated significant benefit from the device for communication purposes, including sound-only sentence recognition scores and the ability to converse on the telephone. Also lip-reading is significantly improved with brain stem implants. The successful work of an auditory brainstem program center depends very much on the close interdisciplinary collaboration between the Departments of Neurosurgery and ENT-surgery. In the future new developments like speech processing strategies and new designed electrodes accessing the complex tonotopic organization of the cochlear nucleus may further improve rehabilitation in these patients who would have been deaf some years ago.

Early rehabilitative concepts in therapy of the comatose brain injured patients.

OBJECTIVES: To evaluate the changes of vegetative parameters and behavioural assessment in comatose patients after severe brain injury during the Multimodal-Early-Onset-Stimulation (MEOS) in early rehabilitation. MATERIAL AND METHODS: We studied 16 predominantly male (3:1) patients, age mean 43.6 (16-77) years. Mean coma duration was 22.2 (8-41) days, therapy duration (MEOS) 9.8 (1-30) days. The initial GCS was 6.6 (3-9), KRS 5.3 (0-15). Including criteria for therapy: Severe head trauma, coma for at least 48 hours (GCS < 8), vegetative stability, normal intracranial pressure, abandon of mechanical ventilation, sedation and severe infections. MEOS was finished in achieving GCS > 9, follow-up investigations were made after 2 years. RESULTS: We identified significant changes in two vegetative parameters (heart/respiratory frequencies), even in deep coma (GCS 3-4). Most significant changes were caused by tactile and acoustic stimulation. Standardized behavioural assessment turned out to be particularly advisable in cases of medium coma (GCS 5-7). Stimulation of tactile and acoustic senses resulted mainly in mimical, head and eye movements. Follow-up was possible in 14 patients: One remained in a vegetative state (GOS 2), two exhibited severe neurologic/neuropsychologic deficits, depending on care (GOS 3), six substained major functional deficits (GOS 4), at though they were able to perform the tasks of daily life on their own, three patients reached GOS 5. Two returned to their former jobs. DISCUSSION AND CONCLUSION: The present results indicate that stimulation therapy should be based on a close observation of patterns of behaviour, and, at least in deep coma stages, involve the registration of vegetative parameters. It may be sensitive to identify parameters predicting a favourable or unfavourable outcome. Preliminary data seem to support the hypothesis that the absence of any response to external stimuli is indicative of an unfavourable outcome.

High cervical spinal cord stimulation (CSCS) increases regional cerebral blood flow after induced subarachnoid haemorrhage in rats.

The effects of high cervical spinal cord stimulation (cSCS) on regional cerebral blood flow (rCBF) were investigated after experimentally induced subarachnoid haemorrhage (SAH) in rats by the means of (99m)Tc-HMPAO. The experiments were carried out on a total of 24 Wistar rats, divided in three groups [group I: control without SAH, group II: SAH, group III: SAH and cSCS]. (99m)Tc-HMPAO was administered intravenously (group II/group III) 48 hours after induction of SAH. In group III, (99m)Tc-HMPAO was given after 3 hours of cSCS. All animals were sacrificed 30 minutes after application on (99m)Tc-HMPAO. Radioactivities were determined in blood, cerebrum and cerebellum. The ratio cerebrum/blood and cerebellum/blood was calculated to ascertain "extraction rate" in the sample differentially. The following mean values were calculated for the cerebellum/blood ratio: Group I: 1.06, SD: 0.21; Group II: 0.66, SD: 0.21; Group III: 1.00, SD: 0.37. Comparing the mean values a highly significant difference could be found between group II and III (p = 0.007) and between group I and II (p = 0.0019), respectively. Calculations of the cerebrum/blood ratio revealed similar results. After SAH cSCS enhances cerebral and cerebellar blood flow in rats. Possibly, cSCD constitutes a new therapeutic approach in the treatment of disturbed regional cerebral blood flow after SAH.

ODC mRNA as a prognostic factor for predicting recurrence in meningiomas.

In proliferating neoplastic cells, activity of the enzyme ornithine decarboxylase (ODC) increases. Among other brain tumors, ODC activation could also be observed in meningiomas. In the present study, we have investigated ODC gene expression in primary and recurrent meningiomas at the transcriptional level. ODC mRNA (messenger ribonucleic acid), ODC activity, number of mitoses, and Ki-67 index as a marker for nuclear proliferation were quantified in three different groups of meningiomas: tumors without recurrence in a 8.4 years median follow-up period, tumors with recurrence within a median follow-up of 3.0 years, and their corresponding recurrent tumors. ODC mRNA level was significantly higher in meningiomas with later recurrence as compared to meningiomas without recurrence (p < or = 0.01), whereas it declined in the recurrences of the second group (p < or = 0.001). In contrast, ODC activity showed no difference between the two groups of primary tumors, but a significant increase of enzyme activity could be observed in the recurrences as compared to the correponding primary tumors (p < or = 0.001). Likewise, an increase of the Ki-67 index could be detected in the recurrent group (p < or = 0.001). These results suggest that ODC mRNA may represent a prognostic factor for predicting recurrence in meningiomas.