Retrieval of foreign bodies adjacent to the nervous system: aspects of intra-operative use of ultrasound.

The retention of a foreign body during a surgical procedure or the inadvertent migration of an implant are rare but potentially harmful complications. Especially in the case of the former, the legal situation is unequivocal. Nevertheless, the uncomplicated removal and limitation of the operative trauma may be in the interest of the surgeon. We report and illustrate 2 patients in whom the use of intra-operative ultrasound resulted in the safe and elective removal of an intracranial drill tip in one patient and a contraceptive implant located in the ulnar nerve sheath in the other. The characteristic acoustic shadowing artefact could be demonstrated in both examples. In the first patient, intra-operative magnetic resonance tomography could not be used because of the magnetic artefact, and in the second patient, ultrasound was preferred for reasons of simplicity. Intra-operative ultrasound is an appropriate and easily available tool for detection of small foreign bodies beneath the nervous system. The neurosurgeon should be familiar with the typical characteristics of foreign bodies, which is different from other structures.

Amygdala lesion in temporal lobe epilepsy subjects impairs associative learning of emotional facial expressions.

To investigate the role of unilateral amygdala lesions on processing emotions, 22 drug-resistant temporal lobe epilepsy (TLE) subjects (12 with left-sided and ten with right-sided focus) were tested, after anterior temporal lobectomy or selective amygdalo-hippocampectomy on two associative learning tasks containing emotional and neutral facial expressions, respectively. Volumetric lesion analysis was performed on the basis of 3-D MR images. No effects of lesion side were found in TLE subjects. Taken the extent of amygdala damage into account, an interaction effect could be shown between task (learning of neutral facial expressions versus emotional facial expressions) and group (subjects with little versus considerable amygdala damage), indicating worse performance of subjects with considerable amygdala damage in learning emotional facial expressions. Subjects with considerable amygdala damage were also significantly impaired in learning emotional facial expressions when compared with control subjects.

Differential response of mature TrkA/p75(NTR) expressing human and pig oligodendrocytes: aging, does it matter?

A differential morphological response of mature oligodendrocytes (OL) isolated from human and pig brains to the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) and to the nerve growth factor (NGF) was observed. In both cases, OL regenerate their processes; however, the rate and the extension of the process formation of human OL were behind that of pig OL. Presumably, the advanced age of the human tissue in these experiments might have contributed to this decrease in process formation, an effect that was already observed for rat OL [Yong et al. (1991) J Neurosci Res 29:87-99]. The less effectivity of NGF via TrkA, which was immunocytochemically shown in human OL, and of TPA via the protein kinase C (PKC) pathway, may have its common focus on the mitogen-activated protein kinase (MAPK) cascade. In this context, it was noted that only a few studies on aging of mature OL are available. It is conceivable that age-related changes in the properties of OL could be an important factor for their cellular responsiveness during longer lasting demyelinating diseases such as multiple sclerosis. Hence, this review would like to provide a basis for future investigations on the aging of mature OL. The data presently available suggest a preliminary classification of mature OL into three categories.

Characterization of the contractile and relaxant action of the endothelin-1 precursor, big endothelin-1, in the isolated rat basilar artery.

The presence of functional endothelin converting enzyme (ECE) activity in basilar artery ring segments was investigated by measuring the contractile and relaxant effects of big endothelin (ET)-1. Under resting tension conditions cumulative application of big ET1-1 elicited a concentration-related contraction with the concentration-effect curve (CEC) shifted to the right against ET-1 by a factor of 31 and 29 in segments with the endothelium intact or mechanically removed, respectively. Preincubation with the ET(A) receptor antagonist, BQ123, induced an apparently parallel rightwards shift without affecting the maximum contraction. This shift was more pronounced for ET-1 than for big ET-1. With the putative ECE inhibitor phosphoramidon (10(-3) M) in the bath a small rightwards shift of the CEC for big ET-1 was observed in control segments and a more marked one in de-endothelialized segments. In segments precontracted with prostaglandin (PG) F(2alpha) big ET-1 induced a significant although transient relaxation whereas ET-1 did not. However, in the presence of BQ123 both ET-1 and big ET-1 elicited concentration-related relaxation with a significantly higher maximum effect obtained with big ET-1. The potency was 13 fold higher for ET-1, which is markedly less than that found for contraction. The results, therefore, suggest 1) the presence of functional ECE-activity in the rat basilar artery wall, and 2) differences in the functional ECE activity located in the endothelium and media.

Cisternal S100 protein and neuron-specific enolase are elevated and site-specific markers in intractable temporal lobe epilepsy.

In the brain, S100 protein and neuron-specific enolase (NSE) are mainly found in glial cells and neurons, respectively. We investigated concentrations of S100 protein and NSE in cisternal cerebrospinal fluid obtained during implantation of foramen ovale electrodes in eight patients with temporal lobe epilepsy (TLE). In addition, the meningeal markers cystatin-C and beta-trace as well as total protein were measured. Patients with trigeminal neuralgia (TN) undergoing glycerol rhizotomy served as controls. S100 protein and NSE levels ipsilateral to the site of seizure onset were significantly higher than in TN. Contralateral TLE values were also markedly but not significantly elevated. The meningeal markers cystatin-C and beta-trace protein as well as total protein did not differ in TLE and TN. We conclude that interictal temporal lobe dysfunction corresponds with neuronal and glial marker elevations in the extracellular space and that site-specific elevations may predict the site of seizure origin biochemically.

Using transcranial duplex sonography for monitoring vessel patency during surgery for intracranial aneurysms.

This article reports a method for reliable intraoperative monitoring of blood flow velocities in the basal cerebral arteries during clipping of intracerebral aneurysms. Transcranial color-coded duplex sonography provides practical integration of transcranial Doppler technology with real-time imaging capabilities through the intact human skull. With a computerized sonography system equipped with a 2.5-MHz probe in 50 healthy volunteers, the contralateral internal carotid artery, A1 and A2, as well as M1 and P1 vessels were identified and measured in most patients. In 13 patients undergoing dipping of intracranial aneurysms, the technique successfully imaged 12; it allowed definitive identification of vessels potentially threatened by clipping and not fully visible to the surgeon. Data were easily comparable to preoperative data. This noninvasive, repeatable neuroimaging technique provides useful intraoperative information about intracranial hemodynamics during dipping of intracranial aneurysms.

Blood flow velocities in middle cerebral artery branches after subarachnoid hemorrhage.

In a prospective study, 55 patients were examined by transcranial duplex sonography (TCCS) after subarachnoid hemorrhage (SAH) to determine whether additional transcranial duplex examination on the middle cerebral artery M2 segments would aid in the examination of the MCA stem segment. The mean blood flow velocities and pulsatility index were correlated to the occurrence of delayed ischemic neurologic deficits (DIND). Out of 47 patients included, 21 did not experience any delayed deficit (group I), 15 did (group II), and in 11 the extent to which vasospasm contributed to a neurologic deficit was unclear (group III). The highest blood flow velocity and the greatest increase of mean blood flow velocity on 1 day were significantly higher in groups II and III both in M1 and in M2. In 10 patients in group II, where the onset day of DIND was known exactly, Doppler data indicating ischemia before or at the time of DIND were observed in nine. In eight patients, Doppler of the MCA stem alone would have provided enough information to recognize the risk of symptomatic vasospasm; in one patient, only the M2 Doppler gave an indication of ischemic complication. Transcranial duplex sonography may provide additional information to TCD by accurate delineation of M1/M2 vasospasm and therefore may help plan cerebral angiography and neurointerventional treatment.

Elevated cerebral perfusion pressure and low colloid osmotic pressure as a risk factor for subdural space-occupying hygromas?

BACKGROUND: Space-occupying subdural hygromas are a late complication of severe traumatic brain injury (TBI) and may delay the patient's recovery. To evaluate the risk factors involved, we performed a semiretrospective, -prospective analysis of three groups of patients, which differed with regard to the techniques used in the management of their cerebral perfusion pressure (CPP) and colloid osmotic pressure (COP) to determine the occurrence of space-occupying subdural hygromas. PATIENTS AND METHODS: Between 1989 and 1997 we examined 696 patients after a severe TBI: Group 1. 1989-1994 mean CPP: 67 (elevated for therapeutic reasons by catecholamines, if necessary), mean COP: 19. Group 2. January 1995-October 1996, mean CPP: 77, mean COP: 20. Group 3. November 1996-December 1997, mean CPP: 79, mean COP: 23 (elevated for therapeutic reasons by infusions of colloids). The groups were comparable for other criteria. RESULTS: Compared to Group 1, Group 2, with a high CPP but lower COP, showed a significantly higher (p < 0.01; chi2-test with correction of Yates) percentage of posttraumatic subdural hygromas with space-occupying aspects, clinical signs of bradycardia, hypertension and impaired consciousness requiring surgery (Group 1: 1.75%; Group 2: 10.46%; Group 3: 0%). In Group 3 we saw no patient with a space-occupying hygroma. CONCLUSION: We conclude that iatrogenic elevated CPP, which has been reported to be helpful in preventing secondary ischemic damage after a severe TBI, may be harmful to a patient if the COP is not maintained within physiological ranges.

Self-help activities of brain tumour patients and their relatives.

BACKGROUND: To date, little is known about self-help activities including the acquisition and distribution of information among brain tumour patients and their relatives. The aim of our study was to elucidate patient characteristics, methods of networking and the impact on further treatment. METHODS: A German questionnaire was distributed at nationwide patient meetings and via internet forums. It was returned electronically or by regular mail. RESULTS: Mean age of the 129 patients was 43.2 years. Mean age of the 140 relatives (94% family members) answering the questionnaire was 42.6 years. 51% of the patients and 60% of the relatives had a university degree. 61% of the patients suffered from high-grade tumours, and 80% of the relatives were caring for high-grade tumour patients. The higher the grade of the tumour, the earlier self-help was begun after diagnosis. The majority of the patients (36%) and their relatives (54%) spent between 1-4 h per week on self-help activities. More than 80% used the internet, but more than 85% used print products for the acquisition of information. More than 50% felt that they were not given enough information by their treating physician. Motives for self-help were the acquisition of "independent" information and psychological relief from an exchange with other tumour patients. The vast majority was satisfied with the results obtained, and more than four out of five who responded to the questionnaire exchanged information with other patients. The current therapy was influenced by self-help in more than 50% of cases. CONCLUSION: Physicians treating patients with brain tumours face a subgroup of well-educated people aiming to independently verify and possibly supplement and/or modify their prescribed care. With the steadily increasing use of internet resources, this approach can be expected to expand. Physicians should be prepared to deal appropriately with this subgroup of patients and their relatives to ensure that self-help activities support but do not endanger optimal care.

Intra-operative diagnosis and image-guided management of an intracerebral haemorrhage occurring during ultrasound-guided biopsy.

Haemorrhagic complications occurring after burr-hole procedures are diagnosed only in symptomatic patients or when postoperative imaging is performed routinely. We report the development of an intracerebral haematoma which occurred during ultrasound-guided burr-hole biopsy. Real-time ultrasound through the same burr-hole enabled us to determine the dynamics of the bleeding and its terminal volume. The operation was finished without further complications and the patient did not experience an impairment of her neurological state. Intra-operative ultrasound is capable of detecting "invisible" complications during burr-hole procedures.

Intrinsic brainstem tumours in adults: results of microneurosurgical treatment of 16 consecutive patients.

Intrinsic brainstem tumours in adults have a poor prognosis and surgical resection is rarely performed. Encouraged by successful operations on children performed in our department, we began a more aggressive strategy of open operations. Between 1986 and 1997, we operated upon 16 consecutive patients over 16 years of age (five female, 11 male, mean age 36.9 years) who were suffering from intrinsic tumours located in the pons and/or medulla oblongata. The extent of first open resection was 80 - 100% in two of the cases and more than 50% in nine cases. The mean survival time after the first occurrence of symptoms was 88.1 (median 34.5) months, and 39.9 (median 11) months after the first open operation. The rate of 5-year survival from the first occurrence of symptoms was 37.5% (25% after the first open surgical procedure). Thirteen out of 16 patients died within the follow-up period of at least 6.3 years, two of them within the immediate postoperative period. Eleven patients experienced a postoperative deterioration of symptoms from which only four recovered. Eight patients had from WHO grade II astrocytoma and a similar course as patients with higher-grade gliomas (n = 4). Our results indicate that open microneurosurgery for intrinsic brainstem tumours is of questionable benefit for the patient. Although surgery offers the advantages of reliable confirmation of histopathology and may be associated with prolonged survival, neurological deterioration was common and, unlike in paediatric patients, often irreversible.

Minimally invasive neurosurgery within a 0.5 tesla intraoperative magnetic resonance scanner using an off-line neuro-navigation system.

BACKGROUND AND PURPOSE: We evaluated an advanced concept for patient-based navigation during minimally invasive neurosurgical procedures. METHODS: An infrared-based, off-line neuro-navigation system (LOCALITE, Bonn, Germany) was applied during operations within a 0.5 T intraoperative MRI scanner (iMRI) (Signa SF, GE Medical Systems, Milwaukee, WI, USA) in addition to the conventional real-time system. The three-dimensional (3D) data set was acquired intraoperatively and up-dated when brain-shift was suspected. Twenty-three patients with subcortical lesions were operated upon with the aim to minimise the operative trauma. RESULTS: Small craniotomies (median diameter 30 mm, mean diameter 27 mm) could be placed exactly. In all cases, the primary goal of the operation (total resection or biopsy) was achieved in a straightforward procedure without permanent morbidity. The navigation system could be easily used without technical problems. In contrast to the real-time navigation mode of the MR system, the higher quality as well as the real-time display of the MR images reconstructed from the 3D reference data provided sufficient visual-manual coordination. CONCLUSION: The system combines the advantages of conventional neuro-navigation with the ability to adapt intraoperatively to the continuously changing anatomy. Thus, small and/or deep lesions can be operated upon in straightforward minimally invasive operations.

Internet-based interaction among brain tumour patients. Analysis of a medical mailing list.

Patients and their care providers are increasingly turning to the internet for information. Being faced with this information of very heterogeneous quality, the physician would do well to be informed about the common internet information sources. We investigated the e-mails of a mailing list (or "support group") serving about 380 brain tumour patients and their care providers. The mails were obtained from an archive and grouped according to their topic. Within 6 months, 3,272 e-mails were distributed to every group member. Alternative treatments were the most frequently discussed topics (15 %). These discussions dealt with serious new strategies as well as dubious drugs and methods. A critical attitude towards "quacks" was common, but not the rule. More than 10 % of the mails dealt with debates about therapeutic strategy and about symptoms. The individual course of the participants' illness was often reported very frankly. Emotional support between members played another great role in the support group. Criticism of physicians was rare compared to recommendations of specific therapists (3 % vs. 4 %) and included lack of empathy or sensibility and poor communication between physicians. The brain tumour mailing list is a communication medium for brain tumour patients and their care providers, which distributes and reproduces information of heterogeneous quality. The physician faced with this information should be unbiased but cautious.

The value of transcranial duplex sonography in the management of patients subsequent to surgery for middle cerebral artery aneurysms.

OBJECTIVE: We intended to evaluate the value of transcranial color-coded duplex sonography (TCCS) in the management of patients after clipping of an aneurysm of the middle cerebral artery. Question was whether this method was able to predict poor clinical outcome by detection of local circulation disorders in the postoperative course. METHODS: A series of 15 consecutive patients was examined daily by TCCS. Special attention was paid to the branches of the middle cerebral artery distal from the clip (M2 branches). We correlated the TCCS results to the clinical outcome and occurrence of infarction on CCT. RESULTS: In six patients, one or more M2 branches could not be found in the immediate postoperative course, but reappeared after a period of 1-12 days in five patients. The three patients with a missing signal for more than 4 days suffered from infarction of the dependent territory and permanent neurological deficit not due to vasospasm of the middle cerebral artery. In the nine patients with constant TCCS signals, there was only one infarction due to pre-hospital systemical hypotension. CONCLUSION: TCCS cannot give exact postoperative information about incidental vessel occlusion during surgery for MCA aneurysms because M2 branches can remain invisible for some days without being occluded, but this invisibility seems to be coupled with ischemic complications.

Intra-axial endophytic tumors in the pons and/or medulla oblongata. II. Intraoperative findings, postoperative results, and 2-year follow up in 25 children.

Between July 1987 and June 1994 we operated upon 30 consecutive children suffering from endophytic intra-axial tumors located in the pons and/or medulla oblongata. The 25 children operated on between July 1987 and October 1993 whose postoperative course could be assessed for a minimum of 2 years after operation were included in this study. Operability of a brain stem tumor was shown to be independent of its size. A gross tumor resection between 80% and 100% could be performed in half these cases, and subtotal or partial resection in the other half. The radicality of resection was not influenced by tumor histopathology, but was dependent on intraoperative findings relating to its consistency, infiltration, and visibility. On follow up, 15 of the 25 children were found to have died within the period of 2 years. Two children died in the immediate postoperative period (at 2 days and 2 weeks after surgery), of acute brain stem swelling and an unsuspected bleeding disorder, respectively. The other 13 of these 15 children died of tumor progression between 1 and 19 months after operation, with a median survival time of 9 months. In the group of the surviving 10 children the histopathology was grade I astrocystoma in 6 cases, angioma in 2 cases, and grade II oligodendroglioma and grade II ependymoma in 1 case each. Postoperatively, most of the children showed some increase in their preoperative deficits, but recovered after 2-3 months. After 2 years, 10 of the 25 children who were followed up are alive and 9 of them attend regular school or kindergarten.

A stable positioning for patients requiring large calvarial exposure for surgical correction of cranial synostosis.

We present a simple and elegant method of positioning the child's head for repair of craniosynostosis. The Sugita head holder allows large exposure of the calvarium with little risk of injury, dislocation or extensive blood loss caused by venous compression. We operated upon 37 patients (age range, between 3 and 132 months, median age 7 months) and did not observe any complication or lesion caused by positioning.

Peroperative cardiovascular stability during brainstem surgery. The use of high-dose methylprednisolone compared to dexamethasone. A retrospective analysis.

BACKGROUND: In neurosurgical procedures within brainstem structures, corticosteroids are routinely administered to prevent oedema and to reduce intraoperative trauma. After replacing the routine administration of dexamethasone (DX) by high-dose methylprednisolone (MP) during surgery for tumours within brainstem structures, a decreased incidence of intraoperative haemodynamic instability events was observed. To test this hypothesis, a retrospective analysis was performed. METHODS: Peroperative data of 62 surgical procedures of brainstem tumours were retrospectively analysed with respect to haemodynamic instability requiring changes in surgical strategy and/or emergence medication with vasoactive drugs. Severe changes in haemodynamic parameters were defined as a significant increase or decrease in heart rate and/or mean arterial blood pressure greater than 30% compared to baseline values. From 1988 to 1994, intravenous dexamethasone was given peroperatively in 33 patients. After a bolus of 1 mg kg(-1) body weight (BW) 30 min preoperatively, 0.2 mg kg(-1) were given every 4 h. From 1994 until now, methylprednisolone was administered instead of dexamethasone in 29 patients. After an initial bolus of 30 mg kg(-1) BW immediately before surgery, 5.4 mg kg(-1) h(-1) were given 23 h postoperatively. RESULTS: The results of this retrospective analysis suggest that the number of operations with episodes of bradycardia, arterial hypotension (P<0.05), tachycardia and arterial hypertension (P<0.005) was significantly decreased in the group of patients treated with high-dose methylprednisolone. CONCLUSION: The retrospective analysis of the clinical data showed that the routine use of high-dose methylprednisolone was associated with a decreased incidence of haemodynamic instability in a selected group of patients undergoing brainstem surgery. This finding has to be proven in prospective double-blind controlled studies.

[Transcranial color-coded real time ultrasound. An improvement in patient monitoring in the neurosurgical intensive care unit?]. / Die transkranielle farbkodierte Real-Time-Sonographie. Eine Verbesserung der Patientenüberwachung auf der Neurochirurgischen Intensivstation?

It is still not always possible to detect in time early intracranial complications in neurosurgical critical care patients. In addition, the exact definition of the lesion requires an often life-threatening transport to the CCT. Hence, there is still a need for improved bedside monitoring. New developments in ultrasound technique enable us not only to get a two-dimensional image of intracranial parenchymatous structures through the intact bone but also to visualise, by means of colour-coding, the blood flow the intracranial vessels. In 70 mostly neurotraumatised patients we found that this method is helpful in solving diagnostic or therapeutic problems without the patient having to leave the intensive care unit.