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M R Gaab

Publications and source records attributed to M R Gaab.

At least 37 records · Page 2Linked to original sources
PubMed1999

Surgical decompression for traumatic brain swelling: indications and results.

OBJECT: Decompressive craniectomy has been performed since 1977 in patients with traumatic brain injury. The authors assess the efficacy of this treatment and the indications for its use. METHODS: The clinical status of the 57 patients, their computerized tomography (CT) scans, and intracranial pressure (ICP) levels were documented prospectively in a standard protocol. At the beginning of the study, all patients older than 30 years were excluded. As of 1989 patients older than 40 years were excluded until 1991; since that time patients older than 50 years have been excluded. Primary brain or brainstem injury with fully developed bulbar brain syndrome, loss of auditory evoked potentials (AEPs), and/or oscillation flow in a transcranial Doppler ultrasound examination were contraindications to decompressive craniectomy. A positive indication for decompression was given in the case of progressive therapy-resistant intracranial hypertension in correlation with clinical (Glasgow Coma Scale [GCS] score, decerebrate posturing, dilating of pupils) and electrophysiological (electroencephalography, somatosensory evoked potentials, and AEPs) parameters and with findings on CT scans. Unilateral decompressive craniectomy was performed in 31 patients and bilateral craniectomy in 26 patients. In all cases, a wide frontotemporoparietal craniectomy was followed by a dura enlargement covered with temporal muscle fascia. The outcomes of the treatment were surprisingly good. Only 11 patients (19%) died, three of whom died of acute respiratory disease syndrome. Five patients (9%) survived, but remained in a persistent vegetative state; six patients (11%) survived with a severe permanent neurological deficit, and 33 patients (58%) attained social rehabilitation. Two patients (3.5%) did not have a follow-up examination. The GCS score on the 1st day posttrauma and the mean ICP turned out to be the best predictors for a good prognosis. The results demonstrate the importance of decompressive craniectomy in the treatment of traumatic brain swelling. CONCLUSIONS: Surgical decompression should be routinely performed when indicated before irreversible ischemic brain damage occurs.

Adolescent↗
PubMed1998

Neuroendoscopic approach to intraventricular lesions.

OBJECT: The purpose of this study was to determine the efficacy of endoscopic treatment in patients with intraventricular tumors. METHODS: A series of 30 patients with endoscopically treated intraventricular lesions is reported. The lesions included seven colloid cysts, six astrocytomas, three subependymomas, two ependymomas, and one each of the following: pineoblastoma, pineocytoma/pineoblastoma (intermediate type), epidermoid cyst, pineal cyst, medulloblastoma, arteriovenous hemangioma, cavernoma, choroid plexus papilloma, pituitary adenoma, craniopharyngioma, melanoma, and germinoma. Total tumor resections, partial resections, biopsies, stent implantations, septostomies, and third ventriculostomies were performed. In two cases (two subependymomas > 2 cm in diameter), piecemeal endoscopic resection was ineffective because of the very firm consistency of the tumors. Therefore the endoscopic procedure was discontinued and the tumors were removed microsurgically. In the remaining cases the procedures were completed as planned. Even in the presence of difficulties such as poor orientation or significant bleeding, there was no need to abandon the endoscopic procedure. A total of 28 strictly endoscopic interventions were performed, in which the average duration was 85 minutes (range 35-170 minutes). All colloid cysts and the epidermoid lesion were completely evacuated and the capsules were widely resected. Total extirpation of solid tumors was achieved in five cases, whereas most astrocytomas were partially resected. The hydrocephalus-related symptoms resolved in all of the 22 patients with cerebrospinal fluid pathway obstruction. There were no endoscopy-related deaths. In two cases, major bleeding occurred and was controlled endoscopically. The authors observed one case of meningitis, one of mutism, two of memory loss attributed to forniceal injury, one of transient trochlear palsy after a biopsy specimen of an aqueductal tumor was obtained, and one of transient confusion after a biopsy specimen of a germinoma was obtained. CONCLUSIONS: In the authors' preliminary experience, the endoscopic approach was found to be safe and effective. In this series, it was possible to achieve relief of noncommunicating hydrocephalus, tumor resections, and even complete tumor removals by using endoscopic techniques. Based on the results, the authors believe that endoscopic techniques should be considered in the treatment of selected intraventricular lesions.

Adenoma↗
PubMed1998

Waterjet dissection of the brain: experimental and first clinical results. Technical note.

Control of bleeding during dissection is a problem that is still not completely resolved in neurosurgical procedures. To overcome this problem in some settings, the authors, in close collaboration with their institution, developed a new device for blunt dissection of brain tumors that is based on a waterjet technique. This report describes their first experimental and clinical experience with this new method. Numerous cutting experiments were performed in porcine cadaver brains. The best results were obtained using pressures from 4 to 6 bars with a 100-microm tip, which produced very small, precise cuts. Histological evaluation showed no disruption or vacuolization of the surrounding tissue. The authors have used the new device in nine patients (seven with gliomas and two undergoing temporal lobe resections for epilepsy), and no complications have been observed. The waterjet device allowed dissection of the brain tissue while even small exposed vessels were spared injury. The instrument was found to be easy to use. Future investigations will concentrate on adapting this new method to endoscopic surgery and evaluating fluids with low surface tension to avoid foaming and bubbling during open surgery.

Animals↗
PubMed1997

[Neuroendoscopy and endoscopic neurosurgery].

The trend in recent neurosurgery is going toward further reduction of invasiveness and avoidance of traumatization of the brain, spinal cord, and peripheral nerves to reduce the risk of neurological and mental deficit. In this way, the duration of hospital-stay and disablement can be shortened. An important "minimally invasive" technique is neuroendoscopy. The ventricular system and the subarachnoid space of the brain give suitable conditions for the use of an endoscope. Non-communicating hydrocephalus is the most frequent indication for an endoscopic approach. However, arachnoid cysts, cystic tumors, and intraventricular lesions may also effectively be treated with an endoscope. Using special instruments, laser devices, and bipolar diathermy, even highly vascularized lesions, such as cavernomas, may be completely resected. Moreover, endoscopes are used in the treatment of various spinal diseases and carpal tunnel syndrome, as well as in endoscopy-assisted microsurgery.

Brain Diseases↗
PubMed1997

Neurovascular compression at the left ventrolateral medulla as an etiological factor for arterial hypertension.

Clinical studies by Jannetta and others implicated that arterial compression of the root entry zone (REZ) of cranial nerves IX and X at the left ventrolateral medulla may represent an etiological factor for arterial hypertension. Positive therapeutic outcomes with reduction of hypertension in 42 of Jannetta's patients by microsurgical decompression initiated further studies. Experience of our group points in the same direction. Four patients treated by microvascular decompression showed lasting reduction of severe hypertension postoperatively. In our previous comparing postmortem explorations and angiographic studies essential hypertensive patients displayed signs of left sided neurovascular compression in opposition to normotone controls or renal hypertensive patients. By using MR-imaging we are currently developing a method of detecting neurovascular compression syndromes in hypertensive patients suitable for surgical management.

Autopsy↗
PubMed1997

Endoscopic observation of a slit-valve mechanism in a suprasellar prepontine arachnoid cyst: case report.

OBJECTIVE AND IMPORTANCE: There are several theories regarding the genesis of arachnoid cysts. However, controversy continues over what mechanisms are involved in the formation of the cysts. CLINICAL PRESENTATION: A 6-year-old female patient presented with precocious puberty. The results of a neurological examination were unremarkable. Magnetic resonance imaging revealed a large suprasellar prepontine arachnoid cyst. INTERVENTION: An endoscopic ventriculocystostomy via a right frontal burr hole was performed. During inspection of the cyst, we clearly observed a slit-valve mechanism that was obviously responsible for the formation and enlargement of the cyst. The valve was formed by an arachnoid membrane surrounding the basilar artery. Synchronous with pulsation, the valve opened and closed rapidly. CONCLUSION: A slit-valve mechanism seems to be at least one factor of the genesis of suprasellar prepontine arachnoid cysts.

Arachnoid↗
PubMed1997

Ictal and interictal ECD-SPECT for focus localization in epilepsy.

Forty-one ECD (Technetium-99m-ethyl cysteinate dimer) SPECT investigations were undertaken in the course of a presurgical diagnostic work-up in 23 patients with pharmacoresistant focal epilepsy. In 21 patients, both an ictal and interictal SPECT were conducted. In the patients receiving ictal SPECT the tracer was injected between 7 and 30 s after the seizure onset. Of the interictal SPECTs 17 of 23 showed focal hypoperfusion which was consistent in 17 cases (74%) with the area of the electrophysiological focus (EF) and 6 patients had a normal interictal SPECT. Of the ictal SPECTs 18 of 21 (86%) showed regional hyperperfusion, 18 of them in the same location as the EF. Ictal SPECT showed a hypoperfusion similar to that in interictal SPECT in another 3 patients. In these cases seizure duration was short (28-54 s), so that the tracer reached the brain postictally. Our results show that ictal ECD-SPECT is an effective method for demonstrating an epileptogenic focus. Possible reasons for false-negative ictal SPECT results are discussed.

Adolescent↗
PubMed1997

Infrared-based neuronavigation and cortical motor stimulation in the management of central-region tumors.

An infrared-based neuronavigation device (Surgical Microscope Navigator) integrating a pointer system with microscope guidance, is presented. We report our experience with this system in 17 patients undergoing surgery for space-occupying lesions of the central region. Cortical motor stimulation was additionally used in selected cases. The system was helpful in all operations by guiding craniotomy, corticotomy, or extent of tissue resection. Gross total tumor removal was possible in all patients but 1. Technical problems occurred in 1 case. Postoperative neurological worsening was found in 3 patients; this was reversible within a few weeks in 2 of them. In 9 cases, neuronavigation (combined with cortical stimulation, if necessary) probably prevented permanent neurological injury by exactly localizing tumors in the central area. It is concluded that neuronavigation (combined with motor cortex stimulation) may decrease neurological injury or neurosurgical invasiveness in lesions of the central region.

Astrocytoma↗
PubMed1996

Endoscopic treatment of an unusual multicystic lesion of the brainstem: case report.

We report a 32-year-old woman who presented with headache, mild hemiparesis and clumsiness of the right hand. CT and MRI revealed a multicystic formation of the brainstem involving the thalamus and midbrain. We inspected the formation endoscopically and fenestrated some of the cysts. In one of the cysts we found an anomalous vascular nidus. Postoperative MRI revealed reduction of the fenestrated cysts. The patient is doing well 13 months after endoscopy and has no neurological deficit.

Adult↗
PubMed1996

Neuroendoscopic approach to arachnoid cysts.

A prospective study of seven consecutive patients with congenital arachnoid cysts treated endoscopically is reported. The ages of the patients at the time of diagnosis ranged from 6 to 47 years with three patients under 15 years. Two cysts were located in the posterior cranial fossa, four in the middle cranial fossa, and one in the suprasellar-prepontine area. The patients' symptoms included headache, seizures, vomiting, nausea, dizziness, balance problems, and precocious puberty. The authors performed cystocisternostomies and ventriculocystostomies via burr holes with the aid of a universal neuroendoscopic system. Minor bleeding was easily controlled by rinsing. In one case, the endoscopic procedure had to be abandoned because of significant bleeding, which obscured a clear operative view, and an open microsurgical cyst fenestration was performed. The follow-up review periods in this group of patients ranged from 15 to 30 months. There was no mortality or morbidity. Symptoms were relieved in five patients and improved in one. Precocious puberty in one case continued. In six cases, follow-up magnetic resonance images or computerized tomography scans revealed a decrease in the size of the cysts. Although the follow-up period is too short to make statements on long-term outcome, the authors recommend the minimally invasive endoscopic approach for treatment of arachnoid cysts as the first therapy of choice. Should the endoscopic procedure fail, established treatment options such as microsurgical fenestration or cystoperitoneal shunting can subsequently be performed without causing additional risk to the patient.

Adolescent↗
PubMed1994

[Local oxygen supply to the cerebral cortex during thiopental and propofol anesthesia. First results].

Because the brain is highly vulnerable to damage from even a brief imbalance of oxygen delivery and demand, intraoperative disturbances of local oxygen supply must be avoided. Until now, there has been no method allowing fast and reliable intraoperative measurement of the local oxygen supply in the human brain. Intraoperative investigations were therefore performed using the Erlangen micro-lightguide spectrophotometer. METHODS. Intraoperative investigations of local intracapillary haemoglobin saturation (SO2) were performed during neurosurgical interventions using the Erlangen microlightguide spectrophotometer (EM-PHO). Measurements were performed in eight patients (age 31-67 years) during neurosurgical interventions. Three received thiopentone anaesthesia, and three received propofol. In two patients thiopentone anaesthesia was later changed to propofol. The EMPHO enables rapid, non-invasive measurement of local intracapillary SO2. White light from a Xenon-arc lamp is transmitted by a 250-microns micro-lightguide to the tissue. The remitted (reflected) light is led by 6 micro-lightguides surrounding the illuminating one to a rotating band-pass interference filter disk. Light in the range of 502 to 630 nm is detected with a photomultiplier. In this range haemoglobin shows an SO2-dependent spectrum, which is then analysed. Because the measurements are performed with micro-lightguides, high spatial resolution is attained. Representative measurements can be performed in a very short period of time (approx. 60 s); thus, the EM-PHO enables rapid monitoring of local SO2 in the brain. RESULTS. The effect of propofol and thiopentone anaesthesia on the distribution of local intracapillary haemoglobin saturation was investigated during neurosurgical interventions. The arterial PCO2 was similar in both groups (31 +/- 0.7 and 31 +/- 0.5 mmHg, respectively). There were also no differences in arterial blood pressure. The FiO2 was 0.28 +/- 0.04 in the thiopentone group and 0.30 +/- 0.1 in the propofol group. In all patients receiving propofol anaesthesia higher local SO2 values were found, even if the patients first received thiopentone (values in parenthesis). The mean local SO2 amounted to 65.4% (57.3%) in the propofol group and 38.8% (45.2%) in the thiopentone group. The number of values below 25% SO2 was 5.6% (5.8%) in the propofol group and 18.7% (19.1%) in the thiopentone group.

Adult↗
PubMed1994

Effect of arterial PCO2 on local HbO2 and relative Hb concentration in the human brain--a study with the Erlangen micro-lightguide spectrophotometer (EMPHO).

Intraoperative investigations of local intracapillary haemoglobin oxygenation have been performed in 5 patients during neurosurgical interventions using the Erlangen microlightguide spectrophotometer (EMPHO). As the measurements can be performed in a very short period of time (approximately 60 s) the EMPHO enables rapid monitoring of local haemoglobin oxygenation in the brain. All patients received thiopental anaesthesia and were mechanically ventilated. The local measurements were performed during normoventilation (arterial PCO2--PaCO2 37.8 +/- 0.7 mm Hg) and hyperventilation (PaCO2 31 +/- 0.5 mm Hg). Hyperventilation caused a decrease in the mean SO2 from 47.8% to 41.1%. The number of SO2 values < 50% increased from 58% to 77.8%. The possible significance of the low local SO2 values is discussed.

Adult↗
PubMed1994

"Ultrahigh" dexamethasone in acute brain injury. Results from a prospective randomized double-blind multicenter trial (GUDHIS). German Ultrahigh Dexamethasone Head Injury Study Group.

In a prospective randomized double-blind multicenter trial, the efficacy and safety of a 51-hour ultra-high intravenous dexamethasone dosing regimen was investigated in patients with moderate and severe head injury. 300 patients between 15 and 55 years of age were randomized to receive either placebo or dexamethasone: 500 mg intravenous infusion within 3 h after trauma initially, followed by 200 mg after 3 h, thereafter 8 times 200 mg at 6 hourly intervals, resulting in a total administered dose of 2,3 g in 51 hours. Primary end points for assessment of efficacy were: Modified Glasgow Coma Scale (grading 3-16) on Day 5, modified Glasgow Outcome Scale (grading 1-6) 10-14 months after injury, and the time interval until consciousness improved above a level of modified GCS > or = 8. Secondary endpoints were CT results and neurological and laboratory data. The two groups were well matched with respect to important prognostic variables, such as age, severity of trauma, and interval between trauma and application of the drug. 269 patients (89.7%) were available for final examination after 10-14 months. Results were surprisingly favourable in both groups: Lethality in the dexamethasone and placebo group was 14.3 and 15.4%, respectively, and 61.7 and 57.4%, respectively, achieved social and professional rehabilitation after 10-14 months (outcome scale 6). No statistical difference was seen between the dexamethasone and the placebo group in any of the primary end points of efficacy and safety (incidence of upper gastrointestinal bleeding, infection, and thrombosis).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗