[Deep brain stimulation in the posterior hypothalamus for chronic cluster headache. Case report and review of the literature]

Primary chronic cluster headache (CCH) is a rare but severe pain syndrome and pathophysiological explanations are still missing. PET studies revealed activation in the hypothalamus and therefore it became a target for therapeutic deep brain stimulation (DBS). A case of a 39-year-old woman and a literature review are presented. The patient suffered from left-sided primary CCH for 14 months. The headache was resistant to any pharmacological therapy or treatment was limited by major drug side effects. Using a stereotactic approach a quadripolar lead was inserted in the left posterior hypothalamus. A test trial was performed and attack frequency, intensity, and adverse events were noted. Intraoperative test stimulation evoked typical side effects like tachycardia, diplopia and panic attacks. During the trial test a marked reduction in frequency and intensity of CCH was recorded. After 7 days the stimulation device was implanted subcutaneously. DBS with implantation of a lead in the ipsilateral inferior posterior hypothalamus is an experimental treatment option and should be offered to selected patients in a prospective controlled clinical trial. Data concerning the long-term follow-up need to be collected.

[Brachytherapy in combination with function-preserving surgery. An interdisciplinary challenge]

A multimodal, interdisciplinary approach known as intensity-modified brachytherapy is a promising alternative for patients with advanced head and neck cancer infiltrating the orbita and skull base. An 87-year-old man presented with a recurrence of squamous cell carcinoma of the medial corner of the left eye that had been locally resected and irradiated by external beam radiotherapy multiple times. The cancer was resected with preservation of the eye with close margins, implantation of afterloading catheters, and reconstruction of the defect with a median forehead flap. The patient was irradiated with a total radiation dose of 30 Gy IMBT. After 1 year, there was no evidence of locoregional recurrence. The background of this therapeutic process and analysis of the current literature regarding this interdisciplinary treatment of head and neck cancer infiltrating the orbita and skull base are discussed based on this case report.

Interstitial glycerol increase in microdialysis after glycerol enema

Microdialysis allows the measurement of extracellular concentrations of various endogenous substances, such as excitotoxic amino acids or metabolic end products. Recent advances in microdialysis techniques have led to widespread use in patients with brain disorders. Microdialysis has proved to be a useful tool for monitoring cerebral biochemical metabolism and secondary brain damage in severe head injury, subarachnoid haemorrhage, stroke, and epilepsy. In our neurosurgical intensive care unit, microdialysis was performed on 42 patients. Four patients received a glycerol enema for therapy of a paralytic ileus. A glycerol peak was observed in both intracerebral and subcutaneous microdialysis occurring three to four hours after the glycerol enema in all four patients. The highest glycerol value was 1187micromol/l cerebral and 2997micromol/l in the subcutaneous tissue. Our study indicates that besides the measurement of serum osmolality and serum glycerol level, microdialysis may be an additional valuable tool to control glycerol therapy in patients with cerebral oedema and elevated intracranial pressure.

Outcome Prediction of Third Ventriculostomy: A Proposed Hydrocephalus Grading System

An important factor in making a recommendation for different treatment modalities in hydrocephalus patients (VP shunt versus endoscopic third ventriculostomy) is the definition of the underlying pathology which determines the prognosis/outcome of the surgical procedure. Third ventriculostomies (3rd VS) are successful mainly in obstructive hydrocephalus but also in some subtypes of communicating hydrocephalus. A simple, easily applicable grading system that is designed to predict the outcome of 3rd VS is proposed. The hydrocephalus is graded on the basis of the extent of downward bulging of the floor of the third ventricle, which reflects the pressure gradient between the 3rd ventricle and the basal cisterns, presence of directly visualised CSF pathway obstruction in MRI, and the progression of the clinical symptoms resulting in five different grades. In this proposed grading system, grade 1 hydrocephalus subtype shows no downward bulged floor of the 3rd ventricle, no obstruction of the CSF pathway, and no progressive symptoms of hydrocephalus. There is no indication for 3rd VS. Grades 2 to 4 show different combinations of the described parameters. Grade 5 subtype shows a markedly downward bulged floor of the 3rd ventricle and direct detection of the CSF pathway obstruction (i.e., aqueductal stenosis) with progressive clinical deterioration. Retrospective application of this grading scheme to a series of 72 3rd VS has demonstrated a high correlation with the outcome: The success rate in grade 3 reached 40%, in grade 4: 58%, and in grade 5: 95%. This standardised grading system predicts the outcome of 3rd VS and helps in decision making for 3rd VS versus VP shunting.

Frontoethmoidal encephalocele with ocular leakage of cerebrospinal fluid. Case report

The authors present the case of a 2-year-old boy who was born with a small bulging mass in the middle frontonasal area and hypertelorism. In the neonatal period he suffered from a continuous lacrimal secretion mistaken for recurrent conjunctivitis. Cranial computerized tomography scanning and magnetic resonance imaging revealed a frontoethmoidal encephalocele associated with an ocular leakage of cerebrospinal fluid. One-stage repair of the encephalocele, along with correction of hypertelorism and bone grafting of the forehead, was performed with good result. During a 2-year follow-up period no neurological deficits appeared.

Hydrocephalus therapy: reduction of shunt occlusions using a peel-away sheath

In order to avoid shunt occlusions through particles of brain parenchyma a new procedure was used. Conventionally during ventricle puncture brain tissue may intrude into perforating holes of the ventricular catheter and subsequently shunt dysfunction may occur. By using a peel-away sheath the ventricular catheter can be protected during puncture. The conventional technique (n=90) was compared with the peel-away sheath technique (n=20) in a retrospective analyses in regard to shunt revisions during a 1-year period. Shunt revision was done in 18% (16/90) within 1 year using the conventional technique, respectively, 5% (1/20) using the peel-away sheath technique. Although criteria for statistical significance were not reached these data are worth to be mentioned. A randomised prospective study is initiated and the key features are presented.

Cerebral haemodynamic pathologies in HELLP syndrome

The syndrome of haemolysis, elevated liver enzymes and low platelets (HELLP syndrome) is understood as a unique variant of severe preeclampsia. This disorder complicates between 2 and 7% of gestations and is associated with a high perinatal morbidity and a maternal morbidity ranging between 1 and 4%. Intracerebral complications only rarely occur, especially intracerebral haemorrhage was described only in single cases, often correlated with fatal maternal outcome. The analysis of patients with HELLP syndrome treated at our hospital revealed three cases with severe neurological deterioration. Possible pathogenetic factors are discussed.

The Mechanism of Fornix Lesions in 3rdVentriculostomy

Fornix lesions as a complication of 3rd ventriculostomy are rare and almost not reported. However, in our series of 94 procedures we observed 5 fornix lesions. Although we did not find any clinical deterioration, we were alarmed by these unexpected incidences and analysed the mechanism. All fornix lesions occurred using an endoscope sheath with separated channels for the endoscope itself, the instruments and for rinsing and suction. The limited field of view suggests the surgeon to be already inside the 3rd ventricle while the tip of the scope is still in the lateral ventricle just before the foramen of Monro. The instrument enters the optic field--depending on the used optic--as lately as 2 to 3 mm. The analysis showed that the lesions happened when the instruments were in the blind angle of the endoscope's optic which itself was outside of the foramen of Monro. Being aware of this mechanism with its potential risks it did not occurred again.

Pro and Cons of Different Designs of Rigid Endoscopes

Experience with more than 200 neuroendoscopic procedures taught us the advantages and disadvantages of the different endoscope designs. Using an endoscope with a sheath with separate channels for the endoscope, the instruments as well as for rinsing and suction we found advantages in rinsing properties, handling, and preciseness of instrument steering. On the other hand an endoscope with a sheath with a singular channel for the endoscope itself, the instruments, rinsing, and suction the advantages were better in visualization of the instruments, more available instruments, and easier extraction of larger specimen. The knowledge of these advantages makes it possible to select the adequate endoscope regarding its design, especially in more complicated cases.

Proliferation, migration, and invasion of human glioma cells exposed to fractionated radiotherapy in vitro

Radiotherapy is a well established treatment for malignant gliomas. This study describes the migration, proliferation, and invasion behaviour of two human glioma cell lines (GaMg and U-87 Mg) grown as multicellular tumour spheroids after radiotherapy. Migration and proliferation studies were performed using conventional and accelerated fractionation up to 60 Gy and 59.4 Gy, respectively. A dose-dependent growth and migratory response to irradiation independent of the type of fractionation was observed. A coculture system in which tumour spheroids were confronted with foetal rat brain aggregates was used for invasion studies. Marked invasion of the glioma spheroids into the brain aggregates occurred with or without radiotherapy. For the GaMg cells, flow cytometric DNA histograms after treatment with 10 Gy and 40 Gy showed an accumulation of cells in the G2/M phase of the cell cycle. Radiotherapy inhibits tumour cell growth and migration, but the invasiveness of the remaining tumour cells seems to be unaffected.

Tissue metabolism during endotoxin shock after pretreatment with monophosphoryl lipid A

OBJECTIVE

Preconditioning pigs with low doses of monophosphoryl lipid A (MPL), a non toxic derivate of lipid A, has been shown to induce endotoxin hyporesponsiveness and to reduce the metabolic and hemodynamic consequences of endotoxin shock. However, the mechanism is presently unclear. This study was designed to elucidate the effects of pretreatment with MPL on tissue metabolism in different organs by in vivo microdialysis of interstitial fluid.

METHODS

In a controlled animal study at the university research laboratory, seven female mixed-breed pigs were exposed to an endotoxin infusion (1 microg/kg b.w. per h) after pretreatment with MPL in incremental doses of endotoxin during days 5-2 before the experiments. Seven animals receiving a saline pretreatment served as a control group. Hemodynamic variables and blood gas analyses including blood lactate were determined every 30 min until the animals died. Interstitial lactate and glycerol levels were measured in muscle, subcutaneous tissue and liver using in vivo microdialysis.

RESULTS

Survival time was significantly prolonged after MPL preconditioning (8.95 (7.5-9.1) h vs. 5.35 (5.0-5.6) h, P<0.05). Hemodynamic parameters were not significantly different between the treatment and control groups, while mixed venous saturation (81% (70-93%) vs. 30% (22-48%)) and arterial blood pH (7.39 (7.33-7.44) vs. 7.21 (7.1-7.25)) and pO(2) were significantly higher in the preconditioned group (P<0.05). The interstitial concentrations of lactate and glycerol in all investigated tissues were significantly higher in control animals than the those who had been pretreated with MPL (P<0.05).

CONCLUSIONS

Preconditioning with low doses of monosphosphoryl lipid A attenuates the negative effects of endotoxemia on tissue metabolism, probably by reducing O(2)-consumption. These changes may be subtle and, hence, only fully detectable by monitoring tissue metabolism.

Atypical delayed intracranial haematoma following stereotactic biopsy of a right parietal anaplastic oligodendroglioma

The history of a 73-year-old woman with an anaplastic oligodendroglioma is presented, in whom cerebral magnetic resonance imaging (MRI) and brain single-photon emission tomography (SPECT) revealed an intracerebral lesion 17 months before, which was misinterpreted as cerebral infarction. Stereotactic biopsy confirmed the diagnosis, but 4 days after biopsy an unexpected fatal subdural and intraparenchymal bleeding occurred on the biopsy site. Neuroradiological aspects in the differential diagnosis of cerebral lesions as well as the role of small silent postbiopsy haematoma concerning further clinical deterioration are discussed.

Clinical biochemical tissue monitoring during ischaemia and reperfusion in major vascular surgery

BACKGROUND

Major vascular surgery with aortic cross-clamping is associated with temporary ischaemia of the lower limb due to lack of tissue blood flow. The present study was designed to determine if the short-term changes in cellular metabolism occurring during this situation can be detected by subcutaneous microdialysis. It was also hoped to ascertain if this new technique is useful in the continuous bedside monitoring of metabolism during aortic surgery.

METHODS

In a controlled clinical study 20 patients undergoing elective aortic surgery were monitored using microdialysis probes that were inserted in the subcutaneous tissue of the left lower limb and a non-ischaemic region (shoulder). Interstitial fluid was obtained and the concentrations of glucose and lactate during lower limb ischaemia and during reperfusion were measured and compared with concentrations observed in fluid obtained from the non-ischaemic control tissue.

RESULTS

Circulatory occlusion caused an immediate and significant decrease in the glucose/lactate ratio from 3.1+/-1.3 to 0.48+/-0.5 (P<0.05) that returned to preocclusion values within 2 h of commencing reperfusion.

CONCLUSION

We suggest that microdialysis may be used both to assess acute changes in tissue metabolism during ischaemic periods and also to act as an additional tool for the detection of peri-operative acute variations in limb blood flow.

Migration, proliferation, and invasion of human glioma cells following treatment with simvastatin

This study describes the migration, proliferation, and invasion behaviour of two human glioma cell lines, GaMg and U-87 Mg, grown as multicellular tumour spheroids after 3-hydroxy-3-methylglutaryl coenzyme A (HMGCoA) reductase inhibitor (simvastatin) therapy. Migration and proliferation studies were performed using simvastatin in concentrations of 0.2-30 microg/ml(-1). A coculture system in which tumour spheroids were confronted with foetal rat brain aggregates was used for invasion studies. A dose-dependent growth and migratory inhibitory response to simvastatin treatment was observed. Marked invasion of the glioma spheroids into the brain aggregates could be seen in both treated and nontreated groups. Simvastatin therapy inhibits tumour cell growth and migration, but the invasiveness of the remaining tumour cells seems to be unaffected.

Neuroradiological findings in primary cerebral lymphomas of non-AIDS patients

Primary central nervous system lymphomas (PCNSL's) are rare tumours which generally accounted for 1.0-1.5% of all intracranial neoplasms. However, within the last decade the frequency of cerebral lymphomas has dramatically increased. We retrospectively analysed the neuroradiological findings (computed tomography (CT), MRI, angiography) in 37 patients with PCNSL. Thirty patients with the clinically and neuroradiologically suspected diagnosis of cerebral lymphoma underwent CT- or MRI-guided stereotactic biopsy. In seven cases an open surgical intervention was performed. Preoperatively, CT with and without contrast medium was performed in all but two cases. Twenty-eight patients received MRI (axial SE T2 weighted, triplanar SE T1 weighted, triplanar SE T1+Gadolinium). Additionally, in 9 patients cerebral angiography was performed. Typical neuroradiological patterns are: (1) iso- or hyper-density (85.5%) on unenhanced CT scan with marked contrast enhancement (87.7%); (2) infiltration/contact of leptomeningeal and/or ependymal spaces (97.3%); (3) hyperintensity on T2 with moderate oedema (80.3%). Histopathological work-up included conventional and immunohistochemical stains performed on formalin fixed and paraffin embedded bioptical specimen. Despite widely used preoperative dexamethasone treatment, an accurate histopathological diagnosis of PCNSL of B cell type was established in all cases except one. The high percentage of accurate histopathological diagnosis was based on: (1) great mean sample volume per biopsy site; (2) great number of biopsies in patients suspected to have cerebral lymphomas; and (3) MR-guided stereotactic procedures if the lesion was not clearly identifiable on CT scan.

Biochemical tissue monitoring during hypoxia and reoxygenation

Oxygen deficiency during critical illness may cause profound changes in cellular metabolism and subsequent tissue and organ dysfunction. Clinical treatment in these cases targets rapid reoxygenation to avoid a prolonged impaired synthesis of cellular high-energy phosphates (ATP). However, the effect of this therapeutic intervention on tissue metabolism has not been determined yet. Thus the present study was designed to determine the effects of hypoxia and reoxygenation with either room air or 100% oxygen on variables of interstitial metabolism in different tissues using in vivo microdialysis. Twenty-seven adult, male CD-rats (407-487 g; Ivanovas, Kisslegg, Germany) were studied during general anesthesia. Following preparation and randomization, rats were normoventilated for 45 min (FiO(2) 0.21), followed by induction of hypoxia (FiO(2) 0.1, 40 min) and reoxygenated for 50 min either with FiO(2) 1.0 (group 1, n=10) or FiO(2) 0.21 (group 2, n=10). Control animals (n=7) were ventilated with 21% oxygen during the observation period. Additional to invasive haemodynamic parameters, biochemical tissue monitoring was performed using CMA 20 microdialysis probes, inserted into muscle, subcutaneous space, liver, and the peritoneal cavity allowing analyses of lactate and pyruvate at short intervals. Hypoxia induced a significant reduction in mean arterial pressure (MAP) in group 1 and 2 compared with the control group (P<0.05) without any significant differences between both treatment groups. This was accompanied by a significant increase in blood lactate (10.5+/-3.1 mM (group 1) and 12.3+/-4.1 mM (group 2) vs. 1.5+/-0.3 mM (control); P<0.05) and severe metabolic acidosis (base excess (BE): -18.3+/-5 mM (1) and -17.3+/-7 mM (2) vs. -2.6+/-1.8 mM (control), P<0.05). During hypoxia, the interstitial lacate/pyruvate ratio in groups 1 and 2 increased to 455+/-199% (muscle), 468+/-148% (intraperitoneal), 770+/-218% (hepatic) and 855+/-432% (subcutaneous) (P<0.05 vs. control, respectively). No significant inter-organ or inter-group differences in interstitial dialysates were observed in the treatment groups, neither during hypoxia nor during reoxygenation. Our data suggest, that hypoxia induces comparable metabolic alterations in various tissues and that reoxygenation with 100% oxygen is not superior to 21% oxygen in restoring tissue metabolism after critical hypoxia.

Extraventricular intracisternal obstructive hydrocephalus--a hypothesis to explain successful 3rd ventriculostomy in communicating hydrocephalus

The basis of successful 3rd ventriculostomy in cases of communicating hydrocephalus is not yet understood. We performed 3rd ventriculostomies in 5 patients with free cerebrospinal fluid (CSF) communication from the ventricles to the cisterna magna. Preoperative magnetic resonance images (MRIs) showed dilated ventricles, a downward bulging floor of the 3rd ventricle (interpreted as a sign of pressure gradient between the ventricles and basal cisterns) and a free communication to an enlarged cisterna magna. The other basal cisterns were of normal or smaller size. All patients recovered from their clinical symptoms and none of them needed a shunt. The hypothesis of an intracisternal CSF pathway obstruction (e.g. between the cisterna magna and the prepontine cistern) could explain the MRI findings, although such an obstruction cannot be directly visualized. It would also explain the successful 3rd ventriculostomies in these cases.

[Continuous biochemical tissue monitoring during acute hypoxia]

Oxygen deficiency during critical illness is known to cause profound changes in cellular metabolism with subsequent organ dysfunction. Clinical treatment in these patients is focussed on rapid reoxygenation to avoid a prolonged impaired synthesis of cellular high-energy phosphates (ATP). The effect of this therapeutical intervention on the level of the cell, however, has not yet been objectivized. The aim of the present experimental study was to biochemically monitor different tissues during hypoxia and reoxygenation using in vivo microdialysis. Eighteen adult male CD-rats (412-469 g; Ivanovas, Kisslegg, Germany) were normoventilated under general anaesthesia (FiO2 = 0.21). Ten were then subjected to a period of hypoxia (FiO2 = 0.1, 40 min) and reoxygenated with FiO2 = 0.21, while eight control animals were continuously ventilated with FiO2 = 0.21. In addition to invasive haemodynamic monitoring, biochemical tissue monitoring was performed using CMA 20 microdialysis probes, which were inserted into the muscle (m), subcutaneous space (s), liver (l) and peritoneal cave (p) with semicontinuous analyses of lactate and pyruvate at intervals of 15 minutes. Hypoxia induced a significant decrease in mean arterial pressure compared to the control group (p < 0.05). At the same time significant increases in blood lactate (12.3 + 4.1 mmol/l (hypoxia) vs. 1.5 +/- 0.3 mmol/l (control); p < 0.05) and in negative base excess (17.3 + 7 mmol/l (hypoxia) vs. 2.6 + 1.8 mmol/l (control), p < 0.05) occurred. Compared to unchanged levels in the control animals, the interstitital lacate/pyruvate ratio in the investigation group rose to significantly higher values (455 + 199% of baseline (m), 468 + 148% (p), 770 + 218% (l) and 855 + 432% (s) (p < 0.05). An immediate return to the baseline values after the start of reoxygenation was noted in the L/P ratio during the observation period. Using microdialysis, it was possible to objectify the effect of oxygen deficiency and restoration on tissue metabolism. Regarding clinical and preclinical practice, microdialysis monitoring should be performed to include biochemical cellular effects as an additional target for therapeutical interventions.

Long-time microdialysis in a patient with meningoencephalitis

As part of invasive neuromonitoring, long-time microdialysis was performed in a 32-year-old patient suffering from meningoencephalitis. Cerebral magnetic resonance imaging (MRI) revealed marked global brain oedema. An intracranial pressure (ICP) probe, brain tissue oxygen pressure measurement (pTiO(2)), and intraparenchymal microdialysis were used for intensive neuromonitoring. Despite high ICP, only intensive care therapy was applied for 16 days using deep propofol sedation, hyperventilation, and intermittent mannitol therapy. One year later, the condition of the patient was excellent. Intracerebral microdialysis with bedside measuring of lactate, pyruvate, glycerol, glucose, and glutamate is a useful additional tool for the monitoring of ICP management.

Intraperitoneal microdialysis for detection of splanchnic metabolic disorders

BACKGROUND AND AIMS

Due to its high oxygen demand the gastrointestinal tract is very susceptible to hypoxia or ischemia, which may result in local and systemic dysfunction. Early detection of any profound disorders (e.g., after abdominal surgery) remains an important target for the surgeon. This study investigates whether in vivo microdialysis monitoring of the intraperitoneal space adequately reflects hypoxic conditions.

METHODS

Hypoxic hypoxia by ventilation was induced in 14 rats under general anesthesia with FIO(2) of 0.1 (40 min) followed by reoxygenation with FIO(2) of 0.21. Hemodynamic and blood gas monitoring including blood lactate was performed. Microdialysis catheters were placed in the peritoneal cavity, and lactate, pyruvate, and glycerol were measured out of the ascites.

RESULTS

A significant decrease in mean arterial pressure and increase in blood lactate level during the hypoxic period was observed. Hypoxia induced an immediate and significant elevation in the intraperitoneal lactate/pyruvate ratio to 446+/-137% of the baseline values, and glycerol subsequently increased during reoxygenation to 389+/-109%. Values for the blood compartment showed less profound or no significant differences.

CONCLUSIONS

Biochemical monitoring of the intraperitoneal space by in vivo microdialysis, such as after laparatomy can measure metabolic changes in the gastrointestinal tract produced by hypoxia/ischemia. The surgeon may thus detect postoperative complications at an earlier stage than with routine monitoring devices.

A simple method of reapplying the Leksell stereotactic frame without any repetition of the CT scan

A simple method to reapply the Leksell stereotactic frame using marked carbon pins is described. This method allows the reapplication in a quick and safe manner without repetition of the CT scan. The reproducibility was very high.