Calvarial lesions: overview of imaging features and neurosurgical management.

Calvarial lesions are rare and can present as a variety of different diseases. The lesions can be palpable on the skin and cause local pain and paraesthesia and, depending on the location, neurological deficits can also occur. This research aims to present an overview of typical imaging features as well as neurosurgical management. We examined the charts of patients who underwent surgery on a calvarial lesion in our department between 2004 and 2017 (n=133). Retrospectively, the pre-, intra-, and postoperative data were analyzed with morphological and histological findings and compared with each other. Pain, swelling, cosmetically disturbing, and neurological deficits were the main complaints. Seventy-seven lesions were limited to the bone, while another 56 lesions showed an infiltrating growth in the adjacent tissue. Depending on the clinical signs and suspected diagnosis, a biopsy, a partial removal, or a complete resection was performed. Histiocytosis (n=20), meningiomas (n=20), metastases (n=19), and osteomas (n=16) were the most common lesions. Fibrous dysplasia (n=6) and intraosseous hemangioma (n=9) were less common; other lesions were present only in isolated cases. Imaging features may suggest the lesion to be benign or malignant, but the diagnosis can be only confirmed by histological examination. The surgical strategy depends on the complaints, location of the lesion, and suspected diagnosis. Adjuvant treatment should be initiated according to the histological findings.

Relationship of the vascular territory affected by delayed cerebral ischemia and the location of the ruptured aneurysm in patients with aneurysmal subarachnoid hemorrhage.

OBJECTIVE: To determine the area most at risk of delayed cerebral ischemia (DCI) in relation to the location of the ruptured aneurysm in patients with aneurysmal subarachnoid hemorrhage (aSAH) and, therefore, help to choose the site for focal multimodal neuromonitoring. METHODS: We retrospectively analyzed angiographic findings, CCT scans, and patient charts of patients who were admitted with aSAH to our neurosurgical intensive care unit between 2009 and 2017. DCI was defined as infarction on CCT 2-6 weeks after aSAH. RESULTS: DCI occurred in 17.9% out of 357 included patients. A DCI occurring in the vascular territory of the artery carrying the ruptured aneurysm was found in 81.0% of patients with anterior circulation aneurysms but only in 16.7% with posterior circulation aneurysms (Fisher's exact, p=0.003). The vascular territory most frequently showing a DCI was the ipsilateral MCA territory (86.7%) in ICA aneurysms, the contra- (71.4%) and the ipsilateral (64.3%) ACA territory in ACA aneurysms, the right (93.8%) and the left (81.3%) ACA territory in AcomA aneurysms, and the ipsilateral MCA territory in MCA aneurysms (69.2%) as well as in VA/PICA/SCA aneurysms (100.0%). DCI after the rupture of a BA aneurysm occurred with 33.3% in 6 out of 8 vascular territories, respectively. DCI of multiple vascular territories occurred in 100.0% of BA aneurysms, 87.5% of AcomA aneurysms, 71.4% of ACA aneurysms, 40.0% of ICA aneurysms, 38.5% of MCA aneurysms, and 33.3% of VA/PICA/SCA aneurysms. DISCUSSION: Few studies exist that could determine the area most at risk of a DCI after an aSAH. Our data could identify the territory most at risk for DCI with a probability of > 60% except for BA aneurysms, which showed DCI in various areas and patients suffering from multiple DCIs. Either the ipsilateral ACA or MCA were affected by the DCI in about 80% of ACA and more than 90% of AcomA, ICA, MCA, and VA/PICA/SCA aneurysms. Therefore, local intraparenchymal neuromonitoring in the ACA/MCA watershed area might detect the vast majority of DCIs for all aneurysm locations, except for BA aneurysms. In ACA and AcomA aneurysms, bilateral DCI of the ACA territory was common, and bilateral probe positioning might be considered for monitoring high-risk patients. Non-focal monitoring methods might be preferably used after BA aneurysm rupture.

COX2 expression is associated with proliferation and tumor extension in vestibular schwannoma but is not influenced by acetylsalicylic acid intake.

Acetylsalicylic acid has been linked to a lower risk for different cancer types, presumably through its inhibitory effect on cyclooxygenase 2. This has also been investigated in vestibular schwannomas with promising results suggesting an antiproliferative effect and recently the intake has been recommended for vestibular schwannomas as a conservative treatment option. We constructed tissue microarrays from paraffin-embedded tissue samples of 1048 vestibular schwannomas and analyzed the expression of cyclooxygenase 2 and the proliferation marker MIB1 (Molecular Immunology Borstel) via immunohistochemistry together with clinical data (age, gender, tumor extension, prior radiotherapy, neurofibromatosis type 2, tumor recurrence, cyclooxygenase 2 responsive medication). Univariate analysis showed that cyclooxygenase 2 expression was increased with age, female gender, prior radiotherapy and larger tumor extension. MIB1 expression was also associated with higher cyclooxygenase 2 expression. Schwannomas of neurofibromatosis type 2 patients had lower cyclooxygenase 2 levels. Use of acetylsalicylic acid, non-steroidal anti-inflammatory drugs, glucocorticoids or other immunosuppressants did not show differences in cyclooxygenase 2 or MIB1 expression. Instead, cyclooxygenase 2 expression increases with tumor extension while MIB1 expression is not associated with tumor size. Overall, cyclooxygenase 2 expression is associated with proliferation but not influenced by regular intake of acetylsalicylic acid or other cyclooxygenase 2-responsive medications. Acetylsalicylic acid intake does not alter cyclooxygenase 2 expression and has no antiproliferative effect in vestibular.

Microvascular decompression for treating classical trigeminal neuralgia: can we offer the gold standard therapy to older patients?

PURPOSE: Microvascular decompression is the most successful procedure for treating classic trigeminal neuralgia. However, due to the risks of surgery and anesthesia, the procedure is performed less frequently in older patients. The aim of the study is to investigate the intraoperative and perioperative morbidity in older patients who underwent this surgical treatment. METHODS: Patients who underwent microvascular decompression in our department between 2004 and 2016 were divided into two age groups (A: < 69 years old, n = 114; B: ≥ 70 years old, n = 47). Retrospectively, the pre-, intra- and postoperative data were analyzed. RESULTS: Older patients showed a statistically significant prolonged duration of symptoms until surgery (mean 127 months vs. 70 months; p < 0.001). They also showed a significantly increased necessity for duroplasty (p = 0.015), but with no increased incidence of postoperative cerebrospinal fluid leakage or rhinoliquorrhea. A comparable postoperative course was found in both groups. Over 90% in both groups had a significantly postoperative improvement. There were no cardiopulmonary complications or infections in either group. In the 3-month follow-up, there was a comparable success of pain reduction and no increased incidence of sensory disturbances. CONCLUSIONS: Based on the high chances of success and low morbidity, microvascular decompression should also be offered to older patients with anesthesiologic agreement.

Estimation of Severity of Moyamoya Disease with [15O]Water-Positron Emission Tomography Compared with Magnetic Resonance Imaging and Angiography.

BACKGROUND: Moyamoya disease is a steno-occlusive disease of the circle of Willis with growth of pathologic collaterals. We compared functional perfusion imaging ([15O]water-positron emission tomography [PET] with acetazolamide challenge) with conventional magnetic resonance imaging (MRI) and angiography for determining indication for cerebral revascularization in patients with moyamoya. METHODS: We performed a retrospective blinded analysis of individual imaging modalities (MRI, angiography, PET) and scored each modality for severity of disease in 21 untreated patients with moyamoya with 78 affected vascular territories. RESULTS: Positive predictive value to identify insufficient perfusion on angiography and MRI together was 98.3% as proven on combined PET/computed tomography. Negative predictive value to identify sufficient perfusion on angiography and/or MRI only was 60%. Negative predictive value to predict good perfusion on PET based on MRI (no infarctions in the respective territory) was only 17%. An assumed good perfusion based on the suggestion of good collaterals on angiography was correct in only 13.4% of cases. Positive predictive value (angiography of main vessel and weak or no collateralization) to predict insufficient perfusion on PET/computed tomography was 76.9%; negative predictive value (angiography of main vessel and strong collateralization) to identify good perfusion was 13.4%. CONCLUSIONS: Reliable evaluation of cerebral blood flow might not be possible with angiography and basic MRI alone. We strongly recommend additional functional imaging (e.g., [15O]water-PET with acetazolamide challenge) to precisely evaluate the indication for cerebral revascularization.

The possibility of seeding vestibular schwannomas through surgery: Limited experience with two cases.

BACKGROUND: We present two exceptional cases of possible tumor seeding in benign vestibular schwannoma (VS) patients occurring years after initial microsurgical resection. CASE DESCRIPTION: We retrospectively analyzed the surgical management, histology and documented the growth of new tumor occurrence in close vicinity of the original schwannomas by serial magnetic resonance imaging over a period of 10 years. None of the patients had stigmata of neurofibromatosis, making it a reasonable assumption that the second tumor was due to surgical seeding during the first surgery. Moreover, in the second case, a microsurgical re-exploration showed that the recurrent tumor did not show any adhesion or contact to the caudal cranial nerves as anticipated had this been a new cranial nerve schwannoma. CONCLUSIONS: Surgical seeding of VSs is a rare complication but can occur despite benign histology and generous irrigation during surgery.

Fronto-temporal branch of facial nerve within the interfascial fat pad: is the interfascial dissection really safe?

BACKGROUND: The study was conducted to clarify the presence or absence of fronto-temporal branches (FTB) of the facial nerve within the interfascial (between the superficial and deep leaflet of the temporalis fascia) fat pad. METHODS: Eight formalin-fixed cadaveric heads (16 sides) were used in the study. The course of the facial nerve and the FTB was dissected in its individual tissue planes and followed from the stylomastoid foramen to the frontal region. RESULTS: In the fronto-temporal region, above the zygomatic arch, FTB gives several small twigs running anteriorly in the fat pad above the superficial temporalis fascia and a branch within the temporo-parietal fascia (TPF) to the muscles of the forehead. There were no twigs of the FTB within the interfascial fat pad. CONCLUSIONS: No branches of the FTB are found in the interfascial (between the superficial and deep leaflet of the temporalis fascia) fat pad. The interfascial dissection can be safely performed without risk of injury to the FTB and potential subsequent frontalis palsy.

Petrosectomy and Topographical Anatomy in Traditional Kawase and Posterior Intradural Petrous Apicectomy (PIPA) Approach: An Anatomical Study.

OBJECTIVE: To compare the anatomical exposure and petrosectomy extent in the Kawase and posterior intradural petrous apicectomy (PIPA) approaches. METHODS: Kawase and PIPA approaches were performed on 4 fixed cadaveric heads (3 alcohol-fixed, 1 formaldehyde-fixed silicone-injected; 4 Kawase and 4 PIPA approaches). The microsurgical anatomy was examined by means of Zeiss Opmi CS/NC-4 microscopes. HD Karl Storz Endoscopes (AIDA system) were used to display intradural exposure. Petrosectomy volumes was assessed by comparing pre- and postoperative thin-slice computed tomography scans (Analyze 12.0; AnalyzeDirect Mayo Clinic). RESULTS: The Kawase approach exposed the rhomboid fossa with Meckel's cave extradurally, the upper half of the clivus, superior cerebellopontine angle, ventrolateral brainstem, the intrameatal region, basilar apex, and the preganglionic root of cranial nerve (CN) V, CN III-IV-VI intradurally. The PIPA approach exposed the cerebello-pontine angle with CN VI-XII, Meckel's cave, CN III-V, and the middle and lower clivus intradurally from a posterior view. The area of surgical exposure is wide in both approaches; however, the volume of petrosectomy, the working angle, and surgical corridor differ significantly. CONCLUSIONS: The Kawase approach allows wide exposure of the middle cranial fossa (MCF) and posterior cranial fossa, requiring extradural temporal lobe retraction and an extradural petrosectomy with preservation of the internal acoustic meatus and cochlea. No temporal lobe retraction and direct control of neurovascular structures make the PIPA approach a valid alternative for lesions extending mostly in the Posterior cranial fossa with minor extension in the MCF. The longer surgical corridor, cerebellar retraction, and limited exposure of the anterior brainstem make this approach less indicated for lesions with major extension in the MCF and the anterior cavernous sinus.

Glossopharyngeal neuralgia treated with an endoscopic assisted midline suboccipital subtonsillar approach: technical note.

BACKGROUND: Glossopharyngeal nerve neuralgia (GPN) is an exceptionally rare skull-based disorder. It is treated similar to other neurovascular conflicts. The approach, however, is debatable, as the caudal cranial nerves and especially the exit zones at the brainstem are barely visible via the retrosigmoid approach. CLINICAL PRESENTATION: We demonstrate a case of a typical GPN with microsurgical neurovascular decompression according to standard procedures. Continuous electrophysiological monitoring, including motor-evoked potentials of the glossopharyngeal nerve in addition to somatosensory evoked potential (SSEP) monitoring, was set up. In prone position a midline suboccipital osteoplastic craniotomy was performed. Intradurally, an endoscopic-assisted subtonsillar exposure of the lateral recess and the nerve root exit zone of the glossopharyngeal nerve has been chosen. A large compressing branch of the posterior inferior cerebellar artery (PICA) was identified as the cause of the neurovascular conflict and transposed. CONCLUSIONS: A midline subtonsillar approach with endoscopic assistance to the lateral brainstem is a straightforward time- and morbidity-sparing procedure.

Visualization of the anterior cerebral artery complex with a continuously variable-view rigid endoscope: new options in aneurysm surgery.

BACKGROUND: Neuroendoscopy is increasingly used as an adjunctive tool in intracranial aneurysm surgery. OBJECTIVE: To assess the versatility of a prototype continuously variable-view rigid endoscope in visualizing the anterior cerebral artery complex. METHODS: In 5 formaldehyde-fixed, arterially injected specimens, a standard frontolateral approach was used on both sides. After meticulous microsurgical dissection using this approach, the prototype of a multivariable rigid endoscope (EndoCAMeleon; Karl Storz GmbH & Co, Tuttlingen, Germany) was inserted. It is a rigid endoscope that is capable of changing its angle of view while remaining stationary and shape invariant. We inspected the anterior cerebral artery complex, using and testing the capabilities of the device. RESULTS: The continuously variable viewing mechanism enables the surgeon to adjust the field of view continuously and to optimize the visualization of the neurovascular structures. Because of the rigid tip combined with the continuously variable viewing mechanism, the need to move the endoscope within the surgical field was minimal. The field of view changes, but the tip itself hardly moves. The EndoCAMeleon was able to enhance both the visibility of the anterior cerebral artery complex and the accessibility of the A1 and A2 arterial walls to a range of approximately 270 degrees. CONCLUSION: The EndoCAMeleon enhances the visibility of the anterior cerebral artery complex and facilitates endoscope-assisted inspection, planning of clip application, and clip control.

SIADH following pituitary adenoma apoplexy.

The rare case of a patient with SIADH following pituitary adenoma apoplexy is reported. Since apoplexy did not exert any mass effect on surrounding structures, the patient was treated conservatively and the anterior pituitary gland insufficiency has been substituted adequately. Seven days after the apoplexy the patient again showed low serum-Na(+) levels despite cortisol substitution. Diagnosis of SIADH was made. It is essential to be aware of this rare syndrome in patients with pituitary adenoma apoplexy.

Dual cross-talk between nitric oxide and D-serine in astrocytes and neurons in the brain.

The present review describes the role of the putative cross-talk between two neurotransmitters, nitric oxide (NO) and D-serine, in the brain. Under physiological conditions NO homeostasis guarantees the correct function of NO in a number of events in the brain such as neurotransmission and vascular tone regulation. D-serine, produced in astrocytes, acts synergistically with glutamate at NMDA receptors on postsynaptic neurons. Neuronal and endothelial NO synthase (nNOS and eNOS) in astrocytes cross-talk with serine racemase (SR) and D-amino acid oxydase (DAAO), catalyzing the synthesis and degradation of D-serine, respectively. SR is inhibited by NO which activates DAAO. D-serine inhibits nNOS but not eNOS and activates SR. Astrocytes and neurons also cross-talk through NO/D-serine system. D-serine released from astrocytes induces a rapid increase in NO contents in postsynaptic neurons. Overall, D-serine production in astrocytes is negatively regulated by NO. Under inflammatory conditions, pro-inflammatory cytokines or Abeta induce, first, a drop in NO contents and an increase in the amounts of D-serine in astrocytes. Together with enhanced glutamate release from presynaptic neurons, D-serine induces an increase in Ca(2+) up-take into presynaptic neurons. In astrocytes an initial drop in NO contents triggers NF-kappaB activation followed by inducible NOS (iNOS) expression. iNOS-derived massive amounts of NO may potentially be toxic. Under schizophrenic conditions, D-serine production is down-regulated. Together with reduced glutamate release, this situation leads to the decreased NO production in postsynaptic neurons. In astrocytes induction of iNOS expression becomes predominant. Initial drop in nNOS-derived NO is potentially toxic in this scenario.