Aqueductal stenting with an intra-catheter endoscope--a technical note.

INTRODUCTION: Aqueductoplasty as well as aqueductal stenting is an accepted therapy option in short-segment aqueductal stenosis and isolated fourth ventricle. Over the years, different techniques with only slight modifications by using a conventional neuroendoscope with a working sheath to introduce different instruments have been presented. In summary, the use of Fogarty balloon catheters or flexible endoscopes to pass the narrowed aqueduct is recommended. METHODS: This technical report describes a substantially new technique for this purpose. Six patients underwent aqueductal stenting with a new intracatheter endoscope. RESULTS: Aqueductal stenting was possible in 4 out of 6 cases. No complications occurred. Handling of this new technique was good and easy without a prolonged learning curve. All four stents did work appropriately, and the procedure was considered to be successful. Of the two failures, the technique was abandoned and endoscopic third ventriculostomy (ETV) was performed in one. In the other case, suboccipital shunting was done. CONCLUSION: This technical report describes a substantially new technique for aqueductal stenting. The combination of an intracatheter miniature endoscope and a prepared ventricular catheter enables careful and elegant aqueductal stenting. Large or flexible endoscopes, balloons, or special instruments to place a stent have become completely obsolete in selected cases.

Surviving a Self-inflicted Transorbital Pen Intrusion to the Cerebellum: Case Report.

BACKGROUND: Although intracranial traumas by penetrating foreign objects are not absolute rarities, the nature of trauma, the kind of object, and its trajectory make them a one of a kind case every time they occur. Whereas high-velocity traumas mostly result in fatalities, it is the low-velocity traumas that demand an individualized surgical strategy. METHODS: We present a case report of a 33-year-old patient who was admitted to our department with a self-inflicted transorbital pen injury to the brain. The authors recall the incident and the technique of the pen removal. RESULTS: Large surgical exposure of the pen trajectory was considered too traumatic. Therefore, we opted to remove the pen and have an immediate postoperative computed tomography (CT) scan. Due to its fragility, the pen case could only be removed with a screwdriver, inserted into the case. Post-op CT scan showed a small bleeding in the right peduncular region, which was treated conservatively. The patient was transferred back to intensive care unit and woken up the next day. She lost visual function on her right eye, but suffered from no further neurologic deficit. CONCLUSION: Surgical management of removal of intracranial foreign bodies is no routine procedure. Although some would favor a large surgical exposure, we could not think of an approach to do so without maximum surgical efforts. We opted for a minimal surgical procedure with immediate CT scan and achieved an optimal result. We find this case to be worth considering when deciding on a strategy in the future.

Single-step resection and reconstruction of orbito-fronto-temporal pathologies using a PMMA CAD-implant.

BACKGROUND: Resection of bone infiltrating meningiomas of the sphenoid plane and the orbital walls is a highly challenging neurosurgical procedure. In this study, the authors present 11 cases of fronto-orbital and sphenoid wing meningioma which were subjected to tumor resection and cranioplasty using a pre-designed CAD PMMA-implant in one single staged procedure. METHODS: Eleven cases were prospectively analyzed from January 2011 to December 2018. In all cases preoperative CT scans were performed and evaluated, in order to produce a customized PMMA-implant, fitting the osseous defect left after surgical resection of the predefined tumorous mass. Surgery was performed with standard techniques with the addition of availability of preplanned neuronavigational data as well as a matching template of the implant for intraoperative use. After tumor resection, cranioplasty followed using the predesigned PMMA implant. RESULTS: Gross total resection was achieved in 82% (9 of 11 cases). Mean time of surgery for the combined procedure resulted in 223min±99min, with a mean blood loss of 427±192cc. Mean hospital stay for the combined procedure resulted in 11.5±3 days. In 18% of the cases (2/11), patients suffered from late onset infection of the implant and needed a surgical removal. CONCLUSIONS: The presented data show that gross total resection and subsequent single staged bone reconstruction in osseous sphenoid wing and orbital rim meningiomas can be achieved using predesigned PMMA CAD implants with preplanned tumor resection borders with neuronavigational guidance.

Bisulfite profiling of the MGMT promoter and comparison with routine testing in glioblastoma diagnostics.

BACKGROUND: Promoter methylation of the DNA repair gene O6-methylguanine-DNA methyltransferase (MGMT) is an acknowledged predictive epigenetic marker in glioblastoma multiforme and anaplastic astrocytoma. Patients with methylated CpGs in the MGMT promoter benefit from treatment with alkylating agents, such as temozolomide, and show an improved overall survival and progression-free interval. A precise determination of MGMT promoter methylation is of importance for diagnostic decisions. We experienced that different methods show partially divergent results in a daily routine. For an integrated neuropathological diagnosis of malignant gliomas, we therefore currently apply a combination of methylation-specific PCR assays and pyrosequencing. RESULTS: To better rationalize the variation across assays, we compared these standard techniques and assays to deep bisulfite sequencing results in a cohort of 80 malignant astrocytomas. Our deep analysis covers 49 CpG sites of the expanded MGMT promoter, including exon 1, parts of intron 1 and a region upstream of the transcription start site (TSS). We observed that deep sequencing data are in general in agreement with CpG-specific pyrosequencing, while the most widely used MSP assays published by Esteller et al. (N Engl J Med 343(19):1350-1354, 2000. https://doi.org/10.1056/NEJM200011093431901 ) and Felsberg et al. (Clin Cancer Res 15(21):6683-6693, 2009. https://doi.org/10.1158/1078-0432.CCR-08-2801 ) resulted in partially discordant results in 22 tumors (27.5%). Local deep bisulfite sequencing (LDBS) revealed that CpGs located in exon 1 are suited best to discriminate methylated from unmethylated samples. Based on LDBS data, we propose an optimized MSP primer pair with 83% and 85% concordance to pyrosequencing and LDBS data. A hitherto neglected region upstream of the TSS, with an overall higher methylation compared to exon 1 and intron 1 of MGMT, is also able to discriminate the methylation status. CONCLUSION: Our integrated analysis allows to evaluate and redefine co-methylation domains within the MGMT promoter and to rationalize the practical impact on assays used in daily routine diagnostics.

Reaching the sellar region endonasally - One or both nostrils? A pilot study in body donors.

INTRODUCTION: The purpose of this study was to evaluate the effect of posterior septectomy size on surgical exposure and surgical freedom during the endoscopic transsphenoidal approach to the sellar and parasellar region. METHODS: A mononostril and binostril approach to the sellar region was performed on 4 formalin-fixed cadaveric heads. Predefined anatomical structures were identified. Additionally, a millimeter gauge was introduced into the surgical site and the extent of dorsal septectomy was analyzed for both approaches. Surgical freedom was defined as the distance between the ipsilateral and contralateral limit of opening of the sphenoid sinus. RESULTS: The mean extent of dorsal septectomy was 15.7±5.7mm using a binostril approach to achieve adequate visualization of all relevant anatomical structures. Superior results were obtained via binostril technique with respect to the ability to identify the contralateral internal carotid artery or opticocarotid recessus. No such advantage was found for all other landmarks. Surgical freedom between the ipsilateral and contralateral limit of exposure of the sphenoid sinus was measured with 15±0.8mm in the mononostril and 19.2±0.9mm in the binostril group. CONCLUSIONS: The surgical exposure increased significantly with progressively larger posterior septectomy in binostril approaches until a 20-mm posterior septectomy. Bilateral lateral opticocarotid recesses were accessible with a mean of 15mm for posterior septectomy. In the mononostril group no dorsal septectomy was necessary. Thus, the nasal mucosa is more preserved by this technique. However, the lateral exposure is partially limited and the use of angled endoscopes is recommended when adopting a mononostril approach to the sellar region.

Intracranial Pressure-Guided Shunt Valve Adjustments with the Miethke Sensor Reservoir.

BACKGROUND: Telemetric intracranial pressure (ICP) monitoring seems to be a promising therapy-supporting option in shunt-treated patients. Benefits become obvious when headaches are unspecific and clinical symptoms cannot be related to possible overdrainage or underdrainage. In this study, we evaluated a new telemetric device to individually adjust shunt valves according to ICP measurements. METHODS: Between December 2015 and November 2016, 25 patients with suspected suboptimal shunt valve settings underwent insertion of a telemetric ICP sensor (Sensor Reservoir; Christoph Miethke, Potsdam, Germany). Over a 1-year period, a total of 183 telemetric ICP measurements and 85 shunt valve adjustments were carried out. Retrospective statistic analyses focused on valve adjustments, ICP values, and clinical outcomes. RESULTS: ICP-guided valve adjustments positively changed the clinical state in 18 out of 25 patients. Clinical improvement over time was associated with significant changes of the valve settings and ICP values. Interestingly, a therapeutically normalized ICP profile was not automatically associated with clinical improvement. CONCLUSIONS: The Sensor Reservoir is an important and valuable tool for shunt-treated patients suffering from drainage-related problems. The possibility to simultaneously recognize and solve shunt problems represents the decisive advantage. Nevertheless, measurements with the Sensor Reservoir did not allow for the determination of default valve settings or universal target ICP values.

Confocal Laser Endomicroscopy in Neurosurgery-An Alternative to Instantaneous Sections?

OBJECTIVE: Intraoperative distinction of brain tumor from surrounding brain is a crucial challenge in neuro-oncologic surgery. We directly compared confocal laser endomicroscopy (CLE) findings with intraoperative instantaneous sections by the neuropathologist in a blinded fashion. METHODS: The imaging device comprises a rigid endoscope with Hopkins rod lenses and a red wave length laser with a scanning depth of 80 µm. Brain tumor samples of 100 patients were investigated. Tissue samples were simultaneously investigated by the neuropathologist and with CLE. The tissue was not prepared or stained before CLE analysis. RESULTS: CLE could be performed in all cases. Sensitivity for detection of a correct final diagnosis by CLE on site was 82%-90% for high-grade gliomas (26/32), low-grade gliomas (9/10), schwannomas (7/8), and meningiomas (28/34). Sensitivity of only 37% (6/16) was achieved for metastasis (6/16). CONCLUSIONS: With intraoperative CLE, it is possible to obtain an on-site histologic diagnosis with a high sensitivity in many tumors. Although definitive histologic classification requires further neuropathologic investigation, these results show that CLE could fill the gap between tissue resection and microscopic analysis. This could ultimately help neurosurgeons to scan brain tissue for tumor remnants on a microscopic scale without having to resect it first. Further development of the device and further investigations are needed before this technique can become part of the neurosurgical routine in specific cases.

Telemetric Intracranial Pressure Monitoring with the Raumedic Neurovent P-tel.

BACKGROUND: Devices enabling long-term intracranial pressure monitoring have been demanded for some time. The first solutions using telemetry were proposed in 1967. Since then, many other wireless systems have followed but some technical restrictions have led to unacceptable measurement uncertainties. In 2009, a completely revised telemetric pressure device called Neurovent P-tel was introduced to the market. This report reviews technical aspects, handling, possibilities of data analysis, and the efficiency of the probe in clinical routine. METHODS: The telemetric device consists of 3 main parts: the passive implant, the active antenna, and the storage monitor. The implant with its parenchymal pressure transducer is inserted via a frontal burr hole. Pressure values can be registered with a frequency of 1 Hz or 5 Hz. Telemetrically gathered data can be viewed on the storage monitor or saved on a computer for detailed analyses. A total of 247 patients with suspected (n = 123) or known (n = 124) intracranial pressure disorders underwent insertion of the telemetric pressure probe. RESULTS: A detailed analysis of the long-term intracranial pressure profile including mean values, maximum and negative peaks, pathologic slow waves, and pulse pressure amplitudes is feasible using the detection rate of 5 Hz. This enables the verification of suspected diagnoses as normal-pressure hydrocephalus, benign intracranial hypertension, shunt malfunction, or shunt overdrainage. Long-term application also facilitates postoperative surveillance and supports valve adjustments of shunt-treated patients. CONCLUSIONS: The presented telemetric measurement system is a valuable and effective diagnostic tool in selected cases.

Confocal laser endomicroscopy in neurosurgery: a new technique with much potential.

Technical innovations in brain tumour diagnostic and therapy have led to significant improvements of patient outcome and recurrence free interval. The use of technical devices such as surgical microscopes as well as neuronavigational systems have helped localising tumours as much as fluorescent agents, such as 5-aminolaevulinic acid, have helped visualizing pathologically altered tissue. Nonetheless, intraoperative instantaneous frozen sections and histological diagnosis remain the only method of gaining certainty of the nature of the resected tissue. This technique is time consuming and does not provide close-to-real-time information. In gastroenterology, confocal endoscopy closed the gap between tissue resection and histological examination, providing an almost real-time histological diagnosis. The potential of this technique using a confocal laser endoscope EndoMAG1 by Karl Storz Company was evaluated by our group on pig brains, tumour tissue cell cultures, and fresh human tumour specimen. Here, the authors report for the first time on the results of applying this new technique and provide first confocal endoscopic images of various brain and tumour structures. In all, the technique harbours a very promising potential to provide almost real-time intraoperative diagnosis, but further studies are needed to provide evidence for the technique's potential.