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Peripheral nerve tumors (PNT) are rare lesions. To date, no systematic multicenter studies on epidemiology, clinical symptoms, treatment strategies and outcomes, genetic and histopathologic features, as well as imaging characteristics of PNT were published. The main goal of our PNT Registry is the systematic multicenter investigation to improve our understanding of PNT and to assist future interventional studies in establishing hypotheses, determining potential endpoints, and assessing treatment efficacy.Aims of the PNT registry were set at the 2015 Meeting of the Section of Peripheral Nerve Surgery of the German Society of Neurosurgery. A study protocol was developed by specialists in PNT care. A minimal data set on clinical status, treatment types and outcomes is reported by each participating center at initial contact with the patient and after 1 year, 2 years, and 5 years. Since the study is coordinated by the Charité Berlin, the PNR Registry was approved by the Charité ethics committee (EA4/058/17) and registered with the German Trials Registry (www.drks.de). On a national level, patient inclusion began in June 2016. The registry was rolled out across Europe at the 2019 meeting of the European Association of Neurosurgery in Dublin.Patient recruitment has been initiated at 10 centers throughout Europe and 14 additional centers are currently applying for local ethics approval.To date, the PNT registry has grown into an international study group with regular scientific and clinical exchange awaiting the first results of the retrospective study arm.

Despite enormous research efforts, the disease mechanisms causing multiple sclerosis (MS) are still incompletely understood, suggesting a complex and multifaceted pathogenesis. Here, we report the clinical observation that in a designated German center for Neurofibromatosis type 2 (NF2), the number of MS cases among NF2 patients is higher than in the general population. Epidemiological studies investigating a connection between NF2 and MS are difficult to perform due to the rarity of NF2 disease. However, based on the current pathophysiological concepts, we hypothesize that genetically determined vulnerability of peripheral nerves and repeated nerve repair processes might constitute an unrecognized factor to the pathogenesis of MS and might explain the apparent over-representation of MS cases among NF2 patients.

Objective Over the past few years bipolar electrocoagulation techniques in neurosurgery have been continually improving. However, limited access during endoscopic endonasal transsphenoidal surgery (EETS) for central skull base pathologies and the requirement of very precise coagulation in that dedicated anatomical area requires further refinement of bipolar coagulation instruments. We describe our experience (effectiveness of coagulation, intraoperative handling, and the use as a dissecting tool) with a new type of coagulation forceps, the Calvian endo-pen (Sutter Medizintechnik, Freiburg, Germany) during EETS. Method From June to August 2015, 12 patients with central skull base lesions (9 with a pituitary adenoma and 1 each with epidermoid, hemangioma, and juvenile angiofibroma) were operated on with the Calvian endo-pen. Results The application of the Calvian endo-pen was feasible in all cases. The angled thin tips proved to be very effective and precise for soft tissue coagulation to achieve hemostasis. Even very small vessels could be occluded selectively. It was also helpful for outward dissection in separating normal from tumor tissue. Conclusion The use of the Calvian endo-pen is safe and effective during EETS for central skull base pathologies. Its ease in intraoperative handling (maneuverability, cleaning) and precise coagulation makes it a promising instrument for EETS.

To analyse whether the WHO grade of intracranial meningiomas differs itself depending on patients and meningioma characteristics at diagnosis. Single center retrospective study of a series of consecutive patients with primary intracranial meningiomas who underwent surgery between January 2007 and March 2014. Patients (age, sex, outcome) and meningioma characteristics (histological diagnosis, tumor location, WHO grading, size, extend of peritumoral edema and tumor recurrence rate) were analysed. Of 240 included patients, 184 (76.7%) were female and 56 (23.3%) were male. 17 patients (7.1%) were in age group 20–40 years, 112 (46.7%) in group 41–60 years and 111 (46.3%) were in age group > 60 years. 189 patients (78.8%) were diagnosed with WHO grade I, 49 (20.4%) WHO grade II and 2 (0.8%) had a WHO grade III meningioma. WHO grade II meningiomas were significantly more frequent in the age group 20–40 years compared to age group 41–60 years (chi-square p

To date, few studies have been published about the growth dynamics of tumors associated with neurofibromatosis type-2 (NF2), none of which evaluated gender-specific differences. Our aim was to compare radiographic data of female and male patients with NF2.MR images of 40 patients (20 female, 20 male) from the regional NF2 referral center were included in this analysis. Tumor sizes were determined by semi-automated volumetric measurement. Intracranial tumors were measured on post-contrast T1-weighted MRI datasets and volumes of intramedullary spinal tumors were determined from sagittal T2-weighted MRI datasets.The median follow-up time was 91 months (range, 16-199 months) per patient. Intracranial tumors: On average, female patients had 13.4 neoplasms, while male patients had 6.75 (p = 0.042). The overall median time to tumor progression of ≥20 % was 20 months for females and 18 months for males. Tumors of the cerebellopontine angle (CPA) that had undergone previous surgery had shorter progression-free intervals in females than in males (16 and 24 months, respectively; p = 0.012). The median 1-year growth rate was 17.5 ± 44.6 % in females compared to 12.5 ± 44.9 % in males (p = 0.625). Intramedullary spinal tumors: On average, females had 2.05 tumors and males had 1.75 tumors (p = 0.721). Median time to tumor progression was 21 months in females and 44 months in males (p = 0.204). After 2 years, the median growth rate was 24.4 ± 56.8 % in female and 13.5 ± 40.4 % in male patients (p = 0.813).The radiographic data in this study suggest that female patients are affected by a greater number of tumors than male patients and that post-surgery tumors of the CPA grow faster in females than in males.

Objectives Volumetric data on the natural growth of intramedullary tumors in patients with neurofibromatosis type 2 (NF2) are rare, but crucial for long-term disease monitoring. Our aim was to evaluate the growth rates and growth patterns of these tumors. Patients and methods Patient records from the regional neurofibromatosis referral center were evaluated for inclusion in this analysis. Magnetic resonance images of the spine were collected and digitized as necessary. Tumor volumes were determined by volumetric extrapolation after segmentation in datasets (iPlan Net software, BrainLAB, Munich) if the tumors met the following inclusion criteria: sagittal T2-weighted MRI scans had to be available from at least two investigations and tumors had to be visible on at least two slices. All tumors that had undergone previous therapy, such as surgery, radiation or bevacizumab treatment were excluded from this study. Results Suitable MR images of the spine were available from 51 patients (20 males, 31 females) with NF2. The median follow-up time per patient was 54 months (range 0–190 months). 23 patients (15 females, 11 males) of the 51 patients with spinal imaging harbored intramedullary tumors. Across this cohort, there was an aggregate of 68 tumors at baseline. Over the course of follow-up, the patients developed 19 additional tumors, resulting in a total of 87 tumors. A final set of 42 tumors from 19 patients met the inclusion criteria and was included in the growth analysis. The median follow-up time per tumor was 44 months (range 9–122 months). 23 of the tumors were located in the cervical spine; 19 of them were located in the thoracic spine. The median tumor size ± standard deviation (SD) after 5 years was 136 ± 71.0% compared to baseline. The median time to ≥20% tumor growth was 24 months. Overall, 30 tumors (71.4%) grew, 8 (19.1%) remained stable and 4 (9.52%) decreased in size. The most common growth pattern was saltatory growth. Conclusion Intramedullary spinal cord tumors are present in about half of patients with NF2. The majority of these tumors grow over time, albeit slowly. Given the confines of the spinal medulla and the limited scope for functional recovery after symptomatic tumor expansion, NF2 patients should be under continual surveillance in order to rapidly identify intramedullary spinal tumors that may require microsurgical resection.

Comorbidity of neurofibromatosis type 2 (NF2) and multiple sclerosis (MS) has rarely been reported. Since immunological mechanisms have been implicated in Nf2, coexistence of the two entities may offer insights into schwannoma pathogenesis with respect to the impact of the immune system. We present the case of a woman with a de novo mutation in the NF2 gene who later developed MS. In addition, we found a significantly higher count of T cells in a laryngeal schwannoma of this patient as compared to a schwannoma removed from a NF2 patient without MS. This finding correlated with a higher growth rate in the case of NF+MS.

Background Endoscopic endonasal transsphenoidal surgery (EETS) is a common treatment for patients with pituitary adenomas (PAs). A disadvantage of endoscopic surgery has been the lack of stereoscopic vision and depth perception. Recent developments offer high-definition 3-dimensional (3D-HD) visualization with a higher resolution and better image quality compared with 3D standard endoscopy (3D-SD). In this study, we compared treatment results of surgically treated patients with PAs using 3 different visualization systems: 2-dimensional (2D)-HD, 3D-SD, and 3D-HD. Methods Data from patients with primary PAs that were surgically treated between December 2008 and December 2017 were analyzed. Preoperative and postoperative tumor size and location, perioperative complications, and ophthalmologic, endocrine, and clinical outcomes were compared. Results A total of 170 patients underwent endoscopic resection of a primary PA (54 patients with 2D-HD, 75 with 3D-SD, and 41 with 3D-HD). Preoperatively, no statistical differences were found for tumor size, extension, and endocrine and ophthalmologic status. Tumor resection was not statistically different among the 3 groups. Complete resection was performed in 33 patients (80%) in the 3D-HD group, 54 patients (72%) in the 3D-SD group, and 39 patients (72%) in the 2D-HD group. The number of complications was not different across the groups (P = 0.436). Ophthalmologic outcomes did not differ based on EETS technique. The rate of new pituitary insufficiency was slightly lower in the 3D-HD group compared with 2D-HD and 3D-SD groups (4.8%, 16.6%, and 12%, respectively; P = 0.290). Conclusions Although the resection rate was higher in the 3D-HD group, and subjective advantages of the 3D-HD endoscopes were noted, there were no significant differences in terms of gross total resection or new hormonal deficits among the 3 groups.

A female patient operated at the age of 11 on a pilocytic astrocytoma in the posterior fossa, was re-operated for a recurrence 9 years later. A Torkildsen drain was placed in the 4th ventricle and she remained asymptomatic for 15 years before presenting again with acute hydrocephalus, tonsillar herniation, and a massive cervicothoracic syrinx. The symptoms retreated following craniocervical untethering and decompression. Two weeks later, however, she suffered from debilitating radiculopathy provoked by tethering of the cauda equina. Again, symptoms retreated completely after microsurgical intervention. This combination of a secondary Chiari-like malformation with cervical syringomyelia and tethering of the cauda equina in a single patient as a delayed complication of posterior fossa surgery has not been reported before. Diagnosis and treatment of lower tethered cord syndrome may be obscured and delayed in complex clinical situations. In particular, awareness to symptoms that are not related to syringomyelia is important in patients with a known syrinx and a history of posterior fossa surgery.

Objective To evaluate efficacy and reliability of intraoperative Doppler sonography in localizing the transverse and sigmoid sinuses during lateral suboccipital craniotomy. Methods A 16-Mhz intraoperative micro-Doppler ultrasound (16Mhz, Multi-Dop pro, Compumedics, Singen, Germany) was applied to detect the medial border of the sigmoid sinus and the inferior border of the transverse sinus in 25 patients. Micro-Doppler measurements were compared with magnetic resonance- and computed tomography-based image guidance (Kolibri, Brainlab, Munich, Germany). Visual detectability of the sinuses with the operating microscope was also documented. Results Inadvertent incision of the transverse or sigmoid sinuses did not occur in any patient when the 2 localizing methods have been used in combination. The mean mismatch of image-guided system and micro-Doppler was 2.64 mm (range, 0–6 mm; standard deviation, 1.55 mm). With the microscope the transverse sinus was invisible in 7 patients, the sigmoid sinus was visually undetectable in 1 case. The micro-Doppler indicated blood flow outside the visible borders of the sinuses in 5 patients. Conclusions A combination of image-guidance and micro-Doppler enhances the accuracy in localizing the margins of the transverse and sigmoid sinuses using the retrosigmoid approach, thus preventing inadvertent injury. The method could potentially be applied during other craniotomies involving the exposure of a venous sinus.

Object Recording the auditory brainstem response (ABR) is a common method for monitoring the integrity of auditory pathways during surgery in the cerebellopontine angle. Electrocochleography (ECochG) is an alternative means of intraoperative neuromonitoring. In the present study the authors compared the practicability and prognostic significance of these two methods by performing simultaneous recordings in the operating room. Methods Between 2006 and 2011, 125 patients (mean age 55 years) underwent surgery in the cerebellopontine angle. Seventy-one percent of the patients presented with a hearing deficit, and 37% had useful hearing but with slight functional impairment. Auditory brainstem response was recorded with a subdermal needle electrode at the mastoid. For ECochG recording, a noninvasive ball electrode was attached to the tympanic membrane. Amplitudes obtained from both ECochG and ABR audiometry were compared and correlated to pre- and postoperative hearing deficits. Results Simultaneous intraoperative monitoring via ABR and ECochG was possible in 114 cases (91%). Postoperatively, 42% of patients showed some degree of new hearing deficit, whereas 4% had improvement. The mean amplitudes in ECochG monitoring were significantly higher (0.18 ± 0.04 μV) than the ABR potentials (0.08 ± 0.006 μV; p < 0.05). All waves recorded at the mastoid needle electrode could be recognized in the potentials of the tympanic ball electrode. Hearing outcome correlated more reliably with the relative amplitude changes in Waves III and V in ECochG (III: p = 0.0008, V: p = 0.0015) than in ABR monitoring (III: p = 0.2075, V: p = 0.0398). Conclusions Intraoperative monitoring of the auditory system by recording with noninvasive tympanic ball electrodes is more practicable than with subcutaneous needle electrodes at the tragus. Since there is also a reliable correlation between ECochG and clinical outcome, the method can replace common ABR recording during surgery in the cerebellopontine angle.

Actinomycosis of the spine with spinal cord compression is rare. Only 22 cases are reported in the literature. The authors describe a remarkable case of a large lesion leading to bony destruction and spinal cord compression in the cervicothoracic junction with a large intrathoracic extension, which was considered to be a metastatic pulmonary disease but turned out to be actinomycosis. Clinical Presentation A 55-year-old man presented with acute tetraparesis. Magnetic resonance imaging (MRI) and computed tomography (CT) imaging showed vertebral body collapse of T1 and partially C7 with spinal cord compression as well as a mass in the right upper lobe with multiple intrapulmonary nodules. Moreover, dorsal elements (laminae and spinous process) were also involved and partially destructed. Differential diagnosis favored metastatic pulmonary disease. Intervention Decompression surgery was performed by anterior corpectomy of T1, stabilization with an expandable titanium cage and additional anterior plate C7–T2. Histology revealed typical sulfur granules. Microbiology exams were positive for Actinobacillus actinomycetemcomitans. There was no proof of malignancy in thoracic biopsy in the late diagnostic work-up. To prevent instrumentation failure, an external immobilization (halo fixation) was applied until complete fusion was documented in CT during the postoperative course. After an 11-month course of ampicillin/sulbactam, there was complete resolution of the intrapulmonary and spinal pathology. Conclusion Thoracic actinomycosis with spinal involvement is a rare disease. Therefore, diagnosis may be difficult. Surgical intervention, correct diagnosis, and specific long-term antibiotic treatment resulted in favorable outcome.

Background Classic trigeminal neuralgia is often treated pharmacologically first. However, microvascular decompression (MVD) or radiosurgical treatment (RS) can render medication unnecessary. Objective appraisals of the 2 treatment modalities are scarce. Objective To compare the evidence regarding safety and efficiency of MVD and RS. Methods We searched PubMed for studies describing pain control, complications, and recurrences after MVD or RS between 2005 and 2015. Because randomized studies are lacking, we focused the statistical analysis on cohort clinical trials. Differences in outcome after treatment with either MVD or RS were analyzed using t tests and weighted averages. PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed. Results Fifty-three studies (13,805 patients, in 11 prospective and 42 retrospective studies) were analyzed. Initial success rates were 71.1% for RS and 86.9% for MVD (P 5 years after intervention), success rates decreased to 63.8% for RS versus 84% for MVD (P = 0.036). Thirty-six months after the intervention, median percentage of recurrence was 11% for MVD and 25% for RS (P = 0.0015). The length of recurrence-free intervals was similar for MVD and RS (30.45 vs. 30.55 months; P = 0.987). There was no significant difference between the incidence of hearing loss after MVD and RS (1.51% vs. 0.74%; P = 0.21). Facial dysesthesia was reported more frequently after radiosurgery (2.3% vs. 28.8%; P = 0.02). Conclusions MVD is a valid first-line treatment option for young patients free of comorbidities. First-line RS can be advised in patients with a higher surgical risk.

Background Arachnopathy following meningitis has been described in the setting of chronic spinal arachnoiditis and more recently as shunt-related progressive myelopathy due to meningeal thickening. Case Description We describe an atypical case of a patient who presented with chronic arachnopathy 5 decades after an episode of meningitis. We also review the literature concerning arachnopathies occurring in the context of early childhood meningitis. Although our case bore clinical and radiologic similarities to chronic spinal arachnoiditis and shunt-related progressive myelopathy, time to symptom onset, intraoperative findings, pathophysiology, and surgical outcome set it apart from both conditions. Conclusions It is challenging but worthwhile to recognize this separate entity because, in contrast to both shunt-related progressive myelopathy due to meningeal thickening and adhesive arachnoiditis, surgery involving microsurgical dissection of the thick arachnoid encasement of the cauda equina may be curative in medically refractory cases.

Objective Patients with neurofibromatosis type 2 (NF2) are prone to develop multiple intracranial neoplasms, such as schwannomas of the cranial nerves and meningiomas. The aim of our study was to investigate 1) the median growth rate per year, 2) the growth-free interval, and 3) the growth patterns of NF2-associated intracranial tumors. Methods All available magnetic resonance (MR) images of patients from the regional neurofibromatosis center were collected. The depicted tumors' volumes were then calculated if the tumors met the following inclusion criteria: contrast enhanced T1-weighted MRI datasets had to be available from at least two investigations and tumors had to be measurable on at least two slices. Results One-hundred and eighty-eight tumors from 52 patients (20 male, 32 female) met the inclusion criteria for volumetric analysis. Overall, the median follow-up time was 76.5 months per patient (range 13–199 months). After 5 years, the median tumor size was 196% ± 338% for vestibular schwannomas (VS), 204% ± 702% meningiomas (M), 128% ± 64.9% for non-vestibular schwannomas (NVS) and 139% ± 270% for pre-operated tumors of the cerebellopontine angle (TX), respectively. The median time to 20% tumor progression was 21 months for VS, NVS and TX, and 17 months for M. Overall, saltatory growth was the most common growth pattern (46.9%). Conclusions Most NF2-associated tumors display a saltatory growth pattern. Meningiomas and untreated vestibular schwannomas grow rapidly and overall at similar rates. Tumors of the CPA that have been operated on and non-vestibular schwannomas show less relative growth per year.

To evaluate patients with complex aneurysms who underwent waffle-cone stent-assisted coil embolization.From February 2008 to February 2010, consecutive data were collected from 80 patients with aneurysms treated with the Solitaire™ AB Remodeling Device followed by a standard coiling procedure using bare or/and bioactive coils. Six of these patients were treated using the "waffle-cone-technique" placing the distal end of a stent directly into the base of a bifurcation aneurysm and coiling through the expanded and cone-shaped distal end of the stent allowing for preservation of parent artery patency. The aneurysms were located at the P3 segment of the posterior cerebral artery (n = 1), the middle cerebral artery bifurcation (n = 1), the basilar tip (n = 2), and the AComAnt (n = 2). Four patients underwent follow-up (2-7 months, mean 4.5 months).Waffle-cone positioning of the Solitaire™ AB Remodeling Device was obtained in all cases without technical problems. No permanent procedural morbidity was observed. In all patients, a Raymond class 2 occlusion was obtained and five patients left the hospital with a good clinical status (mRS0 n = 3, mRS1 n = 1) or no new neurologic deficits (mRS4 n = 1). One patient with SAH III died due to severe vasospasms. Due to major recanalization during follow-up, retreatment was necessary or is planned in four cases; one asymptomatic intimal hyperplasia was observed 8 weeks after initial treatment.The waffle-cone technique may enhance the possibilities of the endovascular treatment of these complex aneurysms. Due to the high rate of recanalization requiring endovascular retreatment, stringent angiographic and clinical follow-up is warranted.

OBJECTIVE: Image-guidance systems are widely available for surgical planning and intraoperative navigation. Recently, three-dimensional volumetric image rendering technology that increasingly applies in navigation systems to assist neurosurgical planning, e.g., for cranial base approaches. However, there is no systematic clinical study available that focuses on the impact of this image-guidance technology on outcome parameters in suboccipital craniotomies. METHODS: A total of 200 patients with pathologies located in the cerebellopontine angle were reviewed, 100 of whom underwent volumetric neuronavigation and 100 of whom underwent treatment without intraoperative image guidance. This retrospective study analyzed the impact of image guidance on complication rates (venous sinus injury, venous air embolism, postoperative morbidity caused by venous air embolism) and operation times for the lateral suboccipital craniotomies performed with the patient in the semi-sitting position. RESULT: This study demonstrated a 4% incidence of injury to the transverse-sigmoid sinus complex in the image-guided group compared with a 15% incidence in the non-image-guided group. Venous air embolisms were detected in 8% of the image-guided patients and in 19% of the non-image-guided patients. These differences in terms of complication rates were significant for both venous sinus injury and venous air embolism (P < 0.05). There was no difference in postoperative morbidity secondary to venous air embolism between both groups. The mean time for craniotomy was 21 minutes in the image-guided group and 39 minutes in non-image-guided group (P = 0.036). CONCLUSION: Volumetric image guidance provides fast and reliable three-dimensional visualization of sinus anatomy in the posterior fossa, thereby significantly increasing speed and safety in lateral suboccipital approaches.

Objective It is impossible to precisely anticipate the crooked course of the transverse and sigmoid sinuses and their individual relationship to superficial landmarks such as the asterion during retrosigmoid approaches. This study was designed to evaluate this anatomical relationship with the help of a surgical planning system and to analyze the impact of these in vivo findings on trepanation placement in retrosigmoid craniotomies. Methods In a consecutive series of 123 patients with pathologies located in the cerebellopontine angle, 72 patients underwent surgical planning for retrosigmoid craniotomies based on 3D volumetric renderings of computed tomography venography. By opacity modulation of surfaces in 3D images the position of the asterion was assessed in relationship to the transverse–sigmoid sinus transition (TST) and compared to its intraoperative localization. We evaluated the impact of this additional information on trepanation placement. Results The spatial relationship of the asterion and the underlying TST complex could be identified and recorded in 66 out of 72 cases. In the remaining 6 cases the sutures were ossified and not visible in the 3D CT reconstructions. The asterion was located on top of the TST in 51 cases, above the TST in 4 cases, and below the TST in 11 cases. The location of the trepanation was modified in 27 cases due to the preoperative imaging findings with major and minor modifications in 10 and 17 cases, respectively. Conclusion Volume-rendered images provide reliable 3D visualization of complex and hidden anatomical structures in the posterior fossa and thereby increase the precision in retrosigmoid approaches.

Objectives In the management of patients with vestibular schwannoma it is essential to reliably assess tumor size. In respect to volumetric and linear measurements of these tumors we evaluated a) the inter-rater reliability, b) the intra-rater variability, c) the concordance of volume measurements derived from axial versus those from coronal MRI datasets, and d) the correlation of one-dimensional and volumetric measurements. Patients and methods We selected gadolinium-enhanced T1-weighted MRI datasets from 20 patients who had both axial and coronal datasets available with the same slice thickness in each of these orientations. Tumor volumes and diameters were independently determined by two investigators. Results The inter-rater reliability was determined based on the intra-class correlation coefficient, which was 0.998 for volumetric measurements and 0.950 for diameters. The relative smallest detectable difference between both raters was 21.2% for volumetric and 21.2% for linear measurements. Regarding the intra-rater variability we found a relative smallest detectable difference of 17.5% (rater 1) and 24.3% (rater 2) for volumetric measurements. The correlation between measurements on axial and those on coronal datasets was ρ = 0.999. In order to find a function that reliably predicts tumor volume from diameter, we fitted a series of equations based on linear and polynomial regression, with the highest regression coefficient being r2 = 0.79. Conclusion The longitudinal use of semi-automated volumetric measurements has the potential to accurately inform vestibular schwannoma disease management. We have quantified the reliability of this technique. A strict MRI protocol for follow-up investigations should be adhered to in order to minimize measuring errors.

OBJECTIVE C-reactive protein (CRP) is used as an indicator of inflammatory processes. However, its expression is unspecific and will increase after surgery. Without normative data on its regular course after craniotomy, postoperative infection can barely be detected or excluded. METHODS CRP was measured for 10 days in 46 patients who underwent elective craniotomy for microsurgery of intracranial tumors. RESULTS After craniotomy, CRP rapidly increased to reach a peak mean value of 32.43 +/- 38.02 mg/l (P < 0.001) on the second postoperative day. In 39 patients (85%), CRP reached its maximum level within the first 2 days. From Days 3 to 5 after surgery, mean CRP values constantly and significantly declined (P < 0.001) to arrive at a mean of 6.67 +/- 10.80 mg/l) on the fifth postoperative day. On Day 4, the mean CRP level returned to below one-third of the peak value (10.63 +/- 17.08 mg/l). On an individual basis, this was true for 34 patients (74%). During the period of initial increase of CRP until the second postoperative day, there was no significant correlation between CRP and erythrocyte sedimentation rate, body temperature, hemoglobin, hematocrit, red cell count, platelet count, and white cell count. CRP increase was more pronounced with intrinsic brain tumors and was not correlated to the degree of malignancy. CONCLUSION Because CRP can be considerably increased in patients for 4 days after regular intracranial surgery, its diagnostic value during this period is limited. Only prolonged elevation or a secondary increase may indicate an ongoing infection.

OBJECTIVE: Epidural electrical stimulation of the motor cortex is a promising treatment option in patients with intractable pain. Varying rates of success in long-term pain relief have been attributed to inaccurate positioning of the electrode array, partly because the sulcal landmarks are not directly visualized. We describe an integrated protocol for precise electrode placement, combining functional image guidance and intraoperative electrical stimulation in the awake patient. METHODS: Volumetric rendering of a three-dimensional (3-D) magnetic resonance data set was used to visualize the cortical surface and to superimpose functional magnetic resonance imaging data in six patients with refractory chronic pain. The intraoperative positioning of the quadripolar electrode array was monitored by functional 3-D image guidance. Continuous electrophysiological monitoring and clinical assessment of the motor effects complemented the procedure. RESULTS: Volumetrically rendered 3-D images were advantageous for the location of the burr hole over the perirolandic area by revealing individual cortical morphological features (e.g., the hand knob) and function at the same time. The exact position of the electrodes was verified reliably by cortical stimulation. No complications were observed throughout the procedures. CONCLUSION: The combination of 3-D functional neuronavigation, intraoperative electrical stimulation, and continuous motor output monitoring in awake patients provides optimal information for the identification of the appropriate somatotopic area of motor cortex. This combined imaging and stimulation approach for electrode positioning offers a safe and minimal invasive strategy for the treatment of intractable chronic pain in selected patients.

The objectives for microsurgical image-guidance in intracranial procedures are different from the entry-trajectory-target paradigm for stereotactic purposes. From a neurosurgical series of 125 patients with various intracranial pathologies having received surgery that was aided by image guidance, we have derived three basic principles for the successful application of neuronavigation in daily routine: (1) Less is more. Redundant anatomical information-basically all information that is unrelated to surgical landmarks in a particular case-should be omitted from the guiding images. (2) The approach and the surgical target should be visible in a single 3D guiding image. To this end, gradual tuning of the opacity of outer tissue layers in images is the method of choice to outline the in relation to the anatomy that needs to be dissected by the surgeon in order to arrive at the target. (3) All available information on functional tissue properties should be added to the guiding image. Preservation of function has become the single most important demand for neurosurgical procedures. Results of fMRI, DTI and other validated functional studies can readily be added to the structural image. Adhering to these principles may truly enhance the capacities of the surgeon who not only experiences a deja vue of the individual surgical anatomy when looking through the operating microscope but can also base his intra-operative decisions on invisible functional landmarks.

While bone invasion and hyperostosis are frequent phenomena in meningiomas, primary intra-osseous meningiomas are rare. With only 15 reported cases, the osteolytic form of primary intra-osseous meningiomas is most uncommon. Its occurrence in the skull base is an extra-ordinary exception. We have reviewed and categorized the pertinent literature on intra-osseus meningiomas with special emphasis on osteolytic tumours and discuss their clinical implications on the basis of a new case located in the petrous bone without contact with the meninges. It is concluded that due to their different clinical, radiological and pathological features, hyperostotic and osteolytic variants of intra-osseus meningiomas should be distinguished from tumours with soft tissue components and from en-plaque lesions.

The quality of leadership is usually assessed in terms of business performance, which is reflected in expenditure and revenue figures. Although cost efficiency becomes an ever more important factor in healthcare, financial revenue is not the only defining factor for quality of leadership in a business where the consequence of failure may be deadly in the true sense of the word. Moreover, since "health" and "well-being" are both complex issues involving a variety of psychological variables, customer satisfaction in this field is not always strictly related to the quality of the delivered care. This difficulty in the definition of an accomplished leader in healthcare may have added to the negligence in developing leadership in this field.

With the advent of image guidance systems, the intraoperative localization of intracranial lesions has become safer and damage to healthy tissue can be minimized. However, surgical planning and the operative approach are still largely based on triaxial images that have to be reconstructed mentally by the surgeon. We investigated the possibility to plan and to simulate surgical approaches to intracranial lesions based on three-dimensional (3D) volumetric image rendering capabilities of a new navigation system (CBYON). Fifty-seven patients with intracranial lesions underwent a preoperative MRI (1.5 or 3 T) after placement of adhesive fiducial markers. The cortical surface was reconstructed three-dimensionally based on a volumetric rendering algorithm with the CBYON guidance system. By modulation of the opacity of overlying structures, tumors could be visualized simultaneously with the cortical surface. Before surgery, a “fly-through” video option was used to simulate the surgical approach to the lesion. Real-time 3D image rendering of the cortical surface was possible in all patients. During planning, several possible approaches and patient positions could be compared within seconds. The new guidance system allowed for fast-and-easy assessment of the complex anatomical structure of gyri and sulci and the course of hidden vessels. The possibility to visualize the cortical surface in real-time 3D images that match the surgical situs represents a new quality in surgical planning and virtual simulation. This feature by far surpasses triaxial scan rendering and allows for instantaneous familiarization of individual intraoperative anatomy. In combination with virtual fly-through options volumetric three-dimensional real-time image rendering may become indispensable in neurosurgical planning, teaching and intraoperative navigation in approaches to intracranial lesions.

Long-term follow-up reports on chondroid lesions of the skull base are rarely presented in the literature. There are virtually no data on natural growth rates of these tumors based on MRI obtained over a period of 10 years or longer. We followed a patient who has had such a lesion for more than 12 years. A non-progressive, slight abducens palsy has been the only associated symptom so far. Even though the patient was operated on for an additional intracranial arterio-venous malformation, clinical features and chromosomal testing excluded Maffucci's syndrome. The MRI follow-up in this case provides an extraordinary perspective on the natural history of chondroid skull base tumors.

The cochlear nerve of adult Lewis rats was following microsurgical exposure in the cerebellopontine angle (CPA). The lesions completely interrupted the auditory nerve axons at the lesion site producing ipsilateral deafness in all animals. The rats were then treated with a recombinant Fab fragment of the antibody IN-1 against nerve growth inhibitory proteins for one to two weeks. An age-matched control group of rats was treated with unspecific mouse IgG antibody. Because the cochlear nerve lesions resulted in significant neuronal apoptosis of spiral ganglion cells, neurotrophin-3 (NT-3) was applied to the lesion site immediately post-injury in some rats. Electrophysiological studies were carried out by recording the brainstem auditory evoked potentials (BAEP) before and immediately after the lesion, and at regular intervals up to 2 months after injury. Cochlear nerve fibres were anterogradely traced by horseradish peroxidase (HRP) or biotinylated dextran amine (BDA) injected into the spiral ganglion. The results achieved in this study were consistent with the following conclusions: 1) transection of the adult rat cochlear nerve at the CPA results in functional deafness, disappearance of BAEP, apoptosis of parent axotomized neurons of the spiral ganglion, and interruption of labelled axons close to the lesion site; 2) NT-3 is able to partially rescue axotomized neurons of the spiral ganglion; 3) injured cochlear nerve fibres show a limited spontaneous sprouting and regrowth response which does not lead to BAEP recovery; 4) intrathecal treatment with IN-1 directed against myelin-associated neurite growth inhibitory proteins promotes significant elongation of the injured fibres; and 5) the regenerating fibres seem to navigate to correct targets, and be able to establish synaptic connections for functional recovery as depicted by BAEP examinations.

Object. A new generation of penetrating electrodes for auditory brainstem implants is on the verge of being introduced into clinical practice. This study was designed to compare electrically evoked auditory brainstem responses (EABRs) to stimulation of the cochlear nucleus (CN) by microsurgically implanted surface electrodes and insertion electrodes (INSELs) with stimulation areas of identical size. Methods. Via a lateral suboccipital approach, arrays of surface and penetrating microelectrodes with geometric stimulation areas measuring 4417 µm2 (diameter 75 µm) were placed over and inserted into the CN in 10 adult cats. After recording the auditory brainstem response (ABR) at the mastoid process, the CN, and the level of the inferior colliculus, EABRs to stimulation of the CN were recorded using biphasic, charge-balanced stimuli with phase durations of 80 µsec, 160 µsec, and 240 µsec at a repetition rate of 22.3 Hz. Waveform, threshold, maximum amplitude, and the dynamic range of the responses were compared for surface and penetrating electrodes. The EABR waveforms that appeared for both types of stimulation resembled each other closely. The mean impedance was slightly lower (30 ± 3.4 kΩ compared with 31.7 ± 4.5 kΩ, at 10 kHz), but the mean EABR threshold was significantly higher (51.8 µA compared with 40.5 µA, t = 3.5, p = 0.002) for surface electrode arrays as opposed to penetrating electrode arrays. Due to lower saturation levels of the INSEL array, dynamic ranges were almost identical between the two types of stimulation. Sectioning of the eighth cranial nerve did not abolish EABRs. Conclusions. Microsurgical insertion of electrodes into the CN complex may be guided and monitored using techniques similar to those applied for implantation of surface electrodes. Lower thresholds and almost equivalent dynamic ranges indicate that a more direct access to secondary auditory neurons is achieved using penetrating electrodes.

Intracranial fibromuscular dysplasia (FMD) is a vascular disease of unknown origin occurring predominantly in young women. The internal carotid artery is most often involved, but other cerebral arteries may also be affected. We report the case of a young woman presenting with an unusual angiographic appearance of intracranial FMD of the internal carotid artery (ICA) that could not be categorized into any type of the Osborn–Anderson classification. During follow up the patient presented with an intracerebral and subarachnoid hemorrhage. Repeated angiography revealed multiple aneurysms in the pathologic segment of the vessel. The patient underwent surgical treatment with clipping of the aneurysms, wrapping of the pathologic segment of the ICA and biopsy of the superficial temporal artery. Histopathological sections revealed FMD of the intimal type. α 1 -antitrypsin blood levels were normal. Cases of intracranial FMD previously reported in the literature are reviewed and various aspects of this rare disease are discussed.

Object. Both C-reactive protein (CRP) level and erythrocyte sedimentation rate (ESR) were measured prospectively in 51 cases in which uncomplicated cervical anterior fusion was performed. The object of the authors was to quantify the differences in the responses of these parameters recorded in the immediate postoperative period and to determine factors influencing their course. Methods. Nineteen one-level, 23 two-level, and nine three-level procedures for disc herniation and degenerative disease of the cervical spine were performed in 22 female and 29 male patients (mean age 49.2 years). Blood samples were obtained 1 day before as well as on 10 consecutive days and 3 months following anterior cervical fusion. Serum CRP level was measured using a fluorescence polarization immunoassay and ESR was determined from the same samples. Operative time, the number of blood transfusions, and drugs administered in the postoperative period were recorded. In addition, hemoglobin, hematocrit, red blood cell count, platelet count, white cell count, and axillary body temperature were checked daily. Conclusions. Monitoring of CRP level is superior to that of ESR for early detection of infections after cervical spine surgery. Although CRP was not related to any of the factors that have been proposed to explain its peak value variance in previous studies, individual acute-phase protein metabolism response to tissue affection appears to be a more decisive element in this respect.

✓ Superior oblique myokymia (SOM) is a rare eye movement disorder presenting as uniocular rotatory microtremor due to intermittent contractions of the superior oblique muscle. Medical treatment usually fails to provide long-term benefit for the patient and has considerable side effects. Surgical alternatives including tenotomy or partial tenectomy of the superior oblique tendon often result in incomplete resolution of the visual symptoms. The authors report a patient who experienced immediate cessation of disabling SOM following microvascular decompression of the fourth nerve at the root exit zone. Temporary double vision at downgaze resolved 5 months after surgery. There was no recurrence of oscillopsia during a follow-up of 22 months to date. From this single observation it appears likely that vascular compression of the trochlear nerve could be a significant pathophysiological factor contributing to SOM. In the hands of an experienced surgeon, microvascular decompression at the brainstem exit zone of this nerve may evolve as the method of choice for selected cases of disabling SOM.

Im Rahmen der Abklarung einer progredienten zervikalen Myelopathie und Radikulopathie wurde bei einem 26 jahrigen Patienten kernspintomographisch eine in T1- und T2-Wichtung hyperintense zervikale, intramedullare Raumforderung mit masiger perifokaler Kontrastmittelaufnahme nachgewiesen. Nach intensiver histologischer Aufarbeitung des Operationspraparats wurden innerhalb eines chronischen Abszesses parasitare Strukturen wie bei einer Neurozystizerkose nachgewiesen. In der Folge wurden ebenfalls kernspintomographisch multiple kleinere, thorakale Herde und eine grose inhomogene Raumforderung im Bereich des Conus medullaris diagnostiziert. Ein spezifischer IHA fur Antikorper gegen Cysticercus cellulosae im Serum erwies sich als schwach positiv bei negativem Liquorbefund. Anamnestisch ergaben sich retrospektiv ebenfalls Anhaltspunkte fur das Vorliegen einer abgelaufenen Neurozystizerkose. Auch ein 20 Jahre zuruckliegender Aufenthalt in Guatemala war in dieser Hinsicht verdachtig. Bemerkenswert ist, neben der hier zum ersten Mal in Mitteicuropa beobachteten und auch weltweit sehr seltenen intramedullaren Form der spinalen Neurozystizerkose, das lange Zeitintervall zwischen dern Aufenthalt in einem endemischen Gebiet und dem Auftreten einer rasch progredienten Symptomatik. Radiologische, histologische und serologische Befunde weisen darauf hin, das es sich dabei um eine spate, unspezifische Fremdkorperreaktion gegen absterbende oder degenerierte parasitare Bestandteile handeln konnte. Die planare Szintigraphie mit markierten Leukozyten kann zur Aufdeckung aktiv-entzundlicher Stadien der Zystizerkose und zur Differentialdiagnose beitragen.

We report the case of a 44-year-old patient with a MRI scan showing a newly developed cavernoma after two highly calcified lesions had been excised surgically. Six other cavernous malformations had been followed by MR imaging over a 2-year period. The coexistence of the two extremes of cavernous malformations in terms of lesions development—de novo and ossified lesions—has not been reported previously and has implications for both the follow-up and the natural history of these malformations. The potential for developing new cavernous malformations persists and does not seem to be related to the evolutional stage of pre-existing lesions. It is suggested that these patients need to be followed up by MRI on a regular basis.