Cauda equina neuroendocrine tumor: a report of three cases and review of the literature with focus on differential diagnosis and postoperative management.

INTRODUCTION: Cauda equina neuroendocrine tumors (CENETs), previously described as cauda equina paragangliomas (PGLs) are rare and well-vascularized benign entities which can be often misdiagnosed with other intradural tumors more common in this anatomical site, such as ependymomas and neurinomas. We describe three cases of CENETs observed at our institution with particular focus on differential diagnosis and postoperative management. Since the lack of guidelines, we performed a literature review to identify factors that can predict recurrence and influence postoperative decision making. CASE REPORT AND LITERATURE REVIEW: We report on three patients, two of them presenting with a clinical history of lower back pain and sciatica. In all cases magnetic resonance imaging (MRI) of the lumbosacral spine with and without Gd-DTPA revealed an intradural lesion with strong contrast enhancement, first described as atypical ependymoma or schwannoma. A complete tumor resection was achieved in all cases, the histopathological diagnosis classified the tumors as CENETs. In our literature review, a total of 688 articles were screened and 162 patients were included. Patients demographic data, clinical symptoms, resection and recurrence were recorded. DISCUSSION: Differential diagnosis between CENETs and other more common tumors affecting cauda equina region, such as ependymomas or schwannomas (neurinomas), is still very challenging. Due to the lack of specific clinical or radiological characteristics, a correct preoperative diagnosis is almost impossible. With this paper we want to point out that CENETs must be considered in the differential diagnosis, most of all in case of entities with atypical radiological features. According to the literature, tumor recurrence after gross total resection is unlikely, while a long-term follow-up is recommended in case of subtotal resection or local aggressive behavior.

[Update on diagnostics and microsurgical treatment of vestibular schwannoma]. / Vestibularisschwannome ­ ein Update zu Krankheitsbild und mikrochirurgischer Behandlung.

Vestibular schwannomas are primary benign tumors of the cerebellopontine angle originating either from the superior or the inferior vestibular nerve. Hearing deterioration is the leading symptom, which is why the widespread name for this tumor is acoustic neuroma. Due to the widespread availability of magnetic resonance imaging (MRI), the diagnosis of vestibular schwannoma is frequently made in an early stage of the disease. In these cases a wait and scan policy is recommended. If the tumor grows, the therapeutic options are stereotactic radiotherapy or microsurgical tumor operation. Young patient age, functional hearing ability, persistent dizziness, cystic tumor consistence and large space-occupying tumor size are in favor of surgery via the retrosigmoid, transmeatal approach. In experienced hands excellent results in terms of functional preservation of the facial nerve and the cochlear nerve and radical tumor resection can be obtained.

Depiction of the Superior Petrosal Vein Complex by 3D Contrast-Enhanced MR Angiography.

BACKGROUND AND PURPOSE: Intraoperative obliteration of the superior petrosal vein complex has a relevant risk of postoperative complications. A large venous diameter and the absence of anastomoses have been previously suggested as possible risk factors. 3D contrast-enhanced MRA was evaluated for the identification of superior petrosal vein anatomy. MATERIALS AND METHODS: Twenty-five patients (10 men; age, 20-77 years) with a 3D-MRA (voxel size, 0.4 × 0.4 × 0.5 mm3) at 3T, including the posterior fossa, were retrospectively identified. Image evaluation was performed independently by 2 neuroradiologists with respect to overall image quality and the presence, location, size, tributaries, and anastomotic veins of the superior petrosal vein complex. Additionally, 8 neurosurgical cases with intraoperative validation of the venous anatomy were examined. RESULTS: All studies were of diagnostic image quality. Interobserver agreement was excellent for image-quality measurements (r = 0.751-0.982) and good for measured vessel size (r = 0.563-0.828). A total of 83 superior petrosal veins were identified. The distribution of drainage locations and identification of tributaries and anastomotic veins were consistent with previous anatomic studies. The results showed that 4.8% of superior petrosal veins had a diameter of >2 mm and lacked a visible anastomosis. All surgical cases showed excellent agreement between the MRA and the intraoperative observations. CONCLUSIONS: 3D-MRA with high resolution is appropriate for analyzing the size, course, tributaries, and anastomoses of the superior petrosal vein. A total of 4.8% of the identified superior petrosal veins had to be classified as potential high-risk veins. The measurements correlated with the intraoperative findings.

Posterior fossa meningioma with invasion of the internal acoustic canal.

BACKGROUND: To evaluate the significance for outcome of meningioma invasion into the internal auditory canal (IAC) in posterior fossa meningiomas. METHODS: From April 2005 to September 2015, 174 posterior fossa meningiomas have been surgically treated in our Institution. Careful analysis of preoperative MRI depicted in 63 cases (36%) meningioma invasion into the IAC. A retrospective analysis was done of clinical and radiological presentation, surgical findings, outcome, and relevant prognostic factors in order to stratify the risk of complication and evaluate the surgical outcome. RESULTS: Gross total resection was achieved in 67% of patients. There was no mortality. CSF leak occurred in 5%. Postoperative moderately severe (HB 4) and severe dysfunction (HB 5) of the facial nerve was observed in 5% of patients. In 17 patients (27%), IAC was opened. Deterioration of facial function occurred in 24% of patients, hearing loss in 12%, and CSF leak in 6%. In 46 patients (73%), IAC was not opened. Deterioration of facial function occurred in 43% of patients, hearing loss in 13%, and CSF leak in 4%. Opening the IAC, a GTR was achieved in 82% while, without opening, in 61% of patients. CONCLUSIONS: Meningiomas of the posterior fossa may in one-third of the cases invade the IAC. Opening of the IAC in these cases was a crucial step for increasing the GTR. Despite the minimal increased risk of transient CSF leak, IAC opening was not associated with an increased risk of facial palsy or hearing loss in comparison to non-opening the IAC.

Maximizing the extent of resection and survival benefit of patients in glioblastoma surgery: high-field iMRI versus conventional and 5-ALA-assisted surgery.

AIMS: A safe total resection followed by adjuvant chemoradiotherapy should be the primary goal in the treatment of glioblastomas (GBMs) to enable patients the longest survival possible. 5-aminolevulinic acid (5-ALA)- and intraoperative MRI (iMRI)-assisted surgery, have been shown in prospective randomized trials to significantly improve the extent of resection (EOR) and subsequently survival of patients with GBMs. No direct comparison of surgical results between both techniques has been published to date. We analyzed the additional value of iMRI in glioblastoma surgery compared to conventional surgery with and without 5-ALA. METHODS: Residual tumor volumes, clinical parameters and 6-month progression-free survival (6M-PFS) rates after GBM resection were analyzed retrospectively for 117 patients after conventional, 5-ALA and iMRI-assisted surgery. RESULTS: Mean residual tumor volume (range) after iMRI-assisted surgery [0.5 (0.0-4.7) cm(3)] was significantly smaller compared to the residual tumor volume after 5-ALA-guided surgery [1.9 (0.0-13.2) cm(3); p = .022], which again was significantly smaller than in conventional white-light surgery [4.7 (0.0-30.6) cm(3); p = .007]. Total resections were significantly more common in iMRI- (74%) than in 5-ALA-assisted (46%, p = .05) or white-light surgery (13%, p = .03). Improvement of the EOR by using iMRI was safely achievable as peri- and postoperative morbidities were comparable between cohorts. Total resections increased 6M-PFS from 32% to 45%. CONCLUSIONS: Analysis of residual tumor volumes, total resections and neurological outcomes demonstrate that iMRI may be significantly superior to 5-ALA and white-light surgery for glioblastomas at comparable peri- and postoperative morbidities. Longer 6M-PFS was observed in patients with total resections.

[Modern surgery of meningiomas affecting anterior visual pathways]. / Moderne Meningeomchirurgie im Bereich der vorderen Sehbahn.

Meningiomas are the most common form of primary intracranial tumors. If the anterior visual pathways are affected clinical visual compromise, visual field defects, oculomotor nerve disturbances or propotosis are predominant. Meningiomas of the anterior visual pathway remain therapeutically challenging due to the direct anatomical relationship to the circulus arteriosus cerebri, the cavernous sinus and cranial nerves. The therapy of choice is microsurgical resection. In many cases a curative approach can be achieved with modern surgical techniques and simultaneously maintaining patient quality of life. Problematic are cases in which resection would be associated with the risk of clinical impairment and in these cases radiotherapy is an important therapeutic option. In cases involving complex invasiveness an interdisciplinary treatment to control local clinical symptoms is favored.

Pituicytoma in a patient with Cushing's disease: case report and review of the literature.

Pituicytoma is an exceptionally rare low-grade glioma (WHO grade I) of the neurohypophysis and infundibulum. We are reporting the case of a 48-year-old man who presented with severe Cushing's syndrome. Endocrinological evaluation unequivocally confirmed pituitary-dependent Cushing's syndrome (=Cushing's disease). Cranial MR-imaging displayed a conspicuous area in the dorsal and basal pituitary gland and a minimal bulging of the pituitary gland paramedian of the pituitary stalk on the right side. Transsphenoidal inspection revealed a small tumor in the basal and dorsal pituitary gland. Surprisingly, the definite postoperative histopathological diagnosis of the removed tumor was pituicytoma and not pituitary adenoma. Hence, the microadenoma responsible for Cushing's disease was not yet removed and persistent hypercortisolism necessitated transsphenoidal re-operation. During re-operation, hemihypophysectomy was performed on the right side. The non-tumorous specimen of the adeno-hypophysis showed signs of Crooke's hyalinization consistent with Cushing's disease. Undetectable postoperative ACTH- and cortisol levels provided clear evidence that the underlying ACTH-source was successfully removed during re-operation. Coincidence of pituicytoma and pituitary-dependent Cushing's disease has not previously been reported.

Use of STAT1 inhibitors in the treatment of brain I/R injury and neurodegenerative diseases.

In the etiology of brain injury associated to ischemia/reperfusion (I/R) and neurodegenerative diseases, a critical involvement of excessive activation of signal transducer and activator of transcription 1 (STAT1) and successive induction of iNOS expression has widely been evidenced. Any compound capable to down-regulate STAT1 activation seems to represent a new, promising anti-inflammatory drug. Among plant compounds, only a few have shown to possess anti-STAT1 activity. Among them, epigallocatechin-3-gallate (EGCG), the main polyphenol present in green tea leaves, efficiently protects heart from I/R injury and this action is strictly correlated to its anti-STAT1 property. Hyperforin, the non-polyphenolic compound present in St. John's wort, attenuates β-cell death induced by interferon-γ (IFN-γ) by strongly down-regulating STAT1 activation. STAT1, therefore, seems to represent a new molecular target of the protective treatment also against brain injury associated to a number of brain pathologies. Either understanding the molecular mechanism of anti-STAT1 action of these compounds or identification of other anti-STAT1 compounds are urged.

Balancing the shortcomings of microscope and endoscope: endoscope-assisted technique in microsurgical removal of recurrent epidermoid cysts in the posterior fossa.

BACKGROUND: We report about endoscope-assisted surgery of epidermoid cysts in the posterior fossa focusing on the application of neuro-endoscopy and the clinical outcome in cases of recurrent epidermoid cysts. MATERIAL AND METHODS: 25 consecutively operated patients with an epidermoid cyst in the posterior fossa were retrospectively analysed. Surgeries were performed both with an operating microscope (OPMI Pentero or NC 4, Zeiss Company, Oberkochen, Germany) and endoscopic equipment (4 mm rigid endoscopes with 30° and 70° optics; Karl Storz Company, Tuttlingen, Germany) under continuous intraoperative monitoring. Surgical reports and DVD-recordings were evaluated for identification of adhesion areas and surgical details. RESULTS: 7 (28%) of the 25 patients were recurrences of previously operated epidermoid cysts. Mean time to recurrence was 17 years (8-22 years). In 5 cases the endoscope was used as an adjunctive tool for inspection/endoscope-assisted removal of remnants. The effective time of use of the endoscope was limited to the end stage of the procedure, but was very effective. CONCLUSION: In a modern operative setting and with the necessary surgical experience recurrent epidermoid cysts may be removed with excellent clinical results. The combined use of microscope and endoscope offers relevant advantages in demanding anatomic situations.

Broadening horizons of neuroendoscopy with a variable-view rigid endoscope: an anatomical study.

AIM: To test the versatility and usefulness of a prototype rigid endoscope with a continuously variable-view-angle tip (Endochamaeleon, Karl Storz, Tuttlingen, Germany) with regard to field of vision and applicability for endoscopic assisted neurosurgery. METHODS: In five formaldehyde fixed specimens frontolateral and retrosigmoid approaches were prepared on both sides and five target positions of the endoscopes tip were defined. A rigid 4mm endoscope, which offers in one plane a viewing range of approximately -10 degrees to +120 degrees by turning a proximal knob coupled to fine distal optomechanics was compared to 0 degrees , 45 degrees , and 70 degrees rigid endoscopes. The visualizable neuroanatomical structures were assessed for each position, endoscope angle, and plane of view as well as the over-all visibility of neuroanatomical structures and the time factor. RESULTS: 1905 recorded images of 1800 different views were analyzed. The EC offers a variable angle of view in one plane without need to change the endoscope position. This feature is well suited for inspection of functionally delicate areas at the skull base. The maximum number of visible structures for each position was only seen with the EC. Endoscopic exploration was significantly less time consuming with the EC than with the other endoscopes. CONCLUSION: The EC provided superior usability and visualization potential compared to standard rigid endoscopes with fixed angulation. It combines the ergonomic and safety advantage of not having to insert endoscopes with different angles with the opportunity to "scan" the surgical field with a variable angle of 0 degrees -120 degrees within one plane of view.

Venous complications following petrosal vein sectioning in surgery of petrous apex meningiomas.

OBJECTIVE: Meningiomas involving the petrous apex regularly show a close relationship with the superior petrosal vein which is sometimes obliterated during surgery due to its proximity to the tumour. However, there is no study available so far focusing on the frequency of postoperative venous congestion related complications following petrosal vein obliteration as well as on pre- and intraoperative findings related to them. METHODS: Fifty-nine patients with meningiomas involving the petrous apex were analyzed concerning the intraoperative preservation or sacrifice of the petrosal vein and postoperative complications related to venous occlusion. RESULTS: When a petrosal vein was occluded, in 9 of 30 cases venous-related complications occurred with a minor venous-congestion phenomenon in seven cases and major complications in two cases. When the petrosal vein complex was preserved, there were no similar complications. CONCLUSION: Preservation of the petrosal venous complex, especially of large caliber veins, should be attempted whenever possible to increase the safety of surgery. In cases of petrosal vein obliteration, effective brainstem decompression following tumour removal is essential to minimizing the risk of cerebellar congestion.

Petrosal vein occlusion in cerebello-pontine angle tumour surgery: an anatomical study of alternative draining pathways.

OBJECTIVE: The present anatomic study investigates alternative draining pathways of the petrosal vein territory, which allow compensation in case of surgical sacrifice. METHODS: In eight (four formaldehyde fixed and four alcohol fixed) specimens the petrosal vein complex has been dissected and studied. Three heads have been selectively injected via the superior petrous sinus with colored silicon in two different colors. Thereafter the posterior fossa content was removed epidurally from the skull and further fixed in 4% formaldehyde. The nervous and vascular structures were dissected under microscopic control, measured and photographed. 3D-photographs were elaborated. RESULTS: The petrosal vein was present in all cases and joined the superior petrous sinus always lateral to the trigeminal nerve as a single trunk. In the selectively injected specimens no passage of the colored silicon mixture to the contralateral venous brainstem territory could be discerned. However, the ipsilateral anastomoses to the deep supratentorial venous system--peduncular, anterolateral pontomesencephalic, lateral mesencephalic veins, and the tectal veins in connection with the pontotrigeminal vein--filled in all cases. CONCLUSION: Although the present anatomical model does not reflect physiological aspects of vascular dynamics, we document an apparently compensatory venous blood drainage occurring via anastomotic pathways directed to the ipsilateral supratentorial venous system. These findings represent an interesting aspect for preoperative image-guided planning in cerebello-pontine angle surgery.

The retrosigmoid intradural suprameatal approach to posterior cavernous sinus: microsurgical anatomy.

OBJECTIVE: The retrosigmoid intradural suprameatal approach includes the standard retrosigmoid suboccipital route with drilling of the petrous bone above and anterior of the internal auditory meatus, allowing for exposure of the trigeminal nerve within the Meckel's cave and of the middle fossa. In this study, the authors analyzed the potential use of an extended variation of the suprameatal route to approach the posterior cavernous sinus for microsurgery of, e.g., petroclival meningiomas and trigeminal schwannomas. METHODS: The microsurgical anatomy of the retrosigmoid suprameatal approach was examined by using 10 adult cadaveric specimens (20 sides), using 3-40x magnification. The exposure to the posterior cavernous sinus provided by this approach was focused. RESULTS: After drilling the suprameatal tubercle toward the petrous apex, the Meckel's cave was exposed. The trochlear nerve was the landmark for opening the cavernous sinus by this approach. The dura located medially to the entry point of the trochlear nerve into the tentorium was resected, allowing exposure of the intracavernous carotid artery with its meningohypophyseal trunk. CONCLUSION: The extended retrosigmoid intradural suprameatal approach allows exposure of the posterior cavernous sinus and may be used to remove lesions of the posterior fossa extending into the Meckel's cave and into the cavernous sinus.

Tuberculum sellae meningioma symptomatic during pregnancy: pathophysiological considerations.

A 31 year old woman in her second pregnancy presented in the 31st (+4) week of gestation with progressive visual impairment of the right eye. Magnetic resonance imaging (MRI) demonstrated a tuberculum sellae meningioma that was displaced upward by a markedly enlarged pituitary gland. Neuro-ophthalmological follow-up examinations showed a progressive decrease of visual acuity and right temporal field loss. Therefore, a caesarean section was performed in the 34th (+8) week. The meningioma was removed three days after childbirth via a right-sided pterional approach. Post-operatively, visual function was completely restored. Immunohistochemical examination showed positive staining for progesterone receptors (PR) in approximately 50% of tumour cells. Enlargement of the pituitary gland during late pregnancy in conjunction with a preexisting tuberculum sellae meningioma is the most likely pathophysiological factor responsible for visual loss. Enlargement of the PR-positive meningioma in the hormonal milieu of pregnancy might have contributed additionally to visual loss.

Carotid endarterectomy: comparing anesthesia in awakened and intubated patients with general anesthesia.

AIM: The purpose of this study was to determine utility and efficacy of anesthesia with remifentanil in awakened and intubated patients in comparison with general anesthesia and routine shunting. METHODS: Hundred patients were randomized for general anesthesia (group A) or anesthesia with remifentanil (group B). The two groups were compared in terms of postoperative outcome, neurological complications, arterial pressure during intervention and in during the following 36 hours. Group B patients answered a proposed questionnaire about intraoperative and postoperative degree of comfort, fear, pain and discomfort for the orotracheal tube. RESULTS: The two groups differed significantly only for age (group B>A); 10% of patients was not considered fit for the anesthesia with remifentanil (initial experience only). The two groups did not differ in terms of central neurologic complications (0%), general complications or technical problems in terms of intra-operative arterial pressure problems (the anesthesia with remifentanil caused less hypertensive problems (P>0,19) and (not technique-dependent) peripheral neurologic deficits. All patients accepted the method and did not report fear or discomfort. Only 3 patients (6.6%) described light pain during the intervention. In 2 cases (4.4%) the surgeon complained about the restlessness of the patient; this did not cause a change in procedure. CONCLUSIONS: General anesthesia with remifentanil produces an association between the advantage of locoregional anesthesia and those of general anesthesia, probably lowering the risk for the patients.

Management of skull based meningiomas in the elderly patient.

BACKGROUND: The demographic evolution of Western society together with availability of modern imaging techniques leads to an increasing diagnosis of meningioma patients over 70 years of age. This raises the question of appropriate management of this histologically benign tumour in a geriatric population. DESIGN: Forty-three patients aged over 70 years were analyzed and matched in a retrospective study with a younger group of 89 patients according to tumour size, histology, symptoms, recurrence and presence of neurofibromatosis II. RESULTS: Changes in postoperative Karnofsky scores were not statistically different between the two age groups. Neurological outcome was worse among the younger group (12% vs. 7% deterioration). Regarding surgical complications we noted only a statistically significant higher infection rate in the geriatric age group. There was no peri-operative mortality. CONCLUSIONS: Age alone is not a criterion to deny a priori skull base surgery, since well selected geriatric patients may benefit from a meningioma operation that may enhance future quality of life.

Endoscope-assisted retrosigmoid intradural suprameatal approach to the middle fossa: anatomical and surgical considerations.

INTRODUCTION: Lesions involving the posterior and middle fossa may be reached by several surgical approaches depending mostly on tumors' location and characteristics. The retrosigmoid intradural suprameatal approach has been used to remove tumors of the posterior fossa extending into Meckel's cave and the middle fossa. With large tumors, this approach may allow exposure of the oculomotor and optic nerves, the supraclinoid internal carotid and communicating posterior arteries. METHODS: Three formaldehyde-fixed specimens have been prepared on both sides using the conventional retrosigmoidal-suprameatal approach. The entire endoscopic preparations have been documented via a digital recording system, using a 5mm endoscope with a 25 degrees perspective. The authors describe the anatomical corridor and technique of the endoscope-assisted retrosigmoid intradural suprameatal approach to lesions that are located predominantly within the posterior fossa and supratentorial extension into Meckel's cave, sellar and parasellar region. CONCLUSIONS: The endoscope-assisted suprameatal approach provides exposure of the antero-medial middle fossa even in cases of skull base lesions that have not caused significant displacement of neurovascular structures.