The Asterion-to-Transverse Process of the Atlas Line as a Surgical Landmark.

Introduction Proposed landmarks to predict the anatomical location and trajectory of the sigmoid sinus have varying degrees of reliability. Even with neuronavigation technology, landmarks are crucial in planning and performing complex approaches to the posterolateral skull base. By combining two major dependable structures-the asterion (A) and transverse process of the atlas (TPC1)-we investigate the A-TPC1 line in relation to the sigmoid sinus and in partitioning surgical approaches to the region. Methods We dissected six cadaveric heads (12 sides) to expose the posterolateral skull base, including the mastoid and suboccipital bone, TPC1 and suboccipital triangle, distal jugular vein and internal carotid artery, and lower cranial nerves in the distal cervical region. We inspected the A-TPC1 line before and after drilling the mastoid and occipital bones and studied the relationship of the sigmoid sinus trajectory and major muscular elements related to the line. We retrospectively reviewed 31 head and neck computed tomography (CT) angiograms (62 total sides), excluding posterior fossa or cervical pathologies. Bone and vessels were reconstructed using three-dimensional segmentation software. We measured the distance between the A-TPC1 line and sigmoid sinus at different levels: posterior digastric point (DP), and maximal distances above and below the digastric notch. Results A-TPC1 length averaged 65 mm and was posterior to the sigmoid sinus in all cadaver specimens, coming closest at the level of the DP. Using the transverse-asterion line as a rostrocaudal division and skull base as a horizontal plane, we divided the major surgical approaches into four quadrants: distal cervical/extreme lateral and jugular foramen (anteroinferior), presigmoid/petrosal (anterosuperior), retrosigmoid/suboccipital (posterosuperior), and far lateral/foramen magnum regions (posteroinferior). Radiographically, the A-TPC1 line was also posterior to the sigmoid sinus in all sides and came closest to the sinus at the level of DP (mean, 7 mm posterior; range, 0-18.7 mm). The maximal distance above the DP had a mean of 10.1 mm (range, 3.6-19.5 mm) and below the DP 5.2 mm (range, 0-20.7 mm). Conclusion The A-TPC1 line is a helpful landmark reliably found posterior to the sigmoid sinus in cadaveric specimens and radiographic CT scans. It can corroborate the accuracy of neuronavigation, assist in minimizing the risk of sigmoid sinus injury, and is a useful tool in planning surgical approaches to the posterolateral skull base, both preoperatively and intraoperatively.

Intraoperative Magnetic Resonance Imaging-Guided Glioma Resections in Awake or Asleep Settings and Feasibility in the Context of a Public Health System.

BACKGROUND: Despite the most recent surgical aids and tools, surgical removal of infiltrating brain tumors remains a challenge. Unclear margins, edematous areas, and infiltrative behavior are the main causes for failing gross total removals. Also, excessive resection of peri-tumoral tissue often carries risks of damaging the nearby functioning cortical and subcortical structures with an unacceptable decrease in patient's quality of life and postoperative functional status, and the risk of making patients not eligible to adjuvant treatments. Awake surgery and intraoperative magnetic resonance imaging (ioMRI) are among the most effective aids in preventing damage to functional brain while maximizing the extent of resection. METHODS: We present our series of 46 patients operated on at Southmead Hospital (North Bristol NHS Trust) in between July 2014 and February 2017 using ioMRI plus or minus awake surgery. Setting, patient features, indications, type and size of tumors, surgical times, extent of resection, morbidity, and survival are analyzed and discussed. RESULTS: Overall, ioMRI check led to a +43% resections in Group 1 and +58% in Group 2. In grade 2 tumors, GTR was 46% in Group 1 and 55% in Group 2 (41% in control group). In grade 3 tumors, GTR was 57% in Group 1 and 66% in Group 2 (30% in control group). In Grade 4 tumors, GTR was 63% in Group 1, 66% in Group 2 (36% in control group). In terms of theatre occupation, the use of ioMRI added 1/2 operative session; the addition of awake surgery implied the use of another 1/2 operative session. Morbidity did not differ among the groups, with low incidence of permanent post-operative deficits (<5%). Group 2 OS was statistically longer when compared to the control group. CONCLUSIONS: Using ioMRI together with awake surgery is demanding for the anesthetic team, staff nurses, and for the patient. Nevertheless, low morbidity, greater total resections rates, and longer survival suggest its use is effective in making more approachable gliomas of all grades that we would consider "complex" due to their intrinsic features or locations.

Proposal of Standardization of Closure Techniques After Endoscopic Pituitary and Skull Base Surgery Based on Postoperative Cerebrospinal Fluid Leak Risk Classification.

Postoperative cerebrospinal fluid (CSF) leak still represents the main limitation of endonasal endoscopic surgery. The aim of the study is to classify the risk of postoperative leak and to propose a decision-making protocol to be applied in the preoperative phase based on radiological data and on intraoperative findings to obtain the best closure.One hundred fifty-two patients were treated in our institution; these patients were divided into 2 groups because from January 2013 the closure technique was standardized adopting a preoperative decision-making protocol. The Postoperative CSF leak Risk Classification (PCRC) was estimated taking into account the size of the lesion, the extent of the osteodural defect, and the presence of intraoperative CSF leak (iCSF-L). The closure techniques were classified into 3 types according to PCRC estimation (A, B, and C).The incidence of the use of a nasoseptal flap is significantly increased in the second group 80.3% versus 19.8% of the first group and the difference was statistically significant P < 0.0001. The incidence of postoperative CSF leak (pCSF-L) in the first group was 9.3%. The incidence of postoperative pCSF-L in the second group was 1.5%. An analysis of the pCSF-L rate in the 2 groups showed a statistically significant difference P = 0.04.The type of closure programmed was effective in almost all patients, allowing to avoid the possibility of a CSF leak. Our protocol showed a significant total reduction in the incidence of CSF leak, but especially in that subgroup of patients where a leak is usually unexpected.

Intradural Extramedullary Primary Ependymoma of the Craniocervical Junction Combined with C1 Partial Agenesis: Case Report and Review of the Literature.

BACKGROUND: Intramedullary ependymomas represent 40%-60% of spinal cord tumors in adults and can be located along the entire spinal cord. Intradural extramedullary (IDEM) ependymomas are very rare with the exception of tumors located at the filum terminale or conus medullaris, with histologic features of myxopapillary ependymomas (World Health Organization grade I). CASE DESCRIPTION: We present the case of a 42-year-old woman with an IDEM ependymoma of the craniocervical junction who experienced neck pain for 5 months. Magnetic resonance imaging of the cervical spine and craniocervical junction showed a large IDEM solid-cystic lesion with anterolateral junction spinal cord compression. A preoperative computed tomography scan did not show any calcified lesion, although a partial agenesis of the C1 posterior arch was observed. During surgery, a well-encapsulated IDEM tumor without dural attachment or medullary infiltration was found, and a total en bloc excision was performed. Histologic examination revealed a grade II ependymoma. The patient had an excellent clinical recovery, with no recurrence after 2 years of follow-up. CONCLUSIONS: To the best of our knowledge, no other cases of craniocervical junction ependymomas with vertebral bone abnormalities are described in the literature. This association supports the hypothesis that these lesions may originate from the extrusion of ependymal cells before neural tube closure. Differential diagnosis should include other extramedullary tumors that are more frequent in this region, such as meningioma, schwannoma, or dermoid tumor.

Two cystic cavernous angiomas after radiotherapy for atypical meningioma in adult woman : case report and literature review.

A correlation between radiation therapy and cavernoma has been suspected since 1994. Since then, only a few cases of radio-induced cavernomas have been reported in the literature (85 patients). Most of them were children, and the most frequent original tumour had been medulloblastoma. The authors report a case of two cystic cavernous angiomas after radiation therapy for atypical meningioma in adult woman. This is the first case of cavernous angioma after radiotherapy for low grade meningioma. A 39-year-old, Latin american woman was operated on for a frontal atypical meningioma with intradiploic component and adjuvant radiotherapy was delivered (6000 cGy local brain irradiation, fractionated over 6 weeks). Follow-up MR imaging showed no recurrences of the tumour and no other lesions. Ten years later, at the age of 49, she consulted for progressive drug-resistant headache. MR imaging revealed two new well defined areas of different signal intensity at the surface of each frontal pole. Both lesions were surgically removed; the histopathological diagnosis was cavernous angioma. This is the first case of cavernous angioma after radiation therapy for atypical meningioma : it confirms the development of these lesions after standard radiation therapy also in patients previously affected by non-malignant tumours.

Endoscopic endonasal approaches for cerebrospinal fluid leaks repair.

OBJECTIVE: A variety of techniques have been described for the repair of cerebrospinal fluid (CSF) leaks at the anterior skull base. Conservative management includes bed rest, avoidance of straining activities, and temporary CSF diversion with serial lumbar punctures or lumbar drains. Surgical repair may be achieved transcranially through a bifrontal craniotomy, extracranially through an external ethmoidectomy or frontal sinusotomy, or transnasally with microscopic or endoscopic visualization. METHOD: Between January 2006 and May 2011, 30 patients with nontraumatic and traumatic CSF rhinorrhea were treated at the Departments of Neurosurgery and Maxillofacial Surgery of the Universities of Rome 'La Sapienza'. All patients underwent surgery: 5 patients (15%) were treated by a combined intracranial and endoscopic endonasal approach and 25 patients were treated (91.1%) by the endoscopic endonasal approach alone. In our study, we used autologous material, the fascia lata, free grafts of septal or middle turbinate mucoperichondrium, and septal cartilage grafts, and in cases with a large deficit in the posterior wall of the sphenoid or clivus, a pedicle flap from sphenopalatine artery of septal mucosa is used. RESULTS: Only in 2 cases was there an appearance of secondary rhinoliquorrhea with a success rate of 94%, in line with what is described in international literature. CONCLUSIONS: Posttraumatic cerebrospinal leak in our experience can be treated through endoscopic approach, in selected cases, using autologous materials with a few relapse of the pathology. Endoscopic endonasal technique offers a high viewing of surgical field and it permits to manage even larger lesions with minimally invasivity.

Postoperative extradural hematomas.

Postoperative extradural hematoma (POEH) is a possible complication after head surgery, often neglected in the literature. In a single surgeon experience we found 13 cases of POEH (0.8%). We distinguished two subtypes: (1) larger hematomas (>40 cc) with typical features and overt clinical picture that always needed evacuation, and (2) smaller hematomas (<40 cc) with insidious clinical onset and different radiological features compared with traumatic and spontaneous extradural hematomas. On the basis of our experience, we propose that clinical picture and radiologic appearance lead the decision between conservative or interventional treatment of type II hematomas.

Extent of tumor removal and molecular markers in cerebral glioblastoma: a combined prognostic factors study in a surgical series of 105 patients.

OBJECT: In this paper, the authors' goal was to evaluate the prognostic value of YKL-40 expression as a prognostic factor for glioblastomas and to compare its validity to the already known MGMT. METHODS: Between January 2002 and January 2007, 105 patients were treated for cerebral glioblastoma. The extent of removal was classified in 4 groups. YKL-40 expression was evaluated by a semiquantitative immunohistochemical staining scale (0, no staining; 1, mild expression; and 2, strong expression). MGMT promoter methylation status was analyzed with methylation-specific polymerase chain reaction. All patients received adjuvant radiotherapy and chemotherapy. Kaplan-Meier curves were used to analyze progression-free survival (PFS) and overall survival (OS), and to compare these parameters between the subgroups stratified by extent of surgical removal, MGMT methylation, and YKL-40 expression. The log-rank test was used to determine statistical significance. A multivariate regression analysis was applied to extent of removal, YKL-40 expression, and MGMT status to check their specific statistical power and to test the independence of the variables. RESULTS: There were 55 men and 50 women with a mean age of 58 years. Extent of surgical removal is reported. The MGMT promoter was methylated in 48 patients and nonmethylated in 57. Analysis of YKL-40 expression is reported. The median PFS was 10.7 months (14.9 months in the gross-total removal subgroup) (p < 0.0001), and the median OS was 12.5 months (17.4 months in the gross-total removal group) (p < 0.0001). In the univariate analysis, OS was significantly correlated to the extent of resection (p < 0.0001), MGMT status (p < 0.0001), and YKL-40 (p < 0.0001). Multivariate analysis showed that all 3 factors reached statistical significance with respect to patient survival. In particular, surgical removal contributed more than the 2 other factors to the survival prediction (ß = -0.6254). Interestingly, YKL-40 (ß = -0.3867) contributed more than MGMT (ß = -0.1705) to the predicted survival. CONCLUSIONS: The extent of removal is the most important factor influencing the OS of patients harboring glioblastomas. When biological aggressiveness is taken into account, YKL-40 expression was found to be an independent prognostic factor that predicts OS better than MGMT status.

Frameless stereotactic cerebral biopsy: our experience in 296 cases.

AIMS: To evaluate the reliability, safety and accuracy of a the frameless stereotactic system in our clinical series and the differences between head fixation by means of a standard Mayfield head holder and the pinless FESS frame, and to evaluate the usefulness of biopsy targeting on the basis of magnetic resonance spectroscopy (MRS) data. METHODS: The spectroscopic analysis was used to facilitate the targeting of the lesion. The fusion image function embedded in the Neuronavigation Unit was used postoperatively to assess the level of accuracy of the biopsy. The grading of the glioma specimens was correlated to the spectroscopic data. RESULTS: 296 patients underwent cerebral biopsy in 8 years. The diagnostic yield was 99.7%. The spectroscopic choline/N-acetyl aspartate ratio in different areas of the same tumor correlated well with the histological grading of the lesion. CONCLUSION: The frameless stereotactic systems guarantee excellent biopsy results. Advanced imaging, in particular MRS, facilitates the correct targeting of nonenhancing lesions.

Fourth ventricle meningiomas: a rare entity.

Fourth ventricle meningiomas (FVMs) are rare, often misdiagnosed, lesions. To the best of our knowledge, 47 cases have been reported in the literature: we describe our series of three cases treated at our Institution, focusing on some diagnostic tips and intraoperative features of these tumours. Our three patients have a history of headache. Gait disturbances, vomiting and/or diplopia complicated the clinical picture before the referral at our Department. The operations were uneventful, and the patients fully recovered from neurological symptoms. They are free of recurrence at a median follow-up of 19 years. FVMs are rare lesions, which are difficult to differentiate preoperatively from the much more common ependymomas. A preoperative distinction would be extremely advantageous: indeed, although both tumours share similar radiological and clinical patterns, they clearly differ as to surgical difficulty and outcome. In fact, meningiomas are comparatively easier to remove, granting better clinical results.

35 year-old man with falcine tumor.

A 35-year-old man presented with one month history of vomitus, dizziness and headache. CT and MR imaging revealed a 3.5 x 3.2 cm solitary extra-axial midline mass arising from the frontal falx cerebri; radiological findings were diagnostic of meningioma of the falx. At surgery, the tumour appeared as an extra-axial lesion and was removed via a left midline frontal craniotomy. Macroscopically, the surgical specimen was whitish, soft, well circumscribed and measured 1.6 cm in diameter; microscopic features showed a neoplasm with high cellularity, presence of mitotic figures, without necrosis or microvascular proliferation; the neoplasm was reactive for glial fibrillary acidic protein and MIB-1 index was about 15%. Given the localization, microscopic features were diagnostic of primary intracranial solitary leptomeningeal astrocytoma (PLA), WHO grade 3. PLA is a very rare lesion that arises in the leptomeninges of the brain or spinal cord with no involvement of intraparenchymatous tissue. Fifteen cases of PLA are reported in the literature. Retrospective neuroradiological analysis of this case failed to detect any findings to help in the differential diagnosis, thus confirming the fundamental role of the neuropathologist even in what can firstly appear to be a straightforward radiological diagnosis.

Endoscopic assistance in the epidural subtemporal approach and Kawase approach: anatomic study.

BACKGROUND: Few reports exist in the literature about the use of endoscope assistance in the identification of structures in the posterior fossa. OBJECTIVE: To asses the advantage of endoscopic assistance in the epidural subtemporal and Kawase approaches by studying anatomic exposure and surgical freedom in the posterior cranial fossa. METHODS: Twelve epidural subtemporal approaches were performed on 6 adult cadaveric heads. On the same specimens, 6 endoscope-assisted subtemporal approaches and 6 Kawase approaches were then performed. At the end of each Kawase approach, endoscope assistance was used. The microsurgical observations were performed with a surgical microscope with magnification ranging from 4 x to 40 x. Endoscopic observations were made with a 0 degrees , 4-mm rod-lens endoscope. Anatomic exposure and surgical freedom were analyzed. RESULTS: Endoscopic assistance during the epidural subtemporal approach increased the anatomic exposure 3 mm superiorly, 20 mm inferiorly, and 10 mm medially from the trigeminal nerve. Surgical freedom was limited in the temporal lobe, the petrous apex, and the trigeminal nerve. The amount of increased anatomic exposure obtained with endoscopic assistance during the Kawase approach was 26 mm inferiorly and medially from the trigeminal nerve. Surgical freedom was limited by the brainstem and the depth of the posterior cranial fossa. CONCLUSION: The endoscope-assisted subtemporal approach can be useful in visualizing tumor in the posterior fossa. It can help the surgeon in planning further surgical steps through consideration of the size, extension, and adherence of the tumor to surrounding structures. The endoscope-assisted Kawase approach permits maximum anatomic exposure of the posterior cranial fossa, although the deepest neurovascular structures could be better addressed with more direct approaches.

Cavernous sinus meningiomas: retrospective analysis and proposal of a treatment algorithm.

OBJECTIVE: Today, meningiomas with primary or, more commonly, secondary involvement of the cavernous sinus remain a surgical challenge. Anatomic research on cadaver specimens, together with the advances made in cranial base and microvascular surgery over the past 2 decades, have made it possible to completely resect lesions within the cavernous sinus. However, the technical complexity of some procedures, coupled with the current availability of less-invasive therapeutic options, makes the rate of complications related to surgical extirpation of intracavernous meningiomas unacceptably high, especially regarding permanent neurological morbidity and mortality. Currently, indications, timing, and multimodal treatments with surgery and radiotherapy represent the main topics of discussion concerning these lesions. METHODS: One hundred forty-seven patients underwent surgery between 1985 and 2003. The patients were retrospectively divided into 2 groups according to the type of surgical treatment: group A (open sinus surgery) and group B (closed sinus surgery). The mean follow-up time was 9.7 years. RESULTS: Early postoperative morbidity and permanent postoperative morbidity showed significant differences between the groups. At long-term follow-up, we found no statistical differences in the incidence of recurrences and progressions. Only patients treated with postoperative radiation therapy (81.5%) showed clinicoradiological stability. CONCLUSION: Growth control and preservation of neurological functions are the primary goals in the treatment of cavernous sinus meningiomas. In most cases, surgery and radiosurgery alone do not reach the primary goals, and unresolved issues remain. Therefore, we have developed a treatment algorithm as a guide to the best therapeutic options for the most common presentations of the disease.

Aesthetic issues in neurosurgery: a protocol to improve cosmetic outcome in cranial surgery.

Nowadays, surgical interventions must treat with care the aesthetic impact on the patient, even when a malignant pathology or an patient's advanced age could give the aesthetic issue lower priority. The cranio-facial area is probably the most important anatomical region with regard to the harmony of the human body. Consequently, a step-by-step procedure, applicable regardless of the site and the nature of the lesion, is advisable to minimize the aesthetic impact. We prospectively analyzed 65 patients during a period of 2 years. At 1-year follow-up, all patients were invited to undergo a 3D-multislice CT and to complete a questionnaire with a subjective rating scale about aesthetic impact. The 3D-multislice CT scan didn't show dislocations, depressions or gaps of the bone flap. Nevertheless, five patients complained of some degree of aesthetic injury, or reported a psychological suffering from the aesthetic consequences of surgery. As a control group, we retrospectively reviewed 223 patients. The authors describe their surgical protocol and discuss it in the light of the results of their series.

Klippel-Trenaunay-Weber syndrome and intramedullary cervical cavernoma: a very rare association. Case report.

BACKGROUND: Klippel-Trenaunay-Weber syndrome is a rare mesodermal phakomatosis characterized by cutaneous hemangiomata, venous varicosities, and osseous-soft tissue hypertrophy of the affected limb. As the pathologic aspect of KTWS arises from the site in which malformations occur, the clinical picture varies widely from patients who complain for cosmetic reasons to patients with life-threatening lesions. CASE DESCRIPTION: We describe a very rare case in which KTWS was associated with a cervical intramedullary cavernous angioma surgically treated. CONCLUSION: This report confirms the wide range of expression of vascular abnormalities in neurocutaneous developmental diseases and the need of a careful multisystemic evaluation of these patients.

Intraventricular neurocytoma with massive brain stem involvement in a 5-year-old child.

INTRODUCTION: Central neurocytoma is a tumor of neuronal origin that should be taken into consideration in the differential diagnosis of intraventricular neoplasms. Reports of neurocytomas with an extraventricular localization are rare: to our knowledge, the case described here is the first in which a neurocytoma developed within the ventricles but also invaded the brain stem. CASE REPORT: The authors describe the unusual case of a 5-year-old boy with an intraventricular neurocytoma presenting with massive involvement of the basal nuclei and the brain stem. The patient underwent first biopsy and then surgery for ventricular-peritoneal shunting and partial removal of the tumor. Histology showed the tumor to be a typical neurocytoma with Mib-1 <2%. The postoperative course was uneventful. At 3 years' follow-up, the patient's clinical condition is stable and there are no signs of disease progression. DISCUSSION: The literature is reviewed and the characteristics of this unusual tumor are discussed.

Anterolateral approach to the craniocervical junction.

OBJECT: The authors present the surgical results obtained using the anterolateral approach to the craniocervical junction (CCJ) to resect a lesion with an extradural component located anterolateral to the foramen magnum and upper cervical spine. METHODS: The anterolateral approach, which is a presternomastoid retrojugular route to the CCJ, was performed in 14 patients. The skin incision follows the anterior edge of the sternomastoid muscle. The vertebral artery (VA) was exposed at C-1. This approach was extended either down to the cervical spine or anteriorly to the jugular foramen, according to specific requirements. Two patients had previously undergone other surgical procedures. The follow-up period ranged from 4 months to 6.2 years. The tumor resection was complete in 11 cases and subtotal in two. In a case of vertebral coiling, a vein graft was interposed between the V1 and the V3 segments of the VA, and the bypass was still patent at the 2-year follow-up examination. In two cases involving a glomus tumor, there was a transitory postoperative seventh cranial nerve deficit. CONCLUSIONS: The aforementioned technique allows for sufficient access to lesions located anterolateral to the CCJ. It is indicated in cases in which lesions exhibit a significant extradural component, and it provides good control of the VA, the cervical portion of the internal carotid artery, sigmoid-jugular complex, and lower cranial nerves. This approach can easily be combined with a posterolateral approach and can be extended anteriorly toward the jugular foramen and inferiorly toward the lower cervical spine.