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Purpose Human falx cerebelli is an important anatomical structure in regard to its relations with venous structures during infratentorial approach to reach cerebellar tumors, vascular malformations, traumatic hemorrhage and Chiari malformations. The present study aim to describe the different types of variations of the falx cerebelli, its morphological features and its association with occipital venous sinuses. Method In this study 49 dura mater was obtained from the Institution of Forensic Medicine. The length, width and the depth of the falx cerebelli were measured using a digital compass. The data obtained were statistically analyzed in relation to age and gender. The relations of the falx cerebelli with the occipital sinus was documented. Histological sections from the falx cerebelli were stained with Hematoxylin Eosin to evaluate the fine structure. Results Among the 49 falx cerebelli examined 36 (73.5%) were classified as normal. The average length, width and depth of the normal falx cerebelli was 3.7, 1.0 and 0.4 cm respectively. Of the 49 falx cerebelli in 1 (2%) case it was absent, in 5 cases (10.2%) duplicate, in 5 cases (10.2%) triplicate, in 1 (2%) case quadruplets and in 1 case (2%) it was five-folded. The proximal and the distal attachments of the falx cerebelli showed 3 types of variations; both attachments triangular, the proximal attachments triangular and the distal ramified and distal attachments triangular and the proximal attachments ramified. The drainage of the occipital sinus of falx cerebelli with variations were evaluated. The increased number of falx cerebelli highly corresponded with the increased number of occipital sinus. Conclusions The dural-venous variation in the posterior cranial fossa can be problematic in various diagnostic and operative procedures of this region. Neurosurgeons should be aware of such variations, as these could be potential sources of haemorrhage during the midline suboccipital and infratentorial approaches.

WOS: 000452839400017 PubMed ID: 30067116 Purpose: Cerebrospinal fluid (CSF) fistula is one of the most common complications encountered after cranial surgeries. In cases where CSF fistula frequently appears due to surgical technique, dural sealants are used as auxiliary preparations to prevent CSF fistula and provide convenience to the surgeon. Materials and Methods: Data obtained from 128 number of cases where cyanoacrylate (CA) had been used for dural repair to prevent CSF fistula was evaluated, retrospectively. The cases of skull base and frontal sinus fractures where the primary repair had not been carried out were also included in the study. Results: The mean follow-up of all cases was 9,7 months. CSF fistula was not encountered in 121 of 128 cases. 4 of the cases developed CSF fistula in the early period. 3 of the cases presented with CSF fistula in the late period after discharge. No side effects due to hypersensitivity or preparation were encountered. Conclusion: CA can help dural repair against the development of CSF fistula by taking effect quickly. Also, it is a rapid anti-haemorrhagic agent. It can also be used after posterior fossa surgery, skull base surgery where dural repair is difficult, or during sinus repair.

Chordomas are rare bone tumours that are aggressive and locally invasive. When arising from the clivus, they typically present with cranial nerve deficits and headache. We report a case of a 58-year-old male who presented acutely with hydrocephalus and suspected encephalitis. He had evidence of clival erosion but no obvious tumour mass on imaging. After stabilisation, he developed CSF rhinorrhoea for which he underwent endoscopic repair. Biopsy samples diagnosed chordoma.

PubMed ID: 29207882 Purpose: Lateral supraorbital approach is a simpler and quicker method than pterional approach. It provides a more anterior projection when compared to the pterional approach. There are some minor differences of the modified lateral supraorbital approach when compared to lateral supraorbital approach. It is directed more subfrontally and anterior than the pterional and lateral supraorbital approach. Material and methods: We used modified lateral supraorbital approach in 100 cases between 2012 and 2015 in Medical Park İzmir Hospital/Turkey. The assessed data were as follows: age, gender, Glasgow coma scale at admission, the localization of pathology, the condition of surgical obliteration for aneurysm, excision grade for meningioma, length of stay in the hospital and Glasgow outcoma scale at discharge. Results: Of all patients, 58 (58%) were men and 42 (42%) were women. Our cases were anterior communicating artery aneurysms (41 cases), tuberculum sella and medial sphenoid wing meningiomas (22 cases), middle cerebral artery aneurysms (15 cases), olfactory groove meningiomas (15 cases), anterior choroidal artery aneurysms (4 cases) and posterior communicating artery aneurysms (3 cases). 4 patients died and the mortality rate of the study cohort was 4%. Conclusions: The MLSA is faster, simpler and less invasive than the PA and LSA. © 2017, © 2017 The Neurosurgical Foundation.

Purpose: In many brain surgeries, dura cannot be primarily repaired and it is necessary to use a graft. Appropriate repair of dura plays a major role in preventing CSF leakage and meningitis. In th...

Background: Posterior fossa decompression both with and without duraplasty are accepted treatments for symptomatic adult patients with Chiari Malformations Type 1 (CM-1). There is still deb...

Purpose: Clival Chordomas are locally aggressive tumours which pose a significant treatment challenge. Endoscopic endonasal approach for clival chordomas is correlated with higher resection rates and lower morbidity rates in comparison to open approaches. We present our initial single institution experience and short-term patient outcomes following endoscopic endonasal approach for resection of clival chordomas. Materials and methods: This is a retrospective analysis of ten patients undergoing endoscopic endonasal approach for clival chordomas in our neurosurgical unit over a 6 year period between August 2010 and September 2016. The procedures were performed using two surgeons, four hands, binostril endoscopic endonasal approach with a Karl Storz® endoscope and intraoperative BrainLab® image guidance. Results: Overall 15 endoscopic endonasal approach resections of clival chordoma were performed in 10 patients with median follow up period of 39.5 months (range 9-76). Gross total resection was achieved in 4 cases (40%), near total resection in 4 cases (40%) and subtotal resection in 2 cases (20%). 5 cases (50%) required revision resections. Cerebrospinal fluid leak occurred in 2 patients. 1 case of meningitis occurred in a patient with revision surgery. There were no new neurological deficits post operatively with 3 patients demonstrating resolution of diplopia post operatively. No recurrence occurred following gross total resection. 1 out of 4 cases of near total resection showed evidence of progression during the follow up period. Both cases of subtotal resection demonstrated evidence of progression with one dying of unrelated cause during the follow up period. Conclusion: Endoscopic endonasal approach represents a safe technique for debulking and resection of clival chordomas. Due to the rarity of clival chordomas, it is important that patients with this pathology are managed in high volume skull base centres where a multi-disciplinary team approach is available.

To acknowledge the challenges and limitations of image-guided neurosurgery systems, we compared the application accuracy of two different image registration methods for one commercial system. (VectorVision, BrainLab, Germany).We used an anthropomorphic head phantom for radiosurgery and a custom built add-on to simulate surgical targets inside the brain during an image-guided neurosurgery. We used two image registration methods, fiducial registration using attachable surface markers for computed tomography (CT) and surface registration using infrared laser face scanning. After simulation, we calculated the three-dimensional (3D) distance between the predicted position of a target, and its actual position using a registered pointer and an infrared camera. Deviations were measured for both superficial fiducial markers and internal surgical targets by five different users.Deviations from the location of fiducial markers after each registration method were 2.15 ± 0.93 mm after CT surface marker registration and 1.25 ± 0.64 mm after infrared face scanner registration. The mean target registration errors were 2.95 ± 1.4 mm using fiducial registration and 2.90 ± 1.3 mm using surface registration. The largest deviations (6.2 mm) were found for the targets in the skull base and posterior cranial fossa. Fiducial deviations and target registration errors were statistically uncorrelated. The total application accuracy was 4.87 ± 0.97 mm after CT surface marker registration and 4.14 ± 0.64 mm after infrared face scanner registration.Despite others have reported differences, we did not find significant variations between both registration methods for the target registration error, although application accuracy was slightly better after surface face registration. Superficial registration errors, but not the target registration error, can be routinely evaluated in the operating room. Since both errors were uncorrelated, surgeons may neglect the achievable accuracy of the procedure. The described method is recommended to assess application accuracy in the operating room.

Background. State-of-the-art treatment for Chiari Malformation I (CM-I) consists of decompression by posterior fossa craniectomy. A rare but severe complication that develops over months to years after this procedure is cerebellar slump. Treatment options for this condition are limited. We present a new and promising approach to treat this rare condition. Methods. The patients were placed in the Trendelenburg position to facilitate ascent of the cerebellum. After almost complete dissolution of neurologic symptoms, surgical reconstruction was performed by tonsillar resection and the creation of a new structural support using a bone graft. Results. Both patients experienced good clinical and morphological outcomes immediately after surgery, and for two years thereafter. Conclusions. Neurological symptoms related to cerebellar or brainstem slump can be adequately reversed by placing the patient in the Trendelenburg position. After uneventful gravitational reversal of the slump, safe surgical reconstruction of the cerebellar support can be performed to securely preserve the anatomical reversal.

The management of obstructive hydrocephalus associated to posterior cranial fossa tumor remains a controversial issue. In this context, the role of endoscopic third ventriculostomy (ETV) performed before tumor removal (the so-called preoperative ETV) is debated and its success rate is reported as being largely variable in the literature. We describe two children who experienced the closure of a preoperatively performed ETV after the surgical resection of their posterior fossa tumor. In both cases tumor removal was performed in the prone position. Radiological investigations and intraoperative evidence documented that the failure of the ETV was due to a blood clot which directly occluded the stoma. We speculate that the prone position favored the migration of blood, through the aqueduct, thereafter, clotting on the most declivous part of the third ventricle once the patient assumed the upright position, with the consequent occlusion of the stoma. Based on a gravitational hypothesis, we named this mechanism the "snow globe effect."

Canalis Basalis Medianus is a rare congenital normal anatomically variant of the clivus .We report a very rare case of cerebrospinal fluid leak from a canalis basilaris medianus in a 22-year-old male, who presented to our hospital with frontal headache and running nose two weeks after an elective septoplasty.

measuring intracranial pressure (ICP) is considered the gold standard of care for brain injury. While supratentorial ICP monitoring has been adopted everywhere, posterior fossa ICP monitoring is rarely performed. In this study, we aimed to evaluate the feasibility of inserting ICP sensors into the posterior fossa of cadavers, to measure ICP in the posterior fossa.An ICP sensor was transcranially implanted into the posterior fossa of fifteen fresh adult cadavers. An extracranial point was defined in the retroauricular area 2 cm behind the tip of the mastoid process and 2 cm below the transverse sinus, in order to implant an ICP probe. The cranial cavity was opened and measures were taken of the distance that the ICP sensor had penetrated inside the posterior fossa, as well as the distance to nearby venous sinuses (lateral, transverse, sigmoid, inferior petrosal sinus, and jugular bulb). The cerebellar hemisphere was searched for any possible damage.the selected extracranial point (2 cm behind the tip of the mastoid process and 2 cm below the transverse sinus) was a safe location. Intracranial structures such as the brainstem and the cerebellar hemisphere were not damaged. The implanted ICP probe was at least 2 cm away from the venous sinuses, which were not damaged.ICP monitoring is safe and reliable at the described ICP probe placement site of the posterior fossa.

Dermoid cysts of posterior fossa are uncommon benign lesions. They differ from other lesions found in the infra tentorial compartment by virtue of their associated conditions. Due to their association with dermal sinus tracts, intracranial infection is a potential threat following infection of the cyst. Due to their embryologic origin, these cysts may also be associated with other congenital anomalies. In this article we detail our eleven-year-experience with posterior fossa dermoid cysts in fifteen patients. Despite the morbid presentation with severe life-threatening complications, the overall outcome was excellent. Implications of the various associations are discussed.

Malignant transformation of intracranial epidermoid cysts to squamous cell carcinoma is a rare occurrence and only a small number have been reported to date. MRI recurrence in combination with neurological decline should prompt surgery to exclude malignant transformation. Herein, we describe our experience of such a case and contribute to the evolving series within the literature.

Tumours in the petroclival region have been a challenge to neurosurgeons. We present a cohort of 24 patients with petroclival meningioma (PCM) and trigeminal schwannoma (TS) in the petroclival region with extension to the middle fossa which were removed with the temporal base intradural transpetrosal (TBIT) approach.To avoid damage to the important surrounding structures in the petrosal bone, a morphometric analysis in the TBIT approach was performed in 15 cadaveric heads, and the 'safe area of intradural petrosectomy' was identified in the TBIT approach. Subsequently, 14 patients with PCM and 10 patients with TS in the petroclival region were operated on with the TBIT approach.There were no operative deaths in this cohort related to the surgery. Common complications included light hemiparesis in two patients (8.0%), new cranial nerve paresis in nine (37.5%), post-operative pneumonia in one (4.0%) and transient cerebrospinal fluid leak in one (4.0%). Total tumour resection was achieved in 20 patients (83.3%) and subtotal resection in 4 (16.7%). There was no tumour recurrence in all patients at follow-up with a mean duration of 37 months.Surgical strategy for PCM and TS in the petroclival region should be tailored to individual patients. The TBIT approach may improve the exposure of tumours in the petroclival region. A clear description of the 'safe area of intradural petrosectomy' appears to decrease the risk associated with petrosectomy procedure in the TBIT approach.

Chiari malformations are a pathological continuum of hindbrain maldevelopment and Chiari I malformation (CMI) represents caudal decent of cerebellar tonsils. The surgery aims to relieve tonsillar compression with restoration of the normal cerebrospinal (CSF) flow dynamics. We report the salient features of our surgical experience with CMI; over a decade of management of 87 patients. Most (57) presented with pain and weakness was predominant motor complaint (n = 34). The associated bony anomalies were seen in 25 patients. For clinical grading and outcome analysis, modified Klekamp and Samii scoring system was used. The majority of patients were in poor grades (n = 43); 79 patients improved following surgical intervention at a mean follow-up of 34.21 + 21.53 months. The bony decompression and establishment of CSF flow dynamics are needed, and posterior fossa decompression in symptomatic patients offers success in the majority of patients with minimal complications.

We report the case of a young patient with a transient transitory spinal accessory injury after foramen magnum decompression for Chiari malformation. The pathophysiology and the possible mechanisms of injury are highlighted and discussed. Some tips to avoid this potentially severe iatrogenic complication are provided.

We read with interest the case report of de Jong et al.1 describing two cases of spontaneous intracerebellar migration of a pseudomeningocele. In this report, the authors indicate that the probable...

Next to multiple myeloma, osteosarcoma is the commonest primary malignant neoplasm of skeletal system. These are aggressive tumours, composed of spindle cells producing osteoid and rarely occur in calvaria. The authors report a 55-year-male harbouring clival osteosarcoma, his clinical presentation, radiological findings, management and outcome.

Intraparenchymal posterior fossa neoplasms containing intratumoural abscesses are rare. Intrasellar or parasellar tumours are among the common neoplasms developing such a complication, as the result of direct extension of the microbial flora from the contiguous infected sinuses. All meningiomas reported with such a complication have been located parasagittally. A short series of three posterior fossa tumours, containing intra-tumoural abscesses, are described, of which only one was diagnosed pre-operatively. A haematogenous pathway was considered as the mode of spread in all three patients. Magnetic resonance imaging was performed in all patients and the features are discussed.

Retroclival haematoma are rare, and usually related to high-energy trauma.1 We present the case of a 46-year-old woman with a 5-day history of headache, vomiting, palpebral ptosis, ophthalmoplegia,...

We present two cases of spontaneous intracerebellar migration of a pseudomeningocele. This is a rarely reported complication of posterior fossa surgery with possible life threatening cerebellar mass effect. The probable mechanism is a slow but progressive cerebrospinal fluid (CSF) movement (one-way valve mechanism) into the pseudomeningocele with secondary herniation or dissection through a weakened dura into the cerebellum causing progressive or acute cerebellar dysfunction. Evacuation and dural repair with or without CSF shunting or marsupialisation results in resolution of the symptoms.

We present an asymptomatic case of Lhermitte–Duclos disease (LDD) in a 40-year-old woman and discuss the diagnosis, management and prognosis of this rare disease. Surgical intervention is strongly recommended as an initial therapy strategy even in asymptomatic adult patients. Conservative strategies could be chosen if the mass involves the brainstem or is accidentally found in the elderly.

Subtemporal craniotomy centred on the external ear canal and its basal extension, involving resection of the roots of the zygomatic arch, roof of the external ear canal and superior third to half of the mastoid bone was used to treat surgically 24 meningiomas located in the petroclival region, having their maximum bulk at the level of tentorium. The approach was found to be suitable for dealing with middle fossa extensions of the tumour in addition to the part extending up to the mid-clivus or vertebrobasilar junctional region. The direction of the approach to the petroclival region was the shortest and most perpendicular from surface and avoided any neural or vascular exposure or manipulation. The basal exposure was horizontally wide and significantly low, which reduced the operating distance, limited the extent of temporal lobe retraction and provided additional space for manipulation of instruments. The exposure was manoeuverable with anterior, posterior and medial expansion being possible during or prior to tumour resection. The approach had the advantage of being simple and relatively quick, and of its familiarity to general neurosurgeons. The experience with the approach with petroclival meningiomas and its possible advantages over other available approaches to these lesions are analysed in this report.

A retrospective analysis of seizure incidence in 511 patients who underwent posterior possa operations via a suboccipital craniectomy with prophylactic anticonvulsant agents, was performed. Thirty patients (5.9%) experienced seizures within 2 weeks postoperatively. Their mean age was 15 years. Twenty patients had seizures within 3 h of operation; 24 patients had generalized tonic clonic seizures. Focal motor seizures with secondary generalization and simple focal motor seizures were recorded in three patients each. The incidence of postoperative seizures was highest in patients with acoustic schwanommas (9.09%) followed by those with medulloblastomas (8.54%) and astrocytomas (8.33%). The sitting position, associated with venous air embolism (VAE) and or pneumocephalus, was related to the occurrence (p = 0.001) of postoperative seizures. Seizures occurred in 24 patients out of 250 cases operated on in the sitting position compared with 3/170 and 3/91 in the prone and lateral positions, respectively. Intraoperatively significant VAE occurred in 10 out of 30 patients and postoperative computed tomography revealed pneunocephalus in 20 out of 30 patients. A higher percentage was found in patients with a preoperative ventriculoperitoneal shunt or intraoperative ventriculostomy (6.5%) than in those without (5.1%), but the difference was not statistically significant. In conclusion, seizures after posterior fossa surgery are a significant problem which is not reflected in the published literature. Our study highlights the significance of the sitting position in the causation of seizures after posterior fossa surgery.

Two patients with posterior fossa arachnoid cysts associated with syringomyelia are discussed adding to the five cases already reported in the literature. The formation and progression of syringomyelia secondary to a posterior fossa cyst and its possible pathophysiology by dynamic CSF flow studies using magnetic resonance (MR) imaging are discussed and reviewed.

We present a rare case of acute cavernous sinus syndrome due to a renal cell carcinoma metastasis to the clivus. This case highlights the role of palliative endoscopic endonasal decompression of the cavernous sinus to relieve cranial neuropathies, obtain tissue diagnosis, and for cytoreduction in preparation for additional adjuvant therapy.

There are only three cases of arachnoid cysts inducing twelfth nerve paresis described in English medical literature. We herein report one more instance. Six weeks after surgery, the patient has almost fully recovered. This case underlines the importance of considering the arachnoid cyst as a possible cause of twelfth nerve paresis.

BACKGROUND. The endoscopic endonasal transclival approach (EETCA) is a minimally-invasive technique allowing a direct route to the base of implant of clival lesions with reduced brain and neurovascular manipulation. On the other hand, it is associated with potentially severe complications related to the difficulties in reconstructing large skull base defects with a high risk of postoperative cerebrospinal fluid (CSF) leakage. The aim of this paper is to describe a precise layer by layer reconstruction in the EETCA including the suture of the mucosa as an additional reinforcing layer between cranial and nasal cavity in order to speed up the healing process and reduce the incidence of CSF leak. METHODS. This closure technique was applied to the last six cases of EETCA used for clival meningiomas (2), clival chordomas (2), clival metastasis (1), and craniopharyngioma with clival extension (1). RESULTS. After a mean follow-up of 6 months we had no one case of postoperative CSF leakage or infections. Seriated outpatient endoscopic endonasal controls showed a fast healing process of nasopharyngeal mucosa with less patient discomfort. CONCLUSIONS. Our preliminary experience confirms the importance of a precise reconstruction of all anatomical layers violated during the surgical approach, including the nasopharygeal mucosa.

We describe a case of adult onset Dandy-Walker syndrome. A 35-year-old woman presented with symptoms of increased intracranial pressure and cerebellar signs. After excision of the cyst wall of the posterior fossa. The patient recovered completely. The role of magnetic resonance imaging in establishing the diagnosis and following the course of operation are emphasized. Possible pathophysiological mechanisms involved in the late appearance of the clinical symptoms and the treatment of this anomaly are discussed.

Prolactinomas are common secretory pituitary tumours, usually managed with dopamine agonists. There have previously been case reports of rarer giant prolactinomas causing invasion of surrounding structures. We describe a case report of an exceptionally aggressive giant prolactinoma that eroded the occipital condyles causing cranio-cervical joint instability mandating surgical fixation.

Seventy-three patients with posterior fossa meningioma were operated upon between July 1975 and September 1992. The authors attempt a simple classification of these tumours. Fifty-five were women (average age: 48 years) and 18 were men (average age: 52 years). Frequently, there was gait disturbance except in tentorial meningioma where headache was the most common symptom. The most common physical finding was a cranial nerve deficit (77%). All patients underwent CT and angiography. More recently, MRI was used and found very helpful. Surgical approaches used were either a suboccipital craniectomy, a subtemporal craniotomy or a combined suboccipital-subtemporal approach. Tumour resection was complete in 57 (78%) cases. There were no operative deaths. Thirty-three per cent of patients were left with permanent deficits: mainly cranial nerve deficit (47%). Seventy-seven per cent of patients out of the 57 who could be followed up are functioning independently, 21% of these having no neurological deficit. With proper neuroradiological evaluation, good selection of patients and microneurosurgical techniques posterior fossa meningiomas can be completely excised with an acceptable complication rate.

Some degree of hydrocephalus is present in almost all cases of medium to large posterior fossa tumours. The initial symptoms in such cases are usually due to the hydrocephalus and the consequent increased supratentorial pressure, and more often precede the symptoms primarily due to the local invasion and compression of the brain stem and cerebellum by a significant length of time. In our experience, based on 62 posterior fossa tumour operations, insertion of a cerebrospinal fluid (CSF) diverting shunt because of hydrocephalus makes the subsequent tumour excision more difficult and hazardous. The various problems presumed to be related to preoperative shunt surgery are discussed in this report. It is concluded that preoperative shunts for posterior fossa tumours are rarely indicated.

Intra-extracranial schwannomas arising unrelated to major cranial nerves are exceedingly rare neoplasms. We report the case of a 23-year-old male who presented with a 9 month history of progressive temporal swelling which was excised and found histologically to be a schwannoma. A succinct review of the relevant literature is presented.

A posterior fossa epidural haematoma (EDH) is uncommon and the diagnosis is difficult because the clinical symptoms are non-specific. Therefore, a computed tomography scan is important for the early diagnosis and management. Thirty-four patients with a posterior fossa EDH were admitted between 2001 and 2008. A retrospective analysis of the clinical and radiographic findings with regard to outcome and prognostic factors was carried out. The Glasgow Coma Scale (GCS) score on admission was recorded to be: one in 3-5, five in 6-8, six in 9-12 and 22 patients in 13-15. The admission GCS score was the most valuable prognostic factor. Among the 28 patients with a GCS score of more than 9, 27 patients survived with good results; for the six patients with a GCS score of less than eight, two patients had good recovery and four patients had unfavourable outcome. The 15 patients that were conservatively treated and 14 out of the 19 patients surgically treated had a good recovery. Among the other surgically treated patients, two were moderately disabled, two remained in a vegetative state and one died (overall mortality 2.9%). An occipital fracture was present in 28 cases. Six patients with a diastatic fracture of the lambdoid suture had a more complicated venous sinus injury requiring early surgery compared to those with a simple linear fracture. The patients admitted with associated intracranial injuries, such as a contrecoup injury including subdural haemorrhage or traumatic subarachnoid haemorrhage had a poor outcome. The initial GCS score on admission and the presence of associated intracranial injuries were important factors associated with the patient prognosis. A diastatic fracture of the lambdoid suture was associated with complicated venous sinus injuries making surgery more difficult.

A 14 year old boy presents with a gunshot wound into the roof of his mouth to lodge into the clivus, and miraciously he is neurologically intact. Keywords: gunshot wound, clivus, traumatic brain injury. Language: en

CSF leakage is a common complication of neurosurgical procedures, with defective dural suture thought to be the most frequent cause. We report our experience with a new collagen foil (TissuDura, Baxter Healthcare SA, Switzerland) utilized as dural substitute in paediatric neurosurgical procedures.TissuDura was used in children consecutively operated on at the department of paediatric neurosurgery, Catholic University, Rome, from March 2004 to August 2007. Children underwent surgical procedures in supratentorial, infratentorial and spinal compartments. In supratentorial and spinal procedures, the dural graft was used according to the overlay technique. In the posterior fossa procedures, the underlay technique was used.Forty-seven patients received TissuDura during surgery. Thirty-one patients underwent surgery for the removal of posterior fossa tumours, nine for supratentorial tumours and seven for spinal dysraphisms. No CSF leakage was observed following the use of TissuDura in supratentorial procedures. Two post-operative CSF leaks occurred in patients who had undergone spinal surgery. No post-operative hydrocephalus was noted in these two surgery groups. Three cases of CSF leakage occurred in patients who had undergone posterior cranial fossa surgery. All 3 cases had an associated supratentorial ventricular dilation present prior to the removal of the tumour (one case) or occurring after the tumour excision (two cases). No clinically evident adverse reactions directly related to TissuDura were observed.The main advantages of TissuDura were its apparent ability to prevent CSF leakage when utilized in a specific subset of patients, and the absence of reactions or postoperative infections.

Intracranial endodermal cysts are most commonly located in the posterior cranial fossa anterior to the brainstem. We report a rare case of an endodermal cyst of the posterior fossa located dorsal to the brainstem and is to our knowledge the only other such case reported in the literature.

Arachnoid cysts of the posterior fossa are rather uncommon compared with their supratentorial counterparts. Spontaneous disappearance of middle cranial fossa arachnoid cysts has been reported but there are none in the English literature on the spontaneous fluctuation in size of a posterior fossa arachnoid cyst. We present a 41-year-old male, with a midline posterior fossa arachnoid cyst, which appeared to lessen in size spontaneously with complete disappearance of symptoms and then enlarged with a worsening in neurological status.

Primary giant cell tumours of the craniospinal axes are rare lesions. These are benign, localized and lytic bony lesions with occasional malignant behaviour. Their clinical behaviour is unpredictable and, hence, management remains controversial. Radical excision of bony lesion, with adjuvant therapy helps in achieving the desired outcome. In the present communication, we present malignant giant cell tumour of clivus, managed successfully with surgical decompression and adjuvant therapy. Patient remains symptom-free at 2 years of follow-up.

This article presents the advances of three-dimensional (3D) virtual neuroendoscopy of the cranial nerves (CN) in the posterior fossa. Interactive 3D visualizations were generated and the anatomical landmarks, such as the root entry/exit zones (REZ) and cisternal segments of the CN were evaluated. Twenty patients (M:F, 6:14) with trigeminal neuralgia (TN) underwent MRI constructive interference in steady state (MRI(CISS)) imaging and subsequent 3D visualization based on explicit segmentation of the MRI(CISS) data and interactive evaluation with direct volume rendering including implicit segmentation. The 3D topography of the interesting CN V-X were evaluated with interactive and virtual neuroendoscopy. The anatomical landmarks of the CN V-X could be visualized in all 20 cases (100%). The systematic application of virtual neuroendoscopy could be realized in all patients for the non-invasive observation of the CN without any technical difficulties. Interactive 3D visualization using explicit and implicit techniques for segmentation, and 3D direct volume rendering is demonstrated to successfully identify 3D neurovascular relations in patients with trigeminal neuralgia. It has the ability to provide a useful tool for surgeons in the pre- and intraoperative evaluation of such cases.

We describe the case of a l-year-old boy presenting clinically and radiologically with a haematoma occurring in the cerebellum. Histological examination revealed a germ cell turnour with a pure germinomatous component. The patient subsequently succumbed with extensive tumour metastases in the spinal cord and the subcutaneous tissues of the scalp. This represents the first comprehensive documented report of a germinoma arising in the posterior fossa.

We describe a unique case of prolonged nausea and vomiting following posterior fossa craniotomy for removal of a meningioma. No apparent neurological or gastrointestinal causes were discovered except for a delayed gastric emptying time. The symptoms gradually resolved along with normalization of the gastric emptying time. Possible pathogenic mechanisms are discussed.

A retrospective analysis of 96 surgically treated tentorium and anterior tentorial hiatus-based epidermoid tumours from 1997 - 2004 is presented. The most prominent symptoms were headache (53.1%) and ataxia (44.8%). The average tumour size was 4.4 cm. Surgical approaches included posterior cranial fossa route (85 cases), basal subtemporal middle fossa route (9 cases) and combined posterior fossa and subtemporal routes in two cases. Total tumour resection was performed in 46 patients. Eight and four patients developed transient and sustained postoperative neurological deficits respectively. There was mortality in two patients. There was non-symptomatic recurrence of the tumour in two cases. Ninety-four patients are leading active functional lives. Radical and safe resection of anterior tentorium-based epidermoid tumours is associated with symptomatic relief and lasting cure. Extensive drilling of the petrous bone can be avoided. Gentle dissection of the tumour and capsule from the critical neurovascular structures can limit post-operative morbidity.

The authors report the case of a 45-year-old man who presented with a short duration of a painful ophthalmoparesis. Initial magnetic resonance imaging revealed an extraaxial petroclival mass characteristic of an epidermoid cyst, with the exception of a contiguous contrast-enhancing lobule. A subtotal resection was performed with the histopathological diagnosis revealing malignant transformation of an epidermoid cyst. Despite aggressive postoperative adjuvant therapy, the patient developed leptomeningeal metastasis and died shortly thereafter. The presence of contrast enhancement at the site of an epidermoid cyst combined with an acute, progressive neurological deficit should alert the treating physician to the possibility of a malignant transformation. When transformation does occur, the clinical and radiological course is quite aggressive as compared with the indolent growth of epidermoid cysts. Treatment options include surgery with adjuvant chemotherapy or radiotherapy. We review the pertinent features of this case along with the relevant literature regarding primary intracranial squamous cell carcinomas.

Traumatic haematomas located in the posterior fossa are less frequent than those above the tentorium. Extradural haematomas are the most common type of haematomas in the posterior fossa and are usually unilateral. We present the case of a patient with a bilateral extradural haematomas of the posterior fossa and review eight cases previously reported in the literature.

A rare case of unilateral benign essential tremor is presented that responded to surgical excision of a posterior fossa arachnoid cyst.

A series of 16 children (nine males, seven females) with traumatic epidural haematoma of the posterior fossa (TEHPF) is presented. All patients had a history of mild to moderate trauma to the occiput. The causes were falls in 15 and traffic accident in one case. Four of the 16 cases had depressed fractures of the occipital bone. Surgical intervention was performed in all cases. In 14 patients the outcome was good, one patient had moderate disability and one died. Our study revealed that early diagnosis and urgent surgical intervention may give the patient a chance of total recovery and craniotomy with haematoma evacuation is an appropriate surgical technique as in the case of supratentorial extradural hematoma.

Seeding on surgical pathway is a rare form of clival chordoma treatment failure. We report the case of a 42-year-old male with a clival chondroid chordoma removed by a sublabial transsphenoidal approach followed by proton beam radiotherapy, who developed a maxillary bone recurrence 3 years after surgery.