Emil Margolin

Results of endovascular treatment of traumatic intracranial aneurysms.

OBJECTIVETo present results of early angiographic diagnosis and endovascular treatment of traumatic intracranial aneurysms (TICA). METHODSFrom June 2002 to December 2006, diagnostic angiography was performed on patients with moderate to severe traumatic brain injury that involved a cranial base fracture or a penetrating brain injury with a tract from the penetrating agent that entered at the pterional area, went through the middle cerebral artery candelabra, and crossed the midline. TICAs were treated by various endovascular techniques during the same angiographic procedure. RESULTSThirty-four patients with traumatic brain injury underwent angiography (25 penetrating brain injuries, nine blunt injuries); 13 TICAs were diagnosed (10 penetrating brain injuries, three blunt injuries). The Glasgow Coma Scale score at diagnosis ranged from 5 to 15. Angiography was performed for screening in eight patients and for clinical indications in five patients; 11 TICAs were diagnosed before rupture. Seven aneurysms were located on branches of the middle cerebral artery, two on pericallosal branches of the anterior cerebral artery, and four on the internal carotid artery. No recanalization was detected in 12 patients. One patient treated with a bare stent and coiling had a growing intracavernous pseudoaneurysm; therefore, internal carotid artery occlusion with extracranial-intracranial microvascular bypass was performed. Six patients refused angiographic follow-up, but computed tomographic angiography has failed to show recanalization. No patient presented with delayed bleeding (mean follow-up, 2.6 yr). There were no procedure-related complications or mortality. CONCLUSIONEarly angiographic diagnosis with immediate endovascular treatment provided an effective approach for TICA detection and management. Endovascular therapy is versatile and offers a valuable alternative to surgery, allowing early aneurysm exclusion with excellent results.

Malignant transformation of a residual cerebellopontine angle epidermoid cyst

Malignant transformation is a rare but devastating complication following partial resection of an intracranial epidermoid cyst (EC). Time to malignant transformation is highly variable and optimal management is unclear. A literature search from 1965 to January 2016 identified manuscripts discussing clinical presentation, management, and outcome of malignant transformation of a remnant intracranial EC. One male patient diagnosed with malignant transformation of a remnant intracranial EC in our institution was also included in the study. There were 21 patients with malignant transformation of a remnant intracranial EC, including the current patient. Mean age was 51.4years (range 36 to 77) and there was a female predominance (12 women, 9 men, ratio 1.33:1). The mean time interval from partial resection of a benign intracranial EC to malignant transformation was 7.74years (range from 3months to 33years). Surgical resection of the tumor alone was the treatment of choice in 10 patients with one of them requiring a second operation and radiotherapy 2months following the first operation. Adjuvant treatment modalities were employed in 11 patients and included radiotherapy (n=4), stereotactic radiosurgery (SRS) (n=3), chemotherapy (n=1), chemotherapy combined with SRS (n=1) and with radiotherapy (n=1) and radiotherapy combined with SRS and followed by a second tumor resection (n=1). Follow-up period ranged from 1 day to 5years and 11/19 patients (57.8%) were reported dead on follow-up. Prospective studies are required to define the optimal management of malignant transformation of remnant intracranial EC.

Extraosseous aneurysmal bone cyst of cerebello-pontine angle with USP6 rearrangement

Aneurysmal bone cyst (ABC) is a benign cystic lesion characterized by blood filled cyst-like cavities separated by connective tissue septa containing spindle cells, osteoclasttype multinucleated giant cells and reactive woven bone or osteoid [7]. Most ABCs arise de novo (primary ABC), but others (secondary ABC) are associated with another benign or malignant bone lesion [7]. Most of the lesions are located within the metaphysis of long bones or vertebral bodies of children and young adults [7]. Involvement of cranial bones is not common, but well documented [2]. Giant cell reparative granuloma, which frequently occurs in the jaw bones, has been shown to be a solid variant of ABC [6]. Lesions that are entirely extraosseous or limited to soft tissues are extremely rare and only a few examples are reported in the English language literature [1, 3, 4, 8], none of them intracranial. We present a case of a primary intracranial extraosseous ABC located in the right cerebello-pontine angle (CPA) region of a 25-year-old man. The patient presented with headache, nausea, vomiting, vertigo and mild, right-sided hearing loss of 1 week duration. His past medical history was unremarkable. General physical examination and neurological examination were unremarkable, except for postural dizziness. Computerized tomography (CT) scan and magnetic resonance imaging (MRI) of the head (Fig. 1) revealed a solid-cystic contrastenhancing extra-axial mass in the region of the right CPA, superior and posterior to the internal auditory canal, measuring 3.3 cm in largest dimension, and causing a mass effect on the brain stem and compression of the fourth ventricle. Cranial bone involvement was not evident neither by CT scan nor by MRI. Under the presumptive preoperative diagnosis of a vestibular schwannoma, the patient underwent suboccipital craniotomy with gross total resection of the lesion. The lesion was tentorial-based and not connected to the skull. The intra-operative impression was that of a vascular malformation. Post-operative course was uneventful. 21 months following surgery, the patient is in good health, with no evidence of residua or recurrence. The specimen received for pathological examination consisted of irregular tan, rubbery, partially cystic tissue fragments, total volume 5 ml. Microscopic examination of paraffin sections revealed broad connective tissue septa consisting of spindle cells of variable cellularity, interrupted by partly anastomosing cavernous channels and cystic spaces, which were not lined by endothelial cells (Fig. 2a). Many of these channels and spaces contained blood or serum. Although the connective A. M. Oliveira, E. Margolin and J. M. Gomori made an equal contribution to this work.

Modified pterional craniotomy without “MacCarty keyhole”

Pterional craniotomy is one of the most widely used approaches in neurosurgery. The MacCarty keyhole has remained the preferred means of beginning the craniotomy to achieve a low access point; however, the bone opening may result in a residual defect and an aesthetically unpleasant depression in the periorbital area. We present our modification of the traditional technique. Instead of drilling the keyhole in the frontoperiorbital area, the classical location, we perform a 5 × 15 mm strip craniectomy at the lowest accessible point in the infratemporal fossa, corresponding to the projection of the most lateral point of the sphenoid ridge. The anterior half of this opening exposes the basal frontal dura, while the posterior half brings the temporal dura into view. This modified technique was applied in 48 pterional craniotomies performed for removal of a variety of neoplasms during 2014-2015. There were no approach-related complications. Aesthetic outcomes and patient acceptance have been good; no patient developed skin depression in the periorbital area. In our experience, craniotomy for a pterional approach with the lowest possible access to the frontotemporal skull base may be performed by drilling a narrow oblong opening, without the use of any keyhole or burr hole, to create a smaller skull defect and achieve optimal aesthetic outcomes.

Cerebellar liponeurocytoma in two siblings suggests a possible familial predisposition

There is limited data on the genetic origin and natural history of cerebellar liponeurocytoma. To the best of our knowledge there has been only one report of a familial presentation of this rare entity. We report a 72-year-old female with a posterior fossa tumor presenting with progressive cerebellar signs and symptoms. The patient underwent total tumor resection via an uncomplicated sub-occipital craniotomy. Histopathologic examination was diagnostic for cerebellar liponeurocytoma. Her sister was previously treated for a similar tumor. Our report provides further evidence for the possible existence of a hereditary abnormality predisposing afflicted families to cerebellar liponeurocytoma development.

Comparison of outcomes following complex posterior fossa surgery performed in the sitting versus lateral position

The sitting position during surgery is thought to provide important advantages, yet it remains controversial. We compared surgical and neurological outcomes for patients operated on in the sitting versus lateral position. Technically difficult procedures performed from the years 2001-2008 for complex lesions in the posterior fossa (vestibular schwannomas, other cerebellopontine angle tumors, foramen magnum meningiomas, brainstem cavernomas, pineal region tumors) were included. Outcomes in the two surgical positions were compared for all 243 patients (93 sitting, 38.3%; 150 lateral, 61.7%) and for 130/243 patients with vestibular schwannomas (50 sitting, 38.5%; 80 lateral, 61.5%). Sitting and lateral patient subgroups were clinically comparable. There were no surgical mortalities. The extent of removal and surgical and neurological outcomes were comparable. We found no advantage in surgical or neurological outcomes for use of the sitting or lateral surgical positions in technically difficult posterior fossa procedures. In vestibular schwannoma surgeries facial nerve preservation (House-Brackmann score 1-2) was related to extent of resection but not to surgical position. The choice of operative position should be based on lesion characteristics and the patients preoperative medical status as well as the experience and preferences of the surgeons performing the procedure.

Basilar artery dissection: A rare complication of posterior fossa epidermoid cyst resection, and evaluation of the possible effects of cerebrospinal fluid drainage on disease progression

We report a rare case of a 45-year-old female with an unruptured basilar artery dissecting aneurysm presenting with locked-in syndrome due to brainstem ischemia eleven months following resection of a giant cerebellopontine angle epidermoid cyst and three months after insertion of ventriculo peritoneal shunt due to hydrocephalus. The etiology of basilar artery dissection and the effect of hydrocephalus and ventricular cerebrospinal fluid drainage on disease progression in this patient are unclear. Our report suggests a possible effect of hydrocephalus and ventricular cerebrospinal fluid drainage on intracranial arterial dissection progression.

Author response: The essense of primum no nocere--striking a balance between benefit and harm

In fact, every issue raised in the editorial was carefully addressed in our paper, yet the authors ignored our discussion of these topics. We clearly presented all of the problems and risks concerning management of a recurrent atypical parasagittal meningioma in a patient with a history of radiation that had led to a very poor scalp condition. In addition, we described our extensive consultation with a team of experienced plastic surgeons and radiooncologists regarding treatment options. We also discussed the patient’s involvement in the decision-making process. He provided informed consent for the procedure with a complete understanding of the risks related to all treatment options as well as the novelty of the approach we suggested. Thus, the statement that, B... even worse, smaller snack-size innovations...may not even be presented to the patient as an ‘innovation’ ...^ was inappropriate. Today, endoscopic surgery is a well-established part of the neurosurgical armamentarium. Based on our experience, we felt that the tumor could be safely accessed using endoscopic techniques. With respect to the concept of Bpushing the envelope^ regarding the indications for the endoscopic approach, it is interesting to recall the strenuous efforts 20 years ago to obstruct early attempts to introduce these techniques into neurosurgical practice, given that they now represent the standard of care in an increasing range of clinical situations. In truth, we do not consider our procedure as a risky and radical technique. Venous hemorrhage from the superior sagittal sinus may be controlled much more easily than bleeding from damage to the internal carotid artery, which may occur during complex but increasingly routine endoscopic procedures. In fact, the endoscopic approach was considered and eventually recommended as the optimal technique in this situation precisely because of the principle of primum non nocere. After a careful weighing of the options by a highly experienced multidisciplinary team, we assumed that with standard calvarial craniotomy, with or without scalp transplant, our patient would face a high risk of infarcted scalp fall-off with life-threatening wound-healing complications due to his severe scalp atrophy. In our opinion, this risk far exceeded the risks associated with an endoscopic approach in his particular situation. We emphasize that open craniotomy remains the standard of care for the management of parasagittal meningiomas. * Sergey Spektor sergeyspektor@gmail.com