Project description:ObjectiveDefine the indications and outcomes for subjects undergoing treatment utilizing the extended middle cranial fossa approach (EMCF).Study designRetrospective records review.SettingUniversity-based tertiary referral center.PatientsSubjects undergoing treatment of posterior cranial fossa (PCF) lesions.Intervention(s)EMCF exposure and treatment of the indicating PCF lesion.Main outcome measure(s)Demographic, audiometric, and cranial nerve functioning variables were assessed.ResultsThirty-five subjects who underwent an EMCF exposure were identified over a 12-year period. The most common indication was meningioma (18; 51%) followed by schwannomas (six, 17%), and vascular lesions (five, 14%). Preoperative cranial nerve complaints were common (32, 94%) as were objective cranial nerve abnormalities on physical examination (21; 60%). Preoperative audiometric data from subjects with hearing demonstrated good functioning including pure-tone average (PTA) (21.7 ± 15.6 dB HL) and word understanding scores (95.1 ± 7.4%). Most (34, 97%) subjects had intact facial nerve function. The average length of stay was 11.6 days (median = 9). Cranial neuropathies were common postoperatively with 27 (79%) subjects demonstrating some objective cranial nerve dysfunction, the most common of which was trigeminal nerve hypesthesia (21, 61.7%). Subjects with identifiable pre- and postoperative audiometric data and preoperative hearing demonstrated small declines in the four-tone average (16.2 dB) and word recognition scores (22.4%). Two subjects (6%) had new profound hearing loss postoperatively.ConclusionsThe EMCF approach can provide safe and effective exposure of the anterior PCF.
Project description:Ganglioglioma (GG) is an uncommon primary lesion of the central nervous system that is typically located supratentorially. There are only a few reports of GG arising from the cerebellum. To the best of our knowledge this is the first case of a cerebellar GG with supratentorial extension and a longstanding history before its recognition. In fact, this 29-year-old male presented with an 11-year history of intermittent headaches. A cranial computerized tomography (CT) performed at the onset of his complaints failed to reveal the tumor. After a particularly longstanding cephalalgic episode, the patient underwent a new CT scan that was also negative. However, magnetic resonance (MR) imaging of the brain revealed a space-occupying lesion in the right cerebellar hemisphere with extension to the level of the superior colliculi and pineal recess. The tumor was partially removed through a midline suboccipital craniotomy and supracerebellar approach. Pathological examination of the tumor showed composition of atypical ganglion cells and astrocytes, indicating the diagnosis of cerebellar GG. At last follow-up, 24 months after surgery, the patient reported a marked improvement of his clinical condition with significant reduction of intensity and frequency of the headache. The present report illustrates how cerebellar GG may remain undetectable by CT and may therefore present with a longstanding history and nonspecific signs and symptoms. MR investigation can lead to the proper diagnosis. Even after partial removal the prognosis remains good and remission of the symptoms may be achieved. In this article, we review the literature and summarize the current understanding of infratentorial GGs.
Project description:•The transorbital approach combining eyebrow incision and crescent-shaped craniotomy increases the surgical freedom to access the anterior and middle skull-base.•The technic allows the use of both endoscope and microscope.•The concept is at the crossroad between the supraorbital keyhole and endoscopic trans-orbital approach.
Project description:Background Rates of hearing preservation following surgery via middle fossa craniotomy in patients harboring tumors with unfavorable characteristics are significantly lower than for those patients with "favorable" tumors. Objectives We will present two cases both with unfavorable conditions, which underwent endoscopic-assisted middle fossa craniotomy (MFC) resection of intracanalicular vestibular schwannomas with preserved postoperative hearing. Methods Chart reviews were conducted on both patients. Their presentation, intraoperative details, and techniques, pre- and postoperative audiograms, and facial nerve outcomes are presented. Results Patient A had 5.6 × 6.8 × 13.2 mm intracanalicular tumor with unserviceable hearing (pure tone audiometry [PTA], 41; speech determination score [SDS], 47%; class D) but was blind so hearing preservation was attempted. Postoperative hearing was preserved (PTA, 47; SDS, 60%; class B). Patient B had a 5 mm round intracanalicular tumor immediately adjacent to the vestibule and cochlea without any fundal fluid present. Preoperative audiogram showed serviceable hearing (PTA, 48; SDS, 88%; class B). Postoperatively, aidable hearing was preserved (PTA, 51; SDS, 76%; class C). Conclusion Hearing preservation surgery via MFC can be enhanced with endoscopic-assisted dissection, especially in the lateral internal auditory canal. The superior optical view allows for preservation of cochlear nerve function and removal of residual tumor not otherwise seen on microscopy.
Project description:The classical middle cranial fossa approach (MCFA) for vestibular schwannoma (VS) removal often requires a large incision and craniotomy, excessive temporal lobe manipulation, and a longer recovery. We describe a keyhole MCFA (KMCFA) with endoscopic assistance that allows for adequate access with minimal temporal lobe manipulation, resulting in a fast recovery and an invisible scar. Eight sides of four cadaveric heads were dissected through the endoscopic-assisted KMCFA to access the internal auditory canal (IAC). Furthermore, five patients with intracanalicular VS underwent tumor removal with the endoscopic-assisted KMCFA. During the endoscopic-assisted KMCFA with fine instruments, a 3-cm supra-auricular incision and a 2-cm diameter keyhole craniotomy achieved exposure of the entire length of the IAC in all cadaveric dissections without unintended violation of the cochlea, semicircular canal, and facial nerve. The gross tumor was totally removed in five patients with no major postoperative complications. The surgical time was reduced, the hearing outcomes were similar to those of the classical MCFA, and the scar was invisible 1 month after the surgery. The endoscopic-assisted KMCFA permits intracanalicular VS removal in a safe, efficient, and cosmetic way. For small intracanalicular VSs, this approach can replace the classical MCFA when indicated.
Project description:Hydrocephalus occurs more often in brachycephalic individuals of different species. Detailed analysis of rostral cranial fossa-region of cerebrospinal fluid outflow-is necessary to understand causes leading to hydrocephalus in specimens with shortened skull. The objective of the study was to determine morphology and morphometry of rostral cranial fossa in brachycephalic dogs. Skulls of 126 dogs of different breeds and morphotypes were examined using computed tomography. Linear and volumetric measurement in the region of rostral cranial fossa and skull base were made. In brachycephalic dogs there is shortening of rostral cranial fossa which is linked with the volume reduction of this region. There are differences in skull base shape between brachycephalic dogs and other morphotypes. Similarities between brachycephalic dogs and patients with craniosynostoses were noted.
Project description:Background and purposeDAVFs rarely involve the sphenoid wings and middle cranial fossa. We characterize the angiographic findings, treatment, and outcome of DAVFs within the sphenoid wings.Materials and methodsWe reviewed the clinical and radiologic data of 11 patients with DAVFs within the sphenoid wing that were treated with an endovascular or with a combined endovascular and surgical approach.ResultsNine patients presented with ocular symptoms and 1 patient had a temporal parenchymal hematoma. Angiograms showed that 5 DAVFs were located on the lesser wing of sphenoid bone, whereas the other 6 were on the greater wing of the sphenoid bone. Multiple branches of the ICA and ECA supplied the lesions in 7 patients. Four patients had cortical venous reflux and 7 patients had varices. Eight patients were treated with transarterial embolization using liquid embolic agents, while 3 patients were treated with transvenous embolization with coils or in combination with Onyx. Surgical disconnection of the cortical veins was performed in 2 patients with incompletely occluded DAVFs. Anatomic cure was achieved in all patients. Eight patients had angiographic and clinical follow-up and none had recurrence of their lesions.ConclusionsDAVFs may occur within the dura of the sphenoid wings and may often have a presentation similar to cavernous sinus DAVFs, but because of potential associations with the cerebral venous system, may pose a risk for intracranial hemorrhage. Curative embolization through a transarterial or transvenous approach is the primary therapeutic strategy for these lesions. In incompletely embolized patients, exclusion of any refluxing cortical veins is necessary.
Project description:Acoustic neuromas are the most common lesion in the cerebellopontine angle. The authors report a unique case of acoustic schwannoma, presenting in middle cranial fossa masquerading as meningioma in a 24-year-old man, presenting with headache and focal seizures. Contrast-enhanced MRI of the brain revealed a mass lesion of the right middle cranial fossa consistent with features of meningioma. Intraoperatively a well-defined tumor with attachment to anterior petrous bone was excised. In the immediate postoperative period, the patient developed right-sided hearing loss, which was proven to be retrochoclear hearing loss on brainstem evoked response audiometry. Histopathology findings were consistent with benign schwannoma. Acoustic schwannoma originating in an unusual location middle cranial fossa is a plausible explanation of such unusual occurrence. Such a case has never been reported in the literature.
Project description:The anatomical features of the temporal bone can vary significantly among different individuals. These variations affect the operative view in middle cranial fossa surgery. We performed 18 middle fossa approaches in 9 cadaveric heads, with detailed morphological analysis, to identify unfavorable situations and reliable systems to avoid complications during surgery. We recorded linear, angular measurements and calculated areas. We performed a computed tomography (CT) scan with analysis of the amount of bone to remove in two temporal bones. We found that the location of the internal auditory canal (IAC) is the keystone of bone removal. We also found accuracy in the system suggested by E. and J. L. Garcia-Ibanez for its identification and that there is a smaller surgical window in female patients (statistically significant) that can be predicted on preoperative imaging studies. Our study also confirms significant individual variability in the mutual relationships of different surgical landmarks. We concluded that surgery of the middle fossa requires detailed understanding of the complex temporal bone anatomy. The surgeon has to be aware of extreme variability of the more commonly used anatomical landmarks. The method to identify the position of the IAC described by E. and J. L. Garcia-Ibanez seems to be the simplest and most reliable. When the surgical strategy includes an anterior petrosectomy, interindividual variability can critically affect the working area, particularly in females. The working area can be estimated on preoperative CT scans through the petrous bone.
Project description:Background and purposeMiddle cranial fossa encephaloceles are an increasingly recognized cause of epilepsy; however, they are also often encountered on neuroimaging in patients with no history of seizure. We characterized the MR imaging features of middle cranial fossa encephaloceles in seizure and nonseizure groups with the hope of uncovering features predictive of epileptogenicity.Materials and methodsSeventy-seven patients with middle cranial fossa encephaloceles were prospectively identified during routine clinical practice of neuroradiology at a tertiary care hospital during an 18-month period. Thirty-five of 77 (45%) had a history of seizure, 20/77 (26%) had temporal lobe epilepsy, and 42/77 (55%) had no history of seizures. Middle cranial fossa encephalocele features on MR imaging were characterized, including depth, area, number, location, presence of adjacent encephalomalacia, and degree of associated parenchymal morphologic distortion. MR imaging features were compared between the seizure and nonseizure groups.ResultsNo significant difference in MR imaging features of middle cranial fossa encephaloceles was seen when comparing the seizure and nonseizure groups. Comparison of just those patients with temporal lobe epilepsy (n = 20) with those with no history of seizure (n = 42) also found no significant difference in MR imaging features.ConclusionsAnatomic MR imaging features of middle cranial fossa encephaloceles such as size, number, adjacent encephalomalacia, and the degree of adjacent parenchymal morphologic distortion may not be useful in predicting likelihood of epileptogenicity.