Duraplasty in the posterior fossa using a boat-shaped sheet of expanded polytetrafluoroethylene.
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Application of sutures between expanded polytetrafluoroethylene (ePTFE) dural substitutes and the dura mater is often frustrating in posterior fossa surgery because of the difficulty in holding the elastic graft in a deep and narrow field. To resolve this problem, we have developed a boat-shaped graft made from a triangular ePTFE sheet by pinching each angle using a suture. Formation of standing edges of the sheet facilitates holding of the flaps for secure and more rapid suturing than the conventional approach using a flat sheet. (+info)
Dural arteriovenous fistula involving the posterior condylar canal.
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Although dural arteriovenous fistulas (DAVFs) occur in any structure that is covered by the dura mater, DAVFs at the posterior condylar canal have not been reported. We present a DAVF that involves the posterior condylar canal and drains into the posterior condylar vein and the occipital sinus, which was treated by selective transvenous embolization. Knowledge of venous anatomy of the craniocervical junction and careful assessment of the location of the arteriovenous fistula can contribute to successful treatment. (+info)
Screw fixation via diploic bone paralleling to occiput table: anatomical analysis of a new technique and report of 11 cases.
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Several types of posterior approaches have been adopted for occipitocervical fusion. Prior to this study, Foerater et al. in 1927 used a fibular strut graft in the site between the occiput and the lower cervical spine to achieve fusion. Since then, various techniques including wrings, Hartshill loop, AO reconstructive plate, and AXIS occipital plate were described and used widely. As far as we know, all these techniques involve the screw placement vertical to the diploic bone; however none has ever addressed the feasibility of screw placement in occiput parallelling to the diploic bone. In our study, 30 dry specimens of human occiputs were measured manually using vernier calipers and protractors. The intradiploic screw was first supposed to be inserted inferiorly to the superior nuchal line (SNL) prominence. The entry point located at the superior edge of the SNL prominence. Afterward, the measurements of extracranial occiput in SNL area on midline and bilateral 15 mm to the midline saggital-cutting planes of the occiput were conducted. The thickness of the occipital bone at the location of SNL prominence, the entry point, the exit point and the screw orientation were measured, respectively. Afterward, 11 patients with craniocervical malformation were treated surgically using this alternative and their X-ray radiographs and CT scans were evaluated postoperatively. The data showed that the occipital at the site of SNL prominence was the thickest. The thickest point was external occipital protuberance (EOP), which was up to 14 mm. The thickness decreased gradually from the site of SNL to the superior border of surgical decompressed area. The actual length of screw channel was about 26 mm. The mean thickness for safe screw insertion ranged from 5.73 to 14.14 mm. A total of 22 intraocciput screws parallel to diploic bone were placed precisely, without injury to the cerebral and inner occipital venous sinus. The results confirm that occiput is available for holding intraocciput screw paralleling to diploic bone. (+info)
Retropharyngeal pseudomeningocele formation as a traumatic atlanto-occipital dislocation complication: case report and review.
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Retropharyngeal pseudomeningocele after atlanto-occipital dislocation is a rare complication, with only five cases described in the literature. It develops when a traumatic dural tear occurs allowing cerebrospinal fluid outflow, and it often appears associated with hydrocephalus. We present a case of a 29-year-old female who suffered a motor vehicle accident causing severe brain trauma and spinal cord injury. At hospital arrival the patient scored three points in the Glasgow Coma Scale. Admission computed tomography of the head and neck demonstrated subarachnoid hemorrhage and atlanto-occipital dislocation. Three weeks later, when impossibility to disconnect her from mechanical ventilation was noticed, a magnetic resonance imaging of the neck showed a large retropharyngeal pseudomeningocele. No radiological evidence of hydrocephalus was documented. Given the poor neurological status of the patient, with spastic quadriplegia and disability to breathe spontaneously due to bulbar-medullar injury, no invasive measure was performed to treat the pseudomeningocele. Retropharyngeal pseudomeningocele after atlanto-occipital dislocation should be managed by means of radiological brain study in order to assess for the presence of hydrocephalus, since these two pathologies often appear associated. If allowed by neurological condition of the patient, shunting procedures such as ventriculo-peritoneal or lumbo-peritoneal shunt placement may be helpful for the treatment of the pseudomeningocele, regardless of craniocervical junction management. (+info)
Linkage to chromosome 2q36.1 in autosomal dominant Dandy-Walker malformation with occipital cephalocele and evidence for genetic heterogeneity.
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Dumbbell-shaped intradiploic epidermoid cyst involving the dura mater and cerebellum.
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A 55-year-old woman presented with an epidermoid cyst extending to the cerebellum manifesting as headaches and pain in the left eye. Magnetic resonance imaging showed an intradiploic part with ring enhancement and an intracerebellar part. Intraoperative inspection revealed erosion of the occipital bone and defective dura mater. The tumor was located both epidurally and subdurally and the cyst consisted of pearly white keratin. The tumor was totally removed and the patient was discharged with no neurological deficit. The intradiploic part of the tumor formed the body and the intracerebellar part was caused by inflammatory reaction, which resulted in the atypical enhancement of the intradiploic part. (+info)
Endocranial occipito-temporal anatomy of SD-1219 from the Neandertal El Sidron Site (Asturias, Spain).
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Giant plexiform neurofibroma and suboccipital meningocele manifesting as segmental neurofibromatosis.
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A 34-year-old woman presented with segmental neurofibromatosis manifesting as a soft lump with a large cafe-au-lait macule on her occipital region and neck. Magnetic resonance imaging showed a thick skin tumor in the occipital region and posterior neck, and a suboccipital meningocele which seemed to have no association with her symptoms. Biopsy lead to a histological diagnosis of giant plexiform neurofibroma. During biopsy, massive local bleeding occurred and hemostasis was achieved by electrocautery and meticulous suture ligation. The postoperative course was uneventful and observation was continued for both the giant plexiform neurofibroma and the meningocele. (+info)