Temporal bone dissection simulation--an update.

We report on our continued development of a virtual simulation for temporal bone dissection that provides stereoscopic display, haptic feedback, and aural simulation into a straightforward, comprehensive learning environment. The multimodal interface provides a seamless simulation for non-deterministic drilling and cutting of bone in the surgical context, as well as an intuitive interface for the intelligent tutor for learning regional anatomy. We present novel methodologies for integrating multimodal and multiresolution data sets, including extension to functional and structural segmentation. We will present our initial efforts to validate this environment. Through continued iterations, it is our hope that the system will provide a valuable tool for training future otologic surgeons as well as an environment for the quantitative evaluation of surgical skill.

Virtual temporal bone dissection simulation.

We have developed a working prototype system for the virtual simulation of temporal bone dissection. The system offers a paradigm from traditional practices by integrating technological advances to provide a safer and more cost effective way to learn fundamental techniques used in temporal bone surgeries. We present our methods to provide a real-time interactive volumetric system that obviates the need for physical materials in initial training, and provides a more accessible way for residents to practice and to increase exposure to pathological variance. Finally, we discuss ways to extend this work to more advanced resident training, presurgical planning, and surgical documentation.

Preliminary results on the management of unruptured intracranial aneurysms with magnetic resonance angiography and computed tomographic angiography.

OBJECTIVE: The goal was to assess the capability of magnetic resonance angiography (MRA) and computed tomographic angiography (CTA) to replace catheter angiography in the evaluation of unruptured intracranial aneurysms. METHODS: A prospective evaluation of a 1-year period included all patients suspected of harboring unruptured intracranial aneurysms at a single institution. All patients underwent magnetic resonance imaging, MRA, and CTA, for comparison with intraoperative findings or results from catheter angiography. Both MRA and CTA now provide submillimeter resolution of vascular structures, with accurate detection of intracranial aneurysms of a diameter greater than or equal to 3 mm. This resolution calls into question the universal need for catheter angiography in the care of patients with suspected intracranial aneurysms. When the catheter angiography can be avoided, radiological costs can be reduced by as much as two-thirds while eliminating the risk of arterial injury and stroke. RESULTS: Excellent visualization of the intracranial vasculature was provided by both MRA and CTA. No vascular lesion was detected at surgery or by formal angiography that was not visualized by noninvasive angiographic techniques. The three-dimensional anatomy of the aneurysm complex (unavailable with catheter angiography) was well depicted by both MRA and CTA. CTA was unique in its capacity to display the relationship of vascular structures to bone, information that is invaluable for planning operative strategies for lesions such as carotidophthalmic artery aneurysms. Additionally, acquisition of CTA images was very rapid, with a scanning time of less than 1 minute. Both MRA and CTA allowed for retrospective manipulation of data into an infinite number of views, including views that paralleled those encountered through the operative microscope. Additionally, both MRA and CTA can depict the internal anatomy of aneurysms, an ability not possessed by intra-arterial angiography. This ability alerts the surgeon to possible intraoperative risks, such as plaque in the lumen of an aneurysm or calcium within the walls of the arteries. CONCLUSION: Both MRA and CTA provide several advantages over digital subtraction angiography, in addition to reduced costs and avoidance of arterial injury and stroke. These include retrospective manipulation of data in a 360-degree format, visualization of the internal anatomy of arteries and aneurysms, three-dimensional depiction of anatomy, and rapid data acquisition. Preliminary data and a review of the literature suggest that MRA, when used in concert with CTA, can replace catheter angiography in the assessment of select patients harboring unruptured intracranial aneurysms. Although no firm conclusions or generalizations can be drawn from this small cohort of patients, it is hoped that this report will stimulate interest and further study at other institutions.

A new method for inserting the atrial end of a ventriculoatrial shunt. Technical note.

This technical note describes a simple percutaneous mechanism for placement of the atrial end of ventriculoatrial shunts. The method is fast, efficient, and involves no neck dissection. No special equipment is required. Placement involves the technique of central line insertion familiar to all surgeons. This new method has been used successfully in one adult and one pediatric patient.

Traumatic intracavernous aneurysm in children: massive epistaxis without ophthalmic signs.

Traumatic intracavernous aneurysms are a distinctly uncommon lesion in children. They usually present with compressive symptoms of the III, IV, V, or VI cranial nerves rather than epistaxis. Epistaxis is rare and usually minor and brief in duration. A child with severe head injury and basal skull fracture, who did not have any preceding symptoms or signs of ophthalmoplegia or exophthalmus, developed massive epistaxis as a leading symptom of the ruptured intracavernous aneurysm. Since there are no reported pediatric cases with fatal epistaxis as a presenting sign, we would like to share our experience.