Embargoed until May 11, 2001
Contact: Kenneth S. Satterfield760-776-8502 (5/11-5/16) 703-519-1563[email protected]
Image-Guided Technology Is Found Essential for Safe and Effective Endoscopic Sinus Surgery of the Sphenoid Sinus
The sphenoid sinus is located near a number of neurovascular structures. Image-guided technology provides a clear road-map for complex surgery for chronic sinusitis
Palm Desert, CA -- More than 37 million Americans are believed to have chronic sinusitis. Most find relief with a regimen of antibiotics. However, a sizable number must undergo endoscopic sinus surgery, a procedure most commonly performed by otolaryngologist÷head and neck surgeons.
The advent of endoscopic techniques and modern imaging modalities has revolutionized the surgical approaches to the posterior-ethmoid sinuses since the introduction of computed tomography (CT) and magnetic resonance imaging (MRI) scans in the 1980s. While these advances were revolutionary, they still had inherent deficiencies, which limited their value in the management of complicated sinus surgical procedures. With the introduction of computer-aided image guidance in 1993, the endoscopic view and the CT view have been united to provide a three-dimensional triplanar perspective to the surgical anatomy.
Computer-aided imaging can be invaluable in crucial anatomic regions such as the sphenoid sinus, which is bordered by sensitive neurovascular structures. The sphenoid sinus, located in the recessed position in the skull base and surrounded by a host of vital neurologic structures, may be amenable to image-guided surgery in both primary and revision surgical cases. Laterally, the sphenoid sinus is flanked by the cavernous sinus, which houses the oculomotor nerve, the trochlear nerve, the ophthalmic division of the cranial nerve and the internal carotid artery.
Generally, the sphenoid sinus may be accessed by two principal methods: bicoronal craniotomy or transnasal (through the nose) entry. The former approach is obviously fraught with many inherent risks and expected post-operative problems such as brain retraction and possibly permanent anosmia. Transnasally, the sphenoid can be approached either directly through the nasal vault, via a complete ethmoidectomy, or via a transeptal approach (such as the one used in hypophysectomy or surgical removal of the compound gland suspended from the base of the hypothalamus by a short extension of the infundibulum or pituitary stalk).
Researchers set out to demonstrate that the anatomy of the paranasal sinuses constitutes a complex three-dimensional structure that deserves the accurate spatial representation afforded by computer-aided image-guided endoscopic sinus surgery to avoid surgical pitfalls. Six cases were examined in this study.
The authors of the study, Computer-Aided Image-Guided Endoscopic Sinus Surgery in Unusual Cases of Sphenoid Disease, are Samuel M. Lam, MD, Department of Otolaryngology-Head & Neck Surgery, Columbia University College of Physicians & Surgeons, and Clark Huang, MD, and Vijay K. Anand, MD, Department of Otorhinolaryngology, Joan & Sanford I. Weill Medical College of Cornell University, all from New York, New York. Their findings were presented on May 14, 2001 at the spring meeting of American Rhinologic Society, held in Palm Desert, CA.
Methodology: Researchers utilized the InstaTrak, an armless, frameless surgical navigation system that relies on electromagnetic signaling. The device runs on a Sun SPARC computer using a Solaris operating system. All patients underwent preoperative CT scans recorded at 3-mm intervals in the axial plane and reconstructed at 1 mm for triplanar (axial, coronal, sagittal) presentation. Informed consent for the use of the InstaTrak system was obtained in all patients. Initial intraoperative calibration was performed with the suction-tip sensor in 4 directions according to the InstaTrak protocol.
Cases presented to the researchers consisted of: (1) oblique intersinus septum & failure to enter the correct sinus; (2) avoidance of onodi cell; (3) meningoencephalocele with csf leak; (4) meningoencephalocele with csf leak; (5) inverting papilloma of the sphenoid sinus; and (6) sphenoid mucocele after pituitary and endoscopic sinus surgery.
Results: Computer-aided image-guided endoscopic surgery proved to be essential in providing successful treatment in each of the six cases presented. When the surgical field has been distorted by prior surgery, inflammation, or disease, computer guidance becomes indispensable for safety. The sphenoid sinus, with the extensive neurovascular structures that encircle it, is benefited from this technology in primary and revision cases, as illustrated in the six cases presented.
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