Computer-aided frontal sinus surgery.

Computer-aided surgery technology supports computer-enabled review of CT images and intraoperative surgical anatomy. Many rhinologic surgeons have embraced computer-aided surgery for complicated frontal sinus procedures because computer-aided surgery may simplify these complex procedures. This article discusses the fundamental principles of computer-aided surgery, its limitations, and its application to frontal sinus surgery.

Revision endoscopic frontal sinusotomy with mucoperiosteal flap advancement: the frontal sinus rescue procedure.

Frontal sinusitis after middle turbinate resection occurs because of stenosis of the frontal ostium by soft tissue scarring or residual bony fragments (which are pulled to the medial orbital wall by scar contracture). Standard endoscopic techniques cannot address this problem; however, revision endoscopic frontal sinusotomy with mucoperiosteal flap advancement (the frontal sinus rescue procedure) relieves this bony stenosis and incorporates a mucosal flap that minimizes postoperative stenosis.

Leukotriene B4 levels in rabbit maxillary sinusitis: limitations of the current model.

Since the late 1980s, the rabbit model for sinusitis has been widely used for experimental studies on sinusitis; however, the clinical relevance of these experimental data has been questioned. To elucidate the role of leukotrienes in the pathogenesis of sinusitis, leukotriene B4 (LTB4) levels were determined in acute Streptococcus pneumoniae sinusitis in this model. The rabbit model for acute maxillary sinusitis was utilized. Briefly, the right maxillary ostium of each New Zealand white rabbit was occluded with cyanoacrylate under general anesthesia. Twenty-four hours after occlusion, the occluded sinus received an inoculation of 10(8) Streptococcus pneumoniae (ATCC 10813) or a sham inoculation of saline alone. Rabbits were then sacrificed one week later, and the maxillary sinus mucosae were harvested. Leukotriene B4 levels were determined by ELISA assay. LTB4 levels in the sinuses inoculated with bacteria tended to be higher; however, statistical analysis did not reveal significant differences between the experimental and control groups. It is possible to reliably assess leukotriene B4 levels in this model of sinusitis. Although the data suggest a trend for elevated LTB4 levels, statistical analysis did not support this conclusion. The study also demonstrated significant limitations in the current rabbit model for sinusitis; that is, the standard human sinus bacterial pathogens are minimally pathogenic in rabbit sinuses and the small size of the sinus limits the material available for assay. Further modifications of the model are necessary. After such adjustments, the role of leukotrienes in sinusitis may be further explored.

Comparison of Scientific Calipers and Computer-Enabled CT Review for the Measurement of Skull Base and Craniomaxillofacial Dimensions.

Traditionally, cadaveric studies and plain-film cephalometrics provided information about craniomaxillofacial proportions and measurements; however, advances in computer technology now permit software-based review of computed tomography (CT)-based models. Distances between standardized anatomic points were measured on five dried human skulls with standard scientific calipers (Geneva Gauge, Albany, NY) and through computer workstation (StealthStation 2.6.4, Medtronic Surgical Navigation Technology, Louisville, CO) review of corresponding CT scans. Differences in measurements between the caliper and CT model were not statistically significant for each parameter. Measurements obtained by computer workstation CT review of the cranial skull base are an accurate representation of actual bony anatomy. Such information has important implications for surgical planning and clinical research.

The frontal sinus rescue procedure: early experience and three-year follow-up.

The frontal sinus rescue (FSR), first described in 1997, has now been performed on 24 patients (32 sides) over a period of three years. It is a functional endoscopic surgical approach to correct an iatrogenically scarred and obstructed frontal recess, which cannot be successfully opened via a normal endoscopic frontal sinusotomy approach. It is utilized primarily for patients whose only remaining option is either a Draf-type drill-out (modified intranasal Lothrop) procedure or frontal sinus obliteration. The FSR is a technically challenging procedure, but faster, less difficult, and less destructive for the patient than a "drill-out" or frontal sinus obliteration. Once learned, it can save the patient from undergoing the more radical drill-out or obliterative procedure. The early experience and three-year follow-up with this new endoscopic procedure is presented in our first 24 patients (32 sides).

Image-guided functional endoscopic sinus surgery.

INTRODUCTION: Computer-aided surgery (CAS) technology in functional endoscopic sinus surgery (FESS) has engendered considerable discussion. OBJECTIVE: The goals of this study were to describe CAS preoperative planning (software-based CT image analysis) and to develop intraoperative CAS strategies for endoscopic sinus surgery. STUDY DESIGN: Between October 1, 1997, and December 31, 1998, the StealthStation (Sofamor Danek, Memphis, TN) was used in 61 FESS cases, and a retrospective review of the findings was performed. The indication for surgery in all instances was chronic rhinosinusitis refractory to medical management. The StealthStation was used to review all CT scans before surgery. Anatomic fiducial registration supplemented by contour mapping was used. RESULTS: Localization accuracy was estimated to be within 2 mm or better. The StealthStation was used for both CT image review and intraoperative localization. CAS was useful in the frontal recess, sphenoethmoid region, posterior ethmoid system, and skull base area. CAS was deemed helpful in situations where the surgical anatomy was altered by previous surgery and extensive inflammatory disease (polyposis, fungal sinusitis, and pansinusitis). CONCLUSION: The paradigm of image-guided FESS surgery, which integrates CAS into FESS, will serve to increase surgical effectiveness and decrease surgical morbidity.

Computer-aided assessment of bony nasal pyramid dimensions.

OBJECTIVE: To develop a computer-enabled paradigm for assessment of bony nasal pyramid dimensions. DESIGN: Retrospective review of archived computed tomographic data. SETTING: Tertiary level academic center. PATIENTS: Patients who had undergone computed tomographic scans for computer-aided transsphenoidal hypophysectomy were included. Previous nasal surgery, inflammatory sinus disease, and documented maxillofacial trauma were exclusion criteria. INTERVENTION: Archived computed tomographic scan images were reviewed using the software tools on a computer-aided surgical (CAS) system (StealthStation; Sofamor Danek, Memphis, Tenn). Standardized methods for the measurement of nasal bone thickness and bony nasal pyramid projection were established. MAIN OUTCOME MEASUREMENTS: Bony nasal pyramid projection and nasal bone thickness were determined. RESULTS: Computed tomographic scans from 8 patients were reviewed. Nasal bone thickness at the level of lateral osteotomy was 2.39 +/- 0.68 (mean + SD) mm, while nasal bone thickness at the level of intermediate osteotomy was 1.18 + 0.30 mm. Nasal projection from the nasomaxillary suture to the rhinion in the axial plane was 19.20 + 3. 10 (mean + SD) mm, while the corresponding nasal projection at the nasion was 20.61 + 3.52 mm. CONCLUSIONS: This brief report presents a new paradigm for the assessment of the bony nasal pyramid. Additional normative data are necessary. This information has important implications for rhinoplasty instrument design, surgical planning, and aesthetic assessment. It is likely that computer-enabled review of archived computed tomographic images for maxillofacial assessment will become increasingly accepted. Of course, further modifications of computer technology and its specific applications are expected.

The endoscopic management of chronic frontal sinusitis associated with frontal sinus posterior table erosion.

Expansile inflammatory diseases of the frontal sinuses may produce erosion of the posterior table of the frontal sinus. In these instances, the bone between sinus mucosa and intracranial dura is absent. Over the past decade, endoscopic frontal sinusotomy has emerged as the preferred technique for the treatment of refractory chronic frontal sinusitis. Endoscopic approaches also have a role in the most advanced instances of frontal sinusitis. A retrospective chart review of patients who were treated for frontal sinusitis with erosion of the frontal sinus posterior table was performed. Eight patients were identified. All patients underwent endoscopic frontal sinusotomy; some patients required multiple endoscopic procedures. Complete frontal recess dissection with identification of the frontal ostium was achieved for all involved frontal sinuses. In all cases, this postoperative result was monitored by CT scans (where indicated) and serial nasal endoscopy, which demonstrated good frontal sinus aeration and normal mucociliary clearance. Antibiotics were administered for culture-documented bacterial exacerbations, and systemic steroids were given for management of allergic fungal sinusitis and sinonasal polyposis associated with asthma. No patient underwent frontal sinus obliteration or cranialization. No suppurative intracranial complications were noted during the postoperative period. Endoscopic frontal sinusotomy can be used safely for the definitive management of frontal sinusitis associated with posterior table erosion. In fact, endoscopic techniques may represent the preferred approach for the treatment of this problem. Such an approach avoids the morbidity of more destructive alternatives (such as obliteration), and serves to create a frontal sinus with normal mucociliary clearance.

Acellular dermal allograft for sellar reconstruction after transsphenoidal hypophysectomy.

Obliteration of the sphenoid sinus using fat is often used after transsphenoidal hypophysectomy. The morbidity of this approach includes donor site complications, fat necrosis, and delayed mucocele formation. As obliteration with fat is intended to prevent cerebrospinal fluid (CSF) leakage, an alternative for this technique would be techniques used for CSF rhinorrhea repair. Instead of sinus obliteration, these defects are repaired with fascial autografts, which are unfortunately associated with donor site complications. To avoid sinus obliteration and donor site complications, we have reconstructed the sella with acellular dermal allograft in lieu of sinus obliteration. Transsphenoidal hypophysectomy was performed under combined microscopic and endoscopic visualization. For closure, the sellar anterior wall was reconstructed with acellular dermal allograft, septal cartilage/bone autograft, and fibrin glue. The sinus mucosa was then draped over the reconstruction and held in place with microfibrillar collagen hemostat slurry. The sphenoid sinus was not obliterated. Postoperatively, all patients underwent serial nasal endoscopy. Thirteen patients underwent the procedure as described for removal of pituitary adenoma. Postoperative discomfort and pain were minimal. Intraoperative CSF leaks were identified in five patients; none of these patients experienced a postoperative CSF leak. The microfibrillar collagen hemostat was cleared by sphenoid mucociliary clearance. One patient developed acute sphenoid sinusitis several weeks after surgery; this patient did not develop meningitis. One postoperative CSF leak occurred in an obese patient, in whom an intraoperative CSF leak was not identified; this leak resolved with bedrest and delayed lumbar drainage alone. Sellar reconstruction with acellular dermal allograft may eliminate the need for sphenoid sinus obliteration after transsphenoidal hypophysectomy. Acellular dermal allograft sellar reconstruction ultimately provides for an aerated, functioning sphenoid sinus without increased CSF leak risk or potential donor site morbidity.

Computer-aided surgical reduction of facial fractures.

The successful surgical treatment of facial fractures is based primarily on the spatial judgment of the surgeon, who may utilize occlusal and skeletal relationships to confirm adequacy of the reduction. Although computed tomography (CT) scans are helpful visual representations of the fractures, they cannot be used directly to guide the reduction. Currently the surgeon may extract an approximate measurement of displacement or defect size from a CT scan, but intraoperatively he must reduce a fracture or place an implant based on his best guess, using adjacent normal skeleton as landmarks. Computer-aided surgery (CAS) can be used to bridge the discontinuity between preoperative CT scan images and intraoperative facial fracture reduction. This article summarizes our experience with CAS applications in the treatment of facial fractures.

Endoscopically guided frontal sinus beclomethasone instillation for refractory frontal sinus/recess mucosal edema and polyposis.

Despite its metabolic complications, systemic corticosteroid therapy remains a mainstay in the treatment of refractory polyposis after endoscopic frontal sinusotomy. Furthermore, topical nasal corticosteroids often fail, presumably due to the relatively small dosage actually absorbed by the polyps. In order to minimize steroid complications while increasing the locally absorbed dose, beclomethasone (approximately 1 cc, 84 mcg/100 microliters) was instilled under endoscopic guidance directly into the frontal sinus in 31 instances in 16 patients with postoperative frontal recess/sinus polyposis and mucosal edema. The frontal recess/sinus polyposis/edema resolved completely in 9 frontal sinuses, improved considerably in 7 frontal sinuses, improved minimally in 5 frontal sinuses, and remained unchanged in 10 frontal sinuses. No complications were noted. AM cortisol levels remained in the normal range. Endoscopically guided frontal sinus beclomethasone instillation should be considered for the treatment of refractory postoperative frontal sinus/recess polyposis/edema. Further basic and clinical research into the pathophysiology of the nasal mucosa is also warranted.

Advances in postoperative care following functional endoscopic sinus surgery.

The ultimate success of functional endoscopic sinus surgery often is determined during the period of postoperative care. Final surgical results are greatly influenced by preoperative surgical planning and intraoperative decision-making. One goal of postoperative care includes the prevention of scar formation, such as middle turbinate collapse. Specific techniques include mucosal preservation, middle meatal spacer corticosteroids and culture-directed antibiotics.

Efficacy of transcutaneous computed tomography--guided fine needle aspiration biopsy in patients with laryngeal squamous cell carcinoma, probable failed radiation therapy, and negative transmucosal biopsies.

For patients with suspected recurrent/persistent laryngeal squamous cell carcinoma (SCC) after external beam radiotherapy (EBRT), routine transmucosal biopsies obtained during direct laryngoscopy may fail to reveal active carcinoma. We evaluated transcutaneous computed tomography-guided fine needle aspiration (CTGFNA) in three consecutive patients who had a persistently fixed true vocal fold after EBRT that had been administered for laryngeal SCC and who had multiple negative transmucosal laryngeal biopsies. All three CTGFNA biopsies were positive, but final pathology confirmed invasive SCC in only one of the three patients. Despite its theoretical advantages, CTGFNA in its present form requires further assessment and/or modification.

Hypervascular tumor of the buccal space in an adult as a late recurrence of juvenile angiofibroma.

We describe an adult patient with recurrent juvenile angiofibroma, which presented as a rapidly enlarging, hypervascular mass in the anterior part of the cheek. The case is unusual because of the extreme delay (greater than 30 years) and the anatomic location of the recurrence.

Videoendoscopic analysis of laryngeal function during laughter.

Although commonly encountered in all human cultures, laughter remains poorly understood. In order to examine laryngeal function during laughter, telescopic and fiberscopic videolaryngoscopy was performed on five subjects, who laughed in the different vowels, at various frequencies, and in several voice qualities. During laughter, the vocal folds were found consistently to undergo rhythmic abduction and adduction. At the end of these specific phonation tasks, all subjects were able to gain voluntary control of paramedian vocal fold positioning. This study defined laryngeal function during laughter. These results have important clinical implications. Voluntary vocal fold positioning has important applications in speech therapy for dysphonias, such as vocal fold nodules, in which the primary cause is vocal fold hyperadduction. Patients suffering from these hyperadductive dysphonias may be able to utilize laughter to correct them.

Endovascular therapy for the carotid blowout syndrome in head and neck surgical patients: diagnostic and managerial considerations.

PURPOSE: To review our institution's recent experience with patients with carotid blowout syndrome who were referred for emergency diagnostic angiography and endovascular therapy. METHODS: Eighteen consecutive patients who had had surgery for cancer of the head and neck and in whom carotid blowout syndrome had occurred were referred to our service in accordance with a standardized protocol. RESULTS: Twenty-three angiographic pathoetiologic conditions were diagnosed in the 18 patients; the majority of these were pseudoaneurysms involving various segments of the carotid system. Multiple lesions were detected in five patients. Most patients were treated by means of permanent balloon occlusion; in 8 patients with either multiple lesions or impending rupture requiring flap reconstruction, a composite permanent balloon occlusion of the affected carotid system was performed. Hyperacute hemorrhages were arrested in all cases. Hemorrhages reoccurred in 2 cases, and in 2 patients who had permanent balloon occlusion of the internal carotid artery, transient ischemic attacks occurred, which appeared to be related to temporary collateral reserve failure. No permanent neurologic complications ensued. CONCLUSION: Our recent experience with carotid blowout syndrome suggests that this clinical diagnosis represents a heterogeneous group of angiographic pathoetiologies that the physician should evaluate carefully before proceeding with endovascular therapy. Specific endovascular approaches depend on the pathoetiologic mechanism of active or impending hemorrhage and the urgency with which intervention is required.