Christopher T. Melroy

A comparison of computer-aided surgery registration methods for endoscopic sinus surgery.

Background Stereotactic computer-aided surgery has provided the surgeon with a means to navigate more safely through diseased or surgically altered sinus anatomy. Accurate registration is vital to successful image-guided surgery. This study compared the accuracy and performance of three registration methods: fiducial, anatomic landmarks, and surface registration. Methods Ten fixed cadaveric heads underwent endoscopic computed tomography scan followed by middle meatal antrostomy and sphenoidotomy. Each registration method was performed, and the time required and mean registration error were recorded. Five anatomic sites were then identified and compared with the preoperative computed tomography images. The true distances between the known anatomic sites and the crosshair locations on the images were measured. Results Statistically significant differences were noted for mean registration error and time for registration. The mean ± SEM time for registration for the fiducial, surface, and landmark methods were 5 minutes 24 seconds ± 27 seconds, 1 minute 1 second ± 5 seconds, and 11 minutes 46 seconds ± 45 seconds, respectively. The mean ± SEM registration error for the fiducial, surface, and landmark methods were 0.48 ± 0.21 mm, 1.05 ± 0.06 mm, and 3.1 ± 0.25 mm, respectively. When the true accuracy of the three registration methods were compared, no significant difference was found between fiducial and surface registration. However, fiducial registration was significantly more accurate than landmark registration at all points. When compared with landmark registration, surface registration was statistically more accurate at all anatomic sites except for the sella turcica and optic nerve. Conclusion When the true accuracies of these methods were compared infixed cadaveric specimens, fiducial and surface registration were statistically similar but were found to be significantly more accurate than landmark registration. Furthermore, when time of registration, accuracy, and ease of use were considered, surface registration was found superior.

Concordance of middle meatal swab and maxillary sinus aspirate in acute and chronic sinusitis: a meta-analysis.

Background The medical management of acute and chronic sinusitis is a therapeutic challenge. The use of endoscopic middle meatal cultures as a noninvasive method to determine the bacteriology of the maxillary sinus has not accurately been established. The aim of this study was to review the literature that compares cultures obtained by endoscopic middle meatal swabs with those obtained from maxillary sinus aspirates (MSAs). Methods We reviewed studies published between January 1966 and October 2003 that were identified from searches of multiple databases, bibliographies, and original articles. Studies were included for analysis if they compared the results of endoscopic middle meatal cultures to aspirate cultures. All clinical variables and test performances were independently extracted by two reviewers. Results Middle meatal culture had a per isolate accuracy of 82% (95% confidence interval, 0.64, 0.92) compared with MSA (excluding coagulase negative staphylococcus and fungal cultures). Conclusion Endoscopic middle meatal cultures have a high concordance with MSAs.

Staged Endoscopic and Combined Open/Endoscopic Approach in the Management of Inverted Papilloma of the Frontal Sinus

Background The endoscopic management of inverted papilloma has gained increasing popularity over the last 10 years. Although early concerns over an increased risk of recurrence seem to have been allayed, the appropriate management of lesions involving the frontal sinus and frontal recess still has to be determined. Methods We performed a retrospective review of the results of all patients with inverted papilloma from 2000 to 2004. Results A total of 18 patients were treated between October 2000 and January 2004. Six patients had frontal sinus involvement at the time of initial evaluation. One of these patients had isolated frontal sinus involvement. These patients were managed with either initial endoscopic resection with determination for the need for an additional procedure at the time of endoscopic resection (n = 5) or open/endoscopic approach for isolated frontal sinus involvement (n = 1). Of the five patients who had their disease managed endoscopically, three patients were determined at the initial procedure to need an osteoplastic flap and, subsequently, were managed successfully with a combined approach. One other patient was initially successfully managed endoscopically but ultimately required an osteoplastic flap for definitive management. The fifth patient was managed entirely endoscopically with multiple procedures. All patients treated with this protocol remain disease free with an average follow-up of 13.3 months. Conclusion The limitations of endoscopic resection of inverted papilloma of the frontal recess can be managed with staged procedures. Initial endoscopic resection of ethmoid/maxillary disease with subsequent open treatment of the frontal sinus has been successful in our experience.

Endoscopically guided aerobic cultures in postsurgical patients with chronic rhinosinusitis

Background There is considerable amount of debate in the literature regarding the microbial flora of normal, acutely infected, and chronically infected paranasal sinuses. Few studies have specifically looked at the microbial flora of healthy and infected sinus cavities after functional endoscopic sinus surgery. Methods One hundred thirty-four cultures were studied. All cultures were obtained using a standard technique. The nasal cavities were decongested and anesthetized, and nasal endoscopy was performed. When purulent secretions were identified, specimens of purulent secretions were obtained for incubation. Sensitivities were tested according to microorganisms identified. Empiric therapy generally consisted of a fluoroquinolone, amoxicillin/clavulanate, or a later-generation cephalosporin, and adjustment in individual instances when appropriate. Results Twelve cultures showed no growth, 86 grew a single microorganism, and 35 grew two or more microorganisms for a total of 151 microorganisms identified. The most common microorganisms were Staphylococcus aureus, coagulase-negative staphylococci, and Pseudomonas aeruginosa. Other organisms that were cultured <5% of the time included Streptococcus pneumoniae, Haemophilus influenza, Moraxella catarrhalis, Serratia liquefaciens, Stenotrophomonas (Xanthomonas) maltophilia, alcaligenes, Fusobacterium, Escherichia coli, diphtheroids, Acinetobacter species, Klebsiella species, skin flora, and mixed Gram-negative and Gram-positives. Conclusion Endoscopically guided aerobic cultures in postsurgical patients with acute exacerbations of chronic rhinosinusitis most commonly grew S. aureus, coagulase-negative staphylococci, and pseudomonal species. These cultures altered antibiotic treatment management decisions in a significant number of cases regardless of patients’ clinical characteristics or history of previous culture.

Analysis of methods to assess frontal sinus extent in osteoplastic flap surgery: Transillumination versus 6-ft Caldwell versus image guidance

Background The aim of this study was to compare three common methods (transillumination, plain radiographs, and computerized tomography [CT] image guidance) for estimating the position and extent of pneumatization of the frontal sinus in osteoplastic flap surgery. Methods Axial CT scans and 6-ft Caldwell radiographs were performed on 10 cadaver heads. For each head, soft tissue overlying the frontal bone was raised and the anticipated position and extent of the frontal sinus at four points was marked using three common methods. The silhouette of the frontal sinus from the Caldwell plain radiograph was excised and placed in position. Four points at the periphery also were made using information obtained from a passive optically guided image-guided surgery device, and transillumination via a frontal trephination also was used to estimate sinus extent. The true sinus size was measured at each point and compared with experimental values. Results The use of CT image guidance generated the least difference between measured and actual values (mean = 1.91 mm; SEM = 0.29); this method was found statistically superior to Caldwell (p = 0.040) and transillumination (p = 0.007). Image guidance did not overestimate the size of the sinus (0/36) and was quicker than the Caldwell approach (8.5 versus 11.5 minutes). There was no learning curve appreciated with image guidance. Conclusion Accurate and precise estimation of the position and extent of the frontal sinus is crucial when performing osteoplastic flap surgery. Use of CT image guidance was statistically superior to Caldwell and transillumination methods and proved to be safe, reproducible, economic, and easy to learn.

Radiographic resolution of chronic rhinosinusitis without polyposis after 6 weeks vs 3 weeks of oral antibiotics

BACKGROUND Maximal medical therapy is poorly defined in chronic sinusitis treatment. OBJECTIVE To objectively evaluate the radiographic response of chronic rhinosinusitis without polyposis after 3 and 6 weeks of oral antibiotics. METHODS Thirty-five patients with confirmed chronic sinusitis without polyposis (disease apparent on initial computed tomography [CT] with appropriate symptom duration) were prescribed 6 weeks of antibiotics. When possible, culture-directed antibiotics were used; otherwise clindamycin was used empirically. A CT was performed after 3 and 6 weeks of therapy. CTs were then graded by the Lund-Mackay system. Demographic data were reviewed. RESULTS Of the 35 patients, 16 underwent all 3 CT scans and completed all 6 weeks of antibiotics. Three patients completed only 3 weeks of antibiotics, and 16 did not undergo the interval 3-week CT. Six patients (38%) had statistically significant improvement in their CT scans between weeks 3 and 6. In this subset of patients who improved, 37% of their overall radiographic improvement occurred in the 3- to 6-week treatment interval. No prognostic variables predicted which patients would radiographically improve after 3 weeks of antibiotics. CONCLUSION Some patients achieve radiographic improvement and disease resolution after the completion of a 3-week course of antibiotics. Therefore, maximal medical therapy for chronic sinusitis may consist of longer than 3 weeks of therapy to ensure maximal benefit.

Increased role of the otolaryngologist in endoscopic pituitary surgery: Endoscopic hydroscopy of the sella

Background The aim of this study was to discuss the use of nasal irrigation and suction systems in endoscopic pituitary surgery to examine the sella and facilitate tumor removal. We describe a new technique of sellar exploration. Methods Following the endoscopic approach to the pituitary by the otolaryngology team, pituitary masses are resected. Then, the ClearESS nasal irrigation and suction system is used by the otolaryngology team to visualize the sella (“hydroscopy”). The combination of this ClearESS technology and angled endoscopes is used to scrutinize previously inaccessible areas of the tumor bed. Results Over 50 patients have undergone minimally invasive pituitary surgery via the endoscopic approach with postresection hydroscopy of the sella. The use of angled endoscopes in combination with the ClearESS technology greatly increased visualization of the sella, thereby facilitating complete tumor removal. There have been no complications associated with the use of hydroscopy. Conclusion The use of angled endoscopes in conjunction with hydroscopy increases visualization of the sella. The otolaryngologist plays a critical role in this examination with manipulation of the angled endoscopes. Therefore, the role of the otolaryngologist is extended beyond the approach to the pituitary.

Safety of ethmoid sinus drug-eluting catheter insertion.

Objectives: We sought to evaluate an instrument that allows a drug-eluting catheter to be inserted into the ethmoid sinuses and to demonstrate its safety and reproducibility in a cadaver model. Methods: A drug-eluting catheter was placed into 12 cadaveric anterior and posterior ethmoid sinuses by use of a trocar-based insertion device. The devices position was analyzed with computed tomographic scans, and postprocedural dissection was performed. Results: The drug-eluting catheter system was successfully inserted in all ethmoid sinuses without injury to the medial orbital wall, skull base, or sphenoid face. The final position of the distal tip of the catheter averaged 8.1 mm (root mean square [RMS], 3.3 mm) from the skull base, 5.6 mm (RMS, 3.5 mm) from the sphenoid face, and 5.0 mm (RMS, 3.5 mm) from the lamina papyracea; the proximal tip was at the face of the ethmoid bulla and 17.1 mm (RMS, 3.5 mm) below the skull base. Conclusions: A trocar-based instrument can relatively safely and reproducibly introduce a drug-eluting catheter into the ethmoid sinuses without injuring the skull base, lamina papyracea, or sphenoid face. This device may allow safe topical drug delivery into the ethmoid sinuses and serve as a vehicle to treat chronic ethmoid sinusitis with direct and sustained topical therapy.

Multi-use venturi nasal atomizer contamination in a clinical rhinologic practice

Introduction Cross-contamination of Venturi atomizers has been reported. Methods In phase I, 16 atomizers were sterilized and refilled with either 1% lidocaine or 0.1% Tyzine (day 0). During phase II, atomizers were wiped with isopropyl alcohol wipes between uses. In both phases, on days 7, 14, 21, and 28, the contents of the atomizer were sprayed onto two culture media. If a culture was found positive, cultures from the nozzle, lumen, and solution were taken and cultured in depth. Results Twelve lidocaine bottles and three Tyzine bottles were initially positive. There were more positive cultures from lidocaine bottles than Tyzine bottles at 2 weeks (p = 0.02). After wiping with isopropyl alcohol, contamination was significantly reduced in the lidocaine bottles at 2 weeks (p = 0.02). Conclusion Microbial contamination of questionable clinical significance may occur with nasal atomizers. Regardless of this significance, wiping the devices with isopropyl alcohol can eliminate microbial growth for a 2-week interval.

Safety of Ethmoid Sinus Drug-Eluting Catheter Insertion

Problem The objective is to develop an instrument which allows a drug-eluting catheter to be safely and reproducibly inserted into the ethmoid sinuses. Methods A trochar-based insertion device was designed to allow delivery of a drug-eluting catheter into the anterior and posterior ethmoid sinuses. It was inserted into 12 cadaveric ethmoid sinuses under endoscopic and fluoroscopic guidance. CT scans were performed pre-, intra-, and post-procedure. The devices position was analyzed and the proximity to the skull base, lamina papyracea, and ethmoid face was measured. The specimens were then dissected and evaluated for skull base, sphenoid face, or lamina papyracea injury. Results The drug eluting catheter system was successfully inserted into the ethmoid sinuses of all 12 cadaver sides without injury to either the medial orbital wall or the skull base as confirmed by post-procedure CT scan and dissection. The final position of the distal tip of the stent averaged 8.1mm (RMS = 3.3) from the skull base, 5.6mm (RMS=3.5) from the sphenoid face, and 5.0mm (RMS=3.5) from the lamina papyracea; the proximal tip was at the face of the ethmoid bulla and 17.1mm (RMS=3.5) below the skull base. Conclusion This study demonstrates that a trochar-based instrument can safely and reproducibly introduce a drug-eluting catheter into the ethmoid sinuses without skull base or lamina papyracea injury. This device may allow safe topical drug delivery into the ethmoid sinuses and provide chronic ethmoid sinusitis patients an alternative to ethmoidectomy. Significance The primary surgical therapy for chronic ethmoid sinusitis is ethmoidectomy; topical therapy has been widely used in the management of chronic ethmoid sinusitis only after ethmoidectomy. This study shows a drug-eluting catheter can be safely and reliably inserted into virgin ethmoid sinuses in order to allow the topical elution of medications into the ethmoids without ethmoidectomy. Support Acclarent supplied cadaveric specimens.