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Chromoendoscopy Associated With Endoscopic Laryngeal Surgery: A New Technique for Treating Recurrent Respiratory Papillomatosis
Chromoendoscopy Associated With Endoscopic Laryngeal Surgery: A New Technique for Treating Recurrent Respiratory Papillomatosis Daniel G. Rey Caro, Enrique P. Rey Caro, and Enrique A. Rey Caro, Cordoba, Argentina Summary: Outline. Chromoendoscopy is a dye enhancement technique that uses epithelial tissue dyeing for assessing any changes in it by determining its characteristics and eventually to improving mucosal lesions detection at endoscopy. Currently with the addition of a joint use of rigid endoscopes and video systems at surgery, visualization of the larynx and trachea areas significantly improved with wide angle viewing. However, in certain diseases, such as laryngeal papillomatosis, certain conditions were overlooked by these approaches and with the likelihood of postoperative early relapse. With the addition of chromoendoscopy to endoscopic laryngeal surgery, we were able to increase the ability to recognize intraoperatively inconspicuous lesions, improve lesion limit visualization, observe in detail their surfaces, and determine as well the existence of residual lesion if any after surgical removal. Objectives. To prove the helpfulness of chromoendoscopy in otolaryngology as an innovative diagnostic technique associated with laryngeal endoscopical surgery. Materials and Methods. The present study uses contrast dyeing agents such as indigo carmine as endoscopic tissue staining and, incidentally, which is the most widely used detection method in gastroenterology. The dye fills the interstices, highlighting irregularities, such as depressions and elevations in architecture. Results. This diagnostic enhancing technique was used with six patients who presented recurrent laryngeal papillomatosis. We committed ourselves to get the most out of the intraoperative diagnostic yield and reduce the relapse likelihoods in all cases. Conclusion. Chromoendoscopy joined with endoscopic laryngeal surgery is an excellent intraoperative diagnostic approach in the management of laryngeal invasive conditions such as laryngeal papillomatosis. Key Words: Chromoendoscopy–Endoscopy–Endoscope–Intraoperative–Dyeing–Staining–Indigo carmine–Larynx– Epithelial–Papilloma–Papillomatosis–Respiratory–Surgeries–Diagnosis–Pathology–Relapse–Rigid endoscope.
INTRODUCTION The usual technique of removal of papillomas of the larynx and trachea consists in using an optical microscope under general anesthesia (GA), surgical instruments, and the Kleinsasser Technique.1 Currently, with the combination of rigid endoscopes and video systems, the visualization of the larynx and trachea significantly improved with wide angle viewing. However, under certain conditions, such as recurrent respiratory papillomatosis (RRP), certain lesions might be overlooked under optical microscopy with the possibility of early postoperative recurrence. Chromo-endoscopy is a technique that uses the application of stains (dyes) to assess epithelial changes, tissue characteristics, and is used to improve diagnosis of mucosal lesions during endoscopy.2 On its integration with the RRP surgical technique, we were able to detect lesions early, thus reducing the chances of recurrence by reducing the number of affected anatomical sites in the larynx and trachea. In recent years, interest in chromo-endoscopy has greatly increased because it is simple, cost-effective, and without potential risks. This technique gained prominence using edge Accepted for publication February 17, 2014. From the ENT Service of Chutro Clinic, Cordoba, Argentina. Address correspondence and reprint requests to Daniel G. Rey Caro, Clınica Chutro, Av Colon 788, C ordoba (5000), Cordoba, Argentina. E-mail: [email protected] Journal of Voice, Vol. -, No. -, pp. 1-8 0892-1997/$36.00 Ó 2014 The Voice Foundation http://dx.doi.org/10.1016/j.jvoice.2014.02.006
endoscopes, for example, use of magnification endoscopy in gastroenterology.3,4 Currently, the major clinical use of dyes in gastroenterology is for the diagnosing of Barrett’s esophagus, stomach, and esophagus carcinoma; differentiation of neoplastic and nonneoplastic colorectal lesions, among others.2–6 No side effects, neither anaphylactic events, have been reported with topical application of dyes into the mucosa. It has been mentioned the occurrence of anaphylactic reactions, cardiac arrest, and bronchospasm after intravenous administration in urological practice.7 The aim of this study was to demonstrate the usefulness of chromoendoscopy in otolaryngology, during endoscopic surgery of the larynx, for the detection of unsuspected papilloma that might go overlooked with conventional surgical techniques, such as microsurgery. Direct vision and microscopy, during surgery for papilloma in larynx or trachea, often times would not be suitable for detecting superficial or small lesions, for instance throughout the early stages of papillomavirus infection. That is why we would suggest the use of intraoperative chromoendoscopy as an innovative, valuable, and effective method for treating papilloma virus infection. Besides it is a valuable tool as well in correctly differentiating a lesion type because contrast dying helps determine the exact macroscopic limit, thus promoting local control, maximum preservation of the structures of the vocal folds, and improving postoperative functional outcomes.
2
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TABLE 1. Dyes used in chromoscopy are classified based on its interaction with the mucosa9 Dyes Absorption (vital)
Reactive
Contrast
Tattoo
Mucosal Interaction Enter the cell through diffusion or absorption through the cell membrane. Interact with certain substances in the cell producing distinctive color changes. Are not absorbed, such as indigo carmine and cresyl violet when impregnate slopes, elevations, and depressions of the mucous surface area provide enhanced topographic views. Provide long-lasting stains when injected into the mucosa
On the other hand, through the magnification rendered from rigid endoscopes, lesions can be studied by analyzing the architecture of the mucosal surface and eventually come to the suspect ion of the presence of malignancy. Chromoendoscopy applied to RRP would determine a possible correlation between a given appearance of a papillary pattern and a type of virus. Further studies are needed to confirm a relationship. Dr Shin-ei Kudo established a classification of mucosal patterns of the lesions due to pathological changes it undergoes when it is modified by various neoplastic,
inflammatory, or scar tissue contingencies. His work was performed in the field of gastroenterology.8 After surgical resection, chromoendoscopy facilitates further detection of residual lesions and their immediate removal. This is a common setting found in respiratory papillomatosis where the involvement of multiple areas affecting the larynx and trachea makes their complete removal difficult and even leaving untreated lesions therefore enabling unwanted relapses. Chromoscopy was used only during larynx surgery and not as an in office follow-up procedure; nonetheless, in papillomatosis of pharynx, chromoscopy is indeed useful for the tracking of lesions as an office routine. From our review of the literature, the present publication appears to be the first description of the use of contrast dyeing for detecting conditions such as RRP in the aerodigestive tract. MATERIALS AND METHODS This study was conducted between December 2005 and December 2011 in the Otorhinolaryngology Center of the Clinica Chutro in Cordoba, Argentina. During this period of time, 11 patients (two children and nine adults), with a presumptive diagnosis of RRP, had endoscopic and microscopic laryngeal surgery associated with chromo-endoscopy. Informed consent was obtained from all patients before their enrollment in the study. All the subjects underwent outpatient preoperative endoscopic examinations, previous 4% lidocaine topical spraying. Fiber-optic laryngoscopy or laryngeal telescopes were used. The extent of each lesion was carefully determined, digitally recorded, and subsequently analyzed with the aid of a custom
FIGURE 1. Recurrent respiratory papillomatosis. Microscopy with a 400 mm optical zoom lens makes possible the viewing of the larynx only in its vertical axis (Photo A); this is a wide-angle view of the larynx with a 30 telescope (Photo B); the use of chromoendoscopy allows observing real extent of laryngeal papillomatosis involving difficult to treat areas such as the anterior-commissure infrapetiole region (Photo C). Laryngeal papillomas at a closer look appear to be separate sessile masses, of different sizes, like a blanket covering the endolarynx. Villi and papillary lacunar pattern of the lesion (arrow) can be clearly observed and the difference between the healthy (i) and sick tissue (ii) is easily noted as well (Photo D).
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Chromoendoscopy Associated With Endoscopic Laryngeal Surgery
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FIGURE 2. Detailed view of the papillary pattern in respiratory papillomatosis: lacunar papillary pattern (see arrow in Photo A). A closer view of another patient’s microscopic study showed a lesion with a warty appearance, nodular, and irregular, with a starry papillary pattern typically red or pink (see arrow in Photo B); a fusiform papillary pattern (see arrow in Photo C). A view of combination of fusiform and winding patterns (see arrows Photo D). (For interpretation of references to color in this figure legend, the reader is referred to the web version of this article.) made computer program, which renders photographs of the lesion to be displayed in the operating room (OR). Before and after 2 months of surgery, all patients were treated with daily antacid therapy, Lansoprazole (15 mg for children) and Omeprazole (40 mg for adults). Prolonged antacid use was established as needed according to symptoms. All patients underwent chromo-endoscopy associated with endoscopic laryngeal surgery under GA in OR. After the patient was anesthetized, intubated, and the suspension laryngoscope inserted, we surveyed the field of surgery seeking for any abnormal condition. We carried out this procedure by first using an optical microscope and then rigid
endoscopes, which were both connected to a camcorder to record live images. After that, the laryngotracheal mucosa was conditioned for chromoscopy by washing it with some saline solution and with some mucolytic agents such as N-acetylcysteine (NAC) afterward, to remove traces of secretions usually found on the mucosal surface. After its careful aspiration preventing a mucosal bleeding, 1.5 to 2.0 mL indigo carmine dye was applied using an instillation needle. This procedure may be repeated as many times as needed according to the development of the surgical procedure. There is a difference between washed and unwashed-vocal
FIGURE 3. View of the mucosal lesion in the anterior supraglottic region that had been overlooked at microlaryngoscopy using a 30 telescope (see arrow in Photo A). A small 3 mm wart corresponding to a residual papilloma virus was identified using chromoendoscopy (arrow Picture B).
4
FIGURE 4. Papillomatosis of a ventricle and right ventricular band is shown. Two different stages of the lesion: one is superficial incipient and erythematous (a) and the other one is arborescent at a close view (b). folds as far as an endoscopic effectiveness concerns because mucus or blood may stand in the way and would impede dye insertion throughout the mucosa and wart folds, and, therefore, the use of mucolytic agents is required. Dyes used in chromoscopy are classified based on its interaction with the mucosa9: Table 1. In this research task, we worked with some contrast dyes such as indigo-carmine, which is the most widely staining procedure used for instance in gastroenterology. This stain is applied over the epithelium surface resulting in color highlighting of areas of irregular surface morphology for localization of laryngeal and tracheal papillomas. Furthermore, they can be seen in three dimensions. At the time of surgery, we used a powdered presentation of Indigo Carmine (Acid Blue 74 for microscopy from Anedra S. A. Laboratory in Argentina), which was diluted in normal saline to a final approximate concentration of 0.4%. (Indigo carmine, or indigotine, is an indigo derivative that is also used as a colorant. Natural indigo was obtained from those in the genus Indigofera. Carmine also called Crimson Lake, Cochineal, Natural Red 4, [1] C.I. 75470, [1] or E120, is a pigment of a bright-red color obtained from the aluminum salt of
Journal of Voice, Vol. -, No. -, 2014
carminic acid, which is produced by some scale insects, such as the cochineal scale and the Polish cochineal.) After dye instillation, the remainder of the staining fluid was immediately carefully aspirated and angulation endoscopes were properly positioned. We explored, with suitable equipment occult or difficult-totreat areas such as the subglottic region, trachea, ventricular region, and anterior commissure and we were able to correctly identify papilloma sites, their edges, and features of their surface. We also looked for lesions highly suspicious for malignancy and the presence of small or isolated superficial lesions, which might have easily been overlooked and eventually become areas of elevated risk for future relapse.10 We used a Light 150 by Minicomp and a Sometech Dr. Oppel ST-501 radiofrequency (RF) surgical unit to remove papillomas. A set of electrodes with different tips for the removal of lesions was specifically designed to reach those difficult areas of the larynx and trachea. This device and its design were invented by the authors of this article. It is currently Patent Pending (RCMAE is patent pending. Patent application #20130100879 for RCMAE (Rey Caro Multi-Angle Electrode) has been filed (19/03/13) at the INPI patent office of Argentina (Instituto Nacional de Propiedad Industrial y Administraci on Nacional de Patentes de la Republica Argentina)) as RCMAE (Rey Caro Multi-Angle Electrode). The RCMAE functions with surgical units which comply with the Guidelines for Human Exposure to RF—for medical devices. At this stage, isolated shots of RF were performed at the low intensity ‘‘Coag’’ mode setting for achieving the most superficial effect on the mucosal surface to reducing to a minimum any tissue damage and thus avoiding a possible stenosis. After removal of the anterior commissure lesions, we topically applied 0.4 mg/mL Mitomycin C for 5 minutes to prevent adhesions formation.11 No adverse reactions were observed with neither the use of the dyeing or with Mitomycin C. RESULTS Endoscopic resection of the lesions was performed under GA in OR, and it did not require any special technique further than that of the formulation of the staining and its instillation with a suitable needle.
FIGURE 5. Image of endolaryngeal respiratory papillomatosis. A suspected supraglottic lesion is here seen with a 30 telescope (see arrows Photo A). The presence of a papillomatous superficial flat lesion of well-defined boundaries is accurately determined by using indigo carmine (see arrows Photo B).
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Chromoendoscopy Associated With Endoscopic Laryngeal Surgery
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FIGURE 6. Laryngeal vocal fold papillomatosis, ventricle, and right ventricular band (arrows Photo A). The lesion here is safely acknowledged as a papilloma lesion using chromoendoscopy. It presents a well-defined arborescent area with villi of different shapes and sizes, and it has a warty appearance (see arrows in Photo B).
The average time to complete a careful inspection per patient took roughly 3-5 minutes, according to the length and complexity of the affected areas. At the end of surgery, about the same time was employed again to double check that no residual lesions remained. All the images, obtained during surgery, from different regions such as the supraglottic, glottic, and subglottic were recorded using a digital video recorder. Diagnostic accuracy for respiratory papillomatosis was confirmed on the basis of histological studies. Moderate dysplasia was observed in two patients. Keratosis was found in two patients and there was glottic carcinoma in one patient. In general, under chromoscopy, all papillary lesions were sharply recognized because they had well-demarcated areas. Multiple warty-looking, arborescent, vegetative, or in clusters lesions were scattered over a wide area of the larynx. Other papillomas were observed as flat superficial, localized, erythematous, or small lesions, which were in many cases and many times difficult to recognize using regular microlaryngoscopy (Figures 1, 2, 4–6; Table 2). As we were able to observe in detail the superficial architecture of the papillomatous (villous) surface depicting different contours and sizes we derived, therefore, a papillary pattern TABLE 2. Preoperative and postoperative diagnosis Patients PK RMJ BR NS GF GM CF PC PR FE SJ
Preoperative Diagnosis P P P P P P P P P Papillomatosis vs carcinoma P
Sex Age (y) F M M F M F M M M
15 30 39 53 43 16 33 27 2 65
M
32
Abbreviations: P, papillomatosis; M, male, F, female.
Postoperative Diagnosis P. Mild Atypia P P. Keratosis P. Mild Atypia P P P. Keratosis P P Epidermoid carcinoma P
according to their vascular connective axis which is notable for its morphology: some lacunar (Figure 2, photo A and Figure 1, photo D), starry (Figure 2, photo B) or fusiform (Figure 2, photo C) or combination of spindle-shaped and winding patterns (Figure 2, photo D). Comparing chromo-endoscopic vision with that one obtained using a surgical microscope, in the latter method too many lesions smaller than 2 mm could not be spotted due to their small width. On the contrary, larger lesions could be recognized by both methods. Chromoendoscopy was however more suitable to recognize superficial lesions, and it showed very clearly and with great sharpness all the vegetant lesions and their edges (Figures 3 and 4). In one patient, we identified by indigo carmine two lesions of different morphology. A fully widespread flat lesion at the level of the right supraglottis with well-differentiated boundaries from the rest of the healthy larynx and similarly we properly delimited the boundary of a vegetant papilloma at the level of the glottis and right ventricular band. This condition allowed us making a safe resection of it and therefore preserving the healthy mucosa. The residual dye observed on the supraglottic area belongs to the filling of the cavities lying between the mucosal folds (Figures 5 and 6). At a 24-hour postoperative checkup, a slight edema and scar tissue on RF treated areas were observed in all the patients. In five, the anterior glottis was topically treated with 0.4 mg/mL of Mitomycin C for 5 minutes at the end of the surgical procedure to avoid synechia formation.11 On the sixth postoperative day, granulation tissue formation involving the anterior commissure was observed in one adult patient with a previous history of multiple surgeries for recurrent glottic papillomas. Such a formation was mechanically removed with hyssop under local anesthesia and indirect laryngoscopy in the outpatient therapeutic care room. No adverse reactions were observed with the dye or with Mitomycin C. All patients improved their voice quality after the surgical procedure. Late on the course of this study, we included a last patient who had a preoperative differential diagnosis of glottic carcinoma versus laryngeal papillomatosis. We could exactly define the border of the lesion and differentiate it from a papilloma by analyzing the superficial
6 TABLE 3. Papillary Pattern Classification Fusiform pattern
Winding pattern
Starry pattern
Lacunar pattern
Unstructured pattern (neoplastic)
architecture of the tumor during surgery. Anecdotal observation: the authors observed disorganization of the surface without grooves, no villi, and loss of the vascular pattern of the papilloma (Table 3). Additionally, leukoplakic areas, prominent capillaries, granularity, and erythroplakia surrounding the lesion were identified, which led us to an in vivo anatomical (not
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histological) presumption of dysplasia or malignancy and a diagnosis of glottic carcinoma was subsequently confirmed by anatomic pathology (Figure 7).12,13 DISCUSSION RRP is a benign laryngeal neoplasm most commonly found in childhood. More than 70 types of human papillomavirus have been described.13 Human papillomavirus serotypes 6 and 11 are generally associated with laryngeal disease and affects both sexes and ages.14 Various treatments have been proposed; however, resection is considered the most effective method.15 The current method for removing laryngeal papillomas is their ablation with tweezers and the use of different kind of lasers in conjunction with the conventional microsurgical technique, performed under GA either by orotracheal intubation or jet ventilation. Although the disease is almost always benign, it is common for patients to require repeat surgery. Although the use of laser in recent years has been integrated into microsurgery with adjuvant, intralesional Cidofovir injections have helped reduce the number of reoperations.16–18 These methods have not been adequate, in some patients, to keep RRP under control. The discovery of small superficial lesions is a clear benefit associated with chromoendoscopy. For instance, incipient wart-like lesions are generally seen as mucosal elevations or erythematous areas under microscopic view. If such a lesion is identified, then the next step is to apply some contrast dye. If a lesion is less than 3 mm and is clearly delineated, and it has a papillary pattern on its surface, we proceed to its removal with RF (Figure 8). We could detect minimal lesions by incorporating chromoendoscopy to the endoscopic surgical procedure for PRR, get better visualization of lesion edges, and preserve healthy mucosa during surgery. This method allows the recognition of suspected malignancies and an in vivo detection of residual lesions at postoperative follow-up appointments. Intraoperative lesions of subjects with RRP, which had been overlooked during initial microscopy, were later detected using chromoendoscopy. In our series, chromoendoscopy helped increase the sensitivity compared with that one of the conventional method. Loss of anatomical landmarks and difficulty in
FIGURE 7. Differential diagnosis of malignancy: left vocal fold carcinoma. Prominent capillaries surrounding the lesion are here seen under low chromo-endoscopic vision (Photo A), granularity, leukoplakic surface, loss of papillary pattern, and a disorganization of the capillary pattern all that which led us to the in vivo anatomical (not histological) presumption of dysplasia or malignancy (Photo B).
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Chromoendoscopy Associated With Endoscopic Laryngeal Surgery
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NBI) according to the first published studies would increase the chances of early detection of neoplastic lesions. This technology increases the diagnostic capability of endoscopes equipped with narrow-band filters (red, green, and blue bands) consists of a sequential electronic endoscope system and a source of light, yielding very clear images of the mucosal surfaces. Superficial lesions are identified by the changes in color, tone, and irregularity of the mucosal surface during endoscopic examinations. Their visual effect is similar to that one of chromoendoscopy.20
FIGURE 8. Here, the right ventricular band papillomatous superficial lesion measures about 3 mm. Contrast-chromoendoscopy evidences the edge between the papilloma and the healthy tissue. Under microscope, this lesion is only seen as a slight irregularity of the mucosal surface. This early papilloma could be hardly distinguished from an inflammatory or non-specific lesion by microscopy. fully exposing the anterior commissure might lead to an incomplete lesion resection and its local relapse. We treated papillomas with RF in hard-to-observe complex areas such as ventricles and subglottic region which were discovered with the help of 30 and 45 angled endoscopes. Histologically respiratory papillomas are composed of a vascular connective tissue core covered by stratified squamous epithelium with little or no tendency to invade submucosal tissues.13 Indigo carmine provides excellent visualization of mucosal abnormalities and subepithelial capillaries. We are able to define a papillary pattern on the basis of the vascular connective axis with chromoscopy during surgery. This is an important benefit hardly obtained by the regular illumination of endoscopes or surgical microscopes. In our research work, we identified at least four well-defined papillary patterns: lacunar, starry-sky, winding, and fusiform. In most patients, we observed that papillomatous lesions have two or three of the papillary patterns mentioned. Manuel Penaloza-Plascencia et al, in a study of 47 children demonstrated by analysis of viral DNA, co-infection with two or more types of virus in 74% of patients, and in the remaining 26% only one virus type was found.14 The presence of different papillary patterns on the same lesion would lead to conclude, on the basis of this research work, that each pattern would correspond to a definite type of virus, all that which could be confirmed in further studies in the future (Table 3). The first reports on the use of dyes in otolaryngology date back to the days of the work of Andrea Mario and Oscar Dias in Lisbon, Portugal. They defined specific patterns of epithelial cells using contact endoscopy in chronic laryngitis, keratosis, dysplasia, papillomas, and other malignancies. Contact endoscopy during microlaryngoscopy allows in vivo and in situ examination of previously methylene blue -stained epithelial layers.19 Then again, new endoscopic methods for diagnosis such as images obtained with narrow band light (Narrow-band imaging,
CONCLUSION Chromoendoscopy associated with endoscopic laryngotracheal surgery could increase the sensitivity for detection of small superficial lesions hardly visualized by means of traditional methods, and it could also play an important role in the diagnosis and treatment of respiratory mucosal diseases such as RRP. Tests with different dyes, such as those ones used in gastroenterology, guarantee a promising future of this technique in the early detection of lesions lying in the respiratory mucosa. The institution of chromoendoscopy associated with laryngeal or tracheal endoscopic surgery could significantly change diagnostic and surgical strategies for the treatment of RRP. RRP may possibly be detected at an early stage using this staining method and hence it would allow a curative resection. In short, the use of chromoendoscopy in RRP is useful for detecting lesions observed during preoperative endoscopic examinations, improving lesion border visualization, preserving healthy endolaryngeal mucosa (by differentiating between healthy from diseased tissue), allowing a detailed observation of surfaces lesion (to establishing differential diagnoses, ie, suspicion of a malignant lesion) and assessing the presence of residual injuries in vivo (intraoperative procedure). AWARDS ‘‘Prof. Dr. Juan Carlos Arauz’’ First Prize for ‘‘A new technique for treating recurrent respiratory papillomatosis using chromoendoscopy associated with Endoscopic Laryngotracheal Surgery (ELS)’’ research paper—granted by the Argentine Society of Otolaryngology and Children Phonoaudiology—at the IX Argentinian Congress of Pediatric Otolaryngology and Children Phonoaudiology during the III IAPO** Regional Meeting, Cordoba, May 24, 2007. **International Alliance of Patients’ Organizations. REFERENCES 1. Kleinsasser O. Endolaryngeal microsurgery. In: Techniques and Typical Atlas Images. 2nd ed. Editorial Cientifico-medica; 1978. 2. De Rezende L, Parra-Blanco A. Usefulness of chromoendoscopy as an auxiliary method of colonoscopy. Gastr Latinoam. 2005;16:192–204. 3. Sharma P, Weston AP, Topalovski M, Cherian R, Bhattacharyya A, Samplinier RR. Magnification chromoendoscopy for the detection of intestinal metaplasia and dysplasia in Barrett’s esophagus. Gut. 2003;52:24–27. 4. Sano Y, Saito Y, Fu L-I, Matsuda T, Uraoka T. Efficacy of magnifying chromoendoscopy for the differential diagnosis of colorectal lesions. Dig Endosc. 2005;17:105–116.
8 5. Ribeiro MD. Chromoendoscopy for early diagnosis of gastric cancer. Eur J Gastroenterol Hepatol. 2006;18:831–838. 6. Kiesslich R, Neurath MF. Chromo and magnifying endoscopy for colorectal lesions. Eur J Gastroenterol Hepatol. 2005;17:793–801. 7. Gousse A, Safir M, Madjar S, Ziadlourad F, Raz S. Life-threatening anaphylactoid reaction associated with indigo carmine intravenous injection. Urology. 2000;44:271–272. 8. Kudo S, Hirota S, Nakajima T, et al. Colorectal tumors and pitt pattern. J Clin Pathol. 1994;47:880. 9. Marin R, Gil MV, Castilian MM, Alvarez C, Belda O. Review of the clinical application of the dye in chromoendoscopy digestive and compounding. Farm Hosp. 2006;30:112–119. 10. Rey Caro EP, Rey Caro DG, Rey Caro EA. Laryngeal endoscopic surgery (VATS laryngeal microsurgery by telescopes) method for visualization of lesions with difficult access. Revista de la Sociedad Argentina de Otorrinolaringologıa. 2006;2:69–73. 11. Roh J-L, Yoon Y-H. Prevention of anterior glottic stenosis after transoralmicroresection of glottic lesions previous involving commissure with mitomycin C. Laryngoscope. 2005;115:1055–1059. 12. Jako GJ, Kleinsasser O. Endolaryngeal micro-diagnosis and microsurgery. Reprinted from de Annual Meeting of the American Medical Association; 1966.
Journal of Voice, Vol. -, No. -, 2014 13. Benjamin B. Multiple respiratory papillomas. London, UK: Endolaryngeal Surgery; 1998. 14. Penaloza-Placencia M, Montoya-Fuentes H, Flores-Martinez SE, Fierro Velasco FJ, Penaloza-Gonzalez JM, Sanchez-Corona J. Molecular identification of 7 human papillomavirus types in recurrent respiratory papillomatosis. Arch Otolaryngol Head Neck Surg. 2000;126:1119–1123. 15. Zeitels SM, Sataloff RT. Phonomicrosurgical resection of glottal papillomatosis. J Voice. 1999;13:123–127. 16. Mandell DL, Arjamand EM, Kay DJ, Casselbrant ML, Rosen CA. Intralesional cidofovir for pediatric recurrent papillomatosis. Arch Otolaryngol Head Neck Surg. 2004;130:1319–1323. 17. Pransky SM, Brewster DF, Magit AE, Kearns DB. Clinical update on 10 children treated with intralesional cidofovir injection for severe recurrent respiratory papillomatosis. Arch Otolaryngol Head Neck Surg. 2000;126:1239–1243. 18. Seth M, Magit AE, Kearns DB, Kang DR, Duncan NO. Intralesional cidofovir for recurrent respiratory papillomatosis in children. Arch Otolaryngol Head Neck Surg. 1999;125:1143–1148. 19. Andrea MD, Dias O, Santos. Contact endoscopy of the vocal cord: normal and pathological patterns. Acta Otolaryngol. 1995;115:314–316. 20. Watanabe A, Tsujie H, Taniguchi M, Hosakawa M, Fijita M, Sasaki S. Laryngoscopic detection of pharyngeal carcinoma in situ with narrowband imaging. Laryngoscope. 2006;116:650–654.
INTRODUCTION The usual technique of removal of papillomas of the larynx and trachea consists in using an optical microscope under general anesthesia (GA), surgical instruments, and the Kleinsasser Technique.1 Currently, with the combination of rigid endoscopes and video systems, the visualization of the larynx and trachea significantly improved with wide angle viewing. However, under certain conditions, such as recurrent respiratory papillomatosis (RRP), certain lesions might be overlooked under optical microscopy with the possibility of early postoperative recurrence. Chromo-endoscopy is a technique that uses the application of stains (dyes) to assess epithelial changes, tissue characteristics, and is used to improve diagnosis of mucosal lesions during endoscopy.2 On its integration with the RRP surgical technique, we were able to detect lesions early, thus reducing the chances of recurrence by reducing the number of affected anatomical sites in the larynx and trachea. In recent years, interest in chromo-endoscopy has greatly increased because it is simple, cost-effective, and without potential risks. This technique gained prominence using edge Accepted for publication February 17, 2014. From the ENT Service of Chutro Clinic, Cordoba, Argentina. Address correspondence and reprint requests to Daniel G. Rey Caro, Clınica Chutro, Av Colon 788, C ordoba (5000), Cordoba, Argentina. E-mail: [email protected] Journal of Voice, Vol. -, No. -, pp. 1-8 0892-1997/$36.00 Ó 2014 The Voice Foundation http://dx.doi.org/10.1016/j.jvoice.2014.02.006
endoscopes, for example, use of magnification endoscopy in gastroenterology.3,4 Currently, the major clinical use of dyes in gastroenterology is for the diagnosing of Barrett’s esophagus, stomach, and esophagus carcinoma; differentiation of neoplastic and nonneoplastic colorectal lesions, among others.2–6 No side effects, neither anaphylactic events, have been reported with topical application of dyes into the mucosa. It has been mentioned the occurrence of anaphylactic reactions, cardiac arrest, and bronchospasm after intravenous administration in urological practice.7 The aim of this study was to demonstrate the usefulness of chromoendoscopy in otolaryngology, during endoscopic surgery of the larynx, for the detection of unsuspected papilloma that might go overlooked with conventional surgical techniques, such as microsurgery. Direct vision and microscopy, during surgery for papilloma in larynx or trachea, often times would not be suitable for detecting superficial or small lesions, for instance throughout the early stages of papillomavirus infection. That is why we would suggest the use of intraoperative chromoendoscopy as an innovative, valuable, and effective method for treating papilloma virus infection. Besides it is a valuable tool as well in correctly differentiating a lesion type because contrast dying helps determine the exact macroscopic limit, thus promoting local control, maximum preservation of the structures of the vocal folds, and improving postoperative functional outcomes.
2
Journal of Voice, Vol. -, No. -, 2014
TABLE 1. Dyes used in chromoscopy are classified based on its interaction with the mucosa9 Dyes Absorption (vital)
Reactive
Contrast
Tattoo
Mucosal Interaction Enter the cell through diffusion or absorption through the cell membrane. Interact with certain substances in the cell producing distinctive color changes. Are not absorbed, such as indigo carmine and cresyl violet when impregnate slopes, elevations, and depressions of the mucous surface area provide enhanced topographic views. Provide long-lasting stains when injected into the mucosa
On the other hand, through the magnification rendered from rigid endoscopes, lesions can be studied by analyzing the architecture of the mucosal surface and eventually come to the suspect ion of the presence of malignancy. Chromoendoscopy applied to RRP would determine a possible correlation between a given appearance of a papillary pattern and a type of virus. Further studies are needed to confirm a relationship. Dr Shin-ei Kudo established a classification of mucosal patterns of the lesions due to pathological changes it undergoes when it is modified by various neoplastic,
inflammatory, or scar tissue contingencies. His work was performed in the field of gastroenterology.8 After surgical resection, chromoendoscopy facilitates further detection of residual lesions and their immediate removal. This is a common setting found in respiratory papillomatosis where the involvement of multiple areas affecting the larynx and trachea makes their complete removal difficult and even leaving untreated lesions therefore enabling unwanted relapses. Chromoscopy was used only during larynx surgery and not as an in office follow-up procedure; nonetheless, in papillomatosis of pharynx, chromoscopy is indeed useful for the tracking of lesions as an office routine. From our review of the literature, the present publication appears to be the first description of the use of contrast dyeing for detecting conditions such as RRP in the aerodigestive tract. MATERIALS AND METHODS This study was conducted between December 2005 and December 2011 in the Otorhinolaryngology Center of the Clinica Chutro in Cordoba, Argentina. During this period of time, 11 patients (two children and nine adults), with a presumptive diagnosis of RRP, had endoscopic and microscopic laryngeal surgery associated with chromo-endoscopy. Informed consent was obtained from all patients before their enrollment in the study. All the subjects underwent outpatient preoperative endoscopic examinations, previous 4% lidocaine topical spraying. Fiber-optic laryngoscopy or laryngeal telescopes were used. The extent of each lesion was carefully determined, digitally recorded, and subsequently analyzed with the aid of a custom
FIGURE 1. Recurrent respiratory papillomatosis. Microscopy with a 400 mm optical zoom lens makes possible the viewing of the larynx only in its vertical axis (Photo A); this is a wide-angle view of the larynx with a 30 telescope (Photo B); the use of chromoendoscopy allows observing real extent of laryngeal papillomatosis involving difficult to treat areas such as the anterior-commissure infrapetiole region (Photo C). Laryngeal papillomas at a closer look appear to be separate sessile masses, of different sizes, like a blanket covering the endolarynx. Villi and papillary lacunar pattern of the lesion (arrow) can be clearly observed and the difference between the healthy (i) and sick tissue (ii) is easily noted as well (Photo D).
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FIGURE 2. Detailed view of the papillary pattern in respiratory papillomatosis: lacunar papillary pattern (see arrow in Photo A). A closer view of another patient’s microscopic study showed a lesion with a warty appearance, nodular, and irregular, with a starry papillary pattern typically red or pink (see arrow in Photo B); a fusiform papillary pattern (see arrow in Photo C). A view of combination of fusiform and winding patterns (see arrows Photo D). (For interpretation of references to color in this figure legend, the reader is referred to the web version of this article.) made computer program, which renders photographs of the lesion to be displayed in the operating room (OR). Before and after 2 months of surgery, all patients were treated with daily antacid therapy, Lansoprazole (15 mg for children) and Omeprazole (40 mg for adults). Prolonged antacid use was established as needed according to symptoms. All patients underwent chromo-endoscopy associated with endoscopic laryngeal surgery under GA in OR. After the patient was anesthetized, intubated, and the suspension laryngoscope inserted, we surveyed the field of surgery seeking for any abnormal condition. We carried out this procedure by first using an optical microscope and then rigid
endoscopes, which were both connected to a camcorder to record live images. After that, the laryngotracheal mucosa was conditioned for chromoscopy by washing it with some saline solution and with some mucolytic agents such as N-acetylcysteine (NAC) afterward, to remove traces of secretions usually found on the mucosal surface. After its careful aspiration preventing a mucosal bleeding, 1.5 to 2.0 mL indigo carmine dye was applied using an instillation needle. This procedure may be repeated as many times as needed according to the development of the surgical procedure. There is a difference between washed and unwashed-vocal
FIGURE 3. View of the mucosal lesion in the anterior supraglottic region that had been overlooked at microlaryngoscopy using a 30 telescope (see arrow in Photo A). A small 3 mm wart corresponding to a residual papilloma virus was identified using chromoendoscopy (arrow Picture B).
4
FIGURE 4. Papillomatosis of a ventricle and right ventricular band is shown. Two different stages of the lesion: one is superficial incipient and erythematous (a) and the other one is arborescent at a close view (b). folds as far as an endoscopic effectiveness concerns because mucus or blood may stand in the way and would impede dye insertion throughout the mucosa and wart folds, and, therefore, the use of mucolytic agents is required. Dyes used in chromoscopy are classified based on its interaction with the mucosa9: Table 1. In this research task, we worked with some contrast dyes such as indigo-carmine, which is the most widely staining procedure used for instance in gastroenterology. This stain is applied over the epithelium surface resulting in color highlighting of areas of irregular surface morphology for localization of laryngeal and tracheal papillomas. Furthermore, they can be seen in three dimensions. At the time of surgery, we used a powdered presentation of Indigo Carmine (Acid Blue 74 for microscopy from Anedra S. A. Laboratory in Argentina), which was diluted in normal saline to a final approximate concentration of 0.4%. (Indigo carmine, or indigotine, is an indigo derivative that is also used as a colorant. Natural indigo was obtained from those in the genus Indigofera. Carmine also called Crimson Lake, Cochineal, Natural Red 4, [1] C.I. 75470, [1] or E120, is a pigment of a bright-red color obtained from the aluminum salt of
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carminic acid, which is produced by some scale insects, such as the cochineal scale and the Polish cochineal.) After dye instillation, the remainder of the staining fluid was immediately carefully aspirated and angulation endoscopes were properly positioned. We explored, with suitable equipment occult or difficult-totreat areas such as the subglottic region, trachea, ventricular region, and anterior commissure and we were able to correctly identify papilloma sites, their edges, and features of their surface. We also looked for lesions highly suspicious for malignancy and the presence of small or isolated superficial lesions, which might have easily been overlooked and eventually become areas of elevated risk for future relapse.10 We used a Light 150 by Minicomp and a Sometech Dr. Oppel ST-501 radiofrequency (RF) surgical unit to remove papillomas. A set of electrodes with different tips for the removal of lesions was specifically designed to reach those difficult areas of the larynx and trachea. This device and its design were invented by the authors of this article. It is currently Patent Pending (RCMAE is patent pending. Patent application #20130100879 for RCMAE (Rey Caro Multi-Angle Electrode) has been filed (19/03/13) at the INPI patent office of Argentina (Instituto Nacional de Propiedad Industrial y Administraci on Nacional de Patentes de la Republica Argentina)) as RCMAE (Rey Caro Multi-Angle Electrode). The RCMAE functions with surgical units which comply with the Guidelines for Human Exposure to RF—for medical devices. At this stage, isolated shots of RF were performed at the low intensity ‘‘Coag’’ mode setting for achieving the most superficial effect on the mucosal surface to reducing to a minimum any tissue damage and thus avoiding a possible stenosis. After removal of the anterior commissure lesions, we topically applied 0.4 mg/mL Mitomycin C for 5 minutes to prevent adhesions formation.11 No adverse reactions were observed with neither the use of the dyeing or with Mitomycin C. RESULTS Endoscopic resection of the lesions was performed under GA in OR, and it did not require any special technique further than that of the formulation of the staining and its instillation with a suitable needle.
FIGURE 5. Image of endolaryngeal respiratory papillomatosis. A suspected supraglottic lesion is here seen with a 30 telescope (see arrows Photo A). The presence of a papillomatous superficial flat lesion of well-defined boundaries is accurately determined by using indigo carmine (see arrows Photo B).
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FIGURE 6. Laryngeal vocal fold papillomatosis, ventricle, and right ventricular band (arrows Photo A). The lesion here is safely acknowledged as a papilloma lesion using chromoendoscopy. It presents a well-defined arborescent area with villi of different shapes and sizes, and it has a warty appearance (see arrows in Photo B).
The average time to complete a careful inspection per patient took roughly 3-5 minutes, according to the length and complexity of the affected areas. At the end of surgery, about the same time was employed again to double check that no residual lesions remained. All the images, obtained during surgery, from different regions such as the supraglottic, glottic, and subglottic were recorded using a digital video recorder. Diagnostic accuracy for respiratory papillomatosis was confirmed on the basis of histological studies. Moderate dysplasia was observed in two patients. Keratosis was found in two patients and there was glottic carcinoma in one patient. In general, under chromoscopy, all papillary lesions were sharply recognized because they had well-demarcated areas. Multiple warty-looking, arborescent, vegetative, or in clusters lesions were scattered over a wide area of the larynx. Other papillomas were observed as flat superficial, localized, erythematous, or small lesions, which were in many cases and many times difficult to recognize using regular microlaryngoscopy (Figures 1, 2, 4–6; Table 2). As we were able to observe in detail the superficial architecture of the papillomatous (villous) surface depicting different contours and sizes we derived, therefore, a papillary pattern TABLE 2. Preoperative and postoperative diagnosis Patients PK RMJ BR NS GF GM CF PC PR FE SJ
Preoperative Diagnosis P P P P P P P P P Papillomatosis vs carcinoma P
Sex Age (y) F M M F M F M M M
15 30 39 53 43 16 33 27 2 65
M
32
Abbreviations: P, papillomatosis; M, male, F, female.
Postoperative Diagnosis P. Mild Atypia P P. Keratosis P. Mild Atypia P P P. Keratosis P P Epidermoid carcinoma P
according to their vascular connective axis which is notable for its morphology: some lacunar (Figure 2, photo A and Figure 1, photo D), starry (Figure 2, photo B) or fusiform (Figure 2, photo C) or combination of spindle-shaped and winding patterns (Figure 2, photo D). Comparing chromo-endoscopic vision with that one obtained using a surgical microscope, in the latter method too many lesions smaller than 2 mm could not be spotted due to their small width. On the contrary, larger lesions could be recognized by both methods. Chromoendoscopy was however more suitable to recognize superficial lesions, and it showed very clearly and with great sharpness all the vegetant lesions and their edges (Figures 3 and 4). In one patient, we identified by indigo carmine two lesions of different morphology. A fully widespread flat lesion at the level of the right supraglottis with well-differentiated boundaries from the rest of the healthy larynx and similarly we properly delimited the boundary of a vegetant papilloma at the level of the glottis and right ventricular band. This condition allowed us making a safe resection of it and therefore preserving the healthy mucosa. The residual dye observed on the supraglottic area belongs to the filling of the cavities lying between the mucosal folds (Figures 5 and 6). At a 24-hour postoperative checkup, a slight edema and scar tissue on RF treated areas were observed in all the patients. In five, the anterior glottis was topically treated with 0.4 mg/mL of Mitomycin C for 5 minutes at the end of the surgical procedure to avoid synechia formation.11 On the sixth postoperative day, granulation tissue formation involving the anterior commissure was observed in one adult patient with a previous history of multiple surgeries for recurrent glottic papillomas. Such a formation was mechanically removed with hyssop under local anesthesia and indirect laryngoscopy in the outpatient therapeutic care room. No adverse reactions were observed with the dye or with Mitomycin C. All patients improved their voice quality after the surgical procedure. Late on the course of this study, we included a last patient who had a preoperative differential diagnosis of glottic carcinoma versus laryngeal papillomatosis. We could exactly define the border of the lesion and differentiate it from a papilloma by analyzing the superficial
6 TABLE 3. Papillary Pattern Classification Fusiform pattern
Winding pattern
Starry pattern
Lacunar pattern
Unstructured pattern (neoplastic)
architecture of the tumor during surgery. Anecdotal observation: the authors observed disorganization of the surface without grooves, no villi, and loss of the vascular pattern of the papilloma (Table 3). Additionally, leukoplakic areas, prominent capillaries, granularity, and erythroplakia surrounding the lesion were identified, which led us to an in vivo anatomical (not
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histological) presumption of dysplasia or malignancy and a diagnosis of glottic carcinoma was subsequently confirmed by anatomic pathology (Figure 7).12,13 DISCUSSION RRP is a benign laryngeal neoplasm most commonly found in childhood. More than 70 types of human papillomavirus have been described.13 Human papillomavirus serotypes 6 and 11 are generally associated with laryngeal disease and affects both sexes and ages.14 Various treatments have been proposed; however, resection is considered the most effective method.15 The current method for removing laryngeal papillomas is their ablation with tweezers and the use of different kind of lasers in conjunction with the conventional microsurgical technique, performed under GA either by orotracheal intubation or jet ventilation. Although the disease is almost always benign, it is common for patients to require repeat surgery. Although the use of laser in recent years has been integrated into microsurgery with adjuvant, intralesional Cidofovir injections have helped reduce the number of reoperations.16–18 These methods have not been adequate, in some patients, to keep RRP under control. The discovery of small superficial lesions is a clear benefit associated with chromoendoscopy. For instance, incipient wart-like lesions are generally seen as mucosal elevations or erythematous areas under microscopic view. If such a lesion is identified, then the next step is to apply some contrast dye. If a lesion is less than 3 mm and is clearly delineated, and it has a papillary pattern on its surface, we proceed to its removal with RF (Figure 8). We could detect minimal lesions by incorporating chromoendoscopy to the endoscopic surgical procedure for PRR, get better visualization of lesion edges, and preserve healthy mucosa during surgery. This method allows the recognition of suspected malignancies and an in vivo detection of residual lesions at postoperative follow-up appointments. Intraoperative lesions of subjects with RRP, which had been overlooked during initial microscopy, were later detected using chromoendoscopy. In our series, chromoendoscopy helped increase the sensitivity compared with that one of the conventional method. Loss of anatomical landmarks and difficulty in
FIGURE 7. Differential diagnosis of malignancy: left vocal fold carcinoma. Prominent capillaries surrounding the lesion are here seen under low chromo-endoscopic vision (Photo A), granularity, leukoplakic surface, loss of papillary pattern, and a disorganization of the capillary pattern all that which led us to the in vivo anatomical (not histological) presumption of dysplasia or malignancy (Photo B).
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NBI) according to the first published studies would increase the chances of early detection of neoplastic lesions. This technology increases the diagnostic capability of endoscopes equipped with narrow-band filters (red, green, and blue bands) consists of a sequential electronic endoscope system and a source of light, yielding very clear images of the mucosal surfaces. Superficial lesions are identified by the changes in color, tone, and irregularity of the mucosal surface during endoscopic examinations. Their visual effect is similar to that one of chromoendoscopy.20
FIGURE 8. Here, the right ventricular band papillomatous superficial lesion measures about 3 mm. Contrast-chromoendoscopy evidences the edge between the papilloma and the healthy tissue. Under microscope, this lesion is only seen as a slight irregularity of the mucosal surface. This early papilloma could be hardly distinguished from an inflammatory or non-specific lesion by microscopy. fully exposing the anterior commissure might lead to an incomplete lesion resection and its local relapse. We treated papillomas with RF in hard-to-observe complex areas such as ventricles and subglottic region which were discovered with the help of 30 and 45 angled endoscopes. Histologically respiratory papillomas are composed of a vascular connective tissue core covered by stratified squamous epithelium with little or no tendency to invade submucosal tissues.13 Indigo carmine provides excellent visualization of mucosal abnormalities and subepithelial capillaries. We are able to define a papillary pattern on the basis of the vascular connective axis with chromoscopy during surgery. This is an important benefit hardly obtained by the regular illumination of endoscopes or surgical microscopes. In our research work, we identified at least four well-defined papillary patterns: lacunar, starry-sky, winding, and fusiform. In most patients, we observed that papillomatous lesions have two or three of the papillary patterns mentioned. Manuel Penaloza-Plascencia et al, in a study of 47 children demonstrated by analysis of viral DNA, co-infection with two or more types of virus in 74% of patients, and in the remaining 26% only one virus type was found.14 The presence of different papillary patterns on the same lesion would lead to conclude, on the basis of this research work, that each pattern would correspond to a definite type of virus, all that which could be confirmed in further studies in the future (Table 3). The first reports on the use of dyes in otolaryngology date back to the days of the work of Andrea Mario and Oscar Dias in Lisbon, Portugal. They defined specific patterns of epithelial cells using contact endoscopy in chronic laryngitis, keratosis, dysplasia, papillomas, and other malignancies. Contact endoscopy during microlaryngoscopy allows in vivo and in situ examination of previously methylene blue -stained epithelial layers.19 Then again, new endoscopic methods for diagnosis such as images obtained with narrow band light (Narrow-band imaging,
CONCLUSION Chromoendoscopy associated with endoscopic laryngotracheal surgery could increase the sensitivity for detection of small superficial lesions hardly visualized by means of traditional methods, and it could also play an important role in the diagnosis and treatment of respiratory mucosal diseases such as RRP. Tests with different dyes, such as those ones used in gastroenterology, guarantee a promising future of this technique in the early detection of lesions lying in the respiratory mucosa. The institution of chromoendoscopy associated with laryngeal or tracheal endoscopic surgery could significantly change diagnostic and surgical strategies for the treatment of RRP. RRP may possibly be detected at an early stage using this staining method and hence it would allow a curative resection. In short, the use of chromoendoscopy in RRP is useful for detecting lesions observed during preoperative endoscopic examinations, improving lesion border visualization, preserving healthy endolaryngeal mucosa (by differentiating between healthy from diseased tissue), allowing a detailed observation of surfaces lesion (to establishing differential diagnoses, ie, suspicion of a malignant lesion) and assessing the presence of residual injuries in vivo (intraoperative procedure). AWARDS ‘‘Prof. Dr. Juan Carlos Arauz’’ First Prize for ‘‘A new technique for treating recurrent respiratory papillomatosis using chromoendoscopy associated with Endoscopic Laryngotracheal Surgery (ELS)’’ research paper—granted by the Argentine Society of Otolaryngology and Children Phonoaudiology—at the IX Argentinian Congress of Pediatric Otolaryngology and Children Phonoaudiology during the III IAPO** Regional Meeting, Cordoba, May 24, 2007. **International Alliance of Patients’ Organizations. REFERENCES 1. Kleinsasser O. Endolaryngeal microsurgery. In: Techniques and Typical Atlas Images. 2nd ed. Editorial Cientifico-medica; 1978. 2. De Rezende L, Parra-Blanco A. Usefulness of chromoendoscopy as an auxiliary method of colonoscopy. Gastr Latinoam. 2005;16:192–204. 3. Sharma P, Weston AP, Topalovski M, Cherian R, Bhattacharyya A, Samplinier RR. Magnification chromoendoscopy for the detection of intestinal metaplasia and dysplasia in Barrett’s esophagus. Gut. 2003;52:24–27. 4. Sano Y, Saito Y, Fu L-I, Matsuda T, Uraoka T. Efficacy of magnifying chromoendoscopy for the differential diagnosis of colorectal lesions. Dig Endosc. 2005;17:105–116.
8 5. Ribeiro MD. Chromoendoscopy for early diagnosis of gastric cancer. Eur J Gastroenterol Hepatol. 2006;18:831–838. 6. Kiesslich R, Neurath MF. Chromo and magnifying endoscopy for colorectal lesions. Eur J Gastroenterol Hepatol. 2005;17:793–801. 7. Gousse A, Safir M, Madjar S, Ziadlourad F, Raz S. Life-threatening anaphylactoid reaction associated with indigo carmine intravenous injection. Urology. 2000;44:271–272. 8. Kudo S, Hirota S, Nakajima T, et al. Colorectal tumors and pitt pattern. J Clin Pathol. 1994;47:880. 9. Marin R, Gil MV, Castilian MM, Alvarez C, Belda O. Review of the clinical application of the dye in chromoendoscopy digestive and compounding. Farm Hosp. 2006;30:112–119. 10. Rey Caro EP, Rey Caro DG, Rey Caro EA. Laryngeal endoscopic surgery (VATS laryngeal microsurgery by telescopes) method for visualization of lesions with difficult access. Revista de la Sociedad Argentina de Otorrinolaringologıa. 2006;2:69–73. 11. Roh J-L, Yoon Y-H. Prevention of anterior glottic stenosis after transoralmicroresection of glottic lesions previous involving commissure with mitomycin C. Laryngoscope. 2005;115:1055–1059. 12. Jako GJ, Kleinsasser O. Endolaryngeal micro-diagnosis and microsurgery. Reprinted from de Annual Meeting of the American Medical Association; 1966.
Journal of Voice, Vol. -, No. -, 2014 13. Benjamin B. Multiple respiratory papillomas. London, UK: Endolaryngeal Surgery; 1998. 14. Penaloza-Placencia M, Montoya-Fuentes H, Flores-Martinez SE, Fierro Velasco FJ, Penaloza-Gonzalez JM, Sanchez-Corona J. Molecular identification of 7 human papillomavirus types in recurrent respiratory papillomatosis. Arch Otolaryngol Head Neck Surg. 2000;126:1119–1123. 15. Zeitels SM, Sataloff RT. Phonomicrosurgical resection of glottal papillomatosis. J Voice. 1999;13:123–127. 16. Mandell DL, Arjamand EM, Kay DJ, Casselbrant ML, Rosen CA. Intralesional cidofovir for pediatric recurrent papillomatosis. Arch Otolaryngol Head Neck Surg. 2004;130:1319–1323. 17. Pransky SM, Brewster DF, Magit AE, Kearns DB. Clinical update on 10 children treated with intralesional cidofovir injection for severe recurrent respiratory papillomatosis. Arch Otolaryngol Head Neck Surg. 2000;126:1239–1243. 18. Seth M, Magit AE, Kearns DB, Kang DR, Duncan NO. Intralesional cidofovir for recurrent respiratory papillomatosis in children. Arch Otolaryngol Head Neck Surg. 1999;125:1143–1148. 19. Andrea MD, Dias O, Santos. Contact endoscopy of the vocal cord: normal and pathological patterns. Acta Otolaryngol. 1995;115:314–316. 20. Watanabe A, Tsujie H, Taniguchi M, Hosakawa M, Fijita M, Sasaki S. Laryngoscopic detection of pharyngeal carcinoma in situ with narrowband imaging. Laryngoscope. 2006;116:650–654.