Cricotracheal resection for pediatric subglottic stenosis

Until recently, cricotracheal resection (CTR) has not been commonly accepted as a treatment modality for severe subglottic stenosis in the pediatric age group. The reasons have included the risk of a possible dehiscence at the site of the anastomosis, the likelihood of injury to the recurrent laryngeal nerves, and the interference with normal growth of the larynx. Thirty-eight infants and children with a severe subglottic stenosis underwent a partial cricoid resection with primary thyrotracheal anastomosis. Thirty-three patients were tracheotomy-dependent at the time of surgery and 34 were referred cases; 27 were classified as grade III, and 10 as grade IV stenoses according to new Cotton's classification. Nineteen patients were younger than 3 years of age at the time of surgery. The tracheotomy was resected during the surgical procedure in 21 cases. Decannulation was achieved in 36/38 cases after an open procedure. There is one complete restenosis and one good result awaiting decannulation after further surgery for a Pierre Robin syndrome. The authors experienced no lesion of the recurrent laryngeal nerves and no fatality. Thirty-one patients show no exertional dyspnea, three a slight stridor while exercising, and two patients are not decannulated. The postoperative follow-up in longer than 10 years in eight cases. All patients show a normal growth of the larynx and trachea. Compared to laryngotracheoplasties, CTR gives better results for severe subglottic stenosis. This operation should become the treatment of choice for severe (grade III and IV) subglottic stenosis in infants and children.

A photosensitising adenovirus for photodynamic therapy

We have developed a new approach to photodynamic therapy based on adenoviral transduction of the rate-limiting enzyme in heme synthesis. Conventional phototherapy uses porphyrin-based chemical photosensitisers, including delta-aminolaevulinic acid (ALA) which is converted to protoporphyrin IX (PpIX) by the enzymes of the heme biosynthetic pathway. The lack of a specific mechanism for targeting chemical photosensitisers and PpIX to tumour cells means that therapeutic irradiation can damage normal tissue and exposure to sunlight following treatment can cause severe burns. The rate limiting enzyme in PpIX synthesis is ALA-synthase (ALA-S). We have developed a new yeast vector system for manipulation of the adeno- virus genome and used it to construct a virus expressing a mutant form of ALA-S lacking the iron response elements which regulate ALA-S translation and the heme regulatory motifs which regulate import of ALA-S into mitochondria. The virus induces a large increase in PpIX expression and confers photosensitivity on cultured cells. Unlike conventional photodynamic therapy, a viral approach makes it possible to restrict photosensitivity by biological rather than purely physical or chemical means. As with HSV thymidine kinase, ALA-S expression is a general mechanism for sensitisation to a therapeutic agent which can easily be adapted to whatever means of gene delivery is most effective.

Abrasive esophageal cytology for the oncological follow-up of patients with head and neck cancer

OBJECTIVES

The occurrence of a second primary cancer in the esophagus in patients with head and neck squamous cell carcinoma is frequent and is associated with a poor prognosis. The aim of this study was to evaluate the yield of abrasive esophageal cytology as a means of screening for metachronous cancer of the upper aerodigestive tract.

STUDY DESIGN

We retrospectively reviewed the results of abrasive esophageal cytology performed twice yearly for the screening of patients with prior head and neck cancer.

METHODS

From 1987 to 1996, 320 patients treated for head and neck cancer underwent 1,673 abrasive cytology examinations of the esophagus during a mean follow-up period of 4 years. Cytological results were classified as negative, suspect, or positive for malignancy.

RESULTS

Twenty-five patients without symptoms had one or more suspect or positive cytologic findings, leading to 29 endoscopic examinations. These revealed 20 premalignant or early malignant lesions of the esophagus (2 dysplasias, 18 squamous cell carcinomas), 2 glandular carcinomas, and 10 clinically unsuspected oral or pharyngeal carcinomas. In seven patients, positive cytological results were associated with clinically visible head and neck cancer. Of the 34 patients with suspect cytological results for malignancy, 10 had no evidence of tumor at endoscopy and 24 had no endoscopic examination because of refusal or because suspected cells were not found in additional examinations. Negative results on cytological examination were found for 254 patients throughout their follow-up, and none of them developed esophageal cancer during a mean follow-up period of 3 years.

CONCLUSIONS

For patients with head and neck cancer, abrasive sponge cytology is useful for detecting esophageal cancer at an early stage. In addition, it may reveal unsuspected second primaries or recurrences in the head and neck region.

Long-segment congenital tracheal stenosis: treatment by slide-tracheoplasty

BACKGROUND/PURPOSE

The prognosis of long-segment funnel-shaped congenital tracheal stenosis improved with surgical management by enlargement-tracheoplasty with a pericardial patch. However, the final outcome is not always satisfying mainly because of the complications related to the pericardial graft and because of misdiagnosed associated cardiovascular malformations. The objective of the report is to show a further improvement of the prognosis by a thorough preoperative planning and the use of a slide-tracheoplasty for the cure of the stenosis, to avoid the major drawbacks of enlargement tracheoplasties.

METHODS

Two children, 7 months and 3 years old, underwent a bronchoesophagoscopy, spiral computed tomography, an echocardiogram, and a heart catheterization. The tracheal stenosis and the associated severe cardiovascular malformations were cured during a single operative session under cardiopulmonary bypass; the tracheal stenosis was corrected by a slide-tracheoplasty.

RESULTS

The postoperative period was remarkably uneventful and the recovery extremely quick (hospital stay of 18 and 17 days). The midterm results are excellent, and the tracheal growth is not impaired (follow-up of 3 1/2 and 3 years).

CONCLUSIONS

According to the authors' experience and to the literature, the slide-tracheoplasty seems to be the most efficient surgical procedure for correction of long-segment funnel-shaped congenital tracheal stenosis. But the success of the treatment depends also on a complete preoperative diagnosis allowing a 1-stage surgical treatment of all associated thoracic malformations.

Outpatient ENT surgery in an academic center: one and a half year's experience

OBJECTIVE/PROBLEM: Evaluation of the early phase of an ENT outpatient surgery programme.

STUDY DESIGN

Between May 1995 and December 1996, 452 ENT outpatient operations were carried out on 416 patients. In order to determine the patients' satisfaction as well as the types and frequency of complications associated with ambulatory procedures, an 18 item multiple choice questionnaire was sent to all patients.

RESULTS

Replies were received from almost 80% of the patients. The great majority of patients were satisfied with their operation and would recommend it to friends and relatives. Ten percent of the patients had to be hospitalised for longer than originally expected. The reasons for these prolonged stays are described.

CONCLUSIONS

Our results show that procedures performed on an outpatient basis do not differ from similar in patient procedures with regard to the types and frequency of complications. Medical expenses are reduced from 200-400% depending on the type of operation. In the present climate of tighter economic controls, the feasibility of lowering medical costs substantially without compromising patient care deserves our utmost attention.

Stability of the fluorescence measurement of Foscan in the normal human oral cavity as an indicator of its content in early cancers of the esophagus and the bronchi

Photodynamic therapy (PDT) with Foscan (mTHPC) is used to cure early cancers of the esophagus or the tracheobronchial tree. However, fixed PDT parameters (drug dose, light dose, etc.) do not permit an accurate prediction of the tissue damage. Large interpatient fluctuations in tissue drug level, at the time of light application, suggest that the light dose must be adjusted to the drug dose shortly before the PDT. This drug dose can be measured endoscopically by light-induced fluorescence spectroscopy, but this measurement is inconvenient and somewhat difficult. A better test site, yielding comparable information, is needed. The oral cavity seems ideal. However, it first had to be established to what extent the estimation of the drug dose was dependent upon the location of the measurement and the pressure applied to the probe. These measurements prove to be not only correlated to similar measurements in the esophagus or the bronchi but also more consistent and less sensitive to the location and the applied pressure. The buccal mucosa is therefore recommended as a test site for measuring the Foscan fluorescence signal at the time of PDT in the esophagus or the bronchi. This measurement is accurate enough for use in light-dose adjustment.

The role of acoustic rhinometry in the pre- and postoperative evaluation of surgery for nasal obstruction

This is a prospective study evaluating the role of acoustic rhinometry (AR) in the measurement of nasal patency before and after surgery for nasal obstruction. We examined 27 patients before and 2 to 6 months after septoplasty associated with turbinoplasty, cauterisation of the inferior turbinates, rhinoplasty or uvulopalatopharyngoplasty in some cases. Surgery was performed for subjective nasal obstruction and indication based on symptoms and clinical findings. AR was performed after indication was made. Patients were evaluated for this study by marking subjective global nasal obstruction on a visual analogue scale and by AR before and after decongestion. All patients noted an improvement of subjective nasal patency after surgery. Mean unilateral minimal cross-sectional area (MCA) of the preoperatively narrower side and total MCA both increased but showed wide ranges with also negative results. The total volume of the nasal fossae did not increase. The volume of the preoperatively narrower nasal fossa increased with surgery, but there are enormous ranges. We could not find any correlation between the MCA of the preoperatively narrower side or the total MCA and subjective nasal patency, neither before nor after surgery. The same was the case for the volume of the nasal fossae. In our opinion AR is not a valuable method for the indication or evaluation of surgery for nasal obstruction.

Partial cricotracheal resection for severe pediatric subglottic stenosis: update of the Lausanne experience

Until recently, severe pediatric subglottic stenosis (SGS) has been treated almost exclusively by laryngotracheoplasty procedures. Even in the most experienced centers, the results of single-stage operations for Cotton's grade III and IV stenoses have been disappointing. This paper reports our experience on 31 partial cricotracheal resections for severe SGS in infants and children. The stenosis was congenital in 6 cases and acquired after prolonged intubation in 25 cases. Twenty-seven patients were tracheotomy-dependent at the time of surgery. Twenty-two cases were classified as grade III and 9 cases as grade IV stenoses according to Cotton. The decannulation rate was 97% (30 of 31 cases) after an open procedure. There were no fatalities and no lesions to the recurrent laryngeal nerves, but there was 1 complete restenosis. Twenty-seven patients show no exertional dyspnea, 3 have a slight stridor with some dyspnea while exercising, and 1 patient is not decannulated. The voice is normal in 21 cases, a dysphonia is present in 9 cases, and the patient with complete restenosis acquired an esophageal voice. Postoperative follow-up is longer than 10 years in 8 cases and longer than 5 years in an additional 6 cases. All patients who reached adulthood show normal growth of the larynx and trachea. Considering the excellent results obtained in this consecutive series of 31 cases, partial cricoid resection with primary thyrotracheal anastomosis should be considered an important treatment option for severe SGS in infants and children.

Clinical evaluation of the cutaneous phototoxicity of 5,10,15,20-tetra(m-hydroxyphenyl)chlorin

The cutaneous phototoxic reaction induced by intravenous injection of 5,-10,-15,-20-tetra(m-hydroxyphenyl)chlorin (mTHPC) has been clinically evaluated in patients undergoing photodynamic therapy. These tests were performed on the backs of 23 patients with a solar simulator at various times after drug administration ranging from 5 h to 57 days. The mTHPC doses ranged from 0.1 to 0.3 mg/kg, and the illuminations lasted from 30 s up to 8 min. These tests have shown that the duration of the skin photosensitization induced after a typical therapeutic dose of mTHPC (0.15 mg/kg) is less important than with Photofrin (2 mg/kg). The level of mTHPC in the skin was also assessed in vivo and at times corresponding to the irradiations using an optical fiber-based spectrofluorometer. This study indicates that the light-induced fluorescence spectroscopy of mTHPC enables prediction of the degree of photosensitivity of the skin.

Interstitial photodynamic therapy with tetra(m-hydroxyphenyl)chlorin: tumor versus striated muscle damage

PURPOSE

The present study was initiated to determine the conditions under which a single photodynamic treatment would induce maximal damage to a tumor with no or at least minimal reversible damage to a normal striated muscle.

METHODS AND MATERIALS

The technique of interstitial light delivery was used after prior 0.5 mg/kg tetra(m-hydroxyphenyl)chlorin administration in a hamster model. After having estimated the threshold light doses required for minimal muscle damage, the same light doses were applied to squamous cell carcinomas to evaluate the efficiency of interstitial photodynamic therapy. Sixteen and 96 h after the injection, irradiation at 650 nm was performed on the thigh muscle of the left hind leg. The applied light doses ranged between 0.3-15 J and were delivered at an intensity of 44 mW per cm of diffuser length.

RESULTS

The threshold of muscle damage was obtained using light doses of 1.5-3 J at two drug-light intervals of 16 and 96 h, respectively. More than 85% of the tumor mass was destroyed when lesions were illuminated using these threshold conditions. In terms of immediate short-term tumor response, this means that for the given irradiation conditions, a relatively low threshold energy of only 1.5 or 3 J, depending on the drug-light interval, is sufficient to induce massive tumor destruction with minimal muscle damage.

CONCLUSION

These results have implications for evaluating interstitial PDT for squamous cell cancers in unfavorable localization in the oral cavity or pharynx, such as at the base of the tongue.

Food groups and risk of oral and pharyngeal cancer

The role of specific food groups and diet variety on the risk of oral and pharyngeal cancer has been considered using data from a case-control study conducted between 1992 and 1997 in the Swiss Canton of Vaud. Cases were 156 patients (126 males, 30 females) aged under 75 (median age 56) years with incident, histologically confirmed cancer of the oral cavity and pharynx, and controls were 284 subjects (246 males, 38 females, median age 57 years), admitted to the same university hospital for a wide spectrum of acute, non-neoplastic conditions unrelated to tobacco and alcohol consumption or to long-term modification of diet. After allowance for education, alcohol, tobacco and total energy intake, significant trends of increasing risk with more frequent intake emerged for eggs (OR = 2.3 for the highest tertile), red meat (OR = 2.1) and pork and processed meat (OR = 3.2). Inverse trends in risk were observed for milk (OR = 0.4 for the highest tertile), fish (OR = 0.5), raw vegetables (OR = 0.3), cooked vegetables (OR = 0.1), citrus fruit (OR = 0.4) and other fruits (OR = 0.2). The addition of a serving per day of fruit or vegetables was associated with an about 50% reduction in oral cancer risk. The most favourable diet for oral cancer risk is therefore given by infrequent consumption of red and processed meat and eggs and, most of all, frequent vegetable and fruit intake. Diet diversity was inversely related to oral and pharyngeal cancer: ORs were 0.35 for the highest tertile of total diversity, 0.24 for vegetable and 0.34 for fruit diversity. In terms of attributable risk, high meat intake accounted for 49% of oral and pharyngeal cancers in this population, low vegetable intake for 65% and low fruit intake for 54%.

Pharmacokinetics of tetra(m-hydroxyphenyl)chlorin in human plasma and individualized light dosimetry in photodynamic therapy

The pharmacokinetics of the photosensitizer 5,10,15,20-tetra(m-hydroxyphenyl)chlorin (mTHPC) was investigated in the plasma of 20 patients by absorption and fluorescence spectroscopy. The temporal behavior was characterized by a rapid decrease in concentration during the first minutes after intravenous injection of 0.15 mg/kg mTHPC. A minimum concentration in the plasma was reached after about 45 min. The drug concentration then increased again, attaining a maximum after about 10 h, after which it decreased again with a halflife of about 30 h. Irradiation tests in the oral cavity at different time intervals after the injection revealed that the tissue reaction was only partially correlated with the mTHPC plasma level. The tissue response was stronger at later drug-light intervals (1-4 days) than during the first hours after injection even though the mTHPC plasma concentration was higher at the shorter times. Relative mTHPC concentrations were also measured in the mucosae of the oral cavity, the esophagus and the bronchi of 27 patients by light-induced fluorescence spectroscopy using an optical fiber-based spectrometer. These measurements were performed prior to photodynamic therapy (PDT), 4 days after injection of the photosensitizer. Highly significant linear correlations were found between the relative mTHPC concentrations in the mucosae of these three organs. Likewise, the plasma levels of mTHPC measured just before PDT were significantly correlated with the mTHPC concentrations in the three types of mucosae mentioned above. These results indicate that mTHPC plasma levels measured just before PDT can be used for PDT light dosimetry.

Long circulating half-life and high tumor selectivity of the photosensitizer meta-tetrahydroxyphenylchlorin conjugated to polyethylene glycol in nude mice grafted with a human colon carcinoma

In a mode of nude mice bearing a human colon carcinoma xenograft, the biodistribution and tumor localization of metatetrahydroxyphenylchlorin (m-THPC) coupled to polyethylene glycol (PEG) were compared with those of the free form of this photosensitizer used in photodynamic therapy (PDT). At different times after i.v. injection of both forms of 125I-labeled photosensitizer, m-THPC-PEG gave on average a 2-fold higher tumor uptake than free m-THPC. In addition, at early times after injection, m-THPC-PEG showed a 2-fold longer blood circulating half-life and a 4-fold lower liver uptake than free m-THPC. The tumor to normal tissue ratios of radioactivity concentrations were always higher for m-THPC-PEG than for free m-THPC at any time point studied from 2 to 96 hr post-injection. Significant coefficients of correlation between direct fluorescence measurements and radioactivity counting were obtained within each organ tested. Fluorescence microscopy studies showed that m-THPC-PEG was preferentially localized near the tumor vessels, whereas m-THPC was more diffusely distributed inside the tumor tissue. To verify whether m-THPC-PEG conjugate remained phototoxic in vivo, PDT experiments were performed 72 hr after injection and showed that m-THPC-PEG was as potent as free m-THPC in the induction of tumor regression provided that the irradiation does for m-THPC-PEG conjugate was adapted to a well-tolerated 2-fold higher level. The overall results demonstrate first the possibility of improving the in vivo tumor localization of a hydrophobic dye used for PDT by coupling it to PEG and second that a photosensitizer conjugated to a macromolecule can remain phototoxic in vivo.

Clinical photodynamic therapy for superficial cancer in the oesophagus and the bronchi: 514 nm compared with 630 nm light irradiation after sensitization with Photofrin II

Photodynamic therapy (PDT) for cancer in the oesophagus and bronchi with red (630 nm) light may occasionally lead to wall perforation and fistula. Therefore, we investigated the clinical use of a less penetrating wavelength (514 nm) for the curative treatment of nine superficial carcinomas in the oesophagus and bronchi after photosensitization with Photofrin II. Tumours without infiltration beyond the submucosa in the oesophagus and beyond the lamina propria in the bronchi were considered as superficial cancers. The outcome and complications were compared with those of 13 superficial cancers treated with PDT and 630 nm light. In addition, we evaluated histologically the extent of the long-term tissue damage and scarring following treatment of six oesophageal cancers with either green or red light. At first endoscopic control, 7-10 days after PDT, tissue necrosis simply matched the illuminated area, without evidence of selective tumour damage. Six of nine tumours treated with 514 nm light had a complete response compared with nine of 13 after 630 nm irradiation. No perforation or fistula occurred in either treatment group. However, severe chest pain and fever with or without pleural effusion, consistent with occult perforation, were observed in three patients after 630 nm illumination in the oesophagus. Histologically, fibrous scarring in the three distinct sites treated with green light was limited to the superficial layers of the oesophagus. After red light treatment, transmural fibrosis with marked thinning of the oesophageal wall was evident in two of the three specimens available for inspection. These results indicate that PDT with 514 nm light has the potential to cure superficial cancer in the oesophagus and bronchi with essentially the same probability of success as red light. In the oesophagus, green light prevents deep tissue damage, thus reducing the risk of perforation.

[Endonasal sequelae after hypophysectomy]

Each year, 15 transvestibular transseptal transsphenoidal hypophysectomies are performed in Lausanne. The aim of the study was to determine the complications rate of our procedure and their influence on the life quality of patients. Questionnaires were sent to 178 patients, operated between 1984 and 1995. 125 questionnaires were returned. Out of those, 73 patients accepted to undergo a control rhinoscopy. The most frequent complains were nasal obstruction and crusting (38% each), whistling while breathing through the nose (12%), and stuffiness of the upper lip or teeth (7%). Endoscopically, we detected an anterior septal perforation in 10 cases (13.7%), 8 (80%) of which were symptomatic and a posterior septal perforation in 6 cases, all of them being asymptomatic. Finally, 36% of the patients had no complains and 19% of them had an improvement of respiration after the operation. Of the whole series of 178 patients, only 5% had complications requiring an ENT follow-up for longer than 6 months after having been operated.

Photodynamic therapy of early squamous cell carcinomas of the esophagus: a review of 31 cases

BACKGROUND AND STUDY AIMS

Patients with cancers of the head and neck have a strong tendency to develop early synchronous and metachronous carcinomas of the esophagus. In many of these patients, whose general condition is poor as a result of alcohol and tobacco abuse, the second primary cancers require minimally invasive treatment. The aims of this study were to evaluate the efficacy of photodynamic therapy for the treatment of early esophageal carcinomas and to compare the results obtained with three different photosensitizers (hematoporphyrin derivative), porfimer sodium (Photofrin II), and meta-(tetrahydroxyphenyl)chlorin (m-THPC).

PATIENTS AND METHODS

Thirty-one early squamous cell carcinomas (Tis or T1a) of the esophagus were treated by photodynamic therapy in 24 patients. Nine tumors were treated with hematoporphyrin derivative, eight with Photofrin II and 14 with m-THPC.

RESULTS

The early cancers were cured in 84% of patients after a mean follow-up period of 2 years. Because the number of cases included in each group was small, the differences in recurrence rates for the different photosensitizers could not be evaluated statistically, but m-THPC was more phototoxic, induced a shorter period of photosensitization of the skin, and had better selectivity than either of the other photosensitizers. There were four major complications: two stenoses and two esophagotracheal fistulas.

CONCLUSIONS

Photodynamic therapy eradicates early squamous cell carcinomas (Tis and T1a) of the esophagus efficiently. Transmural necroses leading to fistulas can be avoided by using a low-penetrating wavelength of laser light (green light at 514.5 m instead of red light at 630 or 652 nm). Stenoses always result from circumferential irradiation of the esophageal wall, and this can be avoided by using a 180 degrees or 240 degrees windowed cylindrical light distributor.

Use of transcription reporters with novel p53 binding sites to target tumour cells expressing endogenous or virally transduced p53 mutants with altered sequence-specificity

p53 triple mutants (120N/121G/277H, 120H/121G/ 277H, 120S/121G/277H and 120H/121G/277Y) have altered sequence specificity in bandshift assays in vitro and transcription assays in vivo. These mutants activate transcription from the site TTT CATG AAA but not from wild type sites. The triple mutants activate more strongly than p53 with a single 277Y mutation. The TTT site matches the wild type p53 consensus at only 4/10 positions and is not recognised by wild type p53. 277Y mutations have been described in human tumours, and Ewing tumour cells expressing this mutant from the endogenous p53 locus selectively activate transcription from transfected luciferase reporters regulated by TTT-mutant p53 binding sites. p53 mutants with altered sequence specificity have potential advantages for cancer gene therapy: if used to activate transcription of conditionally toxic genes they would allow tumour-targeting by p53, which acts as a sensor for the malignant state, but place control over cell killing in the hands of the clinician. Rare tumours expressing such mutants from the endogenous p53 locus could be targeted directly with p53-regulated suicide vectors, but for most tumours both the p53 mutant and the reporter would need to be encoded by the virus.

Anaesthesia for tracheal resection: report of 17 cases

PURPOSE

Laryngo-tracheal stenosis remains a major complication after prolonged intubation or tracheostomy. Surgical resection with end-to-end anastomosis carries the best long term prognosis. For the anaesthetist, however, this procedure represents a most challenging situation.

METHODS

Since 1993, we have used high frequency jet ventilation (HFJV) for tracheal resection. This paper describes the technique and the results of our series including 7 adults and 10 children.

RESULTS

There were no adverse haemodynamic or ventilatory consequences due to HFJV. Oxygenation was well maintained during the HFJV period. Sixteen of the 17 patients had a good outcome. Despite the good result of the resection-anastomosis, one child still suffers from an associated posterior glottic stenosis.

CONCLUSION

Since the introduction of HFJV for surgery of tracheal stenosis in our institution no complication of this ventilatory technique has occurred. It reduces the manipulation of the ventilation system and the period of apnea, thus decreasing the risk of hypoxaemia. The good access to the surgical field contributes to the success of resection-anastomoses in laryngo-tracheal stenosis.

Evaluation of the bone resistance of the sphenoid and ethmoid sinuses

Functional endoscopic sinus surgery can be associated with iatrogenic complications. Some anatomical structures have been identified this clinically as specific danger sites. The aim of this study was to confirm and to compare these clinical data with measurements of the bone resistance of the sphenoid and ethmoid walls and to point out regions that have increased bony fragility. Critical dynamometric evaluation of the resistance to breakage of these bony structures was made on 21 anatomic specimens. This study allowed the authors to localization of surgical complications, to demonstrate that other regions renowned for their fragility can be relatively robust, and to point out that robust sites can be dangerously fragile as a result of individual morphological variations. Results from this study provide a supplement to the guidelines for novice surgeons to use in identifying dangerous areas.

[The current status of broncho-esophagoscopy in otorhinolaryngology]

Most bronchoscopies and esophagoscopies are currently performed with flexible instruments by the respective specialist. Thus the field of bronchoesophagology is in danger of being fragmented; neither the pneumologist nor the gastroenterologist have the complete overview of the upper respiratory and digestive tract. This review shows that number of pathologic conditions in the ENT area and the mediastinum involve the upper respiratory as well as the digestive tract, and thus underscore the need for combined tracheobronchial and esophageal endoscopy. Mastering of rigid and flexible endoscopy is mandatory to be efficient in diagnostic and therapeutic broncho-esophagoscopy. The ENT specialist is in the best position to maintain an overview of this whole field. New developments in broncho-esophagoscopy are presented and discussed in terms of cost effectiveness.

Clinical imaging fluorescence apparatus for the endoscopic photodetection of early cancers by use of Photofrin II

A fluorescence imaging device applied to the detection of early cancer is described. The apparatus is based on the imaging of laser-induced fluorescence of a dye that localizes in a tumor with a higher concentration than in the surrounding normal tissue after iv injection. Tests carried out in the upper aerodigestive tract, the tracheobronchial tree, and the esophagus with Photofrin II (1 mg/kg of body weight) as the fluorescent agent are reported as examples. The fluorescence is induced by violet (410-nm) light from a continuous-wave (cw) krypton-ion laser. The fluorescence contrast between tumor and surrounding tissue is enhanced by real-time image processing. This is done by the simultaneous recording of the fluorescence image in two spectral domains (470-600 and 600-720 nm), after which these two images are digitized and manipulated with a mathematical operator (look-up table) at video frequency. Among the 7 photodetections performed in the tracheobronchial tree, 6 were successful, whereas it was the case for only 5 of the 15 lesions investigated in squamous mucosa (upper aerodigestive tract and esophagus). The sources of false positives and false negatives are evaluated in terms of the fluorescent dye, tissue optical properties, and illumination optics.