Portuguese Version

Year:  2003  Vol. 69   Ed. 5 - (8º)

Artigo Original

Pages: 636 to 642

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Comparison of functional endoscopic swallow study (FESS) vs. videofluoroscopy (VF) in patients with stroke

Author(s): Sandra Doria1,
Mariana A. B. Abreu2,
Roberta Buch3,
Renata Assumpção4,
Marcelo A. C. Nico5,
Claudia A. Ekcley6,
André Duprat7,
Henrique O. Costa8

Keywords: dysphagia, functional endoscopic swallow study, videofluoroscopy

Abstract:
Patients with dysphagia present great morbidity and mortality, especially those with neurological disorders and/or head and neck surgery, thus warranting a detailed evaluation of swallowing. Videofluoroscopy has been considered the gold standard for evaluating swallowing disorders for many years; however, this test presents limitations in some clinical settings exposing patients to radiation and to the risk of contrast aspiration. In recent years, functional swallow studies using flexible endoscopy (FESS) have been proposed as a quick and highly sensitive way to evaluate patients with dysphagia. Aim: Comparative analysis between NFL and VD in relation to some parameters studied by both of them. Study design: Control study. Material and Methods: Twelve patients with sequelae of ischemic brain strokes were studied prospectively from January to May, 2002. All patients were submitted to VF and FESS with final statistical analysis of the results. Results: VF is essential to evaluate the oral phase and micro aspirations, as well as the triggering of the swallow reflex in the pharyngeal phase. FESS may not visualize the triggering of the pharyngeal phase but is capable of testing the motility and sensibility of the larynx and it also allows direct vision of the food in the pharynx and/or larynx. No statistically significant difference was found for any of the parameters studied when comparing FESS and VF (McNemar test). Conclusion: The comparative analysis between the results of NFL and VD in patients with disphagia showed no significant differences between them.

INTRODUCTION

Swallowing disorders are very frequent in neurological patients and in those with diseases and sequelae of the head and neck surgery, being an important cause of morbidity and mortality 1, 2, 3. Motor and sensitive affections of the larynx, especially those of neurological origin, have not bee fully studied yet 3, 4. As a result of aging, there is a gradual reduction of oropharyngeal and laryngeal sensitivity, which can be maximized by other neurological affections 5, 6. Aspiration pneumonia can have different causes, but there is a strong association with dysphagia, which requires the study of the swallowing mechanism as an essential element for the diagnosis and treatment of this and other severe respiratory complications. Thus, the more data we have about laryngeal functions and the other swallowing mechanism organs, the greater the likelihood of understanding the mechanisms involved in aspiration.

The increasing survival rate of patients after a cerebral vascular accident (CVA) has been influenced by the capacity to make early diagnosis of swallowing problems in this population, preventing secondary complications to aspiration pneumonia.

Swallowing phases are interrelated and may be didactically divided into 4 distinct phases 7: Oral preparation phase: it involves the moment of food grabbing, mastication and manipulation of the food bolus and its centralization on the tongue dorsum; Oral phase: it comprises anterior-posterior tongue movement, taking the food bolus to the pharynx. This movement involves the tongue base as the bolus ejector, with contact with the posterior pharyngeal wall; Pharyngeal phase: it starts from the swallowing reflex. In the oropharynx, there are many sensors capable of triggering the pharyngeal phase of swallowing by light contacts or small pressures in the soft palate, uvula, tongue dorsum, pharyngeal surface of the epiglottis, pillars, pyriform sinuses, pharyngeal posterior wall and pharyngoesophageal transition. When sensors are activated, many events are triggered to cause propulsion of the food bolus towards the esophagus and to protect the lower airways. There is closure of the velopharyngeal sphincter to avoid nasal reflux. The larynx is elevated and moved forward, aryepiglottic folds are contracted, vestibular and vocal folds close as a sphincter, the epiglottis goes down by the contraction of the aryepiglottic folds and the weight of the food and the pharynx starts the contraction movements, pushing the food bolus towards the esophagus; Esophageal phase: it starts by the relaxation of the pharyngoesophageal transition, which opens to the esophageal lumen, allowing the passage of the food to the stomach. The opening of the pharyngoesophageal transition occurs as a result of the elevation and lateralization of the larynx, creating a distance from the cricoid cartilage to the vertebral body, and once opened, the peristaltic movements of the esophagus are triggered.
Clinical assessment of swallowing is traditionally the first analysis to be made, in which we can observe structures of the articulators involved in the swallowing process concerning tone, mobility, sensitivity and coordination of movements.

For many years, videofluoroscopy (VD) has been the exam of choice to assess swallowing disorders 8-10. However, it has limitations in some clinical situations, especially when patients are bedridden, in addition to exposing the patients to radiation and the risk of aspirating the contrast. In recent years, the use of flexible fiber optics to dynamically and functionally assess swallowing in patients with dysphagia and other swallowing-related complaints 2, 10, 13-16 has been advocated. It provides many advantages over VD: it can be performed in the outpatient unit or by the bedside, it is less invasive, does not require contrast, does not expose the patients to radiation and allows the assessment not only of motricity but also laryngeal, pharyngeal and soft palate sensitivity17. Conversely, it does not allow functional assessment of the oral preparation and oral phase of swallowing, nor the transition from oral to pharyngeal phase, owing to swallowing blackout, which can be assessed by VD, and is extremely important for the rehabilitation process of swallowing disorders.

Thus, the present study aimed at critically and comparatively analyzing functional nasofibrolaryngoscopy and videofluoroscopy in patients with history of CVA, highlighting the advantages and disadvantages of both tests.

MATERIAL AND METHOD

Between January and May 2002 we assessed 12 patients with history of ischemic cerebral vascular accident (CVA) for 3 months to 6 years (mean of 16.7 months). The age of patients ranged from 45 to 77 years (mean of 58 years). Of the patients, 10 were male and 2 were female subjects. In all patients, we conducted a dynamic study of swallowing using nasofibrolaryngoscopy (NFL) and videofluoroscopy (VD) with comparison of results obtained with both exams. All patients were previously informed about the nature and the diagnostic purpose of the exams to be conducted, as well as their participation in the scientific study. Only after the informed consent term was signed that they were included in the study.
After careful clinical history including symptoms related to swallowing and phonation, we started the exams.

NFL was the first one to be described since it allows the assessment of laryngeal sensitivity, reason why it may contraindicate the conduction of VD.

The device was introduced through the most pervious nasal fossa, whenever possible, and we avoided the use of nasal or oral anesthetic drugs owing to the risks of reducing the local sensitivity and not to affect the data of the exam concerning sensorial affection. When there was nasal mucosa congestion through which the nasofibrolaryngoscope had to be introduced, we used nasal vasoconstrictor, provided that there were no other clinical contraindications for its use. We studied the following events 18:

 Mobility of the soft palate and efficiency of the Passavant's ring - the nasofibroscope was positioned right after the choanae to provide complete visualization of the ring. The patients were instructed to repeat the palatal phonemes and sentences that contained the palatal phonemes PA-GA-CA to assess anterior-posterior and lateral-lateral mobility of the ring region. Next, the patients were instructed to swallow saliva, observing palatal occlusion and the presence of oropharyngeal reflux to the rhinopharynx and nasal fossa.

 Static aspects of the oro and hypopharynx, as well as the pharynx - next, the optic fiber was taken to the rhinopharynx region and bent down, right after the uvula in which it is possible to completely see the base of the tongue, hypopharynx and larynx. At this moment, we observed salivary stasis or food in the vallecula or the pyriform sinus or involuntary movements of pharyngolaryngeal structures.

 Pharyngeal and laryngeal mobility - mobility of the vocal folds was tested by asking the patients to produce vowels sounds, modulation and connected speech. The patient should swallow saliva and we observed whether there was cough and the need to clean the stasis material. We also observed the synchrony between palate and tongue during swallowing.

 Pharyngeal and laryngeal sensitivity - the device was introduced up to touching the posterior wall of the pharynx, tongue base, epiglottis laryngeal aspect, aryepiglottic folds and arytenoid on each side, successively, observing the reaction of nausea or reflux of swallowing on each tested side.

 Dynamic study of swallowing - We tested the swallowing of solid foods - water, paste, gel-lo, solids - savory crackers, and the liquid was stained with blue methylene drops to facilitate the visualization. Oral phase - This exam does not allow the observation of the oral preparation phase, however, we can collect information that is useful concerning the ability to retain the foods. Regardless of the consistency of foods, the patients were instructed to hold the quantity in the mouth during some seconds and only swallow when requested. In this phase, we observed directly the oral phase by the way the patient controlled the food in the mouth and if there was food leak to the vallecula and pyriform sinuses before swallowing (early leak) with or without aspiration. We could also observe the level of elevation and closure of the palate, as well as the coordination of its elevation with pharyngeal constriction, to prepare to the next phase. Pharyngeal Phase - Next, the patients were asked to swallow the oral content. Even though it is not possible to visualize the pharyngeal phase with the device, moments before swallowing we could visualize the laryngeal elevation and lateral constriction of the pharyngeal constrictor lateral muscles, informing us about the coordination of the beginning of the swallowing reflex. During swallowing, we missed direct vision owing to the closure movement of the soft palate and the rhino, oro and hypopharynx muscles, as well as tongue posteriorization. After the second blackout of the pharyngeal phase of swallowing, it was possible to see again the studied region. We could observe whether the swallowing was effective by complete cleaning of the pharynx and larynx or whether there was food debris in the region. When there was food debris, it was important to observe in which side there was stasis and if there was appropriate cleaning after successive swallowing movements (without food), under request or spontaneously. Such data are also essential for therapeutic guidance. It is also possible to observe late leak of oral content that normally occurs when there is inability to form the food bolus in the mouth with remains in the same swallowing that can accidentally leak to the larynx (if there was associated sensitivity deficit), leading to aspiration. This process of observing swallowing should be repeated with liquid, paste and solid foods in order to determine the specific deficiencies and also to support the definition of the best food consistency to avoid aspiration. Evidently, the exam was interrupted if there was confirmation of sensitivity deficit associated with aspiration during the exam. The VD was conducted by the institution of the radiologist physician, who assessed the structures and controlled the exam and by the speech therapist that assessed swallowing functions. The exam allowed the observation of anatomical and physiological alterations that could cause dysphagia such as to identify and assess the rehabilitation strategy. The endoscopy can be performed in two visualizations: lateral view and anterior-posterior view.

Lateral visualization allows important observations, such as oral and pharyngeal transit time, food debris in the oral and pharyngeal cavity, formation and centralization of the bolus, as well as its movements towards the aerodigestive tract. In addition, we can observe premature loss, penetration and/or aspiration of food and the moment in which they occur: before, after or during swallowing.
In anterior-posterior vision, we can observe the mastication movement of the patient, asymmetry as a function of the pharyngeal walls and vocal folds, directing the food bolus through the pharyngeal wall and presence of stasis in vallecula and pyriform sinus.

In our study, all patients were standing up, first in lateral view and later in the anterior-posterior view. In the lateral view, the limits of the image were: anteriorly, the lips, superiorly, the hard palate, posteriorly, the pharyngeal wall, and inferiorly, the bifurcation of the airways and digestive tract (transition between the posterior region of the arytenoids and the entry of the esophagus).
We offered to our patients foods with liquid, paste and solid consistency. The foods were prepared with liquid barium in the proportion of 1:1 and the solid food (cookies) was soaked in barium. In the lateral view, patients had three swallows of each consistency and in the anterior-posterior view, only one swallow. Radiological exposure was maintained at 0.5mAs, in order to reduce the amount of radiation produced to the patients and the examiners.

Graph 1. Number of patients that presented similar or different results when compared NFL and VD concerning the parameters of soft palate mobility, aspiration, early leak of solid, paste and liquid foods.



Graph 2. Number of patients that presented similar or different results when compared NFL and VD concerning the parameters of late leak, food debris in the vallecula and pyriform sinuses.

RESULTS

All analyzed parameters in the nasofibrolaryngoscopy (NFL) and videofluoroscopy (VD) are shown in graphs 1 and 2.

Among the 12 studied patients, only 4 presented current complaint of swallowing, being that 2 for liquids, 1 for solids and liquids, and 1 for all types of foods. The 8 remaining patients presented swallowing disorders after the installation of the CVA with progressive functional improvement, being that in the study period there were no further swallowing complaints.

As to soft palate mobility, only 2 patients (16%) were presented differences between the two exams, being that in one of them the soft palate mobility was appropriate for NFL and reduced for VD and in another patient the opposite happened.

As to aspiration, only 1 patient (8.3%) presented difference between the two exams, showing absent aspiration in NFL and present aspiration in VD.

As to early solid leak, in 5 patients (41.6%) we found differences in results, being that they presented presence of leak in NFL and absence in VD. As to early paste leak, in 2 patients (16%) we observed differences in results, being present leak in NFL and absent leak in VD. Early liquid leak was detected in 4 patients (33%) with different results, one of them had presence of leak in NFL and absence of leak in VD, and the other three had the opposite situation.

As to late solid leak, in 4 patients (33%) we observed difference in results being that there was presence of leak in NFL and absence of leak in VD. As to late paste leak, in 5 patients (41.6%) we found discrepancy of results, detecting presence of leak in NFL and absence of leak in VD. As to late liquid leak, in 4 patients (33%) there was difference of results, showing presence of leak in NFL and absence of leak in VD.

As to stasis of solids in valleculae, in one patient (8.3%) we found discrepancy of results, with present stasis in NFL and absent in VD. As to paste stasis in valleculae, in 4 patients (33%) there were discrepancies of results, with absence of stasis in NFL and presence of stasis in VD. As to stasis of liquid in the valleculae, in 4 patients (33%) we observed differences in results, with absence of stasis in NFL and presence of stasis in VD.

As to stasis of solid in pyriform sinuses, in 5 patients (41.6%) we observed discrepancy between the results, being that in 4 of them (33%) we observed presence of stasis in NFL and absence of stasis in VD and in one single case (8.3%) we observed the opposite. As to stasis of paste in pyriform sinus, in 4 patients (33%) we observed discrepancy of results, being that in 2 of them (16.6%) we observed presence of stasis in NFL and absence of stasis in VD and in the other two cases (16.6%) we observed the opposite situation. As to liquid stasis in pyriform sinus, in 3 patients (25%) we observed discrepancy between the results, being that in one of them (8.3%) we observed presence of stasis in NFL and absence of stasis in VD, and in the other two cases (16.6%) we observed the opposite situation.
As to cough, it was observed that in 5 patients (41.6%) there was discrepancy in results, being that in 3 of them (25%) we observed presence of cough in NFL and absence of cough in VD, and in one of them (8.3%) we observed the opposite and, lastly, in one (8.3%) we observed cough in swallowing of liquid in NFL and cough in swallowing of solid in VD.

Using the statistical test of McNemar, no analyzed parameters presented statistically significant differences (p<0.05) when we compared NFL and VD.

DISCUSSION

Swallowing disorders can bring great mortality and morbidity since they cause malnutrition or aspiration of food leading to aspiration pneumonia. In the United States, it is estimated that there are about 40,000 deaths every year caused by aspiration after CVA 1. Unfortunately, we do not have these statistics about Brazil, but our empirical experience shows that aspiration is the potential cause of important respiratory difficulties. In view of the problems, it is essential that the diagnosis of aspiration episodes in risk patients, that is, neurological patients with dysphagia or dystonia or pediatric patients, be made as early as possible.

VD provides important data about swallowing, especially about the oral preparation, oral, pharyngeal and esophageal phases, being possible to check the affections of peristaltic movements and food reflux, among other things 2, 3. However, this exam is not capable of assessing sensitivity, which is a fundamental factor in the pathogenesis of aspiration pneumonia.

The dynamic study of swallowing using NFL, as previously described, is less invasive than VD and can provide data about laryngopharyngeal sensitivity and motricity, in addition to being simpler to conduct, since it can be performed in the outpatient unit or by the bedside2, 17. However, both exams provide the possibility of coupling the base device to a video monitor allowing the examiner the review of exams, whenever necessary, and the possibility of analyzing in slow motion, to detect small difficulties and to be used as a feedback to the patient and examiner, specially in periods of pre and post-rehabilitation, which can be compared. The exams are well tolerated by the patients, causing a minimum of discomfort that does not prevent swallowing, which can be made in patients of all ages with minimum collaboration.

There are many studies comparing VD and NFL for the study of swallowing and it is agreed that both exams are capable of determining aspiration and its causes with practically the same sensitivity, but VD assesses better the oral preparation and oral phases and NFL assesses laryngeal and pharyngeal sensitivity 3, 9, 11, 14, 16, 17. It is currently considered that these two exams complete each other, but the latter can be performed by the bedside and it allows an early diagnosis of swallowing disorders, which is essential for the prognosis of patients. It is also essential to perform NFL before VD, especially in cases in which the patients do not control and/or swallow their own secretions, without presenting cough or choking episodes, or when secretions are deliberately eliminated by the tracheostome. In such cases, the affection of laryngeal and pharyngeal sensitivity is evident and the risks of aspiration of foods are greater, demonstrating that it is still not the right time to submit them to the test with foods.

Even though it is not possible to completely assess the oral preparation phase with this technique, we can observe tone and synchrony of the oris orbicular area and the passive and active movements of the tongue before introducing the endoscope through the nasal fossa. These data will be added to others to complete the assessment of swallowing.

Similarly to the literature, using the statistical test of McNemar, no analyzed parameter presented statistically significant difference (p<0.05) upon comparing the data by NFL and VD.

Only in 2 patients there was aspiration, detected by one of the tests being that in one of them there was aspiration detected in both exams and in another one only with VD. In both, aspiration occurred right after the beginning of the pharyngeal phase. Despite the manifestation of aspiration, one of the patients did not present cough and had absent sensitivity only in the epiglottis, aryepiglottic ligament and left arytenoids. Similarly, even though the other patient had aspiration in both tests, he had cough only with liquid showed by NFL and absent sensitivity in the aryepiglottic ligament and left arytenoid. We observed that in the patients that aspirated, sensitivity was abnormal, but the reciprocal was not observed in the other patients: 3 of them (33%) had affected laryngeal sensitivity and of these 3, only one patient presented cough detected in NFL for solid and paste foods. To explain the occurrence of the 3 patients with laryngeal sensitivity affection without aspiration, we believe that the patients could have acquired a defense mechanism, such as cough, and subsequent swallowing, very similar to the supraglottic maneuver. Moreover, the lack of sensitivity can be compensated by an effective pharyngeal phase.

As previously reported, in relation to early leak, there was difference between the results of NFL and VD in 41.6% (solids) and 16% (paste), in which we observed the presence of leak in NFL and absence of leak in VD, being that this was not a statistically significant difference. We should also bear in mind that during NFL, the device was positioned in the lingual aspect of the epiglottis, which certainly leads to discomfort, which can lead to non-physiological swallowing. Another possibility to justify the findings would be questioning of where in fact the swallowing reflex is triggered, that is, what we name leak is in fact a swallowing reflex triggered at a different site from the one described in the literature - posterior tonsillary pillar? 7, 9 This fact has already been discussed in the international literature. It is known that there are many sensors in the oropharynx that, in greater or lesser degree of sensitivity, are capable of triggering the beginning of the pharyngeal phase, differently from what used to be described before. To the subjects that have no abnormalities of the swallowing process of mechanical or neurological origin, to have the beginning of the pharyngeal phase at the vallecula, posterior pharyngeal wall, pyriform sinuses or even the pharyngoesophageal transition may not pose risks to the lower airway tract. However, for a subject that has affection, the risk is constant and during the rehabilitation process, the speech therapist has to maximize the oral preparation and the oral phase, increasing the sensitivity of the oral cavity and the oropharynx region trying to adapt the reflex of swallowing to the oropharynx 20.

We could observe the different sites in which the swallowing reflex was triggered in the 12 studied patients. Only in 2 patients the swallowing reflex was triggered in the tonsillary pillars.

In relation of early liquid leak, we observed in 25% of the patients a discrepancy opposite to what was observed with paste and solid. Probably, it was resultant from the difficulty in NFL in visualizing aspiration or liquid penetration. It is known exactly what is the explanation for such occurrence, but we can imagine that it is that the liquid is lighter and less viscous and it has a quick passage during swallowing and does not adhere to the walls as it happens with other consistencies.

As to stasis of solids in the valleculae, there were different results in only one patient (8.3%), but considering stasis of paste and liquids, 33% of the patients presented absence of stasis in NFL and presence pf stasis in VD. Despite the fact that it was not a statistically significant difference, VD normally allows better visualization of the food stasis in the valleculae owing to the contrast under endoscopic analysis.

As to solid stasis in the pyriform sinuses, in 33% of the patients we detected stasis in NFL not confirmed by VD. Probably it was owing to the fact that in lateral view of VD there is not as a good visualization as in anterior-posterior vision, which in this study, was conducted only one time.
Through the results collected, we could observe that NFL and VD complement each other in the general assessment of the patients that have dysphagia. The functional assessment of swallowing with NFL allows evaluation of aspects related to laryngeal sensitivity, functioning of velopharyngeal sphincter during speech and the presence of local food stasis in the pyriform recess, which is not possible in the lateral view of VD. It is important to point out that mobility of velopharyngeal sphincter during speech is also assessed by VD.

VD allows us to assess the aspects related to the oral phase of swallowing, such as preparation of the food bolus and its centralization, and oral cavity stasis, which is not possible by nasofibrolaryngoscopy. Moreover, it is possible to observe the oral phase transition, to the pharyngeal phase of swallowing, which does not occur in the NFL as a result of the blackout, described in the material and method section.

Thus, some parameters are only analyzed by the NFL exam, whereas others are analyzed only by VD, but most of them can be comparatively analyzed by both. Salivary stasis in rhinopharynx, saliva reflux to the rhinopharynx, salivary stasis in the valleculae, pyriform sinuses and retrocricoid region, tremors and involuntary movements of the pharyngolaryngeal region, mobility of the vocal folds, sensitivity of the pharyngolaryngeal region are parameters that can only be assessed by NFL. Conversely, the analysis of effectiveness of the oral preparation phase and the pharyngeal phase of swallowing cannot be analyzed by NFL but rather by VD.

As seen before, most of the parameters were similar in both exams in the studied patients, making it clear that VD allows the analysis of the oral preparation and oral phase of swallowing and the beginning of the pharyngeal phase, and NFL, conversely, allows the detailed study of laryngopharyngeal sensitivity and mobility.

We know that the earlier the introduction of oral intake in patients with neurological sequelae, the better will be quality of life and prognosis. However, it should be safely made. As seen in this pilot study, NFL and VD allow the determination of aspiration and provide important data to allow rehabilitation of swallowing in an appropriate and effective fashion.

CONCLUSION

Comparative analysis between the data obtained by NFL and VD concerning the parameters assessed by both methods in patients with dysphagia showed there were no statistically significant differences between them. Therefore, the exams are complementary, each one has advantages and disadvantages and together they provide complete assessment of swallowing.

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1 Resident Physician, Department of Otorhinolaryngology, Santa Casa de Sao Paulo.
2 Resident Physician, Department of Otorhinolaryngology, Santa Casa de Sao Paulo.
3 Speech Therapist, Santa Casa de Sao Paulo.
4 Advanced Studied in Neurogenic Dysphagia under course, Division of Speech and Hearing Pathology, Santa Casa de Sao Paulo.
5 Resident Physician, Department of Imaging Diagnosis, Santa Casa de Sao Paulo.
6 Assistant Professor, Department of Otorhinolaryngology, Santa Casa de Sao Paulo.
7 Professor, Department of Otorhinolaryngology, Santa Casa de Sao Paulo.
8 Joint Professor, Department of Otorhinolaryngology, Santa Casa de Sao Paulo.
Study conducted at the Departments of Otorhinolaryngology and Imaging Diagnosis, Santa Casa de Sao Paulo,
approved by the Research Ethics Committee, Santa Casa de Sao Paulo.
Address correspondence to: Sandra Doria - Rua Caativa, 358 Alto da Lapa - Sao Paulo 05059040.
Study presented at 36º Congresso Brasileiro de Otorrinolaringologia, held on November 19 - 23, 2002 in Florianópolis (free communication paper).
Article submitted on April 29, 2003. Article accepted on August 08, 2003.

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