Effectiveness of fibrin coating in the management of web formation after laryngomicrosurgery.

PURPOSE: To explore the effectiveness of fibrin coating in reducing web formation after endoscopic management of the anterior commissure of the larynx. MATERIALS AND METHODS: Using a spray device that is generally used for laparoscopic operations, we covered the wound with fibrin glue (Bolheal®) to avoid web formation. This technique was employed in cases wherein the anterior commissure was mainly managed by laser operation; the glue was sprayed after vaporization. Fibrinogen was first sprayed and the wound was properly soaked with a swab, which was followed by application of thrombin. We used this method in 17 cases and evaluated voice function by acoustic analysis - pitch perturbation quotient (PPQ) and amplitude perturbation quotient (APQ) - and maximum phonation time (MPT) before and after the operation. RESULTS: No severe web formation was observed at three months after the operation. PPQ values improved from 3.048±2.801% to 0.653±0.463% (p<0.05, paired t-test). APQ values improved from 7.996±5.003% to 3.042±1.872% (p<0.05, paired t-test). Voice quality did not worsen in any of the cases. MPT values improved from 17.2±10.8s to 26.7±14.2s (p<0.05, paired t-test) Voice function improved 3months after the operation in all cases. CONCLUSION: The fibrin coating method is an easy and effective approach to avoid web formation without creating cervical wounds in cases that require handling of the anterior commissure under laryngomicrosurgery.

Thinning and thickening transitions of foam film induced by 2D liquid-solid phase transitions in surfactant-alkane mixed adsorbed films.

Mixed adsorbed film of cationic surfactant and linear alkane at the air-water interface shows two-dimensional phase transition from surface liquid to surface frozen states upon cooling. This surface phase transition is accompanying with the compression of electrical double layer due to the enhancement of counterion adsorption onto the adsorbed surfactant cation and therefore induces the thinning of the foam film at fixed disjoining pressures. However, by increasing the disjoining pressure, surfactant ions desorb from the surface to reduce the electric repulsion between the adsorbed films on the both sides of the foam film. As a result, the foam film stabilized by the surfactant-alkane mixed adsorbed films showed unique thickening transition on the disjoining pressure isotherm due to the back reaction to the surface liquid films. In this review, we will summarize all these features based on the previously published papers and newly obtained results.

Sarcoidosis of the tongue: a case report.

A case of sarcoidosis involving the tongue is described in a 48-year-old Japanese man. A definite diagnosis of sarcoidosis was made for the clinical lesion and pathological examinations. Sarcoidosis is a multisystem granulomatous disease that may affect any organ. Sarcoidosis of the tongue is particularly rare.

Endonasal endoscopic surgery with combined middle and inferior meatal antrostomies for fungal maxillary sinusitis.

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of the combination of inferior and middle meatal antrostomies for treatment of a maxillary sinus fungus ball by functional endoscopic sinus surgery. METHODS: A retrospective analysis including 28 patients with non-invasive fungal maxillary sinusitis was performed. Fourteen patients underwent FESS with both middle and inferior meatal antrostomies (combined group). The remaining 14 patients were treated with FESS through only the middle meatal antrostomy (control group). RESULTS: Post-operative computed tomography showed normal maxillary sinuses in all patients in the combined group. In contrast, in the control group, five patients (36 per cent) exhibited a normal maxillary sinus, seven (50 per cent) showed maxillary mucosal thickening and two (14 per cent) had persistent fungus balls in the maxillary sinus. CONCLUSION: FESS with a combination of middle and inferior meatal antrostomies proved more effective for treating fungal maxillary sinusitis.

New technique for laryngomicrosurgery: narrow band imaging-assisted video-laryngomicrosurgery for laryngeal papillomatosis.

OBJECTIVE: In the present report, we describe the use of narrow band imaging during video-laryngomicrosurgery for laryngeal papillomatosis. CASE REPORT: It is difficult to peri-operatively locate all the superficial papillomatous lesions when the disease is widespread, which then results in tumor recurrence. Therefore, we have constructed a narrow band imaging video-laryngomicrosurgery system, which we have used for two cases of laryngeal papillomatosis. CONCLUSION: Our narrow band imaging-assisted video-laryngomicrosurgery system to visualise superficial laryngeal papillomatosis more clearly.

Clinical outcomes of tracheoesophageal diversion for intractable aspiration.

OBJECTIVES: The purpose of the present study was to examine the clinical outcomes of using tracheoesophageal diversion for preventing intractable aspiration. METHOD: We retrospectively reviewed 25 patients who underwent tracheoesophageal diversion from 2003 to 2009 at our hospital (median age, 25 years; range, 0-78 years). End-to-side anastomosis was used in 16 cases and side-to-side anastomosis was used in 9. RESULTS: The average operative time was 141 minutes for end-to-side anastomosis and 191 minutes for side-to-side anastomosis. Peri-operative complications were observed in only two (8 per cent) cases: one with infection and one with haematoma. No fistulas were observed. Aspiration was prevented in all cases, but the nutritional route depended on the swallowing function of the patient. Oral feeding was the main nutritional route after surgery in only four patients (16 per cent). CONCLUSION: This procedure is well suited to patients who lack speech communication and are at high risk of aspiration.

Medullary swallowing-related neurons in the anesthetized cat.

Swallowing-related neurons (SRNs) were recorded systematically in the medulla oblongata of urethane-anesthetized cats. The SRNs received orthodromic inputs from the superior laryngeal nerve (SLN) and showed transient changes in their activity synchronous with swallowing. These neurons could be divided into three types. Type I SRNs are sensory-relay neurons from the SLN in the nucleus of the tractus solitarius (NTS), type II are interneurons located diffusely in the parvocellular reticular formation ventral to the NTS, which received oligosynaptic inputs from the SLN, and type III are motoneurons in the nucleus ambiguus. Some type II neurons still showed the swallowing activity after the animals were paralysed, which suggests that they could be involved in the generation of swallowing outputs.

Vestibular inputs to bulbar respiratory interneurons in the cat.

Vestibular inputs to medullary respiratory interneurons were studied in decerebrated and artificially ventilated cats. Extracellular recordings were made from 40 neurons located in the area of pre-Bötzinger complex and activated antidromically from the contralateral ventral respiratory group. Neuronal populations analyzed included inspiratory and expiratory neurons with augmenting, constant and decrementing firing patterns, and a late inspiratory neuron. Seventeen neurons responded to ipsilateral and/or contralateral vestibular nerve electrical stimulation. These responses were observed in all seven cell types. Most neuronal reflex responses consisted of inhibition, while a few consisted of either excitation or a combination of both inhibition and excitation. These results indicate that pre-Bötzinger respiratory interneurons, which may be involved in respiratory rhythmogenesis, also participate in vestibulorespiratory responses.

Fictive vocalization in the cat.

A new animal model is described for the study of fictive vocalization, evoked by electrical stimulation of the periaqueductal grey (PAG) in decerebrate, paralyzed and artificially ventilated cats. Changes in activities of the phrenic, abdominal, recurrent and superior laryngeal nerves induced by PAG stimulation after induction of paralysis were compared with the activities of these nerves or the muscles innervated by them during actual vocalization induced before paralysis. The PAG-induced respiratory and laryngeal motor pattern in paralyzed cats is similar to that of PAG-induced vocalization. Furthermore, the switch from inspiration to vocal-like activity is usually synchronized with lung inflation in both paradigms. It is concluded that fictive vocalization can be induced by PAG stimulation in paralyzed cats.

Crossing inputs of the superior laryngeal nerve afferents to medullary swallowing-related neurons in the cat.

To understand the neural mechanism for generation of synchronous activity on both sides during swallowing, we examined the convergence of inputs from the bilateral superior laryngeal nerves (SLNs) in the urethane-anesthetized cat medulla and we also examined the changes in swallowing outputs after a longitudinal brain-stem split in decerebrate cats. Twenty-six (31%) of 84 swallowing-related neurons (SRNs) that were oligosynaptically activated by ipsilateral SLN stimulation and recorded mostly in the reticular formation received contralateral inputs, which were confirmed by orthodromic spike responses (n = 16) or were detected as subliminal facilitatory or inhibitory inputs (n = 10) using conditioning-test stimuli. The rate of convergence of inputs from bilateral SLNs in these SRNs was significantly higher than that (4%) in the SRNs that were regarded as sensory-relay neurons in the nucleus tractus solitarius (NTS). The SRNs receiving signals from the contralateral SLN were located diffusely from the NTS and the adjacent reticular formation to the nucleus ambiguus (NA) and the reticular formation dorso-medial to the NA. A midsagittal split from 3 mm caudal to 6 mm rostral to the obex could change symmetrical swallowing to unilateral swallowing. Thus the crossing projections to the contralateral SRNs appear to contribute to symmetrical swallowing.

Recovery of retching after lesions involving the nucleus of the solitary tract.

The nucleus of the solitary tract (NTS) in the caudal brainstem receives various inputs that trigger vomiting. Chemical (kainic acid) NTS lesions in decerebrate, paralyzed cats temporarily suppressed fictive vomiting induced by different emetics. Subsequently, retching but not expulsion, resumed in 2-3.5 h. Since the NTS does not appear essential for retching, antiemetic drugs targeted at the NTS may not completely suppress vomiting.

Role of nucleus retroambigualis in respiratory reflexes evoked by superior laryngeal and vestibular nerve afferents and in emesis.

An ascending projection from the medullary nucleus retroambigualis (NRA) has recently been described as important for the control of the upper airway during vocalization. We evaluated the importance of this projection in other behaviors by making localized injections of the neurotoxin kainic acid in the NRA in decerebrate cats, most of which were paralyzed and artificially ventilated. In contrast to its importance for vocalization, the NRA is not essential for activation of upper airway musculature during respiration, swallowing, vomiting, or reflexes elicited by superior laryngeal or vestibular nerve afferents. However, kainic acid injections in the NRA and adjacent reticular formation prolonged the inhibitory phrenic motoneuronal response to superior laryngeal nerve stimulation and abolished or reduced abdominal motoneuronal responses during respiration, vomiting, and superior laryngeal nerve stimulation. Thus, of the behaviors we investigated, the importance of the ascending projection from the NRA appears to be limited to vocalization, while descending projections from the NRA region are important in a number of behaviors.

Upper airway motor outputs during vomiting versus swallowing in the decerebrate cat.

Swallowing and vomiting are antagonistic motor acts; nevertheless, vomiting can be immediately followed by swallowing. The purpose of this study was to clarify the interrelationship between these two behaviors, particularly in regard to comparing the upper airway motor patterns at the end of the expulsion phase with those during subsequent swallowing. Experiments were conducted using both paralyzed and non-paralyzed decerebrate cats, in which recordings were obtained either from upper airway muscles, the diaphragm and abdominal muscles or from the nerves that innervate those muscles. The activity patterns of most nerves recorded in paralyzed animals were consistent with the behavior recorded in non-paralyzed animals from the muscles innervated by those nerves, with the exception of the cricothyroid and stylopharyngeus muscles. Vomiting can be divided into a series of retches followed by expulsion, which itself can be further subdivided into three phases. The final stage of expulsion, characterized by burst-like exaggerated activity of the laryngeal elevator thyrohyoid and the pharyngeal constrictors, proved to be different from pharyngeal swallowing, as judged from differences in the spatio-temporal patterns of the upper airway motor outputs. However, post-vomiting swallowing activity was still observed even after total deafferentation of the laryngeal and pharyngeal areas in paralyzed animals. It is therefore likely that the central processes for vomiting and swallowing closely relate in generating these two behaviors.

Role of pre-inspiratory neurons in vestibular and laryngeal reflexes and in swallowing and vomiting.

Fifteen pre-inspiratory (Pre-I) neurons were extracellularly recorded in the pre-Bötzinger complex and their involvements in vestibular (VN) and superior laryngeal (SLN) nerve reflexes and in fictive swallowing and vomiting were tested in decerebrated and artificially ventilated cats. Both type I (1 of 9) and type II (1 of 6) pre-I neurons could project to the contralateral ventral respiratory group region. Pre-I neurons changed their firing during VN and SLN respiratory reflexes and fictive swallowing and vomiting; different response properties were observed among individual pre-I neurons. These results suggest that pre-I neurons are a population of heterogeneous and multi-functional propriobulbar neurons.

Origin of laryngeal sensory-evoked potentials (LSEPs) in the cat.

Sensory-evoked potentials elicited by electrical stimulation of the superior laryngeal nerve were recorded at the dural surface on the cortex and the caudal medulla in anesthetized cats as a reflection of activities in the central afferent systems. These evoked potentials were named laryngeal sensory evoked potentials (LSEPs). LSEP was mainly composed of five components, N1, N2, N4, N12, and large biphasic potential (LBP). The peak latencies of these components were as follows: N1, 1.09 +/- 0.18 ms; N2, 1.93 +/- 0.19 ms; N4, 3.97 +/- 0.19 ms; and N12, 12.48 +/- 1.01 ms. LBP was a large component lasting from approximately 6 ms to 18 ms. The generator sources of these components were identified as follows: N1, nodose ganglion; N2, presynaptic potentials of the nucleus tractus of solitarius (NTS); N4, NTS complex including the postsynaptic potentials; and N12, activities of the frontal part of the orbital gyrus. The LBP was speculated to be generated from certain subcortical structures, such as the amygdala, the thalamus, the hypothalamus, and the basal ganglia.

Convergence of laryngeal afferents with different natures upon cat NTS neurons.

To clarify the convergence of laryngeal afferents within the nucleus tractus solitarius (NTS) in the cat, we examined in the medulla the response characteristics of superior laryngeal nerve (SLN) fibers and NTS neurons to mechanical and chemical stimulation applied to laryngeal mucosa by extracellular recordings. The response was recorded in 75 SLN primary afferent fibers (PAFs) and 92 NTS neurons. PAFs of the SLN consisted of numerous monomodal mechanosensitive fibers and a small number of chemosensitive and polymodal fibers. On the other hand, the majority of NTS neurons had a polymodal nature. Thus, laryngeal information is considered to be integrated in modality into NTS neurons. All mechanosensitive fibers received information from a small restricted field in the larynx. On the contrary, each NTS neuron responded to mechanical stimulation over a wide laryngeal field, indicating that information from different sites spatially converge on NTS neurons. Our results suggest that caudal NTS neurons play a cardinal role in integrating laryngeal afferents, which are thought to elicit laryngeal reflexes.

Convergence of afferents from the SLN and GPN in cat medullary swallowing neurons.

We demonstrated the convergence of information from the pharyngeal and laryngeal mucosa, transmitted by the glossopharyngeal nerve (GPN) and superior laryngeal nerve (SLN), in the nucleus of the tractus solitarius (NTS). First, the distribution of terminals of the GPN and SLN in the NTS was examined by an HPR tracing technique in cats, and the synapse formation of these neurons with NTS neurons was demonstrated by electron microscopy. The HRP-labeled SLN and GPN terminals were localized in a small area of the interstitial subnucleus of the NTS, slightly rostral to the obex, forming synapses with NTS neurons. Next, using extracellular recording in anesthetized cats, we determined whether or not swallowing-related neurons in the medulla oblongata receive peripheral inputs. Convergence of peripheral sensory inputs from the SLN and GPN was observed in more than 80% of the NTS cells. These results suggest that the NTS is not only a sensory-relay nucleus but also integrates information necessary for eliciting protective reflexes of the upper airway, such as swallowing.

Measurements of oxygen pressure in the vocal fold during laryngeal nerve stimulation.

To clarify the mechanisms of ischemic change in the vocal fold on phonation, model experiments were performed under various conditions by recording tissue oxygen pressure (Pto2) values under electrical stimulation of either the recurrent laryngeal nerves or external branches of the superior laryngeal nerves. In addition, autonomic nerve regulation of laryngeal vessels was estimated under administration of succinylcholine chloride. Oxygen pressures of the vocal fold were measured in the lamina propria and vocal muscle at the middle of the membranous portion. The Pto2 in the lamina propria showed a slight increase during lower-frequency stimulation and a slight decrease during higher-frequency stimulation of the recurrent laryngeal nerve. The Pto2 in the vocal muscle showed a decrease during stimulation of the recurrent laryngeal nerve. On the other hand, the Pto2 showed almost no change in the lamina propria or vocal muscle during stimulation of the external branch of the superior laryngeal nerve. It is supposed that an ischemic change in the vocal muscle on phonation results mainly from contraction of the vocal muscle. On the contrary, the ischemic change in the vocal mucosa on phonation does not appear to be directly caused by the contraction of the vocal muscle but by other factors, such as wavelike movement.

An experimental study of the circulation of the vocal fold on phonation.

The ischemic change of the vocal fold on phonation was studied with an oxygen electrode using the canine vocal fold. Oxygen pressures of a limited area of the vocal fold were measured in the lamina propria and vocal muscle at the middle of the membranous portion. The results are summarized as follows: oxygen pressure in each area decreased on phonation as compared with respiratory movement, an ischemic change of the vocal fold occurred on phonation, and the response in the lamina propria was less than that of the vocal muscle.

Detection of largyneal sensory-evoked potentials (LSEPs) in the cat.

We previously reported on evoked potentials elicited by electrical stimulation of the superior laryngeal nerve at an appropriate site on the dural surface as a reflection of activities in the brain stem and cortex in anesthetized cats. This evoked potential was called the laryngeal sensory evoked potential (LSEP). In this study we attempted to establish a less invasive procedure for measuring LSEP. The procedures were recording on the scalp using chloride-coated silver disk electrodes and stimulation by insertion of a bipolar platinum hooked wire electrode into the laryngeal mucosa. Evoked potentials could be detected using these less invasive procedures. The response morphologies and relative timing of LSEP components were quite similar for each method in a given cat. However, the amplitudes were slightly lower and the latencies were slightly prolonged with the less invasive techniques. These results suggest that this LSEP method might be applicable to human beings as a noninvasive method for evaluating the function of the laryngeal sensory pathway.