Takashi Tachimura

Comparison of Nasopharyngeal Growth between Patients with Clefts and Noncleft Controls

OBJECTIVE This study was a comparison of the cephalometric growth characteristics of the nasopharyngeal structures between UCLP and noncleft controls. METHOD Eighty patients with complete unilateral cleft lip and palate (UCLP group) and 82 noncleft controls (NCC group) were assigned to four developmental stages (i.e., stage 1, at 4 years; stage 2, at 8 years; stage 3, at 12 years; and stage 4, at 17 years of age). Measurements on the anteroposterior and the vertical dimensions were derived from reference lines and points of nasopharyngeal structures on the lateral cephalograms. RESULTS The results showed that there were no growth differences between the two groups at any stages in the regions of cranial base and cervical vertebrae, and that growth of the posterior maxilla in the UCLP group was significantly less at any stage in both A-P and vertical dimensions than in the NCC groups. As well, the nasopharyngeal triangle (Ho-At-PMP) in the groups showed almost parallel increase with stage, though with short vertical dimension in the UCLP group, and the soft palate length in the UCLP group was significantly less at stages 2, 3, and 4 compared to that in the NCC group. The adequate ratio (soft palate length/pharyngeal depth) in the UCLP group tended to decrease and was significantly less at stage 4 compared to that in the NCC group. CONCLUSIONS These results indicate that the growth of the cranial base and the upper cervical vertebrae is independent of the effect of clefts or of surgeries on clefts, and that the growth inhibition at the posterior maxilla results in morphologic disharmony of upper nasopharyngeal structures. This could be a potential factor for the reappearance of velopharyngeal incompetence at a later age.

Effect of placement of a speech appliance on levator veli palatini muscle activity during speech.

OBJECTIVE We have observed clinically that some speakers wearing a speech appliance for correction of velopharyngeal incompetence can blow with variable intensity without nasal air escape. This clinical finding suggests that tightness of velopharyngeal closure may be regulated in accordance with oral air pressure during blowing. The purposes of this electromyographic study were (1) to examine whether levator vell palatini muscle activity can be changed in relation to oral air pressure during blowing when the speech appliance is removed, (2) to clarify whether or not the change is related to the severity of velopharyngeal incompetence, and (3) to examine whether placement of a speech appliance can alter levator muscle activity into the equivalent of that of normal speakers during blowing. DESIGN Eight patients with repaired cleft palate, who routinely wear a palatal lift prosthesis (PLP) or a hybrid speech appliance of a pharyngeal bulb and palatal lift (bulb-PLP), served as subjects. Subjects were classified into one of two groups according to their speech appliance (PLP group and bulb-PLP group). Electromyography of the levator veli palatini muscle was recorded with a speech appliance in place and then with the speech appliance removed as the subject blew through a tube at three different effort levels. RESULTS In the removed condition, the change in levator activity in relation to oral air pressure was variable across subjects in the bulb-PLP group, whereas levator activity changed in relation to oral air pressure change for all subjects in the PLP group. However, levator activity changed in relation to oral air pressure with either speech appliance in place for all subjects irrespective of their speech appliance types. CONCLUSION The severity of velopharyngeal incompetence might be related in part to change in levator activity in association with oral air pressure. The effect of a speech appliance to correct velopharyngeal incompetence might consist not only of mechanical obturation of the velopharynx but also of alteration of velopharyngeal function to become similar to normal speakers. Moreover, it is likely that the velopharyngeal system could be well regulated so as to exhibit a consistent outcome of velopharyngeal function.

Morphological evaluation of changes in velopharyngeal function following maxillary distraction in patients with repaired cleft palate during mixed dentition.

Objective To describe the morphological changes of nasopharyngeal components after maxillary distraction and clarify whether the morphological characteristics are related to velopharyngeal function (VPF). Design Perceptual judgments of hypernasality and nasendoscopy were performed before and after treatment. Lateral cephalograms were obtained to describe the morphological changes. Setting Department of Oral and Maxillofacial Surgery, Miyazaki Medical College, Miyazaki, Japan. Participants Nine patients with repaired cleft palate in the mixed dentition stage underwent maxillary distraction using a face mask and an intraoral fixed appliance system. Outcome Measures The severity of hypernasality, velopharyngeal insufficiency, and measurements such as pharyngeal depth, velar length, and the rotation of the palatal plane were evaluated. Results Increase in pharyngeal depth was not always proportional to the amount of advancement. It depended on the posture of the posterior pharyngeal wall and the rotation of palatal plane. Conclusion Cephalometric measurements of the nasopharynx before and after surgery confirmed subsequent changes in VPF. These were suggested to be useful in predicting future VPF. When performing maxillary distraction in patients with cleft palate in the mixed dentition stage, and when velopharyngeal closure is found to occur by velar contact against the hypertrophied adenoid, patients should be counseled about risks of subsequent deterioration in their speech before surgery.

Oral air pressure and nasal air flow rate on levator veli palatini muscle activity in patients wearing a speech appliance

This study was designed to determine if levator veli palatini muscle activity can be elicited by simultaneous changes in oral air pressure and nasal air flow when a speech appliance is in place. The speech appliances routinely worn by 15 subjects were each modified experimentally by drilling a hole in the vertical center of the pharyngeal bulb. The air flow rate into the nasal cavity through the opening in the bulb was altered by changing the circular area of the opening in the bulb from the occluded condition (Condition I), to circular area of 12.6 mm2 (4 mm in diameter; Condition II), and then to 38.5 mm2 (7 mm in diameter; Condition III). Electromyographic activity was measured from the levator veli palatini muscle with changes in nasal air flow rate and oral air pressure. Levator veli palatini muscle activity was correlated with changes in nasal air flow and oral air pressure. Increases in levator veli palatini muscle activity were associated with increases in nasal air flow rate compared to oral air pressure changes. The results indicated that aerodynamic variables of nasal air flow and oral air pressure might be involved in the neural control of speech production in individuals wearing a speech appliance, even if the subjects exhibit velopharyngeal incompetence without using a speech appliance. Also, the stimulating effect of bulb reduction therapy on velopharyngeal function might be achieved through the change in aerodynamic variables in association with the bulb reduction.

Effect of Temporary Closure of Oronasal Fistulae on Levator Veli Palatini Muscle Activity

OBJECTIVE The objective of this study was to clarify electromyographically the effects of closing an oronasal fistula on levator muscle activity and oral air pressure in patients with velopharyngeal incompetence and in those with adequate velopharyngeal function. SUBJECTS Five patients with adequate velopharyngeal function and six patients with velopharyngeal incompetence were studied. All subjects had an oronasal fistula at the anterior third portion of the hard palate in spite of primary palatal closure using palatal push-back operation. OUTCOME MEASURES The smoothed electromyographic activity of the levator veli palatini muscle was measured with the fistula closed with a cotton swab dipped in saline and with the fistula left open. RESULTS Under the closed fistula condition, oral air pressure was greater than that observed under the open fistula condition irrespective of velopharyngeal function. Levator veli palatini muscle activity was significantly lower in magnitude under the condition of closure than under the open condition in the patients with adequate velopharyngeal function, whereas in those with velopharyngeal incompetence, it was not significantly changed. CONCLUSIONS The results suggest that velopharyngeal function is affected by temporary closure of an oronasal fistula, and that the magnitude of the effect is greater for subjects with adequate velopharyngeal function than for subjects with velopharyngeal incompetence.

Dentoalveolar Growth of Patients With Complete Unilateral Cleft Lip and Palate by Early Two-Stage Furlow and Push-Back Method: Preliminary Results

Objective This study examined dentoalveolar growth changes prior to the time of palatoplasty up to 3 years of age by the early two-stage Furlow and push-back methods. Subjects Thirty-four Japanese patients with complete unilateral cleft lip and palate (UCLP) treated with either a two-stage Furlow procedure (Furlow group: seven boys, eight girls) from 1998 to 2002 or a push-back procedure (push-back group; 12 boys, 7 girls) from 1993 to 1997. Method Consecutive plaster models were measured by three-dimensional laser scanner, before primary palatoplasty, before hard palate closure (Furlow group only), and at 3 years of age. Bite measures were taken at 3 years of age. Results In the Furlow group, arch length, canine width, first and second deciduous molar width and cross-sectional area, and depth and volume at midpoint showed greater growth than in the push-back group. In the Furlow group, the crossbite score was also better than in the push-back group at 3 years of age. In comparison with the push-back group, inhibition of growth impediment in the anterior region was observed in the horizontal direction in the Furlow group. In the midregion, it was observed in the horizontal and vertical directions, and in the posterior region it was observed in the horizontal direction. Conclusion The results demonstrate that the early two-stage Furlow method showed progressive alveolar growth. Therefore, the early two-stage Furlow method is a more beneficial procedure than the push-back method.

Change in palatoglossus muscle activity in relation to swallowing volume during the transition from the oral phase to the pharyngeal phase.

The purpose of this study was to examine whether the palatoglossus (PG) muscle is involved in the regulation of function during the transition from the oral to the pharyngeal phase. Seven normal adults participated in the study. Smoothed electromyography (EMG) signals of the PG muscle and levator veli palatini (LVP) muscle were collected. Each subject swallowed water at five different volumes: 12.5%, 25%, 50%, 100%, and 150% (or 200%) of his/her optimum swallowing volume. PG muscle waveform showed two patterns of activity: one of a single peak and the other of two peaks. There was no significant difference (p < 0.01) in the timing of emergence between the single peak and the second peak of the two-peak pattern. There were two patterns of PG muscle activity in response to a change in swallowing volume, i.e., one was a pattern in which the activity was correlated to the change in swallowing volume, the other was a pattern in which the activity was not changed but almost at the maximum activity level, irrespective of swallowing volume. We conclude that the PG muscle could be involved in the regulation of swallowing from the oral to the pharyngeal phase. The activity could be influenced by swallowing volume.

A cephalometric study by multivariate analysis of growth of the bony nasopharynx in patients with clefts and non-cleft controls

To clarify the characteristics of growth of the nasopharynx, comparison of the cephalometric growth of bones surrounding nasopharynx between 61 patients with complete unilateral cleft lip and palate (UCLP group) and 82 non-cleft controls (NCC group) was carried out. All of the subjects were divided into four developmental stages (i.e. stage 1 at 4 years of age, stage 2 at 8 years of age, stage 3 at 12 years of age and stage 4 at 17 years of age). Measurements on the antero-posterior and the vertical dimensions were derived from a coordinate system and points on bones surrounding the nasopharynx on lateral X-ray cephalograms, and results were analyzed by multivariate analysis and t-test. The results showed that (a) the posterior maxillary point (PMP) in the UCLP group was located more postero-superiorly than that in the NCC group, and this was the main factor that allows discrimination between the two groups and (b) the cranial base, posterior maxilla and the cervical vertebrae were found to be in independent in growth, however, the nasopharyngeal triangle connecting three points on these three bones (Ho: cranial base; PMP: posterior maxillary point; At: atlas) showed harmonious growth in both the UCLP and NCC groups.

Evaluation of fatigability of the levator veli palatini muscle during continuous blowing using power spectra analysis.

Objective The purpose of this study was to compare the fatigability of the levator veli palatini (LVP) muscle during blowing in speakers who exhibit velopharyngeal incompetence with that from normal speakers by means of power spectra analysis. Design All subjects were instructed to blow into a tube for more than 10 seconds at maximum possible effort. The LVP muscle activity (electromyography) was sampled at 2 kHz for 10 seconds from the time when the oral air pressure during blowing was stabilized. These samples were subjected to Fast Fourier Transfer analysis with analytic windows of 0.5-second width. The electromyography mean power frequency slope with respect to time for each subject was estimated. Participants Three speakers with repaired cleft palate and three normal speakers were selected as subjects. Results The slopes of the regression lines for all three subjects with repaired cleft palate were negatively signed with statistical significance (t test, p < .01). The slopes for all of the normal speakers were negatively signed, but these were not statistically significant. Conclusion These results suggest that the LVP muscle of speakers with repaired cleft palate who exhibit varying degrees of velopharyngeal dysfunction may deteriorate more easily in comparison with the LVP muscle of normal speakers.

Change in Levator Veli Palatini Muscle Activity for Patients With Cleft Palate in Association With Placement of a Speech-Aid Prosthesis

OBJECTIVE The purpose of this study was to examine whether a speech-aid prosthesis normalizes the activity of the levator veli palatini muscle for patients with cleft palate who exhibit velopharyngeal incompetence. DESIGN Each subject was instructed to produce repetitions of /mu/, /u/, /pu/, /su/, and /tsu/ and to blow with maximum possible effort. Electromyographic (EMG) activity of the levator veli palatini muscle was recorded with and without a hybrid speech-aid prosthesis in place. PARTICIPANTS The participants were five patients with repaired cleft palate who were routinely wearing a hybrid speech-aid prosthesis. RESULTS With the prosthesis in place, the mean value of levator activity changed positively in relation to oral air-pressure change during blowing. Differences in levator activity in relation to speech samples were similar to those in normal speakers. With the prosthesis in place, levator activity for speech tasks was less than 50% of the maximum levator activity for all subjects. The findings were similar to those reported previously for normal speakers. CONCLUSION Placement of the prosthesis changed EMG activity levels of the levator veli palatini muscle to levels that are similar to normal speakers. It is possible that, with the increase in the differential levator activity between speech and a maximum force task, the velopharyngeal mechanism has a greater reserve capacity to maintain velopharyngeal closure compared with the no-prosthesis condition.